Assessment of the Thermal Processing Behavior of Tobacco Waste

Abstract

Pyrolysis of tobacco waste can provide an effective management option, as it produces biogas and bio-oils, which can be subsequently applied for energy recovery, and biochar, which can be used for carbon sequestration when stored in soils. This work assesses the pyrolysis behavior of tobacco waste and reveals four stage pyrolysis mechanism consisting of dehydration (<200 °C), torrefaction (≈300 °C), charring (≈500 °C), and carbonization (≈750 °C). The calorific value of the evolved biogas products at the charring temperature of 500 °C was estimated to be reasonably high and the products can be combusted to generate energy required to self-sustain the pyrolysis process. The bio-oils contained complex chemical structure consisting of nicotine, phenols, and organic acids. The biochar product exhibited enrichment in the fixed carbon, ash, and nutrients P and K, while N remained at relatively constant concentration throughout the pyrolysis process.