Fuel-range liquid hydrocarbon products from catalytic deoxygenation of mixtures of fatty acids obtained from the hydrolysis of rapeseed oil

Morenike A. Peters, Jude A. Onwudili*, Jiawei Wang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The combined hydrolysis–deoxygenation method reported here demonstrates the efficiency of hydrogen-free catalytic conversion of lipid-derived multi-fatty acids into renewable drop-in hydrocarbon biofuels. Using a 5 wt% Pt on carbon (5 wt% Pt/C) catalyst for a detailed deoxygenation study, experiments were conducted in a batch reactor under nitrogen atmosphere at various temperatures (350–400 °C), reaction times (0–3 h) and catalyst/feedstock mass ratios (0–0.2). The Pt/C catalyst showed remarkable selectivity towards the decarboxylation mechanism, as evidenced by substantial CO2 formation. The Pt/C-catalysis optimal conditions were: 400 °C, 2 h reaction time and a catalyst/feedstock mass ratio of 0.2, resulting in a yield of 3.76 wt% gasoline, 14.7 wt% kerosene and 53.7 wt% diesel range hydrocarbons. Under the set of optimal conditions, five other catalysts with different supports were tested and the results showed that 5 wt% Pt/MgSiO3 and 5 wt% Pt/Al2O3 catalysts enabled complete conversion of fatty acids (total acid number = 0 mg KOH g−1). In contrast, 5 wt% Pt/SiO2, 5 wt% Pd/MgSiO3 and bimetallic 10 wt% Ni–Cu/Al2O3 performed poorly, indicating the effects of both the active metal and metal–support interaction on the conversion of fatty acids. In all cases, the oil products were dominated by heptadecane, originating from decarboxylation and in situ hydrogenation of the dominant oleic acid (74.4 wt%) and other C18 fatty acids present in the hydrolysed feedstock. Visually, only the Pt/C catalyst produced light-coloured liquids with direct-use fuel appeal, possibly due to its mildly acidic nature and comparably much larger surface area of 650 m2 g−1.
Original languageEnglish
Pages (from-to)4820-4837
Number of pages18
JournalSustainable Energy & Fuels
Volume8
Issue number20
Early online date13 Sept 2024
DOIs
Publication statusPublished - 21 Oct 2024

Bibliographical note

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (https://creativecommons.org/licenses/by/3.0/).

Data Access Statement

All relevant data generated from this study have been included in the main article and Electronic Supplementary Information (ESI) at the article link. Additional data will be provided on request.

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