3B1 ABSA Questions with Complete
Solutions (Latest 2025)
Combustion air for the burners is preheated to ______ in the
air heater section by combustion gases leaving the
economizer section. - Correct Answers ✅350°C
Most downcomers run horizontally between the steam drum
and the mud drum. - Correct Answers ✅False
Steam bubbles form in the hottest tubes and rise to the
steam drum where the steam is separated out of the water
and steam mixture. Circulation is maintained by water
returning to the mud drum through the cooler tubes. The
hotter tubes (the risers) are the ones in the radiant area of
the furnace and the hottest areas of the generating bank of
tubes. - Correct Answers ✅True
What is the main advantage of the packaged boiler? -
Correct Answers ✅Low cost
Generally, two types of draft fans are used. A(n) _____ ____
fan supplies air to the air preheater. The preheated air for
combustion goes to the coal pulverizers and to the burners.
A(n) ______ ____ fan exhausts the combustion gases from the
air heater to the stack. - Correct Answers ✅Forced draft,
induced draft
One square metre of heating surface equals 10 kilowatts. The
heating surface of a boiler must be determined by computing
,3B1 ABSA Questions with Complete
Solutions (Latest 2025)
the area of the surface involved in square metres. Where a
computation is to be made of a curved surface, the surface
with the greater radius is taken. - Correct Answers ✅True
When the boiler provides the entire steam supply to an
electric generating unit, the output of the boiler is expressed
in terms of power output of the generator (e.g. a 300
megawatt boiler). - Correct Answers ✅True
What is the range for packaged watertube boiler capacities? -
Correct Answers ✅2300 kg to 65 000 kg per hour
What is the output of field-erected boilers? - Correct
Answers ✅150 000 kg/h or more
The A-, D-, and O- type boilers have furnaces cooled by
_________ lining the furnace walls. - Correct Answers
✅Watertubes
Where electric power is used as the heating source, the boiler
rating is the maximum kilowatt rating of which aspect? -
Correct Answers ✅Heating element
The difference in density between water and saturated steam
becomes progressively less with increased pressure and
disappears altogether at the critical pressure of _______ . -
Correct Answers ✅22 090 kPa
,3B1 ABSA Questions with Complete
Solutions (Latest 2025)
The main feature of a controlled circulation boiler is a
(circulating) pump, which is used to provide circulation. -
Correct Answers ✅True
The advantage of forced circulation in a boiler is a _________
flow in all tubes. - Correct Answers ✅Positive
The steam separating equipment separates the _______ from
the steam/water mixture. - Correct Answers ✅Steam
Not all once-through boilers use forced circulation. - Correct
Answers ✅False
The arrangement of a once-through boiler has no drums. How
many passes through the unit does it take to heat, evaporate,
and superheat the feedwater? - Correct Answers ✅One
passage
Steam generators operating above critical pressure are said
to be ______-critical, and steam generators operating below
critical pressure are classed as ____-critical. - Correct
Answers ✅Super, sub
A steam generating unit consists of a number of elements, all
of which contribute to the production of steam. Which of the
, 3B1 ABSA Questions with Complete
Solutions (Latest 2025)
following is not an element of a typical steam generator? -
Correct Answers ✅Water conditioner
Natural circulation in a boiler depends on the ___________ in
the density of a column of water and the density of a column
that contains a steam/water mixture. - Correct Answers
✅Difference
Feedwater entering the boiler section first passes through the
__________ section where it is heated by the combustion gases
leaving the boiler. - Correct Answers ✅Economizer
The disadvantages of forced circulation in a boiler are the
__________ of equipment such as pumps and piping - Correct
Answers ✅Increased costs
There are several factors that influence the natural circulation
in a watertube boiler. Which of the following is NOT one of
those factors? - Correct Answers ✅The diameter of the
steam drum.
The downcomers are located in the ______ regions of the
boiler, or external to the furnace altogether. The risers are
located in the ________ zones of the boiler, and are exposed to
radiant heat of the furnace or to the very hot flue gases near
the furnace. - Correct Answers ✅Cooler, hottest
Solutions (Latest 2025)
Combustion air for the burners is preheated to ______ in the
air heater section by combustion gases leaving the
economizer section. - Correct Answers ✅350°C
Most downcomers run horizontally between the steam drum
and the mud drum. - Correct Answers ✅False
Steam bubbles form in the hottest tubes and rise to the
steam drum where the steam is separated out of the water
and steam mixture. Circulation is maintained by water
returning to the mud drum through the cooler tubes. The
hotter tubes (the risers) are the ones in the radiant area of
the furnace and the hottest areas of the generating bank of
tubes. - Correct Answers ✅True
What is the main advantage of the packaged boiler? -
Correct Answers ✅Low cost
Generally, two types of draft fans are used. A(n) _____ ____
fan supplies air to the air preheater. The preheated air for
combustion goes to the coal pulverizers and to the burners.
A(n) ______ ____ fan exhausts the combustion gases from the
air heater to the stack. - Correct Answers ✅Forced draft,
induced draft
One square metre of heating surface equals 10 kilowatts. The
heating surface of a boiler must be determined by computing
,3B1 ABSA Questions with Complete
Solutions (Latest 2025)
the area of the surface involved in square metres. Where a
computation is to be made of a curved surface, the surface
with the greater radius is taken. - Correct Answers ✅True
When the boiler provides the entire steam supply to an
electric generating unit, the output of the boiler is expressed
in terms of power output of the generator (e.g. a 300
megawatt boiler). - Correct Answers ✅True
What is the range for packaged watertube boiler capacities? -
Correct Answers ✅2300 kg to 65 000 kg per hour
What is the output of field-erected boilers? - Correct
Answers ✅150 000 kg/h or more
The A-, D-, and O- type boilers have furnaces cooled by
_________ lining the furnace walls. - Correct Answers
✅Watertubes
Where electric power is used as the heating source, the boiler
rating is the maximum kilowatt rating of which aspect? -
Correct Answers ✅Heating element
The difference in density between water and saturated steam
becomes progressively less with increased pressure and
disappears altogether at the critical pressure of _______ . -
Correct Answers ✅22 090 kPa
,3B1 ABSA Questions with Complete
Solutions (Latest 2025)
The main feature of a controlled circulation boiler is a
(circulating) pump, which is used to provide circulation. -
Correct Answers ✅True
The advantage of forced circulation in a boiler is a _________
flow in all tubes. - Correct Answers ✅Positive
The steam separating equipment separates the _______ from
the steam/water mixture. - Correct Answers ✅Steam
Not all once-through boilers use forced circulation. - Correct
Answers ✅False
The arrangement of a once-through boiler has no drums. How
many passes through the unit does it take to heat, evaporate,
and superheat the feedwater? - Correct Answers ✅One
passage
Steam generators operating above critical pressure are said
to be ______-critical, and steam generators operating below
critical pressure are classed as ____-critical. - Correct
Answers ✅Super, sub
A steam generating unit consists of a number of elements, all
of which contribute to the production of steam. Which of the
, 3B1 ABSA Questions with Complete
Solutions (Latest 2025)
following is not an element of a typical steam generator? -
Correct Answers ✅Water conditioner
Natural circulation in a boiler depends on the ___________ in
the density of a column of water and the density of a column
that contains a steam/water mixture. - Correct Answers
✅Difference
Feedwater entering the boiler section first passes through the
__________ section where it is heated by the combustion gases
leaving the boiler. - Correct Answers ✅Economizer
The disadvantages of forced circulation in a boiler are the
__________ of equipment such as pumps and piping - Correct
Answers ✅Increased costs
There are several factors that influence the natural circulation
in a watertube boiler. Which of the following is NOT one of
those factors? - Correct Answers ✅The diameter of the
steam drum.
The downcomers are located in the ______ regions of the
boiler, or external to the furnace altogether. The risers are
located in the ________ zones of the boiler, and are exposed to
radiant heat of the furnace or to the very hot flue gases near
the furnace. - Correct Answers ✅Cooler, hottest
