Separation Process Flashcards
The unit operation by which soluble components of a liquid mixture are dissolved in a liquid immiscible with the insoluble component is
Solvent Extraction
The most commonly used leaching solvent in the vegetable oil industry
Hexane
Leaching of sugar from sugar beets is done using?
Hot water
Equipment used for extraction of oil from oilseed
Bollman extractor
Radioactive nuclear waste is treated in
Pulsed column extractor
Equipment used to process uranium and gold ore (or mineral processing)
Pachuca tanks
In a counter-current extractor, as the axial mixing increases, the extraction efficiency
Decreases
Acetic acid will be most economically separated from a dilute solution of acetic acid in water by what method?
Solvent Extraction
Liquid-liquid extraction is based on the differences in?
Solubility
It is a more efficient method of LLE
Repeated small washing
The solvent used in liquid extraction should not have a high latent heat of vaporization because?
Its recovery cost by distillation maybe prohibitively high
Solvent extraction is the terminology applied to the liquid-liquid extraction, which is preferred for the separation of the components of liquids when
Extracting solvent is cheaply & abundantly available
In a counter-current liquid extractor
Only one of the liquids may be pumped at a desired rate
Antibiotics are best handled in a?
Podbielniak extractor
A solution that follows Raoult’s law most closely
A solution of benzene, toluene, and oxylene
Pure liquid is also known as
Subcooled liquid
Pure vapor is also known as
Superheated
The boiling point diagram is affected by what property?
Pressure
The ease of difficulty of separating components by distillation is determined by the
Relative volatility
The relative volatility of most ideal binary solutions is greatly affected by what property?
Temperature
When the relative volatility of two miscible components is close to 1, it can be separated by
Extractive distillation
The physical separation of components in a miscible mixture by simultaneous evaporation and condensation is
Distillation
In batch distillation, the boiling point of the distillate product compared to the residue is?
Lower
Increasing the operating pressure of a distilling column affects separation in what way?
Makes separation difficult
One mol feed of a binary mixture of a given composition is flash vaporized at a fixed T and P. If Raoult’s Law is obeyed, then changing the feed composition would affect
The fraction vaporized but not the product composition
Steam distillation is used to
Avoid thermal decomposition of a component
The amount of steam required per unit quantity of distillate in case of steam distillation will be reduced by what method?
By raising the temp and lowering the total pressure
In distillation, the cooled liquid stream returned to the column to a cool plate stage is called
Reflux
In distilling column, the highest pressure will be at the?
Bottom
A heat transfer equipment used to convert vapor to liquid
Condenser
A reboiler provides heat to the
Bottom of the distilling column
The temperature in a distilling column, from bottom to top (increases or decreases)?
Decreases
Rose oil is extracted from rose leaves using ___ distillation
Steam distillation
When the solvent dissolves very little solute then
A large quantity of solvent is required to extract the solute
An ideal single-stage extraction process is used to treat 100 mol/s of an organic feed solution. The solute concentration in this solution is reduced from 0.5 mol % to 0.1 mol %. A pure solvent S is used. To reduce the solvent requirement by half for the same separation
Use another pure solvent S* whose partition coefficient is twice that of S
The triangle whose one corner coincides with the enriching line and the outer corner is on the stripping line is called the
Feed plate
Flash distillation is suitable for the separation of what kind of components?
Components with very wide boiling points
Relative volatility varies with the concentration of components for an ideal solution. The relative volatility of a binary mixture may be defined as the ratio of vapor component ‘A’ to that of component ‘B’ when
Vapor phase obeys Dalton’s law and liquid phase obeys Raoult’s law
Leaching of coarse solid lumps is also termed as
Percolation
Large scale usage of flash distillation is practiced in what industry?
Petroleum Refining
In an operating distillation column, the
Driving force for the vapor flow is the pressure drop, as the pressure decreases gradually from the bottom to the top of the column
In case of steam distillation, the steam leaving the liquid is not completely saturated with distillate vapor, because
Mixing of steam with the material being vaporized is not so intimate as to result in equilibrium condition
For a binary mixture distillation process, the degree of freedom is 2. However, if the pressure is fixed in this process, the number of independent variables in this process will be
1
The theoretical minimum reflux ratio in the distillation column is attained if the column has
Infinite number of plates
Leaching Perry’s Chapter
18
LLE Perry’s Chapter
15
Distillation Perry’s Chapter
13
Alternative Separation Process Chapter sa Handbook
20
Fenske’s equation for determining the minimum number of
theoretical stages in distillation column holds good, when the
a. relative volatility is reasonably constant.
b. mixture (to be separated) shows negative deviation from
ideality.
c. mixture (to be separated) shows positive deviation from
ideality.
d. multicomponent distillation is involved.
A.
In a distillation column, with increase in the reflux ratio, the heat removed in the cooler
Increases
Inside the distillation column, the
a. driving force for the vapor flow is the pressure drop.
b. liquids are not always at their bubble points.
c. pressure increases gradually from bottom to the top of the
column.
d. none of these
A.
On moving the feed line (q-line) from saturated liquid feed (vertical position) to saturated vapor feed (horizontal feed), if the
slope of both the operating lines are to be increased, then it will
result in
a. greater degree of separation with a fixed number of trays
b. increased reboiler load
c. increased reflux ratio
d. none of these
C.
In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of
a. area between operating line and 45° diagonal x-y diagram
b. condenser and reboiler surfaces
c. tower cross-section
d. none of these
A.
In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of
a. area between operating line and 45° diagonal x-y diagram
b. condenser and reboiler surfaces
c. tower cross-section
d. none of these
A.
Overall efficiency of the distillation column is
the ratio of number of ideal plates to actual plates
Pick out the correct statement.
a. Ponchon-Savarit method is more accurate than McCabe-
Thiele method to determine the number of theoretical stages
required for the separation of non-ideal binary system by
distillation.
b. A sharp decrease in pressure drop is an indication of flooding
in a distillation column.
c. Solvent used in extractive distillation should be of high volatility.
d. Flash distillation is suitable for separating components which
have very close boiling temperature.
A.
Pick out the correct statement.
a. The slope of the stripping line is always less than unity.
b. For a given separation in a binary distillation column, with
increase in reflux ratio (above the minimum reflux ratio), the fixed
cost of the distillation column first increases and then decreases.
c. In Ponchon-Savarit method of no. of theoretical plate
determination, the stripping and rectifying operating lines are
vertical at total reflux.
d. Kremsor-Brown-Souder’s equation is used to calculate the
efficiency of a plate tower.
C.
Design calculation for multiple component distillation is done by
tray to tray calculations
Pick out the wrong statement:
a. Reboiler is not used in open steam distillation.
b. The separation of solutes of different molecular sizes in a liquid solution by use of a suitable membrane is called dialysis.
c. Freeze drying is used for the drying of fish.
d. Fenske-Underwood equation is used for calculating theoretical
number of plates in a distillation column at normal operating reflux condition.
D.
In extractive distillation, solvent is
added to alter the relative volatility of the mixture
Solvent used in extractive distillation
a. is of low volatility.
b. forms a low boiling azeotrope.
c. forms a high boiling azeotrope.
d. does not alter the relative volatility of the original components
B.
Pick out the wrong statement.
a. Critical moisture content is not a property of the material itself.
b. A sharp increase in pressure drop gives an indication of the
flooding in a distillation column.
c. Separation of components is not possible in liquid extraction, if
selectivity is unity.
d. Dehydration of ethyl alcohol is most economically done by
molecular distillation at very high vacuum.
D.
Azeotropic distillation is employed to separate
Constant boiling mixture
The equilibrium liquid composition compared to the vapor
composition in case of azeotropic mixture is
Same
Pick out the wrong statement.
a. The mole fraction of solute is directly proportional to the
molality of a ‘dilute’ solution.
b. For a non-reacting binary mixture of ideal gases, the partial
pressure distribution of both components is nonlinear in the case
of steady state unimolal unidirectional diffusion.
c. Azeotropes obey Raoult’s law at all temperature.
d. The relative volatility of a binary mixture at the azeotropic
composition is 1.
C.
Pick out the system with minimum boiling azeotrope at 1 atm.
a. benzene-toluene c. hydrochloric acid-water
b. ethyl alcohol-water d. all of these
C.
Which of the following binary systems is an example of a
maximum boiling azeotrope?
a. water-hydrochloric acid
b. acetone-carbon disulfide
c. water-ethyl alcohol
d. n-heptane-n-octane
C.
