(397d) Heat Transfer Characteristics Using Structured Catalyst Support in Packed Bed Reactors

The present work focuses on the thermal performance of structured-catalyst support in a packed-bed reactor by conducting experiment in tandem with CFD modelling. Both liquid (water) and gas (air) are being investigated to ascertain whether thermal conduction or forced convection limits the heat transfer mechanism. The different structured configuration such as diamond, cubic and hexagonal shapes are employed for heat transfer augmentation. The quantitative enhancement in heat transfer from structured support is determined by comparing its effect on heat transfer coefficient with that of the case of both empty tube and pellet medium. In addition, by comparing the aforementioned cases of structure with pellet medium, we will be able to identify whether the heat transfer mechanism is governed by conduction or convection. The temperature gradient near the heating wall is significantly high in case of both liquid and gas, causing low heat transfer coefficient, resulting in poor heat transfer efficiency. To minimize this effect, we utilize the combination of structured support with pellet to enhance the averaged thermal conductivity of the medium. The CFD modelling helps to gain insight into the radial temperature fields along the reactor length, and evolution of velocity profile inside the packed bed which is difficult to measure in the experiments. The CFD simulation investigates the characteristics of bypass flow especially near the heating wall and regions within a unit cell of structured support. By analyzing temperature gradient in the radial direction, an accurate quantitative estimation can be made on the impact of medium’s thermal conductivity on heat transfer augmentation. The CFD simulation with more cases of different geometries and dimensions will be conducted in order to provide adequate data for the optimization analysis, which will be used by the experiments for confirmation of the optimal heat transfer configuration.