Experimental Study On Circulating Character Of Particle In Liquid-Solid Criculating Fluidized Bed

The aim to study the hydrodynamic characteristic of particle is to offer a reference to the design of external circulating fluidized bed. In this paper, it has been studied that the circulating characteristic of solid particles in liquid-solid external circulating fluidized bed which made use of nozzle as the particle circulating equipment. Some effects were tested for diameter of nozzle, position of nozzle, particle diameter, particle diameter, liquid flow, particle amount and the liquid viscosity on minimum circulated velocity, pressure drop, solids holdup, suction pressure and solids circulating flux. The formulas of minimum circulating velocity, pressure drop and the solids holdup, suction pressure and solids circulating flux were put forward.As a result, the diameter of nozzle is the critical factor in the particle circulating, and when the diameter of nozzle is 0.375, the synthesis effect is the most good. When the circulating fluidized bed was operated in the same capacity, the nozzle of which diameter is 0.375 could get the max solids circulating flux and solids holdup in the pipe of heat-exchang. When nozzle was installed in the position that was adjacent to the edge of fallen pipe, the length of suction pressure is the longest and it is the most favorite to the solids circulation. When the liquid viscosity increased, the suction pressure increased, the minimum circulating velocity decreased, the solids holdup increased and the solids circulating flux increased. When the diameter of particle increased, the minimum circulating fluidized velocity increased. When particle amount increased, the solids holdup and the solids circulating flux increased.