Main reasons for tube failure in the membrane water wall inside the Shell powder gasifier
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Dear sea friends, please use your intelligence and engage in active discussions regarding the main reasons for tube failures in the membrane-type water wall inside the Shell powder gasifier I hope everyone will feel free to share their insights and actively participate in this discussion, so as to provide technical guidance for users of Shell powder gasification technology in China!
There is nothing else; only purity, free from imperfections and falsehoods.
The reasons for tube bursts in the water wall are as follows: 1. Excessively high furnace temperature； 2. The heat-resistant layer peels off or slag adheres poorly to the wall ； 3. Inadequate cleaning of the water pipes, with clogged flow control orifice plates resulting in empty pipes or low flow rates.
The water pipe has insufficient flow rate, and high temperatures cause the pipe to burst.
It might be due to an excessively high vaporization temperature, which causes the SiC layer to peel off; the slag then directly erodes the water wall, thinning its walls and ultimately leading to tube failure.
Poor water quality causes pipeline blockages, and pipes burst under high temperatures
1. Too low a circulating water volume can also be the cause. 2. Defects in the pipes can also be the reason. 3. High outlet steam pressure can also be the issue
How is a burst tube in Shell’s gasifier water wall repaired? Should a reinforcement plate be welded on top, or should that tube be discarded? Who can answer this?
Given all that has been mentioned, has anyone thought about the fact that welding techniques used on the pipes themselves are also important? There was a manufacturer in a similar industry whose steam generator had to be shut down due to poor welding skills; at that time, a crack appeared in the weld of one of the pipes imported as E1306, which caused severe blockage at the cross-section of the pipe
Tube ruptures still happen; I’ve seen one break neatly in two. . . . . . . . The specific reason is unknown. . . . . Probably a quality issue
Could it be that uneven water flow, or some other factor, leads to uneven heating of the pipe walls, resulting in excessive thermal stress and thus pipe rupture?
For gasifiers that have not been operated with a shell, the problem is likely similar to that of boiler water wall tube failures: uneven slag deposition and localized erosion lead to thinning of the water wall