A viscose filament multi-ply production waste glue recovery method, system and control system thereof

Abstract

The application discloses a viscose filament multi-ply production waste glue recycling method and system and a control system thereof, waste glue is collected, pre-filtered and filtered in stages and then reused in spinning, the viscose filament recycling system comprises a viscose filtering section, a waste glue collecting tank A, a pre-filtering unit, a staged filtering unit and a defoaming section, a continuous path for waste glue generation, treatment and reuse is formed between the viscose filtering section, the waste glue collecting tank A, the pre-filtering unit, the staged filtering unit and the defoaming section, and the waste glue recycling system is automatically controlled, the waste glue is collected by the waste glue collecting tank, pre-filtered by the pre-filtering unit and filtered in stages by the staged filtering unit and then reused in viscose filament production.

Description

Technical Field

[0001] This invention relates to the field of viscose filament technology in the textile industry, and particularly to a method, system and control system for waste adhesive recycling in multi-sizing production of viscose filament. Background Technology

[0002] In the viscose filament industry, cost considerations necessitate the use of mixed pulps such as softwood pulp, hardwood pulp, and bamboo pulp in production. This results in a multi-pulp production system where different pulp types exhibit significant differences in their properties. For instance, the fiber length of softwood pulp is 3-5 times that of hardwood pulp, while bamboo pulp and recycled pulp have higher levels of foreign fibers due to their raw material characteristics. The combined use of multiple pulps leads to uneven yellowing reactions, directly resulting in increased waste adhesive from filtration in subsequent processes. This waste adhesive is generated in the viscose filtration section, primarily from: KKF filter backwash waste adhesive (80%), plate and frame filter chamber cleaning adhesive (15%), and KKF filter maintenance filter replacement chamber adhesive (5%). The filtration system generates a large amount of waste adhesive containing high particle counts, ash, unbulked fibers, and large particles of synthetic fiber dust. Simple filtration methods are insufficient for purification, resulting in low recycling value and requiring periodic discharge. This creates environmental pressure and represents a waste of resources. Therefore, it is necessary to study a waste glue recycling system for use in multi-sizing filament production systems, which can effectively reduce the cost of sizing and alkali used in filament production.

[0003] Currently, the main methods for treating waste adhesive from viscose filament are as follows: 1. Using a disc separator. The waste adhesive is separated from insoluble impurities using a disc separator before entering the viscose staple fiber production system. Its disadvantages are that recycling waste adhesive for staple fiber is less economical than recycling it for filament, and it requires both filament and staple fiber to be in production simultaneously, which has certain limitations. II. Plate and frame filter press filtration and recovery. Multi-slurry systems have a relatively large amount of waste adhesive and a higher impurity content (particle count usually > 50,000 particles / ml). Using a plate and frame filter press to process waste adhesive results in rapid filter clogging, a large number of disassemblies, a significant waste of adhesive, and the disassembly and assembly of plate filters is a labor-intensive operation with high labor costs. III. KKF ​​Filter Recycling. Directly using a KKF filter to filter waste adhesive will generate a large amount of secondary waste adhesive, resulting in waste. Due to the high viscosity and numerous impurities in the waste adhesive, its filtration performance is extremely poor, resulting in a very small amount of waste adhesive filtered per unit time (less than 0.5 cubic meters / hour). The KKF filter cannot guarantee the backwash pressure during automatic backwashing, thus failing to achieve the backwashing effect and unable to perform normal filtration. Therefore, it is difficult to choose a KKF automatic filter for filtration.

[0004] In addition, a Chinese patent document discloses a method for recycling waste adhesive in viscose production (patent publication number: CN105369394B). This method involves pre-treating the waste adhesive by adding alkaline solution to reduce the alkali content to 6-8%. This diluted waste adhesive aims to solve problems such as difficult filtration, low filtration efficiency, and low waste adhesive recovery rate of KKF filters during waste adhesive recycling. However, this method is clearly unsuitable for multi-sizing filament production systems because adding alkaline solution during waste adhesive pre-treatment cannot effectively stabilize relevant quality indicators of the waste adhesive (methyl cellulose content, viscosity, degree of esterification, surface tension, degree of maturity, alkali content, etc.). Reusing it in large-scale production would disrupt normal viscose production and cause quality fluctuations.

[0005] Chinese patent literature discloses a waste adhesive recycling system (patent publication number: CN206232870U). This scheme employs different treatment processes for different types of waste adhesives, then mixes them after treatment. The waste adhesive, after filtration, is directly added to normal viscose and enters the viscose mass production system for viscose filament production, thus solving the problem of the impact of recycled waste adhesive on the spinnability of filaments. However, when it is necessary to purify filaments containing various types of impurities with large diameters and hard textures, small diameter impurities, and elastic gel particles, it is not possible to separate and treat these impurities of different compositions and diameters using different treatment methods before mixing. Summary of the Invention

[0006] To address the problems of large quantities of waste adhesive generated in existing technologies, containing high particle counts, ash content, unswollen fibers, and large particles of chemical fiber dust, which are difficult to purify using simple filtration methods, have low recycling value, require periodic discharge, and pose environmental pressures, this invention provides a method, system, and control system for waste adhesive recycling in multi-sizing viscose filament production. This invention not only enables the phased collection, filtration, and purification of various waste adhesives generated during viscose filament production for reuse in filament production, effectively ensuring the stability of viscose filament product quality; but also guarantees the sustainability, adjustability, and automated control of the waste adhesive recycling process.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for recycling waste adhesive in the production of multi-sizing viscose filaments, characterized in that it includes: a: Collection, collecting the waste adhesive generated during the production of viscose filament multi-sizing agents and temporarily storing it in a waste adhesive collection tank; The waste adhesive contains: 8.17±0.1% methyl methacrylate, 5.80±0.1% alkali, 30-90s viscosity, 9.5-12.5mL maturity, >50,000 particles / mL, >700 fibers / gram under microscopic examination, and <15ml / min filtration rate. b: Pre-filtration: The waste glue in the waste glue collection tank is passed into the pre-filtration unit. The pre-filtration unit is a fully automatic online backwashing KKF filter with a filtration accuracy of 15~40μm metal sintered filter screen. The pressure difference between the inlet and outlet of the pre-filtration unit is controlled to be ≤3.5bar to obtain pre-filtered waste glue and secondary waste glue. Among them, the waste adhesive after pre-filtration by the pre-filtration unit is controlled to have the following particle counts: 5000-6000 particles / ml, microscopic value of 160-260 particles / gram, and filtration rate of 65-90 ml / min; c: Cascade filtration: The pre-filtered waste adhesive is passed into a cascade filtration unit, which includes a primary plate and frame filter, a secondary plate and frame filter, and a tertiary plate and frame filter connected in series. The primary plate and frame filter has a filtration accuracy of 30–45 μm; the secondary plate and frame filter has a filtration accuracy of 15–30 μm; and the tertiary plate and frame filter has a filtration accuracy of 8–15 μm. The pressure difference between the inlet and outlet of the cascade filtration unit is controlled to be ≤12 bar. The waste adhesive filtered by the cascade filtration unit is then obtained, yielding recycled adhesive I and secondary waste adhesive. The waste adhesive filtered by the cascade filtration unit is controlled to have the following properties: cellulose content 8.17±0.1%, alkali content 5.80±0.1%, viscosity 30–90 s, maturity 9.5–12.5 mL, particle count <1000 particles / mL, microscopic examination value ≤30 particles / gram, and filtration rate ≥110 mL / min. d: Reuse, the recycled adhesive I is directly fed into the degassing device in the viscose filament production system, and after degassing and pre-spinning filtration, it is spun; e: Secondary waste adhesive recycling: The secondary waste adhesive generated by the pre-filtration unit and the cascade filtration unit is collected, filtered by a plate and frame filter press to obtain recycled adhesive II, and then fed into the degassing device of the viscose filament production system.

[0008] Accordingly, the present invention also provides a waste adhesive recycling system in a viscose filament production system to implement the above-mentioned waste adhesive recycling method; the system includes a viscose filtration section, a waste adhesive collection tank A, a pre-filtration unit, a cascade filtration unit, a secondary waste adhesive recycling unit, and a degassing section, with each unit forming a continuous pathway for waste adhesive generation, treatment, and reuse; the waste adhesive collection tank A is connected to the inlet of the pre-filtration unit through a conveying pipe I; the pre-filtration unit is provided with at least two units, arranged in parallel, and is a fully automatic online backwashing KKF filter with a built-in filtration accuracy of 15-40μm. It is a sintered filter screen; the pre-filtration unit is connected to the inlet of the cascade filtration unit through conveying pipe II; at least two cascade filtration units are provided, connected to each other through conveying pipe III; each cascade filtration unit includes a first-stage plate and frame filter, a second-stage plate and frame filter, and a third-stage plate and frame filter connected in series, wherein the filter cloth structure of the first-stage plate and frame filter includes one layer of polypropylene and one layer of plain cloth, the filter cloth structure of the second-stage plate and frame filter includes one layer of polypropylene, one layer of double fleece, one layer of plain cloth, and one layer of poplin, and the filter cloth structure of the third-stage plate and frame filter includes one layer of polypropylene, one layer of double fleece, and one layer of plain cloth. And two layers of poplin; the secondary waste glue recycling unit includes a waste glue collection tray A set at the bottom of the pre-filtration unit, a waste glue collection tray B set at the bottom of the cascade filtration unit, and a secondary filtration unit; the outlet end of the waste glue collection tray A is connected to the waste glue collection tank B through a conveying pipe IV, and the outlet end of the waste glue collection tray B is connected to the waste glue collection tank B through a conveying pipe V; the outlet end of the waste glue collection tank B is connected to the secondary filtration unit through a conveying pipe VI, and the discharge port of the secondary filtration unit and the discharge port of the cascade filtration unit are connected to the degassing section after being converged by pipelines; the Waste glue buffer tank A is installed on conveying pipe II. The upper inlet of waste glue buffer tank A is connected to the pre-filtration unit through conveying pipe II, and the bottom outlet is connected to the cascade filtration unit through conveying pipe II. Each stage outlet of the cascade filtration unit is connected to waste glue buffer tank B. The upper inlet of waste glue buffer tank B is connected in series with the previous stage filtration unit through a pipeline, and the bottom outlet is connected in series with the next stage filtration unit through a pipeline. The outlet of the secondary filtration unit is connected to waste glue buffer tank C through conveying pipe VI. Waste glue buffer tank B and waste glue buffer tank C are connected in series to the degassing section.

[0009] This invention also provides a waste adhesive recycling control system in a viscose filament production system. The system is configured in the aforementioned viscose filament waste adhesive recycling system. The waste adhesive recycling control system includes a pre-filtration control unit located in the pre-filtration unit, a cascade filtration control unit located in the cascade filtration unit, a human-machine interface, and a PLC controller. The pre-filtration control unit and the cascade filtration control unit are bidirectionally electrically connected to the PLC controller, and the human-machine interface is also bidirectionally electrically connected to the PLC controller. The pre-filtration control unit includes a flow meter AI, a glue supply pump AI, and an automatic regulating valve AI located on the delivery pipe I. The flow meter AI, glue supply pump AI, and automatic regulating valve AI are located at the inlet end of the pre-filtration unit. Pressure transmitter AI is installed at both the inlet and outlet ends of each KKF filter in the pre-filtration unit. The flow meter AI, glue supply pump AI, automatic regulating valve AI, and pressure transmitter AI are all electrically connected to the PLC controller. The cascade filtration control unit includes a flow meter BI, a glue supply pump BI, a pressure transmitter BI, and an automatic regulating valve BI. The flow meter BI, glue supply pump BI, and pressure transmitter AI are all electrically connected to the PLC controller. I. Pressure transmitter BI and automatic regulating valve BI are installed on conveying pipe II and are both electrically connected to the PLC controller; the outlet end of waste glue collection tray A at the bottom of the pre-filtration unit is connected to waste glue collection tank C through conveying pipe IV, and the outlet end of waste glue collection tray B at the bottom of the cascade filtration unit is connected to waste glue collection tank C through conveying pipe V; both conveying pipe IV and conveying pipe V are equipped with glue supply pump CI, and the outlet end of the waste glue collection tank C is connected to the secondary filtration unit through conveying pipe VI, which is equipped with glue supply pump CII; The glue supply pumps CI and CII are electrically connected to the PLC controller; the waste glue buffer tanks B and C are connected through a delivery pipe VII, and a glue supply pump BIII is installed on the delivery pipe VII; a level transmitter I is installed on the upper part of each of the waste glue buffer tanks A, B, and C, and the level transmitter I is electrically connected to the PLC controller; a level transmitter II is installed on the upper part of each of the waste glue collection tanks A and C, and the level transmitter II is electrically connected to the PLC controller.

[0010] In summary, the beneficial effects of this invention are as follows: 1. Collect the waste adhesive generated in viscose production and reuse the filtered and purified waste adhesive in the viscose filament production system. Compared with using the waste adhesive for staple fiber production, the economic benefits are higher. The secondary waste adhesive in the waste adhesive recycling process can also be recycled and reused.

[0011] 2. By combining various filter types, impurities in waste glue are intercepted in stages and multiple times, which can effectively ensure the stability of the spinning process and product quality.

[0012] 3. To achieve automated control of the waste adhesive generated in the adhesive filtration section, which is then processed through the pre-filtration unit and the cascade filtration unit before entering the degassing section, thus forming a continuous path for the generation, treatment and reuse of waste adhesive. This enables a continuous, efficient and stable production process, reduces manual intervention and improves production efficiency. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a waste glue recycling system.

[0014] Figure 2 Schematic diagram of the pre-filter unit structure.

[0015] Figure 3 This is a schematic diagram of a cascade filter unit.

[0016] Figure 4 This is a schematic diagram of the secondary filtration unit.

[0017] Figure 5 This is a schematic diagram of the waste glue recycling process.

[0018] Figure 6 This is a schematic diagram of the secondary waste glue recycling process.

[0019] Figure 7 This is a flowchart of the automatic backwashing process.

[0020] Figure 8 This is a circuit diagram for automatic backwashing control.

[0021] The annotations in the attached figures are explained as follows: 1. Waste glue collection tank A; 11. Delivery pipe I; 111. Flow meter AI; 112. Glue supply pump AI; 113. Automatic regulating valve AI; 114. Pressure transmitter AI; 12. Delivery pipe II; 121. Flow meter BI; 122. Glue supply pump BI; 123. Pressure transmitter BI; 124. Automatic regulating valve BI; 2. Pre-filtration unit; 21. Waste glue collection tray A; 22. Waste glue buffer tank A; 221. Level transmitter I; 3. Cascade filtration unit; 31. Delivery pipe III; 311. Glue supply pump BII; 312. Pressure transmitter BII; 313. Automatic regulating valve BII; 32. Waste glue collection tray B; 33. Waste glue buffer tank B; 34. Delivery pipe VII; 341. Glue supply pump BIII; 4. Secondary waste glue recycling unit; 42. Secondary filtration unit; 43. Waste glue collection tank C; 431. Level transmitter II; 44. Waste glue buffer tank C; 45. Delivery pipe IV; 51. Glue supply pump CI; 46. Delivery pipe V; 47. Delivery pipe VI; 471. Glue supply pump CII; 5. Adhesive filtration section; 6. Defoaming section. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the embodiments.

[0023] Example 1: This embodiment provides a waste adhesive recycling system in a viscose filament production system. The viscose filament recycling system includes a viscose filtration section 5, a waste adhesive collection tank A1, a pre-filtration unit 2, a cascade filtration unit 3, and a degassing section 6, forming a continuous pathway for waste adhesive generation, treatment, and reuse. The waste adhesive collection tank A1 is connected to the inlet of the pre-filtration unit 2 via a conveying pipe I11, and the pre-filtration unit 2 is connected to the inlet of the cascade filtration unit 3 via a conveying pipe II12. At least two pre-filtration units 2 are provided and connected in parallel. At least two cascade filtration units 3 are provided and connected via a conveying pipe III31.

[0024] Figure 1 The diagram shows a viscose filtration section 5, a waste glue collection tank A1, a pre-filtration unit 2, a cascade filtration unit 3, and a degassing section 6. The waste glue collection tank A1 is used to store waste glue collected during the production of multi-sizing filaments. The waste glue collected in the waste glue collection tank A1 is filtered and purified sequentially through the pre-filtration unit 2 and the cascade filtration unit 3. The pre-filtration unit 2 includes a KKF filter, which is a fully automatic online backwashing filter. The waste glue collection tank A1 transports the collected waste glue to the KKF filter for pre-filtration. After the pre-filtration unit 2 intercepts larger diameter and harder impurities in the waste glue, the cascade filtration unit 3 further filters the waste glue. The cascade filtration unit 3 requires multiple plate and frame filters. Even after pre-filtration, the waste glue still contains impurities with smaller diameters and some elastic gel particles. The waste glue filtered by the cascade filtration unit 3 can be reused in the production of viscose filaments.

[0025] The combined use of various pulps can lead to poor uniformity in the xanthation reaction, resulting in an increase in filtration waste in subsequent processes. A waste glue collection tank connected to a waste glue delivery pipeline transports the waste glue from production to pre-filtration unit 2. Pre-filtration unit 2 first intercepts large-diameter impurities in the waste glue, such as inorganic insoluble impurities, resin particles, and incompletely xanthated cellulose particles. This pre-filtration stage intercepts a large amount of impurities, and the pre-filtration equipment uses an online automatic backwashing filter to improve production efficiency, extend the cleaning and replacement cycle of filter cloths in subsequent filtration processes, and reduce production costs. The pre-filtered waste glue cannot be used directly and is then transported to a cascade treatment unit. Based on the filtration status and specific waste glue quality parameters, multi-stage plate and frame filters are used for further filtration and purification. In summary, multi-stage purification and eventual recycling of waste glue in the filtration system overcomes the challenges of large amounts of filtration waste glue, high production costs, and high wastewater discharge caused by the inherent differences in pulp types when using multiple pulps.

[0026] The pre-filtration equipment selected is a fully automatic online backwashing filter (KKF filter) because directly using a plate and frame filter press to filter waste adhesive would generate a large amount of secondary waste adhesive, resulting in waste. Due to the high impurity content of the waste adhesive, its filtration performance is poor, the filter cloth of the plate and frame filter press becomes clogged quickly, and the filtration flux declines significantly in a short period. It is difficult to balance the amount of adhesive passed and the filtration quality, requiring manual disassembly and cleaning of the filter press to restore filtration capacity. This method is labor-intensive, has high equipment occupancy rates, and the disassembly, assembly, and cleaning of the filter cloth also generates secondary waste adhesive, reducing the overall waste adhesive recovery efficiency. By installing a KKF filter pre-filtration system before the plate and frame filter press in the waste adhesive cascade purification system, using a sintered metal filter screen with a filtration accuracy of 15–40 μm, the impurities entering the plate and frame filter press can be effectively reduced. The KKF filter backwash waste adhesive outlet is connected to a secondary waste adhesive collection tank, resulting in high secondary waste adhesive recovery efficiency.

[0027] Example 2 In implementation, the tiered filtration unit 3 is configured in a tiered manner, consisting of a primary plate and frame filter, a secondary plate and frame filter, and a tertiary plate and frame filter. The tiered filtration unit 33 can be configured to include 2-4 stages or more, combined with the filter cloth precision to achieve the purpose of tiered filtration. Using a sintered metal filter screen with a screen precision of 15-40μm as the filter medium, high-throughput waste adhesive filtration is achieved. This process requires no manual intervention during operation, except for manual filter screen replacement according to production needs. It intercepts larger diameter and harder impurities in the waste adhesive, reducing the frequency of filter cleaning in subsequent filtration processes and saving production costs. Primary, secondary, and tertiary plate and frame filters are then set up, with multiple plate and frame filters connected in parallel at each stage, paired with specific filter cloth structures. Filter cloth structures include polypropylene felt, plain cloth, double fleece, and poplin, etc. Depending on actual needs, the filter cloth structure can be multi-layered, and the filter material in the filter cloth structure can be flexibly adjusted. The filtration precision increases progressively, meeting the filtration throughput while balancing the filter load, and is used to intercept smaller diameter impurities and some elastic gel particles in the waste adhesive.

[0028] Optionally, the filter cloth structure of the primary plate and frame filter press includes one layer of polypropylene and one layer of plain cloth; the filter cloth structure of the secondary plate and frame filter press includes one layer of polypropylene, one layer of double fleece, one layer of plain cloth, and one layer of poplin; and the filter cloth structure of the tertiary plate and frame filter press includes one layer of polypropylene, one layer of double fleece, one layer of plain cloth, and two layers of poplin. This combination of three plate and frame filters allows for multiple stages of interception of impurities in the waste rubber, ensuring the stability of the spinning process and product quality.

[0029] The primary filtration accuracy is 30–45 μm, the secondary filtration accuracy is 15–30 μm, and the tertiary filtration accuracy is 8–15 μm. Post-filtration parameters are primarily evaluated based on the number of adhesive particles (particles / ml), microscopic examination value (particles / gram), and filtration efficiency (ml / min). The post-filtration parameters during pre-filtration and cascade filtration are as follows:

[0030] This embodiment differs from Embodiment 1 in that the viscose filament recycling system also includes a secondary waste adhesive recycling unit 4. The secondary waste adhesive recycling unit 4 includes a waste adhesive collection tray A21 located at the bottom of the pre-filtration unit 2, a waste adhesive collection tray B32 located at the bottom of the cascade filtration unit 3, and a secondary filtration unit 42. The outlet end of the waste adhesive collection tray A21 is connected to the waste adhesive collection tank B43 via a conveying pipe IV45. The outlet end of the waste adhesive collection tray B32 is connected to the waste adhesive collection tank B via a conveying pipe V46. The outlet end of the waste adhesive collection tank B43 is connected to the secondary filtration unit 42 via a conveying pipe VI47. The discharge port of the secondary filtration unit 42 and the discharge port of the cascade filtration unit 3 are connected to the degassing section 6 via pipelines.

[0031] Example 3: In this embodiment, a waste glue buffer tank A22 is provided on the conveying pipe II12. The upper inlet of the waste glue buffer tank A22 is connected to the pre-filtration unit 2 through the conveying pipe II12, and the bottom outlet of the waste glue buffer tank A22 is connected to the cascade filtration unit 3 through the conveying pipe II12. The outlet of each cascade filtration unit 3 is connected to a waste glue buffer tank B33. The upper inlet of the waste glue buffer tank B33 is connected in series with the previous cascade filtration unit 3 through a pipeline, and the bottom outlet of the waste glue buffer tank B33 is connected in series with the next cascade filtration unit 3 through a pipeline. The outlet of the secondary filtration unit 42 is connected to the waste glue buffer tank C44 through the conveying pipe VI47. The waste glue buffer tank B33 is connected in series with the waste glue buffer tank C44 and then connected to the degassing section 6.

[0032] KKF filters and plate and frame filters are commonly used filtration equipment. They remove solid particles or impurities from waste adhesives through filtration, ensuring the quality of the waste adhesives. Although multiple filtrations of the yellowed and dissolved adhesives can reduce the impurity content in the adhesives to meet the requirements of subsequent spinning production processes, the filtration process inevitably generates waste adhesives. Therefore, they need to be collected and treated. The secondary waste adhesives generated by KKF filters and plate and frame filters can be recycled and treated using the methods described above.

[0033] Example 4: This embodiment provides a waste adhesive recycling control system in a viscose filament production system. The waste adhesive recycling control system includes a pre-filtration control unit in the pre-filtration unit 2, a cascade filtration control unit in the cascade filtration unit 3, a human-machine interface, and a PLC controller. The pre-filtration control unit and the cascade filtration control unit are bidirectionally electrically connected to the PLC controller, and the human-machine interface is bidirectionally electrically connected to the PLC controller.

[0034] The pre-filtration control unit includes a flow meter AI111, a glue supply pump AI112, and an automatic regulating valve AI113 installed on the delivery pipe I11. The flow meter AI111, glue supply pump AI112, and automatic regulating valve AI113 are located at the inlet end of the pre-filtration unit 2. Each KKF filter in the pre-filtration unit 2 is equipped with a pressure transmitter AI114 at both its inlet and outlet ends. The flow meter AI111, glue supply pump AI112, automatic regulating valve AI113, and pressure transmitter AI114 are also included. 4. Electrical signal connection with PLC controller; The cascade filter control unit includes flow meter BI121, glue supply pump BI122, pressure transmitter BI123 and automatic regulating valve BI124. Flow meter BI121, glue supply pump BI122, pressure transmitter BI123 and automatic regulating valve BI124 are installed on delivery pipe II12; Flow meter BI121, glue supply pump BI122, pressure transmitter BI123 and automatic regulating valve BI124 are electrically connected to PLC controller.

[0035] The outlet end of waste glue collection tray A21 is connected to waste glue collection tank C43 via conveying pipe IV45, and the outlet end of waste glue collection tray B32 is connected to waste glue collection tank C43 via conveying pipe V46; both conveying pipe IV45 and conveying pipe V46 are equipped with glue supply pump CI51, and the outlet end of waste glue collection tank C43 is connected to secondary filter unit 42 via conveying pipe VI47, which is equipped with glue supply pump CII471; glue supply pump CI51 and glue supply pump CII471 are electrically connected to PLC controller.

[0036] Waste glue buffer tank B33 and waste glue buffer tank C44 are connected by a conveying pipe VII34, and a glue supply pump BIII341 is installed on the conveying pipe VII34; a level transmitter I221 is installed on the upper part of waste glue buffer tanks A22, B33 and C44, and the level transmitter I221 is electrically connected to the PLC controller; a level transmitter II431 is installed on the upper part of waste glue collection tanks A1 and C43, and the level transmitter II431 is electrically connected to the PLC controller.

[0037] The flow meter AI111 and pressure transmitter AI114 are used to collect information. The flow meter AI111 can monitor the flow rate or flow of waste glue in the delivery pipe I11 and provide the flow data to the controller. It can also help operators monitor and control the production process to ensure process stability and product quality. The pre-filtration equipment uses a fully automatic online backwashing filter (KKF filter). The number of pre-filtration units 2 is arranged according to the amount of waste adhesive. Multiple KKF filters are connected in parallel in each pre-filtration unit 2. In this recycling system, the purpose is to backwash the KKF filters after they have been filtering for a period of time due to blockage and reduced flow. Backwashing usually takes 20 minutes, so multiple KKF filters and pre-filtration units 2 are set to ensure the filtration flow rate. The filtration flux of the KKF filter is 0.7 to 1.3 m³ / unit·hour. The pressure difference (ΔP) between the inlet and outlet of the KKF filter is ≤3.5 bar. The automatic regulating valve AI113 is used to regulate the inlet pressure. Backwashing is performed when the actual pressure difference is greater than the pressure difference set value. When the actual pressure difference is less than or equal to the pressure difference set value, the filtration operation continues. Therefore, it is necessary to reasonably monitor the inlet and outlet pressure and flow rate of individual KKF filters to ensure that when the flow rate decreases, some KKF filters can be automatically backwashed. The pressure transmitter AI114 is installed at the inlet and outlet of the KKF filter to monitor and measure the pressure of the fluid in the pipeline or equipment. Operators can monitor and control the production process based on the pressure data to ensure equipment safety and process stability. The flow meter AI111 can be electrically connected to the glue supply pump AI112 as an auxiliary monitoring device.

[0038] Example 5 This embodiment provides a method for waste adhesive recycling in the production of multi-sizing viscose filaments, the steps of which are as follows: a: Collection, collecting the waste adhesive generated during the production of viscose filament multi-sizing agents and temporarily storing it in a waste adhesive collection tank; The waste adhesive contained the following components: cellulose content 8.17±0.1%, alkali content 5.80±0.1%, viscosity 30–90 s, maturity 9.5–12.5 mL (10% NH4Cl), particle count >50,000 particles / mL, microscopic examination >700 particles / gram, and filtration rate <15 mL / min. The viscosity was measured using the falling ball method. b: Pre-filtration: The waste glue in the waste glue collection tank is passed into the pre-filtration unit 2. The pressure difference between the inlet and outlet of the pre-filtration unit 2 is controlled to be ≤3.5 bar to obtain pre-filtered waste glue and secondary waste glue. The precision of the KKF filter metal sintered screen in the pre-filtration unit 2 is adjusted according to the requirements to achieve high-throughput waste glue filtration within the range of 15~40um. Among them, the index parameters for controlling the waste adhesive after pre-filtration by the pre-filtration unit 2 include a particle count of 5000-6000 particles / ml, a microscopic value of 160-260 particles / gram, and a filtration rate of 65-90 ml / min; c: Step-by-step filtration: The pre-filtered waste adhesive is passed into the step-by-step filtration unit 3. The pressure difference between the inlet and outlet of the step-by-step filtration unit 3 is controlled to be ≤12 bar. The waste adhesive after being filtered by the step-by-step filtration unit 3 is obtained, which is the recycled adhesive I and the secondary waste adhesive. The step-by-step filtration unit 3 includes multiple plate and frame filters arranged in parallel with filter cloth organization. The filtration accuracy of the filter cloth organization increases step by step to meet the filtration throughput while balancing the filtration load of the filter. It is used to intercept small-diameter impurities and some elastic gel particles in the waste adhesive. The parameters for controlling the waste adhesive after filtration by the cascade filtration unit 3 include: cellulose content 8.17±0.1%, alkali content 5.80±0.1%, viscosity 30~90s (falling ball method), curing degree 9.5~12.5mL, particle number <1000 particles / mL, microscopic value ≤30 particles / gram, and filtration value ≥110ml / min; d: Reuse, the recycled adhesive I is directly fed into the degassing device in the viscose filament production system, and after degassing and pre-spinning filtration, it is spun.

[0039] The secondary waste adhesive generated by the pre-filtration unit 2 and the step-by-step filtration unit 3 is collected, and then filtered by a plate and frame filter press to obtain recycled adhesive II. The recycled adhesive II is then fed into the degassing device in the viscose filament production system.

[0040] like Figure 7 and Figure 8 As shown, in an optional embodiment, the purpose of backwashing the KKF filter during waste glue pre-filtration is to clean and restore the filtration performance of the filter screen to ensure the filtration effect and normal operation of the equipment. This involves an automatic control system for backwashing the KKF filter. The automatic control system includes a control unit and an execution unit. The control unit includes automatic differential pressure control and / or automatic timing control. Among them, the automatic differential pressure control monitors whether the actual differential pressure value at the inlet and outlet of the filter reaches the differential pressure threshold through the pressure acquisition unit. When the actual differential pressure value is greater than the set differential pressure threshold, the filter starts automatic backwashing. At this time, the execution unit controls the drain valve to open and controls the backwashing motor to start until the backwashing operation is completed. The automatic timing control uses a timing program to time the actual running time of the filter and determine whether the actual running time has reached the time threshold. When the actual running time of the filter is equal to the time threshold, the filter starts automatic backwashing. At this time, the execution unit controls the drain valve to open and controls the backwashing motor to start until the backwashing operation is completed.

[0041] Alternatively, the KKF filter can be backwashed manually. The specific steps for manual control are as follows: While the filter is operating, manually start the backwash motor, then manually open the drain valve, and finally manually start the backwash motor again to complete the backwashing process. This method effectively treats the secondary waste adhesive generated by KKF filters and plate and frame filters, protecting the environment and resources.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for recycling waste adhesive in the production of viscose filaments with multiple sizing agents, characterized in that, include: a: Collection, collecting the waste adhesive generated during the production of viscose filament multi-sizing agents and temporarily storing it in a waste adhesive collection tank; The waste adhesive contains: 8.17±0.1% methyl methacrylate, 5.80±0.1% alkali, 30-90s viscosity, 9.5-12.5mL maturity, >50,000 particles / mL, >700 fibers / gram under microscopic examination, and <15ml / min filtration rate. b: Pre-filtration, the waste glue in the waste glue collection tank is passed into the pre-filtration unit (2). The pre-filtration unit (2) is a fully automatic online backwashing KKF filter, and a metal sintered filter screen with a filtration accuracy of 15~40μm is used. The pressure difference between the inlet and outlet of the pre-filtration unit (2) is controlled to be ≤3.5bar, so as to obtain pre-filtered waste glue and secondary waste glue. Among them, the waste glue after pre-filtration by the pre-filtration unit (2) is controlled to have a particle count of 5000-6000 particles / ml, a microscopic value of 160-260 particles / gram and a filtration rate of 65-90 ml / min; c: Step-by-step filtration, the pre-filtered waste glue is passed into the step-by-step filtration unit (3), the step-by-step filtration unit (3) includes a first-stage plate and frame filter, a second-stage plate and frame filter and a third-stage plate and frame filter connected in series, wherein: the filtration accuracy of the first-stage plate and frame filter is 30-45μm; the filtration accuracy of the second-stage plate and frame filter is 15-30μm; the filtration accuracy of the third-stage plate and frame filter is 8-15μm; control the inlet and outlet of the step-by-step filtration unit (3) The pressure difference at the port is ≤12 bar. The waste glue after filtration by the step-by-step filtration unit (3) is obtained, which is the recycled glue I and the secondary waste glue. Among them, the waste glue after filtration by the step-by-step filtration unit (3) is controlled to have the following content: cellulose content 8.17±0.1%, alkali content 5.80±0.1%, viscosity 30~90s, maturity 9.5~12.5mL, particle number <1000 particles / mL, microscopic value ≤30 particles / gram, and filtration value ≥110mL / min. d: Reuse, the recycled adhesive I is directly fed into the degassing device in the viscose filament production system, and after degassing and pre-spinning filtration, it is spun; e: Secondary waste adhesive recycling: The secondary waste adhesive generated by the pre-filtration unit (2) and the step-by-step filtration unit (3) is collected, filtered by a plate and frame filter press to obtain recycled adhesive II, and the recycled adhesive II is fed into the degassing device in the viscose filament production system.

2. A waste adhesive recycling system for multi-sizing production of viscose filaments, characterized in that, The system is used to implement the waste adhesive recycling method as described in claim 1. The system includes an adhesive filtration section (5), a waste adhesive collection tank A (1), a pre-filtration unit (2), a cascade filtration unit (3), a secondary waste adhesive recycling unit (4), and a degassing section (6), forming a continuous pathway for waste adhesive generation, processing, and reuse among the units. The waste adhesive collection tank A (1) is connected to the inlet of the pre-filtration unit (2) through a conveying pipe I (11). The pre-filtration unit (2) is provided with at least two units, which are connected in parallel and are fully automatic online backwashing KKF filters with built-in metal sintered filter screens with a filtration accuracy of 15-40 μm. The pre-filtration unit (2) is connected to the inlet of the pre-filtration unit (2) through a conveying pipe II (12). The feed inlet of the cascade filtration unit (3) is connected; at least two cascade filtration units (3) are provided and connected to each other through conveying pipe III (31); each cascade filtration unit (3) includes a first-stage plate and frame filter, a second-stage plate and frame filter and a third-stage plate and frame filter connected in series, wherein the filter cloth structure of the first-stage plate and frame filter includes one layer of polypropylene and one layer of plain cloth, the filter cloth structure of the second-stage plate and frame filter includes one layer of polypropylene, one layer of double fleece, one layer of plain cloth and one layer of poplin, and the filter cloth structure of the third-stage plate and frame filter includes one layer of polypropylene, one layer of double fleece, one layer of plain cloth and two layers of poplin; the secondary waste glue recycling unit (4) includes a waste glue collection tray A (2) set at the bottom of the pre-filtration unit (2). 1) Waste glue collection tray B (32) and secondary filtration unit (42) are set at the bottom of the cascade filtration unit (3); the outlet end of the waste glue collection tray A (21) is connected to the waste glue collection tank B through the conveying pipe IV (45), and the outlet end of the waste glue collection tray B (32) is connected to the waste glue collection tank B through the conveying pipe V (46); the outlet end of the waste glue collection tank B is connected to the secondary filtration unit (42) through the conveying pipe VI (47), and the outlet of the secondary filtration unit (42) and the outlet of the cascade filtration unit (3) are connected to the degassing section (6) through the pipeline; a waste glue buffer tank A (22) is set on the conveying pipe II (12), and the waste glue collection tray A (22) is set on the conveying pipe II (12). The upper inlet of the waste glue buffer tank A (22) is connected to the pre-filtration unit (2) through the conveying pipe II (12), and the bottom outlet is connected to the cascade filtration unit (3) through the conveying pipe II (12). Each stage outlet of the cascade filtration unit (3) is connected to a waste glue buffer tank B (33). The upper inlet of the waste glue buffer tank B (33) is connected to the next stage filtration unit through a pipeline, and the bottom outlet is connected to the next stage filtration unit through a pipeline. The outlet of the secondary filtration unit (42) is connected to the waste glue buffer tank C (44) through the conveying pipe VI (47). The waste glue buffer tank B (33) and the waste glue buffer tank C (44) are connected in series to the degassing section (6).

3. A waste adhesive recycling control system in a viscose filament production system, characterized in that, The waste adhesive recycling system in the production of viscose filament multi-slurry as described in claim 2 includes a pre-filtration control unit in the pre-filtration unit (2), a cascade filtration control unit in the cascade filtration unit (3), a human-machine interface, and a PLC controller. The pre-filtration control unit and the cascade filtration control unit are bidirectionally electrically connected to the PLC controller, and the human-machine interface is bidirectionally electrically connected to the PLC controller. The pre-filtration control unit includes a flow meter AI (111), a glue supply pump AI (112), and an automatic regulating valve AI (113) installed on the conveying pipe I (11). I (113) is located at the inlet end of the pre-filtration unit (2). Each KKF filter in the pre-filtration unit (2) is equipped with a pressure transmitter AI (114) at both the inlet and outlet ends. The flow meter AI (111), glue supply pump AI (112), automatic regulating valve AI (113), and pressure transmitter AI (114) are all electrically connected to the PLC controller. The cascade filtration control unit includes a flow meter BI (121), glue supply pump BI (122), pressure transmitter BI (123), and automatic regulating valve BI (124). The waste glue collection tray A (21) at the bottom of the pre-filtration unit (2) is connected to the waste glue collection tank C (43) via the conveying pipe IV (45), and the waste glue collection tray B (32) at the bottom of the cascade filtration unit (3) is connected to the waste glue collection tank C (43) via the conveying pipe V (46); both the conveying pipe IV (45) and the conveying pipe V (46) are equipped with glue supply pump CI (51), and the outlet of the waste glue collection tank C (43) is connected to the secondary filtration unit (42) via the conveying pipe VI (47), and the conveying pipe VI (47) is equipped with glue supply pump CII (471); the glue supply pump CI (51) and glue supply pump CII (471) are electrically connected to the PLC controller; the waste glue buffer tank B (33) and waste glue buffer tank C (44) are connected through the conveying pipe VII (34), and the conveying pipe VII (34) is equipped with glue supply pump BIII (341); the waste glue buffer tank A (22), waste glue buffer tank B (33) and waste glue buffer tank C (44) are all equipped with level transmitter I (221), and the level transmitter I is electrically connected to the PLC controller; the waste glue collection tank A (1) and waste glue collection tank C (43) are all equipped with level transmitter II (431), and the level transmitter II (431) is electrically connected to the PLC controller.

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