Jet fuel properties

G. M. Varga and A. J. AveW, Jet Fuel Property Changes and Their Effect on Producibility and Cost in U.S., Canada, and Europe,F ASA Contract Report 174840, Lewis Research Center, Qeveland, Ohio, Feb. 1985. 

F product meets almost all jet fuel properties, as shown in Table II. The Wyodak syncrude is easier to hydroprocess and produces specification jet fuel at 1.0 LHSV and the above conditions. The only property which was not met consistently was the API gravity. If need be, the gravity specification could be met for the jet- product from all of these syncrudes by adjusting the end point of the jet fuel. Specification jet fuel was made on this catalyst after 4000 hours of operation. 

Jenkins, G.I., Walsh, R.E. 1968. Quick measure of jet fuel properties. Hydrocarbon Process. 47(5) 161-164. 

The properties linked to storage and distribution do not directly affect the performance of engines and burners, but they are important in avoiding upstream incidents that could sometimes be very serious. We will examine in turn the problems specific to gasoline, diesel fuel, jet fuel and heavy fuel. 

Petroleum and Petrochemical Processes. The first large-scale appHcation of extraction was the removal of aromatics from kerosene [8008-20-6J to improve its burning properties. Jet fuel kerosene and lubricating oil, which requite alow aromatics content (see Aviation and OTHER gas... 

Because the jet engine was free of the demanding need for high-octane fuel, in the early days of the jet-engine development it was thought that it could use practically any liquid fuel. However, subsequent experience proved this to be untrue, as a number of potential problem areas indicated that control of fuel properties, reflecting both bulk and trace components, were important for satisfactory use. Over the years these important property requirements were translated into specification requirements that put restrictions on what is acceptable as jet fuel. 

The presence of small amounts of dissolved polymer can alter sizably the aerosol particle dimensions when the solutions are sprayed. This antimisting property has received special attention in an effort to develop additives for jet fuel to prevent accidental ignition following crash landing. As in drag reduction, the polymer... 

The high-surface-area TUD-1 can serve as an anchor for many catalysts. Si- or Al-Si-TUD-1 (24,25) can be used as a support for various noble metals (Pt, PtPd, Ir, etc.). This will provide catalysts suitable for the hydrogenation of olefins and aromatics. In the refining industry, one use is the hydrogenation of polynuclear aromatics ( PNAs ) in diesel fuel, which can lower the fuel s toxic properties. Also, jet fuel has an aromatics constraint, designed to lessen smoke formation. Cracked stocks (e.g., coker or visbreaker liquids) generally have undesirable olefins (especially a-olefins) that also need to be saturated prior to final processing. 

Jet fuel is classified as aviation turbine fuel, and in the specifications, ratings relative to octane number are replaced with properties concerned with the ability of the fuel to bum cleanly. Jet fuel is a light petroleum distillate that is available in several forms suitable for use in various types of jet engines. The exact composition of jet fuel is established by the U.S. Air Force using specifications that yield maximum performance from the aircraft. The major jet fuels used by the military are JP-4, JP-5, JP-6, JP-7, and JP-8. 

Has properties similar to those of diesel and higher-boiling jet fuels. 

The term white distillate is applied to all the refinery streams with a distillation range between approximately 80 and 360°C (175 to 680°F) at atmospheric pressure and with properties similar to the corresponding straight-run distillate from atmospheric crude distillation. Light distillate products (i.e., naphtha, kerosene, jet fuel, diesel fuel, and heating oil) are all manufactured by appropriate blending of white distillate streams. 

Jet fuel fuel meeting the required properties for use in jet engines and aircraft turbine engines. 

No. 2 fuel oil has properties similar to those of diesel fuel and heavy jet fuel used in burners where complete vaporization is not... 

Oxygen-containing impurities such as phenols and naphthenic acids can adversely affect water separation properties and initiate gum formation. No limit presently exists to control the amount of oxidized organic compounds found in jet fuel. However, tests for existent gums, neutralization number, and water separation indirectly limit the presence of oxygenated materials in jet fuel. 

Corrosion Inhibitor - helps prevent rusting of metal engine components. Also, corrosion inhibitors provide a protective film on metal surfaces to aid in improving the lubricating properties of jet fuel. Use is not permitted in aviation gasoline and civil jet fuels, but is mandatory in military jet fuel grades. 

Tetraethyl Lead - used to improve the octane number (antiknock) properties of gasoline. Use is mandatory in aviation gasoline. Tetraethyl lead is not permitted in civil and military jet fuel. 

Fuel system corrosion inhibitors must have a low tendency toward emulsification with water and toward foam enhancement in turbulent systems. These properties are especially critical whenever inhibitors are used in jet fuel. The sensitivity of jet fuel pumping and injection systems requires that fuel be free of emulsions and foam. 

Jet Fuels (Grades JP-3, JP-4, JP-S JP-6). Specifications for early aircraft jet fuels were based primarily on manufg considerations, since it was believed that aircraft could burn almost anything of the nature of kerosene fuels (Ref 1). Later improvements in aircraft, particularly in high-speed jets, made it necessary to pay more attention to fuel characteristics and less attn to ease of manuf. The most important of these fuel characteristics is fuel stability at high temps. Other problems associated with jet aviation fuels, both for military civilian use, are minor compared to stability at high temps. Such problems include availability, handling physical property specifications... 

Another possible solution to the problem of high temperature stability is the use of additives. Not exactly a stranger to petroleum people (as evidenced by use in gasoline and lubricants) they generally fall into two classes metallic and non-metallic. The former, for the most part are metal salts of sulfonates or naphthenates, whereas the latter are either amines or amine derivatives (later other organics may prove more effective) Use of additives in jet fuels, however, must of necessity be approached with caution. As surface active materials, many have a variety of uses and properties. Hence, they must not introduce new problems such as foaming at high altitudes, emulsification, or interference with low temperature flow. These could easily be severe limitations, but additives are under serious consideration thruout the industry... 

Feeds. Properties of two hydrofined test feeds are given in Table I. The California gas oil blend was used in tests simulating a hydrocracking unit producing both naphthas and jet fuel, the Mid-Continent blend in tests representing a unit producing naphtha as the major product. 

A recent study by Franck et al. at the Institut Francais du Petrole (11) indicates that naphthenic hydrocarbons with two or three rings (molecular weight between 120 and 200) give the best compromise among the different properties of jet fuels. 

Yield periods for these three syncrudes, refined to specification jet fuel, are shown in Table III. Accurate yields of the very small 600° F- " portion were not determined for these periods. The yields in Table III show this cut combined with the jet cut. The yield of the 600° F- " cut is approximately 5 vol % for the Illinois H-coal syncrude and 2.5 vol % for the Wyodak H-Coal and SRC-II syncrudes. Properties of the jet fuels are shown in Table IV. 

Properties of the naphthas produced from the syncrudes in the above tests are shown in Table V. Dinaphthenes are found in the 300-350°F naphtha and, surprisingly, in the 250-300°F naphtha. High levels of these compounds can make coal-derived naphthas difficult to reform. ( 9) A combination gas chromato-graphic-mass spectrometric (GC-MS) analysis of the 250-300°F naphtha from hydrotreated Illinois H-Coal found that the dinaphthenes are 8-carbon atom compounds (1.8% octahydropenta-lene) and 9-carbon atom compounds (0.7% bicyclo 3.3.1 nonane, 0.4% methyloctahydropentalene, 1.0% octahydroindenes, and 2.6% unidentified compounds) These dinaphthenes should not yield naphthalene when reformed. If the initial point of the jet fuel is 300°F or less, the 300°F " naphtha should be easy to reform. 

The yield periods for the preparation of diesel fuel are shown in Table III. These yield periods are the same as shown above in the jet fuel case. Properties of diesel fuel cuts and naphthas are shown in Tables IV and V, respectively. 

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