A Reduced-Order Model of a Fixed-Bed Reactor based on Novel Application of the Taylor-Dispersion Approximation

Taylor dispersion in a fixed bed reactor results from heat exchange between the flowing reactant stream and the fixed thermal capacitances of the catalyst particles and reactor wall. The Taylor approximation transforms the hyperbolic partial differential equations representing deviations of the energy balance from steady-state into a single parabolic partial differential equation encompassing convection and diffusion. The hybrid Taylor diffusion model developed here incorporates spatially varying heat generation by reaction into the parabolic partial differential equation and couples it to a material balance on the fluid. A third or fourth order spatial discretization of this model provides a good approximation of the frequency response, and was used for online control and optimization.