Preparation, application, regeneration and recovery method of Ni-doped defective WS2 catalyst

Abstract

The application belongs to the technical field of environmental protection and resource recycling, and discloses a preparation, application, regeneration and recycling method of a Ni-doped defect WS2 catalyst. Molecular sieves, nickel salt, tungstate, sulfidation agent, inorganic hydroxylamine hydrochloride and organic modifier are dissolved in deionized water, organic acid is added, and hydrothermal reaction is carried out for a certain time; after the reaction is completed, natural cooling is carried out to room temperature, suction filtration, washing and drying are carried out, and a solid product is obtained; the solid product is placed in a photo-thermal catalytic reaction instrument for H2 reduction, and the Ni-doped defect WS2 catalyst is obtained. The metal components of the prepared catalyst are suitable for the action of the carrier, have high hydrogenation desulfurization activity and stability, and the valuable metals in the waste hydrogenation desulfurization catalyst can be recycled by hydrogenation reduction regeneration.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection and resource recycling, and more particularly to a method for preparing a Ni-doped defective WS2 catalyst and using it for hydrodesulfurization, as well as a method for recycling and recovering the catalyst. Background Art

[0002] Blast furnace gas is a by-product produced during the ironmaking process, and its main components include CO, CO2, H2, CH4, N2 and sulfur-containing pollutants. The combustible gases such as CO and H2 in blast furnace gas have high recovery value. In order to recycle the combustible gases in blast furnace gas, it is necessary to carry out dust removal, desulfurization and other purification processes on the blast furnace gas. Hydrogenation desulfurization (HDS) technology is a kind of organic sulfur removal method that is currently more widely used. It can meet the requirements of blast furnace gas desulfurization accuracy. The method has high conversion efficiency for organic sulfur, few by-products, a wide temperature range, and can directly utilize hydrogen in the gas for desulfurization, which can achieve deep purification of blast furnace gas. CN103627425A discloses a method for oil residue hydrodesulfurization, which immerses nickel salt or cobalt salt talc into sodium salt solution, obtains a catalyst with high dispersion of supported metal after heat treatment, and has high desulfurization activity. However, a large amount of sodium element is introduced into the catalyst, which destroys the surface properties of the catalyst and affects the stability of the catalyst. Currently, hydrodesulfurization catalysts have problems such as high reaction temperature and poor stability, which hinder their large-scale industrial application. Therefore, the preparation of highly active and stable catalysts is of great significance for the precise removal of organic sulfur in coal gas.

[0003] my country has abundant tungsten resources and high production. Tungsten materials are widely used in aerospace, military, advanced manufacturing, and other fields due to their excellent properties, such as high melting point, high strength, and good thermal conductivity. Tungsten sulfide is a two-dimensional transition metal dichalcogenide (2D TMD) with a unique layered structure. It exhibits excellent cracking properties, high catalytic activity, reliable stability, and a long service life. It has great application potential in research fields such as optics, electronics, tribology, hydrogen evolution, sodium storage, photocatalysis, and thermal catalysis. It is often used as a petroleum catalyst, hydrodesulfurization catalyst, fuel manufacturing, anode for organic electrolyte rechargeable batteries, and in the production of nano-ceramic composites. Methods for preparing tungsten disulfide include mechanical exfoliation, electrochemical lithium ion intercalation, liquid phase exfoliation, chemical vapor precipitation, and hydrothermal methods. The hydrothermal method offers mild reaction conditions and strong operability. By varying the hydrothermal reaction conditions (such as hydrothermal temperature, hydrothermal duration, and ratio), the size and morphology of WS2 can be effectively controlled. CN111036276A discloses a tungsten-based, presulfurization-free hydrotalcite-type hydrodesulfurization catalyst and its preparation method. By introducing thiotungstate anions into the interlayers of nickel-aluminum hydrotalcite and then activating it with nitrogen at high temperature, the resulting tungsten-based, presulfurization-free hydrotalcite-type hydrodesulfurization catalyst achieves high dispersion and high loading of active metal components. The catalyst exhibits high hydrodesulfurization activity in the hydrodesulfurization reaction of oil products.

[0004] Catalysts are crucial to the development of modern industry. In chemical industry production, 60% to 80% of chemical reactions require corresponding catalysts. In the fields of environmental protection, refined desulfurization, and crude oil refining, a large amount of spent hydrodesulfurization catalyst is generated. Because it contains crude oil and heavy metals, which are harmful to the environment, it has been classified as hazardous waste by my country's Ministry of Environmental Protection. The valuable metals in spent hydrodesulfurization catalysts serve as high-quality secondary resources. Recycling them not only alleviates resource shortages but also protects the environment. CN116732319A discloses a method for resource utilization of spent hydrodesulfurization catalysts. The spent hydrodesulfurization catalysts (comprising aluminum oxide, molybdenum oxide, cobalt oxide, and phosphorus oxide) are obtained from a gasoline cracking unit. High-purity Mo and Co products are obtained by impregnation with alkaline solution, solid-liquid separation, and the addition of Mo and Co precipitants. The remaining slag can be used to prepare aluminum oxide, achieving high-value-added utilization of all elements. Therefore, recycling spent hydrodesulfurization catalysts not only prevents the loss and waste of valuable metals (W and Ni), but also alleviates resource shortages and reduces environmental pollution, resulting in significant environmental and economic benefits.

[0005] Therefore, how to develop a coal gas deep hydrodesulfurization catalyst and provide a resource utilization idea for waste hydrodesulfurization catalyst are problems that need to be solved urgently by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a method for the preparation, application, regeneration and recovery of a Ni-doped defective WS2 catalyst. A one-step hydrothermal method is used to prepare a Ni-doped defective WS2 nanosheet catalyst. The metal components of the prepared catalyst react appropriately with the carrier, have high hydrodesulfurization activity and stability, and regenerate the catalyst with decreased desulfurization efficiency through hydrogenation reduction, thereby recycling the valuable metals in the waste hydrodesulfurization catalyst.

[0007] One of the purposes of the present invention is to provide a method for preparing a Ni-doped defective WS2 catalyst, comprising the following steps:

[0008] S11. The molecular sieve, nickel salt, tungstate, sulfiding agent, inorganic hydroxylamine hydrochloride and organic modifier are dissolved in deionized water, a certain amount of organic acid is added, and the mixture is transferred to a polytetrafluoroethylene reactor and subjected to hydrothermal reaction for a certain period of time;

[0009] S12. After the reaction is completed, the reaction is cooled to room temperature, filtered, washed with deionized water and anhydrous ethanol several times, and dried in an oven at 80 to 120 ° C for 8 to 16 hours to obtain a solid product;

[0010] S13. The solid product is passed through a 40-60 mesh sieve, placed in a photothermal catalytic reactor, and reduced with 2%-10% H2 at 300°C-350°C to obtain a Ni-doped defective WS2 catalyst.

[0011] Preferably, in S11, the molecular sieve is selected from ZSM-5, SBA-15, KIT-6, and MCM-41, the nickel salt is selected from nickel nitrate, nickel sulfate, and nickel hydroxide, the tungstate is selected from ammonium metatungstate and sodium tungstate, the vulcanizing agent is selected from thiourea and thioacetamide, the inorganic hydroxylamine hydrochloride is selected from hydroxylamine hydrochloride and N,O-dimethylhydroxylamine hydrochloride, the organic modifier is selected from hexadecyltrimethylammonium bromide and ascorbic acid, and the organic acid is selected from formic acid, acetic acid, sulfuric acid, and phosphoric acid.

[0012] Preferably, the mass ratio of molecular sieve, nickel salt, tungstate, sulfiding agent, inorganic hydroxylamine hydrochloride, and organic modifier is (0.1-1):(1-2):(1-2):(1-2):(1-2):(1-2);

[0013] The solid-liquid ratio of the molecular sieve to deionized water is 1 / 200 to 1 / 50, and the solid-liquid ratio of the molecular sieve to the organic acid is 0.0082 to 0.0273.

[0014] Preferably, in S11, the temperature of the hydrothermal reaction is 160° C. to 240° C., and the time is 7 h to 24 h.

[0015] The inventive concept of adopting the above technical solution is:

[0016] 1. Nickel salt and sulfiding agent will generate Ni3S2 in a reactor at 220℃ under high temperature and high pressure environment, providing sulfur vacancies for hydrogenation and removal of organic sulfur.

[0017] 2. Tungstate and sulfiding agent generate WS2 in a reactor at 220℃ under high temperature and high pressure environment, providing more active sites for hydrogenation desulfurization.

[0018] 3. The hydrothermal method introduces organic species (including organic hydroxy acids or hydroxy salts and organic sulfiding agents). During the reaction, the organic species will be adsorbed on the surface of the sulfide ions in large quantities, partially restricting the growth of sulfide crystals, forming a defect-rich structure, and providing more defect sites, thereby improving the activity of the catalyst.

[0019] The second object of the present invention is to provide an application of a Ni-doped defective WS2 catalyst, comprising the following steps:

[0020] In the photothermal catalytic reactor, a certain amount of Ni-doped defective WS2 catalyst was introduced at a flow rate of 200 mL / min and a reaction space velocity of 30,000 to 40,000 h. -1 , blast furnace gas with ultraviolet light intensity of 7 to 10W, and the use of catalysts to carry out photothermal synergistic hydrogenation conversion of organic sulfur at 120℃ to 200℃, converting the difficult-to-remove organic sulfur into easily removable inorganic sulfur (H2S), and then the H2S is adsorbed and purified through an adsorption column filled with a fine desulfurization catalyst to complete the fine removal of H2S.

[0021] The beneficial effects of adopting the above technical solution are: the hydrogenation conversion rate of organic sulfur in coal gas by the Ni-doped defective WS2 catalyst reaches 98% to 100%, and the catalyst stability is greater than 60h.

[0022] Preferably, the fine desulfurization catalyst is selected from various combinations of zinc salts, iron oxide, molecular sieves, activated carbon and bismuth vanadium.

[0023] Preferably, the Ni-doped defective WS2 catalyst is 0.2 g.

[0024] Furthermore, the present invention provides a method for preparing a fine desulfurization catalyst, the specific steps of which are as follows:

[0025] (1) dissolving a zinc salt in a mixed solution of an organic alcohol having a volume ratio of 20% to 60% to obtain a zinc-containing solution;

[0026] Molecular sieve sol is prepared by mixing molecular sieve and anhydrous ethanol in a molar ratio of 1:1 to 1:4. During the mixing and stirring, distilled water and inorganic acid are added dropwise to ensure that the molar ratio of molecular sieve: distilled water: inorganic acid is 1:1:0.1 to 1:2:0.5;

[0027] A zinc-containing solution and a molecular sieve sol are mixed to obtain a precursor solution, wherein the molar ratio of zinc to molecular sieve is 1:1 to 1:2.

[0028] (2) The precursor solution is placed in an oven at 80°C to 120°C and dried for 12 to 24 hours to obtain a precursor.

[0029] (3) After drying and grinding the precursor, place it in a muffle furnace at 200℃~400℃ and calcine it for 2~6h.

[0030] (4) The tablets were passed through a 40-60 mesh sieve and 0.2-0.5 g was filled into a glass reaction tube with an inner diameter of 8 mm to obtain a refined desulfurization catalyst.

[0031] Furthermore, the working conditions of the fine desulfurization catalyst are: H2 content of 4% to 10%, gas velocity of 15 to 30 mL / min, and adsorption temperature of 20°C to 100°C.

[0032] Preferably, the zinc salt is selected from zinc oxide, zinc nitrate, zinc sulfate, and zinc carbonate;

[0033] The organic alcohol mixture is selected from two of methanol, ethylene glycol, and propylene glycol, and the mixing volume ratio is 1:1 to 1:2;

[0034] The solid-to-liquid ratio of the zinc salt and organic alcohol mixture is 0.02 to 0.1;

[0035] Molecular screening was performed from ZSM-5, SBA-15, KIT-6, and MCM-41;

[0036] The inorganic acid is selected from hydrochloric acid, sulfuric acid, and phosphoric acid.

[0037] The third object of the present invention is to provide a recycling method for Ni-doped defective WS2 catalyst, which comprises the following steps:

[0038] The Ni-doped defective WS2 catalyst with reduced desulfurization efficiency is regenerated under a high-temperature and high-pressure hydrogen atmosphere, and the number of regeneration cycles is ≥2.

[0039] Preferably, the regeneration conditions are: at 320°C to 470°C, 1.6 to 9.8 MPa and a flow rate of 20 to 80 mL / min, 2% to 5% hydrogen is introduced, N2 is used as the protective gas, and regeneration is completed after 12 to 36 hours.

[0040] The beneficial effect of adopting the above technical solution is that the regeneration efficiency of the catalyst with reduced desulfurization efficiency is greater than 98%, and generally 2 to 5 hydrogen reduction regenerations are the most economical.

[0041] A fourth object of the present invention is to provide a method for resource utilization of spent hydrodesulfurization catalysts, the specific steps of which are as follows:

[0042] S21. The spent hydrodesulfurization catalyst is calcined in an air atmosphere at 500 ℃ to 800 ℃ for 3h to 6h;

[0043] S22. A 0.1 mol / L to 3.0 mol / L aqueous solution of an inorganic acid is mixed with the spent hydrodesulfurization catalyst at a solid-liquid ratio of 15:1 to 10:1 and ultrasonically impregnated at 50°C to 100°C for 30 to 60 minutes. The residue and the filtrate are separated by filtration, and the leaching rate of valuable metals is greater than 98%;

[0044] S23. A quaternary ammonium salt aqueous solution having a concentration of 0.5 mol / L to 2.0 mol / L is added to the filtrate, kerosene is added in an amount of 60% to 65% by volume of the total reaction solution as a diluent, and n-decanol is added in an amount of 5% to 7.5% by volume of the total reaction solution as a modifier, with the ratio of the aqueous phase to the organic phase being 1:1 to 1:2, to obtain a tungsten-containing extract (oil phase) and a nickel-containing extract (oil phase), with extraction rates of tungsten and nickel both exceeding 98%.

[0045] S24. Adding an aqueous solution of NH4OH or NaOH to the tungsten-containing extract and stirring on an electromagnetic stirrer at 80°C to 100°C until dry to obtain an ammonium tungstate or sodium tungstate compound having a purity greater than 99%;

[0046] H2C2O4 or H2SO4 or HCl is added to the nickel-containing extract as a precipitant, and precipitation recovery is carried out in an environment of 40°C to 60°C to obtain nickel oxalate, nickel sulfate or nickel chloride with a purity greater than 98%.

[0047] Preferably, the inorganic acid is selected from sulfuric acid, hydrochloric acid, and nitric acid; the quaternary ammonium salt is selected from ammonium hydroxide or methyltrioctylammonium chloride; and the kerosene is analytically pure, selected from No. 200 solvent oil with a purity of 99.99% or No. 260 solvent oil with a purity of 99%.

[0048] Preferably, in step S24, the concentration of the NH4OH or NaOH aqueous solution is 0.1 mol / L to 1.0 mol / L, and the molar ratio of hydroxide to tungstate ion is 1:1 to 1:3;

[0049] The concentration of H2C2O4 or H2SO4 or HCl solution is 0.1 mol / L to 1.0 mol / L, the molar ratio of oxalate to nickel ion is 1:1 to 1:2, the molar ratio of sulfate to nickel ion is 1:1 to 1:3, and the molar ratio of chloride ion to nickel ion is 3:1 to 2:1.

[0050] The fifth object of the present invention is to provide a Ni-doped defective WS2 catalyst, which is doped on a spherical catalyst stacked with multiple layers of flaky WS2 through a one-step hydrothermal method using Ni as an active component and is used in the coal gas hydrodesulfurization process.

[0051] Compared with existing technologies, the catalyst developed in this invention converts organic sulfur gases such as COS, CS2, and CH3SH into H2S through a synergistic photothermal conversion at 200°C. The organic sulfur conversion rate is close to 100%, and the H2S selectivity is greater than 99%. Catalysts with reduced desulfurization efficiency can be regenerated with hydrogen reduction to a regeneration efficiency greater than 98%, allowing for 3-5 recycling cycles. The catalyst that becomes ineffective after recycling is considered a spent hydrodesulfurization catalyst. Finally, the valuable metals (W and Ni) in the spent hydrodesulfurization catalyst are recovered using a comprehensive process of pretreatment, leaching, extraction, stripping, and productization.

[0052] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

[0053] 1. The present invention discloses a method for preparing a Ni-doped defective WS2 catalyst and using it for hydrodesulfurization. Through the synergistic conversion of organic sulfur in coal gas by light and heat, the corrosion of corrosive chemicals on back-end equipment and transportation pipelines can be reduced, thereby extending the service life and operating efficiency of the equipment.

[0054] 2. The present invention adopts a hydrothermal method to introduce organic species (including organic hydroxy acids or hydroxy salts and organic sulfiding agents). During the reaction process, the organic species will be adsorbed on the surface of the sulfide ions in large quantities, partially restricting the growth of sulfide crystals, forming a defect-rich structure, and providing more defect sites, thereby improving the activity of the catalyst.

[0055] 3. The catalyst preparation method utilizes organic hydroxy acids or hydroxy salts as additives, which can form complexes with metal ions, resulting in the simultaneous sulfurization of nickel and tungsten, thus ensuring uniform distribution of the catalyst on the support. The presence of nickel significantly enhances hydrodesulfurization activity, increasing catalytic performance by over 30%.

[0056] 4. The spherical WS2 sheets formed at a hydrothermal temperature of 220°C not only maintain their intact structure, but also partially collapse the ZSM-5 zeolite framework. The doped Ni interacts with the Al element in the ZSM-5 zeolite framework, thereby facilitating the hydrogenation and removal of organic sulfur. The hydrothermal stability of MCM-41, KIT-6, and SBA-15 zeolites is significantly improved after being modified with metal ions, thereby maintaining good framework stability under hydrothermal conditions of 220°C.

[0057] 5. The catalyst material preparation method of the present invention is simple and easy to industrialize. The catalyst with reduced desulfurization efficiency can be regenerated by hydrogen reduction, which has great economic and environmental benefits.

[0058] 6. Resource utilization of spent hydrodesulfurization catalysts can prevent the loss and waste of valuable metals (W, Ni) and reduce their pollution to the environment, which has important environmental and economic significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0060] Figure 1 The XRD patterns of the catalysts synthesized at different hydrothermal temperatures with or without Ni doping on the catalyst support.

[0061] Figure 2 The XPS spectra of catalysts synthesized at different hydrothermal temperatures with or without Ni doping on the catalyst support.

[0062] Figure 3 SEM spectra of the catalysts synthesized at different hydrothermal temperatures with or without Ni doping on the catalyst support: (ab) SEM spectra of WS2 / Ni-ZSM-5 (160°C); (cd) SEM spectra of WS2 / Ni-ZSM-5 (220°C); (ef) SEM spectra of WS2 / Ni-ZSM-5 (240°C); (gh) SEM spectra of WS2 / ZSM-5 (220°C).

[0063] Figure 4 TEM spectra of the catalysts synthesized with or without Ni doping on the support and at different hydrothermal temperatures after Ni doping: (ab) TEM spectrum of WS2 / Ni-ZSM-5 (160°C); (cd) SEM spectrum of WS2 / Ni-ZSM-5 (220°C); (ef) TEM spectrum of WS2 / Ni-ZSM-5 (240°C); (gh) TEM spectrum of WS2 / ZSM-5 (220°C). DETAILED DESCRIPTION

[0064] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0065] The raw materials used to prepare Ni-doped defective WS2 catalyst are:

[0066] 1) Molecular sieve: It is a kind of artificial synthesis of high silica-alumina ratio zeolite molecular sieve, with unique structure and performance, ZSM-5 molecular sieve has three-dimensional channel structure, its pore system is complex and interconnected, this structure gives it good diffusion performance, ZSM-5 molecular sieve has strong acidity and high acid content, has B acid and L acid site, has larger specific surface area, good structure stability, and adjustable silica-alumina ratio, good catalyst effect, which is beneficial to disperse metal components. And the effective shape, size and tortuosity of the pore of ZSM-5 molecular sieve prevent the formation and accumulation of bulky condensates, limit the formation of large condensation molecules from side reactions, so that ZSM-5 catalyst is not easy to accumulate carbon.

[0067] 2) Nickel salt: In the method of Ni doping in supported WS2 catalyst, hydrothermal one-step method can produce more active sites, large specific surface area and effective pore, which is beneficial to the diffusion of catalyst and improves the catalytic desulfurization efficiency of catalyst; although WS2 has large specific surface area, but the electron mobility of WS2 is low, and the doping of Ni can improve the electron mobility of the catalyst, promote the charge transfer, adjust the electronic structure and adsorption free energy, so as to optimize the desulfurization performance of the catalyst. The doping of Ni is beneficial to the formation of WS2 or MoS2 with multi-layer sheet stacking, increases the active sites of the catalyst, improves the stability of the catalyst, avoids the formation of strong W-O-Al bond and inactive NiAl2O4 spinel through the mutual relationship between the carrier, so as to improve the activity and selectivity of the catalyst.

[0068] 3) Tungstate: As a precursor for synthesizing supported WS2 type catalyst, it has excellent catalytic performance, thermal stability and certain electrophilic oxygen vacancy, which can enhance the catalytic activity of WS2 type catalyst under acidic conditions (adding organic acid during hydrothermal reaction), and the formed WS2-WO3 composite has high light response, which is beneficial to photocatalytic desulfurization.

[0069] 4) Sulfidation agent: It plays an important role in the synthesis of supported WS2 type catalyst, which helps to form the best sulfide interface between different sulfides (Ni3S2 and WS2), change the electronic structure, and increase the active surface area of WS2. The use of sulfidation agent helps to maintain the long-term stability of WS2 nanosheet in acid environment (adding organic acid during hydrothermal reaction), improves the stability of the catalyst, and forms surface defects by doping Ni, which can improve the catalytic activity.

[0070] 5) Inorganic hydroxylamine hydrochloride: It is mainly used as a reducing agent in this experiment, which affects the oxidation state and electronic structure of the catalyst, and is beneficial to the synthesis of WS2-WO3 composite material.

[0071] 6) Organic modifiers: They can enhance the activity and selectivity of the catalyst by changing the surface properties and electronic structure of the catalyst, and can also improve the interaction between the metal and the support and the physicochemical properties of the catalyst, thereby promoting the photothermal synergistic hydrogenation conversion to remove organic sulfur.

[0072] Example 1 Preparation method of Ni-doped defective WS2 catalyst:

[0073] 0.5g ZSM-5, 1.1g (NH4)6H2W 12 O 40 Dissolve xH2O, 1.0g H2NCSNH2, 1.0g CTAB, and 1.0g hydroxylamine hydrochloride in 35mL of deionized water, then add 20mL of formic acid. Stir magnetically at room temperature for 30min, then transfer to a 100mL polytetrafluoroethylene reactor and hydroheat at 220℃ for 18h.

[0074] 0.5g ZSM-5, 1.0g Ni(NO3)2·6H2O, 1.1g (NH4)6H2W 12 O 40 Dissolve xH2O, 1.0 g H2NCSNH2, 1.0 g CTAB, and 1.0 g hydroxylamine hydrochloride in 35 mL of deionized water, then add 20 mL of formic acid. Stir magnetically at room temperature for 30 min, then transfer to a 100 mL polytetrafluoroethylene reactor and hydroheat at 160°C, 220°C, and 240°C for 18 h, respectively.

[0075] The catalyst was naturally cooled to room temperature and then filtered, washed with anhydrous ethanol and deionized water for several times, and the obtained solid was dried in an oven at 70° C. for 12 h to obtain a black powder.

[0076] The black powder was pressed into tablets and passed through a 40-60 mesh sieve. 0.2 g of the sieved black catalyst was placed in a photothermal catalytic reactor, calcined at 320°C in a 5% H2 / N2 atmosphere for 12 h, and cooled to room temperature to synthesize WS2 / ZSM-5, WS2 / Ni-ZSM-5 (160°C), WS2 / Ni-ZSM-5 (220°C) and WS2 / Ni-ZSM-5 (240°C).

[0077] 5% H2, 30ppm CS2, and N2 were used as carrier gases to simulate blast furnace gas. The total flow rate was controlled at 200mL / min and the reaction space velocity was 40000h -1 , the ultraviolet light intensity is 9W, the relative humidity is 6.5%, 0.2g of the prepared catalyst material is placed in a photothermal catalytic reactor, and the catalyst is used to synergistically convert CS2 in blast furnace gas by photothermal reaction.

[0078] Catalyst performance tested at 200°C:

[0079] The CS2 conversion rate of the WS2 / ZSM-5 catalyst was 40% under the condition of hot catalyst only, and 70% after adding UV light. The H2S selectivity was 50% under the condition of hot catalyst only, and 65% after adding UV light.

[0080] The CS2 conversion rate of the WS2 / Ni-ZSM-5 catalyst (160°C) was 50% under hot catalyst alone, and 70% after adding UV light. The H2S selectivity was 60% under hot catalyst alone, and about 80% after adding UV light.

[0081] The WS2 / Ni-ZSM-5 (220°C) catalyst had a CS2 conversion of 70% under hot catalyst conditions alone and 100% after adding UV light. The H2S selectivity was 75% under hot catalyst conditions alone and greater than 99% after adding UV light.

[0082] The CS2 conversion rate of the WS2 / Ni-ZSM-5 (240℃) catalyst was 60% under hot catalyst only, and 80% after adding ultraviolet light. The H2S selectivity was 65% under hot catalyst only, and 85% after adding ultraviolet light.

[0083] Example 2

[0084] The H2S generated by the tail gas is adsorbed by an adsorption column filled with adsorbent to achieve the purification standard. The preparation method and adsorption conditions of the adsorbent are as follows:

[0085] Zinc nitrate was dissolved in a mixture of the organic alcohols methanol and ethylene glycol (30% by volume) to produce a zinc nitrate solution. A molecular sieve ZSM-5 (ZSM-5) and anhydrous ethanol were mixed at a molar ratio of 1:4 to prepare a molecular sieve sol. While stirring, distilled water and the inorganic acid sulfuric acid were added dropwise to ensure a molar ratio of molecular sieve:water:hydrochloric acid of 1:2:0.5. The zinc nitrate solution was mixed with the ZSM-5 molecular sieve sol to produce a precursor solution in which the molar ratio of zinc to molecular sieve was 1:2. The precursor solution was dried in a 110°C oven for 24 hours. After drying and grinding, it was calcined in a muffle furnace at 250°C for 4 hours. The pellet was passed through a 40-60 mesh sieve and 0.2 g was loaded into an 8 mm inner diameter glass reaction tube. The desulfurization efficiency was 100% at a 5% H2 content, a gas flow rate of 20 mL / min, and an adsorption temperature of 80°C.

[0086] Example 3 A cyclic regeneration method for Ni-doped defective WS2 catalyst:

[0087] Take 1.0g of WS2 / ZSM-5, WS2 / Ni-ZSM-5 (160℃), WS2 / Ni-ZSM-5 (220℃) and WS2 / Ni-ZSM-5 (240℃) catalysts with reduced desulfurization efficiency, dry them in an 80℃ oven for 12h, press them into tablets and pass them through a 40-60 mesh sieve, weigh 0.2g of the sieved catalyst and place it in a photothermal catalytic reactor, introduce 5% H2 / N2 at a flow rate of 60mL / min, and pass it at 360℃ and 6MPa for 12h. Then, coal gas was introduced into the photothermal catalyst reactor, and the content of various sulfur-containing substances was measured by Foley chromatography to calculate the content of WS2 / ZSM-5, WS2 / Ni-ZSM-5 (160℃), WS2 / Ni-ZSM-5 (220℃) and

[0088] The regeneration efficiencies of the four WS2 / Ni-ZSM-5 (240°C) catalysts were 70%, 80%, 98% and 85%, respectively. By comparing the performance of the catalyst materials with the first regeneration, the desulfurization performance loss rates of the catalysts with decreased desulfurization efficiency were 5%, 3%, 2% and 2.8%, respectively, after each regeneration.

[0089] The above four catalysts are generally the most economically valuable after being regenerated with hydrogen once, twice, four times and three times respectively.

[0090] Example 4 A method for resource utilization of spent hydrodesulfurization catalyst:

[0091] 10.0g of spent hydrodesulfurization catalyst was pretreated by calcining it in a muffle furnace at 650°C in air for 4 hours. Ultrasonic immersion at 80°C for 60 minutes using 2.0mol / L sulfuric acid at a solid-to-liquid ratio of 10:1 resulted in a leaching rate of over 98% for valuable metals. Furthermore, 1.5mol / L ammonium hydroxide, kerosene as a diluent, and 6% n-decanol as a modifier, with a liquid-to-organic phase ratio of 1:1, resulted in extraction rates exceeding 98% for both tungsten and nickel. For the tungsten-containing extraction solution, 0.5 mol / L NH4OH (or NaOH) is added and stirred on an electromagnetic stirrer at 90°C until dry, and finally ammonium tungstate or sodium tungstate compound with a purity greater than 99% is obtained; for the nickel-containing extraction solution, 0.45 mol / L H2C2O4 (or H2SO4, HCl) is added as a precipitant, the molar ratio of oxalic acid or sulfuric acid to nickel ions is 1:2, and precipitation recovery is carried out in an environment of 50°C, and finally nickel oxalate or nickel sulfate with a purity greater than 98% is obtained.

[0092] Example 5 Preparation method of Ni-doped defective WS2 catalyst:

[0093] Combine 0.5gMCM-41, 1.0gNi(NO3)2·6H2O, 1.1g(NH4)6H2W 12 O40 Dissolve xH2O, 1.0 g CH3CSNH2, 1.0 g ascorbic acid, and 1.0 g hydroxylamine hydrochloride in 35 mL of deionized water, then add 20 mL of acetic acid. Stir magnetically at room temperature for 60 min, then transfer to a 100 mL polytetrafluoroethylene reactor and hydroheat at 220°C for 18 h.

[0094] The catalyst was naturally cooled to room temperature and then filtered, washed with anhydrous ethanol and deionized water for several times, and the obtained solid was dried in an oven at 70° C. for 12 h to obtain a black powder.

[0095] The black powder was pressed into tablets and passed through a 40-60 mesh sieve. 0.2 g of the sieved black catalyst was placed in a photothermal catalytic reactor, calcined at 320°C in a 5% H2 / N2 atmosphere for 12 h, and cooled to room temperature to synthesize WS2 / Ni-MCM-41.

[0096] The catalyst performance was tested at 200°C: the CS2 conversion rate of the WS2 / Ni-MCM-41 catalyst was 45% under only hot catalyst, and 60% after adding ultraviolet light. The H2S selectivity was 55% under only hot catalyst, and 70% after adding ultraviolet light.

[0097] Example 6 Preparation method of Ni-doped defective WS2 catalyst:

[0098] Combine 0.5gKIT-6, 1.0gNi(NO3)2·6H2O, 1.1g(NH4)6H2W 12 O 40 ·xH2O, 1.0 g CH3CSNH2, 1.0 g N, O-dimethylhydroxylamine hydrochloride and 1.0 g CTAB were dissolved in 35 mL of deionized water, and 20 mL of acetic acid was added. The mixture was magnetically stirred at room temperature for 60 min, then transferred to a 100 mL polytetrafluoroethylene reactor, hydroheated at 220°C for 18 h, naturally cooled to room temperature, and filtered. The mixture was washed with anhydrous ethanol and deionized water several times, and the obtained solid was dried in an oven at 70°C for 12 h to synthesize WS2 / Ni-KIT-6.

[0099] The WS2 / Ni-KIT-6 catalyst was pressed into a pellet and passed through a 40-60 mesh sieve. 0.2 g of the sieved catalyst was placed in a photothermal catalytic reactor and pre-sulfurized at 400°C in a 5% H2 / CS2 atmosphere for 4 hours. The catalyst was then cooled to room temperature to synthesize WS2 / Ni-KIT-6. 5% H2, 30 ppm CS2, and N2 were used as carrier gases to simulate blast furnace gas. The total flow rate was controlled at 200 mL / min, and the reaction space velocity was 40,000 h -1, the ultraviolet light intensity is 9W, the relative humidity is 6.5%, 0.2g of the prepared catalyst material is placed in a photothermal catalytic reactor, and the catalyst is used to synergistically convert CS2 in blast furnace gas by photothermal reaction.

[0100] The catalyst performance was tested at 200°C. The CS2 conversion rate of the WS2 / Ni-KIT-6 catalyst was 55% under only hot catalyst conditions, and 70% after adding ultraviolet light. The H2S selectivity was 60% under only hot catalyst conditions, and 75% after adding ultraviolet light.

[0101] Example 7 Preparation method of Ni-doped defective WS2 catalyst:

[0102] 0.5g SBA-15, 1.0g Ni(NO3)2·6H2O, 1.1g (NH4) 10 H2(W2O7)6, 1.0gCH3CSNH2, 1.0gN,O-dimethylhydroxylamine hydrochloride and 1.0g ascorbic acid were dissolved in 35mL deionized water, and then 20mL formic acid was added. After magnetic stirring at room temperature for 60min, the mixture was transferred to a 100mL polytetrafluoroethylene reactor and hydroheated at 220℃ for 18h. After natural cooling to room temperature, it was filtered and washed with anhydrous ethanol and deionized water several times. The obtained solid was dried in an oven at 70℃ for 12h to synthesize WS2 / Ni-SBA-15.

[0103] 5% H2, 30ppm CS2, and N2 were used as carrier gases to simulate blast furnace gas. The total flow rate was controlled at 200mL / min and the reaction space velocity was 40000h -1 , the ultraviolet light intensity is 9W, the relative humidity is 6.5%, 0.2g of the prepared catalyst material is placed in a photothermal catalytic reactor, and the catalyst is used to synergistically convert CS2 in blast furnace gas by photothermal reaction.

[0104] The catalyst performance was tested at 200°C. The CS2 conversion rate of the WS2 / Ni-SBA-15 catalyst was 60% under only hot catalyst conditions, and 75% after adding ultraviolet light. The H2S selectivity was 70% under only hot catalyst conditions, and 85% after adding ultraviolet light.

[0105] The composition and crystallinity of the catalyst were characterized by XRD. Figure 1 The XRD patterns of the prepared catalysts show that all samples exhibit diffraction peaks encompassing the (002) and (100) crystal planes of WS2 and the (200) crystal plane of WO3, while the (010) crystal plane of Ni3S2 is present only in the Ni-doped catalyst. After Ni doping the catalyst support, the peak intensity of WS2 significantly increases, while the peak intensity of WO3 decreases. With increasing hydrothermal temperature after Ni doping, the peak intensity of WO3 gradually decreases, while the peak intensity of WS2 increases first and then decreases, while the peak intensity of Ni3S2 gradually increases.

[0106] The synthesized catalysts were analyzed using X-ray photoelectron spectroscopy (XPS) to characterize the chemical composition and valence states of the elements present. Figure 2 (a) S2p XPS spectrum of the prepared catalyst material. The two peaks in the S2p orbital between 162.0 and 163.4 eV are attributed to S-W bonds. Ni doping shifts the S2p peak. At 220°C, Ni doping increases the intensities of both W and S peaks, indicating increased WS2 formation on the catalyst surface, leading to the formation of WO3. Figure 2 (b) is the W 4f XPS spectrum of the prepared catalyst material. The two peaks at 35.6eV to 38.2eV in the W 4f orbital correspond to the WO bond, indicating that WO3 exists on the surface of the sample during the preparation process, which belongs to W 6 + , 32.5eV~34.8eV, the two peaks correspond to the WS bond, indicating that the synthesized catalyst is W 4+ WS2.

[0107] SEM was used to further evaluate the surface morphology and chemical content of the prepared catalysts. Scanning SEM and EDS elemental maps further revealed the distribution of Si, Al, O, Ni, W, and S elements in the catalyst structures of WS2 / ZSM-5, WS2 / Ni-ZSM-5 (160°C), WS2 / Ni-ZSM-5 (220°C), and WS2 / Ni-ZSM-5 (240°C). The energy spectrum clearly shows the main distribution of O, Si, W, and S elements on the catalyst surface. Figure 3 (g) and (c), it can be seen that after adding Ni, the flake-stacked spherical WS2 is more regular and the surface is smoother. Figure 3 As shown in (a), (c), and (e), the spherical WS2 formed becomes more regular as the hydrothermal temperature increases. However, at 240°C, the regular spheres begin to flake off, forming flakes. At 220°C and 240°C, in addition to the spherical WS2, SiO2 rods are also formed. This indicates that the hydrothermal temperature has reached a point where the ZSM-5 framework collapses. At high temperatures, the elements within the ZSM-5 framework recombine, with Si reacting with oxygen in the catalyst to form SiO2, which is independently distributed around the synthesized catalyst. The detached Al from the framework interacts with the doped Ni. The flake-like, stacked spherical WS2 formed at 220°C not only maintains its integrity, but also partially collapses the ZSM-5 framework. The doped Ni interacts with the Al within the ZSM-5 framework, facilitating hydrogenation and organic sulfur removal.

[0108] XRD analysis has been performed to confirm the crystal structure of the synthesized material. It is known that doping Ni on the catalyst support does not change its original crystal structure, but only adds new lattice parameters to the original crystal structure. Figure 4 (h) and (d), it can be seen that after doping Ni on the catalyst support, the lattice spacing of WS2 and WO3 formed has no effect. Figure 4 (a), (c), and (e) show that after Ni doping, Ni2S3 lattice fringes appear in addition to WS2 and WO3 lattice fringes as the hydrothermal temperature increases. After Ni doping the catalyst support, the catalyst synthesized at 160°C exhibits more WO3 lattice fringes, the catalyst synthesized at 220°C exhibits more WS2 lattice fringes, and the catalyst synthesized at 240°C exhibits more Ni2S3 lattice fringes. TEM images reveal numerous defects and distortions on the basal surface and edges.

[0109] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a Ni-doped defective WS2 catalyst, characterized in that: The following steps are involved: S11. Dissolve the molecular sieve, nickel salt, tungstate, sulfiding agent, inorganic hydroxylamine hydrochloride, and organic modifier in deionized water, add a certain amount of organic acid, and hydrothermally react at 220°C for a certain time; The molecular sieve is ZSM-5, and the organic modifier is selected from hexadecyltrimethylammonium bromide and ascorbic acid; S12. After the reaction was completed, the product was cooled to room temperature, filtered, washed with deionized water and anhydrous ethanol several times, and dried to obtain a solid product; S13. Place the solid product in a photothermal catalytic reactor and reduce it with 2% to 10% H2 at 300°C to 350°C to obtain a Ni-doped defective WS2 catalyst.

2. The method for preparing a Ni-doped defective WS2 catalyst according to claim 1, wherein: In S11, The nickel salt is selected from nickel nitrate, nickel sulfate, and nickel hydroxide; The tungstate is selected from ammonium metatungstate and sodium tungstate; The vulcanizing agent is selected from thiourea and thioacetamide; The inorganic hydroxylamine hydrochloride is selected from hydroxylamine hydrochloride and N,O-dimethylhydroxylamine hydrochloride; The organic acid is selected from formic acid, acetic acid, sulfuric acid and phosphoric acid.

3. The method for preparing a Ni-doped defective WS2 catalyst according to claim 2, wherein: The mass ratio of the molecular sieve: nickel salt: tungstate: sulfiding agent: inorganic hydroxylamine hydrochloride: organic modifier is (0.1~1): (1~2): (1~2): (1~2): (1~2): (1~2); The solid-liquid ratio of the molecular sieve to deionized water is 1 / 200-1 / 50, and the solid-liquid ratio of the molecular sieve to the organic acid is 0.0082-0.0273.

4. The method for preparing a Ni-doped defective WS2 catalyst according to claim 1, wherein: In S11, the hydrothermal reaction time is 7 h to 24 h.

5. An application of a Ni-doped defective WS2 catalyst, characterized in that: The following steps are involved: In a photothermal catalytic reactor, a certain amount of Ni-doped defective WS2 catalyst prepared by the method according to any one of claims 1 to 4 was taken, and the flow rate was 200 mL / min and the reaction space velocity was 30000~40000 h -1 , blast furnace gas with ultraviolet light intensity of 7~10W is subjected to photothermal synergistic hydrogenation conversion at 120℃~200℃ to obtain H2S; Then the H2S is removed through adsorption purification.

6. The use of a Ni-doped defective WS2 catalyst according to claim 5, characterized in that: The amount of the Ni-doped defective WS2 catalyst used is 0.2 g.

7. A method for recycling Ni-doped defective WS2 catalyst, characterized in that: The specific steps are: The Ni-doped defective WS2 catalyst with decreased desulfurization efficiency after application as described in any one of claims 5-6 is regenerated under a hydrogen atmosphere of 320° C. to 470° C. and 1.6 to 9.8 MPa.

8. The recycling regeneration method of a Ni-doped defective WS2 catalyst according to claim 7, characterized in that: The regeneration conditions are as follows: introducing 2% to 5% hydrogen at a flow rate of 20 to 80 mL / min, using N2 as a protective gas, and reacting for 12 to 36 hours.

9. A method for resource utilization of spent hydrodesulfurization catalyst, characterized in that: The specific steps are as follows: S21. The Ni-doped defective WS2 catalyst failed after the regeneration method according to any one of claims 7-8 was calcined in an air atmosphere at 500 ℃ ~ 800 ℃ for 3h ~ 6h; S22. A 0.1 mol / L to 3.0 mol / L inorganic acid aqueous solution was ultrasonically impregnated with the spent Ni-doped defective WS2 catalyst at a solid-to-liquid ratio of 15:1 to 10:1 at 50°C to 100°C for 30-60 min, and the residue and filtrate were separated by filtration. S23 was added to the filtrate at a concentration of 0.5mol / L ~ 2.0mol / L of a quaternary ammonium salt aqueous solution, the reaction solution was added to 60% to 65% of the total volume of kerosene, the reaction solution was added to 5% to 7.5% of the total volume of n-decanol; The ratio of the aqueous phase to the organic phase is 1:1 to 1:2, and a tungsten-containing extract and a nickel-containing extract are obtained; S24. Adding an aqueous solution of NH4OH or NaOH to the tungsten-containing extract, stirring on an electromagnetic stirrer at 80°C to 100°C until dry to obtain an ammonium tungstate or sodium tungstate compound having a purity greater than 99%; Add H2C2O4 or H2SO4 or HCl solution as a precipitant to the nickel-containing extract, and perform precipitation recovery in an environment of 40°C to 60°C to obtain nickel oxalate, nickel sulfate or nickel chloride with a purity greater than 98%.

10. The method for resource utilization of a spent hydrodesulfurization catalyst according to claim 9, characterized in that: In step S24, the concentration of the NH4OH or NaOH aqueous solution is 0.1 mol / L to 1.0 mol / L, and the molar ratio of hydroxide to tungstate ion is 1:1 to 1:3; The concentration of the H2C2O4 or H2SO4 or HCl solution is 0.1 mol / L~1.0 mol / L, the molar ratio of oxalate to nickel ion is 1:1~1:2, the molar ratio of sulfate to nickel ion is 1:1~1:3, and the molar ratio of chloride ion to nickel ion is 3:1~2:1.

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