Solid and Liquid Pollutants

Question 1

Mechanical centrifugal collectors remove particulate by means
of
a) centrifugal force
b) inertia
c) gravitational force
d) all of the above
e) none of the above

Answer 1

d) all of the above

Question 2

Mechanical centrifugal collectors are not suitable for the
collection of
a) very coarse particles
b) coarse particles
c) fine particles
d) rough particles
e) heavy particles

Answer 2

c) fine particles

Question 3

Wet scrubbers remove

a) gases only
b) gases and dust only
c) particulates only
d) acidic gases only
e) dust only

Answer 3

b) gases and dust only

Question 4

In an electrostatic precipitator the
a) discharge electrode is negatively charged
b) collector electrode is negatively charged
c) discharge electrode is positively charged
d) particles are positively charged
e) discharge electrode and the particles are positively
charged

Answer 4

a) discharge electrode is negatively charged

Question 5

The voltage supplied to an electrostatic precipitator is
between
a) 10,000 volts AC and 1,000,000 volts AC
b) 10,000 volts DC and 100,000 volts DC
c) 1,000,000 volts AC and 1,000,000,000 volts AC
d) 100,000 DC and 1,000,000,000 volts AC
e) 100,000 AC and 10,000 volts DC

Answer 5

b) 10,000 volts DC and 100,000 volts DC

Question 6

When ground level sulphur dioxide concentrations are
increasing above allowable limits, the operators choice of
action to reduce the sulphur dioxide emissions includes:
1. reduce boiler load
2. increase the voltage level on the electrostatic
precipitators to remove more sulphur dioxide
3. increase the boiler load to disperse the sulphur
dioxide over a wider area
4. switch to a low sulphur fuel
5. shut down the boilers
a) 1, 3, 4
b) 2, 3, 5
c) 1, 4, 5
d) 1, 4
e) 3, 4, 5

Answer 6

c) 1, 4, 5

Question 7

Some areas of a power plant are difficult or not economically
suitable to provide a pollution free area in which employees
can work in. These types of areas are:
1. control rooms
2. coal conveyor galleries
3. cleaning ash hoppers or precipitators internally during
a boiler repair
4. lunch rooms
5. coal crushing and grinding equipment
6. steam turbine bays
a) 2, 3, 5, 6
b) 1, 2, 3, 5
c) 2, 3, 4, 5
d) 1, 3, 6
e) 3, 4, 6

Answer 7

a) 2, 3, 5, 6

Question 8

Fly ash is removed from bag filters by a system of

a) rollers
b) hammers
c) electrostatic precipitators
d) shakers
e) rappers

Answer 8

e) rappers

Question 9

Fly ash is normally less than

a) 1 mm in diameter
b) 0.3 mm in diameter
c) 1,000 microns in diameter
d) 300 microns in diameter
e) 30 microns in diameter

Answer 9

e) 30 microns in diameter

Question 10

Fly ash collected by pollution control devices can be used in
the
a) petroleum industry
b) electrical industry
c) tire industry
d) construction industry
e) landscaping industry

Answer 10

d) construction industry

Question 11

Solid pollutants such as flyash are produced when burning:

1. natural gas
2. heavy fuel oil
3. wood
4. coal
   a) 1, 4
   b) 2, 3, 4
   c) 1, 2, 3
   d) 3, 4
   e) 1, 2, 3, 4

Answer 11

b) 2, 3, 4

Question 12

Solid pollutants emitted from power plants are:

1. dust
2. soot
3. flyash
4. carbon monoxide
5. sulphur dioxide
6. sulphuric acid
   a) all of the above
   b) 2, 3, 6
   c) 1, 2, 3, 6
   d) 2, 4, 5
   e) 1, 2, 3

Answer 12

e) 1, 2, 3

Question 13

Liquid pollutants emitted from power plants include:

1. water at elevated temperatures
2. waste water from flue gas scrubbing
3. waste water from water treatment processes
4. waste water from ash handling operations
   a) 1, 4
   b) 1, 3, 4
   c) 1, 2, 3, 4
   d) 2, 3, 4
   e) 2, 4

Answer 13

c) 1, 2, 3, 4

Question 14

"The amount of any gas that water can dissolve depends on the
partial pressure the gas exerts on the free surface of the
water", is stated by
a) Henry's Law
b) Boyles's Law
c) Charles' Law
d) Dalton's Law
e) The General Gas Law

Answer 14

a) Henry’s Law

Question 15

Natural draft cooling towers are divided into

a) dry and wet types
b) closed and semi-closed types
c) open and closed types
d) filled and unfilled types
e) open and filled types

Answer 15

c) open and closed types

Question 16

The most common type of mechanical draft cooling tower is

a) a forced draft type
b) an induced draft type
c) a wet type
d) a dry type
e) a combination wet and dry type

Answer 16

b) an induced draft type

Question 17

Air flow in a natural draft cooling tower is dependent upon
the
a) speed of the cooling fan
b) volume of water flowing through
c) partial pressure exerted above the surface of the
reservoir
d) differences in densities of the air leaving and entering
e) wind direction

Answer 17

d) differences in densities of the air leaving and entering

Question 18

Advantages of ID cooling towers over FC cooling towers
include:
1. accessibility of the fan for maintenance
2. little chance of icing up in winter
3. minimum noise
4. a greater ability to cool the water
5. ability to recycle the vapour laden air
a) 1, 3, 5
b) 3, 4, 5
c) 2, 3, 4
d) 1, 2, 3
e) 2, 3, 5

Answer 18

c) 2, 3, 4

Question 19

Cooling towers

a) need only be operated in the summer months
b) may contribute to the pollution problem
c) remove heat from the condensate
d) require fans
e) do not require any maintenance

Answer 19

b) may contribute to the pollution problem

Question 20

Dry cooling towers
a) operate by natural draft
b) have the cooling water flow from bottom to top
c) have an ID fan located at the top
d) have an FD fan located at the bottom
e) pass the cooling water through a closed circuit of finned
tubes

Answer 20

e) pass the cooling water through a closed circuit of finned

tubes