Numerical hydrodynamic characterization for the design of a lab-scale jet-loop reactor

Abstract

The jet-loop reactor is a powerful tool for analyzing the kinetics of heterogeneous catalytic reactions due to its high mixing degree. Indeed, the high momentum gas flow injected within the loop induces a large gas recycling flow, minimizing concentration and temperature gradients. The purpose of this numerical study is to optimize the geometric features of the reactor (injection nozzle diameters and length, and outlet pipe diameter) to improve the gas recycle ratio. Its hydrodynamic behavior is predicted by using multi-fluid solver, with an immersed boundary method to model the injector and easily vary its geometry. The effects of the operating parameters such as the injection flowrate, the pressure and the temperature are also assessed. In addition, a residence time distribution analysis allows for the evaluation of the Péclet number as a function of the geometric and operating parameters of the reactor. Then, a zero-dimensional hydrodynamic model, based on a macroscopic momentum balance, is finally developed. After fitting specific terms thanks to separated numerical CFD simulations, it enables a rapid optimization of the reactor design and provides insights into its behavior.