A Generalized Pinch Technology Approach for Optimal Design of Vapor Recompression Distillation Columns

Many countries have established targets such as achieving 100% carbon-pollution-free electricity by 2035 and net-zero greenhouse gas emissions by 2050. The U.S. Long-Term Strategy outlines various pathways toward achieving a net-zero economy by 2050, with a particular focus on the electrification of process heat in industries for chemical production. Among the proposed methods, heat-pump-assisted vapor recompression distillation columns (VRC) have gained attention as a sustainable alternative for distillation process design. Different researchers have proposed and analyzed a variety of VRC configurations primarily based on their experience. The existing approach does not provide any insights into the economic viability of using VRC as an alternative to conventional distillation nor does it identify the optimal configuration. This work proposes a novel systematic design methodology to determine the minimum achievable utility cost for a VRC process prior to design. The proposed method effectively leverages pinch analysis embedded within an optimization framework to obtain the optimal VRC configuration. The application of the proposed method for the separation of propane/propylene and benzene/toluene mixtures shows that VRC configurations with significantly lower utility costs can be obtained compared with the existing configurations in the literature. The proposed approach can potentially be extended for the optimal design of other work-heat-integrated processes.