2 replies to this topic

[AhmadJAQF]

Hello,

 

We have a unit consist of C3/C4 splitter for LPG after it have been treated as sour LPG to sweet LPG, the issue is as much as we raise the top pressure we still loss C4 with the Overhead off gases can someone recommend a troubleshooting or any valuable comment to overcome of this problem. our splitter condition as below:

 

Top P = 19.1 Barg

Bottom T = 96 Deg C

Tray T#24 = 84 Deg C

Feed inlet = 22 m3/h

reflux flow = 11 m3/h

OVHD T = 48 Deg C

 

Our reflux/feed ratio as design should be 89%, we are far below that ratio where this is limiting us for more increment in the top P, The splitter consist of 30 tray , while feed is introduced in tray# 19 & 22.

[Bobby Strain]

If you don't have a licensed process simulator, get a free one from the web. ChemSep works well. Then explore.

 

Bobby

Edited by Bobby Strain, 16 August 2017 - 02:38 PM.

[colt16]

Hello,

 

We have a unit consist of C3/C4 splitter for LPG after it have been treated as sour LPG to sweet LPG, the issue is as much as we raise the top pressure we still loss C4 with the Overhead off gases can someone recommend a troubleshooting or any valuable comment to overcome of this problem. our splitter condition as below:

 

Top P = 19.1 Barg

Bottom T = 96 Deg C

Tray T#24 = 84 Deg C

Feed inlet = 22 m3/h

reflux flow = 11 m3/h

OVHD T = 48 Deg C

 

Our reflux/feed ratio as design should be 89%, we are far below that ratio where this is limiting us for more increment in the top P, The splitter consist of 30 tray , while feed is introduced in tray# 19 & 22.

 

You probably should not be raising pressure. Raising pressure in a column requires even more reflux and reboiling duty for the same separation and it looks like that is a bad choice in this situation. Lower the pressure back to design and try increasing reflux to the design condition flow.

 

Also, what is your feed composition and has it changed from design?