-5- - Conversion of Solids in Rotary Reactors

Abstract

This chapter discusses the conversion process of solids in rotary reactors. It reveals that when the gaseous reactant diffuses within the rotating layer of solids, the overall rate of solid conversion is found to be extremely slow on a practical scale. Injecting the gaseous reactant directly into the rotating layer of solids enhances the rate of conversion appreciably. On a rotary reactor, where rotating tube tuyeres are positioned, gaseous reactant percolates through the rotating layer of bulk solids and contacts with solids. When fine solids are charged, they are apt to partially fluidize and the surface of the rotating bulk solids is flattened. Gaseous reactant percolates through the rotating layer of solids, achieving cross-flow contact. This is needed to send the gaseous reactant selectively to tubes that are just immersed in the rotating layer of solids. The design and development of a satisfactory rotary manifold, which can completely prevent leakage of reactant gas, are of the utmost importance. In the case of endothermic reaction, the small fraction of solids does not appreciably enhance the total rate of conversion. When small solids fall in a reactor, where an exothermic reaction takes place between gas and solids, the temperature of the solids rises rapidly to its stable value. Once the above phenomenon occurs in the rotary reactor, the overall rate of conversion increases enormously.