Liquid-phase hydrogenation reaction equipment and application thereof, and method for preparing CBDO by hydrogenation of TMCB

Abstract

The invention relates to the field of liquid-phase hydrogenation, and discloses liquid-phase hydrogenation reaction equipment and application thereof and a method for preparing CBDO through TMCB hydrogenation, and the liquid-phase hydrogenation reaction equipment comprises a gas-liquid mixing unit, a bubble breaking unit and a reaction unit which are communicated in sequence, so that hydrogen and a liquid-phase material are mixed and subjected to bubble breaking, and then are fed into the reaction unit for hydrogenation reaction; wherein the arrangement of the reaction unit can prevent the hydrogenation catalyst from being broken. The method has the advantages of reducing the influence of mass transfer in the reaction process and improving the hydrogenation reaction efficiency.

Description

Technical Field

[0001] The present invention relates to the field of liquid-phase hydrogenation, and particularly to a liquid-phase hydrogenation reaction device and its application, and a method for preparing CBDO by hydrogenating TMCB. Background Art

[0002] In the petroleum refining industry, the hydrogenation process is widely used not only for hydrocracking but also for hydrorefining to remove oxygen, sulfur, nitrogen and other impurities present in oil products, and to fully saturate olefins and partially saturate aromatics to improve the quality of oil products. In coal chemical industry, it is used for coal hydrogenation liquefaction to produce liquid fuels. In organic chemical industry, it is used to prepare various organic products, such as synthesis of methanol by hydrogenation of carbon monoxide, production of cyclohexane by hydrogenation of benzene, production of cyclohexanol by hydrogenation of phenol, production of alcohol by hydrogenation of aldehyde, production of tetrahydronaphthalene and decahydronaphthalene (used as solvents) by hydrogenation of naphthalene, reduction of nitrobenzene to aniline by hydrogenation, etc. The commonly used hydrogenation reactors in industry are fixed beds, trickle beds or stirred tanks. Among them, fixed beds and trickle beds are widely used in hydrogenation reactions due to their simple operation and suitability for continuous operation. However, in the conventional hydrogenation process, the bubbles enter the reactor in the form of a gas distributor, so that the bubble size in the reactor can often reach more than 100 microns, which greatly reduces the efficiency of the hydrogenation reaction and significantly increases the hydrogen consumption of the whole process.

[0003] In order to achieve sufficient mixing and eliminate the influence of mass transfer in the hydrogenation process, there is also a hydrogenation form using a stirred tank in the industrial production process. However, mechanical stirring has extremely high requirements for the mechanical properties of the catalyst in the hydrogenation process, and strong stirring is likely to cause the crushing of the hydrogenation catalyst. At the same time, when using a stirred tank, the catalyst needs to be separated after the reaction, making the operation process more complicated. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems of poor mass transfer, low reaction efficiency in the fixed bed reactor, easy crushing of the catalyst in the stirred tank reactor and complicated operation existing in the prior art, and provide a liquid-phase hydrogenation reaction device and its application, and a method for preparing CBDO by hydrogenating TMCB, which have the advantages of reducing the influence of mass transfer in the reaction process and improving the efficiency of the hydrogenation reaction.

[0005] In order to achieve the above purpose, on the one hand, the present invention provides a liquid-phase hydrogenation reaction device, which includes a gas-liquid mixing unit, a bubble crushing unit and a reaction unit connected in sequence, so that hydrogen and liquid-phase materials are mixed and the bubbles are crushed before being fed into the reaction unit for hydrogenation reaction; wherein, the setting of the reaction unit can prevent the hydrogenation catalyst from being crushed.

[0006] On the second aspect, the present invention provides the application of the liquid-phase hydrogenation reaction device of the present invention in the preparation of CBDO.

[0007] The third aspect of the present invention provides a method for preparing CBDO by hydrogenating TMCB. This method uses the liquid-phase hydrogenation reaction equipment described in the present invention, including feeding TMCB raw material and hydrogen into the gas-liquid mixing unit, filling a hydrogenation catalyst bed layer in the reaction unit, and enabling the TMCB raw material and hydrogen to enter the reaction unit to contact the hydrogenation catalyst after mixing and fragmentation.

[0008] Through the above technical solution, compared with the prior art, the liquid-phase hydrogenation reaction equipment of the present invention can avoid the fragmentation of the catalyst, strengthen the mass transfer in the hydrogenation process, have a small hydrogen consumption, and improve the reaction efficiency. Description of the Drawings

[0009] Figure 1 are schematic diagrams of the liquid-phase hydrogenation reaction equipment of some embodiments;

[0010] Figure 2 are schematic diagrams of the structure of the fragmentation parts in some embodiments. Detailed Embodiments

[0011] The following will describe in detail the specific embodiments of the present invention with reference to the drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0012] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values and individual point values of each range, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0013] In the present invention, unless otherwise stated, the orientation terms such as "upper, lower, left, right" generally refer to the upper, lower, left, and right shown in the reference drawings; "inner, outer" refer to the inner and outer relative to the contour of each component itself.

[0014] It should be noted that the commonly used hydrogenation reactors in the industry are fixed beds, trickle beds or stirred tanks. Among them, in the hydrogenation process of fixed beds and trickle beds, the bubbles enter the reactor in the form of a gas distributor, so that the bubble size in the reactor is often above 100 microns, resulting in a large hydrogen consumption in the whole process and a low efficiency of the hydrogenation reaction; for the hydrogenation form using a stirred tank, the mechanical properties requirements of the catalyst for the hydrogenation process are extremely high, strong stirring is very likely to cause the fragmentation of the hydrogenation catalyst, and when using a stirred tank, the catalyst needs to be separated after the reaction, making the operation process more complicated.

[0015] To solve the above problems, on the one hand, the present invention discloses a liquid-phase hydrogenation reaction device. The liquid-phase hydrogenation reaction device includes a gas-liquid mixing unit, a bubble breaking unit, and a reaction unit that are connected in sequence along the material flow direction, so that hydrogen and the liquid-phase material are mixed and the bubbles are broken in sequence before being fed into the reaction unit for hydrogenation reaction. Among them, the gas-liquid mixing unit is provided with a hydrogen feed port and a liquid-phase feed port. The reaction unit is configured to prevent the catalyst from being broken. Specifically, the reaction unit includes a fixed-bed reactor without installing any components that cause disturbance (such as stirring, vibration, ultrasound, etc.) to the catalyst bed layer. Thus, compared with the prior art, the breaking of the catalyst can be avoided, the mass transfer in the hydrogenation process can be strengthened, the hydrogen consumption is small, and the reaction efficiency is improved.

[0016] To strengthen the mass transfer in the hydrogenation process and improve the reaction efficiency, in some embodiments of the present invention, the bubble breaking unit includes a conveying pipe. The two ends of the conveying pipe are respectively connected to the discharge part of the gas-liquid mixing unit and the feed part of the reaction unit, and a plurality of breaking parts are installed in the conveying pipe along the material flow direction.

[0017] In some embodiments of the present invention, each breaking part includes n blades arranged circumferentially. The inner ends of the n blades extend towards the axis of the conveying pipe and are connected together. The outer ends of the blades extend towards the pipe wall of the conveying pipe. To improve the breaking efficiency, it is preferably that the length of each blade is the same as the radius of the conveying pipe.

[0018] To improve the breaking efficiency, in some embodiments of the present invention, it is preferably that n≥3, and more preferably n is 3 - 8.

[0019] To improve the breaking efficiency, in some embodiments of the present invention, there is a circumferential misalignment between two adjacent breaking parts. The misalignment angle α is 5 - 30°. Specifically, for example Figure 2 As shown, two adjacent breaking parts are named the first breaking part and the second breaking part. Among them, the second breaking part rotates by an angle α relative to the first breaking part. Thus, the reaction material passing through the conveying pipe can be broken as much as possible.

[0020] To improve the breaking efficiency, in some embodiments of the present invention, N groups of breaking part groups are installed in the conveying pipe along the material flow direction.

[0021] To improve the breaking efficiency, in some embodiments of the present invention, it is preferably that N is 1 - 10.

[0022] To improve the breaking efficiency, in some embodiments of the present invention, it is preferably that each group of breaking part groups includes 360° / (n*α) breaking parts. It can be understood that 360° / (n*α) is rounded to an integer.

[0023] The liquid-phase hydrogenation reaction device of the present invention can make the size of the bubbles in the reactor less than 5 microns, reduce the influence of mass transfer in the reaction process, and improve the hydrogenation reaction efficiency.

[0024] In some embodiments of the present invention, the reaction unit is provided with a feed inlet, a discharge outlet, and a product extraction outlet. Among them, the product extraction outlet is connected to a product tank, the discharge outlet is connected to a gas-liquid separator (such as a decanter), and the gas-phase outlet and the liquid-phase outlet of the gas-liquid separator are each connected to a gas-liquid mixing unit. Among them, the liquid phase enters the gas-liquid mixing unit in a pumped manner.

[0025] In some embodiments of the present invention, the gas-liquid mixing unit includes a static mixer, a venturi tube, and a gas-liquid cyclone, preferably including a static mixer and / or a gas-liquid cyclone.

[0026] In some embodiments of the present invention, it is preferred that the inlet flow rate of the gas-liquid mixing unit is not less than 0.5 m / s. In this way, it has the advantage of uniformly entraining the gas phase into the liquid phase.

[0027] The present invention discloses the application of the foregoing liquid-phase hydrogenation reaction equipment in the preparation of CBDO.

[0028] On the other hand, the present invention provides a method for preparing CBDO by hydrogenating TMCB. This method uses the liquid-phase hydrogenation reaction equipment of the present invention, including feeding hydrogen and TMCB into the gas-liquid mixing unit, filling a hydrogenation catalyst bed in the reaction unit, and allowing hydrogen and TMCB to sequentially pass through mixing and fragmentation and then enter the reaction unit to contact the hydrogenation catalyst.

[0029] In some embodiments of the present invention, the reaction conditions include: a reaction temperature of 80-150 °C, a reaction pressure of 1-5 MPa, and a residence time of 0.5-8 h, preferably 0.5-5 h.

[0030] In some embodiments of the present invention, TMCB is dissolved in butyl acetate to form a TMCB raw material, where the concentration of TMCB is 5-20 wt%, and the feed molar ratio of TMCB to hydrogen is 5-20:1.

[0031] For the present invention, there are no special requirements for the hydrogenation catalyst for preparing CBDO from TMCB. The following is a demonstration, but it does not limit the scope of the present invention. In some embodiments of the present invention, the hydrogenation catalyst can be at least one of a Cu-based catalyst, a Ni-based catalyst, and a Ru-based catalyst.

[0032] The advantages of the present invention will be illustrated by the following examples, but the present invention is not limited thereto.

[0033] Example 1

[0034] This example uses as Figures 1 - 2The liquid-phase hydrogenation reaction equipment shown. In this embodiment, the gas-liquid mixing unit uses a static mixer. Each breaker in the bubble-breaking unit contains 4 blades, that is, n = 4, and the misalignment angle α between adjacent breakers is 5°. Therefore, 18 breakers in this embodiment form a group. The bubble-breaking unit in this embodiment uses 4 groups of breakers, and the breakers are installed in the conveying pipe along the fluid flow direction. The reaction unit in this embodiment uses a fixed-bed reactor, which contains only a catalyst support plate and a catalyst inside, without any other structures. Using H 2 and water as simulation substances to measure the size of H 2 bubbles (measured by a high-speed camera) in the fixed bed of this embodiment. The inlet flow rate of water in the gas-liquid mixing unit in this embodiment is 1 m / s, and the average size of H 2 bubbles measured in the fixed bed is 1.6 μm.

[0035] Example 2

[0036] This embodiment uses the liquid-phase hydrogenation reaction equipment as Figures 1 - 2 shown. The gas-liquid mixing unit in this embodiment uses a hydrocyclone. The structure of the bubble-breaking unit is that each breaker contains 6 blades, that is, n = 6, and the misalignment angle α between adjacent breakers is 10°. Therefore, 6 breakers in this embodiment form a group. The bubble-breaking unit in this embodiment uses 6 groups of breakers, and the breakers are installed in the conveying pipe along the fluid flow direction. The reaction unit in this embodiment uses a fixed-bed reactor, which contains only a catalyst support plate and a catalyst inside, without any other structures. Using H 2 and water as simulation substances to measure the size of H 2 bubbles (measured by a high-speed camera) in the fixed bed of this embodiment. The inlet flow rate of water in the gas-liquid mixing unit in this embodiment is 1 m / s, and the average size of H 2 bubbles measured in the fixed bed is 0.39 μm.

[0037] Example 3

[0038] Different from Example 1, this embodiment uses the liquid-phase hydrogenation reaction equipment of Example 1 to hydrogenate 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB) to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). Among them, TMCB is dissolved in butyl acetate with a concentration of 5 wt%, the feeding rate is 30 mL / min, the feeding molar ratio of TMCB and hydrogen is 7, the catalyst uses a Ru-based catalyst, the residence time is 1 h, the reaction temperature is 100 °C, and the reaction pressure is 3 MPa. The obtained product is analyzed by gas chromatography, and the conversion rate of TMCB is 99.5% and the selectivity of CBDO is 99.2%.

[0039] Example 4

[0040] Different from Example 1, in this example, the liquid-phase hydrogenation reaction equipment of Example 2 was used to hydrogenate 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB) to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). Among them, TMCB was dissolved in butyl acetate with a concentration of 15 wt%, the feeding rate was 30 mL / min, the feeding molar ratio of TMCB to hydrogen was 10, the catalyst used was a Ru-based catalyst, the residence time was 0.8 h, the reaction temperature was 105 °C, and the reaction pressure was 3 MPa. The obtained product was analyzed by gas chromatography, and the conversion rate of TMCB was 99.8% and the selectivity of CBDO was 99.4%.

[0041] Example 5

[0042] Different from Example 1, in this example, the liquid-phase hydrogenation reaction equipment of Example 2 was used to hydrogenate 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB) to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). Among them, TMCB was dissolved in butyl acetate with a concentration of 20 wt%, the feeding rate was 30 mL / min, the feeding molar ratio of TMCB to hydrogen was 5, the catalyst used was a Ru-based catalyst, the residence time was 0.8 h, the reaction temperature was 110 °C, and the reaction pressure was 3 MPa. The obtained product was analyzed by gas chromatography, and the conversion rate of TMCB was 99.3% and the selectivity of CBDO was 98%.

[0043] Comparative Example 1:

[0044] Different from Example 1, in this comparative example, H 2 and water were used as simulation substances. H 2 entered the fixed bed through a 1-μm sintered filter element. Inside the fixed bed reactor, except for the catalyst support plate and the catalyst, there was no any other structure. The average size of the H 2 bubbles was measured to be 30.5 μm by a high-speed camera.

[0045] Comparative Example 2:

[0046] Different from Example 1, in this comparative example, H 2 and water were used as simulation substances. H 2 entered the stirred tank through a 1-μm sintered filter element. The volume of the stirred tank was 2 L and the rotation speed was 800 r / min. The average size of the H 2 bubbles was measured to be 40.5 μm by a high-speed camera.

[0047] Comparative Example 3:

[0048] In this comparative example, the fixed-bed reactor of Comparative Example 1 was used for the hydrogenation of 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB) to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). Among them, TMCB was dissolved in butyl acetate with a concentration of 5 wt%, the feeding rate was 30 mL / min, the feeding molar ratio of TMCB to hydrogen was 7, the catalyst used was a Ru-based catalyst, the residence time was 1 h, the reaction pressure was 3 MPa, and the obtained product was analyzed by gas chromatography. The conversion rate of TMCB was 80%, and the selectivity of CBDO was 67%.

[0049] Comparative Example 4:

[0050] In this comparative example, the stirred-tank reactor of Comparative Example 2 was used for the hydrogenation of 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB) to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). Among them, TMCB was dissolved in butyl acetate with a concentration of 5 wt%, the feeding rate was 30 mL / min, the feeding molar ratio of TMCB to hydrogen was 7, the catalyst used was a Ru-based catalyst, the residence time was 1 h, the reaction pressure was 3 MPa, and the obtained product was analyzed by gas chromatography. The conversion rate of TMCB was 85%, and the selectivity of CBDO was 80%.

[0051] Comparative Example 5

[0052] In this comparative example, the stirred-tank reactor of Comparative Example 2 was used for the hydrogenation of 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB) to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). Among them, TMCB was dissolved in butyl acetate with a concentration of 5 wt%, the feeding rate was 30 mL / min, the feeding molar ratio of TMCB to hydrogen was 50, that is, hydrogen was in great excess, the catalyst used was a Ru-based catalyst, the residence time was 1 h, the reaction pressure was 3 MPa, and the obtained product was analyzed by gas chromatography. The conversion rate of TMCB was 95%, and the selectivity of CBDO was 90%.

[0053] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including the combination of each specific technical feature in any suitable manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods. However, these simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A liquid-phase hydrogenation reaction device, characterized in that, the liquid-phase hydrogenation reaction device includes a gas-liquid mixing unit, a bubble breaking unit, and a reaction unit that are connected in sequence, so that hydrogen and a liquid-phase material are mixed and the bubbles are broken, and then fed into the reaction unit for hydrogenation reaction; wherein, the setting of the reaction unit can prevent the hydrogenation catalyst from being broken.

2. The liquid-phase hydrogenation reaction device according to claim 1, characterized in that, the bubble breaking unit includes a conveying pipe, both ends of the conveying pipe are respectively connected to the discharge part of the gas-liquid mixing unit and the feed part of the reaction unit, and a plurality of breaking parts are installed in the conveying pipe along the material flow direction.

3. The liquid-phase hydrogenation reaction device according to claim 2, characterized in that, each breaking part includes n blades arranged circumferentially, and the inner ends of the n blades extend towards the axis of the conveying pipe and are connected together; preferably n≥3, more preferably n is 3-8; and / or preferably the length of each blade is the same as the radius of the conveying pipe.

4. The liquid-phase hydrogenation reaction device according to claim 3, characterized in that, adjacent two breaking parts are arranged in a circumferential dislocation along the conveying pipe, and the dislocation angle α is 5-30°; and / or a plurality of breaking part groups are installed in the conveying pipe along the material flow direction; preferably N is 1-10; and / or preferably each breaking part group includes 360° / (n*α) breaking parts.

5. The liquid-phase hydrogenation reaction device according to claim 1, characterized in that, the reaction unit is provided with a feed port, a discharge port, and a product sampling port, wherein the discharge port is connected to the feed port of the gas-liquid separator, and the discharge port of the gas-liquid separator is connected to the gas-liquid mixing unit.

6. The liquid-phase hydrogenation reaction device according to claim 5, characterized in that, the gas-liquid mixing unit includes a static mixer, a Venturi tube, and a gas-liquid cyclone; preferably the inlet flow rate of the gas-liquid mixing unit is not less than 0.5 m / s.

7. Application of the liquid-phase hydrogenation reaction device according to any one of claims 1-6 in the preparation of CBDO.

8. A method for hydrogenating TMCB to prepare CBDO, characterized in that, this method uses the liquid-phase hydrogenation reaction device according to any one of claims 1-6, and includes feeding TMCB raw material and hydrogen into the gas-liquid mixing unit, filling a hydrogenation catalyst bed layer in the reaction unit, and making the TMCB raw material and hydrogen enter the reaction unit to contact with the hydrogenation catalyst after mixing and breaking.

9. The method according to claim 8, wherein, the reaction conditions include: reaction temperature 80-150 °C, reaction pressure 1-5 MPa, residence time 0.5-8 h, preferably 0.5-5 h.

10. The method according to claim 8 or 9, wherein, the concentration of TMCB in the TMCB raw material is 5-20 wt%, and the feed molar ratio of TMCB to hydrogen is 5-20:1; and / or the hydrogenation catalyst can adopt at least one of Cu-based catalyst, Ni-based catalyst, and Ru-based catalyst.

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