scale corrosion inhibitor ingredients
The main components of commonly used scale corrosion inhibitors for circulating water
Commonly used corrosion and scale inhibitors for circulating water are currently mainly compound products, which include corrosion inhibitor components, scale inhibitor components and dispersing components.
The function of corrosion inhibitor, namely corrosion inhibitor, is to inhibit the corrosion of metal and reduce the corrosion rate of metal.
Classification of scale corrosion inhibitors
According to the inhibited electrode reaction process, they are divided into anodic corrosion inhibitors, cathodic corrosion inhibitors and mixed corrosion inhibitors.
According to the type of protective film generated, it is divided into: oxide film type corrosion inhibitor, precipitation film type corrosion inhibitor and adsorption film type corrosion inhibitor.
Oxide film type scale corrosion inhibitor
It mainly oxidizes the metal surface and forms a protective film to inhibit metal corrosion. (Chromate) is toxic. When used alone, the initial concentration is 500-1000PPM, and the normal concentration is 200-250PPM. For economic and environmental reasons, the concentration is too high, so it is usually combined with other corrosion inhibitors (such as zinc salts) at lower dosages. , polyphosphate, organic phosphate), etc., are compounded to comply with the use of corrosion inhibitors. Due to the toxicity of chromium, chromate is not used as cooling water corrosion inhibitor or composite corrosion inhibitor in domestic open circulating cooling water systems. Nitrite is toxic and used in high concentrations. It can easily promote the growth of microorganisms in cooling water and may be reduced to ammonia, which can easily cause corrosion of copper and copper alloys.
Precipitation film type scale corrosion inhibitor
Reacts with relevant ions in the cooling water to form an anti-corrosion precipitation film on the metal surface. Mainly include zinc salts, silicates, etc.
Adsorption film type scale corrosion inhibitor
It is adsorbed on the metal surface and forms a shielding layer to inhibit metal corrosion. Mainly include methenamine and so on.
The main components of scale corrosion inhibitors
Corrosion inhibitors mainly include: chromate, nitrite, silicate, molybdate, zinc salt, phosphate, polyphosphate, organic phosphonic acid, etc., BTA (copper corrosion inhibitor, benzotriazole ).
Antiscalants mainly include: polyphosphate, organic phosphonic acid (ATMP/aminotrimethylene phosphonic acid, EDTMP/ethylenediamine tetramethylene phosphonic acid, HEDP/hydroxyethylene diphosphonic acid, DTPMP) phosphine carboxylic acid (PBTCA has both phosphate and carboxyl groups), organic phosphates (good at inhibiting calcium sulfate scale, but poor at inhibiting calcium carbonate scale), polycarboxylic acid
Dispersant: sulfonate copolymer (AA/AMPS), polycarboxylic acid
The corrosion and scale inhibitor content of the compound agent for circulating water is determined based on the quality of the circulating water, system materials, etc.