Ch 53 Watertube Boilers

Front 1

In a longitudinal straight tube boiler the downcomer fed

a) "cool" water to the steam drum

b) "hot" water to a riser

c) "cool" water to a rear header

d) "cool" water to a front header

e) "hot" water to the water tubes

Back 1

c) "cool" water to a rear header

Front 2

A packaged watertube boiler having two mud drums is the

a) "O" type

b) "D" type

c) three drum bent-tube type

d) "A" type

e) Sterling type

Back 2

d) "A" type

Front 3

High pressure watertubes

a) are always smaller than firetubes

b) are elliptical in cross-section

c) are always straight

d) can be of various bent configurations

e) require pumps for circulation

Back 3

d) can be of various bent configurations

Front 4

Bent tube watertube boilers

a) cannot have the furnace water-lined

b) make more efficient use of the furnace

c) are externally fired

d) cannot be fitted with heat recovery components

e) have poor utilization of floor space

Back 4

b) make more efficient use of the furnace

Front 5

A cross drum straight tube boiler

a) could not have higher capacity than a longitudinal drum unit

b) was usually only of single pass design

c) could have more inclined tubes than a longitudinal drum unit

d) is a very popular design in today's plants

e) was internally fired

Back 5

c) could have more inclined tubes than a longitudinal drum unit

Front 6

Watertube boilers are better suited to higher pressures than firetube boilers, because they: 1. incorporate a bent tube design

2. are larger than firetube boilers

3. do not have flat surfaces subjected to pressure

4. usually have smaller diameter tubes

5. have smaller diameter drums

a) 1, 2

b) 1, 3, 5

c) 2, 3, 5

d) 1, 2, 5

e) 1, 3, 4, 5

Back 6

e) 1, 3, 4, 5

Front 7

The use of bent tube boiler designs allows the furnace wall to be lined with tubes, thereby exposing more of the heating surface to

a) convection heat

b) conducted heat

c) radiant heat

d) residual heat

e) latent heat

Back 7

c) radiant heat

Front 8

The bent tube boiler design allows the tubes to be attached radially on the outside of the

a) furnace

b) superheater

c) economizer

d) shell or drum

e) air preheater

Back 8

d) shell or drum

Front 9

Since furnace pressure is often positive on a packaged watertube boiler, in order to prevent flue gas leakage

a) an induced draft fan is incorporated

b) smoke stacks are made taller

c) an economizer is used

d) a steel casing forms a seal for the furnace

e) sootblowers cannot be used

Back 9

d) a steel casing forms a seal for the furnace

Front 10

Excessive vibrations caused by inadequate support of a watertube boiler can result in

a) insulation failure

b) water level control problems

c) tube failure

d) drum fracture

e) combustion control problems

Back 10

a) insulation failure

Front 11

A problem with a D-type watertube packaged boiler is

a) excessive vibration

b) ceiling height requirements

c) refractory maintenance for the external furnace

d) its need to be top supported

e) its poor water circulation

Back 11

a) excessive vibration

Front 12

A unit which would most likely utilize a cyclone furnace would be the

a) Sterling watertube boiler

b) steam generator

c) packaged watertube boiler

d) "D" type boiler

e) three drum bent-tube boiler

Back 12

b) steam generator

Front 13

Large steam generating units may have their superheaters located:

1. beneath the furnace

2. in the convection zone

3. in the main waterwall header

4. in the radiant zone

5. in the downcomer pipe

a) 2, 4

b) 4, 5

c) 1, 3

d) 1, 2, 5

e) 3, 4, 5

Back 13

a) 2, 4

Front 14

Large steam generators

a) are bottom supported

b) are fired by pulverized coal only

c) have sluggish water circulation

d) are usually of the water tube type

e) have beaded tubes

Back 14

d) are usually of the water tube type

Front 15

Large steam generating units are usually built so that highpressure, high temperature, and dry steam can be generated in order that

a) more fuel can be fired

b) large steam turbines can be used to drive electrical generators

c) higher furnace temperatures can be attained

d) less water treatment is necessary

e) stack temperatures can be maintained at a high level to prevent condensation

Back 15

b) large steam turbines can be used to drive electrical generators

Front 16

A steam generator economizer is usually located

a) between the air preheater and ID fan

b) between the primary and secondary superheaters

c) after the reheater

d) in the furnace section

e) between the air preheater and primary superheater

Back 16

e) between the air preheater and primary superheater

Front 17

The most economical fuel to burn in a steam generator is

a) natural gas

b) crushed coal

c) heavy fuel oil

d) pulverized coal

e) crude oil

Back 17

d) pulverized coal (reduced to fine material)

Front 18

Economizers

a) increase the boiler efficiency

b) are installed before the superheater

c) increase the steam temperature

d) increase the air temperature

e) increase the flue gas temperature

Back 18

a) increase the boiler efficiency

Front 19

Air heaters in a boiler

a) are installed between the superheater and the economizer.

b) reduce the temperature of the flue gases going to the stack.

c) help the boiler from freezing during the winter period.

d) increase the flue gas temperature.

e) maintain a steady higher temperature in the stack.

Back 19

b) reduce the temperature of the flue gases going to the stack.

Front 20

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

1. recover heat from the hot flue gases

2. improve boiler thermal efficiency

3. produce dryer steam

4. heat the feedwater

a) 1, 2

b) 2, 3

c) 1, 2, 4

d) 3, 4

e) 2, 3, 4

Back 20

a) 1, 2

Front 21

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

a) economizer

b) air heater

c) superheater

d) windbox

e) furnace

Back 21

b) air heater

Front 22

What's a boiler?

Back 22

A vessel containing water, heated by combustion gases

Front 23

HRT mean?

Back 23

Horizontal Return tube

Front 24

Most important thing to pay attention to while boiler is running?

Back 24

Water level

Front 25

7 major parts of a boiler

Back 25

Steam/mud drum, furnace, water column, fd fan, tubes, burner, steal outlet, gauge glass

Front 26

Why is an altitude gauge different from a standard gauge?

Back 26

Altitude gauge has a measurement of height or altitude, such as inches of water or inches of mercury

Front 27

Difference between safety valve on steam boiler and safety valve on hot water heater boiler?

Back 27

The handle

Front 28

What pressure does low pressure boiler become high pressure?

Back 28

103 KPa,or 15 psi

Front 29

What temperature and pressure does a lower pressure hot water boiler become high temperature and high pressure?

Back 29

121degC, or 1100kPa

Front 30

What are the three shapes of boiler?

Back 30

A,D,O