Cooling Water Treatment 455d4r

COOLING WATER TREATMENT Advanced training course Cairo – 22 to 24 May 2005

Jean Michel Fréal-Saison

Technical Group Leader MEAGCC

Attendees Welcome to all of you to our first Regional Advanced Technical Training Course Thank you for attending this training course. We are particularly pleased to welcome our colleagues from System Technique. Attendance List.xls We which you every success in this training course.

Agenda Day 1 –22 May 2005 08:30 to 08:45 Introduction 08:45 to 09:00 Pre-training Quizz 09:00 to 10:30 Water Chemistry 10:30 to 11:00 Coffee break 11:00 to 12:30 Cooling System hydraulics 12:30 to 13:30 Lunch 13:30 to 15:00 Cooling Water Treatment 15:00 to 15:30 Coffee Break 15:30 to 17:00 Scaling and Scale control

Agenda Day 2 –23 May 2005 08:30 to 10:00 Corrosion and Inhibitors 10:00 to 10:30 Coffee break 10:30 to 12:30 Corrosion control 12:30 to 13:30 Lunch 13:30 to 15:00 Microbiological control 15:00 to 15:30 Coffee Break 15:30 to 17:00 Treatment and Product Guidelines

Agenda Day 3 –24 May 2005 08:30 to 10:30 Monitoring and control 10:30 to 11:00 Coffee break 11:00 to 12:00 Troubleshooting 12:00 to 12:30 Final Quizz 12:30 to 13:30 Lunch

Pre-Training Quizz (10 mn) Read the questions carefully. Do not extrapolate. T - F (True – False): Select the right statement A-B-C: one or more answer(s) is(are) correct

Team work Form 4 or 5 teams (4 to 5 in each team) Team A: Team B: Team C: Team D:

INDEX 1. 2. 3. 4.

Basic water chemistry Cooling systems Cooling system hydraulics Cooling water treatment programmes 1. Scale inhibition 2. Corrosion inhibition 3. Yellow metal corrosion inhibition 4. Closed system inhibitors 5. Microbiological control 6. Treatment programme design 7. Monitoring and troubleshooting

Chap 1 BASIC WATER CHEMISTRY

Basic Water Chemistry

WATER •Pure water contains one part of oxygen and two parts of hydrogen and is > COLOURLESS > ODOURLESS > TASTELESS •PHYSICAL PROPERTIES > Melting Point 0°C (32°F) > Boiling Point 100°C (212°F) > Typical Density 1 gramme / ml > Maximum Density at 4°C

Water Cycle

Atmospheric moisture Precipitation

Evaporation and Transportation from Surface Water Bodies, Land Surface and Vegetation Consumptive use

Well

Evaporation from Oceans

Stream flow to Oceans

Percolation Total Surface and Ground Water flow to Oceans

Water Table Fresh Ground Water

Ocean Saline Ground Water

WATER Water is the UNIVERSAL SOLVENT and dissolves to some degree every known substance Water will contain impurities in the form of dissolved solids, suspended solids and dissolved gasses It is essential for industry that abundant supplies are continuously available

SOURCES of WATER •Surface Water > Lower quantities of Solubilised Minerals > High amounts of Particulate Matter > Variable Organic Matter Content > Influences from Terrain and Geological Composition •Ground Water > Higher Mineral content > Less Suspended Solids > Influences from Geological Composition •Other Water Sources > Recycled / Reclaimed Water > Sea Water

Purification of Water •Suspended Solids > Clarification > Filtration •Dissolved Salts > Precipitating Softening > Ion Exchange > Reversed Osmosis > Multiple Flash Evaporators •Dissolved Gases > Degasification > Deaeration

ATMOSPHERIC GASES •The atmosphere is a mixture of gases ,the main components are Nitrogen 78 %, Oxygen 21 %, Argon 0.9 % and Carbon Dioxide 0.033 % > Other gases include Hydrogen, Helium and Neon •Nitrogen is Inert •Oxygen : > The solubility is approx.10 mg/l at ambient temperature and pressure. The solubility decreases as temperature increases.

O2 SOLUBILITY IN WATER 0

10

21

32

43

TEMPERATURE, C

54

66

77

88

99

cm3/l 16

110 121 22.9 ppm 20.0

14 8 6 4 2

10

14.3 VACUUM INCHES MERCURY

0

8

4 8

6 4

12 16 20

2

28

70

11.4 8.6 5.7 2.9

24

32 50

17.2

GAUGE PRESSURE PSI

10

12

90

110 130

150

170

TEMPERATURE, °F

0.0 190 210 230 250

ATMOSPHERIC GASES •Carbon Dioxide : The solubility goes up to 1,700 mg/l in water. CO2 + H2O H+ + HCO3 = > When Carbon Dioxide dissolves in water a WEAKLY ACIDIC solution is produced. This is commonly known as Carbonic Acid > Typical pH is 6.5 to 6.8

INDUSTRIAL GASES •Industrial gases produced by burning fossil fuels and by-products from industrial processes include Sulphur Dioxide / Trioxide, Nitrous Oxides, Hydrogen Sulphide and Ammonia SO2 + H2O SO3 + H2O

H2SO3 H2SO4

Sulphurous Acid Sulphuric Acid

INDUSTRIAL GASES •Nitrous Oxides > These include Nitrous Oxide NO Nitrogen Dioxide NO2 Dinitrogen Tetraoxide N204 •Hydrogen Sulphide H2S in H2O H+ + HSBisulphide •Ammonia NH3 + H2O

OH- + NH4+ Ammonium

DISSOLVED SALTS •Water dissolves, to some extent, all known substances. However from a water treatment point of view we are mainly concerned with the salts of Calcium, Magnesium and to a lesser extent Sodium and Potassium. •The salts of Calcium and Magnesium are known as HARDNESS salts . •In most naturally occurring waters the Calcium concentration is higher than the Magnesium concentration. In sea waters the reverse is true .

DISSOLVED SALTS •Typical Calcium and Magnesium salts are : Bicarbonates Carbonates Chlorides Sulphates Silicates

Ca(HCO3)2 CaCO3 CaCl2 CaSO4 CaSiO3

Mg(HCO3)2 MgCO3 MgCl2 MgSO4 MgSiO3

SILICA •Soluble ( Reactive ) > Form : Silicic Acid H2SiO3 > Removal :Adsorption on Coagulator Floc Strong Base Anion Exchanger Resin •Colloidal ( Non-Reactive ) > Form : Complex,High molecular weight polymeric colloid > Removal : Adsorption on Coagulator Floc > Converts to reactive silica in the boiler

UNITS OF CONCENTRATION •Dosage rates for continuous feed are expressed as mg/l on either BLOWDOWN or MAKE UP water flow for cooling systems. •Shot doses are expressed as mg/l based on SYSTEM VOLUME: > 1 ppm equals: – 1 mg / l of water – 1000 mg/m³ of water – 1 g/m³ of water – 1 kg /1000 m³ of water •In some instances solution strength is expressed as a percentage: > 1 % solution = 10,000 mg/l or 10,000 ppm

UNITS OF CONCENTRATION Parts per Million ppm = mg/l Parts per Billion ppb = µg/l Normally hardness and alkalinity are expressed as mg/l CaCO3. This allows us to calculate the concentration of the different ionic species present in any given sample Total hardness 150 ppm as CaCO3 Calcium hardness 100 ppm as CaCO3 Magnesium hardness 50 ppm as CaCO3 M-Alkalinity 80 ppm as CaCO3 Chloride 40 ppm as Cl-

UNITS OF CONCENTRATION •Total hardness and Calcium hardness are obtained by titration and therefore Magnesium hardness is determined by difference . > Total hardness 150 ppm as CaCO3 > Calcium hardness 100 ppm as CaCO3 > Magnesium hardness 50 ppm as CaCO3 > M-Alkalinity 80 ppm as CaCO3 > Alkaline hardness 80 mg/l as CaCO3 > Non-alkaline hardness (150 - 80 ) = 70 mg/l

EQUIVALENT WEIGHTS •Equivalent weight refers to the amount of an element combining with a unit weight of hydrogen. •As a rule of thumb , the molecular weight divided by the valency . > Equivalent weight of CaCO3 = 100 g > Molecular weight of CO3 = 60 g > Equivalent weight of CO3 = 60/2 = 30 g – 10ppm CaCO3 = 0.2 me CO3 > Atomic weight of Calcium = 40 g > Equivalent weight of Calcium = 40/2 = 20 g – 10ppm CaCO3 = 0.2 me Ca •Ionic balance should be calculated in milli-equivalents

Corrosion Rate Measurement •mils per year = 1/1000 inch per year •mm/y = millimetres per year > 1 mpy = 0.025 mm/y (0.0254) > 1 mm/y = 40 mpy

Other important Measurements pH Alkalinity Conductivity* Chloride Sulphate Soluble Iron (in Make Up Water) Manganese * essentially Total Dissolved Solids (TDS)

Carbon dioxide species versus pH in natural waters 100% 90%

H2CO3

Pourcentage CO2

80%

CO3--

HCO3-

70% 60%

%HCO3 -/CO3 --

50%

%H2 CO2 /HCO3 -

%HCO3 -/H2 CO2

%CO3 --/HCO3 -

40%

P alk.

30% 20%

M alk.

10% 0% 2

3

4

5

6 7 pK1=6.3 5

8 pH

9

10 11 pK2=10.3 3

12

13

14

P Alkalinity P and M ALKALINITY • P = Alkalinity - phenolphthalein alkalinity (pH=8.3) > This titration includes all the HYDROXIDE and half of the CARBONATE +

H

+

H

+ OH

-

2-

+ CO 3

H O 2 -

HCO 3

M Alkalinity P and M ALKALINITY •M Alkalinity - methyl orange alkalinity (pH=4.4) > Also known as the TOTAL ALKALINITY > This titration includes all the HYDROXYDE and all the CARBONATE and all the BICARBONATE. +

H + OH +

-

2-

CO + H O 2 2

-

CO2 + H O 2

2H + CO3 +

H2O

H + HCO3

> Other indicators used are BDH 4.5 and bromocresol green/methyl red

Group exercise 1 (15 mn) From the gr 1) Which are the species possibly present depending on the pH (OH-, CO3= , HCO3-, CO2) < 4,4 Between 4,4 and 8,3 > 8,3 2) Identify the individual above ions present and calculate their concentration for the various scenarios: pAlk = 0, pAlk < mAlk/2, pAlk = mAlk/2, pAlk > mAlk/2, pAlk = mAlk

P and M ALKALINITY P and M-Alkalinity If we consider the series carbon dioxide, bicarbonate, carbonate and hydroxide we find that only adjacent pairs can co-exist pH increase

CO 2

-

HCO3

2-

CO3

OH

-

Alkalinity P=0

HCO3

CO3

Y M

Y P

P=M P = M/2

Y M

P > M/2

Y 2(M - P)

P < M/2

Y M - 2P

OH

Y 2P

All values expressed as CaCO3

Y 2P - M

Chap 2 COOLING SYSTEMS

Cooling Systems

Once Through System Cooling Water Inlet

Heat Load Heat exchanger Outlet

Closed Recirculating System Heat Load

Once Through Cooling System

Make Up Surge Tank

Water - Water Heat Exchanger

Closed Recirculating System Heat Load

Open Evaporative Cooling System

Make Up Surge Tank

Water - Water Heat Exchanger

Open Evaporative System

Evaporation

Heat Load

Cooling Tower Make Up Blowdown

Recirculating Pump

Induced Draft Cross Flow Cooling Tower

Induced Draft Counter Flow Cooling Tower 6 Cell

Forced Draft Cooling Tower

Splash Packing Wood

Plastic

Splash Fill

Plastic Film Packing

Chap 3 COOLING SYSTEM HYDRAULICS

Cooling System Hydraulics

Evaporation Evaporation Drift D

E

W Windage

Make Up MU

RR L Leaks

P

Purge

Blowdown or Non Evaporative Losses = Purge + Windage + Drift + Leaks

LATENT HEAT OF VAPORISATION • Latent Heat of Water is 556 kcal/kg • Evaporation of 1 kg water dissipates 556 kcal • Evaporation of 1 kg water from 100 kg of the (recirculating) water or 1% of the (recirculating) water reduces temperature by 5.56 °C

EVAPORATION RATE (E) E (t/h) = RR (m³/h) x ∆ T °C x Ef 580 ∆T°C = TRC° - TSC° where : R = Return Water S = Supply Water

E = 0 ,8

RR × ∆ T 580

@ 30 °C Ef 1.0 % 0.9 %

0.8 % 0.7 % 0.6 %

I.e. 1,4% of RR at 10°C ∆T or 1% RR at 6 to 7°C de ∆T

Ef Vs. wet-bulb temperature

Cycles of Concentration Definitions Cycles of Concentration (Cy) Cy = Concentration of “X” in Recirculating Water Concentration of “X” in Make Up Water

Blowdown Rate (BD) BD(m³/h) =E(m³/h) (Cy - 1)

Make Up Rate (MU) MU(m³/h) = E(m³/h) + BD(m³/h) MU (m³/h) = BD(m³/h) x Cy or BD (m³/h) = MU (m³/h) Cy

Make Up and Blowdown Rates m3/h

1E 0

1

w n

e

do w Bl o

Ev

M

ap

5x

ak

or at io n

10x

Up

Water consumption Rates relative to Evaporation Rate

3

5 Cycles

7

9

Group Exercice #2 (15 mn) Depletion: 1) How can you establish the equation for the depletion of a species in an open system as a function of the initial concentration C0, the volume of the system V (m3) and the flow rate of the blow down b (m3/h) 2) Calculate the system half life time (CT = C0/2)

DEPLETION Depletion rate is proportional to time and to the initial level of the concerned species in the system dC = - a.C dt dC = - a.dt C C = K.e -at @ t = 0 => C = Co= K C = Co e –at a = b (blowdown) = 1 ; V (volume) (residence time) Ct = Co e -bt V

DEPLETION Ct =

-bt C° e V

[ ( )]

t = - V In Ct b C°

[ ( )]

b = - V In Ct t C°

DEPLETION

a

100

% of Initial Concentration

90 80 70 60 50 40 30 20 10 0 0

5

10

Days

Ct = C° e

15

-bt V

20

SYSTEM HALF-LIFE t = - V In Ct b

C°

= - V k Iog101 = V k Iog10 2 b

2

b

t1/2 = V(m³) x 0.6931 b(m³/h) Note : This can be approximated to

t1/2 = V x 0.7 b

Chap 4 OPEN EVAPORATIVE COOLING SYSTEM TREATMENT PROGRAMMES

Treatment Objectives The general objectives of the cooling water treatment program are: Control corrosion rate to prevent equipment failure. Prevent scale formation and deposition on heat transfer surfaces to maximise system performance Control microbiological activity and maintain system cleanliness. Allow the cooling system to operate at the optimum cycles of concentration

Scaling/corrosion as pH function %

%

100

75

75

50

50

25

25

0

0

pH

SCALING

CORROSION

100

Water Treatment Concerns Corrosion

rro s Co

sit po De

i on

Pro du cts

orr sit c

ale Sc

Un de rd ep o

a bit Ha

osi

on

sm o li tab Me of t) cts en du tri Pr o Nu t, (

Scaling

s

Particle Entrapment

Deposition

Biofouling Habitat

pH 6.8

7.8

AGGRESSIVE WATER

STRONG CORROSION INHIBITORS

GE Betz Technologies pH 6.8

7.8

DIANODIC

pH

7.8

9.0

SCALING WATER

STRONG SCALING (DCA) INHIBITORS

GE Betz Technologies pH 7.8

9.0

CONTINUUM

Chap 4.1 SCALE INHIBITION TREATMENT PROGRAMMES

Scaling in Cooling Systems CaCO3 CaSO4 Ca3(PO4)2 MgSiO3 CaO.MgO.(SiO2)2 SiO2

Al2O3 , SiO2 Zn3(PO4)2 Zn(OH)2 FePO4 Calcium phosphonate

CaF2

Insoluble material formed by oxidation of incoming soluble salts within the cooling system Fe2O3

MnO2

SCALE

Mineral Scale can form when SOLUBILITY IS EXCEEDED

FACTORS AFFECTING CALCIUM CARBONATE SCALE FORMATION • • • • •

Calcium (bicarbonate) concentration M alkalinity (bicarbonate concentration) Temperature (hottest skin temperature) pH (of the bulk water) Dissolved solids concentration (activity)

LANGELIER SATURATION INDEX 1936 Professor Langelier “Conditions at which a given water is in equilibrium with calcium carbonate”.

pHs = (pK2 - pKs) + pCa + pAlk pK2 pKs pCa pAlk

= 2° dissociation constant of CaCO3 = solubility product of CaCO3 = -log calcium concentration = -log alkalinity

LSI = pHa - pHs LSI -ve : water tends to dissolve calcium carbonate and hence the water has corrosive tendency LSI +ve : water has a calcium carbonate scaling tendency

LANGELIER SATURATION INDEX

pHs = pCa + pAlk + C

Group exercise #3 (15 mn) Calculate LSI for the following water qualities and conclude: 1) Calcium Hardness 200 mg/l CaCO3 M Alkalinity

160 mg/l CaCO3

Total Dissolved Solids 400 mg/l Temperature 60 °C pH of Cooling Water (pHa) 7.80

2) Calcium Hardness M Alkalinity

40 mg/l CaCO3

35 mg/l CaCO3

Total Dissolved Solids 120 mg/l Temperature 60 °C pH of Cooling Water (pHa) 7.10

‘C’ Scale

10°C

16°C

21°C

27°C

Example Calcium Hardness M Alkalinity Total Dissolved Solids Temperature pH of Cooling Water (pHa)

32°C

38°C

43°C

49°C

54°C

200 mg/l CaCO3 160 mg/l CaCO3 400 mg/l 60 °C 7.80

60°C

pCa

66°C 71°C 77°C 82°C 88°C 93°C

pAlk

LSI = pHa - pHs= +1.04

pCa pAlk

2.70 2.50

“C” at 60 °C Total (pHs)

1.56 6.76

‘C’ Scale

10°C

16°C

21°C

27°C

32°C

38°C

43°C

49°C

54°C

Example Calcium Hardness M Alkalinity Total Dissolved Solids Temperature pH of Cooling Water (pHa)

40 mg/l CaCO3 35 mg/l CaCO3 120 mg/l 60 °C 7.10

60°C

pCa

66°C 71°C 77°C 82°C 88°C 93°C

pAlk

LSI = pHa - pHs = -0.95

pCa pAlk

3.40 3.15

“C” at 60 °C Total (pHs)

1.50 8.05

RYZNAR STABILITY INDEX Ryznar studied the actual operating results obtained with waters of various Saturation Indices

RSI = 2pHs - pHa Ryznar Stability Index > 7.5 or 8 probability of corrosion increases >7 scaling may not occur <6 scaling tendency increases, probability of corrosion decreases

RYZNAR STABILITY INDEX RSI = 2pHs - pHa Ryznar Stability Index > 7.5 or 8 probability of corrosion increases >7 scaling may not occur <6 scaling tendency increases probability of corrosion decreases

Examples: Calcium Hardness M Alkalinity Total Dissolved Solids Temperature

200 mg/l CaCO3 160 mg/l CaCO3 400 mg/l 60 °C

pCa pAlk

pH of Cooling Water (pHa)

7.80

LSI = pHa - pHs = +1.04 SCALING

2.70 2.50

“C” at 60 °C 1.56 Total (pHs) 6.76

RSI = 2pHs - pHa = 5.72 SCALING

RYZNAR STABILITY INDEX Calcium Hardness M Alkalinity Total Dissolved Solids Temperature

40 mg/l CaCO3 35 mg/l CaCO3 120 mg/l 60 °C

pCa3.40 pAlk

3.15

“C” at 60 °C Total (pHs)

1.50 8.05

pH of Cooling Water (pHa)

7.10

LSI = pHa - pHs = -0.95 CORROSIVE RSI = 2pHs - pHa = 9.00 CORROSIVE

Cycle up software: LSI Calculation and water quality simulation Cyclup.xls

Group exercise # 4 (15 mn) 1) Using Cyclup, prepare water simulation for a cooling system with the following characteristics: Volume: 1800 m3, RR: 4000 m3/H, MU Water - pH:7.3, mAlk: 250 ppm, Ca: 230 ppm, Mg:100 ppm, SiO2: 20mg/l, Cond: 1000 µS/cm, Cl: 155mg/l, SO4: 20 mg/l Group A: Ef: 1,3, ∆T: 6°C, Max Skin T: 98°C, Max Bulk T: 90°C Group B: Ef: 1,5, ∆T: 7°C, Max Skin T: 70°C, Max Bulk T: 55°C Group C: Ef: 1,4, ∆T: 8°C, Max Skin T: 85°C, Max Bulk T: 70°C Group D: Ef: 1,5, ∆T: 6°C, Max Skin T: 90°C, Max Bulk T: 85°C 2) Comment

Ca COMECHANISM SCALE INHIBITION 3 SCALE INHIBITION • INHIBITION CHELATING (COMPLEXING) ADSORPTION CRYSTALL GROWTH INHIBITION DECREASE OF CRYSTALL GROWTH CYNETICS DISTORSION OF THE CRYSTALL DISPERSION OF PARTICLES • DISPERSION

CaCO3 SCALE INHIBITION CHEMISTRIES EDTA

• INHIBITION CHELATING (COMPLEXING) ADSORPTION CRYSTALL GROWTH INHIBITION

PHOSPHONATES AEC

DECREASE OF CRYSTALL GROWTH CYNETICS DISTORSION OF THE CRYSTALL DISPERSION OF PARTICLES

TETRAPHOSPHONATES

• DISPERSION POLYACRYLATES POLYCARBOXYLATES POLYMALEATES

Ca CO3 SCALE FORMATION MECHANISM Ca2+

+

CO32-

CaCO3

• Ca2+ ions adsorb on CaCO3 Ca2+ + •

CaCO3

INITIALISATION (adsorption and ionic interactions )

CO32- + •

Fast

CaCO3

CaCO3

Slow

CaCO3

CRYSTALL GROWTH

CaCO3 CO32- +

+ Ca2+ CaCO3

CaCO3 CaCO3

SCALE INHIBITION MECHANISMS •

ADSORPTION OF Ca2+ IONS ON CaCO3

Ca2+ + •

CaCO3

Fast

CaCO3

MODE OF ACTION OF THE DISPERSANT (Adsorption and ionic interaction)

CaCO3

CaCO3 Fast

CaCO3

Ca2+ +

+ CO3-

Very slow

Ionic effect

CaCO3

Very slow

CaCO3

Active sites blocked by the dispersant

CaCO3

POLYPHOSPHATES - Tripolyphosphate O O O NaO - P - O - P - O - P - ONa ONa

ONa

ONa

- Hexametaphosphate O O O NaO - P - O - P - O - P - ONa ONa

ONa

ONa n

- Pyrophosphate O

O

KO - P - O - P - OK OK

OK

POLYPHOSPHATES • Sensitive to hydrolysis (into oPO4 ) depending on : temperature (50 - 60°C) residence time pH in the system

PHOSPHONATES • Chelating effect Blocks the generation of CaCO3 crystalls Reduce speed of growth • Depending on the type of phosphonate Sensitivity to chlorination (oxidation) Little to no risk of Ca phosphonate precipitation CONCENTRATION (mg/l) Phosphonate

after 1/2 h

PBTC HEDP AMP

10 10 10

80 °C

40 °C

C mg/l

10 9 3

after 24 h

9 5 0 Resistance to hydrolysis

after 1/2 h

9 5 1

after 24 h

8 1 0

pH 7 : 20 mg / l de Cl2

POLYACRYLATES POLYACRYLATES - CH2 - CH - CH2 - CH n

COOH

COOH

POLYMETHACRYLATES CH3 - CH2 - C - CH2 - CH n

COOH

COOH

POLYMER SPECIFICATIONS • Ionic charge pattern (copolymers) • Size of the molecules (number of monomers) Molecular weight : 500 - 30 000 • Resistance to Hydrolysis • Specifically adsorbed • The lower the molecular weight, the better the scale inhibiting effect, Optimum mw 500 – 1500

AEC : Alkyl Epoxy Carboxylate • GE Water & Process Technologies patented technology • No Phosphorus • Only contains C, H, O • Environmental fiendly • Produced in Europe • CaCO3 inhibitor – limited dispersion capability • Formulated with HPS I

Continuum AEC

AEC : Alkyl Epoxy Carboxylate • Major technology breakthrough since phosphates have been developed 25 years ago • CaCO3 inhibition • No PHOSPHORUS • Totally resistant to Cl2 et Br2 • AEC fully compatible with soluble iron unlike HEDP • No Ca/AEC precipitate formation , no need for dispersant (HPSII), unlike Ca/HEDP • Effective to avoid scaling with Zn (OH)2, Ca F2 and Ba SO4.

How can AEC be used ? In conjunction with a polymer - as a Deposit Control Agent In conjunction with Zn, oPO4 and polymer - as a low Zn, low P corrosion inhibitor programme In conjunction with Zn and polymer - as a low Zn, non P corrosion inhibitor programme In conjunction with oPO4 - as a low P corrosion inhibitor programme

CONTINUUM AEC CONTINUUM AEC IS THE FIRST CHOICE ALKALINE PROGRAMME FOR MOVING TO AN ALKALINE PROGRAMME IN ORDER TO REDUCE OR ELIMINATE ACID

CONTINUUM AEC LATEST ADVANCED TECHNOLOGY IN CaCO3 INHIBITION LOW P / ZERO P PROGRAMMES APPLICABLE TO A WIDE RANGE OF HARDNESS

CONTINUUM AEC CONTINUUM AEC CAN OPERATE AT L.S.I. > +2.5 CONTINUUM AEC IN CERTAIN CIRCUMSTANCES CAN OPERATE WITH NO ACID FEED FOR pH CONTROL THE LOWER “P” CONTENT OF CONTINUUM AEC MAY ASSIST IN DISCHARGE COMPLIANCE

CONTINUUM AEC CONTINUUM AEC IS MORE Ca TOLERANT THAN TYPICAL PHOSPHONATE BASED PROGRAMMES CONTINUUM AEC IS MORE TOLERANT TO HALOGENS, PARTICULARLY HIGH LEVELS OF CHLORINE, THAN TYPICAL PHOSPHONATE BASED PROGRAMMES

Calcium tolerant does not form an insoluble calcium compound in high calcium / high alkalinity waters can operate at higher pH, given LSI is within upper limits - lower or no acid use - less corrosive conditions at higher pH - lower pitting tendency lower polymer “demand”

Results under “stressed” conditions High LSI - can operate at LSI > + 2.5 limit most phosphonate technology is limited - LSI up to + 2.8 and + 3.0 have been successfully treated High pH - pH up to 9.3 and 9.5 have been successfully treated

Results under “stressed” conditions High calcium - calcium up to 2,000 mg/l as CaCO3 have been successfully treated High temperature - Exchangers with skin temperatures of 80°C and 95°C have been successfully treated

Benefits of Continuum AEC CaCO3 inhibitor concentration not reduced due to reversion by halogens - do not have to “overfeed” scale inhibitor to counter reversion

Limitations of Continuum AEC LSI - Calcium - pH - Dissolved Solids - Temperature - Alkalinity Max + 2.8 Industrial Systems

Limitations of Continuum AEC Low velocity As with all treatments, deposit control (and corrosion inhibition) is difficult at low velocities < 0.7 m/s becomes more difficult < 0.5 m/s difficult < 0.3 m/s question any claims

Limitations of Continuum AEC AEC is not effective CaCO3 inhibitor at concentrations < 6 mg/l - low concentrations of AEC through dosing or control difficulties would be accompanied by low polymer (and other component) concentrations * like all other treatment products does not effectively treat systems if left in the drum or under dosed.

Limitations of Continuum AEC As with any programme - if the system is not under control or is difficult to control, the programme is difficult to control * system half-life * system pH control * system BD control * system water (MU water) variance * operational variance

Limitations of Continuum AEC As with any programme - you cannot get satisfactory results by operating all or majority limiting constraints at the constraining limits - Upper

limit of Ca, pH, LSI (Cl, SO4 conductivity), temperature

- Lower limit velocity, corrosion inhibitior, scale inhibitor, dispersant, (biocide)

Agenda Day 2 –23 May 2005 08:30 to 10:00 Corrosion and Inhibitors 10:00 to 10:30 Coffee break 10:30 to 13:00 Corrosion control 13:00 to 14:30 Lunch 14:00 to 15:00 Microbiological control 15:00 to 15:30 Coffee Break 15:30 to 17:00 Treatment and Product Guidelines Pretraining Quizz CWT Corrected.pdf

Chap 4.2 CORROSION INHIBITION TREATMENT PROGRAMMES

Key Technology Milestones ‘78-81

‘81-84 1988 ‘89-91

Betz 2020 copolymer patented Dianodic II launched Heavy Metal Elimination (CrO4) Modify 2020 -improve stability/performance High Cycles & High pH Extension Introduction HPS-I Becomes Industry Standard HPS I & HPS-II for Full pH Spectrum

Key Technology Milestones ‘91-94 ‘94-98

‘99-01 ‘01-02 ‘03

Develop AEC, only non-PO4 scale inhibitor Develop HRA (halogen resistant azole) Launch Dianodic PLUS family of treatments – Halogen Stable HPS I, TEMPS, CAPS polymer package Launch Continuum AEC – Halogen Stable Development of 4th generation polymer Launch of APES

Corrosion •Corrosion is the result of two semi-reactions > Anode reaction Electrons are lost by metals (reducing agent), which are therefore oxidized Metals corrode and solubilize: Fe 2+, Cu +, Al 3+ > Cathode reaction Electrons are gained by the oxidant, which is reduced, transfer requires electrolyte (conductivity) O2, H+ are usual oxidants in aqueous environment OH- and H2 are the reduced forms.

Units of Corrosion Rate mils per year = 1/1000 inch per year mm/y = millimetres per year 1 mpy = 0.025 mm/y 1 mm/y = 40 mpy < 4 mpy < 3 mpy < 2 mpy < 1 mpy

0.1 mm/y 0.075 mm/y 0.05 mm/y 0.025 mm/y

Generally regarded as acceptable Good Very good Excellent

Pitting

Pitting at a break in the protective film

Pitting and Tuberculation Tubercule

Sand Grain Tuberculation

Fouling by Corrosion Products

CORROSION Domain of stability for iron and iron oxides at 25°C Fe, Fe(OH) 2, Fe(OH) 3

E (V) 1.2

Fe 3+

1.0 0.8 0.6

Fe (OH) 3

0.4 0.2

E = 1.23 - 0.059 * pH

Fe ++

0 - 0.2 - 0.4

Fe(OH) 2

- 0.6 - 0.8

E = - 0.059 * pH

Fe

- 1.0

FeOOH -

- 1.2 - 1.4 0

1

2

3

4

5

6

7

8

9 10 11 12 13 14 pH

CORROSION Domain of stability for iron and iron oxides at 25°C Fe, Fe3O4

E (V)

, Fe2O 3

1.2

3+ 1.0 Fe 0.8 0.6 0.4

E = 1.23 - 0.059 * pH

Fe2O3

0.2

Fe ++

0 - 0.2 - 0.4

Fe3O4

- 0.6 - 0.8

E = - 0.059 * pH

Fe

- 1.0 - 1.2 - 1.4

0

1

2

3

4

5

6

7

8

9 10 11 12 13 14 pH

Classic Iron Corrosion Cell

Anode reaction

Fe0

Cathode reaction

O2 + 2H2O + 4eFe++ + eFe++ + 2OHFe(OH)2 4Fe(OH)2 + O2 + 2H2O 4Fe(OH)3

4OH-

TYPES DE CORROSION Uniform Corrosion

chemical, electrochemical

Galvanic Corrosion

bi-metallic

Crevice Corrosion /pitting

electrochemical differential aeration chemical

Intergranular Corrosion

attack at the grain ts

Selective De-metallisation

loss of one metal in an alloy

Erosion Corrosion

mechanical

Stress corrosion cracking

stress + agressivity du milieu

(Hydrogen) (Bacterial)

GALVANIC CORROSION When there is an electrochemical potential difference beween two metals immersed in an electrolyte When these metals are in (or if there is an electrical connection), a corrosion cell is created ¾ The more noble metal is the cathode ¾ The less noble metal is the anode The more noble metal is protected, more than in the absence of (cathodic protection) The less noble metal is corroded (anode)

GALVANIC CORROSION

Electropositivity Scale

The corrosion rate will be lower, as the location is more remote end the conductivity is lower The corrosion rate will be very high id the ratio between the surface area of the cathode to the anode is high. (Current density) The most frequent galvanic corrosions: > Steel/Copper > Steel/SS > Al/Steel > Al/SS > Al/Copper Galvanic corrosion requires > A between 2 different metals > An electrolyte (ambient humidity can be enough)

The less noble

Na Mg Al/Zn Fe Sn Cu SS Mn Ag Au

The more noble

Pt

GALVANIC CORROSION There is a risk for having galvanic corrosion when copper corrosion products deposit on mild teel Cu 2+ + 2e − → Cu Fe → Fe 2+ + 2e − CuO

MS

GALVANIC CORROSION

DIFFERENTIAL AERATION CORROSION The electrochemical potential of a metal is in water is driven by the oxygen concentration: O2 + 2e- + H2O ⇒ 2OHE = E°O

-+ 0.06/2 * log [ 2 / OH

p(O2) / (OH-)2 ]

The area under the deposit contains less oxygen than the one at the surface in the vicinity (p(O2) under deposit < p(O2) outside deposit), Therefore the electrochemical potential under the deposit is lower. A corrosion cell is created where the anodic part is under the deposit d (lower potential) Any deposit (organic or inorganic) can generate this process and create under deposit corrosion.

PITTING CORROSION Very localised corrosion The most dangerous Type of corrosion > Difficult to detect: the metal loss is very limited > Damageable: lead to heat exchanger leakages A pit is a very active anodic zone The corrosion process is identical to the one for crevice corrosion. The pit protects cathodicly the bulk of the metal surface. The reaction can start due to: > Defect in the metal > Erosion

EROSION CORROSION Mechanical attack due to: > Solids > Too high fluid velocity > Water dropplets (fan in cooling towers) > Cavitation Can be easily identified because there is a visible pattern (like waves) and the metal surface is clean. All metals can be subject to erosion corrosion. The most sensitive parts are elbows, T pieces, valves, pumps, eductors and spraying equipments…

EROSION CORROSION

Case history: Metallurgical Investigations Sample 2

Sample 3

Sample 1 Filtered water collection line

Backwash inlet line 8

Backwash inlet line 8 (after cleaning)

Under deposit corrosion Biological (SRB) corrosion pit

Visual Investigations

Filtered water collection line

Flow restriction

Under Deposit Corrosion

Erosion Corrosion

Welding

ANAEROBIC ZONE

Biological Corrosion

O2 migration

Filtered water collection line

ARAETED ZONE

Visual Investigations Filtered water collection line Flow restriction

SRB corrosion pit

Water flow Growing colonies ANAEROBIC ZONE

Welding Deposition Pipe wall

Water flow Erosion corrosion

ARAETED ZONE

Causes for corrosion Deposition Æ underdeposit (supply lines) Erosion Æ on elbows weldings for turbulent flow Microbiological Æ stagnant anaerobic conditions (little access for biocides) Favoured by geometry Uneven throughout the filter lines Galvanic corrosion? Deposition on the top caused by grease released under stagnant conditions?

Causes for corrosion Geometry (contd) Extended volume of stagnant water in the back wash/air scour line Aerobic/anaerobic conditions possible in the same piping section (underdeposit corrosion) Long intervals between back wash operations Valve/elbow/welding configuration

CORROSION INHIBITORS General mechanism of corrosion inhibitors IVATING FILM > ANODIC INHIBITION > LOW FOULING TENDENCY > RESISTANCE TO pH FLUCTUATIONS (REMANENCE) > VERY THIN ( ~ 100 A°) PRECIPITATING FILM > CATHODIC INHIBITION > REDUCE PITTING > REQUIRES ACCURATE pH CONTROL ADSORBED FILM(ORGANIC) > PROTECTION FOR SPECIFIC METALLURGIES

ANODIC INHIBITION MECHANISM IVATING FILM – ANODIC INHIBITION

METAL

22--

CrO CrO44

MoO4 NO2

2-

hc

-

3-

PO4 hc Na3SiO4 Poly PO4 hc

INHIBITORS CHROMATES CrO42ANODIC INHIBITOR NO OXYGEN NEEDED (STRONG OXIDANT) BANNED DUE TO TOXICITY HIGH CONCENTRATION IF USED ON ITS OWN SENSITIVE TO REDUCING AGENTS

INHIBITORS NITRITES NO2ANODIC INHIBITOR OXYGEN NOT NEEDED, EVEN NOT SUITABLE HIGH DOSE RATE REQUIRED POSSIBLE BIODEGRADATION FOR CLOSED SYSTEMS ONLY

INHIBITORS SILICATES ANODIC INHIBITORS ENVIRONMENTAL FRIENDLY LONG TIME TO ESTABLISH PROTECTION OXYGEN NOT NECESSARY BUT HIGHER DOSAGE IF NO O2

INHIBITORS HIGH CONCENTRATION ORTHOPHOSPHATES oPO43- > 10 ppm ANODIC INHIBITOR OXYGENE NEEDED OXIDES FILM IVATION Ca PHOSPHATES DISPERSANT NECESSARY NEUTRAL pH CONTROL

INHIBITORS HIGH CONCENTRATION MOLYBDATES MoO4 > 200 ppm ANODIC INHIBITOR OXYGENE OR OXYDANT NEEDED ENVIRONMENTAL FRIENDLY SENSITIVE TO CHLORIDES HIGH DOSE RATE (>200 ppm) pH FLEXIBILITY FOR CLOSED SYSTEMS ONLY

INHIBITORS ORGANIC PHOSPHONATES (HEDP, AMP)

OH OH OH HO

ANODIC INHIBITOR OXYGENE NEEDED DOSE RATE CRITICAL (>4,5 ppm) RISK OF PRECIPITATION HIGH pH

P

C

P

O

CH3 O HEDP OH CH2

P

OH

O OH

N

CH2

P

OH

O OH CH2

P O

AMP

OH

OH

INHIBITION CATHODIC MECHANISM POROUS

PRECIPITATING FILM - CATHODIC INHIBITION

METAL

CaCO3 Ca3 (PO4)2 POLY PO4 ZINC

INHIBITORS ZINC Zn2+ > 1,5 ppm CATHODIC INHIBITOR EFFECTIVE AT LOW CONCENTRATION (>1,5 ppm) USED IN COMBINATION WITH OTHER INHIBITORS LIMITED LEVEL FOR DISCHARGE DEPOSITION

INHIBITORS LOW CONCENTRATION ORTHOPHOSPHATES 0 < oPO43- < 10 ppm CATHODIC INHIBITOR CALCIUM PHOSPHATE FILM RISK OF FOULING ALKALINE pH CONTROL

INHIBITORS POLYPHOSPHATES > 2ppm

O

O

KO - P - O - P - OK OK

OK

CATHODIC INHIBITOR pyrophosphate FILM FORMATION NEUTRAL OR ALKALINE pH CONTROL POSSIBLE REVERSION TO ORTHOPHOSPHATES (temperature, residence time)

INHIBITORS LOW CONCENTRATION MOLYBDATES 5 < MoO4 < 20 ppm NOT ACTING AS ANODIC INHIBITOR SYNERGY WITH CATHODIC INHIBITORS FILM STABILIZATION: > Fe3+/MoO4,, Zn3(OH)2(MoO4)2, Zn2(OH)2MoO4, Zn2OHPO4/MoO4 ANTIPITTING: > Transformation MoO42- Î Mo70244-/Mo8O284- Î PO4 > Phosphomolybdic acid (H3PO4, 12 MoO3) Î precipitation (polarization of the anode)

PHOSPHATE INHIBITORS

HC Orthophosphate High Concentration Primarily anodic inhibitor ive iron oxide film Requires calcium phosphate inhibitor Neutral pH control range

Neutral pH phosphate treatment Introduced 1979 10-20 mg/l orthophosphate 2 - 5 mg/l polyphosphate Calcium Phosphate Inhibitor (Copolymer) Calcium Carbonate Inhibitor (HEDP) pH 7 - 8

ivation 80 %

ANODE

Fe0 + oPO4

Fe3O4

O2 Precipitation

20 %

CATHODE

Ca + CO3 Ca + oPO4 Ca + pPO4

CaCO3 Ca3(PO4)2 Ca(pPO4)

DIANODIC CHROMATE LIKE PERFORMANCE HAS BECOME AN INDUSTRIAL STANDARD IN MANY PARTS OF THE WORLD APPLICABLE TO MANY VARIED SYSTEMS AND WATER CHEMISTRIES MORE THAN TWO DECADES OF EXPERIENCE

DIANODIC FLEXIBLE, VERSATILE, FORGIVING TREATMENT APPLICABLE TO A WIDE RANGE OF HARDNESS EASY AND SIMPLE TO MONITOR AND CONTROL

DIANODIC OPERATES AT pH 6.8 to 7.8 MOST APPLICATIONS REQUIRE pH CONTROL FOR SYSTEMS CONTAINING YELLOW METALS REQUIRES INCLUSION OF AN AZOLE

DIANODIC Components ORTHOPHOSPHATE (high concentration) CORROSION INHIBITOR Predominantly Anodic inhibitor

DIANODIC Components POLYPHOSPHATE CORROSION INHIBITOR Cathodic inhibitor Useful as an inhibitor against pitting

DIANODIC Components CALCIUM PHOSPHATE INHIBITOR > POLYMER HPS I Superior calcium phosphate inhibitor and dispersant for iron and suspended solids CALCIUM CARBONATE INHIBITOR HEDP/CAPS DISPERSANT

HPS I vs. Polymer dispersant Calcium Phosphate 100

% Inhibition BetzDearborn HPS I copolymer

80 60

Polymer Dispersant

40

AMP 20 0

Pol. an. 0

5

10

HEDP 20

Active concentration (ppm)

40

HPS I vs. Polymer dispersant Calcium Phosphate

Turbidity (NTU's)

1 0.8

High Temp

0.6 0.4 0.2 0 HPS-I

Polymer dispersant

HPS I vs. Polymer dispersant

Turbidity (NTU's)

12 Iron

10 8 6 4 2 0 HPS-I

Polymer dispersant

DIANODIC Components TTA/HRA YELLOW METAL CORROSION INHIBITOR > HRA is a GE Betz patented Halogen Resistant Azole

DIANODIC Programme Mechanism Anode

80%

Cathode

20%

Fe0 + oPO4

Ca + oPO4 Ca + pPO4

ive Iron Oxide layer (mainly magnetite)

Ca3(PO4)3 Ca polyphosphate

CONTINUUM

CONTINUUM CONTINUUM AT AT L.S.I.< +2.5

CONTINUUM CONTINUUM AEC AEC L.S.I.< +2.8 (+3.0)

CONTINUUM AT AN EXTENSION OF DIANODIC TECHNOLOGY TO ALKALINE pH FOR LOW CALCIUM WATERS AND pH UP TO 8.2, DIANODIC PHOSPHATE LEVELS ARE USED AND POLYPHOSPHATE INCLUDED FOR HIGHER CALCIUM WATERS THE PREDOMINANT CORROSION INHIBITOR IS BASED ON PHOSPHONATE AND CaCO3

CONTINUUM AT FOR HIGHER CALCIUM WATERS ORTHOPHOSPHATE IS PROGRESSIVELY REDUCED AS CALCIUM and / or pH INCREASES PROGRAMMES WITH NO ORTHOPHOSPHATE, ONLY ORGANIC PHOSPHATE, ARE AVAILABLE PROGRAMMES CONTAINING MOLYBDATE ARE AVAILABLE

CONTINUUM AT OPERATES AT pH 7.8 to 9 SOME APPLICATIONS MAY STILL REQUIRE pH CONTROL FOR SYSTEMS CONTAINING YELLOW METALS REQUIRES INCLUSION OF AN AZOLE

LC Orthophosphate Low Concentration Primarily cathodic inhibitor Requires calcium hardness Calcium phosphate formation at the cathode Alkaline pH control range

Alkaline pH phosphate treatment 2 - 10 mg/l total inorganic PO4 Calcium Carbonate Inhibitor (4 - 10 mg/l HEDP) pH = 8.0 - 9.0

ivation 20 %

ANODE

Fe0 + oPO4

Fe3O4

Precipitation 80 %

CATHODE

Ca + CO3 Ca + oPO4 Ca + pPO4

CaCO3 Ca3(PO4)2 Ca(pPO4)

Ca + HEDP

CaHEDP

CONTINUUM AT Components ORTHOPHOSPHATE CORROSION INHIBITOR Anodic and Cathodic inhibitor Predominantly Anodic at Low Hardness and Low Range pH Cathodic at High Hardness and High range pH

CONTINUUM AT Components POLYPHOSPHATE CORROSION INHIBITOR Cathodic inhibitor Only included in programmes for low hardness and pH up to 8.2 Useful as an inhibitor against pitting

Organic Phosphates Phosphonates considered both anodic and cathodic Alkaline pH control range

Organic phosphate treatment 1980s 5 - 10 mg/l organic phosphate Calcium Carbonate Inhibitor (Phosphonate) Calcium Phosphonate Inhibitor (Copolymer) pH 8.0 - 9.0

ivation 30 %

Fe0

ANODE

ive Film

Organic PO4

Precipitation 70 %

CATHODE

Ca + CO3 Ca + Phosphonate

CaCO3 Ca (Phosphonate)

CONTINUUM AT Components HEDP CORROSION INHIBITOR at concentrations above 4.5 mg/l PO4 CALCIUM CARBONATE INHIBITOR

CONTINUUM AT Components CALCIUM PHOSPHATE INHIBITOR > POLYMER HPS I Superior calcium phosphate inhibitor and dispersant for iron and suspended solids DISPERSANT CALCIUM PHOSPHONATE INHIBITOR CALCIUM CARBONATE INHIBITOR

CONTINUUM AT Components TTA YELLOW METAL CORROSION INHIBITOR

CONTINUUM AT Programme Mechanism Anode

(60%)

Cathode (40%)

Fe0 + HEDP ive Film Other anodic inhibitors if included oPO4 MoO4

Ca + oPO4 Ca + CO3 Ca + HEDP

Ca3(PO4)3 CaCO3 Ca phosphonate

Alkaline AEC phosphate treatment 4 - 10 mg/l total inorganic PO4 Calcium Carbonate Inhibitor (AEC) Calcium Phosphate Inhibitor (Copolymer) pH = 8.0 - 9.5

ivation 20 %

ANODE

Fe0 + oPO4

Fe3O4

Precipitation 80 %

CATHODE

Ca + CO3 Ca + oPO4

CaCO3 Ca3(PO4)2

CONTINUUM AEC Components ORTHOPHOSPHATE CORROSION INHIBITOR Anodic and Cathodic inhibitor Predominantly Anodic at Low Hardness and Low Range pH Cathodic at High Hardness and High range pH

CONTINUUM AEC Components DTPMP CORROSION INHIBITOR Primarily as a source of oPO4 in halogenated systems (included for formulation reasons) It can be a corrosion inhibitor in it’s own right

CONTINUUM AEC Components AEC CALCIUM CARBONATE INHIBITOR Non Phosphorous, non Phosphonate Calcium Carbonate Inhibitor Tolerant to high Chlorine concentrations High Calcium tolerance

CONTINUUM AEC Components CALCIUM PHOSPHATE INHIBITOR POLYMER HPS I Superior calcium phosphate inhibitor and dispersant for iron and suspended solids DISPERSANT

CONTINUUM AEC Components HRA YELLOW METAL CORROSION INHIBITOR HRA is a GE Water & Process Technologies patented Halogen Resistant Azole

CONTINUUM AEC Components MOLYBDATE TRACER Concentrations typically too low to be an effective corrosion inhibitor

CONTINUUM AEC Programme Mechanism Anode

Cathode

Programme is mainly cathodic inhibition Other anodic inhibitors if included MoO4

Ca + oPO4 Ca + CO3

Ca3(PO4)3 CaCO3

PHOSPHONATE INHIBITORS Organic phosphate based programmes are often supplemented with other carbon steel corrosion inhibitors Orthophosphate Zinc Molybdate

CONTINUUM AEC How much PO4 is required ? - depends on Ca and pH How much AEC is required ? - 6 to 8 mg/l active for CaCO3 inhibition How much polymer is required ? - depends on Ca and pH and PO4

CONTINUUM AEC Various ratios of polymer to AEC required to cover a range of conditions: – – – –

100 to 1,200 mg/l Ca pH (7.0) 7.8 to 9.5 (0) 2 to 8 (20) mg/l oPO4 (top off: 0.5 to 2.5 mg/l Zn)

Benefits of CONTINUUM AEC Benefits of Continuum AEC > Wide range of waters and systems can be treated > Wide range of programmes or approaches available > Wide range of products to cater for the wide range of applications, waters and approaches

Limitations of Continuum AEC High Fe High suspended solids > Create additional polymer demand which may be accomodated with higher polymer concentrations up to a given limit which depends on system design and operation

Comparative Phosphates Programme Guidelines DIANODIC II

CONTINUUM AT

pH

(6.8) 7.0 - 7.8

(> 7.8) 8.2 - 9.0

Calcium

(35) 100 - 1200

(75) 100 - 1200

(100) 250 - 1200

mg/l CaCO3

max LSI

N/A

+ 2.5

+ 2.8 + 3.0

Industrial Systems Low Heat, High Flow

max t °C

65 °C

60 °C

70 °C

Depends on exchanger and velocity

Iron

< 3 mg/l Fe

< 5 mg/l Fe

< 10 mg/l Fe

Theoretical cycled MU mg/l Fe

Reactive Silica

< 200 mg/l SiO2

< 200 mg/l SiO2

< 200 mg/l SiO2

max SiO2 defined by MgSiO2 CaMgSiO2

Conductivity < 6000 µS cm-1

CONTINUUM AEC (> 7.8) 8.2 - 9.0 (9.5) LSI MgSiO2 CaMgSiO2

Chloride < 1500 mg/l Cl

Sulphate < 2500 mg/l SO4

PHOSPHATE PROGRAMMES

Comparative Phosphates Programme Guidelines DIANODIC II

CONTINUUM AT

CONTINUUM AEC

Filtered oPO4

10 - 17 (30)

0 - 12 (15)

4 - 7 (10)

pPO4

(0) 2 - 6 (8)

0-2

Typically pyro PO4

(0) 1.5 - 2.5

(1.5) 4.5 - 6.5 (7.5)

Diphosphonate

Phosphonate as PO4 AEC

0.2 micron filter

0-6

Pentaphosphonate

6 - 8 (15)

6 mg/l AEC MINIMUM

HPS I

(17) 20 - 90 (>90)

(30) 40 - 90 (>90)

30 - 70

Ca, PO4 pH Demand

Azole

0-3

0-3

0-3

Typically TTA

Zinc

0 (up to 2.5 top off)

0

Molybdate

0 (- 8)

0-8

0 ( 0.5 - 2.5 Zn AEC) Zn AEC may need PO4 MoO4 typically used as 0-3 a tracer if < 5 mg/l MoO4

ALKALINE ZINC AND ZINC PHOSPHATE INHIBITORS

Zinc Programmes Cathodic inhibitor Used on its own or in conjunction with phosphate Neutral to alkaline control range Some potential discharge concerns

ZINC BASED PROGRAMMES ZINC BASED > Neutral to alkaline pH programme > Predominantly cathodic inhibition

ZINC BASED PROGRAMMES PRECIPITATING PROGRAMME > ZINC PHOSPHATE DOES NOT DEPEND UPON CALCIUM FOR FILM FORMATION > FILM FORMATION A FUNCTION OF ZINC SOLUBILITY WITH pH > POLYMERS CONTROL POTENTIAL FOR BULK WATER PRECIPITATION OF ZINC AND CALCIUM PHOSPHATE

ZINC PHOSPHATE TREATMENT 2 - 5 mg/L Zn 3 - 10 mg/L total inorganic PO4 [Zinc Phosphate Inhibitor (Copolymer)] pH 7.0 - 8.5

ivation 10 %

Fe0

ANODE

Fe3O4

O2 / PO4 Precipitation

90 %

CATHODE

Zn + oPO4 Ca + oPO4

Zn3(PO4)2 Ca3(PO4)2

ZINC PHOSPHATE TREATMENT Components ZINC CORROSION INHIBITOR > Cathodic Inhibitor

ZINC PHOSPHATE TREATMENT Components ORTHOPHOSPHATE CORROSION INHIBITOR > Cathodic inhibitor

ZINC PHOSPHATE TREATMENT Programme Mechanism Anode

Cathode

Programme is mainly cathodic inhibition Anodic inhibiton by PO4 depending upom calcium hardness and pH range or by HEDP or AMP if included

Ca + oPO4

Ca3(PO4)3

Zn + OH

Zn(OH)2

Ca + CO3 Zn + PO4 Ca + HEDP/AMP

CaCO3 Zn2(PO4)3 Ca phosphonate

ZINC ORGANIC TREATMENT 1 - 4 mg/L Zn 5 - 10 mg/L Organic Phosphate [Zinc Phosphate Inhibitor (Copolymer)] pH 8 - 9

ivation 30 %

Fe0

ANODE

ive Film

Organic PO4

Precipitation 70 %

CATHODE

Ca + CO3 Ca + Phosphonate Zn + OH4

CaCO3 Ca (Phosphonate) Zn(OH)2

ZINC ORGANIC TREATMENT Components HEDP and AMP CALCIUM CARBONATE INHIBITOR CORROSION INHIBITOR > at concentrations above 4.5 mg/l PO4

ZINC ORGANIC TREATMENT Components POLYMER (HPS II/HPS I) > > > > >

INHIBITOR FOR CALCIUM PHOSPHATE ZINC HYDROXIDE & PHOSPHATE CALCIUM PHOSPHONATE CALCIUM CARBONATE

> DISPERSANT FOR > Iron and suspended solids

ZINC ORGANIC TREATMENT Programme Mechanism (Alkaline Zinc) Anode

Cathode

Fe0 + HEDP

Zn + OH Ca + CO3 Ca + HEDP

ive Film

Zn(OH)2 CaCO3 Ca phosphonate

Low Hardness Waters Calcium < 100 mg/l CaCO3 difficult to treat effectively particularly if Cl and/or SO4 is high > lack of cathodic inhibition – pitting > approaches – high PO4 – Zn3(PO4)2 or Zn (top off) – high MoO4 – Silicate – Nitrite • Microbiological control problems

Molybdate Programmes Primarily an anodic inhibitor Used at high levels in closed systems Used at low levels in open systems Neutral to alkaline control range Does not require hardness Requires oxygen Low toxicity

MOLYBDATE TREATMENT 5 - 10 mg/L MoO4 5 - 10 mg/L phosphonate Calcium Carbonate Inhibitor (Phosphonate and PMA) pH 8 - 9

ivation 30 %

ANODE

Fe0

+ MoO4

O2

Fe3O4 - MoO4

Organic PO4

Precipitation 70 %

CATHODE

Ca + CO3 Ca + Phosphonate

CaCO3 Ca (Phosphonate)

Adsorbed Layer Films Chemi-sorbed films that provide single or multiple layer protection against corrosion Both anodic and cathodic sites are covered.

Silicate Adsorbed film Slow development for protection Does not require hardness Environmentally acceptable.

SILICATE TREATMENT 20 - 100 mg/L SiO2 pH 7.5 - 8.5

ivation 100 %

ANODE

Fe0 + SiO3

Fe3O4 - SiO3 Fe

CATHODE

Chap 4.3 YELLOW METAL CORROSION INHIBITION TREATMENT PROGRAMMES

Yellow Metal Corrosion Inhibition

COPPER CORROSION Domain of stability of Copper and Copper Oxides at 25°C Cu, Cu2O, CuO

E (V) 1.2 1.0 0.8

Cu++

0.6

CuO

0.4 0.2

Cu2O

0 - 0.2

E = 1.23 - 0.059 * pH HCuO2-

Cu

- 0.4 - 0.6 E = - 0.059 * pH

- 0.8 - 1.0 - 1.2 - 1.4 0

1

2

3

4

5

6

7

8

9 10 11 12 13 14 pH

COPPER CORROSION Aggravating factors are : > pH – In any case it should be >7 – The best range is between pH 8 and pH 8.5 > Oxidants : Copper is very sentitive to strong oxidants (hypochlorite, H2O2, bromine) > High level of chlorides (less sentive than SS however) > H2S, CN, NH3 > Stagnancy (or low water velocity)

Inhibition of Yellow Metals by Azoles Cupric Oxide Cuprous Oxide Copper Metal

Uninhibited CuI / Azole Inhibitor Film Cuprous Oxide Copper Metal

Inhibited

CU Corrosion inhibition Copper oxide film formation (duplex film)

O2 2 CUPRIC OXIDE ( NOT PROTECTIVE ) CUPROUS OXIDE ( ADHERENT AND PROTECTIVE )

1

COPPER METALLURGY

The corrosion rate is controlled by the equilibrium between 1 and 2

Cu Corrosion inhibition Cupper protection mechanism Corrosive agent

Cu (I) / INHIBITOR Complex CUPROUS OXIDE ( ADHERENT AND PROTECTIVE )

CUPPER METALLURGY

Cu (I) / INHIBITOR complex controls oxidation of Cu (I) into Cu (II) ( the real protective agent is the complex and not the filming inhibitor ).

Azoles (TTA, BZT, MBT) z

z

z

Adsorbed films Used primarily for copper / copper alloy protection S Fed on a continuous basis

SH N

N N N H Benzotriazole (BZT)

Mercaptobenzothiazole (MBT)

CH3 N

CH3

N

N N H 4-methylbenzotriazole (TTA)

N N H 5-methylbenzotriazole (TTA)

Azoles (bBZT) z

Fed on an intermittent basis C4H9

N N N H

Butylbenzotriazole (bBZT)

Yellow Metal Corrosion Inhibition R N N Azole

N H

Deprotonation R

H+ N N N

Azole Anion

-

Yellow Metal Corrosion Inhibition Bridging by Copper Ions

N

N N

Cu

N

N N

Cu

N

N N

Cu

Cu

Chemical Structure of Azoles R N N Y

N H

Halogen Resistant Azole (HRA)

Persistency of Azole Films Copper Corrosion Rate (m m /y)

0.008

BZT 0.006

TTA 0.004

HRA bBZT

0.002

0.000 0

5

10

15

20 Days

25

30

35

40

Chap 4.4 CLOSED SYSTEM CORROSION INHIBITION TREATMENT PROGRAMMES

“Dangerous” Inhibitors Anodic inhibition only

A

2e

C

Pitting 2 mpy

A

2e

C

Pitting 2 mpy Overall corrosion 4 mpy

“Dangerous” Inhibitors Anodic inhibition only

C

Pitting 0 mpy

C

Pitting 0 mpy Overall corrosion 0 mpy

“Dangerous” Inhibitors Anodic inhibition only

C

Pitting 0 mpy

C

Pitting 4 mpy

2e

A

2e

Overall corrosion 4 mpy

Closed System Inhibitors Nitrite based CorrShield NT Series

Nitrite Promotes anodic films No oxygen required - generally used in closed systems Used at high levels Susceptible to biodegradation Affected by Halogens

NITRITE TREATMENT 600 - 1200 mg/L NO2 pH 7 - 9.5

ivation 100 %

ANODE

CATHODE

Fe0 + NO2

Fe3O4

CorrShield NT Series mg/l NT4201

NO2

3000 - 6000 600 - 1200 TTA

NT4290 20000 - 40000 600 - 1200 NT4292

2250 - 4500 600 - 1200

NT4293 8000 - 16000 600 - 1200 MBTZ PAA NO3

SiO2 Borate

Compatibility All NT products are compatible with Alcohol and Glycol NT4293 is not compatible with NaCl or CaCl2 Brines Others are compatible with NaCl and CaCl2 Brines If Al present keep pH < 8

Closed System Inhibitors Molybdate based CorrShield MD Series

MOLYBDATE TREATMENT 200 - 300 mg/L MoO4 Calcium Carbonate Inhibitor (PAA) pH 7.5 - 9.5

ivation 100 %

ANODE

Fe0 + MoO4

Fe3O4 - MoO4 O2

CATHODE

Molybdate Promotes anodic films Requires some oxygen Used at high levels Requires some oxygen Used at high levels

CorrShield MD Series mg/l

MoO4

NO2

MD4100

2400 - 3600

200 - 300 160 - 240 PAA

TTA

MD4101

2300 - 4600

100 - 200

PAA

TTA Morpholine

MD4103

1000 - 3000

200 - 600

PAA

TTA

MD4151

2000 - 6000

200 - 600

PAA

TTA

MD4152

300 - 1200

25 - 100

PAA

TTA

MD4153

600 - 2400

100 - 400

MD4154

2400 - 3600

70 - 100

200 - 300 PAA

TTA

SiO2 PBTC

Compatibility All MD products are compatible with Alcohol and Glycol Not compatible with NaCl or CaCl2 Brines If Al present keep pH < 8

Closed System Inhibitors Organic based CorrShield OR Series

CorrShield OR Series mg/l

HPA as PO4

OR4400

2000 - 4000

17 - 34

HPS I

TTA

Triazine

OR4411

2000 - 4000

17 - 34

HPS I

TTA

Triazine

DE9886

2000 - 4000

17 - 34

HPS I

Triazine

pH 8 - 10 Control on Organic PO4

Compatibility Above products are compatible with Alcohol and Glycol Not compatible with NaCl or CaCl2 Brines Specifically Designed for CaCl2 Brine HPA as PO4

OR4401 12000 - 18000 240 - 360 HPS I Low conductivity programme

OR4410

If Al present keep pH < 8

50 - 100

DEHA 5 - 10

BZT

Cyclo

Chap 5 MICROBIOLOGICAL CONTROL

Microbiological Control

Microbial Fouling

Microbiological Corrosion Certain forms of MB can attack metal directly and/or indirectly Sulphate reducing bacteria Sulphur bacteria Iron and manganese bacteria Biofilm formers / bacteria, fungi, algae

Microbiological Control Oxidising Biocides > Indiscriminate oxidation Non-Oxidising Biocides > Specific Reactions

OXIDISING Vs NON-OXIDISING BIOCIDES OXIDISING non-specific react also with suspended solids and organic matter halogenated by-products may be formed

NON-OXIDISING specific mode of action organisms may acclimatise to the biocide more expensive

Oxidising Biocides Chlorine gas Sodium hypochlorite Calcium hypochlorite Chlorine dioxide Solid halogen donors Activated Bromide Hydrogen Peroxide Peracetic Acid Ozone

Co m

Fr e

e

re sid

ua lC

hlo rin e

Destruction of chloramines

bin ed Formation of chloramines Ch lor ine

Oxidation of organic compounds

total residual Cl2 (ppm)

BREAK POINT

Combined residual chlorine

Break point Cl2 added (ppm)

OXIDO-REDUCTION POTENTIAL

potential (E)

pH<4,5

chlorine can form HClO + H+ + e- Î ½ Cl2 + H2O E = E30 – 0,06 pH

4,5 <7,5

pre-eminence of HClO HClO + H+ + 2e- Î Cl- + H2O E = E20 – 0,03 pH

pH>7,5

pre-eminence of ClOClO- + 2H+ + 2e- Î Cl- + H2O E = E10 – 0,06 pH

HClO -

ClO

Cl2 -

Cl

1

2

3

4

5

6

7

8

9

10 11 12 13 14

pH

PRE-EMINENCE OF THE IONISED AND NON IONISED SPECIES % HOX 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

HOBr / BrOHOCl / ClO-

4

5

6

7

7.5

8 pH

8.6

9

10

11

ACTIVE FORM VS. PH pH

% HOCl % HOBr

HOBr / HOCl

6

97

100

7

76

98

7,5

50

94

1,9 / 1

8 8,5

24 9

83 60

3,5 / 1 6,7 / 1

9

3

33

11 / 1

50 % HOCl - 50 % ClO-

pH 7,5

50 % HOBr - 50 % BrO -

pH 8,6

REACTION WITH NITROGEN COMPOUND HOX + NH3 ----- NH2X + H2O HOX + NH2X ----- NHX2 + H2O HOX + NHX2 ----- NX3 + H2O

WITH Cl

WITH Br

NH2Cl

NH2Br

NHCl2

NHBr2

NCl3

NBr3

REACTION WITH NITROGEN COMPOUND Ex : pH 8

Br

Cl

HOBr 90 %

HOCl 19 %

BrO- 10 %

ClO- 81 %

PRODUCTS FORMED

WITH Cl

WITH Br

NH2Cl 100 % NH2Br < 10 % HOCl 0 %

HOBr 82 %

ClO- 0 %

BrO- 8 %

Bromamines are almost as toxic HOBr

BENEFIT FROM BROMINE REDUCTION OF CORROSION BROMINE IS A WEAKER OXIDANT Br2 / 2Br- : 1,065V

Cl2 / 2Cl- : 1,36V

HOBr / BrO:- 1,33V

HOCl / ClO- : 1,49V

BrO- / Br- : 0,7V

ClO- / Cl- : 0,9V

REDUCTION OF ELECTROCHIMICAL CORROSION Iron Copper TOLERANT VIS A VIS METALS IRON 2 Fe (HCO3)2 + X2---> 2 Fe (OH)3 + CaCl2 + 6 CO2 MANGANESE MnSO4 + 4 NaOH + X2---> MnO2 + 2 NaCl + Na2SO4 + H2O

BROMINATED PRODUCTS Formation of bromine (HOBr)

Solide compound (BCDMH) Bromine donnor: . pellets . granules

Oxidation of bromine salt by sodium hypochlorite ClO- + Br-

BrO- + Cl-

Bromine salt (40 %)

SOLIDE BROMINE 1-Bromo-3-Chloro-5,5-Diméthylhydantoïne Br CH3 CH3 O

N C C

C

O

N Cl

N - Cl can be Hydrolysed N - Br can be Hydrolysed C5H6BrCIN202 + H2O

C5H7ClN202 + HOBr

C5H7ClN202 + H2O

C5H8N202 + HOCl

HOCl + BrDans le système

HOBr + Cl-

BROMINATOR INSTALLATION MAKE-UP

BROMINATOR

Recommended installation Alternative installation

Non-Oxidising Biocides Modes of Action

Metabolic Inhibitors Interrupt metabolic cycles Enzyme poisons Alter protein structures Irreversibly bind to active sites Surface Active Agents > Alter permeability of cell membrane > Undesirable compounds enter cell > Nutrients and intracellular materials escape

Non-Oxidising Biocides Metabolic Inhibitors > Bromonitrostyrene (BNS) > Methylene bisthiocyanate (MBT) > Dodecylguanidine hydrochloride (DGH) > Isothiazolin (ISZ) > Bromo-nitropropane-diol (BNPD) > Triazines (TBZ) (photosynthesis blockers) > Dibromo-nitrilo propionamide (DBNPA) Surface Active Agents (membrane disrupters) > Quaternary ammonium salts (Quats) > Dodecylguanidine Hydrochloride (DGH) > Cocodiamine

Multiple Active Formulations “Mixed” Populations in Cooling Systems Competition controls growth When populations are balanced, growth is limited Removal of one group upsets balance Multiple Actives Proprietary biocides Expand the “kill” spectrum “Synergism” Reduce growth of resistant strains Better microbe control at lower dosages

Biocide Enhancement Physical Methods Non-Oxidising Biocide Feed Point Highly mixed areas at front end of tower basin Physically separate feedpoint of biocides and polymeric dispersant (oxidisers and non halogen stable chemicals - phosphonates - azoles) Satellite feed biocide(s) to critical equipment prone to MB fouling Feed to hot return to control slime on fouled decks and fill

Biocide Enhancement Physical Methods Time of Day Algaestats - Peak daylight hours

Biocides (halogens) which are not UV-stable - Feed at night to minimise photo degradation

Feed Duration Shot Feed over a short time period - Develop maximum treatment level

High levels of free halogen will accelerate corrosion

Biocide Enhancement Chemical Methods Biocide - Free Halogen Compatibility Incompatible with free halogen > BNS Little or no effect > MBT, DGH, Quats, DBNPA Synergistic with free halogen > BNPD, isothiazolin

Biocide Enhancement Chemical Methods Bio-Surfactants > Improve penetration of biocide into biofilm > Increase transport of biocide into cell > Interfere with cell attachment mechanisms > Assist in sloughing off biomass accumulations > Reduce oil and grease accumulations

Biocide Enhancement Chemical Methods Feeding Bio-Surfactants > Effective with oxidising and non-oxidising biocides > Compatible with free halogen residuals > Once-through or recirculation systems > Intermittent > - High levels > Continuous > - Low levels

Biocide Enhancement Chemical Methods Bio-Surfactants Biocide Enhancer > Wets biofilm aiding penetration of biocide > Low amount of removal of biofilm without biocide Biodispersant > Aids penetration of biocide > Removes biofilm without biocide

GE Betz Spectrus BD1550 “Environmentally friendly” biodegradable biodispersant for biofilm removal and control in industrial cooling systems

Spectrus BD1550 A true “BIODISPERSANT” > Not just a biocide enhancer or surfactant for wetting biofilm to aid penetration of biocides

Spectrus BD1550 REMOVES a significant proportion of biofilm ON ITS OWN

Spectrus BD1550 Spectrus BD1550 has no biocidal activity on its own > a “non-biocidal biofilm control additive”

Spectrus BD1550 improves the effectiveness of biocides in control of bulk water microorganisms

Spectrus BD1550 with biocides Effectiveness on bulk water populations 100 90

% Decrease from Control

80 70

Non-oxidising 60 Biocide 50 40 30 20 10 0

Non-oxidiser plus BD1550 NaOCl plus BD1550 NaOCl

Spectrus BD1550 Removes biofilm from cooling system surfaces > Can be used on it’s own to remove biofilm > Has no biocidal activity on its own > Enhances effectiveness of oxidising and nonoxidising biocides for biofilm removal Readily and ultimately biodegradable Compatible with GE Betz cooling water treatment programmes Mixture of non-ionic and anionic components Patented

Spectrus BD1550 Ideal (on its own or in conjunction with biocides) for cleaning system experiencing biofilms or biofouling > After system upsets such as process leaks > After loss of biocide dosing or biocide effectiveness > During cleaning and sterilisation procedures for minimising risk of Legionella Improves effectiveness of biocides > May lead to lower biocide usage and discharge – Lower concentrations of biocide may be applicable – May replace some biocide additions during the year

Spectrus BD1550 Biodegradable > Readily and ultimately biodegradable – Zahn-Wellens Test – 71% degradation in 7 days – 96%degradation in 14 days Does not Bioaccumulate > Log Kow ranges from < 0 to 2.4 – Range is due to multiple components and surfactant properties – Log Kow is < 3 and the degradation indicates no potential for bioaccumulation

Spectrus BD1550 Typically shot dosed (based on system volume) on its own or in conjunction with intermittent or continuous biocide dosing for biofilm removal > 20 to 50 mg/l BD1550 shot dosed – if system is significantly fouled higher doses up to 100 mg/l may be required > Frequency of addition depends on several factors – degree of biofouling – nutrient concentration / ingress – system half-life – supplemental biocide programme

Legionella LPTALK.PPS Legionella.pdf Legionella Best Practices.pdf Legionella Sampling and testing.pdf Legionella Routine Desinfection.pdf

Chap 6 TREATMENT PROGRAMME DESIGN

Guidelines Cooling system guide.pdf CWT application guidelines.pdf CWT Product Guide 2004 .pdf

Group exercise #5 (30 mn) Using the Cycle up simulation from Group exercise 4 and the application guidelines, design a treatment programme for scale and corrosion control. 1) Define the optimum operating conditions 2) Propose two treatment options if appropriate, one at free pH and the other one with pH control 3) The cost of water is $ 0.7 /m3 and 62° Baumé sulfuric acid costs $ 0.2/kg.The price for all the treatment products is $ 7/kg. Which is the best economical option?

Agenda Day 3 –24 May 2005 09:00 to 10:30 Monitoring and control 10:30 to 11:00 Coffee break 11:30 to 12:30 Troubleshooting 12:30 to 13:00 Final Quizz 13:00 Lunch

Chap 7 MONITORING AND TROUBLESHOOTING

An effective treatment programme should : Inhibit corrosion Minimise deposition and fouling Be effective under broad operating conditions Be economical Have low impact on the environment

Appropriate Treatment Levels are maintained through :

Cooling System Monitoring and Control

Poor Chemical Control Overfeed Underfeed Highly variable results

Overfeed High chemical costs Poor treatment programme performance Risk of environmental violations and fines

Underfeed High corrosion rates Increased equipment maintenance and replacement (i.e. replacing or cleaning of fouled or corroded heat exchanger tubes or bundles) Reduced equipment performance (i.e. reduction in heat transfer)

Highly variable results Unable to evaluate effectiveness of treatment programme Unable to identify changes which affect performance

Poor Chemical Control can lead to : Inconsistent product quality Reduced throughput Higher energy costs due to waterside fouling High labour costs due to increased maintenance or monitoring Risk of equipment damage or failure

Typical Feed Control Methods Manual Semi-Automatic Automatic

Manual Periodic addition to tower sump Manual addition to day tank Chemical pump(s) manually operated (on / off) Manual control of blowdown

Semi-Automatic Chemical shot-fed by on/off timer control of pump(s)

Automatic Microprocessor based Chemical Monitoring and Control System Key features Continuous monitoring of important parameters Continuous pH monitoring and control Continuous control of blowdown Precise chemical feed Local indication and remote alarm capabilities for out of limit parameters

Control – Regulation of cooling water circuit

Version with controller AccuTrak Multifunction Model 100/300/900

blowdown

conductivity circuit

Make-up flow

AccuTrak Controllers Cooling & Boiler water controllers Unique Biocide & Oxygen scavenger control strategies Control up to 3 analogue inputs 11 different controllers in ONE

AccuTrak Controllers Model 100 Blow down Inhibitor Biocides (2)

Model 300 pH control Blow down Biocides (2)

Model 200 pH control (2)

Model 900 Blow down Biocide Free Chlorine

Model 600 (Boiler) Blow down O2 Scavenger Inhibitor

Control – Regulation of cooling water circuit.

Version with PLC/PC PaceSetter Platinum E N T R E E S

conductivity 1

S O R T I E S

pH

modem

24h/24

blowdown

conductivity 2

Make-up flow

HMI

mounted instruments

Benefit of Improved Control Reduced risks associated with chemical underfeed or overfeed Compliance with environmental regulations Improved quality of plant operation Increased water and energy savings Improved plant productivity

Monitoring Tools

Tower Inspection

• Inspection during operation is critical -Screens - Mist eliminators - Deck - Fill

-Distributors - Buildup on surfaces - Air flow louvers - Basin

Field Testing

Water Analysis Required to monitor and control treatment programme Supply important information Enable identification of low level contaminants

Water Analysis Recirculating tower water Make Up Water(s)

Analysis Performed ON SITE

Parameters monitored (operating data) Testing can include : pH Conductivity Suspended solids Alkalinity Hardness Phosphate Other treatment components depending on programme Microbiological populations

Deposit Analysis Samples taken from : Critical heat exchangers Cooling tower Areas of low water velocity and/or high heat flux

Frequency Test Frequency will vary depending on : Cooling System Plant process Plant personnel available

Reporting Never leave the site before you have prepared your analytical report including: > > > >

Analyses performed on site Results from specific investigations Conclusions about the treatment performance Changes possibly needed

Present and discuss you report, and agree on actions with the responsible manager and the the operators Set the date for the next service visit

Compilation/Data Analysis Manual Weekly log sheets Results can be graphed for data trending

Weekly Log Sheets Day O-PO4 (ppm)

1 6

2 8

3 10

4 12

5 14

6 16

7 12

Day O-PO4 (ppm)

8 10

9 10

10 8

11 10

12 12

13 18

14 14

Day O-PO4 (ppm)

15 12

16 13

17 15

18 19

19 13

20 10

21 9

Day O-PO4 (ppm)

22 11

23 10

24 13

25 16

26 15

27 13

28 10

Data Analysis

Reading (ppm) Frequency (number)

6-7

8-9

1

3

10-11 12-13 14-15 16-17 18-19 8

8

4

2

2

Graphing Results 9

Days

8 7 6 5 4 3 2 1 0 6-7

8-9

10-11 12-13 14-15 Orthophosphate, ppm

16-17

18-19

Compilation/Data Analysis Data Acquisition/Management Replaces daily log sheet with a database Permits easy retrieval of historical data Improves operator control - out of limit results are highlighted Incorporates statistical process control Provides graphing capabilities Generates reports

Data management

InfoCalc

Data Manipulation

InfoCalc

Multiple Display

InSight™ Overview Monitoring, diagnostics & control system Developed based on customer needs

Delivers Improved data management Reduced overall spend in water, energy and labor Improved reliability of customer systems Insures regulatory compliance Reduced maintenance

InSight™ •Digital service for utility and process systems •Remote monitoring and diagnostic programme to protect assets and reduce operating costs – Web based Monitoring Service – Automation Packages – Chemical Treatment Programmes – On site Service Programme •Data collection, storage and analysis dashboard •InSight delivers Reduced Spending on Water, Energy and Labor. •CD Marcom/Insight

Corrosion Monitoring Coupons Corrosion rate meter

Corrosion Coupon Test Specimen : OpenLoop By Installation

CORROSION LOOP

RACK DE MONITORING Integrated systems comprised of all or part of: > Flowmetering (rotameters) > Biobox > Biomonitoring > Corrosion coupons > Corrosion meter probe > Steam test exchanger

MONITORING RACK CORROSION COUPONS

CORROSOMETER

DATA COLLECTION

BIOBOX

1000 l/h

500 l/h

BIOMONITOR

1400 l/h

100 l/h

10 l/h COOLING WATER °C

0 0

°C

120

bar

°C

5 0

0

120

TEST EXCHANGER

0

bar

STEAM

10

120

MONITORING RACK

Deposition Monitoring Coupons Monitall Test heat exchanger Model Condenser

MONITALL Fouling electric control Heating probe equiped with thermocouple (skin probe temperature – bulk water temperature) – adjustable heat flux Water circulates around the probe. Monitor ∆T (skin temperature – bulk temperature) Visual aspect of the probe (inox) – deposit analysis Skin Temp. Temperature

Bulk Temp. Plot temperature/ ∆T graphs

Time

Water flowrate: 50 to 150 l/h Power 220V single phase 3A Non ATEX

MonitAll.pdf

Microbiological Monitoring Micro-Organism counts > ATP > Dipslides > PetriFilm > Plate Counts Biobox Biofilm fouling monitor Delta-P monitor Stainless Steel coupons > Ni-Cr mesh coupon

Total ATP

Free ATP

ATP Adenosinetriphosphate

NH2 N

O O-

O

P O

O -

O

P O

N

O -

O

P O

C H2

N

N

O

-

OH

OH

• Energy source for biochemical reactions • Produced in ALL living cells • Decreases if cell dies

ATP DETECTION microorganism

+

ATP is released into buffered solution

lysing agent

Light + ATP

Luciferin

Luciferase

Overall System Monitoring U-Coefficients Computer analysis - Trends - Predictive programmes

Field Analytical Equipment Global and Advanced WAL test kits > GE Betz DR/2400 – GE Betz DR/890 > pH, Conductivity meter > Digital titrator (Titrimetric analysis) Portable Field Microscope Microbiological Monitoring > Cultivation methods : dipslides, petrifilm > ATP method : Bioscan II

Laboratory - Analytical Services 1. Standard Analysis - Monitoring ¾ ¾ ¾ ¾ ¾ ¾

Fluids (water & oil) Deposits Coupons Microbiological Cultural Examinations Resins Metallurgy

2. Problem Solving

Laboratory - Analytical Services ¾

Inorganic & Organic Analysis

¾

Microbiological Analysis

¾

Metallurgy

> > > >

Characterization & Quantification ppb, ppm to % levels Bulk & localized surface analyses No certification of customer end product or conformance towards local regulations

Analytical Instrumentation

Inorganic Analysis > Inductive Coupled Plasma Emission Spectroscopy (Radial and Axial) > Flame - Atomic Absorption Spectroscopy > Ion Chromatography > Segmented Flow-UV Analysis > Automated Titrimetric Analysis > Wavelength Dispersive X-ray Fluorescence Analysis > ECS 3000 – Coulometric Analysis

Organic Analysis > Thermo Gravimetric Analyzer > FT Infra-Red Spectroscopy > CHNS-Analyzer > Mass Spectrometry > Gas & Liquid Chromatography > Total Organic Carbon Analyzer > Total Kjeldahl Nitrogen Analyzer

Microbiology Testing > Cultivation methods – counts. > Product evaluations. > Toxicity testing (Microtox, Respiration studies) > Microscopic examinations. > Evaluation of rapid microbiological monitoring tools for use on site. > Activated Sludge characterization. > Macro-fouling characterization.

Metallurgy 1. Surface Analysis – Scanning Electron Microscope 2. Failure Analysis – Investigations & Recommendations 3. Corrosion Coupons

– Corrosion Rate, Pit depth

Metallurgical Analysis Failure Analysis & Problem Solving Expertise - Cooling - Boiler - Metals Process - Hydrocarbon Process Water Separation Equipment Boiler -Tube long term Overheating Damage

Membrane Autopsy - Spiral Wound - Hollow Fiber

LT Overheating Good

Laboratory - Application 1. Cooling ¾ ¾

Tower Rig : ELT (NCC), BTU Steriliser Treatment, Scale Inhibition, Cleaning

2. Sentinel (central heating) ¾ ¾

Domestic Heating Rig BSI-Rig (Metallic/Non-Metallic)

3. Water/Waste water ¾ ¾

Clarification, Emulsion breaking, Flotation Metals Removal, Sludge dewatering, Antifoam

Laboratory - Application 4. Hydrocarbon ¾ Anti-fouling, Oxidation Stability ¾ Desalting, High Temperature corrosion ¾ Oil Characterization 5. General Process ¾ Paint Spray Booth simulation ¾ Dust Control, Deposit Inhibition ¾ Foam Control, Cleaning

New Services 2004 Metal Processing Simulation Line Corrosion Performance • Neutral Salt Spray

ivation Rinse

Drying

Spray Pretreatment

Drying

Liquid Paint Coating

Mechanical Performance • Impact

Drying

• Pencil hardness • Bending

The Future: Lab On A Disk Quickly, accurately, simply tests eight key analytes in water: 1. 2. 3. 4. 5. 6. 7. 8.

Calcium Molybdate pH t-Alkalinity o-Phosphate Sulfite Magnesium Chlorine

What systems can I test? Targeted at….. • Steam Boilers • Cooling Towers Also works on……. • Closed-loop cooling • Mid-pressure Boilers

How does it work? 1.

Inject 5 ml filtered water in sample device

2.

Allow 2-minute reaction time

3.

Close sampling device to dry disk and allow 6 minutes development time

4.

2-minute read and report cycle – all automatic

10 Minutes Total

Disks

DVD Reader Results! (Developing USB driver for PocketPC)

Group exercise #6 (30 mn) Trouble shooting Exercise.pdf

Training Quizz (30 mn) Read the questions carefully. Do not extrapolate. T - F (True – False): Select the right statement A-B-C: one or more answer(s) is(are) correct Results of calculation as appropriate