Energy-saving strategy for separation of methylcyclohexane/tert-butanol azeotrope

Abstract

With the increase in industrialization, researchers are striving to pursue energy-saving and environment-friendly separation technologies. In this regard, effective separation of azeotropes is one of the focus areas in recent years. According to the characteristics of methylcyclohexane (MCH) and tert-butanol (TBA) azeotropes, a pressure-swing distillation (PSD) process is established in the current work. Combined with steam recompression and heat integration, two improved separation processes for reduced energy consumption are designed. The operating parameters had a significant effect on the efficiency and cost of the process. Therefore, the selection of parameters was discussed in detail. The proposed PSD processes were evaluated according to the assessment indices including total energy consumption (TEC), CO2 emissions and total annual cost (TAC). The results showed that the improved processes obviously decreased the energy consumption and improved the economy whether it is heat pump pressure swing distillation (HP-PSD) or heat integrated pressure swing distillation (HI-PSD). The HI-PSD process can achieve a TAC savings of 30.86%, TEC reduction of 37.59% and CO2 reduction of 36.34%. The HP-PSD process is found to be the most economical and environment-friendly process among the studied processes, and could achieve 34.92% TAC savings, 42.89% TEC reduction and 50.98% CO2 reduction.