Knowledge of the heat transfer coefficients of reactors can provide important information relating to the thermodynamics of a reaction and estimation of the overall reaction power and enthalpy. The new Technical Bulletin details how these heat transfer coefficients have been calculated for Lara reactors and includes original experimental data and suggested reference reading material.
The Lara is a flexible, modular CLR unit which enables easy connection and interchange of vessels, heat transfer equipment and measurement devices. All devices are linked and controlled by software which also allows full data logging. The Lara CLR has a wide range of standard vessel sizes (250 ml to 10 litres), in the described experiments the 1L and 5L vessels were characterised with respect to heat transfer.
In order to investigate heat transfer in aqueous and organic systems, water and methanol were chosen as the 'reaction fluids'. The contents of the vessels were repeatedly heated and cooled at several volumes and impeller speeds. Using the physical parameters (vessel diameter, fluid density, and fluid specific heat) of the reaction the heat transfer coefficients for water and methanol were calculated at several volumes and impellor speeds based on the temperature profile data obtained for the jacket and reactor contents over time.
The reported heat transfer coefficients obtained are useful in calorimetric measurements and can be used to predict the heating and cooling times as well as reaction exotherms when considered with the log mean temperature difference.
