A desulfurizing agent for acidic sulfur-containing wastewater, its preparation method and desulfurization method

Abstract

This invention relates to a desulfurizing agent for treating acidic sulfur-containing wastewater, its preparation method, and the desulfurization method thereof. The acidic desulfurizing agent achieves a 100% desulfurization efficiency for sulfur-containing wastewater with a sulfide content of 500 mg / L at 50°C. The treated wastewater exhibits a corrosion rate of less than 6 g / (m²) on N80 steel sheets at 90°C. 2 (h). Based on a total mass of 100wt% of the desulfurizing agent, the content of strong oxidant is 25wt%-60wt%, the content of thickener (based on solids) is 0.1wt%-5.5wt%, the content of corrosion inhibitor is 0.1wt%-4wt%, the content of stabilizer is 0.1wt%-4wt%, and the content of reaction promoter is 0.5wt%-4wt%. This invention is a desulfurizing agent that can be directly used in acidic sulfur-containing wastewater. This desulfurizing agent has stable performance, low operational risk, convenient dosing, high desulfurization efficiency, is not easily decomposed, produces no precipitate of reaction products, has strong practicality, and good application prospects.

Description

Technical Field

[0001] This invention relates to desulfurizing agents for acidic sulfur-containing wastewater, their preparation methods, and desulfurization methods. Background Technology

[0002] Marine formation acid fracturing flowback fluids contain hydrogen sulfide, with concentrations reaching up to 1000 ppm. Sulfur-containing wastewater not only causes corrosion of equipment and pipelines, but also poses a significant safety hazard to on-site workers and residents in the densely populated marine areas of western Sichuan. Without desulfurization, there are substantial safety risks during wastewater transfer and treatment. Developing efficient desulfurizing agents has become a crucial safety and environmental issue that oilfield enterprises urgently need to address for sustainable development.

[0003] According to patent 201210177844.4, current methods for liquid desulfurization mainly fall into two categories: liquid absorption and oxidation. The main reagents used in liquid absorption are triazine derivatives, alkanolamine compounds, and pyridine compounds, all of which are alkaline desulfurizing agents. These agents are characterized by simple synthesis, low cost, low toxicity, and biodegradability, and can be directly injected into oil and gas pipelines for liquid desulfurization. However, alkaline desulfurizing agents are limited to use in alkaline environments; under acidic conditions, they will undergo hydrolysis and decompose, losing their effectiveness. In previous desulfurization operations in marine gas fields, to treat sulfur-containing wastewater, it was necessary to first add alkali solution for neutralization before adding desulfurizing agent for desulfurization. This procedure was complex. Furthermore, hydroxide ions in the alkali solution would react with calcium and magnesium ions in the formation water to form precipitates, clogging production pipelines and affecting the normal drainage of gas wells. The main reagent used in the oxidation method is hydrogen peroxide. Hydrogen peroxide with a concentration of more than 50% will decompose at high temperatures, producing oxygen and water, and losing its oxidizing effect. Moreover, high concentrations of hydrogen peroxide can also cause explosions under impact, heat or sparks, posing a significant safety hazard.

[0004] In summary, there is currently no acid desulfurizing agent product that can be used directly under acidic conditions while simultaneously possessing low risk, high desulfurization efficiency, and no impact on marine gas well testing and flowback. Summary of the Invention

[0005] The inventors of this invention have discovered that the main agent in traditional desulfurizing agents is hydrogen peroxide, which is easily volatilized and decomposed at high temperatures, resulting in poor oxidation effects. Therefore, to address the shortcomings of the prior art, this invention provides a desulfurizing agent, its preparation method, and a desulfurization method using the aforementioned desulfurizing agent. By introducing a thickening agent into the desulfurizing agent, the volatilization of hydrogen peroxide during the desulfurization process can be prevented, improving the stability of the desulfurizing agent throughout the entire desulfurization process. The thickening agent is also less prone to decomposition under acidic conditions and strong oxidizing agents.

[0006] This invention is primarily used to remove sulfides from sulfur-containing wastewater. Through the combined action of hydrogen peroxide, a thickener, an acid stabilizer, and a reaction promoter, the strong oxidant maintains stable performance, is not prone to volatilization or explosion, and can rapidly and efficiently oxidize sulfides in water. Simultaneously, the added corrosion inhibitor slows down corrosion, solving the pipeline corrosion and safety / environmental problems caused by hydrogen sulfide gas during test runbacks from marine gas wells. It also addresses the issues of desulfurizing agents being unusable under acidic conditions, having high operational risks, and being prone to decomposition and having poor stability. Compared to existing desulfurizing agents, the acidic desulfurizing agent developed in this invention offers high desulfurization efficiency (up to 100%), low pipeline corrosion rate, and can be directly injected into pipelines, thus solving the difficult problem of treating sulfur-containing wastewater from oil and gas wells. Detailed Implementation

[0007] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0008] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0009] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0010] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this instruction manual are based on weight, and the pressure is gauge pressure.

[0011] In the context of this specification, any two or more embodiments of the present invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0012] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0013] In the context of this specification, pH values ​​are measured using pH test strips or a pH meter.

[0014] The technical solution adopted by this invention to achieve its technical objective is to provide a desulfurizing agent suitable for acidic sulfur-containing wastewater, comprising a strong oxidant, a thickener, a corrosion inhibitor, a stabilizer, and a reaction promoter. Based on 100wt% of the total mass of the desulfurizing agent, the content of the strong oxidant is 25wt%-60wt% (preferably 40wt%-50wt%), the content of the thickener (based on solids) is 0.1wt%-5.5wt% (preferably 0.5wt%-1.5wt%), the content of the corrosion inhibitor is 0.1wt%-4wt% (preferably 0.5wt%-2wt%), the content of the stabilizer is 0.1wt%-4wt% (preferably 0.5wt%-2wt%), and the content of the reaction promoter is 0.5wt%-4wt% (preferably 1wt%-2wt%). This acidic desulfurizing agent system exhibits good stability in the operating environment, low construction risk, and achieves 100% desulfurization efficiency for sulfur-containing wastewater.

[0015] As one preferred embodiment, the total mass of the acidic desulfurizing agent system is 100 wt%, and the composition of the remaining raw materials is calculated according to the following weight ratios:

[0016]

[0017] As one of the preferred options, the strong oxidant is an aqueous solution of hydrogen peroxide.

[0018] As one preferred embodiment, the concentration of the hydrogen peroxide aqueous solution is 40wt%-50wt%.

[0019] As one of the preferred options, the corrosion inhibitor is selected from at least one of propynyl alcohol corrosion inhibitors, organic amine corrosion inhibitors, imidazoline corrosion inhibitors, and quaternary ammonium salt corrosion inhibitors, preferably selected from at least one of imidazoline corrosion inhibitors and quaternary ammonium salt corrosion inhibitors, and more preferably imidazoline quaternary ammonium salts.

[0020] As one of the preferred options, the corrosion inhibitor is dodecyl imidazoline.

[0021] As one of the preferred options, the stabilizer is selected from at least one of phosphoric acid and its derivatives, polyphosphoric acid and its derivatives, carboxylic acid and its derivatives, polycarboxylic acid and its derivatives, and boric acid and its derivatives, preferably selected from at least one of phosphoric acid and its derivatives, and more preferably orthophosphoric acid.

[0022] As one preferred embodiment, the tackifier is selected from at least one of C8-30 alkyl di(C1-10 alkyl)amine oxides, preferably from at least one of C12-18 alkyl di(C1-4 alkyl)amine oxides, and more preferably from at least one of dodecyl dimethylamine oxide and tetradecyl dimethylamine oxide. As one preferred embodiment, the reaction promoter is selected from at least one of polyacrylamides, preferably from at least one of compounds in which some or all of the hydrogen atoms on the nitrogen of a C2-20 polyamine (preferably a C2-10 diamine) are replaced by a C1-10 alkyl carbonyl group (preferably a C1-4 alkyl carbonyl group), and more preferably tetraacetylethylenediamine.

[0023] As one of the preferred embodiments, the mass ratio of the strong oxidant (based on the effective ingredient) to the thickener (based on the solid content) is 30:1 to 50:1 (preferably 35:1 to 45:1).

[0024] As one of the preferred options, the desulfurizing agent has a pH value of 3-4.

[0025] The acidic desulfurizing agent of this invention achieves a 100% desulfurization efficiency for sulfur-containing wastewater with a sulfide content of 500 mg / L at 50°C, and the treated wastewater has a corrosion rate of less than 6 g / (m2·h) on steel sheets at 90°C.

[0026] The present invention also relates to a method for preparing an acidic desulfurizing agent system, comprising the steps of sequentially adding the reaction promoter and the thickener to the strong oxidant.

[0027] As one of the preferred embodiments, the preparation method of the present invention includes the following steps:

[0028] Step 1. Weigh each ingredient according to the formula.

[0029] Step 2. Stir the strong oxidizing agent;

[0030] Step 3. While stirring, add the stabilizer to the liquid from Step 2 to obtain a homogeneous liquid;

[0031] Step 4. While stirring, add corrosion inhibitor to the liquid from Step 3 to obtain a homogeneous liquid;

[0032] Step 5. While stirring, add the reaction promoter to the liquid from Step 4 to obtain a homogeneous liquid;

[0033] Step 6. While maintaining stirring, add the thickener to the liquid from Step 5 and stir until homogeneous to obtain the desulfurizing agent.

[0034] Furthermore, the present invention relates to a method for desulfurizing acidic sulfur-containing wastewater, comprising the step of adding the desulfurizing agent described in the present invention to the acidic sulfur-containing wastewater to remove sulfides from the acidic sulfur-containing wastewater (referred to as the desulfurization step).

[0035] As one of the preferred embodiments, the desulfurization step is carried out at 40-80°C, and the amount of the desulfurizing agent used is 2-10 parts by weight (preferably 4-6 parts by weight) relative to 100 parts by weight of the acidic sulfur-containing wastewater.

[0036] The present invention also relates to a desulfurization method, wherein in the desulfurization step, the desulfurizing agent of the present invention is directly injected into an oil and gas pipeline to remove sulfides from the acidic sulfur-containing wastewater.

[0037] Example

[0038] The present invention will be further described in detail below through embodiments and comparative examples, but the present invention is not limited to the following embodiments.

[0039] Example 1

[0040] The strong oxidant used in this embodiment is hydrogen peroxide with an effective content of 60%.

[0041] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 2g of dodecyl imidazoline, 2g of phosphoric acid, and 1.5g of tetradecyl dimethylamine oxide, and set aside for later use.

[0042] Step 2: Stir the hydrogen peroxide solution;

[0043] Step 3: While keeping the mixture stirred, add 2g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0044] Step 4: While keeping the mixture stirred, add 2g of phosphoric acid to the base solution prepared in step 3 and stir until a homogeneous solution is formed.

[0045] Step 5: Reduce the stirring speed and add 2g of tetraacetylethylenediamine to the base solution prepared in step 4.

[0046] Step 6: Reduce the stirring speed, add 1.5g of tetradecyl dimethylamine oxide to the base solution prepared in step 5, and stir to form a uniform solution to obtain the desulfurizing agent system for treating sulfur-containing wastewater.

[0047] The pH value of the desulfurizing agent is 3-4.

[0048] Example 2

[0049] The strong oxidant used in this embodiment is hydrogen peroxide with an effective content of 55%.

[0050] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 1.5g of dodecyl imidazoline, 2g of phosphoric acid, and 1.5g of tetradecyl dimethylamine oxide, and set aside for later use.

[0051] Step 2: Stir the hydrogen peroxide solution;

[0052] Step 3: While keeping the mixture stirred, add 1.5g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0053] Step 4: While maintaining stirring, add 2g of phosphoric acid to the base solution prepared in step 3, and stir until a homogeneous solution is formed.

[0054] Step 5: Reduce the stirring speed and add 2g of tetraacetylethylenediamine to the base solution prepared in step 4.

[0055] Step 6: Reduce the stirring speed, add 1.5g of tetradecyl dimethylamine oxide to the base solution prepared in step 5, and stir to form a uniform solution to obtain the desulfurizing agent system for treating sulfur-containing wastewater.

[0056] The pH value of the desulfurizing agent is 3-4.

[0057] Example 3

[0058] The strong oxidant used in this embodiment is hydrogen peroxide with an effective content of 50%.

[0059] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 1g of dodecyl imidazoline, 1.5g of phosphoric acid, and 1g of tetradecyl dimethylamine oxide, and set aside for later use.

[0060] Step 2: Stir the hydrogen peroxide solution;

[0061] Step 3: While keeping the mixture stirred, add 1g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0062] Step 4: While maintaining stirring, add 1.5g of phosphoric acid to the base solution prepared in step 3, and stir until a homogeneous solution is formed.

[0063] Step 5: Reduce the stirring speed and add 1.5g of tetraacetylethylenediamine to the base solution prepared in step 4.

[0064] Step 6: Reduce the stirring speed, add 1g of tetradecyl dimethylamine oxide to the base solution prepared in step 5, and stir to form a uniform solution to obtain the desulfurizing agent system for treating sulfur-containing wastewater.

[0065] The pH value of the desulfurizing agent is 3-4.

[0066] Example 4

[0067] The strong oxidant used in this embodiment is hydrogen peroxide with an effective content of 45%.

[0068] The preparation method of the acidic desulfurizing agent for treating sulfur-containing wastewater is as follows:

[0069] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 1g of dodecyl imidazoline, 1g of orthophosphoric acid, and 0.5g of tetradecyl dimethylamine oxide, and set aside for later use.

[0070] Step 2: Stir the hydrogen peroxide solution;

[0071] Step 3: While keeping the mixture stirred, add 1g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0072] Step 4: While maintaining stirring, add 1g of phosphoric acid to the base solution prepared in step 3, and stir until a homogeneous solution is formed.

[0073] Step 5: Reduce the stirring speed and add 1g of tetraacetylethylenediamine to the base solution prepared in step 4.

[0074] Step 6: Reduce the stirring speed, add 0.5g of tetradecyl dimethylamine oxide to the base solution prepared in step 5, and stir to form a uniform solution to obtain the desulfurization agent system for treating sulfur-containing wastewater.

[0075] The pH value of the desulfurizing agent is 3-4.

[0076] Example 5

[0077] The strong oxidant used in this embodiment is 40% hydrogen peroxide.

[0078] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 1g of dodecyl imidazoline, 0.5g of phosphoric acid, and 0.5g of dodecyl dimethylamine oxide, and set aside for later use.

[0079] Step 2: Stir the hydrogen peroxide solution;

[0080] Step 3: While keeping the mixture stirred, add 1g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0081] Step 4: While keeping the mixture stirred, add 0.5g of sodium nitrate to the base solution prepared in step 3 and stir until a homogeneous solution is formed;

[0082] Step 5: Reduce the stirring speed and add 1g of tetraacetylethylenediamine to the base solution prepared in step 4.

[0083] Step 6: Reduce the stirring speed, add 0.55g tetradecyl dimethylamine oxide to the base solution prepared in step 5, and stir to form a uniform solution to obtain the desulfurization agent system for treating sulfur-containing wastewater.

[0084] The pH value of the desulfurizing agent is 3-4.

[0085] Example 6

[0086] The strong oxidant used in this embodiment is 35% hydrogen peroxide.

[0087] The preparation method of the acidic desulfurizing agent for treating sulfur-containing wastewater is as follows:

[0088] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 0.5g of dodecyl imidazoline, 0.5g of phosphoric acid, and 0.5g of dodecyl dimethylamine oxide, and set aside for later use.

[0089] Step 2: Stir the hydrogen peroxide solution;

[0090] Step 3: While keeping the mixture stirred, add 0.5g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0091] Step 4: While keeping the mixture stirred, add 0.5g of sodium nitrate to the base solution prepared in step 3 and stir until a homogeneous solution is formed;

[0092] Step 5: Reduce the stirring speed and add 1g of tetraacetylethylenediamine to the base solution prepared in step 4.

[0093] Step 6: Reduce the stirring speed, add 0.5g of tetradecyl dimethylamine oxide to the base solution prepared in step 5, and stir to form a uniform solution to obtain the desulfurization agent system for treating sulfur-containing wastewater.

[0094] The pH value of the desulfurizing agent is 3-4.

[0095] Example 7

[0096] The strong oxidant used in this embodiment is 30% hydrogen peroxide.

[0097] The preparation method of the acidic desulfurizing agent for treating sulfur-containing wastewater is as follows:

[0098] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 0.5g of dodecyl imidazoline, 0.5g of sodium nitrate, and 0.5g of dodecyl dimethylamine oxide, and set aside for later use.

[0099] Step 2: Stir the hydrogen peroxide solution;

[0100] Step 3: While keeping the mixture stirred, add 0.5g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0101] Step 4: While keeping the mixture stirred, add 0.5g of sodium nitrate to the base solution prepared in step 3 and stir until a homogeneous solution is formed;

[0102] Step 5: Reduce the stirring speed and add 1g of tetraacetylethylenediamine to the base solution prepared in step 4.

[0103] Step 6: Reduce the stirring speed, add 0.5g of dodecyl dimethylamine oxide to the base solution prepared in step 5, and stir to form a uniform solution to obtain the desulfurization agent system for treating sulfur-containing wastewater.

[0104] The pH value of the desulfurizing agent is 3-4.

[0105] Example 8

[0106] The strong oxidant used in this embodiment is hydrogen peroxide with an effective content of 25%.

[0107] The preparation method of the acidic desulfurizing agent for treating sulfur-containing wastewater is as follows:

[0108] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 0.5g of dodecyl imidazoline, 0.5g of sodium nitrate, and 0.5g of dodecyl dimethylamine oxide, and set aside for later use.

[0109] Step 2: Stir the hydrogen peroxide solution;

[0110] Step 3: While keeping the mixture stirred, add 0.5g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0111] Step 4: While keeping the mixture stirred, add 0.5g of sodium nitrate to the base solution prepared in step 3 and stir until a homogeneous solution is formed;

[0112] Step 5: Reduce the stirring speed and add 1g of tetraacetylethylenediamine to the base solution prepared in step 4.

[0113] Step 6: Reduce the stirring speed, add 1.5g of dodecyl dimethylamine oxide to the base solution prepared in step 5, and stir to form a uniform solution to obtain the desulfurizing agent system for treating sulfur-containing wastewater.

[0114] The pH value of the desulfurizing agent is 3-4.

[0115] Comparative Example 1

[0116] The strong oxidant used in this embodiment is 50% hydrogen peroxide.

[0117] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 2g of dodecyl imidazoline, 2g of phosphoric acid, and 2g of tetraacetyl ethylenediamine for later use.

[0118] Step 2: Stir the hydrogen peroxide solution;

[0119] Step 3: While keeping the mixture stirred, add 2g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0120] Step 4: While keeping the mixture stirred, add 2g of phosphoric acid to the base solution prepared in step 3 and stir until a homogeneous solution is formed.

[0121] Step 5: Reduce the stirring speed, add 2g of tetraacetylethylenediamine to the base solution prepared in step 4, and stir to form a uniform solution to obtain the desulfurization agent system for treating sulfur-containing wastewater.

[0122] The pH value of the desulfurizing agent is 3-4.

[0123] Comparative Example 2

[0124] The strong oxidant used in this embodiment is 50% hydrogen peroxide.

[0125] Step 1. Accurately weigh 100g of hydrogen peroxide solution, 1.5g of dodecyl imidazoline, 2g of phosphoric acid, and 2g of tetraacetyl ethylenediamine for later use.

[0126] Step 2: Stir the hydrogen peroxide solution;

[0127] Step 3: While keeping the mixture stirred, add 1.5g of dodecyl imidazoline to the base solution prepared in step 2 and stir until a homogeneous solution is formed;

[0128] Step 4: While maintaining stirring, add 2g of phosphoric acid to the base solution prepared in step 3, and stir until a homogeneous solution is formed.

[0129] Step 5: Reduce the stirring speed, add 2g of tetraacetylethylenediamine to the base solution prepared in step 4, and stir to form a uniform solution to obtain the desulfurization agent system for treating sulfur-containing wastewater.

[0130] The pH value of the desulfurizing agent is 3-4.

[0131] Prepare sulfur-containing wastewater (sulfide concentration of about 500 mg / L) for on-site return discharge. Conduct desulfurization efficiency experiments on the acidic desulfurizing agent systems prepared in the above examples according to the following methods. The specific experimental conditions and requirements are as follows, and the results are shown in Table 1.

[0132] 1) Connect the apparatus: Connect the outlet pipe of the nitrogen cylinder to a wide-mouth bottle containing sulfur-containing wastewater via a flow meter. A magnetic stirrer is installed under the wide-mouth bottle. Place the wide-mouth bottle in a water bath. Connect the constant-pressure separating funnel of the desulfurizing agent addition device to the wide-mouth bottle. The outlet pipe of the wide-mouth bottle is connected to a hydrogen sulfide detector. Control the water bath temperature at 50℃. The entire operation should be performed in a fume hood. 2) After the experiment begins, turn on the nitrogen cylinder valve. Control the nitrogen flow rate to 0.2-2 L / min using the flow meter. Open the constant-pressure separating funnel and control the desulfurizing agent addition rate to 20-30 d / min. Simultaneously, turn on the magnetic stirrer to stir the sulfur-containing solution. 3) To determine the desulfurization efficiency, stop adding the desulfurizing agent and turn off the nitrogen cylinder valve when the outlet hydrogen sulfide detector reading reaches 0 ppm. 4) Use a flow meter to determine the sulfide content in the sulfur-containing solution.

[0133] Desulfurization efficiency (%) of desulfurizing agent = (amount of sulfides in the original sulfur-containing wastewater - remaining sulfur content) / amount of sulfides in the original sulfur-containing wastewater × 100%.

[0134] According to the testing method of the technical specification for acid materials in Q / SH1500 0030-2019, corrosion rate tests were conducted on steel sheets (N80) in sulfur-containing wastewater after the addition of desulfurizing agent at 90℃ for 4 hours. The results are shown in Table 1.

[0135] Table 1 Evaluation of desulfurization efficiency and corrosion rate

[0136]

[0137] As shown in Table 1, the compositions prepared in the above embodiments of the present invention can achieve a 100% desulfurization efficiency for sulfur-containing wastewater with a sulfide content of 500 mg / L at 50°C; and the corrosion rate of steel sheets (N80) at 90°C for 4 hours is less than 6 g / (m²). 2 h). Due to the synergistic effect between the components, the composition of the present invention exhibits significant changes in both desulfurization efficiency and corrosion inhibition effect on sulfur-containing wastewater. By reducing the dosage and type of reagent, its desulfurization efficiency is significantly reduced.

[0138] The above embodiments are only used to illustrate the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still modify the specific technical solutions in the above embodiments or make equivalent substitutions for some of the technical features, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the present invention.

Claims

1. A desulfurizing agent suitable for acidic sulfur-containing wastewater, comprising a strong oxidant, a thickener, a corrosion inhibitor, a stabilizer, and a reaction promoter, wherein, based on 100 wt% of the total mass of the desulfurizing agent, the content of the strong oxidant is 25 wt%-60 wt%, the content of the thickener (based on solids) is 0.1 wt%-5.5 wt%, the content of the corrosion inhibitor is 0.1 wt%-4 wt%, the content of the stabilizer is 0.1 wt%-4 wt%, and the content of the reaction promoter is 0.5 wt%-4 wt%. in, The strong oxidant is an aqueous solution of hydrogen peroxide; the thickener is selected from at least one of C8-30 alkyl di(C1-10 alkyl)amine oxides; the reaction promoter is selected from at least one of compounds in which some or all of the hydrogen atoms on the nitrogen of a C2-10 diamine are replaced by C1-4 alkyl carbonyl groups; the corrosion inhibitor is selected from at least one of propynyl alcohol corrosion inhibitors, organic amine corrosion inhibitors, imidazoline corrosion inhibitors, and quaternary ammonium salt corrosion inhibitors; and the stabilizer is selected from at least one of phosphoric acid and its derivatives, polyphosphoric acid and its derivatives, carboxylic acid and its derivatives, polycarboxylic acid and its derivatives, and boric acid and its derivatives.

2. The desulfurizing agent according to claim 1, characterized in that, Based on a total mass of 100wt% for the desulfurizing agent, the content of strong oxidant is 40wt%-50wt%, the content of thickener (based on solids) is 0.5wt%-1.5wt%, the content of corrosion inhibitor is 0.5wt%-2wt%, the content of stabilizer is 0.5wt%-2wt%, and the content of reaction promoter is 1wt%-2wt%.

3. The desulfurizing agent according to claim 1, characterized in that, The strong oxidant is a 40wt%-50wt% aqueous solution of hydrogen peroxide.

4. The desulfurizing agent according to claim 1, characterized in that, The thickener is selected from at least one of dodecyl dimethylamine oxide and tetradecyl dimethylamine oxide.

5. The desulfurizing agent according to claim 1, characterized in that, The reaction promoter is tetraacetylethylenediamine.

6. The desulfurizing agent according to claim 1, characterized in that, The mass ratio of the strong oxidant (based on the effective ingredient) to the thickener (based on the solid content) is 30:1 to 50:

1.

7. The desulfurizing agent according to claim 1, characterized in that, The mass ratio of the strong oxidant (based on the active ingredient) to the thickener (based on the solid content) is 35:1-45:

1.

8. The desulfurizing agent according to claim 1, characterized in that, The desulfurizing agent has a pH value of 3-4.

9. The desulfurizing agent according to claim 1, characterized in that, The corrosion inhibitor is selected from at least one of imidazoline corrosion inhibitors and quaternary ammonium salt corrosion inhibitors.

10. The desulfurizing agent according to claim 1, characterized in that, The stabilizer is selected from at least one of phosphoric acid and its derivatives.

11. The desulfurizing agent according to claim 1, characterized in that, The desulfurization efficiency of sulfur-containing wastewater with a sulfide content of 500 mg / L reached 100% at 50℃, and the corrosion rate of the treated wastewater on steel sheets was less than 6 g / (m²) at 90℃. 2 h).

12. A method for preparing the desulfurizing agent according to any one of claims 1-11, comprising the following steps: Step 1. Weigh each ingredient according to the formula. Step 2. Stir the strong oxidizing agent; Step 3. While maintaining stirring, add the stabilizer to the liquid from Step 2 to obtain a homogeneous liquid; Step 4. While maintaining stirring, add the corrosion inhibitor to the liquid from Step 3 to obtain a homogeneous liquid; Step 5. While maintaining stirring, add the reaction promoter to the liquid from Step 4 to obtain a homogeneous liquid; Step 6. While maintaining stirring, add the thickener to the liquid from Step 5 and stir until homogeneous to obtain the desulfurizing agent.

13. A method for desulfurizing acidic sulfur-containing wastewater, comprising the step of adding the desulfurizing agent according to any one of claims 1-11 to the acidic sulfur-containing wastewater to remove sulfides from the acidic sulfur-containing wastewater, referred to as the desulfurization step.

14. The desulfurization method of claim 13, wherein the desulfurization step is carried out at 40-80°C, and the amount of the desulfurizing agent is 2-10 parts by weight relative to 100 parts by weight of the acidic sulfur-containing wastewater.

15. The desulfurization method according to claim 13, wherein in the desulfurization step, the desulfurizing agent according to any one of claims 1-11 is directly injected into the oil and gas pipeline to remove sulfides from the acidic sulfur-containing wastewater.

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