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114 Chapters

Table 3.3.3 Summary of Equations for Calculating the Dew-Point
Temperature_________________________________

Subscripts: Methane = 1, Propane = 2

Equilibrium Relations

Y2L.1D + Y2L.2D = 1 (3.3.24)

K 2,lD = y2V,lD'/y2L,lD (3.3.25)

K 2,2D = Y2V.2D' / Y2L.2D (3.3.26)

Thermodynamic Properties

K 2, 1D = f (T 2D ,P 2 ') (3.3.27)

K 2 , 2D =f(T 2D ,P 2 ') (3.3.28)

Variables

Y2L.1D - y2L,2D - T2D - K-2.1D - K2,2D

Degrees of Freedom

F = 5 - 5 = 0

To simplify the solution procedure, first, inspect the equations to determine
if some rearrangement of them will simplify their solution. Although this problem
requires solving equations for a two-component system, we will generalize the
solution for multicomponent systems.
Starting with Equations 3.3.1 and 3.3.2 in Table 3.3.1, the mole balance for
the i th component is

(3.3.29)
y u m, = y 2V)i m 2V + y 2U m 2L
The equilibrium relation for the i th component is

K 2 ,i=y 2V ,i/y 2 L,i (3.3.30)

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