Terpolymer scale inhibitor and preparation method thereof

Abstract

The invention discloses a terpolymer scale inhibitor and a preparation method thereof, and belongs to the technical field of polymer macromolecules and water treatment. The terpolymer scale inhibitor has the following structural general formula: # imgabs0 #, and in the formula, x, y and n are respectively any integer from 1 to 10. In addition, the invention also provides a preparation method of the terpolymer scale inhibitor, which comprises the following steps: mixing aconitic acid and water, stirring and dissolving at 50-55 DEG C, adding N, N-dimethylacrylamide and para aminobenzoic acid, heating to 65-85 DEG C, dropwise adding an initiator, and reacting at 65-90 DEG C to obtain the terpolymer scale inhibitor. The scale inhibitor provided by the invention is green and environment-friendly, and has excellent scale inhibition performance.

Description

Technical Field

[0001] The invention relates to the technical field of polymer macromolecules and water treatment, and in particular to a terpolymer scale inhibitor and a preparation method thereof. Background Art

[0002] At present, major oil fields in my country have entered the mid-to-late development stage. In order to maintain formation pressure and improve oil field extraction efficiency, water injection is required. In order to save water resources, oil field produced water is usually used, which has a complex composition and contains scale-forming ions such as calcium, magnesium, barium, and strontium. These inorganic salts precipitate and adhere to the inside of the pipeline and mechanical equipment, causing problems such as pipeline blockage and equipment damage. In particular, when injected into the formation, it causes formation scaling and blockage, and production decreases, which directly affects the benefits of oil field development.

[0003] At present, the main method to solve the scaling problem in the oil field production process is to add chemical agents such as scale inhibitors. With the development of science and technology and production needs, there are many types of scale inhibitors on the market. For a long time, phosphorus-containing scale inhibitors have been the most widely used, but they cause serious pollution to the environment. Green scale inhibitors refer to green production raw materials, production methods and production reactions. As environmental problems become increasingly serious, the country's attention to environmental protection is gradually increasing, so it is very important to develop an efficient and green scale inhibitor. How to efficiently prevent scale and be green and environmentally friendly is a technical problem that the existing technology needs to solve. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies, provide a terpolymer scale inhibitor and a preparation method thereof, and solve the technical problem of how to effectively inhibit scale and be environmentally friendly in the prior art.

[0005] In order to achieve the above technical purpose, the technical solution of the present invention provides a terpolymer scale inhibitor having the following general structural formula:

[0006]

[0007] In the formula, x, y, and n are any integers from 1 to 10 respectively.

[0008] In addition, the present invention also provides a method for preparing a terpolymer scale inhibitor, comprising the following steps:

[0009] Aconitic acid and water are mixed and stirred at 50-55°C to dissolve, and then N,N-dimethylacrylamide and p-aminobenzoic acid are added, and then the temperature is raised to 65-85°C and an initiator is added dropwise, and then the mixture is reacted at 65-90°C to obtain the terpolymer scale inhibitor.

[0010] In any embodiment, the molar ratio of the aconitic acid to the N,N-dimethylacrylamide is (1-3):1.

[0011] In any embodiment, the molar ratio of the aconitic acid to the p-aminobenzoic acid is (1-4):1.

[0012] In any embodiment, the initiator is ammonium persulfate.

[0013] In any embodiment, the amount of ammonium persulfate added is 8% to 15% of the total mass of aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid.

[0014] In any embodiment, the reaction time is 0.5h-2h.

[0015] In any embodiment, the time required for dropwise adding the initiator is 1 h to 2 h.

[0016] In any embodiment, the molar ratio of the aconitic acid, the N,N-dimethylacrylamide and the p-aminobenzoic acid is 4:2:1, and the added amount of the initiator is 12% of the total mass of the aconitic acid, the N,N-dimethylacrylamide and the p-aminobenzoic acid.

[0017] In any embodiment, the reaction temperature is 75° C., and the reaction time is 1 h.

[0018] Compared with the prior art, the beneficial effects of the present invention include: the present invention uses aconitic acid as a polymerization monomer, so that the polymer molecules have a large number of carboxylic acid groups, and the carboxylic acid group is the most important group that inhibits the formation of calcium scale. At the same time, due to the introduction of N,N-dimethylacrylamide and p-aminobenzoic acid, the polymer molecules have amide groups, which improves the solubility of the polymer and enhances the stability and durability of the polymer molecules. The monomer raw materials used in the preparation method of the present invention do not contain phosphorus groups, are non-toxic and harmless to the environment, and meet the requirements of green scale inhibitor production raw materials, production methods and production reactions. The obtained scale inhibitor is green and environmentally friendly, and has excellent scale inhibition performance. In addition, the scale inhibitor raw materials of the present invention are easy to obtain, safe and environmentally friendly, simple to prepare and easy to apply industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the infrared spectrum of the terpolymer scale inhibitor prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0020] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0022] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0023] This specific embodiment provides a terpolymer scale inhibitor, characterized in that it has the following general structural formula:

[0024]

[0025] In the formula, x, y, and n are any integers from 1 to 10 respectively.

[0026] This specific embodiment also proposes a method for preparing the above-mentioned terpolymer scale inhibitor, comprising the following steps:

[0027] Aconitic acid and water are mixed and stirred at 50-55° C. to dissolve, and then N,N-dimethylacrylamide and p-aminobenzoic acid are added, and then the temperature is raised to 65-85° C. and an initiator is added dropwise, and the addition of the initiator is completed within 1 h-2 h, and then the terpolymer scale inhibitor is reacted at 65-90° C. for 0.5 h-2 h to obtain the terpolymer scale inhibitor; the molar ratio of the aconitic acid to the N,N-dimethylacrylamide is (1-3):1; the molar ratio of the aconitic acid to the p-aminobenzoic acid is (1-4):1; the initiator is ammonium persulfate; and the amount of the ammonium persulfate added is 8%-15% of the total mass of the aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid.

[0028] In some embodiments, the molar ratio of the aconitic acid, the N,N-dimethylacrylamide and the p-aminobenzoic acid is 4:2:1, the amount of the initiator added is 12% of the total mass of the aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid, the reaction temperature is 75° C., and the reaction time is 1 h.

[0029] The present invention adopts an ammonium persulfate redox initiator system and obtains a green terpolymer by free radical copolymerization in aqueous solution. The reaction mechanism involved is:

[0030] During the reaction, the carbon-carbon double bonds of aconitic acid and N,N-dimethylacrylamide are broken, and then chain polymerization occurs. Ammonium persulfate acts as an initiator and becomes an active center, which undergoes an addition reaction with the monomer. Para-aminobenzoic acid undergoes an amidation reaction with the carboxylic acid group in aconitic acid. The reaction formula is as follows:

[0031]

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] In the present invention, reference is made to “some embodiments”, “this embodiment”, examples, etc., which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0034] If similar descriptions of "first / second" appear in the application documents, the following instructions are added. In the following description, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0035] In this embodiment, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, object A and / or object B may represent three situations: object A exists alone, object A and object B exist at the same time, and object B exists alone.

[0036] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific techniques or conditions are indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. If the manufacturer is not indicated in the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0037] Example 1

[0038] This embodiment provides a method for preparing a green terpolymer scale inhibitor, comprising the following steps:

[0039] Under air conditions, a certain amount of aconitic acid and pure water were added to the reactor, the temperature was raised to 55°C, and N,N-dimethylacrylamide and p-aminobenzoic acid were added after stirring at a uniform speed until they were completely dissolved. The molar ratio of aconitic acid to N,N-dimethylacrylamide was 1:1, and the molar ratio of aconitic acid to p-aminobenzoic acid was 2:1. After N,N-dimethylacrylamide and p-aminobenzoic acid were completely dissolved, the temperature was raised to 85°C, and ammonium persulfate initiator was added dropwise at a uniform speed. The addition was completed within 1.5 hours, and the amount of ammonium persulfate added was 10% of the total mass of aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid. The reaction temperature was controlled to 90°C, the reaction was carried out for 1 hour, and the reaction was cooled after the reaction was completed to obtain a reaction product solution. The product was purified by dialysis to remove unreacted small molecular monomers, and a copolymer scale inhibitor was obtained after freeze drying.

[0040] Example 2

[0041] This embodiment provides a method for preparing a green terpolymer scale inhibitor, comprising the following steps:

[0042] Under air conditions, a certain amount of aconitic acid and pure water were added to the reactor, the temperature was raised to 55°C, and N,N-dimethylacrylamide and p-aminobenzoic acid were added after stirring at a uniform speed until completely dissolved. The molar ratio of aconitic acid to N,N-dimethylacrylamide was 2:1, and the molar ratio of aconitic acid to p-aminobenzoic acid was 3:1. After N,N-dimethylacrylamide and p-aminobenzoic acid were completely dissolved, the temperature was raised to 80°C, and ammonium persulfate initiator was added dropwise at a uniform speed. The addition was completed within 1 hour. The amount of ammonium persulfate added was 8% of the total mass of aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid. The reaction temperature was controlled to 85°C, the reaction was carried out for 1.5 hours, and the reaction was cooled after the reaction was completed to obtain a reaction product solution. The product was purified by dialysis to remove unreacted small molecular monomers, and a copolymer scale inhibitor was obtained after freeze-drying.

[0043] Example 3

[0044] This embodiment provides a method for preparing a green terpolymer scale inhibitor, comprising the following steps:

[0045] Under air conditions, a certain amount of aconitic acid and pure water were added to the reactor, the temperature was raised to 55°C, and N,N-dimethylacrylamide and p-aminobenzoic acid were added after stirring at a uniform speed until they were completely dissolved. The molar ratio of aconitic acid to N,N-dimethylacrylamide was 2:1, and the molar ratio of aconitic acid to p-aminobenzoic acid was 4:1. After N,N-dimethylacrylamide and p-aminobenzoic acid were completely dissolved, the temperature was raised to 70°C, and ammonium persulfate initiator was added dropwise at a uniform speed. The addition was completed within 1 hour. The amount of ammonium persulfate added was 12% of the total mass of aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid. The reaction temperature was controlled to 70°C, the reaction was carried out for 45 minutes, and the reaction was cooled after the reaction was completed to obtain a reaction product solution. The product was purified by dialysis to remove unreacted small molecular monomers, and a copolymer scale inhibitor was obtained after freeze drying.

[0046] Figure 1 This is the infrared spectrum of the scale inhibitor prepared in this example. Figure 1 Found 3443.8cm -1 、1723.1cm -1 、1643.1cm -1 、1403.4cm -1 、1219.1cm -1 、1117.6cm -1 The characteristic absorption peaks of 3443.8cm -1 and 1643.1cm -1 They are the NH stretching vibration absorption peak in the amide group and the stretching vibration absorption peak of C=O. 1723.1cm -1 and 1117.6cm -1The vibrations are caused by the stretching vibration peaks of C=O and CO in the carboxylic acid group, 1403.4 cm -1 and 1219.1cm -1 It is the characteristic absorption peak of CN stretching vibration. At the same time, no 1620-1640cm -1 The C=C absorption peak indicates that the monomers have been copolymerized to obtain the scale inhibitor of this example.

[0047] Example 4

[0048] This embodiment provides a method for preparing a green terpolymer scale inhibitor, comprising the following steps:

[0049] Under air conditions, a certain amount of aconitic acid and pure water were added to the reactor, the temperature was raised to 55°C, N,N-dimethylacrylamide and p-aminobenzoic acid were added after stirring at a uniform speed until completely dissolved, the molar ratio of aconitic acid to N,N-dimethylacrylamide was 3:1, and the molar ratio of aconitic acid to p-aminobenzoic acid was 4:1. After N,N-dimethylacrylamide and p-aminobenzoic acid were completely dissolved, the temperature was raised to 70°C, and ammonium persulfate initiator was added dropwise at a uniform speed, and the addition was completed within 1 hour. The amount of ammonium persulfate added was 12% of the total mass of aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid. The reaction temperature was controlled to 80°C, the reaction was carried out for 1 hour, and the reaction was cooled after the reaction was completed to obtain a reaction product solution. The product was purified by dialysis to remove unreacted small molecular monomers, and a polymer scale inhibitor was obtained after freeze drying.

[0050] Comparative Example 1

[0051] This comparative example proposes a method for preparing a scale inhibitor, which differs from Example 3 in that p-aminobenzoic acid is not added, and comprises the following steps:

[0052] Under air conditions, add a certain amount of aconitic acid and pure water to the reactor, raise the temperature to 55°C, stir at a uniform speed until completely dissolved, and then add N,N-dimethylacrylamide. The amount of aconitic acid is the same as that in Example 3, and the amount of N,N-dimethylacrylamide is the sum of the amounts of N,N-dimethylacrylamide and p-aminobenzoic acid in Example 3. After N,N-dimethylacrylamide is completely dissolved, the temperature is raised to 70°C, and ammonium persulfate initiator is added dropwise at a uniform speed. The addition is completed within 1 hour, and the amount of ammonium persulfate added is 12% of the total mass of aconitic acid and N,N-dimethylacrylamide. The reaction temperature is controlled to 70°C, the reaction is carried out for 45 minutes, and the reaction is cooled after the reaction is completed to obtain a reaction product solution. The product is purified by dialysis to remove unreacted small molecular monomers, and a scale inhibitor is obtained after freeze-drying.

[0053] Comparative Example 1

[0054] This comparative example proposes a method for preparing a scale inhibitor, which differs from Example 3 in that N,N-dimethylacrylamide is not added, and comprises the following steps:

[0055] Under air conditions, add a certain amount of aconitic acid and pure water to the reactor, raise the temperature to 55°C, stir at a uniform speed until completely dissolved, then add p-aminobenzoic acid, the amount of aconitic acid is the same as that in Example 3, and the amount of p-aminobenzoic acid is the sum of the amounts of N,N-dimethylacrylamide and p-aminobenzoic acid in Example 3. After the p-aminobenzoic acid is completely dissolved, raise the temperature to 70°C, uniformly add ammonium persulfate initiator, and complete the addition within 1 hour. The amount of ammonium persulfate added is 12% of the total mass of aconitic acid and p-aminobenzoic acid. Control the reaction temperature to 70°C, react for 45 minutes, cool after the reaction is completed, and obtain a reaction product solution. The product is purified by dialysis to remove unreacted small molecular monomers, and a scale inhibitor is obtained after freeze-drying.

[0056] Evaluation of scale inhibition performance

[0057] Adopted standard: National standard "GBT 16632-2019 Determination of scale inhibition performance of water treatment agents-Calcium carbonate deposition method".

[0058] Water sample: produced water from oilfield. Water quality composition is shown in Table 1.

[0059] Table 1 Water quality components of oilfield produced water samples (unit: mg / L)

[0060]

[0061] The scale inhibition ability of the polymer scale inhibitor prepared in Examples 1-4 and the scale inhibitor of Comparative Examples 1-2 on calcium carbonate was measured, and the test results are recorded in Table 2.

[0062] Table 2 Scale inhibition performance test results

[0063] Serial number Antiscalant dosage (mg / L) Calcium carbonate scale inhibition rate Example 1 30 96.5％ Example 2 30 97.2％ Example 3 30 99.6％ Example 4 30 98.6％ Comparative Example 1 30 56.8％ Comparative Example 2 30 52.1％

[0064] As can be seen from Table 1, the green ternary copolymer obtained by free radical copolymerization of aqueous solution using aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid as raw materials and ammonium persulfate redox initiator has good scale inhibition performance for calcium carbonate; when the scale inhibitor dosage is 30 mg / L, the scale inhibition rate for calcium carbonate is as high as 99.6%, achieving the prevention of scale formation in high hardness and high carbonate water at a relatively low concentration.

[0065] In addition, it can be seen from the above results that the scale inhibition effect of Example 3 of the present invention is better, indicating that when the molar ratio of aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid monomers is 4:2:1 and the amount of ammonium persulfate added is 12% of the total mass of aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid, the product has a higher scale inhibition rate.

[0066] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A terpolymer scale inhibitor, characterized in that: It has the following general structural formula: In the formula, x, y, and n are any integers from 1 to 10 respectively.

2. A method for preparing a terpolymer scale inhibitor, characterized in that: The following steps are involved: Aconitic acid and water are mixed and stirred at 50-55°C to dissolve, and then N,N-dimethylacrylamide and p-aminobenzoic acid are added, and then the temperature is raised to 65-85°C and an initiator is added dropwise, and then the mixture is reacted at 65-90°C to obtain the terpolymer scale inhibitor.

3. The method for preparing the terpolymer scale inhibitor according to claim 2, characterized in that: The molar ratio of the aconitic acid to the N,N-dimethylacrylamide is (1-3):

1.

4. The method for preparing the terpolymer scale inhibitor according to claim 2, characterized in that: The molar ratio of the aconitic acid to the p-aminobenzoic acid is (1-4):

1.

5. The method for preparing the terpolymer scale inhibitor according to claim 2, characterized in that: The initiator is ammonium persulfate.

6. The method for preparing the terpolymer scale inhibitor according to claim 2, characterized in that: The amount of ammonium persulfate added is 8% to 15% of the total mass of aconitic acid, N,N-dimethylacrylamide and p-aminobenzoic acid.

7. The method for preparing the terpolymer scale inhibitor according to claim 2, characterized in that: The reaction time is 0.5h-2h.

8. The method for preparing the terpolymer scale inhibitor according to claim 2, characterized in that: The time required for dropwise addition of the initiator is 1 h to 2 h.

9. The method for preparing the terpolymer scale inhibitor according to claim 2, characterized in that: The molar ratio of the aconitic acid, the N,N-dimethylacrylamide and the p-aminobenzoic acid is 4:2:1, and the added amount of the initiator is 12% of the total mass of the aconitic acid, the N,N-dimethylacrylamide and the p-aminobenzoic acid.

10. The method for preparing the terpolymer scale inhibitor according to claim 7, characterized in that: The reaction temperature is 75° C., and the reaction time is 1 h.

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