Methods for extracting xylose liquid and cellulose with high purity from corn straw

A method for extracting xylose liquid and cellulose with high purity from corn straw, comprising:

• step 1, raw material screening including:
• selecting the corn straw with a moisture content of 7%-13%;
• step 2, raw material preprocessing including:
• processing the corn straw into powder using a pulverizer, a particle size of the powder being between 60 mesh and 300 mesh, and then putting the powder into a blower drying box and drying at 45° C. for 22 h-26 h to obtain absolutely dry powdered corn straw;
• step 3, alkali processing including:
• after mixing the absolutely dry powdered corn straw with process water, adding 30% concentrated alkali liquid and adjusting a concentration of NaOH in the system to 0.1%-0.4%, performing the alkali processing for 1.2 h-2.0 h under a temperature of 85° C.-125° C., then obtaining straw residue and a centrifugal clear liquid by centrifugal separation, wherein the straw residue enters a xylose extraction process;
• step 4, acid hydrolysis including:
• mixing the straw residue with a 1.0%-2.5% dilute H2SO4 solution in a certain proportion, performing the acid hydrolysis at 100° C.-160° C. for 30 min-120 min, and then performing a centrifugation to obtain an acid hydrolyzed liquid and acid hydrolyzed straw residue, wherein the acid hydrolyzed liquid is a high-purity xylose liquid, and the acid hydrolyzed straw residue enters a following cellulose extraction process;
• step 5, gradient alkali processing including:
• after mixing the hydrolyzed straw residue and the process water, adding 30% concentrated alkali liquid and adjusting a concentration of NaOH in the system to 0.2%-1%, performing preprocessing continuously for 4.0 h-7.0 h, wherein an initial temperature is 60° C.-90° C., then for every 1 hour, increasing the concentration of NaOH by 0.1%-0.5% and increasing the temperature by 10° C.-20° C., after separating the treated material by centrifugation, washing a solid portion to obtain a high cellulose content product.