Papermaking drying part antifouling method and system

Abstract

The invention relates to the technical field of papermaking equipment, and discloses a papermaking drying part antifouling method which comprises the following steps: continuously and uniformly spraying a cleaning agent on the surface of a drying cylinder through a nozzle of a spraying device, so that a layer of protective film for separating the drying cylinder from wet paper sheets is formed on the surface of the drying cylinder; adhesive substances on the drying cylinder and the surface of the paper sheet are isolated through the protective film; the nozzle of the spraying device continuously and uniformly scans and sprays the drying cylinder, so that a layer of protective film is formed on the surface of the drying cylinder, the protective film separates the drying cylinder from a wet paper sheet, stickies, paper lint impurities and the like on the surface of the paper sheet cannot be tightly adhered to the drying cylinder any more, and even if a small part of the stickies and the paper lint impurities are adhered to the drying cylinder, the stickies and the paper lint impurities can be removed by a scraper along with rotation of the drying cylinder. Therefore, the problem that stickers adhere to the surface of the drying cylinder is solved, the service life of the scraper can be prolonged, the surface of the drying cylinder can be prevented from being abraded, and the working effect of the scraper is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of papermaking equipment, and particularly relates to a method and system for preventing pollution in the papermaking drying section. Background Art

[0002] In the papermaking process, the papermaking drying system mainly relies on high-temperature steam to heat the dryer cylinders to remove the moisture of the wet paper web. At the same time, it also determines the paper strength, enhances the smoothness of the paper, and completes the sizing effect of the paper. With the significant increase in the frequency of waste paper recycling, the impurities mixed in the waste paper raw materials continue to increase. These impurities enter the paper machine system as harmful substances, not only causing a significant increase in the processing energy consumption, but also further increasing the production cost.

[0003] Among them, some impurities will adhere to the dryer cylinders, resulting in black patches on the surface of the produced paper sheets, paper machine paper breaks, and product quality problems, seriously affecting the normal operation of the paper machine and the quality of the finished paper. In actual production, most of the problems such as the adhesion of the adhesive substances on the dryer cylinders are removed manually with a scraper after the paper machine stops. Such manual treatment is time-consuming and laborious, not only reducing the service life of the scraper, but also causing wear on the surface of the dryer cylinders, affecting their working effect. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preventing pollution in the papermaking drying section. The dryer cylinders are continuously and evenly scanned and sprayed by a nozzle to form a protective film on their surfaces. The protective film separates the dryer cylinders from the wet paper web, and the adhesive substances and paper fluff impurities on the paper web surface can no longer adhere tightly to the dryer cylinders.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for preventing pollution in the papermaking drying section, including the following steps: continuously and evenly spraying a cleaning agent onto the surface of the dryer cylinders through the nozzles of a spraying device, so as to form a protective film on the surface of the dryer cylinders for separating the dryer cylinders from the wet paper web, and isolating the adhesive substances on the dryer cylinders and the paper web surface through the protective film; for the small amount of adhesive substances and paper fluff impurities attached to the dryer cylinders, they are removed by a scraper as the dryer cylinders rotate.

[0006] Optionally, the spraying device sprays the cleaning agent at the first dryer cylinder where the wet paper web exits the press section.

[0007] Optionally, the nozzles of the spraying device reciprocate along the axial direction of the dryer cylinders, so that the cleaning agent is sprayed onto the surface of the dryer cylinders in a scanning form.

[0008] Optionally, the scanning speed of the nozzles is 0.1 - 0.5 m / s.

[0009] Optionally, the material of the scraper is cemented carbide, and the contact angle between the scraper and the surface of the dryer cylinders is 30° - 60°.

[0010] Optionally, when the spraying device performs scanning spraying, the distance between the nozzle and the surface of the dryer cylinder is maintained between 5 and 15 centimeters.

[0011] Optionally, before using the cleaning agent, the surface of the dryer cylinder is pretreated. The steps of the pretreatment include purging the surface of the dryer cylinder to remove dust and loose impurities.

[0012] Optionally, the cleaning agent is an environment-friendly dryer cylinder cleaning agent mainly composed of bioenzymes, which includes amylase, protease, lipase, deionized water, and a buffer for maintaining the enzyme activity.

[0013] A pollution prevention system for a paper-making drying section includes a storage container for storing the cleaning agent. One end of the storage container is connected with a spraying device, and the spraying device includes a nozzle that can move axially for scanning.

[0014] Optionally, a flow rate regulating device for regulating the spraying flow rate of the cleaning agent is arranged between the storage container and the nozzle of the spraying device.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In the present invention, the nozzle of the spraying device performs continuous and uniform scanning spraying on the dryer cylinder, so that a protective film is formed on its surface. The protective film separates the dryer cylinder from the wet paper sheet, and the adhesives and paper fluff impurities on the surface of the paper sheet can no longer adhere tightly to the dryer cylinder. Even if a small part adheres, it will be removed by the scraper as the dryer cylinder rotates. Thus, problems such as the adhesion of adhesives on the surface of the dryer cylinder are solved, which can not only improve the service life of the scraper, but also avoid the wear of the surface of the dryer cylinder and ensure its working effect; (2) In the present invention, only the first dryer cylinder is sprayed, which can prevent impurities from adhering from the source, lay a good foundation for the subsequent drying process, effectively control the cost and simplify the operation process while ensuring the cleaning effect of the key link; (3) In the present invention, the nozzle reciprocates axially along the dryer cylinder, which can ensure that the cleaning agent is comprehensively and evenly covered, so that a complete and uniform-thickness protective film is formed on the surface of the dryer cylinder, blocking the adhesives and paper fluff impurities on the wet paper sheet from adhering to the dryer cylinder in all directions, improving the stability of the paper sheet quality; it can also adapt to dryer cylinders of different sizes and improve the use efficiency of the cleaning agent. Description of the Drawings

[0016] Figure 1 is a schematic flow chart of the pollution prevention method for the paper-making drying section in the embodiment of the present invention; Figure 2 is a schematic structural diagram of the pollution prevention system for the paper-making drying section in the embodiment of the present invention; Detailed Embodiments

[0017] The present invention will now be further described in detail with reference to the accompanying drawings and embodiments. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present invention in a schematic manner, so they only show the components related to the present invention.

[0018] Embodiment 1, as Figure 1 shown, a method for preventing dirt on the drying section of a paper machine continuously and evenly sprays a cleaning agent onto the surface of the dryer cylinder through the nozzles of a spraying device, so as to form a protective film on the surface of the dryer cylinder for separating the dryer cylinder from the wet paper sheet, and isolating the adhesives on the surfaces of the dryer cylinder and the paper sheet through the protective film; for a small part of the adhesives and paper fluff impurities attached to the dryer cylinder, as the dryer cylinder rotates, they are removed by a scraper.

[0019] Among them, before using the cleaning agent, the surface of the dryer cylinder is pretreated. The steps of the pretreatment include using to blow the surface of the dryer cylinder to remove dust and loose impurities. The pretreatment can be carried out by physical or chemical methods, such as high-pressure water washing, vacuum suction, etc., to remove visible impurities such as dust, paper fluff, and debris on the surface of the dryer cylinder. If these impurities are not removed, they will hinder the full contact between the environmentally friendly dryer cylinder cleaning agent and the surface of the dryer cylinder, affect the adhesion and function of the cleaning agent, and cause the formation of an incomplete or uneven protective film.

[0020] Using a chemical pretreatment agent to treat the surface of the dryer cylinder can change the chemical properties of the surface of the dryer cylinder and increase the active sites on the surface. In this way, the subsequently sprayed cleaning agent can better adhere to the surface of the dryer cylinder, improve the adhesion and stability of the protective film, make it less likely to fall off during the operation of the dryer cylinder, and thus play a role in preventing impurity adhesion more durably.

[0021] The material of the scraper is cemented carbide, and the contact angle between the scraper and the surface of the dryer cylinder is 30° - 60°. Cemented carbide has high hardness, high strength, and good wear resistance, and can maintain its shape and performance stable during the process of long-term contact with the surface of the dryer cylinder and scraping impurities, and is not easily worn and deformed. The dryer cylinder rotates continuously at a high speed, and the scraper needs to bear a large amount of frictional force and impact force. Using cemented carbide material can meet the requirements of this high-intensity work.

[0022] Through a large number of practices and theoretical studies, when the contact angle between the scraper and the surface of the dryer cylinder is within the range of 30° - 60°, it can ensure the effective scraping of impurities by the scraper while minimizing the wear of the scraper on the surface of the dryer cylinder to the greatest extent. If the angle is too small, the scraping force of the scraper on the impurities is insufficient; if the angle is too large, the frictional force between the scraper and the dryer cylinder will increase, accelerating the wear of the scraper and the dryer cylinder.

[0023] Specifically, the nozzle of the spraying device continuously and evenly scans and sprays the drying cylinder to form a protective film on its surface. The protective film separates the drying cylinder from the wet paper sheet, preventing the adhesives and paper fluff impurities on the paper sheet surface from adhering tightly to the drying cylinder. Even if a small amount adheres, it will be removed by the scraper as the drying cylinder rotates, thus solving problems such as the adhesion of adhesives on the drying cylinder surface. This can not only improve the service life of the scraper but also avoid the wear of the drying cylinder surface and ensure its working effect.

[0024] As described above, the spraying device sprays the cleaning agent onto the first drying cylinder where the wet paper sheet exits the press section.

[0025] The wet paper sheet exiting the press section has a high water content and carries a large amount of adhesives, paper fluff impurities, etc. At this time, the first drying cylinder is the first key equipment that the wet paper sheet contacts for drying. If a large amount of impurities adhere and accumulate on the surface of the first drying cylinder, it will not only affect the normal operation of this drying cylinder but also lead to a poor fitting state between the subsequent wet paper sheet and the drying cylinder, thereby affecting the drying efficiency and the quality of the paper sheet. Focusing on protecting the first drying cylinder can prevent impurities from adhering at the source and lay a good foundation for the subsequent drying process.

[0026] If each drying cylinder is sprayed for cleaning, it will significantly increase the usage amount of the environmentally friendly drying cylinder cleaning agent and raise the production cost. At the same time, spraying multiple drying cylinders requires arranging more spraying devices, increasing the equipment procurement, installation, and maintenance costs. The operation process will also become more complex, and the failure risk will increase accordingly. Spraying only the first drying cylinder can effectively control the cost and simplify the operation process while ensuring the cleaning effect of the key link.

[0027] After the first drying cylinder is sprayed to form a protective film, it can effectively block most impurities. During the operation of the subsequent drying cylinders, since the wet paper sheet undergoes preliminary drying and impurity separation on the first drying cylinder, the impurities it carries are significantly reduced. Moreover, the rotation movement of the subsequent drying cylinders themselves and their relative movement with the paper sheet can also play a certain self-cleaning role. In addition, there are usually general cleaning equipment (such as scrapers) for all drying cylinders in the entire drying system. These measures can further ensure the cleanliness of the subsequent drying cylinders. Therefore, it is not necessary to spray a special cleaning agent on each drying cylinder, and only spraying the first drying cylinder is sufficient.

[0028] Furthermore, the cleaning agent uses an environmentally friendly drying cylinder cleaning agent mainly composed of biological enzymes, which includes amylase, protease, lipase, deionized water, and a buffer for maintaining the enzyme activity. And the mass ratio of amylase, protease, lipase, and buffer is 20% - 50%, 10% - 30%, 5% - 20%, and 5% - 20% in sequence, with the balance being deionized water.

[0029] An environmentally friendly dryer cleaning agent mainly composed of biological enzymes uses the specific catalytic action of enzymes to decompose various impurities. While ensuring the cleanliness of the dryer, it is environmentally friendly and conforms to the concept of sustainable development.

[0030] Amylase can efficiently decompose starch-based adhesives remaining in the paper production process. When making paper, starch is often added to enhance the strength of the paper, and this starch is likely to remain and adhere to the surface of the dryer during the drying stage. Amylase can hydrolyze large starch molecules into small molecule substances such as maltose and glucose, making them lose their adhesiveness and facilitating their removal from the dryer surface.

[0031] When the proportion of amylase in the cleaning agent is 20%, it is more suitable for production scenarios with relatively low starch-based impurity content. For example, in the production of some special papers using new fiber raw materials and with less starch sizing, a relatively low content of amylase can effectively decompose the small amount of residual starch adhesives. Although the decomposition efficiency is relatively limited, it can reduce costs while ensuring the cleaning effect, and will not interfere with other components due to excessive amylase.

[0032] When the proportion of amylase in the cleaning agent is 35%, it is suitable for most conventional paper production. In the production processes of newsprint, writing paper, etc., starch-based adhesives are common impurities. A 35% amylase content can provide a relatively sufficient amount of enzyme to efficiently decompose starch, hydrolyze it into small molecule sugars, significantly reduce the adhesion force of starch adhesives to the dryer, ensure the cleanliness of the dryer surface, and maintain the continuity and quality stability of paper production.

[0033] When the proportion of amylase in the cleaning agent is 50%, in the case of a large amount of starch-based impurities, such as in the production of some papers using traditional processes with a large amount of starch sizing, a 50% amylase content can exert its maximum efficiency. It can quickly and thoroughly decompose a large amount of starch, effectively deal with the cleaning problem of high-concentration starch adhesives, and ensure that the dryer can still operate normally under a high impurity load.

[0034] Protease is specifically used to decompose protein-based impurities. Proteins in paper raw materials, protein-based additives added during the papermaking process, etc. may all form stubborn protein dirt on the surface of the dryer. Protease can cut the peptide bonds of proteins, degrading them into amino acids or small peptide fragments, thus achieving the cleaning purpose. In the production of special papers, such as processes using protein-based additives like animal glue, protease-based cleaning agents play an important role in effectively preventing the accumulation of protein-based impurities on the dryer surface and ensuring the normal operation of the dryer.

[0035] When the proportion of protease in the cleaning agent is 10%, if the protein content in the papermaking raw materials is low, or the usage amount of protein-based additives in the production process is low, a protease content of 10% is sufficient to decompose a small amount of protein impurities. In the production of some papers with pure wood pulp as the raw material and simple additives, this proportion can meet the basic protein cleaning requirements, prevent protein from accumulating on the dryer surface to form dirt, and at the same time maintain a relatively low overall cost of the cleaning agent.

[0036] When the proportion of protease in the cleaning agent is 20%, for most papermaking processes, the raw materials and additives will contain a certain amount of protein. A protease content of 20% can better handle this common situation, effectively cut the protein peptide bond, degrade the protein into amino acids or small peptide fragments, making it easy to remove from the dryer surface, ensuring the cleanliness of the dryer, improving the paper quality, and achieving a balance between cost and cleaning effect.

[0037] When the proportion of protease in the cleaning agent is 30%, in the production of specialty papers, such as processes that use more protein-based additives like animal glue, a protease content of 30% can fully play its role. It can quickly decompose a large amount of protein impurities, solve the problem of dryer surface contamination caused by protein adhesion, and ensure that the paper production is not affected by protein dirt.

[0038] Taking lipase as the main active ingredient, it can decompose oil and fat substances. During the papermaking process, equipment lubricating oil leakage, oil and fat contained in the paper raw materials, etc. may all contaminate the dryer surface. Lipase can hydrolyze the oil and fat into fatty acids and glycerol, reduce the viscosity of the oil and fat, and make it easy to be washed away. When producing coated paper, if the oil and fat components in the coating liquid remain on the dryer, lipase-based cleaning agents can effectively remove them, ensure the smoothness of the dryer surface, and avoid the adverse effects of oil and fat on the coating effect of the paper sheet.

[0039] When there are fewer oil and fat pollutants on the dryer surface, such as when the risk of equipment lubricating oil leakage is low and the fat and oil content in the paper raw materials is low, a lipase content of 5% can meet the basic cleaning requirements. It can slowly decompose a small amount of oil and fat, hydrolyze it into fatty acids and glycerol, prevent the oil and fat from forming an oil film on the dryer surface, affect the paper quality, and at the same time maintain the cleaning agent cost at a relatively low level.

[0040] For general papermaking production, there may be a small amount of lubricating oil leakage during the operation of the equipment, and the paper raw materials may also contain a certain amount of oil and fat. A lipase content of 12.5% can effectively handle this situation. It can timely decompose oil and fat impurities, keep the dryer surface dry and clean, avoid the adverse effects of oil and fat on the paper sheet, and achieve a good balance between cost and cleaning efficiency.

[0041] When producing papers with extremely high requirements for the cleanliness of the dryer cylinder surface, such as coated paper, the coating solution may contain a relatively high amount of oil components. At this time, a 20% lipase content can strongly decompose the oil, quickly remove a large amount of oil-based pollutants, ensure no oil residue on the dryer cylinder surface, and guarantee the coating effect of the paper.

[0042] In the environmentally friendly dryer cylinder cleaning agent mainly composed of bioenzymes, the buffer plays a crucial role, such as stabilizing enzyme activity, preventing enzyme denaturation, and enhancing the stability of the cleaning agent. And it includes but is not limited to phosphate buffer, borate buffer, and citrate buffer.

[0043] The activity of bioenzymes is extremely sensitive to the environmental pH value. Different enzymes can exhibit the best activity within a specific pH value range. For example, amylase usually has a higher activity at a pH value of 6.0 - 7.0, while protease has the best catalytic effect at a pH value of 7.5 - 8.5. The buffer can regulate and stabilize the pH value of the cleaning agent, keeping it within the optimal pH range of the bioenzyme. The presence of the buffer can effectively resist pH value changes, ensure that the bioenzyme is always in an active state, and continuously and efficiently decompose the adhesives and paper fluff impurities on the paper surface.

[0044] An inappropriate pH value will not only reduce enzyme activity but may also cause a change in the spatial conformation of enzyme molecules, thereby causing the enzyme to denature and inactivate. The buffer avoids the enzyme denaturation phenomenon caused by the deviation of the pH value from the optimal range by stabilizing the pH value. Taking lipase as an example, in an overly acidic or alkaline environment, its molecular structure may be damaged and lose the ability to decompose oil. The buffer can create a relatively stable chemical environment, protect the structural integrity of enzyme molecules, extend the service life of bioenzymes in the cleaning agent, ensure that the bioenzymes can maintain good performance during storage and use, and effectively play the role of cleaning the impurities on the dryer cylinder surface.

[0045] The buffer helps to maintain the chemical stability of the entire cleaning agent system. During the storage of the cleaning agent, slow chemical reactions may occur due to factors such as contact with air and temperature changes, resulting in a change in the pH value. The buffer can inhibit this pH value drift and prevent adverse reactions between other components caused by pH value changes. For example, in a cleaning agent containing multiple enzymes and other additives, an inappropriate pH value may cause some components to precipitate or flocculate, affecting the uniformity and use effect of the cleaning agent. The buffer avoids the occurrence of these adverse phenomena by stabilizing the pH value, ensuring that the cleaning agent always maintains stable performance during storage and use, and providing a reliable guarantee for dryer cylinder cleaning.

[0046] In the case where the production environment is relatively stable and the pH value fluctuates little, a buffer content of 5% can maintain the activity of bioenzymes. It can stabilize the pH value of the cleaning agent to a certain extent, provide a suitable microenvironment for bioenzymes, ensure the normal catalytic function of the enzymes, and will not affect the performance of other components due to excessive buffer, and the cost is relatively low.

[0047] There are certain pH value fluctuations in the environment of most paper-making production workshops. A buffer content of 12.5% can effectively cope with this situation. It can better stabilize the pH value of the cleaning agent system, ensure that amylase, protease, lipase, etc. exert their maximum activity under suitable acidity and alkalinity, guarantee the decomposition effect on various impurities, and balance the cost and buffering effect at the same time.

[0048] When the production environment is complex and the pH value changes greatly, such as in some paper-making processes using special chemical additives or recycled fibers, a buffer content of 20% can provide a strong buffering capacity. It can maintain the stability of the pH value of the cleaning agent to the greatest extent, enable bioenzymes to remain active under extreme pH value fluctuations, and effectively decompose impurities.

[0049] Deionized water, as the main solvent of the cleaning agent, is used to dissolve and dilute other components such as surfactants and dispersants, so that they can be evenly mixed and play their roles. At the same time, it provides a necessary medium environment for the formation of the protective film, and its proportion is determined according to the performance of other components and the required concentration.

[0050] In addition, the nozzle of the spraying device reciprocates along the axial direction of the dryer cylinder, so that the cleaning agent is sprayed on the surface of the dryer cylinder in a scanning form.

[0051] The dryer cylinder is usually cylindrical and has a certain length in the axial direction. The nozzle moves and scans along the axial direction, which can ensure that the entire surface from one end to the other end of the dryer cylinder can receive the environmentally friendly dryer cylinder cleaning agent evenly. This effectively avoids the situation that the two ends or the middle part of the dryer cylinder cannot be sprayed properly due to the fixed position of the nozzle, and forms a complete and uniform-thickness protective film on the surface of the dryer cylinder, blocking the adhesion of adhesives and paper fluff impurities on the wet paper sheet to the dryer cylinder in all directions, and improving the stability of the paper sheet quality.

[0052] In the paper-making industry, the sizes and specifications of dryer cylinders are diverse. The design of the nozzle moving and scanning along the axial direction can be flexibly adapted to dryer cylinders of various lengths; whether it is a small dryer cylinder or a large industrial dryer cylinder, only by adjusting the moving stroke of the nozzle can the cleaning requirements of dryer cylinders of different sizes be met, enhancing the versatility and applicability of the entire dryer cylinder cleaning solution, and reducing the cost for enterprises to frequently adjust the cleaning equipment due to replacing dryer cylinders of different specifications.

[0053] Compared with spraying at a fixed position, axial movement scanning enables the cleaning agent to act precisely on the surface of the dryer, reducing the waste of the cleaning agent caused by over-concentrated spraying in a certain area. Through uniform and appropriate spraying, while ensuring the cleaning effect, the usage efficiency of the cleaning agent is maximized, and the production cost is reduced.

[0054] Among them, the scanning speed of the nozzle is 0.1 - 0.5 m / s, and when the spraying device is scanning and spraying, the distance between the nozzle and the surface of the dryer is maintained between 5 - 15 cm.

[0055] The dryer has a variety of size specifications, and the circumference of a common large dryer can reach several meters. The scanning speed of the nozzle within the range of 0.1 - 0.5 m / s can not only ensure the complete spraying of the dryer surface within a reasonable time, but also prevent uneven spraying of the cleaning agent due to too fast a speed, and at the same time avoid affecting the production efficiency due to too slow a speed.

[0056] When the scanning speed of the nozzle is 0.1 m / s, at this relatively low speed, the environmentally friendly dryer cleaning agent has sufficient time to spread on the surface of the dryer; when the scanning speed of the nozzle is 0.3 m / s, this speed takes into account both spraying uniformity and production efficiency, and the cleaning agent can form a protective film on the surface of the dryer better, making the cleaning frequency of the doctor blade moderate, ensuring both the paper quality and maintaining a high production speed, meeting the needs of most conventional papermaking production, and achieving a good balance between quality and efficiency; when the scanning speed of the nozzle is 0.5 m / s, at high-speed spraying, the production efficiency is greatly improved, and more paper can be dried per unit time, significantly enhancing the production capacity.

[0057] The distance between the nozzle and the surface of the dryer is maintained between 5 - 15 cm. This distance range can ensure that after the environmentally friendly dryer cleaning agent is ejected from the nozzle, when it reaches the surface of the dryer, it can still maintain a relatively concentrated spraying state, and will not cause excessive local spraying due to too close a distance.

[0058] When the distance is 5 cm, the cleaning agent can contact the surface of the dryer with a relatively high concentration and a small diffusion range, which is suitable for key cleaning of some areas with more local impurities; while a distance of 15 cm can make the cleaning agent diffuse to a certain extent on the surface of the dryer, ensuring uniform coverage of a large area, forming a complete and uniform-thickness protective film, and effectively preventing the adhesion of paper impurities to the dryer.

[0059] In actual production, the spraying flow rate and scanning speed of the nozzle will be adjusted according to the specific conditions of the dryer cylinder. A distance range of 5 - 15 cm can better adapt to different combinations of flow rate and speed. When the spraying flow rate is large, appropriately increasing the distance (such as 10 - 15 cm) can allow the cleaning agent to have enough space to be evenly dispersed on the surface of the dryer cylinder. When the scanning speed is fast, a relatively short distance (such as 5 - 10 cm) can ensure that the dryer cylinder surface can still receive a sufficient amount of cleaning agent in a short time, thus ensuring good cleaning effects under various working conditions.

[0060] Example 2, based on Example 1, the present invention also proposes a pollution prevention system for the paper drying section.

[0061] As Figure 2 shown, a pollution prevention system for the paper drying section includes a storage container for storing the cleaning agent, and a spraying device is connected to one end of the storage container. For the wet paper sheet coming out of the press section, an environment-friendly dryer cylinder cleaning agent is used at the first dryer cylinder. Through the movable scanning spraying device, its nozzle is used to continuously and evenly scan and spray the dryer cylinder, so that a protective film is formed on the surface of the dryer cylinder. The protective film is used to separate the dryer cylinder and the wet paper sheet. The adhesives and paper fluff impurities on the surface of the paper sheet can no longer adhere tightly to the dryer cylinder. Even if a small part adheres, it will be removed by the scraper as the dryer cylinder rotates, thus solving problems such as the adhesion of adhesives on the surface of the dryer cylinder. As described above, the spraying device includes a guide rail and a nozzle arranged on the guide rail. The nozzle can move along the guide rail to achieve scanning and spraying of the dryer cylinder. The guide rail is parallel to the axis direction of the dryer cylinder, and the nozzle can be driven by an existing linear module to achieve automatic reciprocating scanning and spraying.

[0062] Furthermore, a flow rate regulating device for regulating the spraying flow rate of the cleaning agent is arranged between the storage container and the nozzle of the spraying device, and a pump body is also arranged between the flow rate regulating device and the storage container.

[0063] The pump body can provide sufficient pressure for the environment-friendly dryer cylinder cleaning agent, so that it can be smoothly pumped out from the storage container and sprayed onto the surface of the dryer cylinder at a certain speed through the nozzle. For example, a centrifugal pump is used. It uses the centrifugal force generated by the high-speed rotation of the impeller to transport the cleaning agent from the storage container with a lower pressure to the nozzle with a higher pressure requirement, ensuring that the cleaning agent can overcome the pipeline resistance and air resistance and be accurately sprayed on the surface of the dryer cylinder to form a protective film.

[0064] The function of the flow rate regulating device is to precisely control the flow rate of the cleaning agent flowing from the storage container to the nozzle, and the flow rate adjustment is achieved by changing the cross-sectional area of the flow channel, the opening of the valve, etc. For example, a common throttle valve changes the size of the valve port by rotating the valve stem. When the valve port is adjusted to be smaller, the flow channel becomes narrower and the flow rate of the cleaning agent will decrease accordingly; conversely, when the valve port is adjusted to be larger, the flow rate increases.

[0065] In summary, the present invention utilizes a movable scanning and spraying device, enabling its nozzle to perform continuous and uniform scanning spraying on the dryer cylinder horizontally. The spraying device is small and easy to install, and an environment-friendly dryer cylinder cleaning agent mainly composed of biological enzymes is used, enabling it to effectively adhere to the surface of the dryer cylinder, form a protective film between the dryer cylinder and the wet paper sheet, reduce wear while the doctor blade is working, and improve the service life of the doctor blade.

[0066] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0067] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "install", "connect", "couple" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0068] Based on the inspiration of the ideal embodiments of the present invention, through the above description, relevant personnel can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A method for preventing fouling in a papermaking drying section, characterized in that: The following steps are involved: The cleaning agent is sprayed continuously and evenly onto the surface of the dryer through the nozzle of the spraying device, so that a protective film is formed on the surface of the dryer to separate the dryer and the wet paper sheet. The protective film isolates the dryer from the adhesives on the surface of the paper sheet. A small amount of adhesives and paper fiber impurities attached to the dryer are removed by a scraper as the dryer rotates.

2. The antifouling method for the papermaking drying section according to claim 1, characterized in that: The spraying device sprays the cleaning agent onto the first drying cylinder of the wet paper sheet exiting the press section.

3. The antifouling method for the papermaking drying section according to claim 1, characterized in that: The nozzle of the spraying device reciprocates along the axial direction of the drying cylinder, so that the cleaning agent is sprayed on the surface of the drying cylinder in a scanning form.

4. The antifouling method for the papermaking drying section according to claim 3, characterized in that: The scanning speed of the nozzle is 0.1-0.5 m / s.

5. The antifouling method for the papermaking drying section according to claim 1, characterized in that: The scraper is made of hard alloy, and the contact angle between the scraper and the surface of the drying cylinder is 30°-60°.

6. The antifouling method for the papermaking drying section according to claim 1, characterized in that: When the spraying device is performing scanning spraying, the distance between the nozzle and the surface of the drying cylinder is maintained between 5 and 15 centimeters.

7. The antifouling method for the papermaking drying section according to claim 1, characterized in that: Before using the cleaning agent, the surface of the drying cylinder is pretreated, and the pretreatment step includes blowing the surface of the drying cylinder to remove dust and loose impurities.

8. The antifouling method for the papermaking drying section according to claim 1, characterized in that: The cleaning agent is an environmentally friendly drying cylinder cleaning agent mainly based on biological enzymes, which contains amylase, protease, lipase, deionized water and a buffer for maintaining enzyme activity.

9. A system for the anti-fouling method for the papermaking drying section according to any one of claims 1 to 8, characterized in that: The invention comprises a storage container for storing a cleaning agent. One end of the storage container is connected with a spraying device. The spraying device comprises a nozzle which can be moved and scanned along the axial direction.

10. The anti-fouling system for the papermaking drying section according to claim 9, characterized in that: A flow regulating device for regulating the spraying flow of the cleaning agent is arranged between the storage container and the nozzle of the spraying device.

Images