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This section includes 908 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
1. |
With increase in temperature drop (in a shell and tube heat exchanger), the correction factor, |
A. | decreases very rapidly |
B. | increases very rapidly |
C. | remains constant |
D. | increases linearly |
Answer» B. increases very rapidly | |
2. |
In a double pipe concentric heat exchanger, the equivalent diameter of annulus for heat transfer would be (where, and are I.D. of inner and outer pipes) |
A. | - |
B. | none of these |
Answer» B. none of these | |
3. |
Joint efficiency () for a seamless pipe is |
A. | 1 |
B. | 0.85 |
C. | 1.2 |
D. | < 0.5 |
Answer» B. 0.85 | |
4. |
In common bubble cap distillation column design practice, riser area is approximately equal to (where, = Annular passage area, and = Slot area) |
A. | = |
B. | 1.2 |
C. | = 1.2 |
D. | = 1.5 |
E. | = 1.5 |
Answer» B. 1.2 | |
5. |
The absorption factor is defined as (where, = slope of the equilibrium curve, = slope of the operating line) |
A. | / |
B. | . |
C. | / |
D. | 1/ |
E. | . |
Answer» B. . | |
6. |
In the design of a paddle agitator, the ratiois normally taken as |
A. | 0.1 |
B. | 0.8 |
C. | 0.25 |
D. | 0.5 |
Answer» C. 0.25 | |
7. |
Stress-strain diagram for low carbon steel/mild steel is shown below in the Fig. The point '' on the Fig. represents the |
A. | breaking stress |
B. | ultimate stress |
C. | elastic limit |
D. | yield point |
Answer» D. yield point | |
8. |
In a multiple effect evaporator system having '' effects, the amount of water evaporated per unit surface area in approximately equal to __________ times that in a single effect. |
A. | 'n'th |
B. | (1/n)th |
C. | 0.5 nth |
D. | 1.5 nth |
Answer» C. 0.5 nth | |
9. |
The correction factor () is applied in __________ heat exchangers. |
A. | 1-1 cocurrent |
B. | double pipe |
C. | all multipass |
D. | all (involving liquid/liquid heat transfer) |
Answer» D. all (involving liquid/liquid heat transfer) | |
10. |
for couplings and unions would be |
A. | 60 |
B. | 200 |
C. | 350 |
D. | negligible |
Answer» E. | |
11. |
The equivalent diameter for fluid flow through a channel of constant non-circular cross section of area '' is given by (where, = perimeter of the channel in contact with the fluid) |
A. | 4 |
B. | / |
C. | / |
D. | 4 |
E. | / |
Answer» B. / | |
12. |
The raio, is normally taken as |
A. | 0.15-030 |
B. | 0.5-0.65 |
C. | 0.75-0.85 |
D. | 0.60-0.90 |
Answer» B. 0.5-0.65 | |
13. |
For pipe flows, head is proportional to __________ at constant capacity (where = pipe diameter ). |
A. | 1/ |
B. | 1/ |
C. | 1/ |
Answer» D. | |
14. |
Friction factor for turbulent flow in a new pipe is given by |
A. | = 0.22 |
Answer» C. | |
15. |
The approximate liquid depth in an agitation tank is equal to (where, = tank diameter) |
A. | 0.5 |
B. | 0.75 |
C. | 2 |
Answer» D. | |
16. |
A cylinderical pressure vessel of volume 6 πm has to be designed to withstand a maximum internal pressure of 10 atm. The allowable design stress of the material is 125N/mm and corrosion allowance is 2 mm. The thickness of the vessel for a length/diameter ratio of 3 will be close to |
A. | 5 mm |
B. | 6 mm |
C. | 8 mm |
D. | 10 mm |
Answer» E. | |
17. |
What is the value of '' for saturated vapor feed to a distillation column ?(where = fraction of the feed stream that is liquid.) |
A. | 0 |
B. | 1 |
C. | <0 |
D. | > 1 |
Answer» B. 1 | |
18. |
In case of plain carbon steel, butt welded joints are used for shell plate thickness ≤ __________ cms. |
A. | 1.2 |
B. | 0.5 |
C. | 3.8 |
D. | 6.8 |
Answer» D. 6.8 | |
19. |
In case of a shell and tube heat exchanger, the effect of / on inside film heat transfer co-efficient () vanishes after a Reynold number of |
A. | 1000 |
B. | 3000 |
C. | 5000 |
D. | 10000 |
Answer» E. | |
20. |
Souders Brown equation given by, , is used for the calculation of the __________ in a continuous distillation column. |
A. | diameter of the bubble cap column |
B. | diameter of the seive plate column |
C. | tray pressure drop |
D. | residence time in the downcomer for the disengagement of entrained vapour |
Answer» B. diameter of the seive plate column | |
21. |
The safe height () to diameter () ratio (i.e., /) for liquid/petro fuel storage tank of capacity more than 45 kilolitres is less than |
A. | 1 |
B. | 2 |
C. | 3 |
D. | 3.5 |
Answer» B. 2 | |
22. |
Steam is defined as the amount of evaporation per unit amount of steam used, while the is the total evaporation obtained per hour. Use of multiple effect in evaporation |
A. | increases capacity. |
B. | increases economy. |
C. | does not affect the capacity. |
D. | both 'b' & 'c'. |
Answer» E. | |
23. |
Elastic failure of a material occurs, when the tensile stress equals yield strength, yield point or the elastic limit. Also, the elastic failure occurs according to maximum strain theory, when the maximum tensile strain equals (where, σ = yield strength and = modulus of elasticity) |
A. | σ |
B. | σ/ |
C. | /σ |
Answer» D. | |
24. |
Diameter of rivet hole (, mm) and the plate thickness (, mm) are related by Unwin's formula as |
A. | = 1.1 |
B. | = 1.6 |
C. | = 1.5 |
D. | 3 |
Answer» C. = 1.5 | |
25. |
Heat transfer co-efficient, (K/hr.m .°C) and mass velocity of air, (kg/hr.m ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as = 0.0176. But when the flow of air perpendicular to the surface is encountered, this equation changes to |
A. | = 1.004 |
B. | 1.004 |
C. | hG = 0.0176 |
D. | 0.0176 |
Answer» B. 1.004 | |
26. |
In a shell and tube heat exchanger having square pitch, the shell side equivalent diameter is given by (where, = pitch, = outside diameter of the tube) |
A. | π |
B. | /4 |
Answer» B. /4 | |
27. |
Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, = shell diameter ) |
A. | 0.2 |
B. | 0.5 |
C. | 0.66 |
D. | 0.80 |
Answer» B. 0.5 | |
28. |
Pressure drop due to pipe fittings can be estimated by the equation, , where, = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and = diameter of the fitting. The value of (dimensionless) for 45° elbow and 180° close return bends would be respectively around |
A. | 5 and 10 |
B. | 45 and 75 |
C. | 180 and 300 |
D. | 300 and 500 |
Answer» C. 180 and 300 | |
29. |
In a shell and tube heat exchanger, the overall heat transfer co-efficient is proportional to the tube side (volumetric flow rate). This is valid, only when the ratio of the tube side film resistance to the total resistance is almost equal to |
A. | ∞ |
B. | 1 |
C. | 20.8 |
D. | 2 |
Answer» C. 20.8 | |
30. |
Pick out the wrong statement.In an agitated vertical cylinderical reaction vessel, the |
A. | ratio of liquid depth to tank diameter (i.e. the filling ratio) recommended for most purposes is 1. |
B. | filling ratio for dispersing gas in a liquid is 2 for sufficiently long contact period. |
C. | flat bottom and conical bottom vessels have low agitation efficiency for agitation of heavy solids in liquids. |
D. | dished bottom vessel has very high power consumption. |
Answer» E. | |
31. |
What is the value of '' for saturated liquid feed to a distillation column ? |
A. | 0 |
B. | <1 |
C. | 1 |
D. | >1 |
Answer» D. >1 | |
32. |
Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m.°C. |
A. | 1250 |
B. | 2500 |
C. | 7500 |
D. | 15000 |
Answer» D. 15000 | |
33. |
It is not desirable to design a heat exchanger for correction factor, , of less than |
A. | 0.99 |
B. | 0.95 |
C. | 0.80 |
D. | 0.55 |
Answer» D. 0.55 | |
34. |
Overall distillation column efficiency for most of the refinery columns can be given by (for μ = 0.07 - 1.4 cp and relative volatility < 4) (where η = overall column efficiency, % μ = molal average viscosity of feed at average column temperature and pressure, cp Δ = pressure drop per tray, psi) |
A. | η = 17 - 61.1 log μ |
B. | η = 1.66 - 0.25 log μ |
C. | η = 0.25 log μ - 1.67 |
Answer» B. η = 1.66 - 0.25 log μ | |
35. |
With increase in the number of shell passes, the value of |
A. | increases |
B. | decreases |
C. | remains same |
D. | remains same, only if the number of tube passes does not change. |
Answer» B. decreases | |
36. |
A cylinderical pressure vessel of volume 6 πm3 has to be designed to withstand a maximum internal pressure of 10 atm. The allowable design stress of the material is 125N/mm2 and corrosion allowance is 2 mm. The thickness of the vessel for a length/diameter ratio of 3 will be close to |
A. | 5 mm |
B. | 6 mm |
C. | 8 mm |
D. | 10 mm |
Answer» E. | |
37. |
In a cylinderical vessel subjected to internal pressure, the longitudinal stress σL and the circumferential stress, σn are related by |
A. | σh = 2 σL |
B. | σh = σL |
C. | σh = σL/2 |
D. | no relation exists |
Answer» B. σh = σL | |
38. |
Heat transfer co-efficient, hG(Kcal/hr.m2 .°C) and mass velocity of air, G (kg/hr.m2 ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to |
A. | hG = 1.004G0.37 |
B. | 1.004G0.8 |
C. | hG = 0.0176G0.37 |
D. | 0.0176G1.37 |
Answer» B. 1.004G0.8 | |
39. |
Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m2.°C. |
A. | 1250 |
B. | 2500 |
C. | 7500 |
D. | 15000 |
Answer» D. 15000 | |
40. |
In a rotary drier, the average retention time of solid is(where Z = length of the drier, metres ρ = apparent solid density, kg/m3 L = flow rate of dry solids, kg/see. m2 drier cross-section H = hold up of solid.) |
A. | [A]. |
B. | [B]. |
C. | [C]. |
D. | [D]. |
Answer» B. [B]. | |
41. |
For turbulent flow (NRe > 2100) of low viscosity fluid (μ > 20cp) in steel pipes, the optimum inside pipe diameter is given by(where, Q = fluid flow rate, ft3/sec.ρ = fluid density, lb/ft3 μ = fluid viscosity, centipoise Di = optimum inside pipe diameter, inches) |
A. | Di, opt = 3.9 Q0.45 ρ0.13 |
B. | Di, opt = 3.9 Q0.45 . μ0.95 |
C. | Di, opt = 4.7 Q0.36 . μ3.2ρ0.13 |
D. | Di, opt = 3 Q0.36 . μ0.88 |
Answer» B. Di, opt = 3.9 Q0.45 . μ0.95 | |
42. |
for 90° elbow (medium radius) and 90°square elbow would be respectively around |
A. | 25 and 60 |
B. | 3 and 5 |
C. | 100 and 250 |
D. | 250 and 600 |
Answer» B. 3 and 5 | |
43. |
Pressure drop due to pipe fittings can be estimated by the equation, , where, Le = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of (dimensionless) for 45° elbow and 180° close return bends would be respectively around |
A. | 5 and 10 |
B. | 45 and 75 |
C. | 180 and 300 |
D. | 300 and 500 |
Answer» C. 180 and 300 | |
44. |
In case of plain carbon steel, butt welded joints are used for shell plate thickness ≤ __________ cms.. |
A. | 0.2 |
B. | 0.5 |
C. | 0.8 |
D. | 0.8 |
Answer» D. 0.8 | |
45. |
Pressure drop due to pipe fittings can be estimated by the equation, ΔP/p = 4f.Le/D.V2/2gc, where, Le = equivalent length of straight pipeline which will incur the same frictional loss as the fitting and D = diameter of the fitting. The value of Le/D (dimensionless) for 45° elbow and 180° close return bends would be respectively around |
A. | and 10 |
B. | 5 and 75 |
C. | 80 and 300 |
D. | 00 and 500 |
Answer» C. 80 and 300 | |
46. |
Which of the following factors affect the pressure drop in a co-current gas-liquid absorption packed tower? |
A. | ize, shape, orientation and surface of the packing particles |
B. | ensity and viscosity of fluids |
C. | luid flow rates |
D. | ll of the above |
Answer» E. | |
47. |
The centre to centre distance between two consecutive baffles in a shell and tube heat exchanger is called the baffle pitch or baffle spacing, which is more than 1/5th the I.D. of the shell. Which of the following is not a function of the baffles? |
A. | o increase the residence time of shell side fluid |
B. | o provide support to the tube bundle |
C. | o reduce the induced vibration in the tubes |
D. | o increase the tube side heat transfer co-efficient by inducing turbulence |
Answer» E. | |
48. |
The clearance between two tubes in a shell and tube heat exchanger is known as 'ligament', whose minimum value is __________ the outside diameter of the tube, but in no case it should be less than 4.5 mm. |
A. | qual to |
B. | alf |
C. | ne fourth |
D. | hree fourth |
Answer» D. hree fourth | |
49. |
For a cylinderical vessel of moderate height, the weld joint efficiency for joints parallel to the cylinderical axis is given as 1.0, while for joints along the girth (circumference) it is given as 0.8. In calculating the shell wall thickness using code formula for an internally pressurised cylinderical vessel, what value of weld joint efficiency should be used? |
A. | 0.8 |
B. | 0.9 |
C. | 0 |
D. | 0.8)0.5 |
Answer» B. 0.9 | |
50. |
Heat transfer co-efficient, hG(Kcal/hr.m² .°C) and mass velocity of air, G (kg/hr.m² ) for air flow parallel to the surface in case of constant drying rate in batch drying is related as hG = 0.0176G0.8. But when the flow of air perpendicular to the surface is encountered, this equation changes to |
A. | G = 1.004G0.37 |
B. | .004G0.8 |
C. | G = 0.0176G0.37 |
D. | .0176G1.37 |
Answer» B. .004G0.8 | |