Multi-objective optimization for carbon footprint reduction of a novel pressure-swing distillation process integrating heat pump and solar energy for methyl tert-butyl ether/methanol separation

Methyl tert-butyl ether (MTBE) is an important chemical feedstock and fuel additive with significant applications in the chemical and petrochemical industries. However, the MTBE production process often forms an MTBE/methanol (MeOH) azeotrope, making separation challenging. In previous work, we proposed an effective extractive distillation separation process. This work aims to develop an alternative, highly efficient pressure-swing distillation (PSD) process. First, based on thermodynamic analysis, two conventional PSD processes were proposed and optimized to minimize the total annual cost (TAC) and CO2 emissions while maximizing thermodynamic efficiency. Subsequently, eight intensified separation processes incorporating heat integration, vapor recompression heat pump, and solar energy were designed. Finally, the comprehensive performance of all schemes was evaluated from economic, environmental, energy, and exergy (4E) perspectives. Results indicate that PSD2 outperforms PSD1, with the dual heat pump-solar energy intensified sequence (PSD2-HP-SE) being the optimal scheme, achieving reductions in TAC, CO2 emissions, total energy consumption, and exergy loss by 49.34 %, 100 %, 100 %, and 72.61 %, respectively, and an increase in thermodynamic efficiency by 68.17 %.