Mass Transfer (Set 2) Flashcards
As one of the transport phenomena, the concepts in mass transfer are crucial for design, operation, and maintenance of mass or heat & mass transfer equipment such as mixing and separation processes.
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
increased reflux ratio
____ column is the most suitable for achieving the best performance for mass transfer operations involving liquid with dispersed solids.
Plate
Deairation (removal of O2) of water is done by
ion-exchange
Make up water is supplied during cooling tower operation to compensate for water losses due to
all (a), (b) & (c)
evaporation, blowdown & entrainment
Pick out the wrong statement.
Azeotropes obey Raoult’s law at all temperature.
A minimum boiling azeotrope is exemplified by
acetone-carbon disulphide
Which of the following solutions will follow Raoult’s law most closely?
A solution of benzene, toluene and oxylene.
Use of raschig rings in place of crushed stones as packing in packed beds (other things being same)
decreases pressure drop, increases surface area.
Critical humidity of a solid salt means the humidity
both (a) and (b).
The assumption made in Elis method in distillation is that enthalpy concentration lines of vapor and liquid are
both parallel and straight
As complete saturation of an adsorbent is approached, the differential heat of adsrop-tion approaches
that of normal condensation.
Absorption with chemical reaction’ is involved in the removal of
carbon dioxide from gaseous stream using alkaline solution.
The-relative volatility for separation of a non-ideal binary mixture by distillation should be
> 1
Pick out the wrong statement:
Fenske-Underwood equation is used for calculating theoretical number of plates in a distillation column at normal operating reflux condition.
In paper industry, paper is dried in a ____ dryer.
heated cylinder
Pick out the wrong statement.
Dehydration of ethyl alcohol is most economically done by molecular distillation at very high vacuum.
Only small amount of evaporation of water produces large cooling effects because of its
large latent heat
The most common packing used in industrial operations is ____ rings.
raschig
When the feed to a distillation column is a saturated liquid, slope of the feed line is
infinity
Leaching of sugar from sugar beets is done by
hot water
Absorption factor method is used to calculate the number of ideal stages, when
both operating and equilibrium lines are parallel.
Flights in a rotary dryer are provided to
lift and shower the solids thus exposing it thoroughly to the drying action of the gas.
If f = moles of vapour present per mole of feed, then the slope of feed line is (Mcabe-Thiele method)
-1/f
If the solubilities of different components (in a liquid-liquid extraction system) increase with rise in temperature, then the temperature above which they dissolve completely is known as the critical solution temperature (CST or consolute temperature). If solubilities increase with decrease in temperature, then CST is the temperature below which they dissolve completely. If a binary system has no critical solution temperature, it implies that
on heating, a vapor phase will appear ; while on cooling, a solid phase will appear.