A multi-effect corrosion and scale inhibitor with scale and corrosion inhibition, and a preparation method and application thereof

Abstract

This application relates to the field of coalbed methane extraction reagents technology, and particularly to a multi-effect corrosion and scale inhibitor with both scale inhibition and corrosion inhibition functions, and its preparation method. The raw materials of the multi-effect corrosion and scale inhibitor, by weight, satisfy the following: thiourea derivative: 15-30 parts, polyacrylate metal salt: 5-10 parts, hydroxyasiatic acid: 5-10 parts, and water; wherein the thiourea derivative contains sulfur atoms, multiple nitrogen atoms, and multiple phosphate groups. This multi-effect corrosion and scale inhibitor improves its scale inhibition and corrosion inhibition properties through the synergistic effect of the thiourea derivative, polyacrylate metal salt, and hydroxyasiatic acid at the molecular level.

Description

Technical Field

[0001] This application relates to the field of coalbed methane extraction reagents technology, and in particular to a multi-effect corrosion and scale inhibitor with both scale inhibition and corrosion inhibition functions, and its preparation method. Background Technology

[0002] Produced water from deep coalbed methane wells has high salinity and generally contains dissolved corrosive gases such as carbon dioxide and oxygen. These corrosive gases easily cause corrosion and scaling in the pipelines used in the water injection system. As coalbed methane extraction time increases and water quality deteriorates, pipeline corrosion and scaling problems become increasingly severe, affecting normal well site production and causing significant economic losses. To mitigate corrosion and scaling in deep coalbed methane pipelines, corrosion inhibitors and scale inhibitors are typically added. However, single-component corrosion inhibitors and scale inhibitors may have compatibility issues during use, and adding these agents increases solvent consumption, leading to coalbed methane feedstock loss and further economic losses. Therefore, developing multi-effect corrosion and scale inhibitors with both scale inhibition and corrosion inhibition functions has become a current development trend.

[0003] Although multi-effect corrosion and scale inhibitors currently have good corrosion and scale inhibition properties, the test solutions used in the corrosion inhibition performance test have low mineralization, and these test solutions also ignore the severe corrosion of carbon steel by dissolved oxygen.

[0004] Existing technologies for multi-functional corrosion and scale inhibitors that combine scale inhibition and corrosion inhibition functions include: (1) a corrosion and scale inhibitor for oilfield water injection systems and its preparation method. This corrosion and scale inhibitor uses maleic anhydride, acrylic acid, and diethylenetriamine as raw materials. Maleic anhydride, acrylic acid, and diethylenetriamine are mixed in a weight ratio of (15-20):(10-20):(10-20), and a redox initiator is used to carry out a polymerization reaction to synthesize a maleic anhydride / acrylic acid / diethylenetriamine copolymer. This corrosion and scale inhibitor can simultaneously alleviate complex scaling such as CaCO3 scale, CaSO4 scale, and BaSO4 scale by chelating and dispersing scale-forming ions. (2) Neutral environmentally friendly corrosion and scale inhibitor for oilfield water injection systems and its preparation method. The raw materials of the neutral environmentally friendly corrosion and scale inhibitor are composed of 20-25 parts sodium iminodisuccinate, 6-10 parts sodium diethylenetriaminepentamethylphosphonate, 5-8 parts sodium citrate, 10-15 parts imidazoline, 2-5 parts thiourea, 2-5 parts polyethylene glycol, and 30-35 parts tap water. The corrosion and scale inhibitor has both scale inhibition and corrosion inhibition effects. Summary of the Invention

[0005] This application provides a multi-effect corrosion and scale inhibitor with both scale inhibition and corrosion inhibition functions, and its preparation method, to solve the following technical problem: how to improve the scale inhibition and corrosion inhibition effects of corrosion and scale inhibitors under conditions of high salinity and high dissolved oxygen content in produced water.

[0006] In a first aspect, this application provides a multi-effect corrosion and scale inhibitor that combines scale inhibition and corrosion inhibition functions, wherein, by weight, the raw materials of the multi-effect corrosion and scale inhibitor satisfy the following:

[0007] Thiourea derivative: 15 to 30 parts, polyacrylate metal salt: 5 to 10 parts, hydroxyasiatic acid: 5 to 10 parts, and water; wherein the thiourea derivative contains sulfur atoms, multiple nitrogen atoms, and multiple phosphate groups.

[0008] Optionally, the thiourea derivative has a molecular structure as shown in Formula 1.

[0009]

[0010] Optionally, the molecular weight of the polyacrylate is 1000 to 5000.

[0011] Optionally, the polyacrylate metal salt includes sodium polyacrylate and / or ammonium polyacrylate.

[0012] Optionally, the raw materials for the multi-effect corrosion and scale inhibitor also meet the following requirements: 1,2,4-triazole: 10 to 15 parts.

[0013] Secondly, this application provides a method for preparing the multi-effect corrosion and scale inhibitor described in the first aspect, the method comprising:

[0014] Preparation of thiourea derivatives;

[0015] A multi-effect corrosion and scale inhibitor is obtained by mixing polyacrylate metal salt, hydroxyasiatic acid, 1,2,4-triazole and the thiourea derivative.

[0016] Optionally, the preparation of the thiourea derivative includes the following steps:

[0017] Thiourea, phosphorous acid, paraformaldehyde, and hydrochloric acid are mixed to obtain a mixed raw material;

[0018] The mixed raw materials are subjected to a polymerization reaction to obtain a crude intermediate;

[0019] The crude intermediate was purified to obtain the intermediate.

[0020] The alkaline solution and the intermediate are neutralized to obtain a mixture of neutral intermediates;

[0021] The neutral intermediate mixture was distilled and dried to obtain a thiourea derivative.

[0022] The intermediate has a molecular structure as shown in Formula 2.

[0023]

[0024] Optionally, the amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the relationship: n1:n2:n3:n4 = 1:(4-6):(6-8):(2-4); and / or

[0025] The amount of substance n5 of the alkaline solution and the amount of substance n6 of the intermediate satisfy the following relationship: n5:n6=(4~8):1.

[0026] Optionally, the polymerization reaction temperature is 110℃~120℃, and the polymerization reaction time is 3.0h~4.0h.

[0027] Thirdly, this application provides a dual-effect reagent with corrosion and scale inhibition, the dual-effect reagent comprising the multi-effect corrosion and scale inhibitor described in the first aspect, wherein the weight m1 of the multi-effect corrosion and scale inhibitor and the volume V1 of the dual-effect reagent satisfy the relationship: m1:V1=(30~60):1000, and if the unit of m1 is g, then the unit of V1 is L.

[0028] The technical solutions provided in this application have the following advantages compared with the prior art:

[0029] This application provides a multi-effect corrosion and scale inhibitor with both scale inhibition and corrosion inhibition functions. This multi-effect corrosion and scale inhibitor uses a thiourea derivative containing sulfur atoms, multiple nitrogen atoms, and multiple phosphate groups as its main functional material. Based on the strong chelating properties of phosphate groups to form scale ions, it can inhibit the formation of calcium carbonate and barium sulfate scale in the produced water, thereby improving the scale inhibition performance of the multi-effect corrosion and scale inhibitor. In addition, nitrogen and sulfur atoms can adsorb more active metal ions in the produced water, thus preventing these active metal ions from corroding the pipeline and improving the corrosion inhibition effect of the multi-effect corrosion and scale inhibitor. Furthermore, the addition of polyacrylic acid metal salt can ensure that the multi-effect corrosion and scale inhibitor has a sufficient amount of carboxylate anions. On the one hand, sufficient carboxylate anions can adsorb on the surface of calcium carbonate and other scale in the produced water, and the electrostatic repulsion of the carboxylate anions promotes the dispersion of these calcium carbonate scale particles in the produced water, preventing the aggregation and deposition of these calcium carbonate scale particles. On the other hand… Sufficient carboxylate anions can insert into the mineral lattice of these calcium carbonate scales, causing lattice distortion and thus organizing the formation of these scales, thereby further improving the scale inhibition performance of the multi-effect corrosion and scale inhibitor. Furthermore, the addition of hydroxyasiatic acid ensures the multi-effect corrosion and scale inhibitor has sufficient hydroxyl groups. Based on the strong reducing properties of hydroxyl groups, combined with the phosphate groups, nitrogen and sulfur atoms of the thiourea derivative polyacrylate metal salt and the carboxylate anions of the polyacrylate metal salt, sufficient hydroxyl groups undergo an oxidation-reduction reaction with dissolved oxygen in the produced water, reducing the dissolved oxygen content and thus enhancing the corrosion inhibition effect of the multi-effect corrosion and scale inhibitor. Therefore, this multi-effect corrosion and scale inhibitor, through the synergistic effect of thiourea derivatives, polyacrylate metal salts, and hydroxyasiatic acid at the molecular level, improves its scale inhibition and corrosion inhibition performance, thereby enhancing its scale inhibition and corrosion inhibition effects even in produced water with high mineralization and high dissolved oxygen content. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic flowchart of a method for preparing a multi-effect corrosion and scale inhibitor provided in an embodiment of this application;

[0033] Figure 2This application provides a detailed flowchart illustrating a method for preparing a multi-effect corrosion and scale inhibitor.

[0034] Figure 3 This is a schematic diagram illustrating the polymerization reaction process of the method for preparing a multi-effect corrosion and scale inhibitor provided in the embodiments of this application. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range; in addition, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0037] In this document, terms such as “comprising” mean “including but not limited to”. Relational terms such as “first” and “second” are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. “And / or” describes the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can mean: A alone, A and B simultaneously, or B alone; where A and B can be singular or plural. “At least one” means one or more, “more” means two or more; “at least one,” “at least one of the following,” or similar expressions refer to any combination of these items, including any combination of single or plural items; for example, “at least one of a, b, or c,” or “at least one of a, b, and c,” can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. "Parts representation" such as parts by weight or parts by mass indicates the proportional relationship between components. In the proportional relationships discussed in this article, the parameters that need to be described by proportion should be understood as the first term of the proportion in the order of description, and the proportion figures should be understood as the second term of the proportion. For example, if the mass ratio of substance A, substance B, and substance C is 1:2:3, then substances A, B, and C should correspond one-to-one with the proportion figures in the proportion in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0038] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0039] It should be noted that, regarding the prior art (1) and prior art (2) described in the background art, the inventors found in actual experiments that the test solutions used in the corrosion inhibition performance test of these multi-effect corrosion and scale inhibitors have low mineralization, and these test solutions also ignore the severe corrosion of carbon steel by dissolved oxygen, making it difficult to cope with the actual high mineralization and high dissolved oxygen content of the produced water, thereby affecting the corrosion inhibition and scale inhibition performance of these multi-effect corrosion and scale inhibitors.

[0040] This application provides a multi-effect corrosion and scale inhibitor that combines scale inhibition and corrosion inhibition functions. The raw materials of the multi-effect corrosion and scale inhibitor, by weight, satisfy the following:

[0041] Thiourea derivative: 15 to 30 parts, polyacrylate metal salt: 5 to 10 parts, hydroxyasiatic acid: 5 to 10 parts, and water; wherein the thiourea derivative contains sulfur atoms, multiple nitrogen atoms, and multiple phosphate groups.

[0042] It should be noted that the mass fraction of the thiourea derivative can be 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 parts.

[0043] The mass fraction of the polyacrylate metal salt can be 5, 6, 7, 8, 9, or 10 parts.

[0044] The mass fraction of the hydroxyasiatic acid can be 5, 6, 7, 8, 9 or 10 parts.

[0045] Water, as a solvent and diluent, plays a crucial role in multi-effect corrosion and scale inhibitors. It helps to uniformly mix various raw materials, forming a stable solution and facilitating its addition to the required water treatment system. There are no special requirements regarding the mass fraction of water; it can be prepared according to actual needs.

[0046] In summary, the embodiments of this application provide a multi-effect corrosion and scale inhibitor that combines scale inhibition and corrosion inhibition functions. This multi-effect corrosion and scale inhibitor uses a thiourea derivative as its core functional component. This thiourea derivative not only contains sulfur atoms but is also rich in multiple nitrogen atoms and phosphate groups, giving the corrosion and scale inhibitor multiple functions. A detailed analysis follows:

[0047] First, the phosphate groups of thiourea derivatives are fully utilized due to their strong chelating ability. These phosphate groups can effectively combine with scale-forming ions such as calcium and barium ions in produced water to form stable water-soluble complexes, thereby preventing the deposition and scaling of sparingly soluble salts such as calcium carbonate and barium sulfate in the produced water treatment system. Based on this characteristic, the scale inhibition performance of multi-effect corrosion and scale inhibitors is significantly improved, ensuring the long-term stable operation of the produced water treatment system.

[0048] Secondly, the nitrogen and sulfur atoms of thiourea derivatives exhibit a strong adsorption capacity for reactive metal ions in produced water. These reactive metal ions, such as iron and copper ions, if left uncontrolled, readily react with oxygen or chloride ions in the produced water to form highly corrosive substances, thereby damaging the produced water treatment system. Through the adsorption effect of the nitrogen and sulfur atoms of thiourea derivatives, these reactive metal ions are effectively stabilized, thus significantly reducing the corrosion risk of the system and enhancing the corrosion inhibition effect of the multi-effect corrosion and scale inhibitor.

[0049] Furthermore, to further enhance the performance of the corrosion and scale inhibitor, this application embodiment also incorporates a metal salt of polyacrylate into the multi-effect corrosion and scale inhibitor. The introduction of the metal salt of polyacrylate not only increases the number of carboxylate anions in the corrosion and scale inhibitor, but these carboxylate anions can also effectively adsorb onto the surface of scale such as calcium carbonate. Through electrostatic repulsion, these carboxylate anions can promote the dispersion of calcium carbonate scale particles in the produced water, preventing their aggregation and deposition. Simultaneously, some carboxylate anions can also insert into the mineral lattice of the calcium carbonate scale, causing lattice distortion, thereby further inhibiting the formation and growth of scale in the produced water.

[0050] Finally, to comprehensively improve the performance of the corrosion and scale inhibitor, this application innovatively introduces hydroxyasiatic acid. The addition of hydroxyasiatic acid provides the corrosion and scale inhibitor with a large number of hydroxyl groups. These hydroxyl groups, due to their strong reducing properties, can undergo redox reactions with dissolved oxygen in the produced water, thereby effectively reducing the dissolved oxygen content. The reduction in dissolved oxygen directly inhibits the occurrence and development of corrosion reactions, further enhancing the corrosion inhibition effect of the corrosion and scale inhibitor.

[0051] In summary, the embodiments of this application provide a multi-effect corrosion and scale inhibitor that combines scale inhibition and corrosion inhibition. This multi-effect corrosion and scale inhibitor achieves a dual improvement in scale inhibition performance and corrosion inhibition through the synergistic effect of thiourea derivatives, polyacrylate metal salts, and hydroxyasiatic acid at the molecular level. This multi-effect corrosion and scale inhibitor is particularly suitable for the treatment of produced water with high salinity and high dissolved oxygen content, and can significantly improve the scale inhibition and corrosion inhibition effects under these harsh conditions.

[0052] In some alternative embodiments, the thiourea derivative has a molecular structure as shown in Formula 1.

[0053]

[0054]

[0055] In these embodiments, the thiourea derivative can have a molecular structure as shown in Formula 1, which enables the thiourea derivative to have sufficient sulfur atoms, nitrogen atoms and phosphate groups as the main functional material. The sufficient phosphate groups can inhibit the formation of calcium carbonate scale and barium sulfate scale in the produced water, thereby improving the scale inhibition performance of the multi-effect corrosion and scale inhibitor. In addition, the sufficient nitrogen atoms and sulfur atoms can adsorb more active metal ions in the produced water, thereby avoiding the corrosion of the pipeline by these active metal ions, so as to improve the corrosion inhibition effect of the multi-effect corrosion and scale inhibitor.

[0056] In some alternative embodiments, the molecular weight of the polyacrylate is 1000 to 5000;

[0057] In these embodiments, the molecular weight of polyacrylate can be 1000-5000, resulting in a lower molecular weight of polyacrylate. This allows the multi-effect corrosion and scale inhibitor to have a sufficient amount of carboxylate anions. On the one hand, the sufficient amount of carboxylate anions can adsorb onto the surface of scale such as calcium carbonate in the produced water, and through the electrostatic repulsion of the carboxylate anions, promote the dispersion of these calcium carbonate scale particles in the produced water, thereby preventing the aggregation and deposition of these calcium carbonate scale particles. On the other hand, the sufficient amount of carboxylate anions can insert into the mineral lattice of these calcium carbonate scale particles, causing the lattice of these calcium carbonate scale particles to become distorted, thereby preventing the formation of these calcium carbonate scale particles and further improving the scale inhibition performance of the multi-effect corrosion and scale inhibitor.

[0058] The molecular weight of the polyacrylate can be 1000, 2000, 3000, 4000 or 5000.

[0059] In some alternative embodiments, the polyacrylate metal salt comprises sodium polyacrylate and / or ammonium polyacrylate;

[0060] In these embodiments, the polyacrylate metal salt may include sodium polyacrylate and / or ammonium polyacrylate, which promotes the polyacrylate metal salt to have a sufficient amount of carboxylate anions. On the one hand, the sufficient amount of carboxylate anions can be adsorbed on the surface of scale such as calcium carbonate in the produced water, and the electrostatic repulsion of the carboxylate anions can promote the dispersion of these calcium carbonate scale particles in the produced water, thereby preventing the aggregation and deposition of these calcium carbonate scales. On the other hand, the sufficient amount of carboxylate anions can insert into the mineral lattice of these calcium carbonate scales and cause the lattice of these calcium carbonate scales to be distorted, thereby preventing the formation of these calcium carbonate scales and further improving the scale inhibition performance of the multi-effect corrosion and scale inhibitor.

[0061] In some optional embodiments, the raw materials of the multi-effect corrosion and scale inhibitor also meet the following requirements: 1,2,4-triazole: 10 parts to 15 parts;

[0062] In these embodiments, the raw materials for the multi-effect corrosion and scale inhibitor may also meet the following requirements: 1,2,4-triazole: 10 to 15 parts, which promotes the multi-effect corrosion and scale inhibitor to have sufficient cyclic structure and nitrogen atoms. Sufficient cyclic structure and nitrogen atoms can form strong chemical adsorption with the surface of metal ions in the produced water. In addition, triazole can form stable complexes with polyvalent ions (such as chloride ions) in the produced water. These complexes form a protective film on the surface of metal ions to further slow down the corrosion of metal ions in the produced water.

[0063] The mass fractions of 1,2,4-triazole can be 10, 11, 12, 13, 14, or 15 parts.

[0064] It should be noted that the corrosion inhibition performance of triazole mainly benefits from its strong bonding force with metal surfaces and its ability to form complexes with multivalent ions in water. These properties work together to form a protective layer on the surface of metal ions in the extracted water, thereby significantly slowing down the corrosion rate of the metal.

[0065] Figure 1 An exemplary schematic diagram of a method for preparing a multi-effect corrosion and scale inhibitor according to an embodiment of this application is shown;

[0066] Based on a general inventive concept, such as Figure 1 As shown in the embodiments of this application, a method for preparing the multi-effect corrosion and scale inhibitor is provided, the method comprising:

[0067] S1. Preparation of thiourea derivatives;

[0068] S2. Mix the polyacrylate metal salt, hydroxyasiatic acid, 1,2,4-triazole and the thiourea derivative to obtain a multi-effect corrosion and scale inhibitor.

[0069] This method is for the preparation of the above-mentioned multi-effect corrosion and scale inhibitor. The specific composition of the multi-effect corrosion and scale inhibitor can be referred to the above embodiments. Since this method adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0070] It should be noted that this mixing can be done in a mixer.

[0071] Figure 2 A detailed flowchart illustrating a method for preparing a multi-effect corrosion and scale inhibitor according to an embodiment of this application is shown by way of example.

[0072] Figure 3 A schematic diagram illustrating the polymerization reaction process of the method for preparing a multi-effect corrosion and scale inhibitor provided in this application is shown as an example.

[0073] In some alternative implementations, such as Figure 2 As shown, the preparation of the thiourea derivative includes the following steps:

[0074] S101. Mix thiourea, phosphorous acid, paraformaldehyde and hydrochloric acid to obtain a mixed raw material;

[0075] S102. The mixed raw materials are subjected to a polymerization reaction to obtain a crude intermediate;

[0076] S103. The crude intermediate is purified to obtain the intermediate;

[0077] S104. The alkaline solution and the intermediate are subjected to a neutralization reaction to obtain a mixture of neutral intermediates;

[0078] S105. The neutral intermediate mixture is distilled and dried to obtain a thiourea derivative;

[0079] The intermediate has a molecular structure as shown in Formula 2.

[0080]

[0081] In these embodiments, thiourea, phosphorous acid, paraformaldehyde, and hydrochloric acid are used as raw materials, and the mixture is processed as follows: Figure 3 The polymerization process and purification treatment shown can yield a pure intermediate with the structure shown in Formula 2. Then, under the action of an alkaline solution (sodium hydroxide), a neutralization reaction occurs between the intermediate and the alkaline component of the alkaline solution, thereby obtaining a thiourea derivative with the molecular structure shown in Formula 1.

[0082] It should be noted that the purification process may include cooling, filtration, and solid drying. The intermediate of the crude intermediate is precipitated by cooling, the intermediate is solidified by filtration, and finally the water in the intermediate solid phase is removed by solid drying, thereby obtaining a pure intermediate.

[0083] It should be noted that the alkaline solution can be a sodium hydroxide solution.

[0084] In some optional embodiments, the amounts of the thiourea (n1), the phosphorous acid (n2), the paraformaldehyde (n3), and the hydrochloric acid (n4) satisfy the relationship: n1:n2:n3:n4 = 1:(4-6):(6-8):(2-4); and / or

[0085] The amount of substance n5 of the alkaline solution and the amount of substance n6 of the intermediate satisfy the following relationship: n5:n6=(4~8):1;

[0086] In these embodiments, the amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the relationship: n1:n2:n3:n4 = 1:(4-6):(6-8):(2-4), ensuring that the mixed raw materials have sufficient amounts of thiourea, phosphorous acid, paraformaldehyde, and hydrochloric acid, thereby obtaining a sufficient amount of crude intermediate through subsequent polymerization. In addition, the amounts of alkaline solution (n5) and intermediate (n6) satisfy the relationship: n5:n6 = (4-8):1, ensuring that the intermediate has a sufficient amount of alkaline solution, so that the neutralization reaction stage can be carried out fully, thereby obtaining a sufficient amount of neutral intermediate mixture.

[0087] The amount of phosphorous acid, n2, can be 4, 5, or 6.

[0088] The amount of paraformaldehyde, n3, can be 6, 7, or 8.

[0089] The amount of hydrochloric acid, n4, can be 2, 3, or 4.

[0090] The amount of substance n5 of the alkaline solution can be 4, 5, 6, 7 or 8.

[0091] In some optional embodiments, the polymerization reaction is carried out at a temperature of 110°C to 120°C for a duration of 3.0 h to 4.0 h.

[0092] In these embodiments, the polymerization temperature can be 110°C to 120°C, and the polymerization time can be 3.0h to 4.0h, to promote the polymerization reaction to proceed fully so that the thiourea, phosphorous acid, paraformaldehyde and hydrochloric acid of the mixed raw materials can react fully, thereby obtaining a sufficient amount of crude intermediate.

[0093] The polymerization reaction temperature can be 110℃, 111℃, 112℃, 113℃, 114℃, 115℃, 116℃, 117℃, 118℃, 119℃ or 120℃.

[0094] The polymerization reaction can take 3.0h, 3.1h, 3.2h, 3.3h, 3.4h, 3.5h, 3.6h, 3.7h, 3.8h, 3.9h, or 4.0h.

[0095] Based on a general inventive concept, embodiments of this application provide a dual-effect reagent with corrosion and scale inhibition, the dual-effect reagent comprising the multi-effect corrosion and scale inhibitor, wherein the weight m1 of the multi-effect corrosion and scale inhibitor and the volume V1 of the dual-effect reagent satisfy the relationship: m1:V1=(30~60):1000, and if the unit of m1 is g, then the unit of V1 is L.

[0096] This dual-effect reagent is based on the above-mentioned multi-effect corrosion and scale inhibitor. The specific composition of the multi-effect corrosion and scale inhibitor can be referred to the above embodiments. Since this dual-effect reagent adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0097] It should be noted that the weight m1 of the multi-effect corrosion and scale inhibitor and the volume V1 of the dual-effect reagent can satisfy the following relationship:

[0098] m1:V1=(30~60):1000, which ensures that the dual-effect reagent has a sufficient amount of multi-effect corrosion and scale inhibitor, so as to facilitate the dual-effect reagent to improve the scale inhibition and corrosion inhibition effect of the corrosion inhibitor in produced water with high mineralization and high dissolved oxygen content.

[0099] The weight m1 of this multi-effect corrosion and scale inhibitor can be 30, 35, 40, 45, 50, 55 or 60.

[0100] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0101] Example 1

[0102] A multi-effect corrosion and scale inhibitor with both scale inhibition and corrosion inhibition functions, wherein the raw materials of the multi-effect corrosion and scale inhibitor, by mass fraction, satisfy the following:

[0103] Thiourea derivative: 15%, polyacrylate metal salt: 10%, hydroxyasiatic acid: 10%, and water: 55%; wherein the thiourea derivative contains sulfur atoms, multiple nitrogen atoms and multiple phosphate groups.

[0104] Thiourea derivatives have the molecular structure shown in Formula 1.

[0105]

[0106] The molecular weight of polyacrylate is 1000.

[0107] The metal salt of polyacrylate is sodium polyacrylate.

[0108] The raw materials for the multi-effect corrosion and scale inhibitor also meet the following requirements: 1,2,4-triazole: 10%.

[0109] like Figure 2 As shown, a method for preparing a multi-effect corrosion and scale inhibitor includes:

[0110] S101. Mix 1 mol of thiourea, 4 mol of phosphorous acid, 6 mol of paraformaldehyde and 4 mol of hydrochloric acid in 200g of water to obtain a mixed raw material;

[0111] S102. The mixed raw materials are subjected to a polymerization reaction to obtain a crude intermediate;

[0112] S103. Purify the crude intermediate to obtain the intermediate;

[0113] S104. Mix 4 mol of sodium hydroxide and 0.5 mol of the intermediate in 100 g of water to obtain a neutral intermediate mixture;

[0114] S105. Distill and dry the mixture of neutral intermediates to obtain a thiourea derivative;

[0115] The intermediate has a molecular structure as shown in Formula 2.

[0116]

[0117] S2. Mix the polyacrylate metal salt, hydroxyasiatic acid, 1,2,4-triazole and the thiourea derivative to obtain a multi-effect corrosion and scale inhibitor.

[0118] The amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the following relationship: n1:n2:n3:n4 = 1:4:6:4.

[0119] The amount of alkaline solution n5 and the amount of intermediate n6 satisfy the relationship: n5:n6=8:1.

[0120] The polymerization reaction was carried out at a temperature of 110℃ for 3.0 h.

[0121] Example 2

[0122] Based on the content disclosed in Example 1, the following modifications are made:

[0123] By mass fraction, the raw materials for the multi-effect corrosion and scale inhibitor meet the following requirements:

[0124] Thiourea derivative: 20%, polyacrylate metal salt: 5%, hydroxyasiatic acid: 10%, 1,2,4-triazole: 10%, and water: 55%.

[0125] The molecular weight of polyacrylate is 2100.

[0126] The amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the following relationship: n1:n2:n3:n4 = 1:4:8:2.

[0127] The amount of alkaline solution n5 and the amount of intermediate n6 satisfy the relationship: n5:n6=8:1.

[0128] The polymerization reaction was carried out at a temperature of 110℃ for 3.0 h.

[0129] Example 3

[0130] Based on the content disclosed in Example 1, the following modifications are made:

[0131] By mass fraction, the raw materials for the multi-effect corrosion and scale inhibitor meet the following requirements:

[0132] Thiourea derivative: 30%, polyacrylate metal salt: 5%, hydroxyasiatic acid: 5%, 1,2,4-triazole: 15%, and water: 45%.

[0133] The molecular weight of polyacrylate is 3000-5000.

[0134] The amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the following relationship: n1:n2:n3:n4 = 1:6:8:4.

[0135] The amount of alkaline solution n5 and the amount of intermediate n6 satisfy the relationship: n5:n6 = 4:1.

[0136] The polymerization reaction was carried out at a temperature of 110℃ for 3.0 h.

[0137] Example 4

[0138] Based on the content disclosed in Example 1, the following modifications are made:

[0139] By mass fraction, the raw materials for the multi-effect corrosion and scale inhibitor meet the following requirements:

[0140] Thiourea derivative: 20%, polyacrylate metal salt: 10%, hydroxyasiatic acid: 8%, 1,2,4-triazole: 12%, and water.

[0141] The molecular weight of polyacrylate is 4000-5000.

[0142] The amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the following relationship: n1:n2:n3:n4 = 1:5:6:3.

[0143] The amount of alkaline solution n5 and the amount of intermediate n6 satisfy the relationship: n5:n6=6:1.

[0144] The polymerization reaction was carried out at a temperature of 120℃ for 4.0 h.

[0145] Example 5

[0146] Based on the content disclosed in Example 1, the following modifications are made:

[0147] By mass fraction, the raw materials for the multi-effect corrosion and scale inhibitor meet the following requirements:

[0148] Thiourea derivative: 25%, polyacrylate metal salt: 8%, hydroxyasiatic acid: 5%, 1,2,4-triazole: 15%, and water: 47%.

[0149] The molecular weight of polyacrylate is 1000.

[0150] The amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the following relationship: n1:n2:n3:n4 = 1:4:6:2.

[0151] The amount of alkaline solution n5 and the amount of intermediate n6 satisfy the relationship: n5:n6=5:1.

[0152] The polymerization reaction was carried out at a temperature of 120℃ for 3.0 h.

[0153] Example 6

[0154] Based on the content disclosed in Example 1, the following modifications are made:

[0155] By mass fraction, the raw materials for the multi-effect corrosion and scale inhibitor meet the following requirements:

[0156] Thiourea derivative: 30%, polyacrylate metal salt: 6%, hydroxyasiatic acid: 8%, 1,2,4-triazole: 10%, and water: 46%.

[0157] The molecular weight of polyacrylate is 3000-5000.

[0158] The amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the following relationship: n1:n2:n3:n4 = 1:5:7:3.

[0159] The amount of alkaline solution n5 and the amount of intermediate n6 satisfy the relationship: n5:n6=5:1.

[0160] The polymerization reaction was carried out at a temperature of 110℃ for 4.0 h.

[0161] Example 7

[0162] Based on the content disclosed in Example 1, the following modifications are made:

[0163] By mass fraction, the raw materials for the multi-effect corrosion and scale inhibitor meet the following requirements:

[0164] Thiourea derivative: 30%, polyacrylate metal salt: 5%, hydroxyasiatic acid: 7%, 1,2,4-triazole: 11%, and water: 47%.

[0165] The molecular weight of polyacrylate is 4000-5000.

[0166] The amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the following relationship: n1:n2:n3:n4 = 1:4:7:4.

[0167] The amount of alkaline solution n5 and the amount of intermediate n6 satisfy the relationship: n5:n6=5:1.

[0168] The polymerization reaction was carried out at a temperature of 110℃ for 4.0 h.

[0169] Example 8

[0170] Based on the content disclosed in Example 1, the following modifications are made:

[0171] By mass fraction, the raw materials for the multi-effect corrosion and scale inhibitor meet the following requirements:

[0172] Thiourea derivative: 25%, polyacrylate metal salt: 10%, hydroxyasiatic acid: 10%, 1,2,4-triazole: 15%, and water: 40%.

[0173] The molecular weight of polyacrylate is 4000-5000.

[0174] The amounts of thiourea (n1), phosphorous acid (n2), paraformaldehyde (n3), and hydrochloric acid (n4) satisfy the following relationship: n1:n2:n3:n4 = 1:4:6:4.

[0175] The amount of alkaline solution n5 and the amount of intermediate n6 satisfy the relationship: n5:n6=8:1.

[0176] The polymerization reaction was carried out at a temperature of 110℃ for 4.0 h.

[0177] Example 9

[0178] Based on the multi-effect corrosion and scale inhibitor disclosed in Example 1, the following operations were further performed:

[0179] A dual-effect reagent with corrosion and scale inhibition, comprising a multi-effect corrosion and scale inhibitor, wherein the weight m1 of the multi-effect corrosion and scale inhibitor and the volume V1 of the dual-effect reagent satisfy the relationship: m1:V1=50g:1000L.

[0180] Comparative Example 1

[0181] Based on the content disclosed in Example 1, the following modifications are made:

[0182] Use conventional multi-effect corrosion and scale inhibitors, such as the multi-effect corrosion and scale inhibitors in the background art (2).

[0183] Comparative Example 2

[0184] Based on the content disclosed in Example 1, the following modifications are made:

[0185] Without adding thiourea derivatives, use water to replenish the other components of the multi-effect corrosion and scale inhibitor to 100%.

[0186] Comparative Example 3

[0187] Based on the content disclosed in Example 2, the following modifications are made:

[0188] Without adding polyacrylate metal salts, use water to replenish the other components of the multi-effect corrosion and scale inhibitor to 100%.

[0189] Comparative Example 4

[0190] Based on the content disclosed in Example 3, the following modifications are made:

[0191] Without adding 1,2,4-triazole, use water to replenish the other components of the multi-effect corrosion and scale inhibitor to 100%.

[0192] Comparative Example 5

[0193] Based on the content disclosed in Example 8, the following modifications are made:

[0194] Without adding hydroxyascorbic acid, use water to replenish the other components of the multi-effect corrosion and scale inhibitor to 100%.

[0195] Relevant experimental and effect data:

[0196] The performance of the multi-effect corrosion and scale inhibitors in Examples 1-8 and Comparative Examples 1-5 was tested respectively. The specific procedures included:

[0197] 1. Determination of scale inhibition rate

[0198] The scale inhibition performance of the prepared multi-effect corrosion and scale inhibitor was determined according to the "Q / SY 126-2014 Technical Specification for Corrosion and Scale Inhibitors for Oilfield Water Treatment".

[0199] 2. Determination of corrosion rate

[0200] (1) Solution preparation

[0201] To simulate a coalbed methane well site, a solution was prepared using on-site water, with an ion concentration of K. + 587.06 mg / L, Na + 45907.8 mg / L, Ca 2+ 62201.7 mg / L, Mg 2+ 4193.7 mg / L, Al 3+0.1196 mg / L, Fe 3+ 1086.3 mg / L, Cl - 225493.3 mg / L, HCO3 - 424.3 mg / L, Sr 2+ 11506.9 mg / L, Ba 2+ 1356.1 mg / L, SO4 2- 30.9 mg / L, NH4 + 743.4 mg / L.

[0202] (2) Test specimens

[0203] The experiment used A3 steel with dimensions of 50mm × 13mm × 1.5mm.

[0204] (3) Test Procedure

[0205] 1) Wipe the test piece clean with filter paper, then place it in a container filled with petroleum ether with a boiling range of 60℃~90℃. Remove the grease from the surface of the test piece with degreased cotton, then soak it in anhydrous ethanol for 5 minutes for further degreasing and dehydration. Remove the test piece, place it on filter paper, dry it with cold air, then wrap it with filter paper and store it in a desiccator. After 1 hour, measure the size and weigh it, accurate to 0.1mg.

[0206] 2) Add the prepared aqueous solution to a 1L container, and then add the prepared corrosion inhibitor solution to the test container using a pipette. Hang the test piece on the container and seal it with a rubber stopper. Place the test container in a constant temperature chamber and maintain the temperature at 50℃ for 72 hours.

[0207] 3) After the test, remove the test piece and place it in petroleum ether with a boiling range of 60℃~90℃. Remove the oil stains from the surface of the test piece with degreased cotton, and then soak it in anhydrous ethanol for 5 minutes for further degreasing and dehydration. Remove the test piece and soak it in acid cleaning solution for 5 minutes, while using tweezers to gently wipe the corrosion products on the surface of the test piece with a small amount of degreased cotton. Remove the test piece from the cleaning solution, rinse off the residual acid on the surface with tap water, and immediately immerse the test piece in sodium hydroxide solution (60g / L) for 30 seconds, then rinse with tap water, and then soak it in anhydrous ethanol for about 5 minutes, washing and dehydrating twice. Remove the test piece, place it on filter paper, dry it with cold air, then wrap the test piece with filter paper, place it in a desiccator, and weigh it after 1 hour, accurate to 0.1mg.

[0208] 4) Corrosion rate (v) corr Calculation of )

[0209]

[0210] In the formula: v corrThe corrosion rate is uniform, in mm / year; m is the mass of the specimen before the experiment, in g; m1 is the mass of the specimen after the experiment, in g; S is the total area of ​​the specimen, in cm². 2 t is the test time, in hours; ρ is the density of the sample material, in g / cm³. 3 .

[0211] According to the above process, the performance of the multi-effect corrosion and scale inhibitors in Examples 1 to 8 and Comparative Examples 1 to 5 was obtained. The amount of multi-effect corrosion and scale inhibitor added in Examples 1 and Comparative Examples 2 was 30 mg / L and 60 mg / L, respectively. The results are shown in Table 1.

[0212] Table 1. Performance results of the multi-effect corrosion and scale inhibitors in each embodiment and comparative example.

[0213]

[0214] As shown in Table 1, the multi-effect corrosion and scale inhibitor provided in Example 1 still exhibits good scale inhibition and corrosion inhibition properties under different addition amounts. However, in Comparative Example 2, without the addition of thiourea derivatives, the scale inhibition effect of the multi-effect corrosion and scale inhibitor is poor, and its corrosion inhibition ability is also poor. In addition, although Comparative Example 1 has a high ability to inhibit CaCO3 scale and CaSO4 scale under the same addition amount, its ability to inhibit BaSO4 scale is poor, and its corrosion inhibition ability is also poor.

[0215] Therefore, this application provides a multi-effect corrosion and scale inhibitor that combines scale inhibition and corrosion inhibition. This multi-effect corrosion and scale inhibitor improves its scale inhibition and corrosion inhibition performance through the synergistic effect of thiourea derivatives, polyacrylate metal salts, and hydroxyasiatic acid at the molecular level. This multi-effect corrosion and scale inhibitor can simultaneously exhibit good dispersion and chelation effects on CaCO3 scale, CaSO4 scale, and BaSO4 scale in produced water, resulting in high scale inhibition performance. The performance of this multi-effect corrosion and scale inhibitor is as follows: the scale inhibition rate for the three types of scale mentioned above is greater than 90%; in addition, the corrosion rate of A3 steel in the produced water of the simulated coalbed methane well site is less than 0.076 mm / year. Furthermore, the dissolved oxygen in the produced water of this well site was not removed. Therefore, this corrosion rate demonstrates that the multi-effect corrosion and scale inhibitor provided in this application, which has both scale inhibition and corrosion inhibition functions, improves the scale inhibition and corrosion inhibition effects of the corrosion and scale inhibitor under the conditions of high salinity and high dissolved oxygen content produced water.

[0216] Furthermore, this application provides a multi-effect scale and corrosion inhibitor that combines scale inhibition and corrosion inhibition. This multi-effect scale and corrosion inhibitor achieves a dual improvement in scale inhibition and corrosion inhibition performance through the synergistic effect of thiourea derivatives, polyacrylate metal salts, and hydroxyasiatic acid at the molecular level. This multi-effect scale and corrosion inhibitor is particularly suitable for treating produced water with high salinity and high dissolved oxygen content, and can significantly improve the scale inhibition and corrosion inhibition effects under these harsh conditions.

[0217] In addition, this application provides a multi-effect corrosion and scale inhibitor that combines scale inhibition and corrosion inhibition. This multi-effect corrosion and scale inhibitor can effectively inhibit various scales in the produced water of coalbed methane wells, and also has a good corrosion inhibition effect in water with high mineralization and high oxygen content.

[0218] Furthermore, this application provides a method for preparing a multi-effect corrosion and scale inhibitor that combines scale inhibition and corrosion inhibition. This method has a simple preparation principle and a simple synthesis process.

[0219] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A multi-effect corrosion and scale inhibitor, ingredients of the multi-effect corrosion and scale inhibitor satisfying, in mass fraction, the following relationships: 1,2,4-triazole: 10-15 parts; and the thiourea derivative containing a sulfur atom, a plurality of nitrogen atoms, and a plurality of phosphoric acid groups. Thiourea derivatives: 15 to 30 parts, polyacrylic acid metal salt: 5 to 10 parts, hydroxyl asiatic acid: 5 to 10 parts, and water; wherein, 2.The multi-effect corrosion and scale inhibitor according to claim 1, wherein the thiourea derivative has a molecular structure as shown in formula 1. 3.The multi-effect corrosion and scale inhibitor according to claim 1, wherein the polyacrylic acid salt has a molecular weight of 1000-5000. 4.The multi-effect corrosion and scale inhibitor according to claim 1, wherein the polyacrylic acid metal salt comprises sodium polyacrylate and / or ammonium polyacrylate. 5.The multi-effect corrosion and scale inhibitor according to claim 1, wherein ingredients of the multi-effect corrosion and scale inhibitor further satisfy: 1,2,4-triazole: 10-15 parts. 6.A method for preparing the multi-effect corrosion and scale inhibitor according to any one of claims 1-5, the method comprising: preparing a thiourea derivative; and mixing a polyacrylic acid metal salt, a hydroxyl asiatic acid, 1,2,4-triazole, and the thiourea derivative to obtain the multi-effect corrosion and scale inhibitor. 7.The method according to claim 6, wherein the step of preparing the thiourea derivative comprises the following steps: mixing thiourea, phosphorous acid, paraformaldehyde, and hydrochloric acid to obtain a mixed raw material; performing a polymerization reaction on the mixed raw material to obtain a crude intermediate; performing a purification treatment on the crude intermediate to obtain an intermediate; performing a neutralization reaction on a basic solution and the intermediate to obtain a neutral intermediate mixture; and performing distillation and drying on the neutral intermediate mixture to obtain the thiourea derivative; wherein the intermediate has a molecular structure as shown in formula 2. 8.The method according to claim 7, wherein a substance amount n1 of the thiourea, a substance amount n2 of the phosphorous acid, a substance amount n3 of the paraformaldehyde, and a substance amount n4 of the hydrochloric acid satisfy the relationship: n1:n2:n3:n4=1:(4-6):(6-8):(2-4); and / or a substance amount n5 of the basic solution and a substance amount n6 of the intermediate satisfy the relationship: n5:n6=(4-8):

1. 9.The method according to claim 7, wherein the polymerization reaction is performed at a temperature of 110-120℃ for 3.0-4.0h. 10.A double-effect agent with corrosion and scale inhibition, the double-effect agent comprising the multi-effect corrosion and scale inhibitor according to any one of claims 1-5, wherein a weight m1 of the multi-effect corrosion and scale inhibitor and a volume V1 of the double-effect agent satisfy the relationship: m1:V1=(30-60):1000, wherein if the unit of m1 is g, the unit of V1 is L. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Images