Pseudo counter-current turbulent fluidized bed process with sensible heat recovery for energy-efficient CO2 capture using an amine-functionalized solid sorbent

Abstract

A fluidized bed adsorption (FLBA) process with internal heat integration is considered an energy-efficient method for large-scale CO2 capture. Herein, we propose a pseudo counter-current FLBA process for post-combustion CO2 capture as a proof-of-concept based on a rationally designed moving bed heat exchanger by incorporating the internal heat integration concept of the conventional amine scrubbing CO2 capture process. The proposed FLBA process consists of an adsorption bed, desorption bed, and moving bed heat exchangers for cooling and heating the solid sorbent. The design of the proposed FLBA process enables internal heat integration by recovering sensible heat from the cooling process. Furthermore, by installing multiple adsorption processes, the pseudo counter-current operation in the adsorption bed enhances the CO2 cyclic capacity of the amine-functionalized solid sorbent with high CO2 recovery. The proposed process complements the two weaknesses of FLBA, namely, large sensible heat and low cyclic capacity of the sorbent. The energy analysis, based on rigorous mathematical modeling, estimates that the energy demand of the optimized FLBA using SiO2/0.37 EB-PEI is approximately 258.6 kWh/t-CO2 with 45% sensible heat recovery. This low energy demand is comparable to that of the most mature amine-based absorption process (271 kWh/t-CO2) owing to the effect of internal heat integration, supporting the feasibility of the FLBA process for post-combustion CO2 capture.