New research on complex reactions paves the way for more efficient, more sustainable aviation fuel

Jet engine closeup

Researchers from the University of Sheffield's Energy Institute and Energy 2050 research group have published new exploratory insights into the behaviour of metals in jet fuels, aiming to understand why they increase the rate of deposition - a process which can damage jet engines.

The research, across two papers authored primarily by Dr Ehsan Alborzi and Dr Christopher Parks, will ultimately lead to improvements in the sustainability of aviation fuel and thus be less damaging to jet engines in the long-term.

The two papers, both published in Energy and Fuels, give insight into how and why certain metals increase the rate of autoxidation. This process causes an increase in deposit formation which in turn can obstruct filters or fuel nozzles and results in the need to replace the blocked components with greater frequency. Research into the reasons why this reaction happens will aid the development of more efficient fuels and lead to more sustainable aviation as a whole.

The underlying interactions of fuel chemicals, dissolved metals and hydroperoxides are not clearly understood - although we know that the interference happens, there is no clear consensus on the precise nature of the interactions. To try and uncover the mysteries of the science, the group have used their research to begin identifying the exact nature of the reactions on a molecular level using quantum modelling and by testing different chemicals to compare results.

Their laboratory experiments involved removing sulfur from the type of fuel known as Jet A-1 by treating it with activated carbon. It was found that the removal of sulphur and metals is able to significantly reduce the amount of observed deposition in Jet A-1 fuel.

In a continuation of this research, Dr Christopher Parks's paper considers why metals affect fuels in the way they do. There is very limited research into the reasons behind the reaction, and though currently only theoretical, Dr Parks's paper is one of the first to pose a more detailed theory, using computational modelling to explain the complex chemical reactions.

It's hoped that their findings can be used to develop a more robust chemical model which can predict in the rate of deposition in different types of fuel, ultimately finding the best fuel composition to use in different types of aviation engine. This most recent research marks significant progress in developing an accurate, detailed concept for future use.

Speaking about the research, Dr Parks said, "Making aviation engines more efficient in the long run - with less servicing required and a reduction in frequency engines require new parts - is one of the many ways we can make flying more sustainable. Our research is just one step on a long path towards this goal, but as technology improves and we discover more about these little-understood chemical reactions, we hope to be able to find solid evidence which moves us closer towards better aviation fuel and engineering".

Read the full papers from the journal of Energy and Fuels:

Effect of reactive sulfur removal by activated carbon on aviation fuel thermal stability

Density functional theory calculations on copper-mediated peroxide decomposition reactions: Implications for jet fuel autoxidation

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