The Study About Gas-Solid Two Phase Flow In Catalyst Distribute And Device Optimization

In the ctalytic cracking of oil industry, the catalyst particles impacted the pipe continuously in a high speed. The device may be leaded to be failure, and it would cause mass loss of catalyst particles which would reduce the efficiency of catalytic cracking. So, it is necessary to study the movement characteristics of particles in the device to provide a theoretical basis and data support for the oil refining enterprises.By studying the movement characteristics of gas-solid flow in the catalyst distributor, with coupling computational fluid dynamics method and the discrete element method, using DEM method to simulate catalyst particles of discrete phase and CFD method to simulate the flow of continuous phase, useing compressible LES turbulence model to analyze the movement of particles in the catalyst distributor. The collision times between particles and particle, and the impact velocity, the collision times between particles and wall, and impact velocity, and the effect of catalyst particles fluidized were counted. The different parameters of the structure were studied to analyze impact behavior and fluidization effects of particles. The finite element method was used to simulate the mass loss of each impact. Minimum mass loss was selected as the optimal structure.The main research and achievements were as follows:1. Most of the impact was located in the outlet of regeneration standpipe and inlet of the distribution arm to catalyst particles. In outlet of regeneration standpipe, particles decelerate rapidly in the drag force of the fluidized air, while the particles in the standpipe were continued gathered to port, making a large number of particles concentration in this region, so the impact between the particles and the particles significantly increased. In the inlet of distribution arm, the impact between catalyst particles and the wall increases because of the changing of the path. On the other hand, the bouncing ball go back to the gas field may impact with other balls.2. The angle of the fluidized ring and the angle of the distribution arm were changed to secelt the optimize structure.3. By finite element method to simulate of the impact between wall and particles, impact between particle and particle. The numerical results indicate that in the structure of α=45,β=15was the optimize structure.