Production of low-oxygen oil via catalytic co-pyrolysis of biogas residue and plastics by ZSM-5

This work aimed to produce low-oxygen bio-oil through the co-pyrolysis of biogas residue (BR) with polyethylene (PE) and polypropylene (PP). The effects of co-pyrolysis interactions on the kinetics and oxygen product distributions were studied. The kinetic results showed that the interaction of BR with PE in BR/PE blends decreased the apparent activation energy (E) in a range of 9.9-33.4 kJ/mol. The presence of PE promoted the deoxidation of oxygenated compounds as the proportion of PE in the mixture increased, which was attributed to free radicals produced by PE that reacted with the oxygenated compounds produced by BR. The presence of PP reduced the oxygen content and alcohols formed in the oil, possibly because of the incomplete conversion of ketones. The content of oxygenated compounds in the oil decreased from 69.5 wt.% to 2.5 wt.% and then 0.4 wt.% in the presence of PE and PP. Additionally, the Zeolite Socony Mobil-5 (ZSM-5) catalyst promoted the formation of alkanes and aromatics, ensuring a high content of CnHm in the oil, and led to 1.3 and 2.4 wt.% oxygenated compounds in BR/PE and BR/PP blends, respectively, demonstrating the possibility of using pyrolysis oil as biodiesel.