A hydrogenation reactor and hydrogenation method for producing hydrogen peroxide by anthraquinone method

Abstract

The present invention provides a hydrogenation reactor and hydrogenation method for producing hydrogen peroxide using the anthraquinone process. The reactor comprises an outer cylinder and at least one inner cylinder. Catalyst particles are loaded into the inner cylinder. Anthraquinone working liquid enters the reactor through a liquid feed port at the top of the inner cylinder. Hydrogen enters the inner cylinder through a gas distribution plate at the bottom gas inlet. Driven by the gas, the catalyst particles flow in a fluidized state within the inner cylinder. The hydrogen and working liquid undergo a catalytic reaction within the inner cylinder. The gas is discharged through an exhaust port at the top. The reacted working liquid is deflected at the bottom of the inner cylinder and then flows between the inner and outer cylinders, where precipitation and separation of the catalyst occur. The working liquid is discharged through a liquid discharge port at the top to form a hydrogenated liquid. The present invention achieves a fluidized bed-like structure, which facilitates uniform mixing of the reactants and the catalyst. The system has good mass and heat transfer effects, minimizes side reactions, and achieves high product quality. This effectively addresses the hotspot problem that occurs during the production process of fixed-bed hydrogenation reactors.

Description

Technical Field

[0001] The present invention relates to a hydrogenation reactor, in particular to a hydrogenation reactor for producing hydrogen peroxide from anthraquinone, and a method for hydrogenating anthraquinone using the reactor. Background Art

[0002] Methods for producing hydrogen peroxide include the anthraquinone method, the isopropanol method, electrolysis, oxygen cathode reduction, oxygen-water synthesis, and direct hydrogen-oxygen synthesis. The anthraquinone method is widely used for the industrial production of hydrogen peroxide due to its combined advantages in industrial efficiency, environmental friendliness, and cost-effectiveness. The anthraquinone method for producing hydrogen peroxide is based on the catalytic hydrogenation of anthraquinone to produce hydroanthraquinone, which is then oxidized to produce hydrogen peroxide. This process consists of two main steps: hydrogenation and oxidation. The efficiency of hydrogenation directly determines the yield and concentration of hydrogen peroxide, making it a critical step in the production process. Currently, the main anthraquinone hydrogenation processes include fixed-bed and fluidized-bed processes. The fixed-bed process is relatively mature, but it suffers from low hydrogenation rates, poor mass and heat transfer, and the tendency for localized hydrogenation to generate hot spots. In contrast, the fluidized-bed process offers superior mass and heat transfer, high hydrogenation rates, and easily replaceable catalysts, making it suitable for large-scale production and attracting widespread attention in the industry.

[0003] Patent US3423176A discloses a tubular suspended bed reactor for producing hydrogen peroxide by an anthraquinone process. The reactor consists of horizontal and vertical reaction tubes connected by elbows. A slit channel is formed in the reaction tube. After premixing hydrogen and a material containing a catalyst in a venturi mixer, the mixture enters the slit channel from the bottom of the reaction tube for suspension hydrogenation. Patent CN104549059A discloses a slurry bed reactor for producing hydrogen peroxide by an anthraquinone process and its application. The reactor adopts a slurry bed reactor with an expanded upper diameter. The reaction effluent is filtered through a post-filter, the filtrate is discharged, and the catalyst is recycled. The fluidized bed reactor can fully mix the catalyst with the working fluid and has good mass and heat transfer performance, but the catalyst separation is difficult, and a filtering device needs to be added later, which greatly increases the burden on the filtering equipment.

[0004] The reactor design that realizes online separation of catalysts and maintains good mass and heat transfer performance will greatly reduce the pressure of subsequent filtration, extend the operating cycle, and improve the stability of the reaction. Summary of the Invention

[0005] To address the shortcomings of the existing technology, the present invention provides a hydrogenation reactor and method for producing hydrogen peroxide using the anthraquinone process. The catalyst can be separated within the reactor, significantly reducing pressure in subsequent filtration equipment and minimizing catalyst filtration losses. The reactor allows for online catalyst unloading and addition, and exhibits excellent mass and heat transfer performance, improving hydrogenation efficiency and enabling long-term stable operation.

[0006] To achieve the above technical objectives, the first aspect of the present invention provides a hydrogenation reactor for producing hydrogen peroxide by the anthraquinone process, comprising an outer cylinder and at least one inner cylinder arranged within the outer cylinder, the inner cylinder and the outer cylinder being connected at the bottom and sealed at the top, a gas distribution plate being provided at the bottom of the inner cylinder, the gas distribution plate being connected to a gas inlet, at least one exhaust port being provided at the top of the inner cylinder and at the top between the inner cylinder and the outer cylinder, a solid feed port and a liquid feed port being further provided at the top of the inner cylinder, a solid discharge port being provided at the bottom of the outer cylinder, and a liquid discharge port being provided at the top of the outer cylinder.

[0007] Furthermore, a deflection baffle is provided at the front end of the liquid outlet so that the liquid material passes through the deflection baffle and is discharged from the liquid outlet.

[0008] Furthermore, the ratio of the distance from the deflection baffle to the inner wall of the outer cylinder to the distance from the outer wall of the inner cylinder to the inner wall of the outer cylinder is 1:1.5-10, preferably 1:2-4.5, and the ratio of the distance from the deflection baffle to the inner wall of the outer cylinder to the height of the deflection baffle is 1:2-15, preferably 1:3-8.

[0009] Furthermore, the liquid outlet is also connected to a filtering device.

[0010] Furthermore, the ratio of the distance between the bottom end of the inner cylinder and the bottom end of the outer cylinder to the diameter of the inner cylinder is 1:0.5-10, preferably 1:2-8.

[0011] Furthermore, an outward trumpet-shaped baffle is provided at the bottom of the inner cylinder, the angle between the trumpet-shaped baffle and the horizontal plane is 10°-80°, preferably 25°-70°, and the ratio of the baffle length to the distance between the outer cylinder and the inner cylinder is 1:1.5-8, preferably 1:2-4.

[0012] Furthermore, a baffle with holes is provided on the upper portion of the reaction zone of the inner tube to prevent solids in the inner tube from entering the upper outlet. Preferably, the baffle is an inverted V-shaped baffle.

[0013] Furthermore, the ratio of the outer cylinder diameter to the reactor height of the hydrogenation reactor is 1:1-30, preferably 1:3-12; the ratio of the cross-sectional area of ​​the outer cylinder to the sum of the cross-sectional areas of the inner cylinder is 100:20-90, preferably 100:30-70.

[0014] The second aspect of the present invention is to provide a hydrogenation method for producing hydrogen peroxide using the anthraquinone process. The method comprises the following steps: using the above-mentioned reactor, filling an inner cylinder with catalyst particles, and allowing an anthraquinone working liquid to enter the reactor through a liquid feed port at the top of the inner cylinder. Hydrogen enters the inner cylinder from a gas inlet at the bottom through a gas distribution plate. Driven by the gas, the catalyst particles flow in a fluidized state within the inner cylinder. The hydrogen and working liquid undergo a catalytic reaction within the inner cylinder, and the gas is discharged from an exhaust port at the top. The reacted working liquid is then deflected at the bottom of the inner cylinder and flows between the inner and outer cylinders, where precipitation and separation of the catalyst occur. The working liquid is then discharged from a liquid discharge port at the top to form a hydrogenated liquid.

[0015] Furthermore, based on the total volume of the inner cylinder, the loading amount of the catalyst particles is 15%-40%, preferably 25%-35%.

[0016] Furthermore, the catalyst used in the above method is a catalyst known in the art capable of achieving anthraquinone hydrogenation, and has an average particle size of 0.01 mm to 3.0 mm, preferably 0.1 mm to 1.5 mm, and most preferably 0.3 mm to 1.0 mm. Specifically, the above catalyst is generally a Group VIII metal supported on an inorganic refractory oxide.

[0017] Furthermore, in the above method, the catalyst can be replaced online through the solid feed port at the top and the solid discharge port at the bottom.

[0018] Furthermore, in the above method, the reaction temperature of the inner barrel of the reactor is 30-80°C, preferably 40-60°C, and the pressure in the inner barrel is 0.15-0.55 MPa, preferably 0.2-0.3 MPa.

[0019] Furthermore, the hydrogenated liquid obtained by the reaction is filtered and then enters the subsequent oxidation unit and extraction and separation unit to obtain the product hydrogen peroxide and anthraquinone working solution. It should be understood by those skilled in the art that the hydrogenated liquid must be finely filtered multiple times before entering the oxidation unit to ensure that the amount of catalyst residue in the hydrogenated liquid meets the liquid feed requirements of the oxidation reaction before entering the oxidation unit.

[0020] Furthermore, the anthraquinone working solution is prepared by dissolving alkyl anthraquinone in an organic solvent, and a solvent system disclosed in the prior art can be used, such as anthraquinone derivatives, heavy aromatics (C10), trioctyl phosphate, etc.

[0021] The technical solution of the present invention has the following advantages:

[0022] (1) The hydrogenation reactor of this invention realizes a form similar to that of an ebullient bed, which is conducive to the uniform mixing of the reaction materials and the catalyst, has good mass and heat transfer effects in the system, has few side reactions, and has high product quality. It can effectively solve the hot spot problem generated during the production process of a fixed-bed hydrogenation reactor.

[0023] (2) The reactor of the present invention adopts the method of feeding liquid from the top, deflecting the liquid at the bottom and then discharging the liquid, so that the catalyst is precipitated and separated from the reaction liquid at the bottom of the reactor, and the reaction liquid is discharged from the upper part of the reactor. The solid-liquid separation effect is good, which greatly reduces the burden on subsequent filters.

[0024] (3) The hydrogenation reactor of the present invention can realize online replacement of the catalyst, thereby extending the operating cycle of the device.

[0025] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the hydrogenation reactor device of the present invention. DETAILED DESCRIPTION

[0027] The following non-limiting examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way. Example 1

[0028] This embodiment provides a hydrogenation reactor for producing hydrogen peroxide by anthraquinone method, such as Figure 1 As shown, it includes an outer cylinder 2 and at least one inner cylinder 1 disposed within the outer cylinder. The inner cylinder 1 and outer cylinder 2 are connected at the bottom and sealed at the top. A gas distribution plate 3 is provided at the bottom of the inner cylinder 1, which is connected to a gas inlet 4. Exhaust port I 103 is provided at the top of the inner cylinder 1, and exhaust ports II 201 and III 202 are provided at the top between the inner cylinder 1 and the outer cylinder 2. The top of the inner cylinder 2 is also provided with a solid feed port 102 and a liquid feed port 101. The bottom of the outer cylinder is provided with a solid discharge port I 231 and a solid discharge port II 232. The upper portion of the outer cylinder 2 is provided with a liquid discharge port I 211 and a liquid discharge port II 212. The front ends of the outer cylinders are provided with a baffle I 221 and a baffle II 222, respectively, and the rear ends are connected to a filter I 241 and a filter II 242, respectively. The distance between the baffle and the inner wall of the outer cylinder is 1 cm, and the height is 5 cm. The inner cylinder 1 is filled with catalyst particles 6. A perforated inverted V-shaped baffle 5 with small holes smaller than the diameter of the catalyst particles is fixed to the top of the inner cylinder 1. An outward-facing trumpet-shaped baffle is installed at the bottom of the inner cylinder 1. The trumpet-shaped baffle is angled 60° with the horizontal plane, and the ratio of the trumpet-shaped baffle length to the distance from the inner wall of the outer cylinder to the outer wall is 1:2.5. The outer cylinder 2 of the hydrogenation reactor has a diameter of 12 cm and a height of 70 cm. The inner cylinder 1 has a diameter of 8 cm, and the distance from the inner wall of the outer cylinder to the outer wall is 2 cm. The ratio of the height of the bottom of the inner cylinder to the diameter of the inner cylinder is 1:4.

[0029] Method for hydrogenating anthraquinone using the above hydrogenation reactor:

[0030] Catalyst particles 6 are filled in the inner tube 1, and the anthraquinone working liquid enters the reactor through the liquid feed port 101 at the top of the inner tube. Hydrogen enters the inner tube 1 through the gas distribution plate 3 from the gas inlet 4 at the bottom. Driven by the gas, the catalyst particles 6 flow in the inner tube 1 in a fluidized state. The hydrogen and the working liquid undergo a catalytic reaction in the inner tube 1, and the gas is discharged from the exhaust port I 103 at the top. The working liquid after the reaction is deflected at the bottom of the inner tube 1 and enters between the inner tube 1 and the outer tube 2, where the catalyst particles 6 are precipitated and separated. Under the action of the trumpet-shaped baffle, the precipitation is more complete, and the catalyst particles 6 will continue to precipitate during the rising process of the liquid. The working liquid is discharged from the liquid discharge port I 211 and the liquid discharge port II 212 at the top, filtered by the filter I 241 and the filter II 242, and is the hydrogenated liquid. The excess gas is discharged from the exhaust port II 201 and the exhaust port III 202.

[0031] During the above reaction process, the catalyst particles 6 settle and flow back to the bottom of the outer tube 2, and participate in the reaction again under the drive of the intake air. When the catalyst needs to be replaced, the solid discharge port I 231 and the solid discharge port II 232 are opened to allow the catalyst to flow out at a certain flow rate for online unloading, and online addition is performed through the solid feed port 102 above the inner tube 1.

[0032] The resulting hydrogenated liquid undergoes multi-stage filtration before entering the oxidation reactor of the oxidation unit, where it reacts with oxygen to produce an oxidized liquid containing hydrogen peroxide. This oxidized liquid is then extracted and separated in an extraction unit to produce the product hydrogen peroxide and anthraquinone working solution. The extracted working solution is then dried, purified, and recycled.

[0033] The working solution used in the following examples is: 2-ethylanthraquinone and a solvent mixed in a volume ratio of 1:1, and the solvent is a heavy aromatic hydrocarbon and tetrabutyl urea mixed in a volume ratio of 3:1.

[0034] The catalyst is a supported catalyst of palladium on alumina, with a palladium loading of 5%. The carrier is spherical alumina with an average particle size of 0.5 mm and a specific surface area of ​​more than 800 m 2 / g. Example 2

[0035] The filling amount of catalyst particles is 30% based on the total volume of the inner cylinder, the reaction temperature of the inner cylinder of the hydrogenation reactor is 50℃, the reaction pressure in the inner cylinder is 0.2Mpa, and the working liquid feed amount is 0.12m 3 / h, the total hydrogen feed rate is 0.48Nm 3 / h.

[0036] The liquid after the reaction is first filtered through filter I 241 and filter II 242, and backwash is performed when the filter pressure difference is set to be greater than 0.1 MPa. The hydrogenated liquid after filtration is then subjected to secondary filtration to reduce its solid content to less than 5 ppm. The filtered hydrogenated liquid enters the oxidation reactor at a reaction temperature of 50°C and a pressure of 0.2 MPa. The oxidized product enters the extraction tower at a temperature of 55°C and a pure water flow rate of 1.2 m 3 After the reaction stabilized, the hydrogen efficiency was 13 gH2O2 / L.

[0037] The interior of the reactor is fully fluidized and in a fully mixed state. The system is homogeneous, with good mass and heat transfer effects, effectively preventing the occurrence of hot spots. The catalyst sedimentation time in the outer cylinder is long, the separation effect is good, and the subsequent filtration pressure is reduced.

[0038] During the above reaction process, the catalyst is replaced through online unloading and adding at a rate of 100% per year. The above reactor can operate stably for a long period of time and realize continuous production.

Claims

1. A hydrogenation reactor for producing hydrogen peroxide by anthraquinone process, characterized in that: It includes an outer tube and at least one inner tube arranged in the outer tube. The inner tube and the outer tube are connected at the bottom and sealed at the top. A gas distribution plate is provided at the bottom of the inner tube, and the gas distribution plate is connected to the gas inlet. At least one exhaust port is provided at the top of the inner tube and the top between the inner tube and the outer tube. A solid feed port and a liquid feed port are also provided at the top of the inner tube. A solid discharge port is provided at the bottom of the outer tube, and a liquid discharge port is provided at the top of the outer tube.

2. The hydrogenation reactor according to claim 1, characterized in that A deflection baffle is also provided at the front end of the liquid discharge port, so that the liquid material passes through the deflection baffle and is discharged from the liquid discharge port.

3. The hydrogenation reactor according to claim 2, characterized in that The ratio of the distance from the deflection baffle to the inner wall of the outer cylinder to the distance from the outer wall of the inner cylinder to the inner wall of the outer cylinder is 1:1.5-10, and the ratio of the distance from the deflection baffle to the inner wall of the outer cylinder to the height of the deflection baffle is 1:2-15.

4. The hydrogenation reactor according to claim 1, characterized in that The ratio of the distance between the bottom end of the inner cylinder and the bottom end of the outer cylinder to the diameter of the inner cylinder is 1:0.5-10.

5. The hydrogenation reactor according to claim 1, characterized in that An outward trumpet-shaped baffle is provided at the bottom of the inner cylinder. The angle between the trumpet-shaped baffle and the horizontal plane is 10°-80°, and the ratio of the baffle length to the distance between the outer cylinder and the inner cylinder is 1:1.5-8.

6. The hydrogenation reactor according to claim 1, characterized in that A baffle with holes is provided on the upper part of the reaction zone of the inner cylinder.

7. The hydrogenation reactor according to claim 1, characterized in that The ratio of the outer cylinder diameter to the reactor height is 1:1-30, and the ratio of the cross-sectional area of ​​the outer cylinder to the sum of the cross-sectional areas of the inner cylinder is 100:20-90.

8. A hydrogenation method for producing hydrogen peroxide by anthraquinone method, characterized in that: A hydrogenation reactor according to any one of claims 1 to 7 is used, wherein catalyst particles are filled in an inner cylinder, anthraquinone working liquid enters the reactor through a liquid feed port at the top of the inner cylinder, and hydrogen enters the inner cylinder through a gas distribution plate from a gas inlet at the bottom. Driven by the gas, the catalyst particles flow in the inner cylinder in a fluidized state, and the hydrogen and working liquid undergo a catalytic reaction in the inner cylinder. The gas is discharged from the exhaust port at the top, and the working liquid after the reaction is deflected at the bottom of the inner cylinder and enters between the inner cylinder and the outer cylinder, where precipitation and separation of the catalyst occur. The working liquid is discharged from the liquid discharge port at the top to obtain the hydrogenated liquid.

9. The hydrogenation method according to claim 8, characterized in that The filling amount of the catalyst particles is 15%-40% based on the total volume of the inner cylinder.

10. The hydrogenation method according to claim 8, characterized in that The average particle size of the catalyst particles is 0.01 mm to 3.0 mm.

11. The hydrogenation method according to claim 8, characterized in that The catalyst is replaced online through the solid feed port at the top and the solid discharge port at the bottom.

12. The hydrogenation method according to claim 8, characterized in that The reaction temperature of the inner tube of the reactor is 30-80°C, and the pressure inside the inner tube is 0.15-0.55Mpa.

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