(Paper) IFS - Indian Forest Service Chemical Engineering Previous Year Paper (2005)

Papers : IFS - Indian Forest Service Chemical Engineering Previous Year Paper (2005)


1. Answer any four of the following (4 x 10 = 40)
What is Bernoulli equation? Determine it for the flow of a compressible fluid in a pipeline.
(b) Discuss, with the help of a sketch, the principle of steam jet ejector for creating vacuum.
(c) Explain the mechanism of heat transfer in nucleate pool boiling of liquids.
(d) Discuss penetration theory of mass transfer. How does it differ from surface renewal theory?
(e) Describe the construction and working of a Swenson-Walker crystalliser.

2. (a) Discuss differential and cumulative methods of screen analysis. (10)
(b) Explain the construction and operation of a plate and frame filter press. (10)
(c) What is area meter? Explain its operation. (10)
(d) Determine an expression for terminal velocity of solid particles settling freely in a fluid stream. Modify the above expression for the case of hindered settling. (10)

3. (a) Differentiate between free and forced convection. Describe the procedure to calculate heat transfer coefficient under free convection. (10)
(b) Explain effectiveness of a heat exchanger. Obtain its expression for a parallel flow heat exchanger in terms of NTU and capacity ratio. (10)
(c) Discuss the effect of boiling point elevation on the capacity of an evaporator. (10)
(d) Define emissivity of a body. How is it related to absorptivity? (10)

4. (a) Derive Rayleigh equation for differential distillation of a binary system. (10)
(b) Discuss pressure drop characteristics of packed columns and explain the significance of flooding point. (10)
(c) Explain the mechanism of moisture movement during drying of a solid. (10)
(d) Briefly explain the construction and operation of a packed extraction tower. (10)

5. Answer any four of the following (4 x 10 = 40)
(a) Explain the concept of cross flow micro filtration along with its advantages over conventional filtration.
(b) Name various types of heads commonly used in cylindrical vessels. Draw their sketches and list areas of applications.
(c) Mention stepwise procedure for the design of a torispherical head for a cylindrical vessel.
(d) What is final value theorem? How is it used to determine response of a system? Explain it with suitable examples.
(e) Discuss cascade control and its application in process industries.

6. (a) Describe procedure of immersion precipitation process for the production of membranes. (10)
Explain, with the aid of a sketch, the working of an electro dialysis. (10)
(c) What is pervaporation? Explain it with the help of a neat sketch and also indicate areas of its application. (10)
(d) Discuss ion-exchange separation process for the demineralization of water. (10)

7. An autoclave of 7.9 m3 volume capacity has ellipsoidal heads (major to minor axis ratio = 2:1) at its top and bottom ends. The autoclave is subjected to a maximum pressure of 8 MN/m2. The allowable stress of the material (carbon steel) is 1040 MN/m2. Weld joint efficiency is 85 per cent. Determine optimum dimensions of the autoclave if the following cost ratios are applicable:

(a) The cost of fabricated shell is estimated to vary inversely with D”4 where D is the inside diameter of the autoclave.
(b) The fabricated cost of top and bottom heads per unit weight is 1.5 times the fabricated cost of shell per unit weight. A 12 mm plate is available in store. Check if it can be used for the fabrication of shell of the autoclave. Alternatively, suggest the suitable thickness of plate required for the fabrication of shell of the autoclave. (40)

8. (a) What are phase margin and gain margin? Discuss their utility in control tunnings. (10)
(b) Discuss procedure for plotting of open loop transfer function by root locus method. (10)
(c) How do you measure liquid level if the liquid contains suspended solid particles? Suggest measuring instrument along with the principle of working. (10)
(d) Explain elements of a computer control system. (10)

1. Answer any four of the following:
(a) Find the first-order rate constant for the disappearance of A in the gaseous reaction 2A → R, holding the pressure constant, the volume of the reaction mixture starting with 80 per cent A decreases by 20 per cent in 3 mm. (10)

(b) A solution contains 50 per cent benzene, 30 per cent toluene and 20% xylene by weight at 100° C. The vapours are in contact with the solutions. Calculate total pressure and mole per cent composition of liquid and vapour: (10)

(c) Show that the internal energy of an ideal gas is a function of temperature only. (10)
(d) For adiabatic batch reactor, derive an expression to determine the time required to achieve a desired conversion. (10)
(e) Define Bubble point and Dew point. Explain in detail how to calculate bubble point or dew point of given binary mixture. (10)

2. The elementary reaction. A + B → R + S is effected in a set up consisting of a mixed reactor into which two reactant solutions are introduced followed by a PFR. A large enough of excess of B is used so that the reaction is first order w.r.t. A. It is proposed to reverse the order of two units. How does this change affect the conversion? (40)

3. A high purity limestone is burnt in a lime kiln which is fired externally with a coal containing 75.5 per cent C, 5.5 per cent H, 1.6 per cent N, 1.1 per cent S, 7.6 per cent and rest ash. The stack gas analysis is 20.2% CO2, 7.1% O2 and rest N2,
(a) kg limestone burnt/kg of coal;
(b) excess air used for combustion. (40)

4. One mole of an ideal gas initially at P1 and T1 is compressed reversibly and adiabatically till the pressure is P2 and then it is cooled at constant volume to the initial pressure, finally the gas is restored to the initial state through an isobaric process. Calculate the work done by the process. (40)

5. Answer any four of the following:
(a) Define depreciation. What are the different methods for determining depriciation? Explain the method, sum of the years digit method. (10)
(b) Explain briefly the factors to be considered for the location of a chemical plant. (10)
(c) Describe the manufacture of caustic soda by either diaphragm or mercury cell process. Discuss the pollution aspects of this industry. (10)
(d) Explain briefly the pollutants emitted from a tanning industry. (10)
(e) Explain the cracking and polymerisation of petroleum fractions. (10)

6. (a) Explain the break-even analysis and its equation. (10)

(b) A Project can produce 12000 units per year at 100 per cent capacity. The variable cost per unit is Rs. 3 at 100 per cent capacity. Fixed costs are Rs. 10,000 per year. Find the break-even point if the selling price is Rs. 5/ unit. Now the manufacturer finds that he can sell only 80% at Rs 5/ unit. How much should he charge for additional units if he brings production upto 100 per cent capacity and increases profits after taxes by an additional amount of Rs. 1,000? Use tax rate for the above problem 52 per cent. . (30)

7. (a) Describe the process with neat flow sheet of the manufacture of ethyl alcohol. (30)
(b) Discuss the applications of following products: (10)
(i) Enamel paint (ii) Rancidity.

8. (a) Discuss the methods possible for preventing various industrial hazards. (20)
(b) Explain primary treatment method of waste-water treatment. (20)