A platinum catalytic reactor in an automobile is used to convert carbon monoxide to carbon dioxide in an oxidation reaction of the form 2CO + O2 l 2CO2. Species transfer between the catalytic surface and the exhaust gases may be assumed to occur by diffusion in a film of thickness L = 10 mm.
Consider an exhaust gas that has a pressure of 1.2 bars, a temperature of 500°C, and a CO mole fraction of 0.0012. If the reaction rate constant of the catalyst is k1" = 0.005 m/s and the diffusion coefficient of CO in the mixture is 10-4 m2/s, what is the molar concentration of CO at the catalytic surface? What is the rate of removal of CO per unit area of the catalyst? What is the removal rate if k1" is adjusted to render the process diffusion limited?