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.