PARTICLE TECHNOLOGY

Question 1

In operating a batch filter, which of the following is the correct method of operation?

A. The particles forming the cake should be large.
B. The slower the flowrate, the more efficient the recovery.
C. Keeping the pressure constant, the rate of flow increases.
D. Keeping the flowrate constant and gradually increase the pressure.

Answer 1

Keeping the flowrate constant and gradually increase the pressure.

Question 2

Relation of 1/k and 2Ve/k to A

Answer 2

1/k is directly proportional to the 1/A^2
2Ve/k is directly proportional to 1/A

Question 3

Relationship of 1/k and 2Ve/k to delta P

Answer 3

1/k is directly proportional to the 1/delta P
2Ve/k is directly proportional to 1/delta P

Question 4

This is used as a precoat on the filter media or mixed to the slurry to increase the porosity of the cake.

Answer 4

Filter aids

Question 5

Examples of filter aids

Answer 5

diatomaceous silica
perlite
purified wood cellulose

Question 6

Batch filtration vs Continuous filtration

Answer 6

Batch-small capacity (PFFP,LEAF)
CONTINUOUS- LARGE CAPACITY (CONTINUOUS ROTARY FILTER)

Question 7

Driving force of filtration

Answer 7

gravity, pressure/vacuum

Question 8

The porosity of compressible cake is
a. minimum at the filter medium
b. minimum at the upstream face
c. maximum at the filter medium
d. same throughout the thickness

Answer 8

a. minimum at the filter medium

Question 9

It is the barrier that lets the liquid pass while retaining most of the solids

Answer 9

filter medium or septum

Question 10

T OR F
Increase in feed solids concentrationis generally an effective means of increasing solids filtration rate, and thereby minimizing cake moisture content.

Answer 10

T

Question 11

These chemicals are used for pretreatment of slurries to provide acceptable filtration rate.

Answer 11

Flocculating agent

Question 12

Random motion imparted to the partile by collisions between molecules of the fluid surrounding the particle.

Answer 12

Brownian motion

Question 13

Devices used for the separation of solids particles into several fractions based on their rate of settling through a medium

Answer 13

Classifiers

Question 14

Devices used for the separation of solids particles into several fractions based on their settling velocity in a medium

Answer 14

Classification

Question 15

The operation by which solids are separated from liquids due to difference in the respective densities

Answer 15

sedimentation

Question 16

forces acting on a particle in fluid are

Answer 16

external force, buoyant force, drag force

Question 17

It is defined as the force exerted by the fluid on a particle in the opposite to the direction of flow of the particle

Answer 17

drag force

Question 18

the terminal velocity of a small sphere settling in a viscous fluid varies as the
a. first power of its diameter
b. inverse of the fluid viscosity
c. inverse square of the diameter
d. square of the difference in specific weights of solid and fluid

Answer 18

b. inverse of the fluid viscosity

Question 19

buoyant force
a. for non-symmetrical bodies is not vertical
b. a fluctuating velocity
c. depends on the weight of the floating body
d. none of these

Answer 19

c. depends on the weight of the floating body

Question 20

terminal velocity is
a. constant velocity with a=0
b. a fluctuating velocity
c. attained after moving one-hald of total distance
d. none of these

Answer 20

a. constant velocity with a=0

Question 21

in hindered settlinb, particles are

Answer 21

near each other

Question 22

moisture can be removed from lubricating oil using
a. tubular centrifuge
b. clarifier
c. sparkle filter
d. vacuum leaf filter

Answer 22

a. tubular centrifuge

Question 23

milk cream separator
a. disc bond centrifuge
b. sharpless supercentrifuge
c. batch basket centrifuge
d. sparkler filter

Answer 23

a. disc bond centrifuge

Question 24

most effectively used for clarification of lube oil and printing ink

a. sparkler filter
b. precoat filter
c. disc bowl centrifuge
d. sharpless supercentrifuge

Answer 24

d. sharpless supercentrifuge

Question 25

It is used to grind wheat and rye to flour and corn

Answer 25

roller mills

Question 26

Used to produce potator flour, tapioca and other flours

Answer 26

hammer mills

Question 27

It is mainly used for crushing hard materials and are usually followed by other crushers

Answer 27

jaw crusher

Question 28

is the temperature attained when large amount of water is contacted with the entering gas

Answer 28

adiabatic saturation tempetrature

Question 29

what is adiabatic saturation line?

Answer 29

adiabatic humidification line

Question 30

Steady state temperature reached by a small amount of liquid evaporating into large amount of unsaturated vapor gas mixture

Answer 30

Wet bulb