Decarbonisation Technology - November 2021

Capturing green opportunities Well-designed post-combustion carbon capture technologies can benefit businesses in the energy sector

Marcel Suhner Sulzer Chemtech

T he capture, sequestration and utilisation of carbon dioxide (CO 2 ) is a key strategy that businesses can adopt to reduce their emissions. By implementing the right technologies, they can meet ambitious climate change mitigation strategies while benefitting from new revenue streams. Sulzer Chemtech offers a cost-effective solution for efficient systems that can maximise the amount of CO 2 captured with minimal energy consumption. Being mostly stationary sources, oil and gas facilities can potentially cut their environmental impact and global warming potential (GWP) by leveraging post-combustion, or post-conversion, carbon capture and storage (CCS) as well as carbon capture, utilisation and storage (CCUS) strategies. CCS and CCUS solutions remove CO 2 from flue gases and store the compound underground or use it in extractive and industrial processes. In CCUS applications, there are multiple opportunities to use the captured CO 2 , with end uses that vary greatly. 1 For example, the recovered emissions can be used to produce manufactured goods or for enhanced oil recovery (EOR), a method to optimise oil extraction using CO 2 to maximise yields in mature wells and store it underground. By utilising or selling the gas for any of these uses, power plants can therefore reduce their environmental footprint while benefitting from additional revenue streams. How carbon capture works CCS or CCUS solutions can be added to existing infrastructures, e.g. as part of a retrofit project. Therefore, any processing and manufacturing plant can potentially incorporate these technologies. Moreover, almost all of the CO 2 produced on site can be captured using well-designed systems. For instance, Boundary Dam Unit 3 plant in

Saskatchewan, Canada, can sequestrate up to 90% of its CO 2 emissions. 2 As a result, highly effective setups can reduce the GWP of power plants by 63- 82% per unit of electricity generated, as estimated by lifecycle assessments on CCUS technologies. The most common process utilised in existing carbon capture systems relies on an amine-based amine scrubbing treatment, whereby CO 2 is chemically absorbed onto amine-based solvents. The CO 2 rich flue gases enter the bottom of an absorber column, where they make contact with a down-flowing liquid amine-based solvent, such as generic monoethanolamine, methyldiethanolamine or proprietary amine solvents formulation by process licensors. The rich solvent is sent to a stripping column. There, the absorption reaction is reversed (desorption) and the CO 2 can be compressed into a supercritical fluid for storage or utilisation, while the lean solvent is recycled to the top of the absorber for reuse. Maintain peak performance and efficiency While the process described is established and already utilised in commercial settings, businesses are sometimes reluctant to adopt it because of the capital and operational expenses that may be required. In effect, these systems need to handle particularly challenging separations, as they process high volumes of flue gases that have limited CO 2 concentrations. For example, a CCS/ CCUS line for an 800 MW coal-fired power plant may need to be able to handle up to 3 million m 3 of flue gases emitted by the plant every hour to recover the CO 2 from flue gases with CO 2 in the range of 3.5 to 14 vol%. 4 Nonetheless, the right equipment can minimise the costs, material use and energy required for the intensive capture and compression phases. To select effective solutions, businesses should work together with an experienced specialist. More