Aromatic bio-oil production from corn stover by FAU + MFI dual-catalyst catalytic fast pyrolysis: A study of two catalyst parameters

The dual-catalyst catalytic fast pyrolysis (CFP) is a promising approach for producing hydrocarbon-rich bio-oil from biomass waste. However, the lack of detailed research on the structural parameters of the first- and second-layered catalysts was lacking and hindered the development of this technology. Herein, dual-catalyst CFP of corn stover was conducted, and the effects of the acidity and porosity of the two-layered catalysts were studied in detail to enhance their synergistic effect. The results demonstrated that for the second-layered catalyst (MFI zeolite), the utilization of a strong acidic ZSM-5(25) facilitated the production of aromatic hydrocarbon (38.8 area%). For the first-layered catalyst (FAU zeolite), the employment of medium acidity and microporous HY(2.6) was advantageous for the production of valuable monocyclic aromatic hydrocarbon (MAHs) with a selectivity of 21.5 area%, which was ∼1.6 times higher than that in the less acidic HX(1.5) + ZSM-5(25) trial. These findings confirmed that the synergy between the two-layered catalysts was dramatically enhanced by using the HY(2.6) + ZSM-5(25) catalyst combination. Finally, a proposed reaction pathway for the dual-catalyst CFP of corn stover was provided to guide the optimization of dual-catalyst CFP technology and the design of pyrolysis catalyst.