If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



Alternative Jet Fuels Cut Particulate Emissions

Air Pollution: Petroleum substitute could improve air quality at airports

by Kathleen O’Neil
November 11, 2011

Clearing The Air
Credit: U.S. Air Force photo/2nd Lt. Andrew Caulk
An airman checks the fuel connection to an F-15 Eagle fighter jet prior to a flight test of an alternative fuel blend.
JOINT BASE ANDREWS, Md. -- Tech Sgt Anthony 'Tony' Bowman, 113 Wing Logistics Readiness Squadron (LRS), D.C. Air National Guard, fuels up a F-16C Thunderbird aircraft with an alternative bio-fuel blend made up of 50% camelina-based bio-fuel and 50% regular JP-8 fuel.  Over 3,000 gallons of bio-fuel were blended with 3,000 gallons of JP-8 for use by the Thunderbirds during the Joint Service Open House airshow on Andrews AFB, Md, from May 20-22, 2011.  (U.S. Air Force photo by Tech Sgt. Craig Clapper)
Credit: U.S. Air Force photo/2nd Lt. Andrew Caulk
An airman checks the fuel connection to an F-15 Eagle fighter jet prior to a flight test of an alternative fuel blend.

Because of planes’ emissions, large airports are important sources of local air pollution, including fine particulate matter, which can increase people’s risk of heart disease and asthma. Now a study has found that particulate matter emissions from a plane’s engine can fall by almost 40% when researchers blend jet fuel with alternative fuels (Environ. Sci. Technol., DOI: 10.1021/es201902e).

The study tested two types of alternative fuels: biofuels made from animal fat or vegetable oils, and fuels made with the Fischer-Tropsch process, which creates liquid hydrocarbons from coal, natural gas, or biomass. The alternative fuels contain very little sulfur or aromatic compounds, both of which create particulates when burned.

The researchers, led by Prem Lobo, of the Missouri University of Science and Technology, tested the fuels in a jet engine of the same model used in Boeing 737s. Using equipment that captures and measures exhaust, they studied emissions while the engine power was set to 7, 30, 85, and 100% to simulate the engine’s performance during an airplane’s taxi, descent to the airport, climb, and takeoff, respectively.

When the researchers blended the alternative fuels with jet fuel, they found that the more alternative fuel they included in a mixture, the lower its particulate emissions. However, the only fuel that provided adequate power for commercial or military use was a 50-50 blend of Fischer-Tropsch fuel and jet fuel. It reduced particulate matter mass in the emissions by 39% compared to jet fuel. The Air Force, which would like to reduce its reliance on imported oil, has approved the fuel blend for use in 99% of its airplanes.

James T. Bartis, a senior policy researcher at the RAND Corporation, was not surprised by the study’s findings since jet fuels are among the dirtiest fuels sold. Only fuels used on ships contain more sulfur, he says.

But Fischer-Tropsch fuels cost about 20 times more than jet fuel, and are not available in quantities adequate for commercial use, he says. Biofuels are a little less expensive, but have similar supply problems.

The best way to reduce emissions and create healthier conditions around airports, he says, is to enact regulations requiring lower emissions, and to reduce sulfur content in mainstream fuels. Fuel processers already remove sulfur from similar diesel fuels at a cost of “pennies per gallon,” he says.



This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.