Question

Use the SRK equation of state to calculate the saturation pressure of etane at −

58.5 ◦C

Answer 1

The Soave-Redlich-Kwong single equation of state can accurately describe both the liquid and vapor phase. This Demonstration applies this equation of state to estimate several properties of ethane and plots isotherms for various values of the temperature varying from 274.15 K to 303.15 K. The liquid and gas molar volumes (in ) as well as the vapor pressure (in bar) of ethane at the selected temperature (in K) are obtained using the equal area rule (i.e., both shaded areas must be equal).

The Soave-Redlich-Kwong equation of state [1-3] is given by

,

where , ,

and .

Ethane’s critical temperature and pressure and acentric factor [2] are: , , and .