Singular Langmuir-Hinshelwood reaction-diffusion problems. strong absorption under quasi-isothermal conditions

Abstract

The steady state reaction-diffusion problem is considered for a permeable catalytic particle with Langmuir-Hinshelwood kinetics under isothermal and quasi-isothermal conditions. It is known that there may be multiple solutions due to either strong adsorption or external thermal effects; in the first case, an arbitrarily large number of solutions may appear for symmetric pellets in two and three dimensions. An asymptotic analysis provides analytical expressions for the response curve of the particle and for the multiplicity bounds. The approximate results compare quite well with those computed numerically, even in cases in which the gauge functions of the approximation scheme are of the logarithmic type.