Influence of Crop Residue Types on Microwave-Assisted Liquefaction Performance and Products

Microwave-assisted polyhydric liquefaction of crop residues was a useful method for the conversion of lignocelluloses into biopolyols. Five types of crop residues were selected to investigate the effect of feedstock varieties on the microwave-assisted liquefaction performance and products. The microwave-assisted liquefaction characteristic of different feedstocks in ethylene glycol (EG) was evaluated by residue component analysis and kinetics modeling. Cellulose was proven to be the main residual content, and hemicelluloses and lignin were liquefied rapidly. According to the first-order model, degradation of cellulose was indicated to be the rate-determining step in the microwave solvolysis liquefaction of crop residues. Among the five types of crop residues, rice straw was the material most difficult to be liquefied. Acid-insoluble ash (AIA) was found to be significantly negatively correlated with the liquefaction rate of crop residues and cellulose. The hydroxyl number and acid number of microwave-assisted liquefaction products (MLPs) from different feedstocks varied with different crop residues.