Research on Quality Control of Rice Straw Based on Low Temperature Torrefaction Pretreatment
To meet the needs of biomass-oriented depolymerization and value-added pretreatment technology,rice straw(RS)was taken as the raw material.To explore the mechanism of thermochemical coupling for physical quality control,the chemical composition,thermal stability,crystallinity,and functional group types of RS after low-temperature torrefaction were analyzed using thermogravimetric(TG)analysis,X-ray diffraction(XRD),and Fourier transform infrared spectroscopy(FT-IR).The results showed that the crystallinity of RS increased slightly and then decreased at 120,160 and 200 ℃,with crystallinity of 35.45%,36.03%,and 32.42%,respectively.Compared to RS-180,under the torrefaction condition of 200℃,the content of cellulose decreased by 1.59 percentage points,while hemicellulose and lignin content increased by 1.35 percentage points and 1.73 percentage points,respectively.Under the torrefaction condition of 200℃,the weight loss of RS was 12.79%.Compared to RS,the maximum degradation rate of RS-200 at the sharp peak of cellulose weight loss increased from 15.81 to 17.11%/min,indicating improved thermal stability.Furthermore,compared to untreated RS,the total acid groups increased by 9.04%,carboxyl groups decreased by 33.33%,and phenolic hydroxyl groups increased by 105.56%.The equilibrium moisture content decreased from 11.56%to 8.20%,and the hydrophobicity improved.
low temperature torrefactionchemical compositioncrystallinityoxygen-containing functional groupshydrophobicity