7 minute read
TECHNOLOGY
Reliable Measurements Mean New Opportunities for Carbon Capture
By Justin Walsh
According to the National Climate Assessment (NCA), human activities release over 30 billion tons of carbon dioxide into the atmosphere
annually. These emissions contribute to the greenhouse effect that is causing temperatures and sea levels to rise as well as a surge in increasingly severe weather events across the globe.
The reality of the climate crisis is forcing many global leaders to commit to significant reductions in carbon emissions. For policymakers to meet these important targets, they will need to leverage new technologies to capture, use and store carbon dioxide (CO2) before it is released into the atmosphere. This is supported by recent US federal government investments in R&D and Carbon Capture facilities in both the CHIPS and Inflation Reduction Acts of 2022.
Carbon capture utilization and storage methods present a path forward in ways that can be scaled to make a significant impact. However, as these operations grow, measurement and control challenges arise. The continuous monitoring of CO2 is difficult, as exhaust gases from incinerators can be corrosive and potentially explosive. Until recently, the only solution was to extract samples for analysis outside of the process. However, this method has several inherent flaws, such as the need to remove humidity from the sample line and requirements for frequent recalibration. Additionally, the manual extraction and analysis process means there is also no way to retrieve near real-time data, creating the potential for decreased efficiency.
In a pilot project using Vaisala technology, researchers from the Technical University of Denmark (DTU) demonstrated that it is possible to remove most of the CO2 from the emissions of a waste incinerator. To simplify the process of capturing CO2 before it enters the atmosphere, Vaisala CO2 sensors are being used to measure reliably in the most demanding environments. By showing the viability of the CCUS process, the researchers believe they have developed a new fundamental technology in the fight against climate change.
The Decarbonization Technology Pilot Project
The Amager Bakke waste-to-energy plant is one of northern Europe’s largest combined heat and power (CHP) plants, treating 560,000 tons of waste annually. Developed by the Copenhagen-based waste management company ARC (Amager Resource center), the CHP plant plays a significant role in the Danish capital’s ambitions of meeting zero carbon requirements by 2025.
The incineration of 1 ton of municipal waste releases between 0.7 and 1.7 tons of CO2, depending on the content of the waste. Consequently, energy generation from waste incineration is more carbon-intensive than burning fossil fuels, so carbon capture and utilization offer a particularly enticing opportunity for this application.
Initially developed to capture CO2 from the emissions of wastewater treatment, biogas production, anaerobic digestion and waste incineration processes, the pilot project saw DTU researchers investigate the optimized processes by which CO2 can be captured and then utilized to determine economic feasibility.
Exhaust gas from the Amager Bakke incinerator is passed through an electrostatic precipitator to remove particulates, NOx compounds are removed by selective catalytic reduction and a scrubber removes oxides of sulfur. The gas then passes upwards through a column packed with beads and a monoethanolamine (MEA) solvent which separates the CO2 from the gas. The solvent is then passed to a desorber which removes the CO2, which is now almost pure, and regenerates the MEA for re-use.With its primary purpose being the investigation of the
Justin Walsh
feasibility of its capture, the pilot carbon capture plant employs three Vaisala probes to measure CO2 levels. The MGP261 monitors incoming incinerator exhaust gas, the MGP262 measures the purity of the extracted CO2, and the GMP251, a Vaisala CARBOCAP® CO2 probe, checks the levels of CO2 (after carbon capture) in the pilot plant’s exhaust gas.
Measuring CO2 levels at every stage is crucial to verify the validity of this process. Demonstrating that carbon can be removed from emissions before they go into the atmosphere, and that the CO2 captured during this process is nearly pure and able to be stored for later use, highlights the possibility of employing a solution like this to
PHOTO: INSTALLATION OF THE VAISALA MGP261 reduce emissions. As this process is more widely recognized, it can be utilized more cost-effectively in waste treatment facilities across the globe.
“The recent COP26 climate change conference in Glasgow highlighted the urgent need for technologies that can help reduce global emissions of greenhouse gases such as CO2,” said Jens Jørsboe, a DTU researcher. “Many countries have committed to net-zero targets, so our work at the Amager Bakke waste-to-energy plant provides an opportunity for them to invest in one of the ways in which that objective can be achieved.”
While the technology is not new, researchers from DTU are now focused on lowering the cost of carbon capture, making it more feasible for other plants to implement similar solutions.
There are many different industrial applications in which CO2 can be utilized. For example, CO2 can be combined with hydrogen to produce methane (renewable natural gas, RNG). This can be a green method for manufacturing fuel, depending on how the hydrogen is generated. Since CO2 is also used in various other industries, including food and beverage, refrigeration, medical, horticulture, firefighting, and welding, a variety of potential markets are available if the heat-trapping gas can be easily produced on a commercial quality and scale. The Result: Hope for a Carbon-Neutral Future
By validating the carbon capture process with Vaisala’s measurement solutions, DTU researchers have shown that this process is a viable solution to the waste emissions problem. With continuous inline monitoring, the researchers have optimized carbon capture performance in 12 different pilot plant configurations.
Having proven the viability of the carbon capture process at Amager Bakke, the next step is to evaluate the advantages of carbon storage and utilization. CO2 utilization, however, is more costly as it requires further refinement of the CO2. Nevertheless, researchers hope this technology will be leveraged in waste treatment facilities worldwide. With the proper regulatory framework and subsidization, the tons of carbon dioxide that would usually be released into the air could now be used across myriad industries to improve our world.
The impact of climate change is becoming increasingly apparent in our everyday lives. We must utilize technology as we push toward a future where the coming generations can enjoy environmental safety and prosperity by leveraging sustainable practices. Carbon capture, utilization and storage technologies, such as the gas probes and sensors used in this case, will play a progressively more significant role in the fight against climate change by providing accurate, real-time data in even the most extreme environments to validate and optimize processes.
Author: Justin Walsh Business Development Engineer Vaisala justin.walsh@vaisala.com
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