Production of bio-oils enriched with aroma compounds from tobacco waste fast pyrolysis in a fluidized bed reactor

As tobacco waste production from tobacco industry increases, it becomes important to convert tobacco waste into high value-added products. In this paper, the production of aroma compounds from the fast pyrolysis of tobacco waste was investigated, two kinds of tobacco waste—tobacco leaf fragments (TF), tobacco stems (TS)—and Modeng-brand cigarette tobacco (MT) were used as raw materials in a fluidized bed pyrolysis reactor. Tobacco types, pyrolysis temperatures, and bio-oil separation methods were assigned as influence factors, and the type and content of bio-oil-containing aroma compounds were defined as evaluation standards. Our results indicate that (i) the bio-oil yield under the same pyrolysis temperature (350 °C) is TS > MT > TF; (ii) when TF and MT are used as raw materials, low-temperature (about 350 °C) pyrolysis is beneficial for the production of aroma compounds, whereas TS requires higher temperature (more than 380 °C) pyrolysis; and (iii) bio-oils obtained from different separation methods contain different kinds of aroma compounds, with some compounds requiring certain separation methods. The formation and pyrolysis mechanism of nitrogen (N)-containing compounds in tobacco was also studied. The study demonstrated that nicotine converts to N-containing heterocycles because of secondary decomposition under high temperature.