To operate a fluidized bed reactor most efficiently, one needs to have a good understanding of the hydrodynamics inside the bed as well as a good understanding of the mixing and segregation patterns that occur if the bed is multi-component. Many studies have been carried out in an attempt to address these issues, and the findings have contributed to make a variety of processes more efficient. However, since fluidized beds are an opaque medium, it remains difficult to experimentally investigate hydrodynamics and mixing/segregation patterns without significant trade-offs. This study discusses experimental efforts aimed at understanding mixing and segregation in multi-component cold-flow fluidized bed reactors.

A non-invasive measurement technique called X-ray computed tomography (CT) has been used to experimentally investigate mixing and segregation in 3D fluidized beds. New analysis tools for quantifying the bed "mixedness" and level of segregation in a fluidized bed were developed. The method and analysis techniques are explained in detail. The fluidization gas flow rate, particle size, particle density, mixture ratio, fluidized bed size, and the humidity of the gas stream can have a significant effect on the level of segregation of the fluidized bed. The newly developed analysis tools have been proven to represent the varying levels of segregation sufficiently and have been found to be superior to previous introduced measures.