Critical phenomena of an exothermic reaction proceeding on a partially wetted porous catalyst grain

A mathematical model has been developed to analyze gas–liquid hydrogenation reactions of hydrocarbons accompanied by liquid evaporation and chemical transformation in liquid and vapor phases on a porous catalyst grain. Critical phenomena caused by the joint action of the exothermic catalytic reaction, phase transitions, multicomponent diffusion, and capillary penetration (percolation) are numerically studied. The domains of multiplicity of stationary modes are determined, depending on wetting of the external surface of the catalyst grain, activity of the catalyst reaction heat, evaporation heat, and parameters characterizing grain impregnation by the liquid. The adequacy of the results obtained by the mathematical model was validated by experimental data.