Tuesday, April 30, 2013
Exhibit Hall
Ethanol production from lignocellulosic materials is coming closer to a commercial deployment but several challenges must still be addressed aiming to improve process performance and economics when compared to ethanol from sugar/starch (1G). The well-known challenge in the transformation of lignocellulosic material via enzymatic process is the pretreatment, which deeply affects the following steps mainly due to cellulose convertibility and inhibitors production. Among the factors determining the minimum 2G-ethanol selling price, ethanol concentration prior to distillation has a large impact both on energy demand and capital cost. Two strategies pursued to achieve higher ethanol concentration consist in increasing the solids load (WIS) during enzymatic hydrolysis and fermentation, or in recirculating the liquid fraction of the fermented broth before enzymatic hydrolysis. However, the main drawback as a result of those strategies is a potentially highly toxic broth, which is difficult to ferment by the traditional baker’s yeast Saccharomyces cerevisiae, yielding a lower productivity. In this study the techno-economic issues are assessed for a 1G+2G ethanol production plant from sugarcane, focusing on the effect of detoxification on energy efficiency and minimum 2G-ethanol selling price. The thermodynamic and economic calculations are carried out in the AspenPlus platform and the input regarding enzymatic hydrolysis, fermentation and detoxification are based on data obtained from laboratory experiments. Results from this work are also compared to previous studies and contextualised in the panorama of options which aim to make ethanol an attractive fuel. An insight of market potential and profit is provided as well.