3 ஐ

b)

00000CH405121902

i) Design a sieve tray tower operating at 1 atm. meeting all the
hydrodynamic considerations. (40)
ii) Give a neat sketch of the distillation column (10)

A cooling tower operates in the counter current mode, process hot water entering

at 48°C and the cold water leaves at 8°C approach to the wet-bulb temperature.
The entering air has a humidity of 0.001 kg/(kg dry air) and wet-bulb
temperature of 18°C. The cross-sectional area of the tower is 7 ൩. Determine the
height of the fill required for a tower operating with a liquid loading of 1700 kg-
H,O/(h)(m’) and an air loading of 1950 kg-air/(h)(m’). The overall mass transfer
coefficient, Kya is 2500 kg/(m*)(h).

A plant manufactures flue gas containing (02 by buming with air in a dryer.
Then the flue gases are cleaned & cooled. They contain 15% (02, 6% O» and
79% No. The gases are at 25°C, 912 mm Hg pressure. They are to be scrubbed
with 30% MEA solution to bring down the CO, content to 2% (02. Solvent,
50% in excess enters the column at 25°C and containing 0.058 mol of (02/ mol
of MEA solution. The scrubber is to be operated at 25°C and 912 mm Hg.
Determine number of transfer units and the diameter required for a packed

column to handle 100 tons per day of flue gases. The equilibrium data is as

follows.

Mol | 0.05
mol MEA,

Xx

Mol CO,/
mol(O7+N>),
Y

0.00618 | 0.01423 | 0.0328 | 0.0654 | 0.1213 | 0.2047 | 0.3411

नैनः नैनः

(25)

(25)

(2 x50= 100 Marks)

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