Catalytic Routes to Liquid Aviation Fuels from Lignocellulosic Feedstocks

  • Joseph Donnelly

Student thesis: Doctoral ThesisPhD


Global warming is perhaps the most urgent and critical problem that we face today. A large proportion of anthropogenic global warming is understood to occur due to the combustion of fossil fuels for the purpose of transportation. The contribution of aviation to global warming has, in recent years become increasingly recognised. Due to the significant increase in passenger air travel predicted in the future we must seek to lessen the impact of aircraft emissions through the development of suitable alternative liquid fuels that may be used within current infrastructure.Whilst alternative fuels have been developed such biodiesel from triglycerides and bio-ethanol, these utilise food competitive feedstocks, and also exhibit some undesirable physical properties meaning that whilst they may be used in road transport infrastructure, they remain unsuitable for use in aviation. The production of sustainable alternative fuels that possess suitable physical properties for use in aviation, necessitates design of biomass conversion technologies in order that they may yield products which satisfy the stringent criteria set out in aviation turbine fuel standards.In chapter 2 a biocatalytic route to C10-12 alkane precursors was investigated. A benzaldehyde lyase catalysed conversion of the biomass derived furanic compounds, furfural and 5-hydroxymethylfurfural (5-HMF), was found to carboligate these molecules at room temperature and ambient conditions. The product mixture was found to be tailorable between 10 and 12 carbon chain length precursors.In chapter 3, the suitability of a low temperature thermochemical conversion technology was explored. A previously reported Pd/C catalysed alkylation was used for alkylation of a theoretical permutation of a product mixture available from Acetone Butanol Ethanol (ABE) fermentation. Whilst straight chain products available through the use of ABE, the substitution of the alcohol constituents for isoamyl alcohol and isobutanol was found to enable production of branched chain aviation fuel precursors, with much improved low temperature properties relative to their straight chain analogues.In chapter 4 is presented an investigation into a liquid phase pyrolysis technology, with analysis of its efficacy with regard to conversion of a food industry waste to biofuel using zeolite catalysts. Conversion efficiencies were found to be up to 7 %iiiusing the bench scale system in this investigation, however oxygen content of the fuels produced were found to be exceptionally low for a biomass derived feedstock, and as such the process warrants further investigation.The fuels from chapter 2 and 3 were taken forward for engine testing. Blends of these potential alternative fuels were made up with Jet A-1, and used to power a AMT, mercury HP micro gas turbine. The test cycle used ranged across 4 throttle settings from 0, 30, 60 and 90 %. It was found that whilst emissions for alternative fuel blends remained largely unchanged for most emissions, a difference in thrust was measured, with hydrocarbon fuels providing higher thrust at lower throttle settings and at 60 % and 90 % throttle, oxygenate fuels providing more thrust.
Date of Award27 Jun 2017
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorChris Chuck (Supervisor), Christopher Bannister (Supervisor) & Marcelle McManus (Supervisor)

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