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NDIAN INSTITUTE OF TECHNOLOGY, KHARAGPUR

End-Spring

Semester Examination, 2012-2013

Subject: Chemical Process Technology Subject No : CH 30014

Date: 17.04.2013 (AN) Time: 3 Hrs Full Marks: 60

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5

,.a

Instructions : Use same ANSWER BOOK for Part A and Part B.

Do not ask for clarification on any question. State and assume any missing data suitably.

PART- A [Answer Alrf QUESTIONS OUT OF

Ql

TO Q5]

Q1a. A naphtha based fertilizer plant produces urea [CO(NH

2

)

2

]. The feed naphtha having 18%

wlw H

2

has a density of 730 Kg/M

3

• This plant receives naphtha in railway wagons with

unloading capacity of 1200 M

3

1day. Estimate the maximum daily production of ammonia

in the ammonia production section of this plant. (Atomic weights ofN 0 and Hare 14,

16

and

1 .

[12 marks]

Q2a. List the potential pollutants from fillY specific chemical industry of your choice- include

solid, liquid and gaseous wastes effluents emissions. Describe the treatment process for

only the liquid effluent with a process flow diagram and its description. [2+5:::;7 marks]

Q2b. Explain why in manufacture of liquid nitrogen and oxygen in an air separation plant all

modern plants use the 'double-column' configuration. [5 marks]

Q3. A naphtha cracker is producing a stream with same molar proportion of ethylene and

acetylene. The recoveries of these components are both 98%. t is decided to produce

vinyl chloride from both these components in two plants. Chlorine is available as a raw

material from the caustic - chlorine plant within the chemical complex. What will be the

optimum ratio of vinyl chloride production capacity of these two plants considering 95%

yield in each process stage? [12 marks]

Q4.

Above figure shows the reactor section of an ammonia plant fed with fresh feed consisting

of 1000 kmollhr ofNz+Hz. In addition it also has 2 kmol hr argon. In the reactor 25% of

the Nz+H

2

fed is converted to ammonia that gets condensed and separated as liquid

ammonia stream. Exit gas from separator contains unconverted reactants, part of which is

recycled and the rest is purged out. The reactor feed must not contain more that 5 moles of

argon per mole ofN2+Hz entering reactor. Find (a) the production rate of liquid ammonia

in kmollhr, (b) reactor inlet total flow rate at minimum purge flow rate. [9+3=12 marks]

Q5. Bangladesh has proposed exporting natural gas to India. Write a brief technical note with

accompanying process block flow diagrams outlining the routes for the petrochemicals

you suggest to be manufactured in a petrochemical complex at Haldia. [12 marks]

End of Part A

Continued 2 2

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Q6

(a)

(b)

(c)

d)

(e)

(f)

g)

h)

(i)

1:;:

(j)

k)

(I)

m)

Page 2/2

PART B [AnswerQ. NO 6]

Answer in brief

any 12

from the followipg (12

X

1 = 2 marks)

Why for production

of

BTX by catalytic reforming

of

naphtha the feedstock is chosen to

be lighter (lower boiling range) than that for producing high octane reformate?

The step

of

'Xanthation'

is

used in manufacture

of

which synthetic product starting from

cellulose? What

is

this step?

Why do all plants producing super phosphate fertilizer in India have sulphuric acid plants

in their factory?

Which type

of

mixer

is

used to mix the powdered additives (carbon black, calcium

carbonate etc.) with raw rubber during its processing?

Natural gas contains both C02 and

H2S

as impurities. How are these removed?

What's 'b lack liquor'?

State two typical characteristics

of

Indian crude oil.

Apart from raw material, which is the largest operating cost component in a cement plant?

What's an atactic polymer?

Which are the f lajor pollutants present in the liquid effluent from a viscose rayon plant?

What are the specific differences between a 'block flow diagram' and a 'process flow

diagram'?

Why the products from a petroleum refinery called co-products

of

refining?

In a mixed fertilizer grade

5 l 0-5,

what

is

the weight fraction

of

the

element l

potassium

present in it?

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