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Question 1

1. Fresh water carrying pipelines in chemical industries are coloured with
   _______ color.
   a. sea green
   b. brown
   c. yellow
   d. red

Answer 1

a. sea green

Question 2

2. Which of the following material is seldom used for pressure vessel
   construction ?
   a. Rimmed still
   b. Mild steel
   c. Killed steel
   d. Semi-killed steel

Answer 2

a. Rimmed still

Question 3

3. The ratio of shear stress to shear strain is called
   a. bulk modulus
   b. shear modulus
   c. modulus of rigidity
   d. modulus of elasticity

Answer 3

b. shear modulus

Question 4

4. 25 per cent cut segmental baffle means that the baffle
   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.

Answer 4

a. height is 75% of the I.D. of the shell.

Question 5

5. Liquid/petroleum fuel storage tanks are built underground (as in case of
   petrol pumps), when the storage capacity is less than ______ kilolitres.
   a. 20
   b. 30
   c. 45
   d. 85

Answer 5

c. 45

Question 6

6. Le/ D for fully open globe value may be around
   a. 10
   b. 25
   c. 75
   d. 300

Answer 6

d. 300

Question 7

7. Lug support is
   a. the most suitable for thick vertical vessel.
   b. same as bracket support.
   c. provided usually for vessels of much smaller height than skirt
   supported vessels.
   d. all (a), (b) and (c).

Answer 7

d. all (a), (b) and (c).

Question 8

8. Pick out the wrong statement pertaining to the use of valve tray, seive tray and bubble cap trays in continuous distillation column.
   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.

Answer 8

c. Maintenance cost for valve and seive trays are comparatively more
than bubble cap tray due to their relatively complicated construction
features.

Question 9

9. With increase in the number of shell passes, the value of FT
   a. increases
   b. decreases
   c. remains same
   d. remains same, only if the number of tube passes does not change.

Answer 9

a. increases

Question 10

10. Holes of a sieve tray are arranged in triangular pitch of __________ times the hole diameter.
    a. 1.5 to 2
    b. 2.5 to 5
    c. 5 to 10
    d. 10 to 15

Answer 10

b. 2.5 to 5

Question 11

11. In case of a shell and tube heat exchanger, the minimum shell thickness for carbon steel (inclusive of corrosion allowance) depends on shell diameter and is in the range of __________ mm.
    a. 3-5
    b. 5-11
    c. 8-15
    d. 12-18

Answer 11

b. 5-11

Question 12

12. The stress developed in a material without any permanent set is called the
    a. ultimate stress
    b. yield stress
    c. elastic limit
    d. breaking stress

Answer 12

c. elastic limit

Question 13

13. In a shell and tube heat exchanger, the ‘tube pitch’ is defined as the
    a. O.D. of the tube for square pitch.
    b. shortest distance between two adj acent tube holes.
    c. shortest centre to centre distance between adjacent tubes.
    d. none of these.

Answer 13

c. shortest centre to centre distance between adjacent tubes.

Question 14

14. Which of the following is not a valid assumption in continuous binary distillation for calculating the number of equilibrium stages by Mc-Cabe Thiele’s method ?
    a. Sensible heat changes for vapour & liquid are negligibly small.
    b. Reflux is not a saturated liquid.
    c. Molar latent heat of the two components are equal.
    d. Heat of mixing of normal liquid is assumed to be zero.

Answer 14

b. Reflux is not a saturated liquid.

Question 15

15. 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 Δp = pressure drop per tray, psi)
    a. η = 17 - 61.1 log μ
    b.
    c. η = 1.66 - 0.25 log μ
    d. η = 0.25 log μ - 1.67

Answer 15

a. η = 17 - 61.1 log μ

Question 16

16. The value of fouling factor depends upon the
    a. characteristic of process fluid.
    b. velocity of process fluid containing suspended solids.
    c. suspended solids in the fluid.
    d. all (a), (b) and (c).

Answer 16

d. all (a), (b) and (c).

Question 17

17. In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about __________ cms.
    a. 10
    b. 20
    c. 30
    d. 35

Answer 17

a. 10

Question 18

18. Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about __________ times, that in a 1-1 heat exchanger having the same size & number of tubes and operated at the same liquid flow rate.
    a. 2
    b. 1/2
    c. 4
    d. 8

Answer 18

d. 8

Question 19

19. To keep the power input constant for a stirred vessel operating under fully developed turbulent flow conditions (constant power number), if the impeller diameter is increased by 20%, the impeller speed should be decreased by a factor of
    a. (1.2)3/2
    b. (1.2)3/5
    c. (1.2)2/3
    d. (1.2)5/3

Answer 19

d. (1.2)5/3

Question 20

20. In a heat exchanger, shell side fluid velocity can be changed by changing
    the tube
    a. layout
    b. pitch
    c. both (a) & (b)
    d. neither (a) nor (b)

Answer 20

c. both (a) & (b)

Question 21

21. Where does the maximum tensile strength occur in a thick cylindrical vessel subjected to internal pressure ?
    a. At the inner surface.
    b. At the mid thickness of the cylindrical wall.
    c. At the outer surface.
    d. None of these.

Answer 21

a. At the inner surface.

Question 22

22. It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than
    a. 0.99
    b. 0.95
    c. 0.80
    d. 0.55

Answer 22

c. 0.80

Question 23

23. A rivetted joint does not fail by __________ of rivets.
    a. tearing
    b. shearing
    c. tearing of the plate across a row
    d. none of these

Answer 23

d. none of these

Question 24

24. Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger
    a. permits the use of less tubes in a given shell diameter.
    b. facilitates comparatively easier external cleaning because of large
    clearance.
    c. permits the use of more tubes in a given shell diameter.
    d. both (b) and (c).

Answer 24

c. permits the use of more tubes in a given shell diameter.

Question 25

25. Bracket supports are the most suitable for supporting __________ vessels. a. thick walled vertical b. horizontal c. thin shperical (e.g. Horton sphere) d. none of these

Answer 25

a. thick walled vertical

Question 26

26. In a multipass shell and tube heat exchanger, the shell side cross flow area does not depend upon a. baffle spacing b. clearance c. pitch d. none of these

Answer 26

d. none of these

Question 27

27. Two iron pipes of the same nominal diameter but different schedule numbers will have the same a. inside diameter b. outside diameter c. wall thickness d. none of these

Answer 27

a. inside diameter

Question 28

28. 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 28

c. 7500

Question 29

29. Pick out the wrong statement a. For all the cylindrical process vessels operating above atmospheric pressure, formed heads are used for closing the vessel. b. Fouling factor of river water is less than that of sea water. c. Risers provided in bubble cap trays in the distillation column facilitate the flow of both liquid and vapor. d. both (b) and (c).

Answer 29

d. both (b) and (c).

Question 30

30. Lessing ring is formed by the addition of a partition across the centre of a raschig ring, which results in an area increase of about __________ percent. a. 5 b. 20 c. 35 d. 55

Answer 30

b. 20

Question 31

31. In chemical process equipments, the conical bottom heads used, usually has an apex angle of a. 20° b. 40° c. 60° d. 80°

Answer 31

c. 60°

Question 32

32. 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. a. 25 b. 50 c. 75 d. 150

Answer 32

c. 75

Question 33

33. Shell side heat transfer co-efficient in case of square pitch as compared to the triangular pitch under similar condition of fluid flow and tube size is a. more b. same c. less d. twice

Answer 33

c. less

Question 34

34. Correct use of 'factor of safety' is very important in equipment design. It is defined as the ratio of the a. ultimate stress to breaking stress. b. ultimate stress to working stress. c. working stress to ultimate stress. d. none of these.

Answer 34

b. ultimate stress to working stress.

Question 35

35. The operating velocity in the absorption tower is usually 40-50% of the flooding velocity. Packed absorption towers are normally designed for a pressure drop of about __________ mm of water column per metre height of packing. a. 1-5 b. 20-40 c. 100-150 d. 1000-1500

Answer 35

b. 20-40

Question 36

36. __________ tray arrangement is recommended for distillation column having diameter upto 4 ft. a. Radial flow b. Cross flow c. Split flow d. Cascade

Answer 36

b. Cross flow

Question 37

37. What is the value of 'q' for saturated liquid feed to a distillation column ? a. 0 b. <1 c. 1 d. >1

Answer 37

c. 1

Question 38

38. In perforated plate towers, the a. hole sizes may be around 1/8" or 3/16". b. total hole area may be around 6 to 15% of tower cross-sectional area. c. pressure drop is less compared is similar bubble cap towers. d. all (a), (b) and (c).

Answer 38

d. all (a), (b) and (c).

Question 39

39. The main purpose of providing stepping on the trays is to a. increase the residence time. b. decrease the pressure drop. c. facilitate handling of large flow rate of liquid. d. improve the flow condition.

Answer 39

c. facilitate handling of large flow rate of liquid.

Question 40

40. The operating pressure drop range in a bag filter is about __________ mm water gauge. a. 50-150 b. 5-10 c. 500-1500 d. 1500-2500

Answer 40

a. 50-150

Question 41

41. The ends of a cylinderical vessel can be closed by a head, which can be one of the four shapes. For the same thickness, choose the one which can withstand the highest pressure. a. Flat plate b. Hemispherical c. Torispherical d. Ellipsoidal

Answer 41

d. Ellipsoidal

Question 42

42.For laminar flow (NRe < 2100) in steel pipe, the optimum inside pipe diameter is given by a. Di, opt = 3 Q0.36 ρ0.18 b. Di, opt = 3.9 Q0.45 . ρ0.23 c. Di, opt = 7.6 Q0.36 . ρ0.9 d. Di, opt = 3 Q0.36 . ρ1.86 μ0.08

Answer 42

a. Di, opt = 3 Q0.36 ρ0.18

Question 43

43. Pick out the correct statement. a. When highly corrosive fluids are to be handled, the plate towers prove to be cheaper and easier to construct than packed tower. b. Packed towers are generally preferred over plate towers, if the liquids have a foaming tendency. c. The pressure drop through the packed towers is generally more than the pressure drop through plate towers designed for same duty. d. none of these.

Answer 43

b. Packed towers are generally preferred over plate towers, if the liquids have a foaming tendency.

Question 44

44. Wall thickness of schedule 40 pipe as compared to that of schedule 80 pipe is a. more b. less c. same d. cither (a) or (b); depends upon the I.D. of the pipe

Answer 44

b. less

Question 45

45. Pick out the wrong statement pertaining to the design of a basket type evaporator. a. It is used for high viscosity liquor having large rate of scaling. b. The tube bundle is suspended on bracket. c. There is no central downtake. d. Downtake is formed by the annular space between the bundle and the shell.

Answer 45

a. It is used for high viscosity liquor having large rate of scaling.

Question 46

46. 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. 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.

Answer 46

d. none of these.

Question 47

47. Speed of the drum of the rotary vacuum filter normally ranges from __________ rpm. a. 0.1 to 2 b. 5 to 7 c. 3 to 8 d. 8 to 15

Answer 47

a. 0.1 to 2

Question 48

48. A stuffing box is used for a. absorbing the contraction/expansion of pipeline due to temperature changes. b. prevention of fluid leakage around moving parts. c. facilitating smooth opening and closing of a valve. d. reducing the resistance of fluid flow.

Answer 48

b. prevention of fluid leakage around moving parts.

Question 50

50. 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 50

d. dished bottom vessel has very high power consumption.

Question 51

1. Needle valves are generally not used for a. very large diameter pipes. b. high pressure throttling service. c. very accurate flow control. d. smaller sizes of pipe.

Answer 51

a. very large diameter pipes.

Question 52

2. Height equivalent to a theoretical plate (HETP) is the height of packing that will give the same separation as one theoretical plate in gas-liquid mass transfer operations like distillation, absorption/stripping and humidification/dehumidification. HETP which is experimentally determined, depends upon the a. flow rates of each fluid. b. type and size of packing. c. concentration of each fluid. d. all a, b & c.

Answer 52

d. all a, b & c.

Question 53

3. Pick out the wrong statement. a. Safety valves are provided in heat exchangers for removal of non conden-sables. b. Liquid metals and dowtherm are used for very high temperature heating. c. In a shell and tube heat exchanger, high pressure fluid is generally routed through the tube. d. A loop seal or U-seal is provided in a vertical condenser sub-cooler to prevent quick draining of the condensate.

Answer 53

a. Safety valves are provided in heat exchangers for removal of non conden-sables.

Question 54

4. With increase in gas flow rate to fabric surface area ratio (Nm3/hr/m2 fabric surface area), the size & the cost of a bag filter a. increases b. decreases c. remain unaffected d. none of these

Answer 54

a. increases b. decreases c. remain unaffected d. none of these

Question 55

5. A head comprises of straight flange section, corner torus, section and central dished section. Crown radius and knuckle radius in a head is related respectively to the a. central dished section and corner torus section. b. corner torus section and central dished section. c. central dished section and straight flange section. d. straight flange section and corner torus section.

Answer 55

a. central dished section and corner torus section.

Question 56

6. Number of evaporators which can be used in service in a multiple effect evaporation system is limited by the a. practical limit reached, due to low heat transfer rate because of inadequate temperature difference. b. economic limit reached, when the plant cost exceeds the saving of steam. c. both (a) & (b). d. neither (a) nor (b).

Answer 56

c. both (a) & (b).

Question 57

7. Which of the following is used to set the diameter of the distillation column? a. Number of theorectical plates. b. Static submergence. c. Allowable vapour velocity. d. Length of straight rectangular weir on cross-flow tray.

Answer 57

c. Allowable vapour velocity.

Question 58

8. Ponchon Savarit method is based on the use of enthalpy concentration diagram, which contains the bubble point curve (saturated liquid curve), dew point curve (saturated vapour curve) and equilibrium tie lines. As compared to McCabe-Thiele's method, this method a. is more accurate in finding the number of equilibrium stages. b. accounts for the enthalpy changes in the process. c. facilitates direct calculation of heat load on reboiler & condenser from, the diagram used in this method. d. all 'a', 'b' & 'c'.

Answer 58

d. all 'a', 'b' & 'c'.

Question 59

9. The optimum size ratio for two mixed reactors in series depends on the kinetics of the reaction and the conversion level. For reaction orders more than one, the a. equal sized reactors are the best. b. smaller reactor should come first. c. larger reactor should come first. d. none of these.

Answer 59

b. smaller reactor should come first.

Question 60

10. In a shell and tube heat exchanger, tube side __________ of the mass velocity. a. heat transfer co-efficient is proportional to 0.8th power b. pressure drop is proportional to the square c. both 'a' & 'b' d. neither 'a' nor 'b'

Answer 60

c. both 'a' & 'b'

Question 61

11. Which of the following is not a graphical method (but is an analytical method) for the calculation of theoretical number of stages in case of continuous binary distillation? a. Sorel-Lewis method. b. McCabe-Thiele's method. c. Ponchon-Savarit method. d. none of these.

Answer 61

a. Sorel-Lewis method.

Question 62

12. Saddle supports are used for supporting __________ vessels. a. horizontal cylinderical b. tall vertical c. thick walled vertical d. thick spherical

Answer 62

a. horizontal cylinderical

Question 63

13. The diameter of a propeller agitator used in agitation tank ranges from __________ percent of the tank diameter and its peripherial speed is normally 300 to 500 metres/minute. a. 5 to 10 b. 15 to 30 c. 40 to 50 d. 55 to 75

Answer 63

b. 15 to 30

Question 64

14. In packed towers provided with saddle packing, liquid redistributors are positioned at every __________ times column diameter or 6 metres whichever is less. a. 2-3 b. 5-8 c. 10-15 d. 20-25

Answer 64

b. 5-8

Question 65

15. Optimum reflux ratio in a continuous distillation column is determined by the a. maximum permissible vapour velocity. b. flooding limit of the column. c. total cost consideration (fixed cost of the column plus the cooling water & steam cost). d. none of these.

Answer 65

c. total cost consideration (fixed cost of the column plus the cooling water & steam cost).

Question 66

16. Cooling water fouling factors vary in the range of 0.001 to 0.003 a. (BTU/hr.ft2 . °F)^-1 b. (kcal/hr.m2 .°C)^-1 c. (W/m2.°K)^-1 d. (kcal/hr. m. °C)^-1

Answer 66

a. (BTU/hr.ft2 . °F)^-1

Question 67

17. Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter ) a. 0.2 D b. 0.5 D c. 0.66 D d. 0.80 D

Answer 67

a. 0.2 D

Question 68

18. The maximum liquid gradient over a tray must not exceed a. 0.5" -1.25". b. 2"-3.5". c. 5". d. half the tray spacing.

Answer 68

a. 0.5" -1.25".

Question 69

19. An underdesigned steam trap will a. waste steam. b. destroy itself of acceleration wear due to rapid recycling. c. back up condensate and cause water hammer in steam line. d. none of these.

Answer 69

c. back up condensate and cause water hammer in steam line.

Question 70

20. The slope of the feed line in distillation opeartion is given by (where, q = fraction of the feed stream that is liquid.) a. -q b. -q/(1-q) c. -q/(q-1) d. none of these

Answer 70

b. -q/(1-q)

Question 71

21. Speed of industrial paddle agitator ranges from __________ rpm. a. 1 to 5 b. 20 to 100 c. 500 to 750 d. 1000 to 2000

Answer 71

b. 20 to 100

Question 72

22. __________ strain is measured using a 'strain rosetter'. a. Volumetric b. Shear c. Linear d. none of these

Answer 72

c. Linear

Question 73

23. Thin spherical shells subjected to internal pressure, develop __________ stresses. a. radial b. circumferential c. both (a) & (b) d. neither (a) nor (b)

Answer 73

a. radial

Question 74

24. With increase in the reflux ratio for a fixed production from a continuous binary distillation column, the __________ decreases. a. fixed charges initially b. running cost of cooling water for condenser c. vapour & liquid load both d. running cost of steam for reboiler

Answer 74

a. fixed charges initially

Question 75

25. The slope of operating line in the rectifying section of a distillation column is unity, if the reflux ratio is a. 0 b. ∞ c. 1 d. minimum

Answer 75

b. ∞

Question 76

26. Vertical vessels are not supported by a. brackets b. skirts c. columns d. saddles

Answer 76

d. saddles

Question 77

27. With increase in pressure drop (for a given particle size), the dust collection efficiency of a cyclone separator will a. increase b. decrease c. remain unaffected d. increase or decrease depending on the nature of the dust.

Answer 77

a. increase

Question 78

28. Spherical shaped pressure vessel is considered to be the most ideal, because it can a. withstand higher pressure for a given metallic shell thickness. b. be fabricated very easily. c. be designed without wind load considerations. d. be supported very easily.

Answer 78

a. withstand higher pressure for a given metallic shell thickness.

Question 79

29. An adequate clearance between the tray and the shell wall of a distillation column is provided to a. drain the liquid from the tray when the unit is not in operation. b. allow for thermal expansion and facilitate installation. c. avoid back-trapping. d. none of these.

Answer 79

b. allow for thermal expansion and facilitate installation.

Question 80

30. Overall tray efficiency of a distillation column is the ratio of the number of a. overall gas transfer units to the number of ideal trays required. b. ideal trays required to the number of real trays required. c. real trays required to the number of ideal trays required. d. none of these.

Answer 80

b. ideal trays required to the number of real trays required.

Question 81

31. Pick out the wrong statement about the design of a sieve plate column. a. An increased weir height improves the tray efficiency at the cost of high plate pressure drop; optimum wear height being 40-90 mm for column pressure above atmospheric and 6-12 mm for vacuum columns. b. For segmental downcomers, the chord length is 60-80% of the column diameter. An initial value of downcomer area of 12% is taken in the design. c. Width of the calming section provided at the inlet and outlet sides of the plate is 75 mm for column diameter below 1.5 metres and 100 mm for larger diameter columns. d. Minimum recommended downcomer residence time for the disengagement of entrained vapour is the same for both foaming and non-foaming liquids, which is about 20 seconds.

Answer 81

d. Minimum recommended downcomer residence time for the disengagement of entrained vapour is the same for both foaming and non-foaming liquids, which is about 20 seconds.

Question 82

32. Generally, no corrosion allowance in wall thickness of a part is required, if the thickness is more than __________ mm. a. 10 b. 20 c. 30 d. 5

Answer 82

c. 30

Question 83

33. Multiple blade paddle agitator is used for mixing high viscosity liquids/paste in which the paddle diameter is commonly 0.8 times the tank diameter. However, the width of the blade is in the range of __________ times the paddle diameter. a. 0.1 to 0.25 b. 0.3 to 0.5 c. 0.5 to 0.6 d. 0.65 to 0.80

Answer 83

a. 0.1 to 0.25

Question 84

34. In a __________ rivetted joint, the rivets in the various rows are opposite to each other. a. zig-zag b. chain c. diamond d. none of these

Answer 84

b. chain

Question 85

35. Pick out the wrong statement: a. The tensile strength of a brittle material is less than its compressive strength. b. The compressive strength of a ductile materia] is less than its tensile strength. c. In a thick cylindrical shell, the hoop stress is maximum at the inner radius. d. The value of crushing load is more than that of buckling load for long colmns.

Answer 85

d. The value of crushing load is more than that of buckling load for long colmns.

Question 86

36. Generally, elliptical dished heads a. are manufactured on 2:1 ratio of major to minor axis and is recommended to be used for pressure vessels operating above a pressure of 1.5 MN/m2 . b. resist half the pressure rating compared to hemi spherical head provided on the cylindrical shell of the same thickness and diameter. c. are approximately as strong as seamless cylindrical shell having the corresponding I.D and O.D. d. all (a), (b) and (c)

Answer 86

d. all (a), (b) and (c)

Question 87

37. Pick out the wrong statement pertaining to the comparative evaluation of performance of the packed tower and the plate tower. a. Plate tower is perferred, if interstage cooling is required to remove heats of reaction or solution. b. Plate tower is preferred over packed tower, if the operation involves liquids containing dispersed solids. c. The total weight of a dry plate tower is usually much more than that of a dry packed tower designed for the same duty. d. In operations involving large temperature changes. (e.g. distillation), plate towers are preferred over packed towers a

Answer 87

c. The total weight of a dry plate tower is usually much more than that of a dry packed tower designed for the same duty.

Question 88

38. The circumferential (hoop) stress in a thin walled cylinderical vessel under internal pressure is a. pd/2t b. pd/4t c. pd/t d. pd/3t

Answer 88

a. pd/2t

Question 89

39. Le/D for fully open gate valves would be a. much more than that for fully open globe valves. b. much less (say 2% than that for fully open globe valves). c. around 7. d. both (b) and (c).

Answer 89

d. both (b) and (c).

Question 90

40. LMTD correction factor is used in heat exchanger design for a. double pipe heat exchanger. b. multipass shell and tube heat exchanger. c. fouling fluids. d. counter flow of hot and cold fluids.

Answer 90

b. multipass shell and tube heat exchanger.

Question 91

41. Floating head heat exchangers are used for the a. heat transfer between corrosive fluids. b. cases where temperature difference between the shell and the tubes is more (>50°C). c. co-current heat transfer systems. d. counter-current heat transfer systems.

Answer 91

b. cases where temperature difference between the shell and the tubes is more (>50°C).

Question 92

42. The most common standard size of bubble caps used in industrial operation is a. 1" dia cap with 0.5" dia riser. b. 6" dia cap with 4" dia riser. c. 8" dia cap with 1" dia riser. d. 4" dia cap with 8" dia riser.

Answer 92

b. 6" dia cap with 4" dia riser.

Question 93

43. Compensation against openings in process vessels for giving inlet and outlet connections, for providing sight glasses and manholes etc. is provided for strength and rigidity. The most efficient type of compensation is of __________ type. a. nozzle or rim b. flared out c. fluid in d. ring plate

Answer 93

a. nozzle or rim

Question 94

44. In case of a continuous distillation column, increase in reflux ratio may result in the a. lower fixed charges for the column. b. greater cost for the reboiler heat supply. c. greater cost for the condenser coolant. d. all (a), (b) and (c).

Answer 94

d. all (a), (b) and (c).

Question 95

45. In a distillation column, the minimum residence time for liquid in the downspout is about __________ seconds. a. 1 b. 8 c. 80 d. 180

Answer 95

b. 8

Question 96

46. Thickness of the frame of a plate and frame filter as compared to that of plates is a. less b. same c. more d. either (a) or (b)

Answer 96

c. more

Question 97

47. Which of the following factors affect the pressure drop in a co-current gas liquid absorption packed tower ? a. Size, shape, orientation and surface of the packing particles. b. Density and viscosity of fluids. c. Fluid flow rates. d. All (a), (b) and (c).

Answer 97

d. All (a), (b) and (c).

Question 98

48. The thickness of heat transfer plates used in the plate type heat exchanger ranges from __________ mm, pressed in a single piece provided with grooves & corrugations. a. 0.3 to 0.8 b. 1.25 to 3.125 c. 3.5 to 7.0 d. 8-12

Answer 98

b. 1.25 to 3.125

Question 99

49. Rivets are generally specified by the a. head diameter b. shank diameter c. overall length d. none of these

Answer 99

b. shank diameter

Question 100

50. Length to diameter ratio of most rotary driers is in the range of a. 1 to 2 b. 4 to 10 c. 10 to 20 d. 20 to 30

Answer 100

b. 4 to 10

Question 101

SECTION 3 1. Tube wall thickness depends on the cor-rosiveness of the fluids and their operating pressure & temperature and is specified by Birmingham wire gauge (B.W.G)-a number which varies from 8 to 18 with the numbers 14 and 16 being more commonly used. Outside diameter of tubes varies from about 15 to 50 mm; however a tube of less than __________ mm outside diameter is generally not recommended for fouling fluids.. a. 16 b. 19 c. 28 d. 38

Answer 101

b. 19

Question 102

2. Angled baffles are preferred in the agitation tank to control the swirling action; if the viscosity of the liquid to be mixed is about 200 poise. However, the baffle may be completely eliminated for mixing liquids having viscoisty above __________ poise.. a. 300 b. 600 c. 1000 d. 1500

Answer 102

b. 600

Question 103

3. Ratio of tube length to shell diameter for a shell and tube heat exchanger is a. 8 : 1 to 12 : 1 for both liquid-liquid and gas-gas heat exchangers. b. 4 : 1 to 8 : 1 for liquid-liquid exchanger. c. < 4 : 1 for gas-gas exchangers. d. both(b) & (c).

Answer 103

d. both(b) & (c).

Question 104

4. The dust collection efficiency of a cyclone separator a. decreases with increase in gas flow rate. b. is inversely proportional to the mass of the dust particle. c. is directly proportional to the radius of the dust particle path. d. none of these.

Answer 104

d. none of these.

Question 105

5. In a shell and tube heat exchanger, the overall heat transfer co-efficient is proportional to the tube side (volumetric flow rate)0.8. 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 105

b. 1

Question 106

6. Which of the following types of reactors is the safest from operation point of view ? a. A vapor phase reactor. b. Pot type reactor. c. A liquid phase reactor. d. A liquid phase catalytic reactor.

Answer 106

a. A vapor phase reactor.

Question 107

7. In a bag filter, the pressure drop increases directly as the a. density of the gas, but is independent of the viscosity of the gas. b. density of the gas and inversely as viscosity of the gas. c. viscosity of the gas and inversely as density of the gas. d. none of these.

Answer 107

b. density of the gas and inversely as viscosity of the gas.

Question 108

8. The LMTD correction factor (FT) is applied in __________ heat exchangers. a. cocurrent b. double pipe c. all multipass d. all (involving liquid/liquid heat transfer)

Answer 108

c. all multipass

Question 109

9. Movement of pipeline caused by thermal expansion is taken care by providing a. expansion joint. b. changes in its direction. c. change in the shape of pipeline. d. all (a), (b) and (c).

Answer 109

d. all (a), (b) and (c).

Question 110

10. For a cylindrical shell, (subject to the thickness of uppermost course being more than the minimum for diaofthe tank in question), the thickness of the courses of shell a. decreases upwards. b. increases upwards. c. remains same throughout. d. may decrease or increase upwards depending upon whether vacuum or positive pressure would be maintained inside the shell.

Answer 110

a. decreases upwards.

Question 112

12. The design stress, which is more than the damaging stress, is the least unit stress that will render a member unfit for service before the end of its normal life. The design stress factor or factor of safety indicates the margin between design stress and the __________ stress. a. working b. damaging c. allowable d. none of these

Answer 112

b. damaging

Question 113

13. Hole diameter of the seive trays in the distillation column ranges from __________ mm. a. l to 3 b. 4 to 8 c. 3 to 12.5 d. 12.5 to 18.5

Answer 113

c. 3 to 12.5

Question 114

14. Factor of safety (i.e., overdesign factor) in heat transfer equipments is about __________ percent more than the actual/theoretical design factor. a. 5-10 b. 15-20 c. 30-35 d. 35-40

Answer 114

b. 15-20

Question 116

16. In actual operation of distillation column, the vapour is not distributed uniformly among the bubble caps, primarily because of the a. liquid gradient on the tray. b. lower skirt clearance. c. lower static submergence. d. small downcomer liquid seal.

Answer 116

a. liquid gradient on the tray.

Question 117

17. The minimum shell thickness for tank ≤ 15 metres diameter is limited to __________ mm, for reasons of elastic stability. a. 2 b. 5 c. 10 d. 15

Answer 117

b. 5

Question 118

18. If 'D' is the inside diameter of the shell of a shell and tube heat exchanger, then the baffle spacing is usually in the range of a. D/2 or minimum 2" to 5D. b. D/5 or minimum 2" to 5D. c. D/5 or minimum 2" to D. d. none of these.

Answer 118

b. D/5 or minimum 2" to 5D.

Question 119

19. Brass valves are usually made for pipe sizes __________ inches. a. ≤1 b. ≤2 c. >2.5 d. >3.5

Answer 119

b. ≤2

Question 120

20. At the following point for a given packing and set of fluids, the pressure drop per metre of packed height, with variation in fluid rates and operating pressure a. increases b. decreases c. remains same d. may increase or decrease depending upon the solubility of the gas in the liquid

Answer 120

c. remains same

Question 121

21. In a shell and tube heat exchanger, triangular pitch arrangement as compared to square pitch arrangement a. results in higher shell side pressure drop. b. can accomodate less number of tubes for a given shell diameter. c. facilitates easier shell side cleaning; hence is more suitable for handling high dirt factor shell side fluid. d. creates relatively lower turbulence on the shell side resulting in lower shell side heat transfer co-efficient.

Answer 121

a. results in higher shell side pressure drop.

Question 122

22. Pick out the wrong statement about routing of fluids in a shell and tube heat exchanger. a. The corrosive and fouling fluid should be preferably routed through the tubes. b. The viscous fluid should be routed through the shell side. c. Lower flow rate fluid should be routed through the shell side. d. Higher pressure fluid stream should be routed through the shell side.

Answer 122

d. Higher pressure fluid stream should be routed through the shell side.

Question 123

23. The necessary wall thickness for a metallic storage vessel is a function of the a. ultimate tensile strength (or yield point) of the material and operating temperature. b. operating pressure and welding/joint efficiency. c. diameter of the vessel. d. all (a); (b) and (c).

Answer 123

d. all (a); (b) and (c).

Question 124

24. In a multiple effect evaporator system having 'n' 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 124

b. (1/n)th

Question 125

25. Pick out the wrong statement a. In a flanged and standard dished head, the crown radius is ≤ shell outside diameter. b. In a flanged and shallow dished head, the crown radius is > shell outside diameter. c. Flat head covers are most suitable for larger vessels operating at very high pressure. d. Flanged only head is a type of flat head in which gradual change in the shape at the centre results in reduced local stresses.

Answer 125

c. Flat head covers are most suitable for larger vessels operating at very high pressure.

Question 126

26. Pick out the wrong statement pertaining to the design of a horizontal tube evaporator. a. It is unsuitable for concentrating those liquids, which form a scale or deposit salt. b. It is suitable for process, in which the final product is a liquor instead of solid. c. Its usual dimensions are: tube dia = 2-3 cms; evaporator body dia = 1-4 metres and evaporator height = 2.5-4 metres. d. Liquor flows inside the tube, while the steam is outside submerging the tube.

Answer 126

d. Liquor flows inside the tube, while the steam is outside submerging the tube.

Question 127

27. Weep holes provided in the plates of a distillation column a. facilitate draining out liquid from a tray when the unit is not in operation. b. are normally located near the overflow weir so that any delivery of liquid during operation follows approximately the same path as the overflow fluid. c. must be large enough (usually 1/4" to 5/8" dia) to prevent plugging but should not deliver excessive amount of fluid during operation. d. all (a), (b) and (c).

Answer 127

d. all (a), (b) and (c).

Question 128

28. Steam is preferred to be used as a heating medium in heat exchangers, because of its a. low cost. b. high latent heat. c. non-corrosive condensate. d. high film co-efficient.

Answer 128

b. high latent heat.

Question 129

29. __________ shapedroof is the most commonly used roof for cylinderical storage tanks. a. Conical b. Flat c. Dome d. Umbrella

Answer 129

a. Conical

Question 130

30. Pick out the wrong statement pertaining to 'Horton sphere' used for the storage of liquid ammonia. a. Diameter of Horton sphere is normally 6 to 25 metres and it is supported by 6 to 12 nos. tubular or rolled section column. b. Thickness of spherical shell is half that of the cylinderical vessel under same operating pressure condition. Besides, the ratio of surface area to volume is less for sphere than any other shape ; hence insulation required is less. c. Horton sphere is used for the storage of gases and volatile liquid at a moderate pressure of 1 to 10 kg/cm2 . d. Horton sphere is used for the storage of liquid at sub-zero temperature at very high pressure upto 200 kg/cm2 .

Answer 130

d. Horton sphere is used for the storage of liquid at sub-zero temperature at very high pressure upto 200 kg/cm2 .

Question 131

31. Value of Peclet number = ∞, is the representative of a. laminar flow. b. complete back mixing, c. plug flow. d. eddy diffusivity = 0.

Answer 131

c. plug flow.

Question 132

32. Le/D for a Tee (used as elbow, entering branch) would be a. less than that for Tee (used as elbow, entering run). b. more than that for Tee (used as elbow, entering run). c. around 90. d. both (b) and (c).

Answer 132

d. both (b) and (c).

Question 133

33. In most of the shell and tube heat exchangers, the tube pitch is generally __________ the tube diameter. a. less than b. 1.25-1.50 times c. 2.5 times d. one-fourth of

Answer 133

b. 1.25-1.50 times

Question 134

34. In a distillation column, bubble caps are located on trays with a pitch of __________ times the outside diameter of the caps. a. 1.3 to 2 b. 1.6 to 2 c. 2.5 d. 1.5 to 3

Answer 134

a. 1.3 to 2

Question 135

35. 1.2 to 3.8 cms is the value of the a. downcomer liquid seal in case of a balanced tray design. b. static submergence in case of a bubble cap tray for column operating under pressure (≥ 1 atm.). c. skirt clearance for bubble caps. d. all (a), (b) and (c).

Answer 135

d. all (a), (b) and (c).

Question 136

36. Accidents in chemical plants are mostly due to a. inadequate equipment design. b. faulty operating procedures. c. improper layout of the equipments. d. failure of equipments.

Answer 136

b. faulty operating procedures.

Question 137

37. For identical operating conditions, the pressure drop over __________ tray is the highest out of the following. a. sieve b. valve c. counterflow d. bubble cap

Answer 137

d. bubble cap

Question 138

38. A perforated plate has holes of diameter dn arranged in a pitch ph. Each hole has a tube of I.D. dt passing through it. The ligament efficiency is given by a. (ph - dh)/ph b. (ph - dh . dt/2)/ph c. (ph - dt)/ph d. (ph - dh)/dh

Answer 138

c. (ph - dt)/ph

Question 139

39.__________ is the determining factor for the number of bubble caps to be used per tray. a. Permissible slot velocity b. Tray diameter c. Liquid load d. Vapor load

Answer 139

a. Permissible slot velocity

Question 140

40. Pick out the wrong statement about distillation operation a. Distillation under vacuum is a substitute for steam distillation. b. In differential (simple) distillation, the vapour is removed as soon as it is formed without appreciable condensation. c. In flash (equilibrium) distillation, a definite fraction of liquid is vaporised in such a way that the evolved vapour & residual liquids are in equilibrium with each other. d. Flash distillation, differential distillation & steam distillation are all continuous distillation processes.

Answer 140

d. Flash distillation, differential distillation & steam distillation are all continuous distillation processes.

Question 141

41. Low pressure steam (with saturation temperature between 105 to 120°C) is usually used in the vacuum evaporators, which normally employ a vacuum of about __________ mm Hg (referred to a 760 mm mercury barometer). a. 250 b. 450 c. 650 d. 750

Answer 141

c. 650

Question 142

42.Which of the following is the best tube material from thermal conductivity point of view alone? a. Aluminium b. Stainless steel c. Copper d. Carbon steel

Answer 142

c. Copper

Question 143

43. Normal screwed fittings are used for pipes upto a diameter of __________ inches. a. 1.5 b. 3 c. 5 d. 7

Answer 143

b. 3

Question 144

44. In a shell and tube heat exchanger, the clearance of the tube is generally a. not less than one-fourth of the tube diameter or 3/16". b. more than the tube diameter. c. equal to the tube diameter. d. more in case of triangular pitch as compared to the square pitch tube layout.

Answer 144

a. not less than one-fourth of the tube diameter or 3/16".

Question 145

45. Diameter of the seive tray column is determined by the a. lower limit of vapour velocity. b. upper limit of the vapour velocity. c. hole diameter of the seive tray. d. height of the plate spacing.

Answer 145

b. upper limit of the vapour velocity.

Question 146

46. For a given fluid, as the pipe diameter increases, the pumping cost a. decreases. b. increases. c. remains unaffected. d. may increase or decreaes depending upon whether the fluid is Newtonian or non-Newtonion.

Answer 146

a. decreases.

Question 147

47. Maximum acceptable total liquid gradient over a tray is about __________ mm. a. 5.5 b. 12.5 c. 30.5 d. 45.5

Answer 147

b. 12.5

Question 148

48.In case of a 'thin' pressure vessel, the ratio of its diameter to wall thickness is a. < 10 b. > 10 c. > 20 d. 30

Answer 148

a. < 10 b. > 10 c. > 20 d. 30

Question 149

49. High pressure fluid in a shell and tube heat exchanger should preferably be routed through the a. tubes to avoid the expansion of high pressure shell construction. b. shell side for smaller total pressure drop. c. shell side, if the flow is counter-current and tube side if the flow is co-current. d. shell side for large overall heat transfer co-efficient.

Answer 149

a. tubes to avoid the expansion of high pressure shell construction.

Question 150

50. Bubble cap tray is the most commonly used tray in large distillation column, because a. of its flexibility and nearly constant efficiency under varying conditions of operation. b. it incurs less pressure drop as compared to any other try designed for the same duty. c. it eliminates the foaming and entrain-ment tendency during operation. d. none of these.

Answer 150

a. of its flexibility and nearly constant efficiency under varying conditions of operation.

Question 151

SECTION 4 1. In common bubble cap distillation column design practice, riser area is approximately equal to (where, Aa = Annular passage area, and Sa = Slot area) a. Aa = Sa b. 1.2 Aa = 1.2 Sa c. Sa = 1.5 Aa d. Aa = 1.5 Sa

Answer 151

a. Aa = Sa

Question 152

2. 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 152

a. hG = 1.004G0.37

Question 153

3. In the agitators, the power required will be changed with the increase of diameter of agitator (D) as a. D^2 b. D^5 c. D d. D^9

Answer 153

b. D^5

Question 154

4. Apex angle of conical heads used in the bottom heads of chemical process equipments is usually a. 30° b. 45° c. 60° d. 75°

Answer 154

c. 60°

Question 156

6. A pressure vessel is said to be made of 'thick' shell, if the ratio of its diameter to wall thickness is a. 10 b. 10 c. 20 d. 20

Answer 156

a. 10

Question 157

7. Rate of filtrate delivery is inversely proportional to the a. filtering area & the pressure difference driving force. b. viscosity of filtrate. c. cake & filter medium resistance. d. both (a) and (b)

Answer 157

d. both (a) and (b)

Question 158

8. Tube side heat transfer co-efficient for turbulent flow of liquid through tubes is proportional to a. G^0.2 b. G^0.5 c. G^0.8 d. G^1.5

Answer 158

b. G^0.5

Question 159

9. Circumferential (hoop) stress in a thin cylindrical vessel under internal pressure is __________ the longitudinal stress. a. half b. equal to c. twice d. eight times

Answer 159

c. twice

Question 160

10. The dust collection efficiency of electrostatic precipitator increases with increase in the a. gas flow rate. b. electrode area. c. both (a) & (b). d. neither (a) nor (b).

Answer 160

b. electrode area.

Question 161

11. For storing hazardous chemicals in large storage tanks, the minimum safe distance between the two tanks should range between __________ times the tank diameter. a. 1 to 1.5 b. 2.5 to 3.5 c. 4 to 5 d. 6 to 8

Answer 161

a. 1 to 1.5

Question 162

12. Which of the following factors determine the amount of entrainment in a distillation column? a. Plate spacing. b. Depth of liquid above the bubble cap slots. c. Vapour velocity in the volume between the plates. d. All (a), (b) and (c).

Answer 162

d. All (a), (b) and (c).

Question 163

13. The absorption factor is defined as (where, S1 = slope of the equilibrium curve, S2 = slope of the operating line) a. S1/S2 b. S1.S2 c. S2/S1 d. 1/S1.S2

Answer 163

a. S1/S2

Question 164

14. In shell and tube heat exchangers, straight tie rods are used to a. hold baffle in space. b. fix the tubes in position. c. account for thermal strain. d. none of these.

Answer 164

a. hold baffle in space.

Question 166

16. In case of design of a shell and tube heat exchanger, a. minimum cleaning lane of 6.5 mm is provided, when tubes are on a square pitch. b. minimum tube sheet thickness (in which tubes are fixed) is equal to the O.D. of the tube upto 15 mm tube diameter; and for > 15 mm tube diameter, tube sheet thickness is smaller than tube diameter. c. O.D. of the tube is 6 to 40 mm while the tube lengths used are 0.5, 2.5, 3.0, 4.0, 5.0, 6 metres. d. all (a), (b) & (c).

Answer 166

d. all (a), (b) & (c).

Question 167

17. 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 167

a. σh = 2 σL

Question 168

18. Nominal size of a pipe is an indication of its __________ diameter. a. inner b. outer c. approximate d. none of these

Answer 168

c. approximate

Question 169

19. Excessive liquid gradient on a tray may result in the a. maldistribution of gas. b. back trapping. c. gas blowing beneath cap skit. d. all (a), (b) and (c).

Answer 169

d. all (a), (b) and (c).

Question 170

20. The ratio of tube length to shell diameter in case of liquid shell and tube heat exchanger ranges from a. 2 to 3 b. 3 to 5 c. 4 to 8 d. 6 to 12

Answer 170

c. 4 to 8

Question 172

22. What is the slope of the operating line in the stripping section of a distillation column ? a. 0 b. ∞ c. > 1 d. < 1

Answer 172

c. > 1

Question 173

23. __________ shaped roof is most commonly used for cylindrical tanks. a. Cone b. Dome c. Umbrella d. Flat

Answer 173

a. Cone

Question 174

24. In a thin cylindrical shell, the hoop stress is __________ stress. a. radial b. circumferential tensile c. compressive d. longitudinal

Answer 174

b. circumferential tensile

Question 175

25. Commercial packed scrubbers are normally designed for a pressure drop range of __________ mm water coloumn per metre of packed height. a. 4-8 b. 17-34 c. 52-68 d. 88-105

Answer 175

b. 17-34

Question 176

26. The retention time of material in a rotary dryer depends upon its a. rpm b. slope & length c. flights arrangement d. all (a), (b) and (c)

Answer 176

d. all (a), (b) and (c)

Question 177

27. In actual operation of a bubble cap distillation tower, the __________ at the bottom of the tower is more than that at the top of the tower. a. molal flow rate of vapour b. vapour molecular weight c. pressure and temperature d. all (a), (b) and (c)

Answer 177

d. all (a), (b) and (c)

Question 178

28. Rotary driers are most economically designed for the number of heat transfer units (HTU) from a. 0.01 to 1 b. 1.5 to 2.5 c. 5 to 10 d. 10 to 20

Answer 178

b. 1.5 to 2.5

Question 179

29. The difficulty of liquid distribution in packed towers is accentuated, when the ratio of tower diameter to packing diameter is a. < 30 b. < 7 c. 7 < 15 d. 20 < 50

Answer 179

b. < 7

Question 180

30. A forced circulation long tube vertical evaporator as compared to the natural circulation evaporator a. is economical in operation. b. employs high velocity, high heat transfer rate and less heating surface requirement. c. employs a centrifugal pump placed between external downtake from vapor drum and inlet to tube bundle. d. both (b) & (c).

Answer 180

d. both (b) & (c).

Question 181

31. An increase in the liquid resistance to interphase mass transfer and a resultant reduction in plate efficiency is caused by a. an increase in liquid viscosity. b. an increase in relatived volatility for rectification columns. c. decrease in gas solubility for absorbers. d. all (a), (b) and (c).

Answer 181

d. all (a), (b) and (c).

Question 182

32. In the design of a bag filter, the gas temperature is an important consideration, as it affects the a. gas density b. gas viscosity c. fibre selection d. all (a), (b) & (c)

Answer 182

d. all (a), (b) & (c)

Question 183

33. With increase in temperature drop (in a shell and tube heat exchanger), the LMTD correction factor, FT a. decreases very rapidly b. increases very rapidly c. remains constant d. increases linearly

Answer 183

a. decreases very rapidly

Question 184

34. The normal range of velocity of steam in pipes is __________ m/sec. a. 0.1-0.5 b. 1-5 c. 10-20 d. 80-100

Answer 184

d. 80-100

Question 185

35. __________ dished head is the strongest of all. a. Hemispherical b. Elliptical c. Torispherical d. none of these

Answer 185

a. Hemispherical

Question 186

36. Pick out the correct statement. a. It is preferred to use a vertical condenser for condensation of vapor from a distillation column without sub-cooling b. Draining of residual liquid on tray during shut down of distillation column is facilitated by weep holes. c. Random packing a packed tower offers the advantage of lower pressure drop and higher throughput of fluids as compared to regular/stacked packing. d. Risers are generally not connected to the plate in a distillation coloumn by bolts, rivets or welding.

Answer 186

d. Risers are generally not connected to the plate in a distillation coloumn by bolts, rivets or welding.

Question 187

37. "A claming section" before the liquid flows into the downcomer is privided to a. permit release of entrained vapour in the liquid. b. reduce the discharge fluctuation. c. ensure better vapour-liquid contact. d. cool the liquid before it flows down.

Answer 187

a. permit release of entrained vapour in the liquid.

Question 188

38. The units of Young's modulus of elasticity and __________ are the same. a. strain b. stress c. modular ratio d. none of these

Answer 188

b. stress

Question 189

39. In the design of a shell and tube heat exchanger, the corrosion allowance a. need not be provided for non-pressure parts like tie rods, spacers, baffles, supports etc. b. for carbon steel and cast iron pressure parts is 1.5 mm (except for tubes) and for severe conditions it is 3 mm. c. for internal cover and tube sheet is provided on both the sides. d. all (a), (b) & (c).

Answer 189

d. all (a), (b) & (c).

Question 190

40. Vertical condenser is advantageous to the horizontal condenser from operation point of view, when a. hydrostatic head is required for refluxing the condensate. b. only the function of condensation is to be carried out. c. sub cooling of condensate is desired. d. both the functions of condensation & sub cooling are carried out in a single unit.

Answer 190

d. both the functions of condensation & sub cooling are carried out in a single unit.

Question 191

41. Hazards associated with the relief valve leakage for extremely hazardous material storage can be taken care of by providing a. rupture diaphragm b. dikes c. surge chamber d. none of these

Answer 191

a. rupture diaphragm

Question 192

42. Minimum baffle spacing recommended in a shell and tube heat exchanger is equal to a. 5 cms b. 40% of the I.D. of the shell c. 25 cms d. I.D. of the shell

Answer 192

a. 5 cms

Question 193

43. __________ liquor is best handled in a long tube vertical evaporator. a. Foamy b. Scaling c. Viscous d. Salting

Answer 193

a. Foamy

Question 194

44. Theoretically calculated diameter of the stripping section of the continuous rectification column is __________ that of the enriching section. a. less than b. more than c. same as d. either more or less (depending upon relative volatility)

Answer 194

b. more than

Question 195

45. Hold up of material in a operating rotary drier is in the range of a. 0.05 to 0.15 b. 0.25 to 0.50 c. 0.5 to 0.8 d. 0.8 to 0.9

Answer 195

a. 0.05 to 0.15

Question 196

46. A binary liquid azeotropic mixture has boiling point higher than either of the components, when it shows __________ deviation from Raoult's Law. a. positive b. negative c. no d. none of these

Answer 196

b. negative

Question 197

47. The testing pressure of storage tanks and pressure vessels designed as per Indian standard codes should be about __________ times.the design pressure. a. 1.5 to 2 b. 3 to 4 c. 4 to 5 d. >5

Answer 197

a. 1.5 to 2

Question 198

48. Flanges are connected to pipes by a. screwing b. welding c. brazing d. all (a), (b) and (c)

Answer 198

d. all (a), (b) and (c)

Question 199

49. The ratio of down take area to cross-sectional area of the tube, for calendria type evaporator ranges from a. 0.5 to 1 b. 1 to 1.5 c. 1.5 to 2 d. 2 to 2.5

Answer 199

a. 0.5 to 1 b. 1 to 1.5 c. 1.5 to 2 d. 2 to 2.5

Question 200

50. Shortest distance between two tubes is a. called tube pitch. b. called tube clearance. c. more in case of triangular pitch as compared to square pitch of tube layout. d. none of these.

Answer 200

b. called tube clearance.

Question 201

SECTION 5 1. __________ tower is the most suitable gas-liquid contacting device involving highly corrosive fluids. a. Sieve plate b. Packed c. Bubble cap plate d. None of these

Answer 201

a. Sieve plate b. Packed c. Bubble cap plate d. None of these

Question 202

2. At equal mass velocities, the values of film co-efficients for gases as compared to that for liquids are generally. a. higher b. lower c. same d. unpredictable

Answer 202

b. lower

Question 203

3. The ratio of the largest load in a test to the original cross-sectional area of the test specimen is called the __________ stress. a. yield point b. breaking c. ultimate d. none of these

Answer 203

c. ultimate

Question 204

4. Baffle spacing is generally __________ the I.D. of the shell. a. more than b. not greater than c. not less than one fifth of d. both (b) and (c)

Answer 204

d. both (b) and (c)

Question 205

5. The wall thickness of thin cylindrical shell with hemispherical ends is __________ that of the spherical ends. a. equal to b. more than c. less than d. either (b) or (c); depends on maximum permissible internal pressure

Answer 205

b. more than

Question 206

6. A 'rupture disc' is provided in chemical equipments as an accessory meant for a. relieving excess pressure. b. creating turbulence. c. enhancing mixing rate. d. avoiding vortex formation.

Answer 206

a. relieving excess pressure.

Question 207

7. In a vertical short tube evaporator (Calendria type), the a. tube dia of 2.5-7.5 cms, tube length of 75-200 cms and cylinderical drum dia of 1-6 metres are normally used. b. area of central downtake is equal to 40 to 100% of total cross sectional area of the surrounding tube. c. liquor is inside the tube while the steam is outside the tube. d. all (a), (b) & (c).

Answer 207

d. all (a), (b) & (c).

Question 209

9. In a shell and tube heat exchanger, the shortest centre to centre distance between the adjacent tubes is a. called tube pitch. b. called tube clearance. c. always less than the diameter of the tube. d. none of these.

Answer 209

a. called tube pitch.

Question 210

10. Any shell opening greater than 5 cms for a storage tank must be reinforced for reason of a. preventing the local overstressing of the shell around the opening. b. reduction of discontinuity in shape at the junction. c. making the joint leak proof. d. none of these.

Answer 210

a. preventing the local overstressing of the shell around the opening.

Question 211

11. Minimum tube pitch recommended for shell and tube heat exchangers is about __________ times the outside diameter of the tube. a. 1.25 b. 1.75 c. 2.5 d. 3.5

Answer 211

a. 1.25

Question 212

12. Liquid redistribution should be done in a packed tower packed with raschig rings every 6 metres or __________ times the column diameter, whichever is lower. a. 2.5-3.0 b. 5-7.5 c. 10-12.5 d. 15-20

Answer 212

a. 2.5-3.0

Question 213

13. Slope of countercurrent flow rotary drier is in the range of __________ meter/metre. a. 0 to 0.08 b. 0 to 0.8 c. 0 to 1.5 d. 0 to 2.2

Answer 213

a. 0 to 0.08

Question 214

14. In case of saddle packing (e.g., berl and intralox saddles), the maximum size of the packing should not exceed __________ of the column diameter. a. l/5th b. l/15th c. l/30th d. l/50th

Answer 214

b. l/15th

Question 215

15. Seamless pipe is made a. from rolled strips formed into cylinders and seam-welded. b. by extrusion & casting into static and centrifugal molds. c. by forging a solid round, piercing it by simultaneously rotating & forcing it over a piercer point and further reducing it by rolling gas drawing. d. both (b) and (c).

Answer 215

d. both (b) and (c).

Question 216

16. The thermal stress in a metallic bar does not depend upon the a. changes in temperature. b. cross-sectional area. c. both (a) and (b). d. neither (a) nor (b).

Answer 216

b. cross-sectional area.

Question 217

17. The minimum baffle height should be a. equal to the impeller diameter. b. twice the impeller diameter. c. twice the tank diameter. d. 3/4 of the tank height.

Answer 217

b. twice the impeller diameter.

Question 219

19. To avoid the tearing off the plate of an edge, the margin (i.e., the minimum distance from the centre of the rivet hole to the nearest edge of the plate) should be equal to a. 0.5 d b. d c. 1.5 d d. 2.5 d

Answer 219

c. 1.5 d

Question 220

20. The normal range of velocity of water in pipes is __________ m/sec. a. 0.1-0.5 b. 1-2 c. 10-50 d. 15-30

Answer 220

b. 1-2

Question 221

21. Baffles are provided in a shell and tube heat exchanger to increase the turbulence and velocity of the shell side fluid. Which of the following shaped baffles does not fall in the category of transverse baffle ? a. Segmental baffle b. Flat plate extending across the wall c. Disk type baffle d. Helical type baffle

Answer 221

b. Flat plate extending across the wall

Question 222

22. A certain pressure vessel manufacturer avoids doing reinforcements calculations for openings by always providing a reinforcing pad extending upto double the diameter of the opening and of the same material and thickness as that of the shell wall. If area compensation is accepted as a code guideline, his approach leads to safe design a. only if the opening is on spherical vessel. b. only if the opening is on a vertical cylinderical vessel. c. only if the opening is on a horizontal cylinderical vessel. d. irrespective of the shape of the vessel.

Answer 222

d. irrespective of the shape of the vessel.

Question 223

23. In a __________ rivetted joint, the number of rivets decreases from the innermost row to the outermost row. a. chain b. diamond c. zig-zag d. none of these

Answer 223

b. diamond

Question 224

24. Large process vessels operating under extreme temperature and pressure conditions are normally clad/ lined with materials like stainless steel, aluminium, nickel & its alloys, copper & its alloys and titanium. The cladding thickness is generally about __________ percent of the total thickness. a. 1 to 5 b. 10 to 20 c. 30 to 40 d. 40 to 50

Answer 224

b. 10 to 20

Question 225

25. Heat transfer co-efficient for a horizontal condenser as compared to a vertical condenser operating under similar conditions is a. same b. less c. about 3 times d. about 0.33 times

Answer 225

c. about 3 times

Question 226

26. Pick out the wrong statement pertaining to the design of the distillation column. a. Generally, a skirt clerance of 0.5" to 1.5' is recommended to prevent plugging of the slots by residue build up. b. The purpose of the slot is to disperse the gas into the liquid in the form of small bubbles. c. If sufficient slot area is not provided, the gas may pass through the skirt clearance. d. none of these.

Answer 226

d. none of these.

Question 227

27. The longitudinal stress induced in a thin walled cylinderical vessel under internal pressure is a. pd/2t b. pd/4t c. pd/t d. pd/8t

Answer 227

b. pd/4t

Question 228

28. In distillation columns, bubble caps are held in place over trays by a. rivets b. a hold down bar c. bolts d. both (b) and (c)

Answer 228

d. both (b) and (c)

Question 229

29. The buckling tendency of compression members is always in the direction of the a. least radius of gyration. b. axis of the load. c. perpendicular to the axis of the load. d. none of these.

Answer 229

a. least radius of gyration.

Question 230

30. 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 230

c. 3.8

Question 231

31. The average velocity in the tubes of a 1-4 heat exchanger is __________ times that in 1-1 heat exchanger having the same size & number of tubes and operated at same liquid flow rate. a. 2 b. 1/2 c. 4 d. 1/4

Answer 231

c. 4

Question 233

33. When one of the fluids is highly corrosive and has fouling tendency, it should a. preferably flow inside the tube for its easier internal cleaning. b. perferably flow outside the tube. c. flow at a very slow velocity. d. flow outside the tube, when the flow is counter-current and inside the tube when the flow is co-current.

Answer 233

a. preferably flow inside the tube for its easier internal cleaning.

Question 235

35. A/an __________ is used for changing the direction of a pipeline. a. elbow b. union c. flange d. disc compensator

Answer 235

a. elbow

Question 236

36. Maximum plate efficiency is achieved in case of __________ flow. a. split b. cross c. cascade d. reverse

Answer 236

b. cross

Question 237

37. The LMTD correction factor (FT) is defined as the a. ratio of true temperature difference to the LMTD. b. ratio of LMTD to the true temperature difference. c. differenced of true temperature difference and the LMTD. d. geometric mean of the true temperature difference and the LMTD.

Answer 237

a. ratio of true temperature difference to the LMTD.

Question 238

38. 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. equal to b. half c. one fourth d. three fourth

Answer 238

c. one fourth

Question 239

39. The ratio for the rate of washing to the final rate of filtration in a washing type of plate and frame filter is a. 0.25 b. 0.50 c. 0.75 d. 1.25

Answer 239

a. 0.25

Question 240

40. Normally, the length to diameter ratio of rotary dryers varies form 4 to 10 and for its economic operation, the number of transfer units (NTU) for such dryers varies from a. 1.5-2.5 b. 3.5-5.5 c. 7.5-10.0 d. 10-15

Answer 240

a. 1.5-2.5

Question 241

41. Value of Peclet number = 0, is the representative of a. laminar flow. b. complete back mixing. c. plug flow. d. eddy diffusivity = 0.

Answer 241

b. complete back mixing.

Question 242

42. Poisson's ratio of a material is the ratio of unit lateral strain to the unit axial elongation within its elastic limit. The value of Poisson's ratio for structural and pressure vessel steel may be taken as a. 0.01 b. 0.3 c. 0.75 d. 0.95

Answer 242

b. 0.3

Question 243

43. Removable connection of tubes to tube sheet is called a. ferrule b. socket c. nipple d. saddle

Answer 243

a. ferrule

Question 245

45. Typical static submergence for bubble cap plate column operating at atmospheric pressure may be around a. 2.5" b. 0.5" c. 5" d. 50% of the plate spacing

Answer 245

b. 0.5"

Question 246

46. In the allocated cap area, bubble caps are generally arranged on equilateral triangular pitch. Number of caps fixed on a plate is with a a. clearance of 25-75 mm. b. cap pitch of 1.3-2 times the cap diameter. c. either 'a' or 'b'. d. neither 'a' nor 'b'.

Answer 246

c. either 'a' or 'b'.

Question 247

47. The length of straight rectangular weir used on cross-flow trays is generally __________ the column diameter. a. 0.6-0.8 times b. equal to c. twice d. 2 ft irrespective of (for column > 3 ft diameter)

Answer 247

a. 0.6-0.8 times

Question 248

48. Le/D for couplings and unions would be a. 60 b. 200 c. 350 d. negligible

Answer 248

d. negligible

Question 249

49. What is the slope of the operating line in the rectifying section of a distillation coloumn ? a. 0 b. ∞ c. > 1 d. <1

Answer 249

d. <1

Question 250

50. Stage efficiency for packed tower varies with the a. type & size of packing. b. fluid rates and fluid properties. c. operating pressure and column diameter. d. all (a), (b) and (c).

Answer 250

d. all (a), (b) and (c).

Question 251

SECTION 6 1. The minimum plate spacing in most of the pertroleum refinery distillation columns (of dia > 3 ft) is normally __________ inches. a. 6 b. 12 c. 18 d. 34

Answer 251

c. 18

Question 252

2. Joint efficiency (J) for a seamless pipe is a. 1 b. 0.85 c. 1.2 d. < 0.5

Answer 252

a. 1

Question 253

3. For a given design of bubble cap, the number of bubble caps to be used per tray is set by the a. allowable gas velocity through the slots. b. plate spacing. c. diameter of the column. d. all (a), (b) and (c).

Answer 253

a. allowable gas velocity through the slots.

Question 254

4. The shell side pressure drop in a shell and tube heat exchanger is maximum for __________ baffle. a. disk and ring b. segmental c. orifice d. independent of the type of

Answer 254

c. orifice

Question 255

5. The function of manholes provided in the shell of a distillation column is to a. keep a check on the liquid gradient over the plate by direct visual observation. b. give access to the individual trays for cleaning, maintenance and installation. c. guard against foaming & entrainment by dumping antifoaming agent through it. d. all (a), (b) and (c).

Answer 255

b. give access to the individual trays for cleaning, maintenance and installation.

Question 256

6. Back-trapping in a distillation column results due to a. low gas velocity. b. high gas velocity. c. excessive liquid gradient over the tray. d. low reflux ratio.

Answer 256

c. excessive liquid gradient over the tray.

Question 257

7. 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. 1.0 d. (0.8)^0.5

Answer 257

a. 0.8

Question 258

8. Diameter of bubble caps used in high pressure columns is __________ as compared to that used in identical vacuum columns. a. less b. more c. same d. either (a) or (b); no generalisation can be made

Answer 258

b. more

Question 259

9. The ideal size of round bubble caps to be used in industrial distillation column having a diameter of 3-6 metres is __________ cms. a. 5 b. 15 c. 7.5 d. 50

Answer 259

b. 15

Question 260

10. Lap joints are preferred for plates having thickness __________ mm. a. < 12.5 b. > 3 c. > 5 d. 5-10

Answer 260

b. > 3

Question 261

11. In a distillation column, minimum clearance to be maintained betweeen the overflow weir and the last row of the bubble caps is __________ cms. a. 2.5 b. 7.5 c. 15 d. 20

Answer 261

b. 7.5

Question 262

12. Which of the following lengths of heat exchanger tubes are normally not used in practice ? a. 2.5 metres b. 6 metres c. 10 metres d. 0.5 metre

Answer 262

c. 10 metres

Question 263

13. A pipe is generally made of circular cross-section, because a circular cross section has the a. higher structural strength. b. lowest surface area requirement for a given volume. c. both (a) & (b). d. none of these.

Answer 263

c. both (a) & (b).

Question 264

14. In case of a shell and tube heat exchanger, the effect of L/D on inside film heat transfer co-efficient (hi) vanishes after a Reynold number of a. 1000 b. 3000 c. 5000 d. 10000

Answer 264

d. 10000

Question 265

15. Equivalent diameter for heat transfer calculation for a duct of square cross section having each side as 'd' will be a. d b. sqrt d c. sqrt 2πd d. sqrt 2d

Answer 265

a. d

Question 266

16. A cylindrical storage tank can have a self supported conical roof, a. if its diameter is less than 15-20metres. b. if its diameter is more than 50 meters. c. if the thickness of the roof is more than that of the cylindrical shell. d. irrespective of its diameter.

Answer 266

a. if its diameter is less than 15-20metres.

Question 267

17. For high pressure process equipments/vessels, the connected nozzle should be a. welded b. screwed c. flanged d. brazed

Answer 267

c. flanged

Question 268

18. Smoker's equation for the calculation of number of equilibrium stages in a continuous binary distillation column is used, when the a. relative volatility is close to one (e.g., separation of close boiling isomers). b. feed is not at its bubble point. c. number of equilibrium stages in only stripping section is to be calculated. d. number of equilibrium stages required is likely to be very small.

Answer 268

a. relative volatility is close to one (e.g., separation of close boiling isomers).

Question 269

19. Column support for the roof of cylindrical storage tank must be provided for a. small diameter tanks. b. large diameter tanks. c. small diameter tall tanks. d. all tanks irrespective of their heights and diameters.

Answer 269

b. large diameter tanks.

Question 270

20. For a cylinderical internally pressurised vessel, which of the following closure types would withstand highest pressure, if each closure is of the same material and thickness ? a. hemispherical b. ellipsoidal (2 : 1) c. conical d. flat plate

Answer 270

b. ellipsoidal (2 : 1)

Question 271

21. In inclined long tube vertical evaporators, the tubes are inclined at an angle of a. 15° b. 90° c. 45° d. 60°

Answer 271

c. 45°

Question 272

22. In a continuous distillation column, the optimum reflux ratio ranges from __________ times the minimum reflux ratio. a. 1.1 to 1.5 b. 1.6 to 2 c. 2.2 to 2.6 d. 2.7 to 3

Answer 272

a. 1.1 to 1.5

Question 273

23. The wall thickness for a large high pressure pipeline is determined by the consideration of the a. axial tensile stress in the pipe. b. forces exerted by static and dynamic action at bends. c. circumferential pipewall tension. d. temperature stresses.

Answer 273

c. circumferential pipewall tension.

Question 274

24. In the case of a shell and tube heat exchanger, the logarithmic mean temperature difference a. is always less than arithmetic average value. b. is always more than arithmetic mean value and the geometric mean value. c. is always less than arithmetic mean value, but more than geometric mean value. d. may be either more or less than geometric mean and arithmetic mean value depending upon whether the flow of stream is co-current or counter-current.

Answer 274

a. is always less than arithmetic average value.

Question 275

25. Skirt support is the most suitable for supporting __________ vessels. a. small horizontal b. large horizontal c. tall vertical d. thick walled

Answer 275

c. tall vertical

Question 276

26. Baffles may be eliminated for a. low viscosity liquids (< 200 poise). b. high viscosity liquids (> 600 poise). c. large diameter tanks. d. none of these.

Answer 276

b. high viscosity liquids (> 600 poise).

Question 277

27. Generally, as the length of the liquid path on a tray is increased beyond 5 ft, the overall column efficiency a. increases b. decreases c. remains same d. may increase or decrease depending upon the plate spacing

Answer 277

a. increases

Question 278

28. In packed absorption tower, onset of flooding usually occurs at a pressure drop of about __________ mm of water column per metre height of packing. a. 25-50 b. 50-75 c. 200-250 d. 750-1000

Answer 278

b. 50-75

Question 279

29. For pipe flows, head is proportional to __________ at constant capacity (where D = pipe diameter ). a. 1/D b. 1/D^2 c. 1/D^5 d. D^2

Answer 279

b. 1/D^2

Question 281

31. The minimum tray spacing in distillation column of diameter less than 3 ft is normally __________ inches. a. 6 b. 18 c. 24 d. 35

Answer 281

a. 6 b. 18 c. 24 d. 35

Question 282

32. Oxygen carrying pipelines in chemical industries are coloured with __________ colour. a. yellow b. black c. blue d. red

Answer 282

c. blue

Question 283

33. Normally, the ratio of the total riser area to the tower cross sectional area (for bubble cap towers of diameter more than 3 ft) is around a. 0.4-0.6 b. 0.35-0.75 c. 0.1-0.2 d. 0.55-0.85

Answer 283

c. 0.1-0.2

Question 284

34. Pick out the wrong statement about the design of seive plate column and the bubble cap column. a. The downcomer design and the residence time in the downcomer is almost same for seive plate and bubble cap columns. b. Weir length for a bubble cap plate is the same as that for the seive plate. c. Weir height for a bubble cap plate column is the same as that for a seive plate column. d. Weir height in case of a bubble cap plate ranges from 50 to 150 mm and is higher than the seive plate.

Answer 284

c. Weir height for a bubble cap plate column is the same as that for a seive plate column.

Question 285

35. Maximum size of the raschig rings used in a packed tower is about __________ of the coloumn diameter. a. 1/10th b. 1/20th c. 1/30th d. 1/50th

Answer 285

c. 1/30th

Question 287

37. The type of stress developed in a metallic bar on subjecting it to a change in temperature without allowing it to be deformed is __________ stress. a. shear b. tensile c. compressive d. thermal

Answer 287

d. thermal

Question 288

38. The safe distance of habitation from a hazardous chemical plant (TLV of its product < 1000 ppm) should be about __________ kms. a. 1 b. 5 c. 15 d. 25

Answer 288

d. 25

Question 289

39. Pick out the wrong statement pertaining to a shell and tube heat exchanger. a. The minimum value of baffle spacing is 50 mm. b. The maximum value of baffle spacing is equal to the I.D. of the shell. c. The maximum unsupported tube span is generally about 75 times tube diameter, but is reduced to about 60 times for aluminium, copper & alloys of these. d. Disk and doughnut baffle is the most commonly used baffle.

Answer 289

d. Disk and doughnut baffle is the most commonly used baffle.

Question 290

40. Corrosion allowance in the design of pressure vessel/chemical equipment is not necessary, if a. plain carbon steel and cast iron parts are used. b. wall thickness is > 30 mm. c. material of construction is high alloy steel. d. both(b) & (c).

Answer 290

d. both(b) & (c).

Question 291

41. Maximum allowable vapour velocity in a bubble cap tower is determined by the a. entrainment considerations. b. vapour density. c. diameter of the column. d. none of these.

Answer 291

a. entrainment considerations.

Question 292

42. Normally, the plate thickness of the bottoms and roofs of vertically cylindrical storage vessels as compared to that of the cylindrical shell is a. more b. less c. same d. more or less depending upon the pressure & temperature inside the vessel and the nature of the fluid contained therein.

Answer 292

b. less

Question 293

43. The practical representative values of HETP for a number of commercial operations lies within a range of __________ metre. a. 0.1-0.2 b. 0.2-0.5 c. 0.4-0.9 d. 1.2-1.5

Answer 293

c. 0.4-0.9

Question 294

44. Of the pressure vessels, with same thickness but different diameters, which one withstands higher pressure ? a. Larger dia vessel. b. Smaller dia vessel. c. Larger dia long vessel. d. Strength of the vessel is same irrespective of the diameter.

Answer 294

b. Smaller dia vessel.

Question 295

45. Reflux ratio variation in a distillation column is between a. zero and infinity b. zero and one c. minimum and infinity d. none of these

Answer 295

c. minimum and infinity

Question 297

47. In condenser, the cooling water is passed in the tube side in a pass arrangement, because a. it reduces heat transfer area. b. more thinner tubes can be used. c. pressure drop is reduced. d. it makes condenser compact.

Answer 297

a. it reduces heat transfer area.

Question 298

48. In packed towers provided with pall rings liquid redistributors are positioned at heights of every 6 metres or 5-10 times the column diameter, whichever is less. Maximum size of the pall rings should not exceed __________ of the column diameter. a. 1/10-1/15th b. 1/5-1/10th c. 1/20-1/30th d. 1/2 to 1/4th

Answer 298

a. 1/10-1/15th

Question 299

49. Height of the flights in the rotary drier is in the range of a. 0.08 to 0.12 d b. 0.02 to 0.05 d c. 0.2 to 0.5 d d. 0.5 to 0.6 d

Answer 299

a. 0.08 to 0.12 d

Question 300

50. Vapor velocity in a distillation column for non-foaming mixture is in the range of __________ times the flooding velocity. a. 0.1 to 0.3 b. 0.6 to 0.7 c. 0.85 to 0.95 d. 1.5 to 2

Answer 300

b. 0.6 to 0.7

Question 301

SECTION 7 1. Cylindrical storage tanks used for the storage of volatile liquids (e.g., naphtha) have __________ roofs. a. conical b. flat c. floating d. fixed

Answer 301

a. conical b. flat c. floating d. fixed

Question 302

2. Larger depth of liquid on the trays of a distillation column a. leads to high tray efficiency. b. results in higher pressure drop per tray. c. both (a) & (b). d. neither (a) or (b).

Answer 302

c. both (a) & (b).

Question 303

3. Pick out the wrong statement. a. Plate efficiency increases with increase in superficial vapour velocity till entrainment limit. b. Increase in depth of the liquid about the slots increases the plate efficiency, particularly if the liquid depth is < 1". c. Too small a plate spacing can cause a low efficiency, if the vapour velocity is greater than the allowable value. d. none of these.

Answer 303

d. none of these.

Question 304

4. Pick out the wrong statement. a. In practical operation, distillation towers having diameter 3-6 metres equipped with bubble cap (round) size of 15 cms are used. b. Height of packing in a packed tower is about 3 times the column diameter for raschig rings and about 5 to 10 times the column diameter for saddle packing. c. In a seive tray, the minimum hole diameter is equal to the tray thickness. d. In a stainless steel seive tray, the minimum hole diameter is equal to 10 times the plate thickness.

Answer 304

d. In a stainless steel seive tray, the minimum hole diameter is equal to 10 times the plate thickness.

Question 305

5. In the downcomer of a distillation column, the minimum recommended residence time is about __________ seconds. a. 2.5 b. 5 c. 12.5 d. 17.5

Answer 305

b. 5

Question 306

6. For identical situation, condensing film coefficient in case of a horizontal condenser is almost __________ the value expected in case of vertical condenser. a. half b. twice c. thrice d. five times

Answer 306

c. thrice

Question 307

7. Diameter of rivet hole (d, mm) and the plate thickness (t, mm) are related by Unwin's formula as a. d = 1.1 t b. d = 1.6 sqrt t c. d = 1.5 t d. 3 sqrt t

Answer 307

b. d = 1.6 sqrt t

Question 308

8. A binary liquid azeotropic mixture has boiling point lower than either of the components, when it shows __________ deviation from Raoult's Law. a. positive b. negative c. no d. none of these

Answer 308

a. positive

Question 309

9. In which of the following evaporators, steam is fed inside the tube while the liquor is outside the tube? a. Long tube vertical evaporator b. Short tube vertical evaporator c. Horizontal tube evaporator d. None of these

Answer 309

c. Horizontal tube evaporator

Question 310

10. A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of a. 2 b. 2^0.8 c. 2^0.2 d. none of these

Answer 310

b. 2^0.8

Question 311

11. In a multipass shell and tube heat exchanger, the baffles on shell side is primarily provided for a. reducing scale deposition. b. increasing pressure drop. c. fixing the tubes. d. creating turbulence.

Answer 311

d. creating turbulence.

Question 312

12. For turbine agitator, the impeller diameter is about a. 0.3 to 0.5 d b. 0.1 to 0.2 d c. 0.65 to 0.85 d d. 0.95 d

Answer 312

a. 0.3 to 0.5 d

Question 314

14. If a single tube pass heat exchanger is converted to two passes; for the same flow rate, the pressure drop per unit length in tube side will __________ times. a. increase by 1.8 b. decrease by 2^2 c. increase by 2^1.6 d. none of these

Answer 314

c. increase by 2^1.6

Question 316

16. Pick out the wrong statement pertaining to the design of a long tube vertical evaporator. a. Tube dia is 3-6 cms, while tube length in 3-6 metres. b. Steam is fed to the shell, whereas the liquor is filled inside the tube. c. Liquor level is maintained at l/3rd to 1/2 of the height of the tube. d. none of these.

Answer 316

d. none of these.

Question 317

17. Which of the following is the most common type of baffle used in industrial shell and tube heat exchanger ? a. 75% cut segmental baffle. b. 25% cut segmental baffle. c. Orifice baffle. d. Disk and doughnut baffle.

Answer 317

b. 25% cut segmental baffle.

Question 318

18. What is the minimum recommended ligament for square pitch arrangement in case of heat exchangers ? a. 6.5 cms b. 6.5 mm c. Equal to tube I.D d. Equal to tube O.D

Answer 318

b. 6.5 mm

Question 319

19. Pick out the correct statement a. Centre to centre distance between two consecutives rivets in a row is called the pitch. b. A rivetted joint made in overlapping plates is called butt joint. c. Hole size drilled in rivetted plates is less than the actual size of the rivet. d. none of these.

Answer 319

a. Centre to centre distance between two consecutives rivets in a row is called the pitch.

Question 320

20. Safety valves are provided in chemical equipments to guard against excessive a. temperature b. pressure/pressure fluctuation c. turbulence d. noise

Answer 320

b. pressure/pressure fluctuation

Question 321

21. The equivalent diameter for pressure drop is __________ that for heat transfer. a. smaller than b. greater than c. equal to d. not related with

Answer 321

d. not related with

Question 322

22. Most of the storage vessels/tanks are made cylindrical, because of the fact that a cylinder a. has greater structural strength. b. is easy to fabricate. c. both (a) and (b). d. neither (a) nor (b).

Answer 322

c. both (a) and (b)

Question 323

23. The distance between the top of the slots and the liquid surface when the static liquid is just ready to flow over the overflow weir is called a. downcomer liquid seal b. static submergence c. skirt clearance d. none of these

Answer 323

b. static submergence

Question 324

24. Liquid gradient over the tray results due to the a. resistance offered to flow of liquids by caps & risers and the flow of gas. b. low gas velocity. c. large plate spacing. d. large reflux ratio.

Answer 324

a. resistance offered to flow of liquids by caps & risers and the flow of gas.

Question 325

25. 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. To increase the residence time of shell side fluid. b. To provide support to the tube bundle. c. To reduce the induced vibration in the tubes. d. To increase the tube side heat transfer co-efficient by inducing turbulence.

Answer 325

d. To increase the tube side heat transfer co-efficient by inducing turbulence.

Question 326

26. A high vapour velocity is required for high plate efficiency in a seive plate coloumn. The satisfactory value of operating vapor velocity for design purpose in seive plate column is about __________ percent of the flooding velocity. a. 45 b. 60 c. 80 d. 95

Answer 326

c. 80

Question 327

27. The approximate liquid depth in an agitation tank is equal to (where, d = tank diameter) a. 0.5 d b. 0.75 d c. d d. 2 d

Answer 327

c. d

Question 328

28. Baffle width is normally taken as __________ times the tank diameter. a. 0.1-0.12 b. 0.4-0.5 c. 0.45-0.6 d. 0.2-0.45

Answer 328

a. 0.1-0.12

Question 329

29. 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 329

d. 10 mm

Question 330

30. Which of the following packing materials provides for maximum mass transfer ? a. Lessig rings. b. Raschig rings. c. Cross-partition rings. d. All give the same value.

Answer 330

c. Cross-partition rings.

Question 331

31. __________ of water makes it a widely used coolant in heat exchangers. a. Low corrosiveness b. Low dirt factor c. High specific heat d. Low viscosity

Answer 331

c. High specific heat

Question 332

32. The equivalent diameter for fluid flow through a channel of constant non circular cross section of area 'A' is given by (where, P = perimeter of the channel in contact with the fluid) a. 4 A/P b. A/P c. 4 P/A d. Sqrt A

Answer 332

a. 4 A/P

Question 333

33. Fouling factor must be included in the calculation of over all design heat transfer coefficient, when the liquid a. containing suspended solids flows at low velocity. b. containing suspended solids flows at high velocity. c. is highly viscous. d. is of high specific gravity.

Answer 333

a. containing suspended solids flows at low velocity.

Question 334

34. Lug support is meant for supporting __________ vessels. a. large horizontal cylindrical b. tall but empty c. small d. thick walled tall

Answer 334

c. small

Question 335

35. Overall mass transfer co-efficient in case of absorption of __________ in water is based on the gas film co-efficient only, as the mass transfer process is gas film (phase) controlling. a. CO2 b. SO2 c. NH3 d. none of these

Answer 335

c. NH3

Question 336

36. Which tube arrangement in a heat exchanger would facilitate highest heat transfer rate? a. Triangular pitch. b. Square pitch. c. Diagonal square pitch. d. Heat transfer rate is independent of tube arrangement.

Answer 336

a. Triangular pitch.

Question 337

37. In case of 1.5" heat exchanger tubes, the inside flow area __________ with decrease in BWG. a. increases b. decreases c. remains same d. none of these

Answer 337

b. decreases

Question 338

38. Cylindrical pressure vessels in horizontal condition is generally supported on a __________ support. a. lug b. skirt c. saddle d. guy wire

Answer 338

c. saddle

Question 339

39. Pressure drop per tray in the atmospheric distillation column is about __________ psi. a. 0.01 - 0.5 b. 0.07 - 0.12 c. 0.5 - 1.0 d. 1 - 3

Answer 339

b. 0.07 - 0.12

Question 340

40. Welded joint efficiency in the design of chemical process equipment is taken as a. 0.55 b. 0.75 c. 0.85 d. 0.95

Answer 340

c. 0.85

Question 341

41. The thickness of segmental baffles (25 -35% cut truncated plates usually) is generally __________ the tube wall thickness. a. equal to b. twice c. four times d. half

Answer 341

b. twice

Question 342

42. The safe height (h) to diameter (d) ratio (i.e., h/d) 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 342

a. 1

Question 343

43. For given number of passes, pitch & tube diameter, the maximum number of tubes that can be accommodated in a shell of tripled inside diameter will be __________ times. a. about 9 b. considerably more than 9 c. considerably less than 9 d. about 3

Answer 343

b. considerably more than 9

Question 344

44. The ratio of linear stress to linear strain is termed as the a. modulus of elasticity b. modulus of rigidity c. bulk modulus d. none of these

Answer 344

a. modulus of elasticity

Question 345

45. __________ head is the most economical for cylindrical vessels designed for operating at high pressure (> 15 atm.). a. Hemispherical b. Dished c. Ellipsoidal d. Conical

Answer 345

c. Ellipsoidal

Question 346

46. Bubble cap plate column is a. a finite stage contactor. b. used only for distillation, not for absorption. c. a differential stage contactor. d. a continuous contactor.

Answer 346

a. a finite stage contactor.

Question 347

47. In seive plate column, holes are drilled or punched in sizes ranging from 2.5 to 12 mm (5 mm being widely used). The hole pitch is normally __________ times the hole diameter to give the required hole area. a. 0.5 to 1.5 b. 2.5 to 4.0 c. 5 to 10 d. 10 to 15

Answer 347

b. 2.5 to 4.0

Question 348

48. Pick out the wrong statement. a. Rivetting provides a permanent fastening method. b. The joint made by overlapping of one plate over the other, and then rivetting the two plates together with two rows of rivets is called 'double rivetted butt joint'. c. Shank diameter of the rivets should be less than the size of the hole drilled in the plate for rivetting. d. The efficiency of a rivetted joint is the ratio of the strength of the rivetted joint to the strength of the solid plate.

Answer 348

b. The joint made by overlapping of one plate over the other, and then rivetting the two plates together with two rows of rivets is called 'double rivetted butt joint'.

Question 349

49. The force due to wind load acting on a tall vessel depends upon its a. shape. b. outside diameter. c. height. d. all (a), (b) & (c).

Answer 349

d. all (a), (b) & (c).

Question 350

50. Bubble cap diameter used for the distillation column having diameter ranging from 1.5 to 4.5 metres is about __________ mm. a. 10 b. 50 c. 100 d. 150

Answer 350

c. 100

Question 351

SECTION 8 1. Power required for agitation depends upon the a. height & properties of the liquid. b. agitator type & speed of agitation. c. size of agitator & the tank. d. all (a), (b) and (c).

Answer 351

d. all (a), (b) and (c).

Question 352

2. Tube height in a calendria type evaporator is normally less than __________ metres. a. 1 b. 2 c. 3.5 d. 5.5

Answer 352

b. 2

Question 353

3. Pick out the wrong statement. a. Lug supports are less expensive than other type of supports. b. A pipe is differentiated from a tube by the fact that a pipe has a greater wall thickness compared to the tube. c. A reducer is used to change the direction of a pipe in a straight run. d. The method of fixing tubes to a tube sheet by expanding is called 'tube rolling'.

Answer 353

c. A reducer is used to change the direction of a pipe in a straight run.

Question 354

4. For a 25 mm hole drilled in plates to be rivetted, the shank diameter of the rivet should be __________ mm. a. 25 b. 23 c. 26 d. 27

Answer 354

b. 23

Question 356

6. Optimum economic pipe diameter for fluid flow is determined by the a. viscosity of the fluid. b. density of the fluid. c. total cost considerations (pumping cost plus fixed cost of the pipe). d. none of these.

Answer 356

c. total cost considerations (pumping cost plus fixed cost of the pipe).

Question 357

7. Pressure differential maintained across a continuous rotary vacuum filter is in the range of __________ mm Hg column. a. 50 to 100 b. 100 to 150 c. 250 to 500 d. 600 to 700

Answer 357

c. 250 to 500

Question 358

8. Vertical storage vessels are never supported by __________ support. a. bracket b. saddle c. skirt d. lug

Answer 358

b. saddle

Question 359

9. In a double pipe (concentric) heat exchanger, the hydraulic radius for heat transfer (for a fluid flowing through the annulus) would be a. same as that for fluid flow. b. less than that for fluid flow. c. more than that for fluid flow. d. D2 - D1 (D1 and D2 are I.D. of inner and outer pipes respectively).

Answer 359

c. more than that for fluid flow.

Question 360

10. 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 E = modulus of elasticity) a. E b. σ c. σ/E d. E/σ

Answer 360

c. σ/E

Question 361

11. In a pressure vessel containing multiple openings of various dimensions at different parts, stress concentration at the edges of the opening is maximum which becomes negligibly small beyond the area covered by __________ times the hole diameter. a. two b. five c. ten d. twenty

Answer 361

a. two

Question 362

12. What is the slope of the feed line, if the feed to a distillation column is a saturated liquid ? a. 0 b. ∞ c. > 1 d. < 1

Answer 362

b. ∞

Question 363

13. Filtration rate is affected by the a. pressure drop across the cake & filter medium. b. cake & filter medium resistance. c. area of filtering surface & the viscosity of filtrate. d. all (a), (b) and (c).

Answer 363

d. all (a), (b) and (c).

Question 364

14. Liquid gradient over a tray can be minimised by a. providing a higher skirt clearance or a higher weir. b. decreasing the number of rows of caps through which the liquid flows or by decreasing the velocity of liquid flow past the caps or by reducing the distance along the tray through which the liquid must flow. c. using split flow, radial flow or cascade flow for column diameter large than 4 ft. d. all (a), (b) and (c).

Answer 364

d. all (a), (b) and (c).

Question 365

15. In a shell and tube heat exchanger for a given heat transfer surface area, smaller diameter tubes are favoured as compared to larger diameter ones ; because the smaller diameter tubes a. are easier to clean. b. are less prone to fouling. c. can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less. d. none of these.

Answer 365

c. can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less.

Question 366

16. Le/D 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 366

a. 25 and 60

Question 367

17. __________ heat exchanger is also known as 'hair pin type' exchanger, a. Double pipe b. Finned c. Plate type d. Regenerative

Answer 367

a. Double pipe

Question 368

18. What is the value of 'q' for saturated vapor feed to a distillation column ?(where q = fraction of the feed stream that is liquid.) a. 0 b. 1 c. <0 d. >1

Answer 368

a. 0

Question 369

19. In hydrostatic testing of welded pipe (for leakage, strength etc.) the ratio of minimum hydrostatic test pressure to internal design pressure is around a. 0.5 b. 1.5 c. 2.5 d. 3.5

Answer 369

b. 1.5

Question 370

20. Frame thickness in the plate and frame filter press is normally in the range of __________ inches. a. 0.25 to 4 b. 0.25 to 8 c. 1 to 5 d. 1 to 12

Answer 370

b. 0.25 to 8

Question 371

21. Cylinderical shell thickness of rotary drier is generally __________ mm. a. 2-3 b. 18-22 c. 6-8 d. 12-15

Answer 371

c. 6-8

Question 372

22. The ratio of lateral strain to linear strain is termed as the a. Poisson's ratio b. bulk modulus c. modulus of elasticity d. shear modulus

Answer 372

a. Poisson's ratio

Question 373

23. The distance between the centre of a rivet hole to the nearest edge of the plate is called a. pitch b. margin c. back pitch d. none of these

Answer 373

b. margin

Question 374

24. Mc Cable Thiele method used for finding theoretical stages in a distillation column assumes that the a. sensible heat differences are small, because the temperature changes from tray to tray is small. b. Trouton's rule is applicable. c. liquid/vapor loading across the column remains constant. d. all (a), (b) and (c).

Answer 374

d. all (a), (b) and (c).

Question 375

25. A minimum clearance of about __________ mm is maintained between the distillation column wall and the bubble cap. a. 19 b. 38 c. 76 d. 95

Answer 375

b. 38

Question 376

26. Pick out the wrong statement. a. If sufficient residence time (around 8 seconds) is not proivided to the downcoming liquid in the downcomer, it may entrain some vapour. b. The liquid head in the downcomer should not be greater than one half the plate spacing to avoid flooding. c. The dischare end of the downcomer must project far enough into the tray liquid so that no gas bubbles can enter the open end and by pass the bubble caps. d. none of these.

Answer 376

d. none of these.

Question 377

27. Pick out the wrong statement pertaining to shell and tube heat exchanger. a. Clearance between shell & baffles and between tube & baffles should be minimum to avoid by-passing of the fluid, but it should be enough to permit the removal of tube bundle. b. Baffles are supported independently of the tubes by tie rods and positioned by spacers. c. Tie rods are fixed at one end in the tube sheet by making blind holes and the minimum number of tie rods is 4 with at least 10 mm diameter. d. Bracket supports are used for horizontal shell, while saddle support is used for vertical shell.

Answer 377

d. Bracket supports are used for horizontal shell, while saddle support is used for vertical shell.

Question 378

28. Wind load consideration in the design of a support can be neglected, when the vessel is a. tall (say 30 metres), but is full of liquid. b. tall but empty. c. short (< 2 m) and housed indoor. d. none of these.

Answer 378

c. short (< 2 m) and housed indoor.

Question 380

30. The ratio of volumes of the mixed reactor to the plug flow reactor (for identical feed composition, flow rate, conversion, and for all positive reaction orders) is always a. 1 b. < 1 c. >1 d. equal to the order of reaction

Answer 380

c. >1

Question 381

31. Steam economy is defined as the amount of evaporation per unit amount of steam used, while the capacity 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 381

d. both 'b' & 'c'.

Question 382

32. Le/D for a Tee (used as elbow, entering run) would be around a. 5 b. 60 c. 200 d. 350

Answer 382

b. 60

Question 383

33. Log mean temperature difference in case of multi-pass shell and tube heat exchanger is always a. less than arithmetic mean value. b. more than arithmetic mean value. c. more than geometric mean value. d. both(b) & (c).

Answer 383

a. less than arithmetic mean value.

Question 385

35. Tubes are fixed to the tube sheet (a thick circular metallic plate) by the method of tube rolling and brazing (non-removable) or ferrule connection (removable). Thickness of the tube, sheet is normally __________ the outside diameter of the tube but in no case it should be less than 22 mm (7/8"). a. half b. three fourth c. equal to d. 1.5 times

Answer 385

c. equal to

Question 386

36. A shell may by termed as thin if its thickness to diameter ratio is less than 0.1. The factor which can be neglected in the calculation of membrane stresses is a. bending b. deformation c. shear d. elongation

Answer 386

a. bending

Question 387

37. Scale up problem in design based on the similarity concept takes into account __________ similarity. a. geometrical b. kinematic c. dynamic d. all (a), (b) and (c)

Answer 387

d. all (a), (b) and (c)

Question 388

38. __________ closure is the weakest enclosure for cylindrical vessels. a. Hemispherical b. Torispherical c. Conical or flat plate d. Elliptical

Answer 388

c. Conical or flat plate

Question 389

39. Which of the following efficiencies can be greater than 100% ? a. Overall plate efficiency. b. Murphree plate efficiency. c. Point efficiency. d. None of these.

Answer 389

b. Murphree plate efficiency.