Exergy Recuperative CO2 Separation Process
Carbon dioxide capture and storage (CCS) technology is a promising technology for CO2 emission reduction and climate change mitigation. CCS is not commercialized due to its intensive energy cost, especially for the CO2 capture processes. Basically, there are three kinds of technologies for CO2 capture: post-combustion, pre-combustion, and oxy-combustion [3]. Among them, the post-combustion capture method plays an important role, as it eliminates the need for substantial modifications to existing stationary fossil fuel fired power plants. The most commonly used CO2 separation for post-combustion is chemical absorption process using monoethanolamine (MEA), which consists of an absorber and a stripper (regenerator). In this process, CO2 gas is absorbed by the amine solution with lean CO2 concentration in the absorber, and stripped out from the rich amine solution in the stripper when heated up with the stream from a reboiler. However, the intensive energy consumption of the regeneratin part prevents its application in industry. In addition, the sizes of the absorber and stripper equipment are huge due to the relatively slow heat and mass transfer rate, further limiting its application in industry. Therefore, it is desirable to reduce the energy consumption of CO2 separation process and reduce the size of the equipment. Recently, an exergy recuperatin technology has been developed for post-combustion CO2 separation process, significantly reducing the energy consumption of CO2 separation process.
In this study, we applied the exergy recuperation technology on the CO2 separation process, which not only reduce the energy consumption but also reduce the size of equipments. The simulation showed that the energy consumption of the proposed process was reduced by more than 30% comparing to the conventional process. Experimental work was also conducted to compare with the simulation work.