Coal chemical industry wastewater reverse osmosis high-silicon-resistant scale inhibitor and application thereof

Abstract

The invention provides a reverse osmosis high-silicon-resistant scale inhibitor for coal chemical wastewater and application of the reverse osmosis high-silicon-resistant scale inhibitor. The reverse osmosis high-silicon-resistant scale inhibitor for the coal chemical industry wastewater comprises an acrylic acid-sulfonate copolymer, 1, 2, 4-tricarboxylic acid-2-phosphonic acid butane, polyacrylic acid and hydrolytic polymaleic acid, and the weight ratio of the acrylic acid-sulfonate copolymer to the 1, 2, 4-tricarboxylic acid-2-phosphonic acid butane to the polyacrylic acid to the hydrolytic polymaleic acid is (15-25): (10-20): (2-8): (1-5).

Description

Technical Field

[0001] The present application belongs to the technical field of scale inhibitors, and specifically relates to a coal chemical wastewater reverse osmosis anti-high silicon scale inhibitor and its use. Background Art

[0002] Reverse osmosis technology has been widely used in the field of water purification and recycling. Reverse osmosis membrane technology generally requires the control of the content of substances that are prone to scaling in the reverse osmosis membrane inlet water to prevent scaling substances from precipitating on the membrane surface and blocking the membrane elements during the water concentration process, resulting in a decrease in the water production performance and water quality of the reverse osmosis membrane elements. Generally, the reverse osmosis inlet water is pretreated to reduce the content of scaling ions in the water and add scale inhibitors to prevent scaling and blocking of membrane elements. With the improvement of environmental protection requirements, most membrane chemical projects require zero discharge of wastewater, and wastewater needs to be fully recycled. Generally, membrane technology is used to concentrate and reduce the wastewater (preliminary concentration using brackish water membranes, and further concentration of brackish water membrane concentrate using seawater membranes). The highly concentrated wastewater is fully recovered by evaporation and crystallization technology, and the salt and other components in the water are precipitated in solid form.

[0003] Generally, conventional scaling ion concentrations such as calcium and magnesium can be initially removed by adding chemical agents and adopting precipitation methods. After highly concentrated, ion exchange methods are used to further remove calcium, magnesium and heavy metal ions. However, in the field of coal chemical industry, gasification and other devices react under high temperature and high pressure conditions. The wastewater produced during the reaction contains silicon, and the composition and type of silicon are relatively complex. There are soluble inorganic silicon, colloidal silicon, and organic silicon. Most of these silicons do not exist in the state of charged ions and are not easy to be removed. They exist in the water in a dissolved state. The content gradually increases during the concentration process. Sometimes the silicon content of seawater membrane reverse osmosis water can reach 40-50mg / L (or even higher). Because there is no efficient antiscalant for reverse osmosis membranes to prevent silicon scaling on the market, many coal chemical projects have silicon scaling in seawater reverse osmosis membranes and the subsequent evaporation crystallizers, which leads to reduced water production and poor thermal conductivity of evaporation crystallization heat exchangers. Summary of the invention

[0004] In view of the problems existing in the prior art, the present application provides a coal chemical wastewater reverse osmosis anti-high silicon scale inhibitor.

[0005] Specifically, this application involves the following aspects:

[0006] Item 1. A reverse osmosis anti-high-silicon scale inhibitor for coal chemical wastewater, which comprises acrylic acid-sulfonate copolymer, 1,2,4-tricarboxylic acid-2-phosphonic acid butane, polyacrylic acid and hydrolyzed polymaleic acid.

[0007] Item 2. The scale inhibitor according to Item 1, wherein, in the scale inhibitor, the weight ratio of the acrylic acid-sulfonate copolymer: 1,2,4-tricarboxylic acid-2-phosphonobutane: polyacrylic acid: hydrolyzed polymaleic acid is (15-25):(10-20):(2-8):(1-5).

[0008] Item 3. The scale inhibitor according to Item 2, wherein, in the scale inhibitor, the weight ratio of the acrylic acid-sulfonate copolymer: 1,2,4-tricarboxylic acid-2-phosphonobutane: polyacrylic acid: hydrolyzed polymaleic acid is (21-22): 15:5:3.

[0009] Item 4. The scale inhibitor according to Item 1, wherein, in the scale inhibitor, the concentration of the acrylic acid-sulfonate copolymer is 21-22% by weight, the concentration of the 1,2,4-tricarboxylic acid-2-phosphonobutane is 15% by weight, the concentration of the polyacrylic acid is 5% by weight, and the concentration of the hydrolyzed polymaleic acid is 3% by weight.

[0010] Item 5. The scale inhibitor according to Item 1, wherein the remainder is water.

[0011] Item 6. The scale inhibitor according to any one of Items 1 to 5, wherein the acrylic acid-sulfonate copolymer used to prepare the scale inhibitor is an acrylic acid-sulfonate copolymer aqueous solution, and the acrylic acid-sulfonate copolymer aqueous solution is an acrylic acid-sulfonate copolymer aqueous solution with a mass content of 35-50%, preferably 42-44%;

[0012] The 1,2,4-tricarboxylic acid-2-phosphonic acid butane used to prepare the scale inhibitor is a 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution, and the 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution is a 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution with a mass content of 40-60%, preferably 50%;

[0013] The polyacrylic acid used to prepare the scale inhibitor is a polyacrylic acid aqueous solution, and the polyacrylic acid aqueous solution is a polyacrylic acid aqueous solution with a mass content of 40-60%, preferably 50%;

[0014] The hydrolyzed polymaleic acid used to prepare the scale inhibitor is a hydrolyzed polymaleic acid aqueous solution, and the hydrolyzed polymaleic acid aqueous solution has a mass content of 20-40%, preferably 30%.

[0015] Item 7. Use of the scale inhibitor described in any one of Items 1 to 6 in coal chemical wastewater recovery.

[0016] Item 8. The use according to Item 7, wherein the scale inhibitor is used in reverse osmosis and evaporation crystallization processes in coal chemical wastewater recovery.

[0017] Item 9. The use according to Item 7, wherein the coal chemical wastewater is high silicon content wastewater.

[0018] Item 10. The use according to Item 9, wherein the high silicon content is 100 mg / mL or more, preferably 120 mg / mL or more, and more preferably 150-250 mg / mL.

[0019] Effects of the Invention

[0020] (1) The scale inhibitor of the present application can more effectively extend the cleaning cycle of the high-efficiency membrane system, better maintain the operating water output, reduce the number of chemical cleaning times of the membrane system, and reduce the workload of the operating personnel.

[0021] (2) The scale inhibitor of the present application can greatly improve the operating conditions of the evaporation crystallization heat exchanger, improve the operating stability and safety of the evaporation crystallization system, and reduce the labor intensity of employees in the evaporation crystallization system.

[0022] (3) The scale inhibitor of the present application can reduce the number of cleaning times of the high-efficiency membrane, significantly increase the service life of the reverse osmosis membrane of the high-efficiency membrane reverse osmosis system, and reduce the operating costs of the wastewater recovery device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a graph showing the change in water flow signal value over time of wastewater treated with imported antiscalant using comparative example 1 passing through three sets of high-efficiency membranes.

[0024] Figure 2 This is a graph showing the change in water flow signal value over time of wastewater treated with the scale inhibitor of Example 1 of the present application passing through three sets of high-efficiency membranes. DETAILED DESCRIPTION

[0025] The present application is further described below in conjunction with examples. It should be understood that the examples are only used to further describe and illustrate the present application and are not used to limit the present application.

[0026] Unless otherwise defined, the technical and scientific terms in this specification have the same meaning as those generally understood by those skilled in the art. Although similar or identical methods and materials as described herein may be used in experiments or practical applications, materials and methods are described herein below. In the event of a conflict, the present specification including the definitions therein shall prevail. In addition, materials, methods and examples are provided for illustration only and are not restrictive. The present application is further described below in conjunction with specific embodiments, but is not intended to limit the scope of the present application.

[0027] The silicon scale in coal chemical industry is mainly formed by the precipitation of organic silicon and colloidal silicon on the surface of high-salt water reverse osmosis membrane and the subsequent evaporation crystallizer after concentration, and gradually aggregates to form scale, and the scale is compacted and hardened under the compaction of water pressure, which is different from the chemical scaling mechanism of other cations and cations that form scale. In view of the characteristics of coal chemical wastewater with high pH value, high temperature, high silicon content and high salt content, this application adopts the compounding of scale inhibitor dispersant monomers with stable chemical properties at high pH value and high temperature and good dispersion performance of organic silicon and colloidal silicon, while taking into account the anti-scaling performance of preventing other scale-forming ions.

[0028] On the one hand, the present application provides a reverse osmosis high-silicon scale inhibitor for coal chemical wastewater, wherein it is composed of acrylic acid-sulfonate copolymer, 1,2,4-tricarboxylic acid-2-phosphonic acid butane, polyacrylic acid and hydrolyzed polymaleic acid. Among them, acrylic acid-sulfonate copolymer is a high-performance scale inhibitor dispersant, which can efficiently disperse the particles encountered, and is not affected by pH changes. It has a good dispersing effect on scale-forming salts such as calcium phosphate scale and calcium carbonate scale in water, inorganic minerals, and organic silicon particles. 1,2,4-tricarboxylic acid-2-phosphonic acid butane is a scale inhibitor and slow-release agent with excellent scale inhibition performance at high temperature, good chlorine oxidation resistance, good chelating performance, good compound synergy, and can be used in combination with copolymers. It can be used for high temperature, high hardness, high alkali and high salt content water quality. Polyacrylic acid is a dispersant with good performance under alkaline conditions. It can disperse microcrystals, colloids, silt, and organic silicon particles of salts such as calcium carbonate and calcium sulfate in water without precipitation, thereby achieving the purpose of dispersion and scale inhibition. Hydrolyzed polymaleic acid is a highly efficient dispersant with good dispersibility for colloids, organic particles and silica in water under alkaline conditions.

[0029] The present application successfully prepares a scale inhibitor for treating high-silicon coal chemical wastewater by utilizing the synergistic effect of acrylic acid-sulfonate copolymer, 1,2,4-tricarboxylic acid-2-phosphonobutane, polyacrylic acid and hydrolyzed polymaleic acid.

[0030] In the above-mentioned scale inhibitor, as a preferred embodiment, the weight ratio of the acrylic acid-sulfonate copolymer: 1,2,4-tricarboxylic acid-2-phosphonobutane: polyacrylic acid: hydrolyzed polymaleic acid is (15-25):(10-20):(2-8):(1-5).

[0031] In the above-mentioned scale inhibitor, as a preferred embodiment, the weight ratio of the acrylic acid-sulfonate copolymer: 1,2,4-tricarboxylic acid-2-phosphonobutane: polyacrylic acid: hydrolyzed polymaleic acid is (21-22): 15:5:3.

[0032] In the above-mentioned scale inhibitor, as a preferred embodiment, in the scale inhibitor, the concentration of the acrylic acid-sulfonate copolymer is 21-22% by weight, the concentration of the 1,2,4-tricarboxylic acid-2-phosphonic acid butane is 15% by weight, the concentration of the polyacrylic acid is 5% by weight, and the concentration of the hydrolyzed polymaleic acid is 3% by weight.

[0033] In the above-mentioned antiscalant, as a preferred embodiment, the balance is water.

[0034] In the above-mentioned scale inhibitor, as a preferred embodiment, the acrylic acid-sulfonate copolymer used to prepare the scale inhibitor is an acrylic acid-sulfonate copolymer aqueous solution, and the acrylic acid-sulfonate copolymer aqueous solution is an acrylic acid-sulfonate copolymer aqueous solution with a mass content of 35-50%, preferably 42-44%;

[0035] The 1,2,4-tricarboxylic acid-2-phosphonic acid butane used to prepare the scale inhibitor is a 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution, and the 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution is a 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution with a mass content of 40-60%, preferably 50%;

[0036] The polyacrylic acid used to prepare the scale inhibitor is a polyacrylic acid aqueous solution, and the polyacrylic acid aqueous solution is a polyacrylic acid aqueous solution with a mass content of 40-60%, preferably 50%;

[0037] The hydrolyzed polymaleic acid used to prepare the scale inhibitor is a hydrolyzed polymaleic acid aqueous solution, and the hydrolyzed polymaleic acid aqueous solution has a mass content of 20-40%, preferably 30%.

[0038] On the other hand, the present application provides a use of the above-mentioned scale inhibitor in coal chemical wastewater recovery.

[0039] Among the above uses, as a preferred embodiment, the scale inhibitor is used in the reverse osmosis and evaporation crystallization process in coal chemical wastewater recovery.

[0040] In the above-mentioned use, as a preferred embodiment, the scale inhibitor and the coal chemical wastewater are high-silicon content wastewater.

[0041] In the above-mentioned use, as a preferred embodiment, the high silicon content is 100 mg / mL or more, preferably 120 mg / mL or more, and more preferably 150-250 mg / mL.

[0042] In September 2019, a coal chemical company in Xinjiang carried out a major overhaul of the equipment. After the overhaul, the water inlet of the water treatment system of the public works production center changed significantly compared with before the overhaul, and brought many adverse effects to the operation of the system. For the high-efficiency membrane reverse osmosis system and the evaporation crystallization system, it is specifically manifested in: the high-efficiency membrane reverse osmosis is seriously blocked, the water production volume decays rapidly after the membrane is cleaned, and the cleaning cycle is very short; the heat exchanger scales quickly before evaporation and crystallization, the operating flux drops rapidly, and the heat exchange effect deteriorates rapidly. Among them, the high-efficiency membrane concentration device adopts HERO high-efficiency reverse osmosis technology, and adopts a combination of chemical precipitation, ion exchange, and membrane concentration to improve the system recovery rate. The scale of each set of high-efficiency membrane is 150m3 of water inlet. 3 / h seawater reverse osmosis device, 2 in use and 1 as standby, that is, there are 3 sets of high-efficiency membranes, 2 of which are in use and 1 is in standby (all 3 sets of high-efficiency membrane devices are in use), and the water inflow of the high-efficiency membrane is 300m 3 / h, the amount of scale inhibitor added is 3-5g / m 3 (Additives are added continuously as water continues to flow in).

[0043] In order to solve or alleviate the above problems, the inventors of this application took water samples and scale samples for detailed analysis, and formulated a scale inhibitor and dispersant suitable for the actual water quality of this project according to the water quality. They also tried it on this project to verify the actual effect of the agent.

[0044] Comparative Example 1

[0045] In this comparative example, the anti-high silicon scale inhibitor is the original commercially available model 710A (imported scale inhibitor brand). The scale inhibitor was used in the above project, and the scale inhibitor test time was 25 days. The scale inhibitor was added to the water inlet pipe of the high-efficiency reverse osmosis device, and the scale inhibitor dosage was 5 mg / l water, that is, 1.5 kg / h.

[0046] Before adding the scale inhibitor, the silicon content in the wastewater was 116 mg / ml. After adding the scale inhibitor and reacting, the silicon content in the wastewater was 110 mg / ml. After the scale inhibitor treatment, the wastewater flows through the high-efficiency membrane for concentration.

[0047] During the use of this antiscalant, see the attached Figure 1 ,It can be seen that the equipment is shut down many times and the ,operation time is short, which means that the high-efficiency membrane is ,cleaned frequently and the operation cycle is short.

[0048] According to statistics, during the period of using the scale inhibitor, the three sets of high-efficiency membranes underwent a total of 69 chemical cleanings. Basically, each set of the three high-efficiency membranes had to be cleaned once a day, sometimes even twice or more. After cleaning, the water production of the second stage decayed very quickly, and some even had an operating cycle of less than 3 hours.

[0049] On the other hand, during the use of the scale inhibitor, the water flow rate fluctuated greatly during the evaporation and crystallization of the plate heat exchanger, the operation was unstable, the flow rate dropped rapidly, and the flow rate could only be within 40m most of the time. 3 / h nearby.

[0050] Comparative Example 2

[0051] In this comparative example, 30 parts by weight of an acrylic acid-sulfonate copolymer aqueous solution (the acrylic acid-sulfonate copolymer content in the aqueous solution is 42-44%), 20 parts by weight of a 1,2,4-tricarboxylic acid-2-phosphonobutane aqueous solution (the 1,2,4-tricarboxylic acid-2-phosphonobutane aqueous solution has a 1,2,4-tricarboxylic acid-2-phosphonobutane content of 50%), 10 parts by weight of polyacrylic acid, 10 parts by weight of hydrolyzed polymaleic acid (the hydrolyzed polymaleic acid content in the hydrolyzed polymaleic acid aqueous solution is 50%), 10 parts by weight of an acrylic acid-acrylate-sulfonate terpolymer aqueous solution (the acrylic acid-acrylate-sulfonate terpolymer content in the acrylic acid-acrylate-sulfonate terpolymer aqueous solution is 30%) and 20 parts by weight of water are weighed to prepare a scale inhibitor.

[0052] The scale inhibitor was used in the above project, and the scale inhibitor test time was 25 days.

[0053] The dosing position and dosage of the scale inhibitor are the same as those in Comparative Example 1.

[0054] Before adding the scale inhibitor, the silicon content in the wastewater was 109 mg / ml. After adding the scale inhibitor and reacting, the silicon content in the wastewater was about 100 mg / ml. After the scale inhibitor treatment, the wastewater flows through the high-efficiency membrane for concentration.

[0055] During the period when the antiscalant was used, the equipment operating time was extremely short and the concentrated water reverse osmosis had difficulty operating normally.

[0056] According to statistics, during the period of using this scale inhibitor, the three sets of high-efficiency membranes underwent a total of 98 chemical cleanings. Basically, each set of high-efficiency membranes had to be cleaned at least twice a day. The water production declined very quickly after cleaning, and the operating cycle was only about 10 hours.

[0057] On the other hand, during the use of the scale inhibitor, the plate heat exchanger was unstable during evaporation and crystallization, and the flow rate dropped rapidly. The flow rate could only be around 35m / s for a period of time. 3 / h nearby.

[0058] Example 1

[0059] In this embodiment, 50 parts by weight of acrylic acid-sulfonate copolymer aqueous solution (the mass content of acrylic acid-sulfonate copolymer (phosphorus-free) in the aqueous solution is 42-44%), 30 parts by weight of 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution (the mass content of 1,2,4-tricarboxylic acid-2-phosphonic acid butane in the 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution is 50%), 10 parts by weight of polyacrylic acid aqueous solution (the mass content of polyacrylic acid in the polyacrylic acid aqueous solution is 50%) and 10 parts by weight of hydrolyzed polymaleic acid aqueous solution (the mass content of hydrolyzed polymaleic acid (phosphorus-free) in the hydrolyzed polymaleic acid aqueous solution is 30%) are weighed to prepare the scale inhibitor. The scale inhibitor is used in the above project, and the scale inhibitor test time is 25 days.

[0060] The dosing position and dosage of the scale inhibitor are the same as those in Comparative Example 1.

[0061] Before adding the scale inhibitor, the silicon content in the wastewater was 123 mg / ml. After adding the scale inhibitor and reacting, the silicon content in the wastewater was below 100 mg / ml. After the scale inhibitor treatment, the wastewater flows through the high-efficiency membrane for concentration. During the use of the scale inhibitor, see the attached Figure 2 , we can see that: Figure 1 and Figure 2 compared to, Figure 1 Compare Figure 2 The fluctuation curves are obviously dense, and the interval between the curves is short, which shows that the equipment using the scale inhibitor of this embodiment ( Figure 2 ) The number of shutdowns is higher than that of the scale inhibitor in comparative example 1 ( Figure 1 ) has fewer equipment shutdowns and a longer operating time than the operating cycle of the scale inhibitor used in Comparative Example 1.

[0062] According to statistics, during the use of the scale inhibitor, the three sets of high-efficiency membranes were chemically cleaned 42 times in total, basically only one set was cleaned every day, and at most two sets were cleaned. In addition, the second stage water flow rate decayed slowly, and sometimes cleaning was performed in advance to ensure the water production. It can be seen that compared with the scale inhibitor used in the above-mentioned comparative example 1, the number of cleaning times using the anti-high silicon scale inhibitor of this embodiment was reduced by 39%. The reduction in the number of cleaning times after using the anti-high silicon scale inhibitor of this embodiment directly shows that the anti-high silicon scale inhibitor of this embodiment can significantly extend the chemical cleaning cycle of the high-efficiency membrane.

[0063] In addition, the water production of the high-efficiency membrane is significantly improved compared with the case where the scale inhibitor of Comparative Example 1 is used, and the water production decays more slowly.

[0064] On the other hand, during the use of the scale inhibitor, when the plate heat exchanger evaporates and crystallizes, the water flow rate of the plate heat exchanger is stable and decreases slowly, and the flow rate is basically maintained at 45m 3 / h or more.

[0065] Example 2

[0066] In this embodiment, 45 parts by weight of an aqueous solution of acrylic acid-sulfonate copolymer (the mass content of acrylic acid-sulfonate copolymer (phosphorus-free) in the aqueous solution is 42-44%), 33 parts by weight of an aqueous solution of 1,2,4-tricarboxylic acid-2-phosphonic acid butane (the mass content of 1,2,4-tricarboxylic acid-2-phosphonic acid butane in the aqueous solution is 50%), 12 parts by weight of an aqueous solution of polyacrylic acid (the mass content of polyacrylic acid in the aqueous solution is 50%), and 10 parts by weight of an aqueous solution of hydrolyzed polymaleic acid (the mass content of hydrolyzed polymaleic acid (phosphorus-free) in the aqueous solution is 30%) are weighed to prepare a scale inhibitor, and the scale inhibitor is used in the above-mentioned project, and the scale inhibitor test time is 25 days.

[0067] The dosing position and dosage of the scale inhibitor are the same as those of Comparative Example 1 and Example 1.

[0068] Before adding the scale inhibitor, the silicon content in the wastewater was 110 mg / ml. After adding the scale inhibitor and reacting, the silicon content in the wastewater was maintained at 100 mg / ml. After the scale inhibitor treatment, the wastewater flows through the high-efficiency membrane for concentration.

[0069] During the use of the antiscalant, the equipment is shut down less frequently than when the antiscalant of Comparative Examples 1 and 2 is used, the operation time is longer than when the antiscalant of Comparative Examples 1 and 2 is used, and the operation cycle is longer.

[0070] According to statistics, during the use of the scale inhibitor, three sets of high-efficiency membranes were chemically cleaned 55 times in total, and the concentrated water reverse osmosis operation cycle reached more than 20 hours, which basically ensured the operation of the concentrated water reverse osmosis membrane. It can be seen that compared with the scale inhibitor used in the above-mentioned comparative example 1, the number of cleaning times using the high-silicon scale inhibitor of this embodiment was reduced by 20%. Compared with the scale inhibitor used in the above-mentioned comparative example 2, the number of cleaning times using the anti-high-silicon scale inhibitor of this embodiment was greatly reduced. The reduction in the number of cleaning times after using the anti-high-silicon scale inhibitor of this embodiment directly shows that the anti-high-silicon scale inhibitor of this embodiment can significantly extend the chemical cleaning cycle of the high-efficiency membrane.

[0071] In addition, the water production of the high-efficiency membrane is significantly improved compared with the scale inhibitor of the comparative example 2, and the water production decays more slowly, and the operation cycle is doubled.

[0072] On the other hand, during the use of the scale inhibitor, when the plate heat exchanger evaporates and crystallizes, the water flow rate of the plate heat exchanger is stable and decreases slowly, and the flow rate is basically maintained at 43m 3 / h or more.

[0073] Table 1

[0074]

[0075]

Claims

1. A coal chemical wastewater reverse osmosis anti-high silicon scale inhibitor, wherein: It includes acrylic acid-sulfonate copolymer, 1,2,4-tricarboxylic acid-2-phosphonobutane, polyacrylic acid and hydrolyzed polymaleic acid.

2. The scale inhibitor according to claim 1, wherein In the scale inhibitor, the weight ratio of the acrylic acid-sulfonate copolymer: 1,2,4-tricarboxylic acid-2-phosphonobutane: polyacrylic acid: hydrolyzed polymaleic acid is (15-25):(10-20):(2-8):(1-5).

3. The scale inhibitor according to claim 2, wherein: In the scale inhibitor, the weight ratio of the acrylic acid-sulfonate copolymer: 1,2,4-tricarboxylic acid-2-phosphonobutane: polyacrylic acid: hydrolyzed polymaleic acid is (21-22): 15:5:

3.

4. The scale inhibitor according to claim 1, wherein In the scale inhibitor, the concentration of the acrylic acid-sulfonate copolymer is 21-22% by weight, the concentration of the 1,2,4-tricarboxylic acid-2-phosphonobutane is 15% by weight, the concentration of the polyacrylic acid is 5% by weight, and the concentration of the hydrolyzed polymaleic acid is 3% by weight.

5. The scale inhibitor according to claim 1, wherein: The balance is water.

6. The scale inhibitor according to any one of claims 1 to 5, wherein: The acrylic acid-sulfonate copolymer used to prepare the scale inhibitor is an acrylic acid-sulfonate copolymer aqueous solution, wherein the acrylic acid-sulfonate copolymer aqueous solution is an acrylic acid-sulfonate copolymer aqueous solution with a mass content of 35-50%, preferably 42-44%; The 1,2,4-tricarboxylic acid-2-phosphonic acid butane used to prepare the scale inhibitor is a 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution, and the 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution is a 1,2,4-tricarboxylic acid-2-phosphonic acid butane aqueous solution with a mass content of 40-60%, preferably 50%; The polyacrylic acid used to prepare the scale inhibitor is a polyacrylic acid aqueous solution, and the polyacrylic acid aqueous solution is a polyacrylic acid aqueous solution with a mass content of 40-60%, preferably 50%; The hydrolyzed polymaleic acid used to prepare the scale inhibitor is a hydrolyzed polymaleic acid aqueous solution, and the hydrolyzed polymaleic acid aqueous solution has a mass content of 20-40%, preferably 30%.

7. Use of the scale inhibitor according to any one of claims 1 to 6 in coal chemical wastewater recovery.

8. The use according to claim 7, wherein The scale inhibitor is used in the reverse osmosis and evaporation crystallization process in coal chemical wastewater recovery.

9. The use according to claim 7, wherein: The coal chemical wastewater is high-silicon content wastewater.

10. The use according to claim 9, wherein The high silicon content is 100 mg / mL or more, preferably 120 mg / mL or more, and more preferably 150-250 mg / mL.

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