Comparative investigation on the pyrolysis of crop, woody, and herbaceous biomass: Pyrolytic products, structural characteristics, and CO2 gasification

Abstract

Pyrolysis and gasification are efficient clean energy conversion technologies used in energy research. Clean utilization of biomass energy can effectively alleviate severe energy challenges in the world. In this study, wheat straw, peach wood, and bamboo were pyrolyzed in a quartz tube furnace, and the pyrolysis gas production and physical and chemical properties of the char products were analyzed systematically. The CO2 gasification performance of the pyrolyzed char was investigated experimentally. The results indicated that the pyrolysis temperature had a significant effect on char properties. A high pyrolysis temperature accelerates the gas release rate and improves the final gas production. As the pyrolysis temperature increased, the quality of the char decreased, and the O/C and H/C molar ratios of the biomass char decreased gradually. The char calorific value was also affected by the temperature. The Fourier Transform Infrared Spectroscopy (FTIR) results demonstrated that the functional groups of the biomass decomposed. Scanning Electron Microscope (SEM) images indicated that as the pyrolysis temperature increased, pore development expanded, and various folds appeared on the surface. The fractal box dimensions first increased and then decreased. The specific surface area and micropore volume of the char first increased and then decreased; however, the temperature at which the peak value occurred was slightly different. In the gasification experiment, the peach wood char prepared by pyrolysis at 600 °C had a superior gasification effect. Biomass with a lower ash content, higher O/C ratio, and more developed pore structure exhibited superior gasification performance. The conclusions of this study have important reference value for large scale, clean, and efficient utilization of biomass resources.