fug question

Discusses use of COCO, the process simulation and modelling software suite from AmsterCHEM, downloadable from http://www.cocosimulator.org

Moderator: jasper

fug question

Postby aken » 31 December 2018, 05:33

hi. does the ChemSep distillation column use a rigorous method approach. l say so because l designed a column, went to FUG and obtained the number of stages and feed stage number, reflux ratio, bottoms flowrate. I then input these parameters back but the specified recover in FUG was not met. see attachment. regards
Attachments
SHORTCUT.fsd
(52.08 KiB) Downloaded 592 times
aken
 
Posts: 54
Joined: 18 December 2018, 06:02

Re: fug question

Postby hkooijman » 31 December 2018, 14:20

yes, ChemSep is performing a rigorous calculation using the PR equation of state. in your example the feed is put at the wrong place, you can tell this by the McCabe-Thiele plot (look up some text books on this if you need). By setting it to the middle (stage 75) will get you a much better separation with >99% purity with 150 stages. I then entered the Eduljee proposals from the FUG page, 118 stages (accepting the feed stage as 59) and a reflux ratio of 14.7. The products were 98.7% pure, close to the specified 99%. The difference may lie in the fact that in a rigorous calculation the relative volatility is not constant. However, I noticed that the Fenske feed stage indicated on the FUG page was 114, which is close to your original feed location. I suspect there may be a bug there, I will investigate.

Do realize that for close boiling components like these, you need accurate binary interaction parameters to get good answers. Also, this separation would normally be done at higher pressures to be able to run the condenser at temperatures > 45 deg C.

HK
hkooijman
 
Posts: 51
Joined: 13 April 2013, 23:50

Re: fug question

Postby hkooijman » 01 January 2019, 01:56

This bug has been fixed in v8.11 which will be released in January 2019

HK
hkooijman
 
Posts: 51
Joined: 13 April 2013, 23:50

Re: fug question

Postby aken » 02 January 2019, 07:16

hi, ok thank you.



regards
Akan
aken
 
Posts: 54
Joined: 18 December 2018, 06:02


Return to COCO (AmsterCHEM)

Who is online

Users browsing this forum: No registered users and 3 guests

cron