2Nd Class Fireman, High Pressure Boilers, Chapter 1, Exam Q&a

Front 1

A low pressure steam boiler has an MAWP of ____ psi

Back 1

15

Front 2

The higher the steam pressure, the higher the _____ of the water in the boiler

Back 2

Boiling point

Front 3

____ is the amount of energy equal to the evaporation of 34.5 lb of water/hr from and at a feedwater temperature of 212 degrees Fahrenheit

Back 3

Boiler horsepower

Front 4

When a steam boiler is operating at 100 pounds per square inch gauge pressure (psig), the temperature of the water and steam will be approximately ____ degrees Fahrenheit

Back 4

338

Front 5

A horizontal return tubular (HRT) boiler is a _____ boiler

Back 5

Firetube

Front 6

As steam pressure in a boiler increases, there is a corresponding increase in the ____

Back 6

Temperature

Front 7

A sudden drop in pressure from 100 psig to 0 psig without a corresponding drop in temperature could result in a(n) ____

Back 7

Explosion

Front 8

Water will boil and turn to steam when it reaches ____ degrees Fahrenheit at atmospheric pressure at sea level

Back 8

212

Front 9

_____ is the ratio of the heat absorbed by the boiler (output) to the heat available in the fuel (input)

Back 9

Thermal efficiency

Front 10

Baffles are used to direct gases so that they come in close contact with the ____

Back 10

Boiler heating surface

Front 11

_____ stress is stress that occurs when two forces of equal intensity act parallel to each other but in opposite directions

Back 11

Shear

Front 12

Some watertube boilers are equipped with ____ to increase the heating surface and the life of the furnace refractory

Back 12

Waterwalls

Front 13

A disadvantage of a vertical firetube boiler is that it requires ____

Back 13

A high ceiling

Front 14

In a firetube boiler, the heat produced by gases of combustion _____

Back 14

Passes through the tubes

Front 15

Watertube boilers were designed to operate at pressure as high as _____ psi, a point known as the critical pressure of steam

Back 15

3206

Front 16

A mud drum, if used, is the lowest part of the water side of a(n) _____ boiler

Back 16

Watertube

Front 17

A _____ boiler is a watertube boiler in which replaceable serpentine tubes are connected to the upper and lower drums and surround the firebox

Back 17

Flex-tube

Front 18

In electrode electric boilers, heat is generated by electric current flowing from one electrode to another electrode through the _____

Back 18

Boiler water

Front 19

A high pressure steam boiler operates at a steam pressure over _____ psi

Back 19

15

Front 20

A condensing economizer recovers _____ BTU/lb from the heat in the water vapor

Back 20

970

Front 21

Boiler tubes are manufactured using materials that meet ____ specifications

Back 21

ASME

Front 22

In a watertube boiler, the heated water inside the tubes becomes _____, causing it to rise

Back 22

Less dense

Front 23

Cogeneration produces _____ for use in a process or heating

Back 23

Electricity

Front 24

A _____ is a device that converts mechanical energy into electrical energy by means of electromagnetic induction

Back 24

Generator

Front 25

_____ is used to support and protect electrical conductors

Back 25

Conduit

Front 26

Boiler efficiency varies considerably from one design to another, with standard boilers about ____ % efficient

Back 26

80

Standard boilers are about 80% efficient and near-condensing boilers are about 86% efficient

Front 27

A ____ (MCC) combines individual control units into standard modular structures joined on formed sills.

Back 27

Motor control center

Front 28

Why are firetube boilers restricted compared to watertube boilers?

Back 28

Firetube boilers do not go higher than 350 psi. There is also not as much heat. Watertube boilers can go as high as 3206 psi.

Front 29

Which has the greater heating surface, watertube or firetube?

Back 29

A watertube has a larger heating surface because you have more area for the gases of combustion

Front 30

What are the 3 forms of heat transfer?

Back 30

Convection (warm air rising), radiant (visible, sun heating the ground), conduction (ground heats the air)

Front 31

What are the three types of stresses?

Back 31

Tensile, shear, compression

Front 32

What are some basic things used to increase energy efficiency? _____

Back 32

Baffles, waterwalls, and economizers

Front 33

A(n) ____ is a closed vessel used for heating water to generate steam by direct application of heat from combustible fuels or electricity.

Back 33

Boiler

Front 34

A(n) _____ boiler is a boiler in which steam or other vapor is generated at pressures exceeding 15 psi.

Back 34

power steam

Front 35

A high pressure steam boiler is a boiler that operates at a maximum allowable working pressure (MAWP) of more than ____ psi

Back 35

15

Front 36

When a steam boiler is operating at 100 pounds per square inch gauge pressure (psig), the temperature of the water and steam will be approximately _____ degrees Fahrenheit.

Back 36

338

Front 37

____ is the soft muddy residue produced from impurities in water that accumulates in low spots in a boiler.

Back 37

sludge

Front 38

_____ is the pressure at which the density of water and steam are the same.

Back 38

critical pressure

Front 39

_____ allow for circulation between the lower drum and the box headers.

Back 39

Downcomers

Front 40

In resistance-coil electric boilers, electricity flows through a ____ conductor, which generates heat through resistance.

Back 40

coiled

Front 41

A(n) _____ boiler is a boiler that uses the municipal solid waste that would normally go to landfills

Back 41

refuse

Front 42

Waste boilers can use the heat from the incineration of _____

Back 42

industrial by-products

Front 43

A(n) ____ does not requires a burner to burn a fuel because the hot gases already exist as waste from another process.

Back 43

heat recovery steam generator

Front 44

The ____ ensures that boilers and fittings are strong enough and made of suitable materials that can withstand the continuous stress of boiler operation.

Back 44

ASME code

Front 45

Fire tubes in a firetube boiler are subjected to ____ stress

Back 45

compressive

Front 46

Through stays are used to prevent _____ in boilers.

Back 46

bulging

Front 47

Standard boilers are about ____ % efficient

Back 47

80

Front 48

A ____ is a set of tubes that is placed in the furnace area of watertube boilers and used to increase the heating surface of boilers and the service life of refractory.

Back 48

waterwall

Front 49

Finned boiler tubes can be used to increase the ____ of the boiler.

Back 49

heat transfer surface

Front 50

_____ are used to direct the gases of combustion so that they come in close contact with the boiler heating surface.

Back 50

baffles

Front 51

For both firetube and watertube boilers, the tubes are measured by their _____

Back 51

outside diameters

Front 52

Oil refineries typically use steam for ____ in the refining process.

Back 52

distillation of petroleum products

Front 53

Steam can be used to help _____ concrete

Back 53

dry

Front 54

Turbines require _____ for steam expansion without condensation

Back 54

superheated steam

Front 55

____ generators are the most common generators used to produce electrical power.

Back 55

AC (alternating current)

Front 56

By using ______, it is possible for one plant to supply most or all of the required electricity, process steam, heater water, and air conditioning needed for a facility.

Back 56

cogeneration

Front 57

A(n) _____ does not require a burner because it uses hot waste heat gases from another process.

Back 57

Heat recovery steam generator

Front 58

What is the greatest loss in a power plant?

Back 58

Heat out of the stack.

Front 59

What does ASME stand for?

Back 59

American Society of Mechanical Engineers