Mass flow measurement of pneumatically conveyed solids using electrical capacitance tomography

This paper describes a measurement system for mass flow measurement in a pneumatic pipeline. The system mainly consists of a volumetric concentration sensor and a velocity sensor. The concentration sensor is an electrical capacitance sensor which has eight electrodes; the velocity sensor is based on cross-correlating two signals derived from a pair of capacitance sensors. A cyclone is employed in this system where the sensors are placed in order to compensate the inhomogeneity of the sensor sensitivity. Experimental results obtained on a pneumatic conveyer circulating coal ash demonstrate that this system is capable of detecting various velocity profiles and solids distributions and providing an absolute mass flow rate of solids within a good agreement with the reference reading from load cells.