Continuous tubular reactor and application thereof

Abstract

The invention provides a continuous tubular reactor and application thereof.The reactor comprises a feeding section, mixing sections, a discharging section and a mixed fluid, at least one mixing section is arranged behind the feeding section of the reactor, an inner cavity of each mixing section is one or more spherical cavities which are communicated end to end, at least one part of the mixed fluid is arranged in one spherical cavity, and at least one part of the mixed fluid is arranged in the other spherical cavity; and a gap for reaction materials to flow is reserved between the mixing body and the inner wall of the spherical cavity. Compared with the scheme that a long and narrow mixing pipe is arranged in the prior art, by introducing a unique mixing structure, the turbulence mixing effect in the pipeline can be enhanced, and the retention time can be prolonged. The tubular reactor can provide continuous reaction, improve the production efficiency and reduce additional operation and personal errors caused by intermittent production.

Description

Technical Field

[0001] The invention relates to the technical field of tubular reactors, in particular to a continuous tubular reactor and its application. The mixer can be used for organic synthesis reactions under high temperature and high pressure conditions, in particular for the reaction of preparing isopropanolamine. Background Art

[0002] Tubular reactors are mainly used for gas phase, liquid phase, gas-liquid phase continuous reaction processes. They have simple structure and are easy to manufacture. They have the characteristics of small volume, large specific surface, and large heat transfer area per unit volume, and are suitable for reactions with large thermal effects.

[0003] However, compared with other reactors, tubular reactors have low mass transfer efficiency and slow reaction rate. At the same time, heat and mass transfer are difficult to control, and temperature or concentration gradients are easily generated, which is not conducive to the stability and selectivity of the reaction. Therefore, there is a need in the art for a tubular inductor that can enhance mixing effect, strengthen mass and heat transfer to solve the above problems. Summary of the invention

[0004] In view of this, the present invention aims to propose a continuous tubular reactor and its application to solve the problems of uneven mixing of reaction materials and low mass transfer and heat transfer efficiency in existing reactors.

[0005] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0006] A continuous tubular reactor comprises a feed section, a mixing section, a discharge section and a fluid-mixing fluid. At least one mixing section is arranged behind the feed section of the reactor. The inner cavity of the mixing section is one or more spherical cavities connected end to end. At least a part of the fluid-mixing fluid is arranged in one of the spherical cavities. The fluid-mixing fluid is spherical, and a gap is left between the fluid-mixing fluid and the inner wall of the spherical cavity for the reaction materials to flow.

[0007] Furthermore, the curvature of the top of the mixing body is smaller than the curvature of the bottom of the mixing body.

[0008] Furthermore, the continuous tubular reactor also includes a fixing component, which is arranged in the spherical cavity, and the mixing fluid is connected to the spherical cavity through the fixing component; preferably, the fixing component includes a fixing rod and a bracket, the mixing fluid is fixed on the fixing rod, the fixing rod is fixed on the bracket, and the bracket is fixed to the inner wall of the mixing section.

[0009] Furthermore, a distance d1 between the top of the fluid mixture and the top of the spherical cavity is 1 / 8-1 / 4 of the radius of the spherical cavity.

[0010] Furthermore, a distance d2 between the inner wall of the spherical cavity and the widest part of the mixed fluid is 1 / 6-1 / 4 of the diameter of the spherical cavity.

[0011] Furthermore, a minimum horizontal distance d3 between the bottom of the inner wall of the spherical cavity and the mixed fluid is 1 / 16-1 / 6 of the diameter of the spherical cavity.

[0012] The continuous tubular reactor also includes a plurality of spoilers, which are arranged on the outer wall of the mixed fluid and are arranged at an angle to the main flow direction of the reaction materials in the reactor; along the main flow direction of the reaction materials, the spoilers are arranged at the widest part of the cross section of the mixed fluid.

[0013] Also includes a plurality of spoilers, wherein the plurality of spoilers are inclined in the same direction, or inclined in different directions;

[0014] The plurality of spoilers are arranged on the outer wall of the mixing body at the same height, or are arranged on the outer wall of the mixing body at different heights.

[0015] The angle between the spoiler and the main flow direction of the material in the reactor is 30-60 degrees.

[0016] The invention also discloses application of the continuous tubular reactor in preparing isopropanolamine.

[0017] Compared with the prior art, the continuous tubular reactor described in the present invention has the following advantages:

[0018] The continuous tubular reactor and its application provided by the invention, compared with the prior art scheme of setting a narrow and long mixing tube, can enhance the turbulent mixing in the pipeline and extend the residence time by introducing a unique mixing structure. Since the reaction is a rapid reaction, the mixing time of the material after entering the tubular reactor can be reduced by introducing the structure described in the application, and the occurrence of side reactions can be reduced. The tubular reactor can provide continuous reaction, improve production efficiency, and reduce the extra operations and human errors caused by intermittent production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 This is a schematic diagram of the overall structure of a continuous tubular reactor according to the present invention;

[0021] Figure 2 It is a perspective structural schematic diagram of a mixing tube of a continuous tubular reactor according to the present invention;

[0022] Figure 3 It is a perspective structural schematic diagram of a mixing tube of a continuous tubular reactor according to the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of a heat exchange unit of a continuous tubular reactor described in the present invention.

[0024] Description of reference numerals:

[0025] 1-feeding section; 2-feeding port; 3-mixing section; 31-fixing rod; 311-bracket; 32-mixing fluid; 33-spoiler; 8-discharging section; 9-heating structure. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0029] The present embodiment provides a continuous tubular reactor, which includes a feeding section 1 at the top and a discharging section 8 at the bottom. At least one mixing section 3 is arranged behind the feeding section 1. The specific number of the mixing sections 3 can be set according to actual conditions. The inner cavity of the mixing section 3 is one or more spherical cavities connected end to end. A mixing fluid 32 is arranged in the spherical cavity. The mixing fluid 32 is spherical. At least a part of the mixing fluid 32 is arranged in a spherical cavity. More specifically, the mixing fluid 32 can be completely arranged in a spherical cavity, or it can be arranged in a spherical cavity. Figure 3 and Figure 4 As shown, a portion of the bottom is disposed in the next adjacent spherical cavity, and a gap is left between the mixed fluid 32 and the inner wall of the spherical cavity for the reaction materials to flow.

[0030] The continuous tubular reactor provided in this embodiment, compared with the prior art scheme of setting a narrow and long mixing tube, can enhance the turbulent mixing in the pipeline and extend the residence time by introducing a unique mixing structure. Since the reaction is a rapid reaction, the mixing time of the material after entering the tubular reactor can be reduced by introducing the structure described in this application, and the occurrence of side reactions can be reduced. The tubular reactor can provide continuous reaction, improve production efficiency, and reduce the additional operations and human errors caused by intermittent production.

[0031] Specifically, in this embodiment, the continuous tubular reactor further includes a fixing assembly, which is disposed in the spherical cavity, and the mixing fluid 32 is connected to the spherical cavity through the fixing assembly. Exemplarily, this embodiment provides a specific structure of a fixing assembly: including a fixing rod 31 and a bracket 311, the mixing fluid 32 is fixed to the fixing rod 31, the fixing rod 31 is fixed to the bracket 311, the bracket 311 is fixed to the inner wall of the mixing section 3, and the shape of the bracket 311 can be selected as needed.

[0032] Of course, in other embodiments, the position of the mixing body 32 can also be fixed by other means. For example, the mixing body 32 can be directly connected to the mixing body 32 by a plurality of support rods fixed to the inner wall of the spherical cavity, so that the mixing body 32 is suspended in the spherical cavity. Alternatively, the fixing rod 31 or the support rod used to position the mixing body 32 can also be set as a telescopic rod to adjust the position of the mixing body 32 in the spherical cavity.

[0033] As a preferred solution, in this embodiment, the curvature of the top of the mixing body 32 is smaller than the curvature of the bottom of the mixing body 32, and the top of the mixing body 32 is more gentle. The purpose of this design is to increase the lateral speed of the material after it contacts the mixing body 32, so that the material can collide with the inner wall of the spherical cavity again under the blocking effect of the top surface of the mixing body 32 and scatter, so as to improve the mixing effect of the material.

[0034] Furthermore, in this embodiment, the widest part of the structure of the mixed body 32 is used as the boundary, the upper half of the boundary is an ellipsoid, and the lower half of the boundary is a cone-like structure. During use, the straight-line distance between the inner wall of the spherical cavity and the outer wall of the mixed body 32 gradually decreases with the flow direction of the fluid, and at the same time, the flow rate of the fluid gradually increases.

[0035] In the continuous tubular reactor provided in this embodiment, the distances between the mixing fluid 32 and the spherical inner cavity of the mixing section 3 can be set as needed. Specifically, the diameter of the spherical cavity is larger than the diameter of the feed section 1. For example, the diameter of the spherical cavity can be 1.5 times the diameter of the feed section 1. Sufficient space should be reserved between the top of the mixing fluid 32 and the top of the spherical inner cavity of the mixing section 3 as the material mixing point; a sufficiently wide gap should also be reserved between the widest part of the mixing fluid 32 and the spherical inner cavity to reserve enough space for the turbulent materials formed by the spoiler 33; the bottom of the inner wall of the spherical cavity and the horizontal plane of the mixing fluid 32 (the horizontal plane is defined as Figure 2 and Figure 3 The minimum straight-line distance is determined by the required material passing speed.

[0036] As a preferred embodiment, in the continuous tubular reactor provided in this embodiment, the distance d1 between the top of the mixing fluid 32 and the top of the spherical cavity is 1 / 8-1 / 4 of the radius of the spherical cavity; the distance d2 between the inner wall of the spherical cavity and the widest part of the mixing fluid 32 is 1 / 6-1 / 4 of the diameter of the spherical cavity; the minimum horizontal distance d3 between the bottom of the inner wall of the spherical cavity and the mixing fluid 32 is 1 / 16-1 / 6 of the diameter of the spherical cavity.

[0037] For example, taking the reactor disposed in the isopropanolamine system as an example, as a preferred embodiment, the distance d1 between the top of the mixing body 32 and the top of the spherical inner cavity of the mixing section 3 is 1 / 4 of the radius of the spherical cavity. The distance d2 between the inner wall of the spherical cavity and the widest part of the mixing body 32 is 1 / 6 of the diameter of the spherical cavity; the minimum horizontal distance d3 between the bottom of the inner wall of the spherical cavity and the mixing body 32 is 1 / 16 of the diameter of the spherical cavity.

[0038] The continuous tubular reactor provided in the present embodiment further comprises a plurality of spoilers 33, which are arranged on the outer wall of the fluid-mixing body 32, and are arranged at an angle with the main flow direction of the reaction materials in the reactor, and the length of the spoilers 33 can be set as required. As a preferred embodiment, along the main flow direction of the reaction materials, the spoilers 33 are arranged at the widest part of the cross section of the fluid-mixing body 32. To further improve the mixing effect of the materials, in the present embodiment, the plurality of spoilers 33 can be tilted in different directions. In other embodiments, the plurality of spoilers 33 can also be arranged on the outer wall of the fluid-mixing body 32 at different heights. Of course, in other embodiments, other settings can also be made as required.

[0039] As a preferred embodiment, in the continuous tubular reactor provided in the present embodiment, the angle between the spoiler 33 and the main flow direction of the material of the reactor is 30-60 degrees. Exemplarily, taking the reactor arranged in the isopropanolamine system as an example, as a preferred embodiment, 8 spoilers 33 can be arranged at the same height of the mixed fluid 32, and the angle between the spoiler 33 and the length direction of the reactor is 45 degrees.

[0040] In the continuous tubular reactor provided in this embodiment, the feed section 1 can be provided with a plurality of feed ports 2 for inputting a variety of materials.

[0041] The continuous tubular reactor provided in this embodiment also includes a temperature sensor for measuring temperature, a flow rate sensor for measuring fluid flow rate, a concentration sensor for measuring fluid concentration, and a pressure sensor for measuring the pressure of the tubular reaction unit, so as to monitor multiple parameters in the reactor. Specifically, a temperature sensor may be provided at the tail end of the feeding section, the front end and the middle of the mixing section, a flow rate sensor may be provided at the feeding section and the discharging section, a concentration sensor may be provided at the middle of the mixing section and the discharging section, and a pressure sensor may be provided at the feeding section, the mixing section, and the discharging section.

[0042] The continuous tubular reactor provided in this embodiment also includes a heating structure 9 for heating the feed section 1. The heating structure 9 is wrapped around the outer periphery of the feed section 1 and is used to adjust the inlet temperature of the reaction material to reach a predetermined temperature. The temperature can also be controlled by wrapping with a heat insulating material. Of course, in other embodiments, a cooling structure can also be provided as required.

[0043] The invention takes the preparation of isopropanolamine by a propylene oxide method and a tubular reactor as an example to introduce the designed tubular reactor. Specific embodiment 1:

[0045] 71.65 wt% of propylene oxide was reacted with liquid ammonia. The molar ratio of ammonia to propylene oxide in the reactant feed was 5:1. The number of mixing sections 3 was 1, and the number of mixed fluids 32 in the mixing section 3 was 2. After the reaction materials passed through the tubular reactor, the propylene oxide conversion rate reached 99.9%, of which the yield of 1-isopropanolamine was 73.7%, the yield of 2-isopropanolamine was 18.2%, and the yield of 3-isopropanolamine was 8.1%. Specific embodiment 2:

[0047] 71.65wt% of propylene oxide was reacted with liquid ammonia. The molar ratio of ammonia to propylene oxide in the reactant feed was 5:1. The number of mixing sections 3 was 2, and the number of mixed fluids 32 in the two mixing sections 3 was 4 and 2 respectively. After the reaction materials passed through the tubular reactor, the propylene oxide conversion rate reached 99.9%, of which the yield of 1-isopropanolamine was 69.8%, the yield of 2-isopropanolamine was 19.4%, and the yield of 3-isopropanolamine was 10.8%.

[0048] Comparative Example 1:

[0049] 71.65wt% of propylene oxide was reacted with liquid ammonia. The molar ratio of ammonia to propylene oxide in the reactant feed was 5:1. The reaction mass directly entered the tubular reactor through the feed port 2. The tubular reactor did not contain a mixing section 3. After the reaction mass passed through the tubular reactor, the propylene oxide conversion rate reached 99%, of which the yield of 1-isopropanolamine was 34.3%, the yield of 2-isopropanolamine was 28.6%, and the yield of 3-isopropanolamine was 37.1%.

[0050] At present, isopropanolamine is mainly prepared by three methods: propylene oxide method, calcium cyanamide method and supercritical fluid method. Among them, the propylene oxide method is the most widely used. This method uses propylene oxide and ammonia water to react under a certain pressure and temperature. At present, my country's use of the propylene oxide method to prepare isopropanolamine faces many problems such as complex steps, intermittent production, difficulty in separating products, and low selectivity.

[0051] The continuous tubular reactor provided in this embodiment can provide a better material mixing effect based on the setting mode, and obtain a better monoisopropanolamine selectivity and yield.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A continuous tubular reactor, characterized in that: The reactor comprises a feed section (1), a mixing section (3), a discharge section (8) and a mixing fluid (32). At least one mixing section (3) is arranged behind the feed section (1) of the reactor. The inner cavity of the mixing section (3) is one or more spherical cavities connected end to end. At least a part of the mixing fluid (32) is arranged in one of the spherical cavities. The mixing fluid (32) is spherical. A gap is left between the mixing fluid (32) and the inner wall of the spherical cavity for the reaction materials to flow.

2. The continuous tubular reactor according to claim 1, characterized in that: The curvature of the top of the mixing body (32) is smaller than the curvature of the bottom of the mixing body (32).

3. The continuous tubular reactor according to claim 1, characterized in that: The mixing fluid (32) is further comprised of a fixing component, which is disposed in the spherical cavity, and the mixing fluid (32) is connected to the spherical cavity via the fixing component; preferably, the fixing component comprises a fixing rod (31) and a bracket (311), the mixing fluid (32) is fixed on the fixing rod (31), the fixing rod (31) is fixed on the bracket (311), and the bracket (311) is fixed on the inner wall of the mixing section (3).

4. The continuous tubular reactor according to claim 1, characterized in that: The distance d1 between the top of the mixing body (32) and the top of the spherical cavity is 1 / 8 to 1 / 4 of the radius of the spherical cavity.

5. The continuous tubular reactor according to claim 1, characterized in that: The distance d2 between the inner wall of the spherical cavity and the widest part of the mixed body (32) is 1 / 6-1 / 4 of the diameter of the spherical cavity.

6. The continuous tubular reactor according to claim 1, characterized in that: The minimum horizontal distance d3 between the bottom of the inner wall of the spherical cavity and the mixing body (32) is 1 / 16-1 / 6 of the diameter of the spherical cavity.

7. The continuous tubular reactor according to claim 1, characterized in that: It also includes a plurality of spoilers (33), which are arranged on the outer wall of the mixed body (32) and are arranged at an angle with the main flow direction of the reaction materials in the reactor; along the main flow direction of the reaction materials, the spoilers (33) are arranged at the widest part of the cross section of the mixed body (32).

8. The continuous tubular reactor according to claim 1, characterized in that: It also includes a plurality of spoilers (33), wherein the plurality of spoilers (33) are inclined in the same direction or in different directions; The plurality of spoilers (33) are arranged on the outer wall of the mixing body (32) at the same height, or are arranged on the outer wall of the mixing body (32) at different heights.

9. The continuous tubular reactor according to claim 7, characterized in that: The angle between the spoiler (33) and the main flow direction of the material in the reactor is 30-60 degrees.

10. Use of the continuous tubular reactor according to any one of claims 1 to 9 in the preparation of isopropanolamine.

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