3 replies to this topic

[bmont]

where can I get densities of methane at 25 bar and 1000K?

[ankur2061]

where can I get densities of methane at 25 bar and 1000K?

bmont,

The density at the 25 bar isobar at some values of temperature are as below:

500K - 9.648 kg/m3
520K - 9.266 kg/m3
540K - 8.914 kg/m3
560K - 8.588 kg/m3
580K - 8.286 kg/m3
600K - 8.005 kg/m3

I don't think extrapolating upto 1000K will work.

The above values are from:

"Thermpophysical Properties of Fluids. II. Methane, Ethane, Propane, IsoButane & Normal Butane" by B. A. Younglove & J.F. Ely of Thermophysics Division, National Engineering Laboratory, National Bureau of Standards, Boulder, Colorado 80303.

Hope this helps.

Regards,
Ankur.

[kkala]

where can I get densities of methane at 25 bar and 1000K?

You can use the corresponding states theory. Critican conditions for CH4 are 190.564 0K & 45.9 Bara (Zc=0.286). So Pr=0.545 & Tr=5.25, which give about Z=1.0 in a Compressibility factor diagram (mine is from Hougen, Watson, Ragatz, 1955, Zc=0.27). So density under mentioned conditions ρ=(16.043/22.414)*(25/1.01325)*(273.15/1000)/1.0=4.8 kg/m3.
For 600 0K Z is found again about 1.0, so ρ=8.04 kg/m3, versus 8.005 kg/m3 reported by Ankur.
Actually corresponding states indicate that CH4 of 25 bara behaves as ideal gas at such high temperatures as 1000 oK.

[S.AHMAD]

where can I get densities of methane at 25 bar and 1000K?

You can use the corresponding states theory. Critican conditions for CH4 are 190.564 0K & 45.9 Bara (Zc=0.286). So Pr=0.545 & Tr=5.25, which give about Z=1.0 in a Compressibility factor diagram (mine is from Hougen, Watson, Ragatz, 1955, Zc=0.27). So density under mentioned conditions ρ=(16.043/22.414)*(25/1.01325)*(273.15/1000)/1.0=4.8 kg/m3.
For 600 0K Z is found again about 1.0, so ρ=8.04 kg/m3, versus 8.005 kg/m3 reported by Ankur.
Actually corresponding states indicate that CH4 of 25 bara behaves as ideal gas at such high temperatures as 1000 oK.

I run PRO-II simulation using PR EOS, the answer is 4.795 kg/m3 which is very close to the one mentioned above