Problem
An innovative Michigan power supplier wanted to reduce surface dust and airborne particles and reduce cleanup time at its PRB coal operation. Coal at the facility is fed either by rail, with a dumper that inverts the car and empties it directly onto a feeder conveyor, or with front loaders working off stockpiles in the yard. Both methods have the potential to generate dust, which would accumulate on flat surfaces and was sometimes visible in the air.
Solution
As part of a larger program to overhaul critical parts of the conveyor system, plant officials researched several options to deal with dust issues. As a first step, Martin Engineering installed a primary cleaner on the belt. Carryback tests showed an improvement of more than 50%. Members of the utility staff discussed the Washbox™ option with Martin, identifying it as a possible solution. Because of the physical properties of PRB coal, the two companies collaborated on design modifications to suit the specific fuel and operating conditions. Changes included such features as special filtration to allow the utility to use a non-potable water supply instead of city water and adding a hose line to each washbox to facilitate cleanout.
Results
Once the Washbox™ was installed and modified, the results were quickly apparent. The carryback test revealed that together the primary cleaner and Washbox™ delivered a 99% reduction in estimated dry weight carryback. Visible dust in the air has been virtually eliminated and dust cleanup has been dramatically reduced. “It’s paid for itself many times over.” The utility’s insurers also approved of the upgrades. “Our provider called it the cleanest facility of its type that he’d ever seen.”