Low Cost NOx Abatement in Off-Road Sources

Nitrogen oxides (NOx) contribute to the formation of ground level ozone, aerosols, and acid rain. Considerable progress has been made in reducing emissions from stationary and highway sources. New emissions standards will require that new off-road (non-road) diesel engines achieve emissions of NOx and other species comparable to those from on-road sources. Currently, there are no inexpensive, effective retrofits for either source category. This proposed Small Business Innovation Research (SBIR) Phase I project will apply certain aspects of Eltron Research & Development¿s (Eltron) new catalytic technology for reagent-free abatement of nitrogen oxides (which provides both direct decomposition and passive lean reduction activity) to off-road diesel engine exhaust. A number of NOx abatement technologies (e.g., urea and hydrocarbon reduction) exist, but employment in mobile sources is impractical. These approaches are expensive, provide unacceptable performance, require additional hardware, and impose costs for reagent use and storage, and waste resources (urea or fuel). Consequently, an effective (i.e., displaying > 25% removal) reagentless (passive) lean NOx catalyst is attractive and is the key objective of the program. Eltron has identified innovative, proprietary catalyst compositions possessing exceptional activity for NOx removal from diesel exhaust. This catalyst does not require a supplemental reductant and has given activity in diesel exhaust, which easily surpasses the target activity and Tier 3 standards for off-road diesel engines. It is superior to competing passive lean NOx catalysts and comparable to existing hydrocarbon (and urea) selective catalyst reduction (SCR) strategies at an estimated current cost of approximately $350 (versus approximately $1,400 for a catalytic NOx trap) for a heavy off-road diesel engine. Phase I will identify the best catalyst for the application, optimize the catalyst, and test it in real exhausts, resulting in a retrofit catalyst that outperforms existing technologies while minimizing cost. At the conclusion of Phase I, Eltron will have demonstrated the feasibility of zero ammonia diesel exhaust after-treatment technology for NOx abatement. The technology also will be applicable to exhausts from lean burn gasoline engines, natural gas-fired boilers and turbines, and coal-fired combustion sources. At the conclusion of Phase II, Eltron anticipates that, working with a catalyst manufacturer, a prototype system for field application will be completed.