Permissible diesel-powered equipment operating in underground coal mines must meet temperature requirements and must not emit flames or sparks into the mine atmosphere. The most common device used to meet exhaust control requirements is the water scrubber. Water scrubbers cool the exhaust and remove approximately 30 pct of the diesel particulate matter (dpm), but they are large, require frequent maintenance, and consume large quantities of water. The U.S. Bureau of Mines evaluated a new emission control device designed to meet the safety requirements and control dpm emissions. The dry exhaust conditioning system (ds) cools the exhaust using a fin and tube heat exchanger and removes dpm with a ceramic diesel particle filter (dpf), which is placed downstream of the ds. The objectives of the research were to determine the effect the ds-dpf has on particle emissions, engine performance, and cooling efficiency. Additional objectives were to evaluate an off-board cleaning system and to determine if the ds-dpf is ready for in-mine tests. Laboratory tests indicated that the ds alone removed about 42 pct of the dpm, the dpf alone removed about 91 pct, and when the systems were combined over 97 pct of the dpm was removed. During transient tests, the ds maintained exhaust temperatures below the 150 deg c limit; however, when the engine was operated at rated speed and full load, the temperatures exceeded this limit. This was due to dpm being deposited on the cooling fins, lowering the heat transfer capability.
Proc. American Mining Congress; Pgh, June 20-21, 1989; Washington, DC, 1989, PP. 173-186