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NOx Adsorbers

6 May 2003

Mountain View, CA-based Catalytica Energy Systems, Inc. announced that it has signed test agreements with two undisclosed heavy-duty diesel engine manufacturers to evaluate its diesel fuel processor technology designed to enhance the performance of NOx adsorbers on heavy-duty diesel engines to provide a 90% reduction in NOx emissions.

The Catalytica diesel fuel processors are being developed as a potential technology to help meet the US2007/2010 emission standards for truck and bus engines. Following laboratory tests of sub-scale prototypes, Catalytica manufactured two full-scale prototype diesel fuel processors that will be used in an initial round of OEM tests scheduled to be carried out over the next several months.

NOx adsorbers require periodic regeneration under rich exhaust gas condition, during which the stored NOx is catalytically reduced to nitrogen. One of the exhaust gas enrichment methods is to inject diesel fuel upstream of the adsorber. The Catalytica fuel processor facilitates chemical changes in the diesel fuel used to regenerate NOx adsorbers. The fuel processor produces reactive reductants which enable more efficient adsorber regeneration, resulting in higher NOx conversion and less fuel economy penalty of the system.

For the past two years, Catalytica has also been developing an emissions control system for retrofitting heavy-duty diesel engines. The typical retrofit system includes the fuel processor, a diesel particulate filter and an active lean NOx catalyst. The lean NOx catalyst would use diesel fuel reformed by the processor as a NOx reductant. According to Catalytica, the processed mixture of gases can provide higher NOx conversions than those achieved using unreformed diesel fuel. Catalytica is developing both the fuel processor and lean NOx catalyst for the retrofit system. Further announcements are expected later this year.

Catalytica has been developing the diesel fuel processor technologies based on its experience with catalytic combustion systems for gas turbines and with fuel processors to generate hydrogen for fuel cells. The company filed two US patent applications covering the above systems relating to “Devices and methods for reduction of NOx emissions from lean burn engines”. The applications (No. 10/309,936 and 60/426,604) will soon be published by the patent office.

Source: Catalytica