负压差立管插板阀调节颗粒质量流率的实验分析

在大型循环流化床装置上,通过改变负压差立管上的插板阀的开度,测定不同颗粒质量流率条件下插板阀上下的流态和脉动压力,以此分析插板阀对下料过程颗粒质量流率的调控机制。实验结果表明,对于立管的下料过程插板阀的开度存在一个临界开度,将插板阀的开度范围划分为非可控制区和可控制区。当插板阀的开度大于临界开度时,处于非可控制区,不能进行颗粒质量流率的调节,此时插板阀上下的流态一致,脉动压力曲线相似;当插板阀的开度小于临界开度时,处于可控制区,可以进行颗粒质量流率的调节,此时插板阀上的流态是移动床,阀下的流态是雨状下落流,上下的脉动压力曲线不同。

Solids circulating rate regulation by plate valve installed in standpipe under negative pressure gradient

In a large scale circulating fluidized bed(CFB)device,an experimental study was conducted on the relationship between solids circulating rate and opening rate of plate valve installed in the standpipe under negative pressure gradient.The fluidized patterns and pressure fluctuations above and below the plate valve were measured for analyzing the plate valve operation process.Experimental results showed that there was a critical opening rate of plate valve,which divided the opening of the plate valve into uncontrolled range and controlled range for solids circulating rate regulation.When opening rate was greater than the critical value,the plate valve had no action on solids circulating rate regulation.The fluidized patterns above and below the plate valve were the same,and the pressure fluctuation profiles were similar.When open rate was smaller than the critical value,the plate valve had the function of solids circulating rate regulation.The fluidized pattern above the plate valve was moving bed,and the fluidized pattern was like raining flow below the plate valve.The pressure fluctuation profile above the plate valve was different from that below the plate valve.