Thermodynamic analysis of sorption-enhanced water-gas shift reaction using syngases

Abstract

Sorption-enhanced water–gas shift (SEWGS) reaction performance using syngas as the feedstock is investigated in this study based on thermodynamic equilibrium analysis. It was found that the capability of CO2 sorbent in CO2 removal was independent of the dry syngas composition. Regardless of the dry gas composition, CO2 sorbent loses its adsorption capability as the reaction temperature increases higher than a temperature limit. This CO2 adsorption temperature limit was found to depend on the steam to carbon (SC) ratio and reaction pressure. With the decrease in SC and increase in pressure the CO2 adsorption temperature limit can be raised to a higher value. However, the initial CO2 content in the syngas composition affects the carbon and CH4 formations in SEWGS. For syngas with low CO2 concentration, carbon formation can be completely eliminated and CH4 formation can be reduced by CO2 removal. For syngas with high CO2 concentration, no carbon and CH4 suppression can be found. It was also found that the temperature at which no carbon and CH4 formations was increased to a higher value as the initial CO2 concentration was increased. Copyright © 2016 John Wiley & Sons, Ltd.