ABSA 3B1 Complete Exam Study
Questions with Expert Graded A+
Answers | Guarantee Pass!
1. What is the steam capacity range of a packaged water tube boiler? -
ANSWER 2,300 kg/h to 65,000 kg/h
2. What is the typical maximum pressure of a packaged water tube boiler? -
ANSWER Up to 1,700 kPa, reaching over 6,200 kPa in some cases
3. Where does steam separation occur in a water tube boiler? - ANSWER In
the steam drum, where steam separation equipment is located.
4. Why are A, D, and O type boilers called integral furnace boilers? -
ANSWER Because their furnaces are cooled by water tubes that line the
furnace walls.
5. What is the drum arrangement of an A-type boiler? - ANSWER One steam
drum centered above two mud drums, forming an A shape.
6. In an A-type boiler, where does the majority of steam production occur? -
ANSWER In the central furnace wall tubes.
7. What is a major advantage of the D-type boiler design? - ANSWER
Superheaters and economizers can be added to the radiant or convection
zone with relative ease.
,8. What is the primary function of screen tubes in a boiler? - ANSWER To
absorb remaining radiant heat and protect the superheater tubes.
9. Which boiler design exposes the least amount of tube surface to radiant
heat? - ANSWER The O-type boiler.
10.What is the typical path of flue gases in A, D, or O type boilers? -
ANSWER Burners fire at one end, gases travel to the far end, turn back
through the generating bank in multiple passes, then exit to the economizer.
11.What is the purpose of a reheater in a steam generating unit? - ANSWER
To return steam from the turbine LP stage back to superheated temperature.
12.To what temperature is feedwater heated in the economizer? - ANSWER To
within 20°C of the boiler water temperature.
13.What is the purpose of an air preheater? - ANSWER To preheat combustion
air using outgoing flue gas to increase heat recovery and combustion
efficiency.
14.What are the typical output capacities of the largest steam generating units? -
ANSWER Over 3,000,000 kg/h at 17,900 kPa, superheated to 538°C.
15.At what pressure does the density difference between water and steam
become zero? - ANSWER 22,090 kPa
16.What defines a supercritical boiler? - ANSWER A boiler that operates
above the critical pressure of 22,090 kPa.
,17.How are boilers classified when operating below critical pressure? -
ANSWER Subcritical boilers
18.Why can a supercritical boiler not use natural circulation? - ANSWER
Above critical pressure, the densities of water and steam are equal, which
eliminates the density difference required to drive natural circulation.
19.What is a defining structural feature of supercritical boilers? - ANSWER
They do not have a steam drum.
20.What happens to water in a supercritical boiler instead of boiling? -
ANSWER It transforms directly into vapour with no two-phase flow.
21.Why is the capacity of a packaged watertube boiler varied by changing its
length? - ANSWER Because height and width are standardized to meet
transport and road restrictions.
22.What is the primary advantage of packaged watertube boilers? - ANSWER
Low cost due to factory assembly and reduced shipping costs.
23.How do packaged watertube boilers supply combustion air? - ANSWER
Through a forced draft (FD) fan.
24.What is the main distinction between a shop-assembled boiler and a
packaged boiler? - ANSWER Shop-assembled boilers are built to exact
purchaser specifications and cannot be ordered off the shelf.
25.Which sections of a shop-assembled boiler are typically assembled in the
shop? - ANSWER The furnace section including tubes, drum, and headers.
, 26.What is the typical minimum output of a field-erected boiler? - ANSWER
150,000 kg/h or more.
27.What components are assembled on-site for a field-erected boiler? -
ANSWER Support structures, furnace tubes, ductwork, burners, fans, drums,
refractory, insulation, and casing.
28.What is the rating equivalency for boiler heating surface area? - ANSWER
1 m² = 10 kW.
29.When electric power is the heating source, how is a boiler rated? -
ANSWER By the maximum kilowatt rating of the heating element.
30.When neither standard heating surface nor electric rating methods apply,
what is the equivalency used? - ANSWER An hourly boiler output of 36 MJ
is equivalent to 10 kW.
31.Which surface radius is used when computing the area of a curved heating
surface? - ANSWER The surface with the greater radius.
32.When a boiler supplies its entire steam output to a turbine generator, how is
its output often expressed? - ANSWER In terms of the power output of the
generator.
33.What are the two categories of tubes in a watertube boiler circulation
system? - ANSWER Downcomers and risers.
Questions with Expert Graded A+
Answers | Guarantee Pass!
1. What is the steam capacity range of a packaged water tube boiler? -
ANSWER 2,300 kg/h to 65,000 kg/h
2. What is the typical maximum pressure of a packaged water tube boiler? -
ANSWER Up to 1,700 kPa, reaching over 6,200 kPa in some cases
3. Where does steam separation occur in a water tube boiler? - ANSWER In
the steam drum, where steam separation equipment is located.
4. Why are A, D, and O type boilers called integral furnace boilers? -
ANSWER Because their furnaces are cooled by water tubes that line the
furnace walls.
5. What is the drum arrangement of an A-type boiler? - ANSWER One steam
drum centered above two mud drums, forming an A shape.
6. In an A-type boiler, where does the majority of steam production occur? -
ANSWER In the central furnace wall tubes.
7. What is a major advantage of the D-type boiler design? - ANSWER
Superheaters and economizers can be added to the radiant or convection
zone with relative ease.
,8. What is the primary function of screen tubes in a boiler? - ANSWER To
absorb remaining radiant heat and protect the superheater tubes.
9. Which boiler design exposes the least amount of tube surface to radiant
heat? - ANSWER The O-type boiler.
10.What is the typical path of flue gases in A, D, or O type boilers? -
ANSWER Burners fire at one end, gases travel to the far end, turn back
through the generating bank in multiple passes, then exit to the economizer.
11.What is the purpose of a reheater in a steam generating unit? - ANSWER
To return steam from the turbine LP stage back to superheated temperature.
12.To what temperature is feedwater heated in the economizer? - ANSWER To
within 20°C of the boiler water temperature.
13.What is the purpose of an air preheater? - ANSWER To preheat combustion
air using outgoing flue gas to increase heat recovery and combustion
efficiency.
14.What are the typical output capacities of the largest steam generating units? -
ANSWER Over 3,000,000 kg/h at 17,900 kPa, superheated to 538°C.
15.At what pressure does the density difference between water and steam
become zero? - ANSWER 22,090 kPa
16.What defines a supercritical boiler? - ANSWER A boiler that operates
above the critical pressure of 22,090 kPa.
,17.How are boilers classified when operating below critical pressure? -
ANSWER Subcritical boilers
18.Why can a supercritical boiler not use natural circulation? - ANSWER
Above critical pressure, the densities of water and steam are equal, which
eliminates the density difference required to drive natural circulation.
19.What is a defining structural feature of supercritical boilers? - ANSWER
They do not have a steam drum.
20.What happens to water in a supercritical boiler instead of boiling? -
ANSWER It transforms directly into vapour with no two-phase flow.
21.Why is the capacity of a packaged watertube boiler varied by changing its
length? - ANSWER Because height and width are standardized to meet
transport and road restrictions.
22.What is the primary advantage of packaged watertube boilers? - ANSWER
Low cost due to factory assembly and reduced shipping costs.
23.How do packaged watertube boilers supply combustion air? - ANSWER
Through a forced draft (FD) fan.
24.What is the main distinction between a shop-assembled boiler and a
packaged boiler? - ANSWER Shop-assembled boilers are built to exact
purchaser specifications and cannot be ordered off the shelf.
25.Which sections of a shop-assembled boiler are typically assembled in the
shop? - ANSWER The furnace section including tubes, drum, and headers.
, 26.What is the typical minimum output of a field-erected boiler? - ANSWER
150,000 kg/h or more.
27.What components are assembled on-site for a field-erected boiler? -
ANSWER Support structures, furnace tubes, ductwork, burners, fans, drums,
refractory, insulation, and casing.
28.What is the rating equivalency for boiler heating surface area? - ANSWER
1 m² = 10 kW.
29.When electric power is the heating source, how is a boiler rated? -
ANSWER By the maximum kilowatt rating of the heating element.
30.When neither standard heating surface nor electric rating methods apply,
what is the equivalency used? - ANSWER An hourly boiler output of 36 MJ
is equivalent to 10 kW.
31.Which surface radius is used when computing the area of a curved heating
surface? - ANSWER The surface with the greater radius.
32.When a boiler supplies its entire steam output to a turbine generator, how is
its output often expressed? - ANSWER In terms of the power output of the
generator.
33.What are the two categories of tubes in a watertube boiler circulation
system? - ANSWER Downcomers and risers.
