High-efficiency corrosion inhibitor for sea water desalinization first-level reverse osmosis producing water

Abstract

The invention relates to a high-efficiency corrosion inhibitor for sea water desalinization first-level reverse osmosis producing water. One liter of high-efficiency corrosion inhibitor comprises 3 to 20 milligrams of sodium silicate (based on silicon dioxide (SiO2)), 30 to 50 milligrams of sodium hexametaphosphate, 2 to 4 milligrams of zinc sulfate (based on zinc ions (Zn<2+>)), 4 to 10 milligrams of sodium tungstate (based on tungstate ions (WO4<2->) and 2 to 5 milligrams of benzotriazole or methyl benzotriazole. By the high-efficiency corrosion inhibitor, the corrosion rates of the metal materials commonly used in a heat-engine plant, such as carbon steel, red copper and the like in the sea water desalinization first-level reverse osmosis producing water are reduced from 1.14007 mm / a to 0.04282 mm / a and from 0.06173 mm / a to 0.00606 mm / a respectively; the corrosion inhibition rates of the high-efficiency corrosion inhibitor on the carbon steel and the red copper are over 96.24 percent and 90.18 percent respectively; the corrosive action of the first-level reverse osmosis producing water on the materials is greatly relieved; and the tendency of the metal surface pitting is reduced, so that the service life of each of pipelines and equipment is greatly prolonged.

Description

technical field [0001] The invention relates to a high-efficiency corrosion inhibitor for seawater desalination primary reverse osmosis product water, belonging to the technical field of seawater desalination. Background technique [0002] With the increasing shortage of water resources and the general pollution of natural water bodies, the use of seawater desalination technology to obtain fresh water from seawater has attracted more and more attention from all over the world. Since the use of one-stage reverse osmosis can remove 99% of the salt in seawater, thereby obtaining valuable fresh water, which is more economical and reliable than other seawater desalination technologies, therefore, one-stage reverse osmosis technology has become a solution to the water supply problem in coastal areas. main method. As a large water user, thermal power plants consume a large amount of fresh water every year for equipment cooling, washing and other purposes. As the shortage of water...

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Problems solved by technology

[0003] At the same time, the corrosion problem of water produced by seawater desalination primary reverse osmosis has become increasingly prominent. In the water distribution pipe network of many thermal power plant seawater desalination primary reverse osmosis projects, carbon steel, copper and other materials have serious corrosion phenomena, and there are a large number of corrosion products in the pipes. , if the fresh water in the pipe is not used in time, the discharged water will be brownish yellow, which will not only seriously affect the water supply quality, but also directly threaten the safety of the water distribution network, and even threaten the normal and efficient operation of the entire power plant

[0004] At present, at home and abroad, the method of adding alkalizing agents such as sodium hydroxide to adjust the pH value or adding calcium, magnesium, and carbonate ions is mainly used to slow down the corrosion effect of seawater desalination primary reverse osmosis water on metal materials. The operation cost is high, the effect is not good, and the salt content in the water is greatly increased, especially after a large amount of hardness ions are introduced into the first-stage reverse osmosis product water of seawater desalination, there is a scaling tendency in the subsequent pipeline, which is not easy Suitable for popularization and application in thermal power plants

At present, some scholars (Liu Guangzhou, Wang Haitao, etc., a corrosion inhibitor for seawater desalination primary reverse osmosis water, publication number: CN101705489.A) use high phosphate corrosion inhibitor formula to alleviate seawater desalination primary reverse osmosis production. The corrosion effect of water on carbon steel has achieved certain results, but there are also the following problems: (1) phosphate is corrosive to copper and copper alloys, and for copper alloys such as copper that coexist in pipelines with carbon steel , will be corroded; (2) The corrosion inhibitor compounded with simple phosphate, zinc salt and other agents is easy to change color. The hanging test shows that the solution added with the corrosion inhibitor after 24 hours of hanging is light yellow, and the visual effect is not good. (3) The effect of this formula on inhibiting pitting corrosion on the surface of carbon steel is not obvious. After dynamic simulation of coupons, it is found that there are obvious pitting corrosion on the surface of carbon steel

The above three points also limit the scope of application of this type of high phosphate carbon steel corrosion inhibitor

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