Synthesis and Integrated\nDesign of a Compact Azeotropic\nProcess for EtAc–MeOH–Water Separation

This study presents the synthesis and design of a two-column\ncompact\ndistillation (CD) process for separating a dilute ethyl acetate (EtAc)–methanol\n(MeOH)–water mixture, which has two minimum boiling azeotropes,\ninto its constituent (nearly) pure components. The synthesized flowsheet\nleverages the pressure sensitivity of the azeotropes as well as the\nliquid–liquid phase split for efficient separation. To improve\nthe energy efficiency, the basic flowsheet, consisting of a decanter,\na high-pressure simple column, and a low-pressure divided-wall column,\nis heat-integrated (HI) using external heat exchangers to obtain the\nHI-CD process. The most energy-efficient hybrid-CD process is obtained\nby incorporating vapor recompression-driven reboil in the two columns\nalong with external process-to-process heat exchange. A quantitative\ncomparison with the recently reported best design, namely, the hybrid\nheterogeneous triple-column distillation (HTCD) process, reveals substantial\neconomic and sustainability advantages of the proposed hybrid-CD process\ndesign. Specifically, the total annualized cost of the hybrid-CD process\nis lower by 15.4% compared with the hybrid-HTCD process. Energy consumption\nand <i>CO</i><sub>2</sub> emission are also significantly\nlower by 34.3 and 31.4%, respectively.