High-hardness water scale inhibition method and application thereof

Abstract

The invention relates to the technical field of industrial water treatment, and discloses a high-hardness water scale inhibition method and application thereof.The method comprises the steps that a scale inhibitor and high-hardness water are mixed; the scale inhibitor comprises a compound shown as a formula (I), # imgabs0 # in the formula (I), R1 is selected from C8-C22 alkyl; each R2 is independently selected from H, 2-hydroxypropyl or methyl; r3 and R4 are independently selected from H,-PO3M2 or-PO3HM, and R3 and R4 are not H at the same time; m is selected from any one of Li, Na, K and NH4; m is selected from any integer of 1-10, n is selected from any integer of 1-10, z is selected from any integer of 0-9, and the sum of m, n and z is any integer of 5-11. The method has the advantages of no biotoxicity, no color, no special smell and the like, and has an excellent scale inhibition effect on multivalent metals such as Ca < 2 + >, Ba < 2 + > and Sr < 2 + > in a complex water body.

Description

Technical Field

[0001] The invention relates to the technical field of industrial water treatment, and in particular to a method for preventing scale from forming in high-hardness water and application thereof. Background Art

[0002] During the long-term operation and concentration of industrial circulating water, the concentration of scale-forming ions increases, and the precipitated scale salts are deposited on the surface of pipelines and other equipment, which not only affects the heat exchange efficiency, but also easily blocks pipelines and causes problems such as under-scale corrosion, which brings serious safety hazards and economic losses to industrial production. At the same time, in oilfield production, there is often a problem that inorganic scale, especially calcium sulfate scale, barium sulfate scale, strontium sulfate scale and other inorganic scales block the near-well area and wellbore, causing downhole blockage, affecting oil and gas production, and even causing serious consequences such as the scrapping of oil and water wells. Therefore, scale inhibitors play an important role in industrial and oilfield production.

[0003] Scale inhibitors mainly achieve the purpose of scale inhibition by means of chelation, adsorption dispersion and scale salt lattice distortion. Scale inhibitors commonly used on the market are mainly used in environments with low hardness such as industrial circulating water. Polymer scale inhibitors have the advantages of superior performance and good thermal stability. They work with organic phosphonates to inhibit the precipitation of scale ions and the formation of scale salts through complexation. They have become a research hotspot for water treatment agents. CN11621278A discloses a macrocyclic compound supramolecular scale dissolving agent system. Although the scale dissolving agent is effective for Ba 2+ , Sr 2+ It has excellent anti-scaling performance, but poor solubility. It is necessary to add various additives such as cosolvents and complexing agents to make the system stably dispersed in the water body, and the system is not suitable for environments with large fluctuations in water quality. CN107522298A discloses a composite corrosion inhibitor composed of a copolymer, carboxymethyl and cyclodextrin derivatives. This system is also not suitable for harsh water quality environments with high hardness and high concentration. CN111960556A discloses a high-hardness water phosphorus-free scale inhibitor, which is composed of maleic anhydride-β-cyclodextrin-sodium styrene sulfonate copolymer, azole derivatives, zinc chloride, amino acid polymers and additives. Although the scale inhibitor has good scale inhibition performance in high-hardness water, the system is complex, and the zinc salts and azole derivatives therein are biologically toxic.

[0004] Existing scale inhibitors are usually used in the field of cooling circulating water, with limited application scope and poor effect in environments with high hardness and large changes in water quality. Developing new safe and environmentally friendly scale inhibitors with no toxic side effects on organisms, solving the current problem of phosphorus-free scale inhibitors causing scale formation in highly concentrated and high hardness industrial water and blockage in oilfield wellbore, ensuring safe production and meeting increasingly stringent environmental protection requirements, has become a new demand for scale inhibitor development. Summary of the invention

[0005] The purpose of the present invention is to overcome a series of problems existing in the prior art, such as limited scale inhibition effect of highly concentrated and high-hardness industrial water, poor safety and environmental protection, serious scaling of highly mineralized water in oil field exploitation in near-wellbore areas such as wellbore, pipeline blockage, and difficulty in acidification and deblocking, and to provide a method for high-hardness water scale inhibition and its application, which can effectively inhibit the scaling problem of high-hardness water and has the advantage of being environmentally friendly.

[0006] In order to achieve the above object, the first aspect of the present invention provides a method for preventing scale in hard water, the method comprising: mixing a scale inhibitor with hard water; the scale inhibitor comprises a compound represented by formula (I),

[0007]

[0008] Wherein, in formula (I),

[0009] R1 is selected from C8-C 22 The alkyl group;

[0010] Each R2 is independently selected from H, 2-hydroxypropyl or methyl;

[0011] R3 and R4 are each independently selected from H, -PO3M2 or -PO3HM, and R3 and R4 are not H at the same time;

[0012] M is selected from any one of Li, Na, K, and NH4;

[0013] m is selected from any integer of 1-10, n is selected from any integer of 1-10, z is selected from any integer of 0-9, and the sum of m, n and z is any integer of 5-11.

[0014] The second aspect of the present invention provides the application of the above method in scale prevention in industrial water pipelines or underground formation water environments of oil and water wells.

[0015] The method for preventing scale in hard water provided by the present invention adopts a biological scale inhibitor with a polyhydroxyl group, a cavity and a phosphate structure, and mixes the above scale inhibitor with hard water. The polynuclear hydroxyl group and the cage-like structure have a strong complexing and stable dispersion effect on scale-forming ions, thereby achieving the goal of a low concentration and high scale inhibition rate. 2+ , Ba 2+ , Sr 2+ The polyvalent metals have chelation and coating effects, and have excellent scale inhibition performance in complex and harsh water quality. The method has the advantages of good scale inhibition performance, no biological toxicity, colorless, and no special odor. Under optimal conditions, the method can obtain good scale inhibition effect at a lower dosage of scale inhibitor, and achieve the effect of low concentration and high scale inhibition rate.

[0016] The bio-friendly scale inhibitor provided by the present invention is suitable for the field of industrial water scale inhibition, especially for the field of scale inhibition of high-concentration cooling circulation pipelines (towers), water jacket heating furnaces, and high-hardness formation water environments in oil and water wells. The polynuclear hydroxyl group and the oxygen atoms in the molecule have strong electronegativity, interact with the metal atoms on the surface of the metal pipeline, adsorb on the metal surface, form a protective film, prevent the generated scale dust from accumulating on the metal surface to form a dense scale layer, and solve the problem that the scale salt accumulated on the pipeline surface is difficult to remove. DETAILED DESCRIPTION

[0017] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0018] In one aspect, the present invention provides a method for preventing scale in hard water, the method comprising: mixing a scale inhibitor with hard water; the scale inhibitor comprises a compound represented by formula (I),

[0019]

[0020] Wherein, in formula (I),

[0021] R1 is selected from C8-C 22 The alkyl group;

[0022] Each R2 is independently selected from H, 2-hydroxypropyl or methyl;

[0023] R3 and R4 are each independently selected from H, -PO3M2 or -PO3HM, and R3 and R4 are not H at the same time;

[0024] M is selected from any one of Li, Na, K, and NH4;

[0025] m is selected from any integer of 1-10, n is selected from any integer of 1-10, z is selected from any integer of 0-9, and the sum of m, n and z is any integer of 5-11.

[0026] In the present invention, "C8-C 22 "Alkyl" means an alkyl group having a total of 8 to 22 carbon atoms, including C8-C 22 Straight chain alkyl, C8-C 22The branched alkyl group may be, for example, a straight chain alkyl group or a branched alkyl group having a total number of carbon atoms of 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22. For example, it may be n-octyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl, and the like. 16 Alkyl, C 10 -C 14 The alkyl group has a similar explanation, except that the number of carbon atoms is different.

[0027] According to some preferred embodiments of the present invention, R1 is selected from C8-C 16 Preferably, R1 is selected from C 10 -C 14 More preferably, R1 is dodecyl, and more preferably n-dodecyl. Under the above preferred structural composition, it is beneficial to further improve the scale inhibition effect.

[0028] According to some preferred embodiments of the present invention, each R2 in formula (I) is independently selected from H or 2-hydroxypropyl.

[0029] According to some preferred embodiments of the present invention, R3 and R4 are each independently selected from H, -PO3M2 or -PO3HM, and R3 and R4 are not H at the same time.

[0030] According to some preferred embodiments of the present invention, M is selected from any one of Li, Na, K, and NH4.

[0031] According to some preferred embodiments of the present invention, m is selected from any integer of 1-7, n is selected from any integer of 1-7, z is selected from any integer of 0-6, and the sum of m, n and z is any integer of 6-8.

[0032] In a further preferred embodiment, the scale inhibitor comprises a compound as shown in formula (1) and / or formula (2),

[0033]

[0034] Wherein, R1 is selected from C 10 -C 14 The alkyl group is preferably -C 12 H 25 ;

[0035] M is selected from Na, K or NH4 + ;

[0036] m is selected from any integer of 1-7, n is selected from any integer of 1-7, z is selected from any integer of 0-6, and the sum of m, n and z is any integer of 6-8.

[0037] According to some preferred embodiments of the present invention, the above-mentioned scale inhibitor can be prepared by the method disclosed in Chinese patent application 202310007991.5, and the entire content of this patent application is cited in the present invention.

[0038] Preferably, the method for preparing the antiscalant comprises:

[0039] (1) in the presence of solvent I and a catalyst, subjecting the 1,2-epoxy compound represented by formula (I-1) and the cyclodextrin compound represented by formula (I-2) to a first contact reaction to obtain an intermediate;

[0040] (2) in the presence of solvent II, subjecting the intermediate to a phosphoesterification reaction with a phosphoesterification agent to obtain a mixture I;

[0041] (3) subjecting the mixture I to a hydrolysis reaction to obtain a mixture II;

[0042] (4) using an alkaline substance containing the element M to adjust the pH value of the mixture II to be greater than or equal to 7;

[0043]

[0044] In formula (I-1), formula (I-2), and alkaline substances,

[0045] The definitions of R1, R2, m, n, z, and M are the same as those in the first aspect.

[0046] It should be noted that the cyclodextrin compound represented by formula (I-2), the 1,2-epoxy compound represented by formula (I-1) and the phosphating agent in the present invention can be commercially available chemical reagents or can be prepared by those skilled in the art according to methods known in the art.

[0047] In the present invention, the method for preparing the cyclodextrin phosphate type surfactant is preferably carried out under stirring. There is no particular requirement for the stirring speed, and the stirring can be carried out using parameters known in the art.

[0048] According to a preferred embodiment, the method further comprises: in step (1), filtering and drying the product after the first contact reaction between the 1,2-epoxy compound and the cyclodextrin compound. The present invention does not particularly limit the filtering and drying methods, and those skilled in the art can perform the filtering and drying according to known methods; as long as an intermediate can be obtained after the solvent is removed and dried to a constant weight.

[0049] According to another preferred embodiment, in step (1), the cyclodextrin compound is provided by at least one of cyclodextrin, methyl cyclodextrin, hydroxyethyl cyclodextrin, and hydroxypropyl cyclodextrin.

[0050] Preferably, the cyclodextrin is selected from at least one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

[0051] More preferably, the cyclodextrin compound is at least one selected from α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and hydroxypropyl-β-cyclodextrin.

[0052] Preferably, in step (1), the molar ratio of the cyclodextrin compound to the 1,2-epoxy compound is 1:(1-40).

[0053] More preferably, the molar ratio of the cyclodextrin compound to the 1,2-epoxy compound is 1:(1-32).

[0054] Preferably, in step (1), the solvent I is water; the catalyst is an alkali metal hydroxide or 4-dimethylaminopyridine. In the present invention, there is no particular limitation on the water, which can be deionized water, tap water, etc.

[0055] Preferably, the alkali metal hydroxide is selected from at least one of NaOH, KOH and LiOH.

[0056] According to a preferred embodiment, in step (1), the conditions of the first contact reaction at least meet the following conditions: temperature of 30-100°C, time of 1-10 hours. More preferably, the conditions of the first contact reaction at least meet the following conditions: temperature of 60-90°C, time of 3-8 hours.

[0057] According to another preferred embodiment, in step (1), relative to 1 mmol of the cyclodextrin compound, the amount of the solvent I is 0.1-50 mL, and the amount of the catalyst is 0.001-0.1 mmol. More preferably, relative to 1 mmol of the cyclodextrin compound, the amount of water is 1-10 mL, and the amount of the catalyst is 0.005-0.1 mmol.

[0058] Preferably, in step (2), the phosphating agent is selected from at least one of polyphosphoric acid and phosphorus pentoxide.

[0059] Preferably, the mass ratio of the intermediate to the phosphating agent is 1:(0.5-15). More preferably, the mass ratio of the intermediate to the phosphating agent is 1:(2-5).

[0060] Preferably, relative to 1 g of the intermediate, the amount of the solvent II is 5-20 mL.

[0061] Preferably, in step (2), the solvent II is selected from at least one of tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0062] According to a preferred embodiment, in step (2), the conditions of the phosphoesterification reaction at least meet the following conditions: temperature of 60-120°C and time of 2-12 hours. More preferably, the conditions of the phosphoesterification reaction at least meet the following conditions: temperature of 60-120°C and time of 4-6 hours.

[0063] Preferably, in step (3), the conditions of the hydrolysis reaction at least meet the following conditions: temperature of 60-120°C and time of 0.5-6h. More preferably, the conditions of the hydrolysis reaction at least meet the following conditions: temperature of 60-120°C and time of 0.5-2h.

[0064] Preferably, in step (3), the amount of water used is 5-30 wt % based on the total mass of the intermediate and the phosphating agent.

[0065] Preferably, in step (4), the alkaline substance is selected from at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide and ammonia water.

[0066] In step (4) of the present invention, the alkaline substance is preferably added in the form of an aqueous solution, and the concentration of the aqueous solution of the alkaline substance is 0.1wt%-50wt%. More preferably, the concentration of the aqueous solution of the alkaline substance is 5wt%-15wt%.

[0067] Preferably, in step (4), an alkaline substance containing element M is used to adjust the pH value of the mixture II to 7-9.

[0068] Preferably, the method further comprises: removing the solvent from the product obtained in step (4) by rotary evaporation, and drying to obtain a cyclodextrin phosphate surfactant. The present invention has no particular limitation on the rotary evaporation and drying methods, and can be carried out using known technical means in the art.

[0069] The high-hardness water scale inhibition method provided by the present invention can be applied to any water system with scale ions in the art. The high-hardness water scale inhibition method provided by the present invention has a good scale inhibition effect on various ions such as Ca, Sr, Ba, etc. in high-hardness water, and is particularly suitable for scale inhibition in water environments with complex composition or large changes in water quality.

[0070] Preferably, the method provided by the present invention is particularly suitable for highly industrial circulating water and / or oilfield groundwater, such as highly concentrated industrial water or highly mineralized formation water in a wellbore and other complex water environments with large water quality changes. The method provided by the present invention has excellent scale inhibition effect for highly concentrated, high-hardness industrial water and highly mineralized oilfield formation water, while for the above-mentioned water environment, the scale inhibition effect of the scale inhibition system in the prior art, especially the phosphorus-free scale inhibition system, is limited, and usually requires the compounding of multiple components, and it is difficult to meet the increasingly stringent environmental protection requirements.

[0071] According to some preferred embodiments of the present invention, the mineralization of the high hardness water is 100-50000 mg / L, preferably 100-30000 mg / L, in terms of Ca ion concentration. In the present invention, the mineralization refers to the sum of carbonates, bicarbonates, chlorides, sulfates, nitrates and various sodium salts of metals such as calcium, magnesium, aluminum, strontium, barium and manganese in water, and the concentration of each metal is measured as the mass concentration of equimolar calcium ions.

[0072] The present invention has no particular requirements for the composition of the metal ions in the high-hardness water. For example, the water may contain calcium, magnesium, barium, strontium, potassium, sodium, etc.

[0073] According to the present invention, compared with the existing scale inhibition system, the high hardness water scale inhibition method provided by the present invention is more effective for water containing high Ba 2+ , Sr 2+ The water system with high concentration also has excellent scale inhibition effect. The reason may be that the scale inhibitor used in the method provided by the present invention has multiple hydroxyl, cavity and phosphate structures at the same time, which has chelating and coating effects on multivalent metals in the water body, thus having excellent scale inhibition performance in complex and harsh water quality.

[0074] According to some preferred embodiments of the present invention, the Ba in the high hardness water 2+ The concentration is 1-5000 mg / L, preferably 5-2000 mg / L.

[0075] According to some preferred embodiments of the present invention, Sr 2+ The concentration is 1-5000 mg / L, preferably 5-2000 mg / L.

[0076] The present invention has a wide range of selection for the dosage of the scale inhibitor, which can be selected according to actual needs. Preferably, based on 1L of the high hardness water, the dosage of the scale inhibitor is 2-1000mg, preferably 100-500mg. The above preferred embodiment can meet the needs of scale inhibition.

[0077] According to some preferred embodiments of the present invention, the mixing temperature is 0-120°C, preferably 20-80°C.

[0078] The second aspect of the present invention provides the application of the above method in scale prevention in industrial water pipelines or underground formation water environments of oil and water wells.

[0079] The present invention will be described in detail below through examples.

[0080] According to the standard SY / T5673-93 "Performance Evaluation Method of Scale Inhibitors for Oilfields", simulated high-hardness water was configured to test the scale inhibition effect.

[0081] The following examples are used to illustrate the scale inhibition effect of the scale inhibition method of the present invention on calcium carbonate.

[0082] Example 1

[0083] The scale inhibitor used was prepared according to Example 1 in patent application 202310007991.5 and was denoted as T1. T1 has a structure shown in formula (1), wherein R1 is n-dodecyl, m is 2, n is 1, z is 4, the sum of m, n, and z is 7, and M is Na.

[0084] 1) Prepare Ca 2+ 10g / L CaCl2 and 10g / L Na2CO3 solution;

[0085] 2) Accurately add 100 mL of the CaCl2 preparatory solution prepared in step 1) into a 250 mL volumetric flask, add a certain amount of bioscaling inhibitor, and then add 100 mL of the Na2CO3 preparatory solution, dilute to 250 mL with distilled water, the concentration of the bioscaling inhibitor is 300 mg / L, shake well, and place in a 90°C oven for 14 days, then take out and extract the supernatant. Test the Ca content in the supernatant according to the provisions of SY / T5523. 2+ Concentration C 阻 .

[0086] The scale inhibition rate was calculated according to formula (1). The experimental results are shown in Table 1.

[0087]

[0088] Among them, c 阻 Indicates the Ca content in the supernatant after adding bio-inhibitor 2+ concentration;

[0089] C0 represents the Ca content in the initial solution 2+ concentration;

[0090] C 未 Indicates the Ca content in the supernatant without adding scale inhibitor 2+ Concentration (blank control: according to the method of the embodiment, no bioscaling inhibitor was added, and the other steps were the same. After standing in a 90°C oven for 14 days, the Ca in the supernatant was taken out and measured.2+ Concentration C 未 ).

[0091] Example 2

[0092] The method of Example 1 is different in that the scale inhibitor used is prepared according to Example 2 in Patent Application 202310007991.5, and is recorded as T2. T2 has a structure shown in formula (2), wherein R1 is n-dodecyl, the sum of m, n, and z is 7, and according to the integrated area of ​​the 1H NMR spectrum, the average value of m is 2, the average value of n is 1, z is 4, and M is Na.

[0093] The scale inhibition rate of calcium carbonate was tested according to the method of Example 1. The results are shown in Table 1.

[0094] Example 3

[0095] The method of Example 1 is followed, except that the scale inhibitor used is prepared according to Example 3 in Patent Application 202310007991.5, and is denoted as T3. T3 has a structure shown in formula (1), wherein R1 is n-dodecyl, and according to the integrated area of ​​the 1H NMR spectrum, the average value of m is 2, n is 1, z is 3, the sum of m, n, and z is 6, and M is K.

[0096] The scale inhibition rate of calcium carbonate was tested according to the method of Example 1. The results are shown in Table 1.

[0097] Example 4

[0098] The method of Example 1 is followed, except that the scale inhibitor used is prepared according to Example 4 in Patent Application 202310007991.5, and is denoted as T4. T4 has a structure shown in formula (1), wherein R1 is n-dodecyl, m is 2, n is 2, z is 4, the sum of m, n, and z is 8, and M is K.

[0099] The scale inhibition rate of calcium carbonate was tested according to the method of Example 1. The results are shown in Table 1.

[0100] Comparative Example 1

[0101] The method of Example 1 is followed, except that the scale inhibitor used is PBTCA (2-phospho-1,2,4-tricarboxylic acid butane, commercially available)

[0102] The scale inhibition rate of calcium carbonate was tested according to the method of Example 1. The results are shown in Table 1.

[0103] The following examples are used to illustrate the scale inhibition effect of the scale inhibition method of the present invention on calcium sulfate.

[0104] Example 5

[0105] The scale inhibitor used was prepared according to Example 1 in patent application 202310007991.5 and was denoted as T1. T1 has a structure shown in formula (1), wherein R1 is n-dodecyl, m is 2, n is 1, z is 4, the sum of m, n, and z is 7, and M is Na.

[0106] 1) Prepare 20g / L CaCl2 solution and 20g / L Na2SO4 solution respectively.

[0107] 2) Accurately add 100mL of the CaCl2 preparatory solution prepared in step 1) to a 250mL volumetric flask, add antiscalant T1, and then add 100mL of the Na2SO4 preparatory solution, dilute to the mark with distilled water, shake well, and the concentration of antiscalant T1 is 500mg / L. After standing in a 90℃ oven for 14 days, take out and extract the supernatant. According to the provisions of SY / T5523, test the Ca content in the supernatant. 2+ Concentration C 阻 .

[0108] The scale inhibition rate was calculated according to formula (1). The experimental results are shown in Table 1.

[0109]

[0110] Among them, c 阻 Indicates the Ca content in the supernatant after adding bio-inhibitor 2+ concentration;

[0111] C0 represents the Ca content in the initial solution 2+ concentration;

[0112] C 未 Indicates the Ca content in the supernatant without adding scale inhibitor 2+ Concentration (blank control: according to the method of the embodiment, no bioscaling inhibitor was added, and the other steps were the same. After standing in a 90°C oven for 14 days, the Ca in the supernatant was taken out and measured. 2+ Concentration C 未 ).

[0113] Embodiment 6-8

[0114] The method of Example 5 is followed, except that the above-mentioned scale inhibitors T2, T3 and T4 are used to replace T1.

[0115] The scale inhibition rate of calcium sulfate was calculated and the results are shown in Table 1.

[0116] Comparative Example 2

[0117] The method of Example 5 was followed, except that the scale inhibitor used was PBTCA (2-phospho-1,2,4-tricarboxylic acid butane), denoted as D1.

[0118] The scale inhibition rate of calcium sulfate was tested according to the method of Example 5. The results are shown in Table 1.

[0119] Table 1

[0120]

[0121] The following examples are used to illustrate the scale inhibition effect of the scale inhibition method of the present invention on barium sulfate and strontium sulfate.

[0122] Example 9

[0123] 1) Prepare BaCl2 and Na2SO4 solutions with a concentration of 1 g / L respectively;

[0124] 2) Accurately add 100 mL of the BaCl2 preparatory solution prepared in step 1) into a 250 mL volumetric flask, add a certain amount of bioscaling inhibitor T1 and then add 100 mL of the Na2SO4 preparatory solution, dilute to the mark with distilled water, shake well, the concentration of the scale inhibitor is 300 mg / L, and place in a 90°C oven for 14 days, then take out and extract the supernatant. 2+ The ion concentration was measured by atomic absorption spectrophotometer, and the specific test parameters are shown in Table 2. The scale inhibition rate of barium sulfate was calculated, and the results are shown in Table 3.

[0125] Table 2

[0126] element light source Wavelength nm flame barium Barium cathode lamp 553.5 Acetylene-nitrous oxide strontium Strontium cathode lamp 461.5 Air-Acetylene

[0127] Examples 10-12

[0128] The method of Example 9 is followed, except that the above-mentioned scale inhibitors T2, T3 and T4 are used to replace T1.

[0129] The scale inhibition rate of barium sulfate was calculated and the results are shown in Table 3.

[0130] Comparative Example 3

[0131] The method of Example 9 was followed, except that the scale inhibitor used was PBTCA (2-phospho-1,2,4-tricarboxylic acid butane), denoted as D1.

[0132] The scale inhibition rate of barium sulfate was tested according to the method of Example 9. The results are shown in Table 3.

[0133] Example 13

[0134] 1) Prepare 1g / L SrCl2 and 1g / L Na2SO4 solutions respectively;

[0135] 2) Accurately add 100 mL of the SrCl2 preparatory solution prepared in step 1) into a 250 mL volumetric flask, add a certain amount of bioscaling inhibitor T1 and then add 100 mL of the Na2SO4 preparatory solution, dilute to the mark with distilled water, shake well, the concentration of the scale inhibitor is 300 mg / L, place in a 90°C oven for 14 days, take out, extract the supernatant, and Ba 2+ The ion concentration was measured by atomic absorption spectrophotometer, and the specific test parameters are shown in Table 2. The scale inhibition rate of barium sulfate was calculated, and the results are shown in Table 3.

[0136] Examples 14-16

[0137] The method of Example 13 is followed, except that the above-mentioned scale inhibitors T2, T3 and T4 are used to replace T1.

[0138] The scale inhibition rate of barium sulfate was calculated and the results are shown in Table 3.

[0139] Comparative Example 4

[0140] The method of Example 13 was followed, except that the scale inhibitor used was PBTCA (2-phospho-1,2,4-tricarboxylic acid butane), denoted as D1.

[0141] The scale inhibition rate of barium sulfate was tested according to the method of Example 13. The results are shown in Table 3.

[0142] Table 3

[0143]

[0144] Embodiment 17

[0145] The scale inhibition treatment of produced water from an oil well in the northwest block of Shengli was tested. The mineralization of the injected water is 25118 mg / L, of which K + \Na + The concentration is 6835mg / L, Ca 2+ The concentration is 7274mg / L, Mg 2+ The concentration of Ba is 642mg / L. 2+ The concentration of Sr is 331.2 mg / L. 2+ The concentration is 300.04 mg / L.

[0146] (1) Add 100 mL of produced water and a certain amount of scale inhibitors T1, T2, T3, T4 and D1 to the 250 mL volumetric flasks numbered 1-5.

[0147] (2) Add 100 mL of 20 g / L Na2SO4 preparatory solution to the mixed system in (1), add distilled water to make the volume 250 mL, shake well to make the concentration of scale inhibitor after addition to 500 mg / L, and place in a 90°C oven for 14 days.

[0148] (3) Test the Ca in the supernatant separately 2+ , Ba 2+ , Sr 2+ concentration.

[0149] (4) Blank test: In addition to not adding scale inhibitor, 100 mL of 20 g / L Na2SO4 preparatory solution was directly added to 100 mL of on-site produced water, and then the water was allowed to stand. The Ca content in the supernatant of the blank test without adding scale inhibitor was tested. 2+ , Ba 2+ , Sr 2+ concentration.

[0150] The calculated scale inhibition rate is shown in Table 4.

[0151] Table 4

[0152]

[0153] Combining the results of Tables 1 to 4, it can be seen that the scale inhibition method provided by the present invention, after mixing the scale inhibitor with simulated highly concentrated and hard water, the scale inhibition rate of calcium carbonate and calcium sulfate reaches more than 96%. Compared with the commonly used scale inhibitors on the market, the biological scale inhibitor of the present invention also has significant advantages over barium strontium scale, and the scale inhibition rate can reach more than 96%. The scale inhibitor disclosed in the present invention has excellent scale inhibition performance for highly concentrated circulating water, boiler water and high-hardness oil field groundwater, ensuring safe production.

[0154] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preventing scale in high hardness water, characterized in that: The method comprises: mixing a scale inhibitor with high hardness water; the scale inhibitor comprises a compound represented by formula (I), Wherein, in formula (I), R1 is selected from C8-C 22 The alkyl group; Each R2 is independently selected from H, 2-hydroxypropyl or methyl; R3 and R4 are each independently selected from H, -PO3M2 or -PO3HM, and R3 and R4 are not H at the same time; M is selected from any one of Li, Na, K, and NH4; m is selected from any integer of 1-10, n is selected from any integer of 1-10, z is selected from any integer of 0-9, and the sum of m, n and z is any integer of 5-11.

2. The method according to claim 1, wherein: In formula (I), R1 is selected from C8-C 16 and / or Each R2 is independently selected from H or 2-hydroxypropyl; and / or R3 and R4 are each independently selected from H, -PO3M2 or -PO3HM, and R3 and R4 are not H at the same time; and / or M is selected from any one of Li, Na, K, NH4; and / or m is selected from any integer of 1-7, n is selected from any integer of 1-7, z is selected from any integer of 0-6, and the sum of m, n and z is any integer of 6-8.

3. The method according to claim 1, wherein: The scale inhibitor includes a compound as shown in formula (1) and / or formula (2), Wherein, R1 is selected from C 10 -C 14 The alkyl group is preferably -C 12 H 25 ; M is selected from Na, K or NH4 + ; m is selected from any integer of 1-7, n is selected from any integer of 1-7, z is selected from any integer of 0-6, and the sum of m, n and z is any integer of 6-8.

4. The method according to any one of claims 1 to 3, wherein: The highly hard water is high-hardness industrial circulating water and / or oil field groundwater.

5. The method according to claim 4, wherein: Measured in terms of Ca ion concentration, the mineralization of the high hardness water is 100-50000 mg / L, preferably 100-30000 mg / L.

6. The method according to claim 4, wherein: The high hardness water 2+ The concentration is 1-5000 mg / L, preferably 5-2000 mg / L.

7. The method according to claim 4, wherein: The Sr in high hardness water 2+ The concentration is 1-5000 mg / L, preferably 5-2000 mg / L.

8. The method according to any one of claims 1 to 7, wherein: Based on 1L of the high hardness water, the dosage of the scale inhibitor is 2-1000mg, preferably 100-500mg.

9. The method according to any one of claims 1 to 8, wherein: The mixing temperature is 0-120°C, preferably 20-80°C.

10. Use of the method according to any one of claims 1 to 9 in scale prevention in industrial water pipelines or underground formation water environments of oil and water wells.

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