Elements of Boiler Systems

Question 1

In a Underfeed Stoker the channel through which the fuel is fed is called?

Answer 1

A Retort

Question 2

In a Underfeed Stoker the underfire air passes through openings in the grate called?

Answer 2

Tuyeres

Question 3

In a bubbling Fluidized bed boiler the region between the top of the bed and the top of the furnace is called?

Answer 3

The freeboard

Question 4

A device that normally uses air or steam to do its job is the:
Select one:

a.
Siphon

b.
Operating control

c.
Burner

d.
Soot blower

Answer 4

d.
Soot blower

Question 5

What is the name for refractory that is a low-density material and suitable for filling cracks in monolithic refractory?

a. Gunnable

b. Firebrick

c. Ash clinker

d. Castable

Answer 5

a. Gunnable

Question 6

Shot cleaning pellets are transported to the top of the boiler:
Select one:

a. Using an air stream

b. Manually

c. By a steam injection system

d. By a hydraulic hoisting system

Answer 6

a. Using an air stream

Question 7

A modulating pressure atomizer has its return oil flow regulated by:
Select one:

a. A modulating valve to the burner

b. A firing rate control valve in the return line

c. A solenoid valve in the return line

d. A pressure regulator

Answer 7

b. A firing rate control valve in the return line

Question 8

The purpose of the combustion controls on a boiler is to:
Select one:

a. Maintain the proper ratio of combustion air to flue gas

b. Maintain a constant fuel flow

c. Vary the air and fuel ratio with variations in firing rate

d. Maintain the proper ratio of air to fuel

Answer 8

d. Maintain the proper ratio of air to fuel

Question 9

A long retractable soot blower:
Select one:

a. Has nozzles throughout its full length

b. Is used to clean furnace walls

c. Rotates and blows while extending and retracting

d. Blows only when fully extended

Answer 9

c. Rotates and blows while extending and retracting

Question 10

Which is NOT a fireside surface cleaning method?

a. Slagging

b. Acoustic cleaning

c. Soot blowers

d. Rapping

Answer 10

a. Slagging

Question 11

What controls the combustion airflow to the furnace of an older HRT boiler and the flue gas flow from the furnace?

a. Outlet damper control

b. Overfire air or damper control

c. Inlet damper control

d. Underfire air and motor speed control

Answer 11

b. Overfire air or damper control

Question 12

During a soot blowing operation the boiler firing rate should be at least:
Select one:

a. 15%

b. 50%

c. 20%

d. 80%

Answer 12

b. 50%

Question 13

What does a short, single-nozzle retractable wall blower remove?

a. Deposits from the convection surfaces

b. Deposits from the radiant heating surfaces

c. Water-wall ash deposits

d. Deposits located in the superheater and reheater banks

Answer 13

c. Water-wall ash deposits

Question 14

The amount of pre-mix air to an atmospheric burner is typically:
Select one:

a. 10% to 12%

b. 5% to 8%

c. 20% to 50%

d. 30% to 40%

Answer 14

d. 30% to 40%

Question 15

Inlet damper control on a fan:
Select one:

a. Requires more power to drive the fan when the vanes are closed.

b. Requires less power to drive the fan at reduced loads.

c. Is only used on forced draft fans.

d. Is far less complicated than outlet damper control.

Answer 15

b. Requires less power to drive the fan at reduced loads.

Question 16

The low water fuel cut-off of heating boiler must shut the fuel off if the water level drops:
Select one:

a. Below the top row of tubes

b. Quickly

c. To an unsafe level

d. The lowest permissible water level

Answer 16

c. To an unsafe level

Question 17

A solenoid type fuel valve;
Select one:

a. Is held closed by fuel gas pressure

b. Always opens rapidly

c. Is held closed by electrical current

d. Closes slowly

Answer 17

a. Is held closed by fuel gas pressure

Question 18

In a typical bubbling fluidized bed boiler, to what depth is the combustion bed maintained?
Select one:

a. 1.5 metres

b. 1 metre

c. 2 metres

d. 2.5 metres

Answer 18

b. 1 metre

Question 19

The pressure range for pressure-atomizing burners fired with light fuel oil is approximately:
Select one:

a. 50 to 100 kPa

b. 150 to 250 kPa

c. 300 to 550 kPa

d. 550 to 700 kPa

Answer 19

d. 550 to 700 kPa

Question 20

Fluidized bed boilers can successfully burn coal with ash contents as high as
Select one:

a. 30%

b. 55%

c. 60%

d. 70%

Answer 20

d. 70%

Question 21

If there is insufficient combustion air to a boiler furnace, the result will be:
Select one:

a. High CO2 readings in the flue gas

b. High CO in the flue gases

c. A reduction in draft fan power requirements

d. Higher than normal flue gas temperature

Answer 21

b. High CO in the flue gases

Question 22

What do natural draft systems that rely on the hot gases in the chimney have?

a. Less specific gravity than an unequal height column of colder atmospheric air

b. More density than an equal height column of colder atmospheric air

c. More mass than an equal height column of colder atmospheric air

d. Less mass than an equal height column of colder atmospheric air

Answer 22

d. Less mass than an equal height column of colder atmospheric air

Question 23

In a mechanical atomizing burner with three fixed capacity burners, the Intermediate and high fire burner nozzles may have higher capacities than the primary burner nozzle:
Select one:

a. To give greater firing variations

b. To prevent pressure surges

c. Because of the pump being of the positive displacement type

d. To allow slower boiler warm-ups

Answer 23

d. To allow slower boiler warm-ups

Question 24

What does the operating mechanism of a slow-opening valve require?

a. Markings on the valve body indicating open and close positions

b. At least five 360° turns to change from fully closed to fully open

c. A sliding disc that can cut through impurities

d. Moving a lever through a small arc of about 90°

Answer 24

b. At least five 360° turns to change from fully closed to fully open

Question 25

The approximate amount of excess air for combustion of a gaseous fuel is:
Select one:

a. 6 - 8%

b. 3 - 5%

c. 10 - 15%

d. 3 - 10%

Answer 25

d. 3 - 10%

Question 26

The result of a condensate receiver that is too small could be:
Select one:

a. High boiler water level

b. Overflowing of the condensate receiver

c. Loss of make-up water

d. Low make-up water flow rates

Answer 26

b. Overflowing of the condensate receiver

Question 27

An atomizing air compressor is usually:
Select one:

a. A variable displacement type

b. A centrifugal type

c. An axial type

d. A small, rotary air compressor

Answer 27

d. A small, rotary air compressor