12 replies to this topic

[aju_1807]

Dear All,

Can somebody explain the basis for having heat tracing for pilot operated relief valves? The ambinet condition is as below:

Maximum : 55 deg C
Minimum : -5 deg C

As per the hydrate study report conducted for our project there is no possibility of hydrate formation but is there any guideline for having heat traing for pilot operated relief vales to avoid the choking of pilot (wehich is basically thin tubing part).

Appreciate if someone can share their experence here on this subject.

REgards,

AJ

[ankur2061]

Dear All,

Can somebody explain the basis for having heat tracing for pilot operated relief valves? The ambinet condition is as below:

Maximum : 55 deg C
Minimum : -5 deg C

As per the hydrate study report conducted for our project there is no possibility of hydrate formation but is there any guideline for having heat traing for pilot operated relief vales to avoid the choking of pilot (wehich is basically thin tubing part).

Appreciate if someone can share their experence here on this subject.

REgards,

AJ

AJ,

See the attached presentation for Relief valves. It is excellent. For heat tracing guidelines you can refer the folllowing link:

http://www.fluidcont...T102Tracing.pdf

Hope this helps.

Regards,
Ankur.

Attached Files

•  Pressure Relief Devices Scott Ostrowski.ppt   1.72MB   325 downloads

[aju_1807]

Ankur,

Thanks for reply.

I have this ppt file and its very informative but it does not provide any information realted to requriement of heat tracing for pilot operated relief valve..

I dont know how to decide the requiremnet of heat tracing for pilot of pilot operated relief valve. Please note our service in neither congealing nor viscous fluid.

Appreciate if some one can help me on this subject.

Regards,
AJ

[ankur2061]

Ankur,

Thanks for reply.

I have this ppt file and its very informative but it does not provide any information realted to requriement of heat tracing for pilot operated relief valve..

I dont know how to decide the requiremnet of heat tracing for pilot of pilot operated relief valve. Please note our service in neither congealing nor viscous fluid.

Appreciate if some one can help me on this subject.

Regards,
AJ

AJ,

Your service is not congealing, viscous nor there is any possibility of hydrate formation then why on earth do you require heat tracing. From what all you have described there is no need for any heat tracing.

Hope this helps.

Regards,
Ankur.

[ogpprocessing]

AJ,

Your service is not congealing, viscous nor there is any possibility of hydrate formation then why on earth do you require heat tracing. From what all you have described there is no need for any heat tracing.

Hope this helps.

Regards,
Ankur.

Dear Ankur,

Do you believe that heat tracing is effective for flare network lines keeping in mind that flare gas streams are fast in nature and the heat transfer is poor?

[ankur2061]

AJ,

Your service is not congealing, viscous nor there is any possibility of hydrate formation then why on earth do you require heat tracing. From what all you have described there is no need for any heat tracing.

Hope this helps.

Regards,
Ankur.

Dear Ankur,

Do you believe that heat tracing is effective for flare network lines keeping in mind that flare gas streams are fast in nature and the heat transfer is poor?

This is what API STD 521 has to say about heat tracing:

6.6.4 Viscosity & solidification

In the selection of a disposal system for liquids & condensable vapours, the production of highly viscous or solid materials warrants consideration. The design of a disposal system for such materials may require heat tracing of valves & discharge lines. The formation of gums, polymers, coke, or ice that might prevent the safe operation of the discharge system should also be considered in the design

Regards,
Ankur.

[ogpprocessing]

API statement refers to viscous services and not hydrate formation. Heat tracing is good to keep some parts of the process hot or warm so can be effective for viscous services but for hydrate formation concern will not be effective.

[ankur2061]

API statement refers to viscous services and not hydrate formation. Heat tracing is good to keep some parts of the process hot or warm so can be effective for viscous services but for hydrate formation concern will not be effective.

ogpprocessing,

You concentrated on the exact terminology and overlooked the overall context of the paragraph. It also says about 'solid' materials & we all know that hydrates form as solid plugs in the system.

Regards,
Ankur.

[ogpprocessing]

ogpprocessing,

You concentrated on the exact terminology and overlooked the overall context of the paragraph. It also says about 'solid' materials & we all know that hydrates form as solid plugs in the system.

Regards,
Ankur.

Solid material can be anything can be polymerized material. Even if we find that by Solid API refers to hydrate common sense of engineering reject the heat tracer option as a protection against hydrate formation.

[ankur2061]

Solid material can be anything can be polymerized material. Even if we find that by Solid API refers to hydrate common sense of engineering reject the heat tracer option as a protection against hydrate formation.

Leaving apart API I certianly know that people who have written Shell Design Engineering Practices (I hope you do understand what I am referring to) have more common sense than you and me based on years of operating experience gathered by them. Here is what they have to say in DEP 80.45.10.10-Gen.

To prevent hydrate or ice formation due to small leaks across the valve or low ambient temperatures, heat tracing shall be installed.

[ogpprocessing]

Leaving apart API I certianly know that people who have written Shell Design Engineering Practices (I hope you do understand what I am referring to) have more common sense than you and me based on years of operating experience gathered by them. Here is what they have to say in DEP 80.45.10.10-Gen.

Please keep in mind that this statement is part of an engineering practice. This is not standard or code. Other engineering practices contain different ideas. That is why we see for similar subjects (for example hydrate formation at flare network) some of the companies ignore about this concern (I do agree with them) and some of them even provide hydrate inhibitor injection and heat tracer at the same time!

Engineering practice is a matter of conservatism not requirements.

[ankur2061]

Please keep in mind that this statement is part of an engineering practice. This is not standard or code. Other engineering practices contain different ideas. That is why we see for similar subjects (for example hydrate formation at flare network) some of the companies ignore about this concern (I do agree with them) and some of them even provide hydrate inhibitor injection and heat tracer at the same time!

Engineering practice is a matter of conservatism not requirements

Then I suggest we end this topic with the concluding remarks that whatever engineering practice a company or an individual feels comfortable & accustomed with based on their collective experience should be the one that they should adopt. I am conservative enough to provide heat tracing on a flare line if it is established that hydrates can form in the line due to low temperatures.

Regards,
Ankur.

[ogpprocessing]

Then I suggest we end this topic with the concluding remarks that whatever engineering practice a company or an individual feels comfortable & accustomed with based on their collective experience should be the one that they should adopt.

We have not started this topic so we can not advice to end this topic. I am willing to know other ideas from experts and experienced people.

I am conservative enough to provide heat tracing on a flare line if it is established that hydrates can form in the line due to low temperatures

Instead I prefer:
1. Not to follow the engineering practices blindly
2. Save money
3. Not to provide heat tracer for applications which are not effective.