A Missouri coal-fired generating station needed to reduce coal dust in an onsite tunnel. Approximately 9,000 rail cars of coal pass through the tunnel each month, dumping coal for power generation. The tunnel employed a water misting system that kept down the hazardous coal dust, but the system frequently froze in the winter months. A secondary use for the misting system involved melting frozen clumps of coal, which provides for more even burning. The clumps form when the cars sit outside in the rain or snow in sub-zero temperatures. A new design was needed to prevent the misting system from freezing.
Chromalox recommended employing clean water circulation heaters on the system to maintain water temperature between 40° F and 50° F. The new skid-based design operates allows water to recirculate in a closed loop system. Large fans blow air across heat transfer tubes to evenly distribute heat through the tunnel.