Horizontal crushing and mixing device for producing cellulose pulp porridge

Abstract

The invention belongs to the technical field of crushing and mixing devices, and relates to a horizontal crushing and mixing device for producing cellulose pulp porridge, the horizontal crushing and mixing device comprises a mixing cylinder and a stirrer coaxially mounted in the mixing cylinder, and the cylinder body of the mixing cylinder is of a reducing structure; the mixing cylinder is formed by sequentially connecting a large cylinder, a circular-truncated-cone-shaped cylinder and a small cylinder which are horizontally placed and coaxial, the diameter of the large end of the circular-truncated-cone-shaped cylinder is equal to that of the large cylinder, and the diameter of the small end of the circular-truncated-cone-shaped cylinder is equal to that of the small cylinder; a cellulose particle inlet is formed in the position, away from the circular-truncated-cone-shaped barrel, of the large cylinder, an NMMO aqueous solution inlet is formed in the position, close to the circular-truncated-cone-shaped barrel, of the large cylinder, and a cellulose pulp porridge outlet is formed in the position, away from the circular-truncated-cone-shaped barrel, of the small cylinder. According to the invention, cellulose particles and an NMMO aqueous solution can be uniformly mixed, the cellulose particles are fully swelled, the solution is prevented from quickly flowing out from the material outlet, and the utilization rate of the solution is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of crushing and mixing devices, and relates to a horizontal crushing and mixing device for producing cellulose pulp porridge. Background Art

[0002] In modern industry, crushing and mixing devices are widely used in various industrial fields. Crushing efficiency and mixing uniformity are important technical indicators for evaluating mixing devices. At the same time, the reliability of the equipment is closely related to the economic benefits and personal safety of the enterprise, and is also a very important issue.

[0003] Lyocell fiber is known as the green fiber of the 21st century and will be a substitute for viscose fiber, protein fiber and other fibers in the future. It is a regenerated cellulose fiber spun by dry and wet methods using NMMO as solvent. The preparation of spinning solution is the most critical process in the production of lyocell fiber, and the pre-mixing effect of cellulose pulp and NMMO aqueous solution is the key to dissolution. If the mixing is uneven, it will also bring difficulties to the subsequent dissolution, spinning and other processes, thereby affecting the product quality of lyocell fiber.

[0004] At present, there are two types of pre-mixers used in the production process of lyocell fibers: vertical mixers and horizontal mixers. Compared with vertical mixers, horizontal mixers can realize the continuous preparation of cellulose pulp porridge. The quality of cellulose pulp porridge prepared in different batches is continuous and stable. At the same time, the process conditions of horizontal mixers are easy to control, maintain and clean. Therefore, they are more widely used. However, the mixing barrel of the horizontal mixer commonly used in the prior art is of equal diameter. When using this mixing device to mix materials, there will be problems such as low crushing efficiency, uneven mixing, insufficient swelling of cellulose particles, and rapid outflow of solution. For example, patents CN202211195173.4, CN202223132275.X, CN202211195173.4, CN201621421360.X, etc., the mixing barrels all adopt equal diameter structures. Therefore, when used to produce cellulose pulp porridge, when the NMMO aqueous solution is injected from the liquid inlet, the NMMO aqueous solution will flow out quickly from the material outlet, resulting in a waste of solution.

[0005] The mixing barrel of patent 201510542825.0 also adopts an equal diameter structure. This patent solves the problem of insufficient contact and short contact time between cellulose particles and NMMO aqueous solution caused by the rapid outflow of NMMO aqueous solution from the material outlet by adding baffles. However, it will affect the uniformity of mixing and the quality of the final product, and will bring problems in installation and maintenance. First, although the addition of baffles alleviates the problem of rapid outflow of liquid to a certain extent, it may also lead to the phenomenon of "dead zone" in the mixing process, that is, due to the obstruction of the baffle, the material cannot flow and mix fully in some areas, thereby affecting the overall mixing uniformity and the quality of the final product; secondly, the complex baffle design and the related sliding adjustment mechanism, positioning structure, etc., not only increase the manufacturing and installation costs of the equipment, but also increase the difficulty of subsequent maintenance and adjustment. In particular, the sliding adjustment mechanism may not be installed due to the design or the small inner diameter of the barrel, and the liquid flow rate and liquid level cannot be effectively adjusted. The easy "stuck" phenomenon of components such as racks and bevel gears will also significantly reduce the overall reliability and stability of the equipment. In addition, although the "liquid storage tank" structure formed by the baffle solved the problem of short contact time, it did not effectively increase the contact area of ​​the material, and also resulted in the swelling and mixing efficiency of the cellulose particles not being improved.

[0006] Therefore, it is of great significance to study a horizontal crushing and mixing device for producing cellulose pulp to solve the above problems. Summary of the invention

[0007] The purpose of the present invention is to solve the problems existing in the prior art and to provide a horizontal crushing and mixing device for producing cellulose pulp.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A horizontal crushing and mixing device for producing cellulose porridge comprises a mixing drum and a stirrer installed in the mixing drum in a coaxial manner, wherein the drum body of the mixing drum is a variable diameter structure;

[0010] The mixing cylinder is composed of a large cylindrical cylinder, a truncated cone cylinder and a small cylindrical cylinder which are placed horizontally and coaxially and connected in sequence. The diameter of the large end of the truncated cone cylinder is equal to the diameter of the large cylindrical cylinder, and the diameter of the small end of the truncated cone cylinder is equal to the diameter of the small cylindrical cylinder.

[0011] A cellulose particle inlet is provided on the large cylindrical cylinder at a position away from the truncated cone-shaped cylinder, an NMMO aqueous solution inlet is provided on the large cylindrical cylinder at a position close to the truncated cone-shaped cylinder, and a cellulose slurry outlet is provided on the small cylindrical cylinder at a position away from the truncated cone-shaped cylinder;

[0012] The stirrer comprises a stirring shaft and a stirring blade fixed on the stirring shaft, and the stirring blade is a spiral blade;

[0013] The mixing cylinder and the spiral blades cooperate with each other to form a relatively closed stirring area to stir the cellulose particles and the NMMO aqueous solution, so that the cellulose particles fully absorb the NMMO aqueous solution and fully swell.

[0014] The horizontal crushing and mixing device of the present invention is mainly used for generating cellulose pulp porridge, wherein the solid material is cellulose particles (or approximately round particles) with a diameter of 3-4 mm, and the liquid material is NMMO aqueous solution; 9-12% (mass ratio) of cellulose particles are swollen, crushed and stirred in the NMMO aqueous solution to uniformly mix, and the prepared high-concentration cellulose suspension is the cellulose pulp porridge.

[0015] like Figure 5 As shown in the figure, the square box represents a square trough filled with NMMO aqueous solution. ① At 0 seconds, dry cellulose particles are put into the square trough filled with NMMO aqueous solution. At this time, the cellulose particles have not absorbed the NMMO aqueous solution, and the dry cellulose particles that have not absorbed the NMMO aqueous solution are represented by all-black circles; ② At t1 seconds, the NMMO aqueous solution penetrates into the interior of the cellulose particles, so the area of ​​the dry cellulose particles in the middle that have not absorbed the NMMO aqueous solution continues to shrink, the small black circle in the middle represents the area of ​​the dry cellulose particles that have not absorbed the NMMO aqueous solution, and the transparent part between the small circle and the large circle represents the area of ​​the cellulose particles that have absorbed the NMMO aqueous solution. At this time, the area of ​​the entire cellulose particle is larger than that at 0 seconds; ③ At t2 seconds, the cellulose particles are completely filled with the NMMO aqueous solution, and the small black circle inside that represents the surface of the dry cellulose particles completely disappears, and the area of ​​the entire cellulose particle is further increased than that at t1 seconds; ④ At 60 seconds, the area of ​​the cellulose particles is further increased under the action of the NMMO aqueous solution.

[0016] like Figure 6As shown in FIG. 1 , the swelling process of cellulose particles in the prior art equal-diameter mixing cylinder is as follows: ① at 0 seconds, dry cellulose particles are put into the tank containing the NMMO aqueous solution, but only a small part of the volume of the cellulose particles is in contact with the NMMO aqueous solution, because the NMMO aqueous solution tends to flow to the material outlet on the right; ② from 0 to t1 seconds, part of the NMMO aqueous solution penetrates into the interior of the cellulose particles, and the black circle in the middle represents the area of ​​the dry cellulose particles that have not absorbed the NMMO aqueous solution, and the transparent part between the small circle and the large circle represents the area of ​​the cellulose particles that have absorbed the NMMO aqueous solution. 1. The cellulose particles are not fully in contact with the NMMO aqueous solution, resulting in the phenomenon that the outer diameter of the swollen cellulose particles is small and the area of ​​the dry cellulose particles in the middle is large; 2. From t1 seconds to t2 seconds, most of the volume of the cellulose particles is in contact with the NMMO aqueous solution, the area of ​​the entire cellulose particles is larger than that at t1 seconds, and the area of ​​the internal dry cellulose particles is further reduced; 3. From t2 seconds to 60 seconds, the cellulose particles are completely immersed in the NMMO aqueous solution, and the overall area of ​​the cellulose particles is further increased, but there is still a large area of ​​dry cellulose particles in the center. This phenomenon can easily lead to problems such as uneven solid content of cellulose pulp and formation of white core.

[0017] In summary, in the equal-diameter mixing cylinder, the cellulose particles fail to fully contact with the NMMO aqueous solution, which easily leads to insufficient swelling of the cellulose particles, resulting in uneven solid content of the cellulose pulp porridge, formation of white core and other problems during the actual production process; while the variable-diameter mixing cylinder and the spiral blade structure in the present invention enable the cellulose particles to fully contact and stir with the NMMO aqueous solution, thereby improving the swelling degree and efficiency of the cellulose particles. Furthermore, since the cellulose particles are a material that easily absorbs the NMMO aqueous solution, after fully contacting and stirring and absorbing the NMMO aqueous solution, the volume of the cellulose particles will increase, the strength will decrease sharply, and the texture will become soft and easy to break, thereby improving the crushing efficiency of the cellulose particles and the uniformity of the solid content of the cellulose pulp porridge.

[0018] The diameter of the small cylindrical barrel is 900~1000mm, and the ratio of the diameter of the small cylindrical barrel to the large cylindrical barrel is 0.7~0.9:1, which can prevent the problem of rapid outflow of the solution from the material outlet. The semi-apex angle of the truncated cone barrel is 30°~60°, the total length of the mixing barrel is 3500~6000mm, and the length of the large cylindrical barrel is 10~40% of the total length of the mixing barrel.

[0019] In the present invention, by setting a reasonable half-apex angle of the truncated cone-shaped cylinder, the purpose of reducing the mixing dead zone (avoiding the generation of vortices at the truncated cone-shaped cylinder), facilitating the flow of swollen cellulose particles, reducing solution waste and facilitating processing and assembly is achieved. In the present invention, the half-apex angle α of the truncated cone-shaped cylinder is set to 30°~60°, and the reason is: ① When the half-apex angle α of the truncated cone-shaped cylinder is greater than 60°, a mixing dead zone will be formed at the truncated cone-shaped cylinder, causing uneven mixing, thereby affecting the mixing uniformity of cellulose particles and NMMO aqueous solution, and affecting the final product quality. For example, when the half-apex angle α of the truncated cone-shaped cylinder is close to 90°, the mixed material will be detained for a long time at the step where the large cylindrical cylinder and the small cylindrical cylinder meet, and no flow will be generated, forming a mixing dead zone, which seriously affects the mixing uniformity of cellulose particles and NMMO aqueous solution, so it is not advisable to set a step with a larger slope at this place. ② When the semi-apex angle α of the truncated cone is less than 30°, the length of the truncated cone is long, which makes it easy for the NMMO aqueous solution to flow to the cellulose slurry outlet, reducing the contact area between the cellulose particles and the NMMO aqueous solution, which is not conducive to the full swelling of the cellulose particles, thereby affecting the final product quality. In addition, the flow of the NMMO aqueous solution to the outlet will also cause part of the solution to flow directly out of the slurry outlet, resulting in a waste of solution. ③ A semi-apex angle α of 30°~60° is conducive to the transportation of the swollen cellulose particles from the large cylindrical barrel to the small cylindrical barrel, thereby accurately controlling the swelling time of the cellulose particles.

[0020] In the present invention, the diameter of the small cylindrical barrel is 900-1000 mm, and the ratio of the diameter of the small cylindrical barrel to the diameter of the large cylindrical barrel is 0.7-0.9:1. The reasons are as follows: ① If the diameter of the device (the diameter of the small cylindrical barrel) is increased, the following problems will be caused: increasing the diameter of the device will easily lead to low crushing efficiency and uneven mixing around the stirring shaft, affecting the uniformity of material mixing in the mixing device and the final product quality; increasing the diameter of the device will also increase the unit energy consumption. ② If the diameter of the device is reduced, the following problems will be caused: the contact area between the cellulose particles and the NMMO aqueous solution will be reduced, resulting in uneven swelling and uneven mixing, affecting the final product quality; the output of cellulose pulp will be reduced; the unit energy consumption will increase; the fixed investment of the equipment will increase; and the later maintenance cost will increase. ③ If the ratio of the diameter of the small cylinder to the large cylinder is increased, that is, the diameter of the large cylinder is increased alone, the following problems will be caused: a dead zone will be easily formed around the stirring shaft, which will affect the swelling degree and uniformity of the cellulose particles, causing uneven swelling, thus affecting the mixing and crushing efficiency; the mixed material will be retained for a long time at the step where the large cylinder and the small cylinder meet, without flowing, forming a dead zone, affecting the mixing uniformity; causing the material conveying amount to the next area (crushing area) to be too large, thus causing uneven crushing and affecting the crushing efficiency. ④ If the ratio of the diameters of the two is reduced, the following problems will be caused: the liquid storage volume of the bottom of the large cylinder as a small "liquid storage tank" is reduced, reducing the contact area between the cellulose particles and the NMMO aqueous solution, causing uneven swelling of the cellulose particles, thus affecting the final product quality; it is easy for the NMMO aqueous solution that will not be absorbed by the cellulose particles in the future to flow out from the cellulose slurry outlet, causing uneven swelling of the cellulose particles and waste of solution. In summary, the diameter of the small cylindrical tube set in the present invention is 900-1000 mm, and the ratio of the diameter of the small cylindrical tube to the large cylindrical tube is 0.7-0.9:1, which is a more reasonable size range set under the condition of improving the swelling efficiency and comprehensively considering other various influencing factors.

[0021] In the present invention, the total length of the mixing drum is 3500-6000 mm, and the length of the large cylindrical drum is 10-40% of the total length of the mixing drum. The reasons are as follows: ① If the total length of the mixing drum is increased, the following problems are caused: the length of the mixing drum and the agitator is too long, and the mechanical manufacturing and processing are difficult; the unit energy consumption of the device is increased; and the maintenance cost of the device in the later stage is increased. ② If the total length of the mixing drum is reduced, the following problems are caused: the cellulose particles are not fully swollen, thereby affecting the swelling and crushing efficiency; the cellulose particles have low crushing efficiency, uneven solid content of cellulose pulp porridge, and the formation of white core; the cellulose pulp porridge output is reduced; and the unit energy consumption of the device is increased. ③ If the length ratio of the large cylindrical drum is increased, the following problems are caused: since the agitator at the large cylindrical drum is provided with a spiral blade, this type of blade has no crushing effect on the cellulose particles, so increasing the length ratio of the large cylindrical drum will cause problems such as low crushing efficiency, uneven solid content of cellulose pulp porridge, and the formation of white core; since the absorption of NMMO aqueous solution by cellulose particles shows an exponential decay trend, increasing the length ratio of the large cylindrical drum will not significantly increase the swelling degree of cellulose particles. ④ If the length ratio of the large cylindrical barrel is reduced, the following problems will be caused: uneven mixing of cellulose particles and NMMO aqueous solution will affect the swelling degree and uniformity of cellulose particles; insufficient swelling of cellulose particles will cause low crushing efficiency, uneven solid content of cellulose pulp and formation of white core; in addition, practice shows that the swelling time of cellulose particles is more suitable for 1 / 3 of the total mixing and crushing time. In short, the total length of the mixing barrel set by the present invention is 3500~6000mm, and the length of the large cylindrical barrel is 10~40% of the total length of the mixing barrel, which is a more reasonable size range set under the condition of improving swelling, crushing efficiency and comprehensively considering other influencing factors.

[0022] As the preferred technical solution:

[0023] In the horizontal crushing and mixing device for producing cellulose pulp as described above, the vertical center line of the cellulose pulp outlet does not coincide with the vertical center line of the large cylindrical barrel, and the distance does not exceed 200 mm. Such an arrangement is more conducive to the discharge of materials.

[0024] In the horizontal crushing and mixing device for producing cellulose pulp as described above, the agitator rotates in a clockwise direction.

[0025] The crushing and mixing device of the present invention will eventually crush and mix the cellulose particles and the NMMO aqueous solution into a porridge-like mixture, which has a certain fluidity, but the fluidity is poor and it is easy to accumulate; the agitator of the crushing and mixing device of the present invention is set to rotate clockwise. Due to the rotating driving effect of the agitator, the porridge-like mixture in the discharge area will accumulate on one side of the mixing barrel (the left side of the mixing barrel) rather than the middle; in order to facilitate the discharge of the mixed material and reduce the size of the material outlet, the crushing and mixing device of the present invention adopts a structure in which the material outlet is vertically eccentrically arranged.

[0026] Principle of the invention:

[0027] The invention discloses a horizontal crushing and mixing device for producing cellulose porridge, wherein the cylinder of the mixing cylinder is a variable diameter structure, and the cylinder is connected by a cone transition in the middle, that is, the cylinder diameter of the left section (the area where the cellulose particle inlet is located) is larger than the diameter of the cylinder of the right section. When the NMMO aqueous solution is injected from the NMMO aqueous solution inlet, the bottom of the large diameter D can be used as a small "liquid storage tank" to store a small amount of the injected NMMO aqueous solution for a short time, and the variable diameter mixing cylinder and the spiral blades cooperate with each other to form a relatively closed stirring area to stir the cellulose particles and the NMMO aqueous solution, so that the cellulose particles fully absorb the NMMO aqueous solution and fully swell; in addition, under the condition of the same liquid level height in the mixing cylinder, the large diameter cylinder increases the contact area between the cellulose particles and the NMMO aqueous solution, thereby improving the swelling efficiency of the cellulose particles. Without the "liquid storage tank" structure and the closed stirring area formed, when the NMMO aqueous solution is injected from the NMMO aqueous solution inlet, it is impossible for the cellulose particles to completely absorb the NMMO aqueous solution instantly, and the NMMO aqueous solution has strong fluidity, thus causing some cellulose particles to not swell fully and the NMMO aqueous solution to quickly flow out of the material outlet and cause solution waste.

[0028] Beneficial effects:

[0029] (1) The mixing cylinder of the horizontal variable diameter crushing and mixing device of the present invention has a variable diameter structure. The combination of the large cylindrical cylinder and the truncated cone cylinder allows the bottom of the mixing cylinder to be used as a small "liquid storage tank", thereby increasing the contact area between the cellulose particles and the NMMO aqueous solution and making the two mixed more uniformly. The cellulose particles can also fully absorb the NMMO aqueous solution and swell fully. In addition, the variable diameter structure can also prevent the solution from flowing out of the material outlet quickly, thereby improving the utilization rate of the solution and reducing the waste of the solution.

[0030] (2) In a horizontal variable diameter crushing and mixing device of the present invention, the material outlet is vertically eccentrically arranged, that is, the vertical center line of the material outlet deviates from one side of the vertical center line of the mixing barrel. The eccentric arrangement can prevent material accumulation and improve material discharge efficiency.

[0031] (3) The variable diameter mixing cylinder and the spiral blades of the present invention form a spiral pump structure, which can quantitatively push the cellulose particles absorbed by the NMMO aqueous solution to the next area, thereby controlling the crushing and mixing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a three-dimensional structural diagram of a mixing cylinder in a horizontal crushing and mixing device of the present invention;

[0033] Figure 2 It is a front view of a mixing drum in a horizontal crushing and mixing device of the present invention;

[0034] Figure 3 It is a side cross-sectional view of the material outlet of the mixing cylinder in the horizontal crushing and mixing device of the present invention;

[0035] Figure 4 It is a front view of the spiral pump structure formed by the spiral blade and the mixing cylinder in the horizontal crushing and mixing device of the present invention; in the figure, P is the pitch of the spiral blade, and δ is the gap between the top of the spiral blade and the inner wall of the mixing cylinder;

[0036] Figure 5 Schematic diagram of the swelling process of cellulose particles in NMMO aqueous solution of the present invention;

[0037] Figure 6 It is a schematic diagram of the swelling process of cellulose particles in NMMO aqueous solution in the prior art;

[0038] Figure 7 It is a schematic diagram of the overall structure of the horizontal crushing and mixing device of the present invention;

[0039] Among them, 1-cellulose particle inlet, 2-mixing cylinder, 3-cellulose porridge outlet, 4-NMMO aqueous solution inlet, 5-segmented propeller blade support rod, 6-segmented propeller blade, 8-spiral blade, 9-crushing blade, 11-discharge rod, 12-stirring shaft, 13-crushing blade support rod. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0041] A horizontal crushing and mixing device for producing cellulose pulp porridge, such as Figure 1 , 7 As shown, it includes a mixing barrel 2 and an agitator installed in the mixing barrel 2 in a coaxial manner;

[0042] The cylinder body of the mixing cylinder 2 is a variable diameter structure, which is composed of a large cylindrical cylinder, a truncated cone cylinder and a small cylindrical cylinder which are placed horizontally and coaxially in sequence;

[0043] like Figure 2 As shown, the diameter d of the small cylindrical barrel is 900-1000 mm, the ratio of the diameter (d) of the small cylindrical barrel to the diameter (D) of the large cylindrical barrel is 0.7-0.9:1, the semi-apex angle α of the truncated cone barrel is 30°-60°, the total length L of the mixing barrel 2 is 3500-6000 mm, and the length A of the large cylindrical barrel is 10-40% of the total length of the mixing barrel 2;

[0044] The diameter of the large end of the truncated cone-shaped cylinder is equal to the diameter of the large cylindrical cylinder, and the diameter of the small end of the truncated cone-shaped cylinder is equal to the diameter of the small cylindrical cylinder;

[0045] A cellulose particle inlet 1 is provided on the large cylindrical cylinder at a position away from the truncated cone-shaped cylinder, an NMMO aqueous solution inlet 4 is provided on the large cylindrical cylinder at a position close to the truncated cone-shaped cylinder, and a cellulose slurry outlet 3 is provided on the small cylindrical cylinder at a position away from the truncated cone-shaped cylinder;

[0046] like Figure 3 As shown, the vertical center line of the cellulose pulp porridge outlet 3 does not coincide with the vertical center line of the large cylindrical barrel, and the distance B between the vertical center line of the cellulose pulp porridge outlet 3 and the vertical center line of the large cylindrical barrel does not exceed 200 mm;

[0047] like Figure 7 As shown, the stirrer includes a stirring shaft 12, on which a segmented propeller, a spiral blade 8, 20 groups of crushing paddles and 2 groups of discharge rods 11 are sequentially mounted from left to right;

[0048] The agitator rotates in a clockwise direction;

[0049] The segmented propeller comprises six segmented propeller blade support rods 5 and six segmented propeller blades 6;

[0050] The tops of the six segmented propeller blade support rods 5 are fixedly connected to the bottoms of the six segmented propeller blades 6, respectively, and the bottoms of the six segmented propeller blade support rods 5 are fixed to the stirring shaft 12 of the stirrer in a spiral arrangement;

[0051] The pitch of the segmented propeller is 100mm~300mm, and the distance between the blades is set at 40mm~180mm;

[0052] like Figure 4 As shown, the bottom of the spiral blade 8 is directly fixed to the stirring shaft 12 of the stirrer;

[0053] The pitch P of the spiral blade is set to 100 mm to 300 mm, and the gap δ between the top of the spiral blade and the inner wall of the mixing cylinder is set to 1 to 15 mm;

[0054] The mixing cylinder and the spiral blades cooperate with each other to form a relatively closed stirring area to stir the cellulose particles and the NMMO aqueous solution, so that the cellulose particles fully absorb the NMMO aqueous solution and fully swell;

[0055] The crushing paddle comprises a crushing blade 9 and a crushing blade support rod 13;

[0056] The bottom of the crushing blade 9 is fixedly connected to the top of the crushing blade support rod 13, and the bottom of the crushing blade support rod 13 is fixed to the stirring shaft 12 of the stirrer;

[0057] The installation angle of the crushing blade 9 (i.e., the angle between the plane where the crushing blade is located and the axis of the stirring shaft, with the opening of the angle facing the material outlet direction) is set at 30°~55°, and the gap between the top of the crushing blade 9 and the inner wall of the mixing cylinder is set to 5~15mm;

[0058] Each group of crushing blades includes at least three crushing blades 9 and crushing blade support rods 13 that are evenly arranged and deflected around the stirring shaft 12, and two adjacent groups of crushing blades are staggered in the circumferential direction;

[0059] Among the 20 groups of crushing blades, two groups (or several groups) of crushing blades 9 are fixed on the stirring shaft 12 in a radially vertical manner through the bottom of the crushing blade support rod 13;

[0060] Each group of crushing blades 9 fixed in a radial vertical manner comprises at least three crushing blades 9 evenly arranged around the stirring shaft 12 and a crushing blade support rod 13;

[0061] The bottom of the discharge rod 11 is fixedly connected to the stirring shaft 12 of the stirrer;

[0062] Each group of discharge rods includes two discharge rods 11 evenly arranged around the stirring shaft 12, and two adjacent groups of discharge rods are staggered in the circumferential direction.

[0063] In order to verify the mixing effect of the above-mentioned device on cellulose particles and NMMO aqueous solution, the above-mentioned horizontal crushing and mixing device is now used to mix cellulose particles and NMMO aqueous solution, wherein the diameter d of the small cylindrical barrel in the horizontal crushing and mixing device is 950 mm, the ratio of the diameter (d) of the small cylindrical barrel to the diameter (D) of the large cylindrical barrel is 0.8:1, the semi-apex angle α of the truncated cone barrel is 45°, the total length L of the mixing barrel is 5000 mm, the length A of the large cylindrical barrel is 27% of the total length of the mixing barrel, the vertical center line of the cellulose pulp outlet and the vertical center line of the large cylindrical barrel are 150 mm, the pitch of the segmented propeller is 300 mm, the spacing between the blades is set at 40 mm, the pitch P of the spiral blade is set to 300 mm, the gap δ between the top of the spiral blade and the inner wall of the mixing barrel is set to 10 mm, the installation angle of the crushing blade 9 is 45°, and the gap between the top of the crushing blade 9 and the inner wall of the mixing barrel is 10 mm;

[0064] The outer diameter of the stirring shaft is 305mm, the outer diameter of the crushing blade support rod is 40mm, the thickness of the crushing blade is 16mm, each group of crushing blades includes three crushing blades that are evenly arranged and deflected and fixed around the stirring shaft, and a total of 20 groups of crushing blades are arranged along the axial direction, and the axial spacing between two adjacent groups of crushing blades is 160mm; among the 20 groups of crushing blades, two groups of crushing blades are fixed to the stirring shaft in a radially vertical manner through the bottom of the crushing blade support rod; each group of crushing blades fixed in a radially vertical manner includes three crushing blades evenly arranged around the stirring shaft and a crushing blade support rod;

[0065] First, the outer wall of the mixing cylinder with a variable diameter structure is heated to 75°C in a water bath, and the speed of the agitator is set to 122 rpm. Then, cellulose particles and NMMO aqueous solution with a mass ratio of 11.4:88.6 (the mass ratio of NMMO to water is 67.9:20.7) are respectively introduced into the large cylindrical cylinder through the cellulose particle inlet and the NMMO aqueous solution inlet. The cellulose particles move toward the position of the spiral blades under the push of the segmented propeller blades, and at the same time, they are initially swollen with the NMMO aqueous solution in the "liquid storage tank" structure formed at the bottom of the large cylindrical cylinder. Then, the initially swollen cellulose particles are further axially and radially mixed with the NMMO aqueous solution through the spiral blades. The mixing and stirring enables the cellulose particles to fully swell. The fully swollen cellulose particles and part of the NMMO aqueous solution will be transported to the crushing blade position under the push of the spiral blade, and gradually broken into cellulose particles with smaller diameters under the continuous striking and shearing action of the crushing blade. Under the stirring of the crushing blade, they are evenly mixed with the NMMO aqueous solution to form cellulose slurry. Since the crushing blade is installed at a certain angle to the axis of the stirring shaft, the cellulose slurry can be pushed to the position of the discharge rod while being evenly mixed. When the cellulose slurry is transported to the position of the discharge rod, the rotating movement of the discharge rod will discharge the cellulose slurry from the cellulose slurry outlet to obtain cellulose slurry.

[0066] The mixed cellulose pulp porridge was taken out from the cellulose pulp porridge prepared above by a sampler as a sample, 2.5 g of the sample was weighed and put into a 250 ml beaker, and 200 ml of boiling distilled water was added and stirred evenly, and then placed on a heated magnetic stirrer (C-MAG HS 10 model) and boiled for 10 minutes, and then filtered with a G2 sand core crucible, and then repeatedly rinsed with 400 ml of hot distilled water at a temperature of 75° C. until there was no NMMO content, and then placed in a drying oven (PH-070A model) at 200° C. for 15 minutes. After taking out, cool for 15 minutes and weigh the weight;

[0067] Repeat the above steps 5 times, calculate the average weight (i.e. the cellulose content), and finally compare it with the theoretical weight (theoretical weight is 11.4%). It is found that the difference between the two weights is very small, indicating that the solid content of the cellulose pulp porridge is uniform, that is, the cellulose pulp porridge is of high quality.

Claims

1. A horizontal crushing and mixing device for producing cellulose porridge, comprising a mixing drum and an agitator coaxially mounted in the mixing drum, characterized in that: The body of the mixing cylinder is a variable diameter structure; The mixing cylinder is composed of a large cylindrical cylinder, a truncated cone cylinder and a small cylindrical cylinder which are placed horizontally and coaxially and connected in sequence. The diameter of the large end of the truncated cone cylinder is equal to the diameter of the large cylindrical cylinder, and the diameter of the small end of the truncated cone cylinder is equal to the diameter of the small cylindrical cylinder. A cellulose particle inlet is provided on the large cylindrical cylinder at a position away from the truncated cone-shaped cylinder, an NMMO aqueous solution inlet is provided on the large cylindrical cylinder at a position close to the truncated cone-shaped cylinder, and a cellulose slurry outlet is provided on the small cylindrical cylinder at a position away from the truncated cone-shaped cylinder; The stirrer comprises a stirring shaft and a stirring blade fixed on the stirring shaft, and the stirring blade is a spiral blade; The mixing cylinder and the spiral blades cooperate with each other to form a relatively closed stirring area to stir the cellulose particles and the NMMO aqueous solution, so that the cellulose particles fully absorb the NMMO aqueous solution and fully swell; The diameter of the small cylindrical barrel is 900~1000mm, the ratio of the diameter of the small cylindrical barrel to the large cylindrical barrel is 0.7~0.9:1, the semi-apex angle of the truncated cone barrel is 30°~60°, the total length of the mixing barrel is 3500~6000mm, and the length of the large cylindrical barrel is 10~40% of the total length of the mixing barrel.

2. A horizontal crushing and mixing device for producing cellulose pulp according to claim 1, characterized in that: The vertical center line of the cellulose pulp outlet does not coincide with the vertical center line of the large cylindrical barrel, and the distance between them does not exceed 200mm.

3. A horizontal crushing and mixing device for producing cellulose pulp according to claim 1, characterized in that: The agitator rotates in clockwise direction.

Images