TSV (Thermal safety valve)Blockage in sea water piping

piiengineers · Post by **piiengineers** » 18 Sep 2010, 12:31

We are facing frequent problems of chocking (salt deposits)of small bore TSV's(3/4" & 1")in sea water cooling water piping systems(cement lined).Is there practical remedy to resolve the above issue?Anybody used rupture at the TSV inlet to avoid the same?Please shrare your experiecne in this regard.The water temperature is within the design conditions.

with advance thanks,

ben · Post by **ben** » 18 Sep 2010, 18:04

Have you tried replacing the TSV or it's a chronic problem?
What do your process engineers say about this?

piiengineers · Post by **piiengineers** » 19 Sep 2010, 06:33

It is chroic problem and already others may be experiencing the same. I need an industrial best practice to avoid the same by some modification in the system.

sharjeel · Post by **sharjeel** » 19 Sep 2010, 08:05

As thermal safety valve comes only into play at cooling water services when header is isolated on both sides and there is no relief available in case of fluid expansion due to temperature changes in between the isolations, so there could be three ways to protect piping against thermal expansion.
1. Simply installing a TSV that is the most common method but cannot be used in case of choking behavior of the fluid
2. Rupture disk that can be very effective in cases where fluid in not very expensive or its local drainage is not an issue, and frequent choking issues are faced.
3. A combination of Rupture disk and TSV can also be used but in that case you have to provide a pressure gauge in the BD chamber (space between rupture disk and TSV) to know if the rupture disk is intact or got fractured.
Method 2 and 3 can be used effectively based upon the requirements.

Post by **Imran.Idris** » 20 Sep 2010, 10:13

Thermal PR valve is needed for sections of piping 100 ft (30 meter) or more in length which can be blocked in by metal seated valves, and all volumes which can be blocked in by soft seated valves, shall be protected against thermal expansion. Protection shall be provided by a 3/4" NPS (20 mm) "thermal relief" PR valve set to relieve at 133% of the MAWP of the pipe.
Exxon basic practices allows an alternate to thermal relief protection in the following words.
As an alternative, a bypass and check valve may be installed around a block valve where leakage through the check valve is acceptable

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