Ideal Continuous Plug-Flow Reactor PFR

The plug-flow reactor is the third and last of the so-called ideal reactors. It is frequently represented as a tubular reactor, as shown below. 

The ideal plug-flow reactor has two defining characteristics  

There is no mixing in the direction of flow. Therefore, the concentrations of the reactants decrease in the direction of flow, from the reactor inlet to the reactor outlet In addition, the temperature may vary in the direction of flow, depending on the magnitude of the heat of reaction, and on what, if any, heat transfer takes place through the walls of the reactor. Because of the variation of concentration, and possibly temperature, the reaction rate, ru varies in the direction of flow  

There is no variation of temperature or concentration normal to the direction of flow. For a tubular reactor, this means that there is no radial or angular variation of temperature or of any species concentration at a given axial position z. As a consequence, the reaction rate r,-does not vary normal to the direction of flow, at any cross section in the direction of flow. 

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