Basic fluidization considerations

The gas distributor has a considerable effect on the proper operation of the fluidized bed. Basically, there are two types (Perry and Green, 1999) (a) for use when the inlet gas contains solids and (b) for use when the inlet gas is free of solids. In the latter case, the distributor is designed to prevent the backflow of solids during normal operation, and in many cases, it is designed to prevent backflow during shutdown. To provide distribution, it is necessary to restrict the gas or the gas and solids flow so that the pressure drops across the restriction amount of 0.5 to 20 kPa. 

In applications and in basic studies of fluidization, it is not only desirable but often necessary to give full consideration to the multitude of operating forces between fluid and particles on the one hand, and between particles and particles on the other. 

The fast fluidized bed reactor can offer several considerable advantages over alternative reactors for many catalytic and non-catalytic reactions, especially for very fast exothermic/endothermic reactions. With the mushrooming of high activity catalysts and the ever increasing pressure for energy conservation, environmental controls, etc., FFB can play more and more important roles in these areas. More potential commercial applications of FFB in the near future include hydrocarbon oxidations, ammoxidation, gasoline and olefines production by concurrent downflow FFB and basic operation for organic chemical productions. 

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