Modeling diagram of CO2 phases

[PAndre73]

Hello,

I am looking for help to model the phase diagram (for CO2, for example) in a pressure, temperature diagram on Excel via REFPROP.

To do this, I would like to have the melting temperature and sublimation temperature information.

In the REFPROP documentation, the parameters are:

MELT-PT or MELT-TP (depending on inputs)
SUBL-PT or SUBL-TP (depending on the inputs)

I am looking to have the Sublimation and metl pressures depending on the temperature, so I have in column A: temperatures from -100 to + 35°C and in column B the following formula:

=REFPROP("MELT-PT";"carbon dioxide";"T";"SI";$A12+273.15)*1000

This formula shows me an error.

Can someone help me?

[nist-aharvey]

Others will have to advise whether your REFPROP call is OK, but if you need a workaround you could directly program the fairly simple literature correlations for CO2 melting and sublimation that were used in REFPROP, which are in this paper:
https://doi.org/10.1063/1.555991

We actually have recently developed a new EOS for CO2, along with slightly revised melting and sublimation curves. The report and corresponding REFPROP Fluid file are not yet available to the public, but I hope they will be within the next month.

[Matthew-Boyd]

The formulas for REFPROPdll would be (assuming you want kPa output):

=REFPROP("MELT-TP","carbon dioxide","T","SI",$A12+273.15)
=REFPROP("SUBL-TP","carbon dioxide","T","SI",$A12+273.15)

or

=REFPROP("P","carbon dioxide","TMELT","SI",$A12+273.15)*1000
=REFPROP("P","carbon dioxide","TSUBL","SI",$A12+273.15)*1000