Various metals are used in industrial cooling systems, each with specific properties and benefits. Selecting and applying the right chemical treatment agents is critical to prevent corrosion, minimize deposits and maximize system efficiency. This article highlights the most common metals used in cooling systems, their properties and the chemical measures that need to be taken to protect them.

Table of contents

Importance of metals in cooling systems

Metals play a central role in cooling systems due to their thermal conductivity, mechanical stability and durability. The correct selection and treatment of metals are crucial to prevent corrosion and ensure the efficiency of the cooling system.

Typical metals in cooling systems

Steel

Steel is widely used in industrial cooling systems, especially in piping and tanks. Steel offers good mechanical strength, but is susceptible to corrosion, especially in the presence of oxygen and chlorides.

Copper

Copper is often used in heat exchangers as it offers excellent thermal conductivity. However, copper is susceptible to corrosion in acidic and alkaline environments and in contact with ammonia and sulphur compounds.

Aluminum

Aluminum is used in cooling towers and evaporators because it is lightweight and corrosion-resistant. However, it is sensitive to alkaline solutions and chloride-containing environments.

Stainless steel

Stainless steel is used in cooling systems where high corrosion resistance is required. It offers excellent resistance to a wide range of chemical attacks, but is more expensive than other materials.

Chemical treatment and protective measures

Corrosion inhibitors

Corrosion inhibitors are essential for protecting metal surfaces in cooling systems. They form a protective layer that protects the metal from oxidative attacks. Typical corrosion inhibitors include phosphates, silicates and organic compounds. It is important to note that certain inhibitors may be unsuitable for specific metals.

Photo: Here you will find a rough overview of our equipment for cooling systems as well as a guide to subdividing the product groups according to application and task.

Hardness stabilizers

Hardness stabilizers prevent the precipitation of calcium carbonate and other mineral deposits. This is particularly important in systems with high temperatures and water hardness in order to maintain the efficiency of heat transfer.

Dispersing agent

Dispersants keep suspended solids in suspension and prevent them from settling. They are important to prevent the accumulation of dirt, corrosion products and biological material.

Biocides

Biocides are used to control the growth of microorganisms such as bacteria, algae and fungi. They prevent biological fouling and protect the system from biological attacks.

Exemplary treatment of some metals and chemical compounds

Steel and its treatment

Steel is susceptible to general and pitting corrosion. The use of corrosion inhibitors such as nitrites and phosphates can effectively protect steel. Dispersants help to prevent the deposition of corrosion products, while biocides control biological growth. However, phosphates should be avoided in systems with a high oxygen content as they can lead to deposits.

Copper and its treatment

Copper can be corroded by oxygen, sulphur compounds and ammonia. Benzotriazole and tolytriazole are effective corrosion inhibitors for copper, which form a protective layer on the copper surface. Hardness stabilizers and biocides supplement the protection. However, biocides containing chlorine should be avoided as they can accelerate the corrosion of copper.

Aluminum and its treatment

Aluminum is corrosion resistant, but sensitive to alkaline environments and chlorides. Silicate inhibitors provide protection by forming a protective layer on the aluminum surface. It is important to control the pH of the water and use dispersants to prevent scaling. Phosphates and strong alkaline hardness stabilizers should be avoided to prevent corrosion.

Stainless steel and its treatment

Stainless steel is resistant to many chemical attacks, but is susceptible to stress corrosion cracking in chloride-containing environments. Inhibitors containing molybdenum can provide additional protection. Regular application of biocides prevents biological fouling, while hardness stabilizers and dispersants control deposits and dirt. Chlorides should be minimized to avoid stress corrosion cracking.

Summary and recommendations

The selection of the right metal and the appropriate chemical treatment is crucial for the efficient and long-lasting operation of cooling systems. Corrosion inhibitors, hardness stabilizers, dispersants and biocides play a central role in the maintenance and protection of these systems. Targeted chemical treatment can effectively prevent corrosion, deposits and biological contamination.

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