Process Equipment and Plant Design Flashcards
(189 cards)
1
Q
Tube height in a calendria type evaporator is normally less than __________ metres.
A
2
2
Q
For a 25 mm hole drilled in plates to be rivetted, the shank diameter of the rivet should be __________ mm.
A
23
3
Q
Pressure differential maintained across a continuous rotary vacuum filter is in the range of __________ mm Hg column.
A
250-500
4
Q
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
5
Q
Le/D for 90° elbow (medium radius) and 90°square elbow would be respectively around
A
25 and 60
6
Q
In hydrostatic testing of welded pipe (for leakage, strength etc.) the ratio of minimum hydrostatic test pressure to internal design pressure is around
A
1.5
7
Q
Frame thickness in the plate and frame filter press is normally in the range of __________ inches.
A
0.25 to 8
8
Q
Cylinderical shell thickness of rotary drier is generally __________ mm.
A
6-8
9
Q
The distance between the centre of a rivet hole to the nearest edge of the plate is called
A
margin
10
Q
A minimum clearance of about __________ mm is maintained between the distillation column wall and the bubble cap.
A
38
11
Q
Bracket supports are used for horizontal shell, while saddle support is used for vertical shell.
A
Wrongggg
12
Q
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
13
Q
Le/D for a Tee (used as elbow, entering run) would be around
A
60
14
Q
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
equal to
15
Q
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
16
Q
__________ closure is the weakest enclosure for cylindrical vessels.
A
Conical or flat plate
17
Q
Cylindrical storage tanks used for the storage of volatile liquids (e.g., naphtha) have __________ roofs.
A
floating
18
Q
In a stainless steel seive tray, the minimum hole diameter is equal to 10 times the plate thickness.
A
Wrongggg
19
Q
In the downcomer of a distillation column, the minimum recommended residence time is about __________ seconds.
A
5
20
Q
For identical situation, condensing film coefficient in case of a horizontal condenser is almost __________ the value expected in case of vertical condenser.
A
thrice
21
Q
Diameter of rivet hole (d, mm) and the plate thickness (t, mm) are related by Unwin’s formula as
A
d=1.6√T
22
Q
A binary liquid azeotropic mixture has boiling point lower than either of the components, when it shows __________ deviation from Raoult’s Law.
A
positive
23
Q
In which of the following evaporators, steam is fed inside the tube while the liquor is outside the tube ?
A
Horizontal tube evaporator
24
Q
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
2^0.8
25
In a multipass shell and tube heat exchanger, the baffles on shell side is primarily provided for
creating turbulence
26
For turbine agitator, the impeller diameter is about
0.3 to 0.5d
27
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.
increase by 2^1.6
28
Which of the following is the most common type of baffle used in industrial shell and tube heat exchanger ?
25% cut segmental baffle.
29
What is the minimum recommended ligament for square pitch arrangement in case of heat exchangers ?
6.5 mm
30
Centre to centre distance between two consecutives rivets in a row is called the pitch.
Correctuee
31
Safety valves are provided in chemical equipments to guard against excessive
pressure/pressure fluctuation
32
The equivalent diameter for pressure drop is __________ that for heat transfer.
smaller than
33
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.
80
34
The approximate liquid depth in an agitation tank is equal to (where, d = tank diameter)
d
35
Baffle width is normally taken as __________ times the tank diameter.
0.1-0.12
36
A cylinderical pressure vessel of volume 6 πm3 has to be designed to withstand a maximum internal pressure of 10 atm. The allowable design stress of the material is 125N/mm2 and corrosion allowance is 2 mm. The thickness of the vessel for a length/diameter ratio of 3 will be close to
10 mm
37
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)
4 A/P
38
Lug support is meant for supporting __________ vessels.
small
39
In case of 1.5" heat exchanger tubes, the inside flow area __________ with decrease in BWG.
decreases
40
Cylindrical pressure vessels in horizontal condition is generally supported on a __________ support.
saddle
41
Pressure drop per tray in the atmospheric distillation column is about __________ psi.
0.07-0.12
42
Welded joint efficiency in the design of chemical process equipment is taken as
0.85
43
The thickness of segmental baffles (25 -35% cut truncated plates usually) is generally __________ the tube wall thickness.
twice
44
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
1
45
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.
considerably more than 9
46
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.
2.5 to 4.0
47
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'.
wronggggggg
48
Bubble cap diameter used for the distillation column having diameter ranging from 1.5 to 4.5 metres is about __________ mm.
100
49
With increase in the number of shell passes, the value of FT
increases
50
Holes of a sieve tray are arranged in triangular pitch of __________ times the hole diameter.
2.5 to 5
51
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.
5-11
52
In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about __________ cms.
10
53
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.
8
54
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
(1.2)^5/3
55
It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than
0.80
56
Bracket supports are the most suitable for supporting __________ vessels.
thick walled vertical
57
Two iron pipes of the same nominal diameter but different schedule numbers will have the same
inside diameter
58
Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m2.°C.
7500
59
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.
20
60
In chemical process equipments, the conical bottom heads used, usually has an apex angle of
60°
61
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.
75
62
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
less
63
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.
20-40
64
__________ tray arrangement is recommended for distillation column having diameter upto 4 ft.
Cross flow
65
The operating pressure drop range in a bag filter is about __________ mm water gauge.
50-150
66
Packed towers are generally preferred over plate towers, if the liquids have a foaming tendency.
Correctueer
67
Wall thickness of schedule 40 pipe as compared to that of schedule 80 pipe is
less
68
It is used for high viscosity liquor having large rate of scaling.
Wrong
69
Speed of the drum of the rotary vacuum filter normally ranges from __________ rpm.
0.1 to 2
70
dished bottom vessel has very high power consumption.
Wrongggg
71
Holes of a sieve tray are arranged in triangular pitch of __________ times the hole diameter.
2.5 - 5 (second lower)
72
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.
5-11 (second lower)
73
In case of bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about __________ cms.
10
74
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.
8
75
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
(1.2)^5/3
76
It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than
0.80
77
Steam side heat transfer co-efficient for design consideration under ordinary condition can be assumed to be about __________ kcal/hr.m2.°C.
7500
78
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.
20
79
In chemical process equipments, the conical bottom heads used, usually has an apex angle of
60°
80
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.
75
81
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
less
82
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.
20-40 (second lowest)
83
__________ tray arrangement is recommended for distillation column having diameter upto 4 ft.
Cross flow
84
The operating pressure drop range in a bag filter is about __________ mm water gauge.
50-150 (second lowest)
85
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
decreases
86
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.
15-30
87
In packed towers provided with saddle packing, liquid redistributors are positioned at every __________ times column diameter or 6 metres whichever is less.
5-8
88
Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter )
0.2D
89
The maximum liquid gradient over a tray must not exceed
0.5" - 1.25"
90
Speed of industrial paddle agitator ranges from __________ rpm.
20-100 (second lowest)
91
With increase in pressure drop (for a given particle size), the dust collection efficiency of a cyclone separator will
increase
92
Generally, no corrosion allowance in wall thickness of a part is required, if the thickness is more than __________ mm.
30
93
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.
0.1 to 0.25
94
In a distillation column, the minimum residence time for liquid in the downspout is about __________ seconds.
8
95
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.
1.25 to 3.125 (second lower)
96
Length to diameter ratio of most rotary driers is in the range of
4 to 10 (second lower)
97
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.
19 (second lower)
98
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.
600 (second lower)
99
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
100
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
decreases upwards
101
In the design of a paddle agitator, the ratio paddle dia/tank dia is normally taken as
0.8 (second lower)
102
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.
damaging
103
Hole diameter of the seive trays in the distillation column ranges from __________ mm.
3 to 1.25
104
Factor of safety (i.e., overdesign factor) in heat transfer equipments is about __________ percent more than the actual/theoretical design factor.
15-20 (second lower)
105
The minimum shell thickness for tank ≤ 15 metres diameter is limited to __________ mm, for reasons of elastic stability.
5
106
Brass valves are usually made for pipe sizes __________ inches.
≤2 (second lower)
107
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
remains same
108
In most of the shell and tube heat exchangers, the tube pitch is generally __________ the tube diameter.
1.25-1.50 times
109
In a distillation column, bubble caps are located on trays with a pitch of __________ times the outside diameter of the caps.
1.3 to 2
110
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).
650
111
Normal screwed fittings are used for pipes upto a diameter of __________ inches.
3
112
Maximum acceptable total liquid gradient over a tray is about __________ mm.
12.5
113
In case of a 'thin' pressure vessel, the ratio of its diameter to wall thickness is
> 10
114
In the agitators, the power required will be changed with the increase of diameter of agitator (D) as
D^5
115
Apex angle of conical heads used in the bottom heads of chemical process equipments is usually
60°
116
A pressure vessel is said to be made of 'thick' shell, if the ratio of its diameter to wall thickness is
10
117
Tube side heat transfer co-efficient for turbulent flow of liquid through tubes is proportional to
G^0.8
118
Circumferential (hoop) stress in a thin cylindrical vessel under internal pressure is __________ the longitudinal stress.
twice
119
For storing hazardous chemicals in large storage tanks, the minimum safe distance between the two tanks should range between __________ times the tank diameter.
1 to 1.5
120
The ratio of tube length to shell diameter in case of liquid shell and tube heat exchanger ranges from
4 to 8
121
What is the slope of the operating line in the stripping section of a distillation column ?
> 1
122
_________ shaped roof is most commonly used for cylindrical tanks.
Cone
123
In a thin cylindrical shell, the hoop stress is __________ stress.
circumferential tensile
124
Commercial packed scrubbers are normally designed for a pressure drop range of __________ mm water coloumn per metre of packed height.
17-34
125
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.
1.5 to 2.5
126
The difficulty of liquid distribution in packed towers is accentuated, when the ratio of tower diameter to packing diameter is
< 7
127
With increase in temperature drop (in a shell and tube heat exchanger), the LMTD correction factor, FT
decreases very rapidly
128
The normal range of velocity of steam in pipes is __________ m/sec.
80-100
129
________ dished head is the strongest of all.
Hemispherical
130
Minimum baffle spacing recommended in a shell and tube heat exchanger is equal to
5 cms
131
Theoretically calculated diameter of the stripping section of the continuous rectification column is __________ that of the enriching section.
more than
132
Hold up of material in a operating rotary drier is in the range of
0.05 to 0.15
133
The testing pressure of storage tanks and pressure vessels designed as per Indian standard codes should be about __________ times.the design pressure.
1.5 to 2
134
The ratio of down take area to cross-sectional area of the tube, for calendria type evaporator ranges from
0.5 to 1
135
_________ tower is the most suitable gas-liquid contacting device involving highly corrosive fluids.
Packed
136
The wall thickness of thin cylindrical shell with hemispherical ends is __________ that of the spherical ends.
more than
137
Minimum tube pitch recommended for shell and tube heat exchangers is about __________ times the outside diameter of the tube.
1.25
138
Liquid redistribution should be done in a packed tower packed with raschig rings every 6 metres or __________ times the column diameter, whichever is lower.
2.5-3.0
139
Slope of countercurrent flow rotary drier is in the range of __________ meter/metre.
0 to 0.8
140
In case of saddle packing (e.g., berl and intralox saddles), the maximum size of the packing should not exceed __________ of the column diameter.
l/15th
141
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
1.5 d
142
The normal range of velocity of water in pipes is __________ m/sec.
1-2
143
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.
10 to 20 (second lowest)
144
Heat transfer co-efficient for a horizontal condenser as compared to a vertical condenser operating under similar conditions is
about 3 times
145
The longitudinal stress induced in a thin walled cylinderical vessel under internal pressure is
pd/4t
146
In case of plain carbon steel, butt welded joints are used for shell plate thickness ≤ __________ cms.
3.8
147
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.
4
148
Hoop (circumferential) stress induced in a thin walled 'Horton Sphere' used for the storage of liquid ammonia under pressure is
pD/2t
149
The ratio, propeller agitator dia/tank dia is normally taken as
0.15-0.30
150
Maximum plate efficiency is achieved in case of __________ flow.
cross
151
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.
one fourth
152
The ratio for the rate of washing to the final rate of filtration in a washing type of plate and frame filter is
0.25
153
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
1.5-2.5
154
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
0.3
155
Typical static submergence for bubble cap plate column operating at atmospheric pressure may be around
0.5"
156
The length of straight rectangular weir used on cross-flow trays is generally __________ the column diameter.
0.6-0.8 times
157
Le/D for couplings and unions would be
negligible
158
What is the slope of the operating line in the rectifying section of a distillation coloumn ?
<1
159
The minimum plate spacing in most of the pertroleum refinery distillation columns (of dia > 3 ft) is normally __________ inches.
18
160
Joint efficiency (J) for a seamless pipe is
1
161
The shell side pressure drop in a shell and tube heat exchanger is maximum for __________ baffle.
orifice
162
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 ?
0.8
163
Diameter of bubble caps used in high pressure columns is __________ as compared to that used in identical vacuum columns.
more
164
The ideal size of round bubble caps to be used in industrial distillation column having a diameter of 3-6 metres is __________ cms.
15
165
Lap joints are preferred for plates having thickness __________ mm.
> 3
166
In a distillation column, minimum clearance to be maintained betweeen the overflow weir and the last row of the bubble caps is __________ cms.
7.5 (second lowest)
167
Which of the following lengths of heat exchanger tubes are normally not used in practice ?
10 metres
168
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
10000
169
Equivalent diameter for heat transfer calculation for a duct of square cross-section having each side as 'd' will be
d
170
For high pressure process equipments/vessels, the connected nozzle should be
flanged
171
172
In inclined long tube vertical evaporators, the tubes are inclined at an angle of
45 deg
173
In a continuous distillation column, the optimum reflux ratio ranges from __________ times the minimum reflux ratio.
1.1 to 1.5
174
Generally, as the length of the liquid path on a tray is increased beyond 5 ft, the overall column efficiency
increases
175
In packed absorption tower, onset of flooding usually occurs at a pressure drop of about __________ mm of water column per metre height of packing.
50-75
176
For pipe flows, head is proportional to __________ at constant capacity (where D = pipe diameter ).
1/D^5
177
The minimum tray spacing in distillation column of diameter less than 3 ft is normally __________ inches.
6
178
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
0.1-0.2
179
Maximum size of the raschig rings used in a packed tower is about __________ of the coloumn diameter.
1/30th
180
Longitundinal stress induced in a thin walled cylindrical storage vessel is
pD/4t
181
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.
thermal
182
The safe distance of habitation from a hazardous chemical plant (TLV of its product < 1000 ppm) should be about __________ kms.
25
183
Normally, the plate thickness of the bottoms and roofs of vertically cylindrical storage vessels as compared to that of the cylindrical shell is
less
184
The practical representative values of HETP for a number of commercial operations lies within a range of __________ metre.
0.4-0.9
185
Of the pressure vessels, with same thickness but different diameters, which one withstands higher pressure ?
Smaller dia vessel
186
Width and depth of grooves in the tube sheet holes normally are __________ inch respectively.
1/8 and 1/64
187
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.
1/10-1/15th
188
Height of the flights in the rotary drier is in the range of
0.08 to 0.12 d
189
Vapor velocity in a distillation column for non-foaming mixture is in the range of __________ times the flooding velocity.
0.6 to 0.7 (second lowest)
