Numerical Investigation of Process Enhancement Using a Bifunctional Catalyst in a Dual Fluidized-Bed Reactor

Abstract

The paper outlines the concept of process intensification and integration, with a particular focus on sorption-enhanced, solid-catalyzed chemical processes. An alternative and attractive solution to a system of parallel fixed-bed apparatuses is evaluated, which utilizes the solids’ circulation in a dual fluidized-bed reactor–regenerator system. This allows for continuous mode operation and greatly simplifies the control procedures. To illustrate some aspects related to the steady-state operation of such a dual system, a simplified mathematical model of two interconnected fluidized beds operating in the bubbling regime was developed. A generic reversible chemical reaction of the overall second-order, catalyzed by bifunctional pellets, integrating catalytic active sites and adsorption sites, was considered as a test case. The model was used to study the effects of the bed hydrodynamics, as well as of the chemical reaction and physical adsorption equilibrium constants. It was shown how the superposition of various chemical, physical and hydrodynamical phenomena affects the performance of the system.