Mass Transfer Operation - 2 Question Paper - May 2016 - Chemical Engineering (Semester 6)

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Mass Transfer Operation - 2 - May 2016

MU Chemical Engineering (Semester 6)

Total marks: --
Total time: -- INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary 1(a) Define q factor is distillation and give its significance. 4 marks

1(b) Discuss the selection criteria for solvent liquid-liquid extraction. 4 marks

1(c) Explain the factors affecting leaching operation. 4 marks

1(d) Give the properties of adsorbents. 4 marks

1(e) State and explain the &Delta 4 marks

2 For a binary system of heptane-ethylbenzene the equilibrium data are as follows:

x	0	0.08	0.185	0.251	0.333	0.487	0.651	0.788	0.914	1
y	0	0.233	0.428	0.514	0.618	0.729	0.834	0.904	0.963	1

A feed mixture composed of 42 mole% heptane and 58 mole% ethyl benzene is to be fractionated to yield an overhead product of 197 mole% heptane and a residue of 99 mole ethyl benzene.
(i) Using reflux ratio of 1.5 find the number of equilibrium stages needed for saturated liquid feed and a bubble point reflux by the McCabe-Thiele method.
(ii) Find the minimum reflux ratio.
(iii) Find the number of equilibrium stages at total reflux. 4 marks

3(a) Give the procedure to find the height of packed bed for liquid-liquid extraction tower. 4 marks

3(b) Derive Fenske's equation for minimum no. Of stages at total reflux. 4 marks

4(a) Explain the construction and working of Bollmann extractor. 4 marks

4(b) For extraction of dioxane from water, benzene is used as an extraction solvent. At 298K, the equilibrium distribution of dioxane between water and benzene is as given below:

Weight % dioxane in water	5.1	18.9	25.2
Weight % dioxane in benzene	5.2	22.5	32

At these concentrations, water and benzene are substantially insouluble 1000kg of solution containing 25% dioxane is to be extracted with benzene to remove 95% of the dioxane free benzene is used.
(i) calculate the solvent requirement for single batch operation.
(ii) If the extraction were done: in four stages cross current unit using 750 kg of pure benzene each time, determine the final raffinate concentration and the percentage removal of dioxane from feed solution. 4 marks

5(a) Discuss the adsorption in fixed beds. Explain break through curve and adsorption zone. 4 marks

5(b) A hot solution of 5000kg containing Na₂CO₃ and water with a concentration of 25% by weight Na₂CO₃ is cooled to 20° 4 marks

Write short notes on any Four out of following

6(a) Minimum and maximum boiling azeotropes. 4 marks

6(b) Ion Exchange 4 marks

6(c) Hollow and spiral wound membranes 4 marks

6(d) Reverse osmosis 4 marks

6(e) Oslo cooling crystallizer 4 marks

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