Technology office tests synthetic fuel in ground vehicles

  • Published
  • By Damian Housman
  • Warner Robins Air Logistics Center Public Affairs
The Air Force Advanced Power Technology Office here is now conducting research on synthetic fuel for use in a ground environment.

The use of synthetic fuel is vital if the Air Force is to have the means of operating without relying on foreign oil supplies.

The Sept. 19 test flight by a B-52H Stratofortress at Edwards AFB, Calif., is one attempt to demonstrate the feasibility of using synthetic fuel in combat aircraft, and work on synthetic fuel done here at Robins AFB is focusing on synthetic fuel for ground-support vehicles.

The quest for alternative fuel is not new. The Fischer-Tropsch, or FT, synthetic fuel process is named for two German scientists, Franz Fischer and Hans Tropsch, who invented the system prior to World War II. Germany recognized its vulnerability to a cutoff of petroleum supplies, and used the FT system extensively during the war. It is the very same FT system that the Air Force uses in its current effort.

"If oil is cut off for any reason, we need a source of fuel to run military aircraft and vehicles," said Mike Mead, head of the Air Force Advanced Power Technology Office at Robins AFB.

Mr. Mead's work at Robins AFB involves management of the fuel integration program for ground applications, while the Air Force Research Laboratory manages the fuel program for aircraft.

The Fischer-Tropsch process starts with synthesis gas produced from feed stocks such as natural gas, coal or biomass. The FT synthesis process converts synthetic gas into clean burning liquid fuel through a process using heat and pressure.

"Currently we are demonstrating both a 100-percent synthetic fuel and a 50-50 blend of synthetic and petroleum fuel for vehicles and ground equipment applications," Mr. Mead said. The fuel now used in aircraft tests is a 50-50 blend, but the goal is to prove that 100-percent synthetic fuel can be used.

The 100-percent product is slightly less dense than current JP-8 jet fuel, according to project engineer Bill Likos.

"We don't know yet that the difference in density is meaningful," he said.

The two synthetic-fuel compounds are under test by the Air Force. S8 FT fuel, which is used as a substitute for JP-8, is being demonstrated at Selfridge Air National Guard Base, Mich. S2 FT fuel, which is used as a substitute for diesel fuel number 2, is being demonstrated at Edwards AFB.

"Most people were not aware of it, but when the B-52 took off from Edwards, the bus carrying the media and VIPs was powered by S2 FT synthetic fuel. It was a double demonstration," Mr. Mead said. The B-52 used S8/JP8 fuel blend to run two engines, with regular JP-8 running the other six engines.

S8 FT fuel is also being demonstrated in R-11 refueling trucks as well as other support vehicles. One of the lessons learned, according to Mr. Mead, is that no modifications to any vehicles or ground equipment are needed.

"We use the fuel in this demonstration as-is, and don't have to change the vehicle at all in order to use it," he said.

Another advantage to FT fuels, testers are discovering, is that synthetic fuel is cleaner than regular fuel.

"The FT process results in a 90-percent reduction in particulate emissions and an 80-percent reduction in smoke numbers for purified fuel," Mr. Likos said. In tests of the 50-50 blend some smoke is visible, but with the 100-percent FT fuel, no smoke is expected to be seen.

Despite the positive results of synthetic fuel tests, adoption of synthetic fuel is still in the future.

"So far, we have only had Syntroleum Corporation, which makes the fuel, make 10,000 gallons of fuel available at Edwards for test, and another 2,300 gallons at Selfridge," Mr. Mead said. "Thus far, this is a demonstration program, with no manufacturing plants built yet for (mass production of) FT fuel."

Mr. Mead and Mr. Likos said while the fuel is currently produced from natural gas, it can also be produced from coal. The U.S. has vast coal reserves, which would go a long way toward easing the nation's dependence on foreign oil supplies. However, cost may continue to be an issue, even if the synthetic fuel tests successfully throughout the program. Syntroleum estimates if the price of petroleum crude remains at its current highs, FT fuels will be cost competitive.