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DOE - Fossil Energy Techline - Issued on: August 16, 2000 DOE Looks to Small Alaskan Refiner to Apply Biological Process to Meet New Diesel Sulfur StandardsGenetically engineered microbes could offer a possible route to cleaner exhausts from the tailpipes of America's diesel-fueled automobiles and trucks. To find out, the U.S. Department of Energy is preparing to award a research contract to Petro Star, Inc., a small Alaskan refiner that will develop and test a biological approach to removing sulfur from diesel. The Anchorage-based company has been selected to receive $3.2 million in federal funding for the three-year project. The company and its partners will provide another $832,000. Emissions from automobiles and trucks account for nearly 40 percent of the Nation's air pollution. In May, the Environmental Protection Agency proposed a 97 percent reduction in the sulfur content of highway diesel fuel, cutting the current level of 500 parts per million to 15 parts per million beginning in 2006. Removing sulfur from transportation fuels could also help catalytic converters reduce other emissions, since sulfur poisons the converter's catalyst. "Biocatalytic desulfurization" - the process proposed by Petro Star - could provide a way for refiners, especially smaller operators, to meet the more stringent standard much less expensively than is possible with today's technology. Hydrodesulfurization is the current refinery standard for removing sulfur from diesel fuel. The process, however, is costly. It also requires separate facilities to be constructed to generate the large amounts of hydrogen needed to convert sulfur impurities in diesel into hydrogen sulfide. Additional expense is incurred for the facilities to convert the odorous, poison hydrogen sulfide gas into environmentally safe elemental sulfur. A "biocatalyst" process - a system that uses selected strains of microorganisms to remove sulfur in diesel - eliminates the need for hydrogen production and the expense of operating the high-temperature, high-pressure hydrodesulfurization process. Nutrients for the biocatalyst can be supplied by the components of agricultural fertilizers. The nutrients that aren't consumed by the biocatalyst can be removed from the process wastewater by conventional treatment techniques. The major technical challenge is developing a system in which the biological process proceeds rapidly enough to remove sulfur at commercially-acceptable rates and in the presence of oil (which can inhibit the microbial action). Petro Star believes the solutions lie primarily in genetically engineering microbes to boost the rate and activity of the biocatalysts and in designing specialized process equipment that produces a clean diesel fuel and minimizes biocatalyst losses. In the first phase of the project, Petro Star will team with Enchira Biotechnology Corporation (formerly Energy BioSystems Corporation), based in The Woodlands, Texas. The team will work on developing a biocatalyst that can act selectively on the sulfur compounds without degrading diesel quality. The research effort will use a laboratory-scale test unit designed by Energy BioSystems and Vogelbusch USA, Inc., Anchorage, at Petro Star's Valdez Refinery. In the project's second phase, Petro Star and Alaska Anvil, an engineering firm also based in Anchorage, assisted by Vogelbusch, will complete a detailed engineering design for the 5,000 barrel-per-day demonstration plant. At the conclusion of the three-year project, the companies will then make a decision on constructing and operating the demonstration unit. Petro Star, Inc., is a subsidiary of Arctic Slope Regional Corporation. It is the only Alaska-owned refining and fuel marketing operation in the State of Alaska. The small refiner submitted a proposal to the Energy Department's National Petroleum Technology Office as part of a broad-based research project solicitation issued last December. - End of TechLine - For more information, contact: For technical information, contact: Petro Star contact: Jim Boltz, 907-344-2661 |