Flow Patterns of Pneumatic Conveying of Pulverized Coal in Horizontal Pipes for Pressurized Conditions

Pulverized coal with a mass average diameter of 69 μm and a real density of 1444 kg/m³ was transported at an experimental bench for powder pneumatic conveying at pressurized conditions (up to 0.84 MPaA). Flow patterns of the pipe flow were observed by ECT (Electrical Capacitance Tomography) technologies. Differential pressures in horizontal pipes were measured. The ECT images showed a comprehensive evolvement of flow patterns with decreasing superficial gas velocities, consistent with Geldart´s and Pan´s descriptions. The differential pressures fluctuated in different modes for different gas-solid flow patterns inside the pipe. This paper indicated the differential pressure fluctuation as a useful feature to predict flow patterns at horizontal pipes.