Reg No. 00000CH4051219)'nme:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

Seventh semester B.Tech examinations (S), September 2020

Course Code: CH405
Course Name: CHEMICAL ENGINEERING DESIGN II
Max. Marks: 100 Duration: 3 Hours

Instructions:

1. Graph sheets may be provided
2. Missing data may be assumed suitably
3. The following materials are allowed in the examination:
i. Perry’s Chemical Engineers Hand book (original print and attested photocopies),
McGraw-Hill Int. Edn.
ii. Steam Table (original print), IS Codes, Psychrometric chart.
iii. Attested copies of relevant equations and charts for design of sieve tray from ‘Mass
Transfer Operations’ by Robert E. Treybal (pages 169, 532 to 538), McGraw-Hill
Int. Edn
The attestation must be done by the concerned faculty engaging the subject with official seal.

Answer any two full questions, each carries 50 marks. Marks

1 a) A rotary dryer is fed with granulated fertilizer simple super-phosphate (SSPG) at (50)
a flow rate of 1.2 kg/s., with average diameter of 2.45 mm, initial moisture
content 0.15 kg water/kg dry solid, specific mass of 1.1 kg/m’ and specific heat
0.245 kcal/kg dry solid. °C. The solid is to be dried to 0.001 kg water/kg dry solid
at a temperature of 120 °C. It will be dried by hot air entering at 155°C, 0.01 kg
water/kg dry air. Design the dryer with all essential parts.

[2

a) 92% ௦4180 from air is to be absorbed using water at 25°C in a packed tower. The (50)
inlet air flow rate is 200m*/hour at latm pressure with 14% 502. By neglecting
any heat effects and assuming that water flow rate used is 1.5 times the minimum
required rate, calculate the diameter of the tower. Equilibrium relationship is

y*=35x where y and x are the mole fractions 01502 in air and water respectively.
(i) Design an appropriate packed tower. (40)
(ii) Sketch the packed column. (10)

3 8) A short tube evaporator is used to concentrate 4500 kg/h of a 20% solution of (25)
MgCl) in water entering at 60°C to a product of 50% solids. The pressure of the

saturated steam used is 170 kPa and the pressure in the vapour space of the

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