Plant fiber preparation system

Abstract

The plant fiber preparation system comprises a pipeline presoaking section, a thread rolling section, a transverse pipe cooking reaction section, a high-concentration pressure pulping machine section, a high-concentration bleaching section, a pulp washing section, a low-concentration grinding section and a screening section which are connected in sequence. The pipeline preimpregnation section is formed by connecting a plurality of spiral pipelines, each spiral pipeline comprises a dosing port and a steam port, and the plurality of spiral pipelines form a closed body. By improving a traditional fiber production line and a production process, the prepared semi-bleached pulp can replace a traditional high-cost long fiber raw material to be used for producing medium-grade and high-grade paper for daily use, and the product cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of plant fiber processing, relates to plant fiber preparation technology, and particularly relates to a plant fiber preparation system. Background Art

[0002] Papermaking fiber raw materials are the basic components of paper. They include plant fibers, mineral fibers, and synthetic fibers. The choice of fiber raw materials depends primarily on paper quality requirements, production conditions, and regional resource availability. The vast majority of fiber raw materials used in the papermaking industry are plant fibers.

[0003] The tubular or spindle-shaped cells in plants are called fibers in papermaking technology. Plants used as fiber raw materials for the papermaking industry should have the following conditions: high fiber content, sufficient resources, convenient transportation and reasonable manufacturing costs. Plant fiber raw materials are generally divided into two categories: wood and non-wood fiber raw materials. In the existing process of using plant fibers to prepare paper, the length of the plant fibers directly affects the quality of the final manufactured product. Although the quality of the finished product is good, the cost is high when using plant pulp made from wood. Native plants need to be used as raw materials, and the need to cut down wood violates the concept of environmental protection. Papermaking using fiber raw materials obtained from secondary recycling has plant fibers that are generally short in length and uneven in length, which makes the fiber cost complicated and the quality of the manufactured product low. Summary of the Invention

[0004] In view of the above-mentioned defects in the prior art, the present invention discloses a plant fiber preparation system.

[0005] The plant fiber preparation system of the present invention comprises a pipeline prepreg section, a thread rolling section, a transverse tube cooking reaction section, a high-concentration pressure pulping machine section, a high-concentration bleaching section, a pulp washing section, a low-concentration grinding section and a screening section which are connected in sequence.

[0006] Preferably, the pipeline prepreg section is composed of a plurality of spiral pipelines connected together, wherein the spiral pipelines include a dosing port and a steam port, and the plurality of spiral pipelines form a closed body.

[0007] Preferably, the high-concentration pressure refiner section comprises a high-concentration pressure refiner, a blowdown pipe and a slurry blowdown bin connected in sequence, and a drug adding point is provided on the blowdown pipe.

[0008] Preferably, the pulp washing section is a double-roll pulp washer.

[0009] Preferably, the screening section comprises a plurality of pressure screens and desanders connected in sequence.

[0010] Preferably, the plant fiber preparation system further comprises a material preparation section located before the pipeline prepreg section, and the material preparation section comprises preliminary processing equipment and a small buffer silo.

[0011] Preferably, the plant fiber preparation system further comprises a double-wire pulping and storage section located after the screening section: the double-wire pulping and storage section comprises a double-wire pulping machine and a baling machine.

[0012] The present invention improves the traditional fiber production line and production process, and the semi-bleached pulp prepared can replace the traditional long fiber raw materials with higher costs for producing medium and high-grade household paper, thereby reducing product costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic structural diagram of a specific implementation of the plant fiber preparation system of the present invention. DETAILED DESCRIPTION

[0014] In order to more intuitively and clearly describe the specific details of the technical solution of the present invention, a detailed description will be given below in conjunction with specific embodiments and example drawings.

[0015] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely explained below in conjunction with the specific embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] The plant fiber preparation system of the present invention includes the following working sections: Preparation section: In the preparation section, the raw materials are screened, crushed, washed and processed to reach the qualified raw material form before being stored in the buffer silo. The specific size and raw material screening conditions are determined by the product requirements and the specific process.

[0017] For example, for bamboo raw materials, choose bamboo raw materials with smooth surface and no insect pests and diseases, cut into bamboo sticks with a length of 7-60 mm and a width of about 3-5 mm. The raw materials should be dried until the moisture content is less than 55%, and then washed and sent to a small buffer silo for storage.

[0018] The pipeline prepreg section is composed of multiple spiral pipelines connected together, and the multiple spiral pipelines include a dosing port and a steam port, which can add alkali solution and steam from the outside; the multiple spiral pipelines form a closed body, and when prepregging, each section of the spiral pipeline controls the type and amount of internal alkali solution, and adjusts the internal temperature by the steam supply speed, and controls the time required for the prepreg process by the forward speed of the raw materials in the prepreg section.

[0019] During the pre-preg stage, the alkali solution is added at a mass ratio of 1.25-4:1 to the feed material. The alkali solution is made from 5-8% sodium carbonate by mass mixed with water. The temperature in the pre-preg stage is 90-95°C, and the feed material is passed through for 60-75 minutes. By setting appropriate alkali dosage, liquid ratio, temperature, and time, the bamboo fiber is softened, making it easier to handle in subsequent steps, reducing energy consumption, and improving product quality.

[0020] Steam heating pre-impregnation is carried out through the pre-impregnation section of the pipeline to pre-impregnate and soften the plant fiber raw materials. Compared with traditional room temperature pre-impregnation and pre-cooking, it is more efficient, energy-saving and environmentally friendly.

[0021] Thread rolling section: A twin-screw fiber thread rolling machine is used. The equipment is connected to the pipeline prepreg section in front and the transverse steam reactor in the back. Its main function is to use strong mechanical action to make the softened plant fiber sheets into toothpick-shaped fiber bundles with a width of 1-3 mm, laying the foundation for the next step of processing. The processing effect of the twin-screw fiber thread rolling machine is better than that of the tearing machine.

[0022] The horizontal tube cooking reaction section, the horizontal tube cooking reactor is also called the modern Pandya continuous digester. In the horizontal tube cooking reaction section, the mass ratio of the added alkali solution to the feed is 2-35:1; the alkali solution is made of 20-35% by mass of sodium carbonate and water. The temperature in the horizontal tube cooking reaction section is 130-148°C, the pressure is pumped to a negative pressure of 0.3-0.5 MPa, and the cooking time is 30-45 minutes.

[0023] The present invention utilizes the cooking function to further process the rolled fibers under special process conditions, appropriately removes lignin and other easily removable organic matter, softens the fiber bundles and ensures that the fibers are not damaged.

[0024] The traditional chemical-mechanical pulp reactor does not have this function. At the same time, the traditional semi-chemical pulp cooking conditions are high temperature, high pressure, and high alkali, which make the cooking conditions severe, the pulp yield low, the energy consumption high, and even damage the fiber quality. Too much is as bad as too little.

[0025] This invention innovatively utilizes a horizontal tube digester to control the cooking temperature, pressure, and time, and appropriately adjust the alkali dosage to achieve excellent results. High-yield semi-chemical pulp, chemical-mechanical pulp, semi-bleached pulp, and fully bleached pulp can be produced. By varying process conditions and operating requirements, different pulp products suitable for different markets can be produced.

[0026] High-consistency pressure refiner section: A high-consistency pressure refiner is used for pulping. The fiber material treated in the previous process is input into the refiner. Under appropriate temperature and pressure, the fibers are rubbed vigorously and silkened into single fibers.

[0027] The high-consistency pressure pulping machine is an existing technology. A specific parameter setting method is: gap 20-40 silk, beating degree: 18-20°SR. Concentration 25-30%, temperature 130-150℃, pressure 0.3-0.5MPa, time 3-20 minutes, and the wet weight of a single fiber after silking is greater than 5-6g.

[0028] The use of high-concentration grinding has little effect on fiber shearing, thus protecting the fiber length to the greatest extent.

[0029] Under the pressure of the refiner, the slurry is sent to the slurry spray bin through the high-concentration spray pipe connected to the grinding chamber for pressure relief and discharge. There is a drug addition point on the spray pipe, and different chemicals are added according to different product needs.

[0030] For example, for semi-bleached bamboo pulp, the following chemicals are added to the blowpipe: hydrogen peroxide 6-8%, chelating agent 0.3%, stabilizer (0.7%, magnesium sulfate 0.3%, alkali 2-3%. The above percentages are all proportional to the mass of the raw materials. For example, for 100 kg of raw materials, 6-8 kg of hydrogen peroxide is added. The chelating agent can be DTPMPA (pentaamine methane pentaphosphate).

[0031] High-consistency bleaching section: The high-consistency bleaching tower is the key equipment in this section. The slurry sprayed from the slurry spraying bin is sent to the high-consistency bleaching tower. After certain bleaching reaction conditions, it is transformed from high-consistency to medium-consistency under the action of the tower bottom unloader and is sent to the subsequent production section by the medium-consistency pump.

[0032] The high-concentration bleaching stage requires specific bleaching reaction conditions and process parameters. Specific reaction process parameters for a high-concentration bleaching tower include a pH of 9.5-10 and a temperature of 85-90°C. The midpoint pH of the reaction is 8.5-9.5, residual oxygen after the reaction is less than 0.1%, and the slurry concentration, i.e., the solids content in the slurry, is reduced to 18-25%.

[0033] Washing: A twin-roller washer performs medium-consistency and low-consistency washing, removing high-concentration COD (chemical oxygen demand) solutions exceeding 80 mg / L for separate treatment. The relatively clean medium- and low-concentration COD slurries proceed to the next stage.

[0034] The double-roll pulp washer is a commonly used pulp washing equipment. Its working principle is extrusion displacement washing. The high-concentration waste liquid in the pulp is removed by double-roll extrusion and the residual high-concentration liquid is replaced by cleaner water, thereby achieving the purpose of pulp washing.

[0035] Low-concentration grinding section: The low-concentration refiner performs low-concentration refining treatment to obtain fiber-containing pulp according to different raw materials and customer product requirements.

[0036] The low-consistency refiner is an existing equipment. The kneading and shearing action of the refiner's discs further separates the fiber bundles and evens out the fiber thickness and length, making the physical form of the pulp more uniform. The temporary storage tower and post-grinding pulp tank are used for storage, while also playing a role in de-latching and swelling the fibers during storage.

[0037] Screening section: pressure screen and desander are key equipment in this section. After being purified by several sections of screens and desanders, qualified slurry enters the next section.

[0038] Pressure screens and desanders are conventional chemical physical separation equipment. They separate different materials by setting the fluid flow path of the equipment, using pressure, velocity and the difference in specific gravity between the materials.

[0039] Double-wire pulping and storage section: The double-wire pulping machine and baling machine are key equipment in this section. Qualified pulp is squeezed through the double-wire multi-stage extrusion to obtain semi-dry pulp with appropriate dryness and then packaged and stored. Loose pulp can also be stored. At the same time, the double-wire pulping machine also has an efficient pulp washing function to further improve the pulp cleanliness and meet product quality requirements.

[0040] In summary, the present invention improves the traditional fiber production line and production process, and the semi-bleached pulp prepared can replace the traditional long fiber raw materials with higher costs for the production of medium and high-grade household paper, thereby reducing product costs.

[0041] The foregoing are various preferred embodiments of the present invention. Unless the preferred implementation modes in each preferred embodiment are obviously self-contradictory or based on a certain preferred implementation mode, each preferred implementation mode can be arbitrarily superimposed and used in combination. The embodiments and specific parameters in the embodiments are only for the purpose of clearly describing the inventor's invention verification process, and are not intended to limit the patent protection scope of the present invention. The patent protection scope of the present invention shall still be based on its claims. Any equivalent structural changes made using the contents of the description of the present invention should also be included in the protection scope of the present invention.

Claims

1. A plant fiber preparation system, characterized in that: It includes a pipeline pre-preg section, a thread rolling section, a horizontal tube cooking reaction section, a high-consistency pressure refiner section, a high-consistency bleaching section, a pulp washing section, a low-consistency grinding section and a screening section that are connected in sequence.

2. The plant fiber preparation system according to claim 1, wherein: The pipeline prepreg section is composed of a plurality of spiral pipelines connected together. The spiral pipelines include a dosing port and a steam port. The plurality of spiral pipelines form a closed body.

3. The plant fiber preparation system according to claim 1, wherein: The high-consistency pressure refiner section comprises a high-consistency pressure refiner, a spraying pipe and a slurry spraying bin which are connected in sequence, and a drug adding point is provided on the spraying pipe.

4. The plant fiber preparation system according to claim 1, wherein: The pulp washing section is a double-roll pulp washer.

5. The plant fiber preparation system according to claim 1, wherein: The screening section includes a plurality of pressure screens and desanders connected in sequence.

6. The plant fiber preparation system according to claim 1, wherein: The plant fiber preparation system further comprises a material preparation section located before the pipeline prepreg section, and the material preparation section comprises preliminary processing equipment and a small buffer silo.

7. The plant fiber preparation system according to claim 1, wherein: The plant fiber preparation system further comprises a double-wire pulping and storage section located after the screening section: the double-wire pulping and storage section comprises a double-wire pulping machine and a baling machine.

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