Dissolving machine for dissolving cellulose in NMMO (N-methylmorpholine-N-oxide) solution

Abstract

The utility model relates to a dissolving machine for dissolving cellulose in an NMMO solution, which comprises a dissolving tank, a stirrer and a cover part, the dissolving tank is provided with an inner cavity, a feeding and sampling port and a vacuum connector, the feeding and sampling port and the vacuum connector are respectively communicated with the inner cavity, and the cover part is hermetically connected to the feeding and sampling port; the stirrer comprises a motor, a stirring shaft, a first paddle and a second paddle, the first paddle and the second paddle are arranged in the inner cavity, one end of the stirring shaft is in transmission connection with the motor, and the other end extends into the inner cavity; the first paddle is connected to the stirring shaft, a knife edge is arranged on one side of the first paddle, and the first paddle is used for scraping up slurry porridge; the second paddle comprises a stirring rod and a cutting part, the stirring rod is connected to the stirring shaft, a film forming gap is formed between the stirring rod and the bottom of the inner cavity, and the cutting part is arranged on the stirring rod and used for cutting slurry porridge or a film; the experimental conclusion obtained by the dissolving machine can better guide mass production, and the required dissolving time is generally only 10-30 minutes, so that the experimental efficiency can be effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of evaporation and dissolution equipment, and particularly relates to a dissolver for dissolving cellulose in an NMMO solution. Background Art

[0002] Lyocell fiber (referred to as Lyocell) is a regenerated cellulose fiber obtained by physical dissolution and regeneration from wood pulp (such as cotton pulp, bamboo pulp, etc.). Different from other regenerated cellulose fibers, the solvent for producing Lyocell fiber is an environmentally friendly solvent (i.e., NMMO solution), and the used solvent can be recycled. Moreover, Lyocell fiber has excellent performance characteristics such as non-toxicity, breathability, moisture absorption, skin-friendliness, and high strength, and can be widely used in the textile and clothing industries and other industrial fields.

[0003] In the actual production process of Lyocell fiber, it is usually necessary to send the pulp porridge into a thin-film evaporator to complete the dissolution process. The pulp porridge is a mixture composed of fibers and an NMMO solution. The thin-film evaporator is essentially a highly efficient evaporation and concentration device, and its working principle is that the material flows in a film shape along the heating tank wall, so as to achieve high-efficiency heat transfer and rapid evaporation of water; in the production process of Lyocell fiber, the pulp porridge is repeatedly scraped into a thin film from top to bottom along the wall of the thin-film evaporator from the inlet. Under vacuum conditions, the water in the pulp porridge quickly evaporates, the concentration of NMMO increases, and the fiber dissolves into a gel. The thin-film evaporator is the core equipment in the production process of Lyocell fiber.

[0004] In the prior art, the thin-film evaporator applied to the actual production process of Lyocell fiber is a medium- to large-sized device. It is very difficult for the inner diameter of the thin-film evaporator to be less than 800 mm, the height is greater than 6000 mm, and the amount of fiber dissolved at one time is usually not less than 100 kg. It is not suitable for use in R & D laboratories and testing laboratories when conducting fiber dissolution experiments because the amount of fiber required for fiber dissolution experiments in R & D laboratories and inspection and testing laboratories usually does not exceed 500 g. In fact, currently, a rotary evaporator is usually used to conduct experiments on dissolving fibers in NMMO solution in the laboratory. The rotary evaporator can make the medium (pulp porridge) tumble as the container rotates under the conditions of vacuum pumping and heating. However, the medium tumbles in a whole mass, and the water on its surface can evaporate due to vacuum pumping. As the concentration of NMMO water on the surface increases due to evaporation, the fiber dissolves into a gel, and the water inside is not easily evaporated due to the sealing of the surface colloid. Therefore, when using a rotary evaporator to conduct experiments on dissolving fibers in NMMO solution, the fiber dissolution time is very long, generally exceeding 120 minutes, while in the production of Lyocell fiber, the fiber usually dissolves into a gel in only 10 - 30 minutes. Therefore, when using a rotary evaporator to conduct experiments on dissolving fibers in NMMO, on the one hand, the required time is long, resulting in very low experimental efficiency. On the other hand, due to the large difference in the working principles between the rotary evaporator and the thin-film evaporator, the experimental conclusions obtained using the rotary evaporator have no guiding significance for large-scale production, which urgently needs to be solved. Summary of the Invention

[0005] In the first aspect, the present utility model aims to solve the above technical problems by providing a dissolver, which not only has basically the same working principle as the thin-film evaporator and basically the same dissolution time, so that the experimental conclusions obtained using this dissolver can better guide large-scale production, but also usually only takes 10 - 30 minutes for dissolution, which can effectively improve the experimental efficiency. The main idea is as follows:

[0006] A dissolving machine for dissolving cellulose in NMMO solution, comprising a dissolving tank, an agitator and a cover component, wherein the dissolving tank is constructed with an inner cavity, a feeding sampling port and a vacuum connector, the feeding sampling port and the vacuum connector are respectively connected to the inner cavity, the inner cavity is used to provide a reaction place, the vacuum connector is used to connect a vacuum tube, and the cover component is sealed and connected to the feeding sampling port; the agitator comprises a motor, a stirring shaft, a first blade and a second blade arranged in the inner cavity, one end of the stirring shaft is connected to the motor transmission, and the other end extends into the inner cavity, the motor is used to drive the stirring shaft to rotate, the first blade is connected to the stirring shaft, one side of the first blade is provided with a knife edge, the first blade is used to scrape up the porridge at the bottom of the inner cavity, the second blade comprises a stirring rod and a cutting component, the stirring rod is connected to the stirring shaft, a film-forming gap is formed between the stirring rod and the bottom of the inner cavity, and the cutting component is arranged on the stirring rod for cutting the porridge or film. In the present scheme, a first paddle is configured and a blade is configured on one side of the first paddle so that the porridge at the bottom of the inner cavity can be scraped by the first paddle and the porridge can be rolled as the stirring shaft rotates to achieve uniform heating of the porridge; at the same time, a second paddle is configured and the second paddle is configured to include a stirring rod and a cutting component for cutting the porridge or film so that the second paddle can be used to continuously cut and separate the porridge or film turned up by the first paddle, so that the first paddle and the second paddle are used in coordination with each other, and the porridge is repeatedly film-formed, the film is broken, and the porridge (or glue) is rolled through the coordination of the two, so that the surface area of ​​the porridge (or glue) is maximized and heated evenly, the water therein evaporates rapidly under vacuum conditions, the NMMO concentration rapidly increases to more than 87%, and the cellulose is dissolved in the NMMO solution to form a gel; by reserving a film-forming gap between the stirring rod and the bottom of the inner cavity, the size of the film-forming gap can be used to effectively control the film thickness. With such a design, on the one hand, when the dissolving machine is used to conduct experiments on the dissolution of cellulose in NMMO solution, the dissolution process is consistent with the working principle of the thin-film evaporator commonly used in large-scale production, and the slurry is repeatedly film-formed to evaporate water under vacuum heating conditions; at the same time, the time required for the dissolution process is basically consistent with the time used by the thin-film evaporator commonly used in large-scale production, so that the experimental conclusions obtained by using the dissolving machine can better guide large-scale production; on the other hand, when the dissolving machine is used to conduct experiments on the dissolution of cellulose in NMMO solution, the dissolution time is usually only 10 to 30 minutes, which can effectively improve the experimental efficiency; in addition, the size of the dissolving machine can be made very small, and the amount of dissolved fiber can also be lower, which can meet the experimental detection needs of different fiber amounts and is more conducive to application in research and development laboratories, inspection and testing laboratories and other occasions.

[0007] In order to better guide mass production, preferably, the height of the film-forming gap is 5 to 7 mm. Thus, the film thickness of the dissolving machine can be controlled to be 5 to 7 mm, which is consistent with the film thickness of the thin film evaporator, so that the experimental conclusions obtained by using the dissolving machine can better guide mass production.

[0008] In the second aspect of the present utility model, it is necessary to solve the problem of cooperating with the first blade and efficiently cutting and separating the pulp porridge and the film. Preferably, the second blade is provided with at least two cutting components, and each cutting component is respectively arranged on the stirring rod and evenly arranged along the radial direction of the stirring shaft. By arranging at least two cutting components and making each cutting component evenly arranged along the radial direction of the stirring shaft, the cutting effect and cutting efficiency can be further improved, thereby being more conducive to shortening the dissolution time.

[0009] Preferably, one side of the cutting component is constructed as a pointed structure; and / or, the lower end of the cutting component extends into the film-forming gap. So as to better cut and separate the formed film.

[0010] To solve the problem of more thoroughly scraping up the pulp porridge or film at the bottom of the inner cavity, further, the lower end of the first blade maintains an interval of 0.5 - 1 mm from the bottom of the inner cavity, and the first blade rotates relative to the bottom of the inner cavity driven by the motor. So as to perform a scraping action along the bottom of the inner cavity, thereby being able to more thoroughly scrape up the pulp porridge or film at the bottom of the inner cavity.

[0011] To solve the problem of reducing the load of the motor, further, the first blade is arranged obliquely in the vertical direction. So that the cutting edge on one side of the first blade can more labor-savingly scrape up the pulp porridge at the bottom of the inner cavity, which can not only guide the scraped pulp porridge to turn up upwards so that the scraped pulp porridge can be better cut by the second blade, but also effectively reduce the resistance of the first blade, which can not only prevent the situation of jamming, but also greatly reduce the load of the motor.

[0012] Preferably, the lower surface of the first blade forms an angle of 10° - 20° with the bottom of the inner cavity. Thus, it is more conducive to scraping up the pulp porridge or film at the bottom.

[0013] Preferably, along the radial direction of the stirring shaft, the cross-sectional shape of the first blade remains unchanged. It is both conducive to scraping the film and conducive to more uniform film formation.

[0014] To solve the problem of facilitating installation and disassembly, further, the stirrer further includes a bushing. The first blade and the second blade are respectively connected to the bushing. The bushing is constructed with a central hole adapted to the stirring shaft. The bushing is sleeved on the stirring shaft through the central hole and is detachably installed on the stirring shaft through a fastener. So as to install, disassemble and replace the whole stirrer.

[0015] Preferably, the first blade and the second blade are respectively welded to the bushing.

[0016] Preferably, the side surface of the bushing is constructed with an assembly hole, and the assembly hole is communicated with the central hole. The bushing is connected to the stirring shaft through a fastener adapted to the assembly hole. So as to realize the detachable connection between the bushing and the stirring shaft.

[0017]

[0017] To achieve better film forming effect and efficiency, further, it includes at least two first blades and at least two second blades. The first blades and the second blades are respectively arranged uniformly along the circumferential direction of the stirring shaft, and the first blades and the second blades are arranged alternately. It can effectively ensure the film forming quality and is conducive to achieving better film forming effect and efficiency.

[0018] Further, the dissolving tank includes a tank body and a tank cover. An opening is formed at the top of the tank body, and a first flange is formed along the circumferential direction of the opening. The tank cover is provided with a second flange adapted to the first flange, and the tank cover is hermetically connected to the tank body through the cooperation of the second flange and the first flange; a through hole for passing through the stirring shaft is formed at the central position of the tank cover, and a mechanical seal is arranged between the stirring shaft and the tank cover; the feeding and sampling port and the vacuum connector are respectively arranged on the tank cover.

[0019]

[0018] The third aspect of the present utility model aims to solve the problem of precisely controlling the temperature inside the tank. Further, the outside of the tank body is also coated with a jacket. The jacket includes a heating chamber for heating the tank body. Heat transfer oil is filled in the heating chamber, and an electric heating component is also arranged in the heating chamber;

[0020] It also includes a control module and a temperature sensor. The electric heating component, the temperature sensor, and the motor are respectively connected to the control module. The temperature sensor is used to detect the temperature of the heat transfer oil, and the control module is used to control the temperature of the heat transfer oil within the set threshold range. In this solution, by configuring the jacket and arranging the electric heating component and the heat transfer oil in the jacket, the electric heating component generates heat when powered on to heat the heat transfer oil in the jacket. After the temperature of the heat transfer oil rises, it can heat the tank body, so as to achieve the purpose of uniformly heating the medium in the tank. By configuring the control module and the temperature sensor and connecting the electric heating component and the temperature sensor to the control module respectively, the temperature sensor can detect the real-time temperature of the heat transfer oil, and the control module can control the electric heating component according to the temperature feedback by the temperature sensor, so as to precisely control the temperature of the heat transfer oil, make the temperature of the heat transfer oil always within the set threshold range, and thus achieve the purpose of precisely controlling the temperature inside the tank, which is conducive to achieving a better and more uniform heating effect.

[0021]

[0019] Further, the electric heating component is an electric heating tube, and the electric heating tube is arranged in a spiral shape. The spiral electric heating tube can not only effectively increase the contact area with the heat transfer oil and improve the heating efficiency, but also cover a larger area, which is conducive to more uniform heating of the heat transfer oil.

[0022] Further, the inner diameter of the inner cavity is 120 mm to 300 mm; the height of the inner cavity is 120 mm to 240 mm.

[0023] Preferably, the inner diameter of the inner cavity is 240 mm; the height of the inner cavity is 180 mm.

[0024] Compared with the prior art, a dissolver for dissolving cellulose in an NMMO solution provided by the present utility model has the following beneficial effects:

[0025] First, the volume of this dissolver can be made small, and the amount of dissolved fiber can also be low, which can meet the fiber amount required for fiber dissolution experiments in R & D laboratories and inspection and testing laboratories, such as 50 - 240 grams per time.

[0026] Second, when using this dissolver to conduct an experiment on dissolving cellulose in an NMMO solution, the working principle of the dissolution process is the same as that of the thin - film evaporator commonly used in large - scale production. Under vacuum heating conditions, the pulp porridge is repeatedly formed into a film to evaporate water; at the same time, the time required for the dissolution process is basically the same as that of the thin - film evaporator commonly used in large - scale production, so that the experimental conclusions obtained using this dissolver can better guide large - scale production.

[0027] Third, when using this dissolver to conduct an experiment on dissolving cellulose in an NMMO solution, usually only 10 - 30 minutes of dissolution time is required, which can effectively improve the experimental efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present utility model, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0029] Figure 1 It is the front view of a dissolver provided by an embodiment of the present utility model.

[0030] Figure 2 It is a partial cross - sectional view of the bottom of the dissolution tank in a dissolver provided by an embodiment of the present utility model.

[0031] Figure 3 It is Figure 1 The cross - sectional view at A - A in

[0032] Figure 4 It is Figure 1 The cross - sectional view at B - B in

[0033] Description of the reference numerals in the figure: dissolution tank 1, tank body 11, inner cavity 12, first flange 13, tank cover 14, second flange 15, cover component 16, support 161, feeding and sampling port 17, vacuum connector 18; agitator 2, motor 21, reducer 22, coupling 23, stirring shaft 24, shaft sleeve 25, mechanical seal 26; first paddle 3, blade edge 31; second paddle 4, stirring rod 41, film forming gap 42, cutting component 43, pointed structure 44; jacket 5, heating cavity 51, electric heating component 52; frame 6; sealing ring 7; fastener 8. Detailed implementation manners

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but only represents the selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] Embodiment 1

[0036] Please refer to Figure 1 , in this embodiment, a dissolver for dissolving cellulose in an NMMO solution is provided, including a dissolution tank 1, an agitator 2 and a cover component 16. Among them,

[0037] As Figure 1 and Figure 4 shown, the dissolution tank 1 is configured with an inner cavity 12, a feeding and sampling port 17 and a vacuum connector 18. The feeding and sampling port 17 and the vacuum connector 18 are respectively communicated with the inner cavity 12. The inner cavity 12 is mainly used to provide a reaction site for evaporation and dissolution. The shape of the inner cavity 12 can be determined according to actual needs. To better adapt to the agitator 2, in this embodiment, at least the lower end of the inner cavity 12 is configured as a cylindrical structure. As Figure 1As shown, for example, during implementation, the entire inner cavity 12 can be configured as a cylindrical structure. During implementation, the size of the inner cavity 12 can be determined according to actual requirements. However, for the miniaturization of the device, in a preferred implementation, the inner diameter of the inner cavity 12 can preferably be designed to be 120 mm to 300 mm; and the height of the inner cavity 12 can also preferably be designed to be 120 mm to 240 mm. With such a size of the inner cavity 12, it can fully meet the various fiber amounts required for fibrinolytic experiments in research and development laboratories and inspection and testing laboratories. As an example, in this embodiment, the inner diameter of the inner cavity 12 is 240 mm, and the height of the inner cavity 12 is 180 mm. A dissolver with such dimensions can dissolve 50 to 100 grams of fibers at one time, and is suitable for laboratory research and the detection of the dissolution performance of fiber raw materials in factories.

[0038] In this embodiment, as Figure 4 shown, the vacuum connector 18 is mainly used to connect a vacuum tube, so as to connect a negative pressure device such as a vacuum pump using the vacuum tube. During implementation, the vacuum connector 18 can adopt existing vacuum pipeline connectors, and no further examples will be given here.

[0039] In this embodiment, as Figure 1 and Figure 4 shown, the configuration of the feeding and sampling port 17 mainly facilitates the user to add media (or gruel or materials) into the dissolving tank 1, and also facilitates the user to take samples from the dissolving tank 1 after the experiment. Since the inner cavity 12 is in a vacuum state during actual use, in this dissolver, the cover member 16 is sealingly connected to the feeding and sampling port 17, as Figure 1 and Figure 4 shown, it can not only use the cover member 16 to close the feeding and sampling port 17 to prevent air leakage from the feeding and sampling port 17, but also use the cover member 16 to open the feeding and sampling port 17. During implementation, the cover member 16 is detachably connected to the dissolving tank 1. For example, the cover member 16 is configured with an internal thread, and correspondingly, the feeding and sampling port 17 is configured with an external thread adapted to the internal thread, so that the cover member 16 can be threadedly connected to the feeding and sampling port 17 of the dissolving tank 1 and close the feeding and sampling port 17. In addition, a sealing ring 7 can be provided between the cover member 16 and the dissolving tank 1 to improve the sealing performance at the feeding and sampling port 17. For example, an O-ring 7 can be provided inside the cover member 16. When the cover member 16 is threadedly connected to the feeding and sampling port 17, the O-ring 7 is just pressed between the cover member 16 and the feeding and sampling port 17, thereby improving the sealing performance and ensuring no air leakage under the required vacuum environment (such as -1 MPa); by setting the O-ring 7 at the end of the feeding and sampling port 17, the same effect can also be achieved, which will not be elaborated here. During use, when the medium film stirring experiment in the dissolving tank 1 reaches the set time, stop stirring rotation and vacuum pumping, and open the cover member 16 to take samples from the feeding and sampling port 17 to detect various indicators.

[0040] As Figures 1-3 shown, in this embodiment, the stirrer 2 includes a motor 21, a stirring shaft 24, a first paddle 3 and a second paddle 4 disposed in the inner cavity 12. One end of the stirring shaft 24 is drivingly connected to the motor 21, and the other end extends into the inner cavity 12 to drive the stirring shaft 24 to rotate by means of the motor 21. As Figure 3 shown, one ends of the first paddle 3 and the second paddle 4 are respectively connected to the stirring shaft 24 to drive the first paddle 3 and the second paddle 4 to rotate synchronously by means of the stirring shaft 24, so as to effectively stir the gruel in the inner cavity 12. As Figures 1-3 shown, in this embodiment, a cutting edge 31 is disposed on one side of the first paddle 3, the lower end of the first paddle 3 fits the bottom of the inner cavity 12, and the first paddle 3 rotates relative to the bottom of the inner cavity 12 under the drive of the motor 21 to perform a scraping action along the bottom of the inner cavity 12, so as to more thoroughly scrape the gruel or film at the bottom of the inner cavity 12. During implementation, the distance between the lower end of the first paddle 3 and the bottom of the inner cavity 12 can be determined according to actual needs. Preferably, a gap of 0.5-1 mm can be maintained between the lower end of the first paddle 3 and the bottom of the inner cavity 12, as Figure 2 shown.

[0041] During implementation, along the radial direction of the stirring shaft 24, the cross-sectional shape of the first paddle 3 remains unchanged, as Figure 1 and Figure 2 shown, which is beneficial to scraping the film at the bottom and also beneficial to forming a more uniform film. By way of example, as Figure 2 shown, the cross-sectional shape of the first paddle 3 is a right trapezoid.

[0042] During implementation, the first paddle 3 can be horizontally arranged or inclinedly arranged along the vertical direction. For example, in this embodiment, the first paddle 3 is inclinedly arranged along the vertical direction, as Figure 2 shown, which not only enables the cutting edge 31 on one side of the first paddle 3 to better fit the bottom of the inner cavity 12, thus facilitating more labor-saving scraping of the gruel at the bottom, but also can guide the scraped gruel to turn up, so that the scraped gruel can be better cut by the second paddle, and is more conducive to evaporating the water in the gruel; moreover, it can improve the force on the first paddle 3, reduce the resistance of the first paddle 3, prevent jamming, greatly reduce the load on the motor 21, and is beneficial to improving the service life and reliability of the first paddle 3. During implementation, the inclination angle of the first paddle 3 can be determined according to actual needs. Preferably, an angle of 10°-20° can be maintained between the lower surface of the first paddle 3 and the bottom of the inner cavity 12, as Figure 2 shown, which is more conducive to scraping the gruel or film at the bottom.

[0043] In this embodiment, the second blade 4 is mainly used for slicing the film and forming the film. In this embodiment, the second blade 4 includes a stirring rod 41 and a cutting member 43. One end of the stirring rod 41 is connected to the stirring shaft 24, so that the stirring shaft 24 can rotate synchronously with the stirring rod 41. During assembly, a film-forming gap 42 is reserved between the stirring rod 41 and the bottom of the inner cavity 12. As Figure 2 shown, the height of the film-forming gap 42 is the thickness of the formed film. During implementation, the height of the film-forming gap 42 can be determined according to actual requirements. Preferably, in this embodiment, the height of the film-forming gap 42 can be preferentially controlled to be 5-7 mm, so that the film-forming thickness of this dissolver can be 5-7 mm. Of course, it can be understood that in other embodiments, the height of the film-forming gap 42 can also be less than 5 mm or greater than 7 mm, and no further examples will be given here.

[0044] In this embodiment, the cutting member 43 is arranged on the stirring rod 41, as Figure 2 and Figure 3 shown, so as to use the cutting member 43 to slice the pulp porridge and the film, especially to slice the pulp porridge or film scraped up by the first blade 3. During implementation, the number of the cutting members 43 can be determined according to actual requirements. The number of the cutting members 43 can be one, two or more. To improve the slicing effect and efficiency, during implementation, at least two cutting members 43 can be configured, and each cutting member 43 can be evenly arranged along the radial direction of the stirring shaft 24. As an example, as Figure 2 and Figure 3 shown, the second blade 4 in this dissolver is configured with four cutting members 43, and each cutting member 43 is evenly arranged along the radial direction of the stirring shaft 24, which can significantly improve the slicing efficiency and is beneficial to further reducing the time required for dissolution.

[0045] During implementation, the shape of the cutting member 43 can be determined according to actual requirements. As an example, in this embodiment, one side of the cutting member 43 is configured as a pointed structure 44 to form a cutting edge convenient for slicing, as Figure 2 and Figure 3 shown, so as to better cut and separate the pulp porridge or the formed film. The lower end of the cutting member 43 can extend into the film-forming gap 42, as Figure 2 shown, so as to effectively slice the film formed in the film-forming gap 42.

[0046] In this embodiment, the first blade 3 and the second blade 4 are used in cooperation. Through their cooperation, the pulp porridge is repeatedly formed into a film, the film is broken, and the pulp porridge (or glue) is tumbled, so that the surface area of the pulp porridge (or glue) is maximized and the heating is uniform. Under vacuum conditions, the water therein evaporates rapidly, the NMMO concentration rapidly rises to exceed 87%, and the cellulose dissolves in the NMMO solution to form a gel. During implementation, the number of the first blades 3 and the second blades 4 can be determined according to actual needs. For example, the number of the first blades 3 can be one, two, three, etc. Similarly, the number of the second blades 4 can be one, two, three, etc. As an example, the stirrer 2 is configured with one first blade 3 and one second blade 4, and the first blade 3 and the second blade 4 are symmetrically connected to the stirring shaft 24 respectively. For another example, the stirrer 2 can include at least two first blades 3 and at least two second blades 4. The first blades 3 and the second blades 4 are respectively arranged uniformly along the circumferential direction of the stirring shaft 24, and the first blades 3 and the second blades 4 are arranged alternately, which can effectively ensure the film-forming quality and is conducive to achieving a better film-forming effect. As an example, as Figures 1-3 shown, the stirrer 2 is configured with two first blades 3 and two second blades 4. The first blades 3 and the second blades 4 are respectively arranged uniformly along the circumferential direction of the stirring shaft 24, and the first blades 3 and the second blades 4 are arranged alternately, so that the included angle between two adjacent first blades 3 and second blades 4 is 90 degrees.

[0047] During implementation, the first blade 3 and the second blade 4 can be respectively welded to the stirring shaft 24, or can be connected to the stirring shaft 24 through the fastener 8. In the preferred implementation manner provided in this embodiment, the stirrer 2 further includes a bushing 25. As Figures 1-3 shown, the first blade 3 and the second blade 4 are respectively connected to the bushing 25. For example, the first blade 3 and the second blade 4 can be respectively welded to the bushing 25. The bushing 25 is configured with a central hole adapted to the stirring shaft 24, so that the bushing 25 can be sleeved on the stirring shaft 24 through the central hole and can be detachably installed on the stirring shaft 24 through the fastener 8 for assembly, disassembly, maintenance, etc. For example, the side surface of the bushing 25 is configured with an assembly hole, and the assembly hole is communicated with the central hole, so that the bushing 25 can be fixed to the stirring shaft 24 through a fastener 8 such as a bolt or a screw adapted to the assembly hole. As Figures 1-3 shown.

[0048] During implementation, the dissolving tank 1 can be an integrally formed member. However, for the convenience of processing and manufacturing and for the convenience of assembling the stirrer 2, during implementation, the dissolving tank 1 can include a tank body 11 and a tank cover 14. As Figure 1As shown, the inner cavity 12 is formed in the tank body 11. An opening is formed at the top of the tank body 11, and the opening is communicated with the inner cavity 12. A first flange 13 is formed along the circumferential direction of the opening. Correspondingly, a second flange 15 adapted to the first flange 13 is formed on the tank cover 14, so that the tank cover 14 can be hermetically connected to the tank body 11 through the cooperation of the second flange 15 and the first flange 13. It can be understood that in order to improve the sealing performance, a sealing ring 7 can also be arranged between the first flange 13 and the second flange 15.

[0049] During implementation, as Figure 1 and Figure 4 shown, the feeding and sampling port 17 and the vacuum connector 18 can be respectively arranged on the tank cover 14. As shown in the figure, a through hole for passing through the stirring shaft 24 is formed at the central position of the tank cover 14, and a mechanical seal 26 is arranged between the stirring shaft 24 and the tank cover 14. The mechanical seal 26 can be realized by using the existing technology to ensure that air will not enter the dissolving tank 1 when the stirring shaft 24 rotates.

[0050] During actual use, the dissolving tank 1 can be directly placed on the installation foundation at the installation position. For example, in this embodiment, a rack 6 for bearing is further included. The dissolving tank 1 can be fixed to the rack 6, and the lower end of the dissolving tank 1 can be suspended, as Figure 1 shown, so as not to contact the ground. As an example, during implementation, the tank body 11 can be fixed to the rack 6 by means of welding or bolt connection, as Figure 1 shown. The motor 21 can also be fixed to the rack 6 and located above the dissolving tank 1. The output shaft of the motor 21 can be connected to the reducer 22 so as to use the reducer 22 to play a role in reducing speed and increasing torque. The output shaft of the reducer 22 can be connected to the coupling 23, and the connector is connected to the upper end of the stirring shaft 24, as Figure 1 shown, so that the motor 21 can drive the stirring shaft 24 to rotate. And for the convenience of installation and fixation of the motor 21 and the reducer 22, during implementation, as Figure 1 and Figure 4 shown, a bracket 161 is further included. The bracket 161 is connected to the tank cover 14, and the motor 21 and / or the reducer 22 can be installed on the bracket 161, so that the motor 21 is located above the stirring shaft 24.

[0051] Of course, in a more perfect solution, this dissolver further includes a control module, and the control module is connected to the motor 21 so as to use the control module to control the start-stop, rotation speed, etc. of the motor 21. During implementation, the control module can include existing control chips or control circuits, etc., which will not be exemplified one by one here.

[0052] Embodiment 2

[0053] To solve the problem of precisely controlling the temperature inside the tank body 11, the main difference between the second embodiment and the first embodiment described above is that for the dissolving machine provided in this embodiment, a jacket 5 is further covered outside the tank body 11. As Figures 1-3 shown, the jacket 5 includes a heating cavity 51 for heating the tank body 11. The heating cavity 51 is filled with heat-conducting oil. At the same time, an electric heating component 52 is also arranged in the heating cavity 51. The electric heating component 52 generates heat when powered on to heat the heat-conducting oil in the jacket 5. After the temperature of the heat-conducting oil rises, it can heat the tank body 11, so as to achieve the purpose of uniformly heating the medium in the tank.

[0054] In this embodiment, a temperature sensor is also configured. The electric heating component 52 and the temperature sensor are respectively connected to the control module. The temperature sensor can be arranged in the inner cavity 12 or at a position communicated with the inner cavity 12. The temperature sensor is mainly used to detect the temperature of the heat-conducting oil in the inner cavity 12 and feed it back to the control module. The control module can control the electric heating component 52 according to the temperature fed back by the temperature sensor, so as to precisely control the temperature of the heat-conducting oil, make the temperature of the heat-conducting oil always within the set threshold range, and thus achieve the purpose of precisely controlling the temperature inside the tank body 11, which is beneficial to achieving a better and more uniform heating effect.

[0055] During implementation, the electric heating component 52 can preferably adopt an existing electric heating tube, and the electric heating tube can be arranged in a spiral shape. As Figures 1-3 shown, the spirally arranged electric heating tube can not only effectively increase the contact area with the heat-conducting oil, improve the heating efficiency, but also cover a larger area, which is beneficial to more uniform heating of the heat-conducting oil.

[0056] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention.

Claims

1. A dissolver for dissolving cellulose in an NMMO solution, characterized in that, It includes a dissolution tank, a stirrer and a cover component. Among them, the dissolution tank is configured with an inner cavity, a feeding and sampling port and a vacuum connector. The feeding and sampling port and the vacuum connector are respectively communicated with the inner cavity. The inner cavity is used to provide a reaction site, and the vacuum connector is used to connect a vacuum tube. The cover component is hermetically connected to the feeding and sampling port; The stirrer includes a motor, a stirring shaft, a first paddle and a second paddle arranged in the inner cavity. One end of the stirring shaft is in transmission connection with the motor, and the other end extends into the inner cavity. The motor is used to drive the stirring shaft to rotate; the first paddle is connected to the stirring shaft, and a cutting edge is arranged on one side of the first paddle. The first paddle is used to scrape up the gruel at the bottom of the inner cavity; the second paddle includes a stirring rod and a cutting component. The stirring rod is connected to the stirring shaft, and a film-forming gap is formed between the stirring rod and the bottom of the inner cavity. The cutting component is arranged on the stirring rod and is used to cut the gruel or film.

2. The dissolver for dissolving cellulose in an NMMO solution according to claim 1, characterized in that, The second paddle is provided with at least two cutting components, and each cutting component is respectively arranged on the stirring rod and is evenly arranged along the radial direction of the stirring shaft.

3. The dissolver for dissolving cellulose in an NMMO solution according to claim 2, characterized in that, One side of the cutting component is configured as a pointed structure; And / or, the lower end of the cutting component extends into the film-forming gap.

4. The dissolver for dissolving cellulose in NMMO solution according to claim 1, characterized in that The lower end of the first paddle keeps an interval of 0.5-1 mm from the bottom of the inner cavity, and the first paddle rotates relative to the bottom of the inner cavity under the drive of the motor.

5. The dissolver for dissolving cellulose in NMMO solution according to claim 4, characterized in that, The first paddle is arranged obliquely in the vertical direction.

6. The dissolving machine for dissolving cellulose in an NMMO solution according to claim 1, wherein, It includes at least two first paddles and at least two second paddles. The first paddles and the second paddles are respectively evenly arranged along the circumferential direction of the stirring shaft, and the first paddles and the second paddles are arranged alternately; And / or, the stirrer further includes a bushing. The first paddle and the second paddle are respectively connected to the bushing. The bushing is configured with a central hole adapted to the stirring shaft. The bushing is sleeved on the stirring shaft through the central hole and is detachably installed on the stirring shaft through a fastener.

7. The dissolving machine for dissolving cellulose in NMMO solution according to claim 1, characterized in that, The dissolution tank includes a tank body and a tank cover. An opening is configured at the top of the tank body, and a first flange is configured along the circumferential direction of the opening. The tank cover is configured with a second flange adapted to the first flange, and the tank cover is hermetically connected to the tank body through the cooperation of the second flange and the first flange; A through hole for passing the stirring shaft is configured at the central position of the tank cover, and a mechanical seal is arranged between the stirring shaft and the tank cover; The feeding and sampling port and the vacuum connector are respectively arranged on the tank cover.

8. The dissolver for dissolving cellulose in NMMO solution according to claim 7, characterized in that, A jacket is further covered on the outer side of the tank body. The jacket includes a heating cavity for heating the tank body. Heat-conducting oil is filled in the heating cavity, and an electric heating component is further arranged in the heating cavity; It further includes a control module and a temperature sensor. The electric heating component, the temperature sensor and the motor are respectively connected to the control module. The temperature sensor is used to detect the temperature of the heat-conducting oil, and the control module is used to control the temperature of the heat-conducting oil within a set threshold range.

9. The dissolver for dissolving cellulose in an NMMO solution according to claim 8, characterized in that, The electric heating component uses an electric heating tube, and the electric heating tube is arranged in a spiral shape.

10. The dissolver for dissolving cellulose in NMMO solution according to any one of claims 1-7, characterized in that, The height of the film-forming gap is 5-7 mm; The inner diameter of the inner cavity is 120 mm-300 mm; The height of the inner cavity is 120 mm-240 mm.

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