Measurements of Local Flow Characteristics in a Gas–Liquid–Solid Circulating Fluidized Bed with Immersed Telocentric Photography

Abstract

The gas bubble size, local phase holdup, and other local flow characteristic parameters of the gas–liquid–solid circulating fluidized bed play an important role in the design and operation of this type of reactor. However, due to the limitation of measurement techniques of three-phase fluidization, the local flow characteristics have not been well measured and studied. In recent years, telecentric imaging technology has been applied in other multiphase systems, and a new telecentric probe method has been used to measure the local flow characteristics of a gas–liquid–solid expanded bed. In this work, the measuring method was introduced to measure the local phase holdups and bubble size distributions of the three-phase circulating fluidized bed. Concurrently, the influence of the superficial liquid and gas velocities on the particle circulation rate in the three-phase circulating fluidized bed was studied. The method reliability of gas holdup and bubble size measurements was validated by a conductivity probe method. The results provided basic data of such a reactor for future flow numerical simulations and industrial applications.