Experimental Study On Cold Simulation Of Gas-Solids Two Phase Flow In FCC Reactors

Two experimental installations of cold simulation are built. One is a small FCC reactor of confined fluidized bed, the other is a FCC riser made up of two sections with different diameters, which has two assistant gas side-inlets at the bottom. In the experiment of small FCC reactor of confined fluidized bed, the pressure fall off curve of the bed was surveyed. The results show that the gas-solids two phase flow of the bed is poly-grouping flow behavior with slugging and channeling, and there is a clear interface which divides the bed into two phases, dense phase and thin phase. In the experiment of new FCC riser, particle concentrations and particle velocities on 8 axial levels were systematically measured with the superficial gas velocity ranging from 2.08m/s to 3.06m/s and the solids circulation rate from 10kg/(m2s) to 90kg/(m2s). The results show that the section with bigger diameter at the bottom increases the local particle concentrations. With increasing Gs or decreasing Ug,the local particle concentrations in the whole riser increase, resulting in that the axial profiles of the cross-sectional averaged particle concentrations are exponential. Local particle velocities in the bottom acceleration region are lower but more evenly distributed in the radial direction, improving the back-fall and back-mixing of particles. With increasing Ug and increasing Gs, the axial profiles of the cross-sectional averaged particle velocities in the whole riser increase.