IFS Chemical Engineering 2009

7/23/2019 IFS Chemical Engineering 2009

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Serial No [ 0415 l [ -JGT J-DIFA

CHEMICAL ENGINEERING

Paper-[

Time

Allowei

Three Hours) ( M:-:-ax-im_u_m_M:-:-a-rks:-.-.

-2-o o)

INSTRUCTIONS

Candidates should attempt Question Nos. 1 and 5

which are compulsory, and

THREE of

the

remaining questions, selecting at least

ONE question from each Section.

The number ofmarks carried by e .ach question is

indicated at the end of the question.

Answers must be written

in

ENGLISH

only.

Assume suitable data, i considered necessary, and

indicate the same clearly.

Neat sketches may be drawn, wherever required.

SECTION-A

1 Answer any

FOUR of

the following JQX4=40

a) Classify fluids rheologically on the basis

of

their

stress-strain relationship. Explain them with

examples.

10

b)

Discuss flow pattern caused

by

a turbine type

impelter in an agitated tank. Mention ways to

prevent swirling and vortex

agitated tank.

I)

formation in the

10

Contd.)

•



2

3

(c) (i) Define capacity and effectiveness

of

a screen.

(d)

(c)

(a)

b)

(c)

d)

(a)

Derive

an expression for the

overall

effectiveness

of

a screen.

(ii) State Rittinger s law

of

crushing. Mention its

limitations.

Discuss, the mechanism

of

nucleate boiling. How

does it differ from film boiling

10

Discuss, with the help

of

a sketch, the principle

of

a steam jet ejector for creating vacuum.

10

(i)

Differentiate between

differential

and

cumulative analysis to find the average size

of a sample.

5

(ii)

What is a ball mill ? Derive an expression

for its critical speed.

5

Determine

an

expression for terminal velocity

of

solid particles settling in a fluid

s ~ r e m

under

hindered condition. How will you modify it when

the container is

of

limited size

?

10

Explain the construction and operation of a plate

and frame filter press.

State the difference between washing and non-

washing plate.

10

What is an ultrafine grinder ? Explain its principle

and operation.

10

Draw boiling curve and explain various regjmes

occurring therein. What is the significance of

critical heat flux point on the curve

10

(2)

Comd.)



(b)

Compare forward feed double effect evaporator

with backward feed dQuble effect evaporator.

10

(c) What is boiling point elevation? Discuss its effect

on the capacity

and

steam economy of an

evaporator.

10

(d) Briefly describe the procedure

to

calculate radiant

heat load

of

an oil fired furnace.

I 0

4

{a)

Discuss clearly

the

concept

of

film transfer

coefficient

and

overall transfer coefficient

in

mass

transfer.

How does penetration theory of mass transfer differ

from surface renewal theory ? I 0

(b) Explain the construction and operation of a packed

extraction tower

I 0

(c)

(i)

Define relative volatility . How can it be

used to draw equilibrium curve of a binary

system?

(ii)

Mention

limitations of

McCabe Thiele

method. How

are these overcome in Ponchon-

Savarit method ?

s

(d) With a neat drying rate curve, explain various zones

of drying. Mention the mechanism of moisture

movement in each zone. I 0

3)

Corud.)



SECTION 8

5. Answer any

OUR

of the following

10x4=40

(a) Explain stepwise procedure for the design

of

an

elliptical head for a cylindrical vessel.

{b) Discuss failure of vessels based on the theory of

plasticity.

(c) Name various supports generally used for process

vessels. Give their advantages and disadvantages.

(d) Develop an expression for frequency response of

a transportation lag. Show it graphically

thro

a

sketch.

(e) Discuss procedure for plottingofopen loop transfer

function by root locus method.

6. a) What is

pervaporation

Explain it with the help

of a neat sketch and also indicate its areas

of

application.

10

(b)

Discuss various types of membranes. Mention

procedure

of

immersion precipitation process for

the production

of

a membrane. I 0

(c) Describe dialysis and electrodialysis processes.

Give

their areas of applications.

Briefly explain

the working of an instrument based

on electrodialysis. 1

4)

Contd.)



d)

What is Super Critical Fluid Extraction ? Compare

super critical fluid with the conventional fluid as

a solvent. Give areas of application of super critical

fluid extraction process.

10

7.

(a) Describe Coate's theoretical analysis for bending

•

stress at the head-shell junction

of

a vessel.

10

(b)

Explain the design equations for calculating the

thickness

of

cylindrical and spherical shells. How

will

you select a standard plate for the fabrication

of a shell ?

10

(c) Estimate the thickness

of

the shell and head of

a process vessel. The vessel is a cylinder having

ellipsoidal heads (major to minor axis ratio =

2 : I at

its

bottom and top ends. The_ inside

diameter and length of the vessel are I · m and

2 m respectively. The vessel is

to

operate at a

pressure

of 1·4

MN/m

2

(absolute}. The allowable

stress for

the

material (plain carbon steel) is

85

im

2

Weld is

fully

radiographed. A corrosion

allowance

of

2 mm may be taken.

Take design pressure as 10 above operating

pressure.

10

d)

What are the various stresses on a tall vessel

to

be

installed in a seismic zone ?

10

5}

(Contd.)



8. {a) How

do

you measure liquid level

if

the liquid

contains suspended solid particles ? Suggest a

suitable measuring instrument and explain its

working principle. I 0

b) Explain the following:

i) Negative and

positive

feedback control

systems

5

ii) Servo and regulatory control problems.

c) Develop a transfer function between pressure drop

and

the

manometer reading

for

a

mercury

manometer. State the assumptions made.

I 0

d) Explain the working

of

a PID control system. Draw

a pneumatic control

cir:cuit for

this system and give

its characteristics. I 0

6)



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flam e

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nd

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In

w

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atio

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B

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(c)

Compare

and

il UEtrate the

interpretation

of

kinetic

data

by integral

method

of

analysis with

that of

differential method of analysis.

(d)

Pure

oxygen

is

mixed

with

air

to

produce

an

ellriched

air

containing 50% by volume

of

oxygen.

Determine the

ratio of air to oxygen used.

(e)

Explain

about temperature

effects and

runaway

reactions.

2. (a)

Explain aOOut

recycle, bypass, purge

and

Kopp's

Rule.

1

(b) The analysis

of gas

entering the

secondary

converter in a contact

sulphuric

acid plant is

4

of

80

2

, 13%

of

2

and

83% N

2

(volume basis). In

a

converter

S0

2

is

oxidised to

80

3

.

The

gases

leaving

the

converter contain

0·45% S0

2

on

S0

3

free

basis.

Calculate conversion

of

S0

2

.

2

(c)

An aqueous

solution

of2·45

by

weight

sulphuric

acid, has a specific gravity

of

1·011.

Express

the

composition

of sulphuric

acid

in

normality.

1

S. (a)

If the density

of

gaseous

ammonia

at

473 K

and

50

bar

is 24·3 kg M"

3

,

estimate

its

fugacity.

2

(b)

Calculate the

fraction of pure

ethane that

would

dehydrogenate

at

750 K

and

5

atm, i

the

following reaction takes place at

equilibrium

:

K

= >J2·576

kJ.

2

6-JGT

J D1FB

2

[Contd J



4. (a) Find the first order rate constant. for the

disappearance of A in the gas reaction 2A R if,

on holding the pressure constant, the volume of

reaction mixture, starting with

80

A, decreases

by

20 in 3 minutes. 2

(b} A gaseous feed of pure A (one mole/litre) enters a

mixed flow reactor of 2 litres volume and reacts

as follows :

2 A ~ > R - rA::: 0·05c molellitre.sec.

Find what feed rate will give an

outlet

concentration of CA

' 0·5

mole/litre. 2

B JGT J DIFB

3

IContd.]



r

I

SECTION B

5. Answer

any four

of

the

following

maximum

150 words

each): 4x1 =4

6.

a) Explain about atmospheric distillation of crude

oiL

b) Explain about edible oils extraction. Compare

and

contrast Soaps

vs, Detergents.

c) Explain about the reason for ozone layer

depletion

and

acid rain.

d) Discuss about solid wastes hazards and their

disposal techniques.

e)

Explain about net present value by discounted

cash flow.

Ia

Give an account of coal chemicals.

b)

Discuss

manufacture

of ammonia NH

3

)

with

a

neal flow

sheet.

{o

Explain how poly vinyl chloride is manufactured.

7.

Explain

the

extent of

environmental legislation

in

the

country. Bring out the specific features relevant W

water and air protection and those relating to forest

conservation.

8. a) Discuss about the estimation methods of

fixed

and

working capital requirement

f o ~

a process

15

15

1

4

industry.

2

b)

Explain about HAZOP and HAZAN.

2

B-JGT -J-OIFB

4 •

IFS Chemical Engineering 2009

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