On December 3, a Boeing 747 belonging to Air New Zealand is scheduled to take off from Auckland, New Zealand, powered in part by a new type of jet fuel made from a weed. A mixture of equal parts biofuel and conventional fuel will run one of the plane’s engines. The biofuel, which could help reduce carbon-dioxide emissions, was developed by UOP, a Honeywell company that is a major supplier of technology for petroleum refining.
It’s not the first time that an airliner has been powered by biofuel. What’s new is the source of the biofuel: jatropha, a plant that, unlike current sources of biofuels, is not a food crop and can be grown in marginal agricultural land. In the past year, biofuels production has come under fire for contributing to a sharp rise in food prices by diverting grain and other foods for use in fuel. Jatropha provides a potential alternative to soybean oil and palm oil, which are now used as sources of biofuels.
UOP’s new process is part of a larger effort by the company to find alternatives to petroleum, in light of increasing efforts by countries to reduce carbon-dioxide emissions. The company plans to license the technology to refiners, who could easily incorporate it into existing plants, since it’s adapted from UOP’s conventional petroleum refining process. The company developed new catalysts and added a couple of extra steps. For example, jatropha oil, unlike petroleum, contains oxygen. To make the oil into a hydrocarbon compatible with existing refining strategies, UOP included a step to add hydrogen gas, which removes the oxygen. (Other biofuels, such as biodiesel, don’t take this step, which affects the performance of the fuel and can require changes to engines.) The resulting hydrocarbon molecules are then broken into shorter molecules through a common refining process called hydrocracking. During this process, the linear molecules are modified so that they have “kinks in the chain,” says Jennifer Holmgren, the general manager of UOP’s renewable-energy unit. That makes the resulting fuel less susceptible to freezing. The process produces a mixture of primarily jet fuel and diesel fuel.
Unlike many other biofuels, UOP’s jatropha jet fuel can replace conventional fuel without requiring changes to existing engines. Indeed, by several measures, the fuel is better than conventional jet fuel. It has a lower freezing point and can be exposed to higher temperatures onboard a plane without degrading. It also contains slightly more energy than conventional jet fuel, so a plane powered by jatropha could travel farther.