Method for preparing cellulosic ethanol through alkali pretreatment

Abstract

The invention relates to a method for preparing cellulosic ethanol through alkali pretreatment. The technological process comprises the following steps of performing alkali fusion on hemicellulose andlignin, and separating crude cellulose; precipitating oligosaccharide with sulphuric acid to prepare lignin nanometer particles; hydrolyzing oligosaccharide with dilute acid to obtain a xylose solution; performing low-temperature dehydrating and carbon sequestration treatment on the lignin nanometer particles, performing thermolysis, and performing activation so as to obtain lignin based nanometer carbon black; drying the coarse cellulose, hydrolyzing the cellulose with concentrated acid, performing sugar and acid separation, and performing hydrolyzing with dilute acid to prepare a glucose solution; combining the xylose solution with the glucose solution, performing neutralization and precipitation, purifying a sugar solution, and performing fermentation so as to prepare ethanol; and performing rectification to prepare 95% ethanol, and performing mother liquid separation so as to obtain xylose and arabinose.According to the method disclosed by the invention, by an alkaline pretreatment method, the hemicellulose, the lignin and the cellulose are separated; the lignin is used for preparing the nanometer particles or is deeply processed into nanometer carbon black, the purified cellulose is subjected to hydrolyzing by the concentrated acid and fermentation to obtain the cellulose ethanol, the hemicellulose is used for preparing the xylose and arabinose, three large components ofthe biomass are fully utilized, production of three wastes (waste gas, waste water, industrial residues) does not exist, and comprehensive utilization of the biomass is realized.

Description

technical field [0001] The invention belongs to the field of biomass energy chemical industry, and in particular relates to a method for preparing cellulose ethanol through alkali pretreatment. Background technique [0002] When cellulase is used to hydrolyze biomass to produce ethanol, cellulase must be contacted and adsorbed on the cellulose substrate to react, but factors such as the protective effect of lignin on cellulose and the chemical structure of cellulose covered by hemicellulose cellulose is difficult to hydrolyze. Therefore, pretreatment technology serves as a key step in the conversion of lignocellulose into ethanol. For this reason, people have carried out a lot of research and development work on the pretreatment methods of lignocellulosic raw materials, mainly including physical methods, chemical methods, physicochemical methods and biological methods. However, so far, in the whole process flow, the pretreatment process is the least mature, and the cost of...

AI Technical Summary

Problems solved by technology

However, so far, in the whole process flow, the pretreatment process is the least mature, and the cost of pretreatment is the highest

The main reasons are: (1) the loss of cellulose and hemicellulose in the pretreatment process reduces the yield of monosaccharide and wastes resources; (2) there is no comprehensive utilization of lignin, cellulose and hemicellulose in biomass The main components increase the cost of raw materials; (3) pretreatment of wastewater pollutes the environment; (4) impurities are still in the system, resulting in fermentation inhibitors