chapter 13

Question 1

Low excess combustion air in a boiler will likely cause:

a) soot
b) high CO2
c) spalling
d) puffback

Answer 1

a

Question 2

The combustible components of coal are:

a) Carbon, hydrogen, nitrogen
b) Carbon, hydrogen, sulphur
c) Carbon, hydrogen
d) Carbon, hydrogen, oxygen

Answer 2

b

Question 3

Modern flue gas analyzers measure the amount of _____________ in flue gases.

a)Carbon dioxide, carbon monoxide, flue temperature
b)Carbon dioxide, carbon monoxide, oxygen
c)Carbon dioxide
d)Carbon, carbon monoxide, nitrogen

Answer 3

b

Question 4

Fuel oils are derived from:

a)Natural gas
b)Petroleum
c)Coal
d)Electricity

Answer 4

b

Question 5

To find draft in a boiler, measure the difference between the furnace pressure and _______________ pressure.

a)Atmospheric
b)Steam
c)Dynamic
d)Blower

Answer 5

a

Question 6

Carbon monoxide in the flue gas is a sign of

a)complete combustion
b)incomplete combustion
c)stoichiometric combustion
d)perfect combustion

Answer 6

b

Question 7

The device for measuring draft is called:

a)Barometer
b)Diaphragm
c)Bourdon tube
d)Manometer

Answer 7

d

Question 8

A draft diverter:

a)Maintains constant pressure through the forced draft fan
b)Maintains constant furnace temperature for combustion
c)Maintains a constant and limited draft for combustion on natural draft burner
d)Maintains constant chimney temperature

Answer 8

c

Question 9

The windbox is:

a) Another name for the chimney
b) The space at the rear tubesheet of a firebox boiler where flue gases turn to make the next succeeding pass
c) The box around the burner damper that collects the output from the blower
d) The box at the last pass of the boiler that collects flue gases and funnels them toward the chimney

Answer 9

c

Question 10

Draft

a) Is the movement of air from a high pressure region to a low pressure region
b) Depends on the difference in density between the boiler’s exiting flue gases and the entering combustion air
c) Would increase if the height of the chimney were to be increased
d) a) and c)
e) All of the above

Answer 10

e

Question 11

The Inclined Draft Gauge offers this advantage over the U-tube draft gauge:

a)Measures slight pressure fluctuations more accurately
b) Smaller
c) Does not require to be level to be accurate
d) All of the above

Answer 11

a

Question 12

In the SI system of units, draft is typically measured in:

a) Millimetres of water column
b) kPa
c) Feet of head
d) psi

Answer 12

a

Question 13

In order to produce a continuous flow of air and gas through the boiler a __________ is required

a) specific gravity difference
b) pressure difference
c) velocity difference
d) temperature difference

Answer 13

b

Question 14

___________ is the most widely used oil for packaged firetube boilers

a) #5 Fuel Oil
b) #2 Fuel Oil
c) Bunker C
d) Kerosene

Answer 14

b

Question 15

Conditions for complete combustion include ________________.
a) Thorough mixing of water and fuel
b) Cool heating surfaces
c) Enough air
d) Low furnace temperature

Answer 15

c

Question 16

The spark electrodes that ignites the burner pilot are typically:

a) 24 V
b) 120 V
c) 10,000 - 12,000 V
d) 10,000 - 12,000 A

Answer 16

c

Question 17

Low excess combustion air in a boiler will likely cause:

a) puffback
b) spalling
c) soot
d) high CO2

Answer 17

c

Question 18

The forced draft fan is used to force:

A.Combustion air into the furnace
B.Combustion air into the stack
C.Flue gases into the stack
D.Flue gases into the furnace
E.Combustion produces into the stack

Answer 18

a

Question 19

One inch of water is equivalent to:

A.14.7 psi (101.4 kPa)
B.0.145 psi (1.0 kPa)
C.0.36 psi (2.46 kPa)
D.0.00014 psi (0.0009 Pa)
E.0.036 psi (0.25 kPa)

Answer 19

e

Question 20

The draft created by the fan can be controlled by the:

A.Use of inlet dampers
B.Speed of the dampers
C.Temperature of the flue gases
D.Height of the stack
E.Amount of fuel supplied

Answer 20

a

Question 21

The term Relative Density (specific gravity) means:

A.The ratio of the mass of a certain volume of oil to the mass of an equal mass of oil
B.The ratio of the volume of a certain mass of oil to the mass of an equal volume of water
C.The ratio of the mass of a certain volume of oil to the volume of an equal mass of water
D.The ratio of the mass of a certain volume of oil to the mass of an equal volume of water
E.The ratio of the mass of a certain volume of water to the mass of an equal volume of water

Answer 21

d

Question 22

A U-tube draft gauge is also known as a:

A.Manometer
B.Viscometer
C.Psychrometer
D.Pressure gauge
E.Thermometer

Answer 22

a

Question 23

In buildings the fuels that are widely used are:
1. Oil
2. Coal
3. Natural gas
4. Hog fuel
5. Garbage

A.2, 3, 5
B.1, 2
C.1, 2, 3
D.2, 4
E.1, 3

Answer 23

e

Question 24

Propane as a liquid takes as little as _____ of the space it needs as a gas, making it easy to store and transport and then burn as a gas.

A.1/150th
B.1/12th
C.1/120th
D.1/10th
E.1/100th

Answer 24

c

Question 25

Air is composed of mostly:

A.Oxygen
B.Helium
C.Nitrogen
D.Smog
E.Carbon dioxide

Answer 25

c

Question 26

The amount of air in excess of the theoretical air 12 kg (26.5 lb) is 6 kg (13.2 lb) expressed as a percentage of the theoretical air this would be:

A.30%
B.20%
C.10%
D.15%
E.50%

Answer 26

e

Question 27

If the combustion is complete the carbon will combine with the oxygen to produce _____ plus heat.

A.Sulphur monoxide
B.Carbon monoxide
C.Sulphur dioxide
D.Water vapour
E.Carbon dioxide

Answer 27

e

Question 28

the incomplete combustion of carbon results in the formation of carbon ____________

a. terachloride
b. monoxide
c. dioxide
d.trioxide

Answer 28

b

Question 29

when a unit amount of fuel is burned completley, the heat produced is called the __________of the fuel

a. heat content
b. heating value
c. excess air
d. combustion efficiency

Answer 29

b

Question 30

the conditions for complete combustion include

a. low furnace temp
b. cool heating surfaces
c. thorough mixing of water and fuel
d. enough air

Answer 30

d

Question 31

the amount of air required to supply just enough oxygen for complete combustion is called _______ air

a. excess
b. theoretical
c. tertiary
d. primary

Answer 31

b

Question 32

_________ forms the greatest percentage of the combustible elements in fuel

a. sulfur
b. hydrogen
c. carbon
d. wood

Answer 32

c

Question 33

an advantage of using natural gas as fuel is

a. more storage space is required
b. has less heating value than oil
c. less expensive than coal
d. easily mixed with air

Answer 33

d

Question 34

a draft system that is motorized and mounted on the front of the boiler is ___________ draft

a. natural
b. forced
c. induced
d. balanced

Answer 34

b

Question 35

a pressure explosion of a boiler may occur if

a. the gas pressure to the burner is too high
b. feedwater pressure is too high
c. low boiler water level produces weakening of tubes
d. the safety valve opens too early

Answer 35

c