Energy Efficiency Improvement in a Modified Ethanol Process from Acetic Acid

For the high utilization of abundant lignocellulose, which is difficult to directly convert into ethanol, an energy-efficient ethanol production process using acetic acid was examined, and its energy saving performance, economics, and thermodynamic efficiency were compared with the conventional process. The raw ethanol synthesized from acetic acid and hydrogen was fed to the proposed ethanol concentration process. The proposed process utilized an extended divided wall column (DWC), for which the performance was investigated with the HYSYS simulation. The performance improvement of the proposed process includes a 27% saving in heating duty and a 41% reduction in cooling duty. The economics shows a 16% saving in investment cost and a 24% decrease in utility cost over the conventional ethanol concentration process. The exergy analysis shows a 9.6% improvement in thermodynamic efficiency for the proposed process.