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What began as a small in-house laboratory experiment to find a way to use discarded coal products called "fines" has now led to a full-scale demonstration that can boost coal operator profits, reduce waste at their plants, and recover valuable energy sources.

In full-scale tests conducted by CQ of Homer City, Pennsylvania, the GranuFlow process - which was developed and patented by scientists at the Office of Fossil Energy's National Energy Technology Laboratory (NETL) - has been shown to recover and clean a significant portion of coal fines.

Although other methods are available to capture coal fines, these processes become less efficient as particle sizes decrease. The fines captured through these processes also have a high moisture content, which can reduce their heating value and cause materials handling problems, such as sticking in bins and freezing in winter.

The captured fines can be thermally dried, but the process is expensive and energy intensive; moreover, a significant proportion of thermally dried fines can literally blow away with the wind.