CPI, Process Control and Design Flashcards
(170 cards)
Back-trapping in a distillation column results due to
A. low gas velocity
B. excessive liquid gradient over the tray
C. high gas velocity
D. low reflux ratio
B. excessive liquid gradient over the tray
The minimum plate spacing in most of the petroleum refinery distillation columns (of diameter 73 ft) is normally
A. 6’’
B. 12’’
C. 18’’
D. 34’’
C. 18’’
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
The most common standard size of bubble caps used in industrial operation is:
A. 1” diameter cap with 0.5” diameter riser
B. 6” diameter cap with 1” diameter riser
C. 6” diameter cap with 4” diameter riser
D. 4” diameter cap with 5” diameter riser
C. 6’’ diameter cap with 4’’ diameter riser
High pressure fluid in a shell and tube heat exchanger should preferably be routed through:
A. tubes to avoid the expense of high pressure shell construction
B. Shell side for smaller total pressure drop
C. Shell side of the flow is counter-current and tube side if the flow is co-current. D. shell side for larger overall heat transfer co-efficient
A. tubes to avoid the expense of high pressure shell construction
When one of the fluids is highly corrosiv e and has fouling tendency , it should:
A. preferably flow inside the tube for its easier internal cleaning
B. preferably flow outside the tube
C. flow ate 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
In a shell and heat tube ex changer, the clearance of the tube is generally :
A. not less than one-fourth of the tube diameter or 3/16
B. more than the tube diameter
C. equal to the tube diameter
D. more in case of triangular pitch as compared to the square pitch tube layout
A. not less than one-fourth of the tube diameter or 3/16
For a given fluid as the pipe diameter increases, the pumping cost:
A. decreases
B. increases
C. remains unaffected
D. may increase or decrease depending upon whether the fluid is Newtonian or non-Newtonian
A. decreases
Which of the following is the most common baffle used in industrial shell and tube heat exchange?
A. 75% out segmental baffle
B. orifice baffle
C . 25% out segmental baffle
D. disk and doughnut baffle
C . 25% out segmental baffle
Twenty five percent out segmental baffle means:
A. height is 75% of the I.D. of the shell
B. spacing is 25% of its height
C. height is 25% of the I.D of the shell
D. width is 25% of the height
A. height is 75% of the I.D. of the shell
In most of the shell and heat tube exchanger, the tube pitch is generally:
A. less than the diameter of the tube
B. 2.5 times the tube diameter
C. 1.25-1.50 times the tube diameter
D. one-fourth of the tube diameter
C. 1.25-1.50 times the tube diameter
Floating head heat exchangers are used for:
A. heat transfer between corrosive fluids
B. cases where temperature difference between the shell and the tubes is more (>50 C) C. co-current and transfer systems
D. counter-current heat transfer systems
B. cases where temperature difference between the shell and the tubes is more (>50 C)
In a double pipe (concentric) heat exchanger, the hydraulic radius for heat transfer (for a fluid flowing through the annulus) would be:
A. same as that for the fluid flow
B. less than that of the fluid flow
C . more than that of the fluid flow
D. D2 – D1 (D1 and D2 are I.D. of outer and inner pipes respectively)
C . more than that of the fluid flow
Pouring factor must be included in the calculation of overall 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
In the case of the shell and heat tube exchanger, the logarithmic mean temperature difference:
A. is always less than arithmetic average value
B. is always more than arithmetic mean value but more than geometric mean value
C . is alw ay s less than arithmetic mean v alue but more than geometric mean v alue
D. May be either more or less than geometric mean and arithmetic mean value depending upon whether the flow of stream is concurrent or counter current
A. is always less than arithmetic average value
Joint efficiency for a seamless pipe is:
A. 1
B. 0.65
C. 1.2
D. 0.5
A. 1
In the design of a paddle agitator, the ratio paddle diameter to tank diameter is normally taken as:
A. 0.1
B. 0.6
C. 0.25
D. 0.5
B. 0.6
The ratio propeller agitator diameter o tank diameter is normally taken as:
A. 0.15-0.30
B. 0.5-0.65
C. 0.75-0.85
D. 0.50-0.90
A. 0.15-0.30
The minimum baffle height should be:
A. equal to the impeller diameter
B. twice the diameter
C . twice the impeller diameter
D. 3⁄4 of the tank height
C . twice the impeller diameter
Leg support is meant for:
A. large horizontal cylindrical vessels
B. small vessels
C. tall but empty vessels
D. thick walled tall vessels
B. small vessels
Skirt support is suitable for:
A. small horizontal vessels
B. tall vertical vessels
C. large horizontal v essels
D. thick walled small v ertical v essels
B. tall vertical vessels
Saddle support are used for supporting:
A. horizontal cylindrical vessels
B. thick walled vertical vessels
C. tall vertical vessels
D. thick spherical vessels
A. horizontal cylindrical vessels
A replica of a commercial scale plat:
A. lab scale
B. bench scale
C. pilot scale
D. small scale
C. pilot scale
Vertical valves are not supported by:
A. brackets
B. skirts
C. column
D. saddles
D. saddles