Effects of pelletizing conditions on the structure of rice straw-pellet pyrolysis char

The pyrolysis char structure affects gasification reactivity. In this study, the effects of pelletizing conditions on the structural characteristics of straw-biomass-pellet fast pyrolysis char were investigated. Agricultural rice straw was used to prepare cylindrical pellets having a diameter of 8 mm. Pyrolysis at 600 degrees C was carried out in a fixed-bed reactor. The porosity, pore structure, and carbon crystalline structure of the pyrolysis char were analyzed using the Brunauer-Emmett-Teller (BET) method and Raman spectroscopy. The results demonstrated yield of pellet pyrolysis char is significantly greater than that of raw biomass, with more mesopores and fewer macropores present in the pellet pyrolysis char. Additionally, the char yield of the pellets made of < 88 mu m straw particles was higher than that of the pellets with other particle size ranges. The pellet char had the largest specific surface area and showed greater carbon disorder when the biomass particle size was 150-250 mu m. Moreover, the effects of pelletizing pressure on char yield, porosity, and carbon structure were insignificant.