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Line Sizing With A Control Valve In Line

line sizing pr. drop calculation control valve

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#1 james.corrobro@gmail.com

james.corrobro@gmail.com

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Posted 07 May 2021 - 05:42 PM

I am doing line sizing where Gas is being sent from Equipment 1 (Separator) to Equipment 2 (Compressor)

I have a pressure control valve in b/w Eqpment 1 and 2

For line sizing, I have straight line length as 50 feet

I have two ball valves and a control valve (globe valve)

Eqment 1 pressure is 50 psig and control valve is sized for 5 psi pressure drop

Now for line sizing based on equivalent length should I consider the pressure control valve as a globe valve and take equivalent length? OR should I consider equivalent length and also add 5 psi to the overall pressure drop for calculation? What is the suitable approach for line sizing?

For calculating pr. Drop per 100 ft should the pr. Drop across control valve be considered (5 psi)

 

 

Attached File  pressure drop calc.jpg   22.33KB   6 downloads



#2 breizh

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Posted 07 May 2021 - 10:53 PM

hi,

equivalent length means you have to convert each piece of equipment in equivalent pipe length and add them to the physical length of pipe .

 

I don't thing this is a best method of calculation ( equivalent length) , not accurate.

 

Note : a few handy calculators are available in this forum (search engine) or in the website underneath or Katmar Software

CheCalc

 

Good luck

Breizh.


Edited by breizh, 09 May 2021 - 02:21 AM.


#3 fallah

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Posted 08 May 2021 - 12:56 AM

I am doing line sizing where Gas is being sent from Equipment 1 (Separator) to Equipment 2 (Compressor)

I have a pressure control valve in b/w Eqpment 1 and 2

For line sizing, I have straight line length as 50 feet

I have two ball valves and a control valve (globe valve)

Eqment 1 pressure is 50 psig and control valve is sized for 5 psi pressure drop

Now for line sizing based on equivalent length should I consider the pressure control valve as a globe valve and take equivalent length? OR should I consider equivalent length and also add 5 psi to the overall pressure drop for calculation? What is the suitable approach for line sizing?

For calculating pr. Drop per 100 ft should the pr. Drop across control valve be considered (5 psi)

 

 

attachicon.gif pressure drop calc.jpg

 

You should calculate the pressure drop for 50 ft straight line then add the 5 psi for control valve and estimated pressure drop for two ball valves.



#4 Chemitofreak

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Posted 08 May 2021 - 06:56 AM

You know the pressure at the source and the destination i.e. you know the pressure drop available for the piping + Fitting + Control valve

 

For good controllability of the control valve the minimum pressure drop (at max flow) should be considered as 0.3 bar (good engineering practice), you can check your company guidelines.   

 

Line loss should be calculated as follows:

 

Loss in the Pipe (Pipe + Fittings {Elbows, ON/OFF valves, Tee, expander/reducer}) + Loss in control valve

 

Revert in case of any query.

 

Regards






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