| Although standpipes are essential to the operation of circulating fluidized bed systems (CFB), their hydrodynamics are poorly understood, and are often unpredictable in displaying effects such as hysteresis which could be due to forces such as particle-wall shear stress.; In this research the one-dimensional gas-solids mixture momentum balance is applied to the standpipe. Neglecting acceleration effects, the important forces are the gas and solids phase pressure drop, weight of the bed, and the particle-wall shear stress. Gas pressure drop is measured using differential pressure transducers. The weight of the bed is assumed constant. The wall shear stress is measured utilizing instruments developed by WVU and NETL in Morgantown. The solids phase pressure drop is inferred to be the residual portion of the momentum balance.; Estimations of these forces are included for both coke breeze and cork bed materials. An attempt to model shear stress and solids pressure has been made. |
