Why the slag discharge tube of circulating fluidized bed boiler will be blocked?

(Details on the problem) Specific Performance:

Slagging pipe blocks during operation of circulating fluidized bed boiler.

Answer：cause of failure:

(1) The internal shape is caused by the limited expansion of the wear-resistant material inside the slag discharge pipe. The internal components of the slag cooler are deformed, affecting the fluidization of the slag cooler; the slag cooler is deactivated for a long time or a single slag cooler is selected for slagging, and the bed material in the deactivated slag cooler is bonded under the influence of steam, which being low temperature coke.

(2) The operating personnel did not grasp the ratio of the fluidized air volume of the slag cooler. Inappropriate air volume ratio resulted in poor ash slag fluidization in the slag cooler.

Troubleshooting:

(1) Operation personnel should strengthen understanding of boiler operating conditions, adjust boiler parameters in a timely manner, set up the concept of boiler material dynamic balance, control boiler operating bed pressure at normal values, and try to avoid large boiler slag discharge.

(2) The slag cooler hood should be purged each time the boiler is stopped. It is found that the blocked hood must be opened to control the size of the fuel.

(3) Boiler slagging, slag cooler should be carried out alternately; the slag entering the slag cooler should be fully cooled to ensure the working conditions of slag cooler.

(4) Summarizing the experience of the fluidization air volume of the slag cooler, select the optimization parameters of the squid air volume in each plenum, including the lowest fluidization air volume of the slag cooler to ensure the normal fluidization of the slag cooler under any load.