Oxygen Liquid Density 1

[martin15]

Could someone please help with the folowing;
How do you calculate Liquid Oxygen Density at 10bar abs? For gas density calculations I use the Ideal gas law PV=nRT.
In the case of liquid, the temperature will not change in the liquid phase, only the pressure will change.

 

[25362]

You could use the data published in:

http://webbook.nist.gov/cgi/fluid.cgi?ID=C7782447&Action=Page

 

[TrentFGuidry]

The best approach depends on the details of the problem you are working on, but here are some options.

Values for molar volume can easily be turned into densities. Molar volume is the volume occupied by a mole, V/n. Density is the mass per volume m/V. Mass is the number of moles times the molecular weight, m=Mw n. Rearranging gives density equals molecular weight divided by the molar volume.

Tabulated experimental data is usually the most accurate way of predicting pure molar volumes or densities, but you need to have or acquire the experimental data, which in some cases can be a problem.

There are also correlations for saturated liquid volumes and for compressed liquid volumes. Using these two together, you can calculate the molar volume or density. For example, if you want the molar volume at a given temperature and pressure where the liquid is at a greater than saturation pressure, then you can calculate the saturation molar volume using one correlation and then compress it using the compression correlation.

For saturated liquid volumes, there is the Rackett correlation, which is Vs=Vc * ( Zc ^ (1- T/Tc)^ 2/7) , where Vs is the saturated liquid volume, Vc is the liquid critical volume, Zc is the critical compressibility, T is the temperature, and Tc is the critical temperature. There are other correlations that can be found in places such as The Properties of Gases and Liquids by Prausnitz et all.

If the actual pressures of interests are greater than the saturation pressure, then the saturated liquid volume should probably then be corrected for compression. There are correlations for that too, such as the Dymond and Malhotra correlation V-Vs=-C ln((B+P)/(B+Ps)), where Vs is the saturation volume, Ps is the saturation pressure, and B and C are parameters regressed to experimental data. There are also other correlations that can be found in places such as The Properties of Gases and Liquids.

Another option, which is usually less accurate than the above methods, but which sometimes gives OKish answers for some chemicals, especially simple non polar ones, is to use an equation of state such as the Soave Redlich Kwong or Peng Robinson. The PR equation usually gives better liquid volumes than the SRK.

Trent F Guidry