Methods and applications for scale inhibition in high-hardness water

Abstract

This invention relates to the field of industrial water treatment technology, and discloses a method for inhibiting scale in high-hardness water and its application. The method includes: mixing a scale inhibitor with high-hardness water; the scale inhibitor includes a compound having the formula (I), in which R1 is selected from C8-C9. 22 The alkyl group; 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 simultaneously H; M is selected from any one of Li, Na, K, and NH4; m is selected from any integer from 1 to 10, n is selected from any integer from 1 to 10, z is selected from any integer from 0 to 9, and the sum of m, n, and z is any integer from 5 to 11. This method has advantages such as being non-biotoxic, colorless, and odorless, and is suitable for Ca in complex water bodies. 2+ Ba 2+ 、Sr 2+ Isovalent metals have excellent scale inhibition effects.

Description

Technical Field

[0001] This invention relates to the field of industrial water treatment technology, specifically to a method for inhibiting scale formation in high-hardness water and its application. Background Technology

[0002] During long-term operation and concentration, industrial circulating water experiences increased concentrations of scale-forming ions. The precipitated scale salts deposit on pipelines and other equipment surfaces, affecting heat exchange efficiency, clogging pipelines, and causing under-deposit corrosion, posing serious safety hazards and economic losses to industrial production. Similarly, in oilfield production, inorganic scale, especially calcium sulfate, barium sulfate, and strontium sulfate, often clogs the near-wellbore area and wellbore, leading to downhole blockages, affecting oil and gas production, and even causing the abandonment of oil and water wells. Therefore, scale inhibitors play a crucial role in industrial and oilfield production.

[0003] Scale inhibitors primarily achieve scale inhibition through chelation, adsorption dispersion, and scale salt lattice distortion. Commercially available scale inhibitors are mainly used in low-hardness environments such as industrial circulating water. Polymer scale inhibitors possess advantages such as superior performance and good thermal stability. Synergistically with organophosphonates, they inhibit the precipitation of scale-forming ions and the formation of scale salts through complexation, and have become a research hotspot in water treatment agents. CN11621278A discloses a macrocyclic compound supramolecular scale solvent system. Although this scale solvent is effective against Ba... 2+ 、Sr 2+ While exhibiting excellent scale inhibition performance, its solubility is poor, requiring the addition of various additives such as co-solvents and complexing agents to ensure stable dispersion in water. Furthermore, this system is unsuitable for environments with significant water quality fluctuations. CN107522298A discloses a composite corrosion and scale inhibitor composed of a copolymer, carboxymethyl compounds, and cyclodextrin derivatives; this system is also unsuitable for harsh water environments with high hardness and high concentration. CN111960556A discloses a phosphorus-free scale inhibitor for high-hardness water, composed of a maleic anhydride-β-cyclodextrin-sodium p-styrene sulfonate copolymer, azole derivatives, zinc chloride, amino acid polymers, and additives. Although this scale inhibitor demonstrates good scale inhibition performance in high-hardness water, the system is complex, and the zinc salts and azole derivatives within it exhibit biotoxicity.

[0004] Existing scale inhibitors are typically used in cooling circulating water applications, which limits their applicability. They are ineffective in environments with high hardness and significant water quality fluctuations. Developing new, safe, environmentally friendly scale inhibitors with no toxic side effects on organisms is crucial to addressing the challenges of current phosphorus-free scale inhibitors in handling scale buildup in highly concentrated, high-hardness industrial water and oilfield wellbore scaling and clogging, as well as the difficulty in unclogging these conditions. Ensuring safe production and meeting increasingly stringent environmental requirements has become a new demand in scale inhibitor development. Summary of the Invention

[0005] The purpose of this invention is to overcome the limitations of existing technologies in inhibiting scale formation in highly concentrated, high-hardness industrial water, as well as their poor safety and environmental friendliness. Furthermore, the invention addresses a series of problems encountered in oilfield extraction, such as severe scaling in wellbore and near-wellbore areas caused by highly mineralized water, leading to pipeline blockage and difficulties in acid treatment and deblocking. The invention provides a method for inhibiting scale formation in high-hardness water and its application. This method can effectively suppress scaling in high-hardness water and has environmentally friendly advantages.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for inhibiting scale in high-hardness water, the method comprising: mixing a scale inhibitor with high-hardness water; the scale inhibitor comprising a compound having the formula (I).

[0007]

[0008] In equation (I),

[0009] R1 is selected from C8-C 22 Alkyl groups;

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

[0014] A second aspect of the present invention provides the application of the above method in scale inhibition in industrial water pipelines or oil-water well formation water environments.

[0015] The present invention provides a method for inhibiting scale formation in hard water. This method utilizes a biological scale inhibitor with a polyhydroxyl, cavity, and phosphate ester structure. The scale inhibitor is mixed with hard water. Its polynuclear hydroxyl groups and cage-like configuration exhibit strong complexing and stabilizing effects on scale-forming ions, achieving a high scale inhibition rate at low concentrations. This method also addresses the issue of calcium in the water. 2+ Ba 2+ 、Sr 2+ Isovalent metals possess chelating and coating properties, exhibiting excellent scale inhibition performance in complex and harsh water conditions. This method offers advantages such as good scale inhibition performance, non-biotoxicity, and being colorless and odorless. In preferred applications, this method can achieve good scale inhibition results with relatively low scale inhibitor dosages, realizing a high scale inhibition rate at low concentrations.

[0016] The bio-friendly scale inhibitor provided by this invention is suitable for scale inhibition in industrial water applications, especially for high-concentration cooling circulation pipelines (towers), water-jacketed heating furnaces, and high-hardness formation water environments in oil and water wells. The polynuclear hydroxyl groups and oxygen atoms in the molecule have strong electronegativity, interacting with metal atoms on the surface of metal pipelines, adsorbing onto the metal surface, and forming a protective film. This prevents the accumulation of scale and dust on the metal surface, forming a dense scale layer, thus solving the problem of difficult-to-remove scale salts accumulated on pipeline surfaces. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] This invention provides a method for inhibiting scale in high-hardness water, the method comprising: mixing a scale inhibitor with high-hardness water; the scale inhibitor comprising a compound having the formula (I),

[0019]

[0020] In equation (I),

[0021] R1 is selected from C8-C 22 Alkyl groups;

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

[0026] In this invention, "C8-C" 22 "alkyl" refers to an alkyl group with a total number of carbon atoms of 8-22, including C8-C6. 22 Straight-chain alkyl, C8-C 22Branched alkyl groups can be, for example, straight-chain or branched alkyl groups with a total number of carbon atoms of 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22. Examples include n-octyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, and n-hexadecyl. (For C8-C...) 16 alkyl, C 10 -C 14 Alkyl groups have 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 Alkyl group, preferably, R1 is selected from C 10 -C 14 The alkyl group, more preferably, R1 is dodecyl, and even more preferably n-dodecyl. Under the above-mentioned 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 both H.

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

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

[0033]

[0034] Among them, R1 is selected from C 10 -C 14 Alkyl groups, preferably -C 12 H 25 ;

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

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

[0037] According to some preferred embodiments of the present invention, the above-mentioned scale inhibitor can be produced by the method disclosed in Chinese Patent Application 202310007991.5, the entire contents of which are incorporated herein by reference.

[0038] Preferably, the method for preparing the scale inhibitor includes:

[0039] (1) In the presence of solvent I and catalyst, the 1,2-epoxide compound shown in formula (I-1) and the cyclodextrin compound shown in formula (I-2) are subjected to a first contact reaction to obtain an intermediate;

[0040] (2) In the presence of solvent II, the intermediate is subjected to a phosphoesterification reaction with a phosphoesterifying agent to obtain mixture I;

[0041] (3) Hydrolyze mixture I to obtain mixture II;

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

[0043]

[0044] In formulas (I-1), (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 compounds represented by formula (I-2), the 1,2-epoxide compounds represented by formula (I-1), and the phosphoesterifying agents in this 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 this invention, the method for preparing the cyclodextrin-based phosphate salt surfactant is preferably carried out under stirring. There are no special requirements for the stirring speed, and parameters known in the art can be used.

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

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

[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 selected from at least one of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and hydroxypropyl-β-cyclodextrin.

[0052] In a preferred embodiment, in step (1), the molar ratio of the cyclodextrin compound to the 1,2-epoxide compound is 1:(1-40).

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

[0054] In a preferred embodiment, in step (1), the solvent I is water; and the catalyst is an alkali metal hydroxide or 4-dimethylaminopyridine. The water used in this invention is not particularly limited and 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 for the first contact reaction are at least: a temperature of 30-100°C and a time of 1-10 hours. More preferably, the conditions for the first contact reaction are at least: a temperature of 60-90°C and a time of 3-8 hours.

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

[0058] In a preferred embodiment, in step (2), the phosphoesterifying agent is selected from at least one of polyphosphoric acid and phosphorus pentoxide.

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

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

[0061] In a preferred embodiment, in step (2), 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 for the phosphoesterification reaction are at least: a temperature of 60-120°C and a time of 2-12 hours. More preferably, the conditions for the phosphoesterification reaction are at least: a temperature of 60-120°C and a time of 4-6 hours.

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

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

[0065] In a preferred embodiment, 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 0.1 wt%-50 wt%. More preferably, the concentration of the aqueous solution of the alkaline substance is 5 wt%-15 wt%.

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

[0068] In a preferred embodiment, the method further includes: removing the solvent from the product obtained in step (4) by rotary evaporation and drying to obtain a cyclodextrin-based phosphate salt surfactant. The present invention does not particularly limit the methods of rotary evaporation and drying, and can employ known techniques in the art.

[0069] The method for inhibiting scale in hard water provided by this invention is applicable to any water system containing scale ions in the art. This method exhibits excellent scale inhibition effects on various ions such as Ca, Sr, and Ba in hard water, and is particularly suitable for scale inhibition in water environments with complex compositions or significant water quality variations.

[0070] In preferred embodiments, the method provided by this invention is particularly suitable for complex water environments with significant water quality fluctuations, such as highly concentrated industrial circulating water and / or oilfield groundwater, including highly concentrated industrial water or high-mineralized formation water in wellbores. The method provided by this invention exhibits excellent scale inhibition effects for highly concentrated, high-hardness industrial water and high-mineralized oilfield formation water. However, for the aforementioned water environments, existing scale inhibition systems, especially phosphorus-free scale inhibition systems, have limited scale inhibition effects, typically requiring multiple components and failing to meet increasingly stringent environmental protection requirements.

[0071] According to some preferred embodiments of the present invention, the mineralization of the high-hardness water, expressed as Ca ion concentration, is 100-50000 mg / L, preferably 100-30000 mg / L. In this 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 contained in the water, with the concentration of each metal expressed as the mass concentration of calcium ions in equimolar amounts.

[0072] The present invention does not have any special requirements for the composition of metal ions in the hard water, for example, it may contain calcium, magnesium, barium, strontium, potassium, sodium, etc.

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

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

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

[0076] The present invention provides a wide range of options for the dosage of the scale inhibitor, which can be selected according to actual needs. Preferably, based on 1L of high-hardness water, the dosage of the scale inhibitor is 2-1000mg, more preferably 100-500mg. By adopting the above-mentioned preferred embodiments, the scale inhibition requirements can be met.

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

[0078] A second aspect of the present invention provides the application of the above-described method in scale inhibition in industrial water pipelines or oil-water well formation water environments.

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

[0080] Referring to the standard SY / T5673-93 "Performance Evaluation Method of Scale Inhibitors for Oilfield Use", simulated high hard water was prepared to test the scale inhibition effect.

[0081] The following examples 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 is denoted as T1. T1 has the 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 separately 2+ A CaCl2 solution with a concentration of 10 g / L and a Na2CO3 solution with a concentration of 10 g / L;

[0085] 2) Accurately add 100 mL of the CaCl2 preparative solution prepared in step 1) to a 250 mL volumetric flask, add a certain amount of bioscale inhibitor, then add 100 mL of Na2CO3 preparative solution, dilute with distilled water to 250 mL (the concentration of the scale inhibitor is 300 mg / L), shake well, and let stand in a 90℃ oven for 14 days. Remove the flask, extract the supernatant, and test the Ca2+ concentration in the supernatant according to the specifications in SY / T5523. 2+ Concentration C 阻 .

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

[0087]

[0088] Among them, c 阻 This indicates the Ca content in the supernatant after adding a bioscale inhibitor. 2+ concentration;

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

[0090] C 未 This indicates the Ca content in the supernatant without scale inhibitor. 2+ Concentration (blank control: following the method of the example, without adding a bioscale inhibitor, with the other steps the same, after standing in a 90°C oven for 14 days, the Ca concentration in the supernatant was measured).2+ Concentration C 未 ).

[0091] Example 2

[0092] The method of Example 1 is followed, except that the scale inhibitor used is prepared according to Example 2 of patent application 202310007991.5 and is denoted as T2. T2 has the structure shown in formula (2), wherein R1 is n-dodecyl, the sum of m, n, and z is 7, and according to the integral 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 in Example 1, and 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 of patent application 202310007991.5 and is denoted as T3. T3 has the structure shown in formula (1), wherein R1 is n-dodecyl, and according to the integral 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 in Example 1, and 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 of patent application 202310007991.5 and is denoted as T4. T4 has the 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 in Example 1, and the results are shown in Table 1.

[0100] Comparative Example 1

[0101] The method is the same as in Example 1, except that the scale inhibitor used is PBTCA (2-phospho-1,2,4-tricarboxylate butane, commercially available).

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

[0103] The following examples 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 is denoted as T1. T1 has the 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 CaCl2 solution with a concentration of 20 g / L and Na2SO4 solution with a concentration of 20 g / L respectively.

[0107] 2) Accurately add 100 mL of the CaCl2 preparative solution prepared in step 1) to a 250 mL volumetric flask, add scale inhibitor T1, then add 100 mL of Na2SO4 preparative solution, dilute to the mark with distilled water, and shake well. The concentration of scale inhibitor T1 is 500 mg / L. After standing in a 90℃ oven for 14 days, remove the flask, extract the supernatant, and test the Ca2+ concentration in the supernatant according to the specifications in SY / T5523. 2+ Concentration C 阻 .

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

[0109]

[0110] Among them, c 阻 This indicates the Ca content in the supernatant after adding a bioscale inhibitor. 2+ concentration;

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

[0112] C 未 This indicates the Ca content in the supernatant without scale inhibitor. 2+ Concentration (blank control: following the method of the example, without adding a bioscale inhibitor, with the other steps the same, after standing in a 90°C oven for 14 days, the Ca concentration in the supernatant was measured). 2+ Concentration C 未 ).

[0113] Examples 6-8

[0114] The method is the same as in Example 5, except that T1 is replaced by the above-mentioned scale inhibitors T2, T3 and T4 respectively.

[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 is followed, except that the scale inhibitor used is PBTCA (2-phospho-1,2,4-tricarboxylate butane), denoted as D1.

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

[0119] Table 1

[0120]

[0121] The following examples 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 solutions with a concentration of 1 g / L and Na2SO4 solutions with a concentration of 1 g / L respectively;

[0124] 2) Accurately add 100 mL of the BaCl2 preparative solution prepared in step 1) to a 250 mL volumetric flask, add a certain amount of bioscale inhibitor T1, then add 100 mL of Na2SO4 preparative solution, dilute with distilled water to the mark, shake well, the concentration of the scale inhibitor is 300 mg / L, let stand in a 90℃ oven for 14 days, then remove, extract the supernatant, Ba... 2+ Ion concentrations were measured using an 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 is the same as in Example 9, except that T1 is replaced by the above-mentioned scale inhibitors T2, T3 and T4 respectively.

[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 is followed, except that the scale inhibitor used is PBTCA (2-phospho-1,2,4-tricarboxylate butane), denoted as D1.

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

[0133] Example 13

[0134] 1) Prepare SrCl2 solutions with a concentration of 1 g / L and Na2SO4 solutions with a concentration of 1 g / L respectively;

[0135] 2) Accurately add 100 mL of the SrCl2 preparative solution prepared in step 1) to a 250 mL volumetric flask, add a certain amount of bioscale inhibitor T1, then add 100 mL of Na2SO4 preparative solution, dilute with distilled water to the mark, shake well, the concentration of the scale inhibitor is 300 mg / L, let it stand in a 90℃ oven for 14 days, then take it out, extract the supernatant, Ba 2+ Ion concentrations were measured using an 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 is the same as in Example 13, except that T1 is replaced by the above-mentioned scale inhibitors T2, T3 and T4 respectively.

[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 is the same as in Example 13, except that the scale inhibitor used is PBTCA (2-phospho-1,2,4-tricarboxylate butane), denoted as D1.

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

[0142] Table 3

[0143]

[0144] Example 17

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

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

[0147] (2) Add 100 mL of 20 g / L Na2SO4 preparative solution to the mixture in (1), add distilled water to make up to 250 mL, shake well, so that the concentration of scale inhibitor after addition is 500 mg / L, and let stand in a 90℃ oven for 14 days.

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

[0149] (4) Blank test: Except for the absence of scale inhibitor, 100 mL of 20 g / L Na2SO4 preparative solution was added directly to 100 mL of field-collected water, and then allowed to stand. The Ca concentration in the supernatant of the blank test without scale inhibitor was then tested. 2+ Ba 2+ 、Sr 2+ concentration.

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

[0151] Table 4

[0152]

[0153] As shown in Tables 1-4, the scale inhibition method provided by this invention, after mixing the scale inhibitor with simulated highly concentrated and hard water, achieves a scale inhibition rate of over 96% for both calcium carbonate and calcium sulfate. Compared with commonly used scale inhibitors on the market, the biological scale inhibitor of this invention also has significant advantages for barium and strontium scale, with a scale inhibition rate of over 96%. The scale inhibitor disclosed in this invention exhibits excellent scale inhibition performance for highly concentrated circulating water, boiler water, and high-hardness oilfield groundwater, ensuring safe production.

[0154] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for inhibiting scale formation in high-hardness water, characterized in that, The method includes: mixing a scale inhibitor with hard water; the scale inhibitor comprising a compound having the formula (I), Formula (I), In equation (I), R1 is selected from C8-C 22 Alkyl groups; 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 both H at the same time; M is selected from any one of Li, Na, K, and NH4; m is selected from any integer from 1 to 10, n is selected from any integer from 1 to 10, z is selected from any integer from 0 to 9, and the sum of m, n, and z is any integer from 5 to 11.

2. The method according to claim 1, wherein, In equation (I), R1 is selected from C8-C 16 Alkyl groups; and / or Each R2 is independently selected from H or 2-hydroxypropyl; and / or m is selected from any integer from 1 to 7, n is selected from any integer from 1 to 7, z is selected from any integer from 0 to 6, and the sum of m, n, and z is any integer from 6 to 8.

3. The method according to claim 1, wherein, The scale inhibitor includes compounds as shown in formula (1) and / or formula (2), Equation (1), Equation (2), Among them, R1 is selected from C 10 -C 14 Alkyl groups; M is selected from Na, K, or NH4; m is selected from any integer from 1 to 7, n is selected from any integer from 1 to 7, z is selected from any integer from 0 to 6, and the sum of m, n, and z is any integer from 6 to 8.

4. The method according to claim 3, wherein, R1 is -C 12 H 25 .

5. The method according to any one of claims 1-4, wherein, The hard water is industrial circulating water and / or oilfield groundwater.

6. The method according to claim 5, wherein, The mineralization of the high-hardness water is 100-50000 mg / L, based on Ca ion concentration.

7. The method according to claim 6, wherein, The mineralization of the high-hardness water is 100-30000 mg / L, based on Ca ion concentration.

8. The method according to claim 5, wherein, Ba in the high hardness water 2+ The concentration is 1-5000 mg / L.

9. The method according to claim 8, wherein, Ba in the high hardness water 2+ The concentration is 5-2000 mg / L.

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

11. The method of claim 10, wherein, Sr in high hardness water 2+ The concentration is 5-2000 mg / L.

12. The method according to any one of claims 1-4, wherein, Based on 1L of the high-hardness water, the dosage of the scale inhibitor is 2-1000mg.

13. The method according to claim 12, wherein, Based on 1L of the high-hardness water, the dosage of the scale inhibitor is 100-500mg.

14. The method according to any one of claims 1-4, wherein, The mixing temperature is 0-120℃.

15. The method according to claim 14, wherein, The mixing temperature is 20-80℃.

16. The application of the method according to any one of claims 1-15 in scale inhibition in industrial water pipelines or oil-water well groundwater environments.

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