A system for producing white lime mud pulp of grade A3 kraft paper

Abstract

This utility model relates to a white pulp production system for A3 grade kraft paper, comprising: a chain conveyor for conveying white pulp residue recovered from a wastewater treatment plant to a pulper; a pulper for pulping the white pulp residue conveyed by the chain conveyor and then sending it to a high-consistency desander; a high-consistency desander for removing desander from the pulper and then sending it to a discharge pulp tower; a discharge pulp tower for storing the pulp after desandering by the high-consistency desander; a discharge pump for sending the pulp in the discharge pulp tower to a low-consistency desander; a low-consistency desander for removing desander from the pulp conveyed by the discharge pump and then sending it to a thermal dispersion system; a thermal dispersion system for thermally dispersing the pulp and then sending it to a medium-fiber storage tower; and a storage tower for storing the pulp after thermal dispersion treatment. By treating the white pulp residue recovered from the paper mill wastewater treatment plant, it can replace domestic waste white pulp, optimize the process flow, and reduce raw material costs.

Description

Technical Field

[0001] This application relates to the field of papermaking technology, specifically to a white pulp production system for A3 grade kraft paper. Background Technology

[0002] With the continuous development of the paper industry and strict control over imported waste paper, the adjustment of paper brightness (L value = 57±1) in the current production of A3 grade coated kraft paper is mainly achieved by adding domestic waste bleached paper (secondary recycled white waste paper) to the OCC line (waste corrugated cardboard box recycling line). The process flow is as follows: after mixing domestic waste bleached paper with domestic waste ABCD grade waste paper, the mixture is fed into the pulping mill. After a full process of slag removal, grading, and screening, only about 30% of the white pulp enters the medium fiber pulp tower for surface pulp preparation.

[0003] However, after full-process treatment, only about 30% of the white pulp from domestic waste bleached paper enters the medium fiber system, while the remaining 70% goes to the long and short fiber systems. This low white pulp yield leads to raw material waste and increased costs. Furthermore, the adjustment response time is long, taking more than 3 hours from feeding to the paper machine mixing tank, making it difficult to quickly respond to fluctuations in paper color (L value = 57±1, a value = 8.3±0.3, b value = 20.6±0.3). The price of domestic waste bleached paper is significantly affected by market fluctuations, resulting in strong raw material dependence and high costs. Utility Model Content

[0004] In view of the above problems, this application provides a white pulp production system for A3 grade kraft paper, which solves the problem of high raw material costs in the existing A3 grade kraft paper production process that uses domestic waste white pulp.

[0005] To achieve the above objectives, the inventors provide a white pulp production system for A3 grade kraft paper, comprising:

[0006] A chain conveyor, used to transport white slurry residue recovered from a wastewater treatment plant to a pulper;

[0007] A pulper, which is used to pulp the white pulp residue conveyed by the chain conveyor and then send it to a high-consistency slag remover;

[0008] A high-consistency slag remover is used to remove slag from the pulp fed into the pulper before sending it into the discharge slurry tower.

[0009] The unloading slurry tower is used to store the slurry after the high-concentration slag remover has removed slag.

[0010] A discharge pump is used to deliver slurry from the discharge slurry tower into a low-concentration slag remover.

[0011] A low-concentration slag remover is used to remove slag from the slurry delivered by the unloading pump before sending it into the thermal dispersion system.

[0012] A thermal dispersion system, wherein the thermal dispersion system is used to thermally disperse the slurry before feeding it into a medium fiber slurry storage tower;

[0013] A slurry storage tower, used for storing slurry after thermal dispersion treatment.

[0014] In some embodiments, the thermal dispersion system includes;

[0015] A pressing screw, the inlet of which is connected to the outlet of the low-concentration slag remover;

[0016] A feed plug screw, wherein the feed inlet of the feed plug screw is connected to the discharge outlet of the pressing screw;

[0017] A crushing spiral, wherein the feed inlet of the crushing spiral is connected to the discharge outlet of the feed plug spiral;

[0018] A heating spiral, wherein the feed inlet of the heating spiral is connected to the discharge outlet of the crushing spiral;

[0019] A feeding screw, wherein the inlet of the feeding screw is connected to the outlet of the heating screw;

[0020] A thermal disperser, wherein the feed inlet of the thermal disperser is connected to the discharge outlet of the heating screw, and the discharge outlet of the thermal disperser is connected to the medium fiber slurry storage tower.

[0021] In some embodiments, the heating spiral is a steam-heating spiral.

[0022] In some embodiments, it also includes:

[0023] A flow meter is installed on the slurry supply pipeline between the unloading slurry tower and the medium fiber low concentration slag remover.

[0024] An automatic regulating valve is connected to the flow meter and is installed on the slurry supply pipeline between the unloading slurry tower and the medium fiber low concentration slag remover.

[0025] In some embodiments, the chain conveyor, pulper, high-consistency slag remover, and unloading slurry tower are the chain conveyor, pulper, high-consistency slag remover, and unloading slurry tower of the BKP line.

[0026] In some embodiments, it also includes:

[0027] A lightweight slag remover is disposed between the low-concentration slag remover and the thermal dispersion system.

[0028] In some embodiments, the low-concentration slag remover, light slag remover, thermal dispersion system, and slurry storage tower are low-concentration slag removers, light slag removers, thermal dispersion systems, and slurry storage towers of the OCC medium fiber system.

[0029] In some embodiments, it also includes:

[0030] A pulp pump, the inlet of which is connected to the pulp storage tower, is used to deliver the pulp in the pulp storage tower into the paper machine mixing tank.

[0031] Unlike existing technologies, the above-mentioned technical solution uses a chain conveyor to output the white pulp residue recovered from the papermaking wastewater treatment plant to a pulper for pulping. After pulping, it is sent to a high-consistency desander to remove heavy impurities and improve the cleanliness of the pulp. Then, it is sent to a discharge pulp tower, and the pulp in the discharge pulp tower is sent to a low-consistency desander by a discharge pump to remove fine impurities. Finally, it is sent to a thermal dispersion system to break down large particles of ink, adhesives, and other impurities in the pulp. This process reduces the impurities in the pulp and minimizes their harm to paper quality and paper machine operation. By treating the white pulp residue recovered from the papermaking wastewater treatment plant, it replaces domestic waste white pulp residue, optimizes the process flow, and reduces raw material costs.

[0032] The above description of the utility model is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the description and drawings, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is provided in conjunction with the specific embodiments and drawings of this application. Attached Figure Description

[0033] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of specific embodiments of this application and other related content, and should not be considered as limitations on this application.

[0034] In the accompanying drawings of the instruction manual:

[0035] Figure 1 This is a schematic diagram of a white pulp production system for A3 grade kraft paper as described in a specific embodiment;

[0036] Figure 2 This is a schematic diagram of a structure of the heat dispersion system described in a specific embodiment;

[0037] Figure 3 This is another structural schematic diagram of the white pulp production system for A3 grade kraft paper described in the specific implementation method;

[0038] Figure 4 This is another structural schematic diagram of the white pulp production system for A3 grade kraft paper described in the specific implementation method;

[0039] Figure 5 This is a schematic diagram of another structure of the white pulp production system for A3 grade kraft paper as described in a specific embodiment.

[0040] The reference numerals used in the above figures are explained as follows:

[0041] 110. Chain conveyor belt machine

[0042] 120. Pulping machine

[0043] 130. High-concentration slag remover

[0044] 140. Unloading slurry tower,

[0045] 150. Unloading pump

[0046] 160. Low-concentration slag remover

[0047] 170. Thermal dispersion system

[0048] 180. Slurry storage tower

[0049] 210. Pressing screw,

[0050] 220. Feed plug screw,

[0051] 230. Crushing Spiral

[0052] 240. Heating spiral,

[0053] 250. Feeding screw,

[0054] 260. Thermal disperser

[0055] 310. Flow meter

[0056] 320. Automatic regulating valve.

[0057] 410. Lightweight slag remover

[0058] 510. Slurry pump,

[0059] 520. Paper machine mixing tank. Detailed Implementation

[0060] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0061] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0062] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0063] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0064] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0065] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0066] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0067] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0068] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0069] Please see Figure 1 This embodiment provides a white pulp production system for A3 grade kraft paper, including:

[0070] Chain conveyor 110, which is used to transport white slurry residue recovered from sewage treatment plant to pulper 120;

[0071] Pulper 120 is used to pulp the white pulp residue conveyed by chain conveyor 110 and then send it to high-consistency slag remover 130.

[0072] High-consistency slag remover 130 is used to remove slag from the slurry fed into the pulper 120 and then send it into the unloading slurry tower 140.

[0073] The unloading slurry tower 140 is used to store the slurry after the high-concentration slag remover has removed slag;

[0074] The unloading pump 150 is used to send the slurry in the unloading slurry tower 140 into the low-concentration slag remover 160.

[0075] Low-concentration slag remover 160 is used to remove slag from the slurry delivered by the unloading pump 150 and then send it into the thermal dispersion system 170.

[0076] A thermal dispersion system 170 is used to thermally disperse the slurry before feeding it into a medium-fiber slurry storage tower 180.

[0077] The slurry storage tower 180 is used to store the slurry after thermal dispersion treatment.

[0078] The white pulp residue recovered from the paper mill wastewater treatment plant is output to the pulper 120 for pulping via the chain conveyor 110. After pulping, it is sent to the high-consistency desander 130 to remove heavy impurities and improve the cleanliness of the pulp. Then, it is sent to the unloading pulp tower 140. The unloading pump 150 then sends the pulp in the unloading pulp tower 140 to the low-consistency desander 160 to remove fine impurities. Finally, it is sent to the thermal dispersion system 170 to break down large particles of ink, adhesives, and other impurities in the pulp. This process reduces the impurities in the pulp and minimizes their harm to paper quality and paper machine operation. By treating the white pulp residue recovered from the paper mill wastewater treatment plant, it can replace domestic waste bleaching, optimize the process flow, and reduce raw material costs.

[0079] Please see Figure 2 In some embodiments, the thermal dispersion system 170 includes;

[0080] The pressing screw 210, with its inlet connected to the outlet of the low-concentration slag remover, is a device that uses the screw propulsion principle to mechanically dewater materials. It is widely used in industries such as papermaking, environmental protection, food processing, and chemicals. Its core function is to separate free water from the material through the rotation and extrusion of the screw shaft, achieving solid-liquid separation or concentration. The pressing screw 210 dewaters the pulp, increasing its concentration.

[0081] The feed plug screw 220 has its inlet connected to the outlet of the pressing screw 210. The feed plug screw 220 is a key piece of equipment in the thermal dispersion system 170, pulping and solid waste treatment. It is mainly used for the compression, sealing and conveying of high-concentration slurry to ensure stable system operation and prevent steam leakage.

[0082] The crushing screw 230 has its inlet connected to the outlet of the feed plug screw 220. The crushing screw 230 is a device that combines screw conveying and mechanical crushing functions, and is mainly used for crushing, conveying and pre-compressing high-concentration slurries.

[0083] Heating spiral 240, the inlet of which is connected to the outlet of crushing spiral 230; heating spiral 240 is an industrial device that integrates conveying, heating and mixing functions, and is used to uniformly heat high-concentration slurry.

[0084] The feeding screw 250 has its inlet connected to the outlet of the heating screw 240. The feeding screw 250 is a mechanical device for precise and continuous material conveying, which can stably convey the material heated by the heating screw 240 to the thermal disperser 260.

[0085] A thermal disperser 260 is provided, with its inlet connected to the outlet of the heating screw 240 and its outlet connected to the medium-fiber pulp storage tower 180. The thermal disperser 260 disperses impurities (such as adhesives, inks, and hot melts) in waste paper pulp into tiny particles through a triple action of mechanical shearing, friction, and heating. In this embodiment, a disc-type thermal disperser 260 is used; in other embodiments, a roller-type thermal disperser 260 or a single-shaft thermal disperser 260 may also be used.

[0086] Thermal dispersion is a process that uses high-temperature, high-concentration conditions to subject waste paper raw materials to high shearing. Through mechanical friction and inter-fiber friction, residual ink that has not been peeled off the fibers is removed, and large ink particles, adhesives, and other impurities in the pulp are fragmented. Thermal dispersion itself cannot remove impurities (although the white water in the concentration section does carry away some impurities, this is not its primary function). Its purpose is to ensure that the dispersed impurities are better removed in subsequent flotation or washing processes. Even those that cannot be removed are reduced in size, thus minimizing their harm to paper quality and paper machine operation: for example, ink particles smaller than 50µm are invisible to the naked eye and will not cause significant appearance quality problems. Specifically, the thermal dispersion system 170 concentrates the fed pulp through the press screw 210, then feeds it through the feed plug screw 220 to the crushing screw 230 for crushing, then feeds it through the heating screw 240 for heating, and finally feeds it through the feeding screw 250 into the thermal disperser 260 to disperse impurities in the pulp into tiny particles.

[0087] In some embodiments, the heating spiral 240 is a steam-heated spiral 240. A steam-heated spiral 240 is an industrial device that uses steam as a heat source to heat, convey, mix, or dehydrate materials. Through indirect steam heating, it achieves precise temperature control of the material while simultaneously completing conveying or processing. The steam-heated spiral 240 circulates steam through a jacket or the inner cavity of the spiral shaft, transferring heat to the slurry. The spiral blades propel the slurry forward, resulting in uniform heating. The temperature can be controlled by adjusting the steam pressure.

[0088] Please see Figure 3 In some embodiments, it also includes:

[0089] Flow meter 310 is installed on the slurry supply pipeline between the unloading slurry tower 140 and the medium fiber low concentration slag remover 160;

[0090] An automatic regulating valve 320 is connected to the flow meter 310 and is installed on the slurry supply pipeline between the unloading slurry tower 140 and the medium fiber low concentration slag remover 160.

[0091] To ensure a white pulp to medium fiber ratio of 1:8-9 in the slurry, a flow meter 310 and an automatic regulating valve 320 are installed in the slurry supply pipeline between the unloading slurry tower 140 and the medium fiber low-consistency desander 160. The flow meter 310 detects the slurry flow rate on the slurry supply pipeline between the unloading slurry tower 140 and the medium fiber low-consistency desander 160, and the automatic regulating valve 320 controls the slurry flow rate between the unloading slurry tower 140 and the medium fiber low-consistency desander 160 based on the slurry flow rate feedback from the flow meter 310, thereby controlling the ratio of white pulp to medium fiber.

[0092] In some embodiments, the chain conveyor 110, pulper 120, high-consistency desander 130, and unloading slurry tower 140 are the chain conveyor, pulper, high-consistency desander, and unloading slurry tower of a BKP line. The chain conveyor, pulper, high-consistency desander, and unloading slurry tower of the BKP line can be reused for pretreatment of white pulp residue recovered from paper recycling plants.

[0093] Please see Figure 4 In some embodiments, it also includes:

[0094] A lightweight impurity remover 410 is disposed between the low-consistency impurity remover 160 and the thermal dispersion system 170. The lightweight impurity remover 410 is a key piece of equipment in the waste paper pulping process, primarily used to remove lightweight impurities from the pulp, such as plastic film, wax, adhesives, and foam particles. Its working principle is based on eddy current centrifugal separation, utilizing the density difference between lightweight impurities and fibers to achieve efficient purification.

[0095] In some embodiments, the low-consistency desander 160, the light-weight desander 410, the thermal dispersion system 170, and the slurry storage tower 180 are the low-consistency desander, light-weight desander, thermal dispersion system, and slurry storage tower of the OCC medium-fiber system. The low-consistency desander, light-weight desander, thermal dispersion system, and slurry storage tower in the OCC medium-fiber system are used to remove light impurities such as adhesives and wax spots from the pretreated slurry.

[0096] Please see Figure 5 In some embodiments, it also includes:

[0097] A pulp pump 510 is provided, the inlet of which is connected to the pulp storage tower 180. The pulp pump 510 is used to feed the pulp in the pulp storage tower 180 into the paper machine mixing tank 520.

[0098] The treated pulp is fed into the paper machine mixing tank 520 by the pulp pump 510, and can then be used for the subsequent production of A3 grade kraft paper.

[0099] In some embodiments, a white pulp production system for A3 grade kraft paper is provided, the core innovation of which is to replace domestic waste white pulp with white pulp residue (brightness 50-55%, beating degree 15-25°SR) recovered from papermaking wastewater treatment plants, optimize the process flow, and achieve precise and rapid control of paper brightness and cost reduction.

[0100] The process includes:

[0101] White slurry residue pretreatment: The white slurry residue recovered from the sewage treatment plant is transported to the BKP line pulper 120 via the BKP line chain conveyor 110. Heavy impurities are removed by the high-consistency sludge remover 130 to improve the cleanliness of the slurry, and then it is sent to the BKP line unloading slurry tower 140.

[0102] Grading and Screening: The pulp is pumped to the OCC medium fiber system via the unloading tower, and sequentially passes through the low-consistency desander 160, the light-consistency desander 410, the thermal dispersion, and the medium fiber pulping tower before being directly added to the paper machine mixing tank 520. (Because the pulp is recycled from water treatment and has low cleanliness, if it were directly crushed and added to the paper machine mixing tank 520, it would cause quality problems such as impurities and wax spots on the paper surface. Therefore, it is mixed into the medium fiber system, where the medium fiber system equipment removes adhesives, wax spots, and other light impurities from the pulp.)

[0103] The white pulp residue recovered by the wastewater treatment plant refers to the white pulp residue obtained after the wastewater discharged from the company's pulping and papermaking workshops, which produce cultural paper, white cardboard, and household paper, has been treated by the wastewater treatment plant. The raw materials used in the production of cultural paper, white cardboard, and household paper are bleached wood pulp and bleached chemimechanical pulp.

[0104] Process parameter optimization:

[0105] (1) Control the ratio of white pulp to medium fiber at 1:8 to 9 (in order to achieve the desired ratio, a flow meter 310 and an automatic regulating valve 320 can be added to the pulp supply pipeline from the BKP unloading tower to the medium fiber system to control the pulp flow rate).

[0106] (2) The characteristic concentration of the slurry obtained after mixing treatment is 4.3-4.8%, the degree of freeness is 30-35°SR, the wet weight is 3.5-4.5g, and the pH value is 6-7.

[0107] (3) After the pulp is made, it is directly supplied to the surface mixing tank of the paper machine. The mixing tank uses 100% medium fiber pulp.

[0108] The purpose of thermal dispersion is to subject waste paper raw materials to high shearing under high temperature and high concentration conditions, and to remove residual ink that has not been peeled off from the fibers by means of mechanical friction and inter-fiber friction, and to break down large ink particles, adhesives and other impurities in the pulp.

[0109] Thermal dispersion itself cannot remove impurities (although the white water in the concentration section does carry away some impurities, this is not its primary task). Its purpose is to enable the dispersed impurities to be better removed in subsequent flotation or washing processes. Even the parts that cannot be removed will have reduced harm to paper quality and paper machine operation due to their smaller size: for example, ink particles smaller than 50um are invisible to the naked eye and will not cause obvious appearance quality problems.

[0110] Replacing domestic waste bleached pulp with recycled pulp residue from paper mill wastewater treatment plants can reduce raw material costs. Experimental data shows that when producing A3 grade kraft paper, using pulp residue to replace domestic waste bleached pulp can reduce raw material costs by about 2.2%, saving 35 yuan per ton of paper (calculated based on the average market price of domestic waste bleached pulp in 2025).

[0111] This also shortens the adjustment time. Previously, it took at least 3 hours for the results to be reflected from feeding material into the OCC pulper 120 to the paper machine mixing tank 520. This method bypasses the traditional OCC pulping system, shortening the process to approximately 30 minutes. During this process, data is displayed via online color scanning, allowing for real-time adjustment of the white pulp residue addition ratio to ensure the L value remains stable within the range of 57±1.

[0112] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A white pulp production system for A3 grade kraft paper, characterized in that, include: A chain conveyor, used to transport white slurry residue recovered from a wastewater treatment plant to a pulper; A pulper, which is used to pulp the white pulp residue conveyed by the chain conveyor and then send it to a high-consistency slag remover; A high-consistency slag remover is used to remove slag from the pulp fed into the pulper before sending it into the discharge slurry tower. The unloading slurry tower is used to store the slurry after the high-concentration slag remover has removed slag. A discharge pump is used to deliver slurry from the discharge slurry tower into a low-concentration slag remover. A low-concentration slag remover is used to remove slag from the slurry delivered by the unloading pump before sending it into the thermal dispersion system. A thermal dispersion system, wherein the thermal dispersion system is used to thermally disperse the slurry before feeding it into a medium fiber slurry storage tower; A slurry storage tower, used for storing slurry after thermal dispersion treatment.

2. The white pulp production system for A3 grade kraft paper according to claim 1, characterized in that, The thermal dispersion system includes; A pressing screw, the inlet of which is connected to the outlet of the low-concentration slag remover; A feed plug screw, wherein the feed inlet of the feed plug screw is connected to the discharge outlet of the pressing screw; A crushing spiral, wherein the feed inlet of the crushing spiral is connected to the discharge outlet of the feed plug spiral; A heating spiral, wherein the feed inlet of the heating spiral is connected to the discharge outlet of the crushing spiral; A feeding screw, wherein the inlet of the feeding screw is connected to the outlet of the heating screw; A thermal disperser, wherein the feed inlet of the thermal disperser is connected to the discharge outlet of the heating screw, and the discharge outlet of the thermal disperser is connected to the medium fiber slurry storage tower.

3. The white pulp production system for A3 grade kraft paper according to claim 2, characterized in that, The heating spiral is a steam-heating spiral.

4. The white pulp production system for A3 grade kraft paper according to claim 1, characterized in that, Also includes: A flow meter is installed on the slurry supply pipeline between the unloading slurry tower and the medium fiber low concentration slag remover. An automatic regulating valve is connected to the flow meter and is installed on the slurry supply pipeline between the unloading slurry tower and the medium fiber low concentration slag remover.

5. The white pulp production system for A3 grade kraft paper according to claim 1, characterized in that, The chain conveyor, pulper, high-consistency slag remover, and unloading slurry tower mentioned are the chain conveyor, pulper, high-consistency slag remover, and unloading slurry tower of the BKP line.

6. The white pulp production system for A3 grade kraft paper according to claim 1, characterized in that, Also includes: A lightweight slag remover is disposed between the low-concentration slag remover and the thermal dispersion system.

7. The white pulp production system for A3 grade kraft paper according to claim 6, characterized in that, The low-concentration slag remover, light-weight slag remover, thermal dispersion system, and slurry storage tower are the low-concentration slag remover, light-weight slag remover, thermal dispersion system, and slurry storage tower of the OCC medium fiber system.

8. The white pulp production system for A3 grade kraft paper according to claim 1, characterized in that, Also includes: A pulp pump, the inlet of which is connected to the pulp storage tower, is used to deliver the pulp in the pulp storage tower into the paper machine mixing tank.

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