Water Cooling Systems

Just as living organisms cannot survive without water, oil refineries and petrochemical plants cannot operate without water. Water in water cooling systems is used to provide steam and fire extinguishing systems. Petroleum products and fuels produced after distillation and various catalytic and cracking processes must be cooled. Water is the best fluid for this.

Corrosion through water

Different water sources cause numerous corrosion problems that require careful attention and investigation. Despite the more limited characteristics of water (10-40 ° C and 4-5 bar) compared to those of crude oil and petroleum products, all known corrosion phenomena occur with equipment in contact with water. On the one hand, the theory of corrosion of metals in water is well known and a wide range of anti-corrosion measures exist and can be used. On the other hand, there are many factors, mainly the diverse physical and chemical composition of water and their changes, that affect the corrosion of metals in water, making it difficult to predict corrosion.

Water in fire-fighting pipes

Sometimes fire-fighting pipelines are filled with drinking water disinfected by biocides. The water in such pipelines is not circulated and remains stagnant for a long time. Despite the initial chlorination of drinking water, a strong MIC (Minimum Inhibitory Concentration) (mainly caused by iron bacteria) can cause holes in the pipe wall with a thickness of 6 mm after 2-3 years. Such cases are far from safety principles, since the lack of water pressure in the fire-fighting pipeline during a fire in an oil refinery can lead to disaster.

The main problems of systems with circulating water

The corrosion rate of carbon steel decreases over time in most water installations due to the formation of corrosion products on the surface (similar to atmospheric corrosion). The main problems in water systems are corrosion, scaling, and biofouling, the cause of which is most often related to MIC.

Refining and Petrochemical Water Systems Against Corrosion

Almost all cooling water systems are protected with chemicals that include corrosion inhibitors, biocides, and antifouling agents. Protective coatings and anodic protection are also used to control corrosion of the internal surfaces of heat exchangers that come into contact with the cooling water. Their effectiveness is checked every 4-5 years with a system overhaul. Sometimes designers do not consider all technical parameters when choosing coatings. For example, the cooling water temperature usually varies from 30 to 35 ° C. However, steam at a temperature of 200 ° C is introduced into many heat exchangers for several hours to wash the internal surface of hydrocarbons from them. Most water-resistant coatings are not resistant to high temperatures, as a result of which they are destroyed and must be repaired.

Anodic protection installed inside heat exchangers cannot always be effectively used due to the lack of consideration for the electrical current of the water. Corrosion monitoring should be used in all water systems.

Protection with anti-scale and anti-corrosion Mitreh

Today, in industries with water circulation systems, the problem of scale and corrosion in expensive systems and equipment cannot be ignored. Because ignoring these problems imposes huge losses and costs on industries in the world and also in Iran. Usually, companies can perform periodic scale removal at a much lower cost and increase the life of devices and equipment productivity, as well as control (reduce or eliminate corrosion) corrosion in their equipment and facilities. Abrizan Industrial Research Company, in the course of its research, has studied a solution to reduce corrosion losses in industries and by inventing a solution that, in addition to scale removal, also has anti-corrosion capabilities (anti-scale and anti-corrosion Mitreh), was able to take a big step towards reducing the costs caused by corrosion in large industries.