Stone roller anti-sticking control method for acid papermaking system of high-speed paper machine

Abstract

The invention provides a stone roller anti-sticking control method for an acid papermaking system of a high-speed paper machine. The method comprises the following steps: adding cationic starch and an amphoteric dry strength agent into a paper pulp system to reduce anionic garbage in the paper pulp system; carrying out internal sizing by using a foam-inhibiting fortified rosin sizing agent; and spraying the alcohol-free dissolving type stripping agent on the surface of the stone roller through a spraying device. The stone roller anti-sticking control method for the acid papermaking system of the high-speed paper machine, provided by the embodiment of the invention, is high in comprehensiveness and remarkable in effect: through triple synergistic effects of'in-pulp (anion garbage control)-process (foam-inhibiting rosin sizing)-terminal (alcohol-free stripping agent) ', generation and deposition of viscous substances are reduced from the source, and the quality of the stone roller is improved. The problem of material sticking of the stone roller under high-speed acidic papermaking is thoroughly solved, and the operation efficiency is improved; the control method has the characteristics of being adaptive to a closed system, capable of improving paper quality and high in cost effectiveness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of papermaking, in particular to a control method for preventing material sticking to a stone roll in an acid papermaking system of a high-speed paper machine. BACKGROUND

[0002] In an acid papermaking system of a high-speed paper machine (vehicle speed > 1400 m / min), the application of a rosin-aluminum sulfate sizing system often leads to a serious material sticking problem of the three-press stone roll in the calendering section. The material sticking can cause holes, black spots and other paper defects on the paper surface, and frequent shutdown for cleaning seriously affects the production efficiency and product quality.

[0003] After analyzing the material sticking, it is found that the main components of the material sticking are organic matter and inorganic salt. The organic matter is carboxylate and sulfate, which comes from sticky substances such as rosin sizing agent in the pulp. The inorganic salt is talc and silicate, which comes from other inorganic fillers.

[0004] The existing technology mainly uses a method of spraying a release agent to solve this problem. However, in a closed-loop papermaking system, the traditional release agent containing alcohol (such as ethanol and isopropyl alcohol) has a significant defect: alcohol substances are easy to migrate to the wire section with water circulation, interfere with the rosin sizing process, and in severe cases, can cause the anti-lactic acid (lactic acid resistance for food packaging paper) edge to be ineffective, directly affecting the application performance of the final product. In addition, the closed system has higher requirements for the compatibility and stability of chemicals, and a single end treatment method often has limited effect. SUMMARY

[0005] The embodiments of the present application provide a control method for preventing material sticking to a stone roll in an acid papermaking system of a high-speed paper machine, which comprises: adding cationic starch and amphoteric dry strength agent in the pulp system to reduce anionic trash in the pulp system; using a foam-suppressed reinforced rosin sizing agent for in-pulp sizing; spraying a non-alcohol dissolving type release agent on the surface of the stone roll through a spraying device.

[0006] In some optional embodiments, the step of adding cationic starch and amphoteric dry strength agent in the pulp system to reduce anionic trash in the pulp system further comprises adding dry powder flow aid and silica sol in the later stage to further retain the anionic trash in the system in the paper.

[0007] In some optional embodiments, the papermaking base paper comprises a surface layer, a core layer and a bottom layer, wherein the chemical agent of the surface layer comprises: 10-20 kg / t of pulp of cationic dispersed rosin, 10-20 kg / t of pulp of aluminum sulfate solution, and 0-100 g / t of pulp of retention aid.

[0008] In some alternative embodiments, the chemicals for the core layer include: talcum powder in an amount of 100-200 kg / t of pulp, cationic starch in an amount of 15-25 kg / t of pulp, dry strength agent in an amount of 10-20 kg / t of pulp, cationic dispersed rosin in an amount of 10-20 kg / t of pulp, aluminum sulfate solution in an amount of 10-20 kg / t of pulp, dry powder retention aid in an amount of 0-100 g / t of pulp, and silica sol in an amount of 2-5 kg / t.

[0009] In some alternative embodiments, the chemicals for the bottom layer include: cationic dispersed rosin in an amount of 10-20 kg / t of pulp, aluminum sulfate solution in an amount of 10-20 kg / t of pulp, retention aid in an amount of 250-350 g / t of pulp, purple dye in an amount of 0-20 g / t of pulp, and blue dye in an amount of 50-100 g / t of pulp.

[0010] In some alternative embodiments, the step of using the foam-suppressing type of reinforced rosin sizing agent for in-pulp sizing includes the sizing agent comprising maleic anhydride modified petroleum resin, rosin, and foam suppressor.

[0011] In some alternative embodiments, the sizing agent is used in an amount of 10-25 kg per ton of paper, the aluminum sulfate is used in an amount of 1.5-2.5 times the amount of the sizing agent, and the pH value of the pulp on the wire is controlled to be between 4.8 and 5.5.

[0012] In some alternative embodiments, the step of spraying the non-alcohol dissolving type of release agent on the surface of the stone roll by the spraying device includes the non-alcohol dissolving type of release agent comprising, by mass percentage, 80%-85% of isomeric alkanes and 15%-20% of oleic acid polyethylene glycol ester.

[0013] In some alternative embodiments, the spraying amount of the non-alcohol dissolving type of release agent is 50-80 mL / min / m, the spraying water pressure is 8-15 pounds, and the spraying position is the inlet side of the three-pressure stone roll.

[0014] In some alternative embodiments, the control method is used for an acidic papermaking closed system of a high-speed paper machine with a speed of ≥1400 meters / min.

[0015] The method for controlling stone roll anti-sticking material in high-speed paper machine acidic papermaking systems provided in this application has the following characteristics: First, it is comprehensive and effective: through the triple synergistic effect of "in-slurry (anionic waste control) - process (antifoaming rosin sizing) - terminal (alcohol-free stripping agent)," it reduces the generation and deposition of sticky substances from the root, completely solving the problem of stone roll sticking material under high-speed acidic papermaking and improving operating efficiency; before adding chemical agents, the anionic PCD range in the system is -100μeq / L to -300μeq / L; after adding cationic starch and dry strength agent, the pulp PCD is -20μeq / L to -40μeq / L; after further adding talc, aluminum sulfate, rosin, dry powder retention aid, and silica sol, the pulp PCD is -10μeq / L to +10μeq / L; it is adaptable to closed systems. System: The core alcohol-free silicone stripper formula completely avoids interference from alcohol chemicals on the front-end rosin sizing, ensuring the stability of lactic acid edge seepage resistance in high-end paper types such as food packaging paper, and is particularly suitable for closed water circulation systems; Improved paper quality: The use of anionic debris traps in the anti-foaming sizing agent, cationic starch, and amphoteric dry strength agent improves the retention of various types of colloids and particles in the system, optimizes the wet-end chemical environment, and the synergistic effect of cationic starch and amphoteric dry strength agent increases the zeta potential of the pulp from -35V to -25V to -5V to +5V, which not only reduces roller sticking but also improves sizing degree and paper uniformity, thus improving overall product quality; High cost-effectiveness: Precise chemical addition and spray control avoid overuse, reduce overall costs, and reduce downtime losses caused by sticking. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart of an embodiment of the method for controlling anti-sticking material on stone rolls in a high-speed paper machine acidic papermaking system. Figure 2 This is a schematic diagram of the laminated structure of one embodiment of the original paper of this application; Figure 3 This is a schematic diagram of the drug addition point flow of the core laminar flow delivery system of this application; Figure 4 This is a schematic diagram of the structure of the spraying position of the alcohol-free solvent-based stripper in the embodiments of this application. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the invention. Similarly, the following embodiments are only some, not all, embodiments of the present invention, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The terms "first," "second," and "third" used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movement of components in a specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] This application provides a comprehensive process that allows for full control from the source to the end, effectively preventing material from sticking to the stone rollers, fully adapting to the special requirements of high-speed, closed, acidic papermaking systems, and without affecting the key performance indicators of the paper.

[0022] Please see Figure 1 , Figure 1This is a flowchart illustrating an embodiment of a method for controlling the anti-sticking material on stone rolls in a high-speed paper machine acidic papermaking system, which includes, but is not limited to, the following steps. It should be noted that this application's embodiments only focus on and describe in detail the steps and technical points related to the anti-sticking material on stone rolls. Other steps in the papermaking system that are unrelated to the inventive points of this application will not be described in detail here, to the understanding of those skilled in the art.

[0023] Step S100: Add cationic starch and amphoteric dry strength agent to the pulp system to reduce anionic waste in the pulp system.

[0024] First, it should be noted that the control method in the embodiments of this application is used for a high-speed paper machine acidic papermaking closed system with a machine speed ≥1400 m / min (generally in the range of about 1400 m / min to 1500 m / min).

[0025] In this step, cationic starch and amphoteric dry strength agent (which is cationic) are added to the pulp. In addition to enhancing the strength of the paper, cationic starch and amphoteric dry strength agent can also act as anionic waste capture agents in the system. In the later stage, dry powder flow aid (specifically cationic polyacrylamide) and silica (silica sol) are added to further retain various anionic wastes in the system in the sheet, thereby improving the cleanliness of the system.

[0026] Optionally, please refer to Figure 2 , Figure 2 This is a schematic diagram of the laminated structure of a base paper according to an embodiment of this application. The base paper in this embodiment may include a surface layer 110, a core layer 120, and a bottom layer 130. The chemicals in the surface layer 110 may include: cationic dispersed rosin at a dosage of 10-20 kg / t pulp, specifically 10 kg / t pulp, 12 kg / t pulp, 15 kg / t pulp, 18 kg / t pulp, 20 kg / t pulp, etc.; aluminum sulfate solution at a dosage of 10-20 kg / t pulp; and retention aid 0-100 g / t pulp. The effective content of the aluminum sulfate solution is ≥7.5%.

[0027] Optionally, please refer to Figure 3 , Figure 3This is a schematic diagram of the chemical addition point of the core layer flow system of this application. The chemicals in the core layer 120 include: talc powder at a dosage of 100-200 kg / t slurry; cationic starch at a dosage of 15-25 kg / t slurry (specifically, values ​​such as 15 kg / t slurry, 18 kg / t slurry, 20 kg / t slurry, 22 kg / t slurry, 25 kg / t slurry, etc.); dry strength agent at a dosage of 10-20 kg / t slurry (specifically, values ​​such as 10 kg / t slurry, 12 kg / t slurry, 15 kg / t slurry, 18 kg / t slurry, 20 kg / t slurry, etc.); and cationic dispersed rosin ...). The dosage of slurry is calculated as follows: 10 kg / t slurry, 12 kg / t slurry, 15 kg / t slurry, 18 kg / t slurry, 20 kg / t slurry, etc.; aluminum sulfate solution dosage is 10-20 kg / t slurry, specifically 10 kg / t slurry, 12 kg / t slurry, 15 kg / t slurry, 18 kg / t slurry, 20 kg / t slurry, etc.; dry powder retention aid dosage is 0-100 g / t slurry, specifically 1 g / t slurry, 10 g / t slurry, 20 g / t slurry, 50 g / t slurry, 60 g / t slurry, 80 g / t slurry, 100 g / t slurry, etc.; silica sol dosage is 2-5 kg / t, specifically 2 kg / t, 2.5 kg / t, 3 kg / t, 4 kg / t, 5 kg / t, etc.

[0028] The chemical agents in the bottom layer 130 include: cationic dispersed rosin at a dosage of 10-20 kg / t slurry, specifically 10 kg / t slurry, 12 kg / t slurry, 15 kg / t slurry, 18 kg / t slurry, 20 kg / t slurry, etc.; aluminum sulfate solution at a dosage of 10-20 kg / t slurry, specifically 10 kg / t slurry, 12 kg / t slurry, 15 kg / t slurry, 18 kg / t slurry, 20 kg / t slurry, etc.; retention aid at 250-350 g / t slurry; purple dye at a dosage of 0-20 g / t slurry; and blue dye at a dosage of 50-100 g / t slurry.

[0029] Please continue reading. Figure 1 The control method in this application embodiment further includes step S200, which involves using a foam-suppressing and reinforcing rosin sizing agent for in-slurry sizing.

[0030] In step S200, the sizing agent includes maleic anhydride-modified petroleum resin, rosin, and foam inhibitor. The dosage of the sizing agent is 10-25 kg / ton of paper, and the dosage of aluminum sulfate is 1.5-2.5 times the dosage of the sizing agent. The pH value of the online pulp is controlled between 4.8 and 5.5.

[0031] Please continue reading. Figure 1 The control method in this embodiment further includes step S300, which involves spraying an alcohol-free solvent stripper onto the surface of the stone roller using a spraying device.

[0032] In this step, the alcohol-free dissolving stripper comprises, by mass percentage, 80%–85% isoalkanes (providing excellent solubility and chemical stability) and 15%–20% oleic acid polyethylene glycol ester (acting as an emulsion stabilizer, exhibiting good emulsifying, wetting, and dispersing properties). Optionally, the mass ratio of isoalkanes to oleic acid polyethylene glycol ester can be specific values ​​such as 15:85, 16:84, 18:82, 19:81, 20:80, etc.

[0033] The spraying rate for the alcohol-free solvent-based stripper is 50-80 mL / min / m (width), specifically 50 mL / min / m, 60 mL / min / m, 65 mL / min / m, 70 mL / min / m, 80 mL / min / m, etc. The spraying water pressure is 8-15 psi; for example, 8 psi, 8.5 psi, 9 psi, 9.1 psi, 10 psi, 10.5 psi, 11 psi, 12 psi, 15 psi, etc. The spraying location is the inlet side of the three-pressure stone roller. Please refer to [link / reference]. Figure 4 , Figure 4 This is a schematic diagram of the spraying location of the alcohol-free soluble release agent in an embodiment of this application. In the diagram, 410 represents the three-pressure stone roller, 420 represents the spraying device for the alcohol-free soluble release agent, 430 represents the drying cylinder, and 440 represents the base paper layer. The pulse spraying frequency of the spraying device 420 is 1:0.8-1.2 with the machine speed. This solves the dual problems of material adhesion to the stone roller and functional agent failure under high-speed operation.

[0034] For closed papermaking systems, a collaborative process of "in-pulp anionic waste control + foam-suppressing rosin sizing + online stone roller cleaning" was designed. The stripping agent is evenly covered on the surface of the stone roller through a pulse nozzle (the spraying frequency is linked to the machine speed (pulse spraying frequency and machine speed ratio 1:0.8-1.2)). The stone roller is then rinsed online with high-pressure clean water (>10 psi) to reduce the sticking caused by the accumulation of impurities in the closed system.

[0035] The control method in this embodiment addresses the shortcomings of existing technologies by providing a comprehensive control process for preventing stone roll adhesion in high-speed paper machine acidic papermaking systems. This process, through the synergistic effect of source control, process optimization, and end-of-pipe treatment, effectively solves the stone roll adhesion problem while eliminating the use of alcohol-containing chemicals, and ensures the stable operation of the closed system and the paper's resistance to lactic acid seepage.

[0036] A specific embodiment will be described below.

[0037] This process is implemented on a closed-loop paper machine with a speed of 1400-1450m / min and a basis weight of 210-350g / m² for producing acidic uncoated white cardboard.

[0038] 1. Source control: Cationic starch and amphoteric dry strength agent (cationic) not only enhance the strength of paper, but also act as anionic waste capture agents in the system. In the later stage, dry powder retention aid (cationic polyacrylamide) and silica (silica sol) are added to further retain various anionic wastes in the sheet and improve the cleanliness of the system.

[0039] 2. Process optimization: Use a foam-suppressing and reinforcing rosin sizing agent with an addition amount of 12-25 kg / ton of paper, and aluminum sulfate with an addition amount of 16-48 kg / ton of paper, and control the on-board pH value to 4.8-5.5.

[0040] 3. Terminal treatment: Prepare an alcohol-free solvent-based stripper (85% isoalkanes, 15% oleic acid polyethylene glycol ester). Apply continuously to the three-pressure stone roller using an air-assisted fan-shaped nozzle spray system at a rate of 65 mL / min.

[0041] Implementation Results: After implementing this process, the stone roller surface was smooth and free of any material adhesion. The paper surface cleanliness was significantly improved, with no holes or spots caused by material adhesion. Subsequent testing showed that the finished paper's resistance to lactic acid seepage fully met customer standards, and the sizing degree was superior to that of traditional processes.

[0042] The method for controlling the anti-sticking material on the stone roll of the high-speed paper machine acidic papermaking system in this application embodiment has the following beneficial effects.

[0043] 1. Comprehensive and effective: Through the triple synergistic effect of "intra-slurry (anionic waste control) - process (antifoaming rosin sizing) - terminal (alcohol-free stripping agent)," the generation and deposition of sticky substances are reduced from the root, completely solving the problem of stone roller sticking under high-speed acid papermaking, improving operating efficiency. Before the addition of chemical agents, the anionic PCD range in the system is -100μeq / L to -300μeq / L; after adding cationic starch and dry strength agent, the slurry PCD is -20μeq / L to -40μeq / L; after further adding talc, aluminum sulfate, rosin, dry powder retention aid, and silica sol, the slurry PCD is -10μeq / L to +10μeq / L.

[0044] 2. Suitable for closed systems: The core alcohol-free silicone stripper formula completely avoids the interference of alcohol chemicals on the front-end rosin sizing, ensuring the stability of the anti-lactic acid edge seepage performance of high-end paper types such as food packaging paper, and is especially suitable for closed water circulation systems.

[0045] 3. Improved Paper Quality: The use of anionic waste traps in antifoaming sizing agents, cationic starch, and amphoteric dry strength agents, along with dry powder retention aids (cationic polyacrylamide) and silica (silica sol), improves the retention of various types of colloids and particles in the system, optimizes the wet-end chemical environment, and the synergistic effect of cationic starch and amphoteric dry strength agents increases the zeta potential of the pulp from -35V to -25V to -5V to +5V. This not only reduces roller sticking but also improves sizing degree and paper uniformity, thus improving overall product quality.

[0046] 4. High cost-effectiveness: Precise chemical addition and spraying control avoid overuse, reduce overall costs, and minimize downtime losses caused by sticking materials.

[0047] The above description is only a part of the embodiments of the present invention and does not limit the scope of protection of the present invention. Any equivalent device or equivalent process transformation made based on the content of the present invention specification and drawings, or direct or indirect application in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for controlling the anti-sticking material on stone rolls in a high-speed paper machine acidic papermaking system, characterized in that, The control method includes: Adding cationic starch and amphoteric dry strength agents to the pulp system reduces anionic waste in the pulp system; Use a foam-suppressing, enhanced rosin sizing agent for in-slurry sizing; The alcohol-free solvent-based stripper is sprayed onto the surface of the stone roller using a spraying device.

2. The control method according to claim 1, characterized in that, The step of adding cationic starch and amphoteric dry strength agent to the pulp system to reduce anionic waste in the pulp system also includes adding dry powder flow aid and silica sol in the later stage to further retain the anionic waste in the system in the paper.

3. The control method according to claim 1, characterized in that, The paper used to make the base paper includes a face layer, a core layer, and a bottom layer. The chemical agents in the face layer include: cationic dispersed rosin at a dosage of 10-20 kg / t pulp, aluminum sulfate solution at a dosage of 10-20 kg / t pulp, and retention aid at a dosage of 0-100 g / t pulp.

4. The control method according to claim 3, characterized in that, The chemical agents in the core layer include: talc powder at a dosage of 100-200 kg / t slurry, cationic starch at a dosage of 15-25 kg / t slurry, dry strength agent at a dosage of 10-20 kg / t slurry, cationic dispersed rosin at a dosage of 10-20 kg / t slurry, aluminum sulfate solution at a dosage of 10-20 kg / t slurry, dry powder retention aid at a dosage of 0-100 g / t slurry, and silica sol at a dosage of 2-5 kg / t.

5. The control method according to claim 4, characterized in that, The underlying chemical components include: cationic dispersed rosin at a dosage of 10-20 kg / t slurry, aluminum sulfate solution at a dosage of 10-20 kg / t slurry, retention aid at a dosage of 250-350 g / t slurry, purple dye at a dosage of 0-20 g / t slurry, and blue dye at a dosage of 50-100 g / t slurry.

6. The control method according to claim 1, characterized in that, In the step of using a foam-suppressing and reinforcing rosin sizing agent for in-slurry sizing, the sizing agent includes maleic anhydride-modified petroleum resin, rosin, and a foam inhibitor.

7. The control method according to claim 6, characterized in that, The dosage of sizing agent is 10-25 kg / ton of paper, and the dosage of aluminum sulfate is 1.5-2.5 times the dosage of sizing agent. The pH value of the pulp on the wire should be controlled between 4.8 and 5.

5.

8. The control method according to claim 1, characterized in that, In the step of spraying the alcohol-free soluble stripping agent onto the surface of the stone roller using a spraying device, the alcohol-free soluble stripping agent comprises: 80%~85% isoparaffin and 15%~20% oleic acid polyethylene glycol ester by mass percentage.

9. The control method according to claim 8, characterized in that, The spraying rate of the alcohol-free solvent-based stripper is 50-80 mL / min / m; the spraying water pressure is 8-15 psi; and the spraying position is the inlet side of the three-pressure stone roller.

10. The control method according to claim 1, characterized in that, The control method is used in the closed system of acidic papermaking for high-speed paper machines with a speed ≥1400 m / min.

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