Catalytic fast co-pyrolysis of Douglas Fir and low-density polyethylene with nanocellulose-derived carbon catalyst for enhancing selectivity of hydrogen in syngas and mono-aromatic hydrocarbon in bio-oil products

To enhance the quality of raw bio-oil derived from the pyrolysis of biomass, hydrogen-rich reactants such as waste plastics, cooking oils, and soap stock are frequently incorporated into the fast catalytic co-pyrolysis (co-CFP) of biomass. Nevertheless, widespread uses of acids, bases, and zeolite catalysts must address concerns such as easy to coke, regeneration challenges, and environmental impacts. In this study, one green carbon catalyst is derived from nanocellulose (NCCC) and then firstly applied to co-pyrolyze the Douglas Fir (DF), a typical lumber species in North America, together with low-density polyethylene (LDPE), a commonly used plastic. The use of NCCC during feedstock co-pyrolysis boosted the formation of aromatics, particularly the mono-aromatic hydrocarbons (MAHs) in bio-oil and H2-rich gaseous products, with a selectivity of H2 to 65 vol.%, nearly double the selectivity without catalysts. Even after five consecutive applications, the NCCC still displays good catalytic effectiveness in the co-pyrolysis: its selectivity for H2 in gaseous products (48 area%) after five-time usage is virtually equal to that without catalysts (46 area%). Moreover, the mechanism of the NCCC application was investigated by applying the NCCC in a co-pyrolysis of LDPE and DF, along with their individual pyrolysis at temperatures ranging from 450 to 800 °C. This research investigated the potential catalytic impacts of NCCC in co-CFP process, aiming to provide an affordable, eco-friendly heterogeneous catalyst to replace existing acid/base catalysts in the conversion of biomass.