Air University Review, November-December 1979

Straw-Colored Gold:

jet fuel from rocks

On a bright Ohio morning on 18 June 1975, a crew headed by Lieutenant General James T. Stewart took special care to prepare T-39 03491, for an early morning departure. The crew chief, Master Sergeant J. Reed, had seen to the preflight activities to include filling the tanks with 935 gallons of jet fuel. At 0833, General Stewart and the other pilot, Lieutenant Colonel O. H. Bradley, lifted the white-over-gray Sabreliner into the sky and pointed the bird on a course from Wright-Patterson AFB to their destination, Carswell AFB, Texas, at Fort Worth.¹ A routine operation? It would seem so because everything went as planned, and they touched down at Carswell without incident at 1055 local time. What was unusual that day was that the JP-4 they burned in their engines was made from rocks. Oil shale from Colorado had been made to give up the crude oil locked in it, and it was then refined into a JP-4 type fuel. As far as can be determined, it was the first flight by a turbine engine aircraft burning fuel made from oil shale rocks.

This flight was an important milestone in the Aero-Propulsion Laboratory's Aviation Turbine Fuel Program. The Air Force Aero-Propulsion Laboratory (AFAPL) and its Fuels Branch have been designated prime for aviation turbine fuels for all the services by the Department of Defense (DOD). This Wright-Patterson AFB unit, in a long-range program by DOD and the National Aeronautics and Space Administration (NASA), had completed with this flight one of the preliminary phases of the synthetic fuels research program.² The fuel was derived from a shale crude oil produced by Paraho, Inc., in Colorado; the Gary Western Refinery, also in Colorado, refined the crude to JP-4 properties. The Aero-Propulsion Laboratory then processed this product to a fully qualified JP-4 fuel, including blending of an anti-icing additive and a corrosion inhibitor. Extensive testing, including engine evaluation, was conducted by the laboratory with the aid of the fuel quality control arm of the Air Force Logistics Command. This preparation was very painstaking, not the routine bulk fuel handling at all. In fact, much of the fuel was filtered for purity by manual methods, gallon by gallon. Yet this is not so important as the fact that the fuel was some of the first produced from a source that is abundant within the continental United States.

The oil shale deposits of the Green River formations in Colorado, Utah, and Wyoming are believed capable of supplying a significant portion of the energy needs of the United States. The U.S. Coast and Geodetic Survey has estimated that these formations contain the equivalent of nearly two trillion barrels of crude oil. Of these, about 600 billion barrels are believed to be in high-grade deposits containing 25 gallons (roughly a half barrel) of raw shale oil per ton of rock.³ The present rate of use of petroleum by the U.S. is 6.6 billion barrels yearly and going up. But also going up is the percentage of that gigantic consumption that comes from unpredictable foreign sources. The year 1977 saw the percentage of imported crude oil and refined products rise to 45 percent on an ever-rising course. It is not hard to see, then, that if the technology for unlocking the oil from these shale deposits is brought to an economically viable level, the U.S. will have an important contribution to its growing energy needs in the years ahead. High among these needs are those for defense, and military fuels were among the first to be extracted from these rocks.

The Honorable John Patrick Walsh gave this highly portentous warning:

There are a number of interrelated aspects to the heavy dependence of the industrialized countries on imported hydrocarbons. The most serious of these is the vulnerability of supply. In the event of major power hostilities, the U.S.S.R. ostensibly would endeavor to cut the oil flow at its sources or to interdict tanker passage. Either would be difficult to prevent. Safeguarding the lengthy sealanes to Western Europe, Japan, and the United States would be a formidable task in the face of Soviet submarines, surface ships, and bombers. This is not an acceptable situation from a national security viewpoint.⁴

Ambassador Walsh speaks with the knowledge of a scholar and a background of experience as the U.S. ambassador to the oil-rich country of Kuwait on the Persian Gulf.

To growing admonitions regarding the fragile conditions surrounding U.S. dependence on foreign oil, former Secretary of the Air Force John C. Stetson said that "before the end of the next decade, the Soviet Union itself will be forced to look outside its borders, if it is to meet its growing oil needs in any economically feasible way."⁵ Speaking of the geopolitical imperatives inherent in this situation, he also stated that "the prospect of obtaining low-cost Persian Gulf crude oil by threat or by military force, and then denying it to the free world certainly has occurred to them." Regarding interdiction of the oil lines of communication to which Ambassador Walsh also referred, Mr. Stetson added, "Equally disturbing is the potential threat to the sea lanes and strategic approaches to the Persian Gulf."⁶

Interruption, by whatever means, of the continuous stream of tankers that bring petroleum to the United States could have serious consequences for the U.S. and its free world friends in the period just ahead. Projection of military power and sustained air operations, if called for by the Chief Executive and Congress in support of national objectives, could be seriously hampered or even precluded if supplies of turbine fuels had to come exclusively or mainly from U.S. domestic sources. For these and other reasons, it seems imperative that the Air Force and the Defense Department give maximum support in the form of policy, money, and manpower to relieve this potential fuel problem.

Growing numbers of research scientists in government and industry have been put on the project by the Department of Defense, Department of Energy, and the Air Force, and they are increasing their efforts to solve this problem for the defense of the country. The flight of USAF T -39 03491 successfully demonstrated one milestone along the road to providing a measure of self-sufficiency in jet fuel. Other milestones have been reached since that event in 1975. However, there is still a very long way to go, and thought should be given to accelerating the process.

Response to the need for domestic sources of aviation jet fuels was initiated in 1974 in a program of the Air Force Systems Command's Aero-Propulsion Laboratory at Wright Patterson. Since that activity had been given prime responsibility for aviation turbine fuels within DOD, an Aviation Turbine Fuels Technology Program was begun to define the properties of jet fuels that would lead to adequate availability and acceptable cost.⁷ In this program two approaches are being pursued. The first is to relax specifications to reduce the level of processing required on conventional petroleum crudes as well as on the lower quality crudes we will have to use very soon. Second is to investigate the acceptability of fuel produced from alternate sources such as coal, oil shale, and tar sands to meet such new and relaxed specifications.

At this point, it is necessary to review the possibilities for alternative jet fuel sources, principally coal liquefaction and oil shale conversion to refinable liquids.⁸ Let us examine briefly these two possible sources of feedstocks for jet fuel refining.

For many years coal liquefaction had held out promise as one solution to the petroleum problem. Actually, in Germany during World War II, the Luftwaffe operated on fuel from liquefied coal. SASOL has been operating a liquefaction plant since 1955 in the Union of South Africa, producing 9000 barrels of oil per day plus other chemicals and fuels at an efficiency of 35 percent in converting coal to useful products. U.S. engineers are aiming for a much higher efficiency of 60 to 70 percent to make the process economically feasible. Since the U.S. has massive coal reserves and one ton of coal can yield one to three barrels of oil, a 'huge, largely untapped source is waiting. Many U.S. firms got involved in the early seventies, but optimistic expectations have become less sanguine as the research proceeds. The high cost of plant construction (with as much as a $1 billion price tag on a plant to produce 50,000 barrels of crude-type oil) and the concomitant high price per barrel of the refined jet fuel product that is not competitive today are major deterrents. With uncertainties on the future pricing of petroleum crudes by the Organization of Petroleum Exporting Countries (OPEC) nations, as well as the pricing of synthetics in the face of a meandering national oil policy, plus environmental protests against the strip-mining, air, and water pollution associated with the process, firms in the industry are reluctant to commit the large investments of risk capital required. Also, Aero-Propulsion Laboratory research has found the use of coal liquids as raw material for refining jet fuel to be less suitable than other sources.

Oil shale, according to Inform, Inc., contains neither oil nor shale but is a mixture of marlstone rock and an organic substance called kerogen. This kerogen was formed in much the same way that crude oil was formed; i.e., sediments from lakes some 50 million years old were pressurized underground. When heated in a retort, the kerogen decomposes into an oil-like liquid. This untreated liquor contains high concentrations of nitrogen compounds, oil-soluble arsenic (a catalyst poison), nickel, iron, sulfur, oxygen, and reduced levels of hydrogen compared to the average petroleum crudes. Adjusting these levels requires costly processing, but the technology exists.

Estimates are that from 25 to 42 gallons of such crude can be squeezed out of each ton of oil shale rock. Considering there are some 25,000 square miles at the juncture of Colorado, Utah, and Wyoming underlaid with thick strata of the substance, one begins to realize the size of the resource and understand why so much emphasis is being directed toward finding economical ways to unlock the oil contained in it. There are many different processes used to accomplish this unlocking, but, in general, they are of two principal kinds.

These two extracting processes are the aboveground retorting method and the in situ or below-ground method. In the surface process, the rock is strip-mined or taken from underground shafts and carried to a large furnace called a retort, where it is heated by oil or gas to above 900.F. At this temperature the kerogen is converted into oil and some residuals. The spent rock must be disposed of in an environmentally acceptable manner. Much water is used in the refining process, part of it to dispose of prodigious quantities of waste rock. The oil shale region is generally water-deficient, and it would be a major undertaking to bring and store water for large-scale processing.

In the below-ground in situ retorting method, the oil shale is left in the ground. Holes, shafts, or chambers are made in the rock formations, the oil shale is broken up by explosives, pressurized water, or mechanical means; then this rubble is ignited underground. Air or oxygen is pumped in to support the combustion at a controlled rate. The portion of the kerogen that is not used as fuel for the combustion is converted by the heat to oil, which is pumped to the surface. The in situ process is more economical of water, and the waste rock disposal problem is diminished. Some contamination of ground waters may result, requiring special treatment.

Air Force Aero-Propulsion Laboratory initiated a joint USAF/NASA-funded contract with Exxon Research and Engineering in 19749 to consider alternative domestic hydrocarbon resources that could be used as the raw material liquids in the refining of jet fuel. In these experiments, hydrocarbon feedstocks produced from three shale conversion processes and two coal liquefaction methods were distilled and hydrotreated. Both coal and shale liquids are deficient in hydrogen atoms that would make them similar to petroleum crude.

"Hydrotreating" is the term used for the hydrogenation process. Hydrotreating is very costly and energy consuming. It is expected to become more so unless a cheap way is found to liberate hydrogen. The conditions of refining of these liquids such as catalysts, temperatures, and pressures were varied. Results showed that all three shale oils produced jet fuel within current specifications by hydrotreating at lower pressures (cheaper) than the two coal liquids. In addition, the coal products were highly naphthenic since they contain very little paraffins to start with. Thus, they can be expected to give some unusual burner can effects as well as smoke emissions. The conclusions of the Exxon study were that, of the two, oil shale is economically and technically closer to commercialization and produces a final product that more nearly resembles petroleum-derived jet fuels than do the coal liquids.

In order to determine the most critical turbine fuel specifications, the relaxation of which would nave a beneficial impact on availability, an AFAPL study was contracted for with Bonner and Moore Associates, Inc.¹⁰ Additionally, they would estimate the effect, if any, that these relaxed specifications would have on the refining industry's willingness to offer jet fuel for sale. Bonner and Moore made an industry survey, the results of which indicate that increases in availability of 20 percent could be realized by relaxing the freezing point and final boiling point. Some assumptions had to be made on the availability of crude, refinery costing procedures, and what effects increased proportions of jet fuel would have on other refinery products in the run. Increases of 28 percent could be gained by relaxing the aromatic content, smoke point, freezing point, and final boiling point under the same assumptions.

AFAPL is conducting studies in-house and through contract to determine the effects on engine components of turbine fuel property variations. Two elements that a future fuel will have in different proportions from the present JP-4 are hydrogen and nitrogen. Future feedstocks such as heavy crudes, shale and coal liquids, and tar sands are all lower in hydrogen and higher in nitrogen content. They also contain traces of metals that have to be processed out. In the Wright-Patterson labs, tests are in progress to determine the effects of varied amounts of hydrogen and nitrogen on combustors (burner cans in the turbine engines). Typical data from these tests show that significant increases in combustor liner temperature (usually associated with reduced life) due to the more luminous flame are produced as hydrogen content is decreased. Higher temperatures generally result in higher smoke numbers. Nitrogen in the fuel results in undesirable emissions and other effects with increases in the nitrogen content.

Three types of burner cans associated with older, current, and new engines are involved, each of which requires fuel of certain properties for best performance and optimum life. General Electric Company,¹¹ under two FY77 contracts, explored the effects that varied hydrogen content, volatility, aromatic type, and end boiling point have on the performance and life of the low pressure (J79) and the full annular type (F101) burner cans. In an FY78 contract, the high-pressure-type burner can combustor was evaluated by General Electric.

During FY78, a Fuel/Engine/Airframe Optimization Study was initiated.¹² The study will first determine the limits to which fuel specifications can be altered without detrimental effects to any Air Force mission or aircraft as well as effects on the cost and availability of such fuels. Second, efforts will be directed toward setting the properties of such fuel so as to minimize life-cycle costs of affected Air Force aircraft and systems. AFAPL engineers expect that the end result will be a tradeoff with fuel properties, cost, and availability on one side and aircraft system life-cycle costs and modification expenses on the other. The results of this study will provide guidelines for an Aviation Turbine Fuel Technology Advanced Development Program set for FY79.

The advanced development program is tailored to provide an interim fuel specification within three years for a fuel that is expected to resemble JP-8 in its properties. Such a fuel might closely resemble the one analyzed in the accompanying table. The program has a timetable that runs through 1990, with significant milestones in 1980-81 and 1985. AFAPL does not expect to bring forth a major change in fuel specifications for ten years by current timetables. These expectations seem very conservative to the layman, but there are limits to the time compression that can be made in necessary laboratory procedures, engine test runs, 'and flight tests. AFAPL experts state that a validated fuel specification will ensure confidence in the projected use of fuel processed from petroleum and from alternate energy sources with respect to engine performance, compatibility with combustion and fuel system components/elements, and the level of harmful emissions. When national priorities are more fully spelled out, one would hope that timetables that favorably meet the world situation will be established.

So far the United States has had only pilot plant operations in the production of crude oil from the oil shale rocks of Colorado, Utah, and Wyoming. Those trillions of potential barrels of oil still await the first full-scale processing plant. The huge efforts required in developing the mining or in situ extraction have not yet been expanded to full operational size, which is normally stated in terms of many plants of 50,000-barrel-a-day production. These huge mining, materials handling, and crude processing ventures require large commitments of risk capital from investors and companies, which need assurance that they will receive a satisfactory return on their dollar investments. Currently 80 percent of the oil shale lands are still owned by the U.S. government and held up by the Department of the Interior Bureau of Land Management. Prodigious amounts of water are said to be needed for these processes as well as environmentally satisfactory solutions to the problem of waste rock disposal. For this, water must be diverted to the area and impoundments constructed. So far, these requirements are only under study.

By way of contrast, our Canadian neighbors have not been unduly inhibited by the huge investments of engineering talent and necessary capital. They have plunged in to develop their special resource. The comparable hard-to-recover tar sand deposits in Alberta along the Athabasca River cover some 30,000 square miles and consist of thick black concentrations of oil tar locked in sand and clay. Estimates of this resource (similar but not the same as ours) run to 300 billion barrels of recoverable crude. Canadian firms began construction of major projects in 1964 and have been producing at the rate of 75,000 barrels daily from these tar sand mines. Associated Press reports that expansion of these extracting operations is now under way with a $2.1 billion investment.¹³ About a dozen other firms are also actively developing the ext1raction of crude from their tar sands.

In light of our current need to import 45 percent of our oil,¹⁴ such a commitment by the United States to the development of a similar domestic resource in our oil shale deposits is of critical dimensions. National defense requirements to mount and sustain air operations in support of U.S. foreign interests and treaties will certainly require indigenous sources of jet fuel if foreign oil is interdicted. The oil shale deposits hold promise of filling that need, at least in part, were they to be fully developed.

Secretary of the Air Force Stetson urged action of a timely nature in this direction:

The U.S. must develop technologies for the economical production of synthetic crude oil and its conversion to jet fuel. A primary objective of this effort should be to ensure an adequate domestic source of aircraft fuel for military operations. At present, synthetic oil production is an expensive process compared to conventional oil production. We should be Willing to pay some premium to get synthetic crude into production and to gain experience with the process, We need to do this now, because some day we won't have cheap natural crude oil. Depletion of our domestic natural petroleum supply is only a matter of time; then synthetic oil will become our only secure source of petroleum.¹⁵

Perhaps it will not be identified by its straw color like JP-4, but it will be as precious as gold to the security and well-being of the country, this jet fuel from rocks.

Notes

1. Marc P. Dunham. Deputy Director. AF Aero-Propulsion Laboratory, Wright-Patterson AFB, Ohio, Information for Brigadier General Hendricks, 18 June 1975, Subject: "World's First Flight on a jet Fuel Produced from Shale Oil" from files of AFAPL.

2. Ibid.

3. These figures compare with other sources and are among those used in a paper presented at the American Petroleum Institute Refining Department, 43rd Midyear Meeting, "Conserving Petroleum--New Feedstocks and Fuels for Refineries," May 10, 1978, Toronto, Canada, by R. F. Sullivan, B. E. Strangeland, and H A. Frumkin of Chevron Research Company and C. W. Samuel of Chevron USA, Pre-Print No. 25-78, American Petroleum Institute, Washington, D.C.

4. See "The Energy Problem in a Global Setting," Air University Review, July-August 1977, pp. 2-14.

5. John C. Stetson, in a speech to the Irongate Chapter of the Air Force Association on 7 December 1977. News Release No. 977, USAF Secretary of the Air Force Office of Information, pp. 5-6.

6. Ibid., p. 6.

7. A. V. Churchill, C. L. Delaney, and H. R. Lander, AFAPL, "Future Aviation Turbine Fuels," Paper No. 78-268, presented at the American Institute of Aeronautics and Astronautics 16th Aerospace Sciences Meeting, Huntsville, Alabama, January 16-18, 1978, p. 2.

8. See Stewart H. Herman and James S. Cannon, Energy Futures Industry and the New Technologies (New York: Inform, 1976). pp. 405-15. The book gives an excellent description of these processes.

9. Churchill, Delaney, and Lander, pp. 28.

10. Ibid., pp. 8-4.

11. Ibid., p. 5.

12. Ibid.

13. "$2.1 Billion Oil. Mining Venture Set for Canada," New York Times, July 25,1978, p. 10.

14. Churchill, Delaney, and Lander, p. 1.

15. Stetson, p. 8. Emphasis added.

Lieutenant Colonel Richard Earl Hansen, USAF (Ret), (M.A., Syracuse University) is a free-lance writer currently working on a novel based on an incident in Air Force history. As command pilot and rated navigator, he logged over 6000 military flying hours, 440 in combat; flew P-38s in the Pacific during World War II, F-51s in the Korean War, and B-47s and B-52s in Strategic Air Command. Colonel Hansen has published articles in many professional journals. At the time of his retirement, he was Acquisitions Editor of the Review.

Disclaimer

The conclusions and opinions expressed in this document are those of the author cultivated in the freedom of expression, academic environment of Air University. They do not reflect the official position of the U.S. Government, Department of Defense, the United States Air Force or the Air University.

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