Sulfur plant PSVs?

[kasiabron]

Hi, I have a project to do on sulfur plants safety. We had out seal pots relieve the overpressure and our PSVs that are located at the front end of the plant, popped at 20 psig even thought set pressure was 15 psig. Anyone can give me contact people who have sulfur plants? I am interested in finding out what other options there are for safety if the PSVs are eliminated.

 

[brochon]

The process side of a SRU is usually designed for a maximum pressure of 15 psig. This is to avoid classing the equipment on the process side as pressure vessels.

Most SRUs that I have seen do not have PSVs on their process side. Air blowers are typically chosen to have dead head pressure of 10 psig. Therefore, SRU design pressure is never exceeded. The depth of the Seal Leg is determined by air blower dead head pressure + 2 or 3 psig = 12 or 13 psig. Therefore, seal legs are never blown out.

Thx brian

 

[RogerH]

Kasiabron
Another safety option is to shutoff the supply (acid+sour gas) on high (front) pressure.Seen that on one plant and it works fine (as long as the purge to the instrument leg is working).
Safety valves on the SRU front should be avoided unless you can route the discharge to a (very) safe location.