Gas and Liquid in pipe 2

[oillio]

Good Afternoon !

I would like to know when we flow gas and liquid (oil + water) in a pipem, what are the things which we have to be aware except drop pressure, line integrity?

Thank you

 

[BigInch]

When fluid builds up and backs up gas pressure until it finally forces a slug smashing into the processing facilities, floods and knocks out your compressor.

**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch

http://virtualpipeline.spaces.live.com/

 

[oillio]

Thank you BigInch.

Does anyone have a software to do drop pressure calculation?

I tried to do it manually and the result are very strange. I used the example 17.4 done in "Fluid and Flow piping" Section 17
I found a drop pressure of 6900 Kpa which is strange cause the inlet pipe pressure is 650 Kpa. Maybe such calculation are fit for short line..cause I am working on 40 km pipe.

Thank you.

 

[BigInch]

You'd better get some good software for 2-phase flow in a 40 km line. Olga or PipeSim.

**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch

http://virtualpipeline.spaces.live.com/

 

[DrillerNic]

Or Pipeflo

Hand calculation of the pressure drop in a multiphase pipeline (as opposed to mutiphase piping) isn't really very practical.

 

[zdas04]

When I was working on my Masters (in multi-phase flow) I reviewed a large number of Master's and PhD theses on the subject. Everyone was doing CFD (computational fluid dynamics) and claiming amazing results. One paper stands out--the guy wrote up his model for over 300 pages before he put in "my results consistently matched measured data +/-70%". +/-70% is markedly worse than flipping a coin. The problem isn't that the guy is inept, the problem is that each flow correlation is assuming a steady state single flow regime (i.e., slug, annular, wavy, etc) and steady state in multiphase flow is non existent.

Flow regime will change many times per second and a correlation that works for wavy flow will not work for annular flow. The changes are random and happen on their own schedule. You can spend a bunch of money on OLGA or HYSIS or PipeSim or PipeFlo, etc. and you'll get numbers. You can then take those numbers to 9 decimal places and pretend they mean something--they don't.

It isn't hopeless, but you need to REALLY be certain about (1) what it is you are trying to do (will someone get hurt if you get it wrong?); and (2) what sort of reliability and repeatability do you expect. Typically you will have to lower you "accuracy" expectations dramatically.

David

 

[CJKruger]

oillio, I would of course recommend Korf Hydraulics for 2-phase flow, considering I am involved with it.

http://www.korf.co.uk.

 

[SJones]

You should also be aware of erosion-corrosion.

Steve Jones
Materials & Corrosion Engineer

http://www.oilandgaspeople.com/cv/11499664

http://www.linkedin.com/pub/8/83b/b04

 

[786392]

Beware of extensive turbulence always generated in such cases and highly eroding conditions are the usual outcome with only slight induction of any particulates from any source

I presume such sources to be abundantly available inside long process/petroleum pipelines&

especially if the gas and liquids are not controlled/ maintained 100% pure/clean

thus any contaminants could be finding their way into these main flow streams and erosion becomes inevitable in such heterogeneous flow conditions!

Moreover flow stream heterogeneousness also gives rise to static charges generation beyond/above usual consideration; possible creation of Ignition source(s) may result.

Best Regards
Qalander(Chem)