Power Engineering 3B1 Chapter 8 UPDATED ACTUAL Questions and
CORRECT Answers
Question: A single element feedwater system compensates for variations in
Correct Answer: a. Level and pressure b. Shrinkage and swell c. Level only d. Pressure only e. flow only:
c
Question: With On - Off boiler feed water control, water is supplied _____________ to the boiler, either by
fully opening or fully closing a valve in the feedwater line. a. partially b. intermittently c. fully d. steadily
Correct Answer: b
Question: In ______ control, a change in drum level causes a proportional change in output from the
transmitter to reposition the feedwater control valve to correct the drum level setpoint. a. proportional b.
reset c. feedback d. water
Correct Answer: c
Question: A rapid increase in boiler load causes an immediate increase in steam flow from the boiler,
which creates a sudden _____ in the boiler steam drum pressure. a. drop b. increase c. change d.
temperature
Correct Answer: a
Question: A sudden increase in load, a decrease in drum pressure, and an immediate increase in heat
release, is called ______. a. rate b. swell c. shrinkage d. condensing
Correct Answer: b
Question: The two-element feedwater control system, is similar to the single element type, only with a
______ flow transmitter added. a. fuel b. feedwater c. air d. steam
Correct Answer: d
Question: A two-element control system may be called a _________ system as it anticipates what will
happen to the drum level with a change in load and acts accordingly to avoid large level fluctuations. a.
reverse feed b. feed-forward c. good d. smart
Correct Answer: b
Question: Two-element system in feedwater regulation will compensate for
Correct Answer: a. Feedwater pressure and level variations b. Shrinkage and swell c. Steam flow
variations d. Level, shrinkage and swell variations e. level and steam flow variations: d
Question: Shrinkage may be the result of
Correct Answer: 1. A reduction in boiler output 2. An increase in firing rate 3. A decrease in firing rate 4.
An increase in steam drum pressure a. 1,3,4 b. 1,2,3 c. 2,3,4 d. 1,2,4 e. 1,2,3,4: a
Question: A steam generator usually has a greater water volume in the tube section than the drum section.
Consequently
Correct Answer: a. Fuel flow control is most critical b. Feedwater control is most critical c. Feedwater
pressure is most critical d. Air flow control is most critical e. steam drum pressure is most critical: b
Question: Three-element feedwater control compensates for
, Correct Answer: 1. Level variation 2. Steam flow variation 3. Feedwater flow variation 4. Shrinkage and
swell a. 2,3,4 b. 1,3,4 c. 1,2,4 d. 1,2,3,4 e. 1,2,3: d
Question: The three-element feedwater control system overcomes the effects of swell and shrinkage and
also responds to _________ flow a. fuel b. steam c. feedwater d. blowdown
Correct Answer: c
Question: A square root extractor is used to produce an _______ that is proportional to the steam flow. a.
output b. input c. setpoint d. result
Correct Answer: a
Question: An increase in boiler load or steam flow causes a proportional increase in the steam flow signal
and an increase in output of the computing relay which becomes the set point in the controller. a. True b.
False
Correct Answer: a
Question: A direct pressure combustion control system, may be used on boilers where the fuel flow is
________ to measure. a. easy b. difficult c. necessary d. important
Correct Answer: b
Question: An oxygen analyzer can also be provided to indicate the excess oxygen in the flue gas, assisting
the operator to control the excess air and increasing boiler _______. a. load b. firing c. temperature d.
efficiency
Correct Answer: d
Question: Combustion regulation is a function of
Correct Answer: a. Steam drum pressure b. Fuel flow c. Air flow d. Fuel-air ratio e. Feed water flow: a
Question: A pressure modulating control (pressuretrol)
Correct Answer: a. Maintains a constant firing rate b. Will vary fuel and air supply according to steam
pressure c. Cannot be adjusted d. Can vary fuel and air supply separately e. Starts and stops the burner at
predetermined settings: b
Question: Direct combustion control measures and responds to
Correct Answer: a. Air flow and steam pressure b. Air flow and fuel flow c. Steam pressure only d. Steam
pressure and fuel flow e. Steam pressure and steam flow: c
Question: On a coal fired unit using a stoker and obtaining good combustion efficiency we would probably
use
Correct Answer: a. Steam flow-air flow control b. Fuel flow-air flow control c. Air flow-fuel flow control
d. Direct control e. Positioning control: a
Question: By measuring and comparing the steam and the ________, it is possible to obtain efficient
combustion in a boiler by maintaining a proper steam to airflow ratio. a. feedwater b. fuel c. airflow d. drum
level
Correct Answer: c
Question: In coal fed to the furnaces, the airflow is measured and maintained in a predetermined ratio with
the steam flow. a. True b. False
CORRECT Answers
Question: A single element feedwater system compensates for variations in
Correct Answer: a. Level and pressure b. Shrinkage and swell c. Level only d. Pressure only e. flow only:
c
Question: With On - Off boiler feed water control, water is supplied _____________ to the boiler, either by
fully opening or fully closing a valve in the feedwater line. a. partially b. intermittently c. fully d. steadily
Correct Answer: b
Question: In ______ control, a change in drum level causes a proportional change in output from the
transmitter to reposition the feedwater control valve to correct the drum level setpoint. a. proportional b.
reset c. feedback d. water
Correct Answer: c
Question: A rapid increase in boiler load causes an immediate increase in steam flow from the boiler,
which creates a sudden _____ in the boiler steam drum pressure. a. drop b. increase c. change d.
temperature
Correct Answer: a
Question: A sudden increase in load, a decrease in drum pressure, and an immediate increase in heat
release, is called ______. a. rate b. swell c. shrinkage d. condensing
Correct Answer: b
Question: The two-element feedwater control system, is similar to the single element type, only with a
______ flow transmitter added. a. fuel b. feedwater c. air d. steam
Correct Answer: d
Question: A two-element control system may be called a _________ system as it anticipates what will
happen to the drum level with a change in load and acts accordingly to avoid large level fluctuations. a.
reverse feed b. feed-forward c. good d. smart
Correct Answer: b
Question: Two-element system in feedwater regulation will compensate for
Correct Answer: a. Feedwater pressure and level variations b. Shrinkage and swell c. Steam flow
variations d. Level, shrinkage and swell variations e. level and steam flow variations: d
Question: Shrinkage may be the result of
Correct Answer: 1. A reduction in boiler output 2. An increase in firing rate 3. A decrease in firing rate 4.
An increase in steam drum pressure a. 1,3,4 b. 1,2,3 c. 2,3,4 d. 1,2,4 e. 1,2,3,4: a
Question: A steam generator usually has a greater water volume in the tube section than the drum section.
Consequently
Correct Answer: a. Fuel flow control is most critical b. Feedwater control is most critical c. Feedwater
pressure is most critical d. Air flow control is most critical e. steam drum pressure is most critical: b
Question: Three-element feedwater control compensates for
, Correct Answer: 1. Level variation 2. Steam flow variation 3. Feedwater flow variation 4. Shrinkage and
swell a. 2,3,4 b. 1,3,4 c. 1,2,4 d. 1,2,3,4 e. 1,2,3: d
Question: The three-element feedwater control system overcomes the effects of swell and shrinkage and
also responds to _________ flow a. fuel b. steam c. feedwater d. blowdown
Correct Answer: c
Question: A square root extractor is used to produce an _______ that is proportional to the steam flow. a.
output b. input c. setpoint d. result
Correct Answer: a
Question: An increase in boiler load or steam flow causes a proportional increase in the steam flow signal
and an increase in output of the computing relay which becomes the set point in the controller. a. True b.
False
Correct Answer: a
Question: A direct pressure combustion control system, may be used on boilers where the fuel flow is
________ to measure. a. easy b. difficult c. necessary d. important
Correct Answer: b
Question: An oxygen analyzer can also be provided to indicate the excess oxygen in the flue gas, assisting
the operator to control the excess air and increasing boiler _______. a. load b. firing c. temperature d.
efficiency
Correct Answer: d
Question: Combustion regulation is a function of
Correct Answer: a. Steam drum pressure b. Fuel flow c. Air flow d. Fuel-air ratio e. Feed water flow: a
Question: A pressure modulating control (pressuretrol)
Correct Answer: a. Maintains a constant firing rate b. Will vary fuel and air supply according to steam
pressure c. Cannot be adjusted d. Can vary fuel and air supply separately e. Starts and stops the burner at
predetermined settings: b
Question: Direct combustion control measures and responds to
Correct Answer: a. Air flow and steam pressure b. Air flow and fuel flow c. Steam pressure only d. Steam
pressure and fuel flow e. Steam pressure and steam flow: c
Question: On a coal fired unit using a stoker and obtaining good combustion efficiency we would probably
use
Correct Answer: a. Steam flow-air flow control b. Fuel flow-air flow control c. Air flow-fuel flow control
d. Direct control e. Positioning control: a
Question: By measuring and comparing the steam and the ________, it is possible to obtain efficient
combustion in a boiler by maintaining a proper steam to airflow ratio. a. feedwater b. fuel c. airflow d. drum
level
Correct Answer: c
Question: In coal fed to the furnaces, the airflow is measured and maintained in a predetermined ratio with
the steam flow. a. True b. False
