An environmentally friendly sulfide remover for oil and gas fields

Abstract

The present invention belongs to the field of desulfurization technology and specifically relates to an environmentally friendly sulfide remover for oil and gas fields. The sulfide remover comprises the following components by weight: 18%-30% oxidant, 8%-12% primary catalyst, 2%-4% cocatalyst, 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 being water. The environmentally friendly sulfide remover for oil and gas fields prepared by the present invention has good chemical stability and dispersibility, and has high efficiency in removing both organic and inorganic sulfur.

Description

Technical Field

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

[0002] During oil and gas field extraction, sulfur compounds such as hydrogen sulfide and methyl sulfide are produced. These compounds not only pose a threat to human health but also corrode equipment such as production tubing and pipelines, posing production risks. Therefore, it is crucial to remove hydrogen sulfide and other sulfur compounds produced during industrial production processes, such as oil and gas field extraction, as much as possible.

[0003] Currently, crude oil desulfurization is typically achieved through physical, chemical, and biological desulfurization. Chemical desulfurization primarily involves the addition of chemical agents, utilizing acid-base neutralization or redox principles to remove sulfur-containing compounds such as hydrogen sulfide through chemical reactions. Chemical absorption has become a popular desulfurization method due to its simplicity and practicality. Commonly used sulfide removers in chemical absorption include alcoholamines, triazines, and aldehydeamines. These are typically added via casing and react with hydrogen sulfide within the oil pipeline to form organic polysulfides. These are then separated in a separation chamber to remove the hydrogen sulfide.

[0004] Chinese patent application publication number CN111944560A discloses a desulfurizer for oil and gas fields and its preparation method. The desulfurizer comprises a liquid triazine desulfurizer, a scale inhibitor, a synergist, and a dispersant. The mass fraction of the liquid triazine desulfurizer 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 remainder. However, this desulfurizer can only treat hydrogen sulfide and is less effective at treating sulfur-containing compounds such as organic sulfur. Oilfield conditions are complex, and most oilfields contain substances such as hydrogen sulfide and organic sulfur. This desulfurizer cannot meet the demand for efficient desulfurization of organic sulfur, thus having certain limitations. Summary of the Invention

[0005] Existing desulfurizers have a low ability to remove organic sulfur. In order to solve this problem, the present invention provides an environmentally friendly desulfurizer for oil and gas fields.

[0006] In order to achieve the purpose of the present invention, the present invention adopts the following technical solutions:

[0007] The present invention provides an environmentally friendly sulfide remover for oil and gas fields, which is composed of the following components in percentage by mass:

[0008] 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;

[0009] The main catalyst is prepared by reacting 2,4,6-tris(4-carboxylphenyl)-1,3,5-triazine with 2-(4-aminophenyl)-5-aminobenzimidazole in a molar ratio of 1:(1.1-1.5).

[0010] By adopting the above technical solution, the oxidant, the main catalyst and the auxiliary catalyst constitute the main components of the sulfide remover, and the dual catalytic system synergistically improves the desulfurization efficiency. Assisted by components such as polyoxyethylene sorbitan fatty acid ester and a dispersant, the sulfide remover quickly and fully contacts the sulfide, thereby accelerating the rate of the desulfurization reaction. The main catalyst contains structures such as a benzimidazole ring and a triazine ring, which can not only effectively activate the oxidant, but also provide abundant adsorption and reaction sites for the sulfide. This ensures that the environmentally friendly sulfide remover for oil and gas fields has efficient desulfurization performance, good chemical stability and dispersion properties.

[0011] By adopting the above technical solution, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine and 2-(4-aminophenyl)-5-aminobenzimidazole are in a molar ratio range of 1:(1.1-1.5), so that 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine can fully participate in the reaction to form a skeleton structure with uniformly distributed active sites.

[0012] Preferably, the oxidant is selected from one of hydrogen peroxide and tert-butyl hydroperoxide.

[0013] Preferably, the dispersant is prepared by mixing sodium polyacrylate, polyethylene glycol and polyvinyl pyrrolidone in a mass ratio of (1-3): (1-2): 1.

[0014] By adopting the above technical solution, at this ratio, sodium polyacrylate can provide stronger electrostatic repulsion, polyethylene glycol reduces surface tension, and polyvinyl pyrrolidone 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.

[0015] Preferably, the preparation method of the main catalyst comprises the following steps:

[0016] 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 2-(4-aminophenyl)-5-aminobenzimidazole, N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and dimethyl sulfoxide are uniformly mixed, heated for reaction, washed and dried to obtain a main catalyst.

[0017] By adopting the above technical solution, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine undergoes a condensation reaction with 2-(4-aminophenyl)-5-aminobenzimidazole to form an amide bond, thereby forming a main catalyst with a covalent porous structure. A large number of active sites such as nitrogen atoms exist on the triazine ring and the benzimidazole ring, which can effectively activate the oxidant, accelerate the oxidative desulfurization reaction of sulfide, and improve the desulfurization ability of the sulfide remover.

[0018] 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 amount of 4-dimethylaminopyridine is 3%-5% of the mass of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine; and the amount ratio of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine to dimethyl sulfoxide is 1 g:(13-15) mL.

[0019] By adopting the above technical solution, excessive amounts of N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine can easily lead to an increase in impurities in the reaction system, an increase in side reactions, and affect the structure and performance of the product. Excessive amounts of N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine can easily lead to incomplete reaction, affect the number of active sites of the main catalyst, and thus reduce the catalytic activity.

[0020] Preferably, the temperature-raising reaction steps are as follows: heating to 80-100° C. for the first time and reacting for 12-20 hours, heating to 100-120° C. for the second time and reacting for 24-36 hours, and heating to 120-130° C. for the third time and reacting for 45-48 hours.

[0021] By adopting the above technical solution, the three-stage temperature-raising reaction can better cross-link and arrange the molecular chains, forming a stable and regular three-dimensional structure, avoiding the problem of violent reaction and uneven cross-linking of molecular chains caused by rising to high temperature in one step.

[0022] Preferably, the preparation method of the cocatalyst comprises the following steps:

[0023] (1) Manganese nitrate, molecular sieve and anhydrous ethanol are uniformly mixed, impregnated, dried, oxidized and calcined to obtain porous manganese oxide;

[0024] (2) The porous manganese oxide, cobalt nitrate and anhydrous ethanol are uniformly mixed, impregnated, dried, and oxidized and calcined to obtain cobalt-modified porous manganese oxide;

[0025] (3) The cobalt-modified porous manganese oxide, heteropoly acid and water are uniformly mixed, impregnated, washed and dried to obtain a cocatalyst.

[0026] By adopting the above technical solution, the porous manganese oxide prepared in step (1) has a porous structure and a large specific surface area, which can provide more active sites and facilitate the rapid transmission of sulfide in the pores of the auxiliary catalyst; in step (2), the porous manganese oxide is cobalt-modified to improve the activity of the auxiliary catalyst; in step (3), the heteropoly acid 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 heteropoly acid can provide protons and electrons to promote the oxidation reaction of sulfide; at the same time, the heteropoly acid can further expand the pores of the cobalt-modified porous manganese oxide through electrostatic interaction, thereby improving the desulfurization efficiency.

[0027] Preferably, in step (1), the usage ratio of manganese nitrate, molecular sieve and anhydrous ethanol is 1 g: (0.65-0.8) g: (4-6) mL.

[0028] By adopting the above technical solution, within the dosage range, the porous manganese oxide has a rich pore structure and a large specific surface area.

[0029] Preferably, in step (1), the oxidation 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 hours.

[0030] Preferably, in step (2), the usage ratio of porous manganese oxide, cobalt nitrate and anhydrous ethanol is 1 g: (0.07-0.15) g: (5-7) mL.

[0031] By adopting the above technical solution, the introduction of cobalt can improve the structure of porous manganese oxide, increase the active sites on the catalyst surface, and at the same time enhance the structural stability of porous manganese oxide, so that it can maintain long-term stable catalytic performance; by adjusting the amount of cobalt, the catalyst performance can be optimized.

[0032] Preferably, in step (2), the oxidation 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 3-5h.

[0033] Preferably, in step (3), the ratio of the cobalt-modified porous manganese oxide, the heteropoly acid and water is 1 g: (2.5-3) g: (80-90) mL.

[0034] By adopting the above technical solution, the loading amount of heteropoly acid is moderate within the dosage range; too much heteropoly acid is likely to aggregate on the surface of cobalt-modified porous manganese oxide, resulting in uneven distribution of active sites and clogging of pores; too little heteropoly acid cannot fully adsorb and oxidize sulfides, and the desulfurization effect becomes poor.

[0035] The present invention also provides a method for preparing the above-mentioned environmentally friendly desulfurizer for oil and gas fields, comprising the following steps:

[0036] The main catalyst, auxiliary catalyst, diethanolamine, ethylenediaminetetraacetic acid, alkylphenol polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester, dispersant and water are uniformly mixed, and an oxidant is added and mixed uniformly to obtain an environmentally friendly sulfide remover for oil and gas fields.

[0037] In summary, the beneficial effects of the present invention are:

[0038] (1) The present invention compounds the oxidant, the main catalyst and the auxiliary catalyst with components such as polyoxyethylene sorbitan fatty acid ester and a dispersant, so that the environmentally friendly sulfide remover for oil and gas fields has good chemical stability and dispersibility, and has a high efficiency in removing both organic sulfur and inorganic sulfur;

[0039] (2) The present invention forms a main catalyst with a covalent porous structure through a condensation reaction between 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine and 2-(4-aminophenyl)-5-aminobenzimidazole. The presence of the triazine ring and the benzimidazole ring can provide a large number of nitrogen atom active sites, effectively activating the oxidant and improving the desulfurization ability of the sulfide remover.

[0040] (3) In the present invention, the heteropoly acid is loaded on the cobalt-modified porous manganese oxide. The 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 pores of the cobalt-modified porous manganese oxide through adsorption. At the same time, the heteropoly acid has a strong redox property and acts as an oxidation catalyst in the desulfurization process, further enhancing the ability to remove sulfides. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The H2S desulfurization rate results of the embodiment of the present invention and the comparative example are shown;

[0042] Figure 2 The DBT desulfurization rate results of the examples of the present invention and the comparative example are shown;

[0043] Figure 3 The pore size distribution diagram of the co-catalyst prepared in Example 1 of the present invention and Comparative Examples 4 and 5 is shown. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is explained in detail below with reference to several representative embodiments of the present invention.

[0045] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are all conventional methods. Unless otherwise specified, the materials, reagents, etc. used in the following examples and comparative examples are all commercially available.

[0046] The heteropoly acid used in the following examples and comparative examples is 12-molybdenum heteropoly acid hydrate.

[0047] Example 1

[0048] The environmentally friendly desulfurizer for oil and gas fields of this embodiment is composed of the following components:

[0049] 25g tert-butyl hydroperoxide, 10g main catalyst, 3g cocatalyst, 1g diethanolamine, 0.8g ethylenediaminetetraacetic acid, 3g alkylphenol polyoxyethylene ether, 0.7g polyoxyethylene sorbitan fatty acid ester, 2g sodium polyacrylate, 4g polyethylene glycol, 2g polyvinyl pyrrolidone, 48.5g water.

[0050] The preparation method of the environmentally friendly desulfurizer for oil and gas fields in this embodiment comprises the following specific steps:

[0051] 10 g of the main catalyst, 3 g of the co-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 polyvinyl pyrrolidone and 48.5 g of water were stirred for 30 minutes, 25 g of tert-butyl hydroperoxide was added and stirring was continued for 1 hour to obtain an environmentally friendly sulfide remover for oil and gas fields.

[0052] The preparation method of the main catalyst of this embodiment has the following specific steps:

[0053] 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 were added to a three-necked flask and stirred for 2 hours. The temperature was raised to 90°C for the first time to react for 20 hours, the temperature was raised to 110°C for the second time to react for 36 hours, and the temperature was raised to 125°C for the third time to react for 45 hours. The catalyst was washed with dilute hydrochloric acid, deionized water and acetone for 5 times respectively, and dried in a vacuum drying oven at 80°C for 12 hours to obtain the main catalyst.

[0054] The preparation method of the cocatalyst of this embodiment comprises the following specific steps:

[0055] (1) 5 g of manganese nitrate, 3.5 g of KIT-6 molecular sieve and 25 mL of anhydrous ethanol were added to a three-necked flask and stirred for 6 h. The mixture was placed in a vacuum drying oven at 70 °C and dried for 8 h. The mixture was transferred to a muffle furnace and heated to 500 °C at a heating rate of 5 °C / min under an oxygen atmosphere and calcined for 3 h. 2 g of the calcined product was added to 60 mL of a 2 mol / L sodium hydroxide aqueous solution, heated to 60 °C and stirred for 5 h. The mixture was washed with deionized water and dried in a vacuum drying oven at 60 °C for 8 h to obtain porous manganese oxide.

[0056] (2) 3 g of porous manganese oxide, 0.27 g of cobalt nitrate and 15 mL of anhydrous ethanol were added to a three-necked flask and stirred for 12 h. The mixture was dried in a vacuum drying oven at 70 °C for 10 h. The mixture was transferred to a muffle furnace and heated to 450 °C at a heating rate of 5 °C / min under an oxygen atmosphere and calcined for 5 h to obtain cobalt-modified porous manganese oxide.

[0057] (3) 1 g of cobalt-modified porous manganese oxide, 2.6 g of heteropoly acid and 90 mL of water were added to a three-necked flask and stirred for 36 h. The mixture was washed with deionized water and dried in a vacuum drying oven at 80 °C for 12 h to obtain a cocatalyst.

[0058] Example 2

[0059] The environmentally friendly desulfurizer for oil and gas fields of this embodiment is composed of the following components:

[0060] 18g tert-butyl hydroperoxide, 12g main catalyst, 2g cocatalyst, 4g diethanolamine, 0.5g ethylenediaminetetraacetic acid, 1g alkylphenol polyoxyethylene ether, 0.6g polyoxyethylene sorbitan fatty acid ester, 4g sodium polyacrylate, 4g polyethylene glycol, 2g polyvinyl pyrrolidone, 51.9g water.

[0061] The preparation method of the environmentally friendly desulfurizer for oil and gas fields in this embodiment comprises the following specific steps:

[0062] 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 polyvinyl pyrrolidone and 51.9 g of water were stirred for 30 minutes, 18 g of tert-butyl hydroperoxide was added and stirring was continued for 1 hour to obtain an environmentally friendly sulfide remover for oil and gas fields.

[0063] The preparation method of the main catalyst of this embodiment has the following specific steps:

[0064] 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 were added to a three-necked flask and stirred for 2 hours. The mixture was heated to 80°C for the first time and reacted for 16 hours, heated to 100°C for the second time and reacted for 28 hours, and heated to 120°C for the third time and reacted for 48 hours. The mixture was washed with dilute hydrochloric acid, deionized water and acetone for 5 times respectively, and dried in a vacuum drying oven at 80°C for 12 hours to obtain the main catalyst.

[0065] The preparation method of the cocatalyst of this embodiment comprises the following specific steps:

[0066] (1) 5 g of manganese nitrate, 3.25 g of KIT-6 molecular sieve and 20 mL of anhydrous ethanol were added to a three-necked flask and stirred for 6 h. The mixture was placed in a vacuum drying oven at 70 °C and dried for 8 h. The mixture was transferred to a muffle furnace and heated to 600 °C at a heating rate of 5 °C / min under an oxygen atmosphere and calcined for 4 h. 2 g of the calcined product was added to 60 mL of a 2 mol / L sodium hydroxide aqueous solution, heated to 60 °C and stirred for 5 h. The mixture was washed with deionized water and dried in a vacuum drying oven at 60 °C for 8 h to obtain porous manganese oxide.

[0067] (2) 3 g of porous manganese oxide, 0.36 g of cobalt nitrate and 18 mL of anhydrous ethanol were added to a three-necked flask and stirred for 12 h. The mixture was dried in a vacuum drying oven at 70 °C for 10 h. The mixture was transferred to a muffle furnace and heated to 400 °C at a heating rate of 5 °C / min under an oxygen atmosphere and calcined for 3 h to obtain cobalt-modified porous manganese oxide.

[0068] (3) 1 g of cobalt-modified porous manganese oxide, 2.5 g of heteropoly acid and 85 mL of water were added to a three-necked flask and stirred for 36 h. The mixture was washed with deionized water and dried in a vacuum drying oven at 80 °C for 12 h to obtain a cocatalyst.

[0069] Example 3

[0070] The environmentally friendly desulfurizer for oil and gas fields of this embodiment is composed of the following components:

[0071] 30g hydrogen peroxide, 8g main catalyst, 3g cocatalyst, 3g diethanolamine, 1g ethylenediaminetetraacetic acid, 2g alkylphenol polyoxyethylene ether, 0.5g polyoxyethylene sorbitan fatty acid ester, 4g sodium polyacrylate, 1g polyethylene glycol, 1g polyvinyl pyrrolidone, 48.5g water.

[0072] The preparation method of the environmentally friendly desulfurizer for oil and gas fields in this embodiment comprises the following specific steps:

[0073] 8 g of the main catalyst, 3 g of the 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 polyvinyl pyrrolidone and 48.5 g of water were stirred for 30 minutes, 30 g of hydrogen peroxide was added and stirring was continued for 1 hour to obtain an environmentally friendly sulfide remover for oil and gas fields.

[0074] The preparation method of the main catalyst of this embodiment has the following specific steps:

[0075] 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 were added to a three-necked flask and stirred for 2 hours. The temperature was raised to 100°C for the first reaction and the reaction was carried out for 12 hours. The temperature was raised to 120°C for the second reaction and the reaction was carried out for 24 hours. The temperature was raised to 130°C for the third reaction and the reaction was carried out for 46 hours. The catalyst was washed with dilute hydrochloric acid, deionized water and acetone for 5 times respectively, and dried in a vacuum drying oven at 80°C for 12 hours to obtain the main catalyst.

[0076] The preparation method of the cocatalyst of this embodiment comprises the following specific steps:

[0077] (1) 5 g of manganese nitrate, 4 g of KIT-6 molecular sieve and 30 mL of anhydrous ethanol were added to a three-necked flask and stirred for 6 h. The mixture was placed in a vacuum drying oven at 70 °C and dried for 8 h. The mixture was transferred to a muffle furnace and heated to 540 °C at a heating rate of 5 °C / min under an oxygen atmosphere and calcined for 2 h. 2 g of the calcined product was added to 60 mL of a 2 mol / L sodium hydroxide aqueous solution, heated to 60 °C and stirred for 5 h. The mixture was washed with deionized water and dried in a vacuum drying oven at 60 °C for 8 h to obtain porous manganese oxide.

[0078] (2) 3 g of porous manganese oxide, 0.21 g of cobalt nitrate and 21 mL of anhydrous ethanol were added to a three-necked flask and stirred for 12 h. The mixture was dried in a vacuum drying oven at 70 °C for 10 h. The mixture was transferred to a muffle furnace and heated to 500 °C at a heating rate of 5 °C / min under an oxygen atmosphere and calcined for 4 h to obtain cobalt-modified porous manganese oxide.

[0079] (3) 1 g of cobalt-modified porous manganese oxide, 2.8 g of heteropoly acid and 90 mL of water were added to a three-necked flask and stirred for 36 h. The mixture was washed with deionized water and dried in a vacuum drying oven at 80 °C for 12 h to obtain a cocatalyst.

[0080] Example 4

[0081] The environmentally friendly desulfurizer for oil and gas fields of this embodiment is composed of the following components:

[0082] 22g hydrogen peroxide, 10g main catalyst, 4g cocatalyst, 3g diethanolamine, 1g ethylenediaminetetraacetic acid, 2g alkylphenol polyoxyethylene ether, 0.8g polyoxyethylene sorbitan fatty acid ester, 2g sodium polyacrylate, 2g polyethylene glycol, 2g polyvinyl pyrrolidone, 51.2g water.

[0083] The preparation method of the environmentally friendly desulfurizer for oil and gas fields in this embodiment comprises the following specific steps:

[0084] 10 g of the main catalyst, 4 g of the 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 polyvinyl pyrrolidone and 51.2 g of water were stirred for 30 minutes, 22 g of hydrogen peroxide was added and stirring was continued for 1 hour to obtain an environmentally friendly sulfide remover for oil and gas fields.

[0085] The preparation method of the main catalyst of this embodiment has the following specific steps:

[0086] 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 hours. The mixture was heated to 90°C for the first time and reacted for 14 hours, then heated to 115°C for the second time and reacted for 30 hours, and finally heated to 130°C for the third time and reacted for 48 hours. The mixture was washed with dilute hydrochloric acid, deionized water and acetone for 5 times respectively, and dried in a vacuum drying oven at 80°C for 12 hours to obtain the main catalyst.

[0087] The preparation method of the cocatalyst of this embodiment comprises the following specific steps:

[0088] (1) 5 g of manganese nitrate, 3.75 g of KIT-6 molecular sieve and 30 mL of anhydrous ethanol were added to a three-necked flask and stirred for 6 h. The mixture was placed in a vacuum drying oven at 70 °C and dried for 8 h. The mixture was transferred to a muffle furnace and heated to 580 °C at a heating rate of 5 °C / min under an oxygen atmosphere and calcined for 4 h. 2 g of the calcined product was added to 60 mL of a 2 mol / L sodium hydroxide aqueous solution, heated to 60 °C and stirred for 5 h. The mixture was washed with deionized water and dried in a vacuum drying oven at 60 °C for 8 h to obtain porous manganese oxide.

[0089] (2) 3 g of porous manganese oxide, 0.45 g of cobalt nitrate and 21 mL of anhydrous ethanol were added to a three-necked flask and stirred for 12 h. The mixture was dried in a vacuum drying oven at 70 °C for 10 h. The mixture was transferred to a muffle furnace and heated to 480 °C at a heating rate of 5 °C / min under an oxygen atmosphere and calcined for 4 h to obtain cobalt-modified porous manganese oxide.

[0090] (3) 1 g of cobalt-modified porous manganese oxide, 3 g of heteropoly acid and 80 mL of water were added to a three-necked flask and stirred for 36 h. The mixture was washed with deionized water and dried in a vacuum drying oven at 80 °C for 12 h to obtain a cocatalyst.

[0091] Comparative Example 1-Comparative Example 3

[0092] The difference from Example 1 is that the environmentally friendly sulfide removers for oil and gas fields prepared in Comparative Examples 1 to 3 are composed of the components in Table 1, and the rest are the same as in Example 1.

[0093] Table 1 Components of environmentally friendly sulfide removers for oil and gas fields

[0094]

[0095] Comparative Example 4

[0096] The difference from Example 1 is that the preparation of the cocatalyst in this comparative example does not include step (2) and step (3), and the rest is the same as Example 1.

[0097] Comparative Example 5

[0098] The difference from Example 1 is that the preparation of the cocatalyst in this comparative example does not include the preparation of step (3), and the rest is the same as Example 1.

[0099] Comparative Example 6

[0100] 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.

[0101] Comparative Example 7

[0102] 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.

[0103] Comparative Example 8

[0104] 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.

[0105] Related performance tests

[0106] 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.

[0107] Combine Figure 1 and Figure 2 We can get:

[0108] 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.

[0109] 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.

[0110] 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.

[0111] From the comparison between Comparative Example 7 and Example 1, it can be seen that too much 2-(4-aminophenyl)-5-aminobenzimidazole may cause disorder inside the main catalyst and reduce the sulfide removal rate.

[0112] From the comparison between Comparative Example 8 and Example 1, it can be seen that the introduction of the benzimidazole ring has a greater impact on the organic sulfur of DBT; the nitrogen atom on the benzimidazole ring has a lone pair of electrons, and the entire ring has a certain conjugated system, which can activate oxidants such as tert-butyl hydroperoxide and improve the desulfurization rate.

[0113] The above is 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 other equivalent replacement that can be made by other skilled in the art without expending creative labor shall fall within the scope of protection of the present invention.

Claims

1. An environmentally friendly sulfide remover for oil and gas fields, characterized in that: It is composed of the following components in percentage by mass: 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); The preparation method of the cocatalyst comprises the following steps: (1) Manganese nitrate, molecular sieve and anhydrous ethanol are uniformly mixed, impregnated, dried, oxidized and calcined to obtain porous manganese oxide; (2) The porous manganese oxide, cobalt nitrate and anhydrous ethanol are uniformly mixed, impregnated, dried, and oxidized and calcined to obtain cobalt-modified porous manganese oxide; (3) The cobalt-modified porous manganese oxide, heteropoly acid and water are uniformly mixed, impregnated, washed and dried to obtain a cocatalyst.

2. The environmentally friendly desulfurizer for oil and gas fields according to claim 1, characterized in that: The oxidant is selected from one of hydrogen peroxide and tert-butyl hydroperoxide.

3. The environmentally friendly desulfurizer for oil and gas fields according to claim 1, characterized in that: The dispersant is prepared by mixing sodium polyacrylate, polyethylene glycol and polyvinyl pyrrolidone in a mass ratio of (1-3): (1-2):

1.

4. The environmentally friendly desulfurizer for oil and gas fields according to claim 1, characterized in that: The preparation method of the main catalyst comprises the following steps: 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 2-(4-aminophenyl)-5-aminobenzimidazole, N,N'-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and dimethyl sulfoxide are uniformly mixed, heated for reaction, washed and dried to obtain a main catalyst.

5. The environmentally friendly desulfurizer for oil and gas fields according to claim 4, characterized in that: 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 amount of 4-dimethylaminopyridine used is 3%-5% of the mass of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine; and the amount ratio of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine to dimethyl sulfoxide is 1 g:(13-15) mL.

6. The environmentally friendly desulfurizer for oil and gas fields according to claim 4, characterized in that: The specific steps of the temperature reaction are as follows: heating to 80-100° C. for the first time and reacting for 12-20 hours, heating to 100-120° C. for the second time and reacting for 24-36 hours, and heating to 120-130° C. for the third time and reacting for 45-48 hours.

7. The environmentally friendly desulfurizer for oil and gas fields according to claim 1, characterized in that: In the step (1), the usage ratio of manganese nitrate, molecular sieve and anhydrous ethanol is 1 g: (0.65-0.8) g: (4-6) mL.

8. The environmentally friendly desulfurizer for oil and gas fields according to claim 1, characterized in that: In the step (2), the usage ratio of porous manganese oxide, cobalt nitrate and anhydrous ethanol is 1 g: (0.07-0.15) g: (5-7) mL.

9. The environmentally friendly desulfurizer for oil and gas fields according to claim 1, characterized in that: In the step (3), the ratio of the cobalt-modified porous manganese oxide, the heteropoly acid and water is 1 g: (2.5-3) g: (80-90) mL.

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