CO oxidation on Pt: Model discrimination using experimental bifurcation behavior

Abstract

An experimental determination of the steady state behavior for the supported platinum catalyzed oxidation of carbon monoxide in a recycle reactor was performed. Steady state multiplicity was observed. The effects of the size of catalyst charge, feed flow rate, feed composition, and reactor temperature on the location of the boundaries of the steady state multiplicity region were determined. The sensitivity of these bifurcation points to variations in reactor parameters was used to discriminate among five reaction mechanisms. Only an elementary step model incorporating carbon monoxide self-exclusion from the catalyst surface could quantitatively describe all observed steady state data. An explicit rate function based on this model is presented.

In‐situ Positron Emission of CO Oxidation

“…The CO adsorption capacity found is 2 x 10-5 mol CO/m 2 Pt. Values used in simulation experiments (Table 2b) correspond well with literature values (31)(32)(33). The relatively high sticking coefficient of O 2 on the platinum surface is due to the promoting effect of the ceria present at the catalyst surface.…”

NO Reduction by CO over a Pt/Al2O3 Catalyst: Reaction Kinetics and Experimental Bifurcation Behavior

“…It is assumed that the adsorbed CO molecule excludes other CO molecules from an area equivalent to N CO Pt atoms, where N CO is slightly greater than unity. The rate of CO adsorption with the CO self-exclusion effect is given by which has been derived previously by Graham and Lynch (1987).…”

State Estimation in a Catalytic Reactor via a Constructive Approach

“…Let us consider the laboratory continuous catalytic reactor shown in Figure 1 where carbon monoxide is converted into carbon dioxide via a complex combustion exothermic reaction that is carried out on a Pt-alumina-support catalyst (Graham and Lynch, 1987), with heat being removed by means of a heating-cooling system, according to the following lumped kinetics and heat model (Baratti et al, 1993): In dimensionless units (c r = 1.052 mol/m 3 is the reference concentration and T r = 463 K is the reference temperature) x 1 is the reactant (CO) concentration, x 2 is the reactor temperature, d 1 is the feed concentration, d 2 is the feed temperature, d 3 is the wall temperature, z is CO mole fraction, y is the temperature measurement, and p = [1.21x10 6 s -1 , 2.993, 16.72, 280.0 KJ/mol, 59.2 KJ/(m 3 K), 0.812 KJ/(m 3 K), 2.38x10 -5 KJ/(s K), 3.85x10 -2 s -1 ] T is the model parameter vector. (θ, κ, δ) were determined from mass and heat step responses without reaction, and (β, γ, σ) were determined from isothermal steady-state experiments at various temperatures.…”