Exergy analysis and optimization of reactive distillation column in acetic acid production process

Exergy analysis method is applied to evaluate the performance of reactive distillation (RD) column in the acetic acid production process, at which acetic acid is produced via reaction between carbon monoxide and methanol with a soluble catalyst system consisting of rhodium complex (catalyst) and methyl iodide-hydrogen iodide (promoter). In this column, desired purity of the product is obtained through reaction between methanol and hydrogen iodide. The effects of different operational parameters on the separation and the exergy efficiencies of this RD column are evaluated by sensitivity analysis, finally, the response surface methodology (RSM) method is applied for modeling and optimization of the exergy loss. The adequacy of the developed model for exergy losses in the reactive distillation column is evaluated using analysis of variances (ANOVA). The result of ANOVA study shows that the most effective operating parameters are feed stream temperature, boilup ratio, and reflux ratio. As the result of this optimization the exergy losses and energy consumption for the reactive distillation column reduced by 28% and 12% respectively. This study shows that RSM method besides the exergy concept could be an appropriate tool for optimization of complex and energy intensive reactive distillation systems.