Assessment of HEFA, ATJ, GTL-S8 and Farnesane as alternative jet fuels based on their water shedding characteristics

Previous studies have shown that impurities like surfactants in jet fuel have impacted the performance of coalescer filters. Therefore, aircraft maintenance schedules require an additional operation which is commonly known as water sumping. Normally after bulk fuel transfers, fuels are allowed to settle in tanks and sumping is carried out to remove free water. Water settling tests can indirectly measure surfactants in jet fuels, yet there is no reliable data that focuses on the water settling rate of alternative jet fuels that comply with or are very similar to the Jet A-1 specification. Additionally, the influence of the jet fuel composition on the rate of water-shedding is still unknown. Therefore, there is a need for a reliable study to fill this lack of knowledge. In this work, the water settling rate of five different jet fuels made to different national standards in comparison to conventional Jet A-1 fuel was evaluated. GTL S-8, HEFA and ATJ has been identified as potential/alternative candidates for ASTM D7566 certified jet fuels.

既往研究表明，喷气燃料中诸如表面活性剂（surfactant）一类的杂质会影响聚结过滤器（coalescer filter）的性能。因此，航空器维护规程要求增设一项俗称“放水作业（water sumping）”的操作工序。通常在批量燃油转运完成后，燃油会在储油罐中静置沉降，随后通过放水作业去除游离态水分。油水沉降测试可间接检测喷气燃料中的表面活性剂含量，但目前尚无针对符合或高度接近Jet A-1规格的替代喷气燃料的油水沉降速率的可靠研究数据。此外，喷气燃料的组分对其脱除水分速率的影响仍未明确。因此，亟需开展可靠的相关研究以填补这一认知空白。本研究针对五种符合不同国家标准的喷气燃料，以传统Jet A-1燃油作为对照，对其油水沉降速率展开了评估。GTL S-8、HEFA与ATJ已被认定为符合ASTM D7566认证标准的潜在替代喷气燃料候选品类。