The design and analysis of a multiparticle fluid-solid reaction system is discussed. The types of contacting devices discussed are fixed beds, moving beds, fluidized beds, and continuously stirred tank reactors. The analysis, however, can be extended to other multiparticle systems. It is shown how the analysis of the reaction of individual solid particles discussed in the previous parts of this review forms the basis for analyzing a multiparticle system combined with the reactor configuration, fluid flow, and the rate of supply of the fluid reactant.
Also in this article, a powerful mathematical technique called the "population balance model" for describing a reaction of a multisized particle system is introduced. It is believed that this recently developed technique will find many applications in the design and analysis of various chemical and extractive metallurgical processes involving particulate assemblages.