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CN-122013586-A - High-frequency fluffing-air floatation cooperative waste paper fine screening slag complete recycling system and method

CN122013586ACN 122013586 ACN122013586 ACN 122013586ACN-122013586-A

Abstract

The invention discloses a high-frequency fluffing-air floatation synergistic waste paper fine screening residue complete recycling system and method, and belongs to the technical field of waste paper pulping and solid waste recycling. The system realizes the complete recycling of fine screening slag through a high-frequency fluffing unit, an air flotation separation unit, a fiber recovery unit and a slag discharging energy unit which are sequentially connected in a closed loop. The method comprises the steps of conducting high-frequency fluffing on the fine screening slag slurry under a specific low concentration (0.5% -1.1%), controlling the slag discharging rate (10% -20%) of the air flotation separation unit, separating clean slurry and high-heat-value scum, concentrating the clean slurry for recycling, and converting the scum into biomass solid fuel with heat value not lower than 20MJ/kg or pyrolysis gas production after dehydration. The invention forms a complete industrial closed loop from waste residue to resource, synchronously realizes high-efficiency recovery (more than or equal to 80 percent) of fiber, deep removal (more than 90 percent) of large adhesive and energy utilization of scum, and solves the treatment and disposal problems of terminal waste residue in the traditional process.

Inventors

  • FAN SHUJIE
  • SU ZHENHUA
  • LI NAN
  • ZHANG YU
  • YANG BIN
  • NI JIANPING
  • GONG CHEN
  • YAN JIPENG

Assignees

  • 中国制浆造纸研究院有限公司

Dates

Publication Date
20260512
Application Date
20260114

Claims (8)

  1. 1. The high-frequency fluffing-air floatation cooperative waste paper fine screening slag complete recycling system is characterized by comprising a high-frequency fluffing unit, an air floatation separating unit, a fiber recycling unit and a slag discharging energy unit which are sequentially connected and form a closed loop for recycling resources and energy; The high-frequency fluffing unit is used for mechanically fluffing the fine screening slag slurry at a slurry concentration of 0.5-1.1%; The air floatation separation unit is connected with the high-frequency fluffing unit and is used for carrying out air floatation separation on fluffed slurry, and controlling the slag discharge rate of the slurry to be 10% -20% so as to separate clean slurry and scum enriched with impurities; The fiber recovery unit is connected with the clean slurry outlet of the air flotation separation unit and is used for concentrating and storing the clean slurry or directly used for papermaking and pulping; the deslagging energy unit is connected with a scum discharge port of the air flotation separation unit and is used for converting the scum into solid fuel with a heat value not lower than 20MJ/kg or pyrolysis gas production.
  2. 2. The system of claim 1, wherein the slag removal and energy unit comprises a biomass shaping device for briquetting the solid fuel with dross having a dryness of greater than 35% after dehydration.
  3. 3. The system of claim 1, wherein the slag removal and energy unit comprises a pyrolysis gasification device for pyrolyzing the dewatered scum at a temperature of 500 ℃ to 600 ℃ to produce bio-oil and syngas.
  4. 4. A method for fully recycling fine waste paper tailings by using the system of claim 1, comprising the steps of: s1, fluffing, namely adjusting the concentration of the fine screening slag slurry for pulping waste paper to 0.5% -1.1%, and sending the slurry into a high-frequency fluffing unit for fluffing; s2, air floatation separation, namely delivering the defibered slurry into an air floatation separation unit, controlling the overall slag discharge rate to be 10% -20%, and separating clean slurry and scum; S3, recovering fibers, namely concentrating the clean slurry to 5% -12% of concentration, and placing the clean slurry in a good slurry storage tower or a high-concentration slurry storage tower or directly using the clean slurry for papermaking and pulping; S4, energy conversion, namely, after the scum is dehydrated, conveying the scum to a slag discharging energy unit to prepare biomass solid fuel with the heat value not lower than 20MJ/kg, or carrying out pyrolysis gasification to produce synthesis gas and biological oil.
  5. 5. The method according to claim 4, wherein in step S1, the operation ratio of the high-frequency fluffing unit is controlled to be in a range of 60 to 150j/m with respect to the boundary Load SPECIFIC EDGE Load, SEL.
  6. 6. The method according to claim 4, wherein in the step S2, a chemical agent composed of one or more chemicals selected from the group consisting of polydimethylsiloxane, sulfobetaine and ethylene oxide-propylene oxide block copolymers is added to the air flotation separation unit, wherein the ethylene oxide segments account for 45% -60% of the total mass of the ethylene oxide-propylene oxide block copolymer.
  7. 7. The method according to claim 4, wherein in the step S4, the dryness of the scum after dehydration is more than 35%, and the calorific value is 20-28 mj/kg.
  8. 8. The method of claim 4, wherein the method has a removal rate of greater than 90% for large stickies in the fine reject while having a recovery rate of no less than 80% for fiber.

Description

High-frequency fluffing-air floatation cooperative waste paper fine screening slag complete recycling system and method Technical Field The invention relates to the field of waste paper pulping technology and solid waste recycling, in particular to a system and a method for efficiently treating tailings generated in a waste paper pulping fine screening process and synchronously realizing fiber recovery and waste residue energy utilization. Background Waste paper pulping is an important way to save resources and protect the environment. In the pulping and purifying process, the fine screening process is used for removing fine impurities in the pulp, but the produced fine screening slag still contains about 30-50% of high-quality long fibers, and the fibers are difficult to directly recycle due to the fact that a large amount of adhesives, printing ink and other impurities adhere to the surface of the fibers. At present, enterprises generally simply recycle fine screening residues or treat the fine screening residues as solid wastes, wherein the fine screening residues cause vicious circulation of adhesives in a system to influence paper quality and equipment operation, and the fine screening residues cause fiber resource waste and environmental pollution. In the prior art, heat dispersion is an effective means for treating the adhesive, but the working of the adhesive needs to raise the concentration of slurry to a high concentration state of 20% -35% and be assisted by heating, which is seriously mismatched with the inherent low concentration (usually < 2%) of fine screen slag and the normal temperature state. If the technology is required to be applied, a large amount of equipment and process transformation are involved, and the cost and the difficulty are high. In addition, although the principle of treating fine screening slag by adopting high-frequency fluffing or air flotation separation is disclosed in the prior art, even the two are simply connected in series, but the fundamental defects are that the schemes are only focused on the impurity separation stage in the slurry, and an effective terminal disposal scheme is lacking for the high-heat-value scum generated after separation. In general, the dross enriched with impurities can only be treated as solid waste for outward transportation, which not only increases environmental risk and treatment cost, but also causes waste of resources, so that the whole process can not realize real recycling, and severely restricts the economic feasibility and large-scale application of the related technology in industry. Therefore, there is a need to develop a complete solution that can efficiently treat fine screening slag directly at low concentration and normal temperature, and can utilize the final waste slag in a high value. Disclosure of Invention The invention aims to solve the technical problem of overcoming the defects of the prior art and providing an integrated and industrialized high-frequency fluffing-air flotation collaborative waste paper fine screening slag complete recycling system and method. The system not only efficiently recovers fibers and deeply removes impurities through optimized unit cooperation and process parameter control, but also converts waste residues with high heat value into energy products, thereby realizing closed loop from waste treatment to resource and energy recovery. In order to solve the technical problems, the invention adopts the following technical scheme: In a first aspect, the invention provides a high-frequency fluffing-air floatation cooperative waste paper fine screening slag complete recycling system. The system comprises a high-frequency fluffing unit, an air flotation separation unit, a fiber recovery unit and a deslagging energy unit which are sequentially connected and form a closed loop for recycling resources and energy. The high-frequency fluffing unit is used for mechanically fluffing the fine screening slag slurry generated in the waste paper pulping process at the slurry concentration of 0.5-1.1% so as to peel off and disperse the adhesive, the printing ink and other hydrophobic impurities attached to the fiber surface. Preferably, the high-frequency fluffer is adopted by the high-frequency fluffer, and the tooth grinding gap is optimized to be 1.0+/-0.3 mm so as to avoid fiber damage while effectively stripping the adhesive. Further, the operation specific boundary Load (SPECIFIC EDGE Load, SEL) of the high-frequency fluffer is controlled within the range of 60-150J/m. And the feeding end of the air flotation separation unit is connected with the discharging end of the high-frequency fluffing unit and is used for carrying out air flotation separation treatment on fluffed slurry, and controlling the overall slag discharge rate of the system to be between 10 and 20 percent so as to separate clean slurry and scum enriched with impurities. Preferably, a flotation device with a bubble diameter of 0.5-2.0 mm i