Abstract

Catalytic fast pyrolysis of lignocellulosic biomass is a promising thermochemical route for producing renewable biofuels and value-added chemicals. Many African countries have abundant underutilized agricultural residues whose reuse can improve waste management while reducing reliance on fossil fuels. This study used wheat straw as a representative residue to examine how two catalysts—zinc oxide (ZnO) and cement kiln dust (CKD)—affect bio-oil yield and quality. Bench-scale experiments were performed in a fixed-bed reactor under an inert nitrogen atmosphere at 500–600 °C. Each catalyst was tested separately at loadings from 0 to 7 g per 500 g of biomass to evaluate impacts on product distribution and composition. Bio-oil, biochar, and non-condensable gas yields were measured, and Gas Chromatography-Mass Spectrometry was used to characterize bio-oil chemical profiles. Without catalysts, bio-oil yield increased from 21.8 wt.% at 500 °C to 28.2 wt.% at 600 °C. With catalysts, the highest oil yield occurred at 500 °C using 5 g ZnO (30.6 wt.%), while CKD gave 26.8 wt.% under the same condition. At 600 °C, ZnO's oil yield decreased to 25 wt.%, whereas CKD remained near 28.6 wt.%, so catalytic yield advantages largely disappeared at the higher temperature. Quality varied: ZnO produced lighter, less heavy-fraction oils at both temperatures, while CKD at 600 °C generated a bimodal oil dominated by a heavy halogenated aromatic, indicating post-polishing is needed; overall, ZnO (5 g) at 500 °C maximized yield, ZnO at 600 °C improved volatility, and CKD was more yield-stable at 600 °C but with quality drawbacks.

Department(s)

Chemical and Biochemical Engineering

Publication Status

Full Text Access

Keywords and Phrases

Bio-oil; Biochar; Cement kiln dust; Comparative catalytic pyrolysis; Wheat straw; Zinc oxide

International Standard Serial Number (ISSN)

1873-2909; 0961-9534

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Elsevier, All rights reserved.

Publication Date

01 Jul 2026

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