Frequent trip of slum shut off valve.

[Joseph Badu mensah]

On our pressure regulating skid (4"), one of the two slum shut valves on the line trips frequently with a low-pressure indication on the SCADA. Due to the frequent trips, we have engaged both lines to run simultaneously to avoid tripping the turbines in the event of the SSV shut. Both SSV has different pressure set points 33.1barg and 32.5barg respectively with regulator set pressure of 28.9barg.

I have two questions:

1. What must be the cause the frequent shut of the SSV.
2. Is it practically advisable to run both lines simultaneously
3. Is it practically prudent to give the SSV's different set values.

 

[LittleInch]

P &ID with set points please.

Have you calibrated all the pressure transmitters?

Why does the valve close on low pressure?

To have even an educated guess you need to give us the full picture.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[alchemon]

Why is your slam shut set to trip on low pressure? That's not usually the case

 

[LittleInch]

1. What must be the cause the frequent shut of the SSV.
NO idea - You've provided no information to even hazard a guess other than something in the logic is triggering the valve closure. Are these actuated electronically or pneumatics?

2. Is it practically advisable to run both lines simultaneously
Yes, but normally you need to set the regulators different, one lower than the other by may 1 to 1.5 bar. The lower regulator will normally be close, but if the other stream closes it takes over pretty seamlessly, so long as the pressure regulating valve can open fast enough.

3. Is it practically prudent to give the SSV's different set values.
Again yes, but the difference seems very low. /normally needs min 1.5 barg at this sort of pressure (5%)

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.