19 replies to this topic

[Nazia]

Hi Forum members, I am a process engineer. I previously worked on various simulation software but now I am trying to learn aspen hysys online by myself.   Capture1.JPG   57.86KB   12 downloadsI am doing an industrial case study and facing following problem. Please guide me to resolve this issue or suggest me any online institution to improve my skills.

Problem:

I am doing an industrial case study but there is something wrong: the stream “NATURAL GAS” doesn’t converge, I mean, it keeps YELLOW and there is a warning saying that there is “UNKNOWN FLOW RATE”. How is it possible if the molar flow rate is given (5000 kg-mole/hr) and the properties are set (T = 20°C and P= 24 bar). Seems to me that Natural Gas cannot be defined at these conditions. Is it right? If this properties are wrong (YELLOW line) I can’t go further? Please give me some advice. Screen shot is attached for reference.

[Liza Admani]

I think you should attend some online training to get the basic concept of aspen hysys. Could you please confirm me which fluid package you are using?

[processengbd]

you can attend one course for free

https://m.facebook.c...409713365976382

[jewel10]

can you provide more information about this data please.

 

[Nazia]

Dear Mr. processengbd

Thank u for your suggestion but i have already attend many live webinars from Aspen tech but these webinars are not useful for me to grow up my skills but i am interested in Instructor lead course (1 of 1 session).

[Freelance Process Engineer]

Regarding your problem could you please share some more screen shots like the composition and parameter of “Natural Gas Stream”. I personally found this site very useful for aspen relevant training. Some useful aspen training courses available visit: www.omesol.com - Aspen Hysys Basic - Aspen Hysys Advance - Diploma In Process Simulation - Aspen Hysys Dynamic - Flarenet - HTFS – Pipesys.

[Neelakantan]

1) if it is for training, just add the simulation file;

2) per your screen shot, with a feed stream and two product streams, all streams seem to have been calculated;

3) add a screen shot of stream properties

 

best of luck

neelakantan

 

PS: what is the temperature of the stream 5 in the snapshot? 4590 deg F?!!!!!

Edited by Neelakantan, 09 June 2014 - 09:58 AM.

[RockDock]

Well, not to sound too obvious, but is the composition defined? At those conditions, 100% C1 should allow a calculation.

[Bobby Strain]

The snapshot you show looks to be a converged solution. So, what's the problem? Natural gas is the specified stream it seems. So you only need to specify the stream: composition, flow, temperature, and pressure. Or some other combination of variables. You should have 4 degrees of freedom to complete the specification.

 

Bobby

[Nazia]

Dear forum members,

 

sorry for incomplete information, The fluid package is “ Peng Robinson” , please find below the more details about composition of stream.

 

Attached Files

•  Capture2.JPG   64.59KB   11 downloads
•  Capture3.JPG   60.25KB   9 downloads
•  Capture1.JPG   57.86KB   9 downloads

Edited by Nazia, 10 June 2014 - 12:37 AM.

[jewel10]

Composition and parameters are fine, this situation may be due to some software error. Is  it possible for you to reinstall your software. Furthermore, I think about the Natural Gas stream; no matter what set of conditions (Pressure and Temperature) you choose, the vapor fraction is always 0.5. It is strange as it should be liquid (fraction = 0), vapor (fraction - 1) and a mixture of phases (fraction 0 < x < 1).

[Neelakantan]

1) how c7+ is defined?

2) where is the steam summary for streams 5 and 6

regards

neelakantan

[Freelance Process Engineer]

Please let me know “C7+” is the hypo-component? Which you have defined in your simulation? 

[jewel10]

yes this may a problem , if there is a hypo component .

[Nazia]

Dear Forum members,

 

Yes C7+ is a hypo component, Further details please find the attached simulation of case study.  

Attached Files

•  case study.zip   37.94KB   55 downloads

[Freelance Process Engineer]

I have noticed that in your provided simulation. There is a hypo component "C7+", which is not properly defined due to which you are getting a warning "UNKNOWN FLOW RATE”.

To resolve this issue just go back to "simulation basis manager", select component tab then view the component list for Natural Gas Stream.

Click on hypo component. Open hypo component " C7+" and just click the estimate button at the bottom of that window.

Then go back to your simulation environment. Your Natural Gas stream will definitely converged after this. 

[Freelance Process Engineer]

I think you should get training from some online training institution like www.omesol.com , In order to improve you concept regarding the usage of Aspen Hysys software.

[Nazia]

Thank you members, the model has been converged, there was some information missing and I also forget to estimate the unknown properties. I have just added it in component list.

I have visited www.omesol.com and found this site very useful, I will definitely join www.omesol.com to get the professional training. Thank you members for your useful suggestions.

[Neelakantan]

before closing out, can you repost the "converged" solution snapshot?

 

regards

neelakantan

[Nazia]

Dear Mr. neelakantan

 

find below the snap shots and converged case study simulation.

Attached Files

•  CASE STUDY converged.zip   59.16KB   41 downloads
•  Capture 1.PNG   35.54KB   10 downloads
•  Capture2.PNG   32.52KB   7 downloads
•  Capture3.PNG   45.41KB   7 downloads