Sorbent enhanced hydrogen production from steam gasification of coal integrated with CO_2 capture

摘要

In this work, CO_2 capture and H_2 production during the steam gasification of coal integrated with CO_2 capture sorbent were investigated using a horizontal fixed bed reactor at atmospheric pressure. Four different temperatures (650, 675, 700, and 750 ℃) and three sorbent-to-carbon ratios ([Ca]/[C] = 0, 1, 2) were studied. In the absence of sorbent, the maximum molar fraction of H_2 (64.6%) and conversion of coal (71.3%) were exhibited at the highest temperature (750 ℃). The experimental results verified that the presence of sorbent in the steam gasification of coal enhanced the molar fraction of H_2 to more than 80%, with almost all CO_2 was fixed into the sorbent structure, and carbon monoxide (CO) was converted to H_2 and CO_2 through the water gas shift reaction. The steam gasification of coal integrated with CO_2 capture largely depended on the reaction temperature and exhibited optimal conditions at 675 ℃. The maximum molar fraction of H_2 (81.7%) and minimum CO_2 concentration (almost 0%) were obtained at 675 ℃ and a sorbent-to-carbon ratio of 2.