Integrating vapor recompression heat pump into n-propyl acetate reactive distillation process for decarbonization and performance enhancement

Abstract

Vapor recompression technique (VRC) is one of the crucial strategies for process electrification and decarbonization within the New Industry 4.0 paradigm. This work explores the application of VRC, involving the novel intermediate reboiler (IR)-assisted VRC configuration, in the reactive distillation system for n-propyl acetate (PrAc) synthesis via transesterification of methyl acetate (MeAc) and n-propanol (PrOH). The conventional reactive distillation process (CRD), composed of a wide-boiling RD column and a sequential distillation column, is highly energy-intensive due to the existence of azeotropes. Process alternatives, incorporating double-effect distillation (DE), VRC and VRC-IR technologies, are proposed to save energy. In the optimization of the VRC-IR-assisted processes, the effects of crucial parameters, such as the side stream locations, the duty that associated with the IR and the compression ratio, on process intensification are discussed. The processes proposed are subsequently evaluated in terms of economic, environmental, and thermodynamic perspectives. Both VRC-assisted flowsheets demonstrate superior performance over the CRD and RD-DE cases. The RD-VRCIR-VRC, simultaneously intensifying VRC-IR and VRC in the two separate columns, emerges as the most efficient option, showcasing remarkable reductions of 48.16 % in TAC, 79.92 % in CO₂ emissions and significant improvement of thermodynamic efficiency by 92.79 % compared with the CRD design.