Hydrogenation reactor and hydrogenation method for producing hydrogen peroxide by anthraquinone process

Abstract

The invention provides a hydrogenation reactor and a hydrogenation method for producing hydrogen peroxide by an anthraquinone process, the reactor comprises an outer cylinder and at least one inner cylinder, the inner cylinder is filled with catalyst particles, an anthraquinone working solution enters the reactor through a liquid feed inlet at the top of the inner cylinder, hydrogen enters the inner cylinder through a gas distribution disc from a gas inlet at the bottom, and the catalyst particles are fed into the inner cylinder. Catalyst particles flow in the inner cylinder in a fluidized state under the driving of gas, hydrogen and the working solution are subjected to a catalytic reaction in the inner cylinder, the gas is discharged from an exhaust port in the top, the reacted working solution is baffled at the bottom of the inner cylinder and then enters the space between the inner cylinder and the outer cylinder, and precipitation separation of the catalyst is carried out; and the working liquid is discharged from a liquid discharge hole in the upper part, namely the hydrogenated liquid. According to the invention, a form similar to a boiling bed is realized, uniform mixing of reaction materials and a catalyst is facilitated, mass and heat transfer effects in a system are good, side reactions are few, product quality is high, and the problem of hot spots generated in the production process of a fixed bed hydrogenation reactor can be well solved.

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] The production methods of hydrogen peroxide include anthraquinone method, isopropanol method, electrolysis method, oxygen cathode reduction method, oxygen and water synthesis method and direct hydrogen and oxygen synthesis method. The anthraquinone method is widely used in the industrial production of hydrogen peroxide due to its comprehensive advantages in industrial efficiency, environmental protection and economy. The technology of producing hydrogen peroxide by anthraquinone method is based on the catalytic hydrogenation of anthraquinone to generate hydroanthraquinone, which is then oxidized to generate hydrogen peroxide. This process includes two main steps: hydrogenation and oxidation. The efficiency of hydrogenation directly determines the output and concentration of hydrogen peroxide and is an important link in the production of hydrogen peroxide. At present, the anthraquinone hydrogenation process in China mainly includes fixed bed process and fluidized bed process. The fixed bed process is relatively mature, but the hydrogenation rate is low, the mass transfer and heat transfer are poor, and local hydrogenation is prone to produce hot spots. The fluidized bed process has good mass transfer and heat transfer, high hydrogenation rate, easy replacement of catalysts, suitable for large-scale production, and has received widespread attention from the industry.

[0003] Patent US3423176A discloses a tubular suspended bed reactor for producing hydrogen peroxide by anthraquinone method. The reactor is composed of horizontal and vertical reaction tubes connected by elbows. A slit channel is formed in the reaction tube. After hydrogen and materials containing catalysts are premixed in a venturi mixer, they enter the slit channel from the bottom of the reaction tube for suspended hydrogenation. Patent CN104549059A discloses a slurry bed reactor for producing hydrogen peroxide by anthraquinone method and its application. A slurry bed reactor with an expanded upper diameter is adopted. 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 of 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] In order to solve the deficiencies in the prior art, the present invention provides a hydrogenation reactor and method for producing hydrogen peroxide by anthraquinone method, wherein the catalyst can be separated in the reactor, which greatly reduces the pressure of the subsequent filtering device and reduces the filtration loss of the catalyst. The reactor can unload and add the agent online, and has good mass and heat transfer performance, improves the hydrogenation efficiency, and the device can achieve 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 an anthraquinone process, comprising an outer cylinder and at least one inner cylinder arranged in the outer cylinder, the inner cylinder and the outer cylinder are connected at the bottom, and the tops are sealed together, a gas distribution plate is provided at the bottom of the inner cylinder, and the gas distribution plate is connected to a gas inlet; at least one exhaust port is 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 are also provided at the top of the inner cylinder, a solid discharge port is provided at the bottom of the outer cylinder, and a liquid discharge port is provided at the top of the outer cylinder.

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

[0008] Furthermore, the ratio of the distance from the baffle plate 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 baffle plate to the inner wall of the outer cylinder to the height of the baffle plate 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 part of the reaction zone of the inner cylinder to prevent the solids in the inner cylinder from entering the upper outlet. Preferably, the baffle is an inverted V-shaped baffle.

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

[0014] The technical purpose of the second aspect of the present invention is to provide a hydrogenation method for producing hydrogen peroxide by anthraquinone method, using the above-mentioned reactor, filling catalyst particles in an inner cylinder, anthraquinone working liquid enters the reactor through the liquid feed port at the top of the inner cylinder, hydrogen enters the inner cylinder through the gas inlet at the bottom through the gas distribution plate, and the catalyst particles flow in the inner cylinder in a fluidized state under the drive of the gas, and the hydrogen and the working liquid undergo a catalytic reaction in the inner cylinder, and the gas is discharged from the exhaust port at the top. The working liquid after the reaction enters between the inner cylinder and the outer cylinder after being deflected at the bottom of the inner cylinder, and precipitation and separation of the catalyst occur, and the working liquid is discharged from the liquid discharge port at the top, which is the hydrogenation 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 that can achieve anthraquinone hydrogenation reaction in the prior art, and the average particle size of the particles is 0.01mm-3.0mm, preferably 0.1mm-1.5mm, and most preferably 0.3mm-1.0mm. Specifically, the above catalyst is generally a catalyst with an inorganic refractory oxide as a carrier and a Group VIII metal loaded thereon.

[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 tube of the reactor is 30-80°C, preferably 40-60°C, and the pressure in the inner tube 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 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 needs to 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 inlet 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 the 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: (1) The hydrogenation reactor of the present invention realizes a form similar to that of an ebullating 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.

[0022] (2) The reactor of the present invention adopts the method of top liquid feeding, bottom deflection and then liquid discharge, 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 of subsequent filters.

[0023] (3) The hydrogenation reactor of the present invention can realize online replacement of the catalyst, thereby extending the operation cycle of the device.

[0024] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the hydrogenation reactor device of the present invention. DETAILED DESCRIPTION

[0026] The following non-limiting embodiments may enable a person 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

[0027] 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 arranged in the outer cylinder, the inner cylinder 1 and the outer cylinder 2 are connected at the bottom and sealed at the top, the bottom of the inner cylinder 1 is provided with a gas distribution plate 3, and the gas distribution plate 3 is connected to the gas inlet 4; the top of the inner cylinder 1 and the top of the inner cylinder 1 are provided with an exhaust port Ⅰ103, the top between the inner cylinder 1 and the outer cylinder 2 is provided with an exhaust port Ⅱ201 and an exhaust port Ⅲ202, 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 Ⅰ231 and a solid discharge port Ⅱ232, the upper part of the outer cylinder 2 is provided with a liquid discharge port Ⅰ211 and a liquid discharge port Ⅱ212, the front section thereof is provided with a baffle plate Ⅰ221 and a baffle plate Ⅱ222, and the rear end thereof is connected with a filter Ⅰ241 and a filter Ⅱ242, respectively. The distance from the baffle plate to 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. An inverted V-shaped baffle 5 with holes is fixed on the upper part of the inner cylinder 1. The baffle 5 has small holes, and the diameter of the small holes is smaller than the diameter of the catalyst particles. The bottom of the inner cylinder 1 is provided with an outward trumpet-shaped baffle. The angle between the trumpet-shaped baffle and the horizontal plane is 60°. The ratio of the length of the trumpet-shaped baffle to the distance from the inner wall of the outer cylinder to the outer wall of the inner cylinder 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 diameter of the inner cylinder 1 is 8 cm, and the distance from the inner wall of the outer cylinder to the outer wall of the inner cylinder is 2 cm. The ratio of the height of the bottom end of the inner cylinder from the bottom end of the outer cylinder to the diameter of the inner cylinder is 1:4.

[0028] Method for hydrogenating anthraquinone using the above hydrogenation reactor: Catalyst particles 6 are filled in the inner tube 1, 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, and the catalyst particles 6 flow in the inner tube 1 in a fluidized state driven by the gas, and the hydrogen and the working liquid undergo a catalytic reaction in the inner tube 1, and the gas is discharged from the exhaust port Ⅰ103 at the top. The working liquid after the reaction enters between the inner tube 1 and the outer tube 2 after being deflected at the bottom of the inner tube 1, and 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 upper liquid discharge port Ⅰ211 and the liquid discharge port Ⅱ212, and is filtered by the filter Ⅰ241 and the filter Ⅱ242 to obtain the hydrogenated liquid, and the excess gas is discharged from the exhaust port Ⅱ201 and the exhaust port Ⅲ202.

[0029] 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 driven by the intake air. When the catalyst needs to be replaced, the solid discharge port I231 and the solid discharge port II232 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.

[0030] The hydrogenated liquid produced by the reaction is filtered at multiple stages and then enters the oxidation reactor of the oxidation unit to react with oxygen to obtain an oxidized liquid containing hydrogen peroxide. The oxidized liquid is extracted and separated in the extraction device to obtain the product hydrogen peroxide and anthraquinone working liquid. The extracted working liquid is dried and purified before being recycled.

[0031] The working solution used in the following examples is: 2-ethylanthraquinone and a solvent are mixed in a volume ratio of 1:1, and the solvent is a heavy aromatic hydrocarbon and tetrabutyl urea, which are mixed in a volume ratio of 3:1.

[0032] 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

[0033] The catalyst particles were loaded at 30% of the total volume of the inner cylinder, the reaction temperature of the inner cylinder of the hydrogenation reactor was 50°C, the reaction pressure in the inner cylinder was 0.2 MPa, and the working liquid feed rate was 0.12 m 3 / h, the total hydrogen feed is 0.48Nm 3 / h.

[0034] The liquid after the reaction is first filtered through filter I 241 and filter II 242, and backwashing is performed when the filter pressure difference is set to be greater than 0.1Mpa. The hydrogenated liquid after filtration is then subjected to secondary filtration to make its solid content less than 5ppm. The filtered hydrogenated liquid enters the oxidation reactor, the reaction temperature is 50°C, the pressure is 0.2MPa, and the oxidized product enters the extraction tower, at 55°C, the pure water flow rate is 1.2m 3 / h for extraction treatment. After the reaction stabilized, the hydrogen efficiency of the reaction was 13gH2O2 / L.

[0035] The interior of the reactor is completely fluidized and in a fully mixed state. The system is uniform and has good mass and heat transfer effects, effectively preventing the appearance of hot spots. The catalyst in the outer cylinder has a long precipitation time, good separation effect, and reduces the subsequent filtration pressure.

[0036] During the above reaction process, the catalyst is replaced at a rate of 100% per year through online unloading and adding. The above reactor can operate stably for a long period of time to achieve continuous production.

Claims

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

2. The hydrogenation reactor according to claim 1, characterized in that A baffle plate is also arranged at the front end of the liquid outlet, so that the liquid material can be discharged from the liquid outlet after passing through the baffle plate.

3. The hydrogenation reactor according to claim 2, characterized in that The ratio of the distance from the baffle plate 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 baffle plate to the inner wall of the outer cylinder to the height of the baffle plate 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 arranged 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 arranged 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, 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, hydrogen enters the inner cylinder through a gas distribution plate from a gas inlet at the bottom, catalyst particles flow in a fluidized state in the inner cylinder driven by the gas, hydrogen and working liquid undergo a catalytic reaction in the inner cylinder, gas is discharged from an exhaust port at the top, 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, and precipitation and separation of the catalyst occurs, and the working liquid is discharged from a liquid discharge port at the top, i.e., hydrogenated liquid.

9. The hydrogenation method according to claim 8, characterized in that The loading amount of 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-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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