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

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.