IFS Chemical Engineering 2001
Paper I

Section A
1. Answer any four of the following (10 × 4 40)
a. Explain free settling and hindered settling. What is the functional relationship between terminal velocity and particle size?
b. What are enthalpy-concentration diagrams? How do you construct it?
c. What do you understand by primary nucleation and secondary nucleation during crystallization?
d. Explain critical thickness of insulation. How do you find it for cylindrical shapes? Assume the thermal conductivity of the insulation as k. Heat transfer coefficient is h.
e. Define the following:
I. Mixing index for granular solids
II. Sphericity
III. Relative volatility
IV. Emissivity
2. Answer the following: (10 × 4 40)
a. Explain briefly about random packings used in packed towers. What are the characteristics considered during their selection?
b. Differentiate between skin drag and form drag. Where do they exist and under what conditions?
c. Describe the differential and cumulative screen analyses.
d. Compare the venturi meter and orifice meter.
3. Answer the following questions
a. Derive the Fenske equation to calculate the minimum number of plates in distillation
b. Explain a mixer-settler extraction system
c. Discuss the experimental measurement of diffusivity in a binary system
4. Answer the following questions
a. Estimate the heat transfer coefficient using available empirical correlation for the following case: A lubricating oil is flowing through a long smooth tube of 25 mm inside diameter. The inlet and outlet oil temperatures are 21° C and 55° C. The average wall temperature is assumed to be 65° C. The Reynolds number for the prevailing flow conditions has been found to be 10020. Data: At the average temperature, oil has Viscosity 31 cp Specific heat 1.88 kJ/kg K Specific gravity 0.91 Thermal conductivity 0.123 W/m K Viscosity at 65° C 12 cp Any missing data may be suitably assumed with justification
b. Discuss the method of estimation of the radiant heat duty of an oil fired furnace
c. Describe the different methods of feeding a multiple effect evaporator

Section B
1. Answer any four of the following: (10 × 4 40)
a. Explain about ultra filtration.
b. Write briefly on the dielectric method of level measurement.
c. Write the stepwise procedure for the design of a 1 elliptical head.
d. Describe the flapper-nozzle assembly used in process control.
e. Describe the procedure for the design of sampled data controllers.
2. Answer the following questions
a. For membrane processes, explain about
I. Dependence of permeability on temperature and its prediction
II. Membrane selectivity
b. Explain about the following:
I. Commercial dialyzers
II. Membranes for dialysis
c. What is Pervaporation? Elaborate
3. A flat-bottomed vertical cylindrical tank having a conical roof is to be designed for storing a petroleum product having a specific gravity of 0.8. The capacity of the storage tank should be 250 m3. Assume height to diameter ratio as unity. The width of the plate to be used for each course is 1.8 m. The allowable stress value of the material of construction is 14 kg/mm2. Assume a weld joint efficiency factor of 0.85. Determine the thickness required for each course of the cylindrical shell of the storage tank
4. Answer the following: (10 × 4 40)
a. Describe the electromagnetic flow meter. What are their advantages and limitations?
b. Find the frequency response (AR and phase angle) of a proportional integral controller. Give a sketch of the Bode diagram of the same.
c. Write briefly on Feed forward control.
d. What axe the elements of a computer control system? Explain briefly