A gaseous ferrous sulfide deodorizing passivator and a preparation method thereof

Abstract

This application belongs to the technical field of passivation and deodorization agents, specifically providing a gas-phase ferrous sulfide deodorizing and passivating agent and its preparation method. A gas-phase ferrous sulfide deodorizing and passivating agent includes component A and component B; component A includes the following components: a multifunctional block copolymer, a penetrant, a corrosion inhibitor, an antioxidant, isopropanol, and deionized water; component B includes the following components: triethanolamine, sodium perborate, and deionized water; the multifunctional block copolymer is prepared by reacting polyethylene glycol monomethyl ether, octadecyl acrylamide, and dopamine methyl acrylamide. The gas-phase ferrous sulfide deodorizing and passivating agent prepared by this application has good deodorizing, passivating, and cleaning effects.

Description

Technical Field

[0001] This application belongs to the technical field of passivation and deodorizing agents, and in particular relates to a gas-phase ferrous sulfide deodorizing and passivating agent and its preparation method. Background Technology

[0002] Long-term operation of oil refining units leads to synergistic reactions between internal metal components and substances such as H2S, mercaptans, CO2, HCl, and amine solutions, generating ferrous sulfide. This ferrous sulfide detaches from the metal surface and migrates within the unit with the material, accumulating in packing, reactors, tower bottoms, tower top demisters, heat exchangers, and tank bottoms. When the unit is opened for maintenance, the ferrous sulfide undergoes a violent oxidation reaction upon contact with air, releasing heat and exhibiting a high tendency to spontaneously combust, easily leading to fires and explosions. Currently, passivation cleaning of ferrous sulfide primarily employs liquid-phase cleaning. Liquid-phase cleaning uses methods such as circulation, immersion, and spraying to clean equipment and is widely used for cleaning equipment with significant ferrous sulfide scale. However, for complex equipment and internal components, liquid-phase cleaning struggles to achieve complete wetting and uniform contact, resulting in cleaning dead zones. Furthermore, the cleaning process requires large amounts of cleaning agents, is lengthy, and generates substantial amounts of wastewater, leading to high treatment costs.

[0003] To overcome the limitations of liquid-phase cleaning, current research has employed gas-phase cleaning methods. Gas-phase cleaning uses steam as a carrier, distributing the cleaning agent to various parts of the unit with the purging steam. It can clean areas inaccessible to liquid-phase cleaning, offering advantages such as shorter cleaning time and lower wastewater production. For example, patent application CN109234051A discloses a gas-phase cleaning agent for removing ferrous sulfide from oil refining units and its application method. This ferrous sulfide gas-phase cleaning agent comprises component A and component B. Component A consists of penetrant A, complexing agent, corrosion inhibitor, dispersant, free radical terminator, and water. Component B consists of penetrant B, passivating agent, corrosion inhibitor B, cleaning agent, and water. This method can efficiently and thoroughly remove ferrous sulfide and hydrogen sulfide from the system, exhibiting good oil stain removal performance.

[0004] The document states that a two-component vapor phase cleaning agent can effectively remove ferrous sulfide without corroding the equipment and saves cleaning water and time. However, during the cleaning operation, component B is injected first to remove oil and grime, and then component A is injected to remove ferrous sulfide and hydrogen sulfide. At the same time, it uses EDTA-2Na as a complexing agent, and the cleaning products are difficult to biodegrade and will hinder the cleaning effect when combined with surfactants. Summary of the Invention

[0005] To address the aforementioned issues and further improve the cleaning and passivation effect of ferrous sulfide deodorizing passivating agent, this application provides a ferrous sulfide deodorizing passivating agent and its preparation method.

[0006] This application first provides a gas-phase ferrous sulfide deodorizing and passivating agent, comprising component A and component B;

[0007] Component A comprises the following components by weight: 10-15 parts of multifunctional block copolymer, 5-8 parts of penetrant, 2-8 parts of corrosion inhibitor, 2-3 parts of antioxidant, 10-15 parts of isopropanol, and 51-71 parts of deionized water.

[0008] Component B comprises the following components by weight: 5-8 parts of triethanolamine, 2-3 parts of sodium perborate, and 89-93 parts of deionized water;

[0009] The multifunctional block copolymer is prepared by reacting polyethylene glycol monomethyl ether, octadecyl acrylamide, and dopamine methyl acrylamide.

[0010] Furthermore, the preparation method of the multifunctional block copolymer includes the following steps: A1, polyethylene glycol monomethyl ether, triethylamine and 2-bromoisobutyryl bromide are reacted to obtain mPEG-Br; A2, mPEG-Br, dopamine methylacrylamide and octadecylacrylamide are reacted with CuBr and ligand PMDETA by ATRP to obtain the multifunctional block copolymer.

[0011] Furthermore, in A2, the molar ratio of octadecylacrylamide to dopamine methacrylamide is 1:1.2-1.5.

[0012] Furthermore, the method for preparing octadecylacrylamide includes the following steps: reacting n-octadecylamine, triethylamine and acryloyl chloride to obtain octadecylacrylamide.

[0013] Furthermore, the preparation method of the dopamine methacrylamide includes the following steps: sodium tetraborate and sodium bicarbonate solution are purged with nitrogen gas, and then reacted with dopamine hydrochloride and methacrylic anhydride under weak alkalinity, room temperature, and nitrogen atmosphere to prepare dopamine methacrylamide.

[0014] Furthermore, the penetrant is dodecyl dimethyl betaine or dodecyl dimethylamine oxide.

[0015] Furthermore, the corrosion inhibitor is a water-soluble imidazoline or methylmorpholine.

[0016] Furthermore, the antioxidant is dialkyldiphenylamine or antioxidant 264.

[0017] Furthermore, this application provides a method for preparing a gas-phase ferrous sulfide deodorizing and passivating agent, characterized by comprising the following steps: S1, stirring and dissolving component A and component B respectively to obtain component A solution and component B solution; S2, mixing component A solution and component B solution according to a ratio to obtain the gas-phase ferrous sulfide deodorizing and passivating agent.

[0018] Furthermore, in S2, the ratio of component A to component B is 3-5:1.

[0019] Compared with the prior art, this application has the following beneficial effects:

[0020] The polyethylene glycol blocks in the multifunctional block copolymer molecules have excellent hydrophilicity, reducing the surface tension of the solution. Combined with a penetrant, this promotes the rapid spreading and penetration of the deodorizing and passivating agent on the surface of oil stains and ferrous sulfide scale. The catechol groups can chelate with iron ions on the surface of ferrous sulfide, thereby removing ferrous sulfide. Furthermore, the triethanolamine provides a weakly alkaline environment, improving the chelation efficiency of the catechol groups. Combined with the long-chain alkyl groups in the copolymer molecules, a dense hydrophobic passivation film can be formed on the surface of ferrous sulfide, effectively preventing the contact between the remaining ferrous sulfide and air and moisture, inhibiting the decomposition of ferrous sulfide to produce hydrogen sulfide gas. At the same time, triethanolamine can also quickly neutralize hydrogen sulfide, playing a deodorizing role. The combination of these components can effectively remove ferrous sulfide and hydrogen sulfide, achieving a passivation and deodorization effect without corroding the equipment. Detailed Implementation

[0021] To make the inventive objectives, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. Obviously, the described embodiments are only a portion of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only” is used, in which case another component may be added.

[0024] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0025] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0026] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0027] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0028] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0029] Example 1

[0030] The fumed and passivating agent in this embodiment comprises the following components by weight:

[0031] Component A: 10g of multifunctional block copolymer, 5g of dodecyl dimethyl betaine, 3g of water-soluble imidazoline, 2g of dialkyl diphenylamine, 10g of isopropanol, and 70g of deionized water;

[0032] Component B: 5g triethanolamine, 2g sodium perborate, 93g deionized water.

[0033] The preparation method of the fumed ferrous sulfide deodorizing and passivating agent in this embodiment is as follows:

[0034] S1. First, deionized water and isopropanol are added to a stirred tank. Under stirring at 300 rpm, multifunctional block copolymer, dodecyl dimethyl betaine, water-soluble imidazoline, and dialkyl diphenylamine are slowly added and stirred for 4 hours to obtain component A solution. Triethanolamine is dissolved in water and stirred evenly. Then, sodium perborate is slowly added at room temperature and stirred until completely dissolved to obtain component B solution.

[0035] S2, Mix component A solution and component B solution at a ratio of 3:1 and adjust the pH to 8.5 to obtain gas-phase ferrous sulfide deodorizing and passivating agent.

[0036] The preparation method of the multifunctional block copolymer in this embodiment is as follows:

[0037] In step A1, 10 g of polyethylene glycol monomethyl ether (Mn=2000), 50 mL of dichloromethane, and 2.21 mL of triethylamine were added sequentially to a 100 mL four-necked flask. The mixture was cooled to 0 °C, and 3.634 g of 2-bromoisobutyryl bromide dissolved in dichloromethane was slowly added under stirring. After the addition was done dropwise, the temperature was adjusted to room temperature, and the reaction was allowed to proceed for 48 h. The mixture was then filtered, and the filtrate was rotary evaporated. The filtrate was precipitated with a large amount of anhydrous diethyl ether. After several dissolution-precipitation cycles, the mixture was dried under vacuum to obtain mPEG-Br.

[0038] In a single-necked flask, 1.06 g (0.5 mmol) mPEG-Br, 7.8 mmol dopamine methacrylamide, 6.5 mmol octadecylacrylamide, 0.5 mmol PMDETA, 72 mg (0.5 mmol) CuBr, and 5 mL isopropanol were added sequentially. The mixture was then frozen, evacuated, and purged with nitrogen three times to remove oxygen from the system. The reaction was then carried out at room temperature under a nitrogen atmosphere for 8 hours. The reaction was then stopped, and the reaction solution was diluted with THF. The solution was passed through a short neutral alumina column to remove copper salts from the system. The solvent was removed by rotary evaporation, and the solution was precipitated with cold n-hexane. The dissolution-precipitation process was repeated three times, and the product was dried under vacuum to obtain a multifunctional block copolymer.

[0039] The preparation method of octadecylacrylamide in this embodiment is as follows:

[0040] 8.33 g of n-octadecylamine and 4.5 mL of triethylamine were dissolved in 250 mL of tetrahydrofuran, and 3 mL of acryloyl chloride was dissolved in 30 mL of tetrahydrofuran. The solutions were slowly added dropwise to the above solution over 30 min in an ice bath. After the addition was complete, the reaction mixture was stirred overnight at room temperature. After the reaction was completed, the crude product was obtained by filtration, dried in methanol and recrystallized to obtain octadecylacrylamide.

[0041] The preparation method of dopamine methacrylamide in this embodiment is as follows:

[0042] 12.58 g of sodium tetraborate and 5.94 g of sodium bicarbonate were dissolved in 100 mL of distilled water. The solution was bubbled under nitrogen for 30 min, and then 7.8 g of dopamine hydrochloride was added. A mixed solution was prepared by adding 6 mL of methacrylic anhydride to 30 mL of degassed tetrahydrofuran and then adding this solution dropwise to the mixture. NaOH solution was added dropwise to adjust the pH to 8.5. The reaction mixture was stirred for 24 h at room temperature under a nitrogen atmosphere. The solution was then washed twice with 30 mL of ethyl acetate, and the resulting aqueous layer was filtered under vacuum. The solution was acidified to pH 2 with 6 M hydrochloric acid solution. The mixture was extracted three times with 50 mL of ethyl acetate, and the organic layer was dried over MgSO4. The solution was concentrated under vacuum to approximately 15 mL and precipitated in 220 mL of n-hexane at 0 °C. The precipitate was then dried overnight in a vacuum oven to prepare dopamine methacrylamide.

[0043] Example 2

[0044] The fumed and passivating agent in this embodiment comprises the following components by weight:

[0045] Component A: 12g of multifunctional block copolymer, 7g of dodecyl dimethyl betaine, 6g of water-soluble imidazoline, 3g of dialkyl diphenylamine, 13g of isopropanol, and 59g of deionized water;

[0046] Component B: Triethanolamine 7g, Sodium perborate 2.5g, Deionized water 90g;

[0047] The preparation method of the fumed ferrous sulfide deodorizing and passivating agent in this embodiment is as follows:

[0048] S1. First, deionized water and isopropanol are added to a stirred tank. Under stirring at 300 rpm, multifunctional block copolymer, dodecyl dimethyl betaine, water-soluble imidazoline, and dialkyl diphenylamine are slowly added and stirred for 4 hours to obtain component A solution. Triethanolamine is dissolved in water and stirred evenly. Then, sodium perborate is slowly added at room temperature and stirred until completely dissolved to obtain component B solution.

[0049] S2, Mix component A solution and component B solution at a ratio of 4:1 and adjust the pH to 8.5 to obtain a gas-phase ferrous sulfide deodorizing and passivating agent.

[0050] The preparation method of the multifunctional block copolymer in this embodiment is as follows:

[0051] In step A1, 10 g of polyethylene glycol monomethyl ether (Mn=2000), 50 mL of dichloromethane, and 2.21 mL of triethylamine were added sequentially to a 100 mL four-necked flask. The mixture was cooled to 0 °C, and 3.634 g of 2-bromoisobutyryl bromide dissolved in dichloromethane was slowly added under stirring. After the addition was done dropwise, the temperature was adjusted to room temperature, and the reaction was allowed to proceed for 48 h. The mixture was then filtered, and the filtrate was rotary evaporated. The filtrate was precipitated with a large amount of anhydrous diethyl ether. After several dissolution-precipitation cycles, the mixture was dried under vacuum to obtain mPEG-Br.

[0052] In a single-necked flask, 1.06 g (0.5 mmol) mPEG-Br, 8.75 mmol dopamine methacrylamide, 6.25 mmol octadecylacrylamide, 0.5 mmol PMDETA, 72 mg (0.5 mmol) CuBr, and 5 mL isopropanol were added sequentially. The mixture was then frozen, evacuated, and purged with nitrogen three times to remove oxygen from the system. The reaction was then carried out at room temperature under a nitrogen atmosphere for 8 hours. The reaction was then stopped, and the reaction solution was diluted with THF. The solution was passed through a short neutral alumina column to remove copper salts from the system. The solvent was removed by rotary evaporation, and the solution was precipitated with cold n-hexane. The dissolution-precipitation process was repeated three times, and the solution was dried under vacuum to obtain the multifunctional block copolymer.

[0053] The preparation method of octadecylacrylamide in this embodiment is as follows:

[0054] 8.33 g of n-octadecylamine and 4.5 mL of triethylamine were dissolved in 250 mL of tetrahydrofuran, and 3 mL of acryloyl chloride was dissolved in 30 mL of tetrahydrofuran. The solutions were slowly added dropwise to the above solution over 30 min in an ice bath. After the addition was complete, the reaction mixture was stirred overnight at room temperature. After the reaction was completed, the crude product was obtained by filtration, dried in methanol and recrystallized to obtain octadecylacrylamide.

[0055] The preparation method of dopamine methacrylamide in this embodiment is as follows:

[0056] 12.58 g of sodium tetraborate and 5.94 g of sodium bicarbonate were dissolved in 100 mL of distilled water. The solution was bubbled under nitrogen for 30 min, and then 7.8 g of dopamine hydrochloride was added. A mixed solution was prepared by adding 6 mL of methacrylic anhydride to 30 mL of degassed tetrahydrofuran and then adding this solution dropwise to the mixture. NaOH solution was added dropwise to adjust the pH to 8.5. The reaction mixture was stirred for 24 h at room temperature under a nitrogen atmosphere. The solution was then washed twice with 30 mL of ethyl acetate, and the resulting aqueous layer was filtered under vacuum. The obtained solution was acidified to pH 2 with 6 M hydrochloric acid solution. The mixture was extracted three times with 50 mL of ethyl acetate, and the organic layer was dried with MgSO4. The solution was concentrated under vacuum to approximately 15 mL and precipitated in 220 mL of n-hexane at 0 °C. The precipitate was dried overnight in a vacuum oven to prepare dopamine methacrylamide.

[0057] Example 3

[0058] The fumed and passivating agent in this embodiment comprises the following components by weight:

[0059] Component A: 15g multifunctional block copolymer, 8g dodecyl dimethylamine oxide, 8g methylmorpholine, 2643g antioxidant, 15g isopropanol, 51g deionized water;

[0060] Component B: Triethanolamine 8g, Sodium perborate 3g, Deionized water 89g;

[0061] The preparation method of the fumed ferrous sulfide deodorizing and passivating agent in this embodiment is as follows:

[0062] S1. First, deionized water and isopropanol are added to a stirred tank. Under stirring at 300 rpm, multifunctional block copolymer, dodecyl dimethylamine oxide, methylmorpholine, and antioxidant 264 are slowly added and stirred for 4 hours to obtain component A solution. Triethanolamine is dissolved in water and stirred evenly. Sodium perborate is slowly added at room temperature and stirred until completely dissolved to obtain component B solution.

[0063] S2, Mix component A solution and component B solution at a ratio of 5:1 and adjust the pH to 8.5 to obtain a gas-phase ferrous sulfide deodorizing and passivating agent.

[0064] The preparation method of the multifunctional block copolymer in this embodiment is as follows:

[0065] In step A1, 10 g of polyethylene glycol monomethyl ether (Mn=2000), 50 mL of dichloromethane, and 2.21 mL of triethylamine were added sequentially to a 100 mL four-necked flask. The mixture was cooled to 0 °C, and 3.634 g of 2-bromoisobutyryl bromide dissolved in dichloromethane was slowly added under stirring. After the addition was done dropwise, the temperature was adjusted to room temperature, and the reaction was allowed to proceed for 48 h. The mixture was then filtered, and the filtrate was rotary evaporated. The filtrate was precipitated with a large amount of anhydrous diethyl ether. After several dissolution-precipitation cycles, the mixture was dried under vacuum to obtain mPEG-Br.

[0066] In a single-necked flask, 1.06 g (0.5 mmol) mPEG-Br, 9 mmol dopamine methacrylamide, 6 mmol octadecylacrylamide, 0.5 mmol PMDETA, 72 mg (0.5 mmol) CuBr, and 5 mL isopropanol were added sequentially. The mixture was then frozen, evacuated, and purged with nitrogen three times to remove oxygen from the system. The reaction was then carried out at room temperature under a nitrogen atmosphere for 8 hours. The reaction was then stopped, and the reaction solution was diluted with THF. The solution was passed through a short neutral alumina column to remove copper salts from the system. The solvent was removed by rotary evaporation, and the solution was precipitated with cold n-hexane. The dissolution-precipitation process was repeated three times, and the product was dried under vacuum to obtain the multifunctional block copolymer.

[0067] The preparation method of octadecylacrylamide in this embodiment is as follows:

[0068] 8.33 g of n-octadecylamine and 4.5 mL of triethylamine were dissolved in 250 mL of tetrahydrofuran, and 3 mL of acryloyl chloride was dissolved in 30 mL of tetrahydrofuran. The solutions were slowly added dropwise to the above solution over 30 min in an ice bath. After the addition was complete, the reaction mixture was stirred overnight at room temperature. After the reaction was completed, the crude product was obtained by filtration, dried in methanol and recrystallized to obtain octadecylacrylamide.

[0069] The preparation method of dopamine methacrylamide in this embodiment is as follows:

[0070] 12.58 g of sodium tetraborate and 5.94 g of sodium bicarbonate were dissolved in 100 mL of distilled water. The solution was bubbled under nitrogen for 30 min, and then 7.8 g of dopamine hydrochloride was added. A mixed solution was prepared by adding 6 mL of methacrylic anhydride to 30 mL of degassed tetrahydrofuran and then adding this solution dropwise to the mixture. NaOH solution was added dropwise to adjust the pH to 8.5. The reaction mixture was stirred for 24 h at room temperature under a nitrogen atmosphere. The solution was then washed twice with 30 mL of ethyl acetate, and the resulting aqueous layer was filtered under vacuum. The obtained solution was acidified to pH 2 with 6 M hydrochloric acid solution. The mixture was extracted three times with 50 mL of ethyl acetate, and the organic layer was dried with MgSO4. The solution was concentrated under vacuum to approximately 15 mL and precipitated in 220 mL of n-hexane at 0 °C. The precipitate was dried overnight in a vacuum oven to prepare dopamine methacrylamide.

[0071] Comparative Example 1

[0072] The fumed and passivating agent in this comparative example comprises the following components by weight:

[0073] Component A: 12g of multifunctional block copolymer, 7g of dodecyl dimethyl betaine, 6g of water-soluble imidazoline, 3g of dialkyl diphenylamine, 13g of isopropanol, and 59g of deionized water;

[0074] Component B: Triethanolamine 7g, Sodium perborate 2.5g, Deionized water 90g;

[0075] The preparation method of the gas-phase ferrous sulfide deodorizing and passivating agent in this comparative example is the same as that in Example 2.

[0076] The preparation method of the multifunctional block copolymer in this comparative example is as follows:

[0077] In step A1, 10 g of polyethylene glycol monomethyl ether (Mn=2000), 50 mL of dichloromethane, and 2.21 mL of triethylamine were added sequentially to a 100 mL four-necked flask. The mixture was cooled to 0 °C, and 3.634 g of 2-bromoisobutyryl bromide dissolved in dichloromethane was slowly added under stirring. After the addition was done dropwise, the temperature was adjusted to room temperature, and the reaction was allowed to proceed for 48 h. The mixture was then filtered, and the filtrate was rotary evaporated. The filtrate was precipitated with a large amount of anhydrous diethyl ether. After several dissolution-precipitation cycles, the mixture was dried under vacuum to obtain mPEG-Br.

[0078] In a single-necked flask, 1.06 g (0.5 mmol) mPEG-Br, 15 mmol octadecylacrylamide, 0.5 mmol PMDETA, 72 mg (0.5 mmol) CuBr, and 5 mL isopropanol were added sequentially. The mixture was then frozen, evacuated, and purged with nitrogen three times to remove oxygen from the system. The reaction was then carried out at room temperature under a nitrogen atmosphere for 8 hours. The reaction was then stopped, and the reaction solution was diluted with THF. The solution was passed through a short neutral alumina column to remove copper salts from the system. The solvent was removed by rotary evaporation, and the solution was precipitated with cold n-hexane. The dissolution-precipitation process was repeated three times, and the product was dried under vacuum to obtain a multifunctional block copolymer.

[0079] The preparation method of octadecylacrylamide in this comparative example is the same as that in Example 2.

[0080] Comparative Example 2

[0081] The fumed and passivating agent in this comparative example comprises the following components by weight:

[0082] Component A: 12g of multifunctional block copolymer, 7g of dodecyl dimethyl betaine, 3g of dialkyl diphenylamine, 13g of isopropanol, and 65g of deionized water;

[0083] Component B: Sodium perborate 2.5g, deionized water 97g;

[0084] The preparation method of the gas-phase ferrous sulfide deodorizing and passivating agent in this comparative example is as follows:

[0085] S1. First, deionized water and isopropanol are added to a stirred tank. Then, multifunctional block copolymer, dodecyl dimethyl betaine, water-soluble imidazoline, and dialkyl diphenylamine are slowly added while stirring at 300 rpm. The mixture is stirred for 4 hours to obtain component A solution. Sodium perborate is dissolved in water and stirred until completely dissolved to obtain component B solution.

[0086] S2, Mix component A solution and component B solution at a ratio of 4:1 and adjust the pH to 8.5 to obtain a gas-phase ferrous sulfide deodorizing and passivating agent.

[0087] The preparation method of the multifunctional block copolymer in this comparative example is as follows:

[0088] In step A1, 10 g of polyethylene glycol monomethyl ether (Mn=2000), 50 mL of dichloromethane, and 2.21 mL of triethylamine were added sequentially to a 100 mL four-necked flask. The mixture was cooled to 0 °C, and 3.634 g of 2-bromoisobutyryl bromide dissolved in dichloromethane was slowly added under stirring. After the addition was done dropwise, the temperature was adjusted to room temperature, and the reaction was allowed to proceed for 48 h. The mixture was then filtered, and the filtrate was rotary evaporated. The filtrate was precipitated with a large amount of anhydrous diethyl ether. After several dissolution-precipitation cycles, the mixture was dried under vacuum to obtain mPEG-Br.

[0089] In a single-necked flask, 1.06 g (0.5 mmol) mPEG-Br, 15 mmol dopamine methacrylamide, 0.5 mmol PMDETA, 72 mg (0.5 mmol) CuBr, and 5 mL isopropanol were added sequentially. The mixture was then frozen, evacuated, and purged with nitrogen three times to remove oxygen from the system. The reaction was then carried out at room temperature under a nitrogen atmosphere for 8 hours. The reaction was then stopped, and the reaction solution was diluted with THF. The solution was passed through a short neutral alumina column to remove copper salts from the system. The solvent was removed by rotary evaporation, and the solution was precipitated with cold n-hexane. The dissolution-precipitation process was repeated three times, and the product was dried under vacuum to obtain a multifunctional block copolymer.

[0090] The preparation method of dopamine methacrylamide in this comparative example is the same as that in Example 2.

[0091] Performance testing

[0092] The gaseous ferrous sulfide deodorizing and passivating agent was blown into the equipment by steam. After cleaning, the cleaning rate and corrosion rate of the gaseous ferrous sulfide deodorizing and passivating agent were tested according to GB / T25146-2010. The hydrogen sulfide content in the closed equipment was detected at 5-hour intervals.

[0093] Table 1. Performance test results of the gas-phase ferrous sulfide deodorizing and passivating agents in Examples 1-3 and Comparative Examples 1-2.

[0094]

[0095] Analysis of Examples 1-3 and Comparative Examples 1-2, combined with Table 1, shows that the multifunctional block copolymer molecules, through copolymerization of the hydrophilic segment polyethylene glycol, the hydrophobic segment octadecylacrylamide, and dopamine methacrylamide, and compounded with functional additives such as penetrants and triethanolamine, enable the gas-phase deodorizing and passivating agent to effectively remove ferrous sulfide and neutralize hydrogen sulfide, thereby achieving the deodorizing and passivating effect.

[0096] Analysis of Table 1 shows that, compared to Examples 1-3, the gas-phase ferrous sulfide deodorizing and passivating agent prepared in Comparative Example 1, with its multifunctional block copolymer without polymerized dopamine methacrylamide, is less effective at targeting and chelating iron ions on the surface of ferrous sulfide, resulting in a decrease in its ability to remove ferrous sulfide. Consequently, the cleaning rate of the gas-phase ferrous sulfide deodorizing and passivating agent in Comparative Example 1 is significantly reduced. Similarly, the gas-phase ferrous sulfide deodorizing and passivating agent prepared in Comparative Example 2, with its multifunctional block copolymer without polymerized octadecylacrylamide and without added triethanolamine, is less likely to form a passivation film and cannot inhibit the decomposition of residual ferrous sulfide to produce hydrogen sulfide. Consequently, the corrosion rate and hydrogen sulfide content of the gas-phase ferrous sulfide deodorizing and passivating agent in Comparative Example 2 increase.

[0097] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A fumed ferrous sulfide deodorizing and passivating agent, characterized in that, Includes component A and component B; Component A comprises the following components by weight: 10-15 parts of multifunctional block copolymer, 5-8 parts of penetrant, 2-8 parts of corrosion inhibitor, 2-3 parts of antioxidant, 10-15 parts of isopropanol, and 51-71 parts of deionized water. Component B comprises the following components by weight: 5-8 parts of triethanolamine, 2-3 parts of sodium perborate, and 89-93 parts of deionized water; The multifunctional block copolymer is prepared by reacting polyethylene glycol monomethyl ether, octadecyl acrylamide, and dopamine methyl acrylamide. The preparation method of the multifunctional block copolymer includes the following steps: A1, polyethylene glycol monomethyl ether, triethylamine and 2-bromoisobutyryl bromide are reacted to obtain mPEG-Br; A2, mPEG-Br, dopamine methacrylamide and octadecylacrylamide are reacted with CuBr and ligand PMDETA by ATRP to obtain the multifunctional block copolymer. In A2, the molar ratio of octadecylacrylamide to dopamine methacrylamide is 1:1.2-1.5; The penetrant is dodecyl dimethyl betaine or dodecyl dimethyl amine oxide; The corrosion inhibitor is a water-soluble imidazoline or methylmorpholine; The antioxidant is dialkyldiphenylamine or antioxidant 264.

2. The fumed deodorizing and passivating agent of ferrous sulfide according to claim 1, characterized in that, The method for preparing octadecylacrylamide includes the following steps: reacting n-octadecylamine, triethylamine and acryloyl chloride to obtain octadecylacrylamide.

3. The fumed deodorizing and passivating agent of ferrous sulfide according to claim 1, characterized in that, The preparation method of the dopamine methacrylamide includes the following steps: sodium tetraborate and sodium bicarbonate solution are purged with nitrogen gas, and then reacted with dopamine hydrochloride and methacrylic anhydride under weak alkalinity, room temperature and nitrogen atmosphere to prepare dopamine methacrylamide.

4. A method for preparing a gas-phase ferrous sulfide deodorizing and passivating agent as described in any one of claims 1-3, characterized in that, The process includes the following steps: S1, dissolving component A and component B separately by stirring to obtain component A solution and component B solution; S2, mixing component A solution and component B solution according to the specified ratio to obtain gas-phase ferrous sulfide deodorizing and passivating agent.

5. The preparation method of a gas-phase ferrous sulfide deodorizing and passivating agent according to claim 4, characterized in that, In S2, the ratio of component A to component B is 3-5:1.

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