S7 Flashcards
Cylindrical storage tanks used for the storage of volatile liquids (e.g., naphtha) have ________ roofs.
floating
Pick out the wrong statement.
none of these.
Pick out the wrong statement.
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.
5
For identical situation, condensing film coefficient in case of a horizontal condenser is almost ________ the value expected in case of vertical condenser.
thrice
Diameter of rivet hole (d, mm) and the plate thickness (t, mm) are related by Unwin’s formula as
d = 1.6 √ t
A binary liquid azeotropic mixture has boiling point lower than either of the components, when it shows ________ deviation from Raoult’s Law.
positive
In which of the following evaporators, steam is fed inside the tube while the liquor is outside the tube?
Horizontal tube evaporator
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
2^0.8
In a multipass shell and tube heat exchanger, the baffles on shell side is primarily provided for
creating turbulence.
For turbine agitator, the impeller diameter is about
0.3 to 0.5 d
In a shell and tube heat exchanger having triangular pitch, the shell side equivalent diameter is given by
4(0.86P^2 - πd^2/4) / πd
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
Pick out the wrong statement.
A 90° welded elbow is diagrammatically represented by
FIGURE
Pick out the wrong statement pertaining to the design of a long tube vertical evaporator.
none of these.
Which of the following is the most common type of baffle used in industrial shell and tube heat exchanger?
25% cut segmental baffle.
What is the minimum recommended ligament for square pitch arrangement in case of heat exchangers?
6.5 mm
Pick out the correct statement
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
pressure/pressure fluctuation
The equivalent diameter for pressure drop is ________ that for heat transfer.
not related with
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
static submergence
Liquid gradient over the tray results due to the
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?
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.
80
The approximate liquid depth in an agitation tank is equal to (where, d = tank diameter)
d
Baffle width is normally taken as __________ times the tank diameter.
0.1-0.12
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
Which of the following packing materials provides for maximum mass transfer?
Cross-partition rings.
__________ of water makes it a widely used coolant in heat exchangers.
High specific heat
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
Fouling factor must be included in the calculation of over all design heat transfer coefficient, when the liquid
containing suspended solids flows at low velocity.
Lug support is meant for supporting __________ vessels.
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.
NH3
Which tube arrangement in a heat exchanger would facilitate highest heat transfer rate?
Triangular pitch.
In case of 1.5” heat exchanger tubes, the inside flow area __________ with decrease in BWG
decreases
Cylindrical pressure vessels in horizontal condition is generally supported on a __________ support.
saddle
Pressure drop per tray in the atmospheric distillation column is about __________ psi.
0.07 - 0.12
Welded joint efficiency in the design of chemical process equipment is taken as
0.85
The thickness of segmental baffles (25 -35% cut truncated plates usually) is generally __________ the tube wall thickness.
twice
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
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
The ratio of linear stress to linear strain is termed as the
modulus of elasticity
__________ head is the most economical for cylindrical vessels designed for operating at high pressure (> 15 atm.).
Ellipsoidal
Bubble cap plate column is
a finite stage contactor.
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
Pick out the wrong statement.
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’.
The force due to wind load acting on a tall vessel depends upon its
all (a), (b) & (c).
Bubble cap diameter used for the distillation column having diameter ranging from 1.5 to 4.5 metres is about __________ mm.
100
