Electrical Capacitance Tomography in dense-phase pneumatic conveying of pulverized coal under high pressure

The electrical capacitance tomography (ECT) system is applied to identify the flow regime of gas-solid flows in horizontal pipeline with 10 mm inner-diameter in a pulverized coal dense-phase pneumatic conveying experimental setup at the pressure up to 4.0 MPa and the solid-gas ratio up to 11.73 kg/kg. 8-electrode thick-pipeline and small-diameter ECT sensor applied in high pressure is fabricated, and the pipeline thickness is 5 mm. For the purpose of analyzing the effect of pipeline thickness on ECT sensor, radius-electrode ratio is defined as the ratio of inner and outer radius of pipeline. The rules of 8-electrode sensor parameters such as capacitance, capacitance change, and change rate of capacitance and sensitivity map are discussed by ANSYS and Matlab, which are combined to simulate sensor characteristic. With the increase of radius-electrode ratio, the effect of pipeline thickness on capacitances of four typical inter-electrode pairs is much different. LBP algorithm is adopted to reconstruct the images of stratified flow, core flow and annular flow with different radius-electrode ratios. Simulation results show that image error under high radius-electrode ratio is small, and the image reconstructed from stratified flow is better than the ones from core flow and annular flow. Finally, the experimental result of 8-electrode ECT with thick pipeline sensor, which is used on the pulverized coal dense-phase pneumatic conveying experimental setup, is given.