화학공학소재연구정보센터
Energy & Fuels, Vol.33, No.12, 12527-12537, 2019
Nonisothermal Thermogravimetric Kinetic Investigations on Combustion Behaviors of Concomitant Biomass from Urban Plants
Thermogravimetric combustion characteristics of white poplar leaves, pine needles, poplar leaves, ginkgo leaves, and corn straw in air were tested under different heating rates. The results indicated that the combustion process of biomass consisted of at least two independent reactions, while the number of reactions was related to the properties of components in biomasses. In addition, the corresponding temperature of the maximum reaction rate on reaction rate curves shifted into higher temperature zones with increasing heating rate, which was due to the insufficient transfer of heat under a high heating rate. Meanwhile, the reaction rate curves were separated into independent peaks and then fitted with three kinetic models. It was found that the combustion of biomass samples followed the volume model in the early stage and then obeyed the random pore model in the last stage. Namely, the influence of thermodynamic conditions is more significant for the pyrolysis of selected biomasses, while the combustion of residual carbon depends on kinetic conditions. Moreover, the evolution of functional group structures in biomasses during combustion showed that aliphatic hydrogen and C=C bands were stable at the early stage, while aromatic hydrogen was observed to be more stable during the whole combustion process. The fluctuation in proportion of -CH3 was insignificant for new radicals of -CH3 that were formed during the decomposition of aromatic and aliphatic hydrocarbons; however, the overall decreasing trend indicated the gradual shrink in length of aliphatic branches with the extending of combustion.