Separation of Particle from Solid-Gases

Question 1

What is a PRIMARY purpose of gas-solid separation?

Answer 1

To improve air quality

Question 2

Dust particles are typically larger than what size?

Answer 2

10 micrometers

Question 3

What property of a particle is MOST important for gas-solid separation using simple
methods?

Answer 3

Size

Question 4

What is the main resistance to motion for particles smaller than 100 micrometers in a gas
stream?

Answer 4

Viscosity

Question 5

What is the unit typically used for particle size in gas-solid separation?

Answer 5

Micrometers

Question 6

In gas permeation membranes, what is the main driving force for separation?

Answer 6

Pressure difference

Question 7

Flat membranes offer what advantage in gas permeation processes?

Answer 7

Ease of fabrication

Question 8

Which type of membrane has the highest membrane area per unit volume in gas permeation
processes?

Answer 8

Hollow fiber membranes

Question 9

In cross-flow models for gas separation by membranes, which stream is typically assumed
to be in plug flow?

Answer 9

Feed stream only

Question 10

In the complete-mixing model for gas separation by membranes, what is a limitation?

Answer 10

It is not accurate for high recovery processes.

Question 11

In gas-solid separation, what can be recovered as a valuable product in dry state?

Answer 11

Powdered catalyst

Question 12

What is the relationship between aerodynamic diameter and the settling velocity of a
particle?

Answer 12

They are directly proportional.

Question 13

In gas permeation, what is the effect of temperature on permeability generally?

Answer 13

Permeability decreases significantly.

Question 14

What is the main advantage of using complete-mixing models for gas separation by
membranes?

Answer 14

They are simpler to calculate compared to other models

Question 15

Gas permeation membranes rely on a _____ as the driving force for separation

Answer 15

pressure difference

Question 16

In a cyclone separator, the _____ force acts on a particle in the outward radial direction.

Answer 16

centrifugal

Question 17

Early gas permeation membranes were limited by their low _____ .

Answer 17

permeability

Question 18

The ideal separation factor (α) in gas permeation represents the ratio of the _____ of two
components in the mixture.

Answer 18

permeabilities

Question 19

The _____ of a gravity settling chamber is determined by the particle trajectory within
the unit.

Answer 19

efficiency

Question 20

(A) Gas-solid separation processes are always used to improve air quality. (B)The size of
a particle is the only factor affecting its settling velocity in a gas stream

Answer 20

Both statement A and B are False

Explanation (A) -While improving air quality is a common application, gas-solid separation
can also be used to recover valuable products or remove harmful pollutants from process
streams in various industries.

Explanation (B) - Particle size is a crucial factor, but other factors like particle density, shape,
and the gas viscosity also influence settling velocity

Question 21

The separation of solid particles from a suspension consists of fine particles of different
materials in water using a flotation technique depends upon the differences in the

Answer 21

surface properties of the solid particles being used

Question 22

Theoretical cut particle size for a gas cyclone is

Answer 22

The theoretical size of the standard

Question 23

Which of the three phases of matter (solid, liquid, or gas) has particles separated by the
least amount of distance?

Answer 23

solid

Question 24

The accurate prediction of permeabilities of gases in membranes is generally not possible, and experimental values are needed.

Answer 24

Permeability of membranes

Question 25

The grade efficiency of gravity settling chambers can be calculated based on particle trajectory within the unit. The best-established models of collector performance are those for fibrous filters and fixed-bed granular filters, in which the structures and fluid-flow patterns are reasonably well defined.

Answer 25

Only the first statement is true

Question 26

Inertial separators in which particles are separated from the gas by inertial impingement collecting bodies arrayed across the path of the gas stream.

Answer 26

Impingement Separators

Question 27

It is a performance of a gas-solids separation device is most commonly expressed as the ______ n, the weight ratio of the dust collected to the dust entering the apparatus.

Answer 27

Collection efficiency

Question 28

The feed enters the cyclone _____ near the top and is given a spinning motion as it enters the _____.

Answer 28

Tangentially, chamber proper

Question 29

Which of the following applications of cyclones is not found in industries involved with fluid-particles processing?

Answer 29

Pharmaceutical

Question 30

It is in the opposite direction to the particle’s centrifugal force because it is on a volume of fluid that is missing compared to the surrounding fluid.

Answer 30

buoyant force

Question 31

In a conventional reverse-flow cyclone, the _________ usually enters a cylindrical or conical chamber tangentially at one or more entrances (usually rectangular in cross section) and leaves through a central opening

Answer 31

dust-laden gas

Question 32

In deriving theoretical models for gas separation by membranes, isothermal conditions and negligible pressure drop in the feed steam and permeate stream are _______

Answer 32

generally assumed

Question 33

At what percent efficiency is it possible for a coarse dust to be collected wherein a fine dust may be separated with lower efficiency in the _____ operating at exactly the same conditions?

Answer 33

100% efficiency , same unit

Question 34

Gravity collectors are generally built in the form of long, empty, horizontal, rectangular chambers with an inlet at one end and an outlet at the side or top of the other end.

Answer 34

Inlet , Outlet

Question 35

What are the two types of solid dispersed in gases?

Answer 35

Fume and Dust

Question 36

For preliminary selection, the analytical cut diameter can be estimated from the particle-size distribution of the incoming dust

Answer 36

Particle-size distribution

Question 37

Very fine particles tend to agglomerate into a loose,_______ whereas coarse particles may be nonporous and dense

Answer 37

Porous structure

Question 38

It plays an important role in its ability to be entrained and remained in suspension.

Answer 38

Particle Density

Question 39

In a reverse flow cyclones, the gas moves in a double vortex with a gas initially spiraling downward at the outside after it enters the inlet,, the flowing upward in the center of cyclones before it exist

Answer 39

flow pattern

Question 40

For any separators device, the relative contribution of various collection mechanism depends on what characteristics

Answer 40

Particle and gas characteristics

Question 41

Devices that particles are separated from a dust-laden stream when the direction pf gas flow is line but continue to be concentrated in the dust stream

Answer 41

Louver and Baffle Collectors

Question 42

In a type of permeates it says (A)In a membrane process high-pressure feed pas is supplied to one side of the membrane and permeates normal to the membrane.(B) The permeate leaves in a direction normal to the membrane, accumulating on the low-pressure side

Answer 42

The both statement is true

Question 43

The particle size on a cumulative weight percent oversize distribution curve that is numerica the _______

Answer 43

desired overall collection efficiency of the gas-solid separation device.

Question 44

The ________ measurement is one of the common methods for obtaining a relative long-period evaluation of particulate air pollution

Answer 44

dust-fall

Question 45

Dusts usually result from mechanical disintegration of matter. Fuse are submicrometer dispersed solids formed by processes such as combustion, sublimation, and distillation.

Answer 45

Only the first statement is true

Question 46

Due to______, the particles do not follow the gas streamlines but continue to be concentrated in the dust stream.

Answer 46

Inertia

Question 47

The tangential entry of gas creates a swirling flow within the cyclone body that imparts a substantial centrifugal separating force on the particles

Answer 47

Imparts

Question 48

When a separator element is operated at low recovery, there is a minimal change in ______

Answer 48

Composition

Question 49

Which of the following example given for Chemical in fluid-particle processing is not included?

Answer 49

Distillating

Question 50

For the design of a system there are _____ variables in the complete-mixing model

Answer 50

seven