The animation shows the flow of gas through a generic fast fluidised bed riser. Particulate material is injected through a side port and mixes with the upward-flowing gas stream.
If the animation does not load or is of poor quality, try running this compiled Smacker file: f4.exe (0.6MB).
Note that this is an executable file, and should be suitable for all PCs running Win95 or later. For more information about Smacker and its compiled executables, please follow this link.