Introduction to Boiler Combustion Flashcards
The purpose of combustion controls is to:
1. control fuel flow and air flow into the furnace
2. maintain the proper ratio of air to flue gas
3. maintain the proper ratio of air to fuel
4. maintain the correct furnace pressure in a balanced
system
5. maintain a negative pressure in the furnace when
using a force draft fan
a) 1, 2, 3
b) 2, 3, 4
c) 3, 4, 5
d) 1, 3, 4
e) 2, 4, 5
d) 1, 3, 4
The combustion equation C + O2 =
a) CO
b) CO + heat
c) CO2 + heat
d) 2 CO2
e) 2C + 2O
c) CO2 + heat
The combustion equation 2 H2 + O2 =
a) H2O + heat
b) H2O
c) 2 H2O
d) 2 H2O + heat
e) 2H + O2
d) 2 H2O + heat
The combustion equation S + O2 =
a) SO2 + heat
b) 2 SO2 + heat
c) SO2
d) SO2 + S
e) 2S + O
a) SO2 + heat
Which of the following supports combustion?
a) smoke
b) oxygen
c) nitrogen
d) hydrogen
e) carbon dioxide
b) oxygen
Which of the following are necessary to complete combustion
of a fuel:
1. enough air must be supplied
2. the temperature of the furnace must be high enough
3. there must be enough water in the boiler
4. enough time must be allowed for the fuel to burn
5. the safety valve must be properly set
6. the air and fuel must be thoroughly mixed together
a) 1, 3, 4, 6
b) 2, 3, 4, 5
c) 1, 2, 4, 6
d) 1, 2, 3, 4
e) 3, 5, 6
c) 1, 2, 4, 6
Which element in the air will combine with the combustible elements of the fuel? a) nitrogen b) oxygen c) hydrogen d) carbon dioxide e) carbon monoxide
b) oxygen
The amount of air required to supply just enough oxygen for complete combustion is called the a) exact air b) perfect air c) primary air d) theoretical air e) secondary air
d) theoretical air
Combustion air openings are required by code and combustion
air can be said to be
a) all air which contacts the raw fuel before the burner
b) all air which contributes to the completion of combustion
c) excess air
d) all air which enters the boiler furnace, including high
excess air
e) atomizing air
b) all air which contributes to the completion of combustion
The amount of excess air required for combustion is
determined by the
a) ambient temperature of the outside air
b) air supply pressure
c) size of the boiler
d) load on the boiler
e) composition and condition of the fuel
e) composition and condition of the fuel
Insufficient air for combustion will result in:
- carbon in flue gases
- high oxygen reading in flue gases
- low oxygen reading in flue gases
- high CO in flue gases
- higher than normal flue gas temperature
a) 1, 2, 3
b) 3, 4, 5
c) 1, 3, 4
d) 2, 3, 4
e) 1, 3, 5
c) 1, 3, 4
The approximate amount of excess oxygen for gaseous fuel is
a) 10%
b) 7%
c) 5%
d) 15%
e) 2%
e) 2%
The approximate amount of excess air for fuel oil is
a) 20%
b) 15%
c) 10%
d) 5%
e) 2%
b) 15%
In winter, the white smoke coming from the stack is
a) wet steam from combustion of the hydrogen in the fuel
b) carbon dioxide
c) sulphur dioxide
d) carbon monoxide from incomplete combustion of the carbon
in the fuel
e) unburned hydrogen
a) wet steam from combustion of the hydrogen in the fuel
Black smoke can be caused by
a) insufficient combustion air
b) too high a boiler pressure
c) too much nitrogen in the air
d) too much combustion air
e) high temperature combustion air
a) insufficient combustion air
Carbon monoxide is both explosive and
a) inert
b) expensive
c) non-compressible
d) grey in colour
e) toxic
e) toxic
The refining process for fuel oils involves separating the
crude oil into end products which have distinguishing
characteristics such as specific gravity, viscosity, and
a) colour
b) odour
c) heating value
d) boiling point
e) solids content
d) boiling point
A major disadvantage of oil over coal is
a) the oil does not burn as clean
b) oil is more difficult to control
c) oil is more expensive and less abundant
d) coal requires less storage space
e) oil requires more handling labour
c) oil is more expensive and less abundant
Ethane is a component of natural gas and constitutes a percent volume of a) 10 - 20% b) 80 - 90% c) 60 - 70% d) 5 - 10% e) 30 - 40%
a) 10 - 20%
Using preheated air with solid fuels
a) increases air pollution
b) creates soot which is heavy and difficult to remove
c) necessitates the use of better grades of fuel
d) reduces the stack temperature
e) starts combustion more quickly
e) starts combustion more quickly
Engineers must understand the importance of combustion in order to: 1. order the right grade of fuel 2. burn the fuel completely 3. produce smokeless fires 4. minimize the danger of explosion a) 1, 2 b) 1, 3 c) 2, 3 d) 1, 2, 3, 4 e) 2, 3, 4
d) 1, 2, 3, 4
Carbon which is not combined with hydrogen is referred to as a) mono-carbon b) loose carbon c) separated carbon d) ununited carbon e) fixed carbon
e) fixed carbon
To which of the following oil burners is the oil supplied under high pressure? a) mechanical atomizing burner b) air atomizing burner c) rotary cup burner d) steam atomizing burner e) multi-spud burner
a) mechanical atomizing burner
When using mechanical fuel oil atomization
a) 70 kPa steam pressure is required at the burner
b) 35 to 40 kPa oil pressure is required
c) high pump pressure is required
d) steam pressure is required to keep the bypass open
e) dry saturated steam or superheated steam should be used
c) high pump pressure is required
