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[CHEMSTRONG]

Dear All,

 

I have distillation column with product sumps and rebolier sumps.. Rebolier out stream goes from rebolier sump which is bottom tray of column which is chimney tray for collection of liquid,holdup and draw off from bottom tray.. This tray is tray no1 and tray numbering is bottom up... Product sump is usual sump for withdrawing product from column ... Boilup stream joins column into tray 1 which rebolier sump again...

 

So in hysys, what i did is

 

1) I configured chimney tray for reboiler sump with tray efficiency as 5 % and weeping factor of 1..

2) Product sump is configure separately as 2 phase separator with vapor recycle efficiecy set to 5 %..vapor from this sump goes back to column again..

 

3) when running in steady state , everything runs fine, but when shutdown of column, slowly all tray tempertaures came down to ambient , but only tray number 2 liquid temp is stuck there at 179 deg C..

 

I want to troubleshoot this...

 

please help me...