A low-phosphorus scale inhibitor suitable for high-silicon water and a preparation method thereof

Abstract

The application discloses a low-phosphorus scale inhibitor suitable for high-silicon water and a preparation method thereof, and relates to the technical field of water treatment. The low-phosphorus scale inhibitor suitable for high-silicon water comprises the following raw materials in parts by weight: hydrolyzed polymaleic anhydride 15-25 parts, a terpolymer 20-30 parts, polyepoxysuccinic acid 15-25 parts, acrylic acid-2-acrylamide-2-methylpropane sulfonic acid copolymer 10-20 parts, aminotri(methylene) phosphonic acid 15-20 parts, and deionized water 10-25 parts. The terpolymer is a copolymer composed of structural units provided by diallylamine, acrylic acid and sodium allylsulfonate, and has a number average molecular weight of 3000-4000. The application prepares a novel terpolymer by copolymerization of diallylamine, acrylic acid and sodium allylsulfonate under the action of ammonium persulfate. The scale inhibitor provided by the application has excellent scale inhibition performance for high-silicon water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a low-phosphorus scale inhibitor suitable for high-silicon water and a preparation method thereof. BACKGROUND

[0002] Silicon in nature often exists in the form of silicon dioxide and silicate, and the dissolved silicon dioxide in natural water mainly comes from the weathering of ores and rocks, and the content of silicon dioxide is usually less than 40 mg / L, but in some areas, it is as high as 40-180 mg / L. In industrial circulating water systems, general inorganic salt scale inhibitors cannot inhibit the formation of silicon scale, and once the silicon scale is formed, it is difficult to remove by chemical cleaning. When using high-silicon water, in order to ensure that the solubility of silicon dioxide is not exceeded, the circulating water system must be operated at a lower efficiency, which greatly limits the concentration multiple of the circulating water system, greatly increasing the water consumption and production cost. There are many studies on scale inhibitors at home and abroad, but there are few studies on scale inhibitors for SiO2 scale in China. Traditional organic phosphorus scale inhibitors and polymer dispersants, among which organic phosphorus substances are crystal modification type scale inhibitors, but the phosphorus components can easily cause microbial problems, and such traditional scale inhibitors have no significant ability to inhibit silicon deposition. The present application provides a new low-phosphorus scale inhibitor suitable for high-silicon water for the circulating water system using high-silicon water as raw water. SUMMARY

[0003] In view of the deficiencies in the prior art, the purpose of the present application is to provide a low-phosphorus scale inhibitor suitable for high-silicon water and a preparation method thereof.

[0004] To achieve the above-mentioned purpose, the present application realizes the following technical solutions:

[0005] A low-phosphorus scale inhibitor suitable for high-silicon water comprises the following raw materials in parts by weight: hydrolyzed polymaleic anhydride 15-25 parts, terpolymer 20-30 parts, polyepoxysuccinic acid 15-25 parts, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer 10-20 parts, aminotri(methylene) phosphonic acid 15-20 parts, and deionized water 10-25 parts.

[0006] The terpolymer is a copolymer composed of structural units provided by diallylamine, acrylic acid and sodium allylsulfonate, and the number average molecular weight is 3000-4000.

[0007] The terpolymer is prepared by the following method:

[0008] S1: 15-20 parts of diallylamine and 30-40 parts of purified water are added to a reaction kettle and stirred until dissolved;

[0009] S2: 10 parts by weight of sodium allyl sulfonate is dissolved in 15-20 parts by weight of purified water, and is added into the head tank 1;

[0010] S3: 12-18 parts by weight of ammonium persulfate is added into the head tank 2;

[0011] S4: 10 parts by weight of acrylic acid is dissolved in 10-15 parts by weight of purified water, and is added into the head tank 3;

[0012] S5: the reaction kettle of step S1 is warmed to 80-100℃, and the solutions in the head tank 1 and the head tank 2 are simultaneously slowly added into the reaction kettle, the dropping time is 1-2h, and after the dropping is completed, the reaction is continued for 1.5-2h;

[0013] S6: the solution in the head tank 3 is slowly added into the reaction kettle of step S5, the dropping time is 0.5-1h, and after the dropping is completed, the reaction is continued for 1-2h, thereby a terpolymer is obtained.

[0014] A preparation method of a low-phosphorus scale inhibitor suitable for high-silicon water, comprising the following steps:

[0015] The hydrolyzed polymaleic anhydride, the terpolymer, the polyepoxysuccinic acid, the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, the aminotri(methylene) phosphonic acid and the deionized water are sequentially added into a reaction kettle, and stirred for 20-40min, thereby obtaining the low-phosphorus scale inhibitor suitable for high-silicon water.

[0016] By adopting the above technical scheme, the present application has the following beneficial effects:

[0017] 1) The present application prepares a novel terpolymer by copolymerization of diallylamine, acrylic acid and sodium allyl sulfonate under the action of ammonium persulfate;

[0018] 2) The scale inhibitor provided by the present application has excellent scale inhibition performance for high-silicon water. DETAILED DESCRIPTION

[0019] The present application will be further described below in combination with examples, but the present application is not limited to these examples.

[0020] Example 1

[0021] Preparation of the terpolymer:

[0022] S1: 1800g of diallylamine and 3500g of purified water are added into a reaction kettle, and stirred until dissolved;

[0023] S2: 1000g of sodium allyl sulfonate is dissolved in 1800g of purified water, and is added into the head tank 1;

[0024] S3: 1500g of 40wt% ammonium persulfate is added into the head tank 2;

[0025] S4: 1000 g of acrylic acid was dissolved in 1200 g of purified water and added to tank 3;

[0026] S5: The reaction kettle of step S1 was warmed to 90°C, and the solutions in tanks 1 and 2 were simultaneously slowly added to the reaction kettle, the dropping time was 1.5 h, after the dropping was completed, the reaction was continued for 2 h;

[0027] S6: The solution in tank 3 was slowly added to the reaction kettle of step S5, the dropping time was 0.6 h, after the dropping was completed, the reaction was continued for 1.5 h, thus a terpolymer with a number average molecular weight of 3562 was obtained.

[0028] Example 2

[0029] Preparation of the terpolymer:

[0030] S1: 1500 g of diallylamine and 3000 g of purified water were added to the reaction kettle and stirred until dissolved;

[0031] S2: 1000 g of sodium allyl sulfonate was dissolved in 1500 g of purified water and added to tank 1;

[0032] S3: 1200 g of 40 wt% ammonium persulfate was added to tank 2;

[0033] S4: 1000 g of acrylic acid was dissolved in 1000 g of purified water and added to tank 3;

[0034] S5: The reaction kettle of step S1 was warmed to 80°C, and the solutions in tanks 1 and 2 were simultaneously slowly added to the reaction kettle, the dropping time was 1 h, after the dropping was completed, the reaction was continued for 1.5 h;

[0035] S6: The solution in tank 3 was slowly added to the reaction kettle of step S5, the dropping time was 0.5 h, after the dropping was completed, the reaction was continued for 1 h, thus a terpolymer with a number average molecular weight of 3025 was obtained.

[0036] Example 3

[0037] Preparation of the terpolymer:

[0038] S1: 2000 g of diallylamine and 4000 g of purified water were added to the reaction kettle and stirred until dissolved;

[0039] S2: 1000 g of sodium allyl sulfonate was dissolved in 2000 g of purified water and added to tank 1;

[0040] S3: 1800 g of 40 wt% ammonium persulfate was added to tank 2;

[0041] S4: 1000 g of acrylic acid was dissolved in 1500 g of purified water, and the solution was added to the head tank 3;

[0042] S5: The reaction kettle of step S1 was warmed to 100°C, and the solutions in the head tank 1 and the head tank 2 were simultaneously slowly added to the reaction kettle, the dropping time was 2 h, and after the dropping was completed, the reaction was continued for 2 h;

[0043] S6: The solution in the head tank 3 was slowly added to the reaction kettle of step S5, the dropping time was 1 h, and after the dropping was completed, the reaction was continued for 2 h, to obtain a terpolymer with a number average molecular weight of 3986.

[0044] Example 4

[0045] Preparation of a low-phosphorus scale inhibitor suitable for high-silicon water:

[0046] Hydrolyzed polymaleic anhydride 2000 g, terpolymer (prepared in Example 1) 2500 g, polyepoxysuccinic acid 2000 g, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer 1500 g, aminotri(methylene) phosphonic acid 1800 g, and deionized water 1500 g were sequentially added to a reaction kettle, stirred for 30 min, and uniformly mixed, to obtain a low-phosphorus scale inhibitor suitable for high-silicon water.

[0047] Example 5

[0048] Preparation of a low-phosphorus scale inhibitor suitable for high-silicon water:

[0049] Hydrolyzed polymaleic anhydride 1500 g, terpolymer (prepared in Example 2) 2000 g, polyepoxysuccinic acid 1500 g, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer 1000 g, aminotri(methylene) phosphonic acid 1500 g, and deionized water 1000 g were sequentially added to a reaction kettle, stirred for 20 min, and uniformly mixed, to obtain a low-phosphorus scale inhibitor suitable for high-silicon water.

[0050] Example 6

[0051] Preparation of a low-phosphorus scale inhibitor suitable for high-silicon water:

[0052] Hydrolyzed polymaleic anhydride 2500 g, terpolymer (prepared in Example 3) 3000 g, polyepoxysuccinic acid 2500 g, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer 2000 g, aminotri(methylene) phosphonic acid 2000 g, and deionized water 2500 g were sequentially added to a reaction kettle, stirred for 40 min, and uniformly mixed, to obtain a low-phosphorus scale inhibitor suitable for high-silicon water.

[0053] Comparative Example 1

[0054] The preparation method of the low-phosphorus scale inhibitor suitable for high-silicon water is basically the same as that in Example 4, except that the terpolymer (prepared in Example 1) is not added.

[0055] Comparative Example 2

[0056] The preparation method of the low-phosphorus scale inhibitor suitable for high-silicon water is basically the same as that in Example 4, except that the terpolymer (prepared in Example 1) is replaced with an equal amount of the allyl polyalkylene glycol-acrylic acid-sodium allyl sulfonate terpolymer prepared in Example 1 of Patent CN 105254821 A.

[0057] Comparative Example 3

[0058] The preparation method of the low-phosphorus scale inhibitor suitable for high-silicon water is basically the same as that in Example 4, except that the terpolymer (prepared in Example 1) is replaced with an equal amount of a terpolymer composed of structural units provided by allyl amine, acrylic acid, and sodium allyl sulfonate (with a number average molecular weight of 3492).

[0059] Comparative Example 4

[0060] The preparation method of the low-phosphorus scale inhibitor suitable for high-silicon water is basically the same as that in Example 4, except that 2500g of the terpolymer (prepared in Example 1) is replaced with 1200g of diallylamine, 660g of sodium allyl sulfonate, and 660g of acrylic acid.

[0061] Comparative Example 5

[0062] The preparation method of the low-phosphorus scale inhibitor suitable for high-silicon water is basically the same as that in Example 4, except that the terpolymer with a number average molecular weight of 3562 is replaced with an equal amount of a terpolymer with a number average molecular weight of 2702.

[0063] Comparative Example 6

[0064] The preparation method of the low-phosphorus scale inhibitor suitable for high-silicon water is basically the same as that in Example 4, except that the terpolymer with a number average molecular weight of 3562 is replaced with an equal amount of a terpolymer with a number average molecular weight of 4318.

[0065] The scale inhibition performance of the scale inhibitors prepared in the examples and comparative examples of the present application was tested. A 500mg / L (in terms of silicon dioxide) sodium silicate solution was prepared, and the dosage of the agent was 10mg / L and 20mg / L. The pH value of the solution was adjusted to 7.0±0.1 using hydrochloric acid and sodium hydroxide. The container containing the above solution was placed in a water bath at 40℃ for constant temperature for 20h. The solution was filtered using a 0.45μm microfiltration membrane, and the content of soluble silicon dioxide in the solution was determined using the silicon molybdenum blue spectrophotometric method. The scale inhibition rate was calculated, and the data of the scale inhibition rate is shown in Table 1.

[0066] Table 1

[0067]

[0068] The above merely describes the preferred embodiments of the present application and is not intended to limit the present application. Any equivalent changes, modifications and variations made by those skilled in the art without departing from the scope of the present application, which are disclosed above, are equivalent embodiments of the present application. Meanwhile, any equivalent changes, modifications and variations made by those skilled in the art without departing from the scope of the present application, which are disclosed above, are equivalent embodiments of the present application.

Claims

1. A low-phosphorus scale inhibitor suitable for high-silica water, characterized in that, The raw materials include the following parts by weight: 15-25 parts of hydrolyzed polymaleic anhydride, 20-30 parts of terpolymer, 15-25 parts of polyepoxysuccinic acid, 10-20 parts of acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, 15-20 parts of aminotrimethylenephosphonic acid, and 10-25 parts of deionized water. The terpolymer is a copolymer composed of structural units provided by diallylamine, acrylic acid and sodium allyl sulfonate, with a number-average molecular weight of 3000-4000. The terpolymer is prepared by the following method: S1: Add 15-20 parts of diallylamine and 30-40 parts of purified water to the reaction vessel and stir until dissolved; S2: Dissolve 10 parts by weight of sodium allyl sulfonate in 15-20 parts by weight of purified water and add it to high-level tank 1; S3: Add 12-18 parts by weight of ammonium persulfate to high-level tank 2; S4: Dissolve 10 parts by weight of acrylic acid in 10-15 parts by weight of purified water and add it to the high-level tank 3; S5: Heat the reactor from step S1 to 80-100℃, and slowly add the solutions from high-level tank 1 and high-level tank 2 into the reactor simultaneously for 1-2 hours. After the addition is complete, continue the reaction for 1.5-2 hours. S6: Slowly add the solution from the high-level tank 3 to the reaction vessel of step S5, with a dripping time of 0.5-1h. After the dripping is completed, continue the reaction for 1-2h to obtain the terpolymer.

2. The method for preparing the low-phosphorus scale inhibitor suitable for high-silica water according to claim 1, characterized in that, Includes the following steps: Hydrolyzed polymaleic anhydride, terpolymer, polyepoxysuccinic acid, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, aminotrimethylenephosphonic acid, and deionized water are added sequentially to a reaction vessel and stirred for 20-40 minutes to obtain a low-phosphorus scale inhibitor suitable for high-silica water.

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