Repeat Problem 8.61 using the Peng–Robinson equation of state. Use a value for the binary interaction parameter of 0.026.

Problem 8.61

Using the equation of state method, determine the equilibrium composition in the vapor phase and the system pressure of a mixture of methane (1) and n-pentane (2) with a liquid mole fraction of x1 = 0.2 at 60°C. Use the van der Waals equation of state to determine fugacity for both vapor and liquid phases. Iterate until |∑yi - 1| < 0.001.