Feasibility study of heat-integrated distillation columns using rigorous optimization

In this work, rigorous optimization of HIDiC (Heat-Integrated Distillation Column) and VRC (Vapor Recompression Column) is implemented by GA (Genetic Algorithm) to find an alternative for CDiC (Conventional Distillation Column). The objective function is TAC (Total Annual Cost). Three different case studies are investigated, being composed of benzene-toluene, propane-propylene, and methanol-water. A novel strategy is proposed to consider all the heat integration possibilities resulting in more efficient search space than our previous attempt. It is observed that the heat exchangers arrangement of optimum HIDiCs are very similar to VRCs in ideal case studies. Although CDiC is the optimum configuration in the benzene-toluene separation, 6.6% reduction is achieved for the presented HIDiC compared to previous work. For propane-propylene splitter, VRC is the economical alternative with a 44.1% decrease in the TAC of CDiC. Moreover, VRC and HIDiC optimizations leads to 25.5% and 4.4% reductions in TAC compared to previous work, respectively. However, for the non-ideal methanol-water separation, which has a wide boiling point range, the TAC of optimum HIDiC is surprisingly lower than CDiC and optimum VRC by 3.4% and 31.2%, respectively.