This program can be used to calculate compressibility factor for a gas mixture. Additional parameters can be provided and the Panhandle Formula which calculates volumetric flow-rate.

Example of this program being used to show how volumetric flow-rate through a pipe decreases with increasing richness of gas.

Here are your compounds' formulae and names:
No. Formula  Name

----------------------------------------
  1 CH4      methane
  2 C2H6     ethane
  3 C3H8     propane

This is a gas that is composed mostly of methane (light gas).

>> zfactor([.7 .2 1],20684.2,672,20684.2,2068.42,5,10)
Tr =    1.6102
Pr =    4.4454
accentricity =    0.0428
Zfactor =    0.8394
Z =    0.6992
G =  814.2227
Q =   1.4466e+08

This is a gas that is composed mostly of propane (rich gas).

 >> zfactor([.1 .2 7],20684.2,672,20684.2,2068.42,5,10)
Tr =    1.1006
Pr =    4.6770
accentricity =    0.1280
Zfactor =    0.6475
Z =   -0.1724
G =   1.4471e+03
Q =   1.2406e+08

As can be seen the volumetric flow-rate, Q, decreases for the richer gas.