11 replies to this topic

[hirengdesai]

Dear All,
I would like to seek opinion/feedback on the water draw off arrangement for the condensate stabilizer column. Please refer the attached sketch.
In the Condensate stabilizer column, water draw offs are routed to separate Side vessel (top entry); the decanted water is removed via LV-200 from bottom.
There is no liquid Hydrocarbon outlet provided. I am not sure whether this arrangement will work? I have seen few designs, where entry to side drum is from the middle, with HC routed back to column from top and water from bottom. Appreciate if someone can provide how this arrangement will function? Thanks in advance.

 

[hirengdesai]

Please find the sketch. 

[breizh]

No sketch!

Activate the more Reply options, click on Use Full editor, load your sketch and attach it.

Breizh

[hirengdesai]

apologies. Hope this time it will work. Please refer the attached sketch. Regards

 

Attached Files

•  Capture.PNG   582.91KB   0 downloads

[breizh]

Hi,

This is an existing unit; you should refer to the process book where the philosophy of the operation should be described. 

Why don't you talk to the operation manager/engineer/operators?

Interface is mentioned on the PID this means phases should settle in the pot. You have drain 3/4" and manual valves 2" around the pot, this may be a discontinuous way to drain the organic phase ? 

 

Check also the notes on the PID, you may find answers.

 

Good luck

Breizh

[hirengdesai]

Many thanks Breizh for your reply. Unfortunately, currently I  don't have access to process book /operation team as this reference was from old project. As you mentioned, this seems to be a dis-continous operation to drain the hydrocarbon phase. I will try to gather some more material on this time. Thanks again for help. Regards

[PingPong]

.....
There is no liquid Hydrocarbon outlet provided. I am not sure whether this arrangement will work? I have seen few designs, where entry to side drum is from the middle, with HC routed back to column from top and water from bottom. Appreciate if someone can provide how this arrangement will function? Thanks in advance.

 

Don't worry, it will work. If the interface level rises the HC is simply pushed back to the column, where it belongs.

There is no reason to withdraw HC from the drum (except during a shutdown of the unit when it is drained to CD).

The purpose of the drum is to allow HC droplets to rise from the water so that the water contains as little as possible HC when it leaves at the bottom via LV-200.

[hirengdesai]

Many thanks PingPong for your reply.

One question: "Does this mean that the inlet line to the side drum will always be full of liquid?"

Thanks again. 

[PingPong]

"Does this mean that the inlet line to the side drum will always be full of liquid?"

Yes. It is filled with HC liquid while water drops from the tray fall through it towards the side drum.

Therefore each drawoff line must free draining, without pockets, towards the drum, which is probably what 'NOTE 3' is about.

 

I would expect that the three trays with water drawoff all have an inlet pan below the downcomer from where the water is drained. It is not indicated as such on the P&ID, but P&IDs are not always detailed enough for that kind of info which you better verify on the column and tray drawings. If the three trays don't have drawoff pans then the design is rather poor.

Edited by PingPong, 24 August 2026 - 03:47 AM.

[hirengdesai]

Many thanks PingPong.

I could find more data on this that I am attaching herewith;  i.e. sketches of side separator and draw off tray ( along with original sketch) if it helps.

 

Also Notes on PID:

 

Note 3. Vertical piping length of 3000 mm minimum immediately downstream column nozzle prior to any horizontal run of pipe fitting (Tee, Reducer, etc.)

Note 10: LV 200 opens at 900 mm and closes at 500 mm.

Note 11: LI 00 to be adjacent to globe valve.

 

 

Thanks again for your valuable inputs. 

 

Regards

Attached Files

•  Sketches.docx   119.02KB   2 downloads
•  Capture.PNG   582.91KB   0 downloads

[PingPong]

According to the column sketch trays 21, 20 & 19 all have draw-off pots, so that is OK.

 

I doubt however that the draw-off pot of tray 21 will collect any water as it is located directly under the reflux entry.

Surely the reflux does not contain free water as that should already have been separated in the reflux drum.

[hirengdesai]

Thanks PingPong and Breizh for your valuable comments.