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


aspen simulation of coldbox

aspen simulation of coldbox

aspen simulation of coldbox

Hi. I have a question.
I am going to simulate a cryogenic plant using Aspen plus. Here is the problem:
1) In simulation of coldbox, there are lots of streams, and as you know, we encounter recycle streams and iteration calculation. How can we avoid this issue?

2) In ordinary simulation of coldboxes, we determine outlet temperature except for 1 stream. So when we change process condition of plant, how come Aspen change outlet temperature?

RE: aspen simulation of coldbox

You have to "clever" when setting up your recycles. Not referring to your specific issue i have attached a small sketch to illustrate a common "error". Often when you build your simulation you "go with the flow" and this will lead to more recycle loops than necessary. They must all converge and often they impact each other. Try to look at your case and see if you can reduce.

Best regards, Morten

RE: aspen simulation of coldbox

I should warn you, i dont work with Aspen+ but HYSYS. I just assume that the issue with recycle is more or less generic and that the solution is also...

With regards to 2) - all simulations is about reducing your number of free variable to 0 by specifying your boundary conditions - once you have achieved this all the rest are determined. So you will have to look at what you wish to specify and what you wish to get as result. Some software have limitation in what you can specify and then get results from. E.g. HYSYS if you have a pipe segment specifying both downstream pressure, temperature, composition and mass flow gives you a system that is defined but last time i checked HYSYS couldnt solve this (it requires some of the information upstream).

Best regards, Morten

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!


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