Isothermal multiplicities

A word of caution is necessary here. Isothermal multiplicity that is the result of nonmonotonic kinetics occurs only when the nonmonotonic kinetic dependence of the rate of reaction upon species concentration is sharp enough. For flat nonmonotonic behavior, multiplicity can occur only for bulk-phase concentrations which are too high to have much practical relevance. 

Oh, Se H., Hegedus, L. L., Baron, K. and Cavendish, J. C., "Carbon Monoxide Oxidation in An Integral Reactor. Transient Response to Concentration Pulses in the Regime of Isothermal Multiplicities" Proc. ISCRE5 ACS Symposium Series 65,... 

It is clear that the reactor designer would need to consider this isothermal multiplicity in selecting the desired reactor operating conditions. 

Figure 7- Isothermal multiplicity for the emulsion polymerization of methyl methacrylate in a CSTR (20h). S = 0.03...

Adsorption of more than one species and complex electrocatalytic surface reactions [Eqs. (10) and (16)] may result in nonunique steady-state operation and in current or potential oscillations (31, 78, 417). We examined recently conditions for isothermal multiple steady states at planar, and porous, flow-by or flow-through electrocatalysts (418). 

D Yu Murzin, T Salmi. Isothermal multiplicity in catalytic surface reactions with coverage dependent parameters case of polyatomic species. Chem. Eng. Sci. 51 55-62, 1996. 

More complex patterns of behavior can be found for finite transport resistances inside the porous catalyst [74]. Here, kinetic instabilities occur on two different length scales. On a first, macroscopic scale, multiplicity is induced by ignition and extinction of every single reactive column tray. On a second, microscopic scale, multiplicity comes from isothermal multiplicity of the single catalyst pellet, which is due to the finite transport resistance inside the catalyst. 

The Langmuir isotherm is thermodynamically correct for single conponent systems. It has also been used as the basis for a variety of other isotherms such as the BET isotherm (multiple layers of adsorbate), the Langmuir-Freundlich isotherm, and the linear-Langmuir isotherm (add a linear isotherm and a Langmuir isotherm Eq. (18z6c) with different values of a). The Langmuir isotherm is also commonly extended to the adsorption of multiconponent mixtures. For exanple, for the simultaneous adsorption of conponents A... 

Carbon Monoxide Oxidation in an Int ral Reactor Transient Response to Concentration Pulses in the R ime of Isothermal Multiplicities... 

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