A-12 Elements of Boiler Systems Flashcards
(20 cards)
When the intermittent blowoff valves on a boiler are both seatless, the correct operating sequence is:
A. The valve furthest from the boiler is opened first and closed last
B. The valve closest to the boiler is opened first and closed last
C. The valve furthest from the boiler is opened first and closed last
D. The valve closest to the boiler is opened first and closed first
A. The valve furthest from the boiler is opened first and closed last
A float operated level control:
A. Will recognize swell and shrinkage and correct the feedwater flow
B. Will have the float in the boiler drum
C. Is only used on small boilers
D. Is used on fire tube boilers only
C. Is only used on small boilers
On a boiler blowoff system, a valve that required at least five 360 degree turns of the operating mechanism to change from fully open to fully closed is known as:
A. A quick opening valve
B. A non-return valve
C. A slow opening valve
D. An isolating valve
C. A slow opening valve
If there is insufficient combustion air to a boiler furnace, the result will be:
A. High CO2 readings in the flue gas
B. High CO in the flue gas
C. A reduction in draft fan power requirements
D. Higher than normal flue gas temperature
B. High CO in the flue gasses
The complete combustion of carbon is represented by the balanced equation C+O2= :
A. CO
B. CO + Heat
C. CO2 + Heat
D. 2CO2
C. CO2 + heat
When shrinkage occurs, what does a single-element feedwater control detect?
A. Decrease in drum level
B. Increase in drum level
C. Increase in steam flow
D. Decrease in feedwater flow
A. Decrease in drum level
The ____ fan blows combustion air into the wind box of a boiler.
A. Induced draft
B. High pressure
C. Balanced draft
D. Forced draft
D. Forced draft
A steam boiler is blown off intermittently in order to:
A. Clean the soot and carbon out of the firebox and tubes
B. Lower the dissolved solids concentration in the boiler
C. Discharge sediment and scale-forming matter from the boiler
D. Locate the steam level
C. Discharge sediment and scale-forming matter from the boiler
Spot blowers are essential equipment on a boiler fired with:
A. Natural gas
B. Solid fuels
C. Propane
D. Butane
B. Solid fuels
When a boiler equipped with a combination feedwater control and low water cutoff device shuts down due to a low water condition:
A. The level must be restored to above the cutoff line before the unit can be restarted
B. It can be restarted by pressing the manual reset
C. The operator must open the feeder valves to allow water into the boiler
D. The condensate pump must be restarted
A. The level must be restored to above the cutoff line before the unit can be restarted
Natural draft is produced in a boiler furnace when:
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
B. Gases in the stack have less mass than an equal column of outside air
One advantage of oil over coal as a fuel is that oil:
A. Burns cleaner
B. Is more abundant
C. Is less expensive
D. Has more fixed carbon
A. Burns cleaner
Combustion of fuel in a boiler furnace:
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
B. Should occur with a minimum of excess air
The compressed air used as atomizing air in the air atomizing oil burner is also called:
A. Secondary air
B. Primary air
C. Pre-mixed air
D. Combustion air
B. Primary air
Efficient combustion is achieved by controlling the:
A. Fuel-air ratio
B. Net stack temperature
C. Steam-fuel ratio
D. Firing rate
A. Fuel-air ratio
When a modulating mechanical atomization system is used with an oil burner:
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
C. Very high pump pressure is required for correct atomization
Which of the following substances is commonly found in fuel, but is non-combustible?
A. CO
B. H2
C. C
D. H2O
D. H2O
Carbon that is not combined with hydrogen is referred to as:
A. Mono-carbon
B. Separated carbon
C. Free carbon
D. Fixed carbon
D. Fixed carbon
Fluidized bed plants can be built smaller than other designs because of:
A. Higher steam temperature and pressures
B. Higher heat transfer rages and the abscene of wet exhaust scrubbing equipment
C. Less slag production and the elimination of soot blowing equipment
D. The use of smaller burners
B. Higher heat transfer rates and the absence of wet exhaust scrubbing equipment
A diaphragm type pressure gauge:
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
D. Is used to measure very small pressures
