×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

Pressure control with flooded condensers

Pressure control with flooded condensers

Pressure control with flooded condensers

(OP)
Our depropanizer has flooded condensers.  Over the years we have tried to improve the pressure conrol in this tower without success.  The last proposed control scheme will control the accumulator pressure with the level in the drum.  That is, when the pressure increases, the overhead release will increase which will lower the accumulator level to expose more surface area in the ovh condensers.  When the pressure decreases, less will be released which will increase the level in the accumulator, to reduce the surface area in the overhead condensers.  Is this effective?  Can I control the tower overhead temperature with this configuration?  Will I ever overflow or empty the accumulator drum completely?    

RE: Pressure control with flooded condensers


The accumulator vessel should be filled with liquid all the time; the only thing that changes is liquid level in the upstream condenser. If liquid level shows in the accumulator, that means you're lacking of condensing capacity and therefore gas must be vented off from the reflux (accumulator) drum.

This control scheme is appliable only in systems with no noncondensibles in the overhead gas. As compared to other schemes it's the most effective and reliable, but requires total overhead condensation possibility. If you have C1 or C2 in the overhead product, it presents bad pressure control solution.

Hope this helps.
MaNaTMoS

RE: Pressure control with flooded condensers

I know of two books by F.G. Shinskey: DISTILLATION CONTROL for Productivity and Energy Conservation, and Process Control Systems, both edited by Mc-Graw Hill, which are good reading material for precisely this case.

RE: Pressure control with flooded condensers

Once the condenser if drained, it won't matter what happens in the accumulator.  Draining the accumulator increases deadband and slows response if the tower pressure drops.

Draining the drum can be used to drop pressure by venting vapor and non-condensables to a fuel gas / vent system.

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! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close