Temperature control in reactors with gradients

For reaching a high degree of conversion it may be necessary to employ a reactor with axial concentration gradients, such as described in section 7.2.2. Yet it may be desirable to operate the reactor under isothermal conditions. For exothermic reactions, this can be achieved in two ways  

An interesting example of a cooled tubular reactor is the falling film reactor (or wetted wall column), that was described in section 4,63.1. en the film is sufficiently thin and the evolution of heat is not too excessive, a very uniform temperature can be obtained. 

An interesting example of the second type is the gas-fluidized bed. When the reactor is equipped with immersed heat cooling tubes, a very effective temperature control is possible (Xavier and Davidson, 1985). 

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