Process analysis of improved process modifications for ammonia-based post-combustion CO2 capture

Abstract

Carbon-based fuels contribute majorly towards global energy demand; however, it results in global warming. The increasing energy demand and climate change highlights the need to develop cost-effective carbon sequestration schemes. Amine-based CO2 scrubbing have been widely used for their high selectivity and production of pure CO2. However, a challenge in implementing amine-based technology is high energy consumption with a low capture ratio. The energy penalty can be reduced either by introducing new solvents, optimizing parameters, or through process modifications. Recently, ammonia has tempted attraction in place of amines. In this present work, a Radfrac model in Aspen Plus is developed involving heat integration and absorption enhancement to overcome the barriers. The heat integration is performed with a rich solvent split and absorption enhancement is done with split flow arrangement. Further, the model is evaluated at different split ratios by performing heat integration between different streams of the flowsheet. Moreover, the process configurations used in this system is compared with MEA based process modifications concerning energy reduction. A competitive reduction in regeneration duty was observed which was 36% less than the reference NH3 and 47% less than the MEA process. This evaluated modification will result in maximum efficiency, a maximum level of CO2 capture, and a reduction in the reboiler duty. The rich solvent split and split flow process reduced the reboiler duty by 15.8% and 32.8%, respectively. The split flow process also indicated an increase of 17.2% in rich loading to recover 90% CO2.