Eco-efficiency analysis and intensification of the monochlorobenzene separation process through vapor recompression strategy

Abstract

Monochlorobenzene is widely used in producing herbicides, pesticides, and pharmaceuticals and, despite its toxicity and lack of a green substitute, has significant commercial influence. Thus, process intensification can enhance the purification process's sustainability performance. Recently, a double-effect distillation with heat integration (DEDHI) scheme was proposed to intensify an industrial-scale monochlorobenzene separation plant. As a continuation, this work proposes another strategy based on heat integration and vapor recompression (VRHI). A utility plant was considered for realistic outcomes regarding water consumption, CO₂ emissions, and utility costs, grouped to represent the process's eco-efficiency. The total annualized cost (TAC) criterion was also contemplated. The comparison showed that DEDHI and VRHI are 84.57 % and 96.21 % more eco-efficient than the conventional process, respectively. The DEDHI design is more economically attractive, reducing TAC by 21.40 % for a 3-year payback period. In contrast, the VRHI scheme is more environmentally friendly, reducing CO₂ emissions and water consumption by 73.32 % / 94.08 % (United States / Brazil locations) and 84.87 %, respectively. However, VRHI is only economically attractive for a 10-year payback period, with TAC savings of 18.10 % compared to the conventional process, mainly due to the high capital expenditure for the two-stage compressor and the electricity cost.