6 replies to this topic

[luuquocdai]

Dear all friends,
I have a problem which I want to get consults from you.
I'm working with Heavy Fuel Oil system, all pipeline need to tracing by steam for insulation.
Estimate that we know exactly the total pipe length (because pipe layout for this system was completed).
I'm looking forward information from you.
Thanks in advance.

Luu Quoc Dai from Vietnam
Email: luuquocdai@gmail.com

Edited by luuquocdai, 09 July 2010 - 10:26 PM.

[herrani]

Hi Luu Quoc Dai

I am not sure if there is a better way of calculating it, but if you know the temperature that the heavy oil would have without steam tracing, and the minimum temperature required in your pipelines (I guess it is close to the pour point of the oil) then you can calculate how much heat you need: the enthalpy difference between the two cases. Based on that, you can figure out how much steam is required.

Based on the total amount of steam required, and the layout configuration, you can estimate the amount of steam you need to heat each pipe, and based on that you will know the pipe size.

Maybe there is some standard size that is always used instead?

[Jason W.]

Hi Luu,

We typically will use 1/4" copper tubing (easy to form) and low-pressure steam (60 psi) for all of our heat tracing. The copper is secured to the pipe with copper wire and then wrapped in asbestos free insulation. Of course don't forget that you will have a fair amount of condensate on the back side of this heat trace, I'm sure you can use it for a pre-heating step somewhere.

Also, take a look at the critical temperatures of your fluid. You will want to make sure that you aren't "cooking" the fluid however, you want to make sure that you add enough heat that it retains fluid characteristics.

Jason

Edited by Art Montemayor, 09 July 2010 - 01:30 PM.

[ankur2061]

Hi,

Have a look at this link from our good old cheresources:

http://www.cheresour...m_tracing.shtml

This should help.

Regards,
Ankur.

Edited by ankur2061, 09 July 2010 - 10:47 AM.

[luuquocdai]

Thanks ankur, Jason and herrani. Thanks for your help.

[luuquocdai]

Dear Ankur
Many thanks for your help.
But I think that, there is a misunderstanding in here. The process fluid's temperature is fixed.
I mean that, the temperature of fluid inside pipe is fixed.
Now I want to calculate the pipe size of steam pipe and steam flowrate for my system with the fluid's temperature fixed above. Steam's properties are fixed too (because we have to connect to battery limit which has only one type of steam - saturated steam).
I think it is clear enough for my question.
Please help me if you have any ideas.
Thanks in advance.

Luu Quoc Dai, from Vietnam

[Art Montemayor]

Luu Quoc Dai:

I believe the misunderstanding is on your part. Ankur has certainly furnished you with the correct, referenced information that can not only assist you, but also resolve your problem.

It is almost always assumed that the piped process fluid has a constant temperature. The furnished information does so also.

You calculate the amount of saturated steam required to carry out the steam tracing and, from this quantity, design the tubing size.

There are various ways you can design the tracing you want to apply. As the spreadsheet explains, you can use the direct contact method (more efficient) or use bare tracing. Both basic methods require pipe insulation around the entire assembly. You can use parallel segments all along the pipe length, or you can use one, singular steam tubing run with intermediate condensate takeoffs to handle the condensate load and keep the tubing doing effective tracing. It all depends on your decision and needs.

In any event, Ankur has certainly given you the correct information.