Abstracts of the 1st Sustainable Bioenergy and Processes Conference

ISBN: 978-1-991213-71-6

ABSTRACTS OF THE 1ST SUSTAINABLE BIOENERGY AND PROCESSES CONFERENCE AND 13 - 15 December 2021

Cape Town (Hybrid)

Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

ABSTRACTS OF THE 1ST SUSTAINABLE BIOENERGY AND PROCESSES CONFERENCE 13 - 15 December 2021 Cape Town (Hybrid)

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Development of silica gel catalyst support for fast pyrolysis of biomass using layered double hydroxide Danya Maree, Mike Heydenrych University of Pretoria, Pretoria, South Africa

Abstract The use of oil from fast pyrolysis of biomass as a substitute for conventional fossil fuels is being examined, but there is scepticism surrounding its feasibility due to its acidity, high water content, instability, and low calorific value. Instability and low calorific value are caused primarily by high elemental oxygen content in the oil. One way to improve the oil quality is to study the effects of insitu catalysts. An active catalyst which is of interest due to its reported ability to facilitate certain mechanisms that are favourable in oxygen reduction, is a nanostructured material called layered double hydroxide (LDH). Few studies have attempted to optimise the use of this catalyst in fast pyrolysis systems. To test its efficiency, it was necessary to develop an optimal catalyst support material. This was done by synthesising mesoporous silica gels containing pre-made Mg/Al-LDH and Ca/Al-LDH. High surface areas were produced by accurate control of the synthesis pH. The synthesis pH was instrumental in the variation of support material characteristics such as BET surface area and average pore width, with BET surface area decreasing, and pore width increasing, as pH increased.

This study will show how significant improvements in yield, calorific value and desired functional group concentrations of E. Grandis fast pyrolysis oils can be achieved through variation of the support material characteristics. Understanding the synthesis conditions required for improved silica catalyst supports will be helpful to examine the effects of future powdered catalysts in similar processes.

Keywords: fast pyrolysis; catalysts; layered double hydroxide; support material characteristics

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Characterization of sugar effluent from a sugar milling industry in the KwaZuluNatal province of South Africa for biogas production Zikhona Tshemese, Nirmala Deenadayalu, Linda Linganiso, Maggie Chetty Durban University of technology, Durban, South Africa

Abstract Sugar industry is one the biggest contributors to the environmental pollution in the modern world.

The effects are specifically felt by the aquatic environment which in turn affects the human beings as they depend (partially and otherwise) on the aquatic creatures such as fish for food resource (Pawar et al., 1998). Also, water demands are growing continually as human population increases although the supply of water is diminishing (Demirel and Yenigun, 2004). The disposal of the effluent from industries to water streams becomes detrimental as it does not only disturb the aquatic life but also the water quality that is used for domestic and agricultural purposes (ThambavaniD et al., 2012).

Effluent discharging industries include thermal power plants, paper mills, oil refineries, sugar mills etc (Saranraj and Stella, 2014). The composition of this effluent is total suspended solids, chemical oxygen demand, biological oxygen demand, heavy metals and sometimes the total dissolved solids (Khan et al., 2003). Treatment and reuse of industrial effluent (wastewater) then becomes a necessary step to meeting the environmental strain (Barman et al., 2000, Kisku et al., 2000). One way of effectively solving the crisis of industrial wastewater is through treating while making additional useful products such as biogas and electricity. The aim of the present paper is to do a thorough analysis of the effluent from sugar milling industry for production of biogas and electricity.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Extraction of caffeine from spent coffee grounds.

Nikita Singh1, Manimagalay Chetty2, Nirmala Deenadayalu3 1

Department of Chemical Engineering, Durban University of Technology, Durban, South Africa.

2

Department of Chemical Engineering, Durban University of Technology, Durban, South Africa.

3

Department of Chemistry, Durban University of Technology, Durban, South Africa.

Abstract This study aims to advance the study in the field of spent coffee grounds valorisation through caffeine recovery. In this research study, the effect of temperature, reaction time and solid-to-liquid loading ratio on the yield of caffeine extracted from spent coffee grounds was investigated. Simultaneously, the best extraction solvent between (i) dichloromethane , (ii) 1-ethyl-3-methylimidazodium chloride and (iii) water will be established. Prior to the extraction of caffeine, characterisation of spent coffee grounds using Technical Association of the Pulp and Paper (TAPPI) methods was carried out. Variations of parameters were established using the Box-Behnken design of experiment (DOE) methodology which varied the parameters being investigated; temperature range, reaction time and solid-to-liquid loading ratio. For the extraction process, both the conventional method and green method will be investigated. The conventional method includes solid-liquid extraction, vacuum filtration, liquid-liquid extraction and purification, whereas the green method only makes use of a Parr pressure reactor where solid-liquid extraction is carried out. From the above scenarios, we can establish the relationship between each extraction solvent against each parameter, the extraction solvent against both conventional method and green method. High Performance Liquid Chromatography (HPLC) will be used to quantify the yield of extracted caffeine. Recrystallization of the highest caffeine yield runs will be analysed using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) to analyse the crystalline structure and purity, as well as characterise the extracted caffeine. The expected yield of caffeine ranges between 4.67 - 8.0 mg.g-1 SCG. This overall study of caffeine extraction is a promising solution and already fits well within the established trading market.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Biogas-fuelled absorption refrigeration as a means of reducing post-harvest losses in rural Sub-Saharan Africa Louis Wentzel, Johann Görgens, Eugéne van Rensburg Department of Process Engineering, Stellenbosch University, Stellenbosch, South Africa

Abstract Post-harvest losses are particularly prevalent in the food value chains of Sub-Saharan Africa (SSA), characterised by poverty, food insecurity and poor infrastructure. This project combined anaerobic digestion (AD) and absorption refrigeration (AR) to provide off-grid cold storage in SSA and focussed on the artisanal fisheries of Lake Victoria to demonstrate the utility of this technology. Modern cold storage is not accessible to fisherfolk, traditionally relying on drying to preserve their catch, which reduces the quality and quantity of retailed fish. The main objective of the study was to prototype a biogas-fuelled aqua-ammonia absorption refrigerator to determine its biogas consumption rate and thermodynamic performance. A pipe injection burner was designed to convert a 42 L absorption refrigerator to run on a mixture of 59.2% methane and 40.8% carbon dioxide, which simulated a standard biogas mixture. This prototype was used as proof of concept and achieved cold storage temperatures that decreased from 6.4 to -19 ˚C as the normalised biogas flowrate was increased from 0.51 to 0.74 m3 day-1. The thermodynamic performance of this prototype informed an empirical model that determines the biogas consumption rates of larger absorption refrigerators at various temperatures. Two biomethane potential (BMP) assays with two objectives were performed to determine the potential biogas production rates of biomass available in SSA. The first BMP assay considered the co-digestion of fish effluent with cow manure, maize stover, water hyacinth and reeds, respectively, to determine whether co-digestion achieves statistically significant synergetic effects due to an improved nutrient balance. The second BMP assay investigated whether the ensilage of maize stover, water hyacinth and reeds, respectively, increases the BMP and/or digestion rate because hydrolysis takes place during ensilage. The final objective of this study was to combine the empirical results from the biogas-fuelled absorption refrigerator and the BMP assays with extrapolation coefficients to design the large-scale AD-AR dual system.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Pyrolysis of Canarium schweinfurthii hard-shell for bio-oils as clean energy precursors: Investigation on thermochemical characteristics Kabir Garba1, Yakub Mohammed Isah1, Abakr Yousif Abdalla2, Isa Yusuf Makarfi3, Bassim H. Hameed4 1

Department of Chemical Engineering, Abubakar Tafawa Balewa University, Bauchi, Nigeria.

Department of Mechanical, Manufacturing and Material Engineering, The University of Nottingham Malaysia Campus, Selangor Darul Eshan, Malaysia.

3 School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, South Africa.

2

4

Department of Chemical Engineering, College of Engineering, Qatar University, Doha, Qatar

Abstract Canarium schweinfurthii hard-shell is among the rich biomass resource found in Nigeria. Therefore, it is important to convert the hard-shell to valuable materials, particularly from the perspective of renewable materials production. The study described the possibility of using the Canarium schweinfurthii hard-shell via intermediate pyrolysis to bio-oils as resources for clean fuel. The pyrolysis was accomplished using a fixed-bed reactor at temperatures from 450-600 °C, 200 mL/min nitrogen flowrate, 10 oC/min heating rate and 30 min reaction time. The physical and chemical characteristics of the bio-oils that are important for biofuel characteristics were determined. The results revealed that the yields of the bio-oils obtained at the different temperatures are from 16.5843.50 wt% and 28.63–36.75 wt%, respectively. Oxygenated aromatic compounds and other saturated are the major chemicals of the bio-oils. The bio-oils have energy densities sufficient to serve as renewable fuel precursors. The pyrolysis followed multi-step kinetics, where the diffusion mechanisms of the Coats–Redfern kinetics best described the pyrolysis in the active zone. The values of the thermodynamic parameters informed that the overall pyrolysis reaction was endothermic and non-spontaneous.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

MODELING AND EXPERIMENTAL STUDY OF THE COMBUSTION OF TARRED PRODUCER GAS IN AN EJECTOR Alexander Kozlov, Anatoly Levin, Igor Donskoy, Maxim Penzik, Alexey Safarov Melentiev Energy Systems Institute of Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russian Federation

Abstract The operation of an ejector-type reactor, which is part of a multistage gasifier, for the combustion of tarred pyrolysis gas has been studied. The multistage gasifier developed by the authors consists of three interconnected reactors – the pyrolysis reactor , the afterburning reactor of the tarred producer gas and the gasification reactor . The stepwise scheme of organizing the process of gasification of woody biomass makes it possible to produce generator gas that does not contain tar. In this case, a key issue in the development of such gas generators is the question of organizing an effective combustion process of tarred producer gas. The developed reactor is a gas ejector into which heated air (600 ° C) is supplied through a nozzle, and due to the created under pressure, the tarred pyrolysis gas is fed into the mixing chamber (600-800 ° C) from the pyrolysis reactor where the burning of tarred producer gas is carried out. For a numerical study of the processes occurring in the ejector, a kinetic simulation of the burning of tarred pyrolysis gas was performed. In modeling, a hierarchical approach was used to construct the mechanisms of chemical reactions: the combustion mechanism of [H, O, C1] systems were taken as a basis, which was obtained by reducing GRI-MECH 3.0, then the mechanism was supplemented with toluene oxidation reactions. Toluene is a model compound for representing the tar resulting from pyrolysis. The resulting kinetic mechanism involves 146 reactions between 49 particles. The composition of the producer gas was set according to the results of experimental studies of the pyrolysis of woody biomass in an auger reactor. It was established that at low tar concentrations, a non-monotonic dependence of its conversion on temperature is observed. It was also determined that the decomposition of toluene proceeds in two different kinetic ways at temperatures below and above 1300 K. Low-temperature decomposition of toluene is characteristic of the reactions of the pyrolytic decomposition of aromatic compounds. With high temperature decomposition, the contribution of the reaction paths associated with oxidative destruction increases. Using the COMSOL Multiphysics CFD package, aerodynamics was calculated for a gas ejector. The calculated fields of temperature, velocity, the density of media, streamlines were obtained. Numerical experiments confirmed the convergence of the obtained algorithms for the calculation of turbulent flow in the mass flow range from 1 to 4 g/s.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Multi-criteria assessment of biomass gasification-based hybrid energy systems in remote areas Vladislav Shakirov, Alexander Kozlov Melentiev energy systems institute, SB RAS, Irkutsk, Russian Federation

Abstract Power supply of areas remote from power systems is often provided by diesel power plants. Such local power systems are characterized by high cost of power generation, low environmental friendliness.

Hybrid energy systems (HES) with renewable energy sources play a great role in eliminating these shortcomings [1]. In remote areas, where logging, timber processing is carried out, it is reasonable to consider the technology of biomass gasification as the basis for HES. The techno-economic optimization of HES has been conducted in many studies using the HOMER software [1, 2]. Since the HOMER optimization procedure is based on an economic criterion, multicriteria approaches have been developed to take into account technical, environmental, and social aspects [3, 4]. The disadvantages of these approaches include the use of several methods of multicriteria analysis, and consideration a large number of criteria. This not only makes it difficult for the decision maker to analyze the problem, but also increases the ability to choose an ineffective alternative. This study proposes an approach for multi-criteria selection of a gasification-based HES using the SMARTS technique taking into account a limited number of the most important criteria and the uncertainty of information.

At the second step of the proposed technique, a set of criteria and acceptable estimates for them are determined. The economic efficiency of a HES is assessed by the levelized cost of energy; environmental efficiency – by CO2 emissions; technical efficiency – by the number of starts of a biomass gasifier or diesel generator and it average load; social efficiency – by the share of load coverage using wind or solar energy. At the third step, using the HOMER software, a set of alternative options of HES with a different composition of energy sources is formed. Additional options are being formed with an increased capacity of storage devices, providing a more uniform operation of the biomass gasifier.

The numerical example is considered for a multi-criteria choice of a gasification-based HES in Malaya Kema village (45.42oN, 137.15oE). Logging and timber processing is carried out in the considered area.

The village is located on the shore of Sea of Japan, which facilitates the delivery of equipment. In the immediate vicinity of the village, the Kema-Amginsky National Park is being designed, so the area has the prospect of developing ecotourism. In this regard, environmental and social criteria are of great importance.

Using the methodology, a gasification-based HES was selected, which provides high performance according to the above criteria.

References

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid [1] Akram F, Asghar F, Majeed MA, Amjad W, Manzoor MO, Munir A. Techno-economic optimization analysis of stand-alone renewable energy system for remote areas. Sustainable Energy Technologies and Assessments. 2020.;38:100673.

[2] Li J, Liu P, Li Z. Optimal design and techno-economic analysis of a solar-wind-biomass off-grid hybrid power system for remote rural electrification: A case study of west China. Energy. 2020.;208:118387.

[3] Ukoba MO, Diemuodeke OE, Alghassab M, Njoku HI, Imran M, Khan ZA. Composite Multi-Criteria Decision Analysis for Optimization of Hybrid Renewable Energy Systems for Geopolitical Zones in Nigeria. Sustainability. 2020.;12(14).

[4] Elkadeem MR, Kotb KM, Ullah Z, Atiya EG, Dán A, Wang S. A two-stage multi-attribute analysis method for city-integrated hybrid mini-grid design. Sustainable Cities and Society. 2021.;65:102603.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Steam-activated Eucalyptus grandis biochar as a potent plant nutrient carrier Tsholofelo Lekhuleni, Ryan Merckel Department of Chemical Engineering, University of Pretoria, Pretoria, South Africa

Abstract Nutrient-loaded biochars have the potential to remediate of degraded soils and enhance of food production. Following from previous work where the dependence of adsorptive performance on material and synthesis route was demonstrated for NH4-N sorption, the sorption affinity of Eucalyptus grandis biochar for several other plant nutrients from wastewater is explored. Sorption is carried by recovering nitrogen and phosphorus moieties using a packed bed bench-scale reactor. Preliminary results have shown that without activation of neat biochar (BET surface area = 163.4 m2 g1 ), adsorption efficiency for phosphorus is only 11.5 % at pH 7.4. Steam-activation improves surface area considerably (BET surface area = 423.1 m2 g-1) and is accompanied by severe modification to the surface morphology observed as elliptical and wide pitting, which is generally absent from neat biochar. Consequently, biochar that has been steam-activated for 2 hours achieves effluent-derived phosphorus adsorption of around 100.0 %.

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Waste to energy circular economy as a way to mitigate the problem of municipal solid waste in Brazil Luane Jesus Santos, Lucas Menezes Pereira, Francisco Mendonça Freires Universidade Federal da Bagia, Salvador, Brazil

Abstract Population growth has contributed to a greater use of material and natural resources, with consequent increase in the generation of Municipal Solid Waste (MSW). People have increasingly demanded greater power generation, which causes severe environmental impacts, as well as potential risks to public health [1]. To monitor the evolution of environmental impacts, it is up to society to know the risks and promote means to mitigate them [2]. In order to solve this problem, it was created the concept of Circular Economy, in which the value of products, materials and resources is kept in the economy for as long as possible, and then the generation of waste is minimized, and together with Waste to Energy (WtE), which is a way to recover the energy of waste materials in the form of usable heat, electricity or fuel, [3] has contributed to the reduction of carbon emissions. Together, they can be used as a complementary technology for the treatment of waste fractions that cannot be recyclable, thus seeking to avoid unnecessary use of materials and optimizing natural resources by providing a sustainable solution to fill and shorten the gap between energy generation and environmental concerns [4]. Thus, the general objective of this work is to analyze the synergy between Waste to Energy and the circular economy as a way to mitigate the problem of Municipal Solid Waste (MSW) in Brazil. Therefore, it was necessary to analyze the generation of MSWs in the country and the systems that enable the recovery of these wastes, allowing them to be used to obtain energy, which reduces the amount of MSW that are discarded in landfills and other places, situation in which their energy content would not be used and also contributes to the increase in diversification of the Brazilian energy matrix.

Keywords: Circular Economy, Municipal Solid Waste, Waste to Energy References [1] ALFAIA, R. G. D. S. M.; COSTA, A. M.; CAMPOS, J. C. Municipal solid waste in Brazil: A review. Waste Management & Research, v. 35, n. 12, p. 1195-1209, 2017. ISSN 0734- 242X. [2] GUPT, Y.; SAHAY, S. J. W. M. Review of extended producer responsibility: a case study approach.

Waste Management & Research, v. 33, n. 7, p. 595-611, Jul. 2015. ISSN 0734- 242X. Doi: 10.1177/0734242X15592275.

[3] ZHAO, X.G., JIANG, G.W., LI, A., WANG, L., 2016. Economic analysis of waste-to-energy industry in China. Waste Manage. 48, 604–618.

[4] BAJIC´, B.Z., DODIC´, S.N., VUCˇUROVIC´, D.G., DODIC´, J.M., GRAHOVAC, J.A., 2015. Wastetoenergy status in Serbia. Renew. Sustain. Energy Rev. 50, 1437–1444.

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Biochar synthesis and in-situ activation in a rotary kiln William Baasch, Ryan Merckel Department of Chemical Engineering, University of Pretoria, Pretoria, South Africa

Abstract Not all biochar is created equally. A bench-scale rotary kiln is presented as a pragmatic tool for the evaluation of the optimal conditions required during pyrolysis of woody biomass. The design features variable angle adjustment, rotary speed control, temperature control, as well as feedstock control.

The process allows for the introduction of super-heated steam and other oxidising fluids into the rotary kiln for the in-situ activation of biochar. Several thermocouples located successively along the interior of the rotary kiln provide direct measurement of thermal gradients. A customised data logging system with various other energy measurements grants the rigorous quantification of mass and energy fluxes, thereby enhancing insight into the production of activated biochar and co-products. It is intended to use the knowledge generated from this bench-scale study for the improvement of the economic feasibility where nutrient-loaded activated biochar for use in the agricultural sector is concerned.

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Effect of Operating Conditions on the hydrothermal valorization of sewage sludge.

Mbaliyezwe Madikizela1, Yusuf Isa2 1

Durban University of Technology, Durban, South Africa.

Johannesburg , South Africa

2

University of the Witwatersrand,

Abstract The accelerated population growth, in conjunction with the rapid urbanisation rate, are the principal driving forces behind the augmented volumes of municipal sewage sludge generated worldwide. The traditional approaches of sewage sludge treatment, which include landfilling and agricultural application, are no longer within the realms of possibility due to rigorous regulations, deficiency in the capacity of land available and the environmental and health adversities associated with detrimental constituents of sewage sludge. The population and urbanisation advancements do not only influence the emergent volumes of sewage sludge, but they also instigate fundamental provocations to the global energy demand. The reliance on fossil fuels poses a significant threat, not only to sustainable development, however they are also hugely responsible for the cumulative carbon dioxide and other greenhouse gas (GHG) emissions that deteriorate the environment, trigger global warming and deleteriously impact the livelihood of all life on earth. In line with the quest for sustainable and renewable alternative energy sources, the thermochemical treatment of municipal sewage sludge has a triple advantage of valorising the abundant volumes of the sludge, addressing the injurious nature of conventional fuels to the environment and seeking to bridge the gap as their supply diminishes.

This study followed a quantitative approach, with the purpose to convert municipal sewage to valuable bio-oils. The sewage sludge was subjected to hydrothermal liquefaction in 60 ml stainless steel batch reactors, where the effect of temperature, solvent composition, and solvent content were investigated, and all the other process parameters were maintained at a constant. The six temperatures that were explored were 220ºC, 250ºC, 280ºC, 310ºC, 340ºC, 370ºC. The two solvents investigated were de-ionised water (H2O) and ethanol (E) which were applied in the following compositions: 1:0, 1:1 and 0:1 (H2O:E). The five solvent contents investigated were 75%, 80%, 85%, 90% and 95%.

The process yielded bio-oils, solid phase and gaseous products and an aqueous phase.

Dichloromethane was used as an extraction medium. The obtained results revealed that the temperature, solvent type and solvent content had a significant influence on the yield of bio-oil produced while temperature was the most influential out of the three parameters. When temperatures approached supercritical conditions of water, a notable decline in the bio-oil yields was observed. For each temperature, the bio-oil yields initially increased until about 85% solvent content, and then slightly decreased thereafter. The highest bio-oil yields were achieved at 310ºC and the best yields were obtained when the ratio of H2O and E were 1:1. This study found that the optimum operating conditions were obtained at 310ºC, 85% solvent content and a 1:1 composition of H2O and ethanol; the bio-oil yields at those conditions was determined to be 40,6 wt%.

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Experimental investigations on utilisation of ethanol (E100) in an automotive spark ignition engine Nidhi ., K. A. Subramanian IIT Delhi, New Delhi, India

Abstract Experimental investigation was carried out on a single cylinder automotive spark ignition engine to study its combustion, performance and emission characteristics using ethanol (E100) as fuel. Engine speed was varied from 3200 rpm to 4200 rpm. The spark timing with ethanol was advanced than gasoline. The experimental results indicate that with increase in speed, the peak cylinder pressure increased with ethanol and was almost equal to base gasoline. At lower speed, brake power of the engine decreased by 25% with ethanol while it dropped by 8.3% at high speed as compared to gasoline. Hence, the power output improved with the advanced spark timing (350 bTDC) as compared to base gasoline (320 bTDC). Brake thermal efficiency of the engine was higher with ethanol due to high flame velocity of ethanol than gasoline. Hydrocarbon (HC) emission increased at all the speeds with ethanol. Nitrogen oxides (NOx) and carbonmonoxide (CO) emissions decreased with ethanol than that of base gasoline. NOx emission decreased by 14.9% and 28.7% at lower and higher engine speeds respectively while CO emission decreased by 67.8% and 33.6% at both the speeds due to presence of oxygen in its molecular structure. CO2 emission increased with ethanol at all the speeds, with 38.8% at higher speed as compared to base gasoline. It was concluded from the study that the engine performance with ethanol is better and the emissions are lower compared to base gasoline in an unmodified engine. Operating parameter such as spark timing is varied in this study to achieve better performance of the engine with ethanol. It is suggested to adopt modification of the engine such as increase of compression ratio of the engine and ethanol- methanol blends (M25E75 and M75E25) to harness maximum potential of ethanol.

Keywords: Ethanol (E100), Spark Ignition Engine, Spark Timing, Power, Emissions

References [1] Omar I. Awada, R. Mamata, Obed M. Alib, N.A.C. Sidikc, T. Yusafd, K. Kadirgamaa, Maurice Kettnere, Alcohol and ether as alternative fuels in spark ignition engine: A review, Renewable and Sustainable Energy Reviews 82 (2018) 2586–2605.

[2] Mortadha K. Mohammed, Hyder H. Balla, Zaid Maan H. Al-Dulaimi, Zaid S. Kareem, Mudhaffar S. Al-Zuhairy, Case Studies in Thermal Engineering 25 (2021) 100891.

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EDIBLE AND COSMETIC OIL REFINING USING ACTIVATED CARBON FROM MARULA SHELLS PLACXEDES SIGAUKE1, EDISON MUZENDA1,2, TIRIVAVIRI MAMVURA1, OREFILE THULANI MNGQIBISA1 1

BOTSWANA INTERNATIONAL UNIVERSITY OF SCIENCE AND TECHNOLOGY, PALAPYE, Botswana.

UNIVERSITY OF JOHANNESBURG, JOHANNESBURG, South Africa

2

Abstract EDIBLE AND COSMETIC OIL REFINING USING ACTIVATED CARBON FROM MARULA SHELLS OREFILE THULANI MNGQIBISA1*, MUZENDA E1,2, MAMVURA T1, SIGAUKE P1 1. Department of Chemical, Materials and Metallurgy Engineering, Faculty of Engineering and Technology, Botswana International University of Science and Technology, Plot 10071 Boseja Ward, Palapye, Botswana. sp19100021@studentmail.biust.ac.bw 2. Department of Chemical Engineering Technology, University of Johannesburg, Johannesburg 2001, South Africa Marula products can be used in food, cosmetics, base oil for soap and as nose-drops for infants(Francis and Tahir, 2016). Marula shells are not considered to have commercial value because of lack of available and affordable processes to convert into value-added commodities (Molelekoa et al., 2018).

The carbons from Marula shells were found to be hard and suitable for producing activated carbon (Ncube et al., 2011). The aim of this research was to refine crude marula oil and crude sunflower oil using activated carbon produced from marula shells. Activated bentonite (Tonsil) was used as a basis for comparison. Formation of activated carbon with ratio 1:1 involved direct activation of marula shells with KOH in a tubular furnace. Vacuum bleaching was done on crude marula oil and crude sunflower oil. Acid value, β-carotene and free fatty acids (FFA) content were measured on both crude and refined oil for both oils. Results showed that activated carbon from marula shells can be used as an adsorbent since color changed from cloudy to clear color after bleaching. Acid values, FFA and β-carotene content reduced after bleaching and were 3.95mgKOH/g oil, 3.65mgKOH/g oil and 3.37mgKOH/g oil for crude sunflower oil (CS), bleached sunflower oil with Tonsil (BST) and bleached sunflower oil with activated carbon (BSAC) respectively. FFA values were 1.97mgKOH/g oil, 1.83mgKOH/g oil and 1.69mgKOH/g oil for CS, BST and BSAC respectively. Carotenoid content was 0.7ppm, 1.05ppm and -0.1ppm for CS, BST and BSAC respectively. Carotenoid content for CM, BMT and BMAC were 6ppm, 11ppm and 1ppm respectively. The research concluded that refining marula oil and sunflower oil using activated carbon from marula shells will result in utilizing waste and reducing processing costs.

References 1. Francis, K. A. and Tahir, A. R. (2016) ‘Evaluation of the physicochemical properties of Northern Ghana Sclerocarya birrea seed oil and proximate analysis of the process waste’, 10(4), pp. 48–53. doi: 10.5897/ajfs2016.1425.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid 2. Molelekoa, T. B. J. et al. (2018) ‘Potential of marula (Sclerocarya birrea subsp. caffra) waste for the production of vinegar through surface and submerged fermentation’, 114(11–12), pp. 77–83. doi: 10.17159/sajs.2018/4874.

3. Ncube, I. et al. (2011) ‘Activated carbon produced from agro-forestry wastes using single-step steam pyrolysis’, 37(4), pp. 239–244. doi: 10.5276/JSWTM.2011.239.

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Catalytic pyrolysis of torrefied olive stone for production of potential petrochemical alternatives Elvis Ganda1, Renata Migliaccio2, Antonio Coppola2, Giovanna Ruoppolo2, Massimo Urciuolo2, Paola Brachi2, Fabrizio Scala1, Piero Salatino1 1

Università degli Studi di Napoli Federico II, Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale (DICMaPI), Napoli, Italy. 2Istituto di Scienze e Tecnologie per l’Energia e la Mobilità Sostenibili – Consiglio Nazionale delle Ricerche, Napoli, Italy

Abstract Olive stone a drupe endocarp lignocellulosic material has been identified as a high-lignin feedstock with great potential for the production of biofuels and biochemical aromatic derivatives (Mendu et al., 2011), with great abundance and availability within the Mediterranean region with the region responsible for producing 97% of the world total olive consumption (Sánchez and San Miguel, 2016, Trubetskaya et al., 2020). The adoption of olive stone in thermochemical applications has been spurred on by its favourable physicochemical characteristics, which include low moisture content, uniform size, high energy density and very low ash content compared with most waste biomass streams which reduces the operational costs associated with its usage (Trubetskaya et al., 2020). The pyrolytic deconstruction of such high-lignin feedstocks produces greater yields of lignin based pyrolytic products such as phenolics which range from hydroxyl, alkyl and alkoxy substituted compounds that have great potential to serve as replacements for petroleum-derived phenols in applications such as lubricant additives, phenolic resins, polymer additives and agrochemicals (Lazaridis et al., 2018, Cao et al., 2017, Ma et al., 2020).

In this study, torrefaction pretreatment was employed prior to the catalytic fast pyrolysis to improve the stability of the recovered bio-oil and improve selectivity towards desirable fraction of stable oxygenates. The torrefaction in this study was carried out in batch fluidised bed reactors at temperatures between 200-250 °C, then subsequently fast pyrolyzed at 500 °C in the presence of a catalytic bed. The intensification of the relative lignin content after torrefaction increased the selectivity towards phenolic derivatives with the ZSM-5 catalyst improving the yields of alkyl-phenols such as phenol;2-methyl-phenol;p-cresol;hydroxytoluene which as highlighted earlier could play a role in substituting some of the traditional petroleum derived phenols in various industries.

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SELECTIVE REMOVAL OF Pb(II) FROM WASTEWATER USING MODIFIED CELLULOSE NANOCRYSTALS (CNCs) WITH ETHYLENEDIAMINETETRAACETIC ACID (EDTA): ISOTHERM, KINETICS, AND THERMODYNAMIC STUDIES Musamba Banza, Rutto Hilary VAAL UNIVERSITY OF TECHNOLOGY, Vanderbijlpark, South Africa

Abstract Cellulose are renewable raw materials that can be used for the development of an adsorbent for heavy metal ions removal. In this study, CNCs were modified with EDTA and used as adsorbents to remove Pb(II) ions from a mixture of Fe (II), Cu (II), Cr (VI) and Co(II) metals ions synthesized solution. The effect adsorption of Pb (II) ions onto modified CNCs were investigated by varying the pH (3-9), adsorbent dosage (5-25 mg. L-1), initial concentration (50-500 mg. L-1) and temperature (298- 318 K).

The modified CNCs were characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and BET (Brunauer-Emmett-Teller) surface area. SEM results showed that CNCs is porous, has narrow particles size and FTIR results revealed that the functional group responsible for the lead ions removal were mainly carboxylates (-COO2-). The XRD diffraction pattern showed that the CNCs possessed the cellulose crystalline configuration. The modified CNCs had a slightly higher BET surface area and bigger pore diameter than the unmodified CNCs. The results revealed that the maximum adsorption capacity of Pb(II) was 250 ± 0.88 mg. L-1 and the percentage removal was 95.05± 0.79%. The optimum process conditions were as follows; pH 5, CNCs dosage 25 mg. L-1, initial concentration 400 mg. L-1, temperature 313 K, and the adsorption equilibrium time was reached at 300 min. The equilibrium data fitted the Langmuir model and was well explained in terms of pseudo-second-order kinetics. Thermodynamic studies showed that the adsorption was endothermic and spontaneous in nature.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Effect of FA and Dissolved Oxygen concentration as controlling parameters on partial nitritation using lab scale sequencing batch reactors SLK Kiambi Durban University of technology, Durban, South Africa

Abstract Nitrogen in the form of ammonium in wastewater have become a significant concern throughout the world (Ni, Joss and Yuan 2014). The presence of ammonium nitrogen results in eutrophication that stimulate algal growth that may harm aquatic life. There are several techniques to remove nitrogen.

These methods include physical, chemical, and biological methods. Biological nutrient removal (BNR) has become the most commonly used method to remove nitrogen due to it efficient and cost-effective nature (Wang and Yang 2004). These methods include nitrification, denitrification, and anaerobic ammonium oxidation.

Attention is currently shifting towards partial nitritation and anaerobic ammonium oxidation as the preferred technology since it has been identified as most environmentally and economically friendly method.

It has been previously reported that the long term stability of the nitritation is a huge problem and DO is one of the main parameters that are key to achieve a stable partial nitritation process (Blackburne, Yuan and Keller 2008; Miao et al. 2015). Therefore, it is important to control and monitor the DO concentration in order maintain a certain DO concentration to favour a specific bacterial growth.

Ammonium oxidizing bacteria and nitrite oxidizing both need oxygen to oxidize the ammonium and nitrite respectively. The problem with the two groups of bacteria is that they compete for the oxygen present in the system. The AOB have been observed to dominate in systems with lower DO concentrations whereas NOB have been observed to dominate and outcompete AOB in systems with high DO concentrations (Liang et al. 2011).

By controlling the DO or air flow rate enables selective enrichment of the AOB as this limited DO concentration is not enough for NOB hence the washout of the NOB. According to previous studies, ammonium oxidizing bacteria have a high oxygen affinity than nitrite oxidizing bacteria (Blackburne, Yuan and Keller 2008; Pérez et al. 2014; Chen et al. 2016). This means that AOB get first preference in the dissolved oxygen present in the system over NOB. The pH is one of the main parameters that influence the success of partial nitritation. According to (Li et al. 2014), setting the pH to 8.17-8.19 enables stable partial nitritation to be achieved. Lv et al.

(2016) stated that pH does not only have an effect on partial nitritation but also has an effect on the nitrous acid emission. According to Ruiz et al (2003), the pH lower than 6.45 and higher than 8.95 then was major drop in nitrification which showed that there was complete inhibition of both AOB and NOB. Peng and Zhu (2006) reported that regulating the pH is commonly used in order to achieve partial nitrification due to inhibition differences between AOB and NOB.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid Free Ammonia (FA) is a substrate that affects partial nitritation through pH since it concentration is calculated using pH (Anthonisen et al. 1976; Park and Bae 2009). According to (Anthonisen et al.

1976), when the pH is adjusted then the FA would change which alters the effluent nitrite and nitrate nitrogen as illustrated in. Anthonisen et al. (1976) also conducted studies and postulated predictive diagrams on the pH adjustment effect on Free Ammonia as well as the nitrifying bacteria. Free ammonia has been previously reported to have inhibitory effects on AOB activities. Free ammonia concentration of 25 mgNH3-N/L has been reported to decrease the oxidation rate of ammonia oxidizing bacteria by 40% for an enriched nitrosomonas culture (Balmelle et al. 1992). Jiang et al.

(2019) Also stated that long term exposure of AOB to FA have inhibitory effects on the cell morphology and hence the recoverability of the AOB culture. Wang and Dao found that the high FA level (5-40 mg/L) together with low DO concentration (< 0.13 mg/L) were responsible for the NOB suppression (In-Situ paper). (Anthonisen et al. 1976) had previously reported that inhibition of AOB by FA is in the range of 10-150 mg/L. An inhibitory value of NOB was observed to be 3.5 mg/L (Anthonisen et al.

1976). The inhibition by FA increases if AOB are simultaneously under total inorganic carbon limitation and total ammonium nitrogen starvation conditions (Torà et al. 2010).

Several studies have focused on evaluation this partial nitritation-anammox system in a single reactor, but these studies have revealed that is extremely difficult to monitor and control these processes in a single reactors. Therefore to overcome this problem, these processes should be evaluated on separate reactors until stability of the reactor operation is established. Following that, this study was conducted to evaluate and determine optimum conditions of DO, pH, and FA concentration when used as key conditions for partial nitritation stability.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

ASPEN PLUS SIMULATION OF BIOMASS PYROLYSIS USING MODEL COMPONENTS AT DIFFERENT TEMPERATURES Brendon Trollip, Ryan Merckel University of Pretoria, Pretoria, South Africa

Abstract Simulations of biomass pyrolysis published in literature exhibit issues in their reproducibility and replicability, where these are (i) erroneously presented (e.g., incorrect reaction rate variables and/or nonsensical model compounds are used) [1], (ii) overly complicated [2,3], and/or (iii) too vague [4]. An alternative method that is low in complexity, easily reproducible, and offers high accuracy is presented. This method is primarily intended for the estimation of the overall distribution of the product streams. The simulation employs the RStoic reactor unit operation available with the Aspen Plus® software package rather than the preferred Gibbs reactor unit operation. It was found that the Gibbs reactor unit operation lacks the necessary thermodynamic properties and required a library of compounds typical of biomass pyrolysis reactions. The method procedure inputs one model compound for each of the major biomass constituents of cellulose (D-glucopyranose), hemicellulose (D-xylose), and lignin (2-methoxyphenol). At least five compounds are used to simulate the pyrolysis oil products derived from the pyrolysis of cellulose, hemicellulose, and lignin, respectively, at 7 consecutive events at temperature intervals of 50 °C from 400 °C to 700 °C. Biochar was modelled as graphite (where it was necessary to treat this as a solid compound in Aspen Plus®), while synthesis gas was assumed to comprise solely of non-condensable gases (NGC’s), namely CO, CO2, and CH4.

Hydrogen of between 1 % and 2 % was additionally required to close the mass balance and ensure an error-free simulation. It was assumed that products would be more or less morphologically reminiscent of their parent structure such that only a small number of model compounds would be necessary. A total of 26 model components were used across the temperature range for pyrolysis oil.

References [1] Jaroenkhasemmeesuk C, Tippayawong N, Ingham DB, Pourkashanian M. Process modelling and simulation of fast pyrolysis plant of lignocellulosic biomass using improved chemical kinetics in Aspen Plus®. Chem Eng Trans. 2020;78:73–8.

[2] Peters Jens F., Iribarren Diego DJ. Predictive Pyrolysis Process Modelling in Aspen Plus®. An ASABE Meet Present. 2015;28935(July):2–2.

[3] Lestinsky P, Palit A. Wood Pyrolysis Using Aspen Plus Simulation and Industrially Applicable Model. Geosci Eng. 2016;62(1):11–6.

[4] Xianjun X, Zongkang S, Peiyong M, Jin Y, Zhaobin W. Establishment of Three Components of Biomass Pyrolysis Yield Model. Phys Procedia [Internet]. 2015;66:293–6. Available from: http://dx.doi.org/10.1016/j.egypro.2015.02.061

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ENERGY METRICS APPLIED TO BIOETHANOL PRODUCTION FROM SUGARCANE Panayiotis Ladas, Gabriela Steenekamp, Juvé Scheepers, Ryan Merckel University of Pretoria, Pretoria, South Africa

Abstract In South Africa, approximately 20-22 million ton of sugarcane is harvested from approximately 430 000 ha per annum [1]. The sugarcane industry has experienced a shift from producing sugarcane for sugar to the production of sugarcane for energy with the development of ethanol and cogeneration plants. This shift has justified the importance for the determination of the overall recovery of energy in the bioethanol product from the sugarcane feedstock with the use of energy metrics.

The process of bioethanol production from sugarcane encompasses a combination and integration of both first generation (1G) and second generation (2G) bioethanol production to ensure economic feasibility [2]. Along with the units of production, the cultivation process was also considered.

The energy metrics of the production of bioethanol from whole sugarcane was evaluated. These metrics included the energy efficiency, energy yield, mass yield, and the change of the energy quality of the energy carrying components using a method proposed by Merckel, 2020 [3]. An initial study applied these tools to the valorisation of sugarcane. However, it was found that the available information was insufficient where erroneous results arose. For example, the overall energy efficiency of 511 % was calculated on a wet basis. The initial study failed to consider various aspects of the process, such as: heat losses; the water fractions of each stream; the electricity required for the steam explosion pre-treatment and enzymatic hydrolysis unit operation; the energy required for pesticide production; and the effects of cogeneration from waste products. The current work expands on the application of these tools on case studies to provide a more holistic description of the energy efficiency associated with bioethanol production.

References [1] E. Meyer and L. J. Fenwick, “Manual sugarcane cutter performances in the southern Africa region,” Proc. South African Sugar Technol. Assoc., pp. 150–157, 2003.

[2] S. Macrelli, M. Galbe, and O. Wallberg, “Effects of production and market factors on ethanol profitability for an integrated first and second generation ethanol plant using the whole sugarcane as feedstock,” Biotechnol. Biofuels, vol. 7, no. 1, pp. 1–16, 2014, doi: 10.1186/1754-6834-7-26.

[3] R. D. Merckel, “Energy metrics juxtaposed with mass yield metrics” Renewable Energy, vol.

159, no. 2020, pp. 371-379, 2019.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid Ahmed Ridaa Kader, Ryan Merckel, Hasan Kalla University of Pretoria, Pretoria, South Africa

Abstract The half reactions of redox reactions are shown to have distinct energetic characteristics with reduction half reactions being exothermic and oxidation half reactions being endothermic. This is achieved through a quantum field theory (QFT) approach taken by way of the apportionment of energy to atoms of oxidation-reduction (redox) reactions which yields a succinct tool with which to predict and analyse their energetics based on atom involvement and molecular arrangement.

Hydrocarbonaceous compounds, especially biomass and its derivatives of biodiesel, bioethanol, methane, etc., are found to be significantly better suited to energy storage in terms of energy density.

Low-oxygen or oxygen-deplete compounds in particular are well-known to exhibit high energy densities. For instance, the average alkane storage capacity of 49.60 MJ kg-1 is far superior to that of the top-performing rechargeable cell, namely the lithium-ion cell (9.61 MJ kg-1). In the present method, referred to as the Electronegativity Apportionment Method, it is demonstrated that energy storage phenomena relate directly to electrostatic potential experienced by a given atom. It is observed that the conventional interpretation of redox reactions using oxidation numbers and halfcell analyses is not suitable for describing energy transformations of atomic species and that the consideration of the electronegativity of the species, by way of the Electronegativity Apportionment Method, is an appropriate substitute. That biomass-based energy storage systems (i.e., fuels that comprise of hydrocarbonaceous constituents and rely on combustion in an oxygen atmosphere) are superior when compared to other commercially available energy storage technologies is a major consequence of this research.

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23 Synergistic co-conversion of biomass and biogas to hydrogen – Performance Targets and Simulation Analysis.

Samukeliso Dube, Baraka C. Sempuga, Mahluli Moyo, Liu Xinying UNISA, Florida, South Africa

Abstract In this work, a holistic view of the co-conversion of biomass and biogas to hydrogen is theoretically explored to identify the attainable region and feasible targets in terms of material and energy balances. The role of carbon to hydrogen or oxygen ratio in the feed on the product spectrum and on the energy requirement is systematically explored. The carbon and hydrogen efficiencies increase with an increase in the ratio of biogas to biomass (1/rbm). As 1/rbm increases, the H2/CO ratio in the products increases. From 1/rbm of 0 to 1, the H2/CO ratio < 1.5, thus not suitable for Fischer Tropsch (FT) synthesis and char production. For higher 1/rbm ratios the carbon efficiency increases as the H2/CO ratios become > 1.5 thus good for synthesis reactions like FT. As the H2/CO ratio exceeds 1, 100% carbon efficiency is achieved as all the biomass and biogas C is converted into FT products.

Increasing the ratio of CO2 in the biogas decreases the hydrogen and carbon efficiencies of the system.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Biogas valorization to liquid fuels: Modelling and setting up targets Selusiwe Ncube, Baraka Sempuga, Xinying Liu, Mahluli Moyo University of South Africa, Florida, South Africa

Abstract Biogas has piqued interest in the energy sector as it poses as an attractive resource amid a world economy that is in a race against energy resources. This abstract presents an overview of the use of biogas in the single and co-production of various fuel intermediates, namely, methanol, ethanol, Dimethyl ether, and Fischer-Tropsch (FT) products to redress the crippled energy sector that is largely dependent on non-renewable resources. The feasibility of converting biogas to liquid fuels from the material and thermodynamic point of view is explored. A back-to-norm approach is exercised to explore the concept of the attainable region and targeting techniques which are applied to determine the optimum product distribution at the conceptual stage of the design process [1]. With the aid of MATLAB, we show that the precedence of co-producing FT fuels (CH2) with liquid fuels to the single production of FT fuels extends beyond contributing immensely to the octane value of gasoline. In particular, we exploit the ability of oxygenates to act as receptors to the oxygen in the feed materials that would otherwise be expended as undesirable CO or H2O products in the single production of FT fuels. We explore the feasibility of these options by benchmarking them against such performance indicators as the material, work and energy balance and the carbon and hydrogen efficiencies. We demonstrate that the optimal result can be achieved at a CH3OH: CH2 ratio of 10:90 at 74 % carbon efficiency and at a minimum carbon dioxide feed rate of 0.499 mol/mol_CH4. Most importantly, we establish that the process of co-producing methanol and FT from biogas is work-neutral, hence, conserving the chemical potential.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

The importance of carbon structure in biochar as catalysts/supports for reforming tarry compounds.

Shu Zhang, Anjiang Gao, Shasha Liu, Yong Huang Nanjing Forestry University, Nanjing, China

Abstract As the sole renewable carbon resource on earth, biomass has great potential to replace fossil resources to obtain fuels and chemicals. The efficient utilization of biomass resource will play a key role in achieving the carbon neutrality by 2060 in China. On one hand, the development of feasible gasification technologies to produce syngas (primarily H2 and CO) is considerably inhibited by the “tar issues”. The tar content in the product gas has to be extremely low in order to effectively use the gas in downstream, such as for synthesizing liquid fuels and generating electricity [1-2]. Biochars have been regarded as a great potential catalyst for reforming tarry compounds into light gases. On the other hand, the chemical compounds in bio-oil can be significantly affected and determined by the volatile-char interactions during the pyrolysis process, where the char actually acts as an in-situ generated catalyst [3-4]. Therefore, the catalytic performance of biochar is a key factor in affecting the final products of biomass pyrolysis and gasification. The char structure including matrix carbon structure and functional groups on char surface not only affects the reactivity of non-metal active sites but also largely dominate the role/fate of internally-existing and externally-added metal species [5-6].

This work is to fundamentally examine effects of carbon structure in char on the char’s activity in reforming tarry compounds. The results indicate that the tarry materials (e.g. benzyl phenyl ether, a volatile model compound) can be reformed into very different hydrocarbons by char catalysts with varying carbon structure.

References 1. Bridgwater A. The technical and economic feasibility of biomass gasification for power generation. Fuel. 1995; 74(5): 631-653.

2. Bhattacharya S, Siddique A M M R, Pham H-L. A study on wood gasification for low-tar gas production. Energy. 1999; 24(4): 285-296.

3. Shen Y. Chars as carbonaceous adsorbents/catalysts for tar elimination during biomass pyrolysis or gasification. Renewable and Sustainable Energy Reviews. 2015; 43: 281-295.

4. Cao J-P, Liu T-L, Ren J, Zhao X-Y, Wu Y, Wang J-X, Ren X-Y, Wei X-Y. Preparation and characterization of nickel loaded on resin char as tar reforming catalyst for biomass gasification. Journal of Analytical and Applied Pyrolysis. 2017;127: 82-90.

5. Huang Y, Gao Y, Zhou H, Sun H, Zhou J, Zhang S. Pyrolysis of palm kernel shell with internal recycling of heavy oil. Bioresource Technology. 2019; 272:77-82.

6. Buentello-Montoya D, Zhang X, Li J, Ranade V, Marques S, Geron M. Performance of biochar as a catalyst for tar steam reforming: Effect of the porous structure. Applied Energy. 2020; 259:114176.

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Production of phenol from co-pyrolysis of cellulose and sodium borohydride Gang Wu, Yuhui Wang, Yong Huang, Shu Zhang Nanjing Forestry University, Nanjing, China

Abstract Biomass resources are the sole carbon-containing renewable resources on the earth, which have high potential in the production of platform chemicals. Phenol, an important platform chemical, is generally considered to be derived from lignin conversion (1). In this study, production of phenol from co-pyrolysis of cellulose and sodium borohydride at different mass ratios and temperatures was investigated in detail. The results showed that even a small amount of sodium borohydride (cellulose: sodium borohydride = 10:1) could effectively promote the conversion of cellulose to phenol through series reactions of decarbonylation, decarboxylation, dehydration, condensation, and ring formation of the cellulose-derived levoglucosan and furans intermediates. As the mass ratio of cellulose: sodium borohydride decreased, the relative content of phenolic compounds in the liquid products significantly increased, which can be as high as 10.35% when the ratio of cellulose to sodium borohydride was 1:1.

Furthermore, the resulting solid product could be used as a B-doping carbon material, which was desired in many research fields (2-4). This study provides a novel method for high-efficient utilization of cellulose.

References [1] Schutyser W, Renders T, Van den Bosch S, Koelewijn SF, Beckham GT, Sels BF. Chemicals from lignin: an interplay of lignocellulose fractionation, depolymerisation, and upgrading. Chemical Society Reviews. 2018;47(3):852-908.

[2] Xia T, Zhu Y. Hierarchical B-doped carbon nanotube with enhanced electrochemical lithium storage. Microporous and Mesoporous Materials. 2019;284:276-82.

[3] Song B, Wang Q, Wang L, Lin J, Wei X, Murugadoss V, et al. Carbon nitride nanoplatelet photocatalysts heterostructured with B-doped carbon nanodots for enhanced photodegradation of organic pollutants. Journal of Colloid and Interface Science. 2020;559:124-33.

[4] Bhaumik A, Sachan R, Gupta S, Narayan J. Discovery of High-Temperature Superconductivity (Tc = 55 K) in B-Doped Q-Carbon. ACS Nano. 2017;11(12):11915-22.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Development of Castor oil jet fuel catalysed by bi-functional Ni-Zn metals on carbon support Sharron Ratshoshi, Diakanua Nkazi, Hembe Mukaya University of the Witwatersrand, Johannesburg, South Africa

Abstract Economic uncertainties and environmental issues related to petroleum fuels have led to an intensified research towards the production of biofuels. The availability and abundance of process feedstock materials are required for sustainable production of biofuel and capacity demand. The strategical agriculture and harvest plan of Castor make it the current potential source of environmentally friendly fuel. An investigation was conducted on hydrocracking of castor oil in the presence of bi-functional catalysts Ni-Zn/NCB (Nickel-Zinc/Nano Carbon Base) of which were prepared by the Co-impregnation and Sequential impregnation methods. The catalysts with metals Ni: Zn were in ratios of 2:1(coimpregnation) and 1:3(sequential impregnation) respectively. Characterization of the catalysts was performed by TGA, BET, SEM, TEM, XRD, and FTIR for understanding the performance of the catalysts during reactions. The catalysts morphologies revealed that the catalysts had formed agglomerates and they were thermally stable between temperatures of 300 and 600◦C. A series of experiments were conducted to investigate the effect that different reaction parameters namely Temperature, Reaction time and Catalyst loading have on the production of bio-jet. The GC-MS was used to characterize the produced biofuels and were grouped into bio-gasoline (C5-C11), bio-jet (C12-C15), Biodiesel (C16C18) based on their carbon ranges. From the results, it was observed that co- and sequential impregnation methods had the highest bio-jet selectivity of 65,23% and 72,33% respectively. These high bio-jet selectivities were both achieved with a catalyst loading of 100mg, a temperature of 250◦C, and a reaction time of 2.5 hours. The catalyst's preparation methods and characteristics influenced the bio-jet production yield.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Anaerobic co-digestion of sewage sludge with sugar wastewater for biomethane production using Optimal design Jeremiah A Adedeji1, Maggie Chetty2, Amir H Mohammadi1 1

University of KwaZulu-Natal, Durban, South Africa. 2Durban University of Technology, Durban, South Africa

Abstract The use of sugar wastewater (SW) as co-substrate for the digestion of sewage sludge (SS) was investigated in this study as the use of food and agricultural wastes have been reported in past studies.

The effect of varying the mix-ratio of the substrates, as well as that of temperature on the yield of biomethane (mL CH4/g CODt) was evaluated to determine the optimum condition. An optimal combined design (OCD) and numerical optimization tool were used in setting up the design and optimization of the associated variables. With desirability of 80.4%, the optimum condition for the codigestion study was 1:1 for SS: SW and 29.7oC for a biomethane yield of 176.19 mL CH4/g CODt. Results obtained reveals that the addition of SW aids in increasing the yield of biomethane and the selected statistical tool could help in the prediction of the optimum conditions for the anaerobic co-digestion process.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Natural Sorbents from Amarula Wastes Biomass and their Activated Carbons for Sorption of Dibenzothiophene in Model Diesel Fuel Tsepiso Kabi, Yali Yao, Liu Xinying, Diane Hilderbrandt UNISA, JHB, South Africa

Abstract Diesel fuel contains organic sulphur compounds which when emitted to the atmosphere impact the environment negatively. On the other hand, there is a need to utilize renewable resources such as biomass as sorbents because they are economically feasible as compared to materials from non renewable resources. Therefore, this study investigates the use of natural sorbents from Amarula wastes biomass to reduce the content of dibenzothiophene in model diesel fuel using batch sorption method. The sorbents were processed to activated carbon (AC) using steam activation and then applied to diesel fuel. The percentage removal of dibenzothiophene from natural sorbents was up to 30 % whereas for processed sorbents it was above 60%. The structural properties were identified using BET technique which showed more improved surface area and pore sizes on processed sorbents. Further characterisation was done using FTIR, XRD and TGA. Kinetics and Isotherms models were applied to experimental results. Pseudo second order was found to be the best kinetic model for both natural sorbents and processed sorbents. Lungmuir isotherm was found to be the best fit on both the natural sorbents and the activated carbons

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Synthesis of carbon nanotubes over iron based metal organic frameworks (MIL88B & MIL101) Keaoleboga Mosupi1,2, Ashton Swartbooi1, Nqobile Mthembu1,2 1

Council of scientific and industrial research, Pretoria, South Africa. 2University of Pretoria, Pretoria, South Africa

Abstract Multiwalled carbon nanotubes (MWCNTs) were prepared via catalytic chemical vapour deposition of biogas at 900 ºC over iron precipitated from acid mine drainage (AMD) as well as iron-based metal organic frameworks (MOFs), MIL88B (1) & MIL101 (2) derived from AMD. For comparison with known processes, ethylene gas was used to determine the optimal conditions. The use of AMD affords a green synthesis route for the synthesis of CNTs. The diameter of the CNTs is controlled by the catalyst size.(3) Thermal decomposition of organic linkers of the MOFs results in tip growth mechanism of CNTs (weak interaction between the substrate and the active metal). The morphological structure of the CNTs was examined using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Raman spectroscopy

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Catalytic Valorisation of Sugarcane Bagasse to Energy Carriers Ifeanyi Michael Smarte Anekwe1, Sherif Ishola Mustapha2, Yusuf Makarfi Isa1 1

University of the Witwatersrand, Johannesburg, South Africa. 2Durban University of Technology, Durban, South Africa

Abstract Sustainable processes have continued to be of interest to both the academia and industries. The sugar industry in this regard has explored the potentials of using sugar cane bagasse as a fuel in the sugar cane industry. In addition to its fuel potentials, bagasse has potentials of being converted to chemical compounds that could serve as both chemicals and energy carriers.

In this work, we investigated the potentials of adding value to sugarcane bagasse by catalytic and noncatalytic hydrothermal liquefaction and pyrolysis. HZSM-5 was used as catalyst for both the hydrothermal liquefaction and pyrolysis processes.

Experiments were conducted in a batch HTL reactor under various operating conditions to determine the effect on product distribution. The operating temperature (220 – 373 oC) and heating time (30 – 60 min) were altered while the ZSM-5 catalyst, reactor volume loading and feedstock to water ratio remained fixed. The pyrolysis experiments were carried out using a stainless steel reactor. For the non-catalytic pyrolysis tests, 1g each of the dried bagasse sample was charged into the reactor while the catalytic tests used a mix of catalyst with bagasse sample (0.1:1 g/g). The pyrolysis was carried out at temperatures of 400 °C, 450 °C and 500 °C. The effect of catalyst to biomass on the product yield was also investigated at a temperature of 400 °C by varying catalyst to biomass ratio (0.1:1 g/g), (0.25:1 g/g) and (0.5:1 g/g) .

The results showed that various compounds were obtained as the hydrothermal conditions were varied. Interestingly, the hydrocarbons were relatively lower in concentration when compared to the substituted hydrocarbons. The highest amount of hydrocarbons (a little over 6 wt.%) was obtained when the bagasse was hydrothermally converted using a catalyst at 300 °C for 45 minutes. Esters accounted for about 80 wt. % when the process was carried out at 373 °C and 45 minutes in the presence of ZSM-5, this was more than double the amount obtained when the same conditions were used in the absence of a catalyst.

The findings from the pyrolysis experiments showed that both the temperatures and catalysts affected the yield of the pyrolytic products The HHV of the pyrolytic bio oil was highest when the catalyst to bagasse ratio was 1:4.

From the work conducted, it is shown that products with higher heating values than that of dry bagasse can be produced by thermos chemical conversion of bagasse. It was also observed that HZSM5 could dictate the product distribution during the hydrothermal liquefaction as well as pyrolysis of sugarcane bagasse.

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Biogas as a feedstock for renewable hydrogen and carbon generation-a circular approach.

Ashton Swartbooi, Nicholas Musyoka CSIR, Pretoria, South Africa

Abstract Hydrogen generation is receiving increased global attention, with an international drive towards a hydrogen economy (1,2). Current industrial methods of hydrogen production include the use of fossil fuels through the steam reforming of natural gas. Upgraded biogas (biomethane) is a renewable, carbon neutral energy source that can potentially be used as a substitute for natural gas in hydrogen production (3). Hydrogen production by biomethane decomposition can pave the way for the development of a low-carbon hydrogen economy.

Carbon materials are also promising materials in the field of material science, due to their extensive usage in various applications (4). Various carbon materials can be obtained during the catalytic decomposition (CDM) of biomethane (activated carbon, carbon black, graphite, carbon nanotubes, carbon nanofibers, etc.), and considerable efforts have been made in the field to develop optimised catalysts for the CDM process (3).

A circular approach towards biogas utilisation for renewable hydrogen and carbon materials generation will be presented. Hydrogen generated can be utilised in a fuel cell system, to generate clean energy, while the produced carbon materials can be re-used as catalysts and/or catalyst supports, or towards the biogas upgrading step.

References 1.

Nazir H, Louis C, Jose S, Prakash J, Muthuswamy N, Buan MEM, et al. Is the H2 economy realizable in the foreseeable future? Part I: H2 production methods. Int J Hydrogen Energy. 2020 May 18;45(27):13777–88.

2.

Quarton CJ, Samsatli S. The value of hydrogen and carbon capture, storage and utilisation in decarbonising energy: Insights from integrated value chain optimisation. Appl Energy. 2020 Jan 1;257.

3.

Zhang J, Li X, Chen H, Qi M, Zhang G, Hu H, et al. Hydrogen production by catalytic methane decomposition: Carbon materials as catalysts or catalyst supports. Int J Hydrogen Energy. 2017 Aug 3;42(31):19755–75.

4.

Pudukudy M, Yaakob Z, Takriff MS. Methane decomposition into COx free hydrogen and multiwalled carbon nanotubes over ceria, zirconia and lanthana supported nickel catalysts prepared via a facile solid state citrate fusion method. Energy Convers Manag. 2016 Oct 15;126:302–15.

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Evaluation of in-situ and ex-situ hybridization study in the optimised transesterification of waste and pure vegetable oils Anietie Etim1, Paul Musonge2, Andrew Eloka-Eboka3 1

Institute of System Science, Durban University of Technology, Durban, South Africa. 2Institute of System Science, Durban University of Technology, and Faculty of Engineering, Mangosuthu University of Technology, Durban, South Africa. 3School of Chemical and Minerals Engineering, North West University, Potchefstroom, South Africa

Abstract Feedstock hybridization is an effective approach in obtaining the required and improved fuel properties and in removing the hurdles of non-availability of the traditional raw materials for biodiesel production. This study explored the optimized parametric transesterification of biodiesel production from used frying oil and linseed oil using potassium salt-based compounds derived from banana peels.

Fractions of the oils were analysed and hybridized in the ratio of 50:50, 30:70, 70:30 to obtain bihybrid oils and then trans-esterified using the optimal conditions to obtain hybridized biodiesel fuel – in-situ hybridization. The same ratio of co-mingling was also applied to the already produced single oil biodiesel to obtain bi-hybridized biodiesel fuels – ex-situ hybridization. The biodiesel obtained from the two hybridization process pathways were analysed for fuel properties and compared with the standards. The optimal condition established was methanol-to-oil ratio 10:1, catalyst amount 3.5 wt%, the reaction time of 60 min and a constant temperature of 65oC, the maximum biodiesel yield achieved for single and hybrid oil were within the range of 94-97 %. The fuel properties: density, viscosity, acid value, iodine value, cetane number and the calorific value obtained from the process of hybridization were well situated within the international and SANS standards. In some cases, the properties obtained via the ex-situ hybridization approach were much improved than those of in-situ hybridization. The study shows that the application of the two hybridization approaches is appropriate for biodiesel development as a parallel process.

Keywords: Biodiesel, in-situ and ex-situ hybridization, heterogeneous transesterification, optimization, hybrids.

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Rethinking municipal waste management using a thermochemical approach.

Sanette Marx, John R Bunt, Roelf J Venter, LC Muller, Jonedine B Van der Merwe, Christine T Dewah North-West University, Potchefstroom, South Africa

Abstract According to the South African State of Waste Report (1), 54.2x106 ton of general landfill waste was generated in South Africa in 2017 of which 38.6% was recycled. Organic waste comprised 56.3 % of all organic waste and only 12.1x106 tons were recycled. In compliance with the 2011 National Waste Management Strategy (NWMS) (2) municipalities and industry are obligated to improve waste management by reducing the amount of organic waste on landfill sites. The Western Cape provincial government has implemented a plan to divert 50% and 100% of organic waste from landfill by 2022 and 2027 respectively (3). On a national scale about 21x106 ton of organic municipal solid waste will be available for use in waste-to-energy applications. Furthermore, the primary settling step used in South African wastewater treatment plants produced about 6.3x105 ton of primary sewage sludge in 384 plants of which 5.38x105 tons were landfilled (1). In 2017, only 60 of the 384 plants produced clean water (4) according to the standard for safe drinking water (5) with 52% of sewage and wastewater ending up and accumulating in in rivers and dams.

In this paper, we present a viable solution that uses both organic municipal waste and sewage sludge as feedstock to a waste-based bio-refinery. Hydrothermal liquefaction (HTL) is used as main processing unit to produce bio-crude oil, hydrochar, process gas and an aqueous product. All reported product yields and quality is based on real-time experimental data. Implemented nationwide at all 384 municipal wastewater treatment plants and landfill sites, it is estimated that 1.3 GL of biodiesel, 3.7 Mton of GreenCoal, 9.4x108 m3 of pure CO2 gas, 4.35 GWh of biogas electricity, 125.6 kton of platform chemicals, 217 kton of polyurethane foam and 11.9 GL of clean water can be produced from the HTL products. Some of the hydrochar product (0.004 mass %) was used as an adsorbent for recovery of the alkali and alkali earth metals and phenolic platform chemicals present in the aqueous product. The carbon and nitrogen mass balance recovery of the HTL unit was 91.2 % and 76.9 %respectively. Furthermore, with an energy consumption rate of 0.142, the HTL unit will require 2.81 GWh to produce the products with a total average bulk market value of R 63.4 billion. The methane in the process biogas thus provides enough energy for the HTL unit be run independently from the electricity grid. A full techno-economic study and LCA analysis is however still required to assess economic feasibility of the full production chain and the sustainability of the process at municipal scale. The proposed bio-refinery is an elegant solution for solid and liquid municipal waste reduction while contributing towards a circular economy and supporting the UN sustainable development goals 6 (Clean water and sanitation), 7 (Affordable and clean energy) and 11 (Sustainable cities and communities).

References [1] Department of Environmental Affairs. State of Waste Report South Africa - Second draft report.

2018.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid [2] Department of Environment Forestry and Fisheries. National Waste Management Strategy [Internet].

Waste Management Document.

2011.

Available from: https://www.environment.gov.za/sites/default/files/docs/nationalwaste_management_strategy.pdf [3] Venter M. DEADP-organic-waste-landfill-ban-letter-July-2018. 2018.

[4] Herbig FJW. Talking dirty - effluent and sewage irreverence in South Africa: A conservation crime perspective.

Cogent Soc Sci [Internet].

2019;5(1).

Available from: https://doi.org/10.1080/23311886.2019.1701359 [5] Galal-Gorchev H. WHO guidelines for drinking-water quality. Water Supply. 1993;11(3–4):1–16.

[6] Wu D, Peng X, Li L, Yang P, Peng Y, Liu H, et al. Commercial biogas plants: Review on operational parameters and guide for performance optimization. Fuel. 2021;303(174).

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Hydrothermal liquefaction of lignocellulosic biomass into biofuels and its utilisation in energy Tshimangadzo Makhado University of the western cape, Cape Town, South Africa

Abstract The global dependence on non-renewable fossil fuels to meet energy’s need cannot be sustained for a long time and it is already evident in the instability of fuel prices in recent times and the severe environmental impacts like climate change [1]. It is important that the world switches over to renewable and sustainable energy alternatives that mimic the natural geological process thought to be involved in the production of fossil fuels. Lignocellulosic biomass has received great interest because they are abundant, renewable, and environmentally friendly [2].Furthermore, they are obtainable from different sectors including agriculture and food processing, among others.The wide variety of their origin also reflects on the nature of this biomass. Most biomass is obtained with a certain amount of moisture. While this moisture could be removed, the removal process may result in extra feed treatment costs involving drying [3]. It is therefore worth investigating processes that may not require the step of moisture removal while converting biomass to fuels and petrochemicals.

In this work, the potentials of agricultural and food wastes as feedstock in hydrothermal liquefaction will be investigated. The choice of materials stems from the need to focus on second generation biofuel production.The process will be conducted in a hydrothermal reactor while varying the ratios of the various biomass to be investigated. A high temperature, high pressure reactor will be used for all experiments. Moreover, crystalline structure and surface morphology of different feedstock and catalyst will be investigated using XRD, SEM and TEM characterization while functional groups will be characterised using FTIR Spectrometry and Gas chromatography mass spectrometry.

In a typical experiment, the reactor will be charged with the feedstock containing the desired amount of moisture.The reactor will be heated to a desired temperature and kept for a desired reaction time.

Alongside the feed composition, the effect of process parameters such temperature and time on the yield and distribution of products will be investigated. After an experimental run, gaseous products will be vented while solid and liquid products will be collected from the reactor. The liquid hydrocarbons produced will be separated form solids using the appropriate washing solvents. The reaction products will be characterised using gas chromatography. The calorific values of the products obtained will be investigated with a view to harnessing their energy potentials. Structural properties related with functional groups of biofuels will be identified using FTIR Spectrometry. Thermal gravimetric analysis will be used to gain insight into the thermal stability of the feedstock. The project is focused on combating the challenges of Energy while adding values to wastes from Agricultural activities and the food processing.

References.

1. Zhang Y. Biofuels from agricultural waste and by-products. 201-203. ISBN 9780813802527 37 | P a g e

Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid 2. Bikash K et all. 2018. Recent trends in the pre-treatment of lignocellulosic biomass for value added products. Vol 6.1-2 3. Jing G. 2012. Hydrothermal conversion of lignocellulosic biomass to biofuels.

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Cellobiohydrolase I assisted refining: Impact on energy consumption and pulp quality Ntokozo Makubo North-west university, Potchefstroom, South Africa. Sappi technology centre, Pretoria, South Africa

Abstract Papermaking is an energy-intensive process, with mechanical pulp refining accounting for 30% of the total electrical energy consumption during papermaking [1]. Presently with the significant economic and environmental concerns, improving energy efficiency and minimising the environmental implications of paper manufacturing is critical. Biotechnological pulp treatments have demonstrated a high potential for lowering energy consumption as well as improving the fibre development [2,3].

The benefits of enzymes application include energy savings, very modest adjustments in the existing industrial processes, environmentally friendly treatment and lastly improvement in the fibre and pulp quality. Presently, the most investigated enzymes for fibre modification are cellulases [4,5,6].

A cellulase, Cellobiohydrolase I (CBH I) was investigated as a refining enzyme at various specific edge load (SEL) and refiner plate designs. Five bijective runs were conducted with the addition of the enzyme, CBH I. A control sample in the absence of the enzyme was performed using the reference refining conditions (Table 1). The enzyme was added during the repulping step and a 12” single-disc pilot refiner was used to simulate industrial conditions. After low consistency refining, the results obtained for bleached hardwood kraft pulp (BHKP) were analysed at a desired drainage rate of 350 ml. Subsequently, a customised bijective modelling software was used to find the optimum refining parameters for the BHKP to reach the targeted drainage rate.

At the drainage rate of interest, the CBH I treated pulp improved the strength properties except for tear strength and decreased the required specific refining energy demand by 33% compared to the untreated pulp. The BHKP responded better to the low intensity refining (SEL-), thus showed an improvement in strength development. In contrast the increasing the intensity (SEL+) resulted in fibre quality deterioration. The GC run (smaller bar widths and grooves plate design) led to the highest strength development, but also required the most refining energy. In comparison the GA run (bigger bar angle plate design) led to more fibre cutting than fibrillation. The optimum refining parameters generated by the modelling software were validated by refining the pulp three times under optimal energy and intensity. A repeatability test conducted using one-way ANOVA indicated a statistically insignificant difference between the three runs at a 95% confidence level.

In conclusion, CBH I enzyme has the potential to transform the refining process towards a more environmentally friendly, cost effective and efficient operation compared to the conventional method.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid References [1] Lecourt, M., Meyer, V., Sigoillot, J.-C. & Petit-Conil, M. 2010a. Energy reduction of refining by cellulases. Holzforschung, 64(4).

[2] Lecourt, M., Sigoillot, J.-C. & Petit-Conil, M. 2010b. Cellulase-assisted refining of chemical pulps: Impact of enzymatic charge and refining intensity on energy consumption and pulp quality. Process Biochemistry, 45(8):1274-1278.

[3] Znidarsic-Plazl, P., Rutar, V. & Ravnjakc, D. 2009. The Effect of Enzymatic Treatments of Pulps on Fiber and Paper Properties. Chemical and biochemical engineering, 23(4):497–506.

Pathak, P., Kaur, P. & Bhardwaj, N.K. 2017. Microbial enzymes for pulp and paper industry: Prospects and Developments. Microbial Biotechnology:163-225.

[4] Singh, R. & Bhardwaj, N.K. 2010. Enzymatic refining of pulps: An Overview. Indian Pulp & Paper Technical Association, 22:109-116.

[5] Tripathi, S., Sharma , N., Mishra, O.P., Bajpai, P. & Bajpa, i.P.K. 2008. Enzymatic Refining of Chemical Pulp. IPPTA, 20(3):129-132.

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Effect of reaction conditions on bio-oil produced from sodium lignosulphonate Danel Bartlett, Roelf Venter, Sanette Marx North-West University, Potchefstroom, South Africa

Abstract Due to years of research, it’s known that the overexploitation of the world’s main energy source, fossil fuels, is not only depleting resources, but it is also causing environmental destruction, threatening the health of human beings, and could threaten the economic stability worldwide. The only solution is to find alternative energy resources that can reduce the strain on current fossil energy systems. One alternative energy resource is biodiesel (1). It is a cleaner energy source that is produced from different renewable sources and methods. One of the potential sources is non-edible lignocellulosic biomass (2). Lignocellulosic materials are inexpensive and abundant natural polymers (200Gt produced worldwide per annum (3)) (4). One of the lignocellulosic biomass’ main constituents, is lignin, a heterogeneous, aromatic biopolymer that is a waste product from paper pulping processes and is mainly available in the form of lignosulphonates that account for 90 % of all available lignin and is a severely under-utilized resource. Producing lignin-derived bio-oil for renewable fuel production will have significant economic and environmental advantages. Bio-oil may be more eco-friendly, but it’s still a fairly new technology and so there are some challenges when competing with the current fossil fuels (5, 6). Bio-oil is more acidic with higher oxygen, moisture, and ash content and lower hydrogen and carbon content, causing lower calorific values and thermal instability (1). These issues can be resolved by upgrading the bio-oil through several conversion methods. One possibility is hydrothermal liquefaction (HTL) with hydrodeoxygenation to improve the molecular composition and thus improving the properties (2). Using alkali catalysts like sodium hydroxide could help the acidic nature of bio-oil (7). In this study, HTL was used to investigate the influence of process conditions such as reaction temperature (240-320˚C), residence time (20-80 min), and catalyst loading (2-6 mass %) on bio-oil produced from sodium lignosulphonate in an ethanol solvent with an alkali catalyst (sodium hydroxide). The bio-oils were characterized with FT-IR, elemental, calorific values, GPC, GC-MS, and NMR. This study found that the three reaction parameters had an effect on the bio-oil’s yield and quality and a combined effect was also observed. The combined effect was measured with the use of a severity factor. Residence time will have a larger effect on bio-oil yield when the temperature is low, but as the reaction temperature is increased, residence time will be less influential. The results showed that to improve the yield of bio-oil, more catalyst would be advantages combined with low temperatures and longer times since it would increase the bio-oil yield at the expense of the gas. For improved quality higher temperatures are required combined with lower catalyst loadings and shorter residence times. Longer times may provide deeper depolymerization, but will promote repolymerization. The shorter times will produce a bio-oil with a larger diesel fraction (±77 mass %), smaller molecular weights and less heavy compounds, with a high carbon recovery. It was noted that should the process parameters require different conditions, similar results can be obtained with the severity factors.

References

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid 1.

Sánchez F, Mateos A, García Martín J. Biodiesel and other value-added products from bio-oil obtained from agrifood waste. Processes. 2021;9:797.

2.

Ahorsu R, Medina F, Constanti M. Significance and Challenges of Biomass as a Suitable Feedstock for Bioenergy and Biochemical Production: A Review. Energies. 2018;11:3366.

3.

Iroba K, Tabil L, Sokhansanj S, Dumonceaux T. Pretreatment and fractionation of barley straw using steam explosion at low severity factor. Biomass and Bioenergy. 2014;66.

4.

Ramakoti B, Dhanagopal H, Deepa K, Rajesh M, Ramaswamy S, Tamilarasan K. Solvent fractionation of organosolv lignin to improve lignin homogeneity: Structural characterization.

Bioresource Technology Reports. 2019;7:100293.

5.

Aro T, Fatehi P. Production and Application of Lignosulfonates and Sulfonated Lignin.

ChemSusChem. 2017;10(9):1861-77.

6.

Lu Y, Lu Y-C, Hu H-Q, Xie F-J, Wei X-Y, Fan X. Structural Characterization of Lignin and Its Degradation Products with Spectroscopic Methods. Journal of Spectroscopy. 2017;2017:8951658.

7.

Stedile T, Beims RF, Ender L, Scharf DR, Simionatto EL, Meier HF, et al. EVALUATION OF DISTILLATION CURVES FOR BIO-OIL OBTAINED FROM THERMAL CRACKING OF WASTE COOKING OIL. Brazilian Journal of Chemical Engineering. 2019;36:573-85.

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Cogasification of biomass and plastic waste : A mini review ZVANAKA MAZHANDU1, EDISON MUZENDA2,1, MOHAMED BELAID1, TRUST NHUBU1 1

University of Johannesburg, Johannesburg, South Africa. 2Botswana International University of Science and Technology, Palapye, Botswana

Abstract 1.0 INTRODUCTION The interest in gasification has been growing globally due to the need for alternative energy recovery technologies and cleaner energy sources which do not negatively impact the environment. Biomass and post-consumer plastic wastes are among some of the alternative energy sources to coal that have been widely researched together with gasification technology [1]. In gasification; a thermochemical process, carbon-based compounds are converted into a gas referred to as synthesis gas which mainly consists of carbon monoxide (CO), hydrogen (H2), methane (CH4), carbon dioxide (CO2). Synthesis gas can be used in the production of electricity or as a feedstock in other chemical processes. Although statistics for plastic waste in South Africa are well documented through Recycling surveys done by Plastics South Africa, a detailed inventory on the amount of available wood waste in the country is lacking. In Cape Town, 760 000 tonnes/year of treated wood waste has been reported [2]. Woody biomass, which is biomass produced from trees can be categorised into 3 groups, namely [3]: (1) wood from forests and plantations, (2) wastes and residues from industries that process wood, (3) postconsumer use wood. The renewable nature of this type of biomass; as forests can be regrown (afforestation), points to the sustainability of energy recovery from woody biomass.

The aim of this paper is therefore, to determine the effect of cogasifying woody biomass and plastic waste by systematically reviewing the existing body of literature that exists, determine suitable gasification technology that can be used, determine the operating conditions for the cogasification process and determine the various cogasification media that can be used.

Peer-reviewed literature was accessed from various academic databases including Web of Science, Google Scholar and Scopus. Key words/phrases used individually and in combination were; gasification of plastic waste, gasification of biomass, cogasification of biomass, gasification technology, cogasification operating conditions, life cycle analyses. Only review and research articles from 2000 to 2021 written in English were considered.

The key findings are that, plastic waste in cogasification with biomass; increases calorific value of the gas, increases reactivity of the plastic/wood mixture and increases the yield of gas while biomass presence in plastic waste gasification reduces difficulties experienced when feeding the plastic waste into the gasifier as it rapidly softens after contact with heat. Chemically treated woody biomass may have significantly higher negative environmental impacts compared to gasification of polyolefins.

Energy requirements maybe higher with woody biomass gasification.

There exists an untapped opportunity for South Africa in the field of cogasification of plastic wastes and woody biomass in waste management. However, the plastic to wood waste ratio in the feed is also crucial to determine.

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REFERENCES [1] F. Pinto, C. Franco, R. N. André, M. Miranda, I. Gulyurtlu, and I. Cabrita, “Co-gasification study of biomass mixed with plastic wastes,” Fuel, vol. 81, no. 3, pp. 291–297, 2002, doi: 10.1016/S00162361(01)00164-8.

[2] L. Basson, S. Bronkhorst, and N. Fordyce, “Waste-2018 Market Intelligence Report-18,” 2018, [Online]. Available: www.greencape.co.za.

[3] L. Mtshali, M. Dlamini, and N. . Kohler, “The Opportunities and Challenges of Wood Waste Biomass and a Case Study on Biofuels in South Africa,” Inst. Waste Manag. South. Africa, no. October, pp. 350–355, 2018.

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Optimization of Organic Loading Rate Using Biomethane Potential Test Dimakatso Mampane, Anthony Matheri University of Johannesburg, Johannesburg, South Africa

Abstract The high rate of uncontrolled waste has turned out to be detrimental to the health of living organisms, hence the establishment of the bio-waste management project; such projects aims at establishing a circular economy for the organic waste generated with which happens to be costly when no prior assessment of the expected products are made. This study investigated the validity of kinetic models in predicting maximum biogas yield with an increase in the organic loading rate (OLR) and retention time of Cellulose, Activated sludge and Brewery waste as the studied biomasses. The bio-methane potential (BMP) tests were performed on a Bioprocess control AMPTS II digestion system to obtain produced biogas data to be used to be used as controls by the kinetic models to predict the production of biogas. The kinetic models were the modified Gompertz, modified Logistics and modified Richardson and were used to derive the kinetic constant parameters which were used to assess the effectiveness of the correlations brought about by the studied models for a cumulative biogas production time of 60 days. The digestion process was studied at a Mesophilic temperature condition of 37 and a pH range of 6.5-7. The carbon/ nitrogen ratio of all the studied substrates appeared to be within the required range of 15-30, which proved their adequate ability to provide stability to the bacteria used in enhancing the anaerobic digestion process; Cellulose had a ratio of 30.00, brewery 21.607 and the sewage waste 15.569. The results indicated that there was better correlation for the Gompertz and the Richard models as compared to the logistics model. The biogas production rate increased with the OLR.

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Impact of life cycle assessment for municipal plastic waste treatment in South Africa OLUSEGUN OLAGUNJU, Sammy Kiambi DURBAN UNIVERSITY OF TECHNOLOGY, DURBAN, South Africa

Abstract Municipal Plastic Wastes (MPW) can have a number of negative effects on the environment and this is causing a growing concern which requires urgent intervention. Addressing these environmental challenges by proffering alternative end-of-life (EOL) techniques for MPW treatment is thus critical for designing and implementing effective long-term remedies. In this study, the environmental implications of several MPW treatment technologies were assessed using life cycle assessment (LCA).

Our focus was on four potential waste treatment scenarios for MPW: waste disposal via landfill, waste incineration, waste regeneration, and reusability of recycled waste. The findings show that recycling has a greater benefit over landfilling and incineration methods.

The most important environmental benefit comes from the recycling of plastics, which may serve as good source materials for environmentally friendly products. Following a holistic evaluation, five major factors that influence the overall impact on the environment were outlined: the mass fraction in waste, the recycling rate, the conversion efficiency, the waste-to-energy conversion rate, and the type of energy which can be utilized from incineration generated energy.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Quest for the key to malic acid production by Aspergillus oryzae Monique Geyer, Willie Nicol, Hendrik Brink University of Pretoria, Pretoria, South Africa

Abstract The petrochemical industry has been the focus of research and development for many years and is the norm for many chemical processes. The potential to produce bulk valuable chemical precursors, like malic acid, from microbial bioconversion has been proposed for many years but is still being researched to a lesser extent. Malic acid is a specialty chemical that is mainly used in the food and beverage industry. Aspergillus oryzae is a natural producer of malic acid using various renewable sugar substrates and nitrogen sources. Before venturing into this avenue for biomass-based production of malic acid, the influence of process parameters on scalability needs to be investigated.

This project aimed to: (i) investigate the trigger for malic acid production by A. Oryzae; and (ii) classify the driving force for this. This was tested in both a novel bio-reactor that used immobilised A. Oryzae NRRL 3488 and shake flasks experiments. The fermentation strategies tested various morphologies (fungal and buffer), 1-step vs 2-step acid cultures, and various types of buffers such as potassium phosphate, NaOH, CaCO3 and MgCO3. The influence of different CaCO3 concentrations was also investigated.

A two-phase fermentation strategy in the bio-reactor using NaOH as neutralising agent resulted in some malic acid production. However, after 205 hours only 6 % of the initial glucose was consumed with 3.34 g/L of malic acid produced which was significantly lower than the amounts reported in the literature. Citric acid was the main catabolite produced followed by malic acid and then pyruvic acid.

To investigate the influence of morphology and pH control on malic acid production, shake flasks were employed that used pellet or immobilised morphology with a pH buffer. Fermentations with a phosphate buffer and pellet morphology did not produce any malic acid or by-products and were ineffective at maintaining the pH above 6 (after 48 hours pH was below 5). The addition of 40 g/L NaHCO3 with the phosphate buffer improved pH control for both immobilised and pellet morphology experiments and resulted in the production of organic acids. The 2 different morphologies yielded similar results for organic acid production with malic acid the main product followed by succinic acid, citric acid, and then ethanol which was not previously reported as a by-product.

The one-step fermentation method was validated in shake flasks with dosing of CaCO3 whereby it was seen that the flasks with higher concentrations of CaCO3 measured higher concentrations of malic acid. The influence of CaCO3 concentration on the ability of A. oryzae to produce malic acid was investigated using 3 different concentrations: 20 g/L, 80 g/L, and 120 g/L CaCO3. It was found that 120 g/L CaCO3 performed the best with 89 % of the glucose consumed where 45 % was converted to malic acid. Following was 80 g/L CaCO3 with 78 % glucose consumption (35 % to malic acid) and lastly 20 g/L CaCO3 with 68 % of the glucose consumed (19 % to malic acid). It was also found that up to 4 times more biomass was produced with 80 g/L and 120 g/L CaCO3 when compared to 20 g/L. Of interest, it was decided to add powdered CaCO3 at the start of the fermentation and after 24 h. It was found that this did not significantly improve the amount of malic acid produced but did change the morphology of the biomass (filamentous instead of pellet). These results suggested that CaCO3 played a more significant role than just controlling the pH. 47 | P a g e

Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid Further experiments showed similar results when MgCO3 was used in the same carbonate ratio as CaCO3. MgCO3 had a lower glucose consumption rate (50 % after 300 hours) when compared to CaCO3 where all the glucose was consumed after 200 hours. Samples measured before and after acidification with HCl showed no significant difference in the amount of malic acid measured which suggested the calcium-malate precipitation mechanism was not an influencing factor as previously hypothesised.

The study tested various parameters to find the key to malic acid production with A. Oryzae and found that the role of CaCO3 was an integral part of the quest.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid Loyiso Nqakala University of the Western Cape, Cape Town, South Africa

Abstract The steam cracking of hydrocarbons remains the major method for the production of important olefins such as ethylene and propylene that are vital as feedstocks in the petrochemical industry.

Nevertheless, high reaction temperatures (800-850 ºC) require huge amount of energy intake and high CO2 emissions demands that the development of a more environmentally friendly technology for the production of olefins. The catalytic cracking of the hydrocarbon feedstocks over zeolite catalysts occurs at lower temperatures of 500-650 ºC allows for more favourable propylene to ethylene ratios. However, the ZSM-5 zeolite catalysts suffers from low diffusion restrictions of the bulky reactants and products due to their small micropore sizes which lead to slow transportation of bulky reactants and products to and from the active sites. To overcome this problem, generating mesoand/or macropores inter-connected with microporous network of zeolite while maintaining its catalytic activity has become one of the major solutions to the problem. Therefore, increasing the pore size in the synthesized ZSM-5 will reduce the diffusion limitations and will also reduce the amount of coking which leads to deactivation. This study focuses on the synthesis of hierarchical macro/mesoporous ZSM-5 zeolite crystals with variable Si/Al molar ratios in order to enhance selectivity to propylene in the catalytic cracking of refinery naphtha to produce light olefins. The prepared material was heated in Teflon-lined steel autoclaves at high temperatures, normally above 150 ºC to produce crystalline zeolites. The effect of Si/Al ratio of ZSM-5 on its acidity, porosity, morphology and crystanility will be established. The effect of Si/Al ratio will also be established on the activity, selectivity and stability of the catalyst. Catalytic cracking activity will be evaluated using a quartz-tube reactor setup. From the XRD patterns of the synthesized HZSM-5 with different Si/Al ratios in the range 30-300, the peaks observed at ~ 1.8-2º in the inset represent a certain degree of ordering of the mesoporous structure.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Wastewater remediation using municipal solid waste-derived hydrochar Christine Dewah, Marx Sanette, Roelf Venter North-West University, Potchefstroom, South Africa

Abstract Industrialization and population growth increase the generation of solid waste and the release of toxic pollutants that is of environmental concern. Therefore, novel approaches for both wastewater remediation and solid waste management are a necessity. Current bio-waste adsorbents, such as biobased activated carbon are expensive, because of the elevated temperatures required for adequate preparation and activation. A promising alternative that can be chemically activated without the need for high temperature is hydrochar produced via hydrothermal liquefaction of organic waste. The comparative advantage of hydrochar over other bio-waste adsorbents is the high concentration of surface functional groups that act as adsorption sites for heavy metals and phenolic components This study explored the use of hydrochar as a bio-adsorbent in the removal of alkali and alkaline earth metals (AAEM) and phenolic components from a simulated wastewater stream of the HTL process (HTL-AQ). Furthermore, the possibility of recovering adsorbed components was also investigated. The hydrochar, prepared from HTL of the organic fraction of municipal solid waste, was activated by washing with a KOH solution with a concentration of 1.0 mol/L. The observed maximum adsorption capacities of the hydrochar for metals in wastewater (HTL-AQ) was K+ (121.3 mg/g, Ca2+(156.2 mg/g), Mg2+ (8.7 mg/g), Na+(76.9 mg/g), Fe2+ (0.68 mg/g) and for phenolics vanillyl alcohol (62.8 mg/g), resorcinol (47.5mg/g), phenol (27.6 mg/g) and guaiacol (6.1 mg/g). The removal efficiency was determined precisely in the order phenol (92%) >Fe2+ (77%) >guaiacol (73%) >resorcinol (59%) >Mg2+ (53%) >vanillyl alcohol and Ca2+ (52%) >Na+ (51%)>K+ (47%). Ca2+ and Mg2+ adsorption is best described by henry isotherm, while Freundlich Isotherm best describes Na+ and K+ and phenolics. Ca2+ and Mg2+ adsorption is best described by Henry isotherm, while Freundlich Isotherm best describes Na+ and K+ and phenolics. The adsorption mechanism of both metals and phenols can be described as a physisorption process on heterogeneous surface limited by intraparticle diffusion. Over 75% of metal and 65% phenolics was recovered using 1.0mol/L HCl and 1.0mol/L KOH respectively and the hydrochar can be reused efficiently up to the third cycle. Therefore, this study highlights the ideal opportunity of hydrochar replacing fossil-based or synthetic bio-waste adsorbents in wastewater treatment and contributing positively to the United Nations sustainable goal of “clean water and sanitation.”

Keywords; wastewater remediation, hydrochar, hydrothermal liquefaction, adsorption, metal, phenolics

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

A Simulation Study of the Combined Process of Torrefaction and Gasification of Lignocellulose Biomass (Bagasse) for Syngas and Methanol Production Lanrewaju Ibrahim Fajimi, Bilainu Oboirien, Johnathan Chrisostomou University of Johannesburg, Johannesburg, South Africa

Abstract Biomass is an underutilized energy resource that now supplies around 10% of the world's energy and has the potential to meet more than 25% of the world's energy demand by 2035 [1]. Methanol is one of the most important organic compounds in the chemical industry, as it is used as a raw material to make several industrial chemicals [2]. This study investigates a comprehensive process for the coproduction of syngas and/or methanol from bagasse. The sugarcane bagasse proximate, ultimate analysis, and the heating value employed in this study were obtained in a previous study by Anukam et al. (2018) [3]. Overall, four scenarios were considered in this study, they are bagasse gasification for syngas production with torrefaction (S1), bagasse gasification for co-production of methanol, and syngas with torrefaction (S2) while the other two (S3 & S4) are without torrefaction process. The gasification process was modelled in Aspen Plus using a kinetic-free equilibrium model using steam and pure oxygen as the gasification agent as shown in Fig. 1. For the syngas cleaning, the rectisol process was employed while for the methanol synthesis, hydrogenation reactions of CO2 and CO coupled with the water gas shift reaction were employed. From the result obtained, the process involving torrefaction has more syngas yield hence more methanol was synthesized (0.37kgMeOH/kgBagasse) when compared to the process without torrefaction (0.33kgMeOH/kgBagasse). The syngas from the torrefaction processes also have higher lower heating values (LHV) of 9.24 MJ/kg and 8.76 MJ/kg for S1 and S2, when compared to that without torrefaction (S3 & S4) with LHV of 9.07MJ/kg and 8.58 MJ/kg respectively as shown in Fig 2. In addition, the S1, S2, S3, and S4 have the tendency of generation energy of 17.67 MW, 20.33 MW, 17.46 MW, and 19.30 MW respectively. Hence, the process with torrefaction has proven to be an ideal pretreatment process for the generation of energy for electricity and/or methanol production from bagasse gasification.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Mass spectrometry data processing method for calculation of kinetic coefficients Vladislav Badenko, Ilya Sosnovsky, Alexander Kozlov Melentiev Energy Systems Institute SB RAS, Irkutsk, Russian Federation

Abstract Thermogravimetric analysis with mass-spectrometry is applied to determine propertries of various materials, including biomass. The most interesting kinetic coefficients to study are the activation energy and pre-exponential factor A of Arrhenius equation. For TG or DSC data that parameters are calculated using following methods, such as ASTM E 698-18 and Vyazovkin integral method. But these methods for determining the kinetic coefficients are based on the isoconversion principle, according to which the reaction rate at a constant conversion rate is only a function of temperature and are focused on processing weight loss curves or thermal effects rather than mass spectrometry data.

Obtaining the kinetic coefficients from the mass-spectrum data involves few specific feature, different from TG and DSC analysis.

In this paper, proposed a method for processing the spectrograph signal obtained during the TGA-MS study. As input data the method uses the dependence of ion current on temperature I(T) for the investigated component and carrier gas together with the experiment parameters: temperature T(K), transport gas flow rate Vtr (ml/min), heating rate b (K/min), sample mass m (mg), residual sample mass mres (mg), moisture mass mmoi (mg). The calculations take into account only the effective mass meff , calculated taking into account the unreacted residue. The parameter F, which is used to calculate the activation energy Ea and the pre-exponential factor A, binds the input data by relation (1): On calculating of this parameter, the ion current signal of the investigated component is normalized to the similar signal of the transport gas. The dimensionality of F is -.

This method uses the approximation α→I(T). Based on this, pre-exponential factor is found as the maximum of the function Fs normalized to the abscissa axis and has a similar dimension to F and the tangent angle of the direct linear correlation of Fs on the inverse temperature is numerically equal to the activation energy Ea: In this research activation energy, calculated by method, was used to investigate chemical mechanism of wood pyrolysis.

In general, method allow to evaluate the formation of the components and compare various materials, based on mass-spectrometry data. This allows an improved study of the properties of various materials and the mechanisms of chemical reactions

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Investigation of the effect of supports on sulfided nickel catalysts for propane dehydrogenation Tayyibah Tahier, Ebrahim Mohiuddin, David Key, Masikana Mdleleni UWC, Cape Town, South Africa

Abstract Light olefins are an important raw material for the petrochemical industry. With the rise in oil prices and increasing demand for olefins, there is an increasing interest in finding cheaper alternatives for processes in the petrochemical industry. The dehydrogenation process represents a route to obtain olefins from feedstocks of inexpensive hydrocarbons. Commercial catalysts based on chromium or platinum have major disadvantages, including the harmful effects of chromium and the high cost of platinum, which limit their application. Therefore, developing efficient dehydrogenation systems using environmentally friendly and inexpensive metals have become highly desirable.

Nickel catalysts displayed high catalytic activity but low selectivity toward olefins in isobutane dehydrogenation. Instead, cracking reactions occurred at a rapid rate, with methane and coke being generated in relatively large quantities.1 Sulfided metal catalysts have since gained significant interest for the dehydrogenation process as they display interesting catalytic activity. The promoting effects of sulfur can be explained in terms of two aspects. The first is the geometric effect, diluting aggregated metal species, thereby inhibiting C-C bond rupture. The second aspect is an electronic effect to facilitate alkene desorption, leading to increased selectivity towards the desired products.2 Although sulfided catalysts have been prepared on various supports, not much attention has been paid to the effects of supports on the physicochemical properties of the catalyst such as textural properties, particle size, acidity and metal-support interactions and their relation to activity, selectivity and stability of the catalysts. In this study, sulfur-promoted nickel catalysts supported on MgAl2O4 and SiO2 were investigated for the dehydrogenation of propane.

Materials and Methods The loading of Ni(II) by weight was 13 wt% Ni for all catalysts. Nickel oxide catalysts supported on MgAl2O4 and SiO2 were prepared by incipient wetness impregnation using Ni(NO3)2.6H2O as the metal precursor. The sulfur modified catalysts were prepared with loadings of 20wt% SO42- (Ni:S, 1:1). The sulfur catalysts were obtained by sequential impregnation of the supports with aqueous Ni(NO3)2.6H2O and (NH4)2SO4 solutions. The catalysts were evaluated in both the sulfated form, NiO/MgAl2O4-20wt%SO4 and NiO/SiO2-20wt%SO4, in addition to the reduced form, Ni/MgAl2O420wt%SO4 and Ni/SiO2-20wt%SO4, which contained the sulfided species. Physicochemical properties of the catalysts were determined using XRD, BET, TEM, TGA, NH3-TPD, FTIR, and TPR to investigate the particle size, surface area, morphology, acidic properties and stability of the catalysts on both MgAl2O4 and SiO2 supports.

Structural and textural characterization of the catalysts revealed that NiO/MgAl2O4-20wt%SO4 and Ni/MgAl2O4-20wt%SO4 displayed highly dispersed particles in comparison to the catalysts on the SiO2 support. STEM analysis showed that the NiSO4 and Ni3S2 particles formed localised clusters on the SiO2 support. These clusters were effectively absent on the MgAl2O4 support. The metal-support interaction was stronger on the MgAl2O4 support as indicated by TPR analysis. Peaks occurring at 53 | P a g e

Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid higher temperatures on NiO/MgAl2O4-20wt%SO4 correspond to the decomposition of sulfur, which contributes to the stability of the catalyst, since the loss of sulfur is associated with the deactivation of the catalysts.

References 1

D. E. Resasco, B. K. Marcus, C. S. Huang and V. A. Durante, J. Catal., 1994, 146, 40–55.

2

G. Wang, C. Gao, X. Zhu, Y. Sun, C. Li and H. Shan, ChemCatChem, 2014, 6, 2305–2314.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Creating community microgrids containing biomass gasifiers Nikita Tomin1, Vladislav Shakirov1, Alexander Kozlov1, Denis Sidorov1, Victor Kurbatsky1, Christian Rehatanz2, Electo E. S. Lora3 1

Melentiev Energy Systems Institute of SB RAS, Irkutsk, Russian Federation. 2TU Dortmund, Dortmund, Germany. 3Federal University of Itajuba, Itajuba, Brazil

Abstract The paper aims to present a unified approach to building and optimally managing the community microgrids with an internal market, given the social, environmental, and economic benefits of a particular location of such a community. This approach integrates the stages of community microgrids planning and functioning. We propose a concept of building environmental communities of microgrids, with joint use of biomass gasifiers and other renewable energy sources (the sun, wind).

This study proposes a model of a community microgrid operator (Community EMS), which redistributes revenues and expenses between participants, ensuring Pareto efficiency. Community EMS manages the community to maximize its social welfare by optimizing energy flows and interactions between microgrids and the external grid. Each microgrid has its local management system (Local EMS) to optimize the power flow, with a view to minimizing the total operating costs of an individual microgrid to ensure the internal power balance and determine the required amounts of electricity purchase and sale.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Characterization and Analysis of Keratinous Material for Animal Feed Production Mpho Kekana1,2, Bruce Sithole1,2, Roshini Govinden3 1

University of KwaZulu-Natal, College of Agriculture, Science and Engineering, School of Engineering, Durban, South Africa. 2Biorefinery Industrial Development Facility, Council for Scientific and Industrial Research, Durban, South Africa. 3University of KwaZulu-Natal, College of Agriculture, Science and Engineering, School of Life Sciences, Durban, South Africa

Abstract Keratin is known to be one of the most abundant proteins which can be derived from wool, feathers, nails, hair, and other sources. A large number of keratinous by-products are mostly disposed and others are found in landfills. The disposal methods cause environmental pollution like air, water, and soil pollution. There are different degradation methods of the keratinous by-product to industrial processing for different applications.

Our focus is on the research done for the degradation of the keratinous material into animal feeds using enzymatic hydrolysis, which is known to be of biotechnological interest due to the quality and quantity of the hydrolysate formed. The quality and quantity of the hydrolysate are determined by using a combination of analytical techniques, where the characterization is done via proximate and ultimate analysis. And to focus on the importance of using different characterization techniques and the analysis of the enzymatic hydrolysate from the different microorganisms to determine the quality and the quantity of the animal feed.

The hydrolysate formed from the enzymatic hydrolysis is known to contain a mixture of amino acids and peptides. These peptides and essential amino acids formed are known to play a special role in some of the biological activities.

Different fungal and bacterial strains were tested for the degradation of chicken feathers for the beneficiation of animal feed.

We used Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), CHNS Analysis, and Bradford assay for the characterization of the enzymatic hydrolysate formed.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Assessment and feasibility of converting municipal organic waste into biogas using Anaerobic Digestion: A South African case-study Gaogane Jephtah Gaogane University of KwaZulu-Natal, Durban, South Africa

Abstract

The present energy crisis in South Africa warrants the need for alternative and sustainable energy supply. As a sustainable clean energy carrier, biogas has been demonstrated to be a promising renewable energy source for the generation of heat and electricity (1). The organic fraction of Municipal Solid Waste (MSW) has been reported as a promising feedstock for biogas production (2,3) and characterisation of MSW is the basis towards successful waste to energy programs (3,4). The use of inappropriate equipment and technology choices based on insufficient data on waste volumes and composition, has resulted in the failure of many interventions previously introduced in South African municipalities (4).

Assessing the composition and quantity of available biomass for anaerobic digestion (AD), suitable pre-treatment technologies to enhance biogas production as well as optimization of AD parameters such as pH, temperature and substrate ratio were the core components of this research project. The digestate was evaluated and potential use as fertilizer assessed. A mesophilic bench-scale AD of Cow Dung (CD) and Fruit and Vegetable waste (F&V) obtained from a F&V market was conducted. F&V forms the greatest waste in the country (5), and this facility generates on average 2560 tonnes of waste per annum. This study concludes that utilisation of MSW for AD relies heavily on characterisation data, which is only possible through separation at source. The study recommends the development of a municipal organic waste facility and equally important, prohibition of landfilling from high-end food chains. Other technologies such as Mechanical Biological Treatment (MBT) can be revisited for possible waste to energy programs at landfill leading to landfill space savings and reduced pollution. Waste pickers at landfills can be employed for this purpose as separation specialists.

Bench-scale AD revealed that the benefits of substrate pre-treatment outweighed the effects of codigestion ratio and pH. Reducing particle size from 1-2mm to <1mm, doubled the methane gas generation in a much shorter time and removed pH induced microbial inhibition in unbuffered reactors. Optimal pH was observed at 7.5-8.5. A co-digestion ratio of 80:20 (CD:F&V) produced higher methane yield for all pH variations in comparison to 60:20. The Digestate measured an average volatile solids loss of 46.4% with a C:N ratio of 12 and a heating value (HV) of 4.30 MJ/kg. Metal analysis of digestate showed presence of Nb, Sr, Si, N, P and K as constituents returned to the soil.

1.

Demirbas A, Taylan O, Kaya D. Biogas production from municipal sewage sludge (MSS). Energy Sources, Part A Recover Util Environ Eff [Internet]. 2016;38(20):3027–33. Available from: http://dx.doi.org/10.1080/15567036.2015.1124944

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid 2.

Hilkiah Igoni A, Ayotamuno MJ, Eze CL, Ogaji SOT, Probert SD. Designs of anaerobic digesters for producing biogas from municipal solid-waste. Appl Energy. 2008;85(6):430–8.

3.

Ayeleru OO, Ntuli F, Mbohwa C. Municipal solid waste composition determination in the City of Johannesburg. Lect Notes Eng Comput Sci. 2016;2226:625–9.

4.

Oelofse SH, Muswema AP, Koen R. The changing face of waste management – considerations when conducting a waste characterisation study. Proc 23rd WasteCon Conf 17-21 Oct 2016, Emperors Palace, Johannesburg, South Africa [Internet]. 2016;(October):345–9. Available from: https://researchspace.csir.co.za/dspace/handle/10204/8948 5.

Oelofse S. Food waste research for South Africa. CSIR [Internet]. 2019;1:2–4. Available from: www.csir.co.za

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Production of dissolving wood from sawdust waste material Simiksha Balkissoon1,2, Jerome Andrew1, Bruce Sithole1,2 1

CSIR BIDF, Durban, South Africa. 2University of kwazulu-natal, Durban, South Africa

Abstract The shift towards a more sustainable bio-based economy is focussed largely on repurposing waste products to more valuable chains. The concept of a biorefinery is acquiring much interest across industries globally. Circular economies and waste beneficiation are becoming the epitome and future of industrial processes.

Waste generation and accumulation remains a universal challenge across all industries. However, for the Forestry, Timber, Pulp and Paper (FTPP) sector, the stakes are much higher with considerable losses making the industry financially vulnerable. According to Sithole (1), the low timber utilization rate is a broad challenge faced by the FTPP sector since more than half of the wood biomass in the form of bark, chips and sawdust goes to waste. Sawdust waste is generated primarily from timber processing at saw mills and from the wood chipping and screening processes at the pulp and paper mills. Although there are no recent figures available, in 2010 it was estimated that forestry and wood processing in South Africa generated about 4-6 million tons of wood waste per annum, mainly as residues in the plantations and as sawdust and offcuts at the saw mills and pulp mills (2). From all the sawmills in SA, close to 440 000 tonnes per annum of sawdust waste are generated from 218 saw mills (3). Waste management practices include incineration, stockpiling or landfilling, which are not sustainable options going into the future.

Dissolving wood pulp (DWP) is a high purity cellulose product increasing demand for the last several years (4). DWP is mainly produced from wood chips or cotton. The former being a limited resource whilst the latter is rather costly. For this reason, other raw material sources are constantly being evaluated as potential candidates for feedstocks for DWP production. DWP itself has shown a remarkable end-user product versatility. Different grades of DWP are used in several end-user products manufactured in the pharmaceutical, food and paint and coatings industry.

Two established methods of producing DWP are the prehydrolysis kraft process (PHK) and the acid sulphite (AS) process (5-7). These traditional methods are complex, involving several stages that are energy, water and chemically intensive. The proposed study aims to address some of the aforementioned challenges faced by the FTTP sector by producing a grade of DWP from sawdust waste using a propriety technology being developed. The proposed study foresees many benefits: by using sawdust waste as a raw material and minimising the associated challenges related to waste generation and accumulation and wood losses, reducing the pressure of our already exploited wood resources, and generating revenue for the industry by reducing processing costs and redirecting waste to more profitable margins.

The study focussed on optimisation of a benchtop scale process followed by an upscaled pilot plant process. The pulps obtained were then chemically characterised and compared against commercially available grades of DWP. Traditionally hardwood species are used for the production of DWP. 59 | P a g e

Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid However, the proposed study has evaluated both hardwood and softwood species and preliminary results show that a grade of DWP may be produced from both wood species thereby expanding the resource chain. Results to date show that the grade of DWP obtained using the proposed process may be suitable for the production of microcrystalline cellulose (MCC). Further modifications to render it suitable for other products such as viscose is currently in progress.

References 1. Sithole B. Opportunities and challenges for the forest sector in contributing to the South African Bioeconomy. Durban: University of Kwa-Zulu Natal and CSIR; 2017.

2. Timberwatch. 4. Appendix - the State of Forestry in South Africa Today 2010 [Available from: http://www.timberwatch.org.za/old_site/archives/2000807stateofforrestry.htm.

3. Stafford WHL, Lange WJD. Wood-based Bio-refineries: Value adding to sawmill waste from the Forestry industry. CSIR; 2018. Contract No.: CSIR/NRE/GES/IR/2018/0044/A. 4. Potgieter MS. Improving dwp quality using brown stock fractionation. Durban: Durban University of Technology; 2018.

5. Astuy TL. Developments in a sulphite pulping process for the valorisation of its carbohydrate resources within the biorefinery concept. Spain: University of Cantabria; 2016.

6. Strunk P. Characterisation of cellulose pulps and the influence of their properties on the process and production of viscose and cellulose ethers. Sweden: Umea university; 2012.

7. Yang B, Wang B, Wang G, He Z, Ni Y. Integrated Forest Biorefinery:Value-added Utilization of Dissolved Organics in the Prehydrolysis Liquor of Prehydrolysis Kraft (PHK) Dissolving Pulp Production Process. Integrated Forest Biorefinery. 2018;3(3):47-58

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Valorization of waste chicken feathers: Electrospun nanoparticles-embedded keratin composite nanofibers

antibacterial

Lebogang Mphahlele1, Bruce Sithole1,2 1

University of Kwazulu Natal, Durban, South Africa. 2Biorefinery Industry Development Facility, Council for Scientific and Industrial Research, Durban, South Africa

Abstract Chicken meat is the highest consumed meat in South Africa with a per capita consumption of >33 kg yearly. Hence, South Africa produces over 250 million kg of waste chicken feathers each year, the majority of which is landfilled or incinerated (1). The discarded feathers have caused environmental pollution and natural protein resource waste. Therefore, valorization of waste chicken feathers is measured as a more environmentally friendly and cost-effective treatment (2). Feather contains 91% protein, the main component being beta-keratin, a fibrous and insoluble structural protein extensively cross-linked by disulfide bonds. Keratin is usually converted into nanofibers via electrospinning for a variety of applications. keratin nanofiber composites have many potential biomedical applications for their attractive features such as high surface-to-volume ratio and very high porosity. The application of nanofibers in the biomedical wound dressing requires antimicrobial properties for materials. One approach is incorporating inorganic nanoparticles, among which silver nanoparticles played an important alternative antibacterial agent and have been studied against many types of microbes (3).

The objective of this study is to combine synthetic polymer, chicken feather keratin, and antibacterial nanoparticles to develop novel electrospun antibacterial nanofibrous composites for possible wound dressing application. Furthermore, this study will be converting a two-dimensional electrospun nanofiber membrane to three-dimensional fiber networks that resemble the structure of the extracellular matrix (ECM)

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid

Production of bio-coal from wastewater sludge-biomass feedstock Zinhle Mkhwanazi Durban University of Technology, Durban, South Africa

Abstract The increasing volume of wastewater sludge, sugarcane bagasse from wastewater treatment, and sugarcane facilities is becoming a prominent concern globally. The disposal of sludge is particularly challenging and poses severe environmental hazards due to the high content of organic, toxic, and heavy metal pollutants among its constituents. The emissions from burning sugarcane bagasse are known to have an impact on respiratory health. At the same time, the availability of energy supply is in demand. The reliance on fossil fuels in the 21st century is unsustainable as the world's reserves are limited and are continually depleting. This depletion of reserves demonstrates the need for alternative energy sources. In order to minimize the reliability of fossil-based energy sources, a renewable resource such as biomass can be optimized as an energy source. Wastewater sludge and bagasse have the energy potential to produce a high calorific value bio-coal, this will contribute to the supply of energy in South Africa. South Africa is a major consumer of coal, mainly to produce electricity therefore the development of renewable energy is essential to reduce fuel shortage as concerns for clean and sustainable energy grows. The synthesis of bio-coal from wastewater sludge and bagasse through an artificial synthetic coal production process, i.e. hydrothermal carbonization (HTC) is preferred over other thermal conversion techniques as HTC is capable of handling feed having a high (75-90%) moisture content. This study focuses on the production of bio-coal from wastewater sludge and sugarcane bagasse as an alternative to sustainable bioenergy supply and is one of the potential solutions for reducing net CO2 greenhouse gas (GHG) emissions from fossil-fuel power plants.

This study followed the application of the HTC process, with the purpose to convert wastewater sludge and sugarcane bagasse to valuable bio-coal. The wastewater sludge and sugarcane bagasse were subjected to hydrothermal carbonization in stainless steel batch reactors, where the effect of temperature, solid loading (solid-liquid wt. %), and biomass type were investigated, and the other process parameters were maintained at a constant. The effect of the following temperatures were explored 180 and 260 A ratio variation of 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100 dry sludge and bagasse(SB), and the composition of solid to liquid (solid loading wt. %) of 1:10, 2:10, 3:10, and 4:10 (SB:H2O) to achieve 9.09%, 16.67%, 23.08% and 28.57% were investigated. The process yielded gaseous products, a solid phase, and an aqueous phase. Calcium hydroxide was used as a binding medium for the produced bio-coal.

The results obtained in this study revealed that solid loading, temperature, time, biomass type, and its ratio variation had a substantial impact on the yield and calorific value of bio-coal produced. The highest bio-coal yield of 23.36 wt. % was achieved at 210°C derived from sludge/bagasse (S/B) with sludge content of 20% and 23.07 wt. % from pure sludge at 180°C. Across all runs, the highest calorific value of 20.21MJ/kg was achieved at 260ºC when pure bagasse was employed (0% sludge content).

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Comparison of Biodiesel production routes parameters using castor bean and jatropha oils Gabriel Baioni e Silva1, Tainá Manicardi1, Andreza A. Longati2, Cintia R. Sargo3, Electo E. S. Lora1, Thais S. Milessi1

1

Federal University of Itajubá (UNIFEI)

2State University of Campinas (UNICAMP) 3

Brazilian Biorenewables National Laboratory (LNBR)

Abstract The concern about environmental problems and climate changes has led to many efforts in the transition of global energy matrix toward renewable sources [1]. In this sense, biodiesel is a renewable and alternative fuel proposal and castor bean and jatropha are interesting non-edible raw materials for its production due to their high fatty acid content [2]. The transesterification is the most common process applied on industrial scale biodiesel production due to its attractive economic characteristics.

This process can be catalyzed by chemical (homogeneous or heterogeneous) or biochemical (enzymatic) catalysts [1]. The choice of raw material, as well as the route of production of biodiesel will significantly influence process parameters.

Considering the importance of biodiesel production in Brazil, especially with the increase of its mandatory blend within commercialized diesel, the present work aimed to compare biodiesel production from these two raw materials through the three production routes. For this, an extensive literature review was performed to select works producing biodiesel from castor bean and jatropha though chemical homogeneous, heterogeneous and enzymatic routes. The software PowerBI was then used to group the selected works according to the pattern of each route influence on process parameters.

In general, the process parameters presented a similar profile in each production route for both raw materials . The enzymatic route stands out with milder reaction temperatures and lower amounts of alcohol, both being an important environmental factor due to the higher energy demand for higher temperatures and considering the use of methanol in the process, which is from fossil sources [3].

However, the significant longer reaction time makes process unfeasible industrially once the use of higher enzyme loads in the reactor is limited by enzyme’s high cost.

It is clear that the homogeneous chemical route presented the most economically interesting parameters when compared to the heterogeneous ones (smaller amounts of catalysts and alcohol as well as the use of milder temperatures and shorter reaction times), however, taking into account the advantages related to biochemical and heterogeneous chemical routes, once solid catalysts are high reactive, led to easy purification and especially easy recovery and reuse, comparative studies of technical-economic analysis between the different routes, as well as environmental impact studies such as life cycle analysis, can help decision making in the search for the most appropriate production route.

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Figure 1 – Influence of biodiesel production route using castor bean and jatropha on process parameters. Where: CAT is the catalyst amount % (w/w) and Molar ratio is the ratio between mols of alcohol and mols of oil

References [1] Milessi TS, Tabuchi SCT, Esteves TD, Hirata DB, Capaz RS, Mendes AA. Biodiesel production in oil biorefinery and by-products utilization. Production of Top 12 Biochemicals Selected by USDOE from Renewable Resources. 2022. DOI: https://doi.org/10.1016/B978-0-12-823531-7.00010-X [2] Osorio-González CS, Gómez-Falcon N, al-Salas FS, Saini R, Brar SK, Ramirez AA. Production of Biodiesel from Castor Oil: A Review. Energies. 2020; 13:2467.

[3] Ramos LP, Kothe V, César-Oliveira MAF, Muniz-Wypych AS, Nakagaki S, Krieger N, Wypych F, Cordeiro CS. Biodiesel: Matérias-Primas, Tecnologias de Produção e Propriedades Combustíveis.

Revista Virtual de Química. 2018;9:317-369.

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Renewable diesel sustainability potential as a complementation for diesel and biodiesel mixtures in Brazil Alisson A. V. Julio, Thais S. Milessi, Eric A. Ocampo Batlle, Diego M.Yepes Maya, Electo E. S. Lora*, José Carlos Escobar Palacio Federal University of Itajubá (UNIFEI)

Abstract The effects of fossil resource use on climate change along with the growing demand for global energy are a model of unsustainability. The use of fossil fuels represent more than 75% of the total consumption [1] and the transport sector is highly responsible for it, especially in Brazil, where transportation is highly dependent on oil, even with policies that demand biodiesel blends in allthe commercialized diesel-like fuels [2] . In this sense, Drop-in biofuels, suchas Renewable Diesel, emerges as a sustainable alternative to replace petrochemical fuels.

Considering Renewable Diesel environmental potential and its capability to overcome limitations of diesel and biodiesel, the present work compared renewable diesel, with diesel and biodiesel, in order to make a case for this new fuel be inserted in the transportation sector in Brazil. For this, a comprehensive literature review was performed to select works onthermochemical production of Renewable Diesel, considering the main routes: Hydrothermal Liquefaction (HTL), Fast Pyrolysis (FP), Fischer- Tropsch Synthesis (FTS), and Hydrotreatment of Vegetable and Waste Oils (HVO).

Therefore, for decision-making to understand the importance of Renewable Diesel in the energy transition of the Brazilian transportation sector, Technical-economic and environmental performance indicators were summarized and put into comparison by means of a radar chart, Figure 1-A. The outcome of such graphic is that the thermochemical process which are still under development phase have higher costs, such as HTL, FP, and FTS.

Figure 1 – A. Techno-economic and environmental performance of fuels and biofuels. B. Composite Sustainability Score of fuels obtained through different thermochemical routes

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid Moreover, to better compare and access the best fuel option on environmental matters, a Composite Sustainability Score for each option was calculated, basedon the values presented on Figure 1-A. The final score is obtained by the sum ofeach value on the prism, multiplied by weighting factors, in which environmentalindicators such as emissions and Global Warming Potential had higher weights (75% total, 50% emissions, 25% GWP). The resulting value of the Composite Sustainability Score is then plotted in Figure 1-B, being the presented in green the best option for this decision scenario, and the red is the worst. Therefore, regardless the production route Renewable Diesel has better environmental performance than biodiesel and diesel, and the HVO route is the most promisingin the near future, indicating that diesel and biodiesel would become less appealing options over time.

References: Long F, Liu W, Jiang X, Zhai Q, Cao X, Jiang J, et al. State-of-the-art technologies for biofuel production from triglycerides: A review.

Renew Sustain Energy Rev 2021;148:111269. https://doi.org/10.1016/J.RSER.2021.111269.

ANP. Biodiesel. 2014.

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Removing impurities from biomass gasification: A BTL review Diego C. de Oliveira1, Electo E. S. Lora1, Osvaldo J. Venturini1, Diego Y. Maya1 1

Federal University of Itajubá - Excellence group in thermal power and distributedgeneration - Av. BPS, 1303, Bloco L7, CEP. 37500-903 Itajubá – MG

Abstract An alternative to mitigate environmental issues related to fossil fuels utilization is the production of liquid hydrocarbons from biomass. They are potential energy carriers, able to be used in internal combustion engines through products like jet fuel, diesel, gasoline, ethanol, biodiesel [1]. Biomass-toliquid route (BtL), in particular gasification integrated to the Fischer-Tropsch (FT) process, is a pathway to achieve this. However, the commercial application of the route still prohibitive due its overall costs and uncertainty, related to many technical challenges, such as gas cleaning and conditioning in order to meet FT requirements [2]. Gas quality is affected by different parameters as feedstock selection and treatment, gasifier and gasification conditions, and finally, cleaning system design and operation.

This work aims to synthesize relevant information on impurities generation and removal techniques, considering the different steps of the process. Feedstock selection is the first step in avoiding impurities in raw gases from biomass. Knowing biomass properties can help in viability evaluation of a given feedstock, prediction and mitigation of potential impurities, and finally design of cleaning systems. The main elements in biomass composition are C, H, N, S and O, and many other trace compounds as Cl, K, Na, heavy metals, etc. coexist with them. During gasification, these elements and gasifying agents (air, steam, O2 CO2) react, resulting in solid, liquid and gaseous products (permanent gases). The goal of a G-FT plant is to obtain a syngas composed mainly of H2 and CO, in a molar ratio of 2, due the requirements of FT synthesis (FTS) catalysts [3], [4]. They are easily deactivated or poisoned by different compounds, considered here as main impurities (particles, tars, NH3 H2S, HCl, alkalis). They can create deposits in catalysts surface (tars, particles) or even cause poisoning (Scompounds and N-compounds). Primary and secondary measures are the so-called mitigation or removal techniques applied inside gasifiers and outside them, respectively. Catalyst beds, catalytic filtration and similar

techniques are primary measures that can increase carbon conversion, tar cracking and ammonia decomposition. These same processes can be performed outside the gasifiers, followed by further unit operations. The main challenge in arranging these techniques is to obtain the strict impurities levels imposed by FTS [3]. Particles must be essentially removed (below to 0.1ppm). It can be achieved only by a combination of techniques for greatest and finest particles removal. Tar concentration must be reduced through conversion (cracking, partial oxidation) or even physical removal (scrubbing, condensation), often required to reduce its concentration and dewpoint, avoiding condensation downstream. S-compounds are considered the most poisonous and must be reduced to concentrations from 60-100ppb to 1ppm [3], [4]. H2S is the most expressive and is soluble in water as NH3, the most expressive N-compound that often requires a dedicated cleaning section to reach levels in the range of 10ppb to 1ppm [3], [4]. Absorption, adsorption and sorption processes occurring at 67 | P a g e

Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid different temperatures and environments are used to remove these and other impurities like H2S and alkali metals, this last ones to ppb concentrations. Arranging the sequence considering the order of hot, warm and cold processes and also impurity removal overlapping is a way to achieve a better overall efficiency. Therefore, as suggestion, a cleaning sequence would be composed of removal techniques as cyclone, sorption bed and oil scrubbing as hot and warm processes, followed by cold processes as water scrubbing and filtration processes with activated carbon and a ZnO (guard bed filter).

References [1] E. Environ, J. C. Serrano-ruiz, and J. A. Dumesic, “Energy & Environmental Science Catalytic routes for the conversion of biomass into liquid hydrocarbon transportation fuels,” pp. 83–99, 2011, doi: 10.1039/c0ee00436g.

[2] I. Dimitriou, H. Goldingay, and A. V Bridgwater, “Techno-economic and uncertainty analysis of Biomass to Liquid ( BTL ) systems for transport fuel production,” Renew. Sustain. Energy Rev., vol. 88, no. February, pp. 160–175, 2018, doi: 10.1016/j.rser.2018.02.023.

[3] H. Boerrigter, H. P. Calis, D. J. Slor, and H. Bodenstaff, “Gas Cleaning for Integrated Biomass Gasification ( Bg ) and Fischer-Tropsch ( Ft ) Systems ; Experimental Demonstration of Two Bg-Ft Systems,” 2nd World Conf. Technol. Exhib. Biomass Energy, Ind. Clim. Prot., no. May, pp. 10–14, 2004, doi: ECN-RX--04-041.

[4] E4Tech, “Review of Technologies for Gasification of Biomass and Wastes - Final report,” 2009.

[Online].Avail.:https://www.e4tech.com/uploads/files/NNFCC_final_report_E4tech_090609.pdf.

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Evaluation of residual biomass for bioenergy production using GIS- MCDM methodology in the state of Minas Gerais Fernando Bruno Dovichi Filho 1, Laura Vieira Maia de Souza1, Electo EduardoSilva Lora1, José Carlos Escobar Palacio1,Quelbis Román Quintero Bertel2 .

1

Grupo de Excelência em Energia Térmica e Geração Distribuída (NEST), Instituto de Engenharia Mecânica, Universidade Federal de Itajubá (UNIFEI), Brasil ( 2

Universidad de Sucre, Colômbia

Abstract Faced with the immediate need for greenhouse gas emission reduction, clean energysources such as bioenergy are being considered [1]. Multi-criteria decision-making methods (MCDM) are becoming popular in solving energy system optimization problems [2]. This research aims to define the most viable types of waste biomass forelectricity generation using a multi-criteria decision making (MCDM) approach. A framework of criteria to be considered during the evaluation was developed. The method employed for the decision analysis was the Analytic Hierarchy Process (AHP),which is a method for assisting people in making complex decisions. It is emphasized, more than determining the right decision, the AHP helps in the process of choosing and justifying those choices. One of the reasons for using AHP as a methodology is that this method includes both quantitative and qualitative criteria [3].

Economic, technical, Social and environmental criteria identified in this research were evaluated by experts with a high level of experience, such as more than 10 years in the area of bioenergy [4].

Evaluating the level of importance of each criterion requires a great understanding of what should really be prioritized for the generation of renewable energy from biomass. Of the 66 micro-regions investigated in the State of Minas Gerais, the culture of Eucalyptus was the one that presented the highest priority, followed by the culture of sugarcane and by the culture of corn. The map of the microregions of Minas Gerais, was generated in the QGIS software, allowing a visualizationof the culture selected in each micro-region, resulting in the Figure 1.

Figure1: Crop selected for each micro-region 69 | P a g e

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Figure: Crop selected for each micro-region

The objective of applying the AHP methodology was to select the most viable residuefor bioenergy generation. To this end, 13 effective criteria were initially identified through literature review for biomass selection. This research presents an AHP methodology applied in GIS to evaluate the availability and feasibility of bioenergy generation based on harvested biomass residues in Minas Gerais, Brazil. Among the technical criteria, the technical potential was considered the primary desirable option for bioenergy generation. The methodology imposed in this research is accessible to any investor or entity focused on the expansion, diversification and selection of the bioenergy matrix and can be replicated for other study analyses with different criteria and subcriteria or be adapted for other available bioenergy residues.

References OLIVIER, J.G.J; PETERS, J.A.H.W. Trends In Global CO2 And Total Greenhouse Gas Emissions.

PBL. Netherlands Environmental Assessment Agency. 2019 SAATY, T.L. The Analytic Hierarchy Process. New York: McGraw – Hill, 1980 KHEYBARI, Siamak et al. Evaluation of energy production technologies from biomass using analytical hierarchy process: The case of Iran. Journal of Cleaner Production, v. 232, p. 257-265, 2019.

KUMAR A, SAH B, SINGH AR, DENG Y, HE X, KUMAR P, et al. A review of multi criteria decision making (MCDM) towards sustainable renewable energy development. Renew Sustain Energy Rev 2017;69:596–609. https://doi.org/10.1016/j.rser.2016.11.191.

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Transformation of biofuels into syngas and hydrogen in reactors with structured catalysts and hydrogen permselective membranes.

V.A. Sadykov1,2, N.F. Eremeev1, L.N. Bobrova1

1

Boreskov Institute of catalysis SB RAS, Novosibirsk, Russia

2

Novosibirsk State University, Novosibirsk, Russia

Abstract Efficient, inexpensive and stable to coking nanocomposite catalysts for transformation of natural gas/biogas/biofuels into syngas and hydrogen were developed comprising of nanoparticles of metals/alloys (Ni, Co, Pt, Ni+Pt, Ni+Ru) supported on perovskites (La1-xPrxMn1-yCryO3-, CaTiO3), fluorite Ln-Ce-Zr-O (Ln = La, Pr, Sm), rutile (Ln)TiO2 and spinel MnxCr3-xO4 oxides with a high oxygen mobility and reactivity, either bulk or supported on Mg-doped alumina or MgAl2O4 with ordered mesoporous structure. Pulse microcalorimetry and transient kinetic studies (including SSITKA and FTIRS in situ for estimation of rate constants of reaction steps) revealed that mechanism of biofuels transformation on these catalysts can be described by a bifunctional red-ox scheme with activation of fuel molecules on Me/oxide sites and oxidants (H2O, CO2, O2)- on reduced sites of the oxide support.

Fast diffusion of surface oxygen (bridging M2O) species to the Me/support interface provides the efficient transformation of activated fuel species into syngas by incorporation into C-C bond, thus preventing coking. Effect of the active component composition, specificity of the surface sites and nature of oxidant on mechanism of biofuels transformation into syngas was elucidated.

Structured catalysts comprised of optimized active components loaded on Ni-Al foams, Fechraloy foils/honeycombs, gauzes and microchannel platelets protected by corundum layers were tested in pilot reactors in steam, dry, partial oxidation and autothermal reforming of biofuels at short contact times using concentrated feeds. A high yield of syngas approaching equilibrium and stable performance without coking were demonstrated even for such fuels as glycerol, sunflower and turpentine oils. Mathematical modeling demonstrated absence of any heat transfer limitations due to a high thermal conductivity of substrates. No spallation or cracking of the active component layers supported on substrates was revealed. Reactors equipped with the internal heat exchanger were designed allowing stable and efficient operation in the autothermal mode of the mixture of natural gas and liquid biofuels at feeds inlet temperatures <50oC. For the renewable/hydrogen energy field, producing syngas and hydrogen from biogas/biofuels using catalytic processes conjugated with reagent (oxygen) and/or products (hydrogen) separation in membrane reactors is a promising approach as well. Unique Ni-Al foam substrates with graded porosity were used for design of such membranes, which allowed to minimize gas diffusion resistance.

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Sustainable Bioenergy and Processes 2021 13-15th December 2021 Cape Town International Convention Centre Hybrid Nanocomposites with mixed ionic-electronic conductivity were applied as permselective layers for oxygen separation (perovskite+fluorite, spinel+fluorite combinations) or hydrogen separation (Ni-Cu nanoalloys + Ln tungstates, niobates etc. protonic conductors). Nanocomposite active components for biofels transformation were supported on membrane surface as well as on the honeycomb substrates placed into membrane reactors. For catalytic oxygen-permeable membrane reactors a high oxygen flux (up to 15 cm3 O2/cm2min) was achieved under air/CH4 (+CO2 + biofuel) feeds gradients at ~ 900 oC, providing a high yield of syngas. For reactors with hydrogen-permeable membranes a better performance was achieved with honeycomb catalyst put upstream, so at ~ 800 oC complete EtOH conversion in steam reforming and a high hydrogen permeation (up to 3 cm3 H2 /cm2 min) were demonstrated. Membranes remained stable without any deterioration of performance or coke deposition. Mathematic modeling using modern software (COMSOL Multiphysics, CFD), step-wise reaction scheme of fuels reforming and mass transport equations provided reliable description of catalytic membrane performance required for up-scaling.

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Transformation of lignocellulosic biomass into energy products Bruce Sithole Biorefinery Industry Development Facility, Council for Scientific & Industrial Research, South Africa

Abstract

2021 marked a pivotal moment in the fight against climate change. For nearly three decades the UN has been bringing together almost every country on earth for global climate summits – called COPs – which stands for ‘Conference of the Parties’. In that time climate change has gone from being a fringe issue to a global priority. For some time, the Earth's natural resources have been depleted faster than they can be replaced. The Intergovernmental Panel on Climate Change has set a 2030 deadline to reduce heat-trapping emissions by half to avoid climate change that is both irreversible and destructive. At the COP26 held in Glasgow, an agreement was reached on curtailing the effects of climate energy. However, countries of the global South who are already facing the worst impacts of the climate emergency have expressed their deep disappointment over how the talks have unfolded.

Guinea, who represented the developing-nation group has expressed "extreme disappointment" at the decision to initiate only an annual "dialogue" to talk about "arrangements for the funding of activities to avert, minimise and address loss and damage". This after the United States, the European Union and some other rich nations, were opposed to the establishment of a dedicated new damages fund for vulnerable nations. Processing of lignocellulosic biomass into energy products is perceived as a viable way in the fight against global warming. This can be achieved by application of biorefinery technologies. Unfortunately, the recalcitrant nature of lignocellulosic biomass hinders the commercialisation of the technologies at large scale. Biorefinery technologies can be implemented via three general biomass fractionation modes: thermal, chemical and biological. This presentation discusses transformation of lignocellulosic biomass into energy products with an emphasis on availability of biomass, impediments to implementation of biorefinery technologies, commercial readiness of technologies, pros and cons of the different technologies, and potential for job creation opportunities. The discussion will also include an assessment of where South Africa is on the technologies.

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The role of biofuels in a sustainable circular bioeconomy Daniela Thrän Bioenergy Systems" departments at the Deutsches Biomasseforschungszentrum gemeinnützige GmbH (DBFZ) and the Helmholtz Centre for Environmental Research (UFZ)

Abstract Bioenergy is the oldest and most important renewable energy. However its provision and use is still under development. Biomass is a renewable resource with a huge potential to serve climate gas mitigation in the field of material, chemicals and energy, but the biomass potential is limited.

Bioeconomy is defined as the production and utilization of biological resources (including knowledge) to provide products, processes and services in all sectors of trade and industry within the framework of a sustainable economy. A sustainable circular bioeconomy needs improving efficiencies, cascading and recycling, synergies with other renewables and valorisation of the renewable carbon. Under this consideration, advanced biofuels, which are well integrated into bioecomony production networks play a major role. This includes better use of residues and waste, high efficiencies and also the coproduction of different fuels and chemicals. First examples of those production networks are already available. Long term strategies for advanced biofuels provision have to be embedded into the whole energy system transformation, land use policies as well as different assessment dimensions. Their straight forward development should always consider the current production and use of biofuels (and bioenergy) as a starting point and put effort on sustainable value chain development.

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Biomass for energy potentials and technology Electo Eduardo Silva Lora Federal University of Itajubá

Abstract Data are presented on the availability of different biomass and residues in Brazil, the selection of biomass with the greatest potential for bioenergy, as well as data in relation to the current generation of electricity from this fuel. The results of the evaluation of the theoretical and technical potentials of biomass electricity generation are also presented, as well as an analysis of the future generation matrix in the country for 2050, maximizing the use of biomass. All this considering factors such as the maturity of biomass generation technologies and the permissible penetration of intermittent renewable energies (wind and solar). The ongoing projects in the Thermoelectric and Distributed Generation Nucleus of the Federal University of Itajubá in Brazil related to the management of the use of biomass and thermochemical conversion processes are described.

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Gasification of biomass; a key technology in energy transition: Challenges and successes Bilainu Oboirien University of Johannesburg

Abstract Biomass gasification has a high potential in energy transition to low carbon or net zero emission. The reason is that biomass gasification can be used in heat and power generation, transport fuel and chemical production and these are key energy utilisation sectors. In this keynote address different biomass gasification technologies that integrate carbon capture and renewable energy storage for combined heat and power, liquid fuels and chemical production will be discussed. The challenges and the successes will be identified, and future areas of research will be presented.

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Assessment of fast pyrolysis for extended-value-chain valorization of residual biomass and organic wastes.

Piero Salatino Università degli Studi di Napoli Federico II, Italy

Abstract Effective conversion of non-food/low ILUC biomass and organic wastes into advanced biofuels discloses an avenue toward increasing exploitation of renewable energy sources, entailing reduction of the dependency from fossil fuels while contributing to the development of modern biorefinery. A promising perspective is represented by the development of an extended-value-chain exploitation scheme based on two-stages: decentralized conversion of raw biomass and organic wastes into biogenic intermediates (“biofeedstocks”) in the proximity of the harvesting/collection sites, followed by their ultimate upgrade/valorisation via centralized biorefinery processes. The medium-term vision is the development of a market of biofeedstocks that can be offered and traded as true “biocommodities” to replace fossil resources as the source of fuels and chemicals, supporting the shift from traditional to bio-refining.

Fast Pyrolysis (FP) fits well into this general framework due to its ability to accomplish high-yield thermochemical conversion of a wide spectrum of residual biomass to high-energy-density and chemically diversified bio-oils. Despite decades of extensive research on biomass pyrolysis, there are still broad unresolved areas that regard the very chemical pathway of biomass depolymerization/secondary reactions and the associated chemical and process engineering criteria aimed at optimizing yield and quality of the generated bio-oil. This lecture aims at contributing to the evaluation of the potential of FP for the distributed generation of tradable biofeedstocks with a focus on the assessment of the reaction pathways and on the development of chemical reaction engineering design and operational guidelines, with a focus on distributed biomass pyrolytic fluidized bed conversion.

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Application of Biofuels in Automotive Engines K A Subramanian Centre for Energy Studies and full professor, Indian Institute of Technology Delhi, India Abstract The utilization of Biofuels in automotive engines/vehicles is imperative to achieve a part of the sustainable goal of net zero-emission by the year 2050. Biofuel is carbon-neutral fuel as well as a carbon sink. The road transport sector accounts for 17% of global greenhouse gas emissions (UNFCCC).

The potential biomass feedstock includes agricultural residue, forest wastes, energy crop products, industrial waste, municipal solid waste, etc., producing biofuels. In addition, Biofuels provides to increase energy security, fuel quality, reduce regulated and GHGs emissions, increase fuel economy with tangible benefits, including expansion of habitat and food web, improving soil quality, preventing soil erosion, and oxygen generation.

Biofuels such as methanol (CH3OH), ethanol (C2H5OH), biomethane (CH4), biodiesel, dimethyl ether (CH3-O-CH3), Fisher-Tropsch Diesel (CxHy), and Bio-hydrogen (H2) are derived from the biomass through biological/thermochemical conversion processes. Biofuel is generally having lower sulfur content resulting in negligible SOx emission from combustion engines. Biofuels have higher octane numbers (100 (Methanol), 100 (ethanol), 110 (biomethane), 120 and above (biohydrogen)) and higher cetane numbers (58 (Biodiesel), 58 (Dimethyl ether), 75 (Fisher-Tropsch Diesel)) compared to gasoline (95 Octane Number) and diesel (51 Cetane Number).

High octane number biofuels (methanol, ethanol, biomethane, biohydrogen) are used in sparkignition automotive vehicles for applications of two and three-wheelers and passenger cars. High cetane number biofuels (Biodiesel, DME, F-T Diesel) are used in compression ignition vehicles for mainly buses and trucks. Biohydrogen could also be used in proton exchange membrane (PEM) fuel cells.

The thermal efficiency of automotive engines fuelled with biofuels is higher due to an increase in combustion efficiency. The octane number, which is higher with biofuels than that of base gasoline, would be helpful to increase the compression ratio of the engines and hence, higher thermal efficiency. The oxygen embedded in hydrocarbon (CxHyOz) is mainly responsible for lower smoke/soot / PM as well as CO and HC emissions.

The biofuel blends (ethanol-blended gasoline (E5, E10, E15, E85), methanol blended gasoline (M5, M10, M20, M85), biodiesel blended diesel (B5, B20), hydrogen blended methane (18%HCNG)) is being implemented worldwide in automotive engines until the complete infrastructure will be developed for the biofuels. Flexible vehicles with multi-fuels compatibility (gasoline and ethanol, methanol and gasoline, CNG and Hydrogen, etc.) for spark-ignition vehicles and dual fuels (ethanol-diesel, methanoldiesel, biomethane-Diesel, Hydrogen-Diesel, etc.) for compression ignition vehicles working under Reactivity Controlled Compression Ignition (RCCI) mode play a pivotal role for the transition from conventional fuels to green fuels (biofuels). Later, 100% biofuels (M100, E100, B100, and H2) could be implemented in automotive vehicles for attaining transport sectors a net zero-emission.

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Recent advances on sustainability and production of bioenergy through integrating hydrodynamics and process culturing using advanced measurement, experimentation and computing techniques Muthanna H. Al-Dahhan Missouri Univ. of Science and Technology (Missouri S&T), USA

Abstract Sustainability and production of bioenergy are achieved through emerging multidisciplinary technologies that have been growing fast in recent decades. Despite the large number of studies and effort made to advance these technologies, their understanding and efficient industrial implementations are still lacking due to the difficulties of performing integrated studies that need advanced measurement, experimentation and computing techniques. We have been able to overcome some of these difficulties in our research laboratory of Multiphase Flow and Reactors Engineering, and Education Laboratory (mFReel). As a result, we have made significant contributions in advancing the understanding of key parameters and phenomena of selected bioenergy processes by implementing novel approach of integrating advanced multi-scale experimentation and engineering modelling using advanced measurement techniques that we have developed over the years. To demonstrate such novel integrated approach that we have taken in addressing some of the shortcomings facing in general the bioenergy processes, and in particular the following bioprocesses that we have advanced and studied which will be overviewed in this lecture: Microalgae culturing in ponds and photobioreactors for bioenergy production, flue gas treatment, wastewater treatment, feed, single cell protein, pigments and pharmaceutical high value products production.

Anaerobic digestion of animal waste to treat the animal waste and to generate biogas as bioenergy.

A new integrated process for bioethanol production from the lab to industrial implementation.

Biomass gasification for bioenergy and for solid biomass waste treatment.

Conversion of Byproduct of biodiesel production to useful chemicals Concept of Integrated biorefinery.

Extending research facilities and findings into multi-disciplinary educational undergraduate and graduate experiments

These advancements have been augmented with advanced measurement, experimentation and computing techniques that will be as well overviewed and the findings and the results of such advancement will be discussed.

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info@sbpconf.com Cape Town 13 - 15 December 2021