NRTL parameters in COCO

[vieira_fequi]

Hello,

I'm trying to perform Biodiesel simulation in COCO and to do that i need to use NRTL model to the liquid phase. I have some doubts about the parameters to insert in "Property pack definition". I saw in Help the definition concerning "tau ij" which has the interaction parameters (gij-gii), (gji-gjj). Looking in the windown "interaction parameters" there are two possibilities of parameters, the "NRTL interaction" and " NRTL interaction temperature dependence", so, to me there is a divergency (or missing some equation in help) between the help definition about NRTL model and the input parameters in the "Property pack definition, Interaction parameter". Can you explain that?

Thanks,
Gonçalves

[jasper]

You are absolutely right that the documentation was unclear in this. The documentation has been updated (both online, and via CUP, COCO Update).

Note only that, but in case energy units were selected, the implementation was incorrect. This has now been corrected. In addition it is checked that if interaction parameters have a temperature dependence, the used units of measure are consistent. These updates are available via CUP.

[jasper]

(please note that this topic pertains to COCO and has been moved to the COCO board; this forum is more generally for any CAPE-OPEN related questions).

[jasper]

Note, the energy units were correctly implemented prior to last week's 'correction'. Last week's correction made that specification in energy units was incorrect. This has now been repaired. Fix available via COCO UPdate.

The documentation now reflects the actual situation:

Interaction parameters specified in temperature units are divided by temperature only.
Interaction parameters specified in energy units are divided by R * T.
Interaction parameters specified in energy independent units (dimensionless) are used as such.

http://cocosimulator.org/index_help.php ... tivity.htm

[sunny]

hello, i am trying to simulated methanol manufacturing process in coco simulator. I have encounterd a problem whille solving for Distillation column in thich Methanol separated from other gases. The interaction-parameters are unavailble. we are accounting other errors too. Please help me so we can solve this problems. awaitng for your positive response...

[jasper]

The last bit of the error message is the important part, and it is not shown. Can you perhaps post the output report of column_158?