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摘要
In this work, the coupled model based on an iterative approach was developed to describe the flow behavior and catalytic hydrogenation of dimethyl oxalate (DMO) in a fluidized-bed reactor (FBR). First, a single-particle model (SPM) and a computational fluid dynamics (CFD) model were constructed, respectively. A set of hyperbola-like kinetics equations were included in the SPM. Subsequently, we assumed that all catalyst particles inside each small computational cell for the CFD model experience the same external conditions, which ensures the effective coupling of the two models above. The assumption and the coupled model have been validated by evaluating the above assumption and comparing with the experimental data, respectively. Based on the validated model, the predictions of the two classical diffusion equations (i.e., the Wilke-Bosanquet diffusion equation and the Fick or Wilke diffusion equation) are compared. In addition, the main flow field and reaction parameters in the FBR were investigated numerically. The results indicated that the intrapartice transfer resistance rises with the increase of the particle size, while it is not obvious for the selected studied system. The results also indicated that all of the species mass fraction distributions become more even as the catalyst size becomes smaller and the different diffusion models have little influence on simulation results. The simulated results here also demonstrated that one is capable of investigating reactor behavior at relatively low computational cost by using the proposed multiscale model.
