A novel economical reactive distillation with two reaction sections for separating isobutene in C4 to save energy and reduce CO2 emissions

In this study, the conventional reactive distillation (RD) process and the reactive distillation with two reaction sections (RD-TRS) are proposed to separate isobutene from C4. The arrangement of RD-TRS strengthens reaction and distillation processes, and reduces the operation cost and capital investment. Because the temperature between the top and bottom of the RD-TRS column is less than 15 ℃, the vapor recompression heat pump technology can be applied. Hence, the heat pump reactive distillation with two reaction sections (HRD-TRS) is proposed. Finally, the three processes are optimized with the minimum total annual cost (TAC) as the evaluation indicator. The results show that, compared with RD, CO2 emissions of RD-TRS and HRD-TRS processes decreases by 16% and 21%, respectively; TAC of RD-TRS and HRD-TRS decreases by 19.7% and 52.7%, respectively; TEC of RD-TRS and HRD-TRS decreases by 21.6% and 75.5%, respectively. The thermodynamic efficiency increases from 18% for RD, to 19% for RD-TRS, and 22% for HRD-TRS.