Exercise 02 Solution ENG

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Assignment #2: Results 1. Bubble- and dew-point calculations  Bubble-point pressure (Pb) at T = 53.5 °C: 2 1 ()b i i i P x P T     Pb = 0.7002 bar.  Dew-point pressure (Pd) at T = 53.5 °C: 2 1 1 () d i i i P y PT     Pd = 0.6940 bar.  Bubble-point temperature (Tb) at P = 1 bar: 2 1 ( ) ( ) 0b i i b i f T x P T P        Tb = 62.96 °C.  Dew-point temperature (Td) at P = 1 bar: 2 1 11( ) 0 () d i i id fT y P PT       Td = 63.05 °C. 2. Multicomponent vapor-liquid equilibrium (VLE) Figure 1. System layout. F, zFi D-101 V-101 C-101 L’, xi’ E-101 D-102 V, yi L, xi V’, yi’ A B  Flow rate and composition of the streams coming out from the first flash-drum D-101 From the specified vaporization ratio α1 = V’/F and assuming F = 1 [kmol/h], it follows that: V’ = 0.25 [kmol/h] L’ = 0.75 [kmol/h] By solving the Rachford-Rice equation: 101 101 1 1 101 ( ( ) 1)( ) 0 1 ( ( ) 1) Nc Fi i D D i iD z k TfT kT         the operating temperature of the first flash -drum (D-101) is obtained (344.90 K) and the composition of the outlet streams can be determined (Table 1). Table 1. Composition of the streams coming out from the first flush-drum (D-101). Component xi’ yi’ C3 0.044584 0.150249 i-C4 0.193807 0.278578 n-C4 0.349461 0.379617 i-C5 0.328347 0.158958 n-C5 0.083801 0.032598  Flow rate and composition of the streams coming out from the second flash-drum D-102 Given the operating pressure and temperature, the Ra chford-Rice equation ' 102 2 1 2 102 ( ( ) 1)( ) 0 1 ( ( ) 1) Nc i i D i iD x k Tf kT         can be solved to find the vaporization ratio α2 = 0.4628. It follows that: V = 0.3471 [kmol/h] L = 0.4029 [kmol/h] The composition of the outlet streams is reported in Table 2. Table 2. Composition of the streams coming out from the…