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What is the main method of reducing deposition of solids in cooling water systems?
What is the main method of reducing deposition of solids in cooling water systems?
- Adding polymeric organics
- Maintaining high pH levels
- Adding sulfuric acid
- Using sequestering agents and chelates (correct)
Why is it important to keep the cycles of concentration low in cooling water systems?
Why is it important to keep the cycles of concentration low in cooling water systems?
- To promote the deposition of solids
- To reduce the need for specialty chemicals
- To minimize deposits (correct)
- To increase the efficiency of the system
What effect does maintaining a lower pH (6.5 to 7) have on solids in suspension?
What effect does maintaining a lower pH (6.5 to 7) have on solids in suspension?
- It helps keep solids in suspension (correct)
- It promotes the deposition of solids
- It accelerates corrosion of steel and copper
- It increases the need for specialty chemicals
What is added to cooling water systems to keep scale-forming salts in solution at high concentration levels?
What is added to cooling water systems to keep scale-forming salts in solution at high concentration levels?
Why do plants that use source water with high hardness add sulfuric acid?
Why do plants that use source water with high hardness add sulfuric acid?
What is the drawback of some of the compounds used to keep scale-forming salts in solution at high concentration levels?
What is the drawback of some of the compounds used to keep scale-forming salts in solution at high concentration levels?
What is the purpose of adding chlorine to control biological growth in cooling towers?
What is the purpose of adding chlorine to control biological growth in cooling towers?
What is the purpose of using crystal modification chemicals in cooling water systems?
What is the purpose of using crystal modification chemicals in cooling water systems?
How does make-up proportional blowdown control the cycles of concentration in a cooling tower?
How does make-up proportional blowdown control the cycles of concentration in a cooling tower?
What is the purpose of applying protective coatings, such as paint or metal plating, in cooling water systems?
What is the purpose of applying protective coatings, such as paint or metal plating, in cooling water systems?
What is the purpose of using sacrificial anodes or induced electric currents in corrosion control?
What is the purpose of using sacrificial anodes or induced electric currents in corrosion control?
What is the purpose of chemical inhibitors in cooling water systems?
What is the purpose of chemical inhibitors in cooling water systems?
What is the reason for no longer using chromate in systems from which water can escape?
What is the reason for no longer using chromate in systems from which water can escape?
Which alternative to chromate is mentioned as nontoxic?
Which alternative to chromate is mentioned as nontoxic?
How long does it take for polysilicates and molybdates inhibitors to form a protective film?
How long does it take for polysilicates and molybdates inhibitors to form a protective film?
What is the purpose of installing a Y-strainer or equivalent upstream of the blowdown valve?
What is the purpose of installing a Y-strainer or equivalent upstream of the blowdown valve?
How do oxidizing chemicals like chlorine operate in protecting against biological fouling?
How do oxidizing chemicals like chlorine operate in protecting against biological fouling?
Which statement about the use of biocides is accurate?
Which statement about the use of biocides is accurate?
What is the purpose of shock feeding biocides into the cooling system?
What is the purpose of shock feeding biocides into the cooling system?
What is an effective method mentioned to control wood deterioration?
What is an effective method mentioned to control wood deterioration?
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Study Notes
Cooling Water Systems
- The main method of reducing deposition of solids in cooling water systems is to keep the cycles of concentration low.
Scale Formation and Prevention
- Maintaining a lower pH (6.5 to 7) helps keep solids in suspension.
- Polymers or phosphonates are added to cooling water systems to keep scale-forming salts in solution at high concentration levels.
- Plants that use source water with high hardness add sulfuric acid to remove carbonate alkalinity and reduce pH.
- The drawback of some compounds used to keep scale-forming salts in solution is that they can break down and lose efficacy over time.
Biological Growth Control
- Chlorine is added to control biological growth in cooling towers by oxidizing and breaking down microorganisms.
- The purpose of using crystal modification chemicals is to prevent scale formation by modifying the crystal structure of minerals.
Corrosion Control
- Applying protective coatings, such as paint or metal plating, prevents corrosion by creating a barrier between the metal and corrosive substances.
- Sacrificial anodes or induced electric currents are used in corrosion control to drive the corrosion reaction away from critical system components.
- Chemical inhibitors are used to prevent corrosion by forming a protective film on metal surfaces.
Inhibitor Characteristics
- Chromate was previously used as an inhibitor but is no longer used due to toxicity concerns.
- Phosphates and molybdates are alternative, nontoxic inhibitors that form a protective film in 30-90 days.
- Polysilicates and molybdates inhibitors take 30-90 days to form a protective film.
System Maintenance
- Installing a Y-strainer or equivalent upstream of the blowdown valve prevents debris from entering the blowdown line.
- Oxidizing chemicals like chlorine operate by oxidizing and breaking down microorganisms, preventing biological fouling.
- Biocides can be shock fed into the cooling system to control biological growth.
- An effective method to control wood deterioration is to treat cooling water systems with biocides.
Biocide Use
- Biocides should be used in a controlled manner to target specific microorganisms and prevent resistance development.
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