Book 12 Flashcards
Which of these is NOT used for burning coal?
Select one:
a.
Under feed stoker
b.
Rotary cup stoker
c.
Cross feed stoker
d.
Chain grate stoker
Rotary cup stoker
A solenoid type fuel valve;
Select one:
a.
Is held closed by fuel gas pressure
b.
Always opens rapidly
c.
Is held closed by electrical current
d.
Closes slowly
Is held closed by fuel gas pressure
A characteristic of mechanical draft is that the draft:
Select one:
a.
Varies with atmospheric pressure
b.
Varies with chimney height
c.
Varies with chimney temperature
d.
Is properly regulated during all firing conditions
Is properly regulated during all firing conditions
A two element feed water control system compensates for:
Select one:
a.
Level variation
b.
Differential steam flow rate
c.
Feed water temperature variation
d.
Shrink and swell
Shrink and swell
The power requirements for the FD fan of a fluidized bed boiler are ______ times _______ than other boiler designs?
Select one:
a.
1.5, more
b.
3, more
c.
4, more
d.
1.5, less
3, more
The balanced equation for the incomplete combustion of carbon is:
Select one:
a.
C + O2 = CO2 + heat
b.
2C + O2 = CO + heat
c.
C + 2O2 = 2CO + heat
d.
2C + O2 = 2CO + heat
2C + O2 = 2CO + heat
A blowoff tank:
Select one:
a.
Is not classed as a pressure vessel since it is vented
b.
Lowers the temperature and pressure of the incoming boiler water
c.
Must have a safety valve, set to the maximum allowable working pressure of the tank
d.
Accommodates only one boiler
Feedback
Lowers the temperature and pressure of the incoming boiler water
Low fuel pressure in an constant capacity mechanical atomizing oil burner produces:
Select one:
a.
Low excess air requirements
b.
A short blue flame
c.
Gummy deposits in the burner nozzle
d.
Poor atomization
Poor atomization
In a mechanical atomizing burner with three fixed capacity burners, the Intermediate and high fire burner nozzles may have higher capacities than the primary burner nozzle:
Select one:
a.
To give greater firing variations
b.
To prevent pressure surges
c.
Because of the pump being of the positive displacement type
d.
To allow slower boiler warm-ups
To allow slower boiler warm-ups
The main function of a gas burner is:
Select one:
a.
Atomization of the fuel
b.
A source of ignition
c.
Mix the fuel and air
d.
Regulation of the fuel flow
Mix the fuel and air
One way to increase natural draft is to:
Select one:
a.
Incorporate a forced draft fan
b.
Increase the primary air flow
c.
Install a higher chimney
d.
Decrease the amount of excess air
Install a higher chimney
Which of the following is NOT necessary for complete combustion of a fuel?
Select one:
a.
The temperature of the furnace must be high enough
b.
The combustion air must be preheated
c.
Enough time must be allowed for the fuel to burn
d.
The air and fuel must mix thoroughly
The combustion air must be preheated
Solid biofuels can come from a range of sources, except for which of the following?
a.
Wood processing waste
b.
Vegetable waste from food processing industries
c.
Municipal wastes
d.
Ferrous waste from pulp and paper operations
Ferrous waste from pulp and paper operations
The amount of air required to supply just enough oxygen for complete combustion is called the:
Select one:
a.
Excess air
b.
Perfect air
c.
Primary air
d.
Theoretical air
Theoretical air
Which of these groups is the combustible components of coal?
Select one:
a.
Nitrogen, oxygen, ash
b.
Carbon, hydrogen, sulphur
c.
Carbon dioxide, nitrogen, sulphur dioxide
d.
Carbon, ash, nitrogen
Feedback
Carbon, hydrogen, sulphur
The advantage of a steel stack over a reinforced concrete stack is that a steel stack:
Select one:
a.
Is more durable
b.
Requires less maintenance
c.
Has lower cost
d.
Has longer life
Has lower cost
Fluidized bed boilers can successfully burn coal with ash contents as high as
Select one:
a.
30%
b.
55%
c.
60%
d.
70%
70%
Combustion of fuel in a boiler furnace:
Select one:
a.
Requires a higher air-fuel ratio than a diesel engine
b.
Should occur with a minimum of excess air
c.
Is perfect when the stack gases are free of moisture
d.
Requires mechanical draft
Feedback
Should occur with a minimum of excess air
Which of the following is NOT a type of oil burner?
Select one:
a.
Atmospheric burners
b.
Steam atomizing burners
c.
Mechanical or pressure atomizing burners
d.
Centrifugal or rotary cup burners
Atmospheric burners
Efficient combustion is achieved by controlling the:
Select one:
a.
Fuel-air ratio
b.
Net stack temperature
c.
Steam-fuel ratio
d.
Firing rate
Fuel-air ratio
A diaphragm type pressure gauge:
Select one:
a.
Is used to measure high pressures
b.
Operates on a mercury column
c.
Cannot be used for pressures greater than atmospheric
d.
Is used to measure very small pressures
Is used to measure very small pressures
When a modulating mechanical atomization system is used with an oil burner:
Select one:
a.
Air pressure at the burner should be 70 kPa
b.
Dry saturated steam should be used
c.
Very high pump pressure is required for correct atomization
d.
The fuel must be preheated to 90 degrees C
Very high pump pressure is required for correct atomization
Water that leaves a blowoff tank and enters a sewer must not exceed _______ °C:
Select one:
a.
45
b.
50
c.
75
d.
65
65
With a fluid-fired burner, primary and secondary air are swirled in which directions, respectively?
a.
Counter clockwise and clockwise
b.
Clockwise and clockwise
c.
Clockwise and counter clockwise
d.
Counter clockwise and counter clockwise
Clockwise and counter clockwise
Blowoff valves are used to:
Select one:
a.
Drain or remove sediment from the bottom of the steam drum
b.
Drain or remove sediment from the bottom of the boiler
c.
Drain or remove sediment from the continuous blowdown
d.
Reduce the steam pressure on the boiler
Drain or remove sediment from the bottom of the boiler
Which is NOT a fireside surface cleaning method?
a.
Rapping
b.
Acoustic cleaning
c.
Soot blowers
d.
Slagging
Slagging
Retractable soot blowers are installed in a boiler’s radiant heat transfer area including the.
Select one:
a.
Economizer
b.
Secondary air heater
c.
Air preheater
d.
Reheater
Reheater
A condensate receiver low level cutoff switch will:
Select one:
a.
Open a make-up solenoid
b.
Stop the feed pump thereby preventing damage to it
c.
Shut off the boiler
d.
Cause the make-up valve to close
Feedback
Stop the feed pump thereby preventing damage to it
Which of these is NOT one of the undesirable characteristic of flue-gas carbon monoxide?
Select one:
a.
CO pockets in the furnace can be explosive
b.
High flue gas CO means the combustion is inefficient
c.
Less heat of combustion is being released by the fuel
d.
CO causes fireside corrosion
Feedback
CO causes fireside corrosion
This type of boiler condensate return piping arrangement prevents the boiler pressure from forcing boiler water into the return lines:
Select one:
a.
Return line piping
b.
Pipe siphon
c.
Back-flow preventer
d.
Hartford loop
Hartford loop
With regards to chimneys, the flow of combustion air depends on which three things?
a.
The height of the chimney, pressure of the flue gas, and temperature of the cool air column
b.
The height of the chimney, temperature of the flue gas, and temperature of the cool air column
c.
The height of the chimney, pressure of the flue gas, and pressure of the cool air column
d.
The height of the chimney, temperature of the flue gas, and pressure of the cool air column
Feedback
The height of the chimney, temperature of the flue gas, and temperature of the cool air column
One advantage of oil over coal as a fuel is that oil:
Select one:
a.
Burns cleaner
b.
Is more abundant
c.
Is less expensive
d.
Has more fixed carbon
Burns cleaner
The boiler blowoff valves are opened and closed in a specific sequence to:
Select one:
a.
Carry out the blowdown accurately
b.
Prevent excessive water discharge
c.
Maintain the boiler water level
d.
Protect the valve closest to the boiler
Protect the valve closest to the boiler
The amount of pre-mix air to an atmospheric burner is typically:
Select one:
a.
10% to 12%
b.
5% to 8%
c.
20% to 50%
d.
30% to 40%
30% to 40%
The approximate amount of excess air for combustion of a gaseous fuel is:
Select one:
a.
6 - 8%
b.
3 - 5%
c.
10 - 15%
d.
3 - 10%
3 - 10%
A long retractable soot blower:
Select one:
a.
Has nozzles throughout its full length
b.
Is used to clean furnace walls
c.
Rotates and blows while extending and retracting
d.
Blows only when fully extended
Rotates and blows while extending and retracting
In underfeed stokers, underfire air passes through what kind of openings in the grate?
a.
Tweerz
b.
Channel
c.
Retort
d.
Tuyere
Tuyere
A steam boiler must be equipped with two low water fuel cut-off devices when the boiler:
Select one:
a.
Has over 47 m² of heating surface
b.
Has dual fuels
c.
Is not continuously attended
d.
Has two burners
Is not continuously attended
Inlet damper control on a fan:
Select one:
a.
Requires more power to drive the fan when the vanes are closed.
b.
Requires less power to drive the fan at reduced loads.
c.
Is only used on forced draft fans.
d.
Is far less complicated than outlet damper control.
Feedback
Requires less power to drive the fan at reduced loads.
What is the general equation for the combustion process?
a.
Fuel + oxygen yields products of combustion + energy
b.
Endothermic energy + fuel + oxygen yields products of combustion
c.
Fuel + oxygen yields products of combustion + enthalpy
d.
Fuel + oxygen yields products of combustion + exothermic energy
Fuel + oxygen yields products of combustion + energy
Which of the following substances is commonly found in fuel, but is non-combustible?
Select one:
a.
CO
b.
H2
c.
C
d.
H2O
Feedback
H2O
The area of a boiler in which air and fuel combine in a chain reaction to cause sustained burning is the:
Select one:
a.
Baffle
b.
Combustion chamber
c.
Drum
d.
Breeching
Combustion chamber
Natural draft is produced in a boiler furnace when:
Select one:
a.
Hot flue gases contract so that each cubic meter has more mass
b.
Gases in the stack have less mass than an equal column of outside air
c.
Gases in the stack have more mass than an equal column of outside air
d.
Hot flue gases condense
Gases in the stack have less mass than an equal column of outside air
Which wood-like fuels are sourced from grasses and straw, sometimes in the form of chips, hogs, pellets, or bales?
a.
Urban wood fuels
b.
Herbaceous fuels
c.
Wood pellets
d.
Wood chips
Herbaceous fuels
Which of the following burner designs is NOT used for burning oil?
Select one:
a.
Mechanical atomizing burner
b.
Air atomizing burner
c.
Steam atomizing burner
d.
Stoker-type burner
Stoker-type burner
Large capacity burners:
Select one:
a.
Require high flow on ignition
b.
Are very safe relative to puff-back
c.
Require only a small pilot flame
d.
must not have full flow of fuel on startup
must not have full flow of fuel on startup
On a boiler blowoff system, a valve that requires at least five 360° turns of the operating mechanism to change from fully open to fully closed is known as:
Select one:
a.
A quick opening valve
b.
A non-return valve
c.
A slow opening valve
d.
An isolating valve
A slow opening valve
What do natural draft systems that rely on the hot gases in the chimney have?
a.
Less specific gravity than an unequal height column of colder atmospheric air
b.
More density than an equal height column of colder atmospheric air
c.
Less mass than an equal height column of colder atmospheric air
d.
More mass than an equal height column of colder atmospheric air
Less mass than an equal height column of colder atmospheric air
The balanced equation for complete combustion of sulfur is S + O2 = _________:
Select one:
a.
SO2 + heat
b.
2SO2 + heat
c.
SO2
d.
SO2 + S
SO2 + heat
What controls the combustion airflow to the furnace of an older HRT boiler and the flue gas flow from the furnace?
a.
Inlet damper control
b.
Underfire air and motor speed control
c.
Outlet damper control
d.
Overfire air or damper control
Feedback
Overfire air or damper control
The pressure range for pressure-atomizing burners fired with light fuel oil is approximately:
Select one:
a.
50 to 100 kPa
b.
150 to 250 kPa
c.
300 to 550 kPa
d.
550 to 700 kPa
550 to 700 kPa
If there is insufficient combustion air to a boiler furnace, the result will be:
Select one:
a.
High CO2 readings in the flue gas
b.
High CO in the flue gases
c.
A reduction in draft fan power requirements
d.
Higher than normal flue gas temperature
High CO in the flue gases
ASME CSD-1, CW-140 states that each automatically fired, high-pressure steam boiler must have which devices?
a.
At least two automatic low-steam pressure cut-off devices
b.
No low-water fuel cut-off devices
c.
At least two automatic low-water fuel cut-off devices
d.
At least one automatic low-water fuel cut-off devices
At least two automatic low-water fuel cut-off devices
According to the CSA B-51 code, a blowoff tank is necessary to:
Select one:
a.
Prevent high temperature and pressure in the sewer
b.
Prevent blowing off too quickly
c.
Remove sludge from blow-off water
d.
Reduce the boiler water velocity
Prevent high temperature and pressure in the sewer
A multi-burner cluster has secondary and tertiary nozzles ignited by:
Select one:
a.
An igniter spark
b.
An intermittent pilot flame
c.
An interrupted pilot
d.
The primary burner
The primary burner
The simplest way to measure draft is with:
Select one:
a.
A U-tube manometer
b.
A Bourdon tube device
c.
A flexible diaphragm device
d.
A bellows measuring device
A U-tube manometer
A boiler blowoff system is equipped with slow and fast opening valves. The quick opening valve is placed:
Select one:
a.
Closest to the boiler and opened first
b.
Furthest from the boiler and opened first
c.
Closest to the boiler and opened last
d.
Furthest from the boiler and opened last
Closest to the boiler and opened first
A sudden drop in steam pressure causes
Select one:
a.
a sudden increase in drum level
b.
a rapid collapse of steam bubbles in the boiler
c.
“shrinkage”
d.
a single element feedwater control to immediately add water to the drum
a sudden increase in drum level
Shot cleaning pellets are transported to the top of the boiler:
Select one:
a.
Using an air stream
b.
Manually
c.
By a steam injection system
d.
By a hydraulic hoisting system
Using an air stream
An atomizing air compressor is usually:
Select one:
a.
A variable displacement type
b.
A centrifugal type
c.
An axial type
d.
A small, rotary air compressor
A small, rotary air compressor
During a soot blowing operation the boiler firing rate should be at least:
Select one:
a.
15%
b.
50%
c.
20%
d.
80%
50%
Boiler combustion is regulated by:
Select one:
a.
Varying the speed of an ID fan
b.
Controlling or regulating the fuel flow
c.
Varying the speed of an FD fan
d.
Controlling the air and fuel flow
Controlling the air and fuel flow
Which of the following strategies is NOT used to lower the potential for NOX production.
a.
Lowering the mixing time in the burner
b.
Increasing the fuel to air ratio
c.
Treating the combustion gases with chemicals that react with the NOX to produce other compounds
d.
Raising the combustion temperature
Feedback
Raising the combustion temperature
Maximum static pressure in a fuel oil line before the oil pump is limited by code to approximately:
Select one:
a.
10 kPa
b.
15 kPa
c.
35 kPa
d.
70 kPa
35 kPa
Which element in air will combine with the combustible elements of the fuel?
Select one:
a.
Nitrogen
b.
Oxygen
c.
Hydrogen
d.
Carbon dioxide
Oxygen
Soot blowers are essential equipment on a boiler fired with:
Select one:
a.
Natural gas
b.
Solid fuels
c.
Propane
d.
Butane
Solid fuels
For boilers operating above 690 kPa, what is the requirement for the blowoff piping?
a.
Have bends using 90° elbows
b.
Be made of galvanized piping
c.
Be at least Schedule 80 steel
d.
Have malleable iron fittings of Class 150 and Class 300
Feedback
Be at least Schedule 80 steel
One of the advantages of using natural gas as a fuel in a boiler is:
Select one:
a.
No storage space is required
b.
Low cost
c.
Abundance in supplies
d.
No standby fuel is necessary
No storage space is required
The result of a condensate receiver that is too small could be:
Select one:
a.
High boiler water level
b.
Overflowing of the condensate receiver
c.
Loss of make-up water
d.
Low make-up water flow rates
Overflowing of the condensate receiver
The inclined “U” tube manometer:
Select one:
a.
Will measure pressure in kPa
b.
Can only be used with mercury
c.
Is more accurate than a “U” tube manometer
d.
Is more difficult to read
Is more accurate than a “U” tube manometer
Which of the following is NOT a pilot for a gas burner?
Select one:
a.
Continuous
b.
Intermittent
c.
Manual
d.
Interrupted
Manual
If not enough combustion air is given to an oil-fired flame:
Select one:
a.
The flame will be dark and smoky
b.
The flame will be bluish with yellow tips
c.
Light gray smoke will leave the stack
d.
The flame will be bright yellow
The flame will be dark and smoky
One operating variable that is manipulated relatively easily and which the operators of FBC boilers must always be aware, is:
Select one:
a.
Slag production
b.
Fuel type variation
c.
Coal introduction techniques
d.
Bed expansion
Bed expansion
Balanced draft:
Select one:
a.
Requires weights on the dampers to balance them.
b.
Requires a tall smoke stack
c.
Uses a forced draft and an induced draft fan
d.
Is used for furnaces with positive pressure
Uses a forced draft and an induced draft fan
What does a short, single-nozzle retractable wall blower remove?
a.
Deposits located in the superheater and reheater banks
b.
Water-wall ash deposits
c.
Deposits from the radiant heating surfaces
d.
Deposits from the convection surfaces
Water-wall ash deposits
Gas burners for heating boilers can be divided into two general classes:
Select one:
a.
Mixing and non-mixing
b.
Refractory and ribbon-type
c.
In-shot and up-shot
d.
Pre and after mix
Pre and after mix
The Hartford loop will:
Select one:
a.
Only be installed on multiple-boiler systems
b.
Ensure continuous circulation of a hot water system
c.
Prevent boiler water level from going below the lowest safe water level
d.
Replace the feedwater check valve
Prevent boiler water level from going below the lowest safe water level
In a float type low water fuel cutoff, the main purpose of the mercury switch is to:
Select one:
a.
Open the burner circuit when the level is high
b.
Close the burner circuit when the level is low
c.
Activate a low water alarm
d.
Open the burner circuit when the level is low
Open the burner circuit when the level is low
Dissolved oxygen in condensate:
Select one:
a.
Will cause waterside corrosion
b.
Can cause scaling on the return lines
c.
Is removed with amines
d.
Necessitates the installation of a deaerator
Feedback
Will cause waterside corrosion
A diaphragm draft gauge on a furnace indicates the draft in:
Select one:
a.
mm of water column
b.
kPa
c.
MPa
d.
psi
mm of water column
What does the frequency of a blowdown depend on?
a.
Condensate flow rate
b.
Rate of chemical addition
c.
Rate of steam production
d.
Blowoff piping design
Rate of steam production
Stationary soot blowers are installed in the:
Select one:
a.
Reheater bank
b.
Primary superheater bank
c.
Secondary superheater bank
d.
Convection zones
Convection zones
In a typical bubbling fluidized bed boiler, to what depth is the combustion bed maintained?
Select one:
a.
1.5 metres
b.
1 metre
c.
2 metres
d.
2.5 metres
1 metre
When a gas-fired burner is operating properly:
Select one:
a.
The flame will be blue with short yellow tips
b.
The furnace will pulsate
c.
There will be no turbulence
d.
It will have a long, bright, yellow flame
The flame will be blue with short yellow tips
Due to the comparative size of FBC power plants, a significant saving is gained in:
Select one:
a.
Fuel and waste costs
b.
Material and construction costs
c.
“Clinker” and soot blowing costs
d.
Fuel storage costs
Material and construction costs
The steam used for soot blowing is usually:
Select one:
a.
Low pressure
b.
Unsaturated steam
c.
The same as boiler drum pressure
d.
Superheated at the soot blower nozzle
Superheated at the soot blower nozzle
A thermo hydraulic feed water regulator uses _____ as operating media.
Select one:
a.
Oil and nitrogen
b.
CO2 and water
c.
Water and steam
d.
Air and water
Water and steam
When using mechanical fuel oil atomization:
Select one:
a.
70 kPa steam pressure is required at the burner
b.
Dry saturated steam or superheated steam should be used
c.
High pump pressure is required
d.
35 to 40 kPa oil pressure is required
High pump pressure is required
Proper draft is important to the plant operator because it:
Select one:
a.
Produces efficient combustion
b.
Keeps the furnace from overheating
c.
Reduces the quantity of ash produced
d.
Prevents flue gas from leaking out of the boiler
Produces efficient combustion
What does the operating mechanism of a slow-opening valve require?
a.
Moving a lever through a small arc of about 90°
b.
A sliding disc that can cut through impurities
c.
Markings on the valve body indicating open and close positions
d.
At least five 360° turns to change from fully closed to fully open
At least five 360° turns to change from fully closed to fully open
Water formed from the condensing of steam is called:
Select one:
a.
Water
b.
Wet steam
c.
Condensate
d.
Waste water
Condensate
A refractory burner disadvantage is:
Select one:
a.
High cost due to complexity
b.
Too much fuel preheat
c.
Low radiant heat
d.
Low combustion efficiency
High cost due to complexity
As a general rule the size of the condensate receiver should be large enough to hold a volume of condensate equal to the water evaporated by the boiler in a _____ period.
Select one:
a.
One and one half hour
b.
One hour
c.
45 minute
d.
20 to 30 minute
20 to 30 minute
Using lower combustion temperatures with fluidized bed combustion reduces the:
Select one:
a.
Production of hot flue gases
b.
Boiler efficiency
c.
Production of NOX
d.
Turbulence of the furnace interior
Production of NOX
Limestone, when added to a fluidized bed boiler
Select one:
a.
Lowers the combustion bed temperature
b.
Acts as a de-sulphuring agent
c.
Absorbs NOx
d.
Reduces greenhouse gas emissions
Acts as a de-sulphuring agent
The low water fuel cut-off of heating boiler must shut the fuel off if the water level drops:
Select one:
a.
Below the top row of tubes
b.
Quickly
c.
To an unsafe level
d.
The lowest permissible water level
To an unsafe level
The major disadvantages of oil over coal is that oil:
Select one:
a.
Does not burn as clean
b.
Is more difficult to control
c.
Is more expensive and less abundant
d.
Requires more storage space
Is more expensive and less abundant
The stack temperature of a boiler can rise if:
Select one:
a.
Excess air is reduced
b.
The fireside of the boiler becomes dirty
c.
The percentage of CO in the flue gas rises
d.
The rate of fuel flow decreases
The fireside of the boiler becomes dirty
The typical time required to heat a fluidized bed to ignition temperature prior to the introduction of coal is:
Select one:
a.
One hour
b.
30 minutes
c.
Two hours
d.
Three hours
One hour
