8HW Computer Aided Design - April 2000

Part A (20 x 2 = 40 Marks)

1. Explain briefly the elements of a digital computer
2. What are the different operating systems used in computer?
3. What does Hierarchy mean in computer operations?
4. What are the various input devices?
5. Explain the term 'assembly language'
6. State the various thermodynamic properties of a binary mixture
7. When do you use steam distillation?
8. Explain briefly the use of vapor-liquid equilibrium data
9. Explain how do you estimate the density of a gas mixture
10. Define the term entropy and enthalpy
11. Graphically represent how temperature profile varies with distance in a counter-current heat exchanger
12. Define the term 'relative volatility' and indicate its importance in the design of distillation columns
13. Explain the term limiting liquid to gas ratio in a stripper
14. Define the term logarithmic mean temperature
15. State the advantage of using backward feed multiple effect evaporators over forward feed units
16. Explain briefly how minimum reflux ratio is determined in a distillation operation
17. State the assumptions made in McCabe-Thiele method of estimating the number of stages in a distillation column
18. Define the term 'number of transfer units' and 'height of transfer units' in a packed column absorber
19. Suggest what type of absorber do you use for absorbing hydrochloric acid gas
20. State the factors to be considered in the selection of a solvent for the given extraction operation

Part B (5 x 12 = 60 Marks)

21. (a) Explain in detail the Central Processing Unit. Write in detail how it works.

Or

(b) Explain in detail the different components of a computer and state the different chemical engineering software available

22. (a) Develop an algorithm for the determination of vapor liquid equilibrium data for non-ideal mixtures and to check the thermodynamic consistency

Or

(b) Write the program for estimating the molal volume of an alcohol vapor using Redlich-Kwong equation of state

23. (a) A warm stream enters a heat exchanger at 200oC and is cooled to 100oC. The cooling stream enters at 20oC and is heated to 95oC. Write a program to calculate the mean temperature difference for the following cases: (i) Countercurrent flow, (ii) 1-2 multi-pass and 1-2 cross flow

Or

(b) Develop an algorithm for the determination of overall heat transfer coefficient for a shell and tube heat exchanger.

24. (a) Explain briefly the industrial applications of evaporators and write a program for the design of a multiple effect evaporator. Indicate clearly the different steps involved in the mass and energy balances

Or

(b) Develop an algorithm for the design of a short tube calendria evaporator

25. (a) Write a program to estimate the number of stages for absorption of a dilute gas stream using Kremser-Brown equation.

Or

(b) Develop an algorithm for the determination of height of a packed column for a distillation column.