Environment-friendly sulfide removal agent for oil and gas fields

Abstract

The invention belongs to the technical field of desulfurization, and particularly relates to an environment-friendly sulfide removal agent for oil and gas fields. The sulfide removal agent is prepared from the following components in percentage by mass: 18%-30% of an oxidizing agent, 8%-12% of a main catalyst, 2%-4% of an auxiliary catalyst, 1%-4% of diethanol amine, 0.5%-1% of ethylenediamine tetraacetic acid, 1%-3% of alkylphenol polyoxyethylene ether, 0.5%-0.8% of polyoxyethylene sorbitan fatty acid ester, 5%-10% of a dispersing agent and the balance of water. The prepared environment-friendly sulfide removal agent for the oil and gas field has good chemical stability and dispersing performance, and has efficient removal capacity for both organic sulfur and inorganic sulfur.

Description

Technical Field

[0001] The present invention belongs to the technical field of desulfurization, and particularly relates to an environment-friendly sulfide remover for oil and gas fields. Background Art

[0002] During the exploitation process of oil and gas fields, sulfur-containing compounds such as hydrogen sulfide and methyl sulfide are generated. Sulfur-containing compounds not only affect life and health, but also corrode equipment such as production tubing strings and pipelines, causing production hazards. Therefore, it is necessary to remove hydrogen sulfide and other sulfur-containing compounds generated in industrial production processes such as oil and gas field exploitation as much as possible.

[0003] Currently, crude oil desulfurization usually adopts physical desulfurization, chemical desulfurization and biological desulfurization. Chemical desulfurization mainly removes sulfur-containing compounds such as hydrogen sulfide through chemical reactions by adding chemical agents and utilizing the principles of acid-base neutralization or oxidation-reduction. Due to the simple operation and strong practicability of the chemical absorption method, it has become a relatively common desulfurization method. The commonly used sulfide removers in the chemical absorption method mainly include alkanolamines, triazines, aldehyde amines, etc. Generally, they are added through the casing, and after being fully mixed and reacted with hydrogen sulfide in the tubing, organic polysulfides are generated, and through the separation in the separation workshop, the removal of hydrogen sulfide is realized.

[0004] The Chinese patent application document with the application publication number of CN111944560A discloses a desulfurizer for oil and gas fields and its preparation method. The desulfurizer includes a liquid triazine-based desulfurization main agent, and a scale inhibitor, a synergist and a dispersant are added. Among them, the mass fraction of the liquid triazine-based desulfurization main agent is 60%-80%, the mass fraction of the scale inhibitor is 5%-10%, the mass fraction of the synergist is 5%-10%, and the mass fraction of the dispersant is the balance. However, this desulfurizer can only treat hydrogen sulfide, and has a poor treatment effect on sulfur-containing compounds such as organic sulfur. The conditions of oil fields are complex, and most of them contain substances such as hydrogen sulfide and organic sulfur. This desulfurizer cannot meet the high-efficiency desulfurization requirements of organic sulfur and has certain limitations. Summary of the Invention

[0005] The existing sulfide removers have a low ability to remove organic sulfur; to solve this problem, the present invention provides an environment-friendly sulfide remover for oil and gas fields.

[0006] To achieve the purpose of the present invention, the following technical solutions are adopted in the present invention: The present invention provides an environment-friendly sulfide remover for oil and gas fields, which is composed of the following components in mass percentage: 18% - 30% oxidant, 8% - 12% main catalyst, 2% - 4% auxiliary catalyst, 1% - 4% diethanolamine, 0.5% - 1% ethylenediaminetetraacetic acid, 1% - 3% alkylphenol polyoxyethylene ether, 0.5% - 0.8% polyoxyethylene sorbitan fatty acid ester, 5% - 10% dispersant, and the balance is water; The main catalyst is prepared by reacting 2,4,6 - tris(4 - carboxyphenyl)-1,3,5 - triazine with 2-(4 - aminophenyl)-5 - aminobenzimidazole in a molar ratio of 1∶(1.1 - 1.5).

[0007] By adopting the above technical solution, the oxidant, the main catalyst and the auxiliary catalyst form the main components of the sulfide remover. The double - catalytic system synergistically improves the desulfurization efficiency, and is supplemented with components such as polyoxyethylene sorbitan fatty acid ester and dispersant, enabling the sulfide remover to quickly and fully contact with sulfides and accelerating the rate of the desulfurization reaction; the main catalyst contains structures such as benzimidazole ring and triazine ring, which can not only effectively activate the oxidant, but also provide abundant adsorption and reaction sites for sulfides; thus, the environmentally friendly sulfide remover for oil and gas fields has high desulfurization performance, good chemical stability and dispersibility.

[0008] By adopting the above technical solution, within the range of the molar ratio of 1∶(1.1 - 1.5) of 2,4,6 - tris(4 - carboxyphenyl)-1,3,5 - triazine to 2-(4 - aminophenyl)-5 - aminobenzimidazole, 2,4,6 - tris(4 - carboxyphenyl)-1,3,5 - triazine can fully participate in the reaction to form a framework structure with uniformly distributed active sites.

[0009] Preferably, the oxidant is selected from one of hydrogen peroxide and tert - butyl hydroperoxide.

[0010] Preferably, the dispersant is prepared by mixing sodium polyacrylate, polyethylene glycol and polyvinylpyrrolidone in a mass ratio of (1 - 3)∶(1 - 2)∶1.

[0011] By adopting the above technical solution, at this ratio, sodium polyacrylate can provide strong electrostatic repulsion, polyethylene glycol reduces the surface tension, and polyvinylpyrrolidone forms a stable protective film. The three cooperate with each other to avoid particle agglomeration, making the dispersibility of the sulfide remover better and improving the desulfurization efficiency of the sulfide remover.

[0012] Preferably, the preparation method of the main catalyst includes the following steps: Mix 2,4,6 - tris(4 - carboxyphenyl)-1,3,5 - triazine, 2-(4 - aminophenyl)-5 - aminobenzimidazole, N,N'-dicyclohexylcarbodiimide, 4 - dimethylaminopyridine and dimethyl sulfoxide evenly, heat up for reaction, wash, and dry to obtain the main catalyst.

[0013] By adopting the above technical solution, condensation reaction occurs between 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine and 2-(4-aminophenyl)-5-aminobenzimidazole to form an amide bond, forming a main catalyst with a covalent porous structure. There are a large number of active sites such as nitrogen atoms on the triazine ring and the benzimidazole ring, which can effectively activate the oxidant, accelerate the oxidative desulfurization reaction of sulfides, and improve the desulfurization ability of the sulfide removing agent.

[0014] Preferably, the molar ratio of N,N'-dicyclohexylcarbodiimide to 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine is (1.05 - 1.1)∶1; the dosage of 4-dimethylaminopyridine is 3% - 5% of the mass of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine; the dosage ratio of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine to dimethyl sulfoxide is 1 g∶(13 - 15) mL.

[0015] By adopting the above technical solution, if there is too much N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, it is easy to cause an increase in impurities in the reaction system and an increase in side reactions, affecting the structure and performance of the product. If the dosages of N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine are too small, the reaction is likely to be incomplete, affecting the number of active sites of the main catalyst and thus reducing the catalytic activity.

[0016] Preferably, the steps of the temperature-raising reaction are specifically as follows: first, raise the temperature to 80 - 100 °C and react for 12 - 20 h, second, raise the temperature to 100 - 120 °C and react for 24 - 36 h, and third, raise the temperature to 120 - 130 °C and react for 45 - 48 h.

[0017] By adopting the above technical solution, the three-stage temperature-raising reaction can enable better cross-linking and arrangement between molecular chains, forming a stable and regular three-dimensional structure, and avoiding the problems of violent reaction and uneven cross-linking of molecular chains caused by directly raising the temperature to a high temperature in one step.

[0018] Preferably, the preparation method of the co-catalyst includes the following steps: (1) Mix manganese nitrate, molecular sieve and absolute ethanol evenly, impregnate, dry, and oxidatively calcine to obtain porous manganese oxide; (2) Mix porous manganese oxide, cobalt nitrate and absolute ethanol evenly, impregnate, dry, and oxidatively calcine to obtain cobalt-modified porous manganese oxide; (3) Mix cobalt-modified porous manganese oxide, heteropolyacid and water evenly, impregnate, wash, and dry to obtain the co-catalyst.

[0019] By adopting the above technical solution, the porous manganese oxide prepared in step (1) has a porous structure and a relatively large specific surface area, which can provide more active sites and contribute to the rapid transmission of sulfides in the pores of the cocatalyst; in step (2), the porous manganese oxide is cobalt-modified to improve the activity of the cocatalyst; in step (3), the heteropolyacid has strong acidity and redox properties, and can interact with the cobalt-modified porous manganese oxide to form a more efficient active center. In the oxidative desulfurization reaction, the heteropolyacid can provide protons and electrons to promote the oxidation reaction of sulfides; at the same time, the heteropolyacid can further expand the pores of the cobalt-modified porous manganese oxide through electrostatic interaction, improving the desulfurization efficiency.

[0020] Preferably, in the step (1), the dosage ratio of manganese nitrate, molecular sieve and absolute ethanol is 1 g∶(0.65 - 0.8) g∶(4 - 6) mL.

[0021] By adopting the above technical solution, within this dosage range, the porous manganese oxide has a rich pore structure with pore diameters and a relatively large specific surface area.

[0022] Preferably, in the step (1), the oxidative calcination process is as follows: heating to 500 - 600 °C at a heating rate of 5 °C / min in an oxygen atmosphere and calcining for 2 - 4 h.

[0023] Preferably, in the step (2), the dosage ratio of porous manganese oxide, cobalt nitrate and absolute ethanol is 1 g∶(0.07 - 0.15) g∶(5 - 7) mL.

[0024] By adopting the above technical solution, the introduction of cobalt can improve the structure of the porous manganese oxide, increase the active sites on the catalyst surface, and at the same time enhance the structural stability of the porous manganese oxide, enabling it to maintain long-term stable catalytic performance; by adjusting the dosage of cobalt, the catalyst performance can reach the optimum.

[0025] Preferably, in the step (2), the oxidative calcination process is as follows: heating to 400 - 500 °C at a heating rate of 5 °C / min in an oxygen atmosphere and calcining for 3 - 5 h.

[0026] Preferably, in the step (3), the dosage ratio of cobalt-modified porous manganese oxide, heteropolyacid and water is 1 g∶(2.5 - 3) g∶(80 - 90) mL.

[0027] By adopting the above technical solution, within this dosage range, the loading amount of the heteropolyacid is appropriate; too much heteropolyacid is likely to aggregate on the surface of the cobalt-modified porous manganese oxide, resulting in uneven distribution of active sites and blocking the pores; too little heteropolyacid cannot fully adsorb and oxidize sulfides, and the desulfurization effect deteriorates.

[0028] The present invention also provides a preparation method of the above-mentioned environmentally friendly sulfide remover for oil and gas fields, comprising the following steps: Mix the main catalyst, co-catalyst, diethanolamine, ethylenediaminetetraacetic acid, alkylphenol polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, dispersant and water evenly, and then add the oxidant and mix evenly to obtain an environmentally friendly sulfide scavenger for oil and gas fields.

[0029] In summary, the beneficial effects of the present invention are as follows: (1) In the present invention, the oxidant, main catalyst, co-catalyst, polyoxyethylene sorbitan fatty acid ester, dispersant and other components are compounded, so that the environmentally friendly sulfide scavenger for oil and gas fields has good chemical stability and dispersion performance, and has high removal ability for both organic sulfur and inorganic sulfur; (2) In the present invention, through the condensation reaction of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine with 2-(4-aminophenyl)-5-aminobenzimidazole, a main catalyst with a covalent porous structure is formed. The presence of triazine rings and benzimidazole rings can provide a large number of nitrogen atom active sites, effectively activating the oxidant and improving the desulfurization ability of the sulfide scavenger; (3) In the present invention, heteropolyacid is loaded on cobalt-modified porous manganese oxide. Cobalt-modified porous manganese oxide has a large specific surface area and a rich pore structure, providing a large number of adsorption sites. Sulfide can be adsorbed onto the surface and into the pores of cobalt-modified porous manganese oxide through adsorption; meanwhile, heteropolyacid has strong redox properties and acts as an oxidation catalyst during the desulfurization process, further enhancing the removal ability for sulfide. Description of the Drawings

[0030] Figure 1 This is the H2S desulfurization rate results of the examples and comparative examples of the present invention; Figure 2 This is the DBT desulfurization rate results of the examples and comparative examples of the present invention; Figure 3 This is the pore size distribution diagram of the co-catalysts prepared in Example 1 and Comparative Examples 4 and 5 of the present invention. Detailed Embodiments

[0031] The technical solutions of the present invention will be elaborated in detail below with reference to several representative embodiments of the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are all conventional methods. The materials, reagents, etc. used in the following examples and comparative examples can all be obtained from commercial channels unless otherwise specified.

[0033] The heteropolyacid used in the following examples and comparative examples is 12-molybdovanadophosphoric acid hydrate. <00>

[0034] Example 1 An environment-friendly sulfide remover for oil and gas fields in this embodiment is composed of components with the following masses: 25 g of tert-butyl hydroperoxide, 10 g of main catalyst, 3 g of auxiliary catalyst, 1 g of diethanolamine, 0.8 g of ethylenediaminetetraacetic acid, 3 g of alkylphenol polyoxyethylene ether, 0.7 g of polyoxyethylene sorbitan fatty acid ester, 2 g of sodium polyacrylate, 4 g of polyethylene glycol, 2 g of polyvinylpyrrolidone, and 48.5 g of water.

[0035] A preparation method of the above-mentioned environment-friendly sulfide remover for oil and gas fields in this embodiment is as follows: Stir 10 g of main catalyst, 3 g of auxiliary catalyst, 1 g of diethanolamine, 0.8 g of ethylenediaminetetraacetic acid, 3 g of alkylphenol polyoxyethylene ether, 0.7 g of polyoxyethylene sorbitan fatty acid ester, 2 g of sodium polyacrylate, 4 g of polyethylene glycol, 2 g of polyvinylpyrrolidone and 48.5 g of water for 30 min, add 25 g of tert-butyl hydroperoxide and continue stirring for 1 h to obtain the environment-friendly sulfide remover for oil and gas fields.

[0036] A preparation method of the main catalyst in this embodiment is as follows: Add 4.41 g of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 3.14 g of 2-(4-aminophenyl)-5-aminobenzimidazole, 0.14 g of 4-dimethylaminopyridine, 2.21 g of N,N'-dicyclohexylcarbodiimide and 62 mL of dimethyl sulfoxide into a three-necked flask and stir for 2 h. Heat up to 90 °C for the first time and react for 20 h, heat up to 110 °C for the second time and react for 36 h, heat up to 125 °C for the third time and react for 45 h. Wash with dilute hydrochloric acid, deionized water and acetone for 5 times respectively, and dry in a vacuum drying oven at 80 °C for 12 h to obtain the main catalyst.

[0037] A preparation method of the auxiliary catalyst in this embodiment is as follows: (1) Add 5 g of manganese nitrate, 3.5 g of KIT-6 molecular sieve and 25 mL of absolute ethanol into a three-necked flask and stir for 6 h. Dry in a vacuum drying oven at 70 °C for 8 h, transfer to a muffle furnace and calcine at a heating rate of 5 °C / min in an oxygen atmosphere to 500 °C for 3 h; add 2 g of the calcined product into 60 mL of 2 mol / L sodium hydroxide aqueous solution, heat up to 60 °C and stir for 5 h, wash with deionized water, and dry in a vacuum drying oven at 60 °C for 8 h to obtain porous manganese oxide; (2) Add 3 g of porous manganese oxide, 0.27 g of cobalt nitrate and 15 mL of absolute ethanol into a three-necked flask and stir for 12 h. Dry in a vacuum drying oven at 70 °C for 10 h, transfer to a muffle furnace and calcine at a heating rate of 5 °C / min in an oxygen atmosphere to 450 °C for 5 h to obtain cobalt-modified porous manganese oxide; (3) Add 1 g of cobalt-modified porous manganese oxide, 2.6 g of heteropolyacid, and 90 mL of water to a three-necked flask, stir for 36 h, wash with deionized water, and dry in a vacuum drying oven at 80 °C for 12 h to obtain the co-catalyst.

[0038] Example 2 An environmentally friendly sulfide scavenger for oil and gas fields in this example is composed of the following components by mass: 18 g of tert-butyl hydroperoxide, 12 g of the main catalyst, 2 g of the co-catalyst, 4 g of diethanolamine, 0.5 g of ethylenediaminetetraacetic acid, 1 g of alkylphenol polyoxyethylene ether, 0.6 g of polyoxyethylene sorbitan fatty acid ester, 4 g of sodium polyacrylate, 4 g of polyethylene glycol, 2 g of polyvinylpyrrolidone, and 51.9 g of water.

[0039] A preparation method of the environmentally friendly sulfide scavenger for oil and gas fields in this example is as follows: Stir 12 g of the main catalyst, 2 g of the co-catalyst, 4 g of diethanolamine, 0.5 g of ethylenediaminetetraacetic acid, 1 g of alkylphenol polyoxyethylene ether, 0.6 g of polyoxyethylene sorbitan fatty acid ester, 4 g of sodium polyacrylate, 4 g of polyethylene glycol, 2 g of polyvinylpyrrolidone, and 51.9 g of water for 30 min, add 18 g of tert-butyl hydroperoxide and continue stirring for 1 h to obtain the environmentally friendly sulfide scavenger for oil and gas fields.

[0040] A preparation method of the main catalyst in this example is as follows: Add 4.41 g of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 2.47 g of 2-(4-aminophenyl)-5-aminobenzimidazole, 0.17 g of 4-dimethylaminopyridine, 2.23 g of N,N'-dicyclohexylcarbodiimide, and 66 mL of dimethyl sulfoxide to a three-necked flask, stir for 2 h, heat up to 80 °C for the first time and react for 16 h, heat up to 100 °C for the second time and react for 28 h, heat up to 120 °C for the third time and react for 48 h, wash 5 times with dilute hydrochloric acid, deionized water, and acetone respectively, and dry in a vacuum drying oven at 80 °C for 12 h to obtain the main catalyst.

[0041] A preparation method of the co-catalyst in this example is as follows: (1) Add 5 g of manganese nitrate, 3.25 g of KIT-6 molecular sieve, and 20 mL of absolute ethanol to a three-necked flask, stir for 6 h, dry in a vacuum drying oven at 70 °C for 8 h, transfer to a muffle furnace, and calcine at 600 °C for 4 h at a heating rate of 5 °C / min in an oxygen atmosphere; add 2 g of the calcined product to 60 mL of 2 mol / L sodium hydroxide aqueous solution, heat up to 60 °C and stir for 5 h, wash with deionized water, and dry in a vacuum drying oven at 60 °C for 8 h to obtain porous manganese oxide; (2) Add 3 g of porous manganese oxide, 0.36 g of cobalt nitrate and 18 mL of absolute ethanol to a three-necked flask, stir for 12 h, dry in a vacuum drying oven at 70 °C for 10 h, transfer to a muffle furnace, and heat up to 400 °C at a heating rate of 5 °C / min in an oxygen atmosphere and calcine for 3 h to obtain cobalt-modified porous manganese oxide; (3) Add 1 g of cobalt-modified porous manganese oxide, 2.5 g of heteropolyacid and 85 mL of water to a three-necked flask, stir for 36 h, wash with deionized water, and dry in a vacuum drying oven at 80 °C for 12 h to obtain the co-catalyst.

[0042] Example 3 An environmentally friendly sulfide scavenger for oil and gas fields in this example is composed of the following components by mass: 30 g of hydrogen peroxide, 8 g of main catalyst, 3 g of co-catalyst, 3 g of diethanolamine, 1 g of ethylenediaminetetraacetic acid, 2 g of alkylphenol polyoxyethylene ether, 0.5 g of polyoxyethylene sorbitan fatty acid ester, 4 g of sodium polyacrylate, 1 g of polyethylene glycol, 1 g of polyvinylpyrrolidone, 48.5 g of water.

[0043] A preparation method of the above-mentioned environmentally friendly sulfide scavenger for oil and gas fields in this example is as follows: Stir 8 g of main catalyst, 3 g of co-catalyst, 3 g of diethanolamine, 1 g of ethylenediaminetetraacetic acid, 2 g of alkylphenol polyoxyethylene ether, 0.5 g of polyoxyethylene sorbitan fatty acid ester, 4 g of sodium polyacrylate, 1 g of polyethylene glycol, 1 g of polyvinylpyrrolidone and 48.5 g of water for 30 min, add 30 g of hydrogen peroxide and continue to stir for 1 h to obtain an environmentally friendly sulfide scavenger for oil and gas fields.

[0044] A preparation method of the main catalyst in this example is as follows: Add 4.41 g of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 3.36 g of 2-(4-aminophenyl)-5-aminobenzimidazole, 0.22 g of 4-dimethylaminopyridine, 2.17 g of N,N'-dicyclohexylcarbodiimide and 58 mL of dimethyl sulfoxide to a three-necked flask, stir for 2 h, heat up to 100 °C for the first time and react for 12 h, heat up to 120 °C for the second time and react for 24 h, heat up to 130 °C for the third time and react for 46 h, wash 5 times with dilute hydrochloric acid, deionized water and acetone respectively, and dry in a vacuum drying oven at 80 °C for 12 h to obtain the main catalyst.

[0045] A preparation method of the co-catalyst in this example is as follows: (1) Add 5 g of manganese nitrate, 4 g of KIT-6 molecular sieve and 30 mL of absolute ethanol into a three-necked flask, stir for 6 h, place it in a vacuum drying oven at 70 °C for 8 h, transfer it to a muffle furnace, and heat it to 540 °C at a heating rate of 5 °C / min in an oxygen atmosphere and calcine for 2 h; add 2 g of the calcined product into 60 mL of 2 mol / L sodium hydroxide aqueous solution, heat it to 60 °C and stir for 5 h, wash it with deionized water, and place it in a vacuum drying oven at 60 °C for 8 h to obtain porous manganese oxide; (2) Add 3 g of porous manganese oxide, 0.21 g of cobalt nitrate and 21 mL of absolute ethanol into a three-necked flask, stir for 12 h, place it in a vacuum drying oven at 70 °C for 10 h, transfer it to a muffle furnace, and heat it to 500 °C at a heating rate of 5 °C / min in an oxygen atmosphere and calcine for 4 h to obtain cobalt-modified porous manganese oxide; (3) Add 1 g of cobalt-modified porous manganese oxide, 2.8 g of heteropolyacid and 90 mL of water into a three-necked flask, stir for 36 h, wash it with deionized water, and place it in a vacuum drying oven at 80 °C for 12 h to obtain a co-catalyst.

[0046] Example 4 An environmentally friendly sulfide scavenger for oil and gas fields in this example is composed of components with the following masses: 22 g of hydrogen peroxide, 10 g of main catalyst, 4 g of co-catalyst, 3 g of diethanolamine, 1 g of ethylenediaminetetraacetic acid, 2 g of alkylphenol polyoxyethylene ether, 0.8 g of polyoxyethylene sorbitan fatty acid ester, 2 g of sodium polyacrylate, 2 g of polyethylene glycol, 2 g of polyvinylpyrrolidone, 51.2 g of water.

[0047] A preparation method of the above-mentioned environmentally friendly sulfide scavenger for oil and gas fields in this example is as follows: Stir 10 g of main catalyst, 4 g of co-catalyst, 3 g of diethanolamine, 1 g of ethylenediaminetetraacetic acid, 2 g of alkylphenol polyoxyethylene ether, 0.8 g of polyoxyethylene sorbitan fatty acid ester, 2 g of sodium polyacrylate, 2 g of polyethylene glycol, 2 g of polyvinylpyrrolidone and 51.2 g of water for 30 min, add 22 g of hydrogen peroxide and continue to stir for 1 h to obtain an environmentally friendly sulfide scavenger for oil and gas fields.

[0048] A preparation method of the main catalyst in this example is as follows: 4.41 g of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 2.69 g of 2-(4-aminophenyl)-5-aminobenzimidazole, 0.18 g of 4-dimethylaminopyridine, 2.26 g of N,N'-dicyclohexylcarbodiimide and 60 mL of dimethyl sulfoxide were added to a three-necked flask and stirred for 2 h. The temperature was raised to 90 °C for the first time and reacted for 14 h, then raised to 115 °C for the second time and reacted for 30 h, and then raised to 130 °C for the third time and reacted for 48 h. It was washed 5 times with dilute hydrochloric acid, deionized water and acetone respectively, and placed in a vacuum drying oven at 80 °C for 12 h to obtain the main catalyst.

[0049] The preparation method of the co-catalyst in this example is as follows: (1) 5 g of manganese nitrate, 3.75 g of KIT-6 molecular sieve and 30 mL of absolute ethanol were added to a three-necked flask and stirred for 6 h, placed in a vacuum drying oven at 70 °C for 8 h, transferred to a muffle furnace and calcined at a heating rate of 5 °C / min to 580 °C for 4 h in an oxygen atmosphere; 2 g of the calcined product was added to 60 mL of 2 mol / L sodium hydroxide aqueous solution, the temperature was raised to 60 °C and stirred for 5 h, washed with deionized water, and placed in a vacuum drying oven at 60 °C for 8 h to obtain porous manganese oxide. (2) 3 g of porous manganese oxide, 0.45 g of cobalt nitrate and 21 mL of absolute ethanol were added to a three-necked flask and stirred for 12 h, placed in a vacuum drying oven at 70 °C for 10 h, transferred to a muffle furnace and calcined at a heating rate of 5 °C / min to 480 °C for 4 h in an oxygen atmosphere to obtain cobalt-modified porous manganese oxide. (3) 1 g of cobalt-modified porous manganese oxide, 3 g of heteropolyacid and 80 mL of water were added to a three-necked flask and stirred for 36 h, washed with deionized water, and placed in a vacuum drying oven at 80 °C for 12 h to obtain the co-catalyst.

[0050] Comparative Example 1 - Comparative Example 3 The difference from Example 1 is that the environmentally friendly sulfide scavenger for oil and gas fields prepared in Comparative Example 1 - Comparative Example 3 is composed of the components in Table 1, and the rest are the same as Example 1.

[0051] Table 1 Components of the environmentally friendly sulfide scavenger for oil and gas fields

[0052] Comparative Example 4 The difference from Example 1 is that in the preparation of the co-catalyst in this comparative example, steps (2) and (3) are not carried out, and the rest are the same as Example 1.

[0053] Comparative Example 5 The difference from Example 1 is that in the preparation of the co-catalyst in this comparative example, step (3) is not carried out, and the rest are the same as Example 1.

[0054] Comparative Example 6 The difference from Example 1 is that in the preparation step (3) of the co-catalyst in this comparative example, the mass ratio of the cobalt-modified porous manganese oxide to the heteropolyacid is 1:5.

[0055] Comparative Example 7 The difference from Example 1 is that the main catalyst in this comparative example is prepared by reacting 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine and 2-(4-aminophenyl)-5-aminobenzimidazole in a molar ratio of 1:4.8, and the rest is the same as Example 1.

[0056] Comparative Example 8 The difference from Example 1 is that an equal amount of triaminobenzene is used instead of 2-(4-aminophenyl)-5-aminobenzimidazole in this comparative example, and the rest are the same as Example 1.

[0057] Related performance tests The desulfurization performance of the environmentally friendly sulfide removers for oil and gas fields prepared in Examples 1 to 4 and Comparative Examples 1 to 8 was tested. Hydrogen sulfide (H2S) and dibenzothiophene (DBT) were used as representatives to prepare a simulation system with a sulfur content of 500 ppm. The environmentally friendly sulfide removers for oil and gas fields were added and reacted at 75°C for 3 hours. The test results are shown in FIG. Figure 1 and Figure 2 , Figure 1 is the H2S desulfurization rate result, Figure 2 This is the DBT desulfurization rate result.

[0058] Combine Figure 1 and Figure 2 We can get: By comparing Comparative Examples 1, 2 and 3 with Example 1, it can be seen that changing the content of the main catalyst, co-catalyst and other components in the desulfurization agent will lead to a decrease in the desulfurization rate, proving that the component ratio of the desulfurization agent of the present invention is optimal.

[0059] Figure 3 The pore size distribution diagram of the cocatalyst prepared in Example 1, Comparative Example 4 and Comparative Example 5; by comparing Comparative Example 4, Example 5 with Example 1 and combining Figure 3 It can be seen that cobalt modification and the introduction of heteropolyacid can expand the pore size of the cocatalyst, facilitate the rapid transport of sulfides in the pores of the cocatalyst, and improve the sulfide removal rate.

[0060] From the comparison between Comparative Example 6 and Example 1, it can be seen that excessive use of heteropolyacid may accumulate in the pores of the cobalt-modified porous manganese oxide, making it difficult for sulfides to reach the active sites and reducing the desulfurization performance.

[0061] It can be seen from the comparison between Comparative Example 7 and Example 1 that excessive 2-(4-aminophenyl)-5-aminobenzimidazole may cause disorder inside the main catalyst and reduce the sulfide removal rate.

[0062] It can be seen from the comparison between Comparative Example 8 and Example 1 that the introduction of the benzimidazole ring mainly has a greater impact on DBT organic sulfur; the nitrogen atom on the benzimidazole ring has a lone pair of electrons, and the whole ring has a certain conjugated system, which can activate oxidants such as tert-butyl hydroperoxide and improve the desulfurization rate.

[0063] The above provides an exemplary description of the present invention. It should be noted that without departing from the core of the present invention, any simple deformation, modification, or equivalent substitution that can be made by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

Claims

1. An environmentally friendly sulfide remover for oil and gas fields, characterized in that, It is composed of components with the following mass percentages: 18% - 30% oxidant, 8% - 12% main catalyst, 2% - 4% co - catalyst, 1% - 4% diethanolamine, 0.5% - 1% ethylenediaminetetraacetic acid, 1% - 3% alkylphenol polyoxyethylene ether, 0.5% - 0.8% polyoxyethylene sorbitan fatty acid ester, 5% - 10% dispersant, and the balance is water; The main catalyst is prepared by reacting 2,4,6 - tris(4 - carboxyphenyl)-1,3,5 - triazine and 2-(4 - aminophenyl)-5 - aminobenzimidazole in a molar ratio of 1∶(1.1 - 1.5).

2. The environmentally friendly sulfide remover for oil and gas fields according to claim 1, wherein The oxidant is selected from one of hydrogen peroxide and tert - butyl hydroperoxide.

3. An environment-friendly sulfide remover for oil and gas fields according to claim 1, characterized in that, The dispersant is prepared by mixing sodium polyacrylate, polyethylene glycol and polyvinylpyrrolidone in a mass ratio of (1 - 3)∶(1 - 2)∶1.

4. An environmentally friendly sulfide remover for oil and gas fields according to claim 1, characterized in that, The preparation method of the main catalyst includes the following steps: Mix 2,4,6 - tris(4 - carboxyphenyl)-1,3,5 - triazine, 2-(4 - aminophenyl)-5 - aminobenzimidazole, N,N'-dicyclohexylcarbodiimide, 4 - dimethylaminopyridine and dimethyl sulfoxide uniformly, raise the temperature for reaction, wash, and dry to obtain the main catalyst.

5. The environmentally friendly sulfide scavenger for oil and gas fields according to claim 4, wherein, The molar ratio of N,N'-dicyclohexylcarbodiimide to 2,4,6 - tris(4 - carboxyphenyl)-1,3,5 - triazine is (1.05 - 1.1)∶1; the dosage of 4 - dimethylaminopyridine is 3% - 5% of the mass of 2,4,6 - tris(4 - carboxyphenyl)-1,3,5 - triazine; the dosage ratio of 2,4,6 - tris(4 - carboxyphenyl)-1,3,5 - triazine to dimethyl sulfoxide is 1g∶(13 - 15)mL.

6. The environmentally friendly sulfide remover for oil and gas fields according to claim 4, wherein The specific steps of the temperature - raising reaction are as follows: raise the temperature to 80 - 100°C for reaction for 12 - 20h for the first time, raise the temperature to 100 - 120°C for reaction for 24 - 36h for the second time, and raise the temperature to 120 - 130°C for reaction for 45 - 48h for the third time.

7. An environmentally friendly sulfide remover for oil and gas fields according to claim 1, characterized in that, The preparation method of the co - catalyst includes the following steps: (1) Mix manganese nitrate, molecular sieve and absolute ethanol uniformly, impregnate, dry, and oxidize and calcine to obtain porous manganese oxide; (2) Mix porous manganese oxide, cobalt nitrate and absolute ethanol uniformly, impregnate, dry, and oxidize and calcine to obtain cobalt - modified porous manganese oxide; (3) Mix cobalt - modified porous manganese oxide, heteropolyacid and water uniformly, impregnate, wash, and dry to obtain the co - catalyst.

8. An environment-friendly sulfide remover for oil and gas fields according to claim 7, characterized in that, In the step (1), the dosage ratio of manganese nitrate, molecular sieve and absolute ethanol is 1g∶(0.65 - 0.8)g∶(4 - 6)mL.

9. An environmentally friendly sulfide remover for oil and gas fields according to claim 7, characterized in that, In the step (2), the dosage ratio of porous manganese oxide, cobalt nitrate and absolute ethanol is 1g∶(0.07 - 0.15)g∶(5 - 7)mL.

10. An environment-friendly sulfide remover for oil and gas fields according to claim 7, characterized in that In the step (3), the dosage ratio of cobalt - modified porous manganese oxide, heteropolyacid and water is 1g∶(2.5 - 3)g∶(80 - 90)mL.

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