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Code :9A23404 1II B.Tech II Semester(R09) Regular Examinations, April/May 2011

THERMODYNAMICS IN BIOPROCESS SYSTEMS(Biotechnology)

Time: 3 hours Max Marks: 70Answer any FIVE questions

All questions carry equal marks⋆ ⋆ ⋆ ⋆ ⋆

1. (a) What is enthalpy? Is enthalpy a path function?

(b) One kilogram mass of water is vaporized at 250C and 1 atmospheric pressure; calculate∆U and ∆H if 10.2374*104 joules heat is added to water.Data: Specific volume at 1 atm, 250CLiquid water = 1.044*10−3

Water vapor = 1.68 m3/Kg.

2. (a) A kilogram of water at 273 k is brought into contact with a heat reservoir at 373 k. Whenthe liquid water has reached 373 k, what is the entropy change of the water and that ofthe reservoir? What is ∆Stotal?

(b) Derive the expression for change of entropy for an ideal gas.

3. (a) Show that chemical potential of component in all phases are equal at equilibrium.

(b) Explain briefly estimation procedure for partial property from solution property.

4. (a) Derive an expression for fugacity coefficient of a pure component.

(b) Calculate the fugacity of a gas at 2000C & 500 atm from the following data.P atm 50 100 200 400 800Z 0.98 0.99 1.04 1.26 1.80

5. (a) Define residual property and derive the expression to calculate residual enthalpy

(b) Prove TdS = CpdT-T(∂V∂T

)pdP

6. (a) Prepare a t-x-y diagram for the ideal binary system bezene (1) - ethyl benzene (2) at 101.3Kpa. Vapour pressure of the pure species are given byIn P1

sat=13.8858-2788.51/(t+220.79)In P2

sat =14.0045-3279.47/(t+213.20)

(b) Explain briefly about solid - liquid equilibrium diagrams.

7. (a) Explain Lewis-Randall rule and Henry’s law. For a binary system, show that if Henry’s lawis applicable for one component, Lewis-Randall rule is applicable for the other component.

(b) Define activity and activity coefficient.

8. In a laboratory investigation, acetylene is catalytically hydrogenated to ethylene at 11200C and1 bar. If the feed is an equimolar mixture of acetylene and hydrogen, what is the compositionof the product stream at equilibrium? The reactions areC2H2 −− → 2C +H2

2C + 2H2 −− → C2H4

K1 = 4 ∗ 105

K2 = 2.5 ∗ 10−6

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JNTUWORLD

Code :9A23404 2II B.Tech II Semester(R09) Regular Examinations, April/May 2011

THERMODYNAMICS IN BIOPROCESS SYSTEMS(Biotechnology)

Time: 3 hours Max Marks: 70Answer any FIVE questions

All questions carry equal marks⋆ ⋆ ⋆ ⋆ ⋆

1. A pressure gauge fitted to a steam boiler records a pressure of 34 bars. The vacuum gauge onthe condenser indicates 0.94 bar. If the atmospheric is 1 bar, calculate

(a) The final temperature,

(b) The change in internal energy

(c) The change in enthalpy and

(d) The heat transfer. Take R = 0.259KJ/kg K and Cv= 0.652KJ/Kg K for oxygen.

2. (a) A Carnot engine I operate between two reservoirs at temperatures 1920k and T K whilea second Carnot engine ii operates between two reservoirs at T K and 300 K. It is foundboth the engines have the same efficiency. Determine the value T.

(b) Explain in detail the Carnot cycle of the heat engine and applicability of second law ofthermodynamics.

3. Derive the relation for the calculation of Gibbs free energy of ideal gas mixture, starting fromfundamental property relation.

4. (a) Calculate the fugacity of CO2 at 1000F and 200 psia from volumetric data.P(psia)1 10 20 40 80 120 160 200 240V(ft3/lb) 136.6 13.61 6.778 3.363 1.657 1.088 0.8033 0.6376 0.5237

(b) State Gibbs theorem and obtain expressions for excess for properties for enthalpy, entropyand Gibbs free energy.

5. (a) Obtain fundamental property relations for a homogeneous fluid of constant compositionfrom basic definitions of various potentials.

(b) Derive Maxwells equations.

6. (a) Derive an equation for VLE which is in thermodynamic consistency check.

(b) Mixture of n-pentene and n-heptane obeys ideal solution behavior. Prepare p-x-y diagramat 700C. Antoine equation may be to calculate the vapor pressure: log10

p = A-B/(t+c)Where pin torr and t is in 0C.Component A B Cn-pentene 6.87632 1075.780 233.205n-heptane 6.89386 1264.370 216.640

7. (a) Define and explain partial property along with necessary equation

(b) The partial molar volume of ethanol in a 60% ethanol - water solution is 5.5*10−6m3. Thedensity of the mixture is 849.4Kg/m3. Calculate the partial molar volume of water in themixture.

8. Acetaldehyde is manufactured by dehydrogenation of EthanolC2H5OH −− → CH3CHO +H2Standard heat of this relation is 16.612 cal/gmol. The free energy change in cal/gmol is givenby G = 16.350 - 28,2T, T is in K.Calculate the maximum percentage of acetaldehyde that could be obtained from an isothermalreactor, operated at 323 K. What would be the effect of using 80 mole % alcohol rather thanpure alcohol.

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Code :9A23404 3II B.Tech II Semester(R09) Regular Examinations, April/May 2011

THERMODYNAMICS IN BIOPROCESS SYSTEMS(Biotechnology)

Time: 3 hours Max Marks: 70Answer any FIVE questions

All questions carry equal marks⋆ ⋆ ⋆ ⋆ ⋆

1. (a) A lean and thin man, who can lift a body of mass 100 Kg where g=9.81 m/s2, claims thathe can lift a body of mass 150 Kg. His friend did not agree and both went in to a bet.They go high in space to a H, height where the lean and thin man lifts the body of mass150 Kg. If ‘g’ decreases at the rate 0.01 cm/s2 per 1000m of ascent, what is the value ofH?

(b) Differentiate between closed system and isolated system giving proper explanations.

2. (a) State and prove Carnot’s theorem.

(b) Prove that it is not possible to obtain zero degress on thermodynamic temperature scale.

(c) Heat is transferred from a vapour at 4200C to water to evaporate at 2500C. The steam sogenerated is used in a power cycle to reject the heat to atmosphere at 350C. What is theloss in a available energy while the heat is transferred over a finite temperature differenceduring evaporation of water?

3. (a) Define the terms: An ideal liquid solution, Raoult’s law, fugacity. Chemical potential

(b) State and explain the equilibrium criteria usually applied by biotechnologists in the solu-tion of phase equilibrium problems.

4. (a) Derive the expression for activity coefficient if solution follows the Margules equation asmodel solution behavior?

(b) Define partial property.

5. (a) Draw and explain Mollier diagram, PH diagram, TS diagram

(b) Show that (∂p∂t)V = ( ∂s

∂v)T

6. (a) Assuming the validity of Raoult’s law, prepare a t-x-y for 80 Kpa for chlorobutane (1)-chlorobenzene (2) system. Antonie parameters are as follows:log10P = A-B/(t+C) Wherepin torr and t is in 0C.Chlorobutane: A= 13.96 B= 28866.26 C= 224.10Chlobenzene: A= 13.993 B= 3295.12 C= 217.55.

(b) Explain briefly LLE diagrams.

7. (a) What does Gibbs/Duhem equation relate?

(b) A mixture of chloroform & acetone with 66.6 mol% of chloroform forms an azeotrope at64.50C and 1 atm. At this temperature, the vapor pressure of chloroform is 858 mm Hg.Find the activity coefficient of chloroform in the mixture.

(c) How fugacity of pure component calculated?

8. (a) A mixture of N2,H2, and Argon in the mole ration 1:3:2 enters in a catalytic reactor forthe synthesis of ammonia. The reactor is maintained at 4000C and 20 Mpa. Estimate thedegree of conversion and the equilibrium constant is given as K=1096*104

(b) Write the effect of temperature , pressure and inerts on equilibrium constant.

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Code :9A23404 4II B.Tech II Semester(R09) Regular Examinations, April/May 2011

THERMODYNAMICS IN BIOPROCESS SYSTEMS(Biotechnology)

Time: 3 hours Max Marks: 70Answer any FIVE questions

All questions carry equal marks⋆ ⋆ ⋆ ⋆ ⋆

1. The piston of a piston cylinder device containing a gas has a mass of 75 Kg. diameter of piston is 250mm. The local atmospheric pressure is 0.97 bars gravitational acceleration is 9.8 m/s2.

(a) Determine the pressure inside the cylinder.

(b) If some heat is transferred and its volume doubles, do you expect the pressure inside the cylinderto change?

2. (a) State and explain third law of thermodynamics

(b) A steel casting [Cp=0.5 kJ kg−1K−1] weighing 40kg and at temperature of 4500C is quenched in150 kg of oil [Cp = 2.5 kJ kg−1K−1] at 250C. if there are no heat losses, what is change in entropyof (i) the casting, (ii) the oil and (iii) both considered together.

3. (a) Show that chemical potential of component in all phases are equal at equilibrium.

(b) What is ideal solution and define Raoults law.

4. Define and explain the terms: Molar Gibbs energy, Standard state Gibbs energy, Partial Gibbs energy,Excess Gibbs energy and residual Gibbs energy. Bring out the differences amongst them with simplethermodynamic relations.

5. (a) Show that(∂T∂V

)S= −

(∂P∂S

)V

(b) A particular thermodynamic system has the following fundamental relation U=CS2/VN, whereC is a constant. Transform the given fundamental relation into the enthalpy representation.

6. For the system acetone (1) - acetonitrile (2) the vapour pressure of the pure species are given byInp1sat = 14.5463 - 20940.46/t+237.22,Inp2sat= 14.2724 - 2945.47/t=224.0Where t is in 0C and the vapour pressure are in kPa. Assuming Raoult’s law to describe the vapour-liquid equilibrium of the system, determine.(i) x1 and y1 for the equilibrium phases at 540C and 65 kPa.(ii) t and Y1 for P = 65 kPa and x1 = 0.4.(iii) P and Y1 for t = 540C and x1 = 0.4.

7. (a) The nees arises in a laboratory for 2000 cm3 of an antifreeze consisting of a 30 mole percentsolution of method in water. What volumes of pure methanol and of pure water at 250C must tomixed to form the 2000 cm3 of antifreeze? Partial molar volumes of methanol and water in a 30mole percent methanol solution at 250C are 38.632 and 17.765 cm3/mol respectively and that ofpure component volumes of methanol and water are 40.727 and 18.068 cm3/mol, respectively.

(b) Differentiate between activity coefficient and fugacity coefficient.

8. Estimate the equilibrium constant k at 1000 K and 1 bar for the water gas shift reaction(CO2 +H2 → CO +H2O) taking into the account the variation of ∆H0 with temperature.Data : ∆G0

298 = 28618J ;∆H0298 = 41166J,

Specific heat data:A 103B 10−5D

CO(g) – 3.376 0.557 -0.031H2O(g) – 3.470 1.450 0.121CO2(g) – 5.457 1.045 -1.157H2-(g) – 3.249 0.422 0.083

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