Optimal CO clean-up reactors design. Modeling and optimization aspects

FRANCESCONI JAVIER; OLIVA DIEGO; MUSSATI MIGUEL; AGUIRRE PIO

Lyon

Congreso; 18th European Symposium on Computer Aided Process Engineering (ESCAPE-18);; 2008

IFP Institute Francais de Petrole

This work applies model-based optimization techniques for designing the CO clean-up packed bed reactors involved in an ethanol processor for hydrogen production applied to PEM fuel cells. The reactors considered are the high-stage and low-stage water-gas-shift units, followed by a CO-PrOx unit. The reactors are modeled considering a 1D- heterogeneous model of a catalytic fixed bed.  An optimization problem was formulated to determine the operating and design variables that minimize the total system volume. Each unit consists of a reactive bed, insulating material, reactor tube and heads. The model computes the exigencies required for the constructive materials, such as maximum and minimum operation temperature for catalyst and insulating materials. The optimization problem determines the optimal value of the reactor length and diameter, catalyst particle diameter and insulation thickness. Two alternative optimization approaches are compared: (a) single unit optimization of each reactor involved, and (b) whole-system (simultaneous) optimization. The latter allowed achieving an optimal design with a total system volume reduction about 20% compared to the single units optimization. The resulting PDAEs system is implemented and solved using gPROMS.