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ITK-234 Termodinamika Teknik Kimia II (2 SKS) Dicky Dermawan

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Presentasi berjudul: "ITK-234 Termodinamika Teknik Kimia II (2 SKS) Dicky Dermawan"— Transcript presentasi:

1 ITK-234 Termodinamika Teknik Kimia II (2 SKS) Dicky Dermawan

2 Sylabus: Multicomponent Thermodynamics Phase Equilibria(80%) Phase Equilibria(80%) Chemical Equilibria(20%) Chemical Equilibria(20%)

3 Textbooks & References Smith, Introduction 2 Chemical Engineering Thermodynamics Smith, Introduction 2 Chemical Engineering Thermodynamics Daubert, Chemical Engineering Thermodynamics Daubert, Chemical Engineering Thermodynamics

4 Score & Grade 20 4 all homework & quiz st midterm exam nd midterm exam 30 4 final term examination   A   B   C   D

5 Phase Equilbria: Raoult’s Law

6 Nomenclature Closed System x i : mol fraction in liquid phase y i : mol fraction in gas phase i = 1,2,3,… Sorted by vapor pressure from the higher one Vapor pressure: tendency of certain liquid to vaporize The higher the temperature, the higher the vapor pressure

7 Vapor Pressure Model Antoine P [=] torr t [=] o C

8 Antoine Vapor Pressure Model P [=] torr t [=] o C

9 Antoine Vapor Pressure Model P [=] torr t [=] o C

10 What will be needed in the near future: Hand Calculator Computer Programs Microsoft Excel Microsoft Excel MathCAD MathCAD

11 Phase Equilibria Problem Relation among T, P, x i & y i at equilibrium condition Relation among T, P, x i & y i at equilibrium condition

12 Experimental Approach Mixture: Methyl-ethyl-ketone (1) / Toluene (2) Temperature: 50 o C Plot the P-x-y diagram

13 Typical Diagram t-x-y diagram P-x-y diagram

14 Experimental Approach - Drawback For the same binary mixture: Methyl-ethyl-ketone (1) / Toluene(2) What if we need the equilibrium data at 40 o C? You’ve got to make experiment at that temperature! What if we need the equilibrium data at 50 o C? You already have one! What if we need the equilibrium data at 60 o C? You’ve got to make experiment at that temperature! Even for a simple binary mixture we must carry out many experiment in order to gather data

15 Experimental Approach - Drawback What about other binary mixture: Chloroform (1) / Dioxane (2) You’ve got to perform other experiments! How many experiment should be carried out to obtain binary mixture vapor – liquid equilibria from a combination of 8 components? Diethyl ketone (1) / n-hexane (2) Acetonitrile (1) / Nitromethane (2) You’ve got to perform other experiments! Waw!

16 Experimental Approach - Drawback What about ternary mixture such as: Benzene (1) / Toluene (2) / Ethylbenzene (3) ? You’ve certainly got to perform other experiments! You know the answer! How many experiment should be carried out to obtain mixtures vapor – liquid equilibria from a combination of 100 components? Waw! What about multicomponents mixture such as: Ethane (1) / Propane (2) / Isobutane (3) / Isopentane (4) ?

17 Fundamental Question Do we really have to do these experiments? 100 years ago the answer is Yes! Not now! That’s why we take this course, folks!

18 Thermodynamics Approach: Criteria for System in Equilibria The chemical potential of i-th component is defined as:

19 Criteria for Vapor - Liquid Equilibria The chemical potential of i-th component is defined as:

20 Raoult’s Law For ideal gases: For ideal solution: Neglecting effect of pressure on, we obtain: Raoult’s law The chemical potential of i:

21 Construction of Phase Diagram Using Raoult’s Law: Binary Mixture

22 Physical Interpretation of Phase Diagram: Pxy

23 Physical Interpretation of Phase Diagram: txy

24 Berdasarkan Diagram, Tentukan dan Tunjukkan: a. Titik didih normal asetonitril b. Fasa campuran dengan fraksi mol asetonitril = 0,22 pada tekanan 70 kPa dan suhu 95 o C c. Bila campuran ekimolar bersuhu kamar 25 o C dipanaskan perlahan-lahan hingga mendidih, tentukan komposisi uap yang mula-mula terbentuk d. Pada temperatur berapa seluruh cairan pada (c) teruapkan ? e. Uap yang diperoleh pada (c) dikondensasikan. Cairan ini kemudian dibiarkan setimbang dengan uapnya pada tekanan 70 kPa. Gambarkan proses ini dalam diagram dan tentukan komposisi uap baru yang terbentuk.

25 Raoult’s Law: Binary Mixture

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27 Type of Phase Equilibria Calculations Given T & P, find the equilibrium composition x i, y i BUBL P calculation: Given T & liquid composition x i, Find the bubble point P b & vapor composition DEW P calculation: Given T & vapor composition y i, Find the dew point P d & vapor composition

28 Type of Phase Equilibria Calculations BUBL t calculation: Given P & liquid composition x i, Find the bubble point t b & vapor composition DEW t calculation: Given P & vapor composition y i, Find the dew point P d & vapor composition FLASH calculation: Given P, T & overall composition, Find the fraction of system which is liquid (L) & vapor (V) and their respective compositions x i & y i

29 Raoult’s Law; Binary Mixture

30 Type of Phase Equilibria Calculations a. Given T= 100 o C & P = 1 atm, find the equilibrium composition x i, y i b. BUBL P calculation: Given T = 100 o C & liquid composition x 1 = 25% Find the bubble point P b & vapor composition c. DEW P calculation: Given T = 100 o C & vapor composition y 1 = 25%, Find the dew point P d & dew composition

31 Type of Phase Equilibria Calculations d. BUBL t calculation: Given P = 1 atm & liquid composition x 1 = 25% Find the bubble point t b & vapor composition e. DEW t calculation: Given P = 1 atm & vapor composition y 1,= 25% Find the dew point t d & dew composition f. FLASH calculation: Given P = 1 atm, T = 115 o C & overall composition, z 1 =25% Find the fraction of system which is liquid (L) & vapor (V) and their respective compositions x i & y i

32 Do we always have to prepare phase diagram to make calculation? No, we don’t have to We can just perform the calculations

33 Raoult’s Law: Binary mixture

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35 Extension to Ternary and Multi Component Mixtures We can’t even prepare the diagram! But we still able to make the calculations

36 Raoult’s Law: Ternary Mixture

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41 KUIS 1 HUKUM RAOULT Kamis, 15 Maret Dengan asumsi keberlakuan Hukum Raoult, sketsalah diagram txy untuk campuran biner benzena(1)/etilbenzena(2) pada tekanan 101,33 kPa. Berdasarkan diagram yang saudara konstruksi, tentukan dan tunjukkan dalam diagram: a. Titik didih normal etilbenzena b. Fasa campuran dengan fraksi mol etilbenzena = 0,22 pada tekanan atmosferik dan suhu 110 o C c. Bila campuran ekimolar bersuhu kamar 25 o C dipanaskan perlahan-lahan hingga mendidih, tentukan komposisi uap yang mula-mula terbentuk d. Pada temperatur berapa seluruh cairan pada (c) teruapkan ? e. Uap yang diperoleh pada (c) dikondensasikan sehingga mencair. Cairan ini kemudian dibiarkan setimbang dengan uapnya pada tekanan atmosferik. Gambarkan proses ini dalam diagram dan tentukan komposisi uap baru yang terbentuk. Tekanan uap masing-masing komponen murni mengikuti persamaan:

42 KUIS 1 HUKUM RAOULT Kamis, 15 Maret Kesetimbangan uap - cair campuran biner n-pentana(1)/n- heptana(2), karena kemiripan struktur molekulnya, dapat diasumsikan memenuhi hukum Raoult. Pada tekanan konstan 115 kPa: a. Tunjukkan bahwa campuran dengan komposisi60% mol n-pentana pada suhu 100oC berfasa uap b.Campuran pada (a) didinginkan perlahan-lahan hingga uap mengembun sedikit demi sedikit. Perkirakan suhu yang diperlukan untuk mengembunkan 50% dari uap pada (a)


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