Indian Institute of Technology Kharagpur (IIT-K) 2007 B.Tech Chemical Engineering Multiphase aration process - Question Paper
Chemical Engineering Department, Indian Institute of Technology Kharagpur
Mid-Autumn Semester Examination for Multiphase Separation Processes (CH34005) Wednesday, 19^{th} September, 2007, 1400-1600 hours (Total Marks = 100) Instructions to examinees:
1. ALL questions are mandatory.
2. To-the-point, concise, and brief answers are expected.
3. Neat and labeled schematic diagrams are ESSENTIAL for ALL answers.
Q. No. |
Question Description |
marks |
1. |
Under what condition are the mass average velocity and molar average velocity of all the components of a mixture are equal? |
2 |
2. |
Under what conditions does the diffusivity of the component / (Dj,_{m}) in a milticomponent gas mixture remain constant over entire the length of the diffusion path? |
2 |
3. |
Consider two cases: (i) Diffusion of A through non-diffusing B, and (ii) equimolar counterdiffusion of A and B. The respective fluxes are given by the following equations (in the usual notation): DP p - p _{(i) N =} -AJ AL - ^{R 1} ' (^{p}bl - "J '"("m "J |
4 5 |
D (p - p ) (ii) N = ^{AB V A} ^{A1} ' A R 1 L In which of the above two cases is N_{A} larger? Explain logically. | ||
4. |
Give one example each of: (i) mechanical separation, (ii) diffusional separation. |
2 |
5. |
Give two salient characteristics each of: (i) purely diffusional mass transfer, (ii) convective mass transfer. |
4 |
6. |
Derive the basic equation for steady state molecular diffusion through a C . dC constant area in a binarv 2as mixture: n =-im + n j - d . * . - ^{J} A ( V A B / AB |
6 |
7. |
Explain the assumptions involved in the film model derivation of flux. |
3 |
8. |
D . v Derive the film model equation: N = (<: - ( I. A g \ A, A, Bulk/ |
6 |
9. |
Write the assumptions involved in the derivation of flux using Higbies penetration theory. |
3 |
<> |
State the governing equation for the flux using Higbies penetration theory, and explain the three initial + boundary conditions needed for the solution. |
> 5 |
11. |
Qualitatively explain the concept of surface renewal rate in Danckwerts surface renewal theory. |
3 |
12. |
What is an operating line ? How does it differ from equilibrium line ? |
2 |
For interphase mass transfer, derive the expression:~ = + . K k k |
4 | |
13. |
Qualitatively (in terms of the driving forces) explain the difference between Ky and k_{y}. |
2 |
14. |
What is an Equilibrium / Ideal / Theoretical stage with respect to interphase mass transfer? |
2 |
15. |
Explain the term stage efficiency with respect to interphase mass transfer. |
3 |
- T c^{-}
VeWt
| ||||||||||||||||||||||||||||||||||||||||||||||||||
* |
Page 2 of2
Attachment: |
Earning: Approval pending. |