Gaseous and Noise Pollutants

Question 1

Sulphur oxides in flue gas are undesirable because
a) they use up the sulphur in the fuel
b) they cause acid rain
c) they reduce combustion efficiency
d) they combine with sunlight to produce smog
e) they are an indicator of incomplete combustion in the
furnace

Answer 1

b) they cause acid rain

Question 2

Carbon monoxide is produced as a result of

a) a shortage of oxygen in the furnace
b) too high a combustion temperature
c) too large a furnace
d) excess air in the combustion process
e) slow movement of fuel through the furnace

Answer 2

a) a shortage of oxygen in the furnace

Question 3

Gaseous pollutants emitted from power plants are:

1. natural gas
2. oxygen
3. carbon monoxide
4. sulphur dioxide
5. nitrogen
   a) 1, 3, 4
   b) 2, 3, 4
   c) 3, 4, 5
   d) 3, 4
   e) 1, 2, 5

Answer 3

d) 3, 4

Question 4

Most systems used today to remove sulphur dioxide

a) produce a useful end product
b) remove most of the sulphur trioxide as well
c) involve the use of lime, limestone or sulphuric acid
d) remove the sulphur dioxide in the furnace
e) are simple systems involving little extra equipment

Answer 4

c) involve the use of lime, limestone or sulphuric acid

Question 5

Nitrogen oxides in flue gas may be reduced by

a) raising the furnace temperature
b) decreasing the size of the furnace
c) scrubbing the flue gas with lime
d) reducing the percentage of excess air
e) employing a dilute sulphuric acid scrubber system

Answer 5

d) reducing the percentage of excess air

Question 6

Converting carbon monoxide to carbon dioxide in the furnace
may be accomplished by
1. increasing the amount of combustion air
2. decreasing the time the fuel spends in the furnace
3. burning lime with the fuel
4. not overloading the boiler
5. ensuring a good fuel/air mixture
a) 1, 4, 5
b) 2, 3, 4
c) 3, 4, 5
d) 1, 2, 4
e) 2, 4, 5

Answer 6

a) 1, 4, 5

Question 7

Systems designed to reduce SO are also effective in reducing
2
the concentration of
a) NO
x
b) H O
2
c) SO
3
d) CO
e) CO
2

Answer 7

c) SO

3

Question 8

A method proven to reduce emissions of sulphur oxides in the
flue gas is to
a) lower the furnace temperature
b) scrub the flue gas with wet lime or limestone
c) reduce the amount of excess air
d) use dilute sulphuric acid to scrub the flue gas
e) increase the size of the furnace

Answer 8

b) scrub the flue gas with wet lime or limestone

Question 9

A sampling and analyzing train

a) measures the frequency composition of noise
b) monitors flue gas for one type of emission
c) cannot be operated automatically
d) measures the amount of several types of emissions
e) cannot be used to obtain permanent records

Answer 9

d) measures the amount of several types of emissions

Question 10

A device for measuring flue gas emissions is called

a) a stack monitor
b) an Orsat analyzer
c) a stack analyzer
d) a level meter
e) a gas tester

Answer 10

b) an Orsat analyzer

Question 11

Choose all of the following statements which are true:

1) Sound travels through variations in air pressure
2) Sound waves are reflected, deflected ,and absorbed
3) Sound is a form of energy
4) Sound travels through a vacuum
5) Sound always travels at a constant wavelength
a) 1, 3, and 5
b) 1, 2, 3, and 4
c) 2, 3, 4, and 5
d) 2, 3, and 4
e) 1, 2, and 3

Answer 11

e) 1, 2, and 3

Question 12

Sound pressure level is expressed in

a) psi (pounds per square inch)
b) kPa
c) decibels
d) watts
e) amps

Answer 12

c) decibels

Question 13

Noise sources over what level are potentially hazardous to
hearing?
a) 100 dB and above
b) 60 dB and above
c) 120 dB and above
d) 80 dB and above
e) 40 dB and above

Answer 13

a) 100 dB and above

Question 14

Decibels are represented by

a) an exponential scale
b) an intensity scale
c) an arithmetic scale
d) a reference scale
e) a logarithmic scale

Answer 14

e) a logarithmic scale

Question 15

Noise pollution is caused by:

1. high speed equipment
2. popping high pressure safety valves
3. chimneys
4. jack hammers
5. riveting operations
   a) 1, 2, 3
   b) 1, 2, 4, 5
   c) 2, 3, 4, 5
   d) 1, 3, 4, 5
   e) 3, 4, 5

Answer 15

b) 1, 2, 4, 5

Question 16

Damaging sound pressure levels affecting plant personnel
could not be reduced by
a) enclosing the noise source
b) modifying the equipment operating conditions
c) building a barrier
d) wearing protective equipment
e) changing the frequency of the sound

Answer 16

e) changing the frequency of the sound

Question 17

Loud noises may be controlled by:

1. building soundproof cabinets around equipment
2. running the equipment at high speeds
3. using silencers on the air intakes to gas turbines
4. using mufflers on equipment exhaust
5. running noisy equipment at night when everyone is asleep
   a) 1, 2, 3, 4
   b) 1, 2, 4
   c) 1, 3, 4, 5
   d) 1, 2, 3, 4, 5
   e) 1, 3, 4

Answer 17

e) 1, 3, 4

Question 18

Noise monitors (sound meters) measure the decibel rating and
contain
a) sound dampers
b) sound amplifiers
c) acoustic eliminators
d) weighting networks
e) acoustic amplifiers

Answer 18

d) weighting networks

Question 19

Personal protective devices designed to protect power plant operators
from environmental pollutants, include the following equipment:
1. hard hats
2. ear muffs
3. soft toed shoes or boots
4. safety boots
5. dust masks
6. breathing air packs
a) 1, 2, 4, 5,
b) 1, 2, 3, 4, 5, 6
c) 1, 2, 5, 6
d) 2, 5, 6
e) 3, 4, 6

Answer 19

d) 2, 5, 6