A wet-process phosphoric acid multifunctional high-efficiency scale inhibitor and a preparation method and application thereof

Abstract

The application discloses a wet-process phosphoric acid multifunctional efficient scale inhibitor as well as a preparation method and application thereof, and comprises the following raw materials in parts by weight: phosphamide compounds 20-25 parts; 18-crown-6 15-20 parts; glyceryl monolaurate 5-10 parts; a surfactant 10-15 parts; an inhibitor 5-10 parts; an organic solvent 20-45 parts; the scale inhibitor provided by the application has multiple functions, can cope with different types of scale layers, can be used for scale inhibition in various scenes such as industrial equipment, pipelines and heat exchangers, has strong scale inhibition capacity, has not only a scale removal function but also a long-acting scale prevention capacity. In addition, the scale inhibitor has a small addition amount and low use cost.

Description

Technical Field

[0001] This invention relates to the field of wet-process phosphoric acid scale inhibitor technology, and in particular to a multifunctional high-efficiency scale inhibitor for wet-process phosphoric acid, its preparation method, and its application. Background Technology

[0002] Wet-process phosphoric acid production includes acidolysis, filtration, concentration, pretreatment, and defluorination. During phosphoric acid concentration and defluorination, changes in temperature and concentration cause a large amount of soluble salts to precipitate and adhere to the surface of graphite heat exchangers, forming scale and causing blockage, severely affecting heat exchange efficiency. The scale precipitated during concentration is mostly hemihydrate calcium sulfate, with some phosphates and small amounts of sodium, potassium, and magnesium fluorosilicates. During defluorination, due to the addition of excessive defluorinating agent, the scale adhering to the graphite heat exchanger contains approximately 70% fluorosilicate, about 10% hemihydrate calcium sulfate, and the remainder phosphates. Because this scale is highly viscous, it easily adheres to the graphite heat exchanger surface, forming hard scale. This results in the defluorination graphite heat exchanger operating continuously for no more than 8 days, and the scale is difficult to remove, significantly increasing production, operation, and maintenance costs, which is extremely detrimental to wet-process phosphoric acid production.

[0003] Currently, there are many types of scale inhibitors used in the wet-process phosphoric acid production field, such as the wet-process phosphoric acid concentration scale inhibitors disclosed in application numbers CN202211082919.0 and CN201811485389.8, the wet-process phosphoric acid production scale inhibitor disclosed in application number CN201810732057.9, and the wet-process phosphoric acid pipeline scale inhibitor disclosed in application number CN201810732057.9, etc. However, these scale inhibitors are used in large quantities and are mostly only suitable for single operating conditions. The effectiveness of scale inhibition varies significantly depending on operating conditions. Furthermore, long-term equipment testing and use have revealed that currently available scale inhibitors are effective for scale inhibition in pipelines and during the first stage of wet-process phosphoric acid concentration (P2O5 concentration of 40%–42%), extending the equipment's operating cycle to over 30 days. However, under conditions of higher temperatures and concentrations (above 90℃, P2O5 concentration above 50%), or with the addition of defluorinating agents, these scale inhibitors are ineffective, making it difficult to exceed 15 days for the equipment's operating cycle. Therefore, further research and development of a multifunctional and highly efficient wet-process phosphoric acid scale inhibitor are needed to improve its adaptability and efficiency under different conditions. Summary of the Invention

[0004] This invention provides a wet-process phosphoric acid multifunctional high-efficiency scale inhibitor, its preparation method, and its application.

[0005] The solution of the present invention is:

[0006] A multifunctional and highly efficient scale inhibitor using wet-process phosphoric acid comprises the following raw materials in parts by weight:

[0007]

[0008]

[0009] As a preferred technical solution, the phosphoramide compound is one of phenylphosphine diamide and diethylpyrophosphine. The phosphoramide compound is a commercially available product of Henan Alpha Chemical Co., Ltd., under the Alpha brand.

[0010] As a preferred technical solution, the surfactant is one or more selected from fatty amine polyoxyethylene ether, polyethylene glycol-propylene glycol copolymer, polyoxyethylene alkylamine, and polyoxyethylene stearyl alcohol ether. The polyethylene glycol-propylene glycol copolymer is commercially available, a product of Hubei Rishengchang New Material Technology Co., Ltd., under the brand name "Rishengchang".

[0011] As a preferred technical solution, the corrosion inhibitor is dilauryl glycerol sulfate.

[0012] As a preferred technical solution, the organic solvent is one or more of ethylene glycol dimethyl ether, n-propylene glycol, sec-butanol, and ethylene glycol ether.

[0013] This invention also discloses a method for preparing a multifunctional and highly efficient scale inhibitor using wet-process phosphoric acid, comprising the following steps:

[0014] 1) Weigh 20-45 parts by weight of organic solvent and place it in a reaction vessel at a constant temperature of 50-60℃;

[0015] 2) Weigh 20-25 parts by weight of phosphoramide compound, 15-20 parts by weight of 18-crown ether-6, 5-10 parts by weight of glyceryl monocitrate, 10-15 parts by weight of surfactant, and 5-10 parts by weight of corrosion inhibitor, and add them to the reaction vessel in sequence.

[0016] 3) The wet-process phosphoric acid high-efficiency scale inhibitor is prepared by stirring each component under constant temperature for 30-40 minutes.

[0017] This invention also discloses the application of a wet-process phosphoric acid multifunctional high-efficiency scale inhibitor. The wet-process phosphoric acid multifunctional high-efficiency scale inhibitor can be used for scale inhibition in pipelines and heat exchangers under different operating conditions and temperatures. It is added directly to phosphoric acid during use, with a dosage of 15-25 ppm.

[0018] As a preferred technical solution, the wet-process phosphoric acid multifunctional high-efficiency scale inhibitor is used at a dosage of 20 ppm for pipeline scale inhibition and 25 ppm for heat exchanger scale inhibition.

[0019] A multifunctional and highly efficient wet-process phosphoric acid scale inhibitor, its preparation method, and its application, comprising the following raw materials in parts by weight: 20-25 parts of phosphoramide compounds; 15-20 parts of 18-crown ether-6; 5-10 parts of glyceryl monocitrate; 10-15 parts of surfactant; 5-10 parts of corrosion inhibitor; and 20-45 parts of organic solvent.

[0020] The principle of this invention is to achieve the best scale inhibition effect through the synergistic effect of the complexing, surface activation, encapsulation, dispersion, corrosion inhibition, viscosity reduction and solubilization properties of various organic substances.

[0021] In the scale inhibitor of this invention, both phosphoramide compounds and 18-crown ether-6 have strong complexing properties and react with Ca. 2+ Fe 3+ Mg 2+ Al 3+ Na + K + When metal ions form stable soluble complexes, phosphoramide compounds bind with Ca. 2+ Fe 3 + Mg 2+ Al 3+ It has a strong ability to inhibit the formation of calcium sulfate, phosphate, and some fluorosilicate scale. 18-crown ether-6 can react with most Na+. + K + The complexation with metal ions inhibits the precipitation of most sodium and potassium fluorosilicates, thus reducing scale formation. Citrate monoglyceride enhances the selectivity and effectiveness of the complexation reaction between phosphoramide compounds and 18-crown ether-6 through coordination and steric hindrance. Surfactants in this scale inhibitor reduce the surface tension of the liquid through surface modification, allowing for better wetting of the scale surface, promoting contact between the scale inhibitor and the scale, and forming a thin film on the surface of solid particles to disperse them and prevent scale aggregation. Corrosion inhibitors form a protective film on the surface of equipment or pipes, preventing solid particles from adhering to form scale. Organic solvents in this scale inhibitor reduce viscosity and increase solubility, lowering the liquid viscosity and increasing the solubility of the aqueous solution. This promotes the reaction between the scale inhibitor and scale-forming substances in the water, dissolving or dispersing them, thereby reducing the deposition rate of scale in pipes and equipment, slowing down scale formation and growth, improving the effectiveness of the scale inhibitor, and accelerating scale dissolution and removal.

[0022] The scale inhibitor of this invention significantly reduces scale formation during wet-process phosphoric acid production through multi-effect synergistic action, achieving efficient scale inhibition and removal. All components of the scale inhibitor of this invention possess excellent temperature resistance, maintaining good stability below 110℃, ensuring that scale inhibition performance is unaffected under higher temperature conditions.

[0023] Advantages of this invention:

[0024] The scale inhibitor of this invention uses environmentally friendly raw materials and formula, contains no harmful substances, and due to the addition of organic solvents, the components mix quickly and have excellent mixing performance in acid or aqueous solutions. It can be used under various operating temperature conditions.

[0025] Compared with existing technologies, the scale inhibitor provided by this invention has multiple functions, can deal with different types of scale layers, and can be used for scale inhibition in various scenarios such as industrial equipment, pipelines, and heat exchangers. It also exhibits strong scale inhibition capabilities, not only removing scale but also providing long-lasting scale prevention. Furthermore, this scale inhibitor requires a small dosage, resulting in lower usage costs. Detailed Implementation

[0026] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0027] Example 1:

[0028] Weigh 45 parts by weight of ethylene glycol dimethyl ether and place it in a reactor at 50°C for constant temperature. Then weigh 20 parts by weight of phenylphosphamide, 15 parts by weight of 18-crown ether-6, 5 parts by weight of glyceryl monocitrate, 10 parts by weight of fatty amine polyoxyethylene ether, and 5 parts by weight of dilauryl glycerol sulfate, and add them to the reactor in sequence. Stir for 30 minutes under constant temperature conditions to obtain a wet-process phosphoric acid scale inhibitor.

[0029] When the scale inhibitor is added directly at a dosage of 20 ppm to phosphoric acid pipelines with an operating temperature of 50–70°C, the start-up period is extended from 18 days without the scale inhibitor to 30 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid concentration heat exchangers with an operating temperature of 75–85°C, the start-up period is extended from 12 days without the scale inhibitor to 23 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid defluorination heat exchangers with an operating temperature of 95–105°C, the start-up period is extended from 8 days without the scale inhibitor to 15 days.

[0030] Example 2:

[0031] Weigh 40 parts by weight of n-propylene glycol and place it in a reactor at 55°C for constant temperature. Weigh 25 parts by weight of diethyl pyrophosphoramide, 15 parts by weight of 18-crown ether-6, 5 parts by weight of glyceryl citrate monoester, 10 parts by weight of polyethylene glycol propylene glycol copolymer, and 5 parts by weight of dilauryl glyceryl sulfate, and add them to the reactor in sequence. Stir for 30 minutes under constant temperature conditions to obtain a wet-process phosphoric acid scale inhibitor.

[0032] When the scale inhibitor is added directly at a dosage of 20 ppm to phosphoric acid pipelines with an operating temperature of 50–70°C, the start-up period is extended from 18 days without the scale inhibitor to 32 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid concentration heat exchangers with an operating temperature of 75–85°C, the start-up period is extended from 12 days without the scale inhibitor to 25 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid defluorination heat exchangers with an operating temperature of 95–105°C, the start-up period is extended from 8 days without the scale inhibitor to 16 days.

[0033] Example 3:

[0034] Weigh 35 parts by weight of sec-butanol and place it in a reactor at 60℃ for constant temperature. Then weigh 25 parts by weight of phenylphosphamide, 20 parts by weight of 18-crown ether-6, 5 parts by weight of glyceryl monocitrate, 10 parts by weight of polyoxyethylene alkylamine, and 5 parts by weight of dilauryl glycerol sulfate, and add them to the reactor in sequence. Stir for 30 minutes under constant temperature conditions to obtain a wet-process phosphoric acid scale inhibitor.

[0035] When the scale inhibitor is added directly at a dosage of 20 ppm to phosphoric acid pipelines with an operating temperature of 50–70°C, the start-up period is extended from 18 days without the scale inhibitor to 33 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid concentration heat exchangers with an operating temperature of 75–85°C, the start-up period is extended from 12 days without the scale inhibitor to 27 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid defluorination heat exchangers with an operating temperature of 95–105°C, the start-up period is extended from 8 days without the scale inhibitor to 18 days.

[0036] Example 4:

[0037] Weigh 30 parts by weight of ethylene glycol ether and place it in a reactor at 60℃ for constant temperature. Then weigh 25 parts by weight of phenylphosphamide, 20 parts by weight of 18-crown ether-6, 10 parts by weight of glyceryl monocitrate, 10 parts by weight of polyoxyethylene stearyl ether, and 5 parts by weight of dilauryl glyceryl sulfate, and add them to the reactor in sequence. Stir for 30 minutes under constant temperature conditions to obtain a wet-process phosphoric acid scale inhibitor.

[0038] When the scale inhibitor is added directly at a dosage of 20 ppm to phosphoric acid pipelines with an operating temperature of 50–70°C, the start-up period is extended from 18 days without the scale inhibitor to 35 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid concentration heat exchangers with an operating temperature of 75–85°C, the start-up period is extended from 12 days without the scale inhibitor to 31 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid defluorination heat exchangers with an operating temperature of 95–105°C, the start-up period is extended from 8 days without the scale inhibitor to 21 days.

[0039] Example 5:

[0040] Weigh 25 parts by weight of n-propylene glycol and place it in a reaction vessel at 60℃ for constant temperature. Then weigh 25 parts by weight of phenylphosphamide, 20 parts by weight of 18-crown ether-6, 10 parts by weight of glyceryl monocitrate, 15 parts by weight of polyoxyethylene alkylamine, and 5 parts by weight of dilauryl glyceryl sulfate, and add them to the reaction vessel in sequence. Stir for 30 minutes under constant temperature conditions to obtain a wet-process phosphoric acid scale inhibitor.

[0041] When the scale inhibitor is added directly at a dosage of 20 ppm to phosphoric acid pipelines with an operating temperature of 50–70°C, the start-up period is extended from 18 days without the scale inhibitor to 36 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid concentration heat exchangers with an operating temperature of 75–85°C, the start-up period is extended from 12 days without the scale inhibitor to 29 days. When the scale inhibitor is added directly at a dosage of 20 ppm to phosphoric acid defluorination heat exchangers with an operating temperature of 95–105°C, the start-up period is extended from 8 days without the scale inhibitor to 20 days.

[0042] Example 6:

[0043] Weigh 20 parts by weight of n-propylene glycol and place it in a reactor at 60℃ for constant temperature. Then weigh 25 parts by weight of phenylphosphamide, 20 parts by weight of 18-crown ether-6, 10 parts by weight of glyceryl monocitrate, 15 parts by weight of polyoxyethylene alkylamine, and 10 parts by weight of dilauryl glycerol sulfate, and add them to the reactor in sequence. Stir for 30 minutes under constant temperature to obtain a wet-process phosphoric acid scale inhibitor.

[0044] When the scale inhibitor is added directly at a dosage of 20 ppm to phosphoric acid pipelines with an operating temperature of 50–70°C, the start-up period is extended from 18 days without the scale inhibitor to 38 days. When the scale inhibitor is added directly at a dosage of 25 ppm to phosphoric acid concentration heat exchangers with an operating temperature of 75–85°C, the start-up period is extended from 12 days without the scale inhibitor to 29 days. When the scale inhibitor is added directly at a dosage of 20 ppm to phosphoric acid defluorination heat exchangers with an operating temperature of 95–105°C, the start-up period is extended from 8 days without the scale inhibitor to 19 days.

[0045] The products produced in Examples 1 to 6 were tested respectively, and the experimental results are evaluated as shown in Table 1 below.

[0046] Table 1: Evaluation of the scale inhibition effect of scale inhibitors in experimental tests

[0047]

[0048]

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A multifunctional and highly efficient scale inhibitor using wet-process phosphoric acid, characterized in that, The following ingredients are included in parts by weight: 20-25 parts of phosphoramide compounds; 18-crown ether-6 15-20 parts; 5-10 parts of glyceryl monocitrate; 10-15 parts of surfactant; 5-10 parts corrosion inhibitor; 20-45 parts organic solvent.

2. The wet-process phosphoric acid multifunctional high-efficiency scale inhibitor as described in claim 1, characterized in that: The phosphoramide compound is one of phenylphosphine and diethylpyrophosphine.

3. The wet-process phosphoric acid multifunctional high-efficiency scale inhibitor as described in claim 1, characterized in that: The surfactant is one or more of the following: fatty amine polyoxyethylene ether, polyethylene glycol propylene glycol copolymer, polyoxyethylene alkylamine, and polyoxyethylene stearyl alcohol ether.

4. The wet-process phosphoric acid multifunctional high-efficiency scale inhibitor as described in claim 1, characterized in that: The corrosion inhibitor is dilauryl glycerol sulfate.

5. The wet-process phosphoric acid multifunctional high-efficiency scale inhibitor as described in claim 1, characterized in that: The organic solvent is one or more of ethylene glycol dimethyl ether, n-propylene glycol, sec-butanol, and ethylene glycol ether.

6. A method for preparing the wet-process phosphoric acid multifunctional high-efficiency scale inhibitor as described in any one of claims 1 to 5, characterized in that, Includes the following steps: 1) Weigh 20-45 parts by weight of organic solvent and place it in a reaction vessel at a constant temperature of 50-60℃; 2) Weigh 20-25 parts by weight of phosphoramide compound, 15-20 parts by weight of 18-crown ether-6, 5-10 parts by weight of glyceryl monocitrate, 10-15 parts by weight of surfactant, and 5-10 parts by weight of corrosion inhibitor, and add them to the reaction vessel in sequence. 3) The wet-process phosphoric acid high-efficiency scale inhibitor is prepared by stirring each component under constant temperature for 30-40 minutes.

7. The application of a multifunctional high-efficiency scale inhibitor for wet-process phosphoric acid as described in any one of claims 1 to 5, characterized in that: This wet-process phosphoric acid multifunctional high-efficiency scale inhibitor can be used for scale inhibition in pipelines and heat exchangers under different operating conditions and temperatures. It is added directly to phosphoric acid at a dosage of 15-25 ppm.

8. The application as described in claim 7, characterized in that: The wet-process phosphoric acid multifunctional high-efficiency scale inhibitor is used at a dosage of 20 ppm for pipeline scale inhibition and 25 ppm for heat exchanger scale inhibition.

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