Vacuum Column Overhead Design and Line sizing

[prochem]

Hi!

I have couple of questions regarding vacuum column overhead design:

1) How to calculate non-condensable gas for vacuum column overheads?

2) What is the criteria for sizing vacuum column overhead line?

I will really appreciate help on the questions above.

Prochem

 

[Chance17]

Question 1: See attached graph for vacuum air leak.
You also need to add any inerts normally in the process stream

Question 2. See attached table of velocity. The answer depends on level of vacuum.

 

[Chance17]

Now see attached information which did not upload in previous post.

 

[Chance17]

again

 

[CJKruger]

prochem + Yitbos, in vacuum units you have to add the gas formed due to cracking (in the heater) to the air leaking in.

Cilliers