Process Equipment and Plant Design problems
- 1. Overall distillation column efficiency for most of the refinery columns can be given by (for ? = 0.07 - 1.4 cp and relative volatility < 4) (where ? = overall column efficiency, % ? = molal average viscosity of feed at average column temperature and pressure, cp ?p = pressure drop per tray, psi)
Options- A. ? = 17 - 61.1 log ?
- B.
- C. ? = 1.66 - 0.25 log ?
- D. ? = 0.25 log ? - 1.67 Discuss
Correct Answer: ? = 17 - 61.1 log ?
- 2. Smaller sized packings are generally dumped to the packed columns, and the large ones of size greater than __________ mm are stacked individually, which provides better control over bed porosity and offers lower gas pressure drop.
Options- A. 25
- B. 50
- C. 75
- D. 150 Discuss
Correct Answer: 75
- 3. Fresh water carrying pipelines in chemical industries are coloured with __________ color.
Options- A. sea green
- B. brown
- C. yellow
- D. red Discuss
Correct Answer: sea green
- 4. 25 per cent cut segmental baffle means that the baffle
Options- A. height is 75% of the I.D. of the shell.
- B. height is 25% of the I.D. of the shell.
- C. spacing is 75% of its height.
- D. width is 25% of its height. Discuss
Correct Answer: height is 75% of the I.D. of the shell.
- 5. The ratio of shear stress to shear strain is called
Options- A. bulk modulus
- B. shear modulus
- C. modulus of rigidity
- D. modulus of elasticity Discuss
Correct Answer: shear modulus
- 6. Pick out the wrong statement pertaining to the use of valve tray, seive tray and bubble cap trays in continuous distillation column.
Options- A. Bubble cap trays though most expensive are the best in situations, where low vapour rates is to be handled and a positive liquid seal is essential at all flow rates.
- B. Murphree efficiency of all the three trays are nearly equal, however the peak efficiency is generally higher for seive and valve trays than the bubble cap.
- C. Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features.
- D. Valve trays have the highest turn down ratio (i.e. the ratio of the highest to the lowest vapour flow rates) and thus provides the maximum flexible operating range. Discuss
Correct Answer: Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features.
- 7. Correct use of 'factor of safety' is very important in equipment design. It is defined as the ratio of the
Options- A. ultimate stress to breaking stress.
- B. ultimate stress to working stress.
- C. working stress to ultimate stress.
- D. none of these. Discuss
Correct Answer: ultimate stress to working stress.
- 8. Pick out the wrong statement pertaining to the design of the bubble cap tray of a distillation column to give stable operation and even vapour distribution.
Options- A. The pressure drop due to the caps & slots and the static submergence should be as high as practicable for reasonable operation.
- B. Tendency towards stable operation is increased by increasing the skirt clearance of the caps, lowering the rate of liquid flow per unit plate width or increasing the spacing between the caps.
- C. The dimensionless ratio of liquid gradient to pressure drop head caused by the bubble cap assembly should be less than 0.4.
- D. none of these. Discuss
Correct Answer: none of these.
- 9. It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than
Options- A. 0.99
- B. 0.95
- C. 0.80
- D. 0.55 Discuss
Correct Answer: 0.80
- 10. Bracket supports are the most suitable for supporting __________ vessels.
Options- A. thick walled vertical
- B. horizontal
- C. thin shperical (e.g. Horton sphere)
- D. none of these Discuss
Correct Answer: thick walled vertical
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