15 replies to this topic

[Fish]

Hi all,

I have got a specific doubt on the calculation of natural gas pipe diameter.

I have 10,000 m3 of natural gas flow at a pressure of 5 kg/cm2 coming at 15 deg C.

I want to calculate the volume of flow, number of moles & ultimately pipe diameter for the above mentioned flow. I have done my calculation which I think is not right & hence needs confirmation.

Plz help me in calculating this.

Thank you.

Regards,
Vishal

Attached Files

•  NG_calc_GAK.xls   22KB   89 downloads

Edited by Fish, 14 April 2012 - 07:21 AM.

[breizh]

You should post your calculation .

As you know PV = nRT


Breizh

[Shivshankar]

Vishal,

FLow= Velocity X Area

Density= Mass/Volume

Area = (3.14) (Diameter square)/4

Pressure X Volume= Number of moles X Gas constant X Temperature (PV = nRT)

If you know the concept of Hydraulic diameter and Reynolds Number, Kinematic Viscosity, Dynamic Viscosity and Bernoulis equation you can calculate it.

Else, attach your calculation work copy so that we will know where you are stuck.

Attached are some documents to help you.

Regards
Shivshankar

Attached Files

•  formula-sheet.pdf   117.73KB   103 downloads
•  overheads.pdf   660.63KB   89 downloads

[S.AHMAD]

1. Not very clear your request and required more information. Flow rate 10,000 m3 is it m3/h or you have in the gas in storage?
2. It is very helpful if you could attached your calculation so that we know what went wrong

[Shivshankar]

Hi Vishal,

Attached following aocument will help you.

Regards
Shivshankar

Attached Files

•  solving pipe diameter.pdf   130.11KB   72 downloads

[breizh]

http://www.pipeflowc...s.com/flowrate/

A good calculator !

Breizh

[Fish]

Hi Breizh,

Thank you for your reply.

Plz see my original posts for attached file.

Plz let me know where I've gone wrong.

your suggestion will be highly appreciated.

Vishal

[breizh]

Vishal ,

a few comments !

Flow rate I guess is expressed in m3/h

Why do you take account water in your calculation you are dealing with gas ?

density = Mw/V with V =Z*R*T/P (m3/mol) thus density is in kg/m3

Flow (m3/h) / Mol volume (m3/mol) = mol/h

velocity (m/s) = Flow (m3/h)/3600 /pipe area (m2)

Hope this helps

Breizh

[Art Montemayor]

Vishal ,

As Breizh has implied, you obviously don’t know what you are doing or you are not aware of the theory behind fluid flow. In order to calculate the required diameter for a pipe, you must first identify what flow rate you propose to put though it. Note that the correct term is flow RATE – not just a volume of gas. You fail to give the rate of flow in your post and in your calculations.

You also fail totally to identify a flow rate equation that applies to the calculation. You refer to the ideal gas law – which has nothing whatsoever to do with the flow of gas – but that is all.

You should first be reading and studying the material that Shivshankar was kind enough to furnish you. That is the basis of what you should be calculating on. You seem to have a classical case of compressible fluid flow, but you show no evidence that you know what you are dealing with.

In order for you to have a flow of any sort through your pipe, you must suffer a pressure drop. That is the basis for all fluid flow – compressible or uncompressible. Without a pressure drop there can be no flow of any fluid through a conduit. Yet you don’t even make mention of a pressure drop.

From what you have submitted, I am forced to judge that you require a total immersion in the theory of fluid flow – specifically compressible fluid flow, which is more difficult than uncompressible fluid flow. In my opinion, you have your work cut out for you if you are to understand and subsequently solve fluid flow problems. Good luck.

[breizh]

Vishal ,

I've attached a good paper dealing with natural gas and compressible flow .

it should help

Breizh

[Art Montemayor]

Breizh:

Excellent contribution to this thread - and to all eager and ambitious engineering students following this Forum. Your help and support in this Forum deserves the highest praise - especially from all the students who read this thread.

May your tribe increase.

[breizh]

Merci Mr Montemayor !



Breizh

[Fish]

Thanx for your judgement Mr. Montemayor.

But I am not in interest of the people who dont correct others but just feel happy of giving free lectures. Well, I did not post my problem for the kind of comments that you have posted. I agreed that I went wrong somewhere & hence needed some clarification. I was just hoping to get a rough idea of pipe diameter of natural gas line at the flow rate & pressure I mentioned. I myself was not aware of how much pressure drop will be there as We are newly commissioning natural gas in the plant & we are in a very preliminary stage. I very well know comp & incomp nature of fluids.

My sincere suggestion to you, If you do not have attributes to correct specifically, then plz do not comment with general & airy comments. That serves no good.

Thanks anyway.

Vishal

Edited by Fish, 13 April 2012 - 11:38 PM.

[Fish]

Thank you for your attachment & suggestions Mr. Breizh.

I shall refer to it & try correct myself. If I have any specific doubts I will come back to you.

Your help is highly appreciated.

Thank you so much.

With Best Regards,
Vishal

[Shivshankar]

Thanx for your judgement Mr. Montemayor.

But I am not in interest of the people who dont correct others but just feel happy of giving free lectures. Well, I did not post my problem for the kind of comments that you have posted. I agreed that I went wrong somewhere & hence needed some clarification. I was just hoping to get a rough idea of pipe diameter of natural gas line at the flow rate & pressure I mentioned. I myself was not aware of how much pressure drop will be there as We are newly commissioning natural gas in the plant & we are in a very preliminary stage. I very well know comp & incomp nature of fluids.

My sincere suggestion to you, If you do not have attributes to correct specifically, then plz do not comment with general & airy comments. That serves no good.

Thanks anyway.

Vishal

Vishal,

Can you let us know in this thread who gave you free lecture ?

If you come better prepare and with proper question. we will come to know where you stuck. If you going to put wrong units and if someone see your spreadsheet attached, no one will understand it properly, what you are trying to do.
If something is wrong here with above comments by me, please let me know.But i don't see someone gave you free lecture here. we are trying help you by putting useful documents for your help, by putting our precious time and if you are complaining in this forum, this is disappointing. first point finger to yourself, and then to others.You are upcoming engineer, so we are helping out in a best way.

Regards
Shivshankar

[Fish]

Hi shivshankar,

That comment was not for you. It was for someone else. I have mentioned the name there too.

Plz see clearly.

Regards,
vishal