Simulation Optimization of a New Ammonia-Based Carbon Capture Process Coupled with Low-Temperature Waste Heat Utilization

Although ammonia-based CO2 capture has attracted global research attention, several inherent issues with this technology remain to-be resolved. To address these problems, a new design for carbon capture using ammonia is proposed on the basis of anti-solvent crystallization, also known as precipitation crystallization. The crystallization of a low carbonized absorbent was found to-be, enhanced in the crystallizer using an-anti-solvent process, which can maintain a high absorption rate and simultaneously prevent crystallization from occurring in the absorption tower. Energy consumption for sorbent regeneration is, reduced by regenerating the crystal product rather than the rich-solution. Energy-cascade utilization-is an effective way to improve the use of energy. In this work, steam was used to drive a heat pump that extracts energy from discharged flue gas from a wet flue gas desulfurization system in. a power plant to enablethe recovery of low-temperature residual energy; this energy can be used in the crystal regeneration process, thereby further reducing the energy required for regeneration. Aspen Plus (version 8.4) software was adopted:to simulate the flue gas condensation, heat-pump circulation, and steam drive'-subsystems. The simulation results showed that 10 heat pumps (6.04 MW) can meet the regeneration energy requirement of the CO, capture process in a 300 MW coal-fired unit and recycle 40.6 MW of low-temperature heat. The extraction steam requirement is low, which reduces the impact on power-generation.