Biomass cofiring potential and experiences in the Netherlands - ECN

Biomass Cofiring Potential and Experiences in The Netherlands

RenĂŠ van Ree, Rob Korbee, Theo de Lange, Simon Eenkhoorn, Bas Groenendaal Netherlands Energy Research Foundation ECN Biomass Systems

International AFB-net Cofiring Workshop Grenoble, France, 14-15 September 2000

CONTENTS • • • • • • • •

Dutch renewable energy policy -> contribution of biomass Available coal and natural gas fired power plants Status current cofiring projects “Advanced” co-firing concepts Technical, environmental, and economic constraints Discussion/conclusions ECN’s co-firing activities Acknowledgement

Dutch Renewable Energy Policy Contribution of Biomass Summer 2000 policy agreement government and •Biomass contribution: 26% power production companies: Biomass policy goal [PJth, a.f.f.u.]

6 Mt CO2Technology 2000 2007 2020 Domestic wood comb.

8 8 8 reduction in 2010 Industrial wood comb.

5 5 5 -> Co-firing in fossil fuel fired 3 18 20 3 Mt by cofiring power plants biomass in coal Decentral CHP production 2 6 30 fired power plants Biogas (waste disposal sites, -> 20% cofiring digestion) 6 8 8 Others 4 Total 24 45 75

•10% renewable energy in 2020 (288 PJth,a.f.f.u.)

ECN’s Cofiring Activities (1) • System Assessments - steady-state integral thermodynamic system analysis -> overall mass and energy balances -> net electrical system efficiencies [%LHV] - technical system assessments -> system bottle-necks -> “de-bottle-necking” - environmental system assessments (incl. LCAs) -> gaseous, liquid, solid system emissions - applicable air/water emission constraints - commercial applicability of solid waste streams (ashes, gypsum) - financial-economic system assessments -> specific investment costs [Euro/kW e] -> investment decision criteria (POT, NPV, ROI) -> costs of avoided CO2-emissions -> biomass fuel costs versus power production costs

ECN’s Cofiring Activities (2) • Experimental work -

-

-

Thermal conversion (gasification, pyrolysis, combustion) of biomass/waste streams fuel gas/syngas/flue gas compositions/contaminants slagging/fouling behaviour Fuel gas/syngas clean-up/conditioning technologies for application of biomass-derived gas in downstream equipment particles, tars, HCl, H2S, NH3, alkali-metals, H2/CO-ratio, ...

Bottom-ash and fly-ash characterisation the influence of biomass-derived contaminants on the quality of these ash fractions and on their commercial applicability For the experimental work ECN owns a large variety of lab-scale and bench-scale facilities (see conference proceedings)

Acknowledgement

The work presented has been performed in the framework of the in-house RD&D-programme “ENergy Generation In the Natural Environment (ENGINE) of ECN and was co-funded by the Dutch Agency for Energy and the Environment (NOVEM)

Coal Fired Power Plants in The Netherlands Power plant

Owner

Net capacity Lifetime [MWe] Gelderland-13 EPON 602 1983-2011 Amer-8 EPZ 645 1981-2010 Amer-9 EPZ 600 1994-2023 Borssele-12 EPZ 403 1988-2012 Maasvlakte-1 EZH 518 1989-2013 Maasvlakte-2 EZH 518 1988-2012 Buggenum-7 for sale 253 1994-2023 Hemweg-8 UNA 630 1995-2024 Total coal fired power production capacity: 4170 MWe EPON = Electra-Bel (Belgium) EPZ = ESSENT (Netherlands) EZH = Preuβen-Elekra (Germany) UNA = Reliant Energy (U.S.A.)

Natural Gas Fired Installations in The Netherlands • Natural gas fired boilers: mainly for industrial heat production more than 900 installations, overall capacity > 4600 MWth • Natural gas fired gas turbine installations for CHP production more than xxxx installations, overall capacity > 4325 MWe -

power production: gas turbines integrated with a condensing steam turbine (low heat/power-ratio) -> overall capacity > 6000 MWe

-

> 60% built after 1990 -> dry low-NOx combustion chamber

-

< 40% built before 1990 -> water/steam injection facilities

Current Cofiring Activities in The Netherlands Power plant Gelderland-13 Amer-8 Amer-9 Borssele-12 Maasvlakte 1/2 Buggenum-7 Hemweg-8 1

Type of Type of fuel cofiring indirect demolition wood direct paper sludge gasification demolition wood direct phosphor furnace gas direct Biomass pellets1 direct poultry litter direct variety direct sewage sludge

[kt/yr] 60 75 150 23 150 40 ?

75

% cofiring (energy) 3 0.3 5 3 5 4 ?

3

CO2-em.red. [kt/yr] 110 11 170 ?

78 60 ?

92

Status operational operational test phase operational operational tested study tested

Demolition wood / sewage sludge: negative view from the public (heavy metal emissions) 2 Biomass pellets: 60 w% paper/cardboard, 24 w% waste wood, 16 w% compost

Short-term Additional Cofiring Activities in The Netherlands (1) • •

•

• • •

EPON Cofiring percentage of the Gelderland-13 power plant 3 -> 10% (relatively clean fuels), by: 1) expanding the current indirect cofiring capacity, 2) direct cofiring, 3) upstream gasification (without add. gas clean-up).

Cofiring of sewage sludge/high calorific waste streams in the gas-fired Eems power plant (1675 MWe). Technology: upstream gasification with a very extensive fuel gas clean-up system. Maximum cofiring capacity: 100 MWth (3% total energetic natural gas input).

EPZ Direct cofiring of 6-12 kt/yr sewage sludge in Borssele-12 power plant.

Co-firing capacity expansion in all their coal fired power plants.

Technologies: direct cofiring and upstream gasification (and pyrolysis?)

Short-term Additional Cofiring Activities in The Netherlands (2) • •

• • • • • •

EZH Increasing the quality of the Biomass pellets that are currently being cofired (5%) in the Maasvlakte power plant by potentially integrating an additional fuel drying process.

Direct cofiring of 40 kt/yr poultry litter (4%) planned.

UNA Direct cofiring of 75 kt/yr sewage sludge (3%) in the Hemweg power plant planned.

Potentially two vacuum pyrolysis units (Pyrovac) for cofiring purposes planned. Capacity: 120 kt/yr biomass.

Demkolec Direct and indirect cofiring of biomass and waste streams in the Buggenum coal fired IGCC plant (253 MWe). Plant for sale.

Future activities depending on new plant owner.

“Advanced” Future Cofiring Concepts ECN study co-funded by NOVEM •

To meet Policy Agreement: current 0 - 5% -> 20% cofiring in coal fired power plants (CO2-emissions ~ gas fired plants). Longer-term > 20%

•

Which cofiring concepts are available (coal fired power plants and natural gas fired CCs)?

What is their potential?

- net electrical biomass conversion efficiency [%LHV]?

- necessary additional specific investment costs [Euro/kW e]?

•

• •

What are the technical and environmental cofiring constraints?

What is the financial potential of the cofiring concepts?

-> preferable biomass cofiring concept combinations

“Advanced” Future Cofiring Concepts Technical and Environmental constraints • • • •

Technical constraints (coal fired power plants) Pretreatment section: size reduction, quality control, dust explosion danger Boiler: large gas volume, fuel burn-out, slagging/fouling behaviour, (HT) corrosion/deposition/erosion danger Flue gas clean-up: capacity ESP, deactivation SCR-catalyst, DeSO x-capacity, emission constraints concerning heavy metals

-> Most of the technical problems have already been solved.

-> Further (experimental) attention need: - the slagging and fouling behaviour - the (HT) corrosion problems

â&#x20AC;&#x153;Advancedâ&#x20AC;? Future Cofiring Concepts Economic Constraints Net electrical efficiency biomass [%LHV], specific costs additional investment [Euro/kWe], operation time [hrs/year], specific financial criteria for Dutch situation -> price of fuel that can be converted economically as function of the profit of Main financial criteria: the produced electricity subsidy (EIA+Vamil): 25% on add. inv. depreciation time: 10 year tax: 35% Coal price: 1,63 Euro/GJth ...

“Advanced” Future Cofiring Concepts Technical and Environmental constraints • • •

•

Environmental constraints EU air emission constraints applicable for (large-scale) power plants.

Commercial applicability of produced solid waste streams (fly-ash, gypsum (bottom-ash)).

ECN-study EU emission constraints

Influence cofiring on quality of ashes and gypsum

Maximum allowable component content in biomass fuel Spreadsheet with indicative power plant data

Clean biomass fuels (EU): No problem emissions (particles, NOx, SO2) to the air expected.

Contaminated biomass fuels (EU): a variety of components are critical.

Distribution biomass fuel components to the gas phase, the solid phases (ashes, gypsum), and the liquid phase (waste water)

Contaminated fuel cofiring -> heavy metals to solids -> critical?

Clean fuel cofiring -> no critical influence on quality expected

â&#x20AC;&#x153;Advancedâ&#x20AC;? Future Cofiring Concepts Cofiring concepts and their potential Concept direct cofiring indirect cofiring separate gasification - without fgcu (FW) -with fgcu (Lurgi) separate pyrolysis - slow without pgcu - slow with pgcu - fast (Pyrovac) separate HTU separate combustion with steam-side integration

Biomass input [MWth] 151/622 158/649

Net electrical Necessary additional efficiency specific investment biomass part [%LHV] costs [Euro/kWe] 39,6 35/20 38,0 500/285

157/648 169/695

38,1 35,6

455/300 1120/730

167/688 186/765 166/682 170/697 155/639

35,9 32,3 36,1 35,4 38,6

895 1240 935 620/490 940/575

Cofiring in a CC by separate gasification with fgcu (Lurgi) Cofiring percentage Biomass input Net electrical Necessary additional [% total, energy basis] [MWth] efficiency specific investment biomass part [%LHV] costs [Euro/kWe] 5 (6.1) 38 44.3 1500 10 (12.1) 75 44.3 1340 20 (23.7) 151 44.3 1180

Base-case coal fired combustion plant: - 600 MWe - Net eff.: 40 %LHV - 6000 hrs/yr 10% / 40% cofiring Base-case natural gas fired CC: - 335 MWe - Net eff.: 55%LHV - 6000 hrs/yr 5, 10, 20% cofiring

Discussion/conclusions (1) •

Policy agreement government - power production companies concerning CO2-emission reduction coal fired power plants -> 20% cofiring in 2010

•

Current cofiring activities: mainly direct cofiring in coal fired power plants (< 5% of total energetic plant input).

Six main concepts have been identified to increase the cofiring capacity of coal fired power plants: further direct cofiring, indirect cofiring, separate gasification, separate pyrolysis, separate HTU and separate combustion with steam-side integration.

Preferable concepts for clean biomass fuels (EU): direct cofiring, separate gasification without fgcu.

Preferable concepts for contaminated biomass fuels: separate gasification with fgcu and slow pyrolysis with pgcu. A cheaper alternative could probably be mixing these fuels with clean fuels.

•

• •

Discussion/conclusions (2) •

•

•

• •

For cofiring in natural gas fired CCs, the biomass has to be gasified upstream, after which the fuel gas has to be cleaned extensively, before the gas is mixed with natural gas to be combusted in the CC. The main technical constraints that have to be solved (experimentally) for cofiring of biomass in coal fired power plants are: fouling/slagging and (hot) corrosion.

The main technical constraint that has to be solved for biomass cofiring in natural gas fired CCs is to get a better insight in the maximum amount of LCG that can be burned in relatively new gas turbines with dry low-NO x burners.

For clean biomass cofiring no problems are expected concerning applicable EU air emission constraints and the quality of produced solid waste streams.

For contaminated biomass fuels both aspects need further research.