Waste paper pulping system and method

Abstract

The invention discloses a waste paper pulping system and method, and relates to the technical field of papermaking, and the adopted technical scheme is that the waste paper pulping system comprises a waste paper repulping module, a high-concentration desanding module, a coarse screening module, a medium-concentration desanding module, a fiber grading treatment module, a pulp mixing module and a broken paper pulping module; white water separated by a first separator, a first drum screen, a second pulper, a second drum screen and a first slag washing tank in the waste paper repulping module flows back to the first pulper; the fiber grading treatment module comprises a first-section grading screen, a short fiber treatment module, a second-section grading screen, a medium fiber treatment module and a long fiber treatment module; the broke pulping module comprises a broke pulp tower, a high-concentration sand remover, a broke thickener, a concentrated pulp tank and a fluffer, and paper pulp treated by the fluffer enters the first-section grading screen. According to the invention, the fiber loss rate in the impurity removal process is reduced; grading the paper pulp into short fibers, medium fibers and long fibers, and then respectively treating the short fibers, the medium fibers and the long fibers; the damaged paper pulp is prevented from directly entering the pulp preparation to cause concentration and quantitative fluctuation.

Description

Technical Field

[0001] The invention relates to the technical field of papermaking, and in particular to a waste paper pulping system and method. Background Art

[0002] Waste paper is a waste in people's daily work and life, and is recyclable garbage suitable for recycling and resource utilization. The recycling of waste paper can generate huge economic and environmental benefits in reducing pollution, improving the environment, saving virgin fiber resources and energy, and protecting forest resources. It is a very important aspect of achieving sustainable development of the paper industry and social sustainable development.

[0003] However, due to the different environments in which people live, the source, quality, packaging and storage conditions of recycled waste paper are extremely complex. Waste paper contains a large amount of plastic, rags, metal, paraffin, asphalt, ink, adhesives, bricks, dust, glass, wood, chemical additives and polymer coatings that are not suitable for papermaking. Therefore, how to use waste paper to obtain the most available fiber, maximize the disposal of debris, protect the health of industrial workers, produce good quality pulp, and obtain the best quality paper is the most troublesome problem in the pulp preparation process.

[0004] The Chinese patent with application number 202110105995.8 in the related technology discloses a waste paper pulping system and process, including a pulping module, a first deslagging module, a coarse screening module, a second deslagging module, a fiber grading fine screening module and a pulping module, a fiber grading screen, a short fiber processing submodule and a long fiber processing submodule; the first deslagging module is used to remove some impurities in the pulp before entering the coarse screening module, and the second deslagging module is used to remove some impurities in the pulp before entering the fiber grading fine screening module again; the pulp is divided into short fiber slurry and long fiber slurry by the fiber grading screen, and the short fiber slurry and the long fiber slurry are processed respectively by the short fiber processing submodule and the long fiber processing submodule, and the tearing, delamination, brooming, bending, crushing and rubbing of the long fibers or short fibers are significant, and the cutting is less, so as to effectively produce high-quality pulp, thereby improving the quality of the finished paper.

[0005] With respect to the above technology, the inventors believe that there are still problems such as large fiber loss, unclean debris handling, and poor pulp quality, which affect the quality of finished paper. Summary of the invention

[0006] In view of the problems in the prior art such as large fiber loss, unclean debris treatment, and poor pulp quality, the present invention provides a waste paper pulping system and method.

[0007] The present invention provides the following technical solution: a waste paper pulping system, comprising a waste paper shredding module, a high-consistency sand removal module, a coarse screening module, a medium-consistency sand removal module, a fiber classification processing module, a pulp preparation module and a broken paper pulping module; The waste paper disintegration module comprises a first pulper, impurities discharged from the first pulper enter a first sedimentation well, light residues discharged from the first sedimentation well enter a first separator, a first drum screen, a second pulper, and a second drum screen in sequence, heavy residues discharged from the first sedimentation well enter a first residue washing tank, and white water separated by the first separator, the first drum screen, the second pulper, the second drum screen, and the first residue washing tank all flows back to the first pulper; The fiber grading processing module includes a first-stage grading screen, and two material outlets of the first-stage grading screen are respectively connected to the short fiber processing module and the second-stage grading screen, and two material outlets of the second-stage grading screen are respectively connected to the medium fiber processing module and the long fiber processing module; the short fiber processing module includes a short fiber desanding module, a short fiber concentrator, and a short fiber pulp tank which are arranged in sequence, the medium fiber processing module includes a medium fiber desanding module, a medium fiber concentrator, a medium fiber heat dispersion system, and a medium fiber pulp tank which are arranged in sequence, and the long fiber processing module includes a long fiber desanding module, a long fiber fine screening module, a long fiber concentrator, a long fiber heat dispersion system, a long fiber pulping machine, and a long fiber post-grinding pulp tank which are arranged in sequence; The broke paper pulping module comprises a broke paper pulp tower, a high-concentration desander, a broke paper thickener, a thickening pulp tank and a deflaker which are arranged in sequence, and the pulp processed by the deflaker enters the first-stage grading screen.

[0008] Preferably, the first pulper is further provided with a rope cutter, and the impurities discharged from the rope cutter are chopped and transferred to the second pulper.

[0009] Preferably, the second pulper is also connected to a second sedimentation well, the light residue separated in the second sedimentation well is sent back to the second pulper, the heavy residue separated in the second sedimentation well enters a second residue washing tank, and the white water separated in the second residue washing tank flows back to the first pulper.

[0010] Preferably, the high-concentration sand removal module includes a high-concentration sand remover; the coarse screening module includes a primary coarse screen, the good pulp separated by the high-concentration sand remover enters the primary coarse screen, the screened material of the primary coarse screen enters the secondary coarse screen, the screened material of the secondary coarse screen enters the third separator, and the good pulp separated by the primary coarse screen and the secondary coarse screen enters the medium-concentration sand removal module; the good pulp separated by the third separator returns to the secondary coarse screen, and the sludge pulp enters the fourth separator, and the white water separated by the fourth separator flows back to the primary coarse screen.

[0011] Preferably, the medium-consistency desander module comprises multiple sections of medium-consistency desanders connected in sequence, wherein the latter section of the medium-consistency desander processes impurities of the former section of the medium-consistency desander and returns the separated good slurry to the former section of the medium-consistency desander.

[0012] Preferably, the short fiber desanding module, the medium fiber desanding module and the long fiber desanding module all comprise multiple sections of low-concentration desanding devices connected in sequence, and the latter section of the low-concentration desanding device processes the impurities of the former section of the low-concentration desanding device and returns the separated good pulp to the former section of the low-concentration desanding device.

[0013] Preferably, the long fiber fine screening module comprises a first-stage fine screen, a second-stage fine screen and a third-stage fine screen connected in sequence, the good pulp separated by the long fiber sand removal module enters the first-stage fine screen, the residue pulp separated by the first-stage fine screen enters the second-stage fine screen, the residue pulp separated by the second-stage fine screen enters the third-stage fine screen, the good pulp separated by the first-stage fine screen and the second-stage fine screen enters the long fiber concentrator, and the good pulp separated by the three-stage fine screen enters the second-stage fine screen.

[0014] Preferably, the slurry preparation module includes a slurry preparation tank, a slurry forming tank, a slurry stabilizing box, a white water tower, a primary slurry flushing pump, and a first-stage slurry preparation desander, which are arranged in sequence. The good slurry separated by the first-stage slurry preparation desander enters the degasser, the secondary slurry flushing pump, and the primary pressure screen in sequence, and the good slurry separated by the primary pressure screen enters the pulse attenuation tank and the headbox in sequence; the slag slurry separated by the first-stage slurry preparation desander enters the second-stage slurry preparation desander, the slag slurry separated by the second-stage slurry preparation desander enters the third-stage slurry preparation desander, the slag slurry separated by the third-stage slurry preparation desander enters the long fiber desanding module, the good slurry separated by the second-stage slurry preparation desander enters the white water tower, and the good slurry separated by the third-stage slurry preparation desander enters the second-stage slurry preparation desander; the slag slurry separated by the primary pressure screen enters the secondary pressure screen, the good slurry separated by the secondary pressure screen flows back to the white water tower, and the slag slurry enters the first-stage grading screen.

[0015] A waste paper pulping method, applied to the waste paper pulping system, comprises the following steps: S1, shredding; removing dust and residue from waste paper, and recovering useful fibers from the residue; S2, high-concentration sand removal: the first purification of the crushed pulp to remove heavy impurities; S3, coarse screening; the second purification of pulp to remove light impurities; S4, medium-consistency sand removal; the pulp is purified for the third time to remove heavy impurities again; S5, fiber classification and processing; classifying the pulp into short fiber pulp, medium fiber pulp and long fiber pulp according to the fiber length; For short fiber pulp, remove impurities heavier than short fibers and concentrate; For medium fiber pulp, remove impurities heavier than medium fiber, concentrate, and heat disperse; For long fiber pulp, remove impurities heavier and larger than long fibers, then concentrate, heat disperse, and refine; S6, slurry preparation: short fibers, medium fibers, long fibers and other fibers and additives are used to prepare slurry according to the proportion, and after the slurry is adjusted to the appropriate concentration, heavy impurities and free air are removed, and then large impurities are removed, and pressure pulses are eliminated before entering the papermaking operation; S7, broken paper recovery; the broken paper is shredded and sent to the pulp tower to balance the concentration and absorb water for swelling, and then the heavy impurities are removed, concentrated, and high-frequency decomposition is carried out before being sent to S5.

[0016] The beneficial effects of the present invention are as follows: 1. During the crushing process, the slag is removed, the waste slag is graded, and then the fibers mixed in the waste slag are recovered through multiple treatments to avoid fiber loss; through three purifications of high-concentration sand removal, coarse screening and medium-concentration sand removal, coarse and large impurities are removed step by step, and the fiber loss rate during the impurity removal process is reduced; 2. The pulp is graded into short fibers, medium fibers and long fibers, and then low-concentration sand removal, screening, concentration, thermal dispersion and pulping are performed on the short fibers, medium fibers and long fibers respectively to further remove impurities in the pulp, and light impurities such as ink particles, hot melt adhesives and plastic particles in the pulp are dispersed into small particles that are invisible to the naked eye, thereby improving the quality of the pulp and ultimately improving the quality of the paper; 3. By removing the short fibers, medium fibers and long fibers, the paper pulp is further refined and the fiber is refining, ... , long fibers and other fibers and additives are pulped, mixed evenly and adjusted in concentration, and then desanded, degassed, screened and pulse attenuated to remove heavy impurities, free air, large impurities and pressure pulses, improve pulp quality, improve paper sheet formation, reduce the occurrence of paper diseases, and thus improve paper quality; 4. The broken paper produced in the papermaking process is broken into pulp, which is desanded, concentrated and deflated at high concentrations, and then enters the grading screen for fiber classification before entering the pulping process to avoid broken paper pulp directly entering the pulping process, causing concentration fluctuations in the pulping system and paper quantity fluctuations; 5. No chemical agents are used in the entire pulping process, waste water is reused in the production process, and waste residues can be classified and recycled after being transported out, without generating new environmental pollution, with good environmental and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of one embodiment of a pulping system.

[0018] Figure 2 A flowchart of an embodiment of a fiber classification processing module.

[0019] Figure 3 The present invention is a flow chart of an embodiment of a slurry distribution module.

[0020] Figure 4 The figure is a flow chart of one embodiment of a broke pulping module.

[0021] Figure numerals: 10-waste paper shredding module, 20-high-concentration sand removal module, 30-coarse screening module, 40-medium-concentration sand removal module, 50-fiber classification processing module, 51-short fiber processing module, 511-short fiber sand removal module, 52-medium fiber processing module, 521-medium fiber sand removal module, 53-long fiber processing module, 531-long fiber sand removal module, 532-long fiber fine screening module, 60-pulping module, 70-broken paper pulping module. DETAILED DESCRIPTION

[0022] The following is a more detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and the accompanying drawings so that a person skilled in the art can implement the embodiments after reading the description. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] Example 1

[0024] The present invention provides Figure 1-4 The waste paper pulping system shown includes a waste paper disintegrating module 10 , a high-consistency sand removal module 20 , a coarse screening module 30 , a medium-consistency sand removal module 40 , a fiber classification processing module 50 , a pulp preparation module 60 and a broken paper pulping module 70 .

[0025] The waste paper disintegration module 10 includes a first pulper. The first pulper may be a hydraulic pulper. After the waste paper bundled with steel wires is sheared by the wire shearing machine, it is transported to the first pulper by the conveyor to be disintegrated into paper pulp. In order to avoid dust pollution in the working environment during the above process, the wire shearing machine, the conveyor, and the first pulper may be covered with a dust cover. The air exhaust port of the dust cover is connected to a bag-type dust collector and an air exhauster to suck the dust into the bag-type dust collector for filtration, and the collected dust is transported to a landfill for treatment.

[0026] The pulp crushed by the first pulper is discharged to the high-concentration sand removal module 20 for processing, and the separated impurities are divided into two parts and processed by the rope twister and the first sedimentation well. Among them, the larger impurities such as steel wire, plastic, rags, etc. are entangled with the rope twister and discharged, and then chopped and transferred to the second pulper. After the impurities are stirred and dispersed, the fibers mixed in them are recovered. Smaller impurities such as sand, gravel, plastic, and ironware enter the first sedimentation well; heavy slag with higher density falls to the bottom of the first sedimentation well, and is then transferred by a crane to the first slag washing tank for cleaning. The fibers attached to the heavy slag are flushed back to the first pulper for recovery, and the remaining impurities are discharged and transported out; light slag with lower density enters the first separator, the first drum screen, the second pulper, and the second drum screen in turn for dehydration and classification, and the fiber-containing white water flows back to the first pulper, and the impurities are discharged and transported out; the heavy slag separated by the second pulper enters the second sedimentation well for further mixing, dispersion, and classification, wherein the light slag enters the second drum screen with the white water, and the heavy slag enters the second sedimentation well, and the light slag and white water separated in the second sedimentation well flow back to the second pulper, and the heavy slag enters the second slag washing tank for cleaning, and the fiber-containing white water flows back to the first pulper, and the impurities are discharged and transported out. Through the above steps, the fibers mixed and attached to the impurities are repeatedly recovered to the first pulper to reduce the fiber loss rate. The first separator can be a fiber separator.

[0027] The high-density desander module 20 includes a high-density desander to perform the first purification of the pulp. The high-density desander uses centrifugal force to separate sand, iron slag and fiber suspension according to the density of each component in the pulp. The fiber suspension with low density forms good pulp, leaves the high-density desander from the top, and enters the coarse screening module 30 through the unloading slurry pool; sand, iron slag and other slag leave the high-density desander from the bottom of the high-density desander and enter the second separator for dehydration. The second separator can be a sand-water separator.

[0028] The coarse screen module 30 performs a second purification on the pulp. The good pulp separated by the high-concentration desander enters the primary coarse screen, the screened material of the primary coarse screen enters the secondary coarse screen, the screened material of the secondary coarse screen enters the third separator, and the good pulp separated by the primary coarse screen and the secondary coarse screen enters the medium-concentration desander module 40; the third separator separates the fiber from impurities such as plastic and foam, and the separated good pulp returns to the secondary coarse screen, and the slag pulp enters the fourth separator to separate the impurities again and dehydrate, and the white water separated by the fourth separator flows back to the primary coarse screen, and the impurities are discharged and transported out. The third separator can be a fiber separator, and the fourth separator can be a slag separator.

[0029] The medium-consistency desander module 40 performs a third purification of the pulp and separates impurities, including a first-stage medium-consistency desander, a second-stage medium-consistency desander, a third-stage medium-consistency desander, and a fourth-stage medium-consistency desander connected in sequence. Among the multiple-stage medium-consistency desanders, the latter stage medium-consistency desander processes the impurities of the former stage medium-consistency desander and returns the separated good pulp to the former stage medium-consistency desander. The good pulp separated by the first stage medium-consistency desander is screened into the pulp pool and enters the fiber classification processing module 50. The slag pulp separated by the fourth stage medium-consistency desander can also enter the fifth separator for dehydration, and the impurities are discharged and transported. The fifth separator can be a sand-water separator.

[0030] The fiber classification processing module 50 processes the pulp after classification, and includes a first-stage classification screen, a second-stage classification screen, a short fiber processing module 51, a medium fiber processing module 52, and a long fiber processing module 53. The first-stage classification screen performs the initial classification, and separates the short fiber suspension with a smaller size into the short fiber processing module 51, and the second-stage classification screen classifies the remaining pulp again, and separates the medium fiber suspension with a moderate size and the long fiber suspension with a larger size, and enters the medium fiber processing module 52 and the long fiber processing module 53 respectively.

[0031] The short fiber processing module 51 includes a short fiber desander module 511, a short fiber concentrator, and a short fiber pulp tank, which are arranged in sequence to purify the short fiber suspension. The short fiber desander module 511 includes a short fiber first stage desander and a short fiber second stage desander connected in sequence, both of which are low-concentration desanders to remove some impurities; the short fiber suspension first enters the short fiber first stage desander, and the good pulp with lower density enters the short fiber concentrator, and enters the short fiber pulp tank after the concentration is increased and balanced. The residue pulp mixed with impurities has a higher density and enters the short fiber second stage desander; the suspension with lower density in the short fiber second stage desander flows back to the short fiber first stage desander, and the residue pulp enters the long fiber processing module 53.

[0032] The medium fiber processing module 52 includes a medium fiber desanding module 521, a medium fiber concentrator, a medium fiber heat dispersion system, and a medium fiber slurry tank, which are arranged in sequence to purify the medium fiber suspension. The medium fiber desanding module 521 includes a medium fiber first stage desanding device, a medium fiber second stage desanding device, and a medium fiber third stage desanding device, which are connected in sequence. All three use low-concentration desanding devices to remove some impurities. The medium fiber suspension first enters the medium fiber first stage desander, and the separated good pulp enters the medium fiber concentrator. After the concentration is increased and balanced, it enters the medium fiber thermal dispersion system, and the medium fiber is thermally dispersed so that the light impurities such as ink particles, hot melt adhesive and plastic particles in the medium fiber are dispersed into small particles invisible to the naked eye under the action of high temperature and rubbing. After thermal dispersion treatment, the pulp enters the medium fiber pulp pool for standby; the slag pulp separated by the medium fiber first stage desander enters the medium fiber second stage desander, and the good pulp separated by the medium fiber second stage desander flows back to the medium fiber first stage desander, and the slag pulp enters the medium fiber third stage desander; the good pulp separated by the medium fiber third stage desander flows back to the medium fiber second stage desander, and the slag pulp enters the long fiber processing module 53.

[0033] The long fiber processing module 53 includes a long fiber sand removal module 531, a long fiber fine screening module 532, a long fiber concentrator, a long fiber heat dispersion system, a long fiber refiner, and a long fiber post-refining pulp tank, which are arranged in sequence to purify the long fiber suspension.

[0034] The long fiber desander module 531 includes a long fiber first stage desander, a long fiber second stage desander, a long fiber third stage desander, and a long fiber fourth stage desander, which are connected in sequence, and all use low-concentration desanders to remove some impurities. The long fiber suspension first enters the long fiber first stage desander, and the separated good pulp enters the long fiber fine screening module 532, and the slag pulp enters the long fiber second stage desander; the good pulp separated by the long fiber second stage desander flows back to the long fiber first stage desander, and the slag pulp enters the long fiber third stage desander, and the slag pulp from the medium fiber second stage desander and the short fiber second stage desander also flows to the long fiber third stage desander; the good pulp separated by the long fiber third stage desander flows back to the long fiber second stage desander, and the slag pulp enters the long fiber fourth stage desander; the good pulp separated by the long fiber fourth stage desander flows back to the long fiber third stage desander, and the slag pulp can enter the fifth separator for dehydration.

[0035] The long fiber fine screening module 532 includes a first-stage fine screen, a second-stage fine screen and a third-stage fine screen connected in sequence, which are used to remove fibers that are too long. The pulp from the first-stage desander of the long fiber first enters the first-stage fine screen, the slag pulp separated by the first-stage fine screen enters the second-stage fine screen, and the good pulp separated by the first and second-stage fine screens enters the long fiber concentrator to complete concentration improvement and balance, and then is sent to the long fiber thermal dispersion system to perform thermal dispersion treatment on the long fibers, so that the light impurities such as ink particles, hot melt adhesives and plastic particles in the long fibers are dispersed into small particles invisible to the naked eye under high temperature and rubbing; after thermal dispersion treatment, the pulp enters the pulping machine through the long fiber mill pre-pulp pool for pulping treatment, and changes the physical properties of the fiber such as length, diameter, uniformity, etc. through physical effects such as mechanical shearing, friction, and extrusion, so that the fiber becomes soft, easy to absorb water and swell and become fine fibers, so that good dehydration and forming are obtained during papermaking, and the uniformity, smoothness and mechanical strength of the paper sheet are improved; after pulping, the long fiber pulp enters the long fiber mill post-pulp pool for standby. The residue pulp separated by the second stage fine screening enters the third stage fine screening, and the larger fibers are returned to the first pulper with the residue pulp of the third stage fine screening to be broken again, and the good pulp separated by the third stage fine screening returns to the second stage fine screening.

[0036] The pulp preparation module 60 includes a pulp preparation tank, a pulp preparation tank, a stabilizing tank, a white water tower, a primary pulp flushing pump, and a first-stage pulp preparation desander. According to the process ratio requirements, short fibers, medium fibers, long fibers and other fibers and additives are used in proportion to prepare pulp in the pulp preparation tank; the pulp obtained after pulp preparation is mixed evenly and the concentration is balanced in the pulp preparation tank and the stabilizing tank; white water is added to the white water tower to adjust the concentration; and the pulp is sent to the first-stage pulp preparation desander for purification through the primary pulp flushing pump.

[0037] The first-stage desander of pulp preparation classifies the pulp according to the density of each component in the pulp. The good pulp with lower density enters the deaerator. Under the vacuum inside the deaerator, the boiling point of the liquid is reduced, and the air is removed from the pulp and sucked away by the vacuum suction machine, which reduces the occurrence of paper defects such as blistering, rough edges and pinholes during papermaking and sheet forming, improves sheet forming and paper quality; the slag pulp with higher density enters the second-stage desander of pulp preparation for further purification. The good pulp separated by the second-stage desander of pulp preparation is sent back to the white water tower, and the slag pulp enters the third-stage desander of pulp preparation for further purification. The good pulp separated by the third-stage desander of pulp preparation is sent back to the second-stage desander of pulp preparation, and the slag pulp is transported to the third-stage desander of long fiber for centralized treatment.

[0038] The degassed pulp is sent to the primary pressure screen through the secondary flushing pump, and the smaller fibers form good pulp and are sent to the pulse attenuation tank to eliminate and suppress the pressure pulses of the pulp during transportation and production, reduce the lateral and longitudinal quantitative fluctuations of the pulp during papermaking and paper sheet forming, ensure the pulp stability and paper quality, and finally be sent to the headbox to be made into paper sheets; the larger fibers become slag pulp and enter the secondary pressure screen, the good pulp separated by the secondary pressure screen flows back to the white water tower, and the slag pulp is transported to a grading screen.

[0039] Broke paper pulping module 70 is used to process broken paper generated in the production process, and the broken paper includes broken paper from the paper machine couch roll, pressing, sizing, calendering, winding and rewinding paper edges. Broke paper pulping module 70 includes a broken paper pulp tower, a high-consistency desander, a broken paper thickener, a thickening pulp tank and a deflaker, which are arranged in sequence. The pulp processed by the deflaker enters the first-stage grading screen. Broken paper from different sources has different dryness and generation conditions, and needs to be broken by pulpers of different specifications, and then sent to a broken paper pulp tower to balance the concentration and water absorption swelling; then sent to a high-concentration desander to remove heavy impurities according to the density of each component in the pulp; the pulp coming out of the high-concentration desander is sent to a broken paper thickener for concentration to ensure that the concentration of the broken paper pulp is maintained within the range required by the process; the concentrated broken paper pulp is sent to a deflaker for deflaking to disperse the coarse fibers and incompletely dispersed paper pieces or pulp clumps in the pulp; finally, the broken paper pulp is sent to a grading screen, mixed with waste paper pulp, and enters the fiber grading processing module 50 for grading and processing.

[0040] Example 2

[0041] A waste paper pulping method, applied to the waste paper pulping system described in Example 1, comprises the following steps: S1, shredding; removing dust and residue from waste paper, and recovering useful fibers from the residue; S2, high-concentration sand removal: the first purification of the crushed pulp is carried out to remove heavy impurities according to the density differences of the components in the pulp; S3, coarse screening; the second purification of the pulp, according to the size difference of each component in the pulp, removes light impurities; S4, medium-consistency sand removal; the third purification of the pulp, based on the density differences of the various components in the pulp, to remove heavy impurities again; S5, fiber classification and processing; classifying the pulp into short fiber pulp, medium fiber pulp and long fiber pulp according to the fiber length; For short fiber pulp, remove impurities heavier than short fibers and concentrate to ensure that the concentration of short fibers is maintained within the range required by the process; For medium fiber pulp, remove impurities heavier than medium fiber, concentrate to ensure that the concentration of medium fiber is maintained within the range required by the process, and then disperse it thermally so that light impurities such as ink particles, hot melt adhesive and plastic particles in the medium fiber are dispersed into small particles invisible to the naked eye under the action of high temperature and kneading; For long fiber pulp, remove impurities heavier and larger than the long fibers, then concentrate to ensure that the concentration of the long fibers is maintained within the range required by the process, and then heat disperse to disperse the light impurities such as ink particles, hot melt adhesives and plastic particles in the long fibers into small particles invisible to the naked eye under high temperature and kneading. Finally, grind the pulp to change the physical properties of the fibers such as length, diameter, uniformity, etc. through physical actions such as mechanical shearing, friction, and extrusion, making the fibers softer, easier to absorb water and swell, and fine fiber, so as to obtain good dehydration and formation during papermaking, and improve the uniformity, smoothness and mechanical strength of the paper sheets; S6, slurry preparation: short fibers, medium fibers, long fibers and other fibers and additives are used to prepare slurry according to the proportion, and after the slurry is adjusted to the appropriate concentration, heavy impurities and free air are removed, and then large impurities are removed, and pressure pulses are eliminated before entering the papermaking operation; S7, broken paper recovery; the broken paper is shredded and sent to the pulp tower to balance the concentration and absorb water for swelling, and then the heavy impurities are removed, concentrated, and high-frequency decomposition is carried out before being sent to S5.

[0042] The above are one or more embodiments of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A waste paper pulping system, comprising a waste paper disintegration module, a high-consistency sand removal module, a coarse screening module, a medium-consistency sand removal module, a fiber classification processing module, a pulp preparation module and a broke paper pulping module, characterized in that: The waste paper disintegration module comprises a first pulper, impurities discharged from the first pulper enter a first sedimentation well, light residues discharged from the first sedimentation well enter a first separator, a first drum screen, a second pulper, and a second drum screen in sequence, heavy residues discharged from the first sedimentation well enter a first residue washing tank, and white water separated by the first separator, the first drum screen, the second pulper, the second drum screen, and the first residue washing tank all flows back to the first pulper; The fiber grading processing module includes a first-stage grading screen, and two material outlets of the first-stage grading screen are respectively connected to the short fiber processing module and the second-stage grading screen, and two material outlets of the second-stage grading screen are respectively connected to the medium fiber processing module and the long fiber processing module; the short fiber processing module includes a short fiber desanding module, a short fiber concentrator, and a short fiber pulp tank which are arranged in sequence, the medium fiber processing module includes a medium fiber desanding module, a medium fiber concentrator, a medium fiber heat dispersion system, and a medium fiber pulp tank which are arranged in sequence, and the long fiber processing module includes a long fiber desanding module, a long fiber fine screening module, a long fiber concentrator, a long fiber heat dispersion system, a long fiber pulping machine, and a long fiber post-grinding pulp tank which are arranged in sequence; The broke paper pulping module comprises a broke paper pulp tower, a high-concentration desander, a broke paper thickener, a thickening pulp tank and a deflaker which are arranged in sequence, and the pulp processed by the deflaker enters the first-stage grading screen.

2. A waste paper pulping system according to claim 1, characterized in that: The first pulper is also provided with a rope twister, and the impurities discharged from the rope twister are chopped and transferred to the second pulper.

3. A waste paper pulping system according to claim 1, characterized in that: The second pulper is also connected to a second sedimentation well, the light residue separated in the second sedimentation well is sent back to the second pulper, the heavy residue separated in the second sedimentation well enters the second residue washing tank, and the white water separated in the second residue washing tank flows back to the first pulper.

4. A waste paper pulping system according to claim 1, characterized in that: The high-concentration sand removal module includes a high-concentration sand remover; the coarse screening module includes a primary coarse screen, the good pulp separated by the high-concentration sand remover enters the primary coarse screen, the screened material of the primary coarse screen enters the secondary coarse screen, the screened material of the secondary coarse screen enters the third separator, and the good pulp separated by the primary coarse screen and the secondary coarse screen enters the medium-concentration sand removal module; the good pulp separated by the third separator returns to the secondary coarse screen, and the slag pulp enters the fourth separator, and the white water separated by the fourth separator flows back to the primary coarse screen.

5. A waste paper pulping system according to claim 1, characterized in that: The medium-consistency desander module comprises a plurality of medium-consistency desanders connected in sequence. Among the plurality of medium-consistency desanders, the latter medium-consistency desander processes the impurities of the former medium-consistency desander and returns the separated good slurry to the former medium-consistency desander.

6. A waste paper pulping system according to claim 1, characterized in that: The short fiber desanding module, the medium fiber desanding module and the long fiber desanding module all include multiple sections of low-concentration desanding devices connected in sequence, and the latter section of the low-concentration desanding device processes the impurities of the former section of the low-concentration desanding device and returns the separated good pulp to the former section of the low-concentration desanding device.

7. A waste paper pulping system according to claim 1, characterized in that: The long fiber fine screening module includes a first-stage fine screen, a second-stage fine screen and a third-stage fine screen connected in sequence. The good pulp separated by the long fiber sand removal module enters the first-stage fine screen, the residue pulp separated by the first-stage fine screen enters the second-stage fine screen, the residue pulp separated by the second-stage fine screen enters the third-stage fine screen, the good pulp separated by the first-stage fine screen and the second-stage fine screen enters the long fiber concentrator, and the good pulp separated by the third-stage fine screen enters the second-stage fine screen.

8. The waste paper pulping system according to claim 1, characterized in that: The slurry preparation module includes a slurry preparation tank, a slurry forming tank, a slurry stabilizing box, a white water tower, a primary slurry flushing pump, and a first-stage slurry preparation desander, which are arranged in sequence. The good slurry separated by the first-stage slurry preparation desander enters the degasser, the secondary slurry flushing pump, and the primary pressure screen in sequence, and the good slurry separated by the primary pressure screen enters the pulse attenuation tank and the headbox in sequence; the slag slurry separated by the first-stage slurry preparation desander enters the second-stage slurry preparation desander, the slag slurry separated by the second-stage slurry preparation desander enters the third-stage slurry preparation desander, the slag slurry separated by the third-stage slurry preparation desander enters the long fiber desanding module, the good slurry separated by the second-stage slurry preparation desander enters the white water tower, and the good slurry separated by the third-stage slurry preparation desander enters the second-stage slurry preparation desander; the slurry separated by the primary pressure screen enters the secondary pressure screen, the good slurry separated by the secondary pressure screen flows back to the white water tower, and the slag slurry enters the first-stage grading screen.

9. A waste paper pulping method, applied to the waste paper pulping system according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, shredding; removing dust and residue from waste paper, and recovering useful fibers from the residue; S2, high-concentration sand removal: the first purification of the crushed pulp to remove heavy impurities; S3, coarse screening; the second purification of pulp to remove light impurities; S4, medium-consistency sand removal; the pulp is purified for the third time to remove heavy impurities again; S5, fiber classification and processing; classifying the pulp into short fiber pulp, medium fiber pulp and long fiber pulp according to the fiber length; For short fiber pulp, remove impurities heavier than short fibers and concentrate; For medium fiber pulp, remove impurities heavier than medium fiber, concentrate, and heat disperse; For long fiber pulp, remove impurities heavier and larger than long fibers, then concentrate, heat disperse, and refine; S6, slurry preparation; Use short fibers, medium fibers, long fibers and other fibers and additives in proportion to prepare the slurry. After the slurry is adjusted to the appropriate concentration, remove heavy impurities and free air, then remove larger impurities and eliminate pressure pulses before entering the papermaking operation. S7, broken paper recovery; the broken paper is shredded and sent to the pulp tower to balance the concentration, absorb water and swell, and then remove heavy impurities, concentrate, and high-frequency deflocculate before being sent to S5.

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