INDIABIX-PROCESS EQUIPMENT AND PLANT DESIGN Flashcards by Vince Rafael Candelaria

Fresh water carrying pipelines in chemical industries are coloured with __________ color.
sea green
brown
yellow
red

sea green

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Which of the following material is seldom used for pressure vessel construction ?
Rimmed still
Mild steel
Killed steel
Semi-killed steel

Rimmed still

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The ratio of shear stress to shear strain is called
bulk modulus
shear modulus
modulus of rigidity
modulus of elasticity

shear modulus

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25 per cent cut segmental baffle means that the baffle
height is 75% of the I.D. of the shell.
height is 25% of the I.D. of the shell.
spacing is 75% of its height.
width is 25% of its height.

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

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

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Le/D for fully open globe value may be around
10
25
75
300

300

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

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

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Pick out the wrong statement pertaining to the use of valve tray, seive tray and bubble cap trays in continuous distillation column.
»>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.
»>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.
»>Maintenance cost for valve and seive trays are comparatively more than bubble cap tray due to their relatively complicated construction features.
»>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.

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

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

increases

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

2.5 to 5

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The stress developed in a material without any permanent set is called the
ultimate stress
yield stress
elastic limit
breaking stress

elastic limit

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

shortest centre to centre distance between adjacent tubes.

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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 ?
»Sensible heat changes for vapour & liquid are negligibly small.
»Reflux is not a saturated liquid.
»Molar latent heat of the two components are equal.
»Heat of mixing of normal liquid is assumed to be zero.

Reflux is not a saturated liquid.

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

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

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

both (a) & (b)

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

At the inner surface.

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

0.80

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

none of these

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

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

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

thick walled vertical

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

none of these

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Two iron pipes of the same nominal diameter but different schedule numbers will have the same ___.
inside diameter
outside diameter
wall thickness
none of these

inside diameter

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Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m2.°C.
1250
2500
7500
15000

7500

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

both (b) and (c).

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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. 5 20 35 55

In chemical process equipments, the conical bottom heads used, usually has an apex angle of 20° 40° 60° 80°

60°

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. 25 50 75 150

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 __. more same less twice

less

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

ultimate stress to working stress.

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. 1-5 20-40 100-150 1000-1500

20-40

__________ tray arrangement is recommended for distillation column having diameter upto 4 ft. Radial flow Cross flow Split flow Cascade

Cross flow

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

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

facilitate handling of large flow rate of liquid.

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. Flat plate Hemispherical Torispherical Ellipsoidal

Ellipsoidal

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

Di, opt = 3 Q^0.36 ρ^0.18

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

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

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

less

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

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

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. >>The pressure drop due to the caps & slots and the static submergence should be as high as practicable for reasonable operation. >>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. >>The dimensionless ratio of liquid gradient to pressure drop head caused by the bubble cap assembly should be less than 0.4. >>none of these.

none of these.

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

0.1 to 2

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

prevention of fluid leakage around moving parts.

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

Δp = G^2

Pick out the wrong statement. >>>In an agitated vertical cylinderical reaction vessel, the ratio of liquid depth to tank diameter (i.e. the filling ratio) recommended for most purposes is 1. >>>filling ratio for dispersing gas in a liquid is 2 for sufficiently long contact period. >>>flat bottom and conical bottom vessels have low agitation efficiency for agitation of heavy solids in liquids. >>>dished bottom vessel has very high power consumption.

dished bottom vessel has very high power consumption.

Needle valves are generally not used for ____ very large diameter pipes. high pressure throttling service. very accurate flow control. smaller sizes of pipe.

very large diameter pipes.

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 ______ flow rates of each fluid. type and size of packing. concentration of each fluid. all a, b & c.

all a, b & c.

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

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

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 ___ >>>central dished section and corner torus section. >>>corner torus section and central dished section. >>>central dished section and straight flange section. >>>straight flange section and corner torus section.

central dished section and corner torus section.

Which of the following is used to set the diameter of the distillation column ? >>Number of theoretical plates. >>Static submergence. >>Allowable vapor velocity. >>Length of straight rectangular weir on cross-flow tray.

Allowable vapor velocity.

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 >>>is more accurate in finding the number of equilibrium stages. >>>accounts for the enthalpy changes in the process. >>>facilitates direct calculation of heat load on reboiler & condenser from, the diagram used in this method. >>>all 'a', 'b' & 'c'.

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

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 >>>equal sized reactors are the best. >>>smaller reactor should come first. >>>larger reactor should come first. >>>none of these.

smaller reactor should come first.

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'

c.) both 'a' & 'b'

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? Sorel-Lewis method. McCabe-Thiele's method. Ponchon-Savarit method. none of these.

Sorel-Lewis method

Saddle supports are used for supporting __________ vessels. horizontal cylindrical tall vertical thick walled vertical thick spherical

horizontal cylindrical

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. 5 to 10 15 to 30 40 to 50 55 to 75

15 to 30

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.

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

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

0.2 D

__________ strain is measured using a 'strain rosetter'. Volumetric Shear Linear none of these

Linear

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

radial

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

fixed charges initially

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

∞

Vertical vessels are not supported by brackets skirts columns saddles

saddles

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

increase

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.

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.

b) allow for thermal expansion and facilitate installation.

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.

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

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

chain

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

multipass shell and tube heat exchanger.

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.

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

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. nozzle or rim flared out fluid in ring plate

nozzle or rim

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

Rivets are generally specified by the head diameter shank diameter overall length none of these

shank diameter

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. 16 19 28 38

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 ∞ 1 20.8 2

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

A vapor phase reactor.

The LMTD correction factor (FT) is applied in __________ heat exchangers. 1-1 cocurrent double pipe all multipass all (involving liquid/liquid heat transfer)

all multipass

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.

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

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. working damaging allowable none of these

damaging

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

15-20

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

liquid gradient on the tray.

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 accommodate 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.

a) results in higher shell side pressure drop.

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.

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

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.

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

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.

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

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

high latent heat.

__________ shapedroof is the most commonly used roof for cylinderical storage tanks. Conical Flat Dome Umbrella

Conical

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 .

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

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

plug flow.

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

1.25-1.50 times

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

faulty operating procedures.

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

bubble cap

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

Permissible slot velocity

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.

D) Flash distillation, differential distillation & steam distillation are all continuous distillation processes.

Which of the following is the best tube material from thermal conductivity point of view alone? Aluminium Stainless steel Copper Carbon steel

Copper

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

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

upper limit of the vapour velocity.

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.

A) tubes to avoid the expansion of high pressure shell construction.

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.

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

In the agitators, the power required will be changed with the increase of diameter of agitator (D) as D^2 D^5 D D^9

D^5

Tube side heat transfer co-efficient for turbulent flow of liquid through tubes is proportional to G^0.2 G^0.5 G^0.8 G^1.5

G^0.8

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

twice

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

electrode area.

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

hold baffle in space.

In a cylinderical vessel subjected to internal pressure, the longitudinal stress σL and the circumferential stress, σn are related by σh = 2 σL σh = σL σh = σL/2 no relation exists

σh = 2 σL

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

approximate

__________ shaped roof is most commonly used for cylindrical tanks. Cone Dome Umbrella Flat

Cone

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

circumferential tensile

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

1.5 to 2.5

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

decreases very rapidly

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

80-100

__________ dished head is the strongest of all. Hemispherical Elliptical Torispherical none of these

Hemispherical

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.

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

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

permit release of entrained vapour in the liquid.

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

stress

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

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

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

rupture diaphragm

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

Foamy

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

negative

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.

B) called tube clearance.

__________ tower is the most suitable gas-liquid contacting device involving highly corrosive fluids. Sieve plate Packed Bubble cap plate None of these

Packed

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

ultimate

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

relieving excess pressure.

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.

A) called tube pitch.

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.

A) preventing the local overstressing of the shell around the opening.

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? Segmental baffle Flat plate extending across the wall Disk type baffle Helical type baffle

Flat plate extending across the wall

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.

D) irrespective of the shape of the vessel.

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

diamond

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

pd/4t

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.

A) least radius of gyration.

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.

A) preferably flow inside the tube for its easier internal cleaning.

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

elbow

Maximum plate efficiency is achieved in case of __________ flow. split cross cascade reverse

cross

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

A) ratio of true temperature difference to the LMTD.

Value of Peclet number = 0, is the representative of laminar flow. complete back mixing. plug flow. eddy diffusivity = 0.

complete back mixing.

Removable connection of tubes to tube sheet is called ferrule socket nipple saddle

ferrule

What is the slope of the operating line in the rectifying section of a distillation coloumn ? 0 ∞ > 1 <1

Joint efficiency (J) for a seamless pipe is 1 0.85 1.2 < 0.5

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).

A) allowable gas velocity through the slots.

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

orifice

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).

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

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

excessive liquid gradient over the tray.

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.

A) if its diameter is less than 15-20metres.

For high pressure process equipments/vessels, the connected nozzle should be welded screwed flanged brazed

flanged

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.

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

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.

B) large diameter tanks.

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 ? hemispherical ellipsoidal (2 : 1) conical flat plate

ellipsoidal (2 : 1)

In inclined long tube vertical evaporators, the tubes are inclined at an angle of 15° 90° 45° 60°

45°

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.

C) circumferential pipewall tension

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.

A) is always less than arithmetic average value.

Skirt support is the most suitable for supporting __________ vessels. small horizontal large horizontal tall vertical thick walled

tall vertical

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

high viscosity liquids (> 600 poise).

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

increases

Oxygen carrying pipelines in chemical industries are coloured with __________ colour. yellow black blue red

blue

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.

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

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

1/30th

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. shear tensile compressive thermal

thermal

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

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.

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

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

entrainment considerations.

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

0.4-0.9

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.

b) Smaller dia vessel.

Reflux ratio variation in a distillation column is between zero and infinity zero and one minimum and infinity none of these

minimum and infinity

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.

a) it reduces heat transfer area.

Cylindrical storage tanks used for the storage of volatile liquids (e.g., naphtha) have __________ roofs. conical flat floating fixed

floating

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.

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

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

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

thrice

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

positive

In which of the following evaporators, steam is fed inside the tube while the liquor is outside the tube? Long tube vertical evaporator Short tube vertical evaporator Horizontal tube evaporator None of these

Horizontal tube evaporator

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

creating turbulence.

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

25% cut segmental baffle.

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.

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

Safety valves are provided in chemical equipments to guard against excessive temperature pressure/pressure fluctuation turbulence noise

pressure/pressure fluctuation

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 downcomer liquid seal static submergence skirt clearance none of these

static submergence

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.

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

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.

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

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. 45 60 80 95

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

Cross-partition rings.

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

High specific heat

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.

a) containing suspended solids flows at low velocity.

Lug support is meant for supporting __________ vessels. large horizontal cylindrical tall but empty small thick walled tall

small

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. CO2 SO2 NH3 none of these

NH3

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.

a) Triangular pitch.

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

saddle

Welded joint efficiency in the design of chemical process equipment is taken as 0.55 0.75 0.85 0.95

0.85

The ratio of linear stress to linear strain is termed as the modulus of elasticity modulus of rigidity bulk modulus none of these

modulus of elasticity

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

Ellipsoidal

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.

a) a finite stage contactor.

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.

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'.

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

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'.

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

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.

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

Vertical storage vessels are never supported by __________ support. bracket saddle skirt lug

saddle

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) E σ σ/E E/σ

σ/E

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

∞

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.

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

__________ heat exchanger is also known as 'hair pin type' exchanger, Double pipe Finned Plate type Regenerative

Double pipe

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

The ratio of lateral strain to linear strain is termed as the Poisson's ratio bulk modulus modulus of elasticity shear modulus

Poisson's ratio

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

margin

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.

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

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.

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

Souders Brown equation is used for the calculation of the __________ in a continuous distillation column. a) diameter of the bubble cap column b) diameter of the seive plate column c) tray pressure drop d) residence time in the downcomer for the disengagement of entrained vapour

a) diameter of the bubble cap column

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 1 < 1 >1 equal to the order of reaction

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'.

d) both 'b' & 'c'.

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).

a) less than arithmetic mean value.

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 bending deformation shear elongation

bending

__________ closure is the weakest enclosure for cylindrical vessels. Hemispherical Torispherical Conical or flat plate Elliptical

Conical or flat plate

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

Murphree plate efficiency.

Which of the following does not figure in the list of seven substances selected for international temperature scale? Ice (F.P) and steam (B.P) Oxygen and sulphur (B.P) Antimony and silver (F.P) Zinc (B.P) and mercury (F.P)

Zinc (B.P) and mercury (F.P)

A constant volume gas thermometer employing __________ is used to measure sub-zero (i.e., < 0° C) temperature. helium hydrogen nitrogen none of these

helium

pH meter has one cell two cells three cells no cell

two cells

Routh test a) criterion provides information about the actual location of roots. b) cannot be used to test the stability of a control system containing transportation lag. c) criterion is not applicable to systems with polynomial characteristic equation. d) can not determine as to how many roots of the characteristics equation have positive real roots.

b) cannot be used to test the stability of a control system containing transportation lag.

When a bare thermocouple is covered by a protective sheath, the response becomes a) faster and oscillatory. b) faster and non-oscillatory. c) slower and oscillatory. d) slower and non-oscillatory.

d) slower and non-oscillatory.

INDIABIX-PROCESS EQUIPMENT AND PLANT DESIGN Flashcards

(215 cards)