3 replies to this topic

[wnovaes]

Martin Sneesby,

Frist, thanks for the reply.

But, I tried the Aspen Plus Simulator and it has the DECHEMA within its library. However, the results of VLE calculations were not so good for middle and high concetration of Ethylene Oxyde in water.

Best Regards,
wnovaes

[Martin Sneesby]

Are you using an appropriate thermo package like NRTL? The DECHEMA database (and any others) is based on experimental data so should be reliable. However, this data still needs to be fitted to a thermodynamic model, and this can introduce errors itself. If the choice of thermo is inappropriate, the parameter fiiting won't work well.

You have indicated a mismatch at mid-high concentrations of EO - does this mean you have your own experimental data? If so, you can always fit your own VLE parameters with a tool like Aspen Plus.

If you are comparing your modoel with plant data, are you sure that your other assumptions are correct? Perhaps its not the EO-water VLE that is generating the mismatch, but the presence of some other components. Are you comncentration and temperaure measurements accurate? Etc.

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