CO2-Methane liquid vapor equilibrium data 1

[ctowles]

I am working on a natural gas chilling application.

I’m calculating the head load (cooling load). We need to bring the natural gas from 70 F down to 28 F (at 750 psig). The natural gas is 12% CO2, 5% Ethane, 82% Methane, 1% other (mole%). Pure CO2 will condense from vapor to liquid during this temperature change at this pressure. This greatly impacts the heat load for the chiller. I’m wondering though, since the CO2 is mixed with Methane, and at a relatively high pressure where the gases are not ideal (compressibility, Z, for this mixture is .84) that the intermolecular forces/mixing properties may prevent the CO2 to condense.

What I really need is a CO2-Methane binary mixture vapor- liquid equilibrium chart. I haven’t been successful in finding that. I was wondering if someone could shed a little light on this subject. Thank you.

 

[sshep]

This is my reliable source of mixture VLE data, but it costs a little. Seems like alot of data for CH4-CO2

http://i-systems.dechema.de/detherm

This is another site I have bookmarked but don't use much. It is free, has some data for this system, and might provide something useful

http://infosys.korea.ac.kr/kdb/index.html

best wishes,
sshep

 

[DickRussell]

I would think you would be using a process simulator, or at least a decent flash program for the calcs, involving an equation of state for that mixture at elevated pressure. The cost of a flash program could be less than that of a large collection of data, most of which you may not need. How are you doing the calculations?