Isokinetic sample probe design 1

[Tuckabag]

A client has requested that we put forward a proposal for design/manufacture of isokinetic sample probes for use on a high pressure, natural gas pipeline in 2 phase regime.
We have a lot of experience in non-isokinetic probe design, however I am struggling to find a standard that provides design criteria for high pressure, isokinetic sampling.
ASTM D1066 is steam based and apparently has design detail for probe nozzle designs, however I am hesitant to buy a copy if there is no relevant information in there with regards to hydrocarbon sampling.
Is anyone familiar with this standard? And if so, does it include reference for hydrocarbon sampling?

Are there any other standards I should be taking a look at that could be of assistance?

Thanks.

 

[LittleInch]

I had to go look up what iso kinetic was, but now understand.

first off I can understand why the client wants this, but what form is your 2 phase flow in?

Anything other than misty flow you won't really get a representative sample.

There are al sorts of options out there to study - this was a nice one

http://www.brighthubengineering.com/power-plants/98903-what-is-isokinetic-sampling/#imgn_0

but I guess you're looking for something more specific?

I've done sampling of two phase flow, but only once it came out of a separator and then re-combined the results based on mass flow of the two elements.

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

 

[Tuckabag]

We dont have a stream composition or P/T data yet to enable us to produce a phase envelope, however client is certain they are in 2 phase flow and most likely have MEG entrained as well.

And yes, looking for something more specific with regards to standards for iso kinetic sampling and/or iso kinetic sampling calculations/design.

Hoping someone has D1066 and can chime in as to whether it holds any info re high pressure HC work.

 

[KevinNZ]

As LittleInch said you will not get a representative sample unless the phases are evenly disturbed across the pipe area. This very unlikely.

This problem also for geothermal two phase lines with steam and water. The only method that seems to work is chemical tracer injection and sampling, to work out the phases and flow.

 

[Tuckabag]

I agree with you Kevin re obtaining a representative sample in a 2 phase, multi-component hydrocarbon stream, very difficult to do, if not impossible.
However if I can design a system in accordance with a particular standard for isokinetic sampling (which is what the client is asking us to do) then we will have covered off our responsibilities on the project.
Whether the system provides any meaningful information is another question altogether. I guess if you have a 2 phase stream and need to have some form of compositional analysis being performed, an isokinetic sample probe/sample conditioning system is going to give you the best chance of getting pretty close to representative.