New Technology of Producing Sugar by Acid Hydrolysis of Corn Straw

Objective The aim of the study was to develop the new technology of acid hydrolyzing and saccharifying of corn straw,so as to solve the problem of low yield of acid hydrolysis and saccharifying in the technique of producing ethanol from biomass.Method The hydrolysis and saccharifying law and technology conditions in concentrated and diluted acid stages of two-stage acid hydrolysis was examined by single factor and orthogonal experiments.Two-stage method of combining the pretreatment with concentrated acid and hydrolysis with diluted acid was used to hydrolyze corn straw and the hydrolysis condition was optimized.Result It was preliminarily confirmed that the superior conditions of hydrolysis technology for two-stage acid hydrolysis under normal pressure were as follows:Acid concentration of 60 %,ratio of acid to solid of 12:1,hydrolysis time of 0.5 h and temperature of 45 ℃ in the first stage of pretreatment with concentrated acid;ratio of water to solid of 220:1,hydrolysis time of 2.0 h and hydrolysis temperature of 100 ℃ in the second stage of hydrolysis with diluted acid,under which the total sugar yield in the hydrolyzate could be up to 93.81 %.The total sugar yield increased significantly through two-stage hydrolysis.Conclusion The technology of two-stage acid hydrolysis under normal pressure was put forward at the first time.It has advantages of moderate condition,simple flow,low cost,high total sugar yield and broad application prospect.