HeMaTra

Question 1

Evaporation is also sometimes called as
a. thermal compression c. water distillation
b. liquid compression d. vapor compression

Answer 1

c. water distillation

Question 2

The concentration of glycerin from a water solution by the application of heat is
a. distillation c. crystallization
b. evaporation d. reverse osmosis

Answer 2

b. evaporation

Question 3

The total amount of evaporation an evaporator is capable of producing per unit of time.
a. economy c. steam consumption
b. capacity d. fouling factors

Answer 3

b. capacity

Question 4

When the pressure of the chamber is decreased, the boiling point of the solution inside the chamber will
a. increase c. decrease
b. remain the same d. increase or decrease

Answer 4

c. decrease

Question 5

A heat transfer device that is normally used to liquefy vapors is
a. evaporator c. reboiler
b. condenser d. humidifier

Answer 5

b. condenser

Question 6

The temperature driving force in an evaporator is determined as the difference between the condensing steam temperature and
a. condenser temperature b. boiling point of the solution
c. boiling point of the solvent d. BPR of the solution

Answer 6

b. boiling point of the solution

Question 7

In a country where capital is scarce and energy cost is low, which is appropriate to install?
a. multiple effect evaporator b. single effect evaporator

Answer 7

b. single effect evaporator

Question 8

The fresh feed enters at the coldest effect.
a. feed-forward c. feed-backward
b. parallel-feed d. none of these

Answer 8

c. feed-backward

Question 9

In commercial practice, the areas in all effects for a multiple effect evaporator are
a. greater c. lesser
b. constant d. equal

Answer 9

d. equal

Question 10

A multiple effect evaporator ______the steam cost
a. increases c. decreases
b. keep the same d. double

Answer 10

c. decreases

Question 11

___ of the vapor is recovered and reuse in the multiple effect evaporator.
a. heat transfer c. specific heat
b. latent heat d. sensible heat

Answer 11

b. latent heat

Question 12

It is the deposition and growth on body walls, and specially on heating surfaces, of a material undergoing an irreversible chemical reaction in the evaporator.
a. salting c. scaling
b. fouling d. boiling

Answer 12

c. scaling

Question 13

It is the formation of deposits other than salt or scale and maybe due to corrosion.
a. salting c. scaling
b. fouling d. boiling

Answer 13

b. fouling

Question 14

In industrial crystallization from a solution, the two phase mixture of mother liquor and crystals of all sizes, which occupies the crystallizer and is withdrawn as product is called
a. product crystals c. mother liquor
b. magma d. invariant crystals

Answer 14

b. magma

Question 15

In practice, slow cooling maintaining a low level of supersaturation produces ___ crystals and fast cooling produces ___ crystals.

Answer 15

large, small

Question 16

It is the process by which crystalline bodies are created within a supersaturated fluid.
a. polymorphism c. nucleation
b. crystal growth d. seeding

Answer 16

c. nucleation

Question 17

When a solution is cooled to produce a supersaturated solution and hence to cause crystallization, the heat that must be removed is the sum of the ____ necessary to cool the solution and the heat of crystallization.
a. heat of reaction c. enthalpy
b. sensible heat content d. heat of condensation

Answer 17

b. sensible heat content

Question 18

To remove all the moisture from a wet solid requires exposure to
a. perfectly dry air c. highly humid air
b. air at high temperature d. none of these

Answer 18

a. perfectly dry air

Question 19

The portion of water in the wet solid that cannot be removed by the air in its contact is called
a. free moisture b. final moisture content
c. equilibrium moisture content d. critical moisture content

Answer 19

c. equilibrium moisture content

Question 20

Moisture contained by a substance in excess of the equilibrium moisture is called
a. unbound moisture c. free moisture
b. critical moisture d. bound moisture

Answer 20

c. free moisture

Question 21

When drying banana chips under the sun, the rate of drying is faster on a
a. slightly breezy day c. calm day
b. cloudy day d. hot and windy day

Answer 21

d. hot and windy day

Question 22

The critical moisture content in case of drying indicates
a. beginning of falling rate period b. beginning of constant rate period
c. end of falling rate period d. none of these

Answer 22

a. beginning of falling rate period

Question 23

In drying at the falling rate period, the rate at which moisture is removed from the solid material
a. increases with time b. remains constant c. decreases with time d. no more drying takes place

Answer 23

c. decreases with time

Question 24

Heat sensitive materials like certain pharmaceuticals and food stuff can be dried
a. in indirect tray dryer c. in spray dryer
b. by freeze drying d. festoon dryer

Answer 24

b. by freeze drying

Question 25

Detergent solution is dried to a powder in a
a. spray dryer c. spouted bed dryer
b. tunnel dryer d. pan open to atmosphere

Answer 25

a. spray dryer

Question 26

Calcium ammonium nitrate (a fertilizer) is dried in a
a. rotary dryer c. vacuum dryer b. tunnel dryer d. none of these

Answer 26

a. rotary dryer

Question 27

Rotary dryer cannot handle
a. free flowing materials c. dry materials
b. sticky materials d. granular materials

Answer 27

b. sticky materials

Question 28

It involves the removal of moisture, usually water from a solid by allowing the composite material to come into contact with a drying medium that supplies the head needed by the moisture to evaporate.

Answer 28

Drying

Question 29

Highest humidity

Answer 29

Saturated Humidity

Question 30

Equilibrium pressure at bubble point and dew point

Answer 30

Vapor Pressure

Question 31

Process whereby a solution becomes supersaturated so as to cause the formation of crystals

Answer 31

CRYSTALLIZATION