Synthesis and Integrated Design of a Compact Azeotropic Process for EtAc-MeOH-Water Separation

This study presents the synthesis and design of a two-column compact distillation (CD) process for separating a dilute ethyl acetate (EtAc)-methanol (MeOH)-water mixture, which has two minimum boiling azeotropes, into its constituent (nearly) pure components. The synthesized flowsheet leverages the pressure sensitivity of the azeotropes as well as the liquid-liquid phase split for efficient separation. To improve the energy efficiency, the basic flowsheet, consisting of a decanter, a high-pressure simple column, and a low-pressure divided-wall column, is heat-integrated (HI) using external heat exchangers to obtain the HI-CD process. The most energy-efficient hybrid-CD process is obtained by incorporating vapor recompression-driven reboil in the two columns along with external process-to-process heat exchange. A quantitative comparison with the recently reported best design, namely, the hybrid heterogeneous triple-column distillation (HTCD) process, reveals substantial economic and sustainability advantages of the proposed hybrid-CD process design. Specifically, the total annualized cost of the hybrid-CD process is lower by 15.4% compared with the hybrid-HTCD process. Energy consumption and CO 2 emission are also significantly lower by 34.3 and 31.4%, respectively.