Microwave reaction pipeline and microwave tubular continuous flow reactor

Abstract

The utility model relates to the technical field of industrial reactors, in particular to a microwave reaction pipeline and a microwave tubular continuous flow reactor. The microwave reaction pipeline comprises a reaction pipeline body and a microwave reaction cavity wrapping the reaction pipeline body, a microwave generator is arranged on the microwave reaction cavity, the reaction pipeline body is a ceramic pipeline, a wave-transparent heat preservation layer is laid on the outer surface of the reaction pipeline body, and connecting components independent of the reaction pipeline body are arranged at the input end and the output end of the reaction pipeline body. The connecting members are located at the two ends of the microwave reaction cavity, the microwave reaction cavity and the connecting members are arranged in two halves, and the microwave reaction cavity is of a regular polyhedron structure. The microwave reaction pipeline is wear-resistant and corrosion-resistant, the structural matching of the connecting component and the microwave reaction cavity is convenient to assemble, the reaction pipeline is not easy to crack, the arrangement form of the microwave generator enables the efficiency of converting microwave energy into heat energy to be higher, and solid or corrosive materials in the ceramic pipeline can be uniformly heated.

Description

Technical Field

[0001] The utility model relates to the technical field of industrial reactors, in particular to a microwave reaction pipeline and a microwave reactor. Background Art

[0002] A tubular reactor is a type of reactor consisting of multiple sections of pipelines connected in series or in parallel. It is generally used in industry for reactions between gaseous materials and liquid materials, or between liquid materials and liquid materials.

[0003] Chinese patent document CN201711147U discloses a high-power microwave reactor, which includes a microwave device, a tubular reactor, and a shielding tube. The tubular reactor passes through a microwave reaction chamber and is integrated with the microwave device to form a microwave tubular reactor. The two ends are open, one end is the input end, and the other end is the output end. Each tubular reactor can be equipped with 1-4 microwave devices, and adjacent tubular reactors are connected by pipelines. The shielding tube is coated on the outside of the tubular reactor and welded to the microwave reaction chamber. This solution can meet the needs of continuous flow microwave heating processes, improve the uniformity of reaction liquid heating, and is conducive to the large-scale application of microwave organic synthesis technology in the chemical industry. This solution has a short service life of the tubular reactor when the reactants contain particulate matter and are corrosive.

[0004] On the other hand, Chinese patent document CN214789504U discloses a high-life wear-resistant ceramic pipe, including a ceramic pipe body, the ceramic pipe body having an external protective sleeve, the two ends of the external protective sleeve respectively having a left connecting flange and a right connecting flange, an inner ceramic liner for improving the wear resistance of the ceramic pipe body is provided on the inner side of the external protective sleeve, and a reinforced metal sleeve is provided on the inner side of the internal ceramic liner. This solution makes the internal structure of the pipe harder and the protective effect better by providing an internal ceramic liner and a reinforced metal sleeve. However, due to the presence of the reinforced metal sleeve, it cannot be applied to microwave tubular reactors. Even if the reinforced metal sleeve is removed, since microwave heating is accompanied by high temperature and a certain pressure, the ceramic tube is prone to rupture due to the different thermal expansion coefficient from the external protective sleeve. On the other hand, since the ceramic tube material is relatively brittle, the installation process of the ceramic tube and the external protective sleeve and the process of installing the ceramic liner inside the ceramic tube are prone to rupture during installation and maintenance. Summary of the Invention

[0005] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a microwave reaction pipe which uses a ceramic pipe as a direct reaction container and is suitable for heating or promoting the reaction of solid or corrosive materials, and the ceramic pipe is not easily broken during use.

[0006] In order to achieve the above purpose, the technical solution of the utility model is as follows:

[0007] The microwave reaction pipe comprises a reaction pipe and a microwave reaction cavity wrapping the reaction pipe. A microwave generator is arranged on the microwave reaction cavity. The reaction pipe has an input end and an output end. The reaction pipe is a ceramic pipe. The reaction pipe is provided with connecting components independent of the reaction pipe at its input end and output end. The connecting components are located at both ends of the microwave reaction cavity.

[0008] The inventive concept of the present invention is as follows: First, the microwave reaction chamber in Chinese patent document CN201711147U is replaced with the middle section of the outer protective sleeve in Chinese patent document CN214789504U, so that the ceramic pipe and the microwave reactor are combined to provide a microwave reaction site for solid-containing or corrosive materials. Secondly, due to the temperature increase caused by microwave heating, when the connecting member and the microwave reaction chamber are heated and axially expand, compared with the outer protective sleeve in Chinese patent document CN214789504U, the microwave reaction chamber is more easily deformed and the deformation is offset, so the connecting members are less likely to loosen, which is beneficial to the stability of the connection. Third, due to the gap between the ceramic pipe and the microwave reaction chamber, when the ceramic pipe and the microwave reaction chamber are heated and radially expand, they do not affect each other, and the ceramic pipe will not be subjected to large-area radial compression and rupture.

[0009] As an improvement, the reaction tube is coated with a wave-transmitting insulation layer, with the microwave reaction chamber located outside the wave-transmitting insulation layer. This layer has two functions: first, it reduces the probability of damage to the ceramic tube during installation; second, it reduces heat transfer, facilitating sufficient heating of the material while reducing heat transfer to the microwave reaction chamber, thereby protecting the microwave generator.

[0010] As an improvement, the connecting member includes a flange and a support ring, one side of the support ring is fixed to the end of the microwave reaction chamber, and the other side of the support ring is a flange. The flange is used to connect to the flange of the adjacent pipeline to press the ends of the adjacent reaction pipelines tightly.

[0011] As an alternative solution, the connecting member is a flange, and a fixing ring for connecting to the flange is provided at each end of the microwave reaction cavity.

[0012] As a further improvement, the connecting member is provided in two halves, which are combined to form a complete connecting member. The two-halves are convenient for installation of the reaction pipe and maintenance.

[0013] As a further improvement, the microwave reaction chamber is provided in two halves, which are combined to form a complete microwave reaction chamber. This solution also facilitates the installation and maintenance of the microwave reaction chamber.

[0014] As an improvement, the microwave reaction cavity is circular or a regular polyhedron structure, and at least one group of microwave generators is arranged along the length direction of the microwave reaction cavity.

[0015] As a further improvement, the microwave reaction chamber has a regular hexahedral structure, with two sets of microwave generators arranged along its length, one on each side. Using a horizontally and vertically staggered distribution pattern, two sets of microwave generators are placed in one reaction tube, for a total of six. This arrangement has been shown to achieve high heating efficiency.

[0016] As a further improvement, the reaction pipe has outward-turned portions at its input end and output end, and the outward-turned portions protrude from the end surface of the connecting component to facilitate the installation of the sealing gasket.

[0017] Another object of the present application is to provide a microwave reactor, comprising the above-mentioned microwave reaction pipes connected in sequence to form a main reaction pipe, and sealing gaskets are provided on the contact surfaces of adjacent microwave reaction pipes.

[0018] As an improvement, the sealing gasket has an I-shaped cross-section. This facilitates installation and, when adjacent pipes are misaligned, material can easily accumulate at the misaligned location. The gasket has a flat portion that guides the material, preventing it from accumulating at the misaligned location. Third, the I-shaped gasket achieves bidirectional sealing in both the axial and radial directions, resulting in a relatively effective seal.

[0019] As a further improvement, the main reaction tube is provided with a back-mixing tube, one for every at least one microwave reaction tube. Each back-mixing tube is provided with a back-mixing material inlet pipe connected to the reacted material. The back-mixing material inlet pipe can reintroduce unreacted reaction materials into the reaction tube for further reaction and can also flush the inner surface of the reaction tube, reducing the probability of material deposition.

[0020] As a further improvement, the number of the main reaction pipes is at least two, the main reaction pipes are connected by auxiliary reaction pipes, and a sealing gasket is provided at the connection between the main reaction pipe and the auxiliary reaction pipe.

[0021] As an improvement, the microwave reactor includes an external box.

[0022] As a further improvement, the external box is arranged horizontally, the main reaction pipe is arranged horizontally along the outer wall of the external box, the number of the main reaction pipes is at least 2, and the main reaction pipes are connected by auxiliary reaction pipes.

[0023] As an alternative, the external box is arranged vertically, the main reaction pipe is arranged vertically along the outer wall of the external box, the number of the main reaction pipes is at least 2, and the main reaction pipes are connected by auxiliary reaction pipes.

[0024] As a further improvement, the side reaction pipeline is provided with an inspection port.

[0025] As a further improvement, the power supply of the microwave generator is located on the top of the external box.

[0026] In summary, the present invention utilizes a ceramic pipe as the direct reaction site, offering wear and corrosion resistance. Its structural coordination with connecting components and the microwave reaction chamber facilitates assembly and resists cracking. The microwave generator's layout effectively converts microwave energy into heat, enabling uniform heating of solid or corrosive materials within the ceramic pipe. The microwave reactors are housed within a single housing, resulting in a compact structure that facilitates assembly and transport, providing increased flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of the microwave reaction pipeline in Example 1 of the present utility model;

[0028] Figure 2 for Figure 1 sectional view of

[0029] Figure 3 This is a schematic structural diagram of the microwave reaction pipeline in Example 2 of the present utility model;

[0030] Figure 4 for Figure 3 sectional view of

[0031] Figure 5 This is an exploded view of the microwave reaction cavity and the connecting components in Example 2 of the present utility model;

[0032] Figure 6 This is a schematic diagram of the connection relationship between two microwave reaction pipes in Example 3 of the present utility model;

[0033] Figure 7 This is a schematic diagram of the overall structure of Example 3 of the present utility model;

[0034] Figure 8 for Figure 6 sectional view of

[0035] Figure 9 for Figure 8 Enlarged view of middle part B;

[0036] Figure 10 for Figure 7 Enlarged view of part A in the middle;

[0037] Figure 11 This is a schematic diagram of the overall structure of Example 4 of the present utility model;

[0038] Figure 12 This is the first simulation verification of the arrangement and results of this utility model;

[0039] Figure 13 This is the second simulation verification arrangement and results of this utility model;

[0040] Figure 14 This is the third simulation verification arrangement and result of this utility model.

[0041] In the figure: 10, reaction pipe; 11, outward-turned part; 12, bracket; 20, microwave reaction chamber; 21, fixing ring; 30, microwave generator; 31, cooling water system; 32, power supply; 41, flange; 42, support ring; 50, wave-transmitting insulation layer; 60, sealing gasket; 70, back-mixing pipe; 71, back-mixing material input pipe; 80, auxiliary reaction pipe; 81, inspection port; 90, external box. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art may make various changes or modifications to the present invention, and that such equivalents also fall within the scope of the claims appended hereto. Example 1

[0043] The microwave reaction pipe described in this application is a unit pipe that can be connected to other pipes to form the required reaction reactor length. Figure 1 、 Figure 2 The main body of the microwave reaction tube shown is the reaction tube 10, a ceramic tube with an inner diameter of 100-500 mm and a length of 400-800 mm. Both the input and output ends of the reaction tube 10 are provided with an outward-turned portion 11, which protrudes from the end surface of the connecting member. The outward-turned portion 11 increases the contact area with the sealing gasket 60 to improve the sealing effect and also provides a force-bearing point for the connecting member. The reaction tube 10 is surrounded by the microwave reaction cavity 20 and the connecting member. The connecting member is provided independently of the reaction tube 10. When the connecting member and the reaction tube 10 expand due to heat, both expand and extend in their respective axial directions.

[0044] The microwave reaction chamber 20 is a pentagonal structure, with a microwave generator 30 arranged on each side. The microwave generator 30 is equipped with a cooling water system 31. The cooling water system 31 is conventional and will not be described in detail. As is common sense, air cooling or other technical means can also be added to cool the microwave generator 30.

[0045] like Figure 1 、 Figure 2As shown, a retaining ring 21 is provided on each side of the microwave reaction chamber 20 for securing the connection member. The retaining ring 21 is arranged axially along the reaction tube 10. The inner diameter of the retaining ring 21 is larger than the outer diameter of the outward-turned portion 11, allowing the microwave reaction chamber 20 to be inserted from the end of the reaction tube 10. The connection member includes a metal flange 41 and a support ring 42. One side of the support ring 42 can be inserted into the gap between the retaining ring 21 and the reaction tube 10 to temporarily secure the connection member to the end of the microwave reaction chamber 20. The other side of the support ring 42 is a flange 41, which abuts against the outward-turned portion 11.

[0046] The flange 41 and the support ring 42 are both arranged in two halves, an upper half and a lower half, which are combined to form a complete connecting member. The lower half of the support ring 42 is also provided with a bracket 12 for fixing the microwave reaction tube to the ground or other components. Example 2

[0047] like Figure 3 、 Figure 4 、 Figure 5 As shown, the difference between this embodiment and embodiment 1 is that:

[0048] 1. A wave-transmitting heat-insulating layer 50 is applied to the surface of the reaction pipe 10, and the microwave reaction cavity 20 is located outside the wave-transmitting heat-insulating layer 50. The wave-transmitting heat-insulating layer 50 may be made of alumina, and its thickness is 5-20 mm.

[0049] 2. A fixing ring 21 for connecting to a flange 41 is provided at each end of the microwave reaction chamber 20. The fixing ring 21 is perpendicular to the central axis of the reaction tube 10. The connecting member is the flange 41. The flange 41 and the fixing ring 21 are provided with screw holes of the same number and aperture. Figure 6 As shown, when adjacent microwave reaction pipes are connected, the flanges 41 at both ends and the fixing rings 21 are fixed together with bolts.

[0050] 3. The microwave reaction chamber 20 and the connecting member are both arranged in two halves: the microwave reaction chamber 20 is divided into an upper half and a lower half, and the connecting member is divided into a left half and a right half, which are combined to form a complete microwave reaction chamber 20 and the connecting member.

[0051] 4. The microwave reaction chamber 20 is a regular hexahedron. Two groups of microwave generators 30 are arranged along the length of the microwave reaction chamber 20. Each group of microwave generators 30 is arranged with one microwave generator 30 every other face. Within each group of microwave generators 30, adjacent microwave generators 30 are arranged perpendicular to each other. Example 3

[0052] like Figure 7The figure shows a microwave reactor, which includes a horizontally arranged outer housing 90 and reaction pipes located therein. The reaction pipes include a main reaction pipe and a secondary reaction pipe 80, which is mainly used to connect to the main reaction pipe. The main reaction pipe is mainly composed of microwave reaction pipes connected in sequence, and is provided with a microwave generator 30. The power supply 32 of the microwave generator 30 is all located at the top of the outer housing 90. The secondary reaction pipe 80 is not provided with a microwave generator 30, which mainly serves as a connection. Of course, microwave generators 30 can also be provided on the secondary reaction pipe 80. The main reaction pipes are arranged horizontally along the outer wall of the outer housing 90. There are four main reaction pipes, and the main reaction pipes are connected by secondary reaction pipes 80.

[0053] The contact surfaces of adjacent microwave reaction pipes are provided with sealing gaskets 60. The connection between the auxiliary reaction pipe 80 and the main reaction pipe is also provided with the same sealing gasket 60. Figure 8 、 Figure 9 As shown, the sealing gasket 60 is located between the two outward-turned portions 11. It is made of polytetrafluoroethylene and has an I-shaped cross-section. The bottom end of the I-shaped sealing gasket 60 protrudes in an arc shape and adheres to the inner wall of the reaction tube 10, while the top end of the I-shaped sealing gasket 60 buckles on the top of the two outward-turned portions 11.

[0054] like Figure 10 As shown, the main reaction tube is provided with a back-mixing tube 70, with one back-mixing tube 70 provided every two microwave reaction tubes. The back-mixing tube 70 is provided with a back-mixing material input tube 71 for communicating with the reacted material. The arrangement of the back-mixing material input tube 71 is a common connection method and will not be described in detail. As an obvious variation, the main reaction tubes can also be formed entirely of microwave reaction tubes connected in sequence. Example 4

[0055] like Figure 11 As shown, the difference between this embodiment and embodiment 3 is that:

[0056] 1. The external box body 90 is vertically arranged, and the main reaction pipes are vertically arranged along the outer wall of the external box body 90 . There are four main reaction pipes, and the main reaction pipes are still connected by the auxiliary reaction pipes 80 .

[0057] 2. Each secondary reaction pipeline 80 is provided with an inspection port 81 .

[0058] It should be noted that each microwave generator 30 on the main reaction conduit is equipped with a cooling water system 31 and a power supply 32. The arrangement of the cooling water system 31 is common knowledge, and the power supply 32 can be arranged on the side wall or top of the external housing 90. Furthermore, compared with a horizontal arrangement of the main reaction conduit, a vertical arrangement of the main reaction conduit is less prone to material blockage. Example 5

[0059] Example 5 mainly illustrates the innovative arrangement of the microwave generator 30 in Example 2.

[0060] First, the form of the microwave generator 30 is defined. Figure 3 As shown, the long side of the microwave generator 30 is parallel to the end face of the reaction tube 10, which is an E-type; the long side of the microwave generator 30 is perpendicular to the end face of the reaction tube 10, which is an H-type.

[0061] The simulation was performed using COMSOL Multiphysics 6.1, with a total port power of 6 kW, a port frequency of 2.45 GHz, a microwave heating time of 1800 s, and an initial temperature of 20°C. The central plane was defined as the z = 0 plane.

[0062] 1. Compare the differences between E-type and H-type mixed arrangement and pure E-type arrangement

[0063] like Figure 12 As shown, all microwave generators 30 are arranged in the central plane, with an alternating E-type and H-type arrangement on the left and an all-E-type arrangement on the right. It can be seen that the alternating E-type and H-type arrangement achieves a maximum temperature of 20.8°C and an average temperature of 20.2°C; the pure E-type arrangement achieves a maximum temperature of 20.5°C and an average temperature of 20.3°C. Comparing the simulation results, it can be seen that the alternating E-type and H-type arrangement results in faster material heating and higher heating efficiency. The E-type port arrangement achieves a higher average material temperature and better temperature uniformity.

[0064] 2. The difference between pure E-type non-layered arrangement and pure E-type layered arrangement

[0065] like Figure 13 As shown in the figure, with a pure E-type layered arrangement, the upper and lower ports are located at the z = 90.5 mm and z = -70 mm planes, respectively. With a pure E-type unlayered arrangement, the maximum temperature reached 20.5°C, with an average temperature of 20.5°C. With a pure E-type layered arrangement, the maximum temperature reached 22.8°C, with an average temperature of 21.6°C. Comparing the simulation results, it can be seen that the temperature rise rate is significantly improved after the upper and lower ports are layered, and the average temperature is also higher, with better temperature uniformity.

[0066] 3. E-type and H-type mixed layered arrangement

[0067] like Figure 14 As shown, a mixed E-type and H-type layered arrangement is used, with the ports on the upper and lower layers located at the z = 90.5 mm and z = -70 mm planes, respectively. The upper layer is E-type, and the lower layer is H-type. The simulation results show a maximum temperature of 26.967°C and an average temperature of 21.953°C. These results are superior to those of a pure E-type layered arrangement.

[0068] The microwave generator 30 in Example 2 is arranged in this E-type and H-type mixed layered arrangement mode.

Claims

1. A microwave reaction pipeline, comprising a reaction pipeline (10) and a microwave reaction cavity (20) wrapping the reaction pipeline (10), wherein a microwave generator (30) is arranged on the microwave reaction cavity (20), and the reaction pipeline (10) has an input end and an output end, characterized in that: The reaction pipe (10) is a ceramic pipe, and the reaction pipe (10) is provided with connection components independent of the reaction pipe (10) at its input end and output end, and the connection components are located at both ends of the microwave reaction cavity (20).

2. The microwave reaction tube according to claim 1, characterized in that: A wave-transmitting heat-insulating layer (50) is applied on the surface of the reaction pipe (10), and the microwave reaction cavity (20) is located outside the wave-transmitting heat-insulating layer (50).

3. The microwave reaction tube according to claim 1, wherein: The connecting member comprises a flange (41) and a support ring (42), one side of the support ring (42) is fixed to the end of the microwave reaction cavity (20), and the other side of the support ring (42) is the flange (41).

4. The microwave reaction tube according to claim 1, wherein: The connecting member is a flange (41), and a fixing ring (21) for connecting to the flange (41) is provided at each end of the microwave reaction cavity (20).

5. The microwave reaction tube according to claim 1, 3 or 4, characterized in that: The connecting member is provided in two halves, which are combined to form a complete connecting member.

6. The microwave reaction tube according to claim 1, 3 or 4, characterized in that: The microwave reaction cavity (20) is provided in two halves, which are combined to form a complete microwave reaction cavity (20).

7. The microwave reaction tube according to claim 1, wherein: The microwave reaction cavity (20) has a circular or regular polyhedron structure, and at least one group of microwave generators (30) is arranged along the length direction of the microwave reaction cavity (20).

8. The microwave reaction tube according to claim 7, characterized in that: The microwave reaction cavity (20) has a regular hexahedron structure, and two groups of microwave generators (30) are arranged along the length direction of the microwave reaction cavity (20), and each group of microwave generators (30) is arranged in a manner such that one microwave generator (30) is arranged every other face.

9. The microwave reaction tube according to claim 1, wherein: The reaction pipe (10) has an outward-turned portion (11) at its input end and output end, and the outward-turned portion (11) protrudes from the end surface of the connecting component.

10. A microwave tubular continuous flow reactor, characterized in that: The microwave reaction pipes as claimed in claim 1 are connected in sequence to form a main reaction pipe, and sealing gaskets (60) are provided on the contact surfaces of adjacent microwave reaction pipes.

11. The microwave tubular continuous flow reactor according to claim 10, wherein: The cross section of the sealing gasket (60) is in the shape of an I-beam.

12. The microwave tubular continuous flow reactor according to claim 10, wherein: The main reaction pipe is provided with a back-mixing pipe (70), and a back-mixing pipe (70) is provided every at least one microwave reaction pipe. The back-mixing pipe (70) is provided with a back-mixing material input pipe (71) connected to the reacted material.

13. The microwave tubular continuous flow reactor according to claim 10, wherein: The number of the main reaction pipes is at least two, and the main reaction pipes are connected by the auxiliary reaction pipe (80). A sealing gasket (60) is provided at the connection between the main reaction pipe and the auxiliary reaction pipe (80).

14. The microwave tubular continuous flow reactor according to claim 10, wherein: It includes an outer box (90).

15. The microwave tubular continuous flow reactor according to claim 14, wherein: The external box (90) is arranged horizontally, and the main reaction pipes are arranged transversely along the outer wall of the external box (90). The number of the main reaction pipes is at least two, and the main reaction pipes are connected by the auxiliary reaction pipes (80).

16. The microwave tubular continuous flow reactor according to claim 14, wherein: The external box (90) is arranged vertically, and the main reaction pipes are arranged vertically along the outer wall of the external box (90). The number of the main reaction pipes is at least two, and the main reaction pipes are connected by the auxiliary reaction pipes (80).

17. The microwave tubular continuous flow reactor according to claim 16, wherein: The secondary reaction pipeline (80) is provided with an inspection port (81).

18. The microwave tubular continuous flow reactor according to claim 14, wherein: The power supply (32) of the microwave generator (30) is located on the top of the external box (90).

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