The Gas-Solid Phase Coupleing Simulation And Analysis On The Catalyst Distributor Of The Catalytic Particles

With the rapid development of fluid catalytic cracking, the catalyst distributor of FCC (fluid catalytic cracking) is becoming more and more important for improving the quality of catalyst particles and distributing the particles uniformly. The technological level of FCC catalyst distributor has an effect on Catalytic cracking process.In order to improve the catalyst distributor property and enhance the catalytic particle fluidized effect, both numerical method and analytical method are adopted to analyze gas-solid two-phase flow in catalyst distributor. The CFD (computational fluid dynamics) method and DEM (discrete element method) method are coupled to simulate the motion of catalytic particle. The numerical method is applied to analyze the relation between the fluidized ring structure parameter and fluidization distribution effect. The main work and result of research are list as follows:1. The CFD (computational fluid dynamics) method and DEM (discrete element method) method are coupled to simulate the catalytic flow in catalyst distributor. Both the Eulerian method (method of material particles) and Lagrangian method (spatial description) are combined to solve the problem. The gas-solid coupling method use two-way coupling. Consider the influence of gas phase to solid phase, and take the solid phase into account when compute the gas phase, the gas-solid two phase are solved continuously and alternately. Researching the regularities of distribution of press、 velocity and drag force, the research show that the velocity vector roll up in the middle of catalyst distributor and circulate at the bottom of the catalyst distributor.2. Simulate the movements of catalytic particles in catalyst distributor, research the flow structure in catalyst distributor and analyze the affection between fluidized result and different velocity come from fluidized ring. The research show that when the velocity between30m/s and40m/s the fluidized effect is best and do not need much gas to some extent. It is the optimal range. The diameters of catalytic particles also have an influence on the fluidized effect. The particle have smaller size will be fluidized more easily, and follow the fluidized gas more easily than particles whose have greater size.3. Adopt a method of numerical simulation and theoretical analysis, analysis the effect between size of hole in nozzle of fluidized ring and the fluidized ability. The result show that when Pk is a constant value, the difference parameter with λ have litter influence in particle fluidization coefficient P. when the intensity Pk∈(.0288,0.4) the catalyst distributor can run good.