2Nd Class Fireman, High Pressure Boilers, Chapter 6, Notecards

Front 1

Acid

Back 1

Any water with a pH less than 7

Front 2

Alkaline

Back 2

Any water with pH greater than 7

Front 3

Automatic Blowdown

Back 3

- The process of automatically controlling the amount of boiler blowdown in order to maintain the level of total dissolved solids at the given setpoint.

- conductivity meters can be installed in the continuous blowdown piping to continuously monitor the conductivity of the boiler water.

- reduces carryover and scale buildup.

Front 4

Bottom Blowdown

Back 4

The process of removing water from the bottom of a boiler in order to remove impurities from the water

Front 5

Carryover

Back 5

- Small water particles and impurities being carried out of the boiler into the steam lines.

- result of high alkalinity, dissolved solids, and sludge in boiler water.

- can occur when a high water level causes water particles to be carried into steam lines.

Front 6

Caustic Embrittlement

Back 6

- A type of corrosion in which boiler metal becomes brittle because alkaline materials accumulate in cracks and crevices.

- can cause metal to crack along the seams and at the ends of tubes in the boiler.

- alkalinity caused by carbonates, bicarbonates, and hydroxides.

- caused by high alkalinity.

Front 7

Chemical Precipitation

Back 7

A process in which a chemical is added to raw makeup water to react with dissolved minerals, creating heavier particles that settle out of the solution

Front 8

Coagulation

Back 8

- A process in which the chemicals added to raw water cause suspended solids to adhere to each other, making them larger and heavier and causing them to settle out of the solution

- Reduces the concentration of suspended solids, silt, and reduces turbidity of the raw makeup water.

- chemicals used to do this include: aluminum sulfate, sodium aluminate, polymers, and ferrous sulfate.

Front 9

Condensate Polisher

Back 9

An ion-exchange conditioner that removes impurities from condensate

Front 10

Conductivity

Back 10

- The ability of material to allow the flow of electricity.

- the more dissolved solids there are the higher this will be.

Front 11

Conductivity Meter

Back 11

- An instrument that measures the electrical conductivity of a water sample to determine total dissolved solids present.

- located before the boiler.

Front 12

Continuous Blowdown

Back 12

- The process of continuously draining a small, controlled amount of water from a boiler to control the quantity of impurities in the remaining water.

- made at a point just below the low water level in the steam drum.

- discharge goes to the blowdown tank or to a flash tank.

- maintains more consistency in the level of chemicals within the boiler water.

- an advantage of this system is that solids are being removed as they are formed in the boiler water.

Front 13

Corrosion

Back 13

- The deterioration of the boiler metal caused by a chemical reaction with oxygen and carbon dioxide in the water

- causes pitting and channeling of the metal.

- can cause a boiler explosion

- oxygen and carbon dioxide should be removed from the water to prevent this.

Front 14

Deaerator

Back 14

A feedwater heater Operating under pressure used to separate oxygen and other gases from the steam before releasing the gases to the atmosphere through a vent

Front 15

Dealkalizer

Back 15

An ion-exchange water conditioner that removes alkalinity from water

Front 16

Demineralizer

Back 16

- An ion-exchange conditioner consisting of a strong cation-exchange resin and a strong anion-exchange resin that purifies water more than is possible with a zeolite softener.

- Used when lime-soda softeners are ineffective.

- Necessary for boilers operating above 1000 psi.

- The two basic types include: mixed-bed and two-vessel.

Front 17

External Boiler Water Treatment

Back 17

- The treatment of boiler water before it enters the boiler.

- typically used to remove scale-forming salts, oxygen, and noncondensable gases.

- Allows for easier treatment of boiler water internally.

- Includes clarification and filtration to remove suspended solids, various forms of water conditioning to remove hardness, and deaeration to remove oxygen and other dissolved gases.

- Coagulation, Filtration, Reverse Osmosis, Ion-Exchange Softeners, Lime-Soda Softeners, Dealkalizers, and Demineralizers.

Front 18

Filtration

Back 18

- The process in which makeup water passes through a filter to remove sediment, particulates, and suspended solids.

- Also prevents fouling or contamination during water softening.

Front 19

Foaming

Back 19

- The rapid fluctuation of the water level that occurs when steam bubbles are trapped below a film of impurities on the surface of the boiler water.

- steam bubbles have difficulty breaking through.

- water level becomes erratic, sight glass appears full one moment and empty the next.

- maintaining proper alkalinity of boiler water prevents this.

Front 20

Hardness

Back 20

- A measurement of scale-forming minerals dissolved in water.

- Usually checked with an electronic hardness tester.

Front 21

Hard Water

Back 21

Water that contains large quantities of dissolved scale-forming minerals, usually calcium and magnesium

Front 22

Internal Boiler Water Treatment

Back 22

- The Treatment of boiler water through the direct addition of chemicals into the boiler to prepare the boiler water for optimum operation.

- Used to control pitting, scale, and caustic embrittlement.

- Also used to condition impurities (hardness) for sedimentation, condition sludge for removal, scavenge remaining oxygen, and prevent foaming.

- The boiler water must be treated to prevent scale formation on tubes and heating surfaces, corrosion of the shell and tubes, caustic embrittlement at seams, and carryover of boiler water into superheater and steam lines.

- Chemical treatment with Caustic Soda (sodium hydroxide) and Phosphate, Amines, and Sodium Sulfite.

Front 23

Ion-Exchange Softener

Back 23

- A device that uses an ion-exchange resin, typically a zeolite, to exchange a sodium ion for an ion that causes hardness.

- uses sodium ions to soften the hard water

Front 24

Lime-Soda Softener

Back 24

- A water softener that uses lime and soda ash to remove hardness from water.

- primarily used to reduce dissolved calcium, magnesium, and silica.

- Uses chemical precipitation to remove dissolved compounds from water.

Front 25

pH

Back 25

- A measurement representing whether a substance is acidic, neutral, or alkaline

- boiler water pH requirements vary, but the pH value of boiler water should typically be between 8.5 and 11.5 to prevent scale formation

Front 26

Priming

Back 26

- Large slugs of water and impurities carried out of the boiler into the steam lines.

- very dangerous, can lead to water hammer.

- result of high alkalinity, dissolved solids, and sludge.

- can occur when a high water level causes water particles to be carried into steam lines.

Front 27

Reagent

Back 27

A chemical used in a chemical test to indicate the presence of a specific substance

Front 28

Reverse Osmosis (RO)

Back 28

- A filtration process in which the water to be treated is pressurized and applied against the surface of a semipermeable membrane in order to demineralize it and remove its impurities

- removes more material than standard filtration

- room temperature water is needed

Front 29

Scale

Back 29

- An accumulation of compounds like calcium carbonate and magnesium carbonate on the water side of the heating surfaces of a boiler

- formation on tubes and drums is one of the causes of boiler failure

- causes the boiler metal to overheat because it acts as an insulator

- overheating of the metal causes leaks, cracks, bags, blistering, distortion of tubes and tube sheets, and boiler explosion

- reduces boiler efficiency.

Front 30

Surface Blowdown

Back 30

- The process of removing water from the boiler near the NOWL to control the quantity of impurities in the remaining water or to remove a film of impurities on the surface of the water.

- the maximum size of the line is 2.5”

Front 31

Titration Test

Back 31

A Water Treatment test in which a reagent is added to a sample to determine the concentration of a specific dissolved substance

Front 32

Total Dissolved Solids

Back 32

- A measurement of the concentration of dissolved impurities in boiler water.

- can be measured with a conductivity meter.

Front 33

Vent Condenser

Back 33

An internal element in some types of deaerators that condenses steam and uses the heat produced to warm the feedwater

Front 34

Water Softener

Back 34

A boiler water pretreatment device used to reduce hardness

Front 35

Zeolite

Back 35

One of a group of minerals including silicates of aluminum, sodium, and calcium that are used in ion-exchange softeners

Front 36

Blowdown Tank

Back 36

A vented tank that cools blowdown water and steam to protect sewer lines from the high temperatures and pressures of blowdown water.

Front 37

Filter

Back 37

A device that contains a porous substance through which fluid can pass but particulate matter cannot.

Front 38

Blowdown Separator

Back 38

A small tank in which makeup water is added to the boiler blowdown water after it flashes in order to reduce the discharge water temperature.

Front 39

Anion

Back 39

A negatively charged ion.

Front 40

Blowdown Heat Recovery System

Back 40

Equipment that is installed to reclaim heat that is normally lost during continuous blowdown.

Front 41

Cation

Back 41

A positively charged ion.

Front 42

Flash Tank

Back 42

- A tank used with a continuous blowdown system to recover the flash steam from the water being removed during blowdown.

- recovering this steam from continuous blowdown can often significantly reduce operating costs.

- can be under vacuum.

Front 43

Flash Steam

Back 43

The steam created when water at a high temperature experiences a sudden drop in pressure.

Front 44

Accessory

Back 44

A piece of equipment that is not directly attached to a boiler but is necessary for its safe and efficient operation.

Front 45

Carbonic Acid

Back 45

- This is an acid that forms when carbon dioxide dissolves in boiler water.

- causes corrosion in the condensate return lines.

Front 46

Cold Lime-Soda Softener

Back 46

- Used at ambient temperature.

- Softens water and removes sludge.

- Uses chemical precipitation to remove impurities.

Front 47

Hot Lime-Soda Softener

Back 47

- Used at temperatures above 212 degrees Fahrenheit.

- Uses exhaust or live steam to maintain the high temperatures required.

- Quicker than the cold lime-soda softener but performs the same function.

- Softens water and removes sludge.

- Uses chemical precipitation to remove impurities.

Front 48

Cation-Exchange Resin

Back 48

- Exchanges hydrogen ions for metal ions.

Front 49

Anion-Exchange Resin

Back 49

- Exchanges hydrogen ions for ions such as chloride and silicate.

Front 50

Caustic Soda (sodium hydroxide) and Phosphate

Back 50

- adding this to the boiler water can prevent scale formation by changing calcium carbonate and magnesium carbonate into non-adhering sludge.

Front 51

Amines

Back 51

- generally added to the boiler water to protect the condensate lines from carbonic acid.

Front 52

Sodium Sulfite

Back 52

- often added to feedwater to remove the remaining oxygen to prevent pitting of the boiler metal.

- forms sodium sulfate after reacting with the oxygen in the water.

Front 53

Scale Picture

Back 53

Back (Definition)

Front 54

Corrosion Picture

Back 54

Back (Definition)

Front 55

Priming and Carryover

Back 55

Back (Definition)

Front 56

Priming and Carryover Picture

Back 56

Back (Definition)

Front 57

Foaming Picture

Back 57

Back (Definition)

Front 58

Carbonic Acid Damage Picture

Back 58

Back (Definition)

Front 59

Water Filters Picture

Back 59

Back (Definition)

Front 60

Reverse Osmosis Picture

Back 60

Back (Definition)

Front 61

Ion-Exchange Water Softeners Picture

Back 61

Back (Definition)

Front 62

Cold Lime-Soda Process Picture

Back 62

Back (Definition)

Front 63

Hot Lime-Soda Process Picture

Back 63

Back (Definition)

Front 64

Demineralizers Picture

Back 64

Back (Definition)

Front 65

Deaerators Picture

Back 65

Back (Definition)

Front 66

Vent Condensers Picture

Back 66

Back (Definition)

Front 67

Blowdown Tanks Picture

Back 67

Back (Definition)