1
Q
- What is the main purpose of baffles in the setting of a boiler?
a. To supply strength to the setting
b. To allow hot gases to make more than one pass through a boiler
c. To produce eddy currents
d. To cause a restriction of gas flow
e. To mix the fuel gas and the combustion air for complete combustion
A
b. To allow hot gases to make more than one pass through a boiler
2
Q
- Which of the following are disadvantages of using baffles in a boiler setting?
1) Eddy currents can be produced
2) Increased friction can result
3) Coal fired boilers can result in pockets of ash accumulation
4) Heat transfer is increased
a. 1, 2, 3, 4
b. 1, 2, 3
c. 2, 3, 4
d. 2, 4
e. 1, 3, 4
A
b. 1, 2, 3
3
Q
- In order to direct the flow of combustion gas over the tubes in a watertube boiler, it is necessary to use ____.
a. baffles
b. deflectors
c. fans
d. preheaters
A
a. baffles
4
Q
- Baffles can be placed so as to cause the gases to flow at right angles to the tube length, in which case they are called ________ baffles.
a. longitudinal
b. cross
c. back
d. straight
A
b. cross
5
Q
- Baffles may be placed so as to cause the gases to flow parallel to the tubes, in which case they are called _________ baffles.
a. longitudinal
b. cross
c. back
d. straight
A
a. longitudinal
6
Q
- Baffles are usually constructed of ___________ material and may be made up of individual bricks or tiles.
a. steel
b. castable
c. refractory
d. insulation
A
c. refractory
7
Q
- Curved or streamlined baffles have the ________ of having no sharp turns to cause eddy currents, increase friction, or form pockets for ash accumulation.
a. disadvantage
b. habit
c. source
d. advantage
A
d. advantage
8
Q
- Metal fin bars are welded to adjacent tubes, forming a continuous surface and a pressure-tight wall, this is referred to as a welded fin tube wall or a ________ wall.
a. solid
b. membrane
c. screen tube
d. tangent tube
A
b. membrane
9
Q
- A wall suitable for severe service, here the tubes are side by side and touching each other, this is called a ________ wall.
a. solid
b. membrane
c. screen tube
d. tangent tube
A
d. tangent tube
10
Q
- Flat plates or studs are welded to each side of the tubes, this is called a _______ wall.
a. flat stud tube
b. screen tube
c. tangent tube
d. membrane
A
a. flat stud tube
11
Q
- In the watertube boiler, water cooling of the furnace is achieved by arranging tubes to form all or part of the furnace walls. Which of the following refers to this type of construction?
1) Tangent tube wall
2) Fin-welded tubes
3) Tube and brick wall
4) Flat-stud tube wall
a. 1, 2, 3, 4
b. 2, 3
c. 2, 3, 4
d. 1, 2
e. 1, 3
A
a. 1, 2, 3, 4
12
Q
- Steam produced from water in a boiler is at saturation temperature and usually contains a certain amount of moisture. The purpose of the superheater is:
1) To save on chemical make-up to the boiler
2) That any moisture present in the steam will be evaporated
3) Is to help protect the turbine blades from erosion
4) Is to allow more work per kg of steam
a. 1, 4
b. 1, 2
c. 2, 3
d. 2, 3, 4
e. 1, 3
A
d. 2, 3, 4
13
Q
- Which of the following are integral superheaters?
1) High pressure types
2) Convection types
3) Radiant types
4) High temperature types
a. 1, 4
b. 1, 3
c. 2, 3
d. 3, 4
e. 2, 4
A
c. 2, 3
14
Q
- What does a “rising steam temperature characteristic” mean?
1) At low loads, the steam temperature will be low
2) The superheated steam temperature will rise as the firing rate or boiler output increases
3) At high loads, the steam temperature will be high
4) The temperature of the boiler feed water rises
a. 1, 2, 3
b. 2, 3
c. 1, 3
d. 4
e. 1, 4
A
a. 1, 2, 3
15
Q
- Which of the following has a rising steam temperature characteristic?
a. Radiant superheater
b. Pendent superheater
c. Horizontal superheater
d. Convection superheater
e. Separately fired superheater
A
d. Convection superheater
16
Q
- Which of the following has a falling steam temperature characteristic?
a. Radiant superheater
b. Pendent superheater
c. Horizontal superheater
d. Convection superheater
e. Separately fired superheater
A
a. Radiant superheater
17
Q
- Which of the following apply to the combination of a radiant superheater and a convection heater?
1) Frequently steam-generating units have a convection superheater in series with a radiant superheater
2) The steam enters the radiant superheater first and then the convection superheater
3) A fairly steady steam temperature characteristic is produced
4) Superheated steam temperatures remain fairly constant at all boiler loads
a. 1, 3, 4
b. 1, 2, 3, 4
c. 1, 2, 3
d. 2, 3
e. 2, 3, 4
A
b. 1, 2, 3, 4
18
Q
- Which of the following correctly describes the manner in which pendent superheaters are suspended?
a. Horizontal
b. Inclined at an angle of 60°
c. Vertical
d. Inclined at an angle of 45°
e. Inclined at an angle of 30°
A
c. Vertical
19
Q
- A convection superheater:
a. Has the combustion air passing across it
b. Is always located in the radiant furnace zone
c. Has the hot combustion gases passing over it
d. Is located after the economizer
e. Is indirect contact with the flame
A
c. Has the hot combustion gases passing over it
20
Q
- A primary superheater:
a. Has the hottest gases passing across it
b. Is always located in the radiant furnace zone
c. Is the most important superheater
d. Receives the saturated steam from the steam drum
e. Is always located in the convection zone
A
d. Receives the saturated steam from the steam drum
21
Q
- Superheated steam:
a. Can be produced in the saturated steam drum of a water tube boiler
b. Has a temperature that is higher than the saturation temperature for that pressure
c. Is almost dry and contains very little moisture
d. Cannot be used for soot blowers
e. May cause erosion of turbine blades
A
b. Has a temperature that is higher than the saturation temperature for that pressure
22
Q
- Which of the following are types of superheaters:
1) Primary
2) Secondary
3) Conduction
4) Radiant
5) Convection
6) Pendant
7) Attemperator
a. 1, 2, 3, 4
b. 1, 2, 4, 5, 6
c. 1, 3, 4, 5, 7
d. 3, 4, 5, 6, 7
e. 1, 2, 3, 6, 7
A
b. 1, 2, 4, 5, 6
23
Q
- Steam flow from the steam drum is fed to secondary superheater first and then to primary superheater.
a. True
b. False
A
b. False
24
Q
- Which of the following are disadvantages in separately fired superheaters?
1) Provides a wider range of temperature control
2) Higher initial cost
3) Lower operating efficiency
4) Larger space requirement
a. 1, 2
b. 1, 2, 3
c. 2, 3, 4
d. 3, 4
e. 1, 4
A
c. 2, 3, 4
25
286. The separately fired superheater is located in a _______ apart from the main steam generator and is independent of the steam generator operating conditions.
a. boiler
b. furnace
c. building
d. enclosure
b. furnace
26
287. The reheater receives steam, which has already expanded through a portion of the turbine, and as a result of this expansion has dropped in pressure and in _________.
a. quality
b. volume
c. temperature
d. energy
c. temperature
27
288. In the reheater, the steam has its temperature raised to about the same temperature as was initially provided by the _________.
a. turbine
b. boiler
c. feedwater
d. superheater
d. superheater
28
289. Reheaters are located in the furnace in areas of relatively _____ gas temperatures.
a. high
b. low
c. moderate
d. average
a. high
29
290. The temperature control methods used for reheater temperature control are the same as those used for __________ temperature control.
a. boiler
b. fuel gas
c. superheater
d. preheater
c. superheater
30
291. The steam flow passes through the reheater immediately after the superheater.
a. True
b. False
b. False
31
292. The two basic types of economizers are:
a. Radiant and convection
b. Integral and sensible
c. Sensible and radiant
d. Integral and separate
e. Recuperative and regenerative
d. Integral and separate
32
293. An economizer transfers sensible heat to the feedwater before the feedwater is mixed with the circulating boiler water.
a. True
b. False
a. True
33
294. An economizer is:
1) An energy saving device
2) A boiler feedwater preheater
3) A device that has water inside tubes and hot gases on the outside
4) A device normally located behind the air preheater
a. 1, 2, 3, 4
b. 1, 4
c. 1, 3, 4
d. 2, 3, 4
e. 1, 2, 3
e. 1, 2, 3
34
295. Which of the following are classifications of economizers?
1) Gas type
2) Integral type
3) Vertical type
4) Separate type
a. 1, 3
b. 2, 4
c. 1, 2
d. 3, 4
e. 1, 4
b. 2, 4
35
296. Which of the following types of economizers is the most commonly used?
a. Horizontal type
b. Integral type
c. Vertical type
d. Separate type
e. Gas type
d. Separate type
36
297. Which of the following tube types are used on economizers?
1) Extended surface tubes
2) U bend tubes
3) Continuous tube
4) Fin tube
a. 1, 2
b. 2, 3
c. 2, 3, 4
d. 1, 2, 3, 4
e. 1, 3
d. 1, 2, 3, 4
37
298. What is the main purpose of the cast iron fins on the economizer tubes?
a. Added strength
b. To prevent corrosion
c. Increase heat transfer
d. None of the above
e. To allow hot gases to make more than one pass through a boiler
c. Increase heat transfer
38
299. What is the purpose of the handholes on certain economizers?
1) Used for extra strength
2) Used for installation
3) Used for repair
4) Used for inspection
a. 2, 3, 4
b. 1, 2, 3
c. 2, 3
d. 1, 2, 3, 4
e. 1, 3, 4
a. 2, 3, 4
39
300. Which of the following are advantages of an economizer?
1) Not as much boiler feedwater is required
2) There is less thermal shock to the boiler drum
3) There is not as great a pressure drop through the unit
4) There is an increase in boiler efficiency
a. 1, 3
b. 2, 4
c. 1, 2, 3
d. 2, 3, 4
e. 1, 3, 4
b. 2, 4
40
301. Which of the following are disadvantages of economizers?
1) There is more thermal shock
2) There is increased fan power
3) Surfaces must be kept clean to provide increased efficiency
4) More fuel is needed if the boiler has an economizer
a. 1, 2
b. 2, 3
c. 3, 4
d. 2, 3, 4
e. 1, 4
b. 2, 3
41
302. Which of the following types of boilers use economizers?
1) Water tube boiler
2) Fire tube boiler
3) Electric boiler
4) Waste heat boiler
a. 1, 3
b. 2, 4
c. 2, 3, 4
d. 1, 2, 4
e. 3, 4
d. 1, 2, 4
42
303. Which of the following statements apply to air heaters?
1) This is another method of recovering heat from the flue gases
2) They are often called air preheaters
3) They consist of a heat exchanger surface located in the path of the
combustion gases
4) Combustion efficiency is improved
a. 1, 2
b. 2, 3
c. 1, 3, 4
d. 1, 2, 3, 4
e. 1, 2, 3
d. 1, 2, 3, 4
43
304. Which of the following are classes of air heaters?
1) Pendent type
2) Recuperative type
3) Horizontal type
4) Regenerative type
a. 1, 3
b. 2, 4
c. 1, 2
d. 3, 4
e. 2, 3
b. 2, 4
44
305. Which of the following refers to recuperative air heaters?
1) They are rotary heaters
2) The heat from the flue gases passes through a plate or a tube wall to
the air on the other side
3) They are plate type air heaters
4) They are tubular air heaters
a. 1, 2
b. 1, 4
c. 2, 3, 4
d. 2, 3
e. 1, 3
c. 2, 3, 4
45
306. What is meant by "counter flow" when referring to air heaters?
a. The flue gas and the air pass through alternate passages in opposite directions.
b. The flue gas and air pass through alternate passages in the same direction.
c. The flue gas and air pass through the same passages in the same direction.
d. The flue gas flows through a by pass around the air heater.
e. The flue gas and air pass through the same passages in opposite directions.
a. The flue gas and the air pass through alternate passages in opposite directions.
46
307. The main purpose of the baffles in the tubular air heaters are:
a. To increase the strength of the heater
b. To help prevent corrosion in the heater
c. To act as a restriction for the air flow
d. To direct the air across the tubes in a number of passes
e. To help prevent erosion in the heater
d. To direct the air across the tubes in a number of passes
47
308. Which of the following statements refers to regenerative air heaters?
1) They are stationary type heaters
2) They are rotary type heaters
3) Leakage of gas and air is largely prevented by means of radial and circumferential seals
4) They may be arranged in either a vertical or a horizontal manner
a. 1, 3, 4
b. 1, 4
c. 2, 3, 4
d. 3, 4
e. 1, 2, 3
c. 2, 3, 4
48
309. Which of the following are advantages of air heaters?
1) They have a low initial cost
2) They increase the efficiency of the boiler
3) They are easily maintained
4) There is increased combustion efficiency
a. 1, 3
b. 1, 2
c. 2, 4
d. 3, 4
e. 2, 3
c. 2, 4
49
310. Which of the following could contribute to air heater corrosion?
1) If the fuel contains sulphur compounds
2) If the output of the air heater is too hot
3) If the output of the air heater approaches the dew point
4) None of the above
a. 1, 3
b. 1, 2
c. 2
d. 4
e. 1, 4
a. 1, 3
50
311. The two basic types of air preheaters are:
a. Recuperative and regenerative
b. Recuperative and radiant
c. Convection and radiant
d. Plate and tube
e. Convection and regenerative
a. Recuperative and regenerative
51
312. Hot spots on tubes not caused by slag are a more serious problem. They indicate poor heat _______ through the tube walls.
a. distribution
b. transfer
c. flux
d. sensor
b. transfer
52
313. Wet tubes on startup of the boiler are a _______ occurrence, caused by condensation on the tube walls.
a. abnormal
b. emergency
c. normal
d. flooding
c. normal
53
314. When starting up a boiler, a steam flow is needed through the __________ tubes for cooling.
a. superheater
b. preheater
c. boiler
d. turbine
a. superheater
54
315. There is no steam flow through the ______ tubes before the steam turbine has a steam flow through it. Be careful not to increase boiler firing too rapidly and overheat the reheat tubes, during startup.
a. superheater
b. economizer
c. reheater
d. boiler
c. reheater
55
316. When starting the boiler, it may be necessary to keep a flow of BFW through the _________ tubes to prevent overheating and fouling.
a. superheater
b. economizer
c. reheater
d. boiler
b. economizer
56
317. The temperatures of the flue gas leaving the preheater must be kept above the _______ to avoid condensation.
a. flash point
b. melt point
c. dewpoint
d. ambient
c. dewpoint
57
318. When the boiler is shut down, the air preheater should be inspected for signs of _______.
a. wear
b. distortion
c. overheating
d. corrosion
d. corrosion
58
319. The water ________ of the economizer exit is always below that of the steam drum to prevent steaming in the economizer.
a. temperature
b. pressure
c. flow
d. quality
a. temperature
59
320. The water and water/steam mixture in the steam generation tubes is at _________ temperature.
a. superheat
b. critical
c. saturation
d. normal
c. saturation
60
321. The _____ increases the temperature of the steam from the H.P. turbine back up to superheat temperature.
a. superheater
b. economizer
c. furnace
d. reheater
d. reheater
