Implementation of an ideal-system energy-saving strategy to non-ideal double-effect reactive distillation

The applicability of a column-specific design strategy, previously developed for an ideal reaction in double-effect heat-integrated reactive distillation (RD) was evaluated for non-ideal reaction systems. The transesterification of methyl acetate (MEAC) and butanol (BUOH), a system exhibiting azeotropic behavior, was used as the case study. The strategy was implemented using a two-stage optimization for RD and a single-stage optimization for thermally coupled RD (TCRD). Both the heat-integrated RD and a hybrid configuration combining thermal coupling with double-effect heat integration (HI) were examined. The performance of the column-specific strategy, which prioritized minimizing the reboiler duty of the heat-supplying column (i.e., the reactive distillation column (RDC)), was compared with the conventional approach that minimized total energy consumption. Results showed that the column-specific strategy achieved an energy savings of 28%, total annual cost (TAC) reductions of up to 20%, and CO 2 emission reduction of 28% after HI, relative to the RD base case. It was also found that while thermal coupling reduced remixing, it did not always sufficiently lower the RDC energy demand to outperform the double-effect RD configuration. Overall, the findings demonstrated the applicability and benefit of the column-specific strategy for designing energy-efficient, cost-effective and environmentally friendly heat-integrated RD process under non-ideal conditions.