Sorbent enhanced hydrogen production from steam gasification of coal integrated with CO2 capture

Abstract

In this work, CO2 capture and H2 production during the steam gasification of coal integrated with CO2 capture sorbent were investigated using a horizontal fixed bed reactor at atmospheric pressure. Four different temperatures (650, 675, 700, and 750 °C) and three sorbent-to-carbon ratios ([Ca]/[C] = 0, 1, 2) were studied. In the absence of sorbent, the maximum molar fraction of H2 (64.6%) and conversion of coal (71.3%) were exhibited at the highest temperature (750 °C). The experimental results verified that the presence of sorbent in the steam gasification of coal enhanced the molar fraction of H2 to more than 80%, with almost all CO2 was fixed into the sorbent structure, and carbon monoxide (CO) was converted to H2 and CO2 through the water gas shift reaction. The steam gasification of coal integrated with CO2 capture largely depended on the reaction temperature and exhibited optimal conditions at 675 °C. The maximum molar fraction of H2 (81.7%) and minimum CO2 concentration (almost 0%) were obtained at 675 °C and a sorbent-to-carbon ratio of 2.