A nuclear grade polyacrylic acid, its preparation method and application

Abstract

This application discloses a nuclear-grade polyacrylic acid, its preparation method, and its applications. The nuclear-grade polyacrylic acid has a molecular weight of 100,000 to 200,000 and a sulfur content of 500 ppb to 1000 ppb. This nuclear-grade polyacrylic acid exhibits controllable molecular weight, good polydispersity, excellent scale inhibition performance, and a superior decomposition half-life. The molecular weight is controllable between 100,000 and 200,000, and the polydispersity is 1.0 to 3.5. The preparation method has a short cycle time and simple operation process; the preparation equipment is simple, and the preparation efficiency is high. The volume of the synthesis reactor used in the preparation can be adjusted according to the production volume, greatly improving the production efficiency. The preparation cost of this invention is low, and it is green, clean, and pollution-free. The raw materials used in the preparation process are inexpensive and readily available. The reactor involved only consumes a small amount of electricity, and the addition of a sulfur-free initiator and alcohol and ether-related solvents results in minimal environmental pollution.

Description

TECHNICAL FIELD

[0001] The application relates to a nuclear-grade polyacrylic acid and a preparation method and application thereof, and belongs to the technical field of scale inhibitor preparation. BACKGROUND

[0002] Scale inhibitors can effectively inhibit the formation of scale due to their chelation, dispersion, lattice distortion and other effects, and are widely used in the fields of seawater desalination, water circulation systems and the like. At present, scale inhibitors represented by natural polymer scale inhibitors, inorganic phosphate scale inhibitors, organic phosphonate scale inhibitors and environmentally friendly scale inhibitors are more popularized and applied in actual industrial production. Among the above-mentioned scale inhibitors, under the increasingly deepening of the green environmental protection concept, the natural polymer scale inhibitor and the environmentally friendly scale inhibitor become the ideal scale inhibitor material due to their relatively small pollution to the environment.

[0003] Among the environmentally friendly scale inhibitor materials, polyaspartic acid (PASP), polyepoxysuccinic acid (PESA) and acrylic acid (AA) and its derivatives have become a research hotspot in recent years. Among them, the scale inhibition rate of PASP on Ca 2+ is 80% when the concentration is 3 mg / L; the scale inhibition rate of PESP with a hyperbranched structure on calcium carbonate is 90% when the concentration is 15 mg / L; and the inhibition rate of AA on calcium carbonate is 80% when the concentration is 8 mg / L. Polyacrylic acid polymerized from AA has a regular molecular chain and is economically efficient, and has attracted widespread attention in the application field of industrial circulating cooling water systems. In particular, many components in the secondary circuit system of pressurized water reactor nuclear power plants, such as condensers, feedwater heaters, steam-water separation reheaters and the like, are mainly made of carbon steel, which is prone to corrosion during operation. The corrosion products produced by the corrosion of carbon steel equipment are transported with the feedwater and then deposited in the steam generator, which can cause many serious and harmful consequences, such as heat loss, heat transfer tube corrosion, thermal hydraulic instability, power output reduction and the like. Therefore, controlling the deposition of corrosion products is a key problem to ensure the performance and integrity of the steam generator. In order to alleviate the scaling phenomenon of the steam generator caused by the deposition of corrosion products, various strategies have been adopted in nuclear power plants at home and abroad, among which the polyacrylic acid dispersant has been tested in more than 20 pressurized water reactor units in the United States and other countries under full power, shutdown and start-up conditions, and has shown significant scale removal effect.

[0004] At present, among the polyacrylic acid materials reported in China, there are mainly two categories:

[0005] (1) With polyacrylic acid as the matrix, related improvements and application expansion in the synthesis process. For example, the method for preparing polyacrylic acid described in patent CN1324057C uses recycled heat medium to purify polyacrylic acid from an aqueous solution of acrylic acid or acrylic acid, which effectively utilizes latent heat and provides a new idea for low-carbon production; for example, the polyacrylic acid (salt), polyacrylic acid (salt) water-absorbing resin and its manufacturing method described in patent CN102858815B provides a water-absorbing resin containing a tracer and its manufacturing method, as well as a method for identifying and tracking the water-absorbing resin, which can trace the manufacturing process, consumer use, and various problems in the waste process by testing the tracer; for example, the manufacturing method of polyacrylic acid (salt) water-absorbing resin powder and polyacrylic acid (salt) water-absorbing resin powder described in patent CN104212105B provides a resin powder that combines liquid permeability and water absorption speed, with good application prospects; for example, the method for preparing polyacrylic acid or its copolymer and polyacrylic acid salt or its copolymer salt described in patent CN101921359B uses carbon-carbon unsaturated bonds and inorganic ingredients as raw materials to prepare organic polymers, which have the characteristics of low energy consumption, high equipment utilization, excellent product performance, safety, and environmental protection, and have good application prospects in dispersants and scale inhibitors, thickeners, and flocculants.

[0006] (2) Surface modification of polyacrylic acid to prepare composite materials and related applications. For example, the boron nitride nanosheet and polyacrylic acid gel composite thermal interface material and preparation method described in patent CN107573446B has excellent thermal conductivity and can be closely attached to the surface of various heat dissipation elements, with attractive application prospects in CPU and relay heat dissipation and conduction fields. For example, the preparation method of polypyrrole / polyacrylic acid composite gel electrolyte described in patent CN101714460B has high stability and high electrical conductivity, and has good application prospects in the fields of dye-sensitized solar cells, lithium ion batteries, and supercapacitors; for example, the wet polyurethane grafted polyacrylic acid copolymer resin for embossed leather and its preparation method described in patent CN101440151B has clear, full, and three-dimensional patterns, and the synthetic leather is easy to emboss. For example, the MWCNTs@polyacrylic acid@MOF-5 composite material and its preparation method described in patent CN104689801B have high specific surface area and good adsorption performance, and have good application prospects in cigarette filters.

[0007] At the same time, the traditional polyacrylic acid synthesis method inevitably has problems such as long preparation period, low yield, complicated preparation process, harsh preparation conditions, and use of sulfur-containing initiators. However, in the actual nuclear power plant secondary circuit water environment, the content of sulfur and other elements is strictly controlled. At present, there are almost no reports on the preparation of sulfur-free or low-sulfur polyacrylic acid and its application in the nuclear power field in China. In addition, the molecular weight of polyacrylic acid has a significant influence on the scale inhibition effect, and there are few reports on the influence of polyacrylic acid with different molecular weight levels on the scale inhibition performance. In particular, the preparation of low-sulfur high-molecular-weight polyacrylic acid scale inhibitor and its application in the secondary circuit of nuclear power plants are rarely reported. SUMMARY

[0008] According to one aspect of the present application, a nuclear-grade polyacrylic acid is provided.

[0009] The nuclear-grade polyacrylic acid has a controllable molecular weight of more than 100,000, good polydispersity, excellent scale inhibition performance, excellent decomposition half-life, potential for industrial production, and potential application and development value in the field of corrosion and scale inhibition in the secondary circuit of nuclear power plants.

[0010] A nuclear-grade polyacrylic acid has a molecular weight of 100,000 to 200,000, and the content of sulfur in the nuclear-grade polyacrylic acid is 500 ppb to 1000 ppb.

[0011] Optionally, the molecular weight of the nuclear-grade polyacrylic acid is independently selected from any value or a range value between any two of 100,000, 110,000, 120,000, 130,000, 140,000, 150,000, 160,000, 170,000, 180,000, 190,000, and 200,000.

[0012] Optionally, the content of sulfur in the nuclear-grade polyacrylic acid is independently selected from any value or a range value between any two of 500 ppb, 600 ppb, 700 ppb, 800 ppb, 900 ppb, and 1000 ppb.

[0013] Optionally, the molecular weight of the nuclear-grade polyacrylic acid is 120,000 to 200,000.

[0014] Optionally, the polydispersity of the nuclear-grade polyacrylic acid is 1.0 to 3.5.

[0015] Optionally, the polydispersity of the nuclear-grade polyacrylic acid is independently selected from any value or a range value between any two of 1.00, 1.50, 2.00, 2.10, 2.20, 2.30, 2.40, 2.48, 2.50, 2.60, 2.70, 2.80, 2.90, 3.00, 3.10, 3.20, 3.27, 3.30, 3.31, 3.40, 3.43, and 3.50.

[0016] According to another aspect of the present application, a method for preparing a nuclear-grade polyacrylic acid is provided.

[0017] The preparation cycle is short, the operation process is simple, the required preparation cycle is basically controlled within 24 hours, the operation process only includes steps of weighing, dissolving, mixing, heating, holding, reaction, precipitation, drying, etc., and is simple and easy to operate; the preparation equipment is simple, the preparation efficiency is high, the required equipment is common glassware and a reaction kettle in a laboratory, the volume of the synthetic reaction kettle used for preparation can be adjusted according to the yield, and the preparation efficiency is greatly improved; the preparation cost is low, green, clean and pollution-free, the raw materials are cheap and easy to obtain in the preparation process, only a small amount of electric energy is consumed for the reaction kettle, a sulfur-free initiator is added, and the related solvents of alcohol and ether have less environmental pollution.

[0018] A method for preparing a nuclear-grade polyacrylic acid, comprising the following steps:

[0019] Mixing and reacting a mixture containing acrylic acid monomer, initiator and organic solvent to obtain a nuclear-grade polyacrylic acid.

[0020] Optionally, the initiator is selected from at least one of dicumyl peroxide and hydrogen peroxide.

[0021] Optionally, the organic solvent is selected from at least one of ethylene glycol and isopropyl alcohol.

[0022] Optionally, the mass ratio of the organic solvent, the acrylic acid monomer and the initiator is 100-600:100:1.

[0023] Optionally, the mass ratio of the organic solvent, the acrylic acid monomer and the initiator is independently selected from any value or a range value between any two of 100:100:1, 200:100:1, 300:100:1, 350:100:1, 400:100:1, 450:100:1, 500:100:1, 550:100:1 and 600:100:1.

[0024] Optionally, the mixing time before the reaction is 0.5-2.5 hours.

[0025] Optionally, the reaction conditions are as follows:

[0026] The temperature is 60-100℃;

[0027] The time is 4-10 hours.

[0028] Optionally, the temperature is independently selected from any value or a range value between any two of 60℃, 65℃, 70℃, 75℃, 78℃, 80℃, 82℃, 85℃, 86℃, 88℃, 90℃, 92℃, 95℃ and 100℃.

[0029] Optionally, the time is independently selected from any value in 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h or a range value between any two of them.

[0030] Optionally, the reaction is carried out under inert gas.

[0031] Optionally, after the reaction, the product is mixed with ethylene glycol methyl ether.

[0032] Optionally, the mass ratio of the product to ethylene glycol methyl ether is 1:3-5.

[0033] According to the third aspect of the present application, there is provided an application of the nuclear grade polyacrylic acid as a scale inhibitor.

[0034] The scale inhibitor made of the nuclear grade polyacrylic acid has excellent scale inhibition performance and excellent decomposition half-life.

[0035] A nuclear grade polyacrylic acid scale inhibitor, wherein the nuclear grade polyacrylic acid is obtained by crushing the nuclear grade polyacrylic acid; the nuclear grade polyacrylic acid is selected from the nuclear grade polyacrylic acid and / or the nuclear grade polyacrylic acid obtained by the preparation method.

[0036] The beneficial effects that can be produced by the present application include:

[0037] 1) The nuclear grade polyacrylic acid provided by the present application has controllable molecular weight, good polydispersity, excellent scale inhibition performance, and excellent decomposition half-life. The molecular weight can be controlled to 100-200 thousand, and the polydispersity is 1.0-3.5.

[0038] 2) The preparation period provided by the present application is relatively short, and the operation process is simple. The required preparation period is basically controlled within 24h, and the operation process only includes the steps of weighing, dissolving, mixing, heating, insulation, reaction, precipitation, and drying, which is simple and easy to operate; the preparation equipment is simple, and the preparation efficiency is relatively high. The required equipment is commonly used glassware and reaction kettle in the laboratory, and the volume of the synthesis reaction kettle used for preparation can be adjusted according to the yield, which greatly improves the preparation efficiency.

[0039] 3) The preparation cost of the present application is relatively low, green, clean and pollution-free. The raw materials in the preparation process are cheap and easy to obtain, the reaction kettle involved only consumes a small amount of electric energy, and the addition of sulfur-free initiator and alcohol and ether related solvents has less environmental pollution. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The infrared spectrum of the polyacrylic acid in Example 1 of the present application.

[0041] Figure 2 The scanning electron microscope image of the polyacrylic acid in Example 1 of the present application.

[0042] Figure 3 The picture of the scale inhibition performance of the polyacrylic acid of Example 1 of the application.

[0043] Figure 4 The picture of the summary of the molecular weight and dispersity of the polyacrylic acid of Examples 1-5 of the application. DETAILED DESCRIPTION

[0044] The application will be described in detail below with reference to the examples, but the application is not limited to these examples.

[0045] The raw materials in the examples of the application are all purchased through commercial channels unless otherwise specified.

[0046] The analysis methods in the examples of the application are as follows:

[0047] Spectral analysis is performed by using Fourier infrared spectroscopy.

[0048] Electron microscopy analysis is performed by using field emission scanning electron microscopy.

[0049] Scale inhibition performance analysis is performed by using a spectrophotometer.

[0050] Example 1

[0051] 200 g of isopropyl alcohol, 100 g of acrylic acid monomer, and 1 g of dicumyl peroxide are weighed and slowly added to a reaction kettle for uniform mixing for 0.5 hours. Under the protection of high-purity argon, it is slowly heated to 65°C and kept at this temperature for 4 hours. Then, 50 g of the generated product is poured into 50 g of ethylene glycol methyl ether solvent, and polyacrylic acid solids are precipitated. Next, the precipitated polyacrylic acid is dried at 70°C for 4 hours, then taken out and crushed, and then dried for another 8 hours. Finally, the formed polyacrylic acid solid powder is the core-level polyacrylic acid scale inhibitor.

[0052] Figure 1 The infrared spectrum of the polyacrylic acid of this Example 1 is shown in the figure, and the characteristic peak positions in the figure all correspond to the characteristic peaks of polyacrylic acid, indicating that pure polyacrylic acid has been successfully prepared. Figure 2 The optical microscopic picture of this example case. Figure 3 The scale inhibition performance picture of this Example 1, wherein the scale inhibition test takes the common PWR nuclear power plant secondary circuit system corrosion product oxide Fe3O4 as an example to investigate the dispersion effect of the polyacrylic acid prepared by the application.

[0053] Example 2

[0054] Take 300g of isopropyl alcohol, 100g of acrylic acid monomer, 1g of dicumyl peroxide, slowly add to the reaction kettle and mix evenly for 1 hour. Under the protection of high-purity argon, slowly heat to 75°C, and keep the temperature constant for 6 hours. Then, take 50g of the generated product and pour it into 100g of ethylene glycol methyl ether solvent, and the polyacrylic acid solid is precipitated. Next, the precipitated polyacrylic acid is dried at 75°C for 5 hours, then taken out and crushed, and then dried for another 7 hours. Finally, the formed polyacrylic acid solid powder is the core level polyacrylic acid scale inhibitor.

[0055] Example 3

[0056] Take 400g of isopropyl alcohol, 100g of acrylic acid monomer, 1g of hydrogen peroxide, slowly add to the reaction kettle and mix evenly for 1.5 hours. Under the protection of high-purity argon, slowly heat to 80°C, and keep the temperature constant for 8 hours. Then, take 50g of the generated product and pour it into 150g of ethylene glycol methyl ether solvent, and the polyacrylic acid solid is precipitated. Next, the precipitated polyacrylic acid is dried at 80°C for 6 hours, then taken out and crushed, and then dried for another 6 hours. Finally, the formed polyacrylic acid solid powder is the core level polyacrylic acid scale inhibitor.

[0057] Example 4

[0058] Take 500g of isopropyl alcohol, 100g of acrylic acid monomer, 1g of dicumyl peroxide, slowly add to the reaction kettle and mix evenly for 2 hours. Under the protection of high-purity argon, slowly heat to 85°C, and keep the temperature constant for 9 hours. Then, take 50g of the generated product and pour it into 200g of ethylene glycol methyl ether solvent, and the polyacrylic acid solid is precipitated. Next, the precipitated polyacrylic acid is dried at 85°C for 7 hours, then taken out and crushed, and then dried for another 5 hours. Finally, the formed polyacrylic acid solid powder is the core level polyacrylic acid scale inhibitor.

[0059] Example 5

[0060] Take 600g of isopropyl alcohol, 100g of acrylic acid monomer, 1g of hydrogen peroxide, slowly add to the reaction kettle and mix evenly for 2.5 hours. Under the protection of high-purity argon, slowly heat to 90°C, and keep the temperature constant for 10 hours. Then, take 50g of the generated product and pour it into 250g of ethylene glycol methyl ether solvent, and the polyacrylic acid solid is precipitated. Next, the precipitated polyacrylic acid is dried at 90°C for 8 hours, then taken out and crushed, and then dried for another 4 hours. Finally, the formed polyacrylic acid solid powder is the core level polyacrylic acid scale inhibitor.

[0061] Figure 4 The molecular weight and dispersity of the polyacrylic acid of Examples 1-5 are summarized in the following table. As can be seen from the table, the molecular weight distribution is 100,000-200,000, and the polydispersity is 1.0-3.5.

[0062] The above merely describes several embodiments of the present application, and does not limit the present application in any form. Although the present application is disclosed with the preferred embodiments, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the disclosed technical contents without departing from the scope of the technical solutions of the present application, and the equivalent embodiments are equivalent to the equivalent embodiments, which are within the scope of the technical solutions.

Claims

1. A nuclear grade polyacrylic acid scale inhibitor characterized in that, The core-level polyacrylic acid is crushed to obtain the core-level polyacrylic acid scale inhibitor; The core-level polyacrylic acid has a molecular weight of 100,000-200,000, and the content of sulfur in the core-level polyacrylic acid is 500 ppb-1000 ppb; The preparation method of the core-level polyacrylic acid comprises the following steps: a mixed solution containing an acrylic acid monomer, an initiator and an organic solvent is reacted under an inert gas, and after the reaction, the product is mixed with ethylene glycol methyl ether, and then precipitation is performed to obtain the core-level polyacrylic acid. The initiator is at least one selected from hydrogen peroxide and dicumyl peroxide. The polydispersity of the core-level polyacrylic acid is 1.0-3.

5.

2. The nuclear grade polyacrylic acid scale inhibitor of claim 1, wherein, The core-level polyacrylic acid has a molecular weight of 120,000-200,000.

3. The nuclear grade polyacrylic acid scale inhibitor of claim 1, wherein, The organic solvent is at least one selected from ethylene glycol and isopropyl alcohol.

4. The nuclear grade polyacrylic acid scale inhibitor of claim 1, wherein, The mass ratio of the organic solvent, the acrylic acid monomer and the initiator is 100-600:100:

1.

5. The nuclear grade polyacrylic acid scale control agent of claim 1, wherein, The reaction conditions are as follows: The temperature is 60-100 DEG C. The time is 4-10 hours.

6. The nuclear grade polyacrylic acid scale control agent of claim 1, wherein, The reaction is performed under an inert gas.

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