On the coking problem at the slag discharge port of circulating fluidized beds
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Recently, our plant’s circulating fluidized bed has been experiencing production disruptions due to coking at the slag discharge outlet. After shutting down the furnace to remove the slag, it was found that coking only occurred at that outlet, with no such issue elsewhere. It is preliminarily assumed that after stopping the slag cooling machine, air entered the slag discharge outlet through the inspection pipes, leading to low-temperature coking. Could anyone please suggest some effective solutions? Thank you
Try improving the sealing of the slag discharge pipe of the cold slag machine.
It may be that the fluidization near the slag discharge port is poor, resulting in localized coking. Check the condition of the air caps; directional air caps should be installed around the slag discharge opening during major repairs
The concept of low-temperature coking is that the overall bed temperature is not high enough to reach the softening temperature of the ash, and local high-temperature coking occurs due to poor local fluidization. It’s not the cold wind that comes in and causes the temperature to drop, leading to coking. As long as coking occurs, it means that the combustion temperature has reached or is close to the softening temperature of the fuel.
This post was last edited by han*chen on 2017-9-20 09:06. This is a great suggestion; the power plant where I used to work was upgraded in this way by installing directional air caps around the slag discharge openings during major repairs.
Thank you, I checked it and there was a crack; after fixing it, the problem was resolved. Thank you so much indeed
The entry of air can also lead to low-temperature coking. If the slag discharge port is not properly sealed, the unburned substances in the slag continue to burn when exposed to air, resulting in excessively high temperatures that cause coking; poor sealing indeed leads to such a situation
It’s okay; feel free to communicate if there are any issues.