Vapor-liquidequilibriumusinghysys-100825164743-phpapp01.ppsx

Vapor / Liquid Equilibrium Using HYSYS

yi i P  xi i Pi

sat

Prepared by: A.N.Tabish Lab. Engineer / Lecturer

Department of Chemical Engineering UET, City Campus, Lahore March 31, 2019

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Example # 10.3:* For the system methanol (1) / methyl acetate (2) , the following equations provide a reasonable correlation for the activity coefficient

ln 1  Ax2

2

ln 2  Ax1

2

A  2.771  0.00523T

Where,

In addition following equations provide vapor pressures:

3643.31 lnP1  16.59158  T  33.424 2665.51 sat lnP2  14.25326  T  53.424 sat

Where T is in kelvin and the vapor pressure are in kPa. * J.M.Smith, H.C.Van Ness and M.M.Abott (2005), “Introduction to Chemical March 31,Engineering 2019 [email protected] Thermodynamics”, Ed. 7, pp. 359, McGraw Hill

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CALCULATE: 1. P and {y1}, for T = 318.15 K and {x1}= 0.25 2. P and {x1}, for T = 318.15 K and {y1}= 0.60 3. T and {y1}, for P = 101.33kPa and {x1}= 0.85 4. T and {x1}, for P = 101.33kPa and {y1}= 0.40

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Solution Strategy:     

Start a new case in HYSYS. Define components Select Thermodynamic model. Draw the PFD (material streams) Define

1. 2. 3. 4.

Composition Vapor fraction Mole/mass flow rate Temperature / Pressure

 Determine BUBL/DEW Pressure/Temperature  Determine composition using K-Value information

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HYSYS:

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 

Start a new case in HYSYS. Define components (Methanol + Methyl Acetate).

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

Select NRTL model.

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

Draw the PFD (1 material streams)

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

Vapor Pressure of Methanol

44.51kPa using Antoine Equation



Vapor Pressure of Methyl Acetate

65.64kPa using Antoine Equation

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BUBL Pressure: 1.

P and {y1}, for T = 318.15 K and {x1}= 0.25

73.50 kPa in manual calculations March 31, 2019

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Vapor compositions:

yi Ki  xi

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y1 = 0.278

y1 = 0.282

y2 = 0.722

y2 = 0.718

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DEW Pressure:

2.

P and {x1}, for T = 318.15 K and {y1}= 0.60

62.89 kPa in manual calculations March 31, 2019

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Liquid compositions:

yi Ki  xi

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x1 = 0.8099

x1 = 0.8169

x2 = 0.1901

x2 = 0.1831

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BUBL Temperature: 3.

T and {y1}, for P = 101.33kPa and {x1}= 0.85

331.20K = 58 oC in manual calculations March 31, 2019

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Vapor compositions:

yi Ki  xi

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y1 = 0.671

y1 = 0.670

y2 = 0.329

y2 = 0.330

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DEW Temperature: 4.

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T and {x1}, for P = 101.33kPa and {y1}= 0.40

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326.70K = 53.7 oC in manual calculations 16

Liquid compositions:

yi Ki  xi

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x1 = 0.4517

x1 = 0.4602

x2 = 0.5483

x2 = 0.5398

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VLE Plot:  Download registry files from http://people.clarkson.edu/~wilcox/Design/EqPlots.dll http://people.clarkson.edu/~wilcox/Design/EqPlots.edf and save them to your computer at some safe place.  Create a case containing the components of interest and choose a suitable fluid package.  Go to the Simulation Environment  Go to Tools/Preferences/Extensions and Click on Register an Extension.  Find EqPlots.dll and open it. This will remain part of HYSYS or UniSim on your machine until it is Unregistered. Close Preference.  Go to Flowsheet/Add Operation. Select the Extensions category and Add Equilibrium Plots. This should open the equilibrium plots extension.  For a Binary plot, click the Binary tab at the bottom of the Equilibrium Plots menu, and select the components and the type of plot desired.  For an XY plot, specify either T or P, and click on Plot.  For a TXY plot, specify P. For a PXY plot, specify T. March 31, 2019

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Example # 10.4:* For a mixture of 10 mol-% methane, 20 mol-% ethane, and 70 mol-% propane at 50 (oF), determin: 1. The dew point pressure 2. The bubble point pressure

* J.M.Smith, H.C.Van Ness and M.M.Abott (2005), “Introduction to Chemical March 31,Engineering 2019 [email protected] Thermodynamics”, Ed. 7, pp. 364, McGraw Hill

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Home Work Task: 1. Assuming the validity of Raoult's law, do the following calculations for the benzene (l)/toluene (2) system:

2. For the system ethyl ethanoate (1) and n-heptane (2) at 343.15 K (70"C)

BUBL P calculation for T = 343.15 K (70°C), x1 = 0.05. DEW P calculation for T = 343.15 K (70°C), y1 = 0.05. March 31, 2019

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Home Work Task Contd…. 3. Make the following VLE calculations for the methane (l) / ethylene (2) / ethane (3) system:

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