A New Class of Jet Fuel

Airlines are under serious pressure to reduce greenhouse gas emissions, so when the most prolific oil refinery technology provider on the planet teams up with the world's biggest airplane manufacturer, they produce results-and a new class of fuel.
By Ron Kotrba | November 20, 2009
The effort to "green up" aviation is being taken very seriously, and is well underway. More than a year and a half ago, a task force was put together to investigate alternative jet fuels. Its creation was initiated by the aviation industry to facilitate development of fuel alternatives so private airlines can meet upcoming regulations on greenhouse gas (GHG) emissions; and so the military can gain supply security and cost stability. In September, ASTM International published a new fuel specification for aviation turbine fuels containing synthesized hydrocarbons, D7566.

While D7566 was under development, news reports on aviation testing of a nebulous "biofuel" abounded, even if most of them lacked any real definition of what kind of biofuel this was exactly: bio-derived synthetic paraffinic kerosene (bio-SPK). In June 2007, UOP LLC won a defense department's Defense Advanced Research Projects Agency award to develop and commercialize a process converting renewable feedstocks such as algae into a replacement for Jet Propellant 8 (JP-8) to be used by U.S. and North Atlantic Treaty Organization militaries. In November 2008, Air New Zealand, The Boeing Company, Rolls-Royce and Honeywell's UOP announced a collaboration to demonstrate a 50/50 blend of Jet A-1, the standard commercial aviation fuel, and jatropha-based green jet fuel. In January 2009, Continental Airlines held a demonstration flight using a similar fuel blend in a Boeing aircraft. Later that month, Japan Airlines announced a demo flight using camelina-based SPK. Six months later, 12 representatives of the companies mentioned above, plus executives from Virgin Atlantic Airways, engine maker Pratt & Whitney, GE-Aviation and others, signed a document titled "Evaluation of Bio-Derived Synthetic Paraffinic Kerosenes," displaying acceptance of the research.

A common theme throughout all of those reports was the involvement of UOP, the most prolific oil refinery technology provider on the planet, and Boeing, the world's largest airplane manufacturer. According to Jennifer Holmgren, director of renewable energy and chemicals business unit for UOP, more than half of all the hydrocrackers in operation today are UOP-designed. Hydrocrackers are used by oil refiners to process crude petroleum into transportation fuels utilizing heat, pressure, catalysis and hydrogen. "I have a joke that I tell Boeing all the time," Holmgren says. "I tell them UOP has a unit in every refinery in the world-no refinery left behind," she laughs. "But seriously, UOP has a presence in every refinery in the world, literally." Boeing is the most recognized name in aircraft design and manufacturing. Terrance Scott, a member of Boeing's environmental strategy team, says when it comes to improving aviation's environmental footprint, many options available to ground transportation just aren't feasible for aviation. "We can't go with an electric plane," he says.

Airlines must, therefore, focus on making their planes more fuel efficient and embrace bio-derived synthetic jet fuels to meet future GHG reduction targets, which the EU has in place for 2012 in the form of a cap-and-trade scheme. "Any airplane flying into the EU must demonstrate its GHG reductions," says Mark Rumizen, an aviation fuels specialist with the U.S. Federal Aviation Administration, and chairman of the ASTM synthetic aviation fuel task force. Scott says there are still ways to make airplanes more fuel-efficient, by making them lighter and faster, to fly farther on the same amount of fuel. "For every one pound of fuel saved, that's 3.1 pounds of CO2 not being emitted," he says. But Holmgren says making planes more fuel efficient is not enough to meet upcoming GHG reduction targets. "We must be looking at the fuel itself," she says. According to Scott, however, aviation has a good track record overall-only 2 percent of all manmade CO2 emissions are generated by aviation. He tells Biodiesel Magazine that the aviation industry is targeting consumption of 600 MMgy of bio-SPK by 2015. "That's our goal," Scott says.


The UOP Process

UOP is finalizing commercialization of its process technology for production of bio-SPK, targeted for completion in fourth quarter 2009. UOP is temporarily calling the production technique The Renewable Jet process until a permanent designation is given. The technology is based on UOP's trademarked Ecofining process, a commercially available, licensable technology for green diesel production. While an Ecofining unit can produce up to 15 percent bio-SPK jet fuel as a coproduct of green diesel refining, the Renewable Jet process is designed to boost bio-SPK production to 70 percent by volume. "This is achieved by optimizing the catalytic processes of deoxygenation, isomerization and selective cracking of the hydrocarbons present in natural oils and fats," the company states.

In this line of work, catalysis is everything. Holmgren says UOP's catalysts are proprietary, and small differences in yield output can make big impacts on a technology's profitability. "There once was a time when we were not big into catalysis," she says. "Now, 50 percent of our revenue comes from catalyst supply. See, processes don't change that much, but catalysts continue to improve."

The Renewable Jet process begins with standard oil cleanup procedures to remove impurities. Then, the oil is converted to shorter chain diesel-range paraffins by removing the oxygen and converting any olefins to paraffins by reacting them with hydrogen. Converting olefins to paraffins increases the thermal and oxidative stability of the fuel. A secondary catalytic reaction then takes place, which isomerizes and cracks the diesel-range paraffins (C14-C20) to shorter, highly branched molecules in the jet fuel range (C10-C14).

The resulting fuel is virtually identical to jet fuel with one exception. "It doesn't have any aromatics in it," Rumizen says. "What those do is add density to the fuel, and help maintain proper functioning of the elastomeric seals," also known as seal swell. This lack of aromatics in bio-SPK is why the new D7566 spec only covers up to a 50 percent blend. The petroleum-derived portion of the fuel provides enough aromatics for adequate seal swell.

While Rumizen says the known differences between bio-SPK and conventional jet fuel are well understood, there are a couple of debates going on right now. "One is whether we can we approve a new class of fuel on just the analysis of the final fuel without controlling the process?" he poses. The aviation industry is very conservative when it comes to making changes because of the safety issues involved with flying passengers six miles high. "Do we need to worry about the process?" he asks. "Another area of question is will there be limitations on feedstocks? What about the concern of carry-through of trace materials-like with mercury in fish oil? How do we define process criteria?"

Feedstock

By all accounts, bio-SPK routinely performs as well as or better than JP-8 or Jet-A1 regardless of the feedstock. One of the companies supplying feedstock to UOP for processing is Seattle-based Targeted Growth Inc. Targeted Growth was founded 10 years ago and came together with what the company calls its ground-breaking work in cell-cycle division. The company identified the gene responsible for cell cycle growth and could get cells to divide twice as fast as normal. Subsequently, Targeted Growth licensed that gene to a large seed company.

Tom Todaro, company CEO, tells Biodiesel Magazine his thoughts about working with UOP and Boeing on bio aviation fuel. "It's a huge endorsement," Todaro says. "The implicit endorsement is a reward of time spent, creating feedstock in different applications. Without the time we invested, it would have been hard." As complex as science and agronomy are, he says, they are easy compared to the effective education needed to introduce a new crop. "Growing new crops is about educating growers, farmers, grain handlers, railroads, about best procedures and practices. It's as important as, or more important, than the genetics inside the seed." He says camelina seeds are so small that if the seams on trucks aren't good and tight, for instance, some of the load will be lost.

Camelina, like algae and jatropha, is not a food crop and therefore a better candidate for fuel. Camelina is 60 percent meal and 40 percent oil, and camelina meal was just recently approved as a feed ingredient for livestock. "Economically, that's critical," Todaro says. "It's also a critical component for life-cycle GHGs." Targeted Growth planted more than 100 field-trial plots this year, Todaro says, primarily in eastern Washington, Montana and the Dakotas, with additional plots in Oklahoma and northern Texas. The wide geographical range allows for study of camelina under various water-use conditions, climates and soil types. Targeted Growth compares its yields from year to year to measure improvements, Todaro says, and this year the company is seeing a 15 percent increase over last year.

Bio-SPK from camelina has a freeze point of minus 63.5 degrees Celsius, lower than jatropha SPK at minus 57 C and petroleum Jet A-1 at minus 47 C. Scott says the group is also looking at oil-rich halophytes, or "saline-loving grass," as feedstocks.
Aviation's emphasis to go green could put serious pressure on some biodiesel producers already on shaky financial ground. With a goal to consume 600 MMgy of bio-SPK by 2015, demand for oil and fat feedstocks could cause supplies to shrink and prices to rise. An upside, however, may be a furthering of feedstock development resulting from these partnerships, which would be good news for traditional biodiesel producers and help substantiate bio aviation fuel as a mainstream product.

Ron Kotrba is editor of Biodiesel Magazine. Reach him at (701) 738-4942 or rkotrba@bbiinternational.com
 
 
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