Tracing the motion of a large object in a fluidized bed using electrical capacitance tomography

• A simple method to trace a large object's motion in dense zone of fluidization bed is proposed.
• The method is a combination of tracing concept, image processing techniques and electrical capacitance tomography (ECT).
• Recalibration process is applied to improve ECT measurement's nonlinearity.
• It is verified to be a practical technology in study irregular large object motion in multiphase system.

An innovative method using electrical capacitance tomography (ECT) to trace a large object's motion on an air distributor in a fluidized bed is described here. The method fills the large object to be traced with a high permittivity material, and then a recalibration process is applied to reduce the nonlinearity caused by the large permittivity difference between the tracer particle and other fine particles in the measurement zone. The local dynamic threshold selection method is performed on the reconstructed image to locate the tracer particle's position.Static simulations and dynamic experiments testify that tracer particles with a diameter of one ninth of the measured cross-section and a fluidization velocity v/vcr≤4.2 can be accurately located and traced. Employing this method to trace the motion of a spherical object in a bed shows that the fluidization velocity significantly influences the directional motion of a large, heavy object on an inclined air distributor.

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