ABSTRACT
The basic difference between a fluidized combustor or gasifier and a pulverized or stoker-fired
boiler is in the hydrodynamics of the gas-solid motion in their furnaces or reactors. Interestingly,
most of their environmental and operating characteristics are a direct result of the hydrodynamics of
gas-solid interaction. For this reason, the performance of a fluidized bed boiler or gasifier drops
significantly when the operation of its furnace deviates from the designed fluidization regime. Thus,
a good understanding of the gas-solid motion in the furnace or reactor of a fluidized bed unit is very
important. The present chapter presents a brief summary of the hydrodynamics of bubbling and
circulating fluidized beds.
