The lining at the catalytic double-acting slide valve tends to peel off
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Have you encountered the issue of the lining coming off at the catalytic double-acting slide valve? What is the cause? Is it due to a large pressure drop before and after?
As one of the means for controlling the regeneration pressure, the double-acting slide valve is usually kept at a low opening degree; generally, efforts are made to open the butterfly valve at the flue gas exhaust fan inlet as wide as possible, so that the fan can do more work. In most cases, the flue gas follows this pathway, so the erosion of its lining by the flue gas is relatively low. The phenomenon you mentioned is mostly caused by poor results when drying the lining, as well as substandard construction quality. Of course, there are also issues caused by problems with the double-acting spool valve itself.
1. Under normal conditions, the double-acting slide valve, as one of the means for controlling regeneration pressure, operates within a very narrow range; in most cases it allows the flue gas to do more work. The scouring effect of flue gas and the catalyst particles it carries on them is relatively small. 2. The main reasons for the shedding of the lining are as follows: the quality of the lining, whether the heating process is proper, the operating condition of the double-acting slide valve, and the wear of the catalyst in the flue gas.
There is also a possibility that the double-acting spool could be damaged.
I have categorized it under the operating conditions of double-acting slide valves; similar phenomena have indeed occurred in some other units.
I encountered a similar situation before, and after making some optimizations, I didn’t run into this issue anymore. Except during startup/shutdown or accident conditions, the opening degree of the double-acting slide valve shall not exceed 1%. What is the opening degree of your dual-acting slide valves?
What’s going on here? Have you guys encountered this before?
The gate plate fell off and bent upward past the valve stem, causing the valve track to weld apart.
If it’s due to erosion, it usually occurs in the pipeline below the spool; but right now we have hot spots above the spool
The main reason is that the temperature during lining baking did not reach the required level