Process Equipment and Plant Design Flashcards
Fresh water carrying pipelines in chemical industries are coloured with __________ color.
sea green
Which of the following material is seldom used for pressure vessel construction?
Rimmed still
The ratio of shear stress to shear strain is called
shear modulus
25 percent cut segmental baffle means that the baffle
height is 75% of the I.D. of the shell.
Liquid/petroleum fuel storage tanks are built underground (as in the case of petrol pumps) when the storage capacity is less than __________ kilolitres.
45
Le/D for fully open globe value may be around
300
Lug support is
A. the most suitable for thick vertical vessels.
B. same as bracket support.
C. usually provided for vessels of much smaller height than skirt-supported vessels.
D. all (a), (b), and (c).
D
Pick out the WRONG statement pertaining to the use of valve tray, sieve tray, and bubble cap trays in a continuous distillation column.
A. Bubble cap trays though the most expensive are the best in situations, where low vapor rates is to be handled and a positive liquid seal is essential at all flow rates.
B. Murphree efficiency of all three trays are nearly equal, however, the peak efficiency is generally higher for sieve and valve trays than the bubble cap.
C. Maintenance costs for valve and sieve trays are comparatively more than bubble cap trays due to their relatively complicated construction features.
D. Valve trays have the highest turndown ratio (i.e. the ratio of the highest to the lowest vapor flow rates) and thus provide the maximum flexible operating range.
C. Maintenance costs for valve and sieve trays are comparatively more than bubble cap trays due to their relatively complicated construction features.
With the increase in the number of shell passes, the value of F_T
increases
Holes of a sieve tray are arranged in a triangular pitch of __________ times the hole diameter.
2.5 to 5
In the 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
The stress developed in a material without any permanent set is called the
elastic limit
In a shell and tube heat exchanger, the ‘tube pitch’ is defined as the
shortest centre to centre distance between adjacent tubes.
Which of the following is not a valid assumption in continuous binary distillation for calculating the number of equilibrium stages by Mc-Cabe-Thiele’s method?
A. Sensible heat changes for vapor & liquid are negligibly small.
B. Reflux is not a saturated liquid.
C. Molar latent heat of the two components is equal.
D. Heat of mixing of normal liquid is assumed to be zero.
B. Reflux is not a saturated liquid.
Overall distillation column efficiency for most of the refinery columns can be given by (for μ = 0.07 - 1.4 cp and relative volatility < 4) (where η = overall column efficiency, % μ = molal average viscosity of feed at average column temperature and pressure, cp Δp = pressure drop per tray, psi)
η = 17 - 61.1 log μ
The value of the fouling factor depends upon the
A. characteristic of the process fluid.
B. velocity of process fluid containing suspended solids.
C. suspended solids in the fluid.
D. all (a), (b) and (c).
D.
In the case of a bubble cap distillation column of diameter greater than 1.2 metres, the cap diameter is roughly about __________ cms.
10
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
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)
In a heat exchanger, shell side fluid velocity can be changed by changing the tube
layout and pitch
Where does the maximum tensile strength occur in a thick cylindrical vessel subjected to internal pressure?
At the inner surface.
It is not desirable to design a heat exchanger for LMTD correction factor, FT, of less than
0.80
A rivetted joint does not fail by __________ of rivets.
A. tearing
B. shearing
C. tearing of the plate across a row
D. none of these
D
Triangular pitch tube layout as compared to square pitch in a shell and tube heat exchanger
permits the use of more tubes in a given shell diameter.