4 replies to this topic

[emma14778]

I am designing a vacuum distillation column with a chimney tray and a side product stream in a glycol/water vacuum distillation column. I would typically size the chimney tray to achieve a residence time of 3-4 minutes and sizing the risers to ensure reasonable pressure drop. The residence time of 3-4 minutes is chosen based on process control considerations.

 

The chimney tray is feeding a product pump and I am worried about carrying vapor into the pump. Are there any rules of thumb for ensure proper vapor disengagement on the chimney tray? 

 

Let me know if more information is required.

 

Thanks

 

Emma

[PingPong]

Are there any rules of thumb for ensure proper vapor disengagement on the chimney tray?

No.

 

Make a trap (step down) at the side of the chimney tray so that the top of the draw off nozzle is a half nozzle diameter below the floor of the chimney tray.

[breizh]

Hi,

Consider these resources :

https://www.slidesha...llation-columns

 

https://www.gtctech....-ptq-q2-gtc.pdf

 

 

Breizh 

Edited by breizh, 06 August 2020 - 01:14 AM.

[katmar]

In downcomer design a residence time of 5 to 7 seconds is generally regarded as sufficient to ensure adequate vapor disengagement. In my opinion, if you have a residence time of 3-4 minutes and you install an internal sump as described by PingPong you will have no problems at all.

[emma14778]

Thanks for the feedback everyone. Went with the 3-4 minute residence time and internal sump. No issues on startup.