What is the main component of dirt?

Sediments in circulating water: 1. The precipitation of salts in water – The solubility product effect: As the concentration of circulating water increases, various ions in the circulating cooling water system, such as sodium ions, potassium ions, carbonates, phosphates, silicates, and their calcium, magnesium, and iron compounds, gradually become saturated and form crystals, leading to precipitation; this deposition occurs especially on the walls of cooling towers and near water baffles. 2. Sludge formed by bacteria and algae in the water – Various suspended particles, sand, silt, clay, microorganisms, oil, etc., can all be introduced into the system through make-up water. Since open-loop cooling water systems are exposed to the air, especially during the summer when temperatures are high and there is plenty of sunlight, a large number of microbial organisms such as bacteria and algae reproduce rapidly. They often gather in areas where the water flow is slow or where there are sudden changes in flow velocity, such as on the baffles of cooling towers and in cold water tanks, thereby entering the collection tanks, water tanks, and the shell sides of heat exchangers. It has an impact on settlement and scaling. Oil stains often adhere to metal surfaces, acting as a type of dirt adhesive. The oil film affects heat transfer, serves as a nutrient source for microorganisms, prevents inhibitors from reaching the metal surface, and impairs the corrosion inhibition effect. 3 Sludge generated in the air: The air contains many suspended particles, and sand, silt, clay, sludge, bacteria, and other substances carried by the air contribute to overall scaling in the system. Impurities in the air cause deposits to form within the system. Oxygen and carbon dioxide accelerate corrosion ； Gases such as sulfur dioxide and hydrogen sulfide cause the anode inhibitors to be reduced into insoluble deposits; hydrogen sulfide is highly corrosive and forms iron sulfide deposits, which further exacerbate corrosion ； Ammonia selectively corrodes copper and copper alloys. 4. System-related deposits: Corrosion of the components within the system can also lead to the formation of deposits, which spread over a large area and quickly block water supply pipes and heat exchangers. Sediments will further accelerate corrosion and scaling

Related discussion: How is the fouling coefficient of circulating water calculated? http://bbs.hcbbs.com/thread-162434-1-1.html (Source: Haichuan Chemical Industry Forum)

Dirt is mainly composed of organic matter in water, microbial colonies and secretions, sediment, dust, etc. The scale has a soft texture, which not only reduces heat transfer efficiency but also causes corrosion beneath the scale, shortening the service life of the equipment.