Measurement the Solid Flux in a Circulating Fluidised Bed By ECT and Microwave Dopplor Method

Circulating fluidised bed (CFB) combustion technology combined with a high efficiency gas-solid separation circulation is one of the key factors to reducing air emissions and the effect on global warming. To scale up a CFB from small scale to large scale, it is important to investigate the solids distribution in the CFB system. In this paper, electrical capacitance tomography (ECT) and Microwave Doppler method are used to measure the solids flux in the standpipe in a circulating fluidized bed with four cyclone separators. An ECT sensor with eight electrodes microwave antenna was mounted outside of the standpipe to measure the solids concentration and solids average velocity respectively. The total solids flux re-circulated to the bed was calculated based on the solids concentration and velocity. The operation parameters including fluidization flux and initial materials load were investigated. The measured result is compared with conventional solids flux measurement methods.