3 replies to this topic

[Vegeta]

Team, 

 

I am simulating a propane stream in the NGL plant and I have the following question: 

 

How does Aspen HYSYS calculate the standard liquid volumetric rate of the low boiling point liquids i.e. at what temperature and pressure? 

 

I have been using Aspen HYSYS for more than 3 years and I'm used to reference the standard liquid volume to 60 °F and atmospheric pressure.  However, this has been my first time to deal with low boiling point liquids. The liquid propane boils at -44 °F at an atmospheric pressure.  So, it shall be vapor at 60 °F.  The HYSYS results are not inline with this as follows (as an example): 

 

Mass flow rate = 102175 lb/h

Density at -44 °F (and 30 psig) = 36.4 lb/ft3

Actual volumetric rate at -44 °F (and 30 psig) = 2807 ft3/h

the standard volumetric rate of the same stream by HYSYS = 3211 ft3/h

This corresponds to a density = ~31.8 lb/ft

 

However, there is no way the stream is liquid at 60 °F and atmospheric pressure.  Am I missing something here? 

 

Your help is appreciated...

 

 

Regards, 

 

 

 

[Bobby Strain]

You need to find the definition for standard liquid volume. It's not the same condition as gas volume at STP.

 

Bobby

[breizh]

http://users.rowan.e...ty packages.pdf

Hi, 

Consider this resource to support your work .

Good luck

Breizh 

[Vegeta]

Thanks Bobby and Breizh...

 

The answer is in the pages 55 to 59. 

 

 

Regards,