Jump to content



Featured Articles

Check out the latest featured articles.

File Library

Check out the latest downloads available in the File Library.

New Article

Product Viscosity vs. Shear

Featured File

Vertical Tank Selection

New Blog Entry

Low Flow in Pipes- posted in Ankur's blog

Hysys Convergence

hysys recycle convergence liquefaction hydrogen claude cylce

This topic has been archived. This means that you cannot reply to this topic.
11 replies to this topic
Share this topic:
| More

#1 hamed2020

hamed2020

    Brand New Member

  • Members
  • 9 posts

Posted 26 May 2016 - 01:44 PM

Hello everybody

I had simulated a simple Claude cycle for liquefaction of Hydrogen but unfortunately after completing the cycle I could not change the Feed conditions or other important parameter of cycle. In the case of changing parameters or Feed conditions I will face with the below mentioned error:

An Invalid math operation has occurred.

Insensitive error in HE

Error of consistency

I will attached my PFD and simulation file which is made in Hysys V7.2. If anyone know the problem please help me through this forum or my email: hamedrezaie20@yahoo.com

Attached File  HYSYS-Print.pdf   12.67KB   77 downloadsAttached File  complete simple claud.zip   69.73KB   43 downloads

Thanks to all

 



#2 Bobby Strain

Bobby Strain

    Gold Member

  • Members
  • 3,529 posts

Posted 26 May 2016 - 04:46 PM

Your simulation appears to have too many recycle operations. Analyze the process more thoroughly and determine where such operations should be used. And, you might need to add a controller operation somewhere. I am surprised that this simulation even ran.

 

Bobby



#3 hamed2020

hamed2020

    Brand New Member

  • Members
  • 9 posts

Posted 27 May 2016 - 01:49 PM

Your simulation appears to have too many recycle operations. Analyze the process more thoroughly and determine where such operations should be used. And, you might need to add a controller operation somewhere. I am surprised that this simulation even ran.

 

Bobby

Thanks dear Bobby

I am a new comer to Hysys and this forum could you describe more, even I do not know what is controller operation?

Hamed



#4 Bobby Strain

Bobby Strain

    Gold Member

  • Members
  • 3,529 posts

Posted 27 May 2016 - 03:36 PM

Keep RCY-5. Move RCY-3 to stream 14. Remove the other recycles. You can then adjust the split of TEE-100 until you get a converged solution. Then study how to use the ADJUST operation to do this for you. This might work. If not, study the flowsheet carefully and make sure enough streams are defined to obtain a solution.

 

And you need to boost the operating pressure considerably. I would start at 10 bar on the compressor discharge.


Edited by Bobby Strain, 27 May 2016 - 05:19 PM.


#5 Mahdi1980

Mahdi1980

    Gold Member

  • Members
  • 182 posts

Posted 28 May 2016 - 08:52 AM

Hamed,

 

I have not checked your simulation file. However, it is clear that you have applied too many Recycle streams. As Bobby said, you should delete some excess Recycles. My suggestion is that you may omit the Recycles 4, 3, and 2 to simplify the simulation.

After running, if you intend to change the composition or other parameters please note that you should make changes on the correct side of the Recycle.

Let me know the result

 

Mahdi



#6 hamed2020

hamed2020

    Brand New Member

  • Members
  • 9 posts

Posted 31 May 2016 - 01:06 PM

Hamed,

 

I have not checked your simulation file. However, it is clear that you have applied too many Recycle streams. As Bobby said, you should delete some excess Recycles. My suggestion is that you may omit the Recycles 4, 3, and 2 to simplify the simulation.

After running, if you intend to change the composition or other parameters please note that you should make changes on the correct side of the Recycle.

Let me know the result

 

Mahdi

I tried to do as you and Mr Bobby mentioned but I was not able to converge the Cycle with to Recycle but I try more to do that. Thanks alot.



#7 hamed2020

hamed2020

    Brand New Member

  • Members
  • 9 posts

Posted 08 June 2016 - 07:55 AM

Hamed,

 

I have not checked your simulation file. However, it is clear that you have applied too many Recycle streams. As Bobby said, you should delete some excess Recycles. My suggestion is that you may omit the Recycles 4, 3, and 2 to simplify the simulation.

After running, if you intend to change the composition or other parameters please note that you should make changes on the correct side of the Recycle.

Let me know the result

 

Mahdi

Hi Dear Mahdi

I did as you mentioned and run the cycle with 2 Recycle but unfortunately it acts the same as before and with altering any parameter such as mass flow of feed or portion of each stream at TEE the consistency error will be appeared and the Cycle will not be converged.

I have attached the PFD to this reply.

Thanks to you

Hamed

Attached Files



#8 Bobby Strain

Bobby Strain

    Gold Member

  • Members
  • 3,529 posts

Posted 08 June 2016 - 09:00 AM

I mentioned pressure before. You still need to fix that, too. And you need to adjust the splitter to make it work. And liquid normally comes from the bottom of a separator. You should pay attention to such things.

 

Bobby


Edited by Bobby Strain, 09 June 2016 - 02:17 PM.


#9 hamed2020

hamed2020

    Brand New Member

  • Members
  • 9 posts

Posted 10 June 2016 - 06:08 AM

I mentioned pressure before. You still need to fix that, too. And you need to adjust the splitter to make it work. And liquid normally comes from the bottom of a separator. You should pay attention to such things.

 

Bobby

Dear Bobby I change the pressure many times and at the last model pressure at the output of compressor is 21 bar. Liquid comes out from the bottom of separator but the appearance of PFD I mirrored the separator about Y. I don't know where should I use adjus operation(between splitter and which set? based on which parameter?) please let me know in details.

Thank you

Hamed



#10 Bobby Strain

Bobby Strain

    Gold Member

  • Members
  • 3,529 posts

Posted 10 June 2016 - 08:52 AM

It's important that you display information properly. Bad habits seem to stick with you. That won't help you in your career. Change the split fractions with input and observe the result. Keep changing the pressure and observe the results.

 

Bobby



#11 hamed2020

hamed2020

    Brand New Member

  • Members
  • 9 posts

Posted 16 June 2016 - 07:46 AM

Hello

Fortunately I ran my cycle and I should give my spacial thanks to Dear Bobby and Mahdi. My final PFD is attached to this message. 

Attached Files



#12 Bobby Strain

Bobby Strain

    Gold Member

  • Members
  • 3,529 posts

Posted 16 June 2016 - 09:04 AM

But the separator is still upside down. Don't start bad habits while you are still in school!  It seems to me that if this converges, you could remove one of the recycle blocks. The two you have are  essentially in the same stream.






Similar Topics