Mass and heat transfer behavior of a new heterogeneous stirred tank reactor with serpentine tube baffles

[Display omitted] •Stirred tank reactor with a serpentine tube baffle is a promising reactor.•Mass transfer coefficient increases with rotational speed for both types of impellers.•Enhancement of mass transfer rate using radial flow turbine is better than axial type.•Mass transfer coefficient is more sensitive to Sc with radial flow turbine than axial.•Overall empirical correlations were developed under different conditions. Rates of mass transfer at a serpentine tube baffle in a cylindrical stirred tank reactor were measured by the diffusion controlled dissolution of copper in acidified dichromate. The serpentine tube baffle has the potential to act as a catalyst support and a cooler. As such stirred tank reactors with serpentine tube baffles are suitable for conducting exothermic diffusion controlled liquid–solid catalytic reactions which need rapid temperature control e.g. immobilized enzyme catalyzed biochemical reactions. Variables studied were impeller rotation speed, impeller geometry, physical properties of the solution, pitch (copper tube separation within the serpentine tube) and diameter of the serpentine tube baffle. Mass transfer data for axial and radial flow impeller were correlated by dimensionless mass transfer equations which can be used in scaling up the present reactor as well as calculating the rate of heat transfer (by analogy) across the serpentine tube baffle cooler. The advantages of the present reactor compared to other heterogeneous stirred tank reactor such as the slurry reactor were pointed out.