PRE-REFINED CRUDES AND THEIR IMPACT ON JET FUEL THERMAL STABILITY OVER TIME

摘要

Historically, jet fuel simply consisted of the straight run kerosene cut from crude oils. This endured for years while market demand remained below the average kerosene yield from a barrel of oil. While jet fuel demand increased over time, the kerosene portion of the crude barrel decreased due to a general drop in crude quality. Gradual introduction of pre-refined crudes (PRCs) into refinery crude slates provides an example of declining crude quality. With regard to PRC's impact on jet fuel quality, the most notable change was the inability of some fuels to maintain their thermal stability properties during storage. This fit for purpose (FFP) property has been characterized by the fuel's JFTOT Breakpoint Degradation (JBD). Normal refinery processing of jet fuels derived from a PRC may produce a fuel that meets all of jet fuel specification Table 1 requirements (e.g. D1655, Def. Stan. 91-91 etc.); however, some may not remain FFP. The potential exists for the fuel to degrade over time and fail JFTOT while being stored in the field. Refineries need to be aware of this FFP property and ensure adequate treating is applied to jet fuels derived from PRCs. JBD has been identified as a key FFP property for jet fuels derived from PRCs. A JBD protocol and FFP definition is presented, providing guidance as to how to ensure on specification PRC derived jet fuels while taking post production storage requirements into consideration.