×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

CV request choke valve

CV request choke valve

CV request choke valve

(OP)
Hello at everyone,

I must to design a multiple orifice choke valve.
I have the following data at the maximum:

flow: 13500 MMSCFD
Inlet pressure: 1300 psig
Temperature: 200°F
Outlet pressure: 300 psig
Specific Gravity: 0,683
State of fluid: Vapor

How do I calculate the Cv request?
I tried in ISA 75.01 but I don't understand some parameters like xt and other.

I have confused ideas.
Someone help me please.

Thanks to all.

RE: CV request choke valve

Some standards only allow the pressure drop  across a valve to be 50% of the inlet pressure so you'd go from 1300 psig to 650 psig to 325 psig to 300 psig.  You could fudge and go 1300 to 600 to 300.

RE: CV request choke valve

as first step you need to verify the conditions for critical flow (which in ISA S75 depends from xt , the pressure differential ratio factor), assume a xt of 0.6 (which could be just a starting point) and see, if (as suggested by dcasto) you'll find that dp (critical) is well below your design value (1300-300=1000 psig) you can redefine the design conditions or adopt a different solution,
Paolo

a free software for control/relief valves
http://www.prode.com/en/valves.htm  

RE: CV request choke valve

Just to add that I assumed the choke valve as a constant pressure control valve (the flow through the hole -port- could be at critical condition)

RE: CV request choke valve

(OP)
Thank you all for the answers

Another question on this topic. I have to calculate the noise with IEC 60534-8-3. My problem is the jet diameter Dj.
If I have a cage with holes calculated as per the rules: I find Fd, valve style, with the formula dh/d0, knowing the number and size of holes? If it's a positive or adjustable choke which is the jet diameter? corresponds to the bean?

There is also a way to know the size of the bean without first passing through tests or CFD analysis?

Thanks

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources