Plant tests of an on-line multiple-pipe pulverised coal mass flow measuring system

The CSIRO Division of Minerals has developed and successfully plant-tested a commercial prototype pulverised fuel (PF) mass flow measurement system on all four boiler feed lines from a single pulverising mill at Bayswater pow er station, in the Hunter Valley, NSW, Australia. The CSIRO PF mass flow me asurement system utilises measurements of the attenuation and velocity of p ulsed beams of 60 kHz ultrasound transmitted across the boiler pipes to det ermine the PF mass flow in each pipe. The system is used to detect non-unif orm distribution of PF between boiler feed pipes. Using this information to balance the burners would lead to improved uniformity of combustion with t he benefits of improved combustion efficiency, improved control of NO, emis sions, reduced boiler tube erosion and reduced fouling and slagging. During calibration of the mass flow measurement system, PF was measured in the ra nge 3.4-5.9% relative in individual pipes when compared with a beta-ray tra nsmission gauge. A comparison of the mill gravimetric coal feed weighers wi th the cumulative PF flow measured by the PF mass flow measurement system s howed agreement to within 1.8% relative over the primary air range 40-90%, (C) 2000 Elsevier Science Ltd. All rights reserved.