Zero Ammonia Catalysts for Abatement of NOx and Other Species With Waste Minimization

The abatement of nitrogen oxides (NOx) from combustion sources traditionally has been conducted by selective catalytic reduction over vanadia-titania with an ammonia reagent. However, this presents requirements and associated costs for ammonia use and storage as well as loss due to ammonia slip. This Phase I research project addresses the removal of NOx without ammonia in the presence of sulfur oxides using new metal oxide/sulfate and select metal nitride catalysts for the direct decomposition of NO and passive reduction with exhaust-borne oxidizable species. Eltron Research, Inc., previously demonstrated direct decomposition to nitrogen under realistic conditions (in oxygen) as found in exhausts of natural gas-fired sources. However, such catalysts have shown intolerance toward the high levels of sulfur dioxide found in exhausts of diesel and coal-fired power sources. Consequently, it is the objective of this research project to develop catalysts tolerant to levels of sulfur oxides found in these power sources. The catalysts will be applied to exhaust streams containing NOx, CO, hydrocarbons, toxic air pollutants, and oxygen (from 0 to 20 vol%) as well as water, CO, and SO2 (10¿5,000 ppm). These streams will be representative of exhausts from fixed and mobile power sources utilizing hydrocarbon fuels. Such materials would represent a revolutionary, rather than incremental advance in environmental catalysis and compliance. Successful completion of this project will result in the development of catalysts applicable to a zero ammonia technology for the removal of nitrogen oxides and other species from exhaust streams rich in sulfur oxides. Modifications of the catalysts will be applicable to catalytic combustion processes, as well as to the removal of volatile organic compounds and hazardous air pollutants.