| Popis: |
Studies of Illinois No. 6 coal in CO/water at 400°C over a range of conversions to toluene-soluble (TS) products show product yields in D2O consistently superior to those in H2O, the yields leveling off respectively at 60% and 50%. These findings are compelling toward a conversion scheme in which coal is partitioned in parallel, competitive steps to TS and toluene insoluble (TI) fractions, with the TS/TI ratio determined by the reduction potential of the system. Conversion is thus limited by the kinetics of conversion rather than by coal structure, this limitation applying to conversion generally, including conventional donor conversions. The CO/water system has been successfully modeled with a numerical simulation scheme on a microcomputer, the model showing that the key limiting feature of the CO/water system is irreversible consumption of OH− by CO2. The major source of CO2 is the water gas shift reaction, which operates in parallel to the conversion chemistry. |
