Gasification of low-rank coals in supercritical water was carried out in an autoclave by heating temperature to 690 °C and elevating autogenous pressure to 30 MPa. An attempt was made to investigate the catalytic effect of calcium hydroxide on the gasification. It was found that the presence of Ca(OH) 2 facilitates the extraction of volatile matter from coal and the decomposition of the volatile matter to small molecule gases, with a decrease in the amount of residual char. The production of H 2 is enhanced by the catalytic effect of Ca(OH) 2 both on the water-added degradation of the volatile matter and on the gasification of the coal char, despite a slow procession of the char gasification. Moreover, Ca(OH) 2 serves to capture CO 2 as CaCO 3 . After the slurry of Ca(OH) 2 and a Yallourn coal with the Ca/C molar ratio of 0.6 had been heated at 690 °C and 30 MPa, the yields of H 2 and CH 4 were, respectively, 0.35 and 0.18 NL/g of coal (daf), with little gaseous CO 2 and liquid products.
No takes yet. Share an insight, caveat, or question.
Wang et al. (2001) studied this question.