It’s a Dirty Job… The bivi-TEC® Screen in Coal
Coal is not easy to screen. The specifications are tight, the material is wet, tonnages are high, and down time is not an option when you need to continuously feed a power plant. The bivi-TEC® screen is ideally suited for these conditions and is currently being used across the Coal Belt as the go-to equipment for separating fine material without using water.
The very first bivi-TEC® screen in America was in waste coal. If run-of-mine coal is difficult to screen, waste coal (gob, culm) is downright nasty. A mixture of coal, silt, clay, and soil, typical waste clay is mined from abandoned settling ponds at closed mines. This material may have been sitting in place for 40 years or more and every truckload of material has slightly different physical characteristics, from gradation and ash content to moisture and BTU value. Conventional wire cloth decks aren’t made to handle this kind of variability, and routinely have to be shut down to clear the decks which have quickly become blinded over.
The unique action of the bivi-TEC® screening deck eliminates blinding by accelerating the coal particles up to 50G’s. This not only keeps the openings free from pegging, but also helps to break up the clumps of waste coal, liberating the fines and allowing them to fall through the screen openings.
The cost savings of eliminating water from the screening deck cannot be overstated. Coal processors get a bonus when using dry screens, in that the final coal product is sent to a boiler furnace. The lower the moisture level of the coal fuel, the more BTU’s can be extracted from the coal. Energy is not wasted burning off water, making for a big spike in boiler efficiency.
Arch Coal in Colorado, Foster Wheeler in Pennsylvania, Sunnyside Cogeneration in Utah, and many others use multiple bivi-TEC® screens to process high tonnages of coal 24/7, keeping the power plants up and running year-round and ensuring that your house has heat and the lights stay on.