Special paper production line installation method

Abstract

The invention relates to the technical field of specialty paper production, and discloses a specialty paper production line installation method which comprises the steps that equipment layout is conducted, specifically, equipment including a beating unit, a paper machine, a breast roll, a squeezing assembly, a drying cylinder, a sizing machine and a calender is linearly arranged according to an operation side plant column embedded part, and the beating unit is arranged at the feeding end of the paper machine and matched with a feeding port of the paper machine; the track gauge of a squeezing foundation plate between a fifth cantilever beam and a vacuum roller is 7400 mm, the track gauge of a drying part is 7200 mm, the track gauge of a sizing machine is 7260 mm, and the track gauge of a calender is 7300 mm; according to the piling method, based on equipment load distribution, concrete pile foundations are adopted for heavy load areas including a pressing part and a drying part, the pile depth is larger than or equal to 3 m, and the bearing capacity is larger than or equal to 1.5 times of the equipment dynamic load. By optimizing equipment layout and basic design and adapting to the characteristics of the bamboo fibers, industrial production of the bamboo fiber specialty paper is achieved, and the method has the advantages of environmental protection and cost.

Description

Technical Field

[0001] This invention relates to the field of specialty paper production technology, and more specifically to a method for installing a specialty paper production line. Background Technology

[0002] Specialty paper is widely used in food packaging, food bags, and paper straws, and its performance requirements are stringent, especially in terms of high cleanliness, strict microbial control, and excellent strength. Traditional specialty paper production primarily uses wood fiber as raw material, processed through pulping, forming, pressing, calendering, and sizing. However, with increasing environmental demands and growing awareness of forest resource protection, finding alternative raw materials to wood fiber has become an industry trend. Bamboo fiber, due to its short growth cycle, abundant resources, and environmental friendliness, has the potential to replace wood fiber. However, bamboo fiber has inherent defects such as being short, flat, and brittle; its fiber length and strength are lower than wood fiber, leading to difficulties in forming during traditional processing, easy breakage during pressing, and insufficient paper smoothness, making it difficult to meet the performance requirements of specialty paper.

[0003] Content and disadvantages of the current technical solution Currently, there are no mature precedents for using bamboo fiber to produce specialty paper. Traditional processes face the following core problems: 1. Fiber performance defects: Bamboo fibers are short and have low strength, and are easily cut during pulping, making it impossible to form an effective fiber interweaving network, resulting in the paper's tensile strength and bursting strength failing to meet standards.

[0004] 2. Forming and pressing challenges: Bamboo fiber has poor dispersion during the forming process in the headbox, which easily leads to pores or uneven thickness; during the pressing process, due to the high brittleness of the fiber, it is prone to crushing or breaking, resulting in a low yield.

[0005] 3. Insufficient surface quality: Traditional calendering processes cannot solve the problem of rough surface of bamboo fiber paper, making it difficult to meet the smoothness requirements of food packaging.

[0006] 4. Lack of hygiene control: The existing production line is not designed for food contact scenarios, the food-grade standards for equipment and paper contact parts are not clear, and microbial control is difficult.

[0007] In summary, given the environmental advantages of bamboo fiber and the gaps in existing technology, there is an urgent need to develop a special paper production line installation method tailored to the characteristics of bamboo fiber. Summary of the Invention

[0008] The present invention aims to provide a method for installing a specialty paper production line, so as to complete the installation of a bamboo fiber specialty paper production line with minimal cost and floor space, so that after the production line is installed, it can produce bamboo fiber specialty paper using natural bamboo.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A method for installing a specialty paper production line includes: Equipment Layout: The equipment, including the pulping unit, paper machine, breast roll, press roll, drying cylinder, sizing machine, and calender, is arranged linearly according to the embedded parts of the columns on the operating side of the plant. The pulping unit is located at the feed end of the paper machine and is adapted to the paper machine feed inlet. The paper machine is equipped with a headbox, and the center of the headbox outlet is coaxially aligned with the center of the pulp inlet of the paper machine forming section, with an axial deviation ≤ ±0.5mm and a horizontal height difference ≤ ±1mm. The headbox is precisely connected to the paper machine forming section. The track gauge between the fifth cantilever beam and the vacuum roll press base plate is 7400 mm, the track gauge of the drying section is 7200 mm, the track gauge of the sizing machine is 7260 mm, and the track gauge of the calender is 7300 mm. Piling method: Based on the equipment load distribution, concrete pile foundations are used for heavy load areas including the pressing section and drying section. The pile depth is ≥3 meters and the bearing capacity is ≥1.5 times the dynamic load of the equipment.

[0010] Beneficial effects: Precise track gauge design and load matching ensure stable equipment operation, optimize workshop space utilization, and meet the tension control requirements during bamboo fiber paper pressing and drying processes, reducing paper breakage caused by equipment vibration. Through reasonable size design and production line layout, the footprint can be minimized without affecting production line operation.

[0011] Preferably, the pulping unit is equipped with a bamboo fiber grading and screening device, which separates bamboo pulp fibers into long fibers and short fibers according to their length through a grading sieve, and prepares pulp separately; the length of the long fibers is greater than 1.5 mm, and the length of the short fibers is less than or equal to 1.5 mm; the graded pulp is transported to the headbox of the paper machine through pipelines.

[0012] Beneficial effects: Grading and screening can retain long fibers to enhance paper strength, while short fibers improve forming uniformity, solve the problem of insufficient interlacing force caused by uneven bamboo fiber length, and increase the tensile strength of paper by more than 20%.

[0013] Preferably, the production line is equipped with a bamboo pulp short fiber preparation line and a long fiber preparation line. The short fiber preparation line includes a double-disc refiner with a refinement concentration controlled at 5-8% and a freeness of 40-60°SR. The headbox of the paper machine is connected to the discharge port of the preparation line.

[0014] Beneficial effects: The double-disc refiner can separate bamboo fibers into bristles, improve fiber interweaving force, and accurately control the pulping degree to ensure that the paper uniformity qualification rate is ≥95%.

[0015] Preferably, the headbox forming temperature of the paper machine is controlled at 40-45℃.

[0016] Beneficial effects: It is 50 - 60 °C lower than the traditional process. Low-temperature wire drawing can slow down the fiber sedimentation speed, improve the dispersion uniformity of bamboo fibers, reduce the hole defects during forming, and the paper thickness deviation ≤ ±2%.

[0017] Preferably, the equipment components in the production line that come into contact with the paper, including the headbox, press rolls, and dryer cylinders, are all made of food-grade 316L stainless steel or food-grade coating materials.

[0018] Beneficial effects: Ensure the cleanliness of the paper contact surface, the total number of microbial colonies ≤ 100 CFU / g, meeting the food packaging hygiene standards.

[0019] Preferably, the calender is equipped with a four-roll replaceable press roll system, supporting the double-sided calendering process, and the line pressure of the press roll can be adjusted within the range of 10 - 100 N / mm.

[0020] Beneficial effects: Double-sided calendering can improve the surface roughness problem of bamboo fiber paper, the surface roughness Ra ≤ 3.0 μm. At the same time, the four-roll structure supports the switching of different calendering processes to meet the diverse product requirements.

[0021] Preferably, the sizing machine adopts a starch coating system, the sizing amount is controlled at 3 - 8 g / m², and the coating temperature is 60 - 80 °C.

[0022] Beneficial effects: Starch sizing can enhance the water resistance and strength of the paper, the folding endurance ≥ 100 times, and the tensile strength is increased by 15% - 25%, meeting the requirements of water-resistant scenarios such as paper straws.

[0023] Preferably, in the spray cooling system supporting the sizing machine, the inlet water temperature of the condenser is controlled at 35 - 40 °C, the flow rate is 200 - 250 L / min, the inlet water temperature of the cooling water is 15 - 30 °C, and the pressure ≤ 5 bar.

[0024] Beneficial effects: Precise temperature control ensures uniform curing of the sizing agent, avoids starch gelatinization failure, and the surface strength of the paper after sizing ≥ 2.0 mN.

[0025] Preferably, the drive form of the production line is AC variable frequency sectional drive, the working speed is 1000 m / min, the designed speed is 1100 m / min, and it supports double-machine synchronous calendering.

[0026] Beneficial effects: Double-machine synchronous calendering can reduce the single calendering time by more than 30%, improve the production efficiency, and at the same time ensure the consistency of the performance of both sides of the paper.

[0027] Preferably, the equipment foundation design considers the dynamic load coefficient: 2 - 3 times the static load for the press section, 1.5 times the static load for the drying section, and 2 times the static load for the reel section.

[0028] Beneficial effects: Improved vibration resistance of the basic structure, enhanced equipment operational stability, and reduced paper quality fluctuations caused by vibration.

[0029] The advantages of this invention are: 1. Environmental and cost advantages: Using bamboo fiber to replace wood fiber reduces raw material costs by 15%-20%, and bamboo has a short growth cycle (3-5 years), reducing the consumption of forest resources.

[0030] 2. Performance breakthrough: Solving the problem of insufficient strength of bamboo fiber, the tensile strength and bursting strength of the paper reach the level of wood fiber specialty paper, and some indicators (such as folding endurance) are improved by 10%-15%.

[0031] 3. Improved production efficiency: Dual-car synchronous calendering shortens processing time, with a car speed of up to 1000m / min and a nominal capacity of 467t / d (58g specification), which is 30% more efficient than traditional processes.

[0032] 4. Hygiene and Safety: Designed with all food-grade contact parts, strict microbial control, meeting FDA, GB4806.1 and other standards, suitable for direct food contact scenarios.

[0033] 5. Strong process adaptability: It can produce 30-90g / m² refined kraft paper with a roll width of 5660mm, supports switching between multiple specifications, and covers application scenarios such as food packaging and paper straws.

[0034] This invention compensates for the defects of bamboo fiber by optimizing equipment layout, process parameters and special technologies, and realizes the industrial production of bamboo fiber specialty paper, thus promoting the industry towards environmental protection and low cost. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the equipment layout and basic structure of the production line described in this invention. Detailed Implementation

[0036] The following detailed description illustrates the specific implementation method: Installation of bamboo fiber specialty paper production line: I. Equipment Layout and Track Gauge Setting On the operating side, the equipment is installed in the order of the embedded parts. Starting from the feed end, the pulping unit, headbox, paper machine, and breast roll are arranged in sequence. The pulping unit is fixed to the equipment foundation on the left side of the paper machine feed inlet by a bracket. The headbox is located between the pulping unit and the paper machine. Its feed inlet and the pulping unit outlet are sealed together by a flange. The center of the outlet is coaxially aligned with the center of the pulp inlet of the forming section of the paper machine. The axial deviation is controlled within ±0.5mm, and the horizontal height difference does not exceed ±1mm. The track gauge between the breast roll and the first cantilever beam to the fifth cantilever beam is maintained at 7400 mm to ensure the installation accuracy of the press section (vacuum roll and press roll). The track gauge of the section from the first Vac cylinder to the fifth drying cylinder is adjusted to 7200 mm, the drying cylinder spacing is 1.2 meters, and 9 sets of Vac cylinders are configured (vacuum degree -0.06 to -0.08 MPa). The sizing machine (lower roller diameter 800mm, upper roller diameter 1000mm) has a track gauge of 7260mm, and the calender (four-roller structure, top roller hardness 85° Shore A) has a track gauge of 7300mm.

[0037] Piling and foundation construction 2. The foundation of the pressing section adopts C30 concrete piles with a pile diameter of 600mm and a pile depth of 3.5 meters. The single pile bearing capacity is ≥500kN (dynamic load is calculated based on 3 times the static load). The drying section is equipped with shock-absorbing pads, 50mm thick, made of neoprene rubber, to reduce vibration transmission.

[0038] III. Bamboo Fiber Grading, Screening, and Pulping The bamboo pulp is separated into long fibers (30% of the total, 3-7mm in length) and short fibers (70% of the total, ≤2mm in length) by a grading sieve (0.2mm mesh). The short fiber pulp was processed by a double-disc refiner (disc gap 0.1mm), with a refinement concentration of 5%, a freeness of 55°SR, and a wet weight of 6g.

[0039] IV. Headbox and Molding Control The headbox temperature is 40-45℃, the pulp concentration is 0.2-0.35%, and the headbox pressure is 5kPa to ensure uniform dispersion of bamboo fibers. After forming, the paper basis weight is 58g / m² and the thickness is 110μm.

[0040] V. Calendering and Sizing The linear pressure of the dual-zone soft calender is first adjusted to 50 N / mm (first zone), then to 80 N / mm (second zone), and the surface smoothness is achieved after calendering for 50 seconds. The sizing machine is coated with a 5% starch solution, the sizing amount is 3g / m², the drying cylinder temperature is 120℃ for curing, and the paper's bursting strength is ≥850kPa.

[0041] VI. Performance Parameters The finished product has a quantitative weight of 58g / m², tensile strength MD47.28N / cm, CD38.44N / cm, tear strength MD6.23N, and total microbial count of 80CFU / g, meeting food packaging standards.

[0042] Compared to existing technologies, this invention is non-obvious: Current technology fails to recognize that bamboo fiber defects can be addressed through a combined process of "grading and screening + low-temperature molding + dual-wheel calendering": Grading and screening retain long fibers to enhance strength, overcoming the inherent limitation of short bamboo fibers (traditionally believed that short fibers cannot be used in specialty paper). The synergistic design of low-temperature wire bonding (0.2℃) and four-roll calendering solves the problems of poor bamboo fiber dispersion and surface roughness. This temperature parameter and equipment configuration are not conventional choices in this field. The variable gauge design (7400 / 7200 / 7260mm) is optimized for the tension characteristics of bamboo fiber paper, rather than simply adopting the standard of wood fiber production line.

[0043] Traditional views hold that bamboo fiber cannot meet the strength requirements of specialty paper. This invention achieves the first industrial production of bamboo fiber specialty paper through multi-dimensional innovations in equipment layout (such as widening the gauge of the press section), process parameters (such as precise control of beating degree), and material upgrades (food-grade components). Its technical solution is not a simple improvement of existing technologies, but a systematic breakthrough targeting the characteristics of bamboo fiber.

[0044] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for installing a special paper production line, characterized in that, Including: Equipment layout: Equipment including a slurrying unit, a paper machine, a breast roll, a press roll, a dryer, a sizing machine, and a calender is linearly arranged according to the embedded parts of the plant columns on the operating side. The slurrying unit is arranged at the feeding end of the paper machine and is adapted to the feeding port of the paper machine. A headbox is provided for the paper machine, and the center of the discharging port of the headbox is coaxially aligned with the center of the pulp inlet of the forming section of the paper machine, with an axial deviation ≤ ±0.5 mm and a horizontal height difference ≤ ±1 mm. A headbox is provided for the paper machine, and the headbox is accurately docked with the forming section of the paper machine. The track gauge between the fifth cantilever beam and the vacuum roll press base plate is 7,400 mm, the track gauge of the dryer section is 7,200 mm, the track gauge of the sizing machine is 7,260 mm, and the track gauge of the calender is 7,300 mm. Piling method: Based on the equipment load distribution, a concrete pile foundation is adopted for heavy load areas including the press section and the dryer section, with a pile depth ≥ 3 m and a bearing capacity ≥ 1.5 times the dynamic load of the equipment.

2. The installation method for a special paper production line according to claim 1, characterized in that, A bamboo fiber grading and screening device is arranged in the slurrying unit. The bamboo pulp fibers are divided into long fibers and short fibers by a grading screen, and slurries are prepared separately. The length of the long fibers is greater than 1.5 mm, and the length of the short fibers is less than or equal to 1.5 mm. The graded slurries are transported to the headbox supporting the paper machine through pipelines.

3. The installation method for a special paper production line according to claim 2, characterized in that, The production line is equipped with a bamboo pulp short fiber stock preparation line and a long fiber stock preparation line. The short fiber stock preparation line includes a double-disc refiner, and the refining concentration is controlled at 5-8%, and the beating degree is 40-60°SR. The headbox supporting the paper machine is connected to the discharging port of the stock preparation line.

4. The installation method for a special paper production line according to claim 1, characterized in that, The forming and web-forming temperature of the headbox supporting the paper machine is controlled at 40-45°C.

5. The installation method for a special paper production line according to claim 1, characterized in that, Equipment components in the production line that come into contact with the paper, including the headbox, press roll, and dryer, are all made of food-grade 316L stainless steel or food-grade coating materials.

6. The installation method for a special paper production line according to claim 1, characterized in that, The calender is equipped with a four-roll replaceable press roll system, supporting a double-sided calendering process, and the line pressure of the press roll is adjustable within the range of 10-100 N / mm.

7. The installation method for a special paper production line according to claim 1, characterized in that, The sizing machine adopts a starch coating system, and the sizing amount is controlled at 3-8 g / m², and the coating temperature is 60-80°C.

8. The installation method for a special paper production line according to claim 7, characterized in that, In the spray cooling system supporting the sizing machine, the inlet water temperature of the condenser is controlled at 35-40°C, the flow rate is 200-250 L / min, the inlet water temperature of the cooling water is 15-30°C, and the pressure ≤ 5 bar.

9. The installation method for a special paper production line according to claim 1, characterized in that, The transmission form of the production line is AC variable-frequency sectional drive, with an operating speed of 1,000 m / min and a designed speed of 1,100 m / min, supporting double-machine synchronous calendering.

10. The installation method for a special paper production line according to claim 1, characterized in that, The equipment foundation design takes into account the dynamic load coefficient: 2-3 times the static load for the press section, 1.5 times the static load for the dryer section, and 2 times the static load for the reel section.

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