A study by a team of researchers from the US, Germany and Canada has found that sustainable aviation jet fuels show up to a 70% reduction in particle mass emission compared to a fossil fuel. The study, which summarizes the results from a ground-based measurement activity conducted in January 2018 as part of the ECLIF2/ND-MAX campaign in Ramstein, Germany, is published in the journal Fuel.
The team burned two fossil reference kerosenes and three different blends with the renewable fuel component HEFA-SPK (Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene) in an A320 with V2527-A5 engines to investigate the effect of fuel naphthalene/aromatic content and the corresponding fuel hydrogen content on non-volatile particle number and mass emissions.
Reductions up to 70% in non-volatile particle mass emission compared to the fossil reference fuel were observed at low power settings. The reduction tends to decrease with increasing power settings.
The fuels showed a decrease in particle emission with increasing fuel hydrogen content. A second fossil fuel with similar hydrogen content as one of the HEFA blends featured similar reduction factors in particle mass and number.
Changes in the fuel naphthalene content had significant impact on the particle number emission.
A comparison to in-flight emission data showed similar trends at cruise altitudes.
The measurements highlight the importance of individual fuel components in regulating engine emissions, particularly at the low thrust settings typically employed during ground operations (e.g. during idle and taxi). Therefore, when selecting and mixing SAF blends to meet present fuel-certification standards, attention should be paid to minimizing complex aromatic content to achieve the greatest possible air quality and climate benefits.
—Schripp et al.