6 replies to this topic

Normally, a differential pressure transmitter is installed across any Power Operated Emergency Isolation Valve in liquid service in order to prevent opening the valve against high differential pressure which may cause hydraulic shock and damage the downstream piping.

My subject is:

Is this also required across valve in hydrocarbon gas service?

[Qalander (Chem)]

Normally, a differential pressure transmitter is installed across any Power Operated Emergency Isolation Valve in liquid service in order to prevent opening the valve against high differential pressure which may cause hydraulic shock and damage the downstream piping.

My subject is:

Is this also required across valve in hydrocarbon gas service?

Sorry@KMB@, Your query is not that clear right now,
Please explain what you exactly require and what is the service perspective or background?

[ankur2061]

Normally, a differential pressure transmitter is installed across any Power Operated Emergency Isolation Valve in liquid service in order to prevent opening the valve against high differential pressure which may cause hydraulic shock and damage the downstream piping.

My subject is:

Is this also required across valve in hydrocarbon gas service?

KMB,

Your query is very clear to me.

The answer is:

No it is not required in HC gas service. The reason is:

HC gas is a compressible fluid and there is almost no possibility of hydraulic shock/line packing as observed in liquid service. This has been discussed earlier in the forum and you may want to use the search engine to find about no shock waves generated in gas service.

Hope this helps.

Regards,
Ankur.

[ankur2061]

Normally, a differential pressure transmitter is installed across any Power Operated Emergency Isolation Valve in liquid service in order to prevent opening the valve against high differential pressure which may cause hydraulic shock and damage the downstream piping.

My subject is:

Is this also required across valve in hydrocarbon gas service?

KMB,

I would like to make an addition to my earlier reply. If the sole purpose of the DP transmitter is to prevent hydraulic shock in the downstream piping then what I mentioned earlier about DP transmitter not required in HC gas service is correct.

However, while discussing with some of my learned colleagues I found out that the DP transmitter function is more than to prevent hydraulic shock downstream. A high DP across the EI or ESD valve can also cause damage to the valve seat when opened. If this is also to be the criteria for installing a DP transmitter then I stand corrected and there may be a requirement of the DP transmitter even in HC gas service. However, to conclude the requirement of the DP transmitter, a more detailed case-to-case analysis would be required.

Waiting for a feedback from you.

Regards,
Ankur.

Normally, a differential pressure transmitter is installed across any Power Operated Emergency Isolation Valve in liquid service in order to prevent opening the valve against high differential pressure which may cause hydraulic shock and damage the downstream piping.

My subject is:

Is this also required across valve in hydrocarbon gas service?

Sorry@KMB@, Your query is not that clear right now,
Please explain what you exactly require and what is the service perspective or background?

The point is the effect of opening a valve with high DP, in liquid and gas services. Thanks

Normally, a differential pressure transmitter is installed across any Power Operated Emergency Isolation Valve in liquid service in order to prevent opening the valve against high differential pressure which may cause hydraulic shock and damage the downstream piping.

My subject is:

Is this also required across valve in hydrocarbon gas service?

KMB,

I would like to make an addition to my earlier reply. If the sole purpose of the DP transmitter is to prevent hydraulic shock in the downstream piping then what I mentioned earlier about DP transmitter not required in HC gas service is correct.

However, while discussing with some of my learned colleagues I found out that the DP transmitter function is more than to prevent hydraulic shock downstream. A high DP across the EI or ESD valve can also cause damage to the valve seat when opened. If this is also to be the criteria for installing a DP transmitter then I stand corrected and there may be a requirement of the DP transmitter even in HC gas service. However, to conclude the requirement of the DP transmitter, a more detailed case-to-case analysis would be required.

Waiting for a feedback from you.

Regards,
Ankur.

Yes, the concern is the hydraulic shock in the downstream piping. However, I agree with you that avoiding damaging the valve needs to be considered unless the valve is designed to work under this condition. Thanks a lot.

[Qalander (Chem)]

Normally, a differential pressure transmitter is installed across any Power Operated Emergency Isolation Valve in liquid service in order to prevent opening the valve against high differential pressure which may cause hydraulic shock and damage the downstream piping.

My subject is:

Is this also required across valve in hydrocarbon gas service?

KMB,

I would like to make an addition to my earlier reply. If the sole purpose of the DP transmitter is to prevent hydraulic shock in the downstream piping then what I mentioned earlier about DP transmitter not required in HC gas service is correct.

However, while discussing with some of my learned colleagues I found out that the DP transmitter function is more than to prevent hydraulic shock downstream. A high DP across the EI or ESD valve can also cause damage to the valve seat when opened. If this is also to be the criteria for installing a DP transmitter then I stand corrected and there may be a requirement of the DP transmitter even in HC gas service. However, to conclude the requirement of the DP transmitter, a more detailed case-to-case analysis would be required.

Waiting for a feedback from you.

Regards,
Ankur.

Yes, the concern is the hydraulic shock in the downstream piping. However, I agree with you that avoiding damaging the valve needs to be considered unless the valve is designed to work under this condition. Thanks a lot.

Dear @KMB@ Hello,
As indicated in my response to your OP that your query was 'vague/unclear'

Even after all the above discussion by our forum's learned and helping colleague; exact reply to your query was not however possible.

This was the reason to request for
1)Properly phrased query providing maximum needed data/parameters related to any query.
2)Whether it is a set of conditions or appropriate sketch with conditions earmarked on it.

Thus it is re-iterated as many a time mentioned by Art. that initial query must be better/accurately phrased to help the person making query and to help those who put their time and energies to help him/her.

This is not to hurt any body's feeling but a humble proposition to facilitate things better and focused manner.
Best Regards
Qalander