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.