Hydrogen peroxide preparation method based on efficient gas-liquid-solid circulation mixed flow reaction

Abstract

The invention belongs to the technical field of hydrogen peroxide preparation, and particularly relates to a hydrogen peroxide preparation method based on efficient gas-liquid-solid circulation mixed flow reaction, and the preparation method comprises the following steps: S1, mixing 2-ethyl anthraquinone and 2-amyl anthraquinone to form a solute, mixing C10 heavy aromatics and tetrabutyl urea to form a solvent, and carrying out solid-liquid-solid circulation mixed flow reaction on the solvent; mixing the solute and the solvent to prepare a working solution; s2, adding the working solution, hydrogen and a solid hydrogenation catalyst into a hydrogenation tower in a three-phase manner, and carrying out a hydrogenation reaction to obtain a hydrogenated solution containing anthrahydroquinone; s3, the hydrogenated liquid is added into an oxidation tower to react with oxygen, and oxidation liquid containing hydrogen peroxide is obtained through the reaction; s4, extracting the oxidation liquid in an extraction tower to obtain a hydrogen peroxide crude product; and S5, purifying and removing impurities from the hydrogen peroxide crude product to obtain an industrial-grade hydrogen peroxide finished product. According to the invention, safer C10 high-purity aromatic hydrocarbon is adopted to replace C9 heavy aromatic hydrocarbon, and a tetrabutyl urea solvent with better solubility is adopted to replace trioctyl phosphate, so that the explosion concentration lower limit is improved, and the system safety is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen peroxide preparation, and particularly relates to a method for preparing hydrogen peroxide based on a high-efficiency gas-liquid-solid circulating mixed flow reaction. Background Art

[0002] The anthraquinone process is currently the primary method for industrially producing hydrogen peroxide and is the most widely commercialized and applied production method. It is widely adopted for its efficiency, safety, and cost-effectiveness. The process involves the following steps: First, anthraquinone is dissolved in an organic solvent and reduced to anthraquinone hydride through catalytic hydrogenation. The hydride is then exposed to oxygen in the air for an oxidation reaction, generating hydrogen peroxide and simultaneously regenerating anthraquinone. Finally, the hydrogen peroxide is extracted with water and purified through distillation and other processes to produce the finished product.

[0003] However, due to the lack of basic data and insufficient research on reaction kinetics and thermodynamics in the fully mixed flow reactor for preparing hydrogen peroxide by the hydrogenation anthraquinone method, as well as the technical barriers faced by foreign companies, its production capacity is restricted by the supply of foreign process technology, and it is unable to guarantee the stable growth of the domestic hydrogen peroxide industry.

[0004] At the same time, hydrogen peroxide is easy to decompose, release heat, and release a large amount of oxygen. If the heat and oxygen are not removed in time, the temperature will continue to rise, which will intensify the decomposition until the reaction is irreversible and may cause an explosion. Especially for the production of high-concentration hydrogen peroxide, its intrinsic safety factor needs to be increased. Summary of the Invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a method for preparing hydrogen peroxide based on an efficient gas-liquid-solid circulating mixed flow reaction, which adopts a safer C 10 High-purity aromatics replace C9 heavy aromatics, and tetrabutyl urea solvent with better solubility replaces trioctyl phosphate to form a safer working fluid system. Combined with the optimized design of key equipment and internal components such as the hydrogenation tower, oxidation tower, and extraction tower, the system safety is greatly increased and the reaction efficiency is improved.

[0006] The specific technical solution adopted in the present invention is:

[0007] A method for preparing hydrogen peroxide based on a high-efficiency gas-liquid-solid circulating mixed flow reaction, the method comprising the following steps:

[0008] S1, 2-ethylanthraquinone and 2-amylanthraquinone in a mass ratio of 1-6:1 are mixed to form a solute, C10 heavy aromatic hydrocarbon and tetrabutyl urea in a mass ratio of 2-6:1 are mixed to form a solvent, and the solute and solvent are mixed in a mass ratio of 2.5:5.5:1 to form a working solution;

[0009] S2, adding the working liquid, hydrogen and solid hydrogenation catalyst into a hydrogenation tower in three phases, mixing and performing a hydrogenation reaction to obtain a hydrogenated liquid containing anthrahydroquinone;

[0010] S3, adding the hydrogenated liquid to the oxidation tower to react with oxygen to obtain an oxidation liquid containing hydrogen peroxide;

[0011] S4, extracting the oxidizing liquid in an extraction tower to obtain a crude hydrogen peroxide product;

[0012] S5. Purify and remove impurities from the crude hydrogen peroxide to obtain an industrial-grade hydrogen peroxide product.

[0013] The gas phase input end of the hydrogenation tower is provided with a gas phase distributor, which has a disc-shaped structure. The gas phase input end of the hydrogenation tower is connected to the center of the gas phase distributor. The gas phase distributor is provided with multiple groups of diversion holes in a ring array, and the diameter of the diversion holes increases step by step from the center of the gas phase distributor to the periphery of the gas phase distributor.

[0014] A plurality of groups of coolers are arranged in the oxidation tower at intervals along the vertical direction. The liquid phase input end of the oxidation tower is arranged near the top of the oxidation tower. The liquid phase input end of the oxidation tower is provided with a plurality of rows of perforated tube-type liquid distributors.

[0015] The extraction tower is provided with a coalescer, the packing layer of the coalescer includes a highly hydrophilic coalescing packing layer and a highly hydrophobic coalescing packing layer, and the highly hydrophobic coalescing packing layer is located above the highly hydrophilic coalescing packing layer.

[0016] The preparation method of the solid hydrogenation catalyst comprises the following steps:

[0017] A1. Preparation of active seed solution: A noble metal salt solution and a transition metal salt solution are mixed at a metal element ratio of 1:0.3-0.5 to obtain a mixed solution, wherein the total metal ion concentration in the mixed solution is 0.1-0.3 mol / L;

[0018] A2. Adjust the pH value of the mixed solution to 8-9, then add ethylenediaminetetraacetic acid (EDTA) in an amount of 1.2-1.5 times the amount of the total metal ion substance, and heat and stir to obtain an active seed solution;

[0019] B1. Preparation of carrier core: γ-alumina powder is used as the core matrix, 5%-10% of sesbania powder is added, the mixture is evenly mixed, and water is added to form a slurry. The slurry is granulated into particles with a diameter of 1.5-2.5 mm, and dried to obtain a precursor body;

[0020] B2. Place the precursor body in a heating furnace and calcine it at a temperature of 500-600°C for 3-5 hours. After cooling, obtain the carrier core;

[0021] C1. Preparation of carrier shell: Tetraethyl orthosilicate, ethanol, and deionized water were mixed in a volume ratio of 1:1-2:2-5, and the pH value was adjusted to 2-3. The mixture was stirred evenly, and polyvinyl pyrrolidone was added. The silica sol was obtained by ultrasonic dispersion.

[0022] C2. Immerse the core of the carrier obtained in step B2 in silica sol for 40-60 minutes, remove it and dry it, and then calcine it at 300-400°C for 2-3 hours to obtain a core-shell structure carrier;

[0023] D1. Add the core-shell structured carrier obtained in step C2 to the active seed solution obtained in step A2 and immerse for 12-24 hours, then wash the carrier to obtain a loaded intermediate;

[0024] D2. Add the loaded intermediate to hydrazine hydrate to react and obtain a catalyst precursor. Place the catalyst precursor in a tubular furnace and heat it at 200-300° C. for 2-3 hours under a hydrogen atmosphere. After cooling, introduce nitrogen for passivation treatment for 20-40 minutes to obtain a solid hydrogenation catalyst.

[0025] The amount of hydrazine hydrate added in step D2 is 1.5-2 times the amount of the total metal ion substance in the loaded intermediate.

[0026] The inner diameter of the hydrogenation tower is 4800-5600 mm, and the operating pressure of the hydrogenation tower is 0.11-0.14 MPa.

[0027] A hydrogen peroxide production system based on a high-efficiency gas-liquid-solid circulating mixed-flow reaction comprises a working liquid preparation tank, a hydrogenation tower, an oxidation tower, an extraction tower, and a purification tower. The output end of the working liquid preparation tank is connected to the liquid phase input end of the hydrogenation tower, the gas phase input end of the hydrogenation tower is connected to the output end of a hydrogen compressor, the solid phase input end of the hydrogenation tower is connected to the output end of a catalyst storage bin, the liquid phase output end of the hydrogenation tower is connected to the liquid phase input end of the oxidation tower, the gas phase input end of the oxidation tower is connected to an air compressor, the liquid phase output end of the oxidation tower is connected to the dispersed phase input end of the extraction tower, the continuous phase input end of the extraction tower is connected to a pure water supply end, and the hydrogen peroxide output end of the extraction tower is connected to the input end of the purification tower.

[0028] A regenerator is further provided between the working liquid preparation tank and the hydrogenation tower. The output end of the working liquid preparation tank is connected to the liquid phase input end of the regenerator, the output end of the regenerator is connected to the liquid phase input end of the hydrogenation tower, and the circulation output end of the hydrogenation tower is connected to the circulation input end of the regenerator.

[0029] The beneficial effects of the present invention are:

[0030] 1. The solvent of the traditional working fluid prepared with hydrogen peroxide is generally a mixed solvent of trioctyl phosphate and C9 aromatic hydrocarbons. However, the lower explosion concentration limit of the condensed phase of trioctyl phosphate, hydrogen peroxide and water is about 44-45%, which cannot meet the requirements of high-concentration hydrogen peroxide production. In addition, C9 aromatic hydrocarbons have a low flash point, which is very likely to cause flash explosions in the oxidation part, thereby causing fire and explosion accidents.

[0031] Therefore, the present invention uses tetrabutyl urea and C 10 The solvent system obtained by mixing heavy aromatic hydrocarbons, the lower limit of explosion concentration of the condensed phase of tetrabutyl urea and hydrogen peroxide is 50%, and the density of tetrabutyl urea is about 0.88g / m 3 Without significantly increasing the specific gravity of the working fluid, the total anthraquinone solubility can be increased to 200-240g / L. At the same hydrogenation level, a higher hydrogenation efficiency can be maintained, further achieving a hydrogenation efficiency of 12-14.3g / L. At the same time, the flash point of the working fluid is increased from 45°C to 66°C, reducing the working fluid from Class B to Class C hazardous chemicals, thereby improving the safety of the device.

[0032] In addition, because tetrabutyl urea has a large distribution coefficient and surface tension, the organic phase and the aqueous phase can be quickly separated, which is beneficial to the extraction process.

[0033] 2. The present invention optimizes the structure and operating parameters of the hydrogenation tower. In the prior art, the inner diameter of the hydrogenation tower is 6200 mm, which is relatively large, resulting in uneven flow field distribution inside the hydrogenation tower, causing short circuit in the hydrogenation tower, excessive hydrogenation of the backwash hydrogenation liquid, and increased loss of the working fluid.

[0034] Therefore, after optimization, the inner diameter of the hydrogenation tower was reduced from the original 6200mm to 5200mm. At the same time, nitrogen was added to the circulating hydrogen in the hydrogenation tower for dilution. By diluting the hydrogen concentration, the intensity of the reaction can be effectively controlled.

[0035] At the same time, the hydrogenation tower of the present invention is equipped with a gas phase distributor with fine central pores and coarse peripheral pores. The diverter holes on a conventional gas phase distributor have the same diameter. When hydrogen is fed into the hydrogenation tower, the diverter holes near the gas phase input end of the gas phase distributor are subject to higher pressure, while the diverter holes farther away are subject to lower pressure. This results in a higher hydrogen flow rate near the gas phase input end and a lower hydrogen flow rate at the farther holes, creating a flow field deviation with overshoot at the center and insufficient flow at the edges, which is not conducive to sufficient mixing between hydrogen and the working fluid. Therefore, a variable pore size gradient distribution with fine central pores and coarse peripheral pores is adopted to ensure that the flow rates of each diverter hole are essentially the same.

[0036] 3. This invention optimizes the oxidation tower structure and operating parameters, reducing the equipment's outer diameter from 8,600 mm to 6,900 mm. The resulting reaction oxidation efficiency reaches a maximum of 11.27 g / L, and the oxidation yield remains consistently above 95%.

[0037] Since the oxidation reaction is a reaction between a large amount of organic matter and oxygen in the air, if the temperature is not well controlled, it is easy to form a high-temperature flammable gas mixture atmosphere close to or exceeding the flash point of the combustible. If the static electricity is not discharged in time, it is very easy to cause a flash fire accident, increasing the risk of operation. Therefore, in the present invention, multiple groups of coolers are arranged at intervals in the oxidation tower to achieve segmented and precise temperature control for the oxidation reaction and avoid local overheating in the tower. The multi-row perforated tubular liquid distributor can evenly disperse the liquid phase into thin streams or droplets, covering the entire tower cross-section, so that the liquid forms a uniform liquid film along the surface of the filler, enhancing the gas-liquid mass transfer efficiency and improving the oxidation reaction rate and conversion rate.

[0038] 4. The inner diameter of the extraction tower in the present invention is optimized from the original 7000mm to 5400mm. After optimization, more than 20% of the hydrogen peroxide inventory in the extraction tower is less than 120m 3 , more than 20% of the hydrogen peroxide inventory in the device (including the extraction tower and hydrogen peroxide tank) is less than 150m 3 , greatly reducing the danger of the device area. The optimized size is more reasonable, while meeting the requirement of quickly outputting 45% of the product, increasing the separation efficiency of the extraction tower, reducing the amount of hydrogen peroxide stored in the tower, increasing system safety, and achieving fast and safe material withdrawal.

[0039] The highly hydrophilic coalescing filler layer can preferentially capture aqueous phase droplets, promote the coalescence and growth of aqueous phase droplets through surface tension, and accelerate the separation of aqueous phase from organic phase; the highly hydrophobic coalescing filler layer has affinity for organic phase, can capture and coalesce organic phase droplets, and reduce the entrainment of organic phase in aqueous phase.

[0040] The combination of two layers of fillers forms a step-by-step coalescence mechanism, which can make the separation of the aqueous phase and the organic phase more thorough compared to a single filler layer, reduce the emulsification degree at the interface between the two phases, and improve the purity of the hydrogen peroxide aqueous solution after extraction and the recovery rate of the extractant.

[0041] 5. The solid hydrogenation catalyst of the present invention has a core-shell structure, with the core layer wrapped by the porous silica shell layer, which inhibits the agglomeration or sintering of the core particles at high temperatures and is suitable for high-temperature reactions in the roasting process and hydrogenation reaction.

[0042] At the same time, the shell can also prevent impurities in the reactants (such as sulfur and phosphorus) from directly contacting the core active sites, thereby extending the service life of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The figure is a flow chart of the hydrogen peroxide production process of the present invention.

[0044] Figure 2 Schematic diagram of the structure of the hydrogenation tower;

[0045] Figure 3Schematic diagram of the cross-sectional structure of the gas phase distributor;

[0046] Figure 4 Schematic diagram of the top view of the gas phase distributor;

[0047] Figure 5 It is the structural diagram of the oxidation tower;

[0048] Figure 6 Schematic diagram of the structure of the liquid distributor;

[0049] Figure 7 Schematic diagram of the structure of the extraction tower;

[0050] Figure 8 It is a structural diagram of the packing layer of the coalescer;

[0051] 1. Gas phase distributor, 2. Diverter hole, 3. Cooler, 4. Liquid distributor, 5. Coalescer, 6. Highly hydrophilic coalescing packing layer, 7. Highly hydrophobic coalescing packing layer. DETAILED DESCRIPTION

[0052] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0053] In a specific embodiment, the present invention provides a method for preparing hydrogen peroxide based on an efficient gas-liquid-solid circulating mixed flow reaction, the preparation method comprising the following steps:

[0054] S1, 2-ethylanthraquinone and 2-amylanthraquinone in a mass ratio of 1-6:1 are mixed to form a solute, C10 heavy aromatic hydrocarbon and tetrabutyl urea in a mass ratio of 2-6:1 are mixed to form a solvent, and the solute and solvent are mixed in a mass ratio of 2.5:5.5:1 to form a working solution;

[0055] S2, adding the working liquid, hydrogen and solid hydrogenation catalyst into a hydrogenation tower in three phases, mixing and performing a hydrogenation reaction to obtain a hydrogenated liquid containing anthrahydroquinone;

[0056] S3, adding the hydrogenated liquid to the oxidation tower to react with oxygen to obtain an oxidation liquid containing hydrogen peroxide;

[0057] S4, the oxidizing liquid is extracted in an extraction tower to obtain a crude hydrogen peroxide product;

[0058] S5. Purify and remove impurities from the crude hydrogen peroxide to obtain an industrial-grade hydrogen peroxide product.

[0059] The solvent for traditional working fluids prepared with hydrogen peroxide is generally a mixed solvent of trioctyl phosphate and C9 aromatic hydrocarbons. However, the lower explosion limit of the condensed phase of a three-phase mixture of trioctyl phosphate, hydrogen peroxide, and water is approximately 44-45%, which cannot meet the requirements for high-concentration hydrogen peroxide production. In addition, C9 aromatic hydrocarbons have a low flash point, making flash explosions in the oxidation portion extremely likely to cause fires and explosions.

[0060] Therefore, the present invention uses a solvent system made from a mixture of tetrabutylurea and C10 heavy aromatic hydrocarbons. The lower explosion limit of the condensed phase of the mixture of tetrabutylurea and hydrogen peroxide is 50%. At the same time, the density of tetrabutylurea is approximately 0.88 g / m3, which does not significantly increase the specific gravity of the working fluid. The total anthraquinone solubility can be increased to 200-240 g / L. Under the same hydrogenation degree, a higher hydrogenation efficiency can be maintained, further achieving a hydrogenation efficiency of 12-14.3 g / L. At the same time, the flash point of the working fluid is increased from 45°C to 66°C, thereby reducing the working fluid from a Class B hazardous chemical to a Class C hazardous chemical, improving the safety of the device.

[0061] In addition, because tetrabutyl urea has a large distribution coefficient and surface tension, the organic phase and the aqueous phase can be quickly separated, which is beneficial to the extraction process.

[0062] like Figure 2-4 As shown, the gas phase input end of the hydrogenation tower is provided with a gas phase distributor 1, and the gas phase distributor 1 is a disc-shaped structure. The gas phase input end of the hydrogenation tower is connected to the center of the gas phase distributor 1, and the gas phase distributor 1 is provided with multiple groups of diversion holes 2 in a ring array. The diameter of the diversion hole 2 tends to increase step by step from the center of the gas phase distributor 1 to the peripheral side of the gas phase distributor 1.

[0063] The present invention optimizes the structure and operating parameters of the hydrogenation tower. In the prior art, the inner diameter of the hydrogenation tower is 6200 mm, which is relatively large, resulting in uneven flow field distribution inside the hydrogenation tower, causing short circuit in the hydrogenation tower, excessive hydrogenation of the backwash hydrogenation liquid, and increased loss of the working fluid.

[0064] Therefore, after optimization, the inner diameter of the hydrogenation tower was reduced from the original 6200mm to 5200mm. At the same time, nitrogen was added to the circulating hydrogen in the hydrogenation tower for dilution. By diluting the hydrogen concentration, the intensity of the reaction can be effectively controlled.

[0065] At the same time, the hydrogenation tower of the present invention is equipped with a gas phase distributor 1 with fine central pores and coarse peripheral pores. The diverter holes 2 on the conventional gas phase distributor 1 have the same pore size. When hydrogen is fed into the hydrogenation tower from the gas phase input end, the diverter holes 2 on the gas phase distributor 1 near the gas phase input end are subject to higher pressure, while the diverter holes 2 farther away are subject to lower pressure. This results in a higher hydrogen flow rate near the gas phase input end and a lower hydrogen flow rate at the farther holes, resulting in a flow field deviation with overshoot at the center and insufficient flow at the edges, which is not conducive to sufficient mixing between hydrogen and the working fluid. Therefore, a variable pore size gradient distribution with fine central pores and coarse peripheral pores is adopted to ensure that the flow rate of each diverter hole 2 is essentially the same.

[0066] like Figure 5-6As shown, multiple groups of coolers 3 are arranged at intervals along the vertical direction in the oxidation tower, the liquid phase input end of the oxidation tower is arranged near the top of the oxidation tower, and the liquid phase input end of the oxidation tower is provided with multiple rows of perforated tube-type liquid distributors 4.

[0067] The present invention optimizes the oxidation tower structure and operating parameters, reducing the equipment's outer diameter from 8,600 mm to 6,900 mm. The resulting reaction oxidation efficiency can reach a maximum of 11.27 g / L, and the oxidation yield remains stable at over 95%.

[0068] Since the oxidation reaction is a reaction between a large amount of organic matter and oxygen in the air, poor temperature control can easily form a high-temperature, flammable phase mixture atmosphere close to or exceeding the flash point of the combustible. If static electricity is not discharged in time, it can easily lead to flash fire accidents, increasing the risk of operation. Therefore, in the present invention, multiple groups of coolers 3 are arranged at intervals in the oxidation tower to achieve segmented and precise temperature control for the oxidation reaction and avoid local overheating in the tower. The multi-row perforated tubular liquid distributor 4 can evenly disperse the liquid phase into thin streams or droplets, covering the entire tower cross-section, so that the liquid forms a uniform liquid film along the surface of the filler, enhancing the gas-liquid mass transfer efficiency and improving the oxidation reaction rate and conversion rate.

[0069] like Figure 7-8 As shown, a coalescer 5 is provided in the extraction tower, and the packing layer of the coalescer 5 includes a highly hydrophilic coalescing packing layer 6 and a highly hydrophobic coalescing packing layer 7 .

[0070] The internal diameter of the extraction tower in this invention has been optimized from 7000mm to 5400mm. After optimization, the hydrogen peroxide inventory of more than 20% in the extraction tower is less than 120m³, and the hydrogen peroxide inventory of more than 20% in the device (including the extraction tower and hydrogen peroxide tank) is less than 150m³, significantly reducing the risk of the device area. The optimized dimensions are more reasonable, while also meeting the requirement for rapid 45% product output, increasing the separation efficiency of the extraction tower, reducing the hydrogen peroxide inventory in the tower, improving system safety, and enabling fast and safe material withdrawal.

[0071] The highly hydrophilic coalescing packing layer 6 can preferentially capture aqueous phase droplets, promote the coalescence and growth of aqueous phase droplets through surface tension, and accelerate the separation of aqueous phase from organic phase; the highly hydrophobic coalescing packing layer 7 has affinity for organic phase, can capture and coalesce organic phase droplets, and reduce the entrainment of organic phase in aqueous phase.

[0072] The combination of two layers of fillers forms a step-by-step coalescence mechanism, which can make the separation of the aqueous phase and the organic phase more thorough compared to a single filler layer, reduce the emulsification degree at the interface between the two phases, and improve the purity of the hydrogen peroxide aqueous solution after extraction and the recovery rate of the extractant.

[0073] The preparation method of the solid hydrogenation catalyst comprises the following steps:

[0074] A1. Preparation of active seed solution: palladium nitrate solution and cobalt nitrate solution were mixed at a metal element ratio of 1:0.4 to obtain a mixed solution, wherein the total metal ion concentration in the mixed solution was 0.2 mol / L;

[0075] A2. Adjust the pH value of the mixed solution to 8-9, then add ethylenediaminetetraacetic acid (EDTA) in an amount 1.3 times the amount of the total metal ion substance, and stir at 50° C. for 40 minutes to obtain an active seed solution;

[0076] B1. Preparation of carrier core: γ-alumina powder with an average particle size of 8 μm was used as the core matrix, 8% sesbania powder was added, the mixture was evenly mixed, and deionized water was added to form a slurry. The slurry was granulated into particles with a diameter of 2 mm and dried at 110°C for 18 h to obtain a precursor body;

[0077] B2. Place the precursor body in a muffle furnace, heat it to 550°C at a heating rate of 5°C / min, keep it at this temperature for 4 hours, and then cool it to obtain the carrier core;

[0078] C1. Preparation of carrier shell: Tetraethyl orthosilicate, ethanol, and deionized water were mixed in a volume ratio of 1:1.5:3, and the pH value was adjusted to 2-3. The mixture was stirred for 40 minutes, and then polyvinyl pyrrolidone was added. The mixture was ultrasonically dispersed for 25 minutes to obtain a silica sol, in which the polyvinyl pyrrolidone accounted for 0.8% of the total mass.

[0079] C2, immersing the carrier core obtained in step B2 in silica sol for 50 minutes, taking it out and drying it at 90°C for 3 hours, repeating the immersion-drying process at least 3 times, and then calcining it at 350°C for 2 hours to obtain a core-shell structure carrier;

[0080] D1. Add the core-shell structure carrier obtained in step C2 to the active seed solution obtained in step A2, stir and immerse at 60° C. for 18 h, then wash the carrier to obtain a loaded intermediate;

[0081] D2, adding the loaded intermediate to hydrazine hydrate, and reducing it at a microwave power of 400 W for 40 min to obtain a catalyst precursor, wherein the amount of hydrazine hydrate added is 1.8 times the amount of the total metal ion substance in the loaded intermediate;

[0082] The catalyst precursor was placed in a tubular furnace, heated to 250°C at a heating rate of 10°C / min in a hydrogen atmosphere, kept for reduction for 2.5 hours, and then passed through nitrogen for passivation for 30 minutes after cooling to obtain a solid hydrogenation catalyst.

[0083] The solid hydrogenation catalyst of the present invention has a core-shell structure, wherein the core layer is wrapped by a porous silica shell layer, thereby suppressing the agglomeration or sintering of the core particles at high temperatures, and is suitable for high-temperature reactions in the calcination process and hydrogenation reaction.

[0084] At the same time, the shell can also prevent impurities in the reactants (such as sulfur and phosphorus) from directly contacting the core active sites, thereby extending the service life of the catalyst.

[0085] In addition, the low thermal conductivity of the SiO2 shell can effectively block the impact of the exothermic hydrogenation reaction on the core, reduce the temperature gradient inside the carrier, and inhibit the overheating decomposition of hydrogen peroxide on the catalyst surface.

[0086] A hydrogen peroxide production system based on efficient gas-liquid-solid circulating mixed flow reaction, such as Figure 1 As shown, it includes a working liquid preparation tank, a hydrogenation tower, an oxidation tower, an extraction tower and a purification tower, the output end of the working liquid preparation tank is connected to the liquid phase input end of the hydrogenation tower, the gas phase input end of the hydrogenation tower is connected to the output end of the hydrogen compressor, the solid phase input end of the hydrogenation tower is connected to the output end of the catalyst storage bin, the liquid phase output end of the hydrogenation tower is connected to the liquid phase input end of the oxidation tower, the gas phase input end of the oxidation tower is connected to the air compressor, the liquid phase output end of the oxidation tower is connected to the dispersed phase input end of the extraction tower, the continuous phase input end of the extraction tower is connected to the pure water supply end, and the hydrogen peroxide output end of the extraction tower is connected to the input end of the purification tower.

[0087] The hydrogenation tower is connected to hydrogen (gas phase), working fluid (liquid phase) and catalyst (solid phase) at the same time to form an efficient gas-liquid-solid mixed flow reaction system, which increases the contact area of the reactants, promotes mass transfer and heat transfer, and improves the hydrogenation reaction rate and conversion rate.

[0088] A regenerator is further provided between the working liquid preparation tank and the hydrogenation tower. The output of the working liquid preparation tank is connected to the liquid phase input of the regenerator, the output of the regenerator is connected to the liquid phase input of the hydrogenation tower, and the circulation output of the hydrogenation tower is connected to the circulation input of the regenerator. The regenerator realizes the circulation of the regenerated liquid.

[0089] 2. Performance Testing

[0090] The solid hydrogenation catalyst prepared in the present invention was tested.

[0091] Example 1

[0092] A1. Preparation of active seed solution: palladium nitrate solution and cobalt nitrate solution were mixed at a metal element ratio of 1:0.4 to obtain a mixed solution, wherein the total metal ion concentration in the mixed solution was 0.2 mol / L;

[0093] A2. Adjust the pH value of the mixed solution to 8, then add ethylenediaminetetraacetic acid (EDTA) in an amount 1.3 times the amount of the total metal ion substance, and stir at 50° C. for 40 minutes to obtain an active seed solution;

[0094] B1. Preparation of carrier core: γ-alumina powder with an average particle size of 8 μm was used as the core matrix, 8% sesbania powder was added, the mixture was evenly mixed, and deionized water was added to form a slurry. The slurry was granulated into particles with a diameter of 2 mm and dried at 110°C for 18 h to obtain a precursor body;

[0095] B2. Place the precursor body in a muffle furnace, heat it to 550°C at a heating rate of 5°C / min, keep it at this temperature for 4 hours, and then cool it to obtain the carrier core;

[0096] C1. Preparation of carrier shell: Tetraethyl orthosilicate, ethanol, and deionized water were mixed in a volume ratio of 1:1.5:3, and the pH value was adjusted to 2. The mixture was stirred for 40 minutes, and then polyvinyl pyrrolidone was added. The mixture was ultrasonically dispersed for 25 minutes to obtain a silica sol, in which the polyvinyl pyrrolidone accounted for 0.8% of the total mass.

[0097] C2, immersing the carrier core obtained in step B2 in silica sol for 50 minutes, taking it out and drying it at 90°C for 3 hours, repeating the immersion-drying process at least 3 times, and then calcining it at 350°C for 2 hours to obtain a core-shell structure carrier;

[0098] D1. Add the core-shell structure carrier obtained in step C2 to the active seed solution obtained in step A2, stir and immerse at 60° C. for 18 h, then wash the carrier to obtain a loaded intermediate;

[0099] D2, adding the loaded intermediate to hydrazine hydrate, and reducing it at a microwave power of 400 W for 40 min to obtain a catalyst precursor, wherein the amount of hydrazine hydrate added is 1.8 times the amount of the total metal ion substance in the loaded intermediate;

[0100] The catalyst precursor was placed in a tubular furnace, heated to 250°C at a heating rate of 10°C / min in a hydrogen atmosphere, kept for reduction for 2.5 hours, and then passed through nitrogen for passivation for 30 minutes after cooling to obtain a solid hydrogenation catalyst.

[0101] Example 2

[0102] A1. Preparation of active seed solution: A noble metal salt solution and a transition metal salt solution were mixed at a metal element ratio of 1:0.3 to obtain a mixed solution, wherein the total metal ion concentration in the mixed solution was 0.1 mol / L;

[0103] A2. The pH value of the mixed solution was adjusted to 8, and then ethylenediaminetetraacetic acid was added. The amount of ethylenediaminetetraacetic acid added was 1.2 times the amount of the total metal ion substance. The mixture was heated and stirred to obtain an active seed solution.

[0104] B1. Preparation of carrier core: γ-alumina powder was used as the core matrix, 5% sesbania powder was added, the mixture was evenly mixed, and water was added to form a slurry. The slurry was granulated into particles with a diameter of 1.5 mm, and dried to obtain a precursor body;

[0105] B2. Place the precursor body in a heating furnace and calcine it at 500°C for 3 hours. After cooling, obtain the carrier core;

[0106] C1. Preparation of carrier shell: Tetraethyl orthosilicate, ethanol, and deionized water were mixed in a volume ratio of 1:1:2, and then the pH value was adjusted to 3. The mixture was stirred evenly, and then polyvinyl pyrrolidone was added. After ultrasonic dispersion, a silica sol was obtained.

[0107] C2. Immerse the carrier core obtained in step B2 in silica sol for 40 minutes, take it out and dry it, and then calcine it at 300°C for 3 hours to obtain a core-shell structure carrier;

[0108] D1. Add the core-shell structured carrier obtained in step C2 to the active seed solution obtained in step A2 and immerse for 12 hours, then wash the carrier to obtain a loaded intermediate;

[0109] D2. The loaded intermediate was added to hydrazine hydrate to react and obtain a catalyst precursor. The catalyst precursor was placed in a tubular furnace and heated at 200° C. for 3 h under a hydrogen atmosphere. After cooling, nitrogen was introduced for passivation treatment for 20 min to obtain a solid hydrogenation catalyst.

[0110] Example 3

[0111] A1. Preparation of active seed solution: A noble metal salt solution and a transition metal salt solution were mixed at a metal element ratio of 1:0.5 to obtain a mixed solution, wherein the total metal ion concentration in the mixed solution was 0.3 mol / L;

[0112] A2. The pH value of the mixed solution was adjusted to 9, and then ethylenediaminetetraacetic acid was added, where the amount of ethylenediaminetetraacetic acid added was 1.5 times the amount of the total metal ion substance, and the mixture was heated and stirred to obtain an active seed solution;

[0113] B1. Preparation of carrier core: γ-alumina powder was used as the core matrix, 10% of sesbania powder was added, the mixture was evenly mixed, and water was added to form a slurry. The slurry was granulated into particles with a diameter of 2.5 mm, and dried to obtain a precursor body;

[0114] B2. Place the precursor body in a heating furnace and calcine it at 600°C for 5 hours. After cooling, obtain the carrier core;

[0115] C1. Preparation of carrier shell: Tetraethyl orthosilicate, ethanol, and deionized water were mixed in a volume ratio of 1:2:5, and the pH value was adjusted to 3. The mixture was stirred evenly, and polyvinyl pyrrolidone was added. The mixture was ultrasonically dispersed to obtain a silica sol.

[0116] C2. Immerse the carrier core obtained in step B2 in silica sol for 60 minutes, take it out and dry it, and then calcine it at 400°C for 2 hours to obtain a core-shell structure carrier;

[0117] D1. Add the core-shell structured carrier obtained in step C2 to the active seed solution obtained in step A2 and immerse for 24 hours, then wash the carrier to obtain a loaded intermediate;

[0118] D2. The loaded intermediate was added to hydrazine hydrate to react and obtain a catalyst precursor. The catalyst precursor was placed in a tubular furnace and heated at 300° C. for 2 h under a hydrogen atmosphere. After cooling, nitrogen was introduced for passivation treatment for 40 min to obtain a solid hydrogenation catalyst.

[0119] The solid hydrogenation catalysts prepared in Examples 1-3 and a commercially available solid hydrogenation catalyst (Comparative Example 1) were mixed with a working fluid and hydrogen, respectively, and then subjected to multiple hydrogenation reactions. The conversion rate of each hydrogenation reaction was tested. The test results are shown in Table 1.

[0120] Table 1

[0121] Example 1 Example 2 Example 3 Comparative Example 1 first 98.5 96.2 99.3 85.3 Second time 98.2 95.8 98.7 83.6 The third time 97.8 95.1 97.6 81.2 Fourth time 97.5 94.3 96.2 78.5 Fifth 97.1 93.5 95.0 75.6

Claims

1. A method for preparing hydrogen peroxide based on an efficient gas-liquid-solid circulating mixed flow reaction, characterized in that: The preparation method comprises the following steps: S1, 2-ethylanthraquinone and 2-amylanthraquinone in a mass ratio of 1-6:1 are mixed to form a solute, C10 heavy aromatic hydrocarbon and tetrabutyl urea in a mass ratio of 2-6:1 are mixed to form a solvent, and the solute and solvent are mixed in a mass ratio of 2.5:5.5:1 to form a working solution; S2, adding the working liquid, hydrogen and solid hydrogenation catalyst into a hydrogenation tower in three phases, mixing and performing a hydrogenation reaction to obtain a hydrogenated liquid containing anthrahydroquinone; S3, adding the hydrogenated liquid to the oxidation tower to react with oxygen to obtain an oxidation liquid containing hydrogen peroxide; S4, extracting the oxidizing liquid in an extraction tower to obtain a crude hydrogen peroxide product; S5. Purify and remove impurities from the crude hydrogen peroxide to obtain an industrial-grade hydrogen peroxide product.

2. The method for preparing hydrogen peroxide based on a high-efficiency gas-liquid-solid circulating mixed flow reaction according to claim 1, characterized in that: A gas phase distributor (1) is provided at the gas phase input end of the hydrogenation tower. The gas phase distributor (1) is in a disc-shaped structure. The gas phase input end of the hydrogenation tower is connected to the center of the gas phase distributor (1). The gas phase distributor (1) is provided with a plurality of diversion holes (2) in a ring-shaped array. The diameter of the diversion holes (2) increases step by step from the center of the gas phase distributor (1) to the peripheral side of the gas phase distributor (1).

3. The method for preparing hydrogen peroxide based on a high-efficiency gas-liquid-solid circulating mixed flow reaction according to claim 1, characterized in that: A plurality of groups of coolers (3) are arranged at intervals in the vertical direction in the oxidation tower. The liquid phase input end of the oxidation tower is arranged near the top of the oxidation tower. The liquid phase input end of the oxidation tower is provided with a plurality of rows of perforated tube-type liquid distributors (4).

4. The method for preparing hydrogen peroxide based on a high-efficiency gas-liquid-solid circulating mixed flow reaction according to claim 1, characterized in that: A coalescer (5) is provided in the extraction tower, and the packing layer of the coalescer (5) comprises a highly hydrophilic coalescing packing layer (6) and a highly hydrophobic coalescing packing layer (7).

5. The method for preparing hydrogen peroxide based on a high-efficiency gas-liquid-solid circulating mixed flow reaction according to claim 1, characterized in that: The preparation method of the solid hydrogenation catalyst comprises the following steps: A1. Preparation of active seed solution: A noble metal salt solution and a transition metal salt solution are mixed at a metal element ratio of 1:0.3-0.5 to obtain a mixed solution, wherein the total metal ion concentration in the mixed solution is 0.1-0.3 mol / L; A2. Adjust the pH value of the mixed solution to 8-9, then add ethylenediaminetetraacetic acid (EDTA) in an amount of 1.2-1.5 times the amount of the total metal ion substance, and heat and stir to obtain an active seed solution; B1. Preparation of carrier core: γ-alumina powder is used as the core matrix, 5%-10% of sesbania powder is added, the mixture is evenly mixed, and water is added to form a slurry. The slurry is granulated into particles with a diameter of 1.5-2.5 mm, and dried to obtain a precursor body; B2. Place the precursor body in a heating furnace and calcine it at a temperature of 500-600°C for 3-5 hours. After cooling, obtain the carrier core; C1. Preparation of carrier shell: Tetraethyl orthosilicate, ethanol, and deionized water were mixed in a volume ratio of 1:1-2:2-5, and the pH value was adjusted to 2-3. The mixture was stirred evenly, and polyvinyl pyrrolidone was added. The silica sol was obtained by ultrasonic dispersion. C2. Immerse the core of the carrier obtained in step B2 in silica sol for 40-60 minutes, remove it and dry it, and then calcine it at 300-400°C for 2-3 hours to obtain a core-shell structure carrier; D1. Add the core-shell structured carrier obtained in step C2 to the active seed solution obtained in step A2 and immerse for 12-24 hours, then wash the carrier to obtain a loaded intermediate; D2. Add the loaded intermediate to hydrazine hydrate to react and obtain a catalyst precursor. Place the catalyst precursor in a tubular furnace and heat it at 200-300° C. for 2-3 hours under a hydrogen atmosphere. After cooling, introduce nitrogen for passivation treatment for 20-40 minutes to obtain a solid hydrogenation catalyst.

6. The method for preparing hydrogen peroxide based on a high-efficiency gas-liquid-solid circulating mixed flow reaction according to claim 5, characterized in that: The amount of hydrazine hydrate added in step D2 is 1.5-2 times the amount of the total metal ion substance in the loaded intermediate.

7. A hydrogen peroxide production system based on a high-efficiency gas-liquid-solid circulating mixed flow reaction, used in the hydrogen peroxide preparation method based on a high-efficiency gas-liquid-solid circulating mixed flow reaction as described in claim 1, characterized in that: The invention comprises a working liquid preparation tank, a hydrogenation tower, an oxidation tower, an extraction tower and a purification tower. The output end of the working liquid preparation tank is connected to the liquid phase input end of the hydrogenation tower, the gas phase input end of the hydrogenation tower is connected to the output end of the hydrogen compressor, the solid phase input end of the hydrogenation tower is connected to the output end of the catalyst storage bin, the liquid phase output end of the hydrogenation tower is connected to the liquid phase input end of the oxidation tower, the gas phase input end of the oxidation tower is connected to the air compressor, the liquid phase output end of the oxidation tower is connected to the dispersed phase input end of the extraction tower, the continuous phase input end of the extraction tower is connected to the pure water supply end, and the hydrogen peroxide output end of the extraction tower is connected to the input end of the purification tower.

8. A hydrogen peroxide production system based on a high-efficiency gas-liquid-solid circulating mixed flow reaction according to claim 7, characterized in that: A regenerator is further provided between the working liquid preparation tank and the hydrogenation tower. The output end of the working liquid preparation tank is connected to the liquid phase input end of the regenerator, the output end of the regenerator is connected to the liquid phase input end of the hydrogenation tower, and the circulation output end of the hydrogenation tower is connected to the circulation input end of the regenerator.

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