Effect of hydrothermal carbonization on woody biomass: From structure to reactivity

Hydrothermal carbonization (HTC) pretreatment is an effective method to upgrade the low quality biomass properties. In this work, the pinewood (PIW) and poplar wood (POW) were selected to study the effect of HTC (180-240 degrees C) on woody biomass structure and reactivity. The results showed that the slight and moderate HTC can make the cellulose structure more ordered, while the severe HTC leaded to the decomposition of cellulose structure. The mesoporous specific surface area and pore volume increased with the HTC temperature, and the pore structure of PIW was more developed than that of POW. The slight HTC had little effect on cellulose structure and the diffusion effect played the dominant role. The severe HTC increased the relative content of lignin and the pyrolysis followed the high order reaction model. The model-free method was used to determine the relationship between T-beta-X, and the specific temperature T-HTC/T-raw was calculated. The T-HTC/T-raw value of PIW and POW located in the range of 0.938-1.340 and 0.924-1.422, indicating the HTC pretreatment had great effect on POW pyrolysis reactivity.

Automated summary

Hydrothermal carbonization (HTC) pretreatment was conducted on pinewood and poplar wood to investigate its effect on woody biomass structure and reactivity. The results showed that slight and moderate HTC improved cellulose structure, while severe HTC led to cellulose decomposition. The increase in HTC temperature resulted in higher mesoporous specific surface area and pore volume, with pinewood showing more developed pore structure. HTC had little effect on cellulose structure under slight HTC, with diffusion playing a dominant role. Severe HTC increased lignin content and followed a high order reaction model during pyrolysis. The T-HTC/T-raw values for pinewood and poplar wood ranged from 0.938 to 1.340 and 0.924 to 1.422, indicating significant effects of HTC pretreatment on poplar wood pyrolysis reactivity.