Q & A > Question Details
in a SRU final condenser demister pad, dislocations occurred two times recently. Due to this the tail gas line to the TGTU filled with sulphur. What may be the reasons and remedies?
Also, in case of carryover of sulphur what ways are there for early removal of sulphur.
03/07/2020 A: Pronab Mistry, ADNOC Gas Processing, pronab88@yahoo.com
In addition to Eric Vetters and Celso Pajaro, I want to add the following:
Is there any pressure surge which can cause the demister pad to fall down? Maintain the last condenser temperature at 5 to 7 deg C more than the sulphur condensation temperature(Usually 118 ~120 Deg C). I presume there is steam coils inside the demister pad of the last condenser; if not you will always face this type of problem. Ensure these steam coils are working properly. Make sure steam traps are working fine. You can do a hydro test of the steam coils and ensure that they are healthy.
If the last condenser temperature is too high, sulfur vapour will not condense; it will carry over and condense in the cold area. Make sure you operate the last condenser at optimum temperature.
22/06/2020 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Assuming the pad was installed properly, it sounds like excessive pressure drop exceeded the limits of the hold down clips on the existing demister. Normally things like trays, packed beds, demister pads, etc. are designed for some maximum DP. If that DP is exceeded the device can become dislodged.

In this case either the rate is exceeding the unit design limits and causing DP to increase, or more likely something is plugging the demister and restricting flow/increasing DP. If the temperature gets too low liquid droplets captured by the demister pad can solidify instead of draining. Such a happening can cause DP to build to the point that the demister pad is blown out. Possible causes for getting too cold are excessive process side cooling (most likely at turndown conditions), problems with the steam jacketing system, or loss of temperature during an unplanned shutdown.

Carry over will tend to collect at low points in the process. If you have properly designed drains you should be able to drain liquid from the low points. Because of the way sulfur will set up, proper design of drains is not a trivial exercise.
22/06/2020 A: Celso Pajaro, Sulzer Chemtech, celso.pajaro@sulzer.com
Please check the mist eliminator fixation system. If it uses tie wire please replace it with a clamp system; that will reduce the likelihood of dislocation.