UNDERSTANDING PHENOL LEVELS IN JET FUEL

摘要

Phenol compounds naturally occur in crude oil. As a result, jet fuel has always contained small amounts of phenols. Phenols can impact thermal stability, materials compatibility and additive response. Phenol levels in jet fuel are not routinely measured therefore a database of historic baseline levels is unavailable. Scattered literature reports using different analytical methods reveal phenol levels in jet fuel may range up to 1995 mg/L with an average of 286 mg/L. The potential for phenol levels to trend upward due to water recycling within the refinery has prompted us to undertake an effort to better understand phenol levels in jet fuel. Whether or not phenol levels are trending can be understood only after an appropriate test method is selected or devised and a baseline survey completed. An analytical test method, based on aqueous base extraction of phenols from jet fuel followed by HPLC with UV detection of the aqueous extract, was developed to quantify phenol levels in jet fuel in five size categories down to low ppm levels. A variety of jet fuel samples collected by the Colonial Pipeline (CPL) in the summer of 2012, were used to initiate a baseline survey. The phenol levels ranged from 1 - 373 mg/L (average 131 mg/L). Negligible amounts of Co were found, 5% of the jet fuel samples reflect C2 as the major phenol type, 80% reflect C4+ as the major phenol type, and the remaining 15% reflect a unvarying molecular structure distribution from C2 to C_(4+). A follow-up survey using a smaller sample set in 2013 revealed a similar range, slightly lower average level of phenol in jet fuel and C_(4+) as the major phenol type. The purpose of this work is to highlight the analytical method for quantifying phenols, understand baseline levels of phenols in jet fuel and determine if they are trending. Investigation into the impact of various phenols on jet fuel thermal stability is also discussed.