Light naphtha has a high sulfur content

In the cracking unit, the light naphtha usually contains inorganic sulfur; adjustments are primarily made in the hydrogen sulfide removal stripping tower, 1. by increasing the stripping steam. 2. Appropriately reduce the tower pressure.

Is there nothing wrong with sampling, or is it a problem with the equipment?

If this unit was newly built, or if this problem has existed since its initial operation, it is likely that the design of the hydrogen sulfide stripping tower does not meet the requirements; in such cases, it may be necessary to redo the calculations and replace the tray design. If this problem arises suddenly during operation, and measures such as increasing the stripping steam or reducing the tower pressure fail to resolve it, then it is due to salt deposition on the trays of the hydrogen sulfide removal stripping tower.

This unit has been in operation for over two years; after this shutdown for maintenance, it will operate in the same way. A similar situation occurred last year – at that time the sulfur content of the raw materials used was high, so we switched to raw materials with a lower sulfur content, and as a result the sulfur content in our light naphtha decreased. The sulfur content in our light naphtha is…

So what is the sulfur content of the raw material this time? If it’s similar to the previous failure, then it’s likely that the design didn’t take high-sulfur raw materials into account. If everything is normal, it should not be a problem with the hydrogen sulfide stripping tower. You have just completed maintenance, so the trays should have been inspected; moreover, did you carry out operations such as introducing steam and reducing the tower pressure to see if that brought any improvement? The same working conditions can’t fail this time. I’m not sure what your process for producing lightweight stone is like – do you have a butane removal tower or something similar? Hydrogen sulfide in lightweight stone is mainly present in the liquefied gas; you might try to improve the efficiency of removing this substance from the liquefied gas, so as to bring its carbon5 content as close as possible to the specified levels, to see if that can help improve the quality. Looking forward to continuing to follow this post.

Inorganic sulfur is related to the stripping issue, while organic sulfur is related to the reaction issue