Non-permselective CMR

For an instantaneous reaction, a reaction plane is established for slower reactions a reaction zone exists which can be kept completely within the membrane by the right balance of reaction rate and permeability. Keeping reactants completely segregated by this device is possible so that reactant A does not break through to the tube side and reactant B does not break through to the shell side. It is also possible to control the product P to diffuse out of the membrane on one side only, in this case the tube side, which greatly simplifies the downstream separation task. 

This type of membrane reactor ensures that the reactants meet in a strict stoichiometric ratio, since at steady-state the permeation flux of a reactant is equal to its rate of consumption in the reaction. A change in reactant flow rates acts to shift the zone to satisfy stoichiometry. It has been investigated experimen- 

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Non-permselective CMR - In this type of reactor (sometimes called a CNMR), the membrane plays no separative role, but simply provides a location for the establishment of a reaction zone. This is shown schematically in Figure 5 for the reaction A + B P. One reactant (B) is fed on the tube side of the membrane, and the other reactant (A) is fed on the shell side. The partial pressure gradients set up cause them to permeate toward each other inside the membrane, where they react. 

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