Catalytic co-pyrolysis of solid wastes (low-density polyethylene and lignocellulosic biomass) over microwave assisted biochar for bio-oil upgrading and hydrogen production

Metal catalysts are unavoidable within the process of catalytic pyrolysis, a part of hydrogen production; as a result, the reuse and disposal of these materials are problems that need to be solved. Biochar, with its extensive sources, large specific area, and developed pores, has the potential to be developed in this catalytic area. In this study, we used microwave-assisted corn stover biochar as a catalyst in the co-pyrolysis of Douglas Fir (DF) and low-density polyethylene (LDPE) in order to investigate its catalytic effects. The results showed that the biochar significantly increased the selectivity of hydrogen (H₂) in the syngas, and the highest selectivity that could be achieved was 72 vol% at 650 °C, with a biochar (BC)/feedstock ratio of 4. Furthermore, the application of biochar decreased the wax yield and contributed to the good selectivity of aromatics. The biochar developed in this study was also proven to show good reusability, as even after 10 times of reuses, the biochar still achieved a yield of H₂ over 50 vol%.