EFFECT OF SOLVENT-TO-COAL RATIO ON ORGANOSULFUR EXTRACTABIL1TY IN THE PERCHLOROETHYLENE ORGANODESULFURIZATION PROCESS

A novel reaction-extraction model for removal of organosulfur compounds from coal by the Perchloroethylene Organodesulfunzation Process has been proposed. The model treats the coal as a reactant to observe the effect of slurry composition on the rate of “lock-up” reaction where the liberated organosulfur species from coal re-enters the coal organic matrix. A series of batch organodesulfunzation extractions were conducted to observe the effect of solvent-to-coal ratio on the extent of organosulfur removal. Based on this data, kinetic parameters for the organosulfur “liberation” and “lock-up” reactions were simulated using the model. The ratio of first-order rate constant of “lock-up” reaction to that of the “liberation” reaction was found to be 4.03. Optimal design parameters and operating conditions have been obtained for a wide range of PCE-to-coal ratio for Indiana 5 coal. Mathematical models representing the optimal slurry composition as a function of the ratio of rate constants, extraction capacity, and the corresponding extraction performance have been developed. This study is very significant from the point of view of reaction and process engineering, which in turn assist in achieving an optimal and economical equipment design.