Residence Time Distribution and Flow Characteristic in a Multistage Stirred Reactor

Continuously operated multistage stirred reactors are widely applied in the chemical industry. Understanding the flow and residence time distribution is vital in the design and optimization of such reactor. In the present work, the fluid flow field and residence time distribution in the multistage stirred reactor equipped with Rushton turbines were investigated numerically. After grid independence and the time sensitivity test and validation with the literature, the effect of several dimensionless terms, including the flow and impeller Reynolds numbers and normalized opening size on the horizontal plate, on the fluid average residence time and residence time distribution was quantitatively evaluated. Thus, the number of equivalent reactors can be varied accordingly by adjusting the flow Reynolds number, the impeller Reynolds number, and the opening between adjacent chambers. Finally, a correlation of the number of equivalent reactors is proposed, which can be used to predict the number of equivalent reactors under various operating conditions.