5 replies to this topic

Hi Guys,

1. When your feed pressure is below the column pressure, you get the HYSYS message "column feed stream entering the tower below stage P". It seems to converge, but what is the actual implication of this comment. Should your feed pressure always be higher than the column pressure.

2. Also is there away on HYSYS to get physical property data (density, surface tension) on a particular tray?

Thanks.

[Srikrishna Chaitanya]

Hi VC007,

If column pressure is greater than Feed pressure how your feed can enter the column ?( in reality always flow is caused by pressure drop , in other words fluid flows from high P TO low P ), In hysys it may converge some times when that pressure difference is not so high.In actual case column will have a pressure profile with High P in reboiler and low p in condenser , on each tray there is a different pressure , at least on the feed tray the pressure must be less than pressure of the feed entering .
yes there is a way to get physical properties on each tray , once your coulmn is converged open column/go to performance tab / transport propeties/view table (column tray range = ALL)
HOPE THIS HELPS


Regards ,

Satish

Thanks Satish, appreciate the quick feedback. Yeh that is what I figured, essentially there would be reverse flow due to the pressure difference.

I couldn't find the transport/view table bit under performance in HYSYS. I'm running the 2006 version of HYSYS.

[shan]

Thanks Satish, appreciate the quick feedback. Yeh that is what I figured, essentially there would be reverse flow due to the pressure difference.

I couldn't find the transport/view table bit under performance in HYSYS. I'm running the 2006 version of HYSYS.

At the column enviromental, you may select "Flowsheet" from down tab,"Internal Streams" from left panel, "Add" from right panel to specify any tray stream as a regulare stream to get all the properties that you want.

Thanks Satish, appreciate the quick feedback. Yeh that is what I figured, essentially there would be reverse flow due to the pressure difference.

I couldn't find the transport/view table bit under performance in HYSYS. I'm running the 2006 version of HYSYS.

At the column enviromental, you may select "Flowsheet" from down tab,"Internal Streams" from left panel, "Add" from right panel to specify any tray stream as a regulare stream to get all the properties that you want.

Thanks, I could have swore I checked all those tabs. :S

[Padmakar Katre]

Hi Guys,

1. When your feed pressure is below the column pressure, you get the HYSYS message "column feed stream entering the tower below stage P". It seems to converge, but what is the actual implication of this comment. Should your feed pressure always be higher than the column pressure.

Before to start doing simulation you first be cleared with your basic fundamentals of the process engineering. How the pressure levels are calculated at each point in an unit with Hydraulics. The pressure in the column inlet is always equals to the sum of the pressure preavailing on that tray + the DP of the inlet nozzle. I hope this is clear to you.

2. Also is there away on HYSYS to get physical property data (density, surface tension) on a particular tray?

Thanks.

Follow what Mr. Satish has suggested i.e. coulmn window- Performance Tab and you can get all the data there like V-L traffic along with the T,P and transport properties. I will recommend you to go through a document called HysysOpsGuide (Hysys Operations Guide)

Good Luck