A bleaching system for lyocell fibers
The automated system of hydrogen peroxide bleaching device has solved the problems of chemical residues and environmental hazards in the bleaching of lyocell fibers, achieving efficient and low-consumption fiber bleaching effects and ensuring the stability of whiteness and fiber strength.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SAIDELI (CHANGZHOU) FIBER CO LTD
- Filing Date
- 2025-09-22
- Publication Date
- 2026-08-04
AI Technical Summary
Existing lyocell fiber bleaching technologies suffer from problems such as strong chemical residues, significant fiber damage, high environmental risks, and high energy and water consumption. Furthermore, traditional processes are inefficient, have large quality fluctuations, and are difficult to control whiteness stability.
The hydrogen peroxide bleaching device includes an alkali preparation unit, a bleaching mother liquor storage unit, and a bleaching circulation treatment unit. The automated system generates a bleaching circulating liquid for fiber bleaching, avoiding the use of chlorine-containing bleaching agents and simplifying the process to a single hydrogen peroxide bleaching step, thus reducing water consumption and energy consumption.
It achieves high whiteness bleaching of lyocell fibers with low chemical residue, minimal fiber damage, and good environmental performance, reducing the environmental pressure on enterprises. Furthermore, the automated control ensures the stability and safety of the bleaching process.
Smart Images
Figure CN224591189U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of fiber processing technology and relates to a bleaching system for lyocell fibers. Background Technology
[0002] Lyocell fiber is a type of regenerated cellulose fiber. It has the characteristics of good hand feel and easy dyeing. In particular, its physical and mechanical properties surpass those of ordinary viscose fiber. Moreover, the solvents used in the production process are non-toxic and recyclable, making it highly environmentally friendly.
[0003] For bleached lyocell fibers, the current mainstream bleaching technologies include a two-stage or multi-stage bleaching process: a sodium hypochlorite treatment unit followed by a hydrogen peroxide treatment unit. While this bleaching method, combining sodium hypochlorite with hydrogen peroxide through an oxidation reaction, can achieve good whiteness in washed products, it has the following limitations: strong chemical residues and high residue risks, which can damage the fibers; additionally, chlorine-containing bleaching agents can easily produce toxic, adsorbable organic halides, posing environmental hazards; high energy and water consumption, as the multi-stage heating and washing process leads to significant water resource consumption, placing a heavy burden on companies' environmental costs. Utility Model Content
[0004] To address the shortcomings of existing technologies, this application provides a bleaching system for lyocell fibers. The bleaching system described above can meet the bleaching requirements of lyocell fibers, with less chemical residue, less fiber damage, and reduced water and energy consumption.
[0005] This application provides a bleaching system for lyocell fibers, including a hydrogen peroxide bleaching device and a washing device; the hydrogen peroxide bleaching device includes: an alkali solution preparation unit, a bleaching mother liquor storage unit, and a bleaching circulation treatment unit;
[0006] The alkali solution preparation unit is used to mix alkaline salt and water to form an alkali solution of a certain concentration; the bleaching mother liquor storage unit is used to mix hydrogen peroxide and water to form and store a bleaching mother liquor of a certain concentration; the bleaching circulation treatment unit is equipped with a treatment device and a heating device. The treatment device has an inlet and an outlet. The inlet of the treatment device is connected to the alkali solution preparation unit and the bleaching mother liquor storage unit, respectively, to introduce alkali solution, bleaching mother liquor, and water to form a bleaching circulation liquid of a certain concentration. After the heating device heats the treatment device, the fed Lyocell fibers are bleached; the liquid obtained after bleaching is drawn out from the outlet and recycled.
[0007] The feed end of the washing device is connected to the discharge end of the bleaching circulation processing unit of the hydrogen peroxide bleaching device, and is used to wash the bleached Lyocell fibers with water.
[0008] In the embodiments of this application, the alkali preparation unit has an inlet and an outlet, and is equipped with a first water supply valve, a first flow meter and a stirring device.
[0009] In an embodiment of this application, the bleaching mother liquor storage unit has a tank-type structure and has a water inlet for water intake, a liquid inlet for hydrogen peroxide feed, and a liquid outlet, and is also equipped with a first liquid level gauge.
[0010] In the embodiments of this application, the bleaching circulation processing unit has a tank-type structure and is equipped with a second water supply valve and a second level gauge.
[0011] In the embodiments of this application, the heating device of the bleaching cycle processing unit is a steam heating device.
[0012] In the embodiments of this application, metering pumps are provided on the pipelines connecting the alkali preparation unit and the bleaching mother liquor storage unit to the processing equipment; a circulation pump is provided on the circulation pipeline at the outlet of the processing equipment.
[0013] In the embodiments of this application, the alkali preparation unit, the bleaching mother liquor storage unit, and the processing equipment are all equipped with automatic preparation units.
[0014] In an embodiment of this application, the washing device has a water inlet and a drain outlet.
[0015] In the embodiments of this application, the concentration of the bleaching circulating liquid in the bleaching circulating treatment unit is controlled at 0.8-1%, and the pH is controlled at 10-11.
[0016] In the embodiments of this application, the heating device of the bleaching cycle processing unit maintains the temperature of the processing equipment at 60-65°C.
[0017] The mainstream bleaching processes for lyocell fibers generally use chlorine-containing bleaching agents, which leave some chemical residues. Furthermore, traditional techniques are inefficient, exhibit significant quality fluctuations, have slow bleaching reactions, and are time-consuming. This makes it difficult to precisely control the uniformity and whiteness stability of lyocell fibers, impacting downstream dyeing quality and the competitiveness of finished products.
[0018] Compared with the prior art, the bleaching system provided in this application mainly uses a hydrogen peroxide bleaching device to bleach lyocell fibers. The hydrogen peroxide bleaching device includes an alkali preparation unit, a bleaching mother liquor storage unit, and a bleaching circulation treatment unit. The alkali preparation unit is used to mix alkaline salt and water to form an alkali solution of a certain concentration. The bleaching mother liquor storage unit is used to mix hydrogen peroxide and water to form a bleaching mother liquor of a certain concentration and store it. The bleaching circulation treatment unit is equipped with a processing device and a heating device. The processing device has an inlet and an outlet. The inlet of the processing device is connected to the alkali preparation unit and the bleaching mother liquor storage unit, respectively, to introduce alkali solution, bleaching mother liquor, and water to form a bleaching circulation liquid of a certain concentration. After the heating device heats the processing device, the fed lyocell fibers are bleached. The liquid obtained after bleaching is drawn out from the outlet and recycled. The bleaching system described in this application does not use chlorine-containing bleaching agents, but only hydrogen peroxide. The bleached lyocell fibers have no halogen residue, minimal fiber damage, and pose no environmental risks. This application simplifies the traditional bleaching process and system for lyocell fibers, requiring only one stage of hydrogen peroxide bleaching to meet bleaching requirements, while significantly reducing water consumption and lowering the environmental burden on enterprises.
[0019] Furthermore, the processing equipment of the alkali solution preparation unit, bleaching mother liquor storage unit, and bleaching circulation treatment unit described in this application embodiment are all equipped with automatic preparation units. Preparation can be completed simply by remotely setting parameters by the central control personnel, ensuring the stability and reliability of the preparation process of sodium hydroxide solution, bleaching mother liquor, and bleaching circulation liquid. No on-site personnel operation is required, avoiding potential safety hazards from direct contact with hydrogen peroxide and sodium hydroxide. This application embodiment automatically prepares the bleaching solution to bleach the fibers through automation, achieving a whiteness of over 88% for the bleached Lyocell fibers, with a whiteness increase of over 5%. Attached Figure Description
[0020] The exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings, and the above and other objectives, features and advantages of this application will become clearer.
[0021] Figure 1 This is a schematic diagram of a bleaching process system apparatus according to some embodiments of this application;
[0022] Figure 2 The whiteness after bleaching in Example 1 of this application;
[0023] Figure 3 The whiteness after bleaching is shown in Example 2 of this application. Detailed Implementation
[0024] Exemplary embodiments of the present application will now be described more fully with reference to the accompanying drawings. It should be understood that the exemplary embodiments described herein are provided merely to aid in understanding the present application and should not be construed as limiting the present application in any way. These embodiments are provided to make the description of the present application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The accompanying drawings are merely illustrative of the present application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.
[0025] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.
[0026] This application provides a bleaching system for lyocell fibers, including a hydrogen peroxide bleaching device and a washing device. The hydrogen peroxide bleaching device includes an alkali preparation unit, a bleaching mother liquor storage unit, and a bleaching circulation treatment unit. The alkali preparation unit is used to mix alkaline salt and water to form an alkali solution of a certain concentration. The bleaching mother liquor storage unit is used to mix hydrogen peroxide and water to form and store a bleaching mother liquor of a certain concentration. The bleaching circulation treatment unit is equipped with a treatment device and a heating device. The treatment device has an inlet and an outlet. The inlet of the treatment device is connected to the alkali preparation unit and the bleaching mother liquor storage unit, respectively, to introduce alkali solution, bleaching mother liquor, and water to form a bleaching circulation liquid of a certain concentration. After the heating device heats the treatment device, the fed lyocell fibers are bleached. The liquid obtained after bleaching is drawn out from the outlet and recycled.
[0027] The feed end of the washing device is connected to the discharge end of the bleaching circulation processing unit of the hydrogen peroxide bleaching device, and is used to wash the bleached Lyocell fibers with water.
[0028] The bleaching system for lyocell fibers described in this application can meet the bleaching requirements of the fibers, with less chemical residue and less fiber damage, while reducing water consumption and energy consumption.
[0029] See Figure 1 , Figure 1This is a schematic diagram of a bleaching process system apparatus according to some embodiments of this application. Wherein, 1 is an alkali preparation unit, 10 is an alkali metering pump; 2 is a bleaching mother liquor storage unit, 20 is a bleaching mother liquor metering pump; 3 is a bleaching circulation processing unit, 30 is a circulation pump.
[0030] The bleaching system described in this application is mainly used for lyocell fibers, which can be fiber yarns or various lyocell fabrics. The main component of the bleaching system is a hydrogen peroxide bleaching device for the bleaching stage, which includes an alkali preparation unit 1, a bleaching mother liquor storage unit 2, and a bleaching circulation processing unit 3.
[0031] In some embodiments of this application, the alkali preparation unit 1 is alkali-resistant, has an inlet for introducing sodium hydroxide and water, and an outlet; a metering pump 10 for alkali is installed on the outlet pipeline of the alkali preparation unit 1. Preferably, the alkali preparation unit 1 is equipped with a first water supply valve, a first flow meter, and a stirring device, and further includes an automatic preparation unit (the preparation of alkali can be completed by setting preparation parameters); the above-mentioned water supply valve, flow meter, etc. are not included in the... Figure 1 As shown in the figure. In the embodiments of this application, the alkaline salt involved is mainly sodium hydroxide (NaOH), which can be in solid form or in the form of sodium hydroxide solution. When sodium hydroxide solution is used, an alkaline solution addition valve can be provided; and the introduced water is generally demineralized water.
[0032] The specific operations of the alkali preparation unit 1 in the preferred embodiment of this application include:
[0033] (1) 1 m of demineralized water can be added to the alkaline solution preparation unit 1. 3 The system includes a control program that accumulates traffic up to 1MB / s. 3 The water supply valve will automatically close when needed;
[0034] (2) Start the stirrer in the alkali solution preparation unit 1, and add 0.2m of alkali solution with a mass concentration of 32%. 3 The cumulative flow reached 0.2m. 3 The alkali solution addition valve will automatically close, thus preparing an alkali solution with a mass concentration of 5-6%.
[0035] The bleaching mother liquor storage unit 2 in some embodiments of this application is oxidation-resistant and preferably has a tank-type structure, which can be simply referred to as a bleaching mother liquor storage tank, bleaching tank, etc. The bleaching mother liquor storage unit 2 has a water inlet for water intake, a liquid inlet for hydrogen peroxide feed, and a liquid outlet; hydrogen peroxide (hydrogen peroxide H2O2) and water (which can be process water or demineralized water) are introduced and mixed to form a bleaching mother liquor of a certain concentration and stored therein. Preferably, the liquid outlet pipeline of the bleaching mother liquor storage unit 2 is equipped with a bleaching mother liquor metering pump 20, which is also equipped with a first liquid level gauge and a corresponding automatic preparation unit for the bleaching mother liquor.
[0036] The specific operation of the bleaching mother liquor storage unit 2 in the preferred embodiment of this application includes:
[0037] (1) 2.5m of demineralized water can be added to the bleaching storage tank. 3 Add 1 ml of hydrogen peroxide. 3 Prepare a bleaching mother liquor with a mass concentration of 8%;
[0038] (2) During normal use, when the liquid level in the bleaching storage tank drops to 15%, prepare the bleaching mother liquor according to step (1).
[0039] In some embodiments of this application, the bleaching circulation processing unit 3 is equipped with processing equipment and heating equipment; wherein, the processing equipment is a tank-type structure with an inlet and an outlet, which can be referred to as a bleaching circulation tank. The inlet of the processing equipment is connected to the outlet of the alkali preparation unit 1 and the bleaching mother liquor storage unit 2 respectively, introducing alkali, bleaching mother liquor and water to form a bleaching circulation liquid of a certain concentration.
[0040] Preferably, the processing equipment is equipped with a second water supply valve, a second level gauge, and an automatic preparation unit, and a circulation pump 30 is installed on the outlet circulation pipeline. Specifically, the concentration of the bleaching circulating liquid can be controlled at 0.8-1%, and the pH can be controlled at 10-11, such as pH 10 or 11.
[0041] Furthermore, the heating equipment of the bleaching circulation treatment unit 3 is preferably a conventional steam heating equipment, which heats the treatment equipment, such as the bleaching circulation tank, and the temperature can be maintained at 60-65℃. In the treatment equipment, the fed lyocell fibers undergo bleaching treatment, and the resulting liquid is drawn out from its outlet and recycled. In this application embodiment, there are no special restrictions on the morphology and specifications of the lyocell fibers to be treated; they can be fiber yarns or various fabric forms. In some embodiments, the specifications of the fed lyocell fibers can be: 1.33dtex*38mm, 1.33dtex*32mm, 1.11dtex*38mm (fiber length between 32-38mm, conventional fineness). The feed rate of the lyocell fibers can be 6.5-10.5t / h; the bleaching treatment time is 2-4min, which can be adjusted according to the bleaching effect.
[0042] The specific operation of the bleaching cycle processing unit 3 in the preferred embodiment of this application includes:
[0043] (1) Open the demineralized water supply valve to add 2.5m of demineralized water to the bleaching circulation tank. 3 (Automatically closes the water supply valve when the liquid level reaches 50%);
[0044] (2) Turn on the steam heater of the bleaching circulation tank to raise the temperature of the bleaching circulation tank to 65°C and keep it warm;
[0045] (3) Start the bleaching metering pump 20 and add 0.3m of bleaching mother liquor to the bleaching circulation tank. 3 (Controlled by the cumulative flow value in the system), it is prepared into a 0.8-1% bleaching circulating solution;
[0046] (4) Start the bleaching circulation pump 30, start the alkali metering pump 10, add alkali to the bleaching circulation tank, and control the pH at 10-11.
[0047] (5) During normal production, the bleaching metering pump 20 continuously adds bleaching mother liquor to the bleaching circulation tank in a quantitative manner, and controls the concentration in the bleaching circulation tank to be between 0.8% and 1%.
[0048] The bleaching process described above corresponds to the bleaching stage, followed by a washing stage, after which the bleached fibers are obtained. The bleaching system for lyocell fibers described in this application includes a washing device, the feed end of which is connected to the discharge end of the bleaching circulation processing unit 3 of the hydrogen peroxide bleaching device, for adding water to wash the bleached lyocell fibers.
[0049] In embodiments of this application, the washing device has an inlet for introducing process water and a drain outlet for discharging wastewater, from which bleached lyocell fiber is produced. Specifically, the washing device includes a distribution tank, etc. Clean process water is introduced into the distribution tank in the washing section, overflowing from the top of the distribution tank onto the bleached fibers, thereby achieving a washing effect. Preferably, the distribution tank is a long, narrow water tank with a length consistent with the fiber distribution width, and a serrated top design to ensure uniform water overflow. In some embodiments, the washing flow rate of the washing device can be 35–45 m³ / h. 3 / h; water washing temperature is 55±5℃.
[0050] In summary, the bleaching system of this application embodiment does not use chlorine-containing bleaching agents, but only hydrogen peroxide for bleaching. The bleached lyocell fibers have no halogen residue, minimal fiber damage, and no environmental hazards. The bleaching process of this application embodiment is simplified, and the system structure is simple. Only one stage of hydrogen peroxide bleaching is needed to meet the bleaching requirements, while significantly reducing water consumption and lowering the environmental burden on enterprises. Furthermore, the processing equipment of the alkali solution preparation unit, bleaching mother liquor storage unit, and bleaching circulation treatment unit described in this application embodiment are all equipped with automatic preparation units. Preparation can be completed remotely by central control personnel by setting parameters, ensuring the stability and reliability of the preparation process of sodium hydroxide solution, bleaching mother liquor, and bleaching circulating liquid. No on-site personnel operation is required, avoiding potential safety hazards from direct contact with hydrogen peroxide and sodium hydroxide.
[0051] To better understand the technical content of this application, specific embodiments are provided below to further illustrate this application. The substances used in the embodiments of this application are commercially available.
[0052] The bleaching system for lyocell fibers includes a hydrogen peroxide bleaching unit and a washing unit, corresponding to the bleaching and washing process flows, respectively. The hydrogen peroxide bleaching unit includes an alkali preparation unit 1, a bleaching mother liquor storage unit 2 (bleaching tank), and a bleaching circulation treatment unit 3. The bleaching circulation treatment unit is equipped with a bleaching circulation tank and steam heating equipment. The bleaching circulation tank has an inlet and an outlet, with the inlet connected to the alkali preparation unit 1 and the bleaching mother liquor storage unit 2, respectively. The feed end of the washing unit is connected to the discharge end of the bleaching circulation treatment unit 3 of the hydrogen peroxide bleaching unit.
[0053] Metering pump 10 and metering pump 20 are respectively installed on the connecting pipelines of the alkali preparation unit 1, the bleaching mother liquor storage unit 2, and the bleaching circulation tank; a circulation pump 30 is installed on the circulation pipeline at the outlet of the bleaching circulation tank. Furthermore, the alkali preparation unit 1, the bleaching mother liquor storage unit 2, and the bleaching circulation tank are all equipped with automatic preparation units.
[0054] Clean process water is introduced into the distribution tank in the washing section, overflowing from the top of the tank onto the bleached fibers for washing. The distribution tank is a long, narrow water tank, the length of which matches the width of the fiber distribution, with a serrated top design. Before the process water enters the distribution tank, there is a steam plate heat exchanger and a flow regulating valve to adjust the temperature and flow rate of the process water. The washing flow rate is 35–45 m³ / h. 3 / h; water washing temperature is 55±5℃.
[0055] Among them, 1m of demineralized water was added to the alkaline solution preparation unit 1. 3 The system includes a control program that accumulates traffic up to 1MB / s. 3 The water supply valve will automatically close; start the stirrer in the alkali solution preparation unit 1 and add 0.2 ml of 32% alkali solution. 3 .
[0056] Add 2.5m of demineralized water to the bleaching storage tank. 3 Add 1 ml of hydrogen peroxide. 3 Prepare a bleaching mother liquor with a mass concentration of 8%. During normal use, when the liquid level in the bleaching storage tank drops to 15%, prepare the bleaching mother liquor according to the above steps.
[0057] Bleaching circulation tank operation:
[0058] (1) Open the demineralized water supply valve and add 2.5m of demineralized water to the bleaching circulation tank. 3 (Automatically closes the water supply valve when the liquid level reaches 50%);
[0059] (2) Turn on the steam heater of the bleaching circulation tank to raise the temperature of the bleaching circulation tank to 60-65℃ and keep it warm;
[0060] (3) Start the bleaching metering pump 20 and add 0.3m of bleaching mother liquor to the bleaching circulation tank. 3 (Controlled by the cumulative flow value in the system), it is prepared into a 0.8-1% bleaching circulating solution;
[0061] (4) Start the bleaching circulation pump 30 and the alkali metering pump 10, and add alkali to the bleaching circulation tank to control the pH at 10-11.
[0062] (5) During normal production, the bleaching metering pump 20 continuously adds bleaching mother liquor to the bleaching circulation tank in a quantitative manner, and controls the concentration in the bleaching circulation tank to be between 0.8% and 1%.
[0063] Example 1
[0064] Using the bleaching system described above, the main experiment focused on the effect of different hydrogen peroxide concentrations at the same pH level.
[0065] A. Experimental conditions: The pH of the bleaching circulating solution was kept constant at 10, and the temperature was kept constant at 65℃. By adjusting the hydrogen peroxide concentration, the whiteness and strength of the bleached fibers were tested to explore the optimal hydrogen peroxide concentration.
[0066] B. Experimental data are shown in Table 1 and Figure 2 ;
[0067] C. Experimental Conclusions
[0068] When the pH of the bleach solution is fixed at 10 and the temperature of the bleaching circulating solution is fixed at 65℃, the optimal bleach concentration is 10-12 g / L (the bleach concentration mentioned here refers to the concentration of the solution in the bleaching circulating tank). The whiteness after bleaching can reach 88% (FZ / T 50013, standard of the textile industry, unit is %). Further increasing the bleach concentration will not significantly improve the bleaching effect.
[0069] Table 1. Bleaching treatment results of Example 1
[0070] a1 blank sample / 65 82.3 a2 blank sample / 65 82.5 b1 4 10 65 83.7 b2 4 10 65 83.4 c1 6 10 65 85.1 c2 6 10 65 85 d1 8 10 65 87.5 d2 8 10 65 87.9 e1 10 10 65 88.5 e2 10 10 65 88.6 f1 12 10 65 88.5 f2 12 10 65 89 g1 16 10 65 89.1 g2 16 10 65 88.6
[0071] In addition, fiber damage: the strength of the bleached fibers was tested. When the fiber damage was severe, the fiber strength would decrease significantly. In the embodiments of this application, the fiber strength decreased by ≤5% after bleaching, and the strength after bleaching was still far higher than the national standard.
[0072] Example 2
[0073] Using the bleaching system described above, the main experiment was to investigate the effect of different pH values on the bleaching effect at the same bleach concentration.
[0074] A. Experimental conditions: The concentration of the bleaching circulating solution was fixed at 10 g / L, and the temperature was fixed at 65℃. By adjusting the pH of the bleaching solution, the whiteness and strength of the bleached fibers were tested to explore the optimal pH range.
[0075] B. Experimental data are shown in Table 2 and Figure 3 ;
[0076] C. Experimental Conclusions
[0077] When the concentration of the bleach is fixed at 10 g / L and the temperature is fixed at 65°C, the optimal pH of the bleach is 10–11.
[0078] Table 2. Bleaching treatment results of Example 2
[0079] a1 blank sample / 65 82.6 a2 Empty self-sample / 65 82.4 b1 10 9 65 83.6 b2 10 9 65 83.5 c1 10 9.5 65 84.5 c2 10 9.5 65 84.8 d1 10 10 65 88.5 d2 10 10 65 88.4 e1 10 10.5 65 88.7 e2 10 10.5 65 88.6 f1 10 11 65 89 f2 10 11 65 88.7 g1 10 12 65 88.2 g2 10 12 65 88.1
[0080] As can be seen from the above embodiments, the bleaching system for lyocell fibers in this application embodiment does not use chlorine-containing bleaching agents, but only hydrogen peroxide for bleaching. The bleached lyocell fibers have no halogen residue, minimal fiber damage, and no environmental hazards. This application simplifies the traditional bleaching process and system for lyocell fibers, requiring only one stage of hydrogen peroxide bleaching to meet bleaching requirements, while significantly reducing water consumption and lowering the environmental burden on enterprises. Furthermore, the processing equipment in the alkali solution preparation unit, bleaching mother liquor storage unit, and bleaching circulation treatment unit described in this application embodiment is equipped with an automatic preparation unit. Preparation can be completed remotely by central control personnel by setting parameters, ensuring the stability and reliability of the preparation process of sodium hydroxide solution, bleaching mother liquor, and bleaching circulation liquid. No on-site personnel operation is required, avoiding potential safety hazards from direct contact with hydrogen peroxide and sodium hydroxide. This application embodiment automatically prepares the bleaching solution to bleach the fibers through automation, achieving a whiteness of over 88% for the bleached lyocell fibers, with a whiteness increase of over 5%.
[0081] This application has been described with reference to specific embodiments, but those skilled in the art will understand that various changes and equivalent substitutions can be made without departing from the scope of this application. Furthermore, numerous modifications can be made to this application to suit specific occasions or materials without departing from its protection scope. Therefore, this application is not limited to the specific embodiments disclosed herein, but includes all embodiments falling within the protection scope of the claims.
Claims
1. A bleaching system for lyocell fibers, characterized in that, It includes a hydrogen peroxide bleaching device and a water washing device; the hydrogen peroxide bleaching device includes: an alkali solution preparation unit, a bleaching mother liquor storage unit, and a bleaching circulation treatment unit; The alkali solution preparation unit is used to mix alkaline salt and water to form an alkali solution of a certain concentration; the bleaching mother liquor storage unit is used to mix hydrogen peroxide and water to form and store a bleaching mother liquor of a certain concentration; the bleaching circulation treatment unit is equipped with a treatment device and a heating device. The treatment device has an inlet and an outlet. The inlet of the treatment device is connected to the alkali solution preparation unit and the bleaching mother liquor storage unit, respectively, to introduce alkali solution, bleaching mother liquor, and water to form a bleaching circulation liquid of a certain concentration. After the heating device heats the treatment device, the fed Lyocell fibers are bleached; the liquid obtained after bleaching is drawn out from the outlet and recycled. The feed end of the washing device is connected to the discharge end of the bleaching circulation processing unit of the hydrogen peroxide bleaching device, and is used to wash the bleached Lyocell fibers with water.
2. The bleaching system according to claim 1, characterized in that, The alkali preparation unit has a feed inlet and a liquid outlet, and is equipped with a first water supply valve, a first flow meter and a stirring device.
3. The bleaching system according to claim 1, characterized in that, The bleaching mother liquor storage unit has a tank-type structure and has a water inlet for water intake, a liquid inlet for hydrogen peroxide feed, and a liquid outlet, and is also equipped with a first liquid level gauge.
4. The bleaching system according to claim 1, characterized in that, The bleaching circulation treatment unit has a tank-type structure and is equipped with a second water supply valve and a second level gauge.
5. The bleaching system according to claim 1, characterized in that, The heating device for the bleaching cycle processing unit is a steam heating device.
6. The bleaching system according to any one of claims 1-5, characterized in that, Metering pumps are installed on the pipelines connecting the alkali preparation unit and the bleaching mother liquor storage unit to the treatment equipment; a circulation pump is installed on the circulation pipeline at the outlet of the treatment equipment.
7. The bleaching system according to any one of claims 1-5, characterized in that, The alkali preparation unit, bleaching mother liquor storage unit, and processing equipment are all equipped with automatic preparation units.
8. The bleaching system according to any one of claims 1-5, characterized in that, The washing device has a water inlet and a sewage outlet.
9. The bleaching system according to any one of claims 1-5, characterized in that, The concentration of the bleaching circulating solution in the bleaching circulating treatment unit is controlled at 0.8-1%, and the pH is controlled at 10-11.
10. The bleaching system according to any one of claims 1-5, characterized in that, The heating device of the bleaching cycle processing unit maintains the temperature of the processing equipment at 60-65°C.