Engineering :: Environmental Engineering

@ : Home > Chemical Engineering > Environmental Engineering

21.

The operation of a cyclone separator relies on

A.	centrifugal force acting on the particle	B.	producing an electric charge on the particle to be collected and then directing it by electrostatic forces to the collecting electrodes
C.	the creation of intimate contact between a stream of gas and a flow of scrubbing liquor	D.	diffusion of dust particles

22.

The collection efficiency of a cyclone separator

A.	is directly proportional to the mass of the dust particle	B.	is inversely proportional to the radius of the dust particle path
C.	increases with increase in gas flow rate	D.	all of the above

23.

For a given particle size the collection efficiency of a cyclone separator

A.	will be increased at higher pressure drops	B.	will be decreased at higher pressure drops
C.	will not be affected by changing pressure drop	D.	none of the above

24.

In an aerosol

A.	some of the particles may be positively charged	B.	some of the particles may be negatively charged
C.	some of the particles may be uncharged	D.	all of the above

25.

High absolute humidity

A.	increases the explosibility of the aerosol	B.	decreases the explosibility of the aerosol
C.	does not change the explosibility of the aerosol

26.

The operation of electrostatic precipitator relies on

A.	producing an electric charge on the particle to be collected and then directing it by electrostatic forces to the collecting electrodes	B.	centrifugal force acting on the particle
C.	diffusion of dust particles	D.	the creation of intimate contact between a stream of gas and a flow of scrubbing liquor.

27.

The operating pressure drop for the electrostatic precipitator including perforated plates varies in the range of

A.	0.2 to 0.5 in. H2O g	B.	3 to 60 in. H2O g
C.	2 to 6 in. H2O g	D.	0.01 to 0.1 in. H2O g

28.

In the electrostatic precipitator

A.	high conductivity material is more easily collected	B.	low conductivity material is more easily collected
C.	electrical conductivity of material is not an important factor	D.	none of the above

29.

The electrostatic precipitators have an efficiency characteristic which is related primarily to exposure time i.e. the period during which a dust particle is exposed to the electrostatic field. Exposure time can be increased by

A.	increasing the cross-sectional area of the precipitator	B.	increasing its length in the direction of gas flow
C.	both a and b	D.	neither a nor b

30.

The collection efficiency of electrostatic precipitator depends on

A.	the electrode area	B.	the particle drift velocity
C.	the gas flow rate	D.	all of the above