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New Technology Removes Sulfur for Ultra-Clean Fuels STATE COLLEGE, Pennsylvania, April 10, 2002 (ENS) - A process that removes organic sulfur from liquid fuels may help refiners provide fuels for fuel cells and meet new clean fuel requirements, say researchers at Pennsylvania State University.
"Currently, the U.S. Environmental Protection Agency (EPA) allows 500 parts per million sulfur in diesel fuel and 350 parts per million in gasoline, but by 2006, the regulations will require only 15 parts per million sulfur in diesel and 30 parts per million in gasoline," said Dr. Chunsan Song, associate professor of fuel science and program coordinator for the Clean Fuels and Catalysis program at Penn State's Energy Institute. "Long before that, however, we will need ultra-clean fuels for fuel cells." Removing organic sulfur from hydrocarbon fuels is difficult because the sulfur is bound to compounds that fuel producers would like to remain in the fuel. Current methods of removing sulfur from liquid fuels use high temperatures and pressure and hydrogen gas. When the new tailpipe and sulfur standards are implemented, Americans will benefit from the clean air equivalent of removing 164 million cars from the road, according to the EPA Office of Transportation and Air Quality. "These new standards require passenger vehicles to be 77 to 95 percent cleaner than those on the road today and reduce the sulfur content of gasoline by up to 90 percent." "These emission reductions will prevent 8,300 premature deaths, more than 9,500 hospitalizations, and 1.5 million work days lost," the EPA explains. The Manufacturers of Emission Controls Association (MECA) has reported that sulfur in gasoline inhibits the emission control performance of catalyst technology by competing with the exhaust pollutants for "space" on the active catalyst surface. "Exciting developments in engine and catalyst technology have occurred and will continue to occur," said MECA executive director Bruce Bertelsen. "To maximize the benefits of these technologies, lower sulfur fuel is needed."
MECA supports the emission standards adopted by the EPA for highway diesel powered heavy-duty engines. Bertelsen says the industry is set to spend over $2 billion by 2010. He is confident the standards will be achieved in a cost effective manner within the lead time provided, "given the availability of diesel fuel with a sulfur level capped at 15 parts per million." The new Penn State process, called SARS for selective adsorption for removing sulfur, works at low temperatures and pressure and does not use hydrogen or other reactive gases. "We have developed a process that selectively adsorbs organic sulfur on to a metal species," Dr. Xiaoliang Ma, research associate, Penn State Energy Institute, told attendees Monday at the spring meeting of the American Chemical Society. "This method will not adsorb the coexisting aromatic compounds like benzene and naphthalene." The researchers hope that refineries can use the new process to remove sulfur and meet future ultra-clean fuel requirements, and that companies providing fuel for fuel cells can use the process to produce ultra-clean fuel. "Fuel cells need essentially zero sulfur fuel to operate," said Song. "Small adsorption sulfur removal systems might be used at gas stations on special clean fuel pumps for fuel cell vehicles to ensure that all sulfur is removed from the fuel. This SARS concept can also be used for on board removal of sulfur from fuel for fuel cell system use." Essentially, a fuel cell functions like a regular battery. Through a series of chemical reactions, the fuel cell is able to convert chemical energy into electrical energy and heat as long as there is sufficient fuel present to supply the reactions, explains Ravi Raman of Penn State. A fuel cell car produces no emissions except water vapor, while a gasoline powered car produces water vapor plus carbon dioxide, nitrogen oxides and unburned hydrocarbons. But the promising technology is still in development for cars, although fuel cell buses have had some successful trials including a current one taking place in Vancouver. DaimlerChrysler has produced a prototype fuel cell car, the Necar, but consumers will not be able to buy fuel cell cars in the open market until 2004. Jürgen Schrempp, chairman of the DaimlerChrysler Board of Management, views the fuel cell as the most promising of all alternative drive systems. "The fuel cell boasts efficiency levels greater than those offered by the combustion engine. It can be used in both mobile and stationary applications, can run on regenerative fuels and has the potential to become the drive of the future," he said. The company intends to invest around $1 billion in the development of this drive between 2000 and 2004. Related Links: Penn State Energy Institute: http://www.energyinstitute.psu.edu/research.html EPA Regulatory Announcement Fuel Sulfur Controls: http://www.epa.gov/OMS/regs/hd2007/frm/f00057.htm Manufacturers of Emission Controls Association: http://www.meca.org/ DaimlerChrysler: http://www.DaimlerChrysler.com/index_e.htm?/environ/environ_e.htm Copyright Environment News Service (ENS) 2002. All rights reserved. |
Dr. Chunsan Song at the Penn State Energy Institute (Photo courtesy 
Big rigs fill up at a truck stop. (Photo courtesy 