Mass transfer co-efficient (K) and diffusivity (D) are related according to film theory as
An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored; (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii)
With increase in temperature, the solubility of gases in liquids, at fixed pressure
The binary diffusivity in gases at atmospheric conditions is about
Bollman extractor
Pick out the wrong statement.
When the temperature and humidity of air is low, we usually use __________ draft cooling tower.
At minimum reflux ratio for a given separation
In case of an absorber, the operating
Which of the following is the most suitable for extraction in a system having very low density difference ?
Pick out the correct statement.
The partial pressure distribution of an ideal gas diffusing through another stagnant ideal gas at steady state follows a/an __________ law.
In most of the vacuum crystalliser, vacuum is generally produced by means of a
Percentage saturation is __________ the relative saturation.
The relation, Sc = Pr =is valid, when the mechanism of __________ ansfer is same.
As complete saturation of an adsorbent is approached, the differential heat of adsrop-tion approaches
For achieving rapid drying rate in a spray dryer, the diameter of the particles in the feed should be in the range of __________ microns (1 mm =microns).
A good solvent used for absorption should not have very high
Pick out the wrong statement pertaining to the rotary dryer.
Positive deviation from Raoult's law means a mixture whose total pressure is
In case of a desorber (stripper), the
Absorption factor method is used to calculate the number of ideal stages, when
Pick out the wrong statement.
A minimum boiling azeotrope is exemplified by
A coalescer in a mixer-settler liquid-liquid extraction coloumn
At equilibrium the concentration of water in vapour phase (C*)in kg/m3 of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by, C* = 0.0667m. To maintain dry conditions in a room of air space 100m3 containing 2.2 kg of water vapour initially,kg of dry silica gel is kept in the room. The fraction of initial water remaining in the air space after a long time (during which the temperature is maintained constant) is
'Absorption with chemical reaction' is involved in the removal of
For absorbing a sparingly soluble gas in a liquid
In a counter-current liquid extractor
With increase in gas rate, the number of transfer units, NtoG, for a fixed degree of absorption by a fixed amount of solvent
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
What is the reflux ratio at total reflux ?
Flights in a rotary dryer are provided to
Only small amount of evaporation of water produces large cooling effects because of its
Hydrogenation of oil is carried out in a/an __________ in Vanaspati manufacturing plant.
Which of the following solutions will follow Raoult's law most closely ?
The apex of an equilateral-triangular coordinate (in ternary liquid system) represents a/an
For the same feed, feed quality and separation (in a distillation column), with the increase of total pressure, the number of ideal plates will
Dry bulb temperature of unsaturated air is more than its __________ temperature.
The-relative volatility for separation of a non-ideal binary mixture by distillation should be
Channelling in a packed tower results from the
Which of the following is an undesirable property for an absorbing solvent ?
The caking of crystals can be prevented by
__________ column is the most suitable for achieving the best performance for mass transfer operations involving liquid with dispersed solids.
Deairation (removal of O2) of water is done by
Under conditions of flooding in packed tower, the gas pressure drop
The Kundsen diffusivity is proportional to (where, T = absolute temperature)
Which of the following is an undesirable property in a tower packing ?
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
The most common packing used in industrial operations is __________ rings.