Spatially resolved chemical releases during thermal distillation and pyrolysis of packed tobacco biomass

With increasing popularity of Heated Tobacco (Nicotiana tabacum L.) Products (HTPs), a substantial volume of tobacco waste is generated after their use. The subject of this biowaste on potential human and environmental impacts has not attracted research. The characterization of the residual bio-contents during and after tobacco pyrolysis can offer insights into rational utilization of tobacco waste and for environmental protection. In this study, we conducted a spatial characterization of the residual contents of heated tobacco during thermal distillation and pyrolysis, accompanied by the evaluation of volatile and aerosol generation. Firstly, the temperature distribution and the degree of thermal transformation of the internal tobacco matrix around the heater were measured. Secondly, by dividing the heated tobacco rod into nine segments, thermogravimetric and chemical analysis were performed on the representative tobacco segmentation to investigate the main compounds released during pyrolysis. Finally, thermal release behaviors of major aerosol and volatile compounds of the tobacco matrix were investigated. The extents of the weight loss of the tobacco segments were correlated to the temperature inside the tobacco rod. The results showed a correlation between 1,2-propylene glycol (PG), nicotine, and glycerol (VG) in the various segments, and their relationship to the heating temperature and their boiling points of the substance. Furthermore, the release behavior of evolved gaseous compounds across different temperature ranges corroborated with the aforementioned thermophysics. Our findings provide valuable insights into the thermochemical properties of tobacco during thermal distillation and pyrolysis, and their possible bio-utilization post heating.