Technically sound chemical and mechanical programs must be combined to achieve maximum productivity. Scale, corrosion, fouling and microbiological deposits all contribute to problems with heat transfer and ultimately, the quality of your process. Finding the right answers to avoid problems in a cooling water system can be a complex task. A good treatment program must address a variety of problems and yet be compatible throughout the entire system. You can rely on Cortec to provide Vapor Corrosion Inhibitors (VCI) to enhance your programs for your particular needs. Weather you need Cortec’s unique VCI (Volatile Corrosion Inhibitor) products or just VCI (Volatile Corrosion Inhibitor) building blocks to enhance your formulations, Cortec has the right product.

Cooling Water Problems and Solutions

Corrosion - Most metals used in cooling water systems are very susceptible to corrosion. Keeping surfaces clean is one of the important aspects of preventing corrosion, since under deposit corrosion can take place and result in serious damage. Corrosion can be uniformly distributed throughout the system or it can be localized, causing severe pitting and rapid equipment failure.

Scale - Minerals such as calcium and magnesium are relatively insoluble in water and can form scale deposits when exposed to conditions commonly found in cooling water systems. A layer of scale as thin as 1/64 inch can reduce heat exchanger efficiency by 15%. Scale inhibitors such as threshold inhibition chemicals and scale conditioners can control scale formation.

Cortec provides its unique Vapor Phase Corrosion Inhibitor technology combined with polyphosphates to combat against Corrosion and Scale in Cooling Water. VCI-646 and VCI 649 are two finished products for open and closed loop systems respectively. Cortec also allows you to formulate your own products according to the specific need of the account by supplying VCI (Volatile Corrosion Inhibitor) building block, S-69 or S-69 Powder. These products can be easily incorporated in your formulations to provide your product with unique VCI ability.

Biocides for Cooling Water Systems

Microbiological growth is one of four major harmful phenomena that can occur in a cooling water system. The formation of bio-deposits on heat transfer surfaces results in significant heat transfer loss. These bio-deposits or slime layers can lead to the promotion of three other major problems: corrosion, scale and fouling. Microbiological growth can be minimized by physical means such as back flushing and air rumbling of heat exchangers and cleaning of filters. However, these physical methods will not destroy or prevent the growth of microorganisms; chemicals called biocides are used for this purpose.

Types of biocides

There are two major types of biocides: oxidizing and non-oxidizing. Oxidizing destroy important cellular components in microorganisms, resulting in death of the organisms. Chlorine gas and liquid sodium hypochlorite chlorine are the most widely used oxidizing products. Another oxidizing biocide that is fed in many applications is bromine, which is available as a solid or liquid. Bromine offers several performance and safety advantages over chlorine and sodium hypochlorite. Non-oxidizing biocides have been typically used to control severe upset conditions or to enhance oxidizing biocide programs. Due to increasing environmental concerns, use of non-oxidizers is becoming more common place. Non-oxidizing biocides are organic compounds that react with specific cell components within a microbe to ultimately destroy that cell.
Cortec’s VCI (Volatile Corrosion Inhibitor) products are compatible with most of the biocides whether it might be oxidizing or non-oxidizing type. It is although recommended to use non-oxidizing biocides along with Cortec’s VCI products. If an oxidizing program is used, it is advised to consult with Cortec representative about appropriate dosage rates requirements. Depending upon the free Chlorine concentration in the system, the dosage might need to be adjusted.

Monitoring your program is as important as using good chemicals. Several monitoring tools available include:

• Easy manual tests for analysis of conductivity pH, alkalinity, hardness, chlorine and treatment levels and many others.

• Corrosion coupons, small metal strips used to establish relative corrosion rates of different metals in cooling systems.

• The Corrater*, an electronic instrument that measures the corrosion and pitting tendencies in a cooling system.

The Corrosion Test Rack that evaluates the effectiveness of corrosion inhibition programs on non-heat transfer surfaces and is designed to be used with either corrosion coupons or Corrater probes.

The Deposit Monitor indicates the presence of corrosion, scale or fouling on heat transfer surfaces.

Microbiological analyses provide answers on the kinds and quantities of bacteria present in a cooling system.

*Registered trademark of Rohrback Corporation