Boiler & Cooling Slides for learning and understading .ppt

its boiler water treatment

1. •PT Poly Arrad Pusaka has the commitments to the PT Poly Arrad Pusaka has the commitments to the
customers:customers:
1. Select the 1. Select the right chemicals-treatment programright chemicals-treatment program
2. Supply high quality products, with 2. Supply high quality products, with Products Products
Quality ControlQuality Control system system
3. Supply product 3. Supply product on-time deliveryon-time delivery
4. Give a good 4. Give a good technical servicestechnical services and supported by and supported by
experienced peopleexperienced people
5.5.Control products inventory in-siteControl products inventory in-site to prevent to prevent
chemicals stock outchemicals stock out
6. Concern on 6. Concern on Health, Safety, and EnvironmentHealth, Safety, and Environment
11
CommitmentsCommitments

2. 22
BOILER TREATMENT BOILER TREATMENT
PROGRAMPROGRAM
•Boiler Treatment Program to be applied Boiler Treatment Program to be applied
depends on:depends on:
--System Operation DesignSystem Operation Design
--Steam UsesSteam Uses
--Raw Water Quality.Raw Water Quality.

3. 33
PURPOSE OF BOILER WATER PURPOSE OF BOILER WATER
TREATMENTTREATMENT
•Failure PreventionFailure Prevention
–Deposit ControlDeposit Control
–Corrosion MinimizationCorrosion Minimization
–Maximizing Steam PurityMaximizing Steam Purity
•ReliabilityReliability
–Uninterrupted ProductionUninterrupted Production
•Helps prevent missed ordersHelps prevent missed orders
•Helps meet on demand delivery scheduleHelps meet on demand delivery schedule
•Assists “zero defect” strategyAssists “zero defect” strategy
–Routine MaintenanceRoutine Maintenance
•Reduces crises maintenanceReduces crises maintenance
•Allows planned preventive maintenanceAllows planned preventive maintenance

4. 44
PURPOSE OF BOILER WATER PURPOSE OF BOILER WATER
TREATMENTTREATMENT
•EfficiencyEfficiency
–Fuel SavingFuel Saving
–Lower Water CostsLower Water Costs
•Raw waterRaw water
•WastewaterWastewater
•Helps meet water use restrictionsHelps meet water use restrictions
•FinancialFinancial
–Less Frequent Acid CleaningLess Frequent Acid Cleaning
–Decreased Overall Maintenance CostsDecreased Overall Maintenance Costs
–Reduced Downtime CostsReduced Downtime Costs

5. 55
The Boiler Treatment Programs include:The Boiler Treatment Programs include:
- - Oxygen ScavengingOxygen Scavenging
- - Internal TreatmentInternal Treatment
- - Condensate TreatmentCondensate Treatment
BOILER TREATMENT BOILER TREATMENT
PROGRAMPROGRAM

6. 66
OXYGEN SCAVENGING OXYGEN SCAVENGING

7. 77
WATER
Fe(OH)
3
O
2
Fe
2+
OH
-
O
2
ANODE CATHODE
ANODE REACTION
Fe
.
= Fe
++
2e
-
CATHODE REACTION
1/2 O
2
+ H
2
O + 2e
-
= 20H
-
ELECTRON FLOW
CORROSION OF IRON BY CORROSION OF IRON BY
OXYGENOXYGEN
MECHANISM
•IRON IS OXIDIZED ON THE SURFACE (ANODE) - METAL LOSSIRON IS OXIDIZED ON THE SURFACE (ANODE) - METAL LOSS
•OXYGEN IS REDUCED (CATHODE)OXYGEN IS REDUCED (CATHODE)

8. 88
Oxygen PittingOxygen Pitting

9. 99
OXYGEN CONTROL OXYGEN CONTROL
PROGRAMPROGRAM
•MECHANICALMECHANICAL
–DEAERATORS to DEAERATORS to
remove dissolved remove dissolved
gases (O2, CO2)gases (O2, CO2)
•CHEMICALSCHEMICALS
–SULFITESULFITE
–HYDROQUINONEHYDROQUINONE
–HYDRAZINEHYDRAZINE

10. 1010
VARIABLES INFLUENCING VARIABLES INFLUENCING
SCAVENGER REACTIONSCAVENGER REACTION
•TIMETIME
•TEMPERATURETEMPERATURE
•pHpH
•CATALYSTCATALYST

11. 1111
VARIABLES AFFECTING OXYGEN VARIABLES AFFECTING OXYGEN
SCAVENGER PERFORMANCESCAVENGER PERFORMANCE
OXYGEN SCAVENGEROXYGEN SCAVENGER
•SULFITESSULFITES
•HYDRAZINEHYDRAZINE
•HYDROQUINONEHYDROQUINONE
•NN
22 BASED BASED
•ASCORBIC ACIDASCORBIC ACID
*FOR GOOD OXYGEN SCAVENGING*FOR GOOD OXYGEN SCAVENGING
MINIMUM TEMP*
80
0
F
190
0
F
REACTIVITY GREATER
THAN N
2H
4 AT TEMPS
LESS THAN 180
0
F
150
0
F
180
0
F
MINIMUM pH*
8.5 - 10
> 9.5
> 8.5
> 9.0
> 7.0

12. 1212
O2 SCAVENGER EFFICACYO2 SCAVENGER EFFICACY
pH 9.5
TIME 6min
TEMP 134C
DO 30ppb
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
100
90
80
70
60
50
40
30
20
10
0
SCAVENGER (ppm)
HYDRAZINE
HQ
DEHA/HQ
ASCORBIC ACID
CARBOHYDRAZIDE
MEKO
% OXYGEN
REMOVED

13. 1313
O2 SCAVENGER EFFICACYO2 SCAVENGER EFFICACY
TIME 6min
TEMP 134C
DO 30ppb
pH 9.5
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
SCAVENGER (ppm)
40
10
0
20
30
50
60
80
70
90
100
5ppb Cu
DEHA/HQ
HYDRAZINE
ASCORBIC ACID
CARBOHYDRAZIDE
HQ
MEKO
% OXYGEN
REMOVED

14. 1414
MONITORINGMONITORING
•1)1) PRIMARY SAMPLE POINT FOR OXYGEN TESTINGPRIMARY SAMPLE POINT FOR OXYGEN TESTING
•2)2) SAMPLE POINT NECESSARY FOR DEAERATOR STUDIES SAMPLE POINT NECESSARY FOR DEAERATOR STUDIES AND FOR AND FOR
TROUBLESHOOTING TROUBLESHOOTING OXYGEN INTRUSION OXYGEN INTRUSION THROUGH THE FEEDWATER PUMPTHROUGH THE FEEDWATER PUMP
•3)3) SAMPLE POINT FOR MONITORING IRON GOING TO THE SAMPLE POINT FOR MONITORING IRON GOING TO THE BOILERBOILER
FEEDWATER MONITORING
ECONOMIZER 3
1
2

15. 1515
INTERNAL TREATMENTINTERNAL TREATMENT

16. 1616
WATERTUBE BOILERSWATERTUBE BOILERS
WATER WALLS
SUPERHEATER
SCREEN TUBES
STEAM
DRUM
MUD
DRUM
ECONOMIZER
AIR HEATER
RISERS
DOWNCOMERS

17. 1717
EFFECT OF DEPOSITS ON EFFECT OF DEPOSITS ON
CIRCULATIONCIRCULATION
•Tubes with deposits have greater friction Tubes with deposits have greater friction
resistance to flow than clean tubes.resistance to flow than clean tubes.
•When circulation is decreased, the following When circulation is decreased, the following
can occur:can occur:
–increased depositionincreased deposition
–premature steam/water separationpremature steam/water separation
–Dry out of tube wallDry out of tube wall
–overheatingoverheating

18. 1818
U-Tube illustrates normal water circulation U-Tube illustrates normal water circulation
and steam generation in a clean circuit.and steam generation in a clean circuit.
COLD
HEAVY
WATER
LIGHT HOT
STEAM/WATER
MIXTURE
HEAT

19. 1919
U-Tube illustrates water circulation and steam U-Tube illustrates water circulation and steam
generation in the presence of deposits.generation in the presence of deposits.
LARGE STEAM
SURGE BUBBLE
HEAT

20. 2020
HIGH OR LOW BOILER WATER pH HIGH OR LOW BOILER WATER pH
CORRODES BOILER STEELCORRODES BOILER STEEL
1234567891011121314
RELATIVE
CORROSIVE
ATTACK
pH
8.5 pH12.7 pH
SAFE RANGE

21. 2121
ACID CORROSION IN A BOILER TUBEACID CORROSION IN A BOILER TUBE

22. 2222
GOUGES RESULTING FROM CAUSTIC ATTACKGOUGES RESULTING FROM CAUSTIC ATTACK

23. 2323
COORDINATED PHOSPHATE/pH COORDINATED PHOSPHATE/pH
PROGRAMSPROGRAMS
•Used Primarily in high pressure boilers to Used Primarily in high pressure boilers to
protect against caustic gougingprotect against caustic gouging
•Applicable for lower pressure boiler systems Applicable for lower pressure boiler systems
on demin quality makeupon demin quality makeup
•Caustic and acid (e.g. Na, Cl) are primary feed Caustic and acid (e.g. Na, Cl) are primary feed
water contaminantswater contaminants
•If the Iron/Copper problems exist in the If the Iron/Copper problems exist in the
system, system, Polymeric DispersantPolymeric Dispersant is is
recommended to be used.recommended to be used.

24. 2424
COORDINATED PO4/pH CONTROLCOORDINATED PO4/pH CONTROL
•Depends on pressureDepends on pressure
•Measure PO4 and pHMeasure PO4 and pH
•Control PO4 and pH by the following methodsControl PO4 and pH by the following methods
1.1. Vary internal treatment chemicals injection Vary internal treatment chemicals injection
raterate
2.2. Vary blowdownVary blowdown

25. 2525
COORDINATED pH/PHOSPHATE CONTROL
10.8
10.6
10.4
10.2
10.0
9.8
9.6
9.4
9.2
9.0
8.8
8.6
8.4
8.2
1.0 2 345678 10 15 20 30 405060
ppm Orthophosphate, as PO
4
``Free'' Caustic
Region
``Captive''
Alkalinity
Region
Vector
Control
DiagramControl Area
>2600 psi
Control Area
2001-2500 psi
Control Area
1501-2000 psi
Control Area
901-1500 psi
Control Area
<900 psi
-
CONTROL AREA
2501-2600 psi
MAXIMUM BOUNDARY 3.0:1 MOLAR RATIO
2.6:1 Na/PO
4
2.7:1 Na/PO
4
2.8:1 Na/PO
4
CONTROL BOUNDARY
2.2:1 Na/PO
4
MOLAR RATIO
BLOWDOWN MONO-SODIUM
PHOSPHATE
DI-SODIUM
PHOSPHATE
TRI-SODIUM
PHOSPHATE
CAUSTIC
pH AT
25C

26. 2626
Drum OperatingDrum Operating psig 0-300psig 0-300 301-450301-450 451-600451-600
Pressure (1) (11)Pressure (1) (11) (MPa) (0-2.07)(MPa) (0-2.07)(2.08-3.10)(2.08-3.10)(3.11-4.14)(3.11-4.14)
•BOILER WATERBOILER WATER
•Silica ppm (mg/l) SiO2Silica ppm (mg/l) SiO2 <<150150 <<9090 <<4040
•Total alkalinity ppm (mg/l)*Total alkalinity ppm (mg/l)* <350 (3)<350 (3) <300 (5)<300 (5) <250 (5)<250 (5)
•Free OH alkalinity ppm (mg/l)* (2)Free OH alkalinity ppm (mg/l)* (2) NSNS NSNS NSNS
•Specific conductance (12)Specific conductance (12)
umhos/cm (umhos/cm (S/cm) 25S/cm) 25
OO
CC
without neutralizationwithout neutralization 5400-1100 (5)5400-1100 (5)4600-900 (5)4600-900 (5)3800-800 3800-800
(5)(5)
•TOTAL DISSOLVED SOLIDS IN STEAM (9)TOTAL DISSOLVED SOLIDS IN STEAM (9)
•TDS (maximum) ppm (mg/l)TDS (maximum) ppm (mg/l) 1.0-0.21.0-0.2 1.0-0.21.0-0.2 1.0-0.21.0-0.2
1994 EDITION1994 EDITION
INDUSTRIAL WATERTUBE, HIGH DUTY, INDUSTRIAL WATERTUBE, HIGH DUTY,
PRIMARY FUEL FIRED, DRUM TYPEPRIMARY FUEL FIRED, DRUM TYPE
Makeup water percentage: Up to 100% of feedwater
Conditions: Includes superheater, turbine drives, or process restriction on
steam purity. Saturated steam purity target: See tabulated values below.

27. 2727
• 601-750601-750 751-900751-900 901-1000901-1000 1001-15001001-1500 1501-20001501-2000
•(4.15-5.17)(4.15-5.17) (5.18-6.21)(5.18-6.21) (6.22-6.89)(6.22-6.89) (6.90-10.34)(6.90-10.34) (10.35-13.79)(10.35-13.79)
•BOILER WATERBOILER WATER
• <<3030 <<2020 <<88 <<22 <<11
• <200 (3)<200 (3) <150 (3)<150 (3) <100 (3)<100 (3) NS (4)NS (4) NS (4)NS (4)
• NSNS NSNS NSNS ND (4)ND (4) ND (4)ND (4)
•1500-300 (5)1500-300 (5) 1200-200 (5)1200-200 (5) 1000-200 (5)1000-200 (5) <<150150 <<8080
•
•TOTAL DISSOLVED SOLIDS IN STEAM (9)TOTAL DISSOLVED SOLIDS IN STEAM (9)
–0.5-0.10.5-0.10.5-0.10.5-0.1 0.5-0.10.5-0.1 0.10.1 0.10.1
*as CaCO
3
NS = not specified
ND = not detectable
VAM = Use only volatile alkaline materials upstream of attemperation water source. (10)
New limit of new parameter measured with this revision.

28. 2828
STEAM PURITYSTEAM PURITY
Steam Purity Steam Purity vsvs Steam Quality Steam Quality
•Steam purity is the solid, liquid, or vaporous Steam purity is the solid, liquid, or vaporous
contaminationcontamination in the steam in the steam
•Steam quality is the measurement of Steam quality is the measurement of moisturemoisture in steam in steam
Steam Purity GuidelinesSteam Purity Guidelines
•Turbine ManufacturersTurbine Manufacturers
•Industry Professional Organizations (ASME, ABMA, etc.)Industry Professional Organizations (ASME, ABMA, etc.)
•Boiler ManufacturersBoiler Manufacturers
•OperationsOperations

29. 2929
STEAM PURITYSTEAM PURITY
Importance of Steam PurityImportance of Steam Purity
•Protect Capital InvestmentsProtect Capital Investments, such , such
as:as:
–SuperheatersSuperheaters
–TurbinesTurbines
–Steam lines and valvesSteam lines and valves
•Maintain ProductionMaintain Production
•Prevent Process ContaminationPrevent Process Contamination

30. 3030
CONDENSATE TREATMENTCONDENSATE TREATMENT

31. 3131
THE VALUE OF CONDENSATETHE VALUE OF CONDENSATE
•WATERWATER
•ENERGYENERGY
•TREATMENT COSTSTREATMENT COSTS
•RELIABILITYRELIABILITY
CONDENSATE TREATMENTCONDENSATE TREATMENT

32. 3232
CONDENSATE CORROSIONCONDENSATE CORROSION
WHY IS IT A PROBLEM?WHY IS IT A PROBLEM?
1)1)Metal Loss - FailuresMetal Loss - Failures
2)2)Corrosion ProductsCorrosion Products
GUIDELINES FOR FEEDWATER QUALITYGUIDELINES FOR FEEDWATER QUALITY
ASME (American Society of Mechanical Engineers)ASME (American Society of Mechanical Engineers)
TAG manual page 2.6-2TAG manual page 2.6-2
Boiler reference manual page 3.1-2Boiler reference manual page 3.1-2
EPRI (Electric Power Research Institute)EPRI (Electric Power Research Institute)
TAPPI (Technical Association Pulp and Paper Industry) - TAPPI (Technical Association Pulp and Paper Industry) -
FOR PAPER MILL BOILERS >900 psigFOR PAPER MILL BOILERS >900 psig

33. 3333
FEEDWATER ALKALINITY IS A SOURCE OF COFEEDWATER ALKALINITY IS A SOURCE OF CO
22 IN IN
CONDENSATECONDENSATE
IN THE BOILER :IN THE BOILER :
2HCO2HCO
33
--
CO CO
33
==
+ H + H
220 + CO0 + CO
22
COCO
33
==
CO CO
22 + 2OH + 2OH
--
STEAM
CO
2
FEEDWATER
HCO
3
-
CO
3
=
OH
-
BLOWDOWN
IN THE CONDENSATE :IN THE CONDENSATE :
COCO
22 + H + H
220 (Condensate)0 (Condensate) H H
22COCO
33 (Carbonic Acid) (Carbonic Acid)
HH
22COCO
33 HH
++
+ HCO + HCO
33
--

34. 3434
CHEMICAL CONDENSATE CHEMICAL CONDENSATE
TREATMENTTREATMENT
•Neutralizing AminesNeutralizing Amines
•Filming CompoundsFilming Compounds
•Oxygen Scavengers/PassivatorsOxygen Scavengers/Passivators

35. 3535
METHOD OF CORROSION METHOD OF CORROSION
INHIBITIONINHIBITION
CHEMICALCHEMICAL -- Neutralization of acidic Neutralization of acidic
species and elevation of pHspecies and elevation of pH
-- Scavenging of oxygenScavenging of oxygen
PHYSICALPHYSICAL -- Creation of a barrier or Creation of a barrier or
film which is impervious to film which is impervious to
oxygen, water, acidic speciesoxygen, water, acidic species

36. 3636
NEUTRALIZING AMINESNEUTRALIZING AMINES
•The neutralizing amine reaction is a simple acid/base reaction in The neutralizing amine reaction is a simple acid/base reaction in
equilibrium.equilibrium.
•One mole of a primary neutralizing amine neutralizes one mole of One mole of a primary neutralizing amine neutralizes one mole of
carbonic acid.carbonic acid.
•In the presence of carbonic acid:In the presence of carbonic acid:
R - NHR - NH
22 + H + H
22COCO
3 3 ==== R - NH R - NH
33
++
+ HCO + HCO
33
--

NEUTRALIZING AMINE + CARBONIC ACIDNEUTRALIZING AMINE + CARBONIC ACID “AMINIUM” ION + BICARBONATE“AMINIUM” ION + BICARBONATE
•In the absence of acid:In the absence of acid:
R - NHR - NH
22 = H = H
22O O ==== R - NH R - NH
33
++
+ OH + OH
--
NEUTRALIZING AMINE + WATERNEUTRALIZING AMINE + WATER “AMINIUM” ION + HYDROXIDE“AMINIUM” ION + HYDROXIDE

37. 3737
FUNDAMENTAL AMINE FUNDAMENTAL AMINE
CHARACTERISTICSCHARACTERISTICS
•Distribution RatioDistribution Ratio
•Neutralizing CapacityNeutralizing Capacity
•BasicityBasicity
•Thermal StabilityThermal Stability

38. 3838
Concentration in steam
Concentration in liquid
DR =
VAPOR
LIQUID
HIGH DISTRIBUTION
RATIO
LOW DISTRIBUTION
RATIO
DISTRIBUTION RATIOSDISTRIBUTION RATIOS

39. 3939
BASICITYBASICITY
•Measures amine’s ability to elevate pH Measures amine’s ability to elevate pH afterafter CO CO
22
is neutralized (i.e. in the absence of acid, pH >7.0)is neutralized (i.e. in the absence of acid, pH >7.0)
•Dictated by extent of amine hydrolysis in waterDictated by extent of amine hydrolysis in water
R - NHR - NH
22 + H + H
22O O R - NHR - NH
33
++
+ OH + OH
--
KK
BB = [ R - NH = [ R - NH
33
++
] [OH] [OH
--
]] [ R - NH[ R - NH
2 2 ]]

40. 4040
COOLING WATER COOLING WATER
TREATMENT PROGRAMTREATMENT PROGRAM
•Open Recirculating Cooling Water SystemOpen Recirculating Cooling Water System
•Closed Recirculating Cooling Water Closed Recirculating Cooling Water
SystemSystem
•Once Through Cooling Water SystemOnce Through Cooling Water System
TYPE OF COOLING WATER :TYPE OF COOLING WATER :

41. 4141
ONCE - THROUGH SYSTEMONCE - THROUGH SYSTEM
Cooling - Water Inlet
Heat
Load
Outlet

42. 4242
CLOSED RECIRCULATING SYSTEMCLOSED RECIRCULATING SYSTEM
To
Cooling Tower
Heat
Load
From
Cooling Tower
Makeup
Surge Tank
Heat Exchanger

43. 4343
OPEN RECIRCULATING SYSTEMOPEN RECIRCULATING SYSTEM
Evaporation
Heat
Load
Blowdown
Makeup
Recirculating Pump
Cooling
Tower

44. 4444
TYPES OF MECHANICAL COOLING TOWERSTYPES OF MECHANICAL COOLING TOWERS
Air
In
Water
In
Air
In
Air
In
Air
In
Air
In
Water
In
Forced Draft
Induced Draft
Counter Flow
Air Out
Air Out
Induced Draft
Cross - Flow
Air Out
Water InWater In

45. 4545
Cooling Tower CalculationCooling Tower Calculation
•E = (RR x E = (RR x T X f)/580 ; mT X f)/580 ; m
33
/h/h
•C = MU/BD = [I]C = MU/BD = [I]
BDBD/[I]/[I]
MUMU
•BD = E/(C – 1) ; mBD = E/(C – 1) ; m
33
/h/h
•MU = BD + E ; mMU = BD + E ; m
33
/h/h
EE = Evaporation Rate ; = Evaporation Rate ; RRRR = Recycle Rate ; = Recycle Rate ; TT = Temperature = Temperature
Range ; Range ; ff = Evaporation Factor ; = Evaporation Factor ; CC = Cycle of Concentration ; = Cycle of Concentration ;
MUMU = Make-up Rate ; = Make-up Rate ; BDBD = Blow-down Rate ; = Blow-down Rate ; II
BDBD = Ion = Ion
Concentration in Blow-down ; Concentration in Blow-down ; II
MUMU = Ion Concentration in Make-up = Ion Concentration in Make-up

46. 4646
COOLING TOWER COMPONENTSCOOLING TOWER COMPONENTS
Multi-Blade
Fan
Distribution Area
Splash
Bar Grid
And
Supports
Air Flow
Louvers
Drift Eliminators Longitudinal Partition
Air Flow
End Wall
Casing
Air Flow

47. 4747
WATER TREATMENT CONCERNS
Corrosion
Deposition
Biofouling (slime adhesion)

48. 4848
WATER TREATMENT CONCERNS
Corrosion
Deposition Biofouling
Particle Entrapment
Growth Sites

49. 4949
PROBLEM OF CORROSION AND SCALEPROBLEM OF CORROSION AND SCALE
Efficiency drop in HE
Leakage from HE
Reduction of material strength
Plugging of HE
Increased pump pressure and
reduction of flow rate
Acceleration of corrosion
CORROSION
SCALE

50. 5050
PROBLEM OF BIOFOULINGPROBLEM OF BIOFOULING
Lowered efficiency of HE
Adsorption and waste of chemicals
Deformation of tower packing
Plugging of HE
Increased pump pressure and
reduction of flow rate
Accelerated of corrosion
Slime
Adhesion
Sludge
Accumulation
Lower efficiency of Cooling Tower
Dirty appearance

51. 5151
Classic Corrosion CellClassic Corrosion Cell
Fe
+2
O
2
O
2
O
2
-
OH
-
Electron
Flow
Cathode
Anode
Fe(OH)
3
Fe(OH)
2
Electrolyte

52. 5252
Types of CorrosionTypes of Corrosion
Uniform
Localized
Macroscopic Microscopic
Other
• Microbiological
• Erosion
or

53. 5353
Uniform CorrosionUniform Corrosion
•Least damaging type of corrosionLeast damaging type of corrosion
•Cathodic and anodic sites continuouslyCathodic and anodic sites continuously
changingchanging
•Metal loss is over the entire surface areaMetal loss is over the entire surface area
•Long time before failure occursLong time before failure occurs

54. 5454
Localized CorrosionLocalized Corrosion
• Very detrimentalVery detrimental
• Metal loss is very lowMetal loss is very low
• Corrosion concentrated in one area - Corrosion concentrated in one area -
short short
time before failuretime before failure
• Can be macroscopic, microscopic or Can be macroscopic, microscopic or
microbiologicalmicrobiological

55. 5555
MACROSCOPIC CORROSION
Galvanic corrosion
Concentration cell
Pitting
Leaching

56. 5656
Galvanic CorrosionGalvanic Corrosion
•Two dissimilar metals in contact Two dissimilar metals in contact
with an electrolytewith an electrolyte
•One metal corrodes, the other is One metal corrodes, the other is
protectedprotected

57. 5757
Galvanic SeriesGalvanic Series
Magnesium
Zinc
Aluminum
Mild Steel
Cast Iron
Stainless Steel (active)
Brass
Copper
Bronze
Copper Nickel Alloys
Titanium
Stainless Steel (passive)
Graphite
Cathodic-
More easily
protected
Anodic-
More easily
corroded

58. 5858
Concentration CellConcentration Cell
•Local differences in metal-ion Local differences in metal-ion
concentration creates an electrical concentration creates an electrical
potential that accelerates corrosionpotential that accelerates corrosion
•Occurs in areas where metal-ion Occurs in areas where metal-ion
concentrations may build up and concentrations may build up and
result in a flow of electric currentresult in a flow of electric current

59. 5959
Crevice Corrosion Crevice Corrosion
Na
+
OH
-
O
2
M
+
Cl
-
M
+
M
+
M
+
M
+
O
2O
2O
2
O
2
OH
-
OH
-
OH
-
Cl
-
Cl
-
Na
+
Na
+
Na
+
O
2
e
-
e
-
e
-
e
-
e
-

60. 6060
PittingPitting
•Anodic areas on the metal surface Anodic areas on the metal surface
remain stationaryremain stationary
•Chemicals, such as halide salts and Chemicals, such as halide salts and
chlorides, are well known chlorides, are well known
pit-producers pit-producers

61. 6161
PittingPitting
Water
Iron
Tubercle
Protective Film
Pit Forming
at Small Anodes

62. 6262
LEACHING
Selective removal of one element from aSelective removal of one element from a
solid alloy by corrosionsolid alloy by corrosion
Dezincification - removal of zinc from brassDezincification - removal of zinc from brass
alloys alloys
Graphitization - removal of Fe from cast ironGraphitization - removal of Fe from cast iron
Dealuminumification - removal of Al fromDealuminumification - removal of Al from
aluminum bronzes aluminum bronzes
Examples:

63. 6363
MICROSCOPIC CORROSION
Intergranular corrosion
Transgranular corrosion
Stress corrosion cracking

64. 6464
INTERGRANULAR CORROSION
Localized corrosion occurring along the grain
boundary of a metal
Caused by impurities at grain boundaries
Areas adjacent to grain center are more anodic
than grain boundaries

65. 6565
TRANSGRANULAR CORROSION
Localized corrosion occurring across grain
boundaries
Results due to a combined mechanical action
and a corrosive environment

66. 6666
STRESS CORROSION CRACKING
Localized attack due to a combined surface
tensile stress and a corrosive environment
Corrosion can be either intergranular or
transgranular

67. 6767
EROSION CORROSION
Attack caused by the combined effect of an
erosive water (high velocity or suspended
solids) with corrosive conditions
Rate of corrosion affected by
Velocity
Turbulence
Impingement
Particulate solids

68. 6868
MICROBIOLOGICAL CORROSION
Certain forms of MB can attack metal directly
and / or indirectlyand / or indirectly
Sulfate - reducing bacteriaSulfate - reducing bacteria (SRB)
Sulfur bacteriaSulfur bacteria
Iron and manganese bacteriaIron and manganese bacteria
Film formers - bacteria, fungi, algaeFilm formers - bacteria, fungi, algae
(MICROBIALLY INFLUENCED CORROSION)

69. 6969
FACTORS AFFECTING CORROSION
pH
Conductivity
Oxygen
Temperature
Velocity

70. 7070
EFFECT OF pH ON CORROSION RATE
C
O
R
R
O
S
I
O
N

R
A
T
E
4
pH
10

71. 7171
CORROSION
POTENTIAL
FOULING
POTENTIAL
pH
pH HAS OPPOSITE EFFECT ON THE POTENTIALS FOR
CORROSION AND FOULING
0 14

72. 7272
EFFECT OF CONDUCTIVITY ON CORROSION
C
O
R
R
O
S
I
O
N

R
A
T
E
DISSOLVED SOLIDS

73. 7373
EFFECT OF VELOCITY ON CORROSIONEFFECT OF VELOCITY ON CORROSION
C
O
R
R
O
S
I
O
N

R
A
T
E
VELOCITY
Mechanical
Erosion
Oxygen
Polarization

74. 7474
TYPES OF INHIBITOR FILMS
Anodic
Cathodic
Adsorbed layer

75. 7575
ANODIC CONTROL
Stable, tenacious, iron oxide
films formed at the anodic
sites on the metal surface

76. 7676
CATHODIC CONTROL
Locally precipitated films that form at the
cathodic sites on the steel surface
Formation is driven by localized high pH
These films are more porous than the
anodic films and not as tenacious

77. 7777
ADSORBED LAYER FILMS
•Chemi-sorbed films that Chemi-sorbed films that
provide single or multiple provide single or multiple
layer protection against layer protection against
corrosioncorrosion
•Both anodic and cathodic sites Both anodic and cathodic sites
are coveredare covered

78. 7878
DEPOSITIONDEPOSITION

79. 7979
TYPES OF DEPOSITION
Scaling
Mineral Scale
Fouling
Suspended Matter
Transient Corrosion Products
Process Leaks

80. 8080
WATER - FORMED SCALE DEPOSIT MECHANISMSWATER - FORMED SCALE DEPOSIT MECHANISMS
Water Dissolved Minerals
Dissolution Solubilzation
Supersaturation
Nucleation Precipitation
Crystal Growth
Scaling

81. 8181
Mineral Scale
Can Form When:
Solubilities
Are Exceeded

82. 8282
MINERAL SCALES
SOLUBILITY
TEMPERATURE
Temperature - Major Impact on Solubility

83. 8383
COMMON COOLING SYSTEM SCALES
CaCO
CaSO
Ca (PO )
MgSiO
Al O SiO
Zn (PO )
FePO
CaO MgO 2(SiO )
SiO
3
4
234
3
2
2 2
342
4
2
3

84. 8484
CALCIUM CARBONATE
Most common scale found in cooling water
systems
Degree of scaling depends on:
Calcium hardness
Alkalinity
Total dissolved solids
pH
Temperature

85. 8585
CALCIUM CARBONATE INDICES
Langelier Saturation Index
LSI = pH
a - pH
s
where pHa = actual water pH
pHs = saturation pH
If LSI is: + scale formation is likely
scale formation should not
occur
pH = 16.58 - log(Ca) - log(M-Alk)+0.1log(TDS)
- 2.6 log (T)

86. 8686
CALCIUM CARBONATE INDICES
Ryznar Stability Index
RSI = 2pH
s - pH
a
Numerical values of:
> 7.0 indicate corrosion tendency
< 6.0 indicate scaling tendency

87. 8787
CALCIUM PHOSPHATE
Less soluble at high pH and temperature
Sources
River water
Partially treated sewage waters
Phosphate based treatment

88. 8888
SILICA
Solubility increases with increasing pH and
temperature
Dissolved silica in natural water exists in the
form of H
2SiO
3, H
2O, orthosilicic acid
Current guidelines < 200 ppm SiO
2
(molybdate reactive)

89. 8989
SILICATES
Solubility decreases with increasing pH and
temperature
Solubility affected by calcium and magnesium
concentrations

90. 9090
SILICATES
Magnesium Silicate Guidelines based on:
(ppm Mg as CaCO
3) x (ppm SiO
2)
Calcium Magnesium Silicate Guidelines:
At pH > 9.0 Solubility Product < 1 x 10
6
(ppm Ca as CaCO
3) x (ppm Mg as CaCO
3) x (ppm SiO
2)
based on:

91. 9191
7.0 7.5 8.0 8.5 9.0
pH
0
100,000
200,000
300,000
400,000
500,000
Magnesium
Silicate
Product
Magnesium Silicate Saturation IndexMagnesium Silicate Saturation Index
(Soluble field test SiO x cycles)x(Mg x cycles)(Soluble field test SiO x cycles)x(Mg x cycles)
22
Deposition Expected

92. 9292
FOULANTS FOUND IN FOULANTS FOUND IN
COOLING SYSTEMSCOOLING SYSTEMS
Mud / Silts
Organics / Oil
Dust / Dirt
Matter precipitated in bulk water
Corrosion products
Microbiological

93. 9393
DEPOSIT CONTROLDEPOSIT CONTROL
CHEMICAL MECHANICAL
PROCESS
ADJUSTMENT
REMOVALDISPERSIONINHIBITION

94. 9494
MECHANICAL
REMOVAL PROCESS ADJUSTMENT
SOFTENING
CLARIFICATION
FILTRATION
SIDE STREAM FILTRATION
CLEANING
INCREASE VELOCITY
INCREASE BLOWDOWN
EQUIPMENT DESIGN
REDUCE TEMPERATURE
pH ADJUSTMENT

95. 9595
D
E
P
O
S
I
T
I
O
N
pH
EFFECT of pH on DEPOSITIONEFFECT of pH on DEPOSITION

96. 9696
CHEMICAL
INHIBITION DISPERSION
NATURAL
POLYMERS
SYNTHETIC
POLYMER
SEQUESTRATION
CHELATION
THRESHOLD

97. 9797
TYPES OF INHIBITORS
Sequestrants or Chelants
Compounds that react with metal ions to form
soluble complexes
Fed stoichiometrically
Threshold Inhibitors
Inhibit or retard crystal growth
Fed sub-stoichiometrically

98. 9898
DISPERSANTS
Control particle size by interfering with particle
agglomeration
Adsorb on particle surfaces imparting excess
negative charges that cause the particles to repel
each other

99. 9999
BIOFOULINGBIOFOULING

100. 100100
OXIDIZING BIOCIDES
NON-OXIDIZING BIOCIDES
Indiscriminate oxidation
Specific reactions
TYPE OF BIOCIDE :

101. 101101
OXIDIZING BIOCIDES
Types
Chlorine gas
Sodium hypochlorite
Calcium hypochlorite
Chlorine dioxide
Solid halogen donors
Bromine
Ozone

102. 102102
BIOCIDAL EFFICACY
Control Sessile & Planktonic Population
Factors
Type of residual
Amount of residual
Form of residual
Contact time

103. 103103
NON-OXIDIZING BIOCIDES
MODES OF ACTION
Metabolic Inhibitors
Interrupt metabolic cycles
Enzyme poisons
Alter protein structures
Irreversibly bind to active sites

104. 104104
NON-OXIDIZING BIOCIDES
MODES OF ACTION
Surface Active Agents
Alter permeability of cell membrane
Undesirable compounds enter cell
Nutrients and intracellular materials escape

105. 105105
The Recommended Range for Control The Recommended Range for Control
Open Cooling Treatment ProgramOpen Cooling Treatment Program
ParameterParameter UnitUnit ValueValueUnitUnit
•pHpH 7.5-8.57.5-8.5
•Total HardnessTotal HardnessPpm as CaCOPpm as CaCO
33<< 450 450
•LSILSI << 2.5 2.5
•ConductivityConductivity s/cms/cm << 1500 1500
•SilicaSilica ppm SiOppm SiO
33 << 200 200
•M-AlkalinityM-Alkalinity ppm as CaCOppm as CaCO
33<< 300 300
•Organic POOrganic PO
44 ppm POppm PO
44 4.5-6.04.5-6.0
•Total IronTotal Iron ppm Feppm Fe << 1 1
•Bacteria CountBacteria CountCol./mlCol./ml << 10000 10000
•Corrosion RateCorrosion Ratempympy << 5 5

106. •Daily water analysis, performance monitoring, and
give technical support
•Install retractable corrosion probe (if necessary)
and coupon for corrosion rate analysis
•Monthly Report on the Boiler System Performance
and Chemical Consumption
•Inventory control at site to avoid product stock out
106106
ARRAD
Value Added Technical Services

107. •Supply product on-time delivery.
•Low inventory at plant site.
•Technical visit and inspection during plant start and
shut down.
•Technical training for boiler operator on subject of
water system treatment.
•We also provide equipment to support the routine
activities, as follows:
- Laboratory Instrument, e.g:
Spectrophotometer
- PPE for our personnel as our commitment
concern on HSE 107107
ARRAD
Value Added Technical Services

108. 108108
THANK YOUTHANK YOU
The Right Chemicals to Water Systems