High-efficiency gas-liquid mass transfer device and application thereof

Abstract

The application belongs to the field of polymer hydrogenation and polymer wet stripping, and discloses a high-efficiency gas-liquid mass transfer device and application thereof. The device comprises a kettle body, a stirrer and a hollow baffle. The stirrer is arranged in the kettle body. The hollow baffle is arranged on the side wall of the kettle body, and the hollow baffle is provided with a gas outlet. The kettle body is provided with a liquid phase feeding port, a liquid phase discharging port, a gas phase feeding port and a gas phase discharging port. The liquid phase feeding port is arranged on the top and / or the side wall of the kettle body. The liquid phase discharging port is arranged on the lower part of the kettle body. The gas phase feeding port is arranged on the top and / or the side wall of the kettle body, and the gas phase feeding port is communicated with the hollow baffle through an inner insertion pipe. The gas phase discharging port is arranged on the top of the kettle body. The device can promote the full mixing of materials, improve the gas-liquid mass transfer rate and reduce the stirring power.

Description

Technical Field

[0001] This invention belongs to the fields of polymer hydrogenation and polymer wet stripping, and more specifically, relates to a high-efficiency gas-liquid mass transfer device and its application. Background Technology

[0002] In the polymer field, hydrogenation processes of unsaturated polymers, as well as reactions and stripping of polymer solutions, typically employ stirred tank reactors. The polymer solution and chemicals, such as catalysts, are thoroughly mixed under stirring. Gases are dispersed by stirring, forming numerous bubbles. Mass transfer and / or reactions occur on the bubble surfaces to generate the target product. The system within the reactor can be either a gas-liquid-solid heterogeneous system or a gas-liquid homogeneous system. The uniformity of the distribution of additives and reaction media in the solution, and the presence of dead zones, all affect the mass transfer rate, reaction rate, and yield of the entire process. Furthermore, for gas-liquid mass transfer and / or reaction processes, the gas-phase mass transfer rate and the amount of dissolved gas in the solution are also key factors influencing mass transfer.

[0003] Under current technology, to ensure thorough mixing of chemicals such as catalysts and additives and reduce dead zones, the common method is to increase the stirring speed to improve the circulation flow of the agitator, which also helps to disperse air bubbles. Simultaneously, optimizing the agitator diameter, blade structure, and number of impeller layers further enhances the stirring effect, significantly increasing the stirring power. To improve gas solubility, the pressure of the reactor needs to be increased, while ensuring gas replenishment during the reaction process. Furthermore, for reaction systems with high viscosity, the reaction temperature is increased where possible to promote material dispersion, reduce viscosity, and improve mass and heat transfer rates. However, high-temperature and high-pressure reaction conditions place high demands on process control and equipment, resulting in high operating energy consumption. Complex agitator structures also lead to high investment costs. For high-viscosity polymer fluids, excessively high agitator speeds can easily create channeling, resulting in dead zones around the agitator. For complex agitators, significant blockage can easily occur at the stirring points.

[0004] CN113694837A discloses a design method for a stirring device, employing a hollow stirring shaft and a gas distributor with openings. A gas inlet is provided at the upper part of the hollow stirring shaft to allow gas to enter its interior. The gas distributor is arranged around the hollow stirring shaft and maintains communication with the internal space of the shaft to increase the gas-liquid phase contact area between the gas and the adhesive. However, because the stirring shaft is constantly rotating, sealing the connection between the gas inlet and the stirring shaft is difficult to achieve; the hollow stirring shaft reduces its strength and limits the stirring power; furthermore, the gas ejected from the rotating stirring shaft moves at the same speed as the stirring, making it difficult to break up, thus reducing the stirring effect.

[0005] Therefore, there is an urgent need to develop a new, highly efficient gas-liquid mass transfer device. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by promoting thorough mixing of materials, increasing the gas-liquid mass transfer rate, reducing stirring power, and proposing a high-efficiency gas-liquid mass transfer device and its application.

[0007] To achieve the above objectives, the present invention provides a high-efficiency gas-liquid mass transfer device, the device comprising a vessel body, a stirrer, and a hollow baffle.

[0008] The stirrer is disposed inside the reactor vessel;

[0009] The hollow baffle is disposed inside the side wall of the vessel body, and the hollow baffle is provided with an air outlet.

[0010] The vessel body is provided with a liquid phase inlet, a liquid phase outlet, a gas phase inlet, and a gas phase outlet;

[0011] The liquid phase inlet is located at the top and / or side wall of the reactor body; the liquid phase outlet is located at the bottom of the reactor body.

[0012] The gas phase inlet is located on the top and / or side wall of the reactor body, and the gas phase inlet is connected to the hollow baffle through an inner tube;

[0013] The gas phase outlet is located at the top of the reactor body.

[0014] According to the present invention, preferably, the number of hollow baffles is multiple; more preferably, the number of hollow baffles is 2-6; and more preferably, the multiple hollow baffles are interconnected.

[0015] According to the present invention, preferably, the hollow baffle is provided with an air outlet on its end face and / or side face; the gas phase feed port is connected to the end face and / or side face of the hollow baffle through an inner tube.

[0016] According to the present invention, preferably, the hollow baffle is a convex hollow baffle, more preferably a hollow tube, and more preferably, the radial cross-section of the hollow tube is circular or elliptical;

[0017] In this invention, the hollow baffle is a convex hollow baffle. The term "convex" is known to those skilled in the art; it refers to a baffle whose surface curves outwards, and the open line segment connecting any two points on the baffle lies within it. Compared to common elongated baffles, convex hollow baffles are less prone to dead zones, thus reducing wall clogging.

[0018] According to the present invention, preferably, the hollow tube is a bottom-inwardly telescopic diameter type or a bottom-inwardly extending oblique opening type.

[0019] According to the present invention, preferably, the hollow baffle is further provided with a branch pipe on its side, the branch pipe facing the center of the vessel body and having an axial angle of not less than 30° with the hollow baffle; the end face and / or side face of the branch pipe are also provided with an air outlet.

[0020] According to one embodiment of the present invention, when the hollow baffle is provided with a branch pipe, the end face of the hollow baffle may not be provided with an air outlet.

[0021] According to the present invention, preferably, the diameter of the branch pipe is less than or equal to the diameter of the hollow baffle or the hydraulic diameter; the ratio of the length of the branch pipe to the inner diameter of the vessel body does not exceed 1:3.

[0022] According to the present invention, preferably, the air outlet of the branch pipe is a narrowed or oblique opening.

[0023] According to the present invention, preferably, the diameter of the reduced diameter opening of the branch pipe is 0.1-0.5 times the diameter of the branch pipe.

[0024] According to the present invention, preferably, the angle of the bevel of the branch pipe is 0°-60° with the axial direction of the branch pipe.

[0025] According to the present invention, preferably, the vent is a round hole, a square hole, a triangular hole, or an irregularly shaped hole.

[0026] According to the present invention, preferably, there are multiple air outlets.

[0027] According to the present invention, preferably, the diameter or hydraulic diameter of the air outlet is 0.5-25 mm.

[0028] According to one embodiment of the present invention, at least one air outlet is independently provided on the end face of the hollow baffle and the end face of the branch pipe; a plurality of air outlets are provided on the side surface of the hollow baffle in a direction at 30°-60° with the center line of the vessel body in the radial cross-sectional direction; a plurality of air outlets are uniformly provided on the side surface of the branch pipe in the circumferential direction.

[0029] According to the present invention, preferably, the stirrer includes a stirring shaft and a stirring paddle; the stirring shaft is located at the central axis of the vessel body, one end of the stirring shaft is connected to the top of the vessel body, and the other end is connected to the stirring paddle.

[0030] According to the present invention, preferably, the number of layers of the impeller blades is at least one; the impeller blades of the impeller are radial and / or axial flow type; and the ratio of the diameter of the impeller blades to the inner diameter of the vessel body is (1-4):(4-5).

[0031] According to the present invention, preferably, the radial flow type is a flat-bladed paddle and / or a turbine type;

[0032] According to the present invention, preferably, the axial flow type is a screw type and / or a propeller type.

[0033] The technical principle of this invention is as follows:

[0034] For gas-liquid mass transfer and reaction, theoretically, under the same mass transfer driving force, a larger gas-liquid interface results in a greater mass transfer flux and a better mass transfer effect. When the stirrer speed is constant, the liquid velocity at the gas outlet is also constant. With the gas and vessel pressure remaining constant, this invention sets multiple outlet holes of different sizes based on the gas flow rate, allowing the gas to be injected into the liquid at high speed, thereby changing the interface size and improving gas-liquid mass transfer. Smaller orifice diameters can generate smaller bubbles. Under stirring, these bubbles become even smaller. For a bubble cluster of the same volume, the smaller the individual bubbles, the greater the number of bubbles, and the larger the total surface area, thus increasing the gas-liquid mass transfer area.

[0035] For the coagulation process of polymer solutions such as adhesives, under certain temperature and pressure, the gas ejection velocity and the shear of stirring together determine the particle size of the adhesive particles. Under the condition that the gas and the pressure inside the vessel remain constant, at the same gas flow rate, setting multiple gas outlets of different sizes to eject the gas at high speed optimizes the particle size and improves the coagulation effect.

[0036] Another aspect of the present invention provides the application of the aforementioned high-efficiency gas-liquid mass transfer device in unsaturated polymer hydrogenation processes and polymer solution stripping processes.

[0037] According to the present invention, preferably, the unsaturated polymer hydrogenation process is at least one of SBS hydrogenation process, SIS hydrogenation process, NBR hydrogenation process and PS hydrogenation process.

[0038] According to the present invention, preferably, the stripping process of the polymer solution is a wet coagulation process, wherein the wet coagulation process is at least one of the following: stripping coagulation of styrene-butadiene rubber (SSBR, SBS), stripping coagulation of (low-type) cis-butadiene rubber, stripping coagulation of (halogenated) butyl rubber, and stripping coagulation of hydrogenated nitrile rubber.

[0039] The beneficial effects of the technical solution of the present invention are as follows:

[0040] 1) This invention uses hollow baffles in the form of internal tubes. While the hollow baffles act as stirrer baffles to promote material mixing, they can also send gas into the vessel without the need for additional internal tubes, simplifying the internal structure of the vessel and reducing wall blockage. Moreover, the hollow baffles are symmetrically arranged with reasonable openings, which plays a good role in gas distribution, expands the gas-liquid contact area, promotes the full diffusion of gas in the solution, effectively improves the gas-liquid mass transfer efficiency, and can reduce the power consumption of the stirring shaft under the same stirring effect, thus saving energy and reducing consumption.

[0041] 2) This invention has strong applicability and can be applied to most vapor-liquid mass transfer processes, such as hydrogenation processes of various unsaturated polymers in various polymer fields, as well as stripping processes of polymer solutions.

[0042] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0043] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0044] Figure 1 A schematic diagram of a high-efficiency gas-liquid mass transfer device provided in Embodiment 1 of the present invention is shown.

[0045] Figure 2 A schematic diagram of a high-efficiency gas-liquid mass transfer device provided in Embodiment 2 of the present invention is shown.

[0046] Figures 3(a)-(d) show schematic diagrams of four forms of hollow tubes for a high-efficiency gas-liquid mass transfer device provided by the present invention ((a) - straight tube type; (b) - bottom inner telescopic diameter type; (c) - straight tube and side branch tube type; (d) - bottom inner extension oblique opening type).

[0047] Figure 4 The diagram shows a top view of the internal hollow baffle with branch pipes of a high-efficiency gas-liquid mass transfer device provided by the present invention.

[0048] The annotations in the attached figures are explained as follows:

[0049] 1-Cessel body; 2-Top liquid inlet; 2.1-Lower liquid inlet on the side wall; 3-Gas outlet; 4-Gas inlet; 5-Middle liquid inlet on the side wall; 6-Liquid outlet; 7-Agitator; 8-Hollow baffle; 9-Inner tube; 10-Branch pipe. Detailed Implementation

[0050] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0051] Example 1

[0052] This embodiment provides a high-efficiency gas-liquid mass transfer device, such as... Figure 1As shown, the device includes a vessel body 1, a stirrer 7, and a hollow baffle 8;

[0053] The stirrer 7 is disposed inside the vessel body; the stirrer 7 includes a stirring shaft and a stirring paddle; the stirring shaft is located at the central axis of the vessel body 1, one end of the stirring shaft is connected to the top of the vessel body 1, and the other end is connected to the stirring paddle. The stirring paddle has four layers of blades, the top two layers are 45° inclined blades, and the bottom two layers are turbine blades, each layer includes four blades, the blade diameter is 900mm, and the width is 150mm; the stirring speed is 240rpm.

[0054] The high-efficiency gas-liquid mass transfer device of this embodiment is applied in the hydrogenation process of unsaturated polymers. The reactor body 1 is an SBS hydrogenation reactor with a diameter of DN2400 mm and a tangential length of 6000 mm.

[0055] The hollow baffles 8 are internally disposed on the side wall of the vessel body 1. There are four hollow baffles 8, each a hollow tube, as shown in Figure 3(c). The radial cross-section of the hollow tube is circular, with a straight tube length of 3500mm and a diameter of φ150mm. Three side branch tubes are arranged on the side of the hollow baffles 8 facing the axial direction. The branch tubes extend for 450mm and have a diameter of φ80mm, converging to φ15mm at a length of 400mm. Figure 4 As shown; a circular hole is provided on the bottom end face of the hollow baffle; the branch pipe has two rows of five circular holes evenly spaced at a 40° angle, and the diameter of the circular holes is φ8mm.

[0056] The vessel body 1 is provided with a liquid phase inlet, a liquid phase outlet 6, a gas phase inlet 4, and a gas phase outlet 3;

[0057] The liquid phase inlet includes a liquid phase inlet 2 located at the top of the vessel body and a liquid phase inlet 5 located in the middle of the side wall; the liquid phase outlet 6 is located at the lower part of the vessel body 1.

[0058] There are four gas phase feed ports 4, which are located on the top of the reactor body 1, and the gas phase feed ports 4 are connected to the hollow baffle 8 through the inner tube 9.

[0059] The gas phase outlet 3 is located at the top of the vessel body 1.

[0060] In this embodiment, intermittent hydrogenation is performed as follows:

[0061] A 10wt% SBS adhesive solution at 90℃ is introduced into reactor 1 through the top liquid phase inlet 2, reaching a liquid level of 60%. The catalyst and initiator are introduced into reactor 1 through the liquid phase inlet 5 in the middle of the side wall. After stirring is started, hydrogen gas is introduced into reactor 1 through the gas phase inlet 4, then through the inner tube 9 to the hollow baffle 8, reaching the bottom of reactor 1. Reactor 1 is maintained at 90℃ and 0.5MPa for approximately 1-4 hours for the hydrogenation reaction. After the hydrogenation reaction is complete, reactor 1 is depressurized, and the hydrogenation tail gas is discharged from the top gas phase outlet 3, while the product adhesive solution is discharged from the liquid phase outlet 6 and sent downstream for further processing.

[0062] The product obtained by the apparatus in this embodiment has a qualified degree of hydrogenation, and the amount of adhesive residue on the reactor body is reduced.

[0063] Example 2

[0064] This embodiment provides a high-efficiency gas-liquid mass transfer device, such as... Figure 2 As shown, the device includes a vessel body 1, a stirrer 7, and a hollow baffle 8;

[0065] The stirrer 7 is disposed inside the vessel body 1; the stirrer 7 includes a stirring shaft and a stirring paddle; the stirring shaft is located at the central axis of the vessel body 1, one end of the stirring shaft is connected to the top of the vessel body 1, and the other end is connected to the stirring paddle. The stirring paddle has four layers of blades, the top three layers are 45° inclined blades, and the bottom layer is a turbine blade, each layer includes four blades, the blade diameter is 750mm, and the width is 100mm; the stirring speed of the stirrer 7 is 180rpm.

[0066] The high-efficiency gas-liquid mass transfer device in this embodiment is applied in the rubber coagulation process. The vessel body 1 is the first vessel of the stripping coagulation vessel for styrene-butadiene rubber solution. The diameter of the vessel body 1 is DN2100 mm and the tangential length is 5000 mm.

[0067] The vessel body 1 is provided with a liquid phase inlet, a liquid phase outlet 6, a gas phase inlet 4, and a gas phase outlet 3;

[0068] The liquid phase feed inlet includes a liquid phase feed inlet 5 located in the middle of the side wall of the reactor body and a liquid phase feed inlet 2.1 located at the lower part of the side wall; the liquid phase discharge outlet 6 is located at the lower part of the reactor body 1;

[0069] There are two gas phase inlets 4, which are located on the side wall of the reactor body, and the gas phase inlets 4 are connected to two symmetrically arranged hollow baffles through an inner tube 9.

[0070] The gas phase outlet 3 is located at the top of the vessel body 1.

[0071] The hollow baffle 8 is disposed inside the side wall of the vessel body 1. There are 4 hollow baffles 8. The hollow baffle 8 is a hollow tube with a circular radial cross section. The hollow tube connected to the gas phase inlet 4 adopts the structure shown in Figure 3(b). The straight tube is 2200mm long, has a diameter of φ100mm, and extends 350mm from the end. It narrows to φ50mm at 300mm.

[0072] This embodiment uses a traditional three-reactor condensation process, with the following operating conditions for the first reactor:

[0073] Styrene-butadiene rubber solution, with a concentration of 20% wt (solvent is hexane, temperature is 60℃), enters the reactor body 1 through the liquid phase inlet 2.1 at the lower part of the side wall, with a flow rate of 10 t / h;

[0074] Circulating hot water (temperature 65℃, containing 15kg / h of dispersant) enters the vessel 1 through the liquid phase feed port 5 in the middle of the side wall at a flow rate of 35t / h (containing 0.04% dispersant);

[0075] Low-pressure steam at 0.5 MPaG and 170℃ enters the reactor body 1 from the gas phase feed inlet 4 at a flow rate of 3 t / h;

[0076] The temperature of the vessel body 1 is 81℃ and the pressure is 0.03MPaG.

[0077] The particle size of the gel-water obtained by the apparatus in this embodiment is 2-5mm. After post-treatment, the VOC content is within acceptable limits, and the amount of gel adhering to the reactor body is reduced.

[0078] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A high-efficiency gas-liquid mass transfer device, characterized in that, The device includes a vessel body, a stirrer, and a hollow baffle. The stirrer is disposed inside the reactor vessel; The hollow baffle is disposed inside the side wall of the vessel body, and the hollow baffle is provided with an air outlet. The vessel body is provided with a liquid phase inlet, a liquid phase outlet, a gas phase inlet, and a gas phase outlet; The liquid phase inlet is located at the top and / or side wall of the reactor body; the liquid phase outlet is located at the bottom of the reactor body. The gas phase inlet is located on the top and / or side wall of the reactor body, and the gas phase inlet is connected to the hollow baffle through an inner tube; The gas phase outlet is located at the top of the reactor body.

2. The high-efficiency gas-liquid mass transfer device according to claim 1, wherein, The number of hollow baffles is multiple; Preferably, the number of hollow baffles is 2-6; Preferably, the multiple hollow baffles are interconnected.

3. The high-efficiency gas-liquid mass transfer device according to claim 1, wherein, The hollow baffle is provided with an air outlet on its end face and / or side face; the gas phase feed port is connected to the end face and / or side face of the hollow baffle through an inner tube. The hollow baffle is a convex hollow baffle, preferably a hollow tube, and more preferably, the radial cross-section of the hollow tube is circular or elliptical. More preferably, the hollow tube is a bottom-inwardly telescopic type or a bottom-inwardly extending oblique type.

4. The high-efficiency gas-liquid mass transfer device according to claim 1, wherein, The hollow baffle is also provided with a branch pipe on its side, the branch pipe facing the center of the vessel body and having an axial angle of not less than 30° with the hollow baffle; the end face and / or side face of the branch pipe are also provided with air outlets.

5. The high-efficiency gas-liquid mass transfer device according to claim 4, wherein, The diameter of the branch pipe is less than or equal to the diameter of the hollow baffle or the hydraulic diameter; the ratio of the length of the branch pipe to the inner diameter of the vessel body does not exceed 1:3; The air outlet of the branch pipe is a reduced diameter opening or an oblique opening; Preferably, the diameter of the reduced-diameter opening of the branch pipe is 0.1-0.5 times the diameter of the branch pipe; Preferably, the angle of the bevel of the branch pipe is 0°-60° with the axial direction of the branch pipe.

6. The high-efficiency gas-liquid mass transfer device according to claim 1 or 4, wherein, The air outlet can be a round hole, a square hole, a triangular hole, or an irregularly shaped hole; The air outlet is multiple; The diameter or hydraulic diameter of the air outlet is 0.5-25 mm.

7. The high-efficiency gas-liquid mass transfer device according to claim 1, wherein, The stirrer includes a stirring shaft and a stirring paddle; the stirring shaft is located at the central axis of the vessel body, one end of the stirring shaft is connected to the top of the vessel body, and the other end is connected to the stirring paddle.

8. The high-efficiency gas-liquid mass transfer device according to claim 7, wherein, The impeller blades have at least one layer; the impeller blades are radial and / or axial flow type; the ratio of the diameter of the impeller blades to the inner diameter of the vessel body is (1-4):(4-5). Preferably, the radial flow type is a flat-bladed paddle and / or a turbine type; Preferably, the axial flow type is a screw type and / or a propeller type.

9. The application of the high-efficiency gas-liquid mass transfer device according to any one of claims 1-8 in the hydrogenation process of unsaturated polymers and the stripping process of polymer solutions.

10. The application according to claim 9, wherein, The unsaturated polymer hydrogenation process is at least one of SBS hydrogenation process, SIS hydrogenation process, NBR hydrogenation process and PS hydrogenation process; The stripping process of the polymer solution is a wet coagulation process, which is at least one of the following: stripping coagulation of styrene-butadiene rubber, stripping coagulation of cis-butadiene rubber, stripping coagulation of butyl rubber, and stripping coagulation of hydrogenated nitrile butadiene rubber.

Images