Separation Strategies of Hydrogenation and Oxidation Products from Miscanthus for Bio-Ethylene Glycol Production

Miscanthus can be hydrogenated into ethylene glycol (EG), or can be oxidized into methyl glycolate (MG), a precursor of EG. For comparison, three-, two-, and four-column processes (I, II, and III, respectively) were established for the separation of hydrogenation (I) and oxidation products (II and III) in ASPEN PLUS. The processes II and III treated oxidation products containing negligible and appreciable amounts of methyl levulinate (MLE), respectively. The total heat duty (THD) and total cold duty (TCD) of process I were approximately 73% lower than those of processes II and III, and the E-factor of process I was relatively low, but the maximum operation temperature (MOT) was high. Process II (esters hydrogenation first) was both energy-saving and cost-effective because of low high-temperature heat duty (HTHD), less EG loss, and low total annual cost. Process III (esters distillation first) exhibited the largest THD, TCD, HTHD, and total annual cost. Sensitivity analysis results demonstrated that MLE gr...