Sucrose integration into COCO

[Farhan]

i am working on modelling of a sugar plant containing hybrid evaporators (in combination with membrane). I couldn't found Sucrose C12H22O11 in the component list. Can any one provide me the source file file for Sucrose in ''.pcd'' format or at least provide me the data required in PCD manager.

Regards;

Farhan
M.Sc Student
UET Peshawar, Pakistan

[jasper]

Sucrose is not an easy compound from a phase equilibrium point of view. Do you require accurate phase equilibria? Is sucrose going to be in solution, or in a solid phase? From your description I presume it will be in solution and you do not need a proper prediction for the vapor phase. So you will have to make a few assumptions I think.

You can use the PCD Manager to create a new PCD for sucrose, or you can start from an existing compound and change the properties directly in TEA. Some of the required properties are here: http://webbook.nist.gov/cgi/cbook.cgi?N ... e&Units=SI

If you are using an equation of state you will have to put in some dummy critical properties. If you are using an activity model you will have to put in some dummy vapor pressure (very low of course as you do not want sucrose in the vapor phase). TEA will tell you which other properties it needs.

If on the other hand you want sucrose to be only in the solid phase things get a lot easier, and you can model sucrose as a solid-only compound. Now all properties you need are on the above NIST page, except for density, which perhaps you can use from here http://homepages.gac.edu/~cellab/chpts/ ... le3-2.html or here http://en.wikipedia.org/wiki/Sucrose.

So the short answer is: it is not available in the pcd files that come with COCO, but you can create it yourself, if you make some assumptions and look up some properties.

[Farhan]

@Jasper: You are right i am dealing with Sucrose solution. i am having problem with finding following properties of Sucrose in order to put them in PCD manager.

Critical temperature, Critical pressure, Critical volume, Critical compressibility factor, Triple point pressure, Acentric factor, Radius of gyration, Solubility parameters
Dipole moment, Vander Waals volume, Vander walls area, SRK acentric factor, API-SRK s1, API-SRK s2, Mathias-Copeman C1, Mathias-Copeman C2, Mathias-Copeman C3
Chao-Seader acentric factor, Chao-Seader solubility parameter, Chao-Seader liquid volume, COSTLD characteristic volume, Lennard jones diameter, Lennard jones energy
Rackett parameter, Fuller e al diffusion volume, Parachor, Wilson volume, UNIQUAC r, UNIQUAC q, UNIQUAC q’

[jasper]

You do not necessarily need all of those. Which thermodynamic models are you using?

[Farhan]

Peng Robinson

[jasper]

Seems like an odd choice for this system.

You will need the critical properties and acentric factor, and possibly PR binary interaction coefficients. Perhaps more data depending on the models are you using for liquid volume, transport properties and surface tension.

Note sure what to advise you about critical properties, other than to reconsider and use an activity model instead. What else do you have in the solution?

[Farhan]

Sucrose and water solution

[Farhan]

What do you suggest if I use UNIQUAC ?

[jasper]

The groups you pick affect the fugacity of the compounds that are not sucrose to some extent, so pick something representative. If you have just water then I suppose it does not matter really. Pick an ideal vapor phase.

Make sure the vapor pressure for sucrose is really low, e.g. 1e-20. This forces the compound to be only in the liquid, essentially.

[Farhan]

I don't have idea how to define correlations in PCD manager. Please provide me literature.