Solids Flux, Velocity and Local Solid Fraction Measurements in a CFB Riser

In this investigation a fiber-optic probe and an extraction solids probe are used to measure particle velocities and solids flux values. These are subsequently used to determine the local solids fractions as a function of radial position in a cold flow circulating fluidized bed (CFCFB) in operation at the National Energy Technology Laboratory (NETL). Measurements were taken under several separate operating conditions ranging from dilute up-flow to core-annular flow to fast fluidization using nominal 800 micron cork particles. The solids properties and test operating conditions were chosen particularly to provide dynamic similitude between the test data and the operation of a high temperature, high pressure gasifier. The data from these conditions is different in many ways from the data developed using more conventional solids (glass, FCC, and sand) at atmospheric conditions. In this paper, the data from the middle of the riser corresponding to a height of nominally 8 m is presented. Average solids fractions are compared to the apparent values based upon the pressure drop and the near wall measurements are compared to LDV generated solids fraction values, showing good agreement with both. Also, the radial profiles tended to be relatively flat with a sharp rise at the wall