U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038, USA.
Bioresour Technol. 2010 Jun;101(12):4403-8. doi: 10.1016/j.biortech.2010.01.092. Epub 2010 Feb 11.
Removal of ethanol from the fermentor during fermentation can increase productivity and reduce the costs for dewatering the product and coproduct. One approach is to recycle the fermentor contents through a stripping column, where a non-condensable gas removes ethanol to a condenser. Previous research showed that this approach is feasible. Savings of $0.03 per gallon were predicted at 34% corn dry solids. Greater savings were predicted at higher concentration. Now the feasibility has been demonstrated at over 40% corn dry solids, using a continuous corn liquefaction system. A pilot plant, that continuously fed corn meal at more than one bushel (25 kg) per day, was operated for 60 consecutive days, continuously converting 95% of starch and producing 88% of the maximum theoretical yield of ethanol. A computer simulation was used to analyze the results. The fermentation and stripping systems were not significantly affected when the CO(2) stripping gas was partially replaced by nitrogen or air, potentially lowering costs associated with the gas recycle loop. It was concluded that previous estimates of potential cost savings are still valid.
发酵过程中从发酵罐中去除乙醇可以提高生产力，并降低产品和副产物的脱水成本。一种方法是通过汽提塔回收发酵罐内容物，其中不可冷凝气体将乙醇去除到冷凝器中。先前的研究表明，这种方法是可行的。在 34%的玉米干固体时，预计每加仑节省 0.03 美元。在更高的浓度下，预计会有更大的节省。现在，使用连续玉米液化系统，在超过 40%的玉米干固体时已经证明了其可行性。一个试验工厂，每天连续进料超过一蒲式耳（25 公斤）的玉米粉，连续运行了 60 天，连续转化了 95%的淀粉，生产了 88%的最大理论乙醇产量。使用计算机模拟分析了结果。当 CO(2)汽提气体部分被氮气或空气替代时，发酵和汽提系统没有受到显著影响，这可能降低了与气体回收循环相关的成本。结论是，先前对潜在节省成本的估计仍然有效。
