Crushing structure, gas-liquid reaction equipment and method for preparing 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol

Abstract

The invention relates to the field of gas-liquid reaction, and discloses a crushing structure, gas-liquid reaction equipment and a method for preparing 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, the crushing structure comprises a pipeline used for material circulation and a plurality of crushing parts arranged in the pipeline, the crushing parts are arranged in the pipeline, and the gas-liquid reaction equipment is arranged in the pipeline. The multiple crushing parts are arranged in the pipe length direction of the pipeline at intervals, every two adjacent crushing parts are arranged in a staggered mode in the circumferential direction of the pipeline, each crushing part comprises n (n is larger than or equal to 3) blades arranged in the circumferential direction of the pipeline, and the inner ends of the n blades extend towards the axis of the pipeline and are connected into a whole. The device has the advantages that the heat generated in the strong exothermic reaction process is quickly removed, and the uniformity of the temperature of the reaction bed layer is ensured.

Description

Technical Field

[0001] The present invention relates to the field of gas-liquid reactions, and particularly to a crushing structure, a gas-liquid reaction device, and a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Background Art

[0002] Hydrogenation reactions are widely used in industrial production processes, such as hydrogenation of ketones to alcohols, hydrogenation of nitriles to amines, and hydrogenation of acid anhydrides to alcohols. Currently, 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. The hydrogenation process is often a highly exothermic process. However, due to the fixed bed structure, heat cannot be removed in a timely manner during the reaction process. With the accumulation of heat, it is easy to cause a sharp rise in the bed temperature for highly exothermic processes, which not only affects the catalyst life but also leads to production safety problems.

[0003] At the same time, catalytic hydrogenation is often a gas-liquid-solid three-phase reaction process, and mass transfer has a great influence on the reaction efficiency. In the conventional fixed bed hydrogenation process, the bubbles can often reach more than 100 microns, greatly reducing the opportunity for gas-liquid-solid contact and reducing the reaction efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a crushing structure, a gas-liquid reaction device, and a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol, which have the advantage of quickly removing the heat generated during the highly exothermic reaction process and ensuring the uniformity of the reaction bed temperature.

[0005] To achieve the above purpose, on the one hand, the present invention provides a crushing structure, which includes a pipeline for flowing materials and crushing members arranged in the pipeline. There are multiple crushing members, and the multiple crushing members are arranged at intervals along the pipe length direction of the pipeline, and adjacent two crushing members are arranged in a circumferential dislocation along the pipeline. Each crushing member includes n (n≥3) blades arranged along the circumferential direction of the pipeline, and the inner ends of the n blades extend towards the axis of the pipeline and are connected together.

[0006] On the second aspect, the present invention provides a gas-liquid reaction device, which includes a gas-liquid reaction unit and a heat exchange unit. The gas-liquid reaction unit is provided with a feed part and a circulating discharge part. Among them, the feed part of the heat exchange unit is connected to the circulating discharge part, and the discharge part of the heat exchange unit is connected to the feed part of the gas-liquid reaction unit. The heat exchange unit includes a heat exchange part, a mixing part, and a crushing part, and the crushing part includes the crushing structure of the present invention.

[0007] The third aspect of the present invention provides a method for preparing 2,2,4,4 - tetramethyl - 1,3 - cyclobutanediol by hydrogenating 2,2,4,4 - tetramethyl - 1,3 - cyclobutanedione. The method uses the gas - liquid reaction equipment described in any one of claims 1 - 7, including feeding 2,2,4,4 - tetramethyl - 1,3 - cyclobutanedione and hydrogen into the gas - liquid reaction unit, and reacting the two in the presence of a hydrogenation catalyst.

[0008] Through the above - mentioned technical solution, the reaction materials of the present invention are heat - exchanged, mixed and broken in the heat - exchange unit and then returned to the reaction unit, which can timely remove the heat in the reaction process and strengthen mass transfer, ensure the uniformity of the reaction bed temperature, improve the reaction efficiency. Further, the present invention can make the temperature difference of the reaction bed not more than 2 °C, preferably not more than 1 °C. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of the gas - liquid reaction equipment of some embodiments of the present invention;

[0010] Figure 2 is a schematic diagram of the heat - exchange unit in some embodiments of the present invention;

[0011] Figure 3 is a schematic diagram of the heat - exchange unit in some other embodiments of the present invention;

[0012] Figure 4 is a schematic diagram of the crushing part in some embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0014] 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, the endpoint values of each range, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values 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.

[0015] In the present invention, unless otherwise stated, the orientation terms such as "upper, lower, left, right" generally refer to the upper, lower, left, right shown in the reference drawings; "inner, outer" refer to the inner and outer of the contour of each component itself.

[0016] On the one hand, the present invention provides a crushing structure, which includes a pipeline for flowing materials and crushing members arranged in the pipeline. There are multiple crushing members, and the multiple crushing members are arranged at intervals along the pipe length direction of the pipeline, and are circumferentially offset between adjacent two crushing members. Each crushing member includes n (n≥3) blades arranged along the circumferential direction of the pipeline. The inner ends of the n blades extend towards the axis of the pipeline and are connected together, and the outer ends extend towards the pipe wall of the pipeline.

[0017] In some embodiments of the present invention, the length (dimension in the radial direction of the pipeline) of each blade is the same as the radius of the pipeline.

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

[0019] In some embodiments of the present invention, the circumferential misalignment angle α between adjacent two crushing members along the pipeline is 5 - 30°. Specifically, for example Figure 4 As shown, the adjacent two crushing members are named the first crushing member and the second crushing member. Among them, the second crushing member rotates by an angle α relative to the first crushing member. In this way, the reaction materials passing through the conveying pipe can be crushed as much as possible.

[0020] In some embodiments of the present invention, N groups of crushing member groups are installed along the pipe length direction in the pipeline. Preferably, each group of crushing member groups includes 360° / (n*α) crushing members. It can be understood that 360° / (n*α) is rounded to an integer.

[0021] In some embodiments of the present invention, preferably N is 1 - 20.

[0022] According to the foregoing disclosure, using the crushing structure of the present invention can significantly reduce the bubble diameter, which can be lower than 5μm.

[0023] The present invention discloses a gas - liquid reaction device, as Figure 1 shown, the gas - liquid reaction device includes:

[0024] A gas-liquid reaction unit and a heat exchange unit. The gas-liquid reaction unit is provided with a feed section and a recycled product discharge section. Among them, the feed section of the heat exchange unit for the feed reaction material is connected to the recycled product discharge section, and the discharge section of the heat exchange unit for the reaction material after heat exchange is connected to the feed section of the gas-liquid reaction unit. The heat exchange unit includes a heat exchange section, a mixing section, and a crushing section, and the crushing section is set as the crushing structure of the present invention. In an exothermic reaction, the heat in the reaction unit can be removed from the reactor in time, the heat in the reaction process can be removed in time, the occurrence of side reactions can be inhibited, and the service life of the catalyst can be prevented from being affected. At the same time, the reaction material returns to the reaction unit after heat exchange, mixing, and crushing in the heat exchange unit, which can strengthen mass transfer and improve the reaction efficiency. Of course, it can be understood that the gas-liquid reaction equipment of the present invention is not limited to exothermic reactions only. When applied to endothermic reactions, the heat exchange section can be used for circulating heating.

[0025] In some embodiments of the present invention, the heat exchange unit can be set in Form 1 or Form 2, or in a parallel form of Form 1 and Form 2 to increase the processing capacity. Among them:

[0026] Form 1: As Figure 2 shown, along the material flow direction, the heat exchange section, the mixing section, and the crushing section in the heat exchange unit are connected in sequence;

[0027] Form 2: As Figure 3 shown, the heat exchange section and the crushing section are combined into one body to form a heat exchange and crushing section, so that the material is crushed while being heat exchanged, improving the processing efficiency. Among them, the feed inlet of the heat exchange and crushing section is connected to the discharge outlet of the mixing section. It can be understood that, compared with Form 1, Form 2 has a smaller floor area.

[0028] In some embodiments of the present invention, a gas-liquid separator is connected between the feed section and the recycled product discharge section of the heat exchange unit. There are no special requirements for the gas-liquid separator in the present invention, as long as it can achieve the gas-liquid separation of the material. The following is a demonstration of the gas-liquid separator, but the present invention is not limited thereto. In some embodiments of the present invention, the gas-liquid separator is set as a decanter.

[0029] In some embodiments of the present invention, the heat exchange unit is provided with a first gas phase inlet G1, a second gas phase inlet G2, a first liquid phase inlet L1, and a second liquid phase inlet L2. Among them, the first gas phase inlet G1 is connected to the gas phase outlet of the gas-liquid separator to recycle the unreacted gas phase back to the gas-liquid reaction unit; the second gas phase inlet G2 is used for feeding fresh gas phase; the first liquid phase inlet L1 is connected to the liquid phase outlet of the gas-liquid separator (and a power device in the prior art, such as a transfer pump, is provided on this connection pipeline) to recycle the unreacted liquid phase back to the gas-liquid reaction unit; the second liquid phase inlet L2 is used for feeding fresh liquid phase.

[0030] In some embodiments of the present invention, when the heat exchange unit is in Form 1, the first liquid-phase feed port L1 is disposed in the heat exchange section, and the second liquid-phase feed port L2, the first gas-phase feed port G1, and the second gas-phase feed port G2 are disposed in the mixing section.

[0031] In some embodiments of the present invention, when the heat exchange unit is in Form 2, the first gas-phase inlet G1, the second gas-phase inlet G2, the first liquid-phase inlet L1, and the second liquid-phase inlet L1 are disposed in the mixing section.

[0032] In some embodiments of the present invention, the heat exchange section includes a heat exchanger (such as a shell-and-tube heat exchanger), and the mixing section includes at least one of a static mixer, a Venturi tube, and a gas-liquid cyclone.

[0033] In some embodiments of the present invention, the gas-liquid reaction unit includes a fixed-bed reactor.

[0034] In some embodiments of the present invention, when the heat exchange unit is in Form 2, the heat exchange section includes a shell side and a tube side located in the shell side, wherein the shell side is used for circulating the heat exchange medium, and the tube side is provided with the aforementioned crushing structure of the present invention for circulating and crushing the reaction material. Specifically, for example, the heat exchanger of the heat exchange section is a shell-and-tube heat exchanger, the material flows through the tube side of the heat exchanger, and the heat exchange medium flows through the shell side, and N groups of the aforementioned crushing element groups are installed along the tube length direction in the tube side.

[0035] The present invention can introduce the substances in the reaction bed layer into the heat exchange unit, so that the heat generated by the highly exothermic hydrogenation process can be quickly removed, ensuring the uniformity of the reaction bed layer temperature, and the hydrogenation reaction efficiency can be improved by strengthening mass transfer.

[0036] On the basis of the foregoing disclosure, the present invention discloses a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol by hydrogenating 2,2,4,4-tetramethyl-1,3-cyclobutanedione. This method uses the gas-liquid reaction equipment of the present invention, including feeding 2,2,4,4-tetramethyl-1,3-cyclobutanedione and hydrogen into the gas-liquid reaction unit, and reacting the two in the presence of a hydrogenation catalyst.

[0037] 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 the liquid-phase 2,2,4,4-tetramethyl-1,3-cyclobutanedione of 0.5 - 8 h, preferably 0.5 - 5 h.

[0038] In some embodiments of the present invention, the concentration of the raw material 2,2,4,4-tetramethyl-1,3-cyclobutanedione in the hydrogenation process is controlled to be 5 - 50 wt%, preferably 10 - 30 wt%.

[0039] For the present invention, there are no special requirements for the hydrogenation catalyst for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol from 2,2,4,4-tetramethyl-1,3-cyclobutanedione. The following is an exemplary description, but it does not limit the scope of the present invention thereby. 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.

[0040] The advantages of the present invention will be illustrated by the following examples, but the present invention is not limited thereto.

[0041] Example 1

[0042] This example uses a gas-liquid reaction device as described in Figures 1 - 4 . Among them, the heat exchange unit in this example adopts Form 1 ( Figure 2 ). Among them, the gas-liquid reaction unit is set as a fixed-bed reactor, the heat exchanger adopts a shell-and-tube heat exchanger, the mixing unit adopts a static mixer, and the structure of the crushing unit is that each crushing part contains 4 blades, that is, n = 4, and the angle α between adjacent crushing parts is 5°. Therefore, 18 crushing parts in this example are a group, and this example's bubble crushing unit adopts 4 groups of crushing parts, and the crushing parts are installed in the pipeline along the fluid flow direction. The above gas-liquid reaction device is 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 is dissolved in butyl acetate with a concentration of 15 wt%, the feeding rate is 30 mg / min, sufficient hydrogen is introduced, the catalyst adopts a Ru-based catalyst, the reaction temperature is 100 °C, the residence time is 1 h, the reaction pressure is 3 MPa, and the obtained product is analyzed by gas chromatography. The TMCB conversion rate is 99.2%, the CBDO selectivity is 99.8%, and the bed temperature difference is 0.57 °C.

[0043] Example 2

[0044] Different from Example 1, the heat exchange unit in this example adopts Form 2 ( Figure 3) The mixing unit uses a static mixer, and the heat exchange and crushing section uses a shell-and-tube heat exchanger. The cooling medium flows through the shell side, and crushing parts are installed in each tube side. Each crushing part contains 4 blades, that is, n = 4, and the angle α between adjacent crushing parts is 5°. Therefore, 18 crushing parts in this embodiment are a group, and 4 groups of crushing parts are installed in each tube side of this embodiment. Using the above gas-liquid reaction equipment for the hydrogenation of 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB) to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO), where TMCB is dissolved in butyl acetate with a concentration of 30 wt%, the feeding rate is 30 mg / min, sufficient hydrogen is introduced, the catalyst uses a Ru-based catalyst, the reaction temperature is 100 °C, the residence time is 1 h, the reaction pressure is 3 MPa, and the others are the same as in Example 1. The obtained product is analyzed by gas chromatography, and the TMCB conversion rate is 99.3%, the CBDO selectivity is 99.9%, and the bed temperature difference is 0.28 °C.

[0045] Example 3

[0046] Different from Example 1, n = 8, and the angle α between adjacent crushing parts is 10°. Therefore, 5 crushing parts in this embodiment are a group, and 10 groups of crushing parts are installed in each tube side of this embodiment. Using the above gas-liquid reaction equipment for the hydrogenation of 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB) to prepare 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO), where TMCB is dissolved in butyl acetate with a concentration of 25 wt%, the feeding rate is 30 mg / min, sufficient hydrogen is introduced, the catalyst uses a Ru-based catalyst, the reaction temperature is 100 °C, the residence time is 3 h, the reaction pressure is 4.7 MPa, and the others are the same as in Example 1. The obtained product is analyzed by gas chromatography, and the TMCB conversion rate is 99.5%, the CBDO selectivity is 99.7%, and the bed temperature difference is 0.32 °C.

[0047] Comparative Example 1

[0048] This comparative example uses a conventional fixed-bed hydrogenation device, and hydrogen enters the reaction bed layer in the form of a gas distributor. Among them, TMCB is dissolved in butyl acetate with a concentration of 15 wt%, the feeding rate is 30 mg / min, sufficient hydrogen is introduced, the catalyst uses a Ru-based catalyst, the residence time is 1 h, the reaction pressure is 3 MPa, and the obtained product is analyzed by gas chromatography, and the TMCB conversion rate is 83.7%, the CBDO selectivity is 32.2%, the bed temperature difference is 10.33 °C, and the bed temperature continues to rise, resulting in the forced stop of the experiment.

[0049] Comparative Example 2

[0050] Different from Example 1, a filter with a pore size of 5 microns was used to break the gas-liquid mixture. The product obtained under the same reaction conditions was analyzed by gas chromatography, and the conversion rate of TMCB was 97.3%, the selectivity of CBDO was 98.1%, and the temperature difference across the bed was 1.35°C.

[0051] 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 any suitable combination of individual specific technical features. 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 crushing structure, characterized in that, the crushing structure includes a pipeline for material flow and crushing members arranged in the pipeline. There are multiple crushing members, and the multiple crushing members are arranged at intervals along the pipe length direction of the pipeline and are circumferentially offset between adjacent two crushing members. Each crushing member includes n (n≥3) blades arranged along the circumferential direction of the pipeline, and the inner ends of the n blades extend towards the axis of the pipeline and are connected together.

2. The crushing structure according to claim 1, characterized in that, the circumferential misalignment angle α between adjacent two crushing members is 5-30°; and / or n is 3-8; and / or the length of each blade is the same as the radius of the pipeline; and / or N groups of crushing member groups are installed in the pipeline along the pipe length direction. Preferably, each group of crushing member groups includes 360° / (n*α) crushing members; and / or preferably N is 1-20.

3. A gas-liquid reaction device, characterized in that, the gas-liquid reaction device includes: a gas-liquid reaction unit and a heat exchange unit. The gas-liquid reaction unit is provided with a feed part and a circulating discharge part. Among them, the feed part of the heat exchange unit is communicated with the circulating discharge part, the discharge part of the heat exchange unit is communicated with the feed part of the gas-liquid reaction unit, the heat exchange unit includes a heat exchange part, a mixing part and a crushing part, and the crushing part includes the crushing structure according to claim 1 or 2.

4. The gas-liquid reaction device according to claim 3, characterized in that, the setting of the heat exchange unit includes: Form 1: Along the material flow direction, the heat exchange part, the mixing part and the crushing part in the heat exchange unit are sequentially communicated; and / or Form 2: The heat exchange part and the crushing part are combined into one body to form a heat exchange and crushing part, so that the material is crushed while being heated, and the feed port of the heat exchange and crushing part is communicated with the discharge port of the mixing part.

5. The gas-liquid reaction device according to claim 3 or 4, characterized in that, a gas-liquid separator is communicated between the feed part of the heat exchange unit and the circulating discharge part; and / or the heat exchange unit is provided with a first gas phase inlet (G1), a second gas phase inlet (G2), a first liquid phase inlet (L1) and a second liquid phase inlet (L2). Among them, the first gas phase inlet (G1) is communicated with the gas phase outlet of the gas-liquid separator, the second gas phase inlet (G2) is used for feeding fresh gas phase, the first liquid phase inlet (L1) is communicated with the liquid phase outlet of the gas-liquid separator, and the second liquid phase inlet (L2) is used for feeding fresh liquid phase.

6. The gas-liquid reaction device according to claim 5, characterized in that, when the heat exchange unit is in Form 1, the first liquid phase feed port (L1) is arranged in the heat exchange part, and the second liquid phase feed port (L2), the first gas phase feed port (G1) and the second gas phase feed port (G2) are arranged in the mixing part; or when the heat exchange unit is in Form 2, the first gas phase inlet (G1), the second gas phase inlet (G2), the first liquid phase inlet (L1) and the second liquid phase inlet (L1) are arranged in the mixing part.

7. The gas-liquid reaction device according to any one of claims 3-6, characterized in that, The heat exchange section includes a heat exchanger, and the mixing section includes a static mixer, at least one of a Venturi tube and a gas-liquid cyclone; and / or The gas-liquid reaction unit includes a fixed bed reactor.

8. The gas-liquid reaction equipment according to claim 4, characterized in that when the heat exchange unit is in Form 2, the heat exchange section includes a shell side and a tube side located in the shell side, wherein the shell side is used for circulating a heat exchange medium, and the tube side is arranged in a broken structure for circulating and breaking reaction materials.

9. A method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanediol by hydrogenating 2,2,4,4-tetramethyl-1,3-cyclobutanedione, characterized in that the method uses the gas-liquid reaction equipment according to any one of claims 3-8, and includes feeding 2,2,4,4-tetramethyl-1,3-cyclobutanedione and hydrogen into the gas-liquid reaction unit, and reacting the two in the presence of a hydrogenation catalyst.

10. The method according to claim 9, wherein the reaction conditions include: a reaction temperature of 80-150 °C, a reaction pressure of 1-5 MPa, and a residence time of the liquid-phase 2,2,4,4-tetramethyl-1,3-cyclobutanedione of 0.5-8 h, preferably 0.5-5 h; and / or controlling the concentration of the raw material 2,2,4,4-tetramethyl-1,3-cyclobutanedione in the hydrogenation process to be 5-50 wt%, more preferably 10-30 wt%; and / or the hydrogenation catalyst can be at least one of a Cu-based catalyst, a Ni-based catalyst, and a Ru-based catalyst.

Images