Temperature control of a batch reactor by the refluxing reaction technique with action on the pressure

In the fine chemical industry the batch or fed-batch reactor functions as the heart of the transformation process. Due to the complexity of chemical synthesis, control of these reactors remains a problem of temperature control commonly performed indirectly via the jacket of the reactor. This work presents a new strategy we have developed to control highly exothermic reactions. This lies on thermal control through pressure derived from the "refuxing technique" commonly used in inudstry. It takes advantage of the fast dynamics of the pressure-temperature dependence at the boiling point. The pressure that should be applied to the reactor to track a set-point temperature is computed via an on-line identified vapor pressure law. This technique has been applied to pharmaceutical industry synthesis reaction. Experimental results obained in a pilot plant show the relevance of this technique particularly in terms of productivity increase and minimisation of environmental impacts.