Effects of Torrefaction on the Pyrolysis Behavior and Bio-Oil Properties of Rice Husk by Using TG-FTIR and Py-GC/MS

The properties of biomass directly result in the quality of bio-oil. Torrefaction pretreatment is an alternative and promising approach for biomass updating to produce high-quality bio-oil. The effects of torrefaction on the pyrolysis of rice husk were investigated using thermogravimetry–Fourier transform infrared spectroscopy (TG-FTIR), a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and a fast pyrolysis device. The results show that with increasing torrefaction temperature, the weight loss decreases and the shoulder peaks of torrefied rice husk in DTG curves fade away. The pyrolysis characteristics and kinetics analysis of torrefied rice husk at 290 °C are unique. Three-dimensional FTIR analysis of the evolved gases clearly shows the generation properties of individual volatile components. Fast pyrolysis of torrefied rice husk produces improved bio-oil low moisture content and high heat value. Py-GC/MS analysis shows that the acidic content does not increase, while the content of many highly valued products (e.g., levoglucose) increases greatly.