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Packed
The ratio of number of ideal plates to actual plates.
both (b) and (c)
Heat transfer
reduce drying temperature.
higher relative humidity
absorption
both 'a' & 'b'
number of plates is infinity.
partial pressure of the vapour to the vapour pressure of the liquid at gas temperature.
decreases
electrical resistance
specific heat
increase 'S' and decrease 'G'.
1
decreases with decrease in pressure.
both (a) and (b)
Lewis number
line always lies above the equilibrium curve.
total cost first decreases and then increases.
0
Both (a) and (b)
all (a), (b) and (c)
Flow rate of entering liquid
affected more by temperature than that for gases.
Multicomponent distillation.
Wetted wall column
spray chamber
an irreversible phenomenon.
all 'a', 'b' & 'c'.
solvents.
allowable gas and liquid velocities.
any number of components
decreases.
all (a), (b) and (c).
linear crystal growth rate does not depend on the crystal size.
is used for extraction of oil from oilseed.
heat and mass
all 'a', 'b', & 'c'.
increase
Ponchan-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.
vapour pressure of component A to that of component B.
elutriation or elution
surface evaporation of unbound moisture occurs.
71 min
Thermal
concentration
Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column.
Rotary dryer is suitable for drying sticky material.
low pressure drop and low hold up.
> 100
50%
ideal solutions
results due to very low gas velocity.
area between operating line and 45° diagonal x-y diagram.
mass transfer co-efficient.
the overhead product is minimum.
increases
packing may be crushed due to thermal expansion/contraction of the components of the equipments.
same
wetted wall
ethyl alcohol-water
rotary
linearly
Sherwood
0.215
its recovery cost by distillation may be prohibitatively high.
is greater than
litre
less number of trays are required.
exponential
Water-hydrochloric acid.
Peclet
In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux.
Electrodylsis is used in the manufacture of NaOH.
The driving force for mass transfer in a wet solid is its free moisture content.
avoid channelling
free
steam jet ejector with a barometric condenser
increased reflux ratio
Plate
ion-exchange
all (a), (b)&(c)
Azeotropes obey Raoult's law at all temperature.
acetone-carbon disulphide
A solution of benzene, toluene and oxylene.
decreases pressure drop, increases surface area.
both (a) and (b).
both parallel and straight
that of normal condensation.
carbon dioxide from gaseous stream using alkaline solution.
> 1
Fenske-Underwood equation is used for calculating theoretical number of plates in a distillation column at normal operating reflux condition.
heated cylinder
Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum.
large latent heat
raschig
infinity
hot water
both operating and equilibrium lines are parallel.
lift and shower the solids thus exposing it thoroughly to the drying action of the gas.
on heating, a vapor phase will appear ; while on cooling, a solid phase will appear.
none of these.
0.4
absorption factor
both enthalpy and material balances.
always smaller than
operating line always lies below the equilibrium curve.
Infinity
is maximum
10-60
liquid side mass transfer co-efficient should be increased.
integral heat of adsorption.
total reflux
all (a), (b) & (c)
only one of the liquids may be pumped at any desired rate.
None of these
individual mass transfer co-efficient (M.T.C.) in gaseous system.
less
greater than that computed for ideality.
both (a) and (c)
7
affected by pressure.
avoid thermal decomposition of a component.
dilute solutions, over a small concentration range.
marginal decrease in the number of
pure component
Spray dryer
Heating and dehumidification at almost constant wet bulb temperature.
S > 1
In actual practice, absorption is an en-dothermic process, while stripping is an exothermic process.
steam
spouted bed
constant boiling mixture.
∞
more
kinematic viscosity
v
high boiling substances from nonvolatile impurities.
q = 1
drift
1000
diffusivity of solute increases.
molal
both(a) & (b)
smaller than
Pachuka tanks
means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities.
Podbielniak extractor.
infinite
Podbielniak
-1.5
Mechanical agitation is required, if the system has low interfacial tension.
solvent extraction
tray to tray calculations.
interfacial surface between liquid and gas phase should be large.
dependent on the Reynolds number
one of the liquid components has very high affinity towards the solvent.
driving force for the vapour flow is the pressure drop.
Tray drier
insoluble in the liquid
Dew point
temperature
constant boiling point
200-330
freeze
added to alter the relative volatility of the mixture.
pulsed column extractor
Wet bulb
T
Gilliland
incurs smaller pressure drop.
Hexane
none of these
through circulation
agitated vessel
a binary mixture.
a total condenser is used.
gas phase resistance controlled.
number of plates increases.
Spray towers
the fraction vaporised but not the product composition.
steady state equimolar counter diffusion
stready state diffusion for stagnant case.
Packed column (with stacked packing)
liquid
L/G
Wet bulb temperature
can lie above or below the equilibrium curve.
Packed column (stacked)
both 'a '& 'b'
half
molecular velocity and por radius of the catalyst.
flooding
forms a low boiling azeotrope.
T1-Dry bulb temp; T2-Wet bulb temp; T3-Dew point temp.
- ve
both zero and hundred
decreases tray efficiency.
more than
spray
Activated carbon
increases.
Relative volatility of a binary mixture changes appreciably with the minor change in temperature.
increasing temperatures both on the surface and within the solid.
Solvent extraction
Agitated vessels
2
is independent of pressure.
p = P
Lewis
relative volatility
momentum diffusivity/mass diffusivity.
ideal gases
penetration
fluidisedbed
Mechanical draft cooling tower.
For a non-reacting binary mixture of ideal gases, the partial pressure distribution of both components is linear in the case of steady state equimolal counter-diffusion.
gas plus its accompanying vapour at 1 atm. and gas temperature.
pulse column
all 'a', 'b' & 'c'
sharp drop in pressure drop.
The entire amount of C is transferred to solvent B.
1.2 to 1.5
wet bulb temperature
dilute solutions and isothermal operation.
surface renewal
dilute solution and isothermal operation.
0.6
humidified with wet bulb temperature decreasing.
linear
momentum diffusivity to the mass dif-fusivity.
f = 1
repeated coalescence & redispersion of the drop phase.
interface
Reynolds number in mass transfer is analogous to Grashoff number in heat transfer.
-ve
gas side
0.5
continuous
12
The capacity of a distillation coloumn is maximum at total reflux.
Vapor phase obeys Dalton's law and liquid phase obeys Raoult's law.
less than
Sc / Pr
Pachuka tank
Pulsed column
equilibrium
unbound
isotopes of uranium
is computed from the slope of the upper operating line that is tangent to the equilibrium curve.
500
lower than
mass transfer co-efficient
In case of a stripper, the equilibrium curve is always below the operating line.
no separation will occur.
cylinder
Both (b) and (c)
Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature.
percolation
avoid channeling.
a pure substance
95
Co-efficient = Flux/concentration difference.
the relative humidity decreases.
equal to the heat of wetting.
1.25 to 2.0
The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity.
petroleum refinning
thermal decomposition of bottoms.
azeotropic
tray
Butyl acetate
sticky
partial pressure
gas
Temperature of the solid
always lower than
bound
high reflux ratio
both (a) & (b)
both (a) & (b).
spray dryer
liquid film
increasing the gas film co-efficient.
low tray efficiency
water has a high latent heat of evaporation.
driving force for the vapor flow is the pressure drop, as the pressure decreases gradually from the bottom to the top of the column.
Humidification
30
form a low boiling azeotrope with one of the constituents of the mixture.
mixing of steam with the material being vaporised is not so intimate as to result in equilibrium condition.
The operating pressure in solvent extraction system should be below vapor pressures of all components.
bubble the gas through liquid.
adsorption
the top and bottom compositions correspond to the maximum enrichment available.
conveyor
changes the relative volatility of the original components.
solid dispersed in gas
Bone charcoal
total
Dry bulb temperature
both heat and mass
sublimation
Froude number
water from petrol
Never
perfectly dry
minimum
increases with temperature.
> 25
partial pressure of a component over a solution is proportional to its mole fraction in the liquid.
dilute ammoniacal liquor
Decolouration of yellow glycerene.
beginning of falling
Relative saturation of unsaturated mixture of water vapor & air can not be increased by either reducing the mixture temperature or by increasing the total pressure.
2.0
Lewis reltionship
induced draft
baffle
Wetted wall columns
more than the wet bulb
Both heating and humidification
film
decreases with increase in
use of increased tray spacing.
differential
separation of a binary mixture by distillation.
Selectivity
log P vs . T
pure component is represented by the apex.
wet-bulb
10
thermal condition of the feed
product must be immiscible with water.
moving bed adsorption
leaching.
same as liquid composition.
thermal diffusivity to mass diffusivity.
D
at its boiling point
have very wide boiling points.
perfectly mixed
0.25
high pressure drop
Wetted wall tower
The mixture exhibits an azeotrope at 101.3 kPa.
and dehumidified with decrease in wet bulb temperature.
elution
Removing nicotine from its water solution by kerosene.
liquid extraction
synthetic zeolites crystals/metal alumino-silicates.
extractive distillation
there is equimolar counter diffusion.
distillation column
no
neither (a) nor (b).
long tube
plug
leaching
McCabe-Thiele method
Fine solids can not be leached in a Pachuka tank.
100
uses molal units for material and energy balance.
Toor and Marchello
1.25 to 2
in towers packed with stacked packing.
more readily done in the second case compared to first one.
crystallisation.
fluid-solid
extractive
thermal diffusio
oxidising atmosphere
0.2
both (b) and (c).
is characterised by the presence of foam throughout the space between trays.
carbon dioxide.
Murphree efficiency = point efficiency.
vapour is in equilibrium with the liquid at the gas temperature.
The operating line lies above the equilibrium curve in case of a gas desorber.
18.7
None of these.
driving force for the liquid flow is its weight.
tunnel
3
partial pressure of vapour in the mixture.
used for multicomponent systems like crude refining.
Higbie
high operating cost.
component molecules are nonpolar.
vacuum
centrifugal
1/P
pure gas
Schmidt
Stanton number
gas absorption with chemical reaction.
infinite trays and minimum reboiler heat load.
heated charcoal
increases in winter
hold up large amount of liquid in the packing.
Monoethanol amine (MEA)
9
< 1 and ≈ 1
II, III
thermal energy of the molecules.
solubility
simple
Diameter of randomly packed tower is normally more than 1.2 metres.
are different
decreasing pressure
Bamboo
truck/tunnel.
differential distillation equation
large quantity of solvent is required to extract the solute.
4.605
and equilibrium lines are parallel.
Both condensor and reboiler loads are higher in case (ii) as compared to case (i).
binary phase distillation
slightly concave upward.
Zirconia probe is used for the humidity measurement.
the water entrained by the circulating air.
packed column
0.152
at < 100
Vanderwall adsorption is also called chemisorption.
high labour cost & low heat economy.
> 8:1
Bubble
Danckwerts
temperature rises
temperature rises.
gm moles/cm. sec
cold water leaving the tower and the wet bulb temperature of the surrounding air.
a counter diffusion at an almost equal molar rate
both gas as well as liquid streams should be distributed uniformly.
ultrafiltration.
Fluidised bed drier
azeotropic mixture is to be separated and the final product is miscible with water.
porosity
Reverse osmosis
Packed tower
known
liquid is enriched with high boiler.
Kg
Freundlich equation
employs two solvents
at ground level.
alkalis
ethanolamine
does not change with time,
Mass transfer co-efficient does not account for gase-liquid diffusion.
vapour is enriched with high boilers.
f/2
1.24
maximum condenser size.
increase in pressure drop.
mole ratio
an azeotrope may be formed during distillation.
is a function of the mass transfer between liquid and vapour.
decrease in equilibrium solubility.
high pressure drop of the gas.
number of plates required will be maximum.
having very wide boiling points.
both the operating lines coincide with the diagram.
small sizes.
Molecular diffusion in solid is much faster than that in liquids.
Winkel mann's
tangential to the equilibrium curve
humidified
liquid side coefficient should be increased.
10-15
differential heat of adsorption.
rotating disc extractor
increased utilisation of stagnant zones of the liquid phase.
temperature decreases.
acetone chloroform
0.1
Agitated film evaporator
decrease
inside
8.89
of the assumption that vapour and liquid leaving the reboiler are in equilibrium.
Last changed9 months ago