Plasma-Assisted Catalytic Reduction of NOx from Stationary Diesel Engines.

摘要

Diesel engines are widely used throughout the Department of Defense (DoD) for powering tactical and non-tactical vehicles and vessels, off-road equipment, engine generator sets, aircraft ground-support equipment, and a variety of other applications. Current and proposed air pollution regulations are expected to impact the use of these diesel engines. Current catalyst technology is capable of reducing particulates, carbon monoxide and hydrocarbons (HCs). No satisfactory solution currently exists for nitrogen oxides (NOx). For more than a decade, investigators have been searching for suitable catalysts that can selectively reduce NOx in the presence of a reductant. The process is known as selective catalytic reduction (SCR). Such a technology, using ammonia as a reductant, does exist. However, the use of hydrocarbons such as diesel fuel or jet propulsion fuel as a reductant is a more feasible, cost-effective, and environmentally sound approach, particularly for mobile applications. The search for effective and durable SCR catalysts that work with HCs (also known as lean-NOx catalysts) in diesel exhaust environments is a high-priority issue in emissions control and the subject of intense investigations by engine and catalyst companies, and universities, throughout the world. More than 50 lean-NOx catalysts have been reported in the research and patent literature. However, important unresolved technical and economic problems have plagued these catalysts and prevented their widespread application. An approach for resolving the most important of these problems catalyst durability in the presence of soot, fuel sulfur and high-temperature water vapor has been developed by Lawrence Livermore National Laboratory in collaboration with Cummins Engine Company and Engelhard Corporation. The process is known as Plasma-Assisted Catalytic Reduction (PACR). In this SERDP project, the Air Force Research Laboratory and Lawrence Livermore National Laboratory team conducted feasibility testing of the PACR process using laboratory, pilot-scale and full-scale prototypes.