## Featured Articles

Check out the latest featured articles.

## New Article

Product Viscosity vs. Shear

## Featured File

Vertical Tank Selection

## New Blog Entry

Low Flow in Pipes- posted in Ankur's blog

0

# Line Sizing With A Control Valve In Line

line sizing pr. drop calculation control valve

3 replies to this topic
|

### #1 james.corrobro@gmail.com

james.corrobro@gmail.com

Veteran Member

• Members
• 48 posts

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)

### #2 breizh

breizh

Gold Member

• 6,385 posts

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

fallah

Gold Member

• ChE Plus Subscriber
• 4,967 posts

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)

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

Chemitofreak

Gold Member

• Members
• 291 posts

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