Fuel, Vol.178, 272-282, 2016
High-purity hydrogen production from ash-free coal by catalytic steam gasification integrated with dry-sorption CO2 capture
This study is aimed at the improvement of process conditions for catalytic steam gasification of ash-free coal (AFC) integrated with CO2 capture. A novel modified catalytic hydrogen production reaction integrated gasification (M-HyPr-RING) process was proposed for high-purity H-2 production from steam gasification of AFC. AFC was prepared from lignite coal by solvent extraction with maximum yields of 67% on a dry ash free basis at 400 degrees C using hydrotreated heavy aromatic hydrocarbons with a coal-to-solvent ratio of approximately 1: 10. The gasification temperature and sorbent-to-carbon (CaO/C) ratio were maintained constant for all experiments at 675 degrees C and 2, respectively, as determined by our previous findings. The steam gasification experiments were conducted on AFC in a fixed-bed reactor in the presence of different catalyst loadings (5, 10 and 20 wt% of potassium carbonate) with and without sorbent. A maximum hydrogen molar fraction of 85% (dry basis with nitrogen) was observed with catalyst loading of 20% and CaO/C of 2 after 5 min of steam gasification under mild process conditions. (C) 2016 Elsevier Ltd. All rights reserved.