The present disclosure provides a pressure-reducing and injection-enhancing anti-scaling agent for low-permeability water-injection wells and a preparation method thereof. The anti-scaling agent is prepared from starting materials comprising: 10 to 12 parts of non-ionic surfactant(s), 18 to 20 parts of hexasodium triethylenetetramine-N,N,N,N,N,N-hexaacetate, 5 to 8 parts of anionic surfactant(s), 6 to 8 parts of an organic phosphonic acid-carboxylic acid scale inhibitor, 2 to 5 parts of a dispersant, 15 to 18 parts of a diluent, 8 to 10 parts of an organic amine salt, and 30 to 36 parts of water. The pressure-reducing and injection-enhancing agent according to the present disclosure is characterized by having multiple functions in one agent. When used in an amount being 0.5% of the water injected to a water injection well, it shows excellent anti-swelling property, shrinking property, anti-corrosive property, and calcium sulfate and barium (strontium) sulfate scale resistance.

To provide a corrosion mitigation method for carbon steel pipe that can further reduce corrosion of the carbon steel pipe. In a BWR plant, oxygen is injected from an oxygen injection device 30 into a clean up system pipe 18 which is constituted by a Cr-containing carbon steel pipe containing Cr in a range of larger than 0.052 wt % and less than 0.4 wt % and being in communication with a RPV 3, and reactor water of 150 C. having a dissolved oxygen concentration of 30 g/L is generated. The reactor water is brought into contact with an inner surface of the clean up system pipe 18 to perform an oxidizing treatment on the inner surface, and an oxide film containing Cr is formed on the inner surface. Thus, after the oxide film is formed, hydrogen is injected into the reactor water in the RPV 3 through a water supply pipe 11 in communication with to the RPV 3, and even when the dissolved oxygen concentration in the reactor water in contact with the inner surface of the clean up system pipe 18 is reduced to 2 g/L, corrosion of the clean up system pipe 18 is remarkably mitigated.

To provide a corrosion mitigation method for carbon steel pipe that can further reduce corrosion of the carbon steel pipe. In a BWR plant, oxygen is injected from an oxygen injection device 30 into a clean up system pipe 18 which is constituted by a Cr-containing carbon steel pipe containing Cr in a range of larger than 0.052 wt % and less than 0.4 wt % and being in communication with a RPV 3, and reactor water of 150 C. having a dissolved oxygen concentration of 30 g/L is generated. The reactor water is brought into contact with an inner surface of the clean up system pipe 18 to perform an oxidizing treatment on the inner surface, and an oxide film containing Cr is formed on the inner surface. Thus, after the oxide film is formed, hydrogen is injected into the reactor water in the RPV 3 through a water supply pipe 11 in communication with to the RPV 3, and even when the dissolved oxygen concentration in the reactor water in contact with the inner surface of the clean up system pipe 18 is reduced to 2 g/L, corrosion of the clean up system pipe 18 is remarkably mitigated.

The present invention provides a carboxyl group-containing copolymer having a better calcium ion trapping ability and a better carbon black dispersing ability than any conventional carboxyl group-containing copolymers. The present invention relates to a carboxyl group-containing copolymer including a structural unit (a) derived from an unsaturated monocarboxylic acid monomer (A), a structural unit (b) derived from an unsaturated dicarboxylic acid monomer (B), and a structural unit (c) derived from a cationic monomer (C).

Glycine is an organic compound that can be used in the making of a synthetic acid that obviates all the drawbacks of strong acids such as hydrochloric acid. The new compound is made by dissolving glycine in water, in a weight ratio of approximately 1:1 to 1:1.5. The solution is mixed until the glycine is essentially fully dissolved in the water. Once dissolution is complete, hydrogen chloride gas is dissolved in the solution to produce the new compound, which can be referred to as hydrogen glycine. Also disclosed is a method for adjusting the pH of a fluid, the method comprising adding an effective amount of a solution to the fluid for adjusting the pH thereof to a desired level, wherein the solution is prepared by mixing glycine in water to form a glycine solution; and adding hydrogen chloride to the glycine solution.

A scale remover that efficiently removes scale deposited inside a boiler without corroding a boiler includes polyacrylic acid and polymethacrylic acid and/or salts thereof.

A scale remover that efficiently removes scale deposited inside a boiler without corroding a boiler includes polyacrylic acid and polymethacrylic acid and/or salts thereof.

An additive comprising one or more C.sub.3-C.sub.12 hydroxycarboxylic acids and/or one or more C.sub.3-C.sub.12 hydroxycarboxylic acid salts may be added to an aqueous system having galvanized metallurgy or a carbon steel surface in an effective amount to passivate a galvanized coating on the metallurgy or to decrease white rust formation or other types of corrosion upon the galvanized metallurgy or carbon steel surface in an aqueous system. In a non-limiting embodiment, the C.sub.3-C.sub.12 hydroxycarboxylic acid or the C.sub.3-C.sub.12 hydroxycarboxylic acid salt additive may utilize the zinc in the galvanized coating to achieve passivation. The passivation may occur while the system is shut down or in service. The aqueous system may be or include a cooling tower, a cooling water system, and combinations thereof. The additive may be used with or in the absence of a phosphorous-containing compound.

Disclosed herein are compositions and methods of mitigating scale in phosphoric acid and ammonium phosphate plants. Scale-mitigating compositions of the invention can be added to phosphoric acid before or during the concentration in the evaporator cycle of a phosphoric acid plant. The compositions retard the formation of scale on surfaces in contact with the phosphoric acid, and thus time between cleaning is extended and plant productivity increased. Further, the scale that forms is softer and more easily cleaned from surfaces, reducing non-operation time of the plant and/or evaporator. Methods of mitigating scale formation in phosphoric acid production and phosphoric acid handling plants are disclosed. In the methods, scales accumulate more slowly and are softer, more tractable, and more easily cleaned from surfaces to which they adhere.

Disclosed herein are compositions and methods of mitigating scale in phosphoric acid and ammonium phosphate plants. Scale-mitigating compositions of the invention can be added to phosphoric acid before or during the concentration in the evaporator cycle of a phosphoric acid plant. The compositions retard the formation of scale on surfaces in contact with the phosphoric acid, and thus time between cleaning is extended and plant productivity increased. Further, the scale that forms is softer and more easily cleaned from surfaces, reducing non-operation time of the plant and/or evaporator. Methods of mitigating scale formation in phosphoric acid production and phosphoric acid handling plants are disclosed. In the methods, scales accumulate more slowly and are softer, more tractable, and more easily cleaned from surfaces to which they adhere.