Gas-solid Flows Measurement For A Circulating Fluidized Bed With Six Cyclone Separators By Electrical Capacitance Tomography

Cyclone separator is the most important part in a circulated fluidized bed (CFB) boiler. Its performance directly affects the design and operation efficiency of the CFB boiler. It is common in a large CFB boiler to adopt several cyclones in parallel arrangement to the furnace to separate dust from the gas phase. The performance of a cyclone separator has been studied by measurement of the solids distribution in a cross-section in the inlet of cyclone separator.For the cold model of a600MW supercritical CFB boiler, a rectangular electrical capacitance tomography (ECT) sensor has been designed and used to measure the solids distribution in a cross-section in the inlet of cyclone separator. The experimental studies on the arrangement of six cyclones were conducted with different superficial velocities and bed inventories.For image reconstruction, sensitivity maps have been calculated using a simulation package, Maxwell from Ansoft. Static test results are analysed in terms of standard deviation and image error. The optimized operation parameters (Vp-p and Frequency) for the rectangular ECT sensor based on AC-ECT system are given.The cold CFB model scaled down from a600MW supercritical CFB boiler was built in the Institute of Engineering Thermo physics, Chinese Academy of Science. Axisymmetric and centrosymmetric arrangement of six cyclones are investigated in the research. Cold experiment results show that the solids distribution of the cold model with axisymmetrically or centrosymmetrically arrangement of cyclones can be measured in different superficial velocities and bed inventories. For the above two kinds of the arrangement, the solid volume concentration in the six cyclones are different, In terms of uniform of gas and solid mass flow distribution, it is better in centrosymmetrically arrangement than axisymmetrically arrangement.