Journal of Microwave Power and Electromagnetic Energy (JMPEE)
TITLE	Microwave Technique for the On-Line Determination of Moisture in Coal [PDF]
AUTHORS	N. Cutmore, D. Abernathy and T. Evans 1989 24 2 79-90
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Abstract An investigation has been carried out to compare the suitability of microwave transmission techniques, based on the determination of attenuation/mass-per-unit-area, phase shift/shift mass-per-unit-area and attenuation/phase shift for the on-belt measurements of moisture in coal. Preliminary measurements were made on a range of Australian coals packed in waveguide sections. A prototype non-contacting microwave gauge as been designed for the on-belt measurement of moisture in coal, in which a phase shift and attenuation are determined using an 8-port junction. Measurements on a range of coals in layers of 50 to 250 mm thickness and 0 to 15 wt% moisture indicate that moisture can be measured to better than 0.37 wt%, from a determination of phase shift/mass-per-unit-area, using this gauge. The influence of sample packing density, ash content, and material temperature on measurement accuracy has been determined. Key Words: Microwave measurements, dielectric properties, moisture measurement, on-line measurement, coal.