Phosphorus-free scale inhibiting dispersant and method for preparing the same

Abstract

The application discloses a kind of phosphorus-free scale inhibiting dispersants and preparation method thereof.In one aspect, the application provides a kind of phosphorus-free scale inhibiting dispersants, and the mass fraction ratio of each component of the phosphorus-free scale inhibiting dispersants includes: modified polyaspartic acid-acrylic acid-EDTA copolymer 24~28 parts, itaconic acid-styrene sulfonic acid copolymer 60~64 parts, zinc sulfate 2~3 parts.In another aspect, the application provides the preparation method of the above-mentioned phosphorus-free scale inhibiting dispersant, including the following steps: S1, preparation modified polyaspartic acid-acrylic acid-EDTA copolymer;S2, preparation itaconic acid-styrene sulfonic acid copolymer;S3, according to formula amount weighing each component, after being mixed sufficiently, phosphorus-free scale inhibiting dispersant is prepared.The high temperature stability of the application is better, and the scale inhibiting effect of calcium, magnesium, barium and other ions is all more excellent.

Description

Technical Field

[0001] This application relates to the field of coal gasification ash water treatment technology, and in particular to a phosphorus-free scale inhibitor and dispersant and its preparation method. Background Technology

[0002] Coal gasification is a chemical technology that converts coal into combustible gases such as carbon monoxide and hydrogen through high-temperature reactions. It can produce products such as syngas and industrial fuel gas, and is applied in fields such as power generation, synthetic ammonia, and methanol production.

[0003] In coal gasification processes, ash water treatment is one of the core technologies, directly determining whether the process unit can operate stably for a long period. Because coal contains impurities such as calcium and magnesium, and the temperature of ash water in coal gasification processes is generally above 200℃, coal gasification ash water typically exhibits characteristics such as high temperature, high pressure, high turbidity, high hardness, and high alkalinity. During its circulation, it is prone to adverse phenomena such as deposition, scaling, and corrosion, affecting the normal and stable operation of the coal gasification equipment.

[0004] Currently, the solution to the above problems is to add scale inhibitors and dispersants to prevent scaling ions from forming inside the equipment. Considering the characteristics of coal gasification ash water, high-temperature resistant scale inhibitors and dispersants are needed to ensure the continued effectiveness of coal gasification ash water treatment. Existing high-temperature resistant scale inhibitors and dispersants mainly include organophosphorus compounds, polycarboxylic acid compounds (such as polyacrylic acid compounds), sulfonic acid compounds, and complexes. Among them, organophosphorus scale inhibitors and dispersants can lead to subsequent environmental pollution, while polycarboxylic acid and sulfonic acid scale inhibitors and dispersants have relatively excellent anti-scale effects, but their scale inhibition rates are still insufficient. Composite scale inhibitors and dispersants, which combine the advantages of various scale inhibitors and dispersants, are currently a research hotspot.

[0005] However, while existing composite scale inhibitors and dispersants have a superior scale inhibition effect on calcium ions, their scale inhibition effect on other ions is still somewhat insufficient. Summary of the Invention

[0006] In order to solve at least one of the above-mentioned technical problems, and to develop a composite scale inhibitor and dispersant with good high-temperature stability and excellent scale inhibition effect against calcium, magnesium, barium and other ions, this application provides a phosphorus-free scale inhibitor and dispersant and its preparation method.

[0007] On the one hand, this application provides a phosphorus-free scale inhibitor and dispersant, wherein the mass ratio of each component of the phosphorus-free scale inhibitor and dispersant includes: 24-28 parts of modified polyaspartic acid-acrylic acid-EDTA copolymer, 60-64 parts of itaconic acid-styrene sulfonic acid copolymer, and 2-3 parts of zinc sulfate.

[0008] Optionally, the raw material components of the toughened and wear-resistant polyester fiber are proportioned as follows: 100 parts PET resin, 8-10 parts modified nano carbon fiber, 4-5 parts nano titanium dioxide, 14-16 parts maleic anhydride grafted polyolefin elastomer, 20-22 parts modified magnesium hydroxide, 8-10 parts coated ammonium polyphosphate, 5-6 parts hydroxylated carbon nanotubes, and 0.3-0.5 parts composite antioxidant.

[0009] Optionally, the preparation of the modified polyaspartic acid-acrylic acid-EDTA copolymer includes the following steps: S1-1. Weigh maleic anhydride and acrylic acid in a molar ratio of 1:1.4~1.5, add water to prepare a solution, add an initiator and ammonia water with a molar amount of 1.2~1.4 times that of maleic anhydride, react at 180~185℃ for 1~1.5h, cool and add sodium hydroxide to hydrolyze to obtain polyaspartic acid-acrylic acid copolymer. S1-2. Weigh polyaspartic acid-acrylic acid copolymer and EDTA at a molar ratio of 1:0.4~0.5, add water to prepare a solution, add a catalyst, react at 75~80℃ for 2 hours, and after cooling, obtain polyaspartic acid-acrylic acid-EDTA copolymer.

[0010] Further optionally, in step S1-1, the molar ratio of maleic anhydride to acrylic acid is 1:1.42~1.45.

[0011] Optionally, in step S1-1, the molar ratio of maleic anhydride to ammonia is 1:1.22~1.25.

[0012] Optionally, in step S1-1, the initiator is ammonium persulfate, and the amount of initiator added accounts for 1.8-2% of the total mass of maleic anhydride and acrylic acid.

[0013] Further optionally, in steps S1-2, the molar ratio of polyaspartic acid-acrylic acid copolymer to EDTA is 1:0.46~0.48.

[0014] Optionally, in steps S1-2, the catalyst is 1-hydroxybenzotriazine, and the amount of catalyst added accounts for 5.6-5.8% of the total mass of polyaspartic acid-acrylic acid copolymer and EDTA.

[0015] Optionally, the preparation of the itaconic acid-styrene sulfonic acid copolymer includes the following steps: S2-1. Weigh itaconic acid and styrene sulfonic acid precisely according to a molar ratio of 2.2~2.4:1, add water, and heat to 70~75℃ to prepare a solution; S2-2. Add an initiator to the solution, then heat to 100~105℃, maintain the temperature for 1.8~2h, and after cooling, obtain itaconic acid-styrene sulfonic acid copolymer.

[0016] Optionally, in step S2-2, the initiator is ammonium persulfate, and the amount of initiator added accounts for 6.2-6.5% of the total mass of itaconic acid and styrene sulfonic acid.

[0017] On the other hand, this application provides a method for preparing the above-mentioned phosphorus-free scale inhibitor and dispersant, comprising the following steps: S1. Preparation of modified polyaspartic acid-acrylic acid-EDTA copolymer; S2. Preparation of itaconic acid-styrene sulfonic acid copolymer; S3. Weigh each component according to the formula, mix them thoroughly, and then prepare a phosphorus-free scale inhibitor and dispersant.

[0018] In summary, the present invention has at least one of the following beneficial technical effects: 1. This application uses a specific modified polyaspartic acid-acrylic acid-EDTA copolymer and itaconic acid-styrene sulfonic acid copolymer to prepare a composite scale inhibitor and dispersant. It has excellent chelating properties for a variety of scale ions and strong stability at high temperatures. It can have a strong scale inhibition rate for scale ions such as calcium, magnesium, and barium.

[0019] 2. Zinc sulfate was added to this application, which gave the system excellent corrosion inhibition performance. The modified polyaspartic acid-acrylic acid-EDTA copolymer and itaconic acid-styrene sulfonic acid copolymer have a synergistic effect. At a high temperature of 250℃, the scale inhibition rate of calcium, magnesium, barium, iron and other scaling ions all exceeded 80%. Detailed Implementation

[0020] The present application will be further described in detail below with reference to the embodiments.

[0021] Unless otherwise stated, the raw materials used in this application are conventional materials in this technical field and are all commercially available. Unless otherwise specified, the test methods and detection methods in the following embodiments are conventional methods, and the equipment and instruments used in the tests are all commercially available. Parts not described in detail in this specification belong to the prior art.

[0022] This application provides a phosphorus-free scale inhibitor and dispersant, wherein the mass ratio of each component of the phosphorus-free scale inhibitor and dispersant includes: 24-28 parts of modified polyaspartic acid-acrylic acid-EDTA copolymer, 60-64 parts of itaconic acid-styrene sulfonic acid copolymer, and 2-3 parts of zinc sulfate.

[0023] The preparation method of the above-mentioned phosphorus-free scale inhibitor includes the following steps: S1. Preparation of modified polyaspartic acid-acrylic acid-EDTA copolymer; S2. Preparation of itaconic acid-styrene sulfonic acid copolymer; S3. Weigh each component according to the formula, mix them thoroughly, and then prepare a phosphorus-free scale inhibitor and dispersant.

[0024] In existing technologies, sulfonic acid scale inhibitors are the preferred high-temperature resistant, phosphorus-free scale inhibitors and dispersants. These inhibitors exhibit stable high-temperature performance and excellent scale inhibition effect against calcium ions. Therefore, existing composite scale inhibitors and dispersants typically combine sulfonic acid scale inhibitors with polycarboxylic acid scale inhibitors to achieve better scale inhibition results. However, when different types of scale inhibitors are mixed, mutual interference between the functional groups can easily occur, resulting in limited improvement in scale inhibition performance. Furthermore, existing scale inhibitors and dispersants usually use calcium and magnesium ions as design and research indicators, and their scale inhibition effect on other scaling ions is generally insufficient.

[0025] This application, through reasonable design, combines modified polyaspartic acid-acrylic acid-EDTA copolymer and itaconic acid-styrene sulfonic acid copolymer in a specific ratio to prepare a composite scale inhibitor and dispersant. There is no mutual interference between the two groups, and they can form a synergistic chelating effect. The chelating effect on scale ions such as calcium, magnesium, barium, and iron is excellent, and the overall performance is good.

[0026] The following are preparation examples and embodiments of this application.

[0027] The main raw materials used in the embodiments of this application are all commercially available.

[0028] Among them, maleic anhydride, with a purity of over 99%, was purchased from Shanghai Aladdin; acrylic acid, with a purity of over 99%, was purchased from Shanghai Aladdin; EDTA, with a purity of over 99.5%, was purchased from Shanghai Aladdin; itaconic acid, with a purity of over 99.5%, was purchased from Shandong Feiyang Chemical Co., Ltd.; and styrene sulfonic acid, with a purity of over 99%, was purchased from Shandong Guohua Chemical Co., Ltd.

[0029] The following is a preparation example of this application.

[0030] Preparation Example 1 The preparation of the modified polyaspartic acid-acrylic acid-EDTA copolymer in this example includes the following steps: S1-1. Weigh maleic anhydride and acrylic acid in a molar ratio of 1:1.4, add water to prepare a solution, add ammonium persulfate (1.5% of the total mass of maleic anhydride and acrylic acid) and ammonia water (1.2 times the molar mass of maleic anhydride), react at 180~185℃ for 1 hour, cool, add sodium hydroxide to hydrolyze, filter, wash and dry to obtain polyaspartic acid-acrylic acid copolymer; S1-2. Weigh polyaspartic acid-acrylic acid copolymer and EDTA at a molar ratio of 1:0.4, add water to prepare a solution, add 5% of 1-hydroxybenzotriazine by mass of polyaspartic acid-acrylic acid copolymer and EDTA, react at 75~80℃ for 2 hours, cool, filter, wash and dry to obtain polyaspartic acid-acrylic acid-EDTA copolymer.

[0031] Preparation Example 2 The preparation of the modified polyaspartic acid-acrylic acid-EDTA copolymer in this example includes the following steps: S1-1. Weigh maleic anhydride and acrylic acid in a molar ratio of 1:1.5, add water to prepare a solution, add ammonium persulfate (1.5% of the total mass of maleic anhydride and acrylic acid) and ammonia water (1.4 times the molar mass of maleic anhydride), react at 180~185℃ for 1 hour, cool, add sodium hydroxide to hydrolyze, filter, wash and dry to obtain polyaspartic acid-acrylic acid copolymer; S1-2. Weigh polyaspartic acid-acrylic acid copolymer and EDTA at a molar ratio of 1:0.5, add water to prepare a solution, add 5% of 1-hydroxybenzotriazine by mass of polyaspartic acid-acrylic acid copolymer and EDTA, react at 75~80℃ for 2 hours, cool, filter, wash and dry to obtain polyaspartic acid-acrylic acid-EDTA copolymer.

[0032] Preparation Example 3 The preparation of the modified polyaspartic acid-acrylic acid-EDTA copolymer in this example includes the following steps: S1-1. Weigh maleic anhydride and acrylic acid in a molar ratio of 1:1.42, add water to prepare a solution, add ammonium persulfate (1.8% of the total mass of maleic anhydride and acrylic acid) and ammonia water (1.22 times the molar mass of maleic anhydride), react at 180~185℃ for 1 hour, cool, add sodium hydroxide to hydrolyze, filter, wash and dry to obtain polyaspartic acid-acrylic acid copolymer; S1-2. Weigh polyaspartic acid-acrylic acid copolymer and EDTA at a molar ratio of 1:0.46, add water to prepare a solution, add 5.6% of 1-hydroxybenzotriazine by mass of polyaspartic acid-acrylic acid copolymer and EDTA, react at 75~80℃ for 2 hours, cool, filter, wash and dry to obtain polyaspartic acid-acrylic acid-EDTA copolymer.

[0033] Preparation Example 4 The preparation of the modified polyaspartic acid-acrylic acid-EDTA copolymer in this example includes the following steps: S1-1. Weigh maleic anhydride and acrylic acid in a molar ratio of 1:1.45, add water to prepare a solution, add ammonium persulfate (2% of the total mass of maleic anhydride and acrylic acid) and ammonia water (1.25 times the molar mass of maleic anhydride), react at 180~185℃ for 1 hour, cool, add sodium hydroxide to hydrolyze, filter, wash and dry to obtain polyaspartic acid-acrylic acid copolymer; S1-2. Weigh polyaspartic acid-acrylic acid copolymer and EDTA at a molar ratio of 1:0.48, add water to prepare a solution, add 5.8% of 1-hydroxybenzotriazine by mass of polyaspartic acid-acrylic acid copolymer and EDTA, react at 75~80℃ for 2 hours, cool, filter, wash and dry to obtain polyaspartic acid-acrylic acid-EDTA copolymer.

[0034] Preparation Example 5 The preparation of the itaconic acid-styrene sulfonic acid copolymer in this example includes the following steps: S2-1. Weigh itaconic acid and styrene sulfonic acid precisely according to a molar ratio of 2.2:1, add water, and heat to 70~75℃ to prepare a solution. S2-2. Add ammonium persulfate at 6% of the total mass of itaconic acid and styrene sulfonic acid to the solution, then heat to 100~105℃ and keep the reaction at this temperature for 1.8h. After cooling, filter, wash and dry to obtain itaconic acid-styrene sulfonic acid copolymer.

[0035] Preparation Example 6 The preparation of the itaconic acid-styrene sulfonic acid copolymer in this example includes the following steps: S2-1. Weigh itaconic acid and styrene sulfonic acid precisely according to a molar ratio of 2.4:1, add water, and heat to 70~75℃ to prepare a solution. S2-2. Add ammonium persulfate at a mass of 6.5% of the total mass of itaconic acid and styrene sulfonic acid to the solution, then heat to 100~105℃ and keep the reaction at this temperature for 2 hours. After cooling, filter, wash and dry to obtain itaconic acid-styrene sulfonic acid copolymer.

[0036] Preparation Example 7 The preparation of the itaconic acid-styrene sulfonic acid copolymer in this example includes the following steps: S2-1. Weigh itaconic acid and styrene sulfonic acid precisely according to a molar ratio of 2.32:1, add water, and heat to 70~75℃ to prepare a solution. S2-2. Add ammonium persulfate at a mass of 6.2% of the total mass of itaconic acid and styrene sulfonic acid to the solution, then heat to 100~105℃ and keep the reaction at this temperature for 2 hours. After cooling, filter, wash and dry to obtain itaconic acid-styrene sulfonic acid copolymer.

[0037] The following are embodiments of this application.

[0038] The preparation method of the phosphorus-free scale inhibitor and dispersant in this application includes the following steps: S1. Select modified polyaspartic acid-acrylic acid-EDTA copolymer; S2. Select itaconic acid-styrene sulfonic acid copolymer; S3. Weigh each component according to the formula, mix them thoroughly, and then prepare a phosphorus-free scale inhibitor and dispersant.

[0039] Example 1 The mass ratio of each component in the phosphorus-free scale inhibitor and dispersant of this embodiment includes: 24 parts of modified polyaspartic acid-acrylic acid-EDTA copolymer, 60 parts of itaconic acid-styrene sulfonic acid copolymer, and 2 parts of zinc sulfate.

[0040] In this embodiment, the modified polyaspartic acid-acrylic acid-EDTA copolymer of Preparation Example 1 and the itaconic acid-styrene sulfonic acid copolymer of Preparation Example 5 were selected.

[0041] Example 2 The mass ratio of each component in the phosphorus-free scale inhibitor and dispersant of this embodiment includes: 28 parts of modified polyaspartic acid-acrylic acid-EDTA copolymer, 64 parts of itaconic acid-styrene sulfonic acid copolymer, and 3 parts of zinc sulfate.

[0042] In this embodiment, the modified polyaspartic acid-acrylic acid-EDTA copolymer of Preparation Example 1 and the itaconic acid-styrene sulfonic acid copolymer of Preparation Example 5 were selected.

[0043] Example 3 The mass ratio of each component in the phosphorus-free scale inhibitor and dispersant of this embodiment includes: 26 parts of modified polyaspartic acid-acrylic acid-EDTA copolymer, 62 parts of itaconic acid-styrene sulfonic acid copolymer, and 2.8 parts of zinc sulfate.

[0044] In this embodiment, the modified polyaspartic acid-acrylic acid-EDTA copolymer of Preparation Example 1 and the itaconic acid-styrene sulfonic acid copolymer of Preparation Example 5 were selected.

[0045] Example 4 The difference between this embodiment and Example 3 is that this embodiment selects the modified polyaspartic acid-acrylic acid-EDTA copolymer of Preparation Example 2 and the itaconic acid-styrene sulfonic acid copolymer of Preparation Example 6.

[0046] Example 5 The difference between this embodiment and Example 3 is that this embodiment selects the modified polyaspartic acid-acrylic acid-EDTA copolymer of Example 3 and the itaconic acid-styrene sulfonic acid copolymer of Example 7.

[0047] Example 6 The difference between this embodiment and Example 3 is that this embodiment selects the modified polyaspartic acid-acrylic acid-EDTA copolymer of Preparation Example 4 and the itaconic acid-styrene sulfonic acid copolymer of Preparation Example 7.

[0048] Comparative Example 1 This application uses the Aike AK-610 grey water scale inhibitor and dispersant sold by Beijing Sanshidaxin Technology Co., Ltd. as comparative example 1. This scale inhibitor and dispersant is a compound of organic phosphonic acid scale inhibitor and sulfonic acid scale inhibitor.

[0049] Comparative Example 2 The difference between this comparative example and Example 6 is that an equal amount of modified polyaspartic acid-acrylic acid-EDTA copolymer was used instead of itaconic acid-styrene sulfonic acid copolymer.

[0050] Comparative Example 3 The difference between this comparative example and Example 6 is that an equal amount of itaconic acid-styrene sulfonic acid copolymer was used to replace the modified polyaspartic acid-acrylic acid-EDTA copolymer.

[0051] Comparative Example 4 The difference between this comparative example and Example 6 is that the monomer molar ratio of the modified polyaspartic acid-acrylic acid-EDTA copolymer is 1:2:0.6.

[0052] Comparative Example 5 The difference between this comparative example and Example 6 is that the monomer molar ratio of the modified polyaspartic acid-acrylic acid-EDTA copolymer is 1:1.2:0.35.

[0053] Comparative Example 6 The difference between this comparative example and Example 6 is that the molar ratio of the monomers in the itaconic acid-styrene sulfonic acid copolymer is 2:1 (itaconic acid:styrene sulfonic acid).

[0054] Comparative Example 7 The difference between this comparative example and Example 6 is that the molar ratio of the monomers in the itaconic acid-styrene sulfonic acid copolymer is 3:1 (itaconic acid:styrene sulfonic acid).

[0055] The performance of the products from Examples 1-6 and Comparative Examples 1-7 was tested. The scale inhibitors and dispersants from Examples 1-6 and Comparative Examples 1-7 were all added at a dosage of 40 mg / L to a coal gasification process ash water sample (taken from a coal gasification process equipment in a coal chemical plant). The ash water sample was then heated to 250℃ and held for 30 min, followed by cooling to room temperature. The ion concentrations before and after the tests were measured using calcium ion concentration detectors, magnesium ion concentration detectors, barium ion detectors, iron ion concentration detectors, and aluminum ion concentration detectors, respectively. The scale inhibition rate was calculated using the formula: (previous concentration - subsequent concentration) / previous concentration = scale inhibition rate. The results are shown in Table 1 below.

[0056] Table 1. Performance test results of products from Examples 1-10 and Comparative Examples 1-6

[0057] As can be seen from the data in Table 1, the scale inhibitors and dispersants of Examples 1-6 of this application exhibit excellent scale inhibition effects against five scaling ions (calcium, magnesium, barium, iron, and aluminum) at a high temperature of 250℃. Specifically, the scale inhibition rate for calcium and magnesium ions exceeds 97%, and the scale inhibition rate for barium, iron, and aluminum ions also reaches over 80%. Comparative Example 1, a phosphorus-containing product in the prior art, shows relatively excellent scale inhibition rates for calcium and magnesium ions, reaching close to 90%, but its scale inhibition rates for other ions are significantly insufficient, all below 60%. Therefore, the scale inhibitors and dispersants of this application demonstrate good scale inhibition effects against most scaling ions in the ash water of high-temperature coal gasification processes, exhibiting excellent overall performance.

[0058] The data in Table 1, comparing the data from Examples 1 to 6, shows that the scale inhibition effect can be further improved by optimizing the component ratio and the monomer molar ratio of the two composite copolymers.

[0059] By comparing the data from Example 6 and Comparative Example 2 in Table 1, it can be seen that the composite scale inhibitor and dispersant of this application exhibits significantly better performance in combination than that of a single component. This demonstrates that the modified polyaspartic acid-acrylic acid-EDTA copolymer and itaconic acid-styrene sulfonic acid copolymer, with a specific monomer molar ratio, can achieve a synergistic chelating effect, greatly enhancing the scale inhibition performance. Furthermore, a comparison of the data from Examples 6 and 3-7 shows that the scale inhibition effect of the composite scale inhibitor of this application is highly correlated with the monomer molar ratio of the two copolymers. A specific monomer molar ratio is required to achieve the desired synergistic effect; using other monomer molar ratios will significantly reduce the scale inhibition performance. Therefore, the composite scale inhibitor of this application requires a specific monomer molar ratio between the two copolymers to achieve a synergistic effect; otherwise, mutual group interference or steric hindrance will lead to a significant reduction in scale inhibition performance.

[0060] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A phosphorus-free scale inhibitor and dispersant, characterized in that, The phosphorus-free scale inhibitor and dispersant comprises the following components in the following proportions by mass: 24-28 parts of modified polyaspartic acid-acrylic acid-EDTA copolymer, 60-64 parts of itaconic acid-styrene sulfonic acid copolymer, and 2-3 parts of zinc sulfate.

2. The phosphorus-free scale inhibitor and dispersant according to claim 1, characterized in that, The preparation of the modified polyaspartic acid-acrylic acid-EDTA copolymer includes the following steps: S1-1. Weigh maleic anhydride and acrylic acid in a molar ratio of 1:1.4~1.5, add water to prepare a solution, add an initiator and ammonia water with a molar amount of 1.2~1.4 times that of maleic anhydride, react at 180~185℃ for 1~1.5h, cool and add sodium hydroxide to hydrolyze to obtain polyaspartic acid-acrylic acid copolymer. S1-2. Weigh polyaspartic acid-acrylic acid copolymer and EDTA at a molar ratio of 1:0.4~0.5, add water to prepare a solution, add a catalyst, react at 75~80℃ for 2 hours, and after cooling, obtain polyaspartic acid-acrylic acid-EDTA copolymer.

3. The phosphorus-free scale inhibitor and dispersant according to claim 2, characterized in that, In step S1-1, the molar ratio of maleic anhydride to acrylic acid is 1:1.42~1.

45.

4. The phosphorus-free scale inhibitor and dispersant according to claim 2, characterized in that, In step S1-1, the molar ratio of maleic anhydride to ammonia is 1:1.22~1.

25.

5. The phosphorus-free scale inhibitor and dispersant according to claim 2, characterized in that, In step S1-1, ammonium persulfate is selected as the initiator, and the amount of initiator added accounts for 1.8-2% of the total mass of maleic anhydride and acrylic acid.

6. The phosphorus-free scale inhibitor and dispersant according to claim 2, characterized in that, In steps S1-2, the molar ratio of polyaspartic acid-acrylic acid copolymer to EDTA is 1:0.46~0.

48.

7. The phosphorus-free scale inhibitor and dispersant according to claim 2, characterized in that, In steps S1-2, the catalyst used is 1-hydroxybenzotriazine, and the amount of catalyst added accounts for 5.6-5.8% of the total mass of polyaspartic acid-acrylic acid copolymer and EDTA.

8. The phosphorus-free scale inhibitor and dispersant according to claim 1, characterized in that, The preparation of the itaconic acid-styrene sulfonic acid copolymer includes the following steps: S2-1. Weigh itaconic acid and styrene sulfonic acid precisely according to a molar ratio of 2.2~2.4:1, add water, and heat to 70~75℃ to prepare a solution; S2-2. Add an initiator to the solution, then heat to 100~105℃, maintain the temperature for 1.8~2h, and after cooling, obtain itaconic acid-styrene sulfonic acid copolymer.

9. The phosphorus-free scale inhibitor and dispersant according to claim 8, characterized in that, In step S2-2, ammonium persulfate is selected as the initiator, and the amount of initiator added accounts for 6.2-6.5% of the total mass of itaconic acid and styrene sulfonic acid.

10. A method for preparing the phosphorus-free scale inhibitor and dispersant according to claim 1, characterized in that, Includes the following steps: S1. Preparation of modified polyaspartic acid-acrylic acid-EDTA copolymer; S2. Preparation of itaconic acid-styrene sulfonic acid copolymer; S3. Weigh each component according to the formula, mix them thoroughly, and then prepare a phosphorus-free scale inhibitor and dispersant.

Images