Novel Solvent Exchange Distillation Process- a Comparison Study with Batch Systems

A novel solvent exchange distillation process for both zeotropic and azeotropic equilibrium, which has been developed for replacement of one solvent with a second solvent while keeping the concentration of dissolved nonvolatile solute constant, is described. Detailed simulations for methanol or ethanol replaced by water show that solvent to feed ratios near 1.0 are often sufficient. Comparison of the results with detailed batch distillation simulations show that the novel solvent exchange method gives the same purity with lower solvent and energy consumption. When the less volatile solvent has to be replaced with a more volatile solvent, batch distillation, which requires very large amounts of added solvent and of energy, would normally not be used. Thus, the new solvent exchange distillation process represents a totally new approach to this exchange problem.