First, scaling deposition:
Cooling water in industrial systems is typically sourced from groundwater or municipal tap water. These water sources contain high levels of dissolved solids, which accumulate as the water circulates and concentrates within the system. As the water is reused, the concentration of these minerals increases, especially when the system operates at high temperatures. This leads to changes in water quality, and when the concentration of certain soluble salts exceeds their solubility limits, scale begins to form. Common scale-forming compounds include calcium carbonate (CaCO₃), calcium phosphate (Ca₃(PO₄)₂), calcium sulfate (CaSO₄), and calcium silicate. These substances have very low solubility, with CaCO₃ only dissolving up to 20 mg/L at 0°C, and Ca₃(PO₄)₂ having a solubility of just 0.1 mg/L. Their solubility decreases further with rising temperature and pH, making them prone to crystallization under supersaturated conditions, particularly on heat transfer surfaces. When water flow is slow or the surface is rough, these crystals tend to deposit, forming hard scale layers that reduce efficiency and increase energy consumption. To control scaling, three main approaches are commonly used: (1) reducing the concentration of scale-forming ions to stay within safe limits, (2) maintaining equilibrium among these ions to prevent precipitation, and (3) inhibiting crystal growth through chemical additives. The choice of method depends on factors such as the volume of circulating water, system requirements, and the availability of treatment chemicals. A well-designed scaling control strategy can significantly improve system performance and extend equipment life.2. Corrosion:
Corrosion in cooling water systems, particularly for carbon steel, is an electrochemical process. Due to the natural heterogeneity of metal surfaces and the varying conditions of the surrounding solution, different areas on the metal surface develop regions of varying potential—some act as anodes (low potential), while others act as cathodes (high potential). This creates small galvanic cells, leading to corrosion through oxidation and reduction reactions. The general reaction sequence is as follows: At the anode: Fe → Fe²⺠+ 2e⻠At the cathode: ½O₂ + H₂O + 2e⻠→ 2OH⻠In the water: Fe²⺠+ 2OH⻠→ Fe(OH)₂↓ Further oxidation: 2Fe(OH)₂ + ½O₂ + H₂O → 2Fe(OH)₃↓ Since surface unevenness is inevitable, electrochemical corrosion is widespread. As long as metal is exposed to oxygen-containing water, this process continues. To mitigate corrosion, three primary methods are employed: (1) applying protective coatings like electroplating or dip coating to isolate the metal from water, (2) using electrochemical protection techniques such as sacrificial anodes (e.g., magnesium or zinc) or impressed current systems, and (3) adding corrosion inhibitors that form a stable, protective film on the metal surface. Pre-film treatments with higher concentrations of inhibitors are often applied before system operation to ensure effective protection.3. Microbial Growth:
In open-loop cooling water systems, water is typically returned to the cooling tower after passing through process equipment, where it cools via evaporation. This evaporation increases the concentration of organic matter, inorganic substances, and microorganisms in the water. The warm environment, combined with available nutrients, creates ideal conditions for microbial growth. Microbial activity leads to the formation of biofilms or slime, which reduce heat transfer efficiency, accelerate metal corrosion, and cause foul odors when sludge degrades. Slime-related failures often occur alongside scaling and corrosion. There are two main types of failure: (1) biofilm adhesion, where microbes and their byproducts accumulate on surfaces like pipes, walls, and packing materials, and (2) sludge buildup, where sediment settles in low-flow areas, forming soft deposits that clog equipment. These issues commonly occur in heat exchanger shells, distribution tanks, and pool bottoms.Dear Customer,
Thank you for your interest in Shanghai Jiapeng’s products. In addition to the cooling water treatment solutions we’ve discussed, our company also offers a range of advanced analytical instruments, including UV spectrophotometers, nucleic acid and protein detectors, gel imaging systems, photochemical reactors, constant current pumps, and automatic fraction collectors. These tools are widely used in research, environmental monitoring, and industrial applications. If you're looking for reliable and high-quality equipment, please feel free to reach out to us. We would be happy to provide more information or assist you in selecting the right product for your needs. Thank you again for considering Shanghai Jiapeng!Fuel Top Load Multipurpose Backpack,For Lady And Girl Foldable Travel Bag,Best Outdoor Travel Backpack,Outdoor Picnic Cooler Bagsdiy Bag
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