Simplified Model for Reactive Flow

This complete model is valid for all of the components but, actually, the gas-liquid mass transfer (JVl, ) term is nonzero for hydrogen only. The PDE model can be further simplified by taking into account the fact that conversion is minimal during one cycle through the channel, and the concentration profile in the channel can be assumed to be almost linear, that is, the differential reactor concept can be applied. The entire model can now be expressed by the average (c ) and the outlet concentration (co)  

The exact formulations of the fluxes N ) depend on the particular model being used for mass transfer principally, the whole scope is feasible, from Pick s law to the complete set of Stefan-Maxwell equations. Since the only component of importance for the gas-liquid mass transfer is hydrogen, which has limited solubility in the liquid phase, the simple two-film model along with Pick s law was used, yielding the flux expression 

For the liquid-solid interface, a local quasi-steady-state mass balance takes the form 

In case the liquid-solid mass transfer is rapid, the bulk and surface concentrations coincide, and the rate expression is directly inserted into the balance equation, which becomes 

The surroundings of the monolith are described by the concept of complete backmixing, which leads to the following overall mass balance for the components in the surrounding liquid phase  

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