A new approach to design heat-integrated reactive distillation process: Part 2. Role of additional variable in excess design

• Novel energy saving approach for heat-integrated excess design RD processes. • Targets on minimizing energy consumption of RD column before heat integration. • Excess design introduces additional degree of freedom. • X LLK-R is a key design variable for optimizing excess design RD processes. • Novel approach achieves energy savings of over 27.55% for RD and TCRD. The purpose of this paper is to explore the possibility of extending a new perspective previously identified for neat design (DOI: 10.1016/j.seppur.2024.131201 ) to the excess design of reactive distillation (RD) configurations. In earlier research, we proposed to minimize the energy consumption of the RD column (RDC) prior to heat-integration (HI), instead of the conventional method of minimizing overall energy consumption, to achieve a more significant energy savings. This study extends the investigation to two specific configurations, i.e., excess design (1) RD and (2) thermally coupled reactive distillation (TCRD). The purpose of exploring such extension is because the excess design of RD is different from those of neat design due to the additional degree of freedom (DOF) available, such as the purity of recycled component. Our findings revealed that, minimizing the energy consumption of RDC results in higher energy savings for excess configurations. Post HI, the excess design RD and TCRD achieved energy savings of 27.65% and 27.55%, respectively, compared to the conventional RD base case. Furthermore, our study highlights the importance of considering X LLK-R as a design variable when performing process optimization for excess design.