Preparation method of phosphorus-free comprehensive scale inhibitor

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a preparation method of a non-phosphorus comprehensive scale inhibitor. In order to achieve the purpose, the technical scheme adopted by the invention is as follows: according to the preparation method of the non-phosphorus comprehensive scale inhibitor, used polymeric monomers are acrylic acid and 2-allyloxyethanol, an initiator and a reducing agent are further included, the initiator is sodium persulfate, and the reducing agent is sodium hydrogen sulfite; the preparation method comprises the following steps: adding deionized water into a reaction container, stirring and heating to 80-85 DEG C, simultaneously dropwise adding a monomer, an initiator and a reducing agent into water through a peristaltic pump, and controlling the mass ratio of acrylic acid to 2-allyloxyethanol to be (4-19): 1; the temperature is kept for 40 min after dropwise adding is completed, the copolymer scale inhibitor is obtained after the temperature is reduced to the room temperature, and the viscosity average molecular weight of the copolymer scale inhibitor is 5000-6000. Molecules of the prepared polymer scale inhibitor do not contain any organic phosphine or inorganic phosphate, phosphorus emission can be greatly reduced, and the environmental problem caused by an existing phosphorus-containing scale inhibitor is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a method for preparing a phosphorus-free comprehensive scale inhibitor. Background Art

[0002] With the rapid development of my country's economy and the sharp increase in population, water shortage has become an important factor restricting China's economic construction and development. The acceleration of industrialization has led to an increase in industrial water consumption, of which industrial cooling water is a major item of industrial water, and circulating cooling water accounts for about 80% of industrial water. Saving industrial circulating cooling water is the main way to rationally utilize water resources.

[0003] During the long-term circulation of industrial circulating cooling water, water evaporates and concentrates continuously, and Ca 2+ Mg 2+ 、CO3 2- The concentration of plasma will continue to grow due to the evaporation loss of part of the water. When these ions reach a high concentration, a scale deposit layer will form on the surface of the equipment, resulting in a reduction in the cross-sectional area of ​​the pipe, which in turn affects the heat transfer efficiency and cooling effect. In severe cases, it may even cause pipe leakage and perforation, endangering industrial production safety. Calcium carbonate scale, calcium sulfate scale, and calcium phosphate scale are the main components of scale in industrial circulating cooling water systems. They have strong viscosity and low solubility in the circulating water system, making them very easy to adhere to and deposit on the surface of the pipe, resulting in a decrease in the heat exchange capacity of the cooling water. In order to effectively inhibit the formation of these calcium scales and improve the quality of cooling water, adding scale inhibitors is considered to be the most common and effective scale prevention method.

[0004] At present, the scale inhibitors widely used in industrial circulating cooling water treatment are mainly organic phosphine scale inhibitors and polycarboxylic acid scale inhibitors. At present, some commonly used scale inhibitors on the market can only have a good effect on one or two types of scales, but the comprehensive scale inhibition effect is not ideal. For example, a certain dose of polyacrylic acid only has a good scale inhibition effect on calcium carbonate and calcium sulfate scales, but has a poor scale inhibition effect on calcium phosphate scales. Therefore, it is very necessary to develop a comprehensive scale inhibitor that has a good scale inhibition effect on calcium carbonate scale, calcium sulfate scale, and calcium phosphate scale. Organic phosphine scale inhibitors have excellent scale inhibition performance and are most widely used in the field of water treatment. However, organic phosphine scale inhibitors are rich in P and easily cause eutrophication of water bodies. With the continuous improvement of national environmental protection standards and people's environmental awareness, the use of organic phosphine scale inhibitors has gradually been restricted. In order to achieve the coordinated development of efficient water treatment and environmental friendliness, scale inhibitors have begun to develop and develop in the direction of phosphorus-free or low-phosphorus to reduce phosphorus emissions.

[0005] Therefore, it is of great significance to develop a new type of comprehensive, efficient and environmentally friendly phosphorus-free water treatment scale inhibitor. Summary of the invention

[0006] In view of the above-mentioned deficiencies of existing scale inhibitors, the present invention provides a method for preparing a phosphorus-free comprehensive scale inhibitor. The obtained copolymer has good scale inhibition performance against calcium carbonate, calcium sulfate and calcium phosphate, and effectively prevents the formation of calcium scale in industrial circulating cooling water.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows: The preparation method of the phosphorus-free comprehensive scale inhibitor of the present invention comprises the following polymerization monomers: acrylic acid and 2-allyloxyethanol; an initiator and a reducing agent; the initiator is sodium persulfate; and the reducing agent is sodium bisulfite; Deionized water is added into the reaction container, stirred and heated to 80-85°C, and monomers, initiators and reducing agents are simultaneously added into the water by a peristaltic pump, and the mass ratio of acrylic acid and 2-allyloxyethanol added is (4-19):1; after the addition is completed, the temperature is kept warm for 40 minutes, and after cooling to room temperature, a copolymer scale inhibitor is obtained, and the viscosity-average molecular weight of the copolymer scale inhibitor is 5000-6000.

[0008] According to the preparation method of the phosphorus-free comprehensive scale inhibitor, the mass of sodium persulfate added is 1.2-1.6% of the sum of the mass of monomer acrylic acid and 2-allyloxyethanol.

[0009] According to the preparation method of the phosphorus-free comprehensive scale inhibitor, the mass of sodium bisulfite added is 9-9.5% of the sum of the mass of monomer acrylic acid and 2-allyloxyethanol.

[0010] According to the preparation method of the phosphorus-free comprehensive scale inhibitor, the preparation method of the copolymer described in the present invention includes the following process: the mass ratio of monomer acrylic acid to 2-allyloxyethanol is (4~9):1.

[0011] According to the preparation method of the phosphorus-free comprehensive scale inhibitor, the mass concentration of the sodium persulfate added is 10-20%.

[0012] According to the preparation method of the phosphorus-free comprehensive scale inhibitor, further, the mass concentration of the sodium bisulfite added is 25-35%.

[0013] According to the method for preparing the phosphorus-free comprehensive scale inhibitor, the mass of the deionized water added to the reaction container is 1 to 1.5 times the mass of the monomer.

[0014] According to the preparation method of the phosphorus-free comprehensive scale inhibitor, monomers acrylic acid and 2-allyloxyethanol, an initiator sodium persulfate and a reducing agent sodium bisulfite are simultaneously added dropwise into deionized water by a peristaltic pump, and the monomer addition time is 60-65 minutes; wherein the initiator and the reducing agent are added dropwise 1-3 minutes before the monomer acrylic acid and 2-allyloxyethanol mixture, and continue to be added dropwise for 1-5 minutes after the monomer addition is completed, and the total addition time of the initiator and the reducing agent is 63-73 minutes.

[0015] According to the preparation method of the phosphorus-free comprehensive scale inhibitor, the monomer content in the acrylic acid monomer is 96.88%, and the monomer content in the 2-allyloxyethanol is 98%.

[0016] The technical features and beneficial effects of the present invention are as follows: The water-soluble copolymer prepared by the present invention uses acrylic acid and 2-allyloxyethanol as raw materials, and the molecular structure contains carboxyl, hydroxyl and ether groups with good scale inhibition and dispersibility. 2+ It has a strong chelating and dispersing effect, effectively reduces the formation of calcium scale, and has low cost and easy operation.

[0017] The copolymer prepared by the invention has simple synthesis process, high conversion rate, low cost and good water solubility, and has good scale inhibition ability for calcium carbonate, calcium sulfate and calcium phosphate, thus effectively solving the scaling problem in the circulating cooling water system.

[0018] The polymer scale inhibitor prepared by the present invention does not contain any organic phosphine or inorganic phosphate in the molecule, which can greatly reduce the emission of phosphorus and avoid the environmental problems caused by the existing phosphorus-containing scale inhibitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the H-NMR spectrum of the copolymer scale inhibitor prepared in Example 1.

[0020] Figure 2 This is the NMR carbon spectrum of the copolymer scale inhibitor prepared in Example 1.

[0021] Figure 3 This is the H-NMR spectrum of the copolymer scale inhibitor prepared in Example 2.

[0022] Figure 4 This is the NMR carbon spectrum of the copolymer scale inhibitor prepared in Example 2.

[0023] Figure 5 This is the H-NMR spectrum of the copolymer scale inhibitor prepared in Example 3.

[0024] Figure 6 This is the NMR carbon spectrum of the copolymer scale inhibitor prepared in Example 3.

[0025] Figure 7This is the H-NMR spectrum of the copolymer scale inhibitor prepared in Comparative Example 1.

[0026] Figure 8 This is the NMR carbon spectrum of the copolymer scale inhibitor prepared in Comparative Example 1. DETAILED DESCRIPTION

[0027] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the following is a specific implementation. Examples are provided to further illustrate the present invention, but are not limited thereto.

[0028] The monomer acrylic acid, initiator sodium persulfate, and reducing agent sodium bisulfite used in the examples are all from Shandong Taihe Water Treatment Technology Co., Ltd.; 2-allyloxyethanol is from Shanghai MacLean Biochemical Technology Co., Ltd. The acrylic acid content is 96.88%, and the 2-allyloxyethanol content is 98%. Example

[0029] (1) Weigh 205.0 g of deionized water into a four-necked flask and heat it to 83°C.

[0030] (2) Weigh 19.99 gg of 2-allyloxyethanol and dissolve it in 181.99 g of acrylic acid. Dissolve 3.0 g of initiator sodium persulfate in water. Dissolve 18 g of reducing agent sodium bisulfite in water. Use a peristaltic pump to simultaneously drop the monomer, initiator and reducing agent into deionized water. The dropping time of the mixture of monomer acrylic acid and 2-allyloxyethanol is 60 min. The initiator and reducing agent are added simultaneously and 2 min in advance of the monomer. After the monomer is added, continue to drop for 1 min. The total drop time is 63 min. During the dropping process, the temperature is controlled at 83±2°C.

[0031] (3) After the addition of the initiator and the reducing agent was completed, the temperature was kept at room temperature for 40 minutes and then cooled to room temperature to obtain a light yellow transparent liquid, which was acrylic acid / 2-allyloxyethanol copolymer. The viscosity-average molecular weight of the obtained product was 5793, the chelating value was 478.31 mg / g, and the dispersing power was 100.74 mg / g.

[0032] The H NMR spectrum and C NMR spectrum of the acrylic acid / 2-allyloxyethanol copolymer prepared in this example are shown as follows: Figure 1 , Figure 2 shown. Example

[0033] (1) Weigh 200.0 g of deionized water into a four-necked flask and heat it to 83°C.

[0034] (2) Weigh 29.99 g of 2-allyloxyethanol and dissolve it in 171.88 g of acrylic acid. Dissolve 3.0 g of initiator sodium persulfate in water. Dissolve 18 g of reducing agent sodium bisulfite in water. Use a peristaltic pump to simultaneously drop the monomer, initiator and reducing agent into deionized water. The dropping time of the mixture of monomer acrylic acid and 2-allyloxyethanol is 63 min. The initiator and reducing agent are added simultaneously and 2 min in advance of the monomer. After the monomer is added, continue to drop for 5 min, for a total of 70 min. During the dropping process, the temperature is controlled at 83±2°C.

[0035] (3) After the addition of the initiator and the reducing agent was completed, the temperature was kept at room temperature for 40 minutes and then cooled to room temperature to obtain a light yellow transparent liquid, which was acrylic acid / 2-allyloxyethanol copolymer. The viscosity-average molecular weight of the obtained product was 5590, the chelating value was 543.96 mg / g, and the dispersing power was 98.16 mg / g.

[0036] The H NMR spectrum and C NMR spectrum of the acrylic acid / 2-allyloxyethanol copolymer prepared in this example are shown as follows: Figure 3 , Figure 4 shown. Example

[0037] (1) Weigh 200.0 g of deionized water into a four-necked flask and heat it to 83°C.

[0038] (2) Weigh 39.98 g of 2-allyloxyethanol and dissolve it in 161.77 g of acrylic acid. Dissolve 3.0 g of initiator sodium persulfate in water. Dissolve 18 g of reducing agent sodium bisulfite in water. Use a peristaltic pump to simultaneously drop the monomer, initiator and reducing agent into deionized water. The dropping time of the mixture of monomer acrylic acid and 2-allyloxyethanol is 60 min. The initiator and reducing agent are added simultaneously and 2 min in advance of the monomer. After the monomer is added, continue to drop for 3 min. The total drop time is 65 min. During the dropping process, the temperature is controlled at 83±2°C.

[0039] (3) After the addition of the initiator and the reducing agent was completed, the temperature was kept at room temperature for 40 minutes and then cooled to room temperature to obtain a light yellow transparent liquid, which was acrylic acid / 2-allyloxyethanol copolymer. The viscosity-average molecular weight of the obtained product was 5950, the chelating value was 879.96 mg / g, and the dispersing power was 87.83 mg / g.

[0040] The H NMR spectrum and C NMR spectrum of the acrylic acid / 2-allyloxyethanol copolymer prepared in this example are shown as follows: Figure 3 , Figure 4 shown.

[0041] (1) Weigh 195.0 g of deionized water into a four-necked flask and heat it to 83°C.

[0042] (2) Weigh 10 g of 2-allyloxyethanol and dissolve it in 192.11 g of acrylic acid. Dissolve 3.0 g of initiator sodium persulfate in water. Dissolve 18 g of reducing agent sodium bisulfite in water. Use a peristaltic pump to simultaneously drop the monomer, initiator and reducing agent into deionized water. The dropping time of the mixture of monomer acrylic acid and 2-allyloxyethanol is 62 min. The initiator and reducing agent are added simultaneously and 2 min in advance of the monomer. After the monomer is added, continue to drop for 4 min, for a total of 68 min. During the dropping process, the temperature is controlled at 83±2°C.

[0043] (3) After the addition of the initiator and the reducing agent was completed, the temperature was kept at room temperature for 40 minutes and then cooled to room temperature to obtain a light yellow transparent liquid, which was acrylic acid / 2-allyloxyethanol copolymer. The viscosity-average molecular weight of the obtained product was 5537, the chelating value was 416.89 mg / g, and the dispersing power was 103.59 mg / g.

[0044] The H NMR spectrum and C NMR spectrum of the acrylic acid / 2-allyloxyethanol copolymer prepared in this example are shown as follows: Figure 7 , Figure 8 shown.

[0045] Comparative Example 2 is commercially available polyacrylic acid PAA produced by Shandong Taihe Science and Technology Co., Ltd. It is a light yellow transparent liquid with a content of 50%.

[0046] In the above embodiments, the national standard GB / T16632-2019 "Determination of scale inhibition performance of water treatment agents - calcium carbonate deposition method" is used to evaluate the scale inhibition performance of calcium carbonate, and the dosage of the polymer is 5ppm; the industry standard Q / SY 126-2014 "Technical Specifications for Corrosion and Scale Inhibitors for Oilfield Water Treatment" is used to evaluate the scale inhibition performance of calcium sulfate, and the dosage of the polymer is 10ppm; the national standard GB / T22626-2008 "Determination of scale inhibition performance of water treatment agents - calcium phosphate deposition method" and the national standard GB / T 6913-2008 "Boiler water and cooling water analysis method - determination of phosphate" are used to evaluate the scale inhibition performance of calcium phosphate, and the dosage of the polymer is 10ppm.

[0047] Table 1 shows the scale inhibition rates of the embodiments and comparative examples for calcium carbonate, calcium sulfate and calcium phosphate.

[0048] Table 1 Comparison of scale inhibition effects of different scale inhibitors Antiscalant Calcium carbonate 5ppm Calcium sulfate 10ppm Calcium phosphate 10ppm Example 1 49.10% 100.0 % 96.29 % Example 2 49.73 % 95.64 % 88.41 % Example 3 49.64 % 94.61 % 94.11 % Comparative Example 1 50.19% 100.0% 18.95% Comparative Example 2 46.15% 99.14% 3.47% It can be seen from Table 1 that the water-soluble copolymer prepared with acrylic acid and 2-allyloxyethanol as raw materials has good scale inhibition performance and can effectively reduce the formation of calcium scale.

[0049] The copolymer prepared by the invention has simple synthesis process, high conversion rate, low cost and good water solubility, and has good scale inhibition ability for calcium carbonate, calcium sulfate and calcium phosphate, thus effectively solving the scaling problem in the circulating cooling water system.

[0050] The polymer scale inhibitor prepared by the present invention does not contain any organic phosphine or inorganic phosphate in the molecule, which can greatly reduce the emission of phosphorus and avoid the environmental problems caused by the existing phosphorus-containing scale inhibitor.

Claims

1. A method for preparing a phosphorus-free comprehensive scale inhibitor, wherein the raw material polymerization monomers are acrylic acid and 2-allyloxyethanol, characterized in that: It also includes an initiator and a reducing agent, wherein the initiator is sodium persulfate and the reducing agent is sodium bisulfite; Deionized water is added into the reaction container, stirred and heated to 80-85°C, and monomers, initiators and reducing agents are simultaneously added into the water by a peristaltic pump, and the mass ratio of acrylic acid and 2-allyloxyethanol added is (4-19):1; after the addition is completed, the temperature is kept warm for 40 minutes, and after cooling to room temperature, a copolymer scale inhibitor is obtained, and the viscosity-average molecular weight of the copolymer scale inhibitor is 5000-6000.

2. The method for preparing the phosphorus-free comprehensive scale inhibitor according to claim 1, characterized in that: The mass of sodium persulfate added is 1.2-1.6% of the sum of the mass of monomer acrylic acid and 2-allyloxyethanol.

3. The method for preparing the phosphorus-free comprehensive scale inhibitor according to claim 1, characterized in that: The mass of sodium bisulfite added is 9-9.5% of the sum of the mass of monomer acrylic acid and 2-allyloxyethanol.

4. The method for preparing the phosphorus-free comprehensive scale inhibitor according to claim 1, characterized in that: The preparation method of the copolymer described in the present invention comprises the following process: the mass ratio of monomer acrylic acid to 2-allyloxyethanol is (4-9):

1.

5. The method for preparing the phosphorus-free comprehensive scale inhibitor according to claim 1 or 2, characterized in that: The mass concentration of sodium persulfate added is 10~20%.

6. The method for preparing the phosphorus-free comprehensive scale inhibitor according to claim 1 or 3, characterized in that: Furthermore, the mass concentration of the sodium bisulfite added is 25-35%.

7. The method for preparing the phosphorus-free comprehensive scale inhibitor according to claim 1, characterized in that: The mass of the deionized water added to the reaction container is 1 to 1.5 times the mass of the monomer.

8. The method for preparing the phosphorus-free comprehensive scale inhibitor according to claim 1, characterized in that: The monomers acrylic acid and 2-allyloxyethanol, the initiator sodium persulfate and the reducing agent sodium bisulfite are simultaneously added dropwise into the deionized water by a peristaltic pump, and the monomer addition time is 60-65 min. The initiator and the reducing agent are added dropwise 1-3 min before the monomer acrylic acid and 2-allyloxyethanol mixture, and are continued to be added dropwise for 1-5 min after the monomer addition is completed. The total addition time of the initiator and the reducing agent is 63-73 min.

9. The method for preparing the phosphorus-free comprehensive scale inhibitor according to claim 1, characterized in that: The monomer content of acrylic acid monomer is 96.88%, and the monomer content of 2-allyloxyethanol is 98%.

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