Green Jet Fuel Critical for U.S. Military & Energy Independence

As noted in this core source article, at the Aerospace and Defense Supply Chain Conference held this week in Phoenix, Arizona, it became even more clear that green biofuels are of the utmost necessity for the United States to reduce its dependence on foreign oil. Interestingly enough, oil consumption for aircraft, ships, ground vehicles and facilities makes the U.S. Department of Defense (DOD), and namely the U.S. military, the single largest oil consumer in the world.

According to the U.S. Defense Energy Support Center Fact Book 2008, the U.S. military annual fuel consumption was approximately 200 million barrels, which is about 100 million barrels more than the average for peacetime operations. Suggestions were offered in presentations during the recent Aerospace and Defense Supply Chain conference for reducing oil consumption in both military, space and commercial aircraft including: hydrogen fuel cell technology, greener jet fuel and rocket propellants, and improved FAA traffic management control, as is being tested at several locations during its pilot program, since a great deal of fuel is burned on the runway while planes wait for take-off or landing at commercial airports.

Based on 2008 DOD statistics, 56 percent of the department’s fuel budget was designated for the U.S. Air Force, since it retains the largest number of aircraft. On an annual basis, “mobility” type fuel, used in aircraft, ships, and vehicles, typically accounts for 75 percent of total DOD energy consumption. Thus, fuel used to heat and power buildings and facilities accounts for about 25 percent of DOD energy usage. In terms of fuel types, jet fuel accounts for 58 percent of mobility fuel; however, it is also used in non-aircraft platforms such as tanks, ground vehicles, and power generators. As the country pursues new Recovery Act programs associated with both residential and government green building retrofits and as U.S. military installations such as Ft. Irwin in California and Ft. Hood in Texas incorporate solar power, one of the main issues is to develop a cleaner liquid fuel energy source than oil, possessing significantly lower carbon emissions.

As a result, the private sector is seeking partnerships to investigate greener solutions to this issue, which may be considered one of national security, since it is tied to national defense. Honeywell is part of a consortium of aviation companies, major airlines and engine manufacturers that have been testing bio-based, green jet fuels. This company's aerospace division based in Phoenix, AZ has been evaluating a blend synthesized by UOP LLC, a Honeywell subsidiary based in Des Plaines, Ill., which is composed of 50 percent jatropha and algae-based biofuel, and 50 percent petroleum-based fuel. The engine tests included evaluation of combustion characteristics and a full-engine test for the TPE331 turboprop engine.

This innovative biofuel was produced using oil from algae and jatropha, two sustainable, second-generation sources that are not directly associated with food, land or water resources. In order to synthesize this biofuel, hydrogen is added to remove oxygen from the biological feedstock resulting in a pure, bio-derived hydrocarbon fuel that can be integrated with petroleum-based fuel. Basic energy efficient technologies or design being implemented for housing and government buildings is a lower tier priority for the complex market of commercial and military aircraft due to the high cost of fuel consumption. Moreover, it is much more challenging to develop more fuel-efficient jet engines, for reducing propellant consumption, than gasoline automobile engines, as has been mandated by 2016 for new U.S-sold automobiles in terms of fuel economy and emissions. Thus, developing a non-petroleum-based biofuel alternative is truly essential.

The UOP bio-jet fuel process technology was actually developed in 2007 under a contract from the U.S. Defense Advanced Research Projects Agency (DARPA) to produce renewable JP-8 fuel for the U.S. military. Since then, ongoing demonstration flights have occurred using Boeing, Air New Zealand, Continental Airlines and Japan Airlines aircraft. According to Honeywell public statements, the biofuels tested met or exceeded performance specifications for petroleum-based jet fuel and displayed no negative effects on any of the aircraft systems. In addition, the overall biofuels industry, including that which is dedicated to automobiles, received a boost from numerous Department of Energy allocations through several stimulus programs.

Other more basic research studies are occurring at the university level. For instance, Purdue is working with NASA, the Air Force Office of Scientific Research and Pennsylvania State University to develop aluminum-ice, also referred to as ALICE, which was used earlier this year to launch a 9-foot-tall rocket. The vehicle reached an altitude of 1,300 feet over Purdue's Scholer farms, about 10 miles from campus. Researchers are developing a new type of rocket propellant composed of a frozen mixture of water and "nanoscale aluminum" powder that is considered more ecological than conventional propellants and could be manufactured on the moon and Mars. 

Historically, many past basic research projects from NASA led to commercial green energy technologies, and most satellites and spacecraft utilize solar cells for power. However, just as the U.S. Congress is considering a major overhaul of the solar industry in the U.S. Solar Roadmap Act, it will likely require similar legislation to catch up to countries such as Brazil, who leads the world in biofuel research and deployment. The clean energy race is a global competition, and China is ramping up in all branches of green energy.

The implementation of nanotechnology in using aluminum nanoparticles, which have a diameter of about 80 nanometers, or billionths of a meter, is key to the propellant's performance. These nanoparticles combust more aggressively than larger particles and enable better control over the reaction and the rocket's thrust; better yet, it is considered a green propellant, since its exhaust is mainly hydrogen gas and aluminum oxide, which are not harmful to the environment. In comparison, each space shuttle flight consumes about 773 tons of the oxidizer ammonium perchlorate in the solid booster rockets; as a result, approximately, 230 tons of toxic hydrochloric acid is released in the exhaust, not to mention the enormous greenhouse gas emissions that went into the processing and refinement of the propellant.

ALICE generates thrust through a chemical reaction between water and aluminum. As the aluminum ignites, water molecules provide oxygen and hydrogen to stimulate the combustion until all of the powder is consumed. As innovations in nanotechnology have emerged over the last decade, manufacturers have improved the nano-aluminum particle growth process in terms of throughput, yield and cost.

One of the key requirements at this time is that the fuel needs to be in solid, frozen form. This is critical for it to remain intact while being subjected to the forces of the launch and also to prevent a reaction prior to planned ignition. However, future work will focus on creating a gelled fuel using the nanoparticles, that would ultimately be more analogous to current liquid propellants, enabling control over the rate at which the green fuel is pumped into the combustion chamber to throttle the motor and increase the vehicle's distance. In other possibilities, a gelled fuel also could be mixed with materials containing larger amounts of hydrogen to run hydrogen fuel cells in automobiles.

Biofuels can lower life cycle carbon dioxide emissions relative to conventional petroleum-derived jet fuels, lowering the carbon footprint of aviation and therefore improve local air quality around airports- but more importantly reduce America’s dependence on foreign oil, which would enhance both its national and economic security.

 

This author consults with leading institutions through GLG