1. Industrial cooling water A Studyby
Manan Upadhyay
Shani Pandya
Proff. Himanshu Choksi
School of Technology (PDPU)
Dr.S.K.Shukla
Hydro-Chem. (Technical director)

2. Industrial Cooling Water- A Study
Abstract
Water is used as a coolant in various recirculation cooling systems due to its availability, low cost and effective heat transfer properties. But at prevailing temperature in cooling system the main problem associated with cooling water are corrosion, scaling, fouling and microbiological growth ,which, if left untreated can lead to reduce operating efficiency, increased maintenance cost, loss in heat transfer efficiency and energy and ultimate shutdown. In this paper we are first going to discuss why water is so important in industry, which type of problem we face in industrial cooling water system, then we are going to discuss evaluation and control of that problems & how vital role water chemistry play for prediction of corrosion and scale. Also we are going to discuss product evaluation of CORONIL – 202 and how it is helpful to resolve associated problem.
22/12/2012
Industrial Cooling Water- A Study

3. The choice for water as coolants is because of…..
Readily available in plenty
Inexpensive
Easily handled
Carry large amount of heat per unit volume
Does not expand or compress significantly within normally encountered
temperature ranges
Does not decompose
22/12/2012
Industrial Cooling Water- A Study

4. Problems encountered, if Recirculating Water is not treated…..
Corrosion of metals in contact with cooling water
Deposition on cooling surfaces
Microbiological growth in the cooling tower and deterioration of cooling tower timber.
Fouling of heat transfer surface
Pollution of environment
22/12/2012
Industrial Cooling Water- A Study

5. Untreated Recirculating Water can cause ..
Reduced operating efficiency
Increased maintenance cost
Loss in heat transfer efficiency and energy
Choking of water passage, increase pressure drop
Hot-spot causing equipment failure
Reduced output
Increased pumping cost
Necessity of frequent cleaning
Frequent shutdown, loss in manpower and production
22/12/2012
Industrial Cooling Water- A Study

6. Problems associated with Cooling Water 1.corrosion
Types of corrosion.
Pitting or localized attack
Uniform
Stress corrosion cracking
Tuberculation
Factors affecting corrosion
Chemical Factors pH
Dissolved solids
Dissolved gases
Suspended solids
Microbial growth
Physical Factors
Relative areas
Temperature
Velocity
Heat transfer
Metallurgical impacts
22/12/2012
Industrial Cooling Water- A Study

7. Industrial Cooling Water- A Study
Continue..
2. Scaling
Scaling can cause the following problems :
Reduced or uneven heat transfer
Hot – spot, causing equipment failure
Poor corrosion inhibition
Reduced output
Increased pumping cost
Necessity of frequent cleaning
Some of the common scales are :
Calcium Carbonate
Calcium Sulphate
Silicates
Calcium Orthophosphate
Magnesium Salts
Iron Salts
Factors that influence scaling :
Temperature
pH or Alkalinity
Solubility
22/12/2012
Industrial Cooling Water- A Study

8. Industrial Cooling Water- A Study
Continue..
3. Fouling
Fouling is the deposition of suspended matter other than scales. These are water insoluble and can be water borne or air borne.
Some of the common foulants are:
Dirt and Silt
Sand
Corrosion products
Natural organics
Microbial matter
Extent of fouling depends on:
Water characteristics
Temperature
Velocity
Microbial growth
Corrosion product
Oil
22/12/2012
Industrial Cooling Water- A Study

9. Industrial Cooling Water- A Study
Continue..
4. Microbiological growth
Excessive growth of microscopic organism which can cause
following problems :
Reduce heat transfer or restrict circulation in heat exchangers.
Plug tubes in heat exchangers, causing emergency shutdown and loss of production.
Deteriorate metal via under deposit corrosion.
Destroy cooling tower timber.
22/12/2012
Industrial Cooling Water- A Study

10. Industrial Cooling Water- A Study
Continue..
Basic Microorganism
Algae
Green algae (Chlorophyta)
Blue green algae (Cyanophyta)
Fungi
Filamentous mold
Yeast like growth
Bacteria
Aerobic capsulated
Aerobic spore forming
Temperature
Phosphorous compound
Dirt
Process leaks such as Ammonia, Alcohols, Ethanolamine, Urea, Petroleum etc.
Oil and fatty contaminants
Factors affecting Microbiological growth
22/12/2012
Industrial Cooling Water- A Study

11. Scale and corrosion indices
Langelier’s Saturation Index (LSI)
Ryznar’s Stability Index (RSI)
Puckorius Practical Scale Index (PSI)
All these three indices are based on pH of saturation (pHs). The value of pHs can be calculated from the from the following formula.
pHs = (9.3 + A + B) – (C+ D)
A = Total dissolved solids (mg /I)
B = Temperature of bulk water (0C.)
C = Calcium hardness as CaCO3 (mg / I)
D = Total alkalinity as CaCO3 (mg / I)
22/12/2012
Industrial Cooling Water- A Study

12. Scaling severity of keyed indices
LSI* PSI* / RSI* Condition
________________________________________________________
Extremely Severe
Very Severe
Severe
Moderate
Slight
Stable Water**
No scaling, very slight
tendency to dissolve scale
No scaling, slight tendency
to dissolve scale
No scaling, moderate
No scaling, strong tendency
No scaling, very strong
LSI = Langelier Saturation Index
RSI = Ryznar Stability Index
PSI = Puckorious Practical Scale Index
No scaling, no tendency to dissolve scale
22/12/2012
Industrial Cooling Water- A Study

13. Role of Water Chemistry in prediction of Corrosion and Scale
Langelier and Ryznar indices give satisfactory results
but there are some disputes.
Water with positive L.I. can be corrosive and negative
L.I. can be noncorrosive.
To make system free from corrosion ratio of hardness and
chloride of 2, and alkalinity and chloride + Sulphate ratio of 5 is desirable.
L.I. require modification by incorporating chloride, sulphate, dissolved oxygen and exposure hr. etc.
22/12/2012
Industrial Cooling Water- A Study

14. Evaluation of Problems
1.Corrosion
Non heat transfer loop
(weight loss by coupons)
Electrical resistance method
Test heat exchanger
22/12/2012
Industrial Cooling Water- A Study

15. Industrial Cooling Water- A Study
2.Scaling
Perforated coupons
Visual observations of heat exchangers
Test heat exchanger
Scalometer
22/12/2012
Industrial Cooling Water- A Study

16. Evaluation of Problems
3. Microbiological growth
Visual observation
Total bacteria count
Biofouling test unit
Evaluation of Problems
22/12/2012
Industrial Cooling Water- A Study

17. Corrosion Control The general concepts for corrosion control are:
a. Blow down
b. Chemical treatment
Estimated performance of Various blends
No. Treatment %Corrosion inhibition
1. Chromate-Zinc-Polyphosphate
2. Chromate-Zinc-Polyacrylate
3. Chromate-Zinc-Polyacrylate
4. Azole-Zinc-Polyphosphate
5. Azole-Zinc-Diphosphonate
6. Azole-Zinc-Phosphonate-Polycrylate
7. Polyphosphate-Phosphonate-Polyacrylate
8. Polyphosphate-Phoaphonate-Polyacrylate
9. Ferrocyanide-Zinc-Polyphosphate
10. Lignin-Zinc-Polyphosphate
22/12/2012
Industrial Cooling Water- A Study

18. Scaling and Fouling control
Controlling the cycle of concentration thereby limiting the concentration of the scale forming salts.
Removing or reducing the minerals before they enter the system by using softer.
Acid feeding
Mechanical means like increasing the water velocity and designing exchangers with large surface areas.
Most important of all is to treat with chemicals to prevent
scale (practical and cost effective)
Chemical treatment
Organophosphonate + Low molecular weight anionic polymer
Properties
Hydrolytic stability
Sequestration
Threshold inhibition
Crystal distortion
Dispersion
22/12/2012
Industrial Cooling Water- A Study

19. Industrial Cooling Water- A Study
Antiscalents
Aminotris (Methylene Phosphonic Acid)
1,Hydroxyethylidene 1, 1, Diphosponic Acid
Ethylenediamine Tetra (Methylene Phosphonic Acid)
Hexa Methylence Diaminetetra
(Methylene Phosphonic Acid)
Diethylenetriamine Penta (Methylene Phosphonic Acid)
2 – Phosphono Butane – 1,2,4 Tricarboxylic Acid
Polymino Polyether Methylene Phosphonic Acid
Phosphino Carboxylic Acid
Dispersants
Polyacrylic acid
Polymaleic acid
Polyacrylamide
Acrylic acid : Sulphonic acid :
Sulphonated styrene ter-polymer
Polyaspartate
22/12/2012
Industrial Cooling Water- A Study

20. Microbiological growth control using suitable Biocides.
Common Biocides
Chlorine
Chlorine Dioxide
Para Toluene Sodium Sulfonchloramide
1,3 – Dichloro – 5,5-DimethyI Hydantoin
N-Chloro Succinimide
Cyanuric Trichloride
Methylene Bisthiocyanate
Chloroethylene Bisthiocyanate
Acrolein
Copper Citrate
Copper Chelate of Glycine
Bis (tri-n-butyltin) Oxide
Dodecyl Guanidine Hydrochloride
Tri and Pentachloro Phenols
Sodium Penta Chloro Phenate
N-dodecyl Benzy – N,N,N-triethyl Ammonium Chloride.
Zinc Dimethyl Dithiocarbamate
2,2 – Dibromo-3-Cyanoacetamide
2,3 – Dichloro naphthoquinone
Isothiazolinone
22/12/2012
Industrial Cooling Water- A Study

21. Industrial Cooling Water- A Study
Product Evaluation
Product : CORONIL – 202
Corrosion Data
Metal Used : Mild Steel
Density : 7.8 g/cc
Area of specimen : 5.00in2
Exposure hours : 72
Stirring : 600 RPM
Temperature : C + 10C
22/12/2012
Industrial Cooling Water- A Study

22. Industrial Cooling Water- A Study
Results
Process Soft Synthetic
Water water cooling
water
Blank
Weight loss (mg)
Corrosion rate (mpy)
Formulation ( CORONIL – 202 )
Weight loss (mg)
Corrosion rate (mpy)
% corrosion Inhibition
22/12/2012
Industrial Cooling Water- A Study

23. Product Evaluation (Contd.) Product : CORONIL – 202
Water analysis
Process Soft Synthetic cooling Water water water pH
Conductivity (micro mho)
TDS, ppm
Ca-hardness, ppm
Mg-Hardness, ppm Nil
Total hardness, ppm
P.Alkalinity, ppm Nil Nil
M.Alkalinity, ppm
T.Alkalinity,ppm
Chloride as CI
Sulphate as so
Calcium carbonate Inhibition
Conditions
Calcium carbonate : 400PPM
Time : 20 Hours
Temperature : C
pH :
% Inhibition : (Minimum)
22/12/2012
Industrial Cooling Water- A Study

24. Product Evaluation (Contd.) Product : CORONIL – 202 (Contd.)
Calcium Sulphate Inhibition
Conditions
Calcium Sulphate : ppm
Temperature : C
Time : Hours
pH :
% Inhibition : (Minimum)
Dispersive Power
Kaolin Clay : ppm
Calcium Carbonate : ppm
Standing time given : hours
% Dispersion : (Minimum)
22/12/2012
Industrial Cooling Water- A Study

25. Industrial Cooling Water- A Study
Advantages of Product CORONIL-202
Calcium Carbonate Crystals grown (static CaCO3 threshold inhibition test conditions) in the absence of CORONIL
Distorted Calcium Carbonate Crystals grown (static CaC03 threshold inhibition test conditions) in the presence of CORONIL
22/12/2012
Industrial Cooling Water- A Study

26. Industrial Cooling Water- A Study
Calcium Sulphate Crystals grown (static CaSO4 threshold test condition) in the absence of CORONIL
Distorted Calcium Sulphate Crystals grown (static CaSO4 threshold test condition) in the presence of CORONIL
22/12/2012
Industrial Cooling Water- A Study