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CleanAir particulate filter system passes US MSHA NO2 tests

8 January 2003

Santa Fe, NM-based CleanAIR Systems announced that its new diesel particulate filter system for the control of diesel particulate matter (PM) emissions in underground mines has passed emission testing by the US Mine Safety and Health Administration (MSHA). The CleanAIR PERMIT™ FBC filter system demonstrated over 85% reduction in PM emissions without increasing nitrogen dioxide (NO2) emissions.

Catalytic passive particulate filters which use high loading of platinum catalyst are known to increase the proportion of NO2 in the total NOx emission. MSHA requires that emission control equipment to be used in underground mining in the USA. be tested for the NO2 activity. Devices that increase NO2 levels are not allowed in underground coal mines. It is possible that NO2-increasing devices will be also disallowed in non-coal mines. One of the strategies to avoid NO2 emissions is to use uncatalyzed or lightly catalyzed filters in combination with fuel additives (“fuel borne catalysts”) to support filter regeneration.

CleanAIR Systems developed a precious metal catalyst coating that does not increase NO2. The CleanAIR PERMIT™ FBC filter system uses this new catalyst formulation, designated FPA, which is applied to a ceramic filter, and a platinum/cerium fuel borne catalyst (FBC) supplied by Stamford, CN-based Clean Diesel Technologies (CDT). The FPA catalyst also decreases emissions of carbon monoxide (CO) and hydrocarbons.

MSHA conducted tests on the CleanAIR PERMIT™ FBC filter system on a laboratory reference engine and on a unit operating in a mine. MSHA lab tests, conducted on a Deutz F6L 912W engine over the ISO 8178 steady state eight-mode test, indicated the system reduced PM and CO emissions by 89% and 86%, respectively. Standard EPA diesel fuel with 350-ppm sulfur content was used for testing.

Besides mining applications, CleanAIR Systems and CDT have recently supplied the combined CleanAIR PERMIT™ FBC Filter system to refuse trucks, beverage delivery trucks, and stationary engines. CleanAIR Systems and CDT are also conducting field and engine dynamometer testing in support of verification under the California Diesel Risk Reduction Program.

In an earlier testing program, MSHA disqualified a number of catalyzed particulate filters from several manufacturers, which were developed primarily for highway applications. The platinum catalyst used in these products is very active in facilitating the filter regeneration, but produces amounts of nitrogen dioxide deemed unacceptable for underground mine applications. Two other products that have passed MSHA tests include another filter with fuel additive and a base metal catalyst filter.

Source: CleanAIR Systems