Gas-liquid mixing device and gas-liquid reaction system

Abstract

This utility model discloses a gas-liquid mixing device and a gas-liquid reaction system, belonging to the field of chemical equipment technology. The gas-liquid mixing device includes a liquid phase distribution pipe and a gas phase distribution pipe. The liquid phase distribution pipe has at least one liquid inlet and several liquid outlets, each connected to a gas-liquid mixing pipe. The gas phase distribution pipe has at least one gas inlet and several gas outlets, each connected to a gas-liquid mixing pipe. The liquid outlets and gas-liquid mixing pipes are arranged in a one-to-one correspondence. The outlet end of the liquid outlet narrows radially inward to form a constricted section, which is inserted into the inlet of the gas-liquid mixing pipe, forming an annular gas inlet channel. This application has a simple structure, high reaction efficiency, and good reaction performance even in large reactors.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment technology, specifically to a gas-liquid mixing device and a gas-liquid reaction system. Background Technology

[0002] In large-scale industrial production, bubble column reactors are commonly used for gas-liquid reactions. The typical reaction method involves adding liquid reactants to the reactor, then transferring gaseous reactants to the liquid reactants from the bottom of the reactor. The rising buoyancy of the bubbles creates a stirring effect, ensuring thorough mixing of the gas and liquid phases. For example, Chinese patent CN1528732A discloses a bubble column oxidation reactor for the production of terephthalic acid, employing a straight-cylinder bubble column oxidation reactor without stirring, achieving gas-liquid mixing and reaction. However, this method has the disadvantage of producing relatively large-diameter bubbles from the gaseous material, resulting in a small effective gas-liquid contact area and low reaction efficiency.

[0003] To improve reaction efficiency and reduce impurity generation, existing methods typically modify the structure and method of bubbling reactors. For example, Chinese patent CN106554298A discloses a method for preparing ethylbenzene hydroperoxide by oxidizing ethylbenzene. The reactor is divided into 4 to 20 bubbling reaction zones by constructing a tray. Each or every two bubbling reaction zones is equipped with a gas inlet and a gas distributor at the bottom, thereby achieving stepwise temperature control of each bubbling reaction zone.

[0004] However, the problem with the existing technology is that the bubble diameter of the gaseous material is still relatively large, resulting in poor oxygen utilization. On the other hand, reducing the bubble diameter is not conducive to the uniform dispersion of the gas phase in the liquid phase, especially in large reactors with a volume greater than 100 cubic meters. Utility Model Content

[0005] To solve the above problems, this utility model provides a gas-liquid mixing device and a gas-liquid reaction system.

[0006] The technical solution adopted in this utility model is:

[0007] A gas-liquid mixing device includes a liquid phase distribution pipe and a gas phase distribution pipe. The liquid phase distribution pipe has at least one liquid inlet and several liquid outlets, each of which is connected to a liquid outlet pipe. The gas phase distribution pipe has at least one air inlet and several air outlets, each of which is connected to a gas-liquid mixing pipe. The liquid outlet pipes and the gas-liquid mixing pipes are arranged in a one-to-one correspondence. The outlet end of the liquid outlet pipe is radially constricted inward to form a constricted section. The constricted section of the liquid outlet pipe is inserted into the inlet of the gas-liquid mixing pipe, and an annular air inlet channel is formed between the liquid outlet pipe and the gas-liquid mixing pipe.

[0008] The reduction of bubble diameter and the uniform distribution of gas-liquid mixture within the reactor cross-sectional area are achieved through the corresponding arrangement of the liquid outlet pipe and the gas-liquid mixing pipe, as well as the distribution method of the gas-liquid mixing pipe. In operation, gaseous material enters the gas phase distribution pipe through the gas inlet, and liquid material enters the liquid phase distribution pipe through the liquid inlet. After being uniformly distributed in the liquid phase distribution pipe, the liquid material enters the liquid outlet pipe and flows out at high speed from the constricted section into the gas-liquid mixing pipe. A negative pressure is formed near the inlet of the gas-liquid mixing pipe, generating a self-drawing force that draws the gaseous material from the gas phase distribution pipe into the gas-liquid mixing pipe, thus achieving gas-liquid mixing. During the drawing-in process, the high-speed flowing liquid phase exerts shearing and impact forces on the self-drawn gas phase, thereby breaking up the gas phase and forming microbubbles with a diameter of less than 1 mm.

[0009] The number of gas-liquid mixing pipes is determined based on the physicochemical properties of the reactants and the inner diameter of the applicable reactor, with the aim of achieving a uniform distribution of the gas-liquid mixture across the cross-section of the reaction tower.

[0010] Furthermore, a flow mixing element is provided in the gas-liquid mixing tube. The cutting action of the flow mixing element further reduces the size of the bubbles and improves the gas-liquid mixing effect.

[0011] Furthermore, the mixing element is a corrugated plate or staggered baffles. It offers high dispersion, low non-uniformity coefficient, and is suitable for gas-liquid mixing.

[0012] Furthermore, the outlet end of the gas-liquid mixing tube is either open or closed by an orifice plate. An open outlet helps increase the diffusion range of the gas-liquid mixture, while an orifice plate helps reduce bubble size.

[0013] Furthermore, the length-to-diameter ratio of the gas-liquid mixing tube is 5–60. Too small a ratio is not conducive to the formation of microbubbles, while too large a ratio increases the risk of side reactions.

[0014] Furthermore, the liquid phase distribution pipe and the gas phase distribution pipe can be straight pipes or annular pipes, with the liquid outlet pipe vertically passing through the gas phase distribution pipe and inserted into the inlet of the gas-liquid mixing pipe. This facilitates the stability of the negative pressure near the inlet of the gas-liquid mixing pipe, ensuring the self-absorption effect of the gas phase.

[0015] Furthermore, both the liquid phase distribution pipe and the gas phase distribution pipe are annular pipes. This facilitates the uniform distribution of the gas-liquid mixture within the reactor's cross-sectional area.

[0016] Furthermore, the centerline of the liquid outlet pipe coincides with that of the gas-liquid mixing pipe. This helps reduce resistance and ensures a uniform distribution of the gas phase within the inlet channel, thereby improving the microbubble generation effect.

[0017] Furthermore, the diameter of the constricted section of the liquid outlet pipe is smaller than the diameter of the gas-liquid mixing pipe, and greater than or equal to 1 / 3 of the diameter of the gas-liquid mixing pipe.

[0018] The constricted section of the liquid outlet pipe forms an annular air inlet channel with the gas-liquid mixing pipe. The size of the air inlet channel affects the stability of the gas flow rate, which in turn affects the formation of microbubbles. If the air inlet channel is too large, the gas cannot be drawn into the gas-liquid mixing pipe by its own suction force, resulting in poor microbubble generation. If the air inlet channel is too small, it will reduce the gas flow rate, causing a decrease in the effective mixing volume per unit.

[0019] A gas-liquid reaction system includes a reactor body, a circulating pump, and any one of the above-mentioned gas-liquid mixing devices; the gas-liquid mixing device is located inside the reactor body, and the liquid inlet and gas inlet extend to the outside of the reactor shell, and a spray device is provided above the gas-liquid mixing device; the circulating pump is located outside the reactor body and is connected to the bottom of the reactor body and the spray device through a circulating pipe.

[0020] During use, liquid and gaseous materials enter the gas-liquid mixing device through the liquid inlet and gas inlet. After the bubbles are broken and fully mixed, the gas-liquid mixture containing microbubbles enters the interior of the reactor body from the gas-liquid mixing pipe outlet. Under the action of the circulating pump and spray device, it circulates inside and outside the reactor body, further improving the mixing effect and reaction efficiency.

[0021] Furthermore, the liquid phase distribution pipe is located above the gas phase distribution pipe, and the outlet of the gas-liquid mixing pipe faces downward; or the liquid phase distribution pipe is located below the gas phase distribution pipe, and the outlet of the gas-liquid mixing pipe faces upward.

[0022] Furthermore, an exhaust port is provided at the top of the reactor body to allow gaseous substances to be discharged in a timely manner.

[0023] The beneficial effects of this utility model are:

[0024] 1. By utilizing the constriction effect of the liquid outlet pipe, the liquid phase material is ejected at high speed from the constriction opening of the liquid outlet pipe to form a jet, creating a negative pressure suction at the inlet of the gas-liquid mixing pipe, which draws in the gas phase material; the high-speed flowing liquid phase generates shearing and impact forces on the self-drawn gas phase, thereby breaking up the gas phase and forming microbubbles; thus increasing the gas-liquid contact area.

[0025] 2. By distributing the gas-liquid mixing pipes, the coverage of microbubbles in the reactor body is improved, which is beneficial to improving the uniformity of gas phase dispersion in liquid phase.

[0026] 3. This application has a simple structure, high reaction efficiency, and good reaction effect in large reactors. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the gas-liquid mixing device of this application.

[0028] Figure 2 This is a schematic diagram of the annular air intake channel structure.

[0029] Figure 3 The structure connecting the liquid outlet pipe and the gas-liquid mixing pipe Figure 1 .

[0030] Figure 4 The structure connecting the liquid outlet pipe and the gas-liquid mixing pipe Figure 2 .

[0031] Figure 5 The structure connecting the liquid outlet pipe and the gas-liquid mixing pipe Figure 3 .

[0032] Figure 6 The structure connecting the liquid outlet pipe and the gas-liquid mixing pipe Figure 4 .

[0033] Figure 7 This is a structural diagram of the gas-liquid reaction system of this application. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below in conjunction with the accompanying drawings and preferred embodiments.

[0035] See Figures 1-6 This embodiment provides a gas-liquid mixing device 100, including a liquid phase distribution pipe 11 and a gas phase distribution pipe 21. The liquid phase distribution pipe has a liquid inlet 111 and several liquid outlets, each of which is connected to an outlet pipe 12. The gas phase distribution pipe 21 has an air inlet 211 and several air outlets, each of which is connected to a gas-liquid mixing pipe 22. The liquid phase distribution pipe 11 is arranged parallel to the gas phase distribution pipe 21 directly above it. The center lines of the outlet pipes 12 and the gas-liquid mixing pipe 22 coincide, are concentric and coaxial. The lower ends of the outlet pipes 12 are vertically inserted into the air outlets of the gas phase distribution pipe 21. The outlet ends of the outlet pipes 12 are radially constricted inward to form a constriction. The constricted section of the outlet pipe 12 is inserted into the inlet of the gas-liquid mixing pipe 22, and an annular air inlet channel 101 is formed between the constricted section 121 and the gas-liquid mixing pipe.

[0036] In this embodiment, both the liquid phase distribution pipe 11 and the gas phase distribution pipe 21 are annular pipes, and 25 liquid outlet pipes 12 and gas-liquid mixing pipes 22 are arranged in a ring shape along the circumference of each pipe.

[0037] In other embodiments, the liquid phase distribution pipe 11 and the gas phase distribution pipe 21 can both be straight pipes, and the liquid outlet pipe 12 and the gas-liquid mixing pipe 22 can both be arranged in a straight line in parallel. To improve the uniform distribution of the gas-liquid mixture within the cross-section of the reaction tower, multiple parallel-connected straight liquid phase distribution pipes 11 and gas phase distribution pipes 21 can also be provided. The straight liquid phase distribution pipe 11 and gas phase distribution pipe 21 are open at both ends, or open at one end and closed at the other end by a blind flange. The open ends form two feed inlets, which helps to stabilize the material flow rate and ensure uniform feed distribution.

[0038] In other embodiments, the air inlet and liquid inlet of the annular liquid phase distribution pipe 11 and gas phase distribution pipe 21 can also be set to >1, such as 2-10 or 4-8.

[0039] In this embodiment, the large-diameter section of the liquid outlet pipe 12 and the constricted section 121 are connected by a conical section to improve the jetting effect of the liquid phase.

[0040] In this embodiment, the length-to-diameter ratio of the gas-liquid mixing pipe 22 is 5.0, and the diameter D1 of the constricted section 121 of the liquid outlet pipe is equal to 1 / 3 of the diameter D2 of the gas-liquid mixing pipe 22. Specifically, the length of the gas-liquid mixing pipe 22 is 90 mm, the diameter of the gas-liquid mixing pipe 22 is 18 mm, and the diameter of the constricted section 121 of the liquid outlet pipe is 6 mm. The diameter of the liquid phase distribution pipe 11 is 700 mm, and the diameter of the gas phase distribution pipe 21 is 700 mm.

[0041] In other embodiments, the length-to-diameter ratio of the gas-liquid mixing tube 22 is selected in the range of 5 to 60 (inclusive of the two end values); the diameter of the constricted section 121 is selected in the range of 1 / 3D2 to D2 (excluding the maximum value).

[0042] See Figure 3 In this embodiment, the outlet end of the gas-liquid mixing pipe 22 is open, the liquid outlet pipe 12 is inserted vertically through the gas phase distribution pipe 21 into the inlet of the gas-liquid mixing pipe 22, and the constricted section 121 of the liquid outlet pipe 12 is inserted into the inlet end of the gas-liquid mixing pipe 22 for a certain length to ensure that microbubbles are generated and have a suitable diffusion range.

[0043] See Figure 4 In another embodiment of this application, the outlet end of the gas-liquid mixing pipe 22 is sealed by an orifice plate 23, which is a perforated plate. The gas-liquid mixing pipe 22 is also provided with a through hole to further reduce the bubble size.

[0044] See Figure 5In another embodiment of this application, the constricted section 121 of the outlet pipe 12 is inserted only into the inlet of the gas-liquid mixing pipe 22; and the gas-liquid mixing pipe 22 is provided with a mixing element 24. In this embodiment, the mixing element 24 is a staggered baffle. In other embodiments, the mixing element 24 may also be a plurality of corrugated plates arranged axially, with a plurality of flow channels formed between the corrugated plates.

[0045] See Figure 6 In another embodiment of this application, the outlet end of the gas-liquid mixing tube 22 is sealed by a tube sheet 25. The tube sheet 25 is U-shaped and perforated, and the end of the gas-liquid mixing tube 22 protrudes radially outward to form a connection portion connecting to the tube sheet 25. The outer diameter of the tube sheet 25 is larger than the outer diameter of the gas-liquid mixing tube 22, and the gas phase is further broken up within the tube sheet 25.

[0046] See Figure 7 This embodiment provides a gas-liquid reaction system, including a vertical reaction tower 110 with a volume of 130 cubic meters, a circulating pump 130, and a gas-liquid mixing device 100. The gas-liquid mixing device 100 is located at the lower part of the reaction tower 110, and the liquid inlet and gas inlet of the gas-liquid mixing device 100 extend to the outside of the reaction tower. A spray device 120 is provided above the gas-liquid mixing device 100. The circulating pump 130 is located outside the reactor body and is connected to the bottom of the reaction tower 110 and the spray device 120 through a circulating pipe.

[0047] In this embodiment, the outlet of the gas-liquid mixing pipe of the gas-liquid mixing device 100 is vertically downward; in other embodiments, the outlet of the gas-liquid mixing pipe may also be vertically upward, or at a certain angle to the axis of the reaction tower.

[0048] In this embodiment, there is one gas-liquid mixing device 100. In other embodiments, in order to achieve efficient distribution of the gas-liquid mixture within the main body of the vertical reaction tower, there can be multiple gas-liquid mixing devices, which can be set on the same horizontal plane or on different horizontal planes.

[0049] When the above reaction system is in use, the liquid phase material enters the gas-liquid mixing device through the liquid inlet, and the gas phase material enters the gas-liquid mixing device through the gas inlet. The gas-liquid mixture containing microbubbles flows out from the gas-liquid mixing pipe of the gas-liquid mixing device and is released into the reaction tower. Then, it is pumped by the circulation pump 130 to the spray device 120 for external circulation.

[0050] Practice has proven that when the gas-liquid reaction system of this embodiment is used to prepare cumene hydrogen peroxide by reacting cumene with oxygen, under the same reaction conditions, i.e. the same reaction tower structure size, the same external circulation method, and the same reaction pressure, reaction temperature, and reaction time, compared with the traditional bubbling method, this embodiment can obtain a gas-liquid mixture with a bubble diameter of <500μm and a more uniform gas phase dispersion, thereby increasing the oxygen utilization rate to over 95%.

[0051] The reaction system of this invention is suitable for reactions involving both gas and liquid phases, such as oxidation reactions involving oxygen and reduction reactions involving hydrogen. Before use, a certain amount of liquid material can be pre-injected into the vertical reaction tower, or it can be left uninjected. When the reaction product is an unstable substance such as a peroxide, it is preferable to first inject a certain amount of liquid material into the reaction tower.

[0052] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications are also within the protection scope of the present utility model.

Claims

1. A gas-liquid mixing device, characterized in that, It includes a liquid phase distribution pipe and a gas phase distribution pipe. The liquid phase distribution pipe has at least one liquid inlet and several liquid outlets, and each liquid outlet is connected to a liquid outlet pipe. The gas phase distribution pipe has at least one gas inlet and several gas outlets, and each gas outlet is connected to a gas-liquid mixing pipe. The liquid outlet pipe and the gas-liquid mixing pipe are arranged in a one-to-one correspondence. The outlet end of the liquid outlet pipe is radially constricted inward to form a constriction. The constricted section of the liquid outlet pipe is inserted into the inlet of the gas-liquid mixing pipe, and an annular gas inlet channel is formed between the liquid outlet pipe and the gas-liquid mixing pipe.

2. The gas-liquid mixing device according to claim 1, characterized in that, The gas-liquid mixing pipe is equipped with a flow mixing element.

3. The gas-liquid mixing device according to claim 2, characterized in that, The mixing element is a corrugated plate or staggered baffles.

4. The gas-liquid mixing device according to claim 1, characterized in that, The outlet end of the gas-liquid mixing pipe is either open or sealed by an orifice plate.

5. The gas-liquid mixing device according to claim 1, characterized in that, The length-to-diameter ratio of the gas-liquid mixing tube is 5 to 60.

6. The gas-liquid mixing device according to claim 1, characterized in that, The liquid phase distribution pipe and the gas phase distribution pipe are straight pipes or ring pipes. The liquid outlet pipe passes through the gas phase distribution pipe vertically and is inserted into the inlet of the gas-liquid mixing pipe.

7. A gas-liquid mixing device according to claim 6, characterized in that, The center lines of the liquid outlet pipe and the gas-liquid mixing pipe coincide.

8. The gas-liquid mixing device according to claim 1, characterized in that, The diameter of the constricted section of the liquid outlet pipe is smaller than the diameter of the gas-liquid mixing pipe, but greater than or equal to 1 / 3 of the diameter of the gas-liquid mixing pipe.

9. A gas-liquid reaction system, characterized in that, The reactor includes a reactor body, a circulating pump, and a gas-liquid mixing device as described in any one of claims 1-8; the gas-liquid mixing device is located inside the reactor body, with the liquid inlet and gas inlet extending to the outside of the reactor shell, and a spray device is provided above the gas-liquid mixing device; the circulating pump is located outside the reactor body and is connected to the bottom of the reactor body and the spray device through a circulating pipe.

10. A gas-liquid reaction system according to claim 9, characterized in that, The liquid phase distribution pipe is located above the gas phase distribution pipe, and the outlet of the gas-liquid mixing pipe faces downward; or the liquid phase distribution pipe is located below the gas phase distribution pipe, and the outlet of the gas-liquid mixing pipe faces upward.

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