Abstract
This thesis embarks on an in-depth exploration of sustainable aviation fuel (SAF) production, emphasizing the innovative combination of natural rubber and palm oil as feedstocks. It begins with a comprehensive literature review that introduces the background of SAF, including its development drivers and associated policy frameworks. Special attention is given to existing hydroprocessing technologies, particularly those tailored for lipid conversion into jet fuel range hydrocarbons without using added molecular hydrogen. An integrative approach is discussed, evaluating the combined conversion of natural rubber and palm oil. In this process, natural rubber is broken down into limonene. This limonene is then dehydrogenated to form cymene, a key component in SAF, while simultaneously producing hydrogen. This hydrogen, derived from the limonene, plays a crucial role in the subsequent step of deoxygenating palm oil, effectively removing oxygenated compounds and contributing to the production of SAF.The experimental section centres on the synergistic combination of limonene (representing natural rubber) and palmitic acid (symbolizing palm oil). The study evaluates the performance of various catalyst systems, especially those involving copper (Cu) and nickel (Ni). The catalysts' efficacy in leveraging limonene for palm oil deoxygenation is examined through a wide range of characterization techniques. Further exploration delves into all-in-one-pot reactions: catalyst synthesis, catalyst sulphidation, natural rubber depolymerization and lipid deoxygenation. In addition, a comparative analysis is conducted between transition metal sulphides, MoS2 and WS2, focusing on their catalytical performance in hydrodeoxygenation, decarbonylation, and decarboxylation processes. Additionally, the thesis investigates the use of used cooking oil as a sustainable alternative feedstock.
The study progresses to apply the optimal catalyst system in a fixed-bed reactor with continuous flow, transforming the catalyst powder into shaped extrudates for a fixed-bed tubular reactor. The energy requirements for rubber depolymerization and a preliminary techno-economic analysis are also presented to evaluate the feasibility of this conversion process for SAF production. By generating extensive experimental data and drawing on insights from
existing literature, this research draws significant conclusions and offers valuable suggestions for future studies in the field of SAF production using natural rubber and palm oil.
Thesis is embargoed until 31 July 2029.
| Date of Award | Jul 2024 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Sponsors | Petronas Research |
| Supervisor | John Holbrey (Supervisor) & David Rooney (Supervisor) |