Question 6.4.4: Bubble- and Dew-Point Calculations Using Txy Diagrams 1. Usi......
Bubble- and Dew-Point Calculations Using Txy Diagrams
1. Using the Txy diagram, estimate the bubble-point temperature and the equilibrium vapor composition associated with a 40 mole% benzene–60 mole% toluene liquid mixture at 1 atm. If the mixture is steadily vaporized until the remaining liquid contains 25% benzene, what is the final temperature?
2. Using the Txy diagram, estimate the dew-point temperature and the equilibrium liquid composition associated with a vapor mixture of benzene and toluene containing 40 mole% benzene at 1 atm. If condensation proceeds until the remaining vapor contains 60% benzene, what is the final temperature?
1. From Figure 6.4-1a, for x_{B} = 0.40, \boxed{T_{bp}≈ 95°C} and \boxed{ y_{B} ≈ 0.62} . (This matches the result of the much lengthier solution of the previous example.) When x_{B} = 0.25, \boxed{T_{bp}≈ 100°C} . The temperature thus rises by 5°C as the vaporization proceeds.
2. From Figure 6.4-1a, for y_{B} = 0.40, \boxed{T_{dp}≈ 102°C} and \boxed{x_{B} ≈ 0.20} . When y_{B} = 0.60, \boxed{T_{bp}≈ 96°C} .
Note: The precision associated with Txy and Pxy diagrams is less than that of numerical calculations, as reflected in this example by the use of the ≈ . However, the ease of following the process path makes the diagrams quite useful
