Steady-State Rate-Based Simulation of Packed Reactive Distillation:  Spatial Discretization

This paper investigates issues related to the numerical simulation of rate-based models for catalytic distillation processes. Special emphasis is placed on spatial discretization in the solution of steady-state models describing packed reactive distillation columns. A general rate-based model for packed reactive distillation is briefly presented, along with its underlying assumptions. This mathematical model is then discretized along its spatial dimensions using different finite-difference schemes. In this paper, steady-state simulations are considered to assess various properties of the different discretization methods. Using a tert -amyl methyl ether (TAME) packed reactive distillation as a case study, we show that a cell-based approach, similarly to a first-order finite-difference approximation, is inefficient in converging to the solution of the mathematical model. To address this problem, a higher-order discretization scheme is used, and its advantages are illustrated. This latter method is of interest for reducing computation time and might permit model-based control strategies, which require steady-state and dynamic models of tractable sizes.