Although gas-solid fluidized beds have been widely used in various processes

the development of reliable and non-intrusive measurement techniques for solid-gas two-phase flows in fluidized beds is still attracting considerable attention. Due to its advantages of simple construction and high temporal resolution

electrical capacitance tomography (ECT) has been widely applied in multi-phase flow measurements. This paper reviews the application of ECT in gas-solid fluidized bed measurement

including the measurement of solids distribution

flow regime transition

solids flow velocity

and water content in fluidized bed dryers. The challenges of ECT in gas-solid fluidized bed measurement are also discussed.