Corrosion and Scale Inhibitors: Protecting Industrial Water Systems

Industrial circulating water systems, boilers, and heat exchangers are important equipment in industrial production, but they are often affected by corrosion and scale formation, which lead to reduced equipment efficiency, shortened service life, and even safety accidents. Corrosion and scale inhibitors are specialized chemicals designed to solve these problems, which can effectively inhibit metal corrosion and scale deposition, ensuring the stable operation of industrial water systems. This article introduces the types, working mechanisms, and application scenarios of corrosion and scale inhibitors.

Corrosion inhibitors can be divided into inorganic corrosion inhibitors, organic corrosion inhibitors, and composite corrosion inhibitors. Inorganic corrosion inhibitors, such as chromates, nitrites, and phosphates, form a protective film on the metal surface through chemical reaction, isolating the metal from corrosive media such as oxygen and chloride ions. Organic corrosion inhibitors, including imidazolines, quaternary ammonium salts, and organic phosphonates, have good corrosion inhibition effect and low toxicity. They adsorb on the metal surface to form a dense adsorption film, preventing corrosion. Composite corrosion inhibitors combine the advantages of different types of corrosion inhibitors, improving corrosion inhibition efficiency and adapting to complex water quality conditions.

Scale inhibitors are mainly divided into phosphorus-containing scale inhibitors, phosphorus-free scale inhibitors, and composite scale inhibitors. Phosphorus-containing scale inhibitors, such as HEDP, ATMP, and PBTC, have h3 chelating ability and can effectively inhibit the formation of calcium carbonate, calcium sulfate, and other scales. However, the discharge of phosphorus-containing wastewater may cause water eutrophication, so phosphorus-free scale inhibitors, such as polyacrylic acid (PAA), polyepoxysuccinic acid (PESA), and polymaleic acid (PMA), have become the development trend. These phosphorus-free products are environmentally friendly, biodegradable, and have good scale inhibition effect in high-hardness water. In practical application, corrosion and scale inhibitors need to be selected according to the water quality of the system, equipment material, and operating conditions, and the dosage should be strictly controlled to avoid adverse effects.