Continuous Operation Experiences of SEWGS for Hydrogen Generation with CO_2 Capture from Coal Gasifier Syngas

摘要

SEWGS (Sorption Enhanced Water Gas Shift) process is one of options for pre-combustion CO_2 capture using dry absorbent and water gas shift catalyst. In this process, the thermodynamic equilibrium in the shift reaction can be enhanced to give more hydrogen yield by adding a CO_2 absorbent into the shift reactor. Total integrated system consists of coal gasifier, warm gas cleanup process (two interconnected fluidized bed desulfurizer), and one loop SEWGS process. In this paper, continuous operation results of the warm gas cleanup process and one loop SEWGS process using dry absorbents at high temperature and pressure conditions were discussed. Dry absorbents were produced by KEPCO RI (Korea Electric Power Corporation Research Institute) by means of spray-drying method. Continuous operation was performed at high pressure (21 bar for gasifier, 20 bar for warm gas cleanup process, and 18 bar for SEWGS process) and reaction temperature was 550 °C for desulfurizer and 227 °C for SEWGS reactor. Totally integrated operation was maintained up to 32 hours. We could get high sulfur capture efficiency more than 99 % in the desulfurizer, high CO conversion more than 97 % and CO_2 capture efficiency more than 90 % in the SEWGS reactor.