Process simulation and optimization on phenol extraction for coal-gasification wastewater

Coal-gasification wastewater is an industrial toxic wastewater with high concentration of phenols. To provide process parameters for industrial practice, simulation and optimization were carried out on the phenol removal process for coal-gasification wastewater which included phenol extraction, solvent distillation and residual solvent stripping. Calculation results showed that the optimized process parameters were as the following. When solvent ratio was 1:6, after four-stage extraction by methyl isobutyl ketone, the concentration of phenols in the wastewater can be reduced to below 200mg/L from 5000mg/L. While in the solvent distillation column, to make the solvent recycling usable and cut down solvent consumption, the column stages was recommended as 15, reflux ratio R as 0.1360, and feed stage as 10. Moreover, to recover the residual solvent in the wastewater, the number of theoretical stages for the stripper was proposed as 5, and distillate rate as 2388kg/hr.