PHENOLS AND AROMATIC METHYL ETHERS FROM BIOMASS PYROLYSIS OIL: IMPLICATIONS FOR JET FUEL STABILITY

摘要

Jet fuel is used as a heat sink for aircraft systems and is thus required to be thermally stable. Jet fuel instability could cause deposits, which may foul aircraft components. Renewable jet fuel can be produced from biomass pyrolysis oil, although concerns may exist about its high phenolic content, since some phenols have a high propensity to form deposits. In this paper, the removal of detrimental phenolic species in jet fuel by conversion to aromatic methyl ethers was evaluated as a novel method of improving the thermal stability of jet fuels derived from biomass. The thermal and oxidative stability of a model fuel and a jet fuel derived from biomass pyrolysis oil, containing a variety of phenols and/or aromatic methyl ethers, was studied using a Quartz Crystal Microbalance (QCM) technique and the Jet Fuel Thermal Oxidation Test (JFTOT) method. The jet fuels containing phenols indicated strong depositing propensities, whereas the jet fuels containing the corresponding aromatic methyl ethers showed reduced depositing propensity. Small amounts of phenols present in the kerosene derived from biomass pyrolysis oil were converted to the corresponding methyl ether using an organic synthesis technique and this was shown to improve the thermal stability of the fuel significantly. This study demonstrated that aromatic methyl ethers are of a high relative thermal stability when compared to their phenolic counterparts. The reduced amount of deposits formed in fuels containing aromatic methyl ethers may be attributed to the strong ether bond linkage (O-CH3) that is stable under the thermal oxidative stressing conditions experienced by jet fuel.