System for preparing Lyocell fiber spinning dope by modifying wood pulp
By combining modified processing equipment, the quality problem of pulp used in the production of lyocell fiber in China has been solved, achieving efficient removal of impurities and adjustment of polymerization degree, and producing spinning dope suitable for lyocell fiber.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- YIBIN GRACE GROUP CO LTD
- Filing Date
- 2025-05-29
- Publication Date
- 2026-05-26
AI Technical Summary
The pulp used for lyocell fiber production in China mainly relies on imports. Existing technology is unable to effectively address the quality issues of domestic pulp, resulting in cellulose and metal ion content that is unsuitable for lyocell fiber production.
By combining equipment such as an enzymatic purification kettle, a water washing kettle, a bleaching and impurity removal kettle, and a thin-film evaporator, enzyme treatment, alkaline leaching purification, water washing, oxidative bleaching, and dissolution treatment are carried out to remove ash and metal ions from the pulp, adjust the degree of polymerization, and obtain a dosing suitable for spinning lyocell fibers.
It achieves efficient removal of impurities from pulp, increases cellulose content and degree of polymerization, reduces metal ion content, ensures good dissolution of spinning solution in NMMO solution, and produces high-quality lyocell fibers.
Smart Images
Figure CN224280567U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lyocell fiber spinning dope preparation technology, specifically relating to a system for preparing lyocell fiber spinning dope by modifying wood pulp. Background Technology
[0002] Lyocell fiber is a novel regenerated cellulose fiber produced by dissolving pulp raw materials in N-methylmorpholine-N-oxide (NMMO) as a solvent and then spinning it using a dry-jet wet-spinning process. Compared to viscose fiber, lyocell fiber is not only soft, silky, breathable, and lustrous, but also possesses superior mechanical properties and moisture absorption. Moreover, the entire production process of lyocell fiber involves no chemical reactions and produces virtually no toxic or harmful substances. Therefore, lyocell fiber is hailed as the "green fiber of the 21st century."
[0003] Currently, with the continuous maturation of production technology and the localization of production equipment, the domestic production capacity of lyocell fiber has been further released. However, due to the special nature of the production process, the quality requirements for pulp used in lyocell fiber production are higher than those for pulp used in ordinary viscose fiber production. Very few pulp mills in China are capable of producing dedicated lyocell fiber pulp; most primarily produce paper pulp and dissolving pulp for ordinary viscose fiber. Paper pulp has a low formaldehyde content, but a high cellulose content, as well as higher levels of ash, metal ions, and polymerization, making it unsuitable for lyocell fiber production. Dissolving pulp for ordinary viscose fiber has a lower degree of polymerization, leading to reduced fiber strength, and also has a higher metal ion content, making it unsuitable for lyocell fiber production. Therefore, China currently relies heavily on imports for pulp used in lyocell fiber production. Utility Model Content
[0004] The purpose of this invention is to solve the problems of the existing technology and provide a system for preparing lyocell fiber spinning dope by modifying wood pulp. Demineralized water is added to the enzymatic hydrolysis purification vessel through a first inlet pipe. Cellulose wood pulp raw material (sheet pulp) is then added to the enzymatic hydrolysis purification vessel through the raw material inlet. Cellulase solution is then added through the first inlet pipe, and enzymatic treatment and depolymerization are performed in the enzymatic hydrolysis purification vessel. After the enzymatic treatment and depolymerization are completed, alkali solution is added through the first inlet, and alkali leaching purification is performed in the enzymatic hydrolysis purification vessel. After alkali leaching purification, the solution is fed into the first washing vessel through a first connecting pipe, a first transfer pump, and a first press. Demineralized water is added through a second inlet pipe to remove residual alkali on the pulp in the first washing vessel, washing the pulp to neutral. After the first washing, the solution is fed into the bleaching and impurity removal vessel through a second connecting pipe, a second transfer pump, and a second press, and then further processed through a third... Demineralized water, acid, and a complexing agent are added through the inlet pipe. Ash and metal ions are removed from the pulp raw material in the bleaching and impurity removal kettle, and the pulp raw material undergoes oxidative bleaching and the degree of polymerization is adjusted. After bleaching and impurity removal, the pulp is fed into the second washing kettle through the third connecting pipe, the third transfer pump, and the third press. Demineralized water is added through the fourth inlet pipe. Residual acid, complexing agent, and metal ions on the pulp are removed in the second washing kettle, and the pulp is washed to neutral. After the second washing, the pulp is fed into the pulper through the fourth connecting pipe, the fourth transfer pump, the fourth press, and the pulverizer. A high-concentration NMMO aqueous solution is added through the pulping inlet pipe. Under the action of the pulper, the pulp swells fully, yielding a cellulose suspension. The cellulose suspension is fed into the thin-film evaporator through the fifth connecting pipe and the screw pump. The cellulose suspension dissolves in the thin-film evaporator to obtain the lyocell fiber spinning solution.
[0005] This utility model is achieved through the following technical solution:
[0006] A system for preparing lyocell fiber spinning dope by modifying wood pulp includes an enzymatic hydrolysis purification vessel, a first washing vessel, a bleaching and impurity removal vessel, a second washing vessel, a pulverizer, a pulper, and a thin-film evaporator. The lower end of the enzymatic hydrolysis purification vessel is connected to a first connecting pipe, on which a first conveying pump and a first press are installed. The discharge end of the first press's outlet trough is located above the inlet of the first washing vessel. The lower end of the first washing vessel is connected to a second connecting pipe, on which a second conveying pump and a second press are installed. The discharge end of the second press's outlet trough is located above the inlet of the bleaching and impurity removal vessel. The lower end of the reactor is connected to a third connecting pipe, on which a third conveying pump and a third press are installed. The discharge end of the discharge chute of the third press is located above the inlet of the second washing reactor. The lower end of the second washing reactor is connected to a fourth connecting pipe, on which a fourth conveying pump and a fourth press are installed. The discharge end of the fourth press is connected to the inlet of the crusher. The discharge outlet of the crusher is connected to the inlet of the pulper. The discharge outlet of the pulper is connected to a fifth connecting pipe, on which a screw conveying pump is installed. The discharge outlet of the screw conveying pump is connected to the inlet of the thin-film evaporator.
[0007] Preferably, the enzymatic hydrolysis purification vessel includes a first inner cylinder and a first outer cylinder. The first inner cylinder is fixedly disposed inside the first outer cylinder. A raw material inlet, a first liquid inlet pipe, and a first stirring motor are disposed above the first outer cylinder. The first stirring motor is connected to a first stirring shaft. The first stirring shaft passes through the first outer cylinder and enters the interior of the first outer cylinder. The first stirring shaft passes through both ends of the first inner cylinder. The lower end of the first stirring shaft is connected to the lower end of the inner wall of the first outer cylinder through a bearing seat. Multiple toothed stirring blades are disposed on the first stirring shaft inside the first inner cylinder. Multiple stationary toothed blades are also fixedly disposed inside the first inner cylinder. A first discharge port is disposed at the lower end of the inner wall of the first outer cylinder. The first discharge port is connected to a first connecting pipe.
[0008] Preferably, a first guide impeller is also provided on the first stirring shaft at the lower end of the first inner cylinder.
[0009] Preferably, the first washing kettle, the bleaching and impurity removal kettle, and the second washing kettle include a second inner cylinder and a second outer cylinder. The second inner cylinder is fixedly disposed inside the second outer cylinder. A second feed inlet, a second liquid inlet pipe, and a second stirring motor are disposed above the second outer cylinder. The second stirring motor is connected to a second stirring shaft. The second stirring shaft passes through the second outer cylinder and enters the interior of the second outer cylinder. The second stirring shaft passes through both ends of the second inner cylinder. The lower end of the second stirring shaft is connected to the lower end of the inner wall of the second outer cylinder through a bearing seat. Multiple impellers are disposed on the second stirring shaft inside the second inner cylinder. A second discharge port is also disposed at the lower end of the inner wall of the second outer cylinder. The second discharge port is connected to a second connecting pipe, a third connecting pipe, or a fourth connecting pipe.
[0010] Preferably, a second guide impeller is also provided on the second stirring shaft at the lower end of the second inner cylinder.
[0011] Preferably, the outer sides of the enzymatic hydrolysis purification vessel, the first washing vessel, the bleaching and impurity removal vessel, the second washing vessel, and the pulper are all provided with a heat insulation layer.
[0012] Preferably, a pre-crusher is also provided between the fourth press and the crusher.
[0013] Preferably, the pulper includes a pulper outer cylinder, with a pulper inlet and a pulp inlet pipe at the upper end of the outer cylinder, a pulping shaft at the lower end of the outer cylinder, the pulping shaft passing through the outer cylinder and entering the pulper interior, a conical pulping body being provided on the pulping shaft inside the pulper, and a pulper outlet at the lower end of the outer cylinder.
[0014] Preferably, a first pulley is provided at the end of the pulping shaft away from the outer cylinder of the pulper, and the first pulley is connected to a second pulley on the pulping motor via a transmission belt.
[0015] Preferably, valves are provided on the first connecting pipe, the second connecting pipe, the third connecting pipe and the fourth connecting pipe.
[0016] Compared with the prior art, this utility model has the following advantages and beneficial effects:
[0017] I. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model includes: Demineralized water is added to the enzymatic hydrolysis purification kettle through a first inlet pipe; subsequently, cellulose wood pulp raw material (sheet pulp) is added to the enzymatic hydrolysis purification kettle through the raw material inlet; then, cellulase solution is added through the first inlet pipe, and enzymatic treatment and depolymerization are performed in the enzymatic hydrolysis purification kettle; after the enzymatic treatment and depolymerization are completed, alkali solution is added through the first inlet, and alkali leaching purification is performed in the enzymatic hydrolysis purification kettle; after the alkali leaching purification is completed, it is fed into the first washing kettle through a first connecting pipe, a first transfer pump, and a first press; demineralized water is added through a second inlet pipe to remove residual alkali on the pulp in the first washing kettle, washing the pulp to neutral; after the first washing is completed, it is fed into the bleaching and impurity removal kettle through a second connecting pipe, a second transfer pump, and a second press; and demineralized water is added through a third inlet pipe. Brine, acid, and complexing agents are used in a bleaching and impurity removal reactor to remove ash and metal ions from the pulp raw material, and to oxidize and bleach the pulp raw material and adjust the degree of polymerization. After bleaching and impurity removal, the pulp is fed into a second washing reactor through a third connecting pipe, a third transfer pump, and a third press. Demineralized water is added through a fourth inlet pipe to remove residual acid, complexing agents, and metal ions from the pulp in the second washing reactor, washing the pulp to neutral. After the second washing, the pulp is fed into a pulper through a fourth connecting pipe, a fourth transfer pump, a fourth press, and a pulverizer. A high-concentration NMMO aqueous solution is added through the pulper inlet pipe, and the pulp is fully swollen under the action of the pulper to obtain a cellulose suspension. The cellulose suspension is fed into a thin-film evaporator through a fifth connecting pipe and a screw pump, where it dissolves to obtain lyocell fiber spinning solution.
[0018] II. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model has the following advantages: each device in this system can achieve continuous feeding and discharging, with low material loss and low overall energy consumption. Furthermore, the modified pulp has a high methyl cellulose content, a degree of polymerization that meets the lyocell-specific pulp index, and a low metal ion content. It also exhibits good swelling and dissolution effects in NMMO solution, and the final spinning dope has good spinnability and can be used to produce lyocell fibers.
[0019] III. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model includes a first inner tank for ensuring that the pulp is crushed in the solvent and that the pulp porridge is tumbled in the first inner tank; geared stirring blades for crushing the pulp in the solvent during stirring and stirring the pulp porridge to ensure that the cellulose is evenly impregnated in the solvent; stationary geared blades for cooperating with the geared stirring blades to crush the pulp in the solvent during stirring; and a first guide impeller for assisting the pulp porridge to tumble from the first inner tank to the first outer tank.
[0020] IV. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model includes a second inner tank for ensuring that the pulp is crushed in the solvent and that the pulp porridge is tumbled in the second inner tank, an impeller 15 for stirring the pulp porridge to make the cellulose evenly impregnated in the solvent, and a second guide impeller for assisting the pulp porridge to tumble from the second inner tank to the second outer tank.
[0021] V. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model has a heat insulation layer to provide stable temperature conditions for the device.
[0022] VI. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model includes a pre-crusher for coarsely crushing the pressed pulp and a crusher for finely crushing the pressed pulp. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the structure of this utility model;
[0024] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of this utility model;
[0025] Figure 3 This is a schematic diagram of the enzymatic hydrolysis purification vessel in this utility model;
[0026] Figure 4 This is a schematic diagram of the structure of the first washing tank, bleaching and impurity removal tank, or the second washing tank in this utility model;
[0027] Figure 5 This is a schematic diagram of the structure of the first, second, third, or fourth press in this utility model;
[0028] Figure 6 This is a schematic diagram of the pulper in this utility model;
[0029] The components include: 1. Enzymatic hydrolysis purification kettle; 101. First inner cylinder; 102. First outer cylinder; 103. Raw material inlet; 104. First liquid inlet pipe; 105. First stirring motor; 106. First stirring shaft; 107. Toothed stirring blade; 108. Stationary toothed blade; 109. First discharge port; 110. First guide impeller; 2. First washing kettle; 201. Second inner cylinder; 202. Second outer cylinder; 203. Second feed port; 204. Second liquid inlet pipe; 205. Second stirring motor; 206. Second stirring shaft; 207. Impeller; 208. Second discharge port; 209. Second guide impeller; 3. Bleaching and impurity removal kettle; 4. Second washing kettle; 5. Crusher; 6. Pulper; 601. Pulper 602. Outer cylinder; 603. Pulper feed inlet; 604. Pulper liquid inlet pipe; 605. Pulper shaft; 606. Conical pulp body; 607. Pulper discharge outlet; 608. First pulley; 609. Drive belt; 610. Pulper motor; 611. Second pulley; 7. Thin-film evaporator; 8. First connecting pipe; 9. First conveying pump; 10. First press; 11. Second connecting pipe; 12. Second conveying pump; 13. Second press; 14. Third connecting pipe; 15. Third conveying pump; 16. Third press; 17. Fourth connecting pipe; 18. Fourth conveying pump; 19. Fourth press; 20. Fifth connecting pipe; 21. Screw conveying pump; 22. Insulation layer; 23. Pre-crusher; 24. Valve. Detailed Implementation
[0030] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.
[0031] Example 1
[0032] like Figure 1As shown, this embodiment provides a system for preparing lyocell fiber spinning dope by modifying wood pulp, including an enzymatic purification kettle 1, a first washing kettle 2, a bleaching and impurity removal kettle 3, a second washing kettle 4, a pulverizer 5, a pulper 6, and a thin-film evaporator 7. The lower end of the enzymatic purification kettle 1 is connected to a first connecting pipe 8, on which a first conveying pump 9 and a first press 10 are installed. The discharge end of the discharge trough of the first press 10 is located above the inlet of the first washing kettle 2. The lower end of the first washing kettle 2 is connected to a second connecting pipe 11, on which a second conveying pump 12 and a second press 13 are installed. The discharge end of the discharge trough of the second press 13 is located above the inlet of the bleaching and impurity removal kettle 3. The lower end of the mixing vessel 3 is connected to the third connecting pipe 14. A third conveying pump 15 and a third press 16 are installed on the third connecting pipe 14. The discharge end of the discharge chute of the third press 16 is located above the inlet of the second washing vessel 4. The lower end of the second washing vessel 4 is connected to the fourth connecting pipe 17. A fourth conveying pump 18 and a fourth press 19 are installed on the fourth connecting pipe 17. The discharge end of the fourth press 19 is connected to the inlet of the crusher 5. The discharge outlet of the crusher 5 is connected to the inlet of the pulper 6. The discharge outlet of the pulper 6 is connected to the fifth connecting pipe 20. A screw conveying pump 21 is installed on the fifth connecting pipe 20. The discharge outlet of the screw conveying pump 21 is connected to the inlet of the thin-film evaporator 7. The thin-film evaporator 7 is a scraped-plate thin-film evaporator.
[0033] Example 2
[0034] like Figures 2-6As shown, this embodiment provides a system for preparing lyocell fiber spinning dope by modifying wood pulp, including an enzymatic purification kettle 1, a first washing kettle 2, a bleaching and impurity removal kettle 3, a second washing kettle 4, a pulverizer 5, a pulper 6, and a thin-film evaporator 7. The lower end of the enzymatic purification kettle 1 is connected to a first connecting pipe 8, on which a first conveying pump 9 and a first press 10 are installed. The discharge end of the discharge trough of the first press 10 is located above the inlet of the first washing kettle 2. The lower end of the first washing kettle 2 is connected to a second connecting pipe 11, on which a second conveying pump 12 and a second press 13 are installed. The discharge end of the discharge trough of the second press 13 is located above the inlet of the bleaching and impurity removal kettle 3. The lower end of the mixing vessel 3 is connected to the third connecting pipe 14. A third conveying pump 15 and a third press 16 are installed on the third connecting pipe 14. The discharge end of the discharge chute of the third press 16 is located above the inlet of the second washing vessel 4. The lower end of the second washing vessel 4 is connected to the fourth connecting pipe 17. A fourth conveying pump 18 and a fourth press 19 are installed on the fourth connecting pipe 17. The discharge end of the fourth press 19 is connected to the inlet of the crusher 5. The discharge outlet of the crusher 5 is connected to the inlet of the pulper 6. The discharge outlet of the pulper 6 is connected to the fifth connecting pipe 20. A screw conveying pump 21 is installed on the fifth connecting pipe 20. The discharge outlet of the screw conveying pump 21 is connected to the inlet of the thin-film evaporator 7. The thin-film evaporator 7 is a scraped-plate thin-film evaporator.
[0035] The enzymatic hydrolysis purification vessel 1 includes a first inner cylinder 101 and a first outer cylinder 102. The first inner cylinder 101 is fixedly disposed inside the first outer cylinder 102. A raw material inlet 103, a first liquid inlet pipe 104, and a first stirring motor 105 are disposed above the first outer cylinder 102. The first stirring motor 105 is connected to a first stirring shaft 106. The first stirring shaft 106 passes through the first outer cylinder 102 and enters the interior of the first outer cylinder 102. The first stirring shaft 106 passes through the upper and lower ends of the first inner cylinder 101. The lower end of the first stirring shaft 106 is connected to the lower end of the inner wall of the first outer cylinder 102 through a bearing seat. A plurality of toothed stirring blades 107 are disposed on the first stirring shaft 106 inside the first inner cylinder 101. A plurality of stationary toothed blades 108 are also fixedly disposed inside the first inner cylinder 101. A first discharge port 109 is disposed at the lower end of the inner wall of the first outer cylinder 102. The first discharge port 109 is connected to a first connecting pipe 8.
[0036] The first inner cylinder 101 is further provided with a first guide impeller 110 on the first stirring shaft 106 at the lower end of the first inner cylinder 101.
[0037] The first washing tank 2, the bleaching and impurity removal tank 3, and the second washing tank 4 each include a second inner cylinder 201 and a second outer cylinder 202. The second inner cylinder 201 is fixedly installed inside the second outer cylinder 202. A second feed inlet 203, a second liquid inlet pipe 204, and a second stirring motor 205 are provided above the second outer cylinder 202. The second stirring motor 205 is connected to a second stirring shaft 206. The second stirring shaft 206 passes through the second outer cylinder 202 and enters the interior of the second outer cylinder 202. The second stirring shaft 206 passes through the upper and lower ends of the second inner cylinder 201. The lower end of the second stirring shaft 206 is connected to the lower end of the inner wall of the second outer cylinder 202 through a bearing seat. Multiple impellers 207 are provided on the second stirring shaft 206 inside the second inner cylinder 201. A second discharge port 208 is also provided at the lower end of the inner wall of the second outer cylinder 202. The second discharge port 208 is connected to a second connecting pipe 11, a third connecting pipe 14, or a fourth connecting pipe 17.
[0038] A second guide impeller 209 is also provided on the second stirring shaft 206 at the lower end of the second inner cylinder 201.
[0039] The outer sides of the enzymatic hydrolysis purification vessel 1, the first washing vessel 2, the bleaching and impurity removal vessel 3, the second washing vessel 4, and the pulper 4 are all provided with a heat insulation layer 22.
[0040] A pre-crusher 23 is also provided between the fourth press 19 and the crusher 5.
[0041] The pulper 6 includes an outer cylinder 601, with a feed inlet 602 and a pulp inlet pipe 603 at the upper end of the outer cylinder 601, and a pulping shaft 604 at the lower end of the outer cylinder 601. The pulping shaft 604 passes through the outer cylinder 601 and enters the interior of the pulper 6. A conical pulping body 605 is provided on the pulping shaft 604 inside the pulper 6, and a discharge outlet 606 is provided at the lower end of the outer cylinder 601.
[0042] The pulping shaft 604 is provided with a first pulley 607 at the end away from the outer cylinder 601 of the pulper. The first pulley 607 is connected to the second pulley 610 on the pulping motor 609 through a transmission belt 608.
[0043] Valves 24 are provided on the first connecting pipe 8, the second connecting pipe 11, the third connecting pipe 14 and the fourth connecting pipe 17.
[0044] Among them, the first stirring motor 105, the second stirring motor 205, the pulverizer 5, the pulping motor 609, the thin film evaporator 7, the first conveying pump 9, the first press 10, the second conveying pump 12, the second press 13, the third conveying pump 15, the third press 16, the fourth conveying pump 18, the fourth press 19, the screw conveying pump 21, the pre-pulverizer 23, and the valve 24 are all existing technologies and will not be described in detail here.
[0045] Compared with the prior art, this utility model has the following advantages and beneficial effects:
[0046] I. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model includes: Demineralized water is added to the enzymatic hydrolysis and purification vessel 1 through the first inlet pipe 104; subsequently, cellulose wood pulp raw material (sheet pulp) is added to the enzymatic hydrolysis and purification vessel 1 through the raw material inlet 103; cellulase solution is then added through the first inlet pipe 104; enzymatic treatment and depolymerization are performed in the enzymatic hydrolysis and purification vessel 1; after the enzymatic treatment and depolymerization are completed, alkali solution is added through the first inlet; alkali leaching and purification are performed in the enzymatic hydrolysis and purification vessel 1; after the alkali leaching and purification are completed, the solution is fed into the first washing vessel 2 through the first connecting pipe 8, the first transfer pump 9, and the first press 10; demineralized water is added through the second inlet pipe 204; residual alkali on the pulp is removed in the first washing vessel 2, and the pulp is washed to neutral; after the first washing is completed, the solution is fed into the bleaching and impurity removal vessel 3 through the second connecting pipe 11, the second transfer pump 12, and the second press 13; and then demineralized water is added through the third inlet pipe. Demineralized water, acid, and complexing agents are added to the bleaching and impurity removal vessel 3 to remove ash and metal ions from the pulp raw material, and to oxidize and bleach the pulp raw material and adjust the degree of polymerization of the pulp. After the bleaching and impurity removal treatment is completed, the pulp is introduced into the second washing vessel 4 through the third connecting pipe 14, the third transfer pump 15, and the third press 16. Demineralized water is added through the fourth inlet pipe. The acid, complexing agent, and metal ions remaining on the pulp are removed in the second washing vessel 4, and the pulp is washed to neutral. After the second washing is completed, the pulp is introduced into the pulper 6 through the fourth connecting pipe 17, the fourth transfer pump 18, the fourth press 19, and the pulverizer 5. A high-concentration NMMO aqueous solution is added through the pulper inlet pipe 603. Under the action of the pulper 6, the pulp is fully swollen to obtain a cellulose suspension. The cellulose suspension is added into the thin film evaporator 7 through the fifth connecting pipe 20 and the screw pump 21. The cellulose suspension is dissolved in the thin film evaporator 7 to obtain the lyocell fiber spinning solution.
[0047] II. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model has the following advantages: each device in this system can achieve continuous feeding and discharging, with low material loss and low overall energy consumption. Furthermore, the modified pulp has a high methyl cellulose content, a degree of polymerization that meets the lyocell-specific pulp index, and a low metal ion content. It also exhibits good swelling and dissolution effects in NMMO solution, and the final spinning dope has good spinnability and can be used to produce lyocell fibers.
[0048] III. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model includes a first inner tank for ensuring that the pulp is crushed in the solvent and that the pulp porridge is tumbled in the first inner tank; geared stirring blades for crushing the pulp in the solvent during stirring and stirring the pulp porridge to make the cellulose evenly impregnated in the solvent; stationary geared blades for cooperating with the geared stirring blades to crush the pulp in the solvent during stirring; and a first guide impeller 110 for assisting the pulp porridge to tumble from the first inner tank to the first outer tank.
[0049] IV. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model includes a second inner tank for ensuring that the pulp is crushed in the solvent and that the pulp porridge is tumbled in the second inner tank, an impeller 20715 for stirring the pulp porridge to make the cellulose impregnated evenly in the solvent, and a second guide impeller 209 for assisting the pulp porridge to tumble from the second inner tank to the second outer tank.
[0050] V. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model has a heat insulation layer 22 that provides stable temperature conditions for the device.
[0051] VI. The system for preparing lyocell fiber spinning dope by modifying wood pulp provided by this utility model includes a pre-pulverizer 23 for coarsely pulverizing the pressed pulp and a pulverizer 5 for finely pulverizing the pressed pulp.
[0052] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.
Claims
1. A system for preparing lyocell fiber spinning dope by modifying wood pulp, characterized in that: The apparatus includes an enzymatic hydrolysis purification vessel (1), a first washing vessel (2), a bleaching and impurity removal vessel (3), a second washing vessel (4), a pulverizer (5), a pulper (6), and a thin-film evaporator (7). The lower end of the enzymatic hydrolysis purification vessel (1) is connected to a first connecting pipe (8). A first conveying pump (9) and a first press (10) are installed on the first connecting pipe (8). The discharge end of the discharge trough of the first press (10) is located above the inlet of the first washing vessel (2). The lower end of the first washing vessel (2) is connected to a second connecting pipe (11). A second conveying pump (12) and a second press (13) are installed on the second connecting pipe (11). The discharge end of the discharge trough of the second press (13) is located above the inlet of the bleaching and impurity removal vessel (3). The lower end of the bleaching and impurity removal vessel (3) is connected to a third connecting pipe (14). The third connecting pipe (14) is equipped with a third conveying pump (15) and a third press (16). The discharge end of the discharge trough of the third press (16) is located above the inlet of the second washing kettle (4). The lower end of the second washing kettle (4) is connected to the fourth connecting pipe (17). The fourth connecting pipe (17) is equipped with a fourth conveying pump (18) and a fourth press (19). The discharge end of the fourth press (19) is connected to the inlet of the crusher (5). The discharge outlet of the crusher (5) is connected to the inlet of the pulper (6). The discharge outlet of the pulper (6) is connected to the fifth connecting pipe (20). The fifth connecting pipe (20) is equipped with a screw conveying pump (21). The discharge outlet of the screw conveying pump (21) is connected to the inlet of the thin film evaporator (7).
2. The system for preparing lyocell fiber spinning dope by modifying wood pulp according to claim 1, characterized in that: The enzymatic hydrolysis purification vessel (1) includes a first inner cylinder (101) and a first outer cylinder (102). The first inner cylinder (101) is fixedly disposed inside the first outer cylinder (102). A raw material inlet (103), a first liquid inlet pipe (104), and a first stirring motor (105) are disposed above the first outer cylinder (102). The first stirring motor (105) is connected to a first stirring shaft (106). The first stirring shaft (106) passes through the first outer cylinder (102) and enters the interior of the first outer cylinder (102). 06) Passing through the upper and lower ends of the first inner cylinder (101), the lower end of the first stirring shaft (106) is connected to the lower end of the inner wall of the first outer cylinder (102) through the bearing seat. Multiple toothed stirring blades (107) are provided on the first stirring shaft (106) inside the first inner cylinder (101). Multiple stationary toothed blades (108) are also fixedly provided inside the first inner cylinder (101). A first discharge port (109) is also provided at the lower end of the inner wall of the first outer cylinder (102). The first discharge port (109) is connected to the first connecting pipe (8).
3. The system for preparing lyocell fiber spinning dope by modifying wood pulp according to claim 2, characterized in that: A first guide impeller (110) is also provided on the first stirring shaft (106) at the lower end of the first inner cylinder (101).
4. The system for preparing lyocell fiber spinning dope by modifying wood pulp according to claim 3, characterized in that: The first washing tank (2), the bleaching and impurity removal tank (3), and the second washing tank (4) include a second inner cylinder (201) and a second outer cylinder (202). The second inner cylinder (201) is fixedly installed inside the second outer cylinder (202). A second feed inlet (203), a second liquid inlet pipe (204), and a second stirring motor (205) are provided above the second outer cylinder (202). The second stirring motor (205) is connected to a second stirring shaft (206). The second stirring shaft (206) passes through the second outer cylinder (202) and enters the second... Inside the outer cylinder (202), the second stirring shaft (206) passes through the upper and lower ends of the second inner cylinder (201). The lower end of the second stirring shaft (206) is connected to the lower end of the inner wall of the second outer cylinder (202) through a bearing seat. Multiple impellers (207) are provided on the second stirring shaft (206) inside the second inner cylinder (201). The lower end of the inner wall of the second outer cylinder (202) is also provided with a second discharge port (208). The second discharge port (208) is connected to the second connecting pipe (11), the third connecting pipe (14), or the fourth connecting pipe (17).
5. The system for preparing lyocell fiber spinning dope by modifying wood pulp according to claim 4, characterized in that: A second guide impeller (209) is also provided on the second stirring shaft (206) at the lower end of the second inner cylinder (201).
6. The system for preparing lyocell fiber spinning dope by modifying wood pulp according to claim 1, characterized in that: The outer sides of the enzymatic hydrolysis purification vessel (1), the first washing vessel (2), the bleaching and impurity removal vessel (3), the second washing vessel (4), and the pulper (6) are all provided with a heat insulation layer (22).
7. The system for preparing lyocell fiber spinning dope by modifying wood pulp according to claim 1, characterized in that: A pre-crusher (23) is also provided between the fourth press (19) and the crusher (5).
8. The system for preparing lyocell fiber spinning dope by modifying wood pulp according to claim 1, characterized in that: The pulper (6) includes a pulper outer cylinder (601), with a pulper inlet (602) and a pulp inlet pipe (603) at the upper end of the pulper outer cylinder (601), and a pulping shaft (604) at the lower end of the pulper outer cylinder (601). The pulping shaft (604) passes through the pulper outer cylinder and enters the pulper (6). A conical pulping body (605) is provided on the pulping shaft (604) inside the pulper (6), and a pulper outlet (606) is provided at the lower end of the pulper outer cylinder (601).
9. The system for preparing lyocell fiber spinning dope by modifying wood pulp according to claim 8, characterized in that: The pulping shaft (604) is provided with a first pulley (607) at the end away from the outer cylinder (601) of the pulper. The first pulley (607) is connected to the second pulley (610) on the pulping motor (609) through a transmission belt (608).
10. The system for preparing lyocell fiber spinning dope by modifying wood pulp according to claim 1, characterized in that: Valves (24) are provided on the first connecting pipe (8), the second connecting pipe (11), the third connecting pipe (14) and the fourth connecting pipe (17).