Process Equipment and Plant Design Flashcards
Holes of a sieve tray are arranged in triangular pitch of __________ times the hole diameter.
2.5 to 5
The stress developed in a material without any permanent set is called the
elastic limit
A rivetted joint does not fail by __________ of rivets.
none of these
In a multipass shell and tube heat exchanger, the shell side cross flow area does not depend upon
none of these
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
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
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.
none of these
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
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.
In packed towers provided with saddle packing, liquid redistributors are positioned at every __________ times column diameter or 6 metres whichever is less.
5-8
Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter )
0.2D
Speed of industrial paddle agitator ranges from __________ rpm.
20 to 100
The slope of operating line in the rectifying section of a distillation column is unity, if the reflux ratio is
infinity
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
Floating head heat exchangers are used for the
cases where temperature difference between the shell and the tubes is more (>50°C).
In a distillation column, the minimum residence time for liquid in the downspout is about __________ seconds.
8
Length to diameter ratio of most rotary driers is in the range of
4 to 10
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
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
In the design of a paddle agitator, the ratio is normally taken as
0.8
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
For annular flow of a fluid, the ratio of the equivalent diameter for pressure drop calculation to the equivalent diameter for heat transfer calculation is
d1/(d1 + d2)
The minimum shell thickness for tank ≤ 15 metres diameter is limited to __________ mm, for reasons of elastic stability.
5
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
