Welding on Sulfur Tank with Molten Sulfur Inside

[refiner258]

Good day!

Anyone who has experienced welding on a tank with molten sulfur inside? Are there any references or codes and standards that allow this? From my research, liquid sulfur has relatively low auto ignition temperature, so is sulfur vapor cloud and dust.

Thank you!

 

[MJCronin]

Make sure that you take videos, pictures and document all methods.

These could be very important in the near future !!!!

MJCronin
Sr. Process Engineer

 

[EdStainless]

If you are making small tack welds on the outside of thick material, then maybe.
If these are structural welds, no way.
Even if the tank is inert gas blanketed and fire isn't a concern there is still the issue of hte S reacting with the hot steel.

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P.E. Metallurgy, Plymouth Tube

 

[refiner258]

To MJCronin,

Thank you for your response. As of now, we have no plans yet of pursuing the welding activity. But your suggestion to document everything is duly noted.
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To EDStainless,

Thank you for your response. Our purpose of welding while tank is in service is to temporarily patch a holed through section of our tank. Hole is only ~1.5" in diameter. I am not sure if intermittent tack welding until the plate patch has sealed the hole will be a viable option. Aside from fire, what are the other concerns in doing this? Which reaction are you pertaining to with sulfur reacting with hot steel? Is it the change in viscosity?
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[Compositepro]

The chemistry of sulfur is similar to oxygen so, yes sulfur will react vigorously with hot steel.

 

[EdStainless]

If you are trying to patch a leak then don't do it.
Even very small amounts of S in the weld will result in very poor welds and the likelihood of cracking.
In a number of cases I have had people tell me that they cannot even do weld repairs on S equipment because they can't get it clean enough to get good welds.

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P.E. Metallurgy, Plymouth Tube

 

[racookpe1978]

Is there any "soft" metal he could use that would minimize reactions with the liquid sulfer? Either as a hammered-in external plug, or as a external wrap or (literally) applied like a band-aid to stop the leak until the tank can be drained far enough and cooled down to expose the inside for proper cleaning to bare metal for welding?

 

[EdStainless]

My real thought is that if there is a leak in the tank they should be draining and cleaning it for a full inspection.
If it is through wall in one place likely the entire tank is junk, or at least a band of it at that elevation is bad.

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P.E. Metallurgy, Plymouth Tube

 

[refiner258]

To Compositepro:

Thank you very much for your response.
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To racookpe1978 and EdStainless:

Thank you very much also for your response. location of the leak is at the fourth course plates of the tank (approx. 6 m from tank bottom). We reduced tank level to around 2m and conducted thickness survey at the vicinity of the hole. We then applied adhesive and sealed the hole using a plate. You may refer to the attached file. We have also recommended to limit tank level up to only 5.5 m. Please take note that what we did was temporary. We are planning to shutdown tank for inspection.

What if sulfur is on the other side where welding is conducted, will it still produce poor welds? Apart from the poor welds, what are the other concerns?

Thank you.
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[georgeverghese]

Does this help ?

https://www.youtube.com/watch?v=A5H6DVe5FAI

 

[hacksaw]

getting legitimate advise on a repair involves engineering, so at a minimum you need provide the following:

1. a picture of the tank you are concerned with

2. an engineering drawing of the vessel