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Indiabix > Process Equipment and Plant Design > Flashcards

Process Equipment and Plant Design Flashcards

1
Q

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

A

sea green

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2
Q

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

A

Rimmed Steel

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3
Q

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

A

shear modulus

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4
Q

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.

A

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

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5
Q

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

A

45

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6
Q

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

A

300

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7
Q

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).

A

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

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8
Q

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.

A

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

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9
Q

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.

A

increases

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10
Q

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

A

2.5 to 5

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11
Q

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

A

5-11

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12
Q

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

A

elastic limit

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13
Q

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 adjacent tube holes.
c. shortest centre to centre distance between adjacent tubes.
d. none of these.

A

shortest centre to centre distance between adjacent tubes.

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14
Q

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.

A

Reflux is not a saturated liquid.

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15
Q

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. η = 24.6 Δp/μ
c. η = 1.66 - 0.25 log μ
d. η = 0.25 log μ - 1.67

A

η = 17 - 61.1 log μ

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16
Q

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

A

10

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17
Q

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

A

8

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18
Q

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

A

(1.2)^5/3

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19
Q

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.

A

At the inner surface.

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20
Q

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

A

0.80

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21
Q

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

A

none of these

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22
Q

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).

A

permits the use of MORE tubes in a given shell diameter.

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23
Q

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

A

thick-walled vertical

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24
Q

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

A

none of these

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25
Q

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

A

inside diameter

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26
Q

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

A

7500

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27
Q

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

A

20

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28
Q
  1. In chemical process equipments, the conical bottom heads used, usually has an apex angle of
    a. 20°
    b. 40°
    c. 60°
    d. 80°
A

60°

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29
Q

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

A

75

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30
Q

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

A

less

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31
Q

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.

A

ultimate stress to working stress.

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32
Q

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

A

20-40

33
Q

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

A

Cross flow

34
Q

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

A

1

35
Q

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.

A

facilitate handling of large flow rate of liquid.

36
Q

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

A

50-150

37
Q

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

A

Ellipsoidal

38
Q

For laminar flow (NRe < 2100) in steel pipe, the optimum inside pipe
diameter is given by
a. Di, opt = 3 Q^0.36 ρ^0.18
b. Di, opt = 3.9 Q^0.45 . ρ^0.23
c. Di, opt = 7.6 Q^0.36 . ρ^0.9
d. Di, opt = 3 Q^0.36 . ρ^1.86 μ^0.08

A

Di, opt = 3 Q^0.36 ρ^0.18
(yung 3 tas walang μ)

39
Q

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.

A

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

40
Q

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

A

less

41
Q

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.

A

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

42
Q

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.

A

none of these

43
Q

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

A

0.1 to 2

44
Q

Pressure drop (Δp) and the superficial gas mass velocity (G) in case of
packed absorption tower operating in the preloading range are related as
a. Δp = G
b. Δp = G^0.5
c. Δp = G^2
d. Δp = 1/G^0.6

A

Δp = G^2

45
Q

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.

A

dished bottom vessel has very high power consumption.

46
Q

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.

A

very large diameter pipes.

47
Q

Pick out the wrong statement.
a. Safety valves are provided in heat exchangers for removal of non-condensables.
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.

A

Safety valves are provided in heat exchangers for removal of non-condensables.

48
Q

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

A

decreases

49
Q

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.

A

central dished section and corner torus section.

50
Q

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.

A

Allowable vapour velocity.

51
Q

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.

A

SMALLER reactor should come first.

52
Q

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.

A

Sorel-Lewis method

53
Q

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

A

horizontal cylinderical

54
Q

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

A

15 to 30

55
Q

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

A

5-8

56
Q

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.

A

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

57
Q

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

A

(BTU/hr.ft2. °F)^-1

58
Q

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

A

0.2 D

59
Q

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.

A

0.5” -1.25”

60
Q

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.

A

back up condensate and cause water hammer in steam line.

61
Q

The slope of the feed line in distillation operation 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

A

-q/(1-q)

62
Q

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

A

20 to 100

63
Q

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

A

Linear

64
Q

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

A

radial

65
Q

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

A

fixed charges initially

66
Q

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

A

∞

67
Q

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

A

saddles

68
Q

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.

A

increase

69
Q

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.

A

withstand higher pressure for a given metallic shell thickness.

70
Q

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.

A

allow for thermal expansion and facilitate installation.

71
Q

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.

A

ideal trays required to the number of real trays required.

72
Q

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.

A

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.

73
Q

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

A

30

74
Q

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

A

0.1 to 0.25

75
Q

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

A

chain

76
Q

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 material 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 columns.

A

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

77
Q

Pick out the wrong statement pertaining to the comparative evaluation of
performance of the packed tower and the plate tower.
a. Plate tower is preferred, 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 as the packing may be crushed due to large temperature changes.

A

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

78
Q

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

A

pd/2t

79
Q
A

Indiabix (2 decks)

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