Microwave Techniques for On-Line Determination of Pulverised Coal Mass Flow

The CSIRO Division of Mineral and Process Engineering has been investigating the use of microwave techniques for the on-line determination of the mass flow rate of pulverised coal in coal-fued power stations. Microwave techniques presently under development involve a measurement of microwave phase shift and attenuation to detexmine mass loading, and microwave Doppler shift to determine flow velocity. Laboratory measwments have been conducted on a large closed loop dust rig that is used to simulate flow conditions in a fuel line of a power station. The present paper describes measurements on glass microspheres in this ri4 at mass loadings in the range 0.3-0.8 mg cm and velocities in the range 20-30 ms-'. Tests indicate that the mass loading can be determined to within 12% relative.