S8 Flashcards
Power required for agitation depends upon the
all (a), (b) and (c).
Tube height in a calendria type evaporator is normally less than ________ metres.
1
Pick out the wrong statement.
A reducer is used to change the direction of a pipe in a straight run.
For a 25 mm hole drilled in plates to be rivetted, the shank diameter of the rivet should be ________ mm.
23
In a shell and tube heat exchanger having square pitch, the shell side equivalent diameter is given by (where, P = pitch, d = outside diameter of the tube)
4 (P^2 - πd^2 / 4) / πd
Optimum economic pipe diameter for fluid flow is determined by the
total cost considerations (pumping cost plus fixed cost of the pipe).
Pressure differential maintained across a continuous rotary vacuum filter is in the range of ________ mm Hg column.
250 to 500
Vertical storage vessels are never supported by ________ support.
saddle
In a double pipe (concentric) heat exchanger, the hydraulic radius for heat transfer (for a fluid flowing through the annulus) would be
more than that for fluid flow.
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)
σ/E
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.
two
What is the slope of the feed line, if the feed to a distillation column is a saturated liquid?
∞
Filtration rate is affected by the
all (a), (b) and (c).
Liquid gradient over a tray can be minimised by
all (a), (b) and (c).
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 Le/D for 90° elbow (medium radius) and 90°square elbow would be respectively around
can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less.
25 and 60
__________ heat exchanger is also known as ‘hair pin type’ exchanger,
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
In hydrostatic testing of welded pipe (for leakage, strength etc.) the ratio of minimum hydrostatic test pressure to internal design pressure is around
1.5
Frame thickness in the plate and frame filter press is normally in the range of __________ inches.
0.25 to 8
Cylinderical shell thickness of rotary drier is generally __________ mm.
6-8
The ratio of lateral strain to linear strain is termed as the
Poisson’s ratio
The distance between the centre of a rivet hole to the nearest edge of the plate is called
margin
Mc Cable Thiele method used for finding theoretical stages in a distillation column assumes that the
all (a), (b) and (c).
A minimum clearance of about __________ mm is maintained between the distillation column wall and the bubble cap.
38
Pick out the wrong statement.
none of these.
Pick out the wrong statement pertaining to shell and tube heat exchanger.
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
short (< 2 m) and housed indoor.
Souders Brown equation given by, U = Kv sqrt ρl - ρv / ρv , is used for the calculation of the __________ in a continuous distillation column.
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
Le/D for a Tee (used as elbow, entering run) would be around
60
Log mean temperature difference in case of multi-pass shell and tube heat exchanger is always
less than arithmetic mean value.
Practical dividing line between a ductile and brittle materials is suggested, when the ultimate elongation is about 5%. Generally, larger the knuckle radius, stronger is the corner torus section of a head. The knuckle radius provided should be less than __________ of the head.
either (a) or (b), whichever is larger
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”).
equal to
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
Scale up problem in design based on the similarity concept takes into account __________ similarity.
all (a), (b) and (c)
__________ closure is the weakest enclosure for cylindrical vessels.
Conical or flat plate
Which of the following efficiencies can be greater than 100%?
Murphree plate efficiency.
