Salting-and Sugaring-out Extraction Of Ethanol From Fermentation Broths

Ethanol is a promising chemical, which can be used as a variety of chemical feed stocks. It is an important clean fuel as an alternative to fossil fuels. It also has been used in other ways, such as paint, medicine, cosmetics, personal-care products and oil. The main ways to separate ethanol from fermentation broths are distillation and rectification. But those ways consume too much energy, and the cost of distillation and rectification accounts for8%-15%of total cost of ethanol production. To solve those problems, salting-out extraction and sugaring-out extraction were adopted to separated ethanol from fermentation broths in this article.Firstly, hydrophobic organic solvent/salt extraction was investigated to separate ethanol from the fermentation broth. And n-butanol/sodium carbonate system was selected for the further study. The effect of component concentration and product concentration on the extraction were studied. Under the optimum conditions, recovery of ethanol was over92%. Then, carbon dioxide was used to recover the sodium carbonate in the bottom phase. We recovered the carbonate decahydrate from n-butanol/sodium carbonate system successfully, and the removal ratio of sodium carbonate reached81%.Secondly, hydrophobic organic solvent/sugar extraction was studied to separate ethanol from the fermentation broth. And n-butanol/glucose system was selected for the further research. The effect of component concentration and product concentration on the extraction were investigated. Under the optimum conditions, recovery of ethanol was over60%. Soon after, we tried to use carbon dioxide to dislodge the n-butanol in the bottom phase, and the residual n-butanol was less than7g/L.Lastly, we studied the bottom phase in the n-butanol/glucose system trying to couple the ethanol production and separation. Besides, we researched the effect of different constituents on ethanol fermentation.Generally speaking, the salting-out extraction and sugaring-out extraction would be two potential skills for industrial production because of the simple craft, magnifying easily. And the two ways are easily to couple with the ethanol production. Although there are still many problems to overcome, they would be two potential forefront techniques for industrial application.