Water Treatment

Front 1

External Water Treatment types

Back 1

Evaporating - Heat to evaporate water to remove dissolved solids

Reverse Osmosis - High pressure to force water through membrane

Deaerating - Heat to drive off dissolved gases (ex. oxygen, carbon dioxide)

Front 2

Internal Water Treatment types

Back 2

Adding chemicals to treat water

- removes residual oxygen

- removes hardness

- adjusts pH

- adjusts TDS (Total Dissolved Solids)

- disperses sludge

- reduces foam

- removes scaling

- protects condensate system from corrosion

Front 3

Clarifiers purpose?

Back 3

Remove suspended solids from water by allowing them to settle by gravity.

(commonly used to treat river water)

Front 4

Coagulations purpose?

Back 4

Used in conjunction (occurs same time) with settling tanks/clarifiers

Removes fine particles by gathering them together to form larger particles.

Front 5

Coagulants 3 more common are?

Back 5

Aluminum sulfate, Al2(SO4)3

Sodium Aluminate, Na2Al2O4

Aluminum hydroxide, Al(OH)₃

Front 6

Filter aid tubular filters

The cages are covered with?

Back 6

Socks of dacron or polyethylene

Front 7

cartridge filter purpose

Back 7

Used in conjunction with settling tanks to remove fine particles

Front 8

Cold Lime Soda Softening

Back 8

Uses lime (calcium hydroxide) Ca (OH)2 and soda (sodium carbonate) Na2CO3, to precipitate hardness from solution.

Front 9

Ion Exchange

Back 9

Exchanging calcium Ca2+ and magnesium Mg2+ cations against Na+ or H+ cations

Front 10

Sodium Zeolite Water Softeners

Back 10

When Ca2+ and Mg2+ ions containing hard water is passes through a bed of sodium zeolite, the sodium ions are replace by the calcium and magnesium ions.

Na2Z + Ca(HCO3)2 → 2NaHCO3 + CaZ

Na2Z + MgSO4 → 2Na2SO4 + MgZ

Front 11

Cation Exchange

Back 11

Hardness causing magnesium and sodium cations removed

TDS(Total dissolved solids) does not change

Front 12

Hydrogen zeolite softeners ***

Back 12

-Replace all cations with hydrogen

-Regenerate using acid (sulfuric acid)

-Dissolved solids in water are converted to acids

Front 13

Resins purpose? (2) ***

Back 13

One resin replaces cations with hydrogen (Cation resin)

One resin replaces anions with hydroxide (Anion resin)

Front 14

Cation resin is regenerated with _? ***

Back 14

Sulfuric acid (H2S04)

Front 15

Anion resin is regenerated with _? ***

Back 15

Caustic soda (NaOH)

Front 16

Mechanical deaeration purpose and the important gases?

Back 16

-Removes dissolved gases from water

-Important gases are oxygen and carbon dioxide

Front 17

Mechanical deaeration steps (3)

Back 17

-Divide water up into small droplets (Heats up quickly)

-Heat water droplets to drive off dissolved gases

-Scrub gases away from water

Front 18

Pressure is controlled by? *** (Deaerator)

Back 18

Regulating steam flow to deaerator

Front 19

Level controlled by? (3) (Deaerator)

Back 19

Regulating water flow to deaerator

Overflow valve

High and low level alarm

Front 20

temperature controlled by? (Deaerator)

Back 20

Controlled by steam pressure

Front 21

Deaeration controlled by? (Deaerator)

Back 21

By a manual vent at top of unit

Front 22

Deaerator purpose (3)

Back 22

Remove dissolved gases

Provide storage area for treated feedwater

To heat feed water and reduce thermal shock

Front 23

Cations and anions examples?

Back 23

cations- H,Mg,Na,Fe,Cu etc.

Anions- Cl,OH,SO4,PO4,CO3 etc.

Front 24

Purpose of deaerator (3)

Back 24

- remove dissolved gases

- storage for treated feed water

- heat feed water and reduce thermal shock

Front 25

Internal water treatment

Back 25

Treat water (add chemicals) and to prevent corrosion, scale and sludge formation, foaming and possible failure

Front 26

Mechanical deaeration steps (3)

Back 26

1. Divide water into smaller droplets

2. Heat water droplets to drive off dissolved gases

3. Scrub gases away from water so they cannot redissolve

Front 27

Point of addition depends on? (2)

Back 27

Results and reactions between chemicals

Front 28

***How is foaming controlled?

Back 28

Blowoff and adding defoamer

Front 29

Caustic embrittlement results from? And hows it treated? (2) ***

Back 29

Results from High concentrations of caustic soda

Treated by:

Not adding caustic into water

Adding sodium nitrate***,tannings, lignins

Front 30

Hydrogen Zeolite Softners examples

Back 30

NaCl (Sodium Chloride) + H2Z (Hydrogen Zeolite) -> Na2Z (Sodium Zeolite) + HCl (Hydrochloric Acid)

CaCO3 (Calcium Carbonate) + H2Z (Hydrogen Zeolite) -> CaZ (Calcium Zeolite) + H2CO4 (Carbonic Acid)

Front 31

Chemicals may be added where? (4)

Back 31

Boiler steam drum, condensate system, steam lines, deaerator (storage section)

Front 32

Scaling is a result of?

Back 32

Hardness

Front 33

pH must be maintained at? ***

Back 33

10.5 to minimize acid corrosion

Front 34

pH level may be increased in the steam drum and feed water system by adding what? ***

Back 34

Caustic soda and sodium phosphate

Front 35

Oxygen scavenging reactions

Back 35

2Na2SO3 (Sodium sulfite)+O2 (dissolved oxy)->2Na2SO4 (sodium sulfate)

N2H4 (hydrazine)+02(dissolved oxy)->N2 (nitrogen)+2H2O (water)

Front 36

sludge is removed by what and why is it bad?

Back 36

It sticks onto metal and is removed in the blowoff.

Chemicals (organic) used are:

-starch from corn/potatoes

-Lignin and tannin from wood

-Alginates from seaweed

Front 37

Oxygen scavengings purpose and what chemicals are used?

Back 37

To remove oxygen to avoid corrosion

Chemicals used:

-hydrazine (carcinogenic (causes cancer))

- sulfite (increases dissolved solids)

Front 38

Demineralizers remove all _?

Back 38

Inorganic dissolved solids to produce clean water. Ex Cation resin regenerates w/ sulfuric acid (H2SO4), Anion resin regenerates w/ Caustic soda (NaOH)

Front 39

Foaming may be caused by? (4)

Back 39

High dissolved/suspended solids, organic matter or oils

Front 40

Water treatment to prevent? (4)

Back 40

Prevent:

-Sludge formation (On boiler surfaces), Scale (On heating surfaces), Corrosion (Boiler metal), carryover of impurities (in boiler water)

Front 41

Impurity problems in boiler water (3)

Back 41

Suspended solids, dissolved solids, and dissolved gases

Front 42

Suspended solids are? & How to remove them?

Back 42

Solid material that don't dissolve in the water ex. mud clay, sand etc. Removed from boiler blowdown.

Front 43

Dissolved solids are? & how are they tested?

Back 43

Solids that dissolve in water and the concentration dissolved is measured by testing the water conductivity.

Front 44

Dissolved gases concerns & why?

Back 44

Gases dissolve in water but the two concerns are oxygen (forms iron oxide rust & corrosion) and carbon dioxide (produce carbonic acid which lowers ph & corrosion results in grooving.)

Front 45

Hardness consists of what salts?

Back 45

Calcium and Magnesium. Ex. Calcium Bicarbonate Ca(HCO3)2, Magnesium Bicarbonate Mg(HCO3)2, Calcium sulfate CaSO4, Magnesium Sulfate MgSO4

Front 46

Temporary hardness are? & how to remove?

Back 46

Bicarbonates which are removed by heating water to 100 degrees Celsius. Calcium bicarbonate and magnesium bicarbonate form.

Front 47

Permanent hardness are from?

Back 47

Other calcium and magnesium salts Ex. Calcium and magnesium sulfate, calcium and magnesium chloride.

Front 48

Scaling results in?

Back 48

Dissolved solids that settle on heating surfaces causing tube metals to overheat.

Front 49

pH levels and what is recommended?

Back 49

pH less than 7.0 = acidic, pH at 7.0 = neutral, pH greater than 7.0 = alkaline or basic, pH is recommended to be above 10.5

Front 50

pH depends on?

Back 50

Temperature. (pH cooled is higher than pH of same water)

Front 51

Water treatment required depends on? (2)

Back 51

Water source and boiler pressure. (Higher pressure, more pure water must be)

Front 52

Sources of boiler water (2)

Back 52

Surface water, Ground water

Front 53

Demineralizer Reactions (Cation)

Back 53

Cation: 1. CaSO4 (Calcium Sulfate) + H2Z (Hydrogen Zeolite) -> CaZ (Calcium Zeolite) + H2SO4 (Sulfuric Acid)

2. Ca(HCO3)4 (Calcium Bicarbonate) + H2Z (Hydrogen Zeolite) -> CaZ (Calcium Zeolite) + H2CO3 (Carbonic Acid)

3. Carbonic Acid Breakdown

H2CO3 (carbonic acid) -> H20 + CO2 (carbon dioxide)

Anion: H2SO4 (Sulfuric Acid) + Z(OH)2 (Anion zeolite) -> ZSO4 (zeolite sulfate) + 2H20

Front 54

Demineralizer Reactions (Anion)

Back 54

Anion 1.H2SO4 (Sulfuric acid) + Z(OH)2 (anion zeolite) -> ZSO4 (zeolite sulfate) + 2h20 (water)

2. HCl (Hydrochloric Acid) + Z(OH)2 (Anion Zeolite) -> ZCl2 (Zeolite chloride) + 2H20 (water)

Front 55

Amines used for?

Back 55

Combat return line corrosion by neutralizing amines ( Raise pH of condensate) and filming amines ( Coat piping to protect it)

Front 56

Chemical Feed pumps use _ displacement pumps.

Back 56

Positive

Front 57

Gravity Drip feeder is used for what chemicals?

Back 57

Feeds powered and liquid chemicals into water line by gravity

Front 58

Water testing methods for hardness are?

Back 58

Soap test - add soap solution drop by drop

Titration test - Hardness buffer is added, hardness indicator turns red, add hardness reagent drop by drop til colour goes red to blue, # of drops = total hardness.

Front 59

Phenolphthalein determines alkalinity from? (2)

Back 59

Hydroxide and carbonates only

Front 60

Methyl Orange determines alkalinity from?

Back 60

All alkaline dissolved solids

Front 61

Dissolved solids causes solution to ___ better.

Back 61

Conduct electricity better (TDS can be determined)

Front 62

Sodium sulfite is tested to ensure no __ remains.

Back 62

Ensures no 02 (oxygen) remains