Modeling and Analysis of Post-combustion and Pre-combustion CO2 Capture Processes

Abstract

Climate change and its consequences have raised global awareness to reduce the anthropogenic emission of greenhouse gases, especially Carbon Dioxide (CO2). Among the various sources of the CO2 emission, power plants combusting fossil fuel such as coal, oil and gas occupy the most amount of CO2 emission. Several methods of removing CO2 from power plant flue gas have been proposed, and post-combustion and pre-combustion capture processes are most widely used candidates. Although post-combustion capture process is known as the most mature and economically feasible technology, its high energy consumption and efficiency penalty associated with process retrofit still remain as an obstacle towards commercialization. Pre-combustion capture process, on the other hand, has higher efficiency than the conventional coal power plant and has no penalty associated with capturing CO2. Although pre-combustion capture is more energy efficient and environmental-friendly, its high economic barrier still makes it difficult to be widely implemented. In this study, both options of CO2 capture process are modeled with reliable data source and analyzed technically and economically. For the post-combustion capture process, mechanical vapor recompression process is suggested as a solution to reduce the energy consumption to regenerate the absorbent. For the pre-combustion capture process, lean vapor compression, which is a widely used configuration for post-combustion capture, is also applied to reduce the steam consumption in the acid gas removal unit. As another application derived from the IGCC plant, substitute natural gas production process is also proposed which can produce a methane-rich product from coal.