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| Rohmac system installed on a diesel-powered locomotive |
Background
Presently, MSHA requires heavy-duty, diesel-powered outby vehicles used in coal mines to be equipped with a diesel particulate filter. For inby diesel-powered equipment, the exhaust temperature is regulated, and thus disposable paper filters can be used in conjunction with either water scrubbers or aqueous heat exchangers. Both of these systems cool the exhaust and reduce the potential for the paper filter to ignite. However, because of the high expense and maintenance problems associated with water scrubbers or heat exchangers, coal mine operators are reluctant to apply these systems to outby engines where exhaust temperatures are not regulated. Options are limited. One is to use high-temperature disposable filters on outby equipment. However, heavy-duty outby vehicles can have exhaust temperatures as high as 1300°F. Due to these high exhaust temperatures, some coal mines have experienced filter fires. The filter itself does not burn, but the solid emissions trapped by the exhaust and other engine hydrocarbons that build up on the filter can ignite. To find practical alternatives to this problem, NIOSH has collaborated with Rohmac, Inc., of Mount Storm, WV, on a project to design, fabricate, and evaluate an exhaust gas cooling device for diesel engines in conjunction with a high-temperature disposable diesel particulate filter for outby use. This device will reduce the exhaust temperature to less than the 650°>F maximum temperature recommended by manufacturers, thereby reducing the possibility of fire and providing a necessary emission control option for coal mine operators. NIOSH researchers are currently evaluating this heat exchanger on a diesel-powered locomotive in an underground coal mine to determine its effectiveness in reducing exhaust temperatures.
Potential Outcome
If this research is successful, it will provide the coal industry with a practical alternative to using paper filters on outby diesel equipment and reduce miners’ exposures to diesel particulate matter. In-mine tests of this system should be completed in early 2006, and the results made available to the industry by late summer 2006.