Evaluating and optimizing pretreatment technique for catalytic hydrogenolysis conversion of corn stalk into polyol

• Steam explosion coupled with alkali was a better method for corn stalk treatment.
• This method removed 84.16% of hemicellulose and 71.83% of lignin in corn stalk.
• This method had no significant effect on the glucose loss.
• The activity of catalytic hydrogenation in Ni–W2C/CSAC was mainly come from W2C.
• About 72.74% of polyol was converted from pretreated corn stalk using Ni–W2C/CSAC.

A combinative pretreatment technology of steam explosion (SE) and alkali was applied to enhance hydrogenolysis conversion of corn stalk into polyol with Ni–W2C or Fe–Mn–K catalyst. The results showed that treatments corn stalk with 0.4 MPa SE and alkali removed 84.16 wt% of hemicellulose and 71.83 wt% of lignin and thereby increased the cellulose content from 31.54 to 80.41 wt%. But the glucose loss was insignificant during pretreatment. Data from catalytic hydrogenolysis showed that pretreatment corn stalk with 0.4 MPa SE and alkali improved the yield of polyol, and about 20.38 wt% of ethylene glycol and 52.36 wt% of glycerol were produced after catalysis with Ni–W2C/(coconut shell activated carbon, CSAC). Based on the yield of polyol, the catalytic performance of Ni–W2C/CSAC was significantly better than those of Ni–W2C/(coal-based activated carbon) and Fe-Mn-K/(amorphous carbon).