Influence of torrefaction treatment on the pyrolysis and combustion characteristics of tobacco waste

LIANG Miao; LEI Tian; ZHAN Xiaolin; LIU Sikui; ZHANG Xingquan; ZOU Enkai; LIU Yuxuan; ZHOU Ruifang

doi:10.12187/2025.03.008

Abstract：Tobacco waste was selected as the research object,and structural composition analysis and thermogravimetric analysis methods were used to study the influence of torrefaction treatment on its micro-morphology,elemental composition,pyrolysis,and combustion characteristics.The results showed that torrefaction treatment reduced the equilibrium moisture content and oxygen content of the samples while increasing the carbon content.The higher heating value increased from the original 17.15 MJ/kg to 19.05 MJ/kg,which increased the energy density of the samples,facilitating storage,transportation,and thermochemical conversion and high-value utilization of tobacco waste.During torrefaction,tobacco waste underwent obvious dehydration and decarboxylation reactions.As the torrefaction temperature increased,the surface color of the samples gradually darkened,and it gradually turned charcoal-like.SEM observation showed that after high-temperature torrefaction,the tobacco waste had pores on its surface and its microstructure was destroyed.The effect of torrefaction temperature on the pyrolysis process of tobacco waste was significant.This was reflected in the reduction of the weight loss rate during the volatile component release stage.The pyrolysis residual mass increased from the original 27.00％to 40.13％at a torrefaction temperature of 240 ℃.Both the onset and termination decomposition temperatures shifted to higher values with increasing torrefaction temperature.The comprehensive pyrolysis index gradually increased to 2.07 × 10-6％/(min·℃2).Gaussian peak fitting of the main pyrolysis weight-loss stages could better reflect the changes in the proportion of each component in the sample.An increase in torrefaction temperature raised the ignition and burnout temperatures of tobacco waste.The sample torrefied at 210 ℃ had the highest integrated combustion characteristic index of 11.87×10-7％/(min2·℃3).The decomposition kinetics analysis of the main weight-loss stages during pyrolysis and combustion showed that the decomposition process of each sample followed the chemical reaction control model,and torrefaction treatment altered the reaction activation energy during the main weight-loss stages of the samples.Torrefaction pretreatment can be used as a pretreatment method for tobacco waste to enhance its energy density and improve its pyrolysis and combustion characteristics.