Comparison of Thermal Stability Characteristics of Fischer-Tropsch and Hydroprocessed Alternative Jet Fuels in a Fixed Bed Reactor

Abstract

The recent volatility in oil prices has fueled uncertainty about the world’s ability to meet future demands. Furthermore, the growing concern over the negative environmental impacts produced by emissions has resulted in worldwide efforts for developing renewable jet-fuel alternatives. This has led current military and civilian fuel specifications to allow the use of Fischer-Tropsch (FT) and Hydroprocessed fuels (HEFA) in blends up to 50% in volume with regular Jet-A/JP-8. On the other hand, physical properties, and the broad chemical composition, including trace elements in those fuels, may result in engine performance issues found only after extensive operation. This may result in higher maintenance and operation costs. This study presents the coking depositions of several renewable fuels after being stressed in a fixed bed reactor. This was done in an effort to assess the effects (if any) on the thermal stability of renewable fuels interacting with materials representative of state of the art aircraft systems (steel, aluminum, titanium tubing) and to determine whether the use of renewable fuels enhances thermal stability when blended, up to 50%, with oil-derived fuels.

Ellipsometric Measurements of the Thermal Stability of Alternative Fuels

“…However, before an alternative fuel can be used, it must be comprehensively tested for its compatibility with existing infrastructure, engine architecture, combustion, and emission [8][9][10][11], and the infrastructure for its implementation must be built [12]. An important fuel property that must be characterized is the thermal stability [13], which is a measure of the degree to which a fuel breaks down when it is heated. As a weight and space saving measure, the fuel in an aircraft is used as engine coolant in addition to being the propellant.…”

Jet Fuel Thermal Stability Investigations using Ellipsometry

“…Jet fuel thermal stability is a topic of intense research because of its importance in fuel cooled advanced aero engines [1][2][3]. Alternative jet fuels are of interest in the aviation community because of rising oil costs, the need to secure a consistent supply, and the possibilities for cleaner burning engines [4].…”