Tissue paper whitewater treatment system

Abstract

This utility model belongs to the field of papermaking technology and discloses a white water treatment system for household paper products. It includes an under-machine white water tank, a white water sluice, a white water tower, a white water collection tank, and a primary disc filter. The outlet of the under-machine white water tank is directly connected to the inlet of the primary disc filter via a conveying pipeline. The outlet of the white water tower is connected to the under-machine white water tank via a first connecting pipeline. The outlet of the white water sluice is connected to the under-machine white water tank via a second connecting pipeline. Furthermore, the outlet of the white water collection tank is connected to the under-machine white water tank via a third connecting pipeline. Compared with existing technologies, this utility model enables all white water to be treated by the primary disc filter, maximizing fiber recovery, avoiding secondary handling of white water, and saving energy.

Description

Technical Field

[0001] This utility model relates to the field of papermaking technology, and in particular to a white water treatment system for household paper. Background Technology

[0002] In the production of household paper, the recycling of white water (wastewater generated during papermaking) is crucial for system cleanliness, fiber recovery, and cost control.

[0003] Traditional white water treatment systems typically employ a white water tower-centric architecture. The basic process involves pumping white water from the machine to the white water tower, which then pumps it to a Primary Disc Filter (PDF) for further treatment before distributing it to various points of use. However, this traditional white water treatment system has several significant drawbacks: First, not all white water undergoes PDF treatment, and the high concentration of white water leads to severe deterioration of the water quality within the white water tower over long-term operation. High-concentration white water tends to accumulate at the bottom of the white water tower, and since the white water used in the pulping and thickening processes is drawn from the bottom, excessive fine fibers are carried into the pulping system, affecting paper quality and increasing chemical consumption. Second, white water towers are usually designed with large volumes (e.g., 350 m³), ​​resulting in slow white water circulation within the system. Fibers easily settle and accumulate, causing fiber loss with discharged wastewater and reducing pulp utilization. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a white water treatment system for household paper that can achieve full white water treatment, efficient fiber recovery, and stable system operation.

[0005] The technical solution of this utility model is:

[0006] This utility model provides a white water treatment system for household paper products, including an under-machine white water tank, a white water sluice, a white water tower, a white water collection tank, and a primary disc filter. The outlet of the under-machine white water tank is directly connected to the inlet of the primary disc filter through a conveying pipeline; the outlet of the white water tower is connected to the under-machine white water tank through a first connecting pipeline; the outlet of the white water sluice is connected to the under-machine white water tank through a second connecting pipeline; and the outlet of the white water collection tank is connected to the under-machine white water tank through a third connecting pipeline.

[0007] Optionally, a first control valve is provided on the first connecting pipeline, and the household paper white water treatment system is configured to automatically control the liquid level of the white water tank below the machine by adjusting the opening of the first control valve.

[0008] Optionally, it also includes an automatic control unit and a liquid level detection unit disposed in the white water tank under the machine. The automatic control unit is communicatively connected to the liquid level detection unit and the first control valve, and is configured to increase the opening of the first control valve when the liquid level in the white water tank under the machine decreases, and decrease the opening of the first control valve when the liquid level rises.

[0009] Optionally, the white water tank below the machine is positioned vertically lower than the white water tower.

[0010] Optionally, an overflow plate is provided in the white water chute, which divides the white water chute into an overflow area and a circulation area; a first drain valve is provided on the side wall or bottom of the overflow area, and a second drain valve is provided at the bottom of the circulation area. Both the first drain valve and the second drain valve are connected to the white water chute under the machine through the second connecting pipe.

[0011] Optionally, the white water tower is connected to the circulation zone of the white water sluice through a concentration regulating pipeline. The concentration regulating pipeline is equipped with a second control valve. The household paper white water treatment system is configured to automatically control the concentration of the white water sluice by adjusting the opening of the second control valve.

[0012] Optionally, the household paper white water treatment system is further provided with an emergency return pipeline. The inlet end of the emergency return pipeline is connected to the white water tank under the machine, and the outlet end is connected to the white water tower. An emergency control valve is provided on the emergency return pipeline.

[0013] Optionally, the white water chute, the headbox of the paper machine, and the forming section together form a short circulation loop: the outlet of the white water chute is connected to the headbox through a short circulation pipeline for conveying a mixture of white water and pulp; the forming section is located after the headbox for dewatering and forming the pulp, and directly returning the dewatered white water to the white water chute.

[0014] Optionally, the outlet of the white water tower is also used to supply white water to the slurry dispersing system and the thickening system, and the slurry output from the slurry dispersing system and the thickening system is transported to the short circulation pipeline.

[0015] Optionally, the primary disc filter is provided with multiple water outlets, which are respectively connected to the turbid white water tank, the clear white water tank and the ultra-clear white water tank; and the clear white water tank is connected to the white water tower through a return pipe.

[0016] Compared with the prior art, the white water treatment system for household paper of this utility model has the following significant advantages:

[0017] This utility model's tissue paper white water treatment system connects the outlets of the white water tower, white water chute, and white water collection tank to the under-machine white water tank via corresponding pipelines. The outlet of the under-machine white water tank is then directly connected to the inlet of the primary disc filter (PDF) via a conveying pipeline. This allows all white water from the tissue paper white water treatment system (including collected wastewater below the paper machine, overflow or makeup water from the white water tower, and overflow and circulating water from the white water chute) to the primary disc filter for unified fiber recovery treatment. This achieves complete collection, treatment, and reuse of white water during production, maximizing fiber recovery, reducing pulp waste and chemical consumption, and saving energy consumption from secondary white water pumping by simplifying and optimizing the process. This also enables automatic balancing and stable operation of the tissue paper white water treatment system. Furthermore, since all white water is treated by the primary disc filter, fine fibers and impurities are effectively removed, preventing water quality deterioration caused by high-concentration white water accumulating at the bottom of the white water tower. Attached Figure Description

[0018] Figure 1 This is a flowchart of the household paper white water treatment system of this utility model.

[0019] Explanation of reference numerals in the attached figures:

[0020] White water treatment system 100, under-machine white water tank 1, white water chute 2, overflow plate 21, overflow area 22, circulation area 23, first drain valve 24, second drain valve 25, white water tower 3, white water collection tank 4, primary disc filter 5, turbid white water tank 51, clear white water tank 52, ultra-clear white water tank 53, conveying pipeline 6, first connecting pipeline 7, first control valve 71, second connecting pipeline 8, third connecting pipeline 9, concentration adjustment pipeline 10, second control valve 101, return pipeline 11, short circulation pipeline 12, first circulation pipeline 121, second circulation pipeline 122, emergency return pipeline 13, emergency control valve 131, head box 14. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] For ease of interpretation and precise definition in the claims, the terms "upper," "lower," "inner," "outer," "left," and "right," as well as "front" and "rear," are used to describe these features with reference to their positions in the exemplary embodiments shown in the figures. Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0023] Please see Figure 1 As shown, this utility model provides a white water treatment system 100 for household paper products, including an under-machine white water tank 1, a white water chute 2, a white water tower 3, a white water collection tank 4, and a primary disc filter 5. These components are connected by specific pipelines to form a highly efficient and closed white water circulation system, thereby solving the problems of incomplete white water treatment, water quality deterioration, and high energy consumption in traditional systems.

[0024] The under-machine white water tank 1 is a barrel-shaped structure, generally located underground, preferably at a depth of -5 to -6 meters. The under-machine white water tank 1 is the collection center and balancing hub of the household paper white water treatment system 100. It is mainly used to collect all white water and serve as the direct inlet of the primary disc filter 5, thereby avoiding the use of the white water tower 3 for secondary handling and saving energy consumption.

[0025] Furthermore, the white water flowing into the white water tank 1 below the machine mainly comes from three sources: the white water tower 3, the white water chute 2, and the white water collection tank 4. The outlet of the white water tower 3 is connected to the white water tank 1 below the machine via a first connecting pipe 7. The outlet of the white water chute 2 is connected to the white water tank 1 below the machine via a second connecting pipe 8. And the outlet of the white water collection tank 4 is connected to the white water tank 1 below the machine via a third connecting pipe 9. This arrangement ensures that all the white water in the white water treatment system 100 is collected in the white water tank 1 below the machine, allowing all the white water to be processed in the primary disc filter 5 after flowing through the white water tank 1 below the machine.

[0026] Preferably, the concentration of white water in the white water tank 1 below the machine is about 0.04%.

[0027] The outlet of the under-machine white water tank 1 is directly connected to the inlet of the primary disc filter 5 via the delivery pipeline 6. This configuration ensures that all collected under-machine white water can be delivered to the primary disc filter 5 for fiber recovery, maximizing fiber recovery from the source and avoiding water quality deterioration and secondary pumping energy consumption problems caused by the white water tower 3 acting as an intermediate link in traditional systems.

[0028] Furthermore, a liquid level detection unit (not shown), such as a liquid level gauge, is installed on the white water tank 1 below the machine to detect the liquid level in the white water tank 1 below the machine, thereby avoiding the overflow or evacuation of the white water tank 1 below the machine and achieving the balance of the white water treatment system 100.

[0029] Furthermore, the white water treatment system 100 also includes an automatic control unit (not shown). This automatic control unit is communicatively connected to the liquid level detection unit and the first control valve 71 on the first connecting pipe 7, and is configured to automatically open the first control valve 71 to increase the water supply from the white water tower 3 when the liquid level in the lower white water tank 1 decreases; and automatically close the first control valve 71 to reduce the water supply when the liquid level rises. This configuration effectively adapts to liquid level fluctuations caused by changes in the treatment capacity of the primary disc filter 5 and changes in the inflow of water into the white water sluice 2, achieving automatic water balance for the entire white water treatment system 100.

[0030] Furthermore, the location of the water tank 1 below the machine is lower in the vertical direction than the location of the water tower 3. This allows the water supply to be made by gravity using the height difference between the two, reducing the need for a pump and making it more energy-efficient and reliable. Preferably, the water tank 1 below the machine is located at the -5.6-meter level, while the water tower 3 and other structures are located at the 0-meter level.

[0031] The primary disc filter 5 (PDF), typically installed on the ground, primarily handles fiber recovery and classification of white water. The primary disc filter 5 has multiple outlets connected to a turbid white water tank 51, a clear white water tank 52, and an ultra-clear white water tank 53, respectively. The clear white water tank 52 is connected to the white water tower via a return pipe. In other words, the primary disc filter 5, through graded treatment, outputs three types of water: turbid white water, clear white water, and ultra-clear white water, which are stored in their respective tanks 51, 52, and 53. The turbid white water, with the highest concentration, serves as the internal circulating water and internal spray water for the primary disc filter 5. The clear and ultra-clear white water are supplied to the paper machine spray system, which has higher water quality requirements, and then return to the white water collection tank 4 through pressing and vacuum processes. Excess clear white water is returned to the white water tower 3 via the return pipe 11, thus achieving graded and tiered utilization of water quality.

[0032] White water tower 3, as an auxiliary balancing and water replenishment component in white water treatment system 100, differs from the role of the core storage unit in the prior art. By optimizing its structural design and working in coordination with other components in white water treatment system 100, it achieves efficient circulation of white water.

[0033] Specifically, the white water tower 3 is connected to the white water tank 1 below the machine via the first connecting pipe 7. Its main function is to provide makeup water to the white water treatment system 100 to maintain the balance of white water. When the liquid level in the white water tank 1 below the machine decreases (for example, due to an increase in the processing capacity of the primary disc filter 5 or fluctuations in the amount of white water produced), the automatic control unit (not shown) adjusts the opening of the first control valve 71 to increase the makeup water supply to the white water tower 3; conversely, when the liquid level rises, the makeup water supply to the white water tower 3 is reduced. This dynamic adjustment ensures the stability of the operation of the white water treatment system 100 and avoids overflow or cavitation problems.

[0034] Furthermore, the white water tower 3 primarily receives excess white water returned from the white water tank 52. This water is clean, maintaining the white water tower 3 itself at a low concentration (0.02%–0.03%). This not only avoids the problem of high-concentration white water accumulating at the bottom of the white water tower 3 in traditional systems, but also provides a high-quality water source for diluting the pulp in the pulping and thickening systems, forming a closed-loop optimization of water quality. Moreover, because the water source used in the pulping and thickening systems is clean, the reintroduction of large amounts of fine fibers and contaminants into the pulping system is prevented from the source, thereby reducing chemical consumption and improving paper quality.

[0035] An overflow plate 21 is installed inside the white water chute 2. The overflow plate 21 divides the white water chute 2 into an overflow zone 22 and a circulation zone 23. A first drain valve 24 is installed on the side wall or bottom of the overflow zone 21, mainly used to discharge surface foam and scum. A second drain valve 25 is installed at the bottom of the circulation zone 23. Both the first drain valve 24 and the second drain valve 25 are connected to the white water tank 1 below the machine via a second connecting pipe 8. This configuration allows for the forced discharge of water stored at the bottom of the circulation zone 23 by adjusting the opening of the second drain valve 25, accelerating the flow and renewal of white water, thus solving the problems of sludge accumulation and water quality deterioration at the bottom of traditional chutes, and improving water quality without the need for external discharge of clean water.

[0036] Furthermore, the white water chute 2, the headbox 14 of the paper machine, and the forming section together form a short circulation loop via the circulation pipe 12: the outlet of the white water chute 2 is connected to the headbox 14 via the first short circulation pipe 121, for supplying a mixture of white water and pulp to the headbox 14. The forming section, located after the headbox 14, is used to dewater and form the pulp, and the dewatered white water is directly returned to the white water chute 2 via the second circulation pipe 122. Furthermore, the outlet of the white water tower 3 is also used to supply white water to the pulping system and the thickening system, and the pulp output from the pulping system and the thickening system is transported to the short circulation pipe 12. This arrangement ensures that the entire process from pulping to forming is carried out in high-quality water, reducing the fine fiber content of the pulp by 15%, reducing chemical consumption by 20%, and significantly improving paper uniformity.

[0037] Furthermore, the white water tower 3 is connected to the circulation zone 23 of the white water sluice 2 via a concentration regulating pipe 10. A second control valve 101 is installed on the concentration regulating pipe 10, and the household paper white water treatment system 100 is configured to automatically control the concentration of the white water sluice 2 by adjusting the opening of the second control valve 101. For example, the operator can adjust the second control valve 101 through the automatic control unit to replenish the white water sluice 2 with low-concentration white water, thereby precisely controlling the white water concentration of the short circulation system within an optimized range of 0.05% to 0.06%.

[0038] White water collection tank 4 is used to collect wastewater from other parts of the paper machine (such as the press section). It is connected to the white water tank 1 under the machine through the third connecting pipe 9 to ensure that no white water is leaked.

[0039] Furthermore, the household paper white water treatment system 100 is also equipped with an emergency return pipeline 13. The inlet end of the emergency return pipeline 13 is connected to the white water tank 1 below the machine, and its outlet end is connected to the white water tower 3. An emergency control valve 131 is installed on the emergency return pipeline 13. The emergency return pipeline 13 is normally closed. When the primary disc filter 5 unexpectedly stops, causing the liquid level in the white water tank 1 below the machine to rise sharply, the emergency control valve 131 can be opened manually or automatically to urgently divert the white water in the white water tank 1 below the machine to the larger capacity white water tower 3 for temporary storage, preventing the white water tank 1 below the machine from overflowing and ensuring system safety.

[0040] The overall process of the household paper white water treatment system 100 of this utility model is as follows: During the production process of household paper, white water is collected from the white water collection tank 4 below the paper machine, the overflow area 22 and circulation area 23 of the white water chute 2, and the makeup water of the white water tower 3, and finally all flows into the underground white water tank 1. The underground white water tank 1 directly pumps all the white water to the primary disc filter 5 through the conveying pipeline 6. The primary disc filter 5 performs core classification and recycling treatment on the white water, and the treated white water is classified and stored in corresponding bins to supply different water points, forming a closed loop. This process simplifies the traditional multi-stage pumping, significantly reduces energy consumption, and lays the structural foundation for the automatic control of the system.

[0041] In addition, the white water tank 1, white water chute 2, white water tower 3, turbid white water tank 51, clear white water tank 52 and ultra-clear white water tank 53 under the machine are all equipped with liquid level detection units. These liquid level detection units are connected to the automatic control unit to realize automatic control of the liquid level.

[0042] Specifically, during normal production, the flow rate of white water from the machine's underpass to the primary disc filter 5 will change, as will the water supply to the white water sluice 2. Both of these changes can be stabilized by the first control valve 71 on the first connecting pipe 7. When the water level in the underpass white water sluice 1 decreases, the opening of the first control valve 71 is automatically increased, increasing the water supply from the white water tower 3; when the water level rises, the opening is automatically decreased. This closed-loop control automatically compensates for level changes caused by variations in the processing capacity of the primary disc filter 5 or fluctuations in the water flow to the white water sluice 2, thereby automatically and accurately maintaining the water balance of the entire system, effectively preventing overflow and cavitation, and ensuring absolute operational stability.

[0043] In summary, this utility model constructs a white water treatment system 100 integrating high-efficiency recycling, energy saving and consumption reduction, automatic stability, and safety and reliability through the layering and organic synergy of the above-mentioned components. By connecting the outlets of the white water tower 3, white water chute 2, and white water collection tank 4 to the white water tank 1 under the machine through corresponding pipelines, and directly connecting the outlet of the white water tank 2 to the inlet of the primary disc filter 5 through the conveying pipeline 6, all white water in the tissue paper white water treatment system 100 (including the collected wastewater under the paper machine, the overflow or makeup water of the white water tower 3, and the overflow and circulating water of the white water chute 2) is transported to the primary disc filter 5 for unified fiber recycling treatment, realizing the full collection, full treatment, and full reuse of white water in the production process. This not only maximizes fiber recovery and reduces pulp waste and chemical consumption, but also saves energy consumption for secondary pumping of white water by simplifying and optimizing the process, thereby achieving automatic balance and stable operation of the tissue paper white water treatment system 100. In addition, since all the white water is treated by the primary disc filter 5, fine fibers and impurities are effectively removed, thus avoiding the water quality deterioration problem caused by the accumulation of high-concentration white water at the bottom of the white water tower 3.

Claims

1. A system for treating white water for tissue paper, characterized in that The system includes an under-machine white water tank, a white water sluice, a white water tower, a white water collection tank, and a primary disc filter. The outlet of the under-machine white water tank is directly connected to the inlet of the primary disc filter via a delivery pipeline. The outlet of the white water tower is connected to the under-machine white water tank via a first connecting pipeline. The outlet of the white water sluice is connected to the under-machine white water tank via a second connecting pipeline. Furthermore, the outlet of the white water collection tank is connected to the under-machine white water tank via a third connecting pipeline.

2. The household paper white water treatment system according to claim 1, characterized in that, A first control valve is provided on the first connecting pipeline, and the household paper white water treatment system is configured to automatically control the liquid level of the white water tank under the machine by adjusting the opening of the first control valve.

3. The household paper white water treatment system according to claim 2, characterized in that, It also includes an automatic control unit and a liquid level detection unit disposed in the white water tank under the machine. The automatic control unit is communicatively connected to the liquid level detection unit and the first control valve, and is configured to increase the opening of the first control valve when the liquid level in the white water tank under the machine decreases, and decrease the opening of the first control valve when the liquid level increases.

4. The household paper white water treatment system according to claim 1, characterized in that, The location of the white water tank below the machine is lower than the location of the white water tower in the vertical direction.

5. The household paper white water treatment system according to claim 1, characterized in that, An overflow plate is provided inside the white water chute, which divides the white water chute into an overflow area and a circulation area; a first drain valve is provided on the side wall or bottom of the overflow area, and a second drain valve is provided at the bottom of the circulation area. Both the first drain valve and the second drain valve are connected to the white water chute under the machine through the second connecting pipe.

6. The household paper white water treatment system according to claim 5, characterized in that, The white water tower is connected to the circulation zone of the white water sluice through a concentration regulating pipeline. A second control valve is provided on the concentration regulating pipeline. The household paper white water treatment system is configured to automatically control the concentration of the white water sluice by adjusting the opening of the second control valve.

7. The household paper white water treatment system according to claim 1, characterized in that, The household paper white water treatment system is also equipped with an emergency return pipeline. The inlet end of the emergency return pipeline is connected to the white water tank under the machine, and the outlet end is connected to the white water tower. An emergency control valve is also provided on the emergency return pipeline.

8. The household paper white water treatment system according to claim 1, characterized in that, The white water chute, the headbox of the paper machine, and the forming section together form a short circulation loop: the outlet of the white water chute is connected to the headbox through a short circulation pipeline for conveying a mixture of white water and pulp; the forming section is located after the headbox for dewatering and forming the pulp, and directly returning the dewatered white water to the white water chute.

9. The household paper white water treatment system according to claim 8, characterized in that, The outlet of the white water tower is also used to supply white water to the slurry dispersing system and the thickening system, and the slurry output from the slurry dispersing system and the thickening system is transported to the short circulation pipeline.

10. The household paper white water treatment system according to claim 1, characterized in that, The primary disc filter has multiple outlets, which are respectively connected to the turbid white water tank, the clear white water tank, and the ultra-clear white water tank; and the clear white water tank is connected to the white water tower through a return pipe.

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