Improvement Of Ethanol Fermentation With Cycel Gas Stripping

One of the methods for ethanol production is fermentation,but the main problem in fermentation is the inhibition of the ethanol metabolized by the yeast in the process.The most effective method for alleviating product inhibition is separating ethanol in situ,which can improve the efficiency of fermentation,and can also predigest the process of separation and purification.According to the current technology,this article mentions a new type of process using gas which is produced in fermentation for gas stripping used in situ ethanol removal to alleviate product inhibition.The aim is to conquer the disadvantages in the traditional fermentation with gas stripping.The study is mainly based on the characteristics of chemical engineering separation and fermentation engineering to reduce the energy cost for ethanol distillation and the capacity of the liquor wastes,and the final goal is to decrease the cost.Compared to the cycle compress pump used in the traditional gas stripping process,the septum vacuum pump used in the research can stop the yeast being polluted.The whole reaction system is isolated from the outside,so the gas stripping process is safer.In the ethanol separation in situ cell,the circumfluence and multilevel absorb equipment are used to make the separation process more effective,and then the efficiency of gas stripping is improved.Study on the different rate of gas cycle,the result indicates that 50%of ethanol has been stripped after 6h when the gas rate is 0.8m³Â·h^-1.Furthermore,the filler in the separator has been researched to choose the best one.The result indicates that silica gel can absorb more ethanol than molecular sieve,but the separation efficiency of molecular sieve is better than silica gel.Use this cycle gas stripping in the actual ethanol fermentation industry,ethanol concentration in the fermenter can be controlled below 50g·L^-1,so the production inhibition is avoided,and the yeast activeness will be kept.The ethanol yield is 0.461 g(ethanol)·g^-1(glucose),it is 1.055 times to fed-batch fermentation without gas stripping. The ethanol concentration can reach to 231.29g·L^-1,it is 1.857 times to fed-batch fermentation without gas stripping.