Researchers continue to study alternative fuels for aviation

Aviation International News » March 2010
February 24, 2010, 6:48 AM

As government and industry plan for more environmentally friendly energy sources, companies continue to invest in and research alternative fuels for aviation. The U.S. Air Force, one of the government’s largest consumers of fuel, for example, has set a goal that 50 percent of its fuel purchases be composed of domestic synthetic fuel blends by 2016, while IATA has presented a target of 10-percent alternative fuel use for its members by 2017.

In addition, President Obama last month announced a series of steps aimed at boosting biofuel production, including a recently finalized EPA rule to implement a long-term renewable fuels mandate of 36 billion gallons by 2022, with nearly two thirds of that amount to come from advanced biofuels.

As part of its mandate to rely less on foreign oil, the U.S. Air Force has awarded the University of Dayton Research Institute (UDRI) a nearly $50 million grant to develop advanced synthetic fuels and new combustion technologies. A follow-on from the $10 million Air Force grant the institute received in 2008 to lead the design, development and operation of the Assured Aerospace Fuels Research Facility at nearby Wright-Patterson AFB, this six-year endowment will fund exploration in key areas of the development and production of alternative fuels, including blends created from a variety of feedstocks.

“Advances in fuels and combustion technologies are critical to advances in aerospace propulsion systems for 21st-century military and commercial aircraft,” said Dilip Ballal, head of UDRI’s energy and environmental division and director
of the institute’s von Ohain Fuels and Combustion Center. “Our focus will be to design new and improve existing technologies that will not only meet the demands of evolving aircraft systems, but will do so with minimal environmental impact.”

The two major commercial airframers have each recently joined partnerships to continue biofuel flight-testing programs. In January Airbus announced it would support a biofuel joint development program led by Qatar Airlines, Qatar Science & Technology Park and Qatar Petroleum. Known as the Qatar Advanced Biofuel Platform, the program is aiming to develop a detailed plan to produce a biofuel economically and sustainably for Qatar Airlines as the initial end user. Around the same time, Boeing unveiled a similar partnership with Etihad Airways, Honeywell’s UOP subsidiary and the Masdar Institute of Science and Technology. The Sustainable Bioenergy Research Project will focus first on initiatives that use the arid saline-rich environment of Abu Dhabi in new saltwater farming practices. “The paradigm for energy supply is shifting,” said Jennifer Holmgren, vice president and general manager of Renewable Energy & Chemicals for Honeywell’s UOP. “To meet the growing demand for energy worldwide, we must identify regional biofuel solutions that are not only sustainable but can actually regenerate the ecosystems where they are generated.”

A major goal of the URDI program will be to develop and field test new fuels from a variety of sources, including biofuels derived from renewable domestic sources such as seed and plant oils, animal fats and algae. In addition to sustainability, the research will look at the fuels from a molecular perspective. “If we can develop new fuels ‘from the ground up’ at the molecular level, then we have the opportunity to tailor them to meet a variety of needs,” said Ballal, noting that the next-generation fuels could be made to withstand a much wider range of temperatures [than current biofuels], lowering the temperature at which the fuel freezes or permitting engines to run more efficiently at higher temperatures. Another benefit of tailored fuels could be to reduce the levels of carbon deposits remaining inside the engine after combustion. By altering molecular structure, the fuels could also incorporate additional properties potentially eliminating the need for expensive additives.

Biofuel Challenges

“There is still a lot of research to be done,” Ballal told AIN. “Some of the synthetic fuels do not have as good a lubricity as conventional fuels, which can create problems with high-pressure fuel pumps.” Another area of research involves exploring the shelf life of the biofuels. “The storage stability of biofuels is not as good as that of conventional fuels because the biofuels have a lot of organic matter, and organic matter reacts with oxygen. If you store this fuel for one week, then one week later you might have a different fuel,” Ballal said.

Despite clamor for the eventual production of enormous quantities of alternative fuels, mass production is still on the horizon. Last September, ASTM approved the first part of specification D7566, which includes the use of blends of synthetic hydrocarbons produced through the Fischer-Tropsch gas-to-liquid process. Currently under review at the subcommittee level is the specification for blends using hydro-treated renewable jet (HRJ) fuel, which uses hydro-processed fats and oils, including fuels derived from feedstock crops such as jatropha, camelina, salicornia and algae. While the end products of the two processes are similar enough to be grouped under the same specification, the committee has not yet voted on the HRJ fuel specification. “We’re shooting to get it done this year,” said George Wilson, ASTM’s vice chairman for emerging aviation fuels. “Aviation by nature is a pretty conservative body. I would expect some time next year it would be allowable.”

Once that specification is set, according to Ballal, it will open the doors for industry and even investors to start building processing plants to convert these different types of fuel stock into jet fuels. “Basically the Department of Defense has said, ‘If you guys in the industry want to produce the fuel from whatever source you want–coal, biomass, shale, tar sand–you can produce that fuel using whatever process you want as long as the final product falls within these specifications and will be safe to use in aircraft fuel systems and engines,’” Ballal said. “Industry has been waiting for these specifications, and they are almost here.”

In the meantime, the biofuel industry waits. “It’s a little unlike most early stage businesses because you can’t sell anything,” said Mitch Hawkins, CEO of integrated biofuel supply chain manager Biojet. “You can sell it only after ASTM International certifies it for use, so there’s no purpose in going out and making fuel right now.” Biojet hopes to have its infrastructure in place soon to begin biofuel production. Last year the company signed an agreement to deliver four million barrels of biojet fuel once the specification is approved.

Over the past year, using small “designer” batches of fuel produced by refinery technology licensor UOP, several airlines including Air New Zealand, KLM, JAL and Continental made successful flights using alternative fuel blends to power one engine. A planned demonstration flight scheduled for the first quarter of the year by Mexico’s Interjet, using a fuel blend derived from salicornia, was recently postponed after the feedstock supplier failed to provide enough of the aquatic plant to produce the necessary amount of fuel.

“The key difficulty with biojet fuel is there’s really no financing available for feedstock producers,” said Hawkins. “Our estimate is that it is going to take about $20 billion in capital expenditure to get all that feedstock growing and being produced. We’ve had this world financial crisis for a couple of years now, and there’s little capital available.” Hawkins believes it will take an additional $20 billion in capital investment for the biofuel infrastructure needed to meet IATA’s 2017 goal. The USDA is considering a proposal that calls for a Biomass Crop Assistance Program to fund the biomass for conversion to biofuels.

In December, the U.S. Departments of Energy and Agriculture announced the award of more than $600 million in grants to fund advanced biofuel projects. Among the beneficiaries was Los Angeles-based Rentech, which received a conditional grant of more than $22 million for installation of a Clearfuels Technology biomass gassifier. Designed to synthesize wood waste and sugarcane feed stocks, the unit will be installed at Rentech’s Denver product demonstration unit as part of the process to produce drop-in synthetic jet and diesel fuels eventually. When it goes on line late next year, the facility is expected to serve as a test model for larger-scale commercial production refineries. Rentech, along with Seattle-based AltAir Fuels, recently announ- ced it had signed non-binding agreements to provide millions of gallons of renewable jet fuels to a number of airlines.     

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