ABSTRACT
Regenerative sorption on porous solids can be used to separate many mixtures into their components, to remove an air pollutant present in very small concentrations, or to store a gas. The key to any regenerative system is finding a simple reaction with a small negative standard free energy change. This chapter summarizes typical rates for some of the solid-gas reactions. In these reactions, structural changes are often important, because diffusion takes place through the pores filled with a fluid, not through the solid phase due to its low diffusivity. The chapter proposes the continuum solid phase mass balances ratio called E in a natural way. The most common model which finds some application in this field is the moving boundary or the shrinking core model. The ratio of the initial rate is meaningful for fluid solid reactions with pore closing, because their rates decrease exponentially with time even for large Thiele moduli.
