Waste paper papermaking method for improving cyclic utilization rate of white water

Abstract

The invention discloses a waste paper papermaking method capable of improving the cyclic utilization rate of white water, and relates to the technical field of waste paper papermaking. The tailings treated by the clarifier are recycled and used for preparing white water; in a papermaking workshop, white water is recycled through an off-machine white water tank; in a pulping workshop, a multi-disc fiber recycling machine is adopted for grading redundant white water in the workshop; the ultra-clear white water is filtered by a super-filter and then is used for a net part low-pressure spraying system and a pressing part low-pressure spraying system of a papermaking workshop; reusing the turbid white water into a pulper for pulping so as to recover fibers in the white water; and in a wastewater workshop, the wastewater subjected to anaerobic and aerobic treatment is treated by an ultrafiltration membrane and a reverse osmosis membrane. And through a four-stage recycling technology, the cyclic utilization rate of the white water in the waste paper papermaking workshop is increased to 97% or above.

Description

Technical Field

[0001] The invention relates to the technical field of waste paper papermaking, and in particular to a waste paper papermaking method capable of improving the recycling rate of white water. Background Art

[0002] In the field of waste paper papermaking technology, a large amount of wastewater is generated during the papermaking process. These wastewaters contain a large amount of fine fibers. If they are directly discharged into the environment, they will not only cause environmental pollution, but also waste a lot of resources. Therefore, how to effectively recycle and utilize the fine fibers in these wastewaters to reduce environmental pollution and waste of resources is an important issue facing the current waste paper papermaking technology. In the field of water resource recycling technology, wastewater treatment and reuse in paper mills is an important link.

[0003] Traditional wastewater treatment schemes mainly treat wastewater through physical, chemical and biological methods, and then discharge or reuse it. For example, in the pulping workshop, a high-efficiency shallow flotation clarifier is used to treat the tailings of the lightweight desander and reuse the white water. The papermaking workshop uses an external white water tank to recycle white water. This method can effectively recover and utilize the fine fibers in the papermaking wastewater, reducing environmental pollution and waste of resources. However, there are still some problems in the practical application of the existing waste paper papermaking technology. First, the existing wastewater treatment methods often require a lot of energy and chemicals, and the operating cost is high. Secondly, the existing wastewater treatment methods have limited treatment effects, cannot effectively recover and utilize the fine fibers in the wastewater, and cause waste of resources. Finally, the existing wastewater treatment methods are complex in equipment, inconvenient to operate, and have high operating costs, which are not conducive to widespread promotion and application in the papermaking industry. Therefore, this paper proposes a waste paper papermaking method that improves the recycling rate of white water to solve the above problems. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a waste paper papermaking method for improving the recycling rate of white water.

[0005] Use high-efficiency shallow air flotation clarifier to treat the tailings of light desander;

[0006] The tailings after treatment in the clarifier are recycled to prepare white water;

[0007] In the papermaking workshop, an external white water tank is used to recycle white water; this method can effectively recycle and utilize the fine fibers in the papermaking wastewater, reducing environmental pollution and waste of resources.

[0008] In the pulping workshop, a multi-disc fiber recovery machine is used to classify the excess white water in the workshop;

[0009] The ultra-clear white water is filtered through a super filter and used in the low-pressure spraying system of the wire and press parts of the papermaking workshop;

[0010] The turbid white water is returned to the pulper for pulping to recover the fibers in the white water and reduce loss. This method can improve the recycling rate of wastewater and reduce the production cost of the enterprise.

[0011] In the wastewater workshop, the wastewater that has undergone anaerobic and aerobic treatment is then treated by ultrafiltration membranes and reverse osmosis membranes. The good water returns to the workshop's clean water system and is used in the workshop's cooling water system, sealing water system, and high-pressure spray system. The high-salt water is discharged into the wastewater network. This method can further improve the recycling rate of wastewater and reduce the company's production costs.

[0012] Furthermore, when the flotation clarifier treats the tailings of the light desander, the tailings are placed in the clarifier, the working parameters of the clarifier are adjusted, flocculants are added, and compressed air is introduced. The temperature is set to 25°C, the pressure is set to 1.0MPa, and the time is 30 minutes to ensure that the tailings are fully treated. The treated tailings will be sent to the next step of treatment.

[0013] Furthermore, when the tailings are recycled and used to prepare white water, the tailings are mixed with water, and the mixing ratio is adjusted so that the concentration is ≤2.5% to ensure the quality of the white water. Then, compressed air is mixed in to make the impurities attached to the bubbles and float to the surface. The impurities are removed by the skimmer on the high-efficiency shallow flotation clarifier, and the treated white water overflows the high-efficiency shallow flotation clarifier.

[0014] Furthermore, when the white water tank outside the machine recycles white water, the white water tank outside the machine collects and holds the white water taken off by the paper machine mesh, and the bottom is connected to the pulp pump, and the white water in the white water tank outside the machine is used to dilute the pulp to meet the concentration requirements of the pulp on the net. The parameters of the white water tank are set to: temperature of 20℃, pressure of 0.8MPa, and time of 2 hours to ensure the full recovery of white water, and the recovered white water will be sent to the next step of processing.

[0015] Furthermore, when the multi-disc fiber recovery machine is classifying white water, the multi-disc fiber recovery machine is equipped with a distribution valve to filter out ultra-clear white water, clear white water, and turbid white water. The working parameters of the multi-disc fiber recovery machine are set to: the speed is 1000rpm and the time is 1 hour to ensure that the white water is fully classified. The classified white water will be sent to the next step of treatment.

[0016] Furthermore, when the ultra-clear white water is filtered through the super filter, the working parameters of the super filter are set to: the filter mesh number is 80-150 mesh, the temperature is 25°C, the pressure is 0.9MPa, and the time is 1.5 hours to ensure sufficient filtration of the ultra-clear white water. The filtered ultra-clear white water will be sent to the corresponding section of the papermaking workshop.

[0017] Furthermore, when pulping with a pulper, turbid white water is added to dilute the pulp concentration to 4%-6%.

[0018] Furthermore, when the wastewater is treated anaerobically and aerobically, the working parameters of the anaerobic treatment are set to: temperature 36-39°C, rising speed 4-8 m / s. The working parameters of the aerobic treatment are set to: residence time ≥ 8 hours; dissolved oxygen content of water is 2-5 mg / L. The working parameters of the ultrafiltration membrane treatment are set to: temperature 20°C, pressure 0.8MPa, pressure difference between inlet and outlet water ≤ 0.2MPa, turbidity of produced water < 1NTU, time 1 hour; the working parameters of the reverse osmosis membrane treatment are set to: inlet water pressure 0.8-1.2MPa, temperature 30-40°C, pressure difference between inlet and outlet water ≤ 0.3MPa, conductivity of outlet water ≤ 500μs / cm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) This papermaking method improves the recycling rate of white water: Through the four-level reuse technology, the recycling rate of white water in the waste paper papermaking workshop can be increased to more than 97%, greatly reducing the discharge of wastewater and reducing pollution to the environment.

[0021] (2) This papermaking method saves water resources: by increasing the recycling rate of white water, the clean water consumption per ton of paper is reduced to less than 3 tons. Compared with the traditional papermaking process, it greatly saves water resources and realizes the sustainable use of water resources.

[0022] (3) This papermaking method reduces fiber loss: By analyzing and studying the water demand and drainage characteristics of each section of the waste paper pulping and papermaking workshop, a reasonable white water reuse plan is formulated, which can effectively reduce the loss of fine fibers contained in the white water and improve resource utilization.

[0023] (4) This papermaking method reduces production costs: By implementing the four-level white water reuse technology, it can not only reduce wastewater discharge and reduce environmental pressure, but also reduce the use of new water, reduce production costs, and improve the economic benefits of the enterprise.

[0024] (5) The papermaking method simplifies the processing flow: The four-stage white water recycling technology adopted in this technical solution has simple equipment, convenient operation, and low operating cost, which is conducive to its wide promotion and application in the papermaking industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is an overall flow chart. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0027] Embodiment 1, the present invention is a waste paper papermaking method for improving the recycling rate of white water. In the pulping workshop, a high-efficiency shallow flotation clarifier is used to treat the tailings of the light desander. In the process of the flotation clarifier treating the tailings of the light desander, the tailings are placed in the clarifier, the working parameters of the clarifier are adjusted, flocculants are added, and compressed air is introduced. The temperature is set to 25°C, the pressure is set to 1.0MPa, and the time is 30 minutes to ensure that the tailings are fully treated. The treated tailings will be sent to the next step of treatment.

[0028] The tailings treated by the clarifier are reused to prepare white water. In the process of recycling the tailings and using them to prepare white water, the tailings are mixed with an appropriate amount of water, and the mixing ratio is adjusted to make the concentration ≤2.5% to ensure the quality of the white water. Then, compressed air is mixed in to make the impurities attached to the bubbles and float to the surface. The impurities are removed by the skimmer on the high-efficiency shallow air flotation clarifier, and the treated white water overflows the high-efficiency shallow air flotation clarifier.

[0029] In the papermaking workshop, white water is recycled by using an external white water tank. In the process of recycling white water, the external white water tank collects and holds the white water taken off by the paper machine mesh. The bottom is connected to a pulp pump, and the white water in the external white water tank is used to dilute the pulp to meet the concentration requirements of the pulp on the mesh. The parameters of the white water tank are set to: temperature of 20°C, pressure of 0.8MPa, and time of 2 hours to ensure full recycling of white water. The recycled white water will be sent to the next step of treatment. This method can effectively recycle and utilize fine fibers in papermaking wastewater, reducing environmental pollution and waste of resources.

[0030] In the pulping workshop, a multi-disc fiber recovery machine is used to classify the excess white water in the workshop. During the classification of white water by the multi-disc fiber recovery machine, the multi-disc fiber recovery machine is equipped with a distribution valve to filter out ultra-clear white water, clear white water, and turbid white water. The working parameters of the multi-disc fiber recovery machine are set to: speed of 1000rpm, time of 1 hour to ensure full classification of white water. The classified white water will be sent to the next step of treatment.

[0031] The ultra-clear water is filtered through the super filter and used in the low-pressure spray system of the screen and pressure section of the papermaking workshop. During the filtering process of the ultra-clear water through the super filter, the working parameters of the super filter are set as follows: the filter mesh number is 80-150 mesh, the temperature is 25℃, the pressure is 0.9MPa, and the time is 1.5 hours to ensure that the ultra-clear water is fully filtered. The filtered ultra-clear water will be sent to the corresponding section of the papermaking workshop.

[0032] When using a pulper to pulp, add turbid white water to dilute the pulp concentration to 4%-6%. During the pulping process of the crusher with turbid white water, the working parameters of the pulper are set to: speed of 800rpm, time of 2 hours, to ensure that the fibers in the white water are fully recovered. This method can improve the recycling rate of wastewater and reduce the production cost of the enterprise.

[0033] In the wastewater workshop, the wastewater treated by anaerobic and aerobic treatment is then treated by ultrafiltration membrane and reverse osmosis membrane. During the anaerobic and aerobic treatment of the wastewater, the working parameters of the anaerobic treatment are set to: temperature of 36-39℃, rising speed of 4-8 m / s. The working parameters of the aerobic treatment are set to: pressure of 0.9MPa, residence time ≥8 hours; dissolved oxygen content of water is 2-5mg / L. The working parameters of the ultrafiltration membrane treatment are set to: pressure difference of inlet and outlet water ≤0.2MPa, turbidity of produced water <1NTU; the working parameters of the reverse osmosis membrane treatment are set to: inlet water pressure of 0.8-1.2MPa, temperature of 30-40℃, pressure difference of inlet and outlet water ≤0.3MPa, conductivity of outlet water ≤500μs / cm. The treated good water will be sent to the clean water system of the workshop and used in the workshop cooling water system, sealing water system and high-pressure spraying system. The high-salt water is discharged into the wastewater network. This method can further improve the recycling rate of wastewater and reduce enterprise production costs.

[0034] Through the above working process, the recycling rate of white water in the waste paper papermaking workshop can be effectively improved, the production cost of the enterprise can be reduced, and at the same time, the wastewater treatment and recycling equipment can be simplified and the operating cost can be reduced.

[0035] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention are implemented according to the conventional means in the field without special explanation and limitation.

Claims

1. A method for making paper from waste paper with improved recycling rate of white water, characterized in that: Use high-efficiency shallow air flotation clarifier to treat the tailings of light desander; The tailings after treatment in the clarifier are recycled to prepare white water; In the papermaking workshop, white water is recovered by using an off-machine white water tank; In the pulping workshop, a multi-disc fiber recovery machine is used to classify the excess white water in the workshop; The ultra-clear white water is filtered through a super filter and used in the low-pressure spraying system of the wire and press parts of the papermaking workshop; The turbid white water is returned to the pulper for pulping to recover the fibers in the white water; In the wastewater workshop, the wastewater that has undergone anaerobic and aerobic treatment is then treated by ultrafiltration membrane and reverse osmosis membrane. The treated good water will be sent to the workshop's clean water system and used in the workshop's cooling water system, sealing water system, and high-pressure spraying system. The high-salt water will be discharged into the wastewater network.

2. The method for making paper from waste paper with improved recycling rate of white water according to claim 1, characterized in that: When the flotation clarifier treats the tailings of the light desander, the tailings are placed in the clarifier, the working parameters of the clarifier are adjusted, flocculants are added, and compressed air is introduced.

3. The method for making paper from waste paper with improved recycling rate of white water according to claim 1, characterized in that: When the tailings are recycled and used to prepare white water, the tailings are mixed with water, and the mixing ratio is adjusted to make its concentration ≤2.5%. Then, compressed air is mixed in to make the impurities attach to the bubbles and float to the surface. The impurities are removed by the skimmer on the high-efficiency shallow air flotation clarifier, and the treated white water overflows the high-efficiency shallow air flotation clarifier.

4. The method for making paper from waste paper with improved recycling rate of white water according to claim 1, characterized in that: When the external white water tank recycles white water, it collects and holds the white water taken off from the paper machine mesh. The bottom is connected to a pulp flushing pump to dilute the pulp to meet the concentration requirements of the pulp before it goes online.

5. The method for making paper from waste paper with improved recycling rate of white water according to claim 1, characterized in that: When the multi-disc fiber recovery machine classifies white water, the multi-disc fiber recovery machine is equipped with a distribution valve to filter out ultra-clear white water, clear white water and turbid white water.

6. The method for making paper from waste paper with improved recycling rate of white water according to claim 1, characterized in that: When the ultra-clear water is filtered through the super filter, the working parameters of the super filter are set to: the filter mesh number is 80-150 meshes.

7. The method for making paper from waste paper with improved recycling rate of white water according to claim 1, characterized in that: When using a pulper to pulp, add turbid white water to dilute the pulp concentration to 4%-6%.

8. The method for making paper from waste paper with improved recycling rate of white water according to claim 1, characterized in that: When the wastewater is treated anaerobically and aerobically, the working parameters of the anaerobic treatment are set as follows: the temperature is 36-39°C and the rising speed is 4-8 m / s. The working parameters of aerobic treatment are set as follows: residence time ≥ 8 hours; dissolved oxygen content of water is 2-5 mg / L. The working parameters of the ultrafiltration membrane treatment are set as follows: the pressure difference between the inlet and outlet water is ≤0.2MPa, and the turbidity of the produced water is <1NTU. The working parameters of the reverse osmosis membrane treatment are set as follows: water inlet pressure 0.8-1.2MPa, temperature 30-40°C, pressure difference between inlet and outlet water ≤0.3MPa, and conductivity of outlet water ≤500μs / cm.

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