2 replies to this topic

[Arun Balaji]

hi frens..

i work for a petroleum company.. presently am working on the optimization of our distillation column in terms of newer control configs..

i have planned to implement an control logic based on heat balance of the tower. i have calculated the heat to be removed from the incoming feed for facilitating proper seperation. But am a bit puzzled in calculating the flow rates for the circulating(pump arounds) and the cold refluxes. i have some method to calculate the cold reflux but let me know if there is any procedure in determining the pumpard flows.

regards..
AB

[chemsac2]

Pumparound rates are typically estimated from Packie curves. I am attaching typical curves with this post.

For details of calculation, you can refer to "Elements of petroleum processing", Jones, D.S.J., John Willey and Sons, 1995 edition.

Regards,

Attached Files

•  PA_Rate.JPG   82.04KB   144 downloads

[Chellani]

Basic purpose of pump-around is to remove heat which in turn reduces vapor loading in a particular section and hence reduces jet flooding. You’ve already mentioned that you’ve estimated total heat that needs to be removed, which actually needs to be removed by pump-around and condenser. If you don’t use pump-around, load on condenser would increase and a section of column would have higher vapor load which would require higher diameter or higher column pressure. So you have to decide the section in which you would like to reduce your vapor load and your duty requirement which could be done in any steady state simulator. Pump-around flow doesn’t affect separation (at least not directly). Pump-around flow (at the design stage) would depend on the heat exchanger design in the loop. You can manipulate the flow to satisfy your requirements in this loop.
I hope this would be helpful.