3 replies to this topic

[benabed]

Dear freinds,
We want to use a pilot operated safety valve taken from the store as a replacement for the existing sping loaded safety valve on the centrifugal compressor discharge drum. Operating pressure is 130 barg and the set pressure is 140 bargs. So what parameters other than the relieving capacity we should take in consideration in order to be sure that the spar valve will performe as expected.

Awaiting your valuables contributions to make a final decision.

Regards
L.Benabed

[ankur2061]

Dear freinds,
We want to use a pilot operated safety valve taken from the store as a replacement for the existing sping loaded safety valve on the centrifugal compressor discharge drum. Operating pressure is 130 barg and the set pressure is 140 bargs. So what parameters other than the relieving capacity we should take in consideration in order to be sure that the spar valve will performe as expected.

Awaiting your valuables contributions to make a final decision.

Regards
L.Benabed

Benabed,

I prepared a comapny standard for a middle east O&G company titled "Specification for Vent & Depressurization System" and one section deals with types of Relief Devices. I am reproducing verbatim the content of the section relevant to your post:

quote
Spring Loaded Relief Valves

a. Conventional spring loaded relief valves.
These shall be installed where back-pressure does not exceed 10% of the set pressure. These are the
recommended type for TRV’s.
b. Balanced pressure relief valves
These are suitable for back-pressures ranging from 10% to 50% of the set pressure. They can be of
two main types : balanced piston and balanced bellows. Balanced bellows shall be given preference
where the fluid is corrosive or fouling.

Pilot-Operated Relief Valves

Pilot-Operated valves are recommended for applications where the back-pressure on the valves are very high (typically 50% or higher). The other criteria for selecting pilot-operated valves are as follows:

a. Low accumulation rates are required.
b. The set pressure is required to be close to the operating pressure.
c. Calibration is required without removing the valve.
d. Handling of large relief flows are required.
e. The service is non-fouling.
unquote

Hope this helps.

Regards,
Ankur.

[benabed]

Dear freinds,
We want to use a pilot operated safety valve taken from the store as a replacement for the existing sping loaded safety valve on the centrifugal compressor discharge drum. Operating pressure is 130 barg and the set pressure is 140 bargs. So what parameters other than the relieving capacity we should take in consideration in order to be sure that the spar valve will performe as expected.

Awaiting your valuables contributions to make a final decision.

Regards
L.Benabed

Benabed,

I prepared a comapny standard for a middle east O&G company titled "Specification for Vent & Depressurization System" and one section deals with types of Relief Devices. I am reproducing verbatim the content of the section relevant to your post:

quote
Spring Loaded Relief Valves

a. Conventional spring loaded relief valves.
These shall be installed where back-pressure does not exceed 10% of the set pressure. These are the
recommended type for TRV’s.
b. Balanced pressure relief valves
These are suitable for back-pressures ranging from 10% to 50% of the set pressure. They can be of
two main types : balanced piston and balanced bellows. Balanced bellows shall be given preference
where the fluid is corrosive or fouling.

Pilot-Operated Relief Valves

Pilot-Operated valves are recommended for applications where the back-pressure on the valves are very high (typically 50% or higher). The other criteria for selecting pilot-operated valves are as follows:

a. Low accumulation rates are required.
b. The set pressure is required to be close to the operating pressure.
c. Calibration is required without removing the valve.
d. Handling of large relief flows are required.
e. The service is non-fouling.
unquote

Hope this helps.

Regards,
Ankur.

Dear ankur,

Thank you for the reply, but not sure if the new valve is suitable for the application or not. I can understand from your reply that we can use a pilot-operated valve instead of a spring loaded as far as the capacity is the same.

[JoeWong]

Replace spring loaded pressure relief valve with pilot-operated relief valve is possible but shall assess properly... Couple of things :

(i) material suitability
(ii) capacity
(iii) set pressure
(iv) potential of blockage of pilot line
(v) certification
.
.
.

I believe obtain advice from the pilot-operated relief valve vendor is the best source of information.

Will add if cross my mind...