Novel NMMO solvent evaporation concentrator

Abstract

The utility model relates to a novel NMMO solvent evaporation concentrator which comprises a concentration tank provided with a concentration cavity, a stirrer, a motor, a vertically arranged stirring shaft and blades arranged in the concentration cavity, the motor is in transmission connection with the stirring shaft, the lower end of the stirring shaft extends into the concentration cavity, the blades are connected to the stirring shaft, and a liquid distributor is arranged in the concentration cavity and used for distributing liquid to the stirring shaft. The liquid distributor is arranged in the concentration cavity and located above the blades, the liquid distributor comprises an outer cylinder matched with the concentration cavity and a grating structure arranged in the outer cylinder, an ascending channel is formed between the outer cylinder and the grating structure, and a guide part used for guiding liquid to deviate towards the center of the concentration cavity and fall back to the grating structure is constructed at the upper end of the outer cylinder; the concentration efficiency of the evaporation concentrator is higher than that of a rotary evaporator and is equivalent to that of a multi-effect evaporator, but the volume and the manufacturing cost of the evaporation concentrator are only 1 / 100 of those of the multi-effect evaporator, and liquid which can be concentrated by the evaporation concentrator each time is more than that of the rotary evaporator and can reach 10-50kg, so that the requirement of a Lyocell fiber pilot plant test is met very well.

Description

Technical Field

[0001] The utility model relates to the technical field of NMMO solution concentration equipment, and particularly relates to a novel NMMO solvent evaporation concentrator. Background Art

[0002] Lyocell fiber (abbreviation: Lyocell) is a regenerated cellulose fiber obtained by physical dissolution and regeneration using wood pulp (or cotton pulp, bamboo pulp, etc.) as raw materials. 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, air permeability, 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, NMMO solution (or bath solution) is an important solvent, and there is a link of evaporating and concentrating the NMMO solution (or bath solution) in the process. In actual production (i.e., in the actual production of Lyocell fiber, hereinafter simply referred to as large-scale production), a falling film evaporator or a multi-effect evaporator is usually used to evaporate and concentrate the NMMO aqueous solution. Both the falling film evaporator and the multi-effect evaporator are medium and large-sized equipment, and each time they can concentrate more than 1 ton of NMMO aqueous solution. In existing laboratories, a rotary evaporator is usually used to evaporate and concentrate the NMMO aqueous solution, and the processing capacity of the existing rotary evaporator is relatively low, and the amount that can be concentrated each time usually does not exceed 2 Kg.

[0004] For non-Lyocell fiber production enterprises or NMMO solution production enterprises, to concentrate 10 - 50 kg / time of NMMO aqueous solution for Lyocell fiber pilot experiments, neither of the above two types of equipment is suitable, and the existing technology also lacks an evaporation and concentration equipment that can meet the Lyocell fiber pilot experiments, which urgently needs to be solved. Summary of the Invention

[0005] The first aspect of the utility model aims to solve the above technical problems and provides an evaporation concentrator that can evaporate and concentrate 10 - 50 kg of NMMO solution each time, which well meets the requirements of Lyocell fiber pilot experiments. The main concept is as follows:

[0006] A novel NMMO solvent evaporation concentrator includes a concentration tank, and a concentration chamber is constructed inside the concentration tank.

[0007] A stirrer, the stirrer includes a motor, a vertically arranged stirring shaft, and blades arranged in the concentration chamber. The motor is in transmission connection with the stirring shaft and is used to drive the stirring shaft to rotate. The lower end of the stirring shaft extends into the concentration chamber, and the blades are connected to the stirring shaft. And

[0008] Liquid distributor, the liquid distributor is arranged in the concentration chamber and above the paddle. The liquid distributor includes an outer cylinder adapted to the concentration chamber and a grid structure arranged in the outer cylinder. An ascending channel is formed between the outer cylinder and the grid structure. The upper end of the outer cylinder is configured with a guiding portion for guiding the liquid to shift towards the center of the concentration chamber and then fall back to the grid structure. In this solution, by configuring the concentration chamber, a place is provided for the evaporation and concentration process of the NMMO solution; by configuring the stirrer, the rotation of the paddle in the stirrer is used to cause the NMMO solution in the concentration chamber to form a vortex, so that the NMMO solution can rise along the tank wall under the action of centrifugal force; by configuring the liquid distributor and arranging the outer cylinder and the grid structure in it, an ascending channel can be formed between the outer cylinder and the grid structure, so that the solution rising along the tank wall can continue to rise through the ascending channel, and the liquid distributor will not block the rising solution; by configuring the guiding portion, the solution rising through the ascending channel can be guided by the guiding portion to shift towards the center of the concentration chamber. After reaching the highest point, the solution can fall downward under the action of its own gravity and just land on the grid structure. Through the grid structure, a liquid film and a large number of liquid particles (droplets) are formed, and finally they are re-incorporated into the NMMO solution below. By circulating in this way, the surface area of the liquid can be greatly increased, which is conducive to quickly evaporating the water in the NMMO solution in a vacuum (negative pressure) state, achieving the purpose of efficiently concentrating the NMMO solution. Compared with the existing equipment, the amount of liquid that can be concentrated by this evaporation concentrator each time is more than that of a rotary evaporator, reaching 10 to 50 kilograms, which is suitable for the amount of the pilot production of Lyocell fibers; moreover, the concentration efficiency of this evaporation concentrator is higher than that of a rotary evaporator and is equivalent to that of a multi-effect evaporator, but the volume and cost are only 1 / 100 of those of a multi-effect evaporator, making this evaporation concentrator very meet the requirements of the pilot experiment of Lyocell fibers.

[0009] Furthermore, the grid structure is arranged at the middle position of the outer cylinder. An annular ascending channel is formed between the grid structure and the outer cylinder. The grid structure is connected to the outer cylinder through a number of connecting pieces. By configuring the connecting pieces, the grid structure can be fixed to the outer cylinder by using the connecting pieces; by arranging the grid structure at the middle position of the outer cylinder, an annular ascending channel is formed between the grid structure and the outer cylinder, which can not only better adapt to the solution rising along the tank wall, but also effectively increase the area of the ascending channel, which is more conducive to the solution below to pass upward through the liquid distributor.

[0010] In the second aspect of the present utility model, the problem of further improving the evaporation and concentration efficiency is to be solved. Preferably, the grid structure includes at least two coaxially arranged grid cylinders, and a plurality of radially arranged grid plates are provided between adjacent grid cylinders. The inner diameter of the innermost grid cylinder is larger than the outer diameter of the stirring shaft. By configuring at least two coaxially arranged grid cylinders in the grid structure and providing a plurality of radially arranged grid plates between adjacent grid cylinders, a relatively dense grid mesh can be formed, so that the falling solution can be better divided by the grid structure, and the solution can form a liquid film and a large number of droplets when passing through the grid structure, thereby greatly increasing the surface area of the liquid and achieving the purpose of efficient evaporation and concentration.

[0011] Preferably, the grid structure includes three coaxially arranged grid cylinders.

[0012] Preferably, the height of the innermost grid cylinder is greater than the height of the outer grid cylinder. This is more conducive to guiding the falling solution to pass through the grid structure.

[0013] Preferably, each connecting member is respectively connected to the outermost grid cylinder, and each connecting member is evenly arranged along the radial direction of the grid cylinder. This is to support the grid structure more stably.

[0014] Preferably, the connecting member is in a plate-like structure or a rod-like structure. This is to minimize the blockage during the upward movement of the solution, so that the solution rising under the action of centrifugal force can rise higher, thereby being more conducive to evaporating water.

[0015] In the third aspect of the present utility model, the problem of guiding the rising liquid to shift towards the center of the concentration chamber is to be solved. Preferably, the guiding part is a guiding cylinder constructed at the upper end of the outer cylinder and inclined inward. Thus, the inwardly inclined guiding cylinder can be used to guide the rising solution to shift towards the center of the concentration chamber, so as to move above the grid structure and then smoothly fall into the lower grid structure subsequently.

[0016] Preferably, the included angle between the guiding cylinder and the outer cylinder is 140° - 170°. This is conducive to achieving a better guiding effect and ensuring that the solution guided by the guiding cylinder can exactly fall into the lower grid structure.

[0017] Furthermore, the concentration tank is also provided with a vacuum connector, and the vacuum connector is communicated with the concentration chamber. This is to keep the concentration tank in a vacuum (negative pressure) state during use. The vacuum (negative pressure) condition is conducive to the water in the solution evaporating into water vapor and being pumped away at a temperature below 100°C, achieving the purpose of only evaporating water without evaporating the solvent.

[0018] Furthermore, a discharge port is also constructed at the bottom of the concentration tank. This is to automatically discharge the evaporated and concentrated NMMO solution outward through the discharge port by the action of gravity.

[0019] In the fourth aspect of the present utility model, the problem of improving the stability of the stirring shaft during operation is to be solved. Further, it further includes a bearing seat. The lower end of the stirring shaft is connected to the bearing seat through a bearing, and the bearing seat is fixed to the bottom of the concentration tank. Thus, the lower end of the stirring shaft can be effectively constrained by the bearing seat, making the stirring shaft more stable during rotation.

[0020] Preferably, a bearing hole is formed at the upper end of the bearing seat, a central hole is formed at the lower end of the bearing seat, and a plurality of diversion holes communicating with the central hole are formed on the side surface of the bearing seat. The lower end of the bearing seat is fixed to the bottom of the concentration tank, and the discharge port formed at the bottom of the concentration tank is communicated with the central hole. By adopting this bearing seat, the stirring shaft can be supported more stably to ensure that the stirring shaft rotates along its center line, and at the same time, it can ensure that the solution in the concentration tank can be discharged through the discharge port at the bottom of the concentration tank.

[0021] In the fifth aspect of the present utility model, the problem of further improving the evaporation efficiency is to be solved. Further, the concentration tank includes a tank body and a tank cover. The concentration chamber is formed in the tank body, and the upper end of the tank body is open. The tank cover is detachably installed on the tank body and closes the opening. A jacket is further covered outside the tank body. A heating chamber for heating the tank body is formed between the jacket and the tank body. The jacket is also provided with an inlet and an outlet, and the inlet and the outlet are respectively communicated with the heating chamber. So as to inject hot water at a set temperature into the heating chamber. After the hot water fills the heating chamber, it is discharged through the outlet. During this process, the hot water continuously heats the tank body, thereby heating the solution in the tank body, and finally achieving the purpose of improving the evaporation efficiency.

[0022] Further, a spiral partition strip is further provided in the heating chamber, and the spiral partition strip divides a spiral channel in the heating chamber. So as to effectively increase the flow path of the hot water by using the spiral channel, improve the residence time of the hot water, and thus can further improve the heat transfer efficiency and achieve a better heating effect.

[0023] Further, it further includes a feeding cover. A feeding port is also provided on the tank cover, and the feeding cover is detachably and sealingly connected to the feeding port.

[0024] Further, a valve and a vacuum joint are also provided on the feeding cover. The valve is used to control the on-off between the vacuum joint and the concentration chamber. So that the vacuum joint can be communicated with the concentration chamber through the feeding port, which is beneficial to reducing the number of holes opened on the tank cover, reducing costs and improving the strength of the tank cover.

[0025] Compared with the prior art, a novel NMMO solvent evaporation concentrator provided by the present utility model has a higher concentration efficiency than a rotary evaporator and is comparable to that of a multi-effect evaporator. However, its volume and cost are only 1 / 100 of those of a multi-effect evaporator. Moreover, the amount of liquid that can be concentrated by this evaporation concentrator each time is more than that of a rotary evaporator, reaching 10 to 50 kilograms, which well meets the requirements of the pilot experiment of Lyocell fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 The front view of a liquid distributor in an evaporation concentrator provided by an embodiment of the present utility model.

[0028] Figure 2 The sectional view of a liquid distributor in an evaporation concentrator provided by an embodiment of the present utility model.

[0029] Figure 3 For Figure 1 the bottom view.

[0030] Figure 4 The structural schematic diagram of an evaporation concentrator provided by an embodiment of the present utility model.

[0031] Figure 5 For Figure 4 the partial enlarged schematic diagram at I in

[0032] Figure 6 For Figure 4 the partial enlarged schematic diagram at II in

[0033] Figure 7 The partial sectional view of the concentration chamber when evaporating and concentrating the NMMO solution by using the evaporation concentrator provided by the embodiment of the present utility model.

[0034] Marking description in the figure: Concentrating tank 1, tank body 11, concentrating chamber 111, flange 112, discharge port 113, tank cover 12, support 121, feeding port 122, internal thread 123, sealing ring 124, feeding cover 13, external thread 131, support structure 14; agitator 2, motor 21, coupling 22, stirring shaft 23, paddle 24; bearing seat 3, bearing hole 31, central hole 32, diversion hole 33; liquid distributor 4, outer cylinder 41, connecting piece 42, grid structure 43, grid cylinder 44, grid plate 45, rising channel 46, guiding cylinder 47; mechanical seal 51, bearing 52, fastener 53; jacket 6, heating chamber 61, spiral partition 62, inlet 63, outlet 64, valve 65; frame 7; liquid level 8. Detailed implementation manners

[0035] 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 following 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 claimed, but merely 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.

[0036] Embodiment 1

[0037] Please refer to Figure 1 , a new type of NMMO solvent evaporation concentrator is provided in this embodiment, including a concentrating tank 1, an agitator 2 and a liquid distributor 4. Among them,

[0038] A concentrating chamber 111 is constructed inside the concentrating tank 1. During implementation, the concentrating tank 1 can be an integral structure. However, in a preferred implementation manner, the concentrating tank 1 includes a tank body 11 and a tank cover 12. As Figure 4 shown, the concentrating chamber 111 is constructed in the tank body 11, and the upper end of the tank body 11 is open. The tank cover 12 is detachably installed on the tank body 11 and closes the opening. During implementation, a flange 112 is constructed at the upper end of the tank body 11. At the same time, a matching flange 112 is also constructed on the tank cover 12, so that the tank cover 12 can be detachably connected to the tank body 11 through the fastener 53 of the matching flange 112, as Figure 4 shown. In addition, to improve the sealing performance, a sealing gasket can also be arranged between the two flanges 112.

[0039] In this embodiment, the stirrer 2 includes a motor 21, a vertically arranged stirring shaft 23, and a paddle 24 disposed in the concentration chamber 111. Among them, the motor 21 can be fixed to the bracket 121, and the bracket 121 can be fixed to the tank cover 12, as Figure 4 shown, or it can be fixed on other supporting bases. The motor 21 can be drivingly connected to the upper end of the stirring shaft 23 through a coupling 22, so as to drive the stirring shaft 23 to rotate by using the motor 21, as Figure 4 shown. During implementation, a communication hole for passing through the stirring shaft 23 is formed at the central position of the tank cover 12, and the lower end of the stirring shaft 23 can extend into the concentration chamber 111 through this communication hole, as Figure 4 shown. At the same time, a mechanical seal 51 is also provided at the communication hole to improve the sealing performance at the communication hole and prevent external air from entering the tank body 11 along the stirring shaft 23. It can be understood that during implementation, the mechanical seal 51 can be realized by using existing technologies and will not be elaborated here.

[0040] As Figure 4 shown, the paddle 24 is connected to the stirring shaft 23 so as to rotate under the drive of the stirring shaft 23, thereby achieving the purpose of stirring the NMMO solution in the concentration chamber 111. During implementation, for the convenience of assembly, the stirring shaft 23 can adopt a stepped shaft, and the paddle 24 can be fixed to the stirring shaft 23 through a fastener 53 or welded to the stirring shaft 23. During implementation, the number of the paddles 24 can be determined according to actual needs, and one paddle 24, two paddles 24, three paddles 24, etc. can be configured.

[0041] For the convenience of use, the concentration tank 1 is also configured with a feeding port 122 and a vacuum joint. The feeding port 122 and the vacuum joint are respectively communicated with the concentration chamber 111, so as to add the NMMO solution into the tank body 11 through the feeding port 122, and a vacuum pumping device can be connected through the vacuum joint, so that during use, the concentration tank 1 can maintain a vacuum (negative pressure) state. The vacuum (negative pressure) condition is conducive to the water in the solution evaporating into water vapor at a temperature lower than 100 °C and being pumped away, achieving the purpose of only evaporating water without evaporating the solvent.

[0042] During implementation, the feeding port 122 and the vacuum joint can be respectively arranged on the tank cover 12. To seal the feeding port 122, during implementation, this evaporation concentrator is also configured with a feeding cover 13, as Figure 4 and Figure 5 shown. The feeding cover 13 is detachably and sealingly connected to the feeding port 122. For example, during implementation, the feeding port 122 is configured with an internal thread 123, and the feeding cover 13 is configured with an external thread 131 adapted to the internal thread 123, so that the feeding cover 13 can be threadedly connected to the feeding port 122, as Figure 5As shown. In addition, during implementation, an annular sealing groove is formed at the end of the feeding port 122, and a sealing ring 124 is arranged in the sealing groove, so that the sealing ring 124 can be pressed by the feeding cover 13, as Figure 5 shown, to achieve the purpose of sealing and ensure no air leakage. In another implementation manner, the feeding cover 13 is further provided with a channel. The vacuum connector can be connected to the feeding cover 13 and communicated with the channel, and a valve is arranged between the vacuum connector and the feeding cover 13, so as to control the on-off of the vacuum connector and the concentration chamber 111 by using the valve, so that the vacuum connector can be communicated with the concentration chamber 111 through the feeding port 122, thereby reducing the number of openings on the tank cover 12, being beneficial to reducing costs and improving the strength of the tank cover 12.

[0043] During implementation, a discharge port 113 is further formed at the bottom of the concentration tank 1, as Figure 4 shown, so as to automatically discharge the evaporated and concentrated NMMO solution outward through the discharge port 113 by the action of gravity. During implementation, the lower end of the stirring shaft 23 can be in a suspended state. To improve the stability of the stirring shaft 23 during operation, in a further implementation manner, a bearing seat 3 is further included. The lower end of the stirring shaft 23 can be connected to the bearing seat 3 through a bearing 52, and the bearing seat 3 is fixed to the bottom of the concentration tank 1, so that the lower end of the stirring shaft 23 can be effectively constrained by the bearing seat 3, making the stirring shaft 23 more stable during rotation. Since the discharge port 113 is fixed to the bottom of the tank body 11, if the bearing seat 3 is also fixed to the bottom of the tank body 11, the discharge port 113 will be blocked. Therefore, in one implementation manner, the discharge port 113 can be arranged at a position deviating from the center of the tank body 11 at the bottom of the tank body 11, so that the discharge port 113 and the bearing seat 3 do not interfere with each other, but it is not conducive to draining the solution in the tank body 11 through the discharge port 113. In another implementation manner, a bearing 52 hole 31 is formed at the upper end of the bearing seat 3 for installing the bearing 52, as Figure 4 and Figure 6 shown. At the same time, a central hole 32 is formed at the lower end of the bearing seat 3, as Figure 6 shown, and a plurality of diversion holes 33 communicating with the central hole 32 are formed on the side surface of the bearing seat 3; at this time, as Figure 4 and Figure 6 shown, the lower end of the bearing seat 3 can be fixed to the bottom of the concentration tank 1, and the discharge port 113 formed at the bottom of the concentration tank 1 is communicated with the central hole 32, as Figure 6 shown. With such a structure, not only can the stirring shaft 23 be supported more stably to ensure that the stirring shaft 23 rotates along its center line, but also the solution in the concentration tank 1 can be discharged through the discharge port 113 at the bottom of the concentration tank 1.

[0044] In this embodiment, the liquid distributor 4 is arranged in the concentration chamber 111 and above the paddle 24, as Figure 4As shown, so as to form an up-and-down cooperation with the blade 24. In this embodiment, the liquid distributor 4 includes an outer cylinder 41 adapted to the concentration chamber 111 and a grid structure 43 disposed inside the outer cylinder 41. Among them, the shape of the outer cylinder 41 can be adapted to the cross-sectional shape of the concentration chamber 111. For example, in this embodiment, the cross-sectional shape of the concentration chamber 111 can be circular, and correspondingly, the outer cylinder 41 can also be constructed as a cylindrical barrel; at the same time, the size of the outer cylinder 41 can also be adapted to the cross-sectional size of the concentration chamber 111. For example, in this embodiment, the outer diameter of the outer cylinder 41 can be slightly smaller than the inner diameter of the concentration chamber 111, which is convenient for assembly and makes the outer cylinder 41 closer to the tank wall of the tank body 11, as Figure 4 shown.

[0045] As Figures 1 - 4 shown, an ascending channel 46 is formed between the outer cylinder 41 and the grid structure 43, so that the solution rising along the tank wall can continue to rise from the ascending channel 46, and the liquid distributor 4 will not block the rising solution. During implementation, the grid structure 43 can be disposed at the middle position of the outer cylinder 41, as Figure 4 shown, so that an annular ascending channel 46 can be formed between the grid structure 43 and the outer cylinder 41, which can not only better adapt to the solution rising along the tank wall, but also effectively increase the area of the ascending channel 46, which is more conducive to the solution below to pass upward through the liquid distributor 4.

[0046] As Figures 1 - 4 shown, the grid structure 43 can be connected to the outer cylinder 41 through a number of radially arranged connecting members 42, so as to fix the grid structure 43 to the outer cylinder 41 by using the connecting members 42. During implementation, the connecting members 42 can adopt a plate-like structure or a rod-like structure, etc., so as to minimize the blockage during the rising process of the solution, as Figures 1 - 4 shown, so that the solution rising under the action of centrifugal force can rise higher, which is more conducive to evaporating water.

[0047] In this embodiment, the grid structure 43 includes at least two coaxially arranged grid cylinders 44, and a plurality of radially arranged grid plates 45 are arranged between adjacent two grid cylinders 44, as Figures 1 - 4 shown, so as to form a relatively dense grid mesh, so that the grid structure 43 can better divide the falling solution, so that the solution can form a liquid film and a large number of liquid droplets when passing through the grid structure 43, thereby greatly increasing the surface area of the liquid and achieving the purpose of efficient evaporation and concentration. During implementation, the inner diameter of the innermost grid cylinder 44 is larger than the outer diameter of the stirring shaft 23, as Figure 2 and Figure 4 shown, so that the stirring shaft 23 can smoothly pass through the liquid distributor 4.

[0048] In implementation, the number of the grid cylinders 44 can be determined according to actual requirements. For example, the number of the grid cylinders 44 can be two, three, four, etc. As an example, the grid structure 43 includes three coaxially arranged grid cylinders 44. As Figures 2 - 4 shown, a plurality of radially arranged grid plates 45 are provided between two adjacent grid cylinders 44. Moreover, the height of the innermost grid cylinder 44 can be greater than that of the outer grid cylinders 44, which is more conducive to guiding the falling solution to pass through the grid structure 43.

[0049] In implementation, each connecting member 42 can be respectively connected to the outermost grid cylinder 44. As Figures 2 - 4 shown, and each connecting member 42 can be respectively arranged uniformly along the radial direction of the grid cylinder 44 so as to support the grid structure 43 more stably. In implementation, the liquid distributor 4 can be welded inside the tank body 11. However, in a preferred implementation manner, a support structure 14 for supporting the liquid distributor 4 is further provided on the tank wall of the concentration tank 1. As Figure 4 shown, the support structure 14 can be a support ring or at least two support seats arranged along the circumferential direction, so as to support the liquid distributor 4 by means of the support structure 14. This can not only fix the liquid distributor 4, but also facilitate the installation, disassembly and replacement of the liquid distributor 4. In a more perfect implementation manner, a plurality of lugs are further provided on the outer cylinder 41 of the liquid distributor 4, and the lugs are provided with a plurality of threaded holes so as to fix the lugs to the support structure 14 by means of fasteners 53, thereby effectively fixing the entire liquid distributor 4.

[0050] In this embodiment, a guiding portion for guiding the liquid to deflect towards the center of the concentration chamber 111 and then fall back to the grid structure 43 is further constructed at the upper end of the outer cylinder 41. As Figures 1 - 4 shown, the solution rising along the rising channel 46 can deflect towards the center of the concentration chamber 111 under the guidance of the guiding portion. After reaching the highest point, the solution can fall downward under the action of its own gravity and just land on the grid structure 43, forming a liquid film and a large number of liquid particles (droplets) through the grid structure 43, and finally re-merging into the NMMO solution below. In this way, the cycle is carried out. As Figure 7 shown, the surface area of the liquid can be greatly increased, so as to facilitate the rapid evaporation of the water in the NMMO solution in a vacuum (negative pressure) state and achieve the purpose of efficiently concentrating the NMMO solution. In implementation, the guiding portion has various implementation manners. For example, in the preferred implementation manner provided in this embodiment, the guiding portion can be a guiding cylinder 47 constructed at the upper end of the outer cylinder 41 and inclined inward. As Figures 1 - 4As shown, the inwardly inclined guiding cylinder 47 can be used to guide the rising solution to shift towards the center of the concentration chamber 111, so as to move above the grid structure 43, and thus can smoothly fall into the lower grid structure 43 subsequently. In implementation, the guiding cylinder 47 can adopt a straight cylinder, that is, the inner diameter of one end of the guiding cylinder 47 is large and the inner diameter of the other end is small. In the direction from the large end to the small end, the cross-section of the guiding cylinder 47 is a linear structure, such as Figure 1 and Figure 2 shown. The inclination angle of the guiding cylinder 47 can be determined according to actual needs. However, in order to achieve a better guiding effect, the included angle θ between the guiding cylinder 47 and the outer cylinder 41 can be 140 - 170°, such as Figure 2 shown. This is not only conducive to achieving a better guiding effect, but also can ensure that the solution guided by the guiding cylinder 47 can exactly fall into the lower grid structure 43. In addition, in other implementation manners, the guiding cylinder 47 can also adopt an arc-shaped cylinder, and the same effect can be achieved.

[0051] such as Figures 1 - 4 shown. The position of the guiding part is higher than the grid structure 43, and the guiding part can better cooperate with the grid structure 43. In implementation, the guiding part and the outer cylinder 41 can be an integral structure, or the guiding part can be fixed to the outer cylinder 41 by means such as welding and bolt connection. Examples are not given one by one here.

[0052] In a more perfect solution, it further includes a frame 7. The tank body 11 can be fixed to the frame 7 and the tank body 11 is in a suspended state, such as Figure 4 shown.

[0053] Embodiment 2

[0054] To further improve the evaporation efficiency of the evaporation concentrator, the main difference between this Embodiment 2 and the above Embodiment 1 is that in the evaporation concentrator provided in this embodiment, a jacket 6 is further covered outside the tank body 11, such as Figure 4 shown, so that a heating chamber 61 for heating the tank body 11 can be formed between the jacket 6 and the tank body 11. At the same time, the jacket 6 is also provided with an inlet 63 and an outlet 64. The inlet 63 and the outlet 64 are respectively communicated with the heating chamber 61. The inlet 63 and the outlet 64 are respectively provided with connecting pipes so as to connect to the external pipelines by using the connecting pipes. At the same time, a valve 65 is provided on the connecting pipe, such as Figure 4 shown, so as to control the on-off of the inlet 63 and the outlet 64 through the valve 65.

[0055] During use, hot water at a set temperature can be injected into the heating chamber 61 from the inlet 63. After the hot water fills the heating chamber 61, it is discharged through the outlet 64. In this process, the hot water continuously heats the tank body 11, thereby heating the solution in the tank body 11, and finally achieving the purpose of improving the evaporation efficiency.

[0056] In a further embodiment, a spiral partition strip 62 is further disposed in the heating chamber 61. As Figure 4 shown, the spiral partition strip 62 can partition a spiral channel in the heating chamber 61. As Figure 4 shown, the spiral channel can be effectively used to increase the flow path of the hot water, improve the residence time of the hot water, and further improve the heat transfer efficiency, thereby achieving a better heating effect.

[0057] When using this evaporation concentrator, the tank body 11 is filled with NMMO liquid solvent, and its liquid level is higher than the paddle 24 and lower than the bottom end of the liquid distributor 4. The motor 21 is started and drives the paddle 24 to rotate. The solution in the tank body 11 rises along the tank wall under the action of centrifugal force, and rises along the rising channel 46 of the liquid distributor 4. Under the guiding action of the guiding part, the solution synchronously shifts towards the center of the concentration chamber 111 while rising. After reaching the highest point, the solution is already above the grid structure 43. At this time, the solution can fall downward under the action of its own gravity and just fall on the grid structure 43, forming a liquid film and a large number of liquid particles (droplets) through the grid structure 43, and finally re-merging into the NMMO solution below. This process repeats continuously, as Figure 4 and Figure 7 shown. During this process, the tank body 11 is evacuated by a vacuum device, so that the concentration chamber 111 in the tank body 11 maintains a vacuum (negative pressure) state, and the water in the solution evaporates into water vapor at a temperature lower than 100°C and is pumped away. At the same time, hot water is injected into the heating chamber 61 of the jacket 6. The heating effect of the hot water on the tank body 11 raises the temperature of the internal solution, causing the water in the NMMO solution to continuously evaporate. With the continuous rotation of the stirrer 2, the solution circulates from bottom to top, is heated, forms a film and falls back to evaporate water, and the concentration of the NMMO solution becomes higher and higher, reaching the process set requirements. Finally, after confirming that the concentration meets the requirements, the stirring rotation is stopped and the vacuum device is disconnected, and the solution in the tank is discharged through the discharge port 113 to obtain the evaporated and concentrated NMMO solution.

[0058] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all should be covered by the protection scope of the present invention.

Claims

1. A new type of NMMO solvent evaporation concentrator, characterized in that, It includes a concentration tank, and a concentration chamber is configured inside the concentration tank. A stirrer, the stirrer includes a motor, a vertically arranged stirring shaft, and blades disposed in the concentration chamber. The motor is drivingly connected to the stirring shaft for driving the stirring shaft to rotate. The lower end of the stirring shaft extends into the concentration chamber, and the blades are connected to the stirring shaft, and A liquid distributor, the liquid distributor is disposed in the concentration chamber and above the blades. The liquid distributor includes an outer cylinder adapted to the concentration chamber and a grid structure disposed inside the outer cylinder. An upward channel is formed between the outer cylinder and the grid structure, and a guiding portion for guiding the liquid to shift towards the center of the concentration chamber and fall back to the grid structure is configured at the upper end of the outer cylinder.

2. The novel NMMO solvent evaporation concentrator according to claim 1, wherein, The grid structure is disposed at the middle position of the outer cylinder. An annular upward channel is formed between the grid structure and the outer cylinder, and the grid structure is connected to the outer cylinder through a plurality of connecting members.

3. The novel NMMO solvent evaporation concentrator according to claim 2, characterized in that, The grid structure includes at least two coaxially arranged grid cylinders. A plurality of radially arranged grid plates are disposed between adjacent grid cylinders, and the inner diameter of the innermost grid cylinder is larger than the outer diameter of the stirring shaft.

4. The novel NMMO solvent evaporation concentrator according to claim 3, wherein The grid structure includes three coaxially arranged grid cylinders; and / or, the height of the innermost grid cylinder is greater than the height of the outer grid cylinders.

5. The novel NMMO solvent evaporation concentrator according to claim 3, characterized in that, Each connecting member is respectively connected to the outermost grid cylinder, and each connecting member is uniformly arranged along the radial direction of the grid cylinder; and / or, the connecting member is a plate-like structure or a rod-like structure.

6. The novel NMMO solvent evaporation concentrator according to claim 1, wherein The guiding portion is a guiding cylinder configured at the upper end of the outer cylinder and inclined inward.

7. The novel NMMO solvent evaporation concentrator according to claim 6, wherein The included angle between the guiding cylinder and the outer cylinder is 140° to 170°.

8. The novel NMMO solvent evaporation concentrator according to claim 1, characterized in that, It further includes a bearing seat. The lower end of the stirring shaft is connected to the bearing seat through a bearing, and the bearing seat is fixed to the bottom of the concentration tank; A bearing hole is configured at the upper end of the bearing seat, a central hole is configured at the lower end of the bearing seat, and a plurality of diversion holes communicating with the central hole are configured on the side surface of the bearing seat. The lower end of the bearing seat is fixed to the bottom of the concentration tank, and a discharge port configured at the bottom of the concentration tank is connected to the central hole.

9. The novel NMMO solvent evaporation concentrator according to claim 1, wherein, The concentration tank includes a tank body and a tank cover. The concentration chamber is configured in the tank body, and the upper end of the tank body is open. The tank cover is detachably installed on the tank body and closes the opening; A jacket is further wrapped outside the tank body. A heating chamber for heating the tank body is formed between the jacket and the tank body. The jacket is also provided with an inlet and an outlet, and the inlet and the outlet are respectively connected to the heating chamber.

10. The novel NMMO solvent evaporation concentrator according to claim 9, characterized in that, A spiral partition strip is further disposed in the heating chamber, and the spiral partition strip divides a spiral channel in the heating chamber; and / or, a discharge port is further configured at the bottom of the concentration tank; and / or, it further includes a feeding cover. A feeding port is further provided on the tank cover, and the feeding cover is detachably and sealingly connected to the feeding port. A valve and a vacuum joint are further provided on the feeding cover, and the valve is used to control the on-off between the vacuum joint and the concentration chamber.

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