ABSA 4A UNIT 12 QUESTIONS SOLVED 2025
A draft system with a FD and ID fan is ___________
Select one:
a. Forced
b. Balanced
c. Induced
d. Hybrid - ANSWER-b. Balanced
A float operated level control:
Select one:
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 - ANSWER-c. Is only used on small boilers
A sudden drop in steam pressure causes
Select one:
a. a sudden increase in drum level
b. a rapid collapse of steam bubbles in the boiler
c. "shrinkage"
d. a single element feedwater control to immediately add water to the drum - ANSWER-
a. a sudden increase in drum level
An induced draft fan handles:
Select one:
a. Air from the combustion chamber
b. Air going to the combustion chamber
c. Flue gases going to the combustion chamber
d. Flue gases from the combustion chamber - ANSWER-d. Flue gases from the
combustion chamber
Boiler chimneys are commonly lined with:
Select one:
a. Concrete
b. Rubber
c. Fire brick
d. Insulation - ANSWER-c. Fire brick
, Boiler combustion is regulated by:
Select one:
a. Varying the speed of an ID fan
b. Controlling or regulating the fuel flow
c. Varying the speed of an FD fan
d. Controlling the air and fuel flow - ANSWER-d. Controlling the air and fuel flow
Carbon that is not combined with hydrogen is referred to as:
Select one:
a. Mono-carbon
b. Separated carbon
c. Free carbon
d. Fixed carbon - ANSWER-d. Fixed carbon
Combustion of fuel in a boiler furnace:
Select one:
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 - ANSWER-b. Should occur with a minimum of excess air
Dissolved oxygen in condensate:
Select one:
a. Will cause waterside corrosion
b. Can cause scaling on the return lines
c. Is removed with amines
d. Necessitates the installation of a deaerator - ANSWER-a. Will cause waterside
corrosion
During combustion in a boiler furnace, black smoke may be caused by:
Select one:
a .Insufficient combustion air
b. Flyash in the flue gas
c. Too much nitrogen in the air
d. Too much combustion air - ANSWER-a. Insufficient combustion air
Fluidized bed boilers can successfully burn coal with ash contents as high as
Select one:
a.30%
b.55%
A draft system with a FD and ID fan is ___________
Select one:
a. Forced
b. Balanced
c. Induced
d. Hybrid - ANSWER-b. Balanced
A float operated level control:
Select one:
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 - ANSWER-c. Is only used on small boilers
A sudden drop in steam pressure causes
Select one:
a. a sudden increase in drum level
b. a rapid collapse of steam bubbles in the boiler
c. "shrinkage"
d. a single element feedwater control to immediately add water to the drum - ANSWER-
a. a sudden increase in drum level
An induced draft fan handles:
Select one:
a. Air from the combustion chamber
b. Air going to the combustion chamber
c. Flue gases going to the combustion chamber
d. Flue gases from the combustion chamber - ANSWER-d. Flue gases from the
combustion chamber
Boiler chimneys are commonly lined with:
Select one:
a. Concrete
b. Rubber
c. Fire brick
d. Insulation - ANSWER-c. Fire brick
, Boiler combustion is regulated by:
Select one:
a. Varying the speed of an ID fan
b. Controlling or regulating the fuel flow
c. Varying the speed of an FD fan
d. Controlling the air and fuel flow - ANSWER-d. Controlling the air and fuel flow
Carbon that is not combined with hydrogen is referred to as:
Select one:
a. Mono-carbon
b. Separated carbon
c. Free carbon
d. Fixed carbon - ANSWER-d. Fixed carbon
Combustion of fuel in a boiler furnace:
Select one:
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 - ANSWER-b. Should occur with a minimum of excess air
Dissolved oxygen in condensate:
Select one:
a. Will cause waterside corrosion
b. Can cause scaling on the return lines
c. Is removed with amines
d. Necessitates the installation of a deaerator - ANSWER-a. Will cause waterside
corrosion
During combustion in a boiler furnace, black smoke may be caused by:
Select one:
a .Insufficient combustion air
b. Flyash in the flue gas
c. Too much nitrogen in the air
d. Too much combustion air - ANSWER-a. Insufficient combustion air
Fluidized bed boilers can successfully burn coal with ash contents as high as
Select one:
a.30%
b.55%
