Vulcanization accelerator microchannel oxidation reactor and oxidation method

Abstract

The vulcanization accelerator microchannel oxidation reactor comprises a shell provided with a cold fluid inlet and a cold fluid outlet, a first reaction chamber, a second reaction chamber and a third reaction chamber are sequentially arranged in the shell from top to bottom, the first reaction chamber is of a thin-plate-shaped structure, the second reaction chamber is of a tubular structure, and the third reaction chamber is of a tubular structure. The third reaction chamber is of a disc type structure, a feeding pipe is arranged on the shell, a solution in the third reaction chamber performs rotational flow motion, a light phase outlet and a heavy phase outlet are formed in the third reaction chamber, and gaps are formed between the first reaction chamber, the second reaction chamber and the third reaction chamber and the inner wall of the shell. The device is good in temperature control effect and suitable for oxidation production of the vulcanization accelerator, the product separation function is synchronously achieved, and the subsequent filtration and separation cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of microchannel reactors, in particular to a vulcanization accelerator microchannel oxidation reactor and an oxidation method. Background Art

[0002] Rubber vulcanization accelerator DM, namely dibenzothiazole disulfide, is an excellent vulcanization accelerator with light yellow needle-shaped crystals. It is slightly soluble in benzene, dichloromethane, carbon tetrachloride, acetone, ethanol, ether, etc. at room temperature, and insoluble in water, ethyl acetate, gasoline and alkali. Its production processes include sodium nitrite method, oxygen oxidation method, hydrogen peroxide method, etc. Among them, the hydrogen peroxide method is the most environmentally friendly method. However, since the synthesis process is an oxidation reaction process, the reaction speed is fast and the heat release is high, it is easy to cause local overheating and increase the by-products. In order to facilitate temperature control, an oxidant is usually added dropwise and a stirring device is used to achieve temperature control, which makes the entire production process time-consuming. The microchannel reactor can accurately control the temperature and is very suitable for the synthesis of temperature-sensitive materials, such as patent 201910319750 .8 discloses a microchannel reactor, which achieves the purpose of precise temperature control by concentrating materials in a reaction tube for mixing reaction. However, a reactor of this structure is not suitable for the production of accelerator DM by the hydrogen peroxide method. The reason is that the synthesized DM has a large density and is insoluble in water and will accumulate in the micro reaction channel. At the same time, solid catalysts are usually added during the hydrogen peroxide synthesis process to speed up the reaction progress. For example, patent 202311761449.5 discloses a high-purity rubber vulcanization accelerator DM and its preparation method. The combined action of the solid catalyst and the product DM will cause the microchannel reactor to become blocked and fail. How to improve the existing microchannel reactor to be suitable for the production of rubber vulcanization accelerator DM is a key difficulty that needs to be overcome in the development of this industry. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a vulcanization accelerator microchannel oxidation reactor and an oxidation method which are suitable for synthesizing accelerator DM by hydrogen peroxide method, have good temperature control effect and avoid blockage of reaction channels.

[0004] One of the purposes of the present invention is to provide a vulcanization accelerator microchannel oxidation reactor, comprising a shell, wherein a first reaction chamber, a second reaction chamber, and a third reaction chamber are sequentially arranged in the shell from top to bottom, wherein the first reaction chamber is a thin plate-shaped structure, the second reaction chamber is a tubular structure, and the third reaction chamber is a disc structure. A feed pipe is arranged on the shell, wherein the feed pipe passes through the shell and communicates with the first reaction chamber, one end of the second reaction chamber is communicated with the first reaction chamber, the bottom end of the second reaction chamber guides the internal solution to flow into the third reaction chamber at a certain angle, and the solution inside the third reaction chamber swirls, and a light phase outlet and a heavy phase outlet are arranged on the third reaction chamber, wherein the light phase outlet communicates with the bottom center of the third reaction chamber, and the heavy phase outlet communicates with the periphery of the third reaction chamber, and gaps are arranged between the first reaction chamber, the second reaction chamber, and the third reaction chamber and the inner wall of the shell, and a cold fluid inlet and a cold fluid outlet are arranged on the shell to realize heat exchange.

[0005] Preferably, there are multiple second reaction chambers, each of which is provided with an internal heat exchange tube, which runs through the second reaction chamber from top to bottom, and both ends of the internal heat exchange tube respectively pass through the second reaction chamber and the shell in sequence and are connected to the external heat exchange fluid.

[0006] Preferably, the second reaction chamber is provided with a plurality of outer baffle rings and a plurality of inner baffle plates, the outer baffle rings are connected to the shell, the inner baffle plates are fixedly connected to the second reaction chamber, the plurality of outer baffle rings and the plurality of inner baffle plates are alternately arranged in an upper and lower manner, and the plurality of outer baffle rings and the plurality of inner baffle plates form, from top to bottom, a kinetic fluid for heat exchange in the second reaction chamber from outside to inside and then from inside to outside.

[0007] Preferably, the third reaction chambers are multiple and stacked up and down, and a first flow guide pipe is arranged between adjacent third reaction chambers, the upper end of the first flow guide pipe is connected to the middle light phase zone of the third reaction chamber, and the lower end of the first flow guide pipe guides the internal solution to flow into the separation zone of the third reaction chamber at a certain angle.

[0008] Preferably, a half-moon ring is provided on the third reaction chamber, the inner ring surface of the half-moon ring is sealingly connected to the third reaction chamber, the outer ring surface of the half-moon ring is in contact with the inner wall of the shell, and the half-moon rings are alternately arranged left and right on the stacked third reaction chamber to guide the heat exchange fluid to make a refractory movement.

[0009] Preferably, the third reaction chamber is an M-shaped structure, and comprises a horizontal section, an inclined section, and a sedimentation section, wherein the horizontal section is a light phase reaction liquid collection area, the inclined section is a centrifugal separation reaction area, and the sedimentation section is a gravity separation area.

[0010] Preferably, the sedimentation section is provided with a separation tube, a material control tube and a spiral auger, the upper end of the separation tube is connected to the middle part of the sedimentation section, the heavy phase outlet is connected to the bottom of the separation tube, the spiral auger is located in the material control tube, the feed end of the material control tube is connected to the bottom of the sedimentation section, and the discharge end of the material control tube is connected to the inclined section of the third reaction chamber of the next layer.

[0011] Preferably, a second flow guide tube is provided at the bottom end of the second reaction chamber, and a diameter of the second flow guide tube is smaller than a diameter of the third reaction chamber.

[0012] Preferably, the feed pipe is a four-way pipe structure, one inlet end of the feed pipe is connected to the crude M sodium salt solution, one inlet end of the feed pipe is connected to hydrogen peroxide, and one inlet end of the feed pipe is connected to the catalyst.

[0013] The second object of the present invention is to provide a vulcanization accelerator microchannel oxidation method, comprising the following steps:

[0014] S1. Mixing crude M sodium salt solution, hydrogen peroxide and catalyst through a feed pipe;

[0015] S2. The mixed reaction liquid is discharged into the first reaction chamber, the first reaction chamber is temperature controlled to react and the reaction liquid is evenly divided and flows into the second reaction chamber;

[0016] S3. The second reaction chamber reacts and the reaction solution is passed into the third reaction chamber in a cyclonic manner;

[0017] S4. The third reaction chamber reacts and separates the product DM into the sedimentation section under centrifugal action, and the remaining light phase is separated into the horizontal section;

[0018] S5.DM in the sedimentation section is discharged through the heavy phase outlet, and the light phase solution is discharged through the light phase outlet

[0019] The invention has the following advantages: a microchannel oxidation reactor and an oxidation method suitable for the reaction synthesis of a vulcanization accelerator DM are proposed; the microchannel reactor not only has a good temperature control effect, but also can effectively separate the organic product DM from the crude M, thereby avoiding the problem of DM blocking the microchannel and reducing the subsequent filtration and separation cost; at the same time, the equipment is also suitable for the use of solid catalysts, thereby ensuring the uniformity of the distribution of the solid catalyst in the microchannel reactor, ensuring the stability of the reaction, and further improving the production efficiency; at the same time, the solid catalyst will not block the microchannel, and the external discharge circulation or replacement is very convenient; the microchannel reaction and separation functions of the aqueous phase, the organic phase and the solid phase are realized as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is a schematic diagram of the overall cross-sectional structure of the present invention;

[0021] Figure 2 The present invention Figure 1 A schematic diagram of the structure viewed from above;

[0022] Figure 3 It is a schematic cross-sectional structure diagram of the third reaction chamber of the present invention.

[0023] In the figure, 1, shell; 2, first reaction chamber; 3, second reaction chamber; 4, third reaction chamber; 5, first guide tube; 6, light phase outlet; 7, heavy phase outlet; 8, feed pipe; 9, cold fluid inlet; 10, cold fluid outlet; 11, internal heat exchange tube; 12, separation tube; 13, material control tube; 14, spiral auger; 15, motor; 16, discharge pipe; 17, half-moon ring; 18, outer baffle ring; 19, inner baffle plate; 20, second guide tube; 21, horizontal section; 22, inclined section; 23, sedimentation section. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0025] like Figure 1-3 As shown, a vulcanization accelerator microchannel oxidation reactor includes a shell 1 of a tank structure, in which a first reaction chamber 2, a second reaction chamber 3, and a third reaction chamber 4 are arranged from top to bottom. The first reaction chamber 2 is a circular thin plate structure, and a cavity with a height of 2-3 mm is arranged inside. The single-layer thin plate structure is conducive to heat exchange between the upper and lower surfaces. The second reaction chamber 3 is a tubular structure. There are multiple second reaction chambers 3. An internal heat exchange tube 11 is installed in each second reaction chamber 3. The internal heat exchange tube 11 passes through the second reaction chamber 3 from top to bottom. Both ends of the internal heat exchange tube 11 pass through the second reaction chamber 3 and the shell 1 in sequence and are connected to the external heat exchange fluid. Since the internal heat exchange tube 11 is installed in each second reaction chamber 3, the temperature in a single reaction chamber can be controlled separately, so that the temperature control is more accurate.

[0026] A plurality of outer baffle rings 18 and a plurality of inner baffle plates 19 are installed on the second reaction chamber 3. The outer baffle rings 18 are connected to the shell 1, and the inner baffle plates 19 are fixedly connected to the second reaction chamber 3. The plurality of outer baffle rings 18 and the plurality of inner baffle plates 19 are alternately arranged at intervals up and down. The plurality of outer baffle rings 18 and the plurality of inner baffle plates 19 form a moving fluid from the outside to the inside and then from the inside to the outside from top to bottom to exchange heat for the second reaction chamber 3. Since the second reaction chamber 3 is multiple and densely distributed, they are wrapped together to form a cylindrical structure, resulting in a higher temperature at the center of the cylinder than at the surroundings. The outer baffle rings 18 and the inner baffle plates 19 can form a baffle motion from the surroundings to the middle and then from the middle to the surroundings, thereby avoiding the formation of a temperature gradient in which the temperature in the middle is higher than that of the surroundings. Compared with the baffles in the traditional heat exchanger, it can form a mixed and rotating motion. The rotation is formed by the Coriolis force, and the heat exchange effect is better.

[0027] The third reaction chamber 4 is a disc-type structure, and the cross section of the third reaction chamber 4 is an M-shaped cavity structure. The third reaction chamber 4 includes a horizontal section 21, an inclined section 22, and a sedimentation section 23. The horizontal section 21 is a light phase reaction liquid collection area, the inclined section 22 is a centrifugal separation reaction area, and the sedimentation section 23 is a gravity separation area. The third reaction chamber 4 is multiple and stacked up and down. A first guide pipe 5 is installed between adjacent third reaction chambers 4. The upper end of the first guide pipe 5 is connected to the middle light phase area of ​​the third reaction chamber 4. The top of the second reaction chamber 3 is connected to the first reaction chamber 2. The second guide pipe 20 is installed at the bottom end of the second reaction chamber 3. The diameter of the second guide pipe 20 is smaller than the diameter of the third reaction chamber 4. After the diameter is reduced, the flow rate of the reaction liquid can be increased. The bottom end of the second guide pipe 20 is connected to the third reaction chamber 4. The lower ends of the first guide pipe 5 and the second guide pipe 20 are connected at an angle of 30 degrees relative to the surface of the inclined section 22 to promote the rotation of the internal reaction liquid. In some embodiments, the lower ends of the first draft tube 5 and the second draft tube 20 can be directly inserted into the inclined section 22 and the internal reaction liquid can be ejected along the tangential direction of the inclined section 22. The formed product DM has a larger density and tends to precipitate downward compared to the crude M sodium salt solution. The rotating reaction liquid in the third reaction chamber 4 can move DM to the surroundings under the action of centrifugal force and fall into the sedimentation section 23. The disc-shaped structure formed by the inclined section 22 can achieve the purpose of gathering the light phase. The planar rotation causes the light phase to run to the surroundings under the action of centrifugal force, resulting in a lack of or no light phase aggregation in the horizontal section. The disc-shaped structure can not only centrifuge the heavy phase, but also gather the light phase to ensure that the light phase continues to flow to the lower layer. The sedimentation section 23 is vertically arranged below the disc structure, which can reduce the influence of the inclined section 22 on the rotation and centrifugation of the sedimentation section 23, so that the solution in the sedimentation section 23 is slow or static, which is conducive to the separation of the heavy phase and the light phase.

[0028] A feed pipe 8 is installed on the top of the shell 1, and the feed pipe 8 passes through the shell 1 and is connected to the first reaction chamber 2. A heavy phase outlet 7 is installed at the bottom of the sedimentation section 23 of the third reaction chamber 4, and a light phase outlet 6 is installed at the center of the horizontal section 21 of the third reaction chamber 4 located at the bottom. Gaps are set between the first reaction chamber 2, the second reaction chamber 3, and the third reaction chamber 4 and the inner wall of the shell 1. A cold fluid inlet 9 is installed on the top of the shell 1, and a cold fluid outlet 10 is installed at the bottom of the shell 1, that is, the three reaction chambers are all wrapped in the heat exchange fluid.

[0029] In some embodiments, the space between the stacked third reaction chambers 4 is narrow, and the heat exchange fluid is not easy to move quickly, which seriously affects the heat exchange effect. A half-moon ring 17 is installed on the third reaction chamber 4. The inner ring surface of the half-moon ring 17 is sealed and connected to the third reaction chamber 4, and the outer ring surface of the half-moon ring 17 is connected to the inner wall of the shell 1. The half-moon rings 17 are alternately arranged on the left and right sides of the stacked third reaction chambers 4, that is, a baffle structure similar to a heat exchanger is formed between the half-moon rings 17 and the third reaction chambers 4. The half-moon rings 17 can guide the heat exchange fluid to do baffle movement to accelerate the heat exchange between the third reaction chambers 4.

[0030] In some embodiments, if a solid catalyst is added during the DM production process, it is necessary to consider the impact of the solid catalyst on the microchannel reactor. First, the feed pipe 8 is set to a four-way pipe structure, one inlet end of the feed pipe 8 is connected to the crude M sodium salt solution, one inlet end of the feed pipe 8 is connected to hydrogen peroxide, and one inlet end of the feed pipe 8 is connected to the catalyst. The feed pipe 8 plays the role of mixing the reaction raw materials to avoid the problem that the raw material pipelines are directly connected to the first reaction chamber 2, causing the raw materials to be discharged into the second reaction chamber 3 separately, resulting in uneven reaction between the second reaction chambers 3.

[0031] A separation tube 12, a material control tube 13, and a spiral auger 14 are installed on the sedimentation section 23. A motor 15 is installed outside the shell 1. The motor 15 is a servo motor that can accurately control the speed. The upper end of the separation tube 12 is connected to the middle part of the sedimentation section 23. A filter screen is installed at the connection between the separation tube 12 and the sedimentation section 23 to prevent the solid catalyst from entering the separation tube 12. The heavy phase outlet 7 is connected to the bottom of the separation tube 12. The spiral auger 14 is located in the material control tube 13. The motor 15 drives the spiral auger 14 to rotate slowly. The feed end of the material control tube 13 is connected to the bottom of the sedimentation section 23. The discharge end of the material control tube 13 is installed with a discharge pipe 16. The discharge end of the discharge pipe 16 is connected to the inclined section 22 of the third reaction chamber 4 of the next layer. The discharge pipe 16 is installed at the bottom to directly pass through the shell 1 for external discharge. The density of the solid catalyst is greater than that of DM and greater than that of the coarse M. When the three are in a static state, the solid catalyst is located at the bottom, followed by DM, and the coarse M is at the top. The setting of the separation tube 12 can separate and discharge the DM in the middle of the sedimentation section 23, and the solid catalyst at the bottom is controlled by the material control pipe 13 to control the feeding. Only installing the material control pipe 13 can also discharge the solid catalyst in the upper layer into the lower layer, but the discharge speed cannot be controlled. The spiral auger 14 can form a spiral channel. When the solid catalyst is filled inside, it can provide a large pressure drop and block the material control pipe 13 to prevent the upper layer DM or coarse M from flowing into the bottom. At this time, the spiral auger 14 plays a role similar to a valve blockage. At the same time, the motor 15 is controlled to rotate slowly, and the solid catalyst can also be discharged to the lower layer, ensuring the smooth operation of the equipment.

[0032] A vulcanization accelerator microchannel oxidation method comprises the following steps:

[0033] S1. The crude M sodium salt solution, hydrogen peroxide, and solid catalyst are mixed through a feed pipe 8;

[0034] S2. The mixed reaction liquid is discharged into the first reaction chamber 2, the first reaction chamber 2 is temperature controlled for reaction and the reaction liquid is evenly divided and flows into the second reaction chamber 3;

[0035] S3. The second reaction chamber 3 reacts and the reaction liquid is passed into the third reaction chamber 4 in a cyclonic manner;

[0036] S4. The third reaction chamber 4 reacts and separates the product DM into the sedimentation section 23 under centrifugal action, and the remaining light phase is separated into the horizontal section 21;

[0037] S5. The DM in the settling section 23 is discharged into the separation tube 12 for secondary settling and discharged through the heavy phase outlet 7, the light phase solution is discharged through the light phase outlet 6, and the solid catalyst is discharged through the material control tube 13.

[0038] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vulcanization accelerator microchannel oxidation reactor, characterized in that: The invention comprises a shell (1), wherein a first reaction chamber (2), a second reaction chamber (3), and a third reaction chamber (4) are arranged in sequence from top to bottom in the shell (1), wherein the first reaction chamber (2) is a thin plate-shaped structure, the second reaction chamber (3) is a tubular structure, and the third reaction chamber (4) is a disc-shaped structure, wherein a feed pipe (8) is arranged on the shell (1), wherein the feed pipe (8) passes through the shell (1) and is connected to the first reaction chamber (2), wherein one end of the second reaction chamber (3) is connected to the first reaction chamber (2), and the bottom end of the second reaction chamber (3) guides the internal solution to flow in a The liquid flows into the third reaction chamber (4) at a certain angle, and the solution in the third reaction chamber (4) swirls. The third reaction chamber (4) is provided with a light phase outlet (6) and a heavy phase outlet (7). The light phase outlet (6) is connected to the bottom center of the third reaction chamber (4), and the heavy phase outlet (7) is connected to the periphery of the third reaction chamber (4). Gaps are provided between the first reaction chamber (2), the second reaction chamber (3), and the third reaction chamber (4) and the inner wall of the shell (1). The shell (1) is provided with a cold fluid inlet (9) and a cold fluid outlet (10) to achieve heat exchange.

2. A vulcanization accelerator microchannel oxidation reactor according to claim 1, characterized in that: There are a plurality of second reaction chambers (3), each of which is provided with an internal heat exchange tube (11), the internal heat exchange tube (11) passing through the second reaction chamber (3) from top to bottom, and the two ends of the internal heat exchange tube (11) respectively pass through the second reaction chamber (3) and the shell (1) in sequence and are connected to an external heat exchange fluid.

3. A vulcanization accelerator microchannel oxidation reactor according to claim 2, characterized in that: The second reaction chamber (3) is provided with a plurality of outer baffle rings (18) and a plurality of inner baffle plates (19); the outer baffle rings (18) are internally connected to the shell (1); the inner baffle plates (19) are fixedly connected to the second reaction chamber (3); the plurality of outer baffle rings (18) and the plurality of inner baffle plates (19) are alternately arranged at intervals up and down; the plurality of outer baffle rings (18) and the plurality of inner baffle plates (19) sequentially form, from top to bottom, a kinetic fluid for exchanging heat with the second reaction chamber (3) from outside to inside and then from inside to outside.

4. A vulcanization accelerator microchannel oxidation reactor according to any one of claims 1 to 3, characterized in that: The third reaction chamber (4) is multiple and stacked up and down, and a first flow guide tube (5) is arranged between adjacent third reaction chambers (4), the upper end of the first flow guide tube (5) is connected to the middle light phase zone of the third reaction chamber (4), and the lower end of the first flow guide tube (5) guides the internal solution to flow into the separation zone of the third reaction chamber (4) at a certain angle.

5. A vulcanization accelerator microchannel oxidation reactor according to claim 4, characterized in that: A half-moon ring (17) is arranged on the third reaction chamber (4); the inner ring surface of the half-moon ring (17) is sealingly connected to the third reaction chamber (4); the outer ring surface of the half-moon ring (17) is in contact with the inner wall of the shell (1); the half-moon ring (17) is alternately arranged on the left and right sides of the stacked third reaction chamber (4) to guide the heat exchange fluid to perform a baffle movement.

6. A vulcanization accelerator microchannel oxidation reactor according to claim 5, characterized in that: The third reaction chamber (4) is an M-shaped structure, and comprises a horizontal section (21), an inclined section (22), and a sedimentation section (23), wherein the horizontal section (21) is a light phase reaction liquid collection area, the inclined section (22) is a centrifugal separation reaction area, and the sedimentation section (23) is a gravity separation area.

7. A vulcanization accelerator microchannel oxidation reactor according to claim 6, characterized in that: The sedimentation section (23) is provided with a separation tube (12), a material control tube (13), and a spiral auger (14); the upper end of the separation tube (12) is connected to the middle part of the sedimentation section (23); the heavy phase outlet (7) is connected to the bottom of the separation tube (12); the spiral auger (14) is located in the material control tube (13); the feed end of the material control tube (13) is connected to the bottom of the sedimentation section (23); and the discharge end of the material control tube (13) is connected to the inclined section (22) of the third reaction chamber (4) of the next layer.

8. A vulcanization accelerator microchannel oxidation reactor according to claim 7, characterized in that: A second flow guide tube (20) is provided at the bottom end of the second reaction chamber (3), and the diameter of the second flow guide tube (20) is smaller than the diameter of the third reaction chamber (4).

9. A vulcanization accelerator microchannel oxidation reactor according to claim 8, characterized in that: The feed pipe (8) is a four-way pipe structure, one inlet end of the feed pipe (8) is connected to a crude M sodium salt solution, one inlet end of the feed pipe (8) is connected to hydrogen peroxide, and one inlet end of the feed pipe (8) is connected to a catalyst.

10. A vulcanization accelerator microchannel oxidation method according to claim 1, characterized in that: The following steps are included: S1. Mixing the crude sodium salt solution of M, hydrogen peroxide and the catalyst through a feed pipe (8); S2. The mixed reaction liquid is discharged into the first reaction chamber (2), the first reaction chamber (2) is temperature controlled to react and the reaction liquid is evenly divided and flows into the second reaction chamber (3); S3. The second reaction chamber (3) reacts and the reaction solution is passed into the third reaction chamber (4) in a cyclonic manner; S4. The third reaction chamber (4) reacts and separates the product DM into the sedimentation section (23) under centrifugal action, and the remaining light phase is separated into the horizontal section (21); S5. The DM in the settling section (23) is discharged through the heavy phase outlet (7), and the light phase solution is discharged through the light phase outlet (6).

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