Zinc Chloride Catalysis in Coal and Biomass Liquefaction at Prepyrolysis Temperatures

摘要

Coal liquefaction processes currently under development operate with thermal decomposition of coal. This step is nonselective, and wastefully forms light hydrocarbon gases and refractory char as byproducts. It requires severe operating conditions (over 400 exp 0 C and 100 atm.), giving rise to high capital costs, and relatively low thermal efficiencies. In the present study, coal liquefaction has been investigated under milder, more selective conditions, utilizing a zinc chloride-methanol melt as a liquid-phase catalyst. Operating at 275 exp 0 C with 35 to 55 atm. of H sub 2 , this catalytic medium has been found to give over 95% conversion of Wyodak subbituminous coal to solvent-extractible, but not yet truly liquid, products. The products are identified in a standard manner as oils, asphaltenes, and preasphaltenes, with hydrogen-to-carbon atomic ratios in the ranges of 1.2 to 1.4, 1.0 to 1.1, and 0.8 to 0.9, respectively. (ERA citation 07:013635)