Liquid in gas pipe
Liquid in gas pipe
(OP)
Good Afternoon,
I have a question.
We have a pipe about 9km. We send gas inside this pipe.
I would like to know when we are going to have liquid. I know that we can use the Dew point.
Even if I know that we are going to have liquid is it possible to calculate the volume of liquid?
Thank you.
Best Regards.
I have a question.
We have a pipe about 9km. We send gas inside this pipe.
I would like to know when we are going to have liquid. I know that we can use the Dew point.
Even if I know that we are going to have liquid is it possible to calculate the volume of liquid?
Thank you.
Best Regards.





RE: Liquid in gas pipe
You might try Section 17 in GPSA for two-phase flow if you wanted to go through a lot of calculations manually.
Regards,
SNORGY.
RE: Liquid in gas pipe
In 9 km you can be very certain that you have a large number of sags and lowpoints. Every one will accumulate liquid. That liquid will support bacteria colony's (think MIC) and will absorb any available gases (think CO2 Mesa Attack). It may only be a few kg/day, but that number adds up quickly into real problems.
If your velocity is high enough (say around 3-4 m/s) then the smaller sags will generally get dried up by the sweep effect. Bigger sags will collect liquid even in very high velocity lines.
All of the pipeline models handle condensation and water accumulation as an average of averages. None of them is going to give you an answer that you can use. The multi-phase flow correlations are even coarser and of less value.
David
RE: Liquid in gas pipe
RE: Liquid in gas pipe
I would like to do it manually. I read Section 17 in GPSA.
I found the Flanigan Liquid Hold up correlation. For the calculation of the Liquid Hold up they just use the gas velocity.
I try to do the calculatio I found about 30 m3 of liquid in the pipe. It's strange because they don't need the temperature or even the density of gas to calculate the liquid hold up.
Best regards,
RE: Liquid in gas pipe
http:/
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Liquid in gas pipe
Back in the dim dark slide-rule days, a lot of effort went into developing correlations that the average Engineer (who was no smarter, no more motivated, and no less lazy than today's crop) could successfully solve more times than not. Some of the correlations stood up to a wide range of problems and others were applied far outside their applicable range (e.g., Turner did his vertical flow analysis at over 1,200 psig and I see people today doing the "Turner Calculation" with 10 psig wellhead pressure), but all were more or less slide-rule friendly.
Flannigan is not evil, users of it just need to do their homework to determine where it has a chance of success. You have to dig pretty deep to find out why it has the parameters it has.
David
RE: Liquid in gas pipe
RE: Liquid in gas pipe
For the program I was writing, I was trying to predict the effect of a flow-profile-modifying tool and in general terms was able to predict flow improvement in the range of plus/minus 30% which is better than flipping a coin. The client was happy and the results made their clients happy.
The starting assumption was that there was no liquid water at the head of the pipe, so the water cut was a function of the dew point and was in a range where Duckler and Flannigan were ok.
David
RE: Liquid in gas pipe
Actually I don't need an accurate value. That is why I wanted to do it manually.
I have never work on this kind subject. I would like to give some details about the situation.
The gas is coming from an MP separator and then go to the 9 km pipe. There is no liquid in the gas. But for me, I will be faced to liquid formation during gas transportation. I just wanted to know if the scrubber at the end is sufficient for the liquid formed. That is why I wanted to know the volume of liquid.
I really thank you. I learn a lot with your responses.
Best Regards,