Branched Ketone Biofuels as Blending Agents for Jet-A1 Aviation Kerosene

Abstract

In this investigation a range of ketone biofuels produced from the alkylation of isoamyl alcohol and isobutanol were examined as potential blending agents with Jet A-1 aviation kerosene. The fuels were synthesised under solvent-free conditions using a Pd/C catalyst with K3PO4, previously reported for the alkylation of acetone, butanol, ethanol (ABE) fermentation mixtures. Reasonable yields and selectivity were achieved for branched alkylation products with up to 61 % produced from isoamyl alcohol and 64 % from isobutanol. The key aviation fuel properties of the mixtures were tested unblended and in 50% and 20% blends with Jet A-1 aviation kerosene. The freezing point of the fuels were all found to be below the required-47 °C irrespective of blend or the temperature of the reaction. The energy density of the unblended fuels ranged between 30.4-41.36 MJ/kg depending on the temperature of the reaction and whether remaining alcohols were removed. While this is below the HHV of the Jet A-1 used (45.69 MJ/kg) the energy density of the 50% and 20% blends were more suitable with the isoamyl alcohol derived fuels having a maximum HHV of 44.31 MJ/kg at 50% blending and 44.99 MJ/kg at 20% blend with Jet A-1. The fuels derived from isoamyl alcohol produced above 140 °C were found to satisfy the flash point criterion (>38 °C) of the Jet A-1 specification, though the isobutanol derived fuels did not, producing fuels with flash points between 33 °C and 35 °C. The kinematic viscosity of the fuels were also tested at-20 °C. Unblended only a few of the fuels analysed met the maximum viscosity requirement at-20 °C of 8 mm 2 s-1 , though this fuel property was improved substantially on blending with jet fuel. This work demonstrates that ketones produced from isoamyl alcohol through a simple alkylation have the potential to be used as blending agents with Jet A-1.

The Effect of Functional Groups in Bio‐Derived Fuel Candidates

“…It was reported that branched ketones can have a positive effect on fuel properties. In a study by Donnelly, et al., the production and fuel analysis of C 8 –C 15 branched ketones through the alkylation of branched alcohols (isoamyl alcohol or isobutanol) and acetone with Pd/C and K 3 PO 4 was carried out . When in a 20 % blend with Jet A‐1, all fuel molecules produced suppressed the melting point below that of pure Jet A‐1, all were found to be below the maximum viscosity of 8 mm 2 s −1 , and all were above the minimum Jet A‐1 energy density of 42.8 MJ kg −1 .…”

Systems-Level Analysis of Energy and Greenhouse Gas Emissions for Coproducing Biobased Fuels and Chemicals: Implications for Sustainability

“…A model compound approach is utilized to represent complex real-world mixtures of bio-oil constituents in terms of their most prominent molecular components and is consistent with methods of prior studies. − As per the experimental yield data (Table S1), seven groupings of torrefaction bio-oil product compounds are considered here as model compounds: carboxylic acids as acetic acid, light oxygenates as acetol, furanics as furan and furfural, aromatics as toluene, multifunctional phenolics as guaiacol, alkylated phenolics as m -cresol, and anhydrous sugars as levoglucosan. These model compounds are then converted to C6+ transportation fuels and specialty chemicals via a host of upgrading chemistries, including ketonization, alkylation, hydrolysis and oxidation, hydrogenation, and hydrodeoxygenation (HDO) .…”

Biofuels in Aviation: Exploring the Impact of Sustainable Aviation Fuels in Aircraft Engines

“…Studies have demonstrated that blends of biofuels and conventional jet fuels can reduce emissions of greenhouse gases and particulate matter, contributing to cleaner combustion and reduced environmental impact. However, the stability, cold flow properties, and combustion characteristics of these blends are critical parameters that need continuous monitoring and optimization to meet the operational requirements of commercial aviation [71,72].…”