Publications Details

Impacts of initial reaction chemistry on direct coal liquefaction processes

Stohl, F.V.

The initial reactions that occur during liquefaction can have significant impacts on process yields and downstream process conditions. Reactions that result in compounds with low molecular weights and decreased boiling points are beneficial, whereas retrogressive reactions, which yield higher molecular weight compounds that are refractory to further processing, give lower yields of desired products. The objectives of this research are to determine the process conditions that give rise to retrogressive reactions during preconversion processing and to identify methods for minimizing the occurrence of these reactions. Initial studies have been performed using dibenzyl ether as a compound to model ether linkages in coal. Results show that retrogressive reactions can occur at temperatures as low as 180{degree}C. The presence of a good hydrogenation catalyst and a hydrogen donor was found to minimize retrogressive reactions, whereas the presence of mineral matter, primarily clay minerals, and ZnCl{sub 2}, enhanced the reactions. 8 refs., 3 figs.