Cooling circulating water accounts for more than 80% of the total industrial water consumption, and it occupies an important position in the industrial field. The use of chemical agents to treat is a means to achieve effective control of water saving, energy saving, environmental protection, corrosion inhibition, scale inhibition, sterilization, algae and scaling. With the advancement of technology, the use of electrochemical circulating water treatment technology can also achieve the effects of corrosion inhibition, scale inhibition, sterilization and algae killing. Therefore, chemical treatment and electrochemical treatment are two commonly used methods.
Cooling water circulation system In the cooling circulating water system, there may be problems of leakage, including equipment corrosion, scaling, microbial contamination and other problems, the following article is simply from the chemical treatment agent, the working principle of electrochemical treatment, scaling control, corrosion control, microbial control and other aspects to make a comparison, for the future treatment of cooling circulating water to provide a method.
1.How it works.
In the treatment of chemical agents, antiscalants, corrosion inhibitors, biodispersants, bactericidal algaecides, detergents, acid strippers, chlorination & chlorinators are commonly used to stabilize the mineral balance in water. For electrochemical treatment, its technology (EST, SCP, LPB) is usually used to adjust the balance of minerals in water by electrolysis to the electrochemical properties of water and minerals in water. What are Scale Inhibitors? What are the kinds? What is a polycarboxylic acid scale inhibitor and dispersantWhat is a flocculant? What is the mechanism of action? 2.Fouling control.
1) Antiscalants in chemical agents: increase the solubility of scaling minerals, prevent them from precipitating, or destroy the growth of calcium carbonate crystals, change the natural state of the sediment without adhering to the inner surface of the system. Dispersants and surfactants adsorb suspended solid particles, repelling each other and keeping the solid particles in a smaller particle state. Acids, phosphates, and water-soluble polymers are typical inorganic scale inhibitors, and scale control is especially critical at higher calcium hardness.
2) Electrochemical treatment of fouling is mainly to remove the pre-deposition of the cathode, reduce the total hardness in the system, and maintain the calcium carbonate in the cooling water in the dissolved state. In the case of silica scaling and high temperature of the heat exchanger surface, trace metal ions are released by electrolysis system to prevent silica precipitation and high-temperature precipitation of calcium carbonate. The suspended solids are unstable under the action of the electric field, flocculate and precipitate to the bottom of the reaction chamber, and are discharged from the system with the scale when washing and scraping.
3.Corrosion control.
1) It is one of the treatment methods of chemical agents to increase the pH value of cooling water, reduce the contact area of the metal surface with corrosion inhibitors, and block the electrochemical corrosion circuit to protect the metal surface. Phosphates, zinc salts, molybdates, and polysilicates are corrosion inhibitors for mild steels, while organic nitrogen-based compounds are corrosion inhibitors for copper materials.
2) Electrochemical treatment, like chemical agents, also needs to increase the pH value of cooling water to minimize the corrosiveness of water. Among them, magnesium will be deposited in the form of magnesium hydroxide on the inner wall of the pipe, which plays a role in corrosion inhibition and inhibition. Dissolved heavy metal ions (Fe2+, Cu2+, etc.) are deposited onto the cathode and removed along with scale.
4.Microbial control.
Surfactants, hydrogen peroxide, ozone and hypochlorite, and chlorine are all oxidizing agents that kill microorganisms. For electrochemical treatment, chloride ions in the circulating cooling water can be oxidized to form free chlorine or hypochlorous acid. At the same time, it can also kill microorganisms in the reaction chamber by strong current and alternately through strong alkali and strong acidic environment.
In general, chemical treatment and electrochemical treatment have their own advantages and disadvantages in the treatment of cooling circulating water. In practical application, it is necessary to choose the appropriate treatment method according to the specific situation. If a more efficient and environmentally friendly treatment method is required, electrochemical treatment can be considered. If a more flexible and simple treatment method is required, chemical treatment may be considered.