关键词: 下行床, 气固分离器, 相位多普勒颗粒分析仪(PDPA)

Abstract: The particle flow patterns in a gas-solid separator for cocurrent downflow reactors have been studied with a phase Doppler particle analyzer (PDPA), which allows the measurement of particle size and velocity simultaneously. Volumetric flux, particle size distribution and particle velocity vectors are obtained. It is found that the internal components including the rectangular nozzle, circular arc camber and baffles play important roles in the gas-solid separation process. Particles are separated from gas phase due to the gas-solid inertia difference and the collision between the particles and the internal components. Although volumetric flux has a wide distribution in the cross direction, particles are mainly concentrated near the camber surface. Due to turbulent dispersion and drag force in the cross direction, small particles gradually move away from the cambered surface, leading to double-peak distributions of particle size, which influences the collection efficiency of particles. By reducing nozzle width, separation efficiency can be improved.

Key words: downflow, gas-solid separator, the phase Doppler particle analyzer(PDPA)