SP Flashcards
(30 cards)
In binary distillation, the separation of the components is easier if the relative
volatility (α) is ______.
a. α»_space;1
b. α «1
c. α =1
d. none of these
A. α»_space;1
In a binary distillation column, if the feed contains 40% mole vapour, the q line will have a slope of ______. (solution required)
a. 1.5
b. -0.6
c. -1.5
d. 0.6
C. -1.5
For a fixed number of ideal stages in a distillation column, as the reflux ratio is
increased, the difference in composition between the top and the bottom product
streams _____.
a. Increases
b. Decreases
c. Remains unaffected
d. Passes through a maximum
A. Increases
In distillation column design, the McCabe-Thiele procedure is inadequate and a Ponchon-Savarit procedure is needed when______.
a. Saturated feed is not used
b. An azeotrope forms
c. The latent heats of vapourization of the more and less volatile components are
greatly different
d. A total condenser is used
D. A total condenser is used
What is the boiling point of benzene-toluene mixture under atmospheric pressure if
the mixture contains 0.682 mole fraction toluene?
a. 100 degC
b. 95 degC
c. 89 degC
d. 98 degC
D. 98oC
What is the boiling point of benzene-toluene mixture under atmospheric pressure if
the mixture contains 0.682 mole fraction toluene? When the resulting vapor is condensed, the liquid composition contains how much benzene (mole fraction)?
a. 0.532
b. 0.83
c. 0.425
d. 0.18
A. 0.532
In vacuum distillation, substance boils at ____.
a. Its exact temperature
b. Temperature slightly above its normal boiling point
c. A temperature below its normal boiling point
d. Under high pressure
C. A temperature below its normal boiling point
Calculate the vapor pressure of a solution of 74g benzene in 48.8g toluene at 25 degC.
a. 9.5 kPa
b. 8.5 kPa
c. 6.5 kPa
d. 10.5 kPa
A. 9.5 kPa
Calculate the relative volatility of the above solution.
a. 4.02
b. 3.35
c. 6.9
d. 11.16
B. 3.35
The estimated minimum number of stages for a binary distillation system with
relative volatility of 2.35, having the lighter component at 0.98 in the distillate and 0.045 in the bottoms is _____.
a. 9
b. 6
c. 7
d. 5
A. 9
A filtration is carried out for 10 minutes at a constant rate in a leaf filter and thereafter it is continued at constant pressure. This pressure is attained at the end of the constant rate period. If one quarter of the total volume of the filtrate is collected during the constant rate period, what is the total filtration rate time? Assume the
cake is incompressible and the filter medium resistance is negligible.
85 min
What is the fraction of the volume of voids over the total volume of the filter cake?
Porosity
Volume of the filtrate collected is 1 gal when the filtration rate is 1.5gpm and it is 5 gal when the filtration rate is 0.6gpm. Calculate the volume collected when the filtration rate is 0.55 gpm. Assume constant-pressure filtration.
5.59
Volume of the filtrate collected is 1 gal when the filtration rate is 1.5gpm and it is 5 gal when the filtration rate is 0.6gpm. Calculate the volume collected when the filtration rate is 0.55 gpm. Assume constant-pressure filtration. What is the total volume of the filtrate collected in 15 min?
6.96
A plate and frame press delivers 50 liters of filtrate in an hour at constant pressure of 50 psig. The washing time using 50 L of wash water is _____.
4h
Calculate the sphericity of a cylinder of diameter 1cmand height 3 cm.
0.779
Find the sphericity of a cube of Vp=a3, Ap= 6a2 and c= a3.
0.806
Which of the following is not an example of adsorption?
a. Recovery and separation of pharmaceuticals
b. Purification and recovery processes for gases and liquids
c. Activated carbon-based applications
d. Nitrogen from air by PSA using carbon molecular sieve
A. Recovery and separation of pharmaceuticals
What is false about sedimentation of particles in a concentrated suspension?
a. If a significant size range of particles is present, the large particles are settling
to a suspension of smaller ones so that the effective density and viscosity of the fluid are increased.
b. The upward velocity of the fluid displaced during settling is appreciable in a concentrated suspension.
c. The apparent settling velocity is more than the actual velocity to the fluid.
d. The velocity gradients in the fluid close to the particles are increased as a result
of the change in the area and shape of the flow spaces.
C. The apparent settling velocity is more than the actual velocity to the fluid
Square plates with 0.0123 cm thickness and 0.0645 square cm are randomly falling through a liquid with a density of 55 lb/ft3 with a μ=15 centipoise. The SG of plates is 3.0, what is its settling velocity?
7.2 cm/s
How many “g” can be obtained in a centrifuge which can spin a liquid at 2000 rev/min at a maximum radius of 10 cm?
450
A particle “A” of diameter 10 microns settles in an oil of SG 0.9 and viscosity of 10 poise under Stokes Law. A particle “B” with diameter 20 microns settling in the same oil will have a settling velocity of _____.
Four times as that of A
The US Standard Sieve series is equivalent to a 24 mesh Tyler Standard is _____ microns.
707
A random handful of silica particles ranging in size from 28 mesh to 200 mesh is thrown to a very deep body of water (without tides or turbulence).
Data:
Viscosity of water= 0.01 poise
Density of silica= 2.65 g/cm3
mesh= 0.0589 cm
200 mesh= 0.0074 cm
The distance between the largest and the smallest particles after 10 min is _____.
4700 cm
