Turbine fuel production

Urea has the remarkable property of forming crystalline complexes or adducts with straight-chain organic compounds. These crystalline complexes consist of a hoUow channel, formed by the crystallized urea molecules, in which the hydrocarbon is completely occluded. Such compounds are known as clathrates. The type of hydrocarbon occluded, on the basis of its chain length, is determined by the temperature at which the clathrate is formed. This property of urea clathrates is widely used in the petroleum-refining industry for the production of jet aviation fuels (see Aviation and other gas-TURBINE fuels) and for dewaxing of lubricant oils (see also Petroleum, refinery processes). The clathrates are broken down by simply dissolving urea in water or in alcohol. 

The exacting Hst of specification requirements for aviation gas turbine fuels and the constraints imposed by deUvering clean fuel safely from refinery to aircraft are the factors that affect the economics. Compared with other distillates such as diesel and burner fuels, kerosene jet fuels are narrow-cut specialized products, and usually command a premium price over other distillates. The prices charged for jet fuels tend to escalate with the basic price of cmde, a factor which seriously underrnined airline profits during the Persian Gulf war as cmde prices increased sharply. 

Aircraft Fuels. Demand for aviation gas turbine fuels has been growing more rapidly than demand for other petroleum products since 1960, about 3—5% per year compared with 1% for all oil products. This strong demand reflects a current and predicted growth in worldwide air traffic of 4—7% annually until the end of the century. Total world oil demand will be up by 15% by the year 2000, but aviation fuel demand will increase by 50—125%. However, the fraction of the oil barrel devoted to aviation, now about 8%, will increase only slightly. 

Synthetic fuels derived from shale or coal will have to supplement domestic suppHes from petroleum someday, and aircraft gas turbine fuels producible from these sources have been assessed. Shale-derived fuels can meet current specifications if steps are taken to reduce the nitrogen levels. However, extracting kerogen from shale rock and denitrogenating the jet fuel are energy-intensive steps compared with petroleum refining it has been estimated that shale jet fuel could be produced at about 70% thermal efficiency compared with 95% efficiency for petroleum (25). Such a difference represents much higher cost for a shale product. 

ASTM (atmospheric) ASTM D 86 Petroleum fractions or products, including gasolines, turbine fuels, naphthas, kerosines, gas oils, distillate fuel oils, and solvents that do not tend to decompose when vaporized at 760 mmHg... 

Syngas cleanup system - low or high temperature and processes used to remove sulfur, nitrogen, particulates, and other compounds that may impact the suitability of the syngas for specific applications (i.e., turbine and fuel cell for electric power generation, hydrogen production, liquid fuel production, or chemical production). 

Nuclear magnetic resonance spectroscopy has been developed as a standard method for the determination of hydrogen types in aviation turbine fuels (ASTM D3701). X-ray fluorescence spectrometry has been applied to the determination of lead in gasoline (ASTM D2599) as well as to the determination of sulfur in various petroleum products (ASTM D2622, D4294). 

Thomas, K.P., and Hunter, D.E. 1989. The Evaluation of a Coal-Derived Liquid as a Feedstock for the Production of High-Density Aviation Turbine Fuel. DOE Report DOE/MC/11076-2993. United States Department of Energy, Washington, DC. 

A brief outline of the products expected in a demonstration plant and in future commercial plants is shown in Figure 2. In future commercial plants, for example, ethane and propane could be utilized as chemical intermediates and naphtha as a source of chemicals or for production of high-octane unleaded gasoline. Synthesis gas produced in excess of the requirements for hydrogen could be utilized as a source of chemicals as well as a fuel. The fuel oil could be selectively fractionated to produce a middle distillate for use as turbine fuel, light industrial boiler fuel or refinery feedstocks, while the heavy distillate could serve as a fuel oil for large utility boilers. 

ASTM (atmospheric) ASTM D 86 Petroleum fractions or products, including gasolines, turbine fuels,... 

Although SRC s are lower in both sulfur and mineral matter than the coals from which they are derived, these materials will require additional upgrading if higher quahty fuels, such as gas turbine fuels, are desired in the product slate (2). One attractive route for upgrading SRC is an extension of petroleum resid hydroprocessing technology (3). In order to fully understand the chemistry involved in hydroprocessing... 

The processing scheme just discussed uses atmospheric and vacuum residues as its raw material. Recently, consideration has been given to a fuels reflnery concept in which whole crude oil is processed to yield only utility fuels. The processing sequence discussed in this paper would flt quite well into such a processing sequence. A block flow diagram of a fuels reflnery is shown in Figure 9. Such a complex would produce low sulfur-content fuel oil, turbine fuel, and naphtha. The naphtha product could be a raw material for the production of either SNG or petrochemicals. 

Trace elemental analysis can also be used to indicate the level of contamination of middle distillate fuels, e.g. turbine fuels. Metal contamination can cause corrosion and deposition on turbine components at elevated temperatures. Some diesel fuels have specification limits to guard against engine deposits, however they sometimes employ Mo or Ni as a catalyst for the refining process which eventually ends up in the finished products. There are several sources of multi-elemental contamination in naval distillate fuels. Sea water is pumped into the diesel tanks as ballast to immerse ships and submarines. Some oil transport ships have dirty tanks and contamination and corrosive products can also come from piping, linings and heat exchangers. 

Careful control of the precipitation allows the pore size distributions of amorphous materials to be controlled rather well, but the distributions are still much broader than those in the zeolite catalysts. This limits the activity and selectivity. One effect of the reduced activity has been that these materials have been applied only in making middle distillates diesel and turbine fuels. At higher process severities, the poor selectivity results in production of unacceptable amounts of methane (CH4) to butane (C4H10) hydrocarbons. 

The U.S. Navy has been involved for some time in the development of Navy fuels from alternative sources (shale oil, tar sands and coal). As a part of this effort, the Naval Research Laboratory and the Naval Air Propulsion Center have been studying the characteristics of these fuels (.1, 2). NKL and NAPC are currently participating in a program to characterize the products from the Shale-II refining process conducted by the Standard Oil Company of Ohio (SOHIO) at their refinery in Toledo, Ohio. This paper is concerned with a part of this program and is a surrmary of the work on the physical and related properties of three military type fuels derived from shale JP-5 and JP-8 jet turbine fuels, and diesel fuel marine (DEM) (3, 5). Another paper of this symposium (6) will discuss the chemical characterization of the fuels. 

SHALE OIL PRODUCTS VS PETROLEUM PRODUCTS TURBINE FUEL... 

---