×
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

Non-condensible in Reflux condenser.

Non-condensible in Reflux condenser.

Non-condensible in Reflux condenser.

(OP)
Hello,

I have a question regarding Operation of a Reflux condenser.

From a top of Distillation tower, the vapor condenses to liquid in a Reflux condenser.
In that case, Is there possibility to accumulate Non-condensibles due to leakage or the others in the Reflux condender?
If Non-condensibles are accumlated in the Reflux condenser, How to remove it?

And I have another question.
The condensate should be cooled to saturated condition.
How can it be controlled extactly?
Is there a good practice for the condensate to be kept being in Saturated condition?


Thank you in advance.


RE: Non-condensible in Reflux condenser.

Hi,
You should have a vent line on the shell connected to atmosphere or to your vacuum pump (if column working under vacuum) to release the non condensable stream .
Regarding the second question , it's based on the design of the condenser (duty) and coolant available . Temperature control of the condensate with action on the coolant flow .
My 2 cents
Pierre

RE: Non-condensible in Reflux condenser.

This is an old-old process problem ....

We need many more details... Can you include outine drawings of the Condenser and placement on your tower ?

What are the process conditions and maximum flow conditions and what cooling media are you using ?

What are the materials of construction of the HX ?

Pictures ????

MJCronin
Sr. Process Engineer

RE: Non-condensible in Reflux condenser.



As Pierrieck said,, you have a vent valve in the top line of the condenser if it can be released to the atm... You will see it, because the column pressure begin to increased slowly without any reason, I assume that is a total condenser.

Horacio

https://www.linkedin.com/company/lagotuy/

RE: Non-condensible in Reflux condenser.

(OP)
Dear MJ Cronin,

A Cooling media is water (temp. : 35 C).
The Vapor is steam.(Operating press. : 1 atm Abs)

The tubes of the exchanger are stainless steel.
Construction of the exchanger is as per TEMA std.
And, I am very sorry that I can't inform to you more details.

Thank you in advance.

RE: Non-condensible in Reflux condenser.

Quote (gotothesky)

The Vapor is steam.(Operating press. : 1 atm Abs)
You need a vacuum suction system (permanent or portable) to evacuate non-condensables from zones its accumulate. Are those inert or toxic/flammable?

For general information see para. 14.11 Lieberman's Process Equipment Malfunctions.

RE: Non-condensible in Reflux condenser.

(OP)
Dear shvet,

Thank you for your confirmation.

The non-condensible may be nitrogen, carbon dioxide, or methane.

But, I would like to mention this one!
I want to keep vacuum pressure in the distillation column only.
Is there an isolate valve or a system to keep vacuum condition for a column only?
The other systems that are connected to the disttillation column operate under atmosphere pressure.

And, I have another question.
If I adopt a new gas vacuum pump to remove non-condensates form a condenser, Can it work properly?
The vacuumed gases can move to a reactor as Recycle.
I think in this case that the gas vacuum pump may operate frequently according to Temperature changes of the condenser.

And, I have no book that you mentioned.
I am very sorry for not having it.

Thank you in advance.

RE: Non-condensible in Reflux condenser.

Quote (gotothesky)

I want to keep vacuum pressure in the distillation column only.
Is there an isolate valve or a system to keep vacuum condition for a column only?
The other systems that are connected to the disttillation column operate under atmosphere pressure.
Provide more information: P&ID + description. Process development would be better to leave to an experienced process engineer. Otherwise the designed system might be going to be inefficient or even unsafe for personnel or environment.
"That guy from the internet" is not a source to rely on.

Quote (gotothesky)

I want to keep vacuum pressure in the distillation column only.
If I adopt a new gas vacuum pump to remove non-condensates form a condenser, Can it work properly?
The vacuumed gases can move to a reactor as Recycle.
I think in this case that the gas vacuum pump may operate frequently according to Temperature changes of the condenser.
It can.
I am sure that trace amount of N2, CO2 and CH4 are not worth of spent sources.

Quote (gotothesky)

And, I have no book that you mentioned.
I am very sorry for not having it.
Try to search it in google.

RE: Non-condensible in Reflux condenser.

(OP)
Dear Shvet,

Thank you for your kind reply.
I am a engineer for Heat exchanger and pressure vessel.
My major is chemical engineering.
I can roughly understand process, but I need to know an actual practice for process arrangement.
I agree with your comment!

Now, I am developing a new system and my subject in this thread is related to this new system.
The development stage is under Performance Checking with Bench scale system.
Due to some difficulties, I can't proceed the development.
Now, I am look forward to find out a chance to proceed the develment.
I hope to find the chance out in the United States.
(I am a Korean.)
When I make a real scale of the system, I need a good process engineer who know well a good practice for process.

Thank you in advance.

RE: Non-condensible in Reflux condenser.

Pierre's reply earlier on basically said it all.

You cannot have a vacuum in the column only. Fluids flow from zones of (relatively) high pressure to zones of lower pressure. So the condenser must be at a lower pressure than the column if you want the gas to flow in that direction. Although you have a vacuum pump, most of the vacuum is generated by the condenser. I suppose you could theoretically put a compressor/blower in the gas line from the column to the condenser but that would be very expensive to operate.

If the column is operating under vacuum you can be certain that you have air in the condenser, and probably other non-condensables too. It is standard practice to vent from the cold end of the condenser shell to the vacuum system. You do not need a separate vacuum pump for the non-condensables - the entire function of the vacuum pump is to deal with the non-condensables.

BTW - if you have a reflux drum then you will need to vent there as well.

Katmar Software - AioFlo Pipe Hydraulics
http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

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


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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