4A Power Engineering - Unit 11: Introduction to Boiler Designs

Air heaters are implemented in steam generating units in order to:

Select one:

a. Produce dryer steam

b. Prevent utility boilers from freezing during winter outages

c. Improve combustion efficiency

d. Keep the boiler house warm

C

Large steam generators:

Select one:

a. Are of the water tube type

b. Have poor water circulation

c. Are fired by pulverized coal only

d. Are bottom supported

A

The amount of current passed through the water of an electrode boiler depends on the:

Select one:

a. Voltage setting of the pressure control

b. Control valve setting

c. Speed of the circulating pump

d. Depth of the electrodes in the water

D

Boiler stays:

Select one:

a. Are used to support flat surfaces in a boiler

b. Are mostly used in watertube boilers

c. Have to be replaced every two years

d. Secure a boiler to its foundation

A

One type of electrode boiler depends on the electrodes being submerged in water in order to generate steam.What safety device is not required on this type of electric boiler?

Select one:

a. Low water cut-off

b. Blow-off valve

c. Gauge glass

d. Safety valve

A

A pressure gauge on a section IV boiler:

Select one:

a. Graduated to between 1.5 and 2 times the PRV setting

b. graduated to no less than 30 psi (200 kPa), nor more than 60 psi (414 kPa)

c. graduated to a maximum setting or double the MAWP

d. Graduated to a maximum setting of double the PRV setting

B

Power Engineers are required (usually) to operate:

Select one:

a. Section I boilers over 750 kW, and section IV boilers over 1000 kW

b. Section I boilers of all sizes, and section IV steam boilers over 20 kW, and no section IV hot water boilers

c. Section I boilers of all sizes, and all steam section IV boilers, but not section IV hot water boilers

d. Section I boilers over 20 kW, and section IV boilers over 750 kW

D

The steam space of a boiler must be large enough to:

Select one:

a. Accommodate all the steam riser tubes

b. allow the steam to rise from the surface of the water

c. Reduce the cooling effect of water

d. Keep the steam pressure down

B

Tubes for high pressure service are usually:

Select one:

a. Resistance welded construction

b. Seamless construction

c. Lap welded construction

d. Fin-tube designs

B

A high-pressure steam boiler is one in which steam is generated at a pressure greater than:

Select one:

a. 76.4 kPa

b. 51.2 kPa

c. 101.3 kPa

d. 100 kPa

D

With regard to a steam boiler, the term "HRT" means:

Select one:

a. Horizontal receiver tubes

b. Horizontal return tubular

c. Hot return tubes

d. Highly regulated temperature

B

The copper tube tubular heating boiler:

Select one:

a. Is highly susceptible to corrosion

b. Has the furnace in the upper section

c. Generates high pressure steam

d. Are mostly gas fired

D

The boiler term "drum" commonly refers to the pressure container of a watertube boiler, whereas the term "_____" commonly refers to the pressure vessel of a firetube boiler

Select one:

a. Cylinder

b. Shell

c. Tank

d. Vessel

B

A corrugated furnace gives required strength with thinner metal, increases heating surface and:

Select one:

a. Decreases combustion turbulence

b. Allows for differential expansion and contraction

c. Adds to the overall material cost of the unit

d. Increases the boiler mass

B

The steam and water spaces of a cast iron sectional boiler are connected by:

Select one:

a. Hydraulic jacks

b. Push nipples or gaskets

c. Tie nipples

d. Tie rods

B

What type of furnace is surrounded by brickwork rather than by water?

Select one:

a. Internally fired

b. Staged combustion furnace

c. Cyclone furnace

d. Externally fired

D

The sections of a cast iron sectional boiler are held together by:

Select one:

a. Cast iron pipes

b. Steel studs

c. tie rods

d. Stay bolts

C

Heating boilers attain maximum efficiency only when they are operated:

Select one:

a. Continuously at half load

b. Continuously at full load

c. Intermittently at half load

d. Intermittently at 90% of the load

B

When part of firetube boilers, heads are commonly called what ?

Select one:

a. End plates

b. Plates

c. Tube sheets

d. Heads

C

An early shell-type boiler had ___________ as its heating surface:

Select one:

a. Two passes along the shell or drum

b. The total shell side and one end plate or head

c. The lower part of the shell and the rear plate or head

d. Only the lower part of the shell

D

The two general designs of electric boilers are the:

Select one:

a. Grounded and ungrounded

b. Electrode and immersion

c. AC and DC

d. Firetube and watertube

B

The output of an immersion type electric boiler is controlled by __________ one or more elements as required.

Select one:

a. controlling the basket level of

b. immersing

c. short-circuiting

d. turning the power on or off

D

Early watertube boilers had furnace walls constructed of brick. Modern furnaces use ____________to form the furnace walls.

Select one:

a. Block insulation

b. Plastic insulation

c. Watertubes

d. Steel casing

C

Expanding of tubes into a tube sheet is also called:

Select one:

a. Beading

b. Rolling

c. Flaring

d. Peening

B

The heating surface of a boiler consists of all parts that:

Select one:

a. Are exposed to hot gases

b. Have water on one side and hot gases on the other side

c. Have steam on one side and hot gases on the other side

d. Have water on one side and steam on the other side

B

An advantage of a vertical tubeless firetube boiler is that it requires:

Select one:

a. Very little water treatment

b. Less fuel for combustion

c. No fuel handling equipment

d. Relatively small floor space

D

An advantage of a packaged, low-pressure tubular or watertube boiler is:

Select one:

a. Safety due to the low potential energy of the water contained within them

b. Its lower initial cost

c. Its less critical water treatment requirement

d. Its ability to meet load changes due to its heat reserve

A

To maintain high velocities through all gas passes in a 4-pass firetube boiler, the cross-sectional area of each succeeding pass is:

Select one:

a. Doubled

b. Tripled

c. Increased

d. Reduced

D

Packaged boilers:

Select one:

a. Have risers and down comers

b. Must not be used over 100 kPa working pressure

c. Are completely factory-built

d. Are shipped in a packing case with the components disassembled

C

Stays are not normally required in watertube boilers because:

Select one:

a. They would block access

b. The pressure parts have no flat surfaces

c. The ASME codes only allow stays in firetube boilers

d. Space does not permit their installation

B

Cast Iron is suitable for boiler construction material up to ______kPa, and fittings to a limit of _______kPa and ________C.

Select one:

a. 1700, 1700, 230

b. 100, 120, 120

c. 100, 1700, 230

d. 70, 100, 230

C

One advantage of the low-pressure flexible watertube boiler is that:

Select one:

a. Tubes never need replacement

b. Expansion and contraction stresses are eliminated

c. No maintenance is required

d. Feedwater treatment is unnecessary

B

A firetube boiler is one that has:

Select one:

a. Water on the outside of the tubes and hot gas on the inside of the tubes

b. Water on the outside of the tubes and hot water on the inside of the tubes

c. The furnace as the first pass of the burner flame

d. Water on the inside of the tubes and hot gas on the outside

A

Tube stubs, which are used to connect fittings and attachments to drums and headers, are known as:

Select one:

a. Flanges

b. Nozzles

c. Manifolds

d. Fittings

B

The purpose of a superheater is to:

Select one:

a. Control the pressure of the steam

b. Increase the temperature of the steam

c. Increase the steam output

d. Produce high pressure steam

B

A hot water boiler is considered a high temperature water boiler when:

Select one:

a. its energy input exceeds 58.7 kW

b. its operating temperature is less than 120°C

c. its operating temperature is greater than 120°C

d. its design pressure is less than 1100 kPa

C

A reason for preferring copper tubing in a tubular boiler is:

Select one:

a. Corrosion resistance

b. Ease of replacement of the tubes

c. High metal expansion rate

d. Low cost

A

Boilers are designed with more combustion gas passes:

Select one:

a. To create less thermal stress on the boiler metal

b. So soot falls out in the last pass, leaving the first pass clear

c. To allow more time for heat transfer

d. So boiler tubes do not have to be as long

C

One advantage of cast iron boilers is:

Select one:

a. Unlimited operating pressures

b. Resistance to corrosion

c. Reduced vibration due to their heavy foundations

d. Their high factor of brittleness

B

Corrugated furnaces:

Select one:

a. Are made from rolled copper

b. Require fewer stays than plain furnaces

c. Are cheaper than plain furnaces

d. Permit expansion and contraction with reduced stress

D

In a bottom-supported boiler, the steam drum is usually:

Select one:

a. Placed between the centre line of the unit

b. Supported by piers

c. Supported by the water tubes

d. Supported by an overhead girder arrangement

C

The operating voltage for a jet-type electrode boiler may be as high as _________ kilovolts:

Select one:

a. 55

b. 25

c. 5

d. 30

B

A reason for preferring copper tubing over steel or cast iron in a tubular boiler is:

Select one:

a. Its lower cost than steel

b. Its ability to withstand high temperature

c. Because of its good ductility

d. Greater heat transfer rate

D

The furnace walls in a bent-tube watertube boiler are formed by water filled tubes, called:

Select one:

a. Waterside walls

b. Fireside walls

c. Waterwalls

d. Furnace walls

C

The windbox of a boiler is:

Select one:

a. Always maintained at a negative pressure

b. The chamber through which combustion air is introduced to the boiler furnace

c. The collector of the exhaust gases before they go into the uptake

d. Where the fuel and air are mixed for combustion

B

Beading the tube ends in a firetube boiler:

Select one:

a. stops tube leakage

b. eliminates the need to expand the tubes into the tubesheet

c. helps prevent overheating of the tube ends

d. must be followed by seal welding

C

The boiler MAWP determines:

Select one:

a. The type of PRV

b. The length of the tubes

c. The strength of the drum or shell

d. The type of burner

C

An internally fired boiler:

Select one:

a. Requires a setting

b. Has the furnace surrounded by water

c. Utilizes a high amount of refractory and/or firebrick

d. Is less efficient than an externally fired unit

B

When an air heater is used in a boiler:

Select one:

a. The boiler usually has only a forced draft fan

b. A balanced draft system cannot be used

c. It increases the efficiency of the boiler

d. The induced draft fan supplies combustion air to the air heater

C

A membrane water wall:

Select one:

a. Has waterproof membranes lining the tubes

b. Has firebrick in front of the tubes

c. Has metal plates welded between the tubes

d. Consists of a metal sheeting in front of the tubes

C

The water flow through a modular cast iron boiler system:

Select one:

a. Done without the use of headers or manifolds

b. Intermittent, occurring only while the unit is firing

c. Continuous through all modules

d. Connected in series

C

The continuous blowdown pipe on a boiler is used to:

Select one:

a. Blow chemicals into the steam drum

b. Remove concentrated dissolved solids from the boiler

c. Remove suspended matter from the boiler

d. Blow down the boiler if the pressure exceeds the maximum allowable working pressure

B

A water leg is found on a/an ____________ boiler.

Select one:

a. HRT

b. Locomotive

c. Watertube

d. Scotch

B

A packaged watertube boiler having two mud drums is the:

Select one:

a. Three drum bent-tube type

b. "A" type

c. "O" type

d. "D" type

B

Cast iron boiler capacity:<

Select one:

a. Can be increased by increasing section size

b. Cannot be increased once assembly is completed

c. Can be increased by simply adding sections

d. Is very large compared to steel boilers

C

Manholes are:

Select one:

a. Installed on all boilers

b. Provided for inspection purposes

c. Always circular in shape

d. Installed on fossil fired boilers only

B

The steam produced by an electrode type boiler depends on the:

Select one:

a. Number of electrodes energized

b. Level of water in the basket

c. Number of heating elements energized

d. Voltage supplied to the immersion elements

B

Class 1 water treatment, as per ASME section VI, is suitable for:

Select one:

a. Watertube Heating Boilers

b. Tubular heating boilers

c. Firetube Heating Boilers

d. Cast Iron boilers

D

Handhole and manhole openings:

Select one:

a. Are required on high pressure boilers only

b. Are not required on low pressure hot water boilers

c. Require a cast iron reinforcing ring

d. Permit inspection, cleaning and repairs

D

Combustion air for the burners is preheated in the _____ by hot flue gases.

Select one:

a. Windbox

b. Superheater

c. Air heater

d. Economizer

C

The Haycock boiler was:

Select one:

a. Of welded construction

b. Used around 1720

c. A return tubular design

d. A watertube design

B

Bottom Blow Off valves:

_______ on Power Boilers, and _________ on heating boilers.

Select one:

a. 1 is required, 1 is required

b. 2 are required, a drain valve only is required

c. 2 are required, 2 are required

d. 2 are required, 1 is required

D

In a low-pressure serpentine watertube boiler, the tubes are attached by either _______ or by using ferrules.

Select one:

a. Seamless fittings

b. Threading

c. Expanding

d. Welding

B

Chemicals are introduced into the boiler:

Select one:

a. by the dry pipes

b. by the internal feedwater pipe

c. in the Injection tank

d. In the mud drum

B

Surfaces that require staying in a firetube boiler are:

Select one:

a. not covered in water

b. flat

c. curved

d. ellipsoidal

B

Which of the following is a single pass boiler?

Select one:

a. HRT

b. Scotch marine

c. Packaged firetube

d. Vertical firetube

D

One or more steel plates rolled into a cylinder welded together with the ends closed by rounded heads, is called a:

Select one:

a. Combustion chamber

b. Packaged boiler

c. Steam or water drum

d. Steam header

C

In a cast iron modular heating boiler, the operation of the burner of each module is controlled by a _____ that starts or stops modules in sequence as load demand increases or decreases.

Select one:

a. Thermostat

b. Flow controller

c. Step controller

d. Temperature sensor

C

A cyclone separator in a boiler steam drum:

Select one:

a. Discharges water into the scrubbers

b. Is located at the superheater outlet

c. Causes impurities to be thrown from the boiler water

d. Removes moisture from steam, using centrifugal force

D

When hot combustion gases travel through boiler tubes, which are surrounded by the boiler water, the boiler is called a:

Select one:

a. Coil type boiler

b. Firetube boiler

c. Tubular boiler

d. Watertube boiler

B

Electric boilers:

Select one:

a. Are economical to operate

b. Do not need gauge glasses

c. Do not need a chimney

d. Are low pressure boilers only

C

What is the saturation temperature of water at 100 kPa?

Select one:

a. 100C

b. 120C

c. 125C

d. 117C

B

A _____ is a water filled section, which surrounds the firebox in a locomotive boiler.

Select one:

a. Water leg

b. Steam dome

c. Boiler drum

d. Crown sheet

A

Internal furnaces are:

Select one:

a. Surrounded by water

b. Used to increase the strength of the drum

c. Contained within the windbox of a boiler

d. Mostly used to superheat the steam

A

Bottom Blow off on heating boilers may be required:

Select one:

a. only 2-3 times per year

b. Monthly with Class 1 Water Treatment

c. Weekly with Class 1 Water Treatment

d. Daily with Class 1 Water Treatment

D

Bent tube watertube boilers:

Select one:

a. Cannot be fitted with heat recovery components

b. Are externally fired

c. furnaces are lined with watertubes to absorb more radiant heat from the fire

d. Cannot have the furnace water-lined

C

An immersion electric boiler can have capacity as high as ___________ kW.

Select one:

a. 16 000

b. 30 000

c. 1500

d. 2100

C

A tube expander is used to:

Select one:

a. Bead the tube

b. Expand and flare the tube

c. Break loose scale outside the tube

d. Break loose scale inside the tube

B

The extended surfaces on the flat surface of the sections of a cast iron sectional boiler are used for the purpose of increasing the:

Select one:

a. Water space

b. Water circulation

c. Heating surface area

d. Steam space

C

The electrode type boiler:

Select one:

a. Requires water that conducts electricity

b. Utilizes bundles of electric elements

c. Must operate at very constant pressure

d. Requires a steady load

A

Firetube boilers have their tubes fixed into flat steel plates, known as:

Select one:

a. Shells

b. Drums

c. Headers

d. Tube sheets

D

Which of the following is NOT an advantage of an electric boiler over other boilers?

Select one:

a. Quiet operation

b. Very compact

c. More efficient

d. Does not need water treatment

D

In a boiler, the continuous blowdown pipe is located:

Select one:

a. A few inches below the water level in the steam drum

b. A few inches below the top of the mud drum

c. At the very bottom of the steam drum

d. Where the purest boiler water collects

A

An advantage of an electric boiler is that it:

Select one:

a. Produces superheated steam

b. Has a high efficiency of energy transfer from the electricity to the boiler water

c. Is fail-safe

d. Can be operated at high pressures and temperatures

B

A force that holds the manway doors of the boiler drums in place during operation is the:

Select one:

a. strength of the welds

b. boiler pressure

c. force on the yoke

d. bolting force

B

A disadvantage of an electric boiler is that it:

Select one:

a. Is very expensive to operate

b. Is inefficient

c. Requires alternating current

d. Has no chimney

A

Immersion boiler tube bundles:

Select one:

a. Have negligible electrical resistance

b. Withstand extremely high temperatures and pressures

c. Can be easily removed from the unit for maintenance purposes

d. Conduct current through the boiler water

C

The distribution pipe that injects feedwater inside a boiler:

Select one:

a. Improves the separation of steam and water

b. Introduces the feedwater against the radiant heating surfaces of the boiler

c. Is arranged to reduce thermal shock in the drum

d. Must be made of at least schedule 80 pipe

C

On older boilers, the masonry work that surrounded the furnace was termed:

Select one:

a. The boiler casing

b. The boiler setting

c. Masonry

d. The boiler firebox

B

In a vertical sectional boiler, the sections are placed:

Select one:

a. Above the draft hood

b. Side by side

c. On the furnace

d. One above the other

B

A watertube boiler is a boiler in which:

Select one:

a. Combustion gases pass through the tubes

b. Water passes around the tubes

c. Air passes through the tubes

d. Water passes through the tubes

D

The passage of combustion gases along the length of the boiler is referred to as a:

Select one:

a. Chimney pass

b. Combustion air pass

c. Combustion gas pass

d. Stack pass

C

The boiler MAWP is determined:

Select one:

a. According to the customers needs

b. After the hydrostatic test

c. at the welding stage

d. at the design stage

D

Which of these is not a steam drum internal component?

Select one:

a. Baffle

b. Intermittent blow off line

c. Chemical feed pipe

d. Chevron dryer

B

Water treatment chemicals are injected:

Select one:

a. Using an internal feed pipe located near the feedwater line.

b. Into the risers.

c. Into the steam space.

d. Into the mud drum.

A

Boiler handholes are openings that are use to:

Select one:

a. Inspect the boiler shell or drum

b. Inspect the windbox

c. Inspect the boiler uptake

d. Enter and inspect the boiler furnace

A

As per ASME section I and section IV, a steam boiler operating at a pressure of ______ or higher is considered a Power Boiler.

Select one:

a. 15 psig / 103.1 kPa

b. 14.7 psig / 100 kPa

c. 14.7 psig / 101.3 kPa

d. 15 psig / 100 kPa

D

In a boiler, all steam generating parts that are exposed to fire or hot gases must be:

Select one:

a. Covered with ceramic tile

b. Fitted with expansion joints

c. Covered by water

d. Made of fire brick

C

Operational system checks (rounds) are required for the care and operation of heating boilers, with the results recorded on log-sheets, as per the samples found in :

Select one:

a. ASME section IV

b. ASME section I

c. ASME section VII

d. ASME section VI

D

A pressure vessel that intercepts, cools, and depressurizes boiler blow-off water, in order to protect municipal sewer systems is called:

A) blowoff valve

B) pressure relief tank

C) deaerator

D) blowoff vessel

E) hotwell

D