喷嘴对液固外循环流化床内颗粒循环特性的影响

Effect of Nozzle on Solid Particle Circulating Characteristics in Liquid-solid Exterior Circulating Fluidized Bed

液固外循环流化床换热器可以用来蒸发浓缩单基药提取硝化棉的提取液。设计了实现液固外循环流化床内颗粒正常循环的关键部件喷嘴,构建了以喷嘴作颗粒循环装置的液固外循环流化床换热器,研究了喷嘴的结构参数及操作参数对起始循环流体流量、全床压降、负压和最大颗粒循环流量等的影响。结果表明,喷嘴的口径比及安装位置对提高颗粒循环效果均存在一个最佳值,为外循环流化床换热器的设计计算提供了依据。

Liquid solid exterior circulating fluidized bed heat exchanger can be used to evaporate and concentrate the extract of single-base powder when withdrawing nitrocellulose from it. The nozzle as a critical part in the exterior circulating fluidized bed was designed to control the solid circulation. The liquid solid exterior circulating fluidized bed heat exchanger （LSECFBE）, which made use of nozzle as the particle circulating device, was established. The effects of structure parameter of nozzle and operating parameter on the onset circulating flux, pressure drop of fluidized bed, suction pressure and maximum solid circulating flux were studied. On the basis of analysis, an optimal nozzle diameter ratio and nozzle position which made the solid circulating effectiveness perfect were obtained. It provides some theoretical information for the optimal design of the LSECFBE.