Energy considerations for a SSF-based softwood ethanol plant

摘要: Ethanol can be produced from softwood by steam pretreatment followed simultaneous saccharification and fermentation (SSF). However, the final ethanol concentration in SSF step is usually rather low (around 4 wt%) as a result energy demand downstream processing will high. In an effort to reduce consumption various alternatives for part of process were evaluated technical-economic standpoint. With experimental data basis, whole was modelled using commercial flowsheeting program Aspen Plus. The results used subsequent economic evaluation, which performed Icarus evaluator. A base case configuration, consisting three thermally coupled distillation columns multiple-effect evaporation established. For feed containing 3.5% (w/w) step, overall estimated 19.0 MJ/L production cost 4.14 SEK/L (0.591 USD/L). Different considered, such integration stripper with increasing number effects application mechanical vapour recompression step. Replacement anaerobic digestion also considered. Among these alternatives, digester alternative both resulted significantly lower than case, 10.2 9.8 MJ/L, respectively, productions costs 3.82 (0.546 USD/L) 3.84 (0.549