Boiler Draft Equipment Flashcards
A way of increasing natural draft is to
a) incorporate a forced draft fan
b) have the outside air temperature increase
c) install an induced draft fan
d) increase stack height
e) decrease the amount of excess air
d) increase stack height
When draft is produced by natural means,
a) hot air surrounding the boiler increases draft
b) fans can control the flue gas flow
c) a short stack will increase draft
d) the diameter of the stack will improve the draft
e) cooler air surrounding the boiler increases draft
e) cooler air surrounding the boiler increases draft
Primary air a) is supplied in the combustion zone b) is the same as excess air c) is supplied on all types of burners d) is pre-mixed with the fuel before being admitted to the furnace e) enters the furnace before the fuel
d) is pre-mixed with the fuel before being admitted to the
furnace
A more durable chimney for power plant application is the
a) brick chimney
b) reinforced concrete chimney
c) steel chimney
d) insulated steel chimney
e) guy wire supported chimney
b) reinforced concrete chimney
Chimneys are commonly lined with
a) concrete
b) common brick
c) clay
d) mortar
e) insulation
c) clay
The advantage of a steel stack over a reinforced concrete
stack is that a steel stack
a) is more durable
b) requires less maintenance
c) is a lower cost
d) has a longer life
e) is more resistant to abrasive flue gases
c) is a lower cost
Relative to draft, a steam jet is very popular
a) on railway steam locomotives
b) as a fuel atomizer
c) as a forced draft unit
d) for increasing furnace pressure
e) for decreasing draft during cold weather
a) on railway steam locomotives
What are the advantages of mechanical draft?
- dependent on atmospheric air temperatures
- independent of the chimney temperature
- better draft regulation
- can be regulated accurately
a) 1, 2, 3, 4
b) 1, 2, 3
c) 1, 3, 4
d) 2, 3, 4
e) 3, 4
d) 2, 3, 4
In a balanced draft system the air heater is placed:
- between ID fan and stack
- between ID fan and boiler
- between forced draft fan and boiler
- on inlet ducting to forced draft fan
a) 1, 2, 3
b) 2, 3, 4
c) 2, 3
d) 1, 4
e) 1, 3, 4
c) 2, 3
The most efficient operation of a fan demands that
a) the speed be only sufficient enough to supply the required
amount of air
b) inlet damper controls are used
c) outlet damper controls are used
d) constant speed electric motors are used
e) gaseous fuels be fired
a) the speed be only sufficient enough to supply the required
amount of air
Balanced draft
a) means furnace pressure is maintained at some desired
value
b) means air flow is always constant
c) requires an FD and ID fan, never just an FD fan
d) can be accomplished with just a chimney
e) means air and fuel quantities are the same per unit time
a) means furnace pressure is maintained at some desired
value
An induced draft fan
a) is physically smaller than a forced draft fan
b) has less expensive materials of construction than an FD
fan
c) handles only air
d) discharges air to the windbox
e) operates at much higher temperatures than an FD fan
e) operates at much higher temperatures than an FD fan
A pressurized furnace is usually associated with
a) balanced draft
b) induced draft
c) natural draft
d) packaged boilers with FD
e) large steam generators
d) packaged boilers with FD
Induced draft may be accomplished by a:
- steam jet
- fan
- windbox
- forced draft fan
a) 1, 2
b) 2, 3, 4
c) 2, 4
d) 2, 3
e) 3, 4
a) 1, 2
In a balanced draft system, the forced draft fan is
a) larger than the induced draft fan
b) the same size as the induced draft fan
c) smaller than the induced draft fan
d) designed to handle hot combustion gases
e) subjected to the products of combustion and high temperatures
c) smaller than the induced draft fan