Journal of Microwave Power and Electromagnetic Energy (JMPEE)
TITLE	On-Conveyor Determination of Moisture in Coal [PDF]
AUTHORS	N. Cutmore, T. Evans and A. McEwan 1991 26 4 237-242
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Abstract A non-contacting microwave transmission gauge as been developed for on-conveyor determination of moisture in coal. Moisture is determined from a swept frequency measurement of microwave phase shift using an 8-port junction, over the range of 2.8 GHz to 3.8 GHz, and a measurement of coal mass-per-unit area from a nuclear transmission gauge or a belt weigher. A laboratory evaluation has been completed on a range of (< 5 mm) and coarse (< 50 mm) coal samples from New South Wales coal washeries. An industrial prototype of the microwave moisture gauge was installed at Howick coal washery, New South Wales, in April 1989 for on-belt determination of moisture in the total washery product. The moisture content of the coal has been determined from a measurement of microwave phase shift by the microwave gauge and coal mass-per-unit area by a Coalscan 3500 ash monitor. The on-line collaboration indicates that moisture can be determined to better than 0.46 wt% for the range of coal types and bypass/washed coal mixtures output from the washery. The prototype gauge is undergoing a long term trial at Howich washery during 1990-1991. The CSIRO gauge was licensed to MCI Ltd. In July 1990 and is now commercially available. Key Words: Microwaves, Moisture, Coal, Phase Shift.