CFD Modelling of Heat Transfer and Chemical Reactions in Jacketed Stirred Tank Reactors

Organic synthesis reaction processes are commonly performed in the fine chemicals and pharmaceutical industries in batch jacketed stirred tank reactors (STRs) of a range of scale sizes – from laboratory to full manufacturing scales. Chemical synthesis of fine chemicals and pharmaceuticals is often complex involving multiple reactions and conversion/selectivity are critically dependent on the mixing and heat transfer characteristics of the reactor. Heat transfer between the jacket fluid and the reactor contents plays an important role in controlling the temperature of the process liquid. This is of paramount importance, for example, in preventing thermal runaway reactions.

In STRs, inhomogeneous and transient hydrodynamic conditions prevail resulting in imperfect mixing and non-uniform temperature distribution. Spatial and temporal variations in reaction conditions can generate undesired by-products and reduce yield. Therefore, accurate predictions of reactor temperature distributions as a function of the jacket inlet temperature and mixing intensity are required for an improved design of the synthesis route and precise control of the process.

This PhD project builds on our previous computational fluid dynamics (CFD) study of conjugate heat transfer in a pilot-scale STR. The main objectives of this project is to further develop and validate the conjugate heat transfer model and develop a reaction process model for industrially important reaction systems for integration with the CFD-heat transfer model.

Experiments will be carried out in laboratory scale reactors (0.5 – 5 L) for collection of date for model validation. This comprehensive model will be an extremely powerful tool in predicting accurately reaction product distributions and facilitating the design of safe reactors, determining a safe operational envelope via exploring process conditions leading to runaways, and in conducting computational experiments to minimise the number of real experiments in large scale sizes which are inherently unsafe and time consuming.