Thermal conversion of tobacco stem into gaseous products

The pyrolysis of tobacco stem (TS), a potential source of lignocellulosic biomass, is investigated, focusing on gas formation via thermogravimetric analysis–mass spectrometry to obtain accurate gaseous product distributions under various conditions. The results revealed that the majority of the gaseous products were formed under 900 K with a shoulder pyrolysis region (600–800 K) as the main source of gas formation, where the formation curve of CO₂ was used to track the pyrolysis of hemicellulose, cellulose, and lignin. The formation of four aromatics from lignin occurred over the range of 500–900 K, roughly in the sequence of phenol, toluene, xylene, and benzene. Furthermore, the demineralization of TS with HCl did not lead to optimal results, with increased phenol and decreased syngas production, whereas pretreatment with NaOH for hydrolysis was found to significantly increase methane production and decrease the amount of aromatics formed, suggesting that this method should lead to superior results and a simpler reaction mechanism.