Sorption-enhanced steam gasification of fine coal waste for fuel producing

Abstract

Improving the quality of syngas from fine coal waste using the sorption-enhanced gasification process is a novel technology in the production of H₂. The effect of CaO on CO₂ absorption and H₂ increase in the steam fine coal gasification process was determined in a fixed bed gasifier. The steam gasification process took place at 650 °C using bentonite and CaO as catalysts and absorbents. Steam increased the H₂ concentration in the syngas to 58 vol%. In-situ CO₂ absorption is more effective with the addition of CaO. The maximum percentage of CO₂ was absorbed when the Ca/C ratio 2 was 78.33 %. The H₂ content in the syngas after the CO₂ was absorbed increased rapidly to 75.80 vol% at a Ca-to-carbon-mole ratio (Ca/C) of 1.5 and a steam-to-feedstock ratio (S/F) of 1.5. CaO did not produce significant results for low heating value (LHV) or cold gas efficiency (CGE), with results of 12 MJ/Nm³ and 44.53 %. The dominant water gas shift reaction due to the influence of steam and CaO increased H₂/CO up to 9.11, which made the syngas from this work suitable for Fischer–Tropsch synthesis.