Extractor

Moderator: jasper

Extractor

Postby thubelihle » 04 April 2018, 00:17

Hi. My extractor cannot converge. And also the original document used NRTL with parameters from ASPEN, how do l convert them to the COFE one. attached are both files.
Attachments
NRTL PARAMETERS.PNG
NRTL PARAMETERS.PNG (30.59 KiB) Viewed 16069 times
EXTRACTOR.fsd
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thubelihle
 
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Re: Extractor

Postby jasper » 04 April 2018, 05:42

Please verify the units of measure of the Aij NRTL parameters in Aspen Plus from the Aspen manual. It is not clear from the dialog.
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Re: Extractor

Postby thubelihle » 04 April 2018, 19:42

the other thing is l cant really change the light fraction, l guess that's the reason it does not converge. In this case l used UNIFAC as the model. thanks
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Re: Extractor

Postby jasper » 05 April 2018, 05:30

Please elaborate on "cannot change the light fraction"?
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Re: Extractor

Postby thubelihle » 05 April 2018, 17:24

For the bottom feed, l need to put a light fraction of 1 on the chemsep unit for an extractor to let the unit operation know its a bottom feed, but l try to modify this input it does allow me to, hence the flowsheet attached above does not converge. Thanks
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Re: Extractor

Postby hkooijman » 13 April 2018, 11:43

Indeed you cannot change the light liquid fraction while running the extractor inside COCO. You can when you run ChemSep standalone. Under certain circumstance this indeed may cause the LLX model to not converge. A quick workaround is to load the LL-eXtractor in the ChemSep GUI, press F12 to open the sep-file in text format, and try to locate the [Feeds] section and try to enter the light fraction there by hand. Save the file, use the reload option in the ChemSep GUI, and try to run again. We will address the issue in the next updating of ChemSep LITE.
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Re: Extractor

Postby thubelihle » 13 April 2018, 22:32

thank you it did work!
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