Sucrose integration into COCO

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

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Re: Sucrose integration into COCO

Postby jasper » 10 July 2014, 10:50

The diagonal elements of the matrix do not apply to the Margules model; if you are using the Margules model you cannot enter A11 and A22.
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Re: Sucrose integration into COCO

Postby Farhan » 10 July 2014, 16:03

I have calculated values of A12 and A21 considerig 1st and 2nd and then 3rd and 4th effects. its values are too high and does not satisfy the log fugacity coefficient. Please have a look at the attached simulation. Is it sufficient to restrict the ''Psat'' equation to, Psat = exp(A + B/T + ClnT) . Because complete form of the equation gives quite a high value.
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Re: Sucrose integration into COCO

Postby jasper » 11 July 2014, 08:03

In attached you can see that the water vapor pressure is fine, compared to 5 sources at NIST. As explained, you will not want to affect the phase equilibrium by changing the vapor pressure. The vapor pressure needs to describe properly pure water. And it does.

I also suggested that you turn to a simpler model, where Poynting factor and saturated vapor fugacity are ignored, as this simplifies the fit. This is the DECHEMA model for fugacity caclculations. You did not turn this on.

Furthermore, in attached you can see that reasonable values for A are:

A_water_sucrose 0.572640655
A_sucrose_water 3.190734798

This is not such a difficult exercise and I have the feeling I am doing your homework. You came up with values of

A_water_sucrose 119371138
A_sucrose_water 28035002

And then conclude that it does not work well. Have a look at the parity plot in the attached Excel if you use your suggested values.

While you are at it, also have a look at values of zero for both values of A, this would represent an ideal mixture. Then you see why that option did not work well.

Please properly look at the formulas before asking me to do your homework.
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Re: Sucrose integration into COCO

Postby jasper » 11 July 2014, 09:35

It seems that the upload was incomplete. Attached again to this mail.
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