A dual modality tomography system for particle concentration and charge distribution measurement in dense-phase pneumatic conveyor of pulverized coal

Process tomography (PT) has been widely investigated and developed to measure the cross-sectional distribution of multiphase flow parameters based on different sensing techniques in the past decades. Electrical capacitance tomography (ECT) is a relatively mature method for detecting solid particle concentration while electrostatic tomography(EST) is a new technique to measure the charge distribution carried by particles. In this paper, ECT and EST are combined to measure the particle concentration and charge distribution over the cross-section of a horizontal pipeline with the inner diameter of 10 mm in a dense-phase pneumatic conveying system of pulverized coal under high pressure. The pulverized coal particles with three different sizes are conveyed by nitrogen and carbon dioxide (CO2) carriers in the experiments. The particle concentration and charge distribution, along with the relationship between them are presented and analyzed.