Introduction To Chemical Engineering

Set No. 1

Code No: R05010803

I B.Tech Supplimentary Examinations, Aug/Sep 2007 INTRODUCTION TO CHEMICAL ENGINEERING (Chemical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Briefly discuss about the following mechanical operations: (a) Filtration (b) Flotation.

[8+8]

2. (a) What is the use of making a material balance and an energy balance? (b) Write about the principle of conservation of mass and give the steps involved in making mass balance calculations. [4+12] 3. Obtain Bernoulli’s equation from mechanical energy balance for steady flow. [16] 4. Derive the expression for log mean temperature difference for parallel flow heat exchanger. What are the conditions under which it is valid? [16] 5. (a) Write the relation between individual and overall mass transfer coefficients and also mention units of each. (b) Briefly explain design of packed adsorption column.

[6+10]

6. (a) Explain plate efficiency. What are different types of plate efficiencies? (b) Write on any two of the following:

[6+10]

i. Flash distillation ii. Steam distillation iii. Azeotropic distillation. 7. Discuss about the following terms for gas-liquid mass transfer operations: (a) Weeping (b) Entrainment (c) Hold-up (d) Axial mixing. 8. (a) Define the following terms pertaining to drying: i. ii. iii. iv.

Bound moisture Unbound moisture Wet basis Dry basis 1 of 2

[16]

Set No. 1

Code No: R05010803

(b) Write about the construction and operation of tray dryers with a neat diagram. Mention its uses and advantages. [8+8] ⋆⋆⋆⋆⋆

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Set No. 2

Code No: R05010803

I B.Tech Supplimentary Examinations, Aug/Sep 2007 INTRODUCTION TO CHEMICAL ENGINEERING (Chemical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Define fundamental units and dimensions useful in chemical engineering, write dimensional formulae for Force and Energy. (b) Define the units of major eight (8) quantities used in SI system. (c) Explain the basis of dimensional analysis. 2. (a) Write the energy balance equation for the following: i. ii. iii. iv.

[4+8+4] [4×2=8]

Non-flow process Non-flow process at constant volume Non-flow process at constant pressure Flow system.

(b) Give the steps to be followed in making energy balance calculations.

[8]

3. (a) What is a streamline? Obtain the equation for a streamline. (b) Show the velocity distribution of a fluid flowing in a long straight pipe for laminar, turbulent and plug flow. Explain the reason for the difference in the profiles. (c) Define three dimensional flow.

[6+8+2]

4. (a) Explain the mechanism of heat transfer by thermal radiation. (b) What is a perfectly black body? Describe Fery’s black body. (c) State the following laws and explain the terms:

[4+4+8]

i. Stefan-Boltzmann law ii. Planck’s law. 5. (a) The equilibrium in vapor-liquid systems is governed by the phase rule. Discuss. (b) What are boiling point diagrams? Explain with a neat figure.

[6+10]

6. (a) Define “Reflux Ratio”. (b) Describe the McCabe-Thiele method of calculation of number of theoretical stages. [4+12] 7. (a) What are the two main categories into which industrial liquid-liquid contactors are classified? Discuss about each category. (b) Describe the construction and working of a rotating disc contactor. Where is it used and what are its advantages? [6+10] 1 of 2

Set No. 2

Code No: R05010803

8. Describe the construction and operation of tray dryers and rotary dryers with neat diagrams. Mention their uses and advantages. [16] ⋆⋆⋆⋆⋆

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Set No. 3

Code No: R05010803

I B.Tech Supplimentary Examinations, Aug/Sep 2007 INTRODUCTION TO CHEMICAL ENGINEERING (Chemical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Give a brief account of the following: (a) Screening (b) Size reduction.

[8+8]

2. (a) Describe the different types of flow diagrams.

[8]

(b) Differentiate between i. Batch process and continuous process ii. Recycling and Bypassing.

[4+4]

3. The total energy content of a fluid element in motion has several components. Discuss in detail and obtain the total energy balance for steady flow. [16] 4. (a) Explain heat conduction through a composite plane wall with a neat figure. Also, derive the equation for the rate of heat transfer. (b) The mean area for heat transfer depends on the shape of the solid. State the different ways in which it can be expressed for different shapes of solids. [10+6] 5. (a) Name two mass transfer operations for the following phases in contact: i. liquid-liquid ii. solid-vapor. (b) Mention the similarities between various mass transfer operations. (c) Many differences exist between various mass transfer operations. Explain with examples. [8+4+4] 6. (a) Explain plate efficiency. What are different types of plate efficiencies? (b) Write on any two of the following:

[6+10]

i. Flash distillation ii. Steam distillation iii. Azeotropic distillation. 7. (a) Define the following terms with respect to gas-liquid mass transfer operations: i. Cross flow ii. Dual flow iii. Split flow 1 of 2

Set No. 3

Code No: R05010803 iv. Turndown ratio.

[4×2=8]

(b) Explain the following terms and give their effect on the gas-liquid mass transfer operation: i. Entrainment ii. Weeping.

[4+4]

8. (a) What is an adsorption isotherm? What information can be obtained from it? Mention other ways of representing equilibrium adsorption data. (b) What are the desirable characteristics of adsorbents? Give at least four examples of adsorbents widely used. (c) Differentiate between regeneration and reactivation of adsorbents. ⋆⋆⋆⋆⋆

2 of 2

[6+6+4]

Set No. 4

Code No: R05010803

I B.Tech Supplimentary Examinations, Aug/Sep 2007 INTRODUCTION TO CHEMICAL ENGINEERING (Chemical Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Explain the Rayleigh and Buckingham methods of dimensional analysis.

[16]

2. (a) State Hess’s law of heat summation and explain how heat of reaction can be calculated. (b) Discuss the effect of pressure and temperature on heat of reaction. [8+8] 3. (a) Differentiate between a pump, a fan and a compressor. (b) What is a multistage pump? Explain. (c) Give a brief account of rotary pumps.

[6+4+6]

4. Write a note on multiple-effect evaporators and methods of feeding with suitable diagram. [16] 5. (a) What are the combination of parameters used to study binary vapor-liquid equilibrium systems? Show how they can be obtained from phase rule. (b) Define relative volatility in terms of partial pressure of pure component and mole fraction in liquid phase for a binary system obeying Raoult’s law. Derive the exression for yA in terms of αAB and xA . (c) Absorption or stripping processes may be handled either statically or kinetically. Explain. [6+6+4] 6. (a) Write about azeotropic distillation and extractive distillation. (b) Discuss the principles of simple batch distillation. 7. (a) Write short notes on: i. Cross current extraction. ii. Counter current extraction. iii. Fractional extraction. (b) Define the terms “ Extract” and “Raffinate”.

[8+8]

[12+4]

8. (a) Define the terms dew point, humidity, percentage humidity, percentage relative humidity and dry bulb temperature. (b) Explain the working principle involved in each of the following: [10+6] i. Humidifiers, ii. Dehumidifiers and iii. Water coolers ⋆⋆⋆⋆⋆ 1 of 1