Synthetic Fuel Receives Commitment from USAF

The United States Airforce has committed itself to certify its entire fleet of aircraft for synthetic fuels by 2011. It intends to use synthetic jet fuel for at least one half its jet fuel consumption by 2016. Synthetic fuel is made from biomass, oils from plants or animals, and from fossil fuels such as natural gas and coal.

"We have completely certified the B-52 and B-1" bombers and C-17 cargo planes to fly on synthetic fuel, Strasburg said. In addition, the Air Force has flown F-22 and F-16 fighters, B-2 bombers, KC-135 refueling tankers, C-5 cargo planes and T-38 trainers using a 50-50 mixture of synthetic fuel and standard JP8 military jet fuel.

For testing and certification purposes, the Pentagon's Defense Energy Support Center has been buying synthetic fuel from South African synfuel producer Sasol.

Ultimately, though, the Air Force wants domestic sources, Strasburg said. The intent is to boost national security by reducing dependence on imported oil.

...In January, the Air Force began buying fuel from Rentech, a Los Angeles-based synfuel company that claims to have the only working Fischer-Tropsch fuel plant in the United States.

For now, Rentech turns natural gas into jet fuel at a rate of 10 barrels - 420 gallons - a day at a plant in Colorado. But the company plans to build a plant in Mississippi that will eventually produce 30,000 barrels of synfuel a day from coal, petroleum coke and biomass. Rentech also plans to produce jet fuel from purely renewable feedstocks.

Rentech makes synfuel using the Fischer-Tropsch process. That involves heating the feedstock - coal, petroleum coke, wood, corn stalks or other biomass - to about 1600 degrees Fahrenheit until it turns to gas.

Various unwanted products in the gas, such as mercury, sulfur and others, are removed, leaving carbon monoxide and hydrogen. The [carbon monoxide (CO)] and hydrogen are fed into a reactor where a catalyst of iron particles suspended in liquid wax converts them into a form of synthetic fuel called wax.

The synthetic wax is then refined into jet fuel, diesel fuel and similar products using essentially the same process used for turning petroleum into those products. _DefenseNews

Notice that the process depends upon gasification of carbon sources to syngas (H2, CO, etc), then catalytic conversion of syngas to wax, then to jet fuel. The CO2 byproduct can be captured for productive uses such as oil well recovery and algal biofuels production.

Using biomass as the gasification feedstock results in a more "carbon neutral" process, although as the science and technology improve, the production of CO2 will be seen as a valuable by-product.