A reaction device and method for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemi-mechanical pulp

Abstract

The application discloses a reaction device for improving bleaching efficiency of a non-silicon hydrogen peroxide stabilizer in a chemi-mechanical pulp and a method thereof. The reaction device comprises a shell, a first reaction cavity and a second reaction cavity are arranged in the shell, the first reaction cavity comprises a first sub-reaction cavity and a second sub-reaction cavity, the second sub-reaction cavity comprises one or more, a first detection area is defined between the first sub-reaction cavity and the second sub-reaction cavity, a second detection area is defined between two adjacent second sub-reaction cavities, a second dosing port and a detection port corresponding to the second sub-reaction cavity are arranged on the shell, the detection port is arranged downstream of the corresponding second dosing port along the moving direction of the bleaching material, and a dosing device is used for adding sodium hydroxide solution into the corresponding second sub-reaction cavity through the second dosing port. According to the reaction device, the deficiency of the non-silicon stabilizer in the pH adjusting capacity is effectively compensated, and the reaction efficiency and the bleaching uniformity of the non-silicon bleaching process are improved.

Description

Technical Field

[0001] This invention relates to the field of chemimechanical pulping and bleaching technology, and in particular to a reaction apparatus and method for improving the bleaching efficiency of chemimechanical pulp using non-silicon hydrogen peroxide stabilizers. Background Technology

[0002] Alkaline hydrogen peroxide bleaching is currently the most commonly used bleaching method for chemimechanical pulp. In the pre-treatment of pulping, alkali is used to swell and soften the cell walls of fibers. The purpose is to allow the refining process to primarily expose the lignin on the surface of the microfibrils through friction, rather than cutting the fibers, thereby maximizing the exposure of the microfibrils and providing a foundation for paper strength. However, the reaction between alkali and lignin inevitably produces conjugated chromophores. The basic principle of chemimechanical pulp bleaching is to achieve selective oxidative decolorization of lignin through the synergistic effect of alkali and hydrogen peroxide. In this process, the primary role of alkali is to promote the dissociation of hydrogen peroxide, generating hydrogen peroxide ions (HO2) with strong nucleophilic activity. - This ion can attack and destroy chromophores and auxochromes such as quinones and carbonyl groups in the lignin structure, converting them into colorless small molecules. Furthermore, the alkaline environment maintained by the alkali can continuously supply HO2. - It can also cause the fibers to swell, promote the ionization and dissolution of lignin, thereby improving the permeability of the bleaching solution. Therefore, the reaction between the alkali and lignin is constantly occurring, and chromophores are continuously generated. Thus, the entire bleaching process requires maintaining a certain concentration of hydrogen peroxide and adding a hydrogen peroxide stabilizer.

[0003] In traditional processes, hydrogen peroxide stabilizers typically employ sodium silicate in combination with chelating agents. The chelating agent controls the release of free metal ions (mainly iron, manganese, and copper) from the cell cavities of the fiber raw materials during bleaching, preventing them from catalyzing the decomposition of hydrogen peroxide. Sodium silicate is considered to possess multiple functions, including chelating metal ions, adjusting the pH of the system, and forming colloids to seal overly oxidizing hydroxyl radicals. However, with the continuous expansion of chemimechanical pulp production scale and increasingly fierce competition among enterprises, manufacturing cost control has become extremely stringent. Sodium silicate added during bleaching readily combines with calcium, magnesium, and iron ions in the system to form precipitates that adhere to equipment surfaces, affecting the operating efficiency of filtration equipment such as multi-disc filters and pressure screens, forcing production line shutdowns. The cost of shutting down a large production line once can approach one million yuan. Therefore, in recent years, large-scale chemimechanical pulp bleaching production lines have gradually abandoned sodium silicate and switched to non-silicone hydrogen peroxide stabilizers composed of chelating agents and surfactants. However, practical use shows that the bleaching effect of non-silicone stabilizers is consistently poor because the silicone-free bleaching process lacks the pH adjustment capability of sodium silicate. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a reaction apparatus for improving the bleaching efficiency of non-silicone hydrogen peroxide stabilizers in chemimechanical pulps. This apparatus can effectively compensate for the shortcomings of non-silicone stabilizers in pH adjustment, significantly improving the reaction efficiency and bleaching uniformity of the non-silicone bleaching process; simultaneously, it can accurately determine the bleaching endpoint, thereby effectively avoiding under-bleaching or over-bleaching problems.

[0005] This invention also proposes a method for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulp.

[0006] A reaction apparatus for improving the bleaching efficiency of non-silicone hydrogen peroxide stabilizers in chemical mechanical pulp according to a first aspect of the present invention is used for bleaching materials to be bleached, comprising: a shell having an inlet end and an outlet end, wherein the materials to be bleached are adapted to move from the inlet end of the shell toward the outlet end of the shell and to react chemically with a chemical agent within the shell; the shell is provided with a first reaction chamber and a second reaction chamber sequentially connected along the direction of movement of the bleached materials; the first reaction chamber includes: a first sub-reaction chamber and a second sub-reaction chamber sequentially arranged along the direction of movement of the bleached materials; the second sub-reaction chamber includes one or more, and the multiple second sub-reaction chambers are sequentially arranged along the direction of movement of the bleached materials; a first detection zone is defined between the first sub-reaction chamber and the second reaction chamber; a second detection zone is defined between two adjacent second sub-reaction chambers; the shell is also provided with a first dosing port connected to the first sub-reaction chamber. A second dosing port and a detection port, each corresponding to and connected to the second sub-reaction chamber, and a discharge port connected to the second reaction chamber, are arranged downstream of the corresponding second dosing port along the direction of movement of the bleaching material. A dosing device adds sodium hydroxide solution, non-silicone stabilizer, chelating agent, and hydrogen peroxide solution to the first sub-reaction chamber through the first dosing port, and adds sodium hydroxide solution to the corresponding second sub-reaction chamber through each of the second dosing ports. A first detector is used to detect the pH value of the bleaching material in the first detection area. A second detector, located at the detection port, is used to detect the pH value of the bleaching material mixed with the sodium hydroxide solution in the second sub-reaction chamber. A third detector is used to detect the pH value of the bleaching material in the second detection area. A driving device is used to drive the bleaching material to move from the inlet end of the shell towards the outlet end of the shell.

[0007] According to the reaction apparatus of the present invention, by setting up multiple detectors and at least one second sub-reaction chamber, the pH value during the bleaching process can be monitored and dynamically adjusted in real time, so that the pH value of the material is always maintained in the suitable range of 11.2 to 11.8 throughout the bleaching process. This effectively makes up for the lack of pH adjustment capability of non-silicone stabilizers and significantly improves the reaction efficiency and bleaching uniformity of the non-silicone bleaching process. At the same time, through multi-point discharge and real-time whiteness detection, the bleaching endpoint can be accurately determined, effectively avoiding under-bleaching or over-bleaching problems.

[0008] According to some embodiments of the present invention, the second reaction chamber includes a third sub-reaction chamber and a fourth sub-reaction chamber that are sequentially connected in the direction of movement of the bleaching material. The third sub-reaction chamber is used for the bleaching material to react with the chemical agent for a target duration. The discharge port is located at the outlet end of the fourth sub-reaction chamber. In the direction of movement of the bleaching material, the length of the fourth sub-reaction chamber is less than the length of the third sub-reaction chamber.

[0009] According to some embodiments of the present invention, there are multiple fourth sub-reaction chambers, which are arranged sequentially along the moving direction of the bleaching material. Each fourth sub-reaction chamber is provided with a discharge port. The reaction device further includes: a fourth detector for detecting the pH value of the material to be bleached at the discharge port; a sampling device for collecting the material to be bleached at the discharge port to prepare a test sample; and a whiteness detector for detecting the whiteness of the test sample.

[0010] According to some embodiments of the present invention, the dosing device further includes: a first dosing tank for storing a non-silicone stabilizer, the first dosing tank being connected to a first dosing port via a first dosing pipe, and a first dosing pump for pumping the non-silicone stabilizer connected in series on the first dosing pipe; a second dosing tank for storing a chelating agent, the second dosing tank being connected to the first dosing port via a second dosing pipe, and a second dosing pump for pumping the chelating agent connected in series on the second dosing pipe; a third dosing tank for storing the sodium hydroxide solution, the third dosing tank being connected to the first dosing port and a second dosing port via a third dosing pipe, and a third dosing pump for pumping the sodium hydroxide solution connected in series on the third dosing pipe; and a fourth dosing tank for storing the hydrogen peroxide solution, the fourth dosing tank being connected to the first dosing port via a fourth dosing pipe, and a fourth dosing pump for pumping the hydrogen peroxide solution connected in series on the fourth dosing pipe.

[0011] According to some embodiments of the present invention, the housing includes: a first housing extending along a first direction, wherein the first reaction chamber is disposed within the first housing; and a second housing extending along the first direction and spaced apart from the first housing in a second direction, wherein the second reaction chamber is disposed within the second housing, and the first housing and the second housing are connected.

[0012] According to some embodiments of the present invention, the driving device includes: a first driving device for driving the material to be bleached within the first housing to move along the first direction; and a second driving device for driving the material to be bleached within the second housing to move along the first direction.

[0013] According to some embodiments of the present invention, the first driving device includes: a first rotating shaft and a first bushing, the first rotating shaft extending along the first direction and disposed within the first housing, the axis of the first rotating shaft coinciding with the axis of the first housing, the first bushing being sleeved on the outer side of the first rotating shaft, and the outer side of the first bushing being provided with a first blade extending helically along the axial direction of the first rotating shaft; a first driving member connected to one end of the first rotating shaft for driving the first rotating shaft to rotate, thereby driving the material to be bleached to move along the first direction; and / or, the second driving device includes:

[0014] A second rotating shaft and a second bushing, the second rotating shaft extending along the first direction and arranged inside the second housing, the axis of the second rotating shaft coinciding with the axis of the second housing, the second bushing being sleeved on the outer side of the second rotating shaft, and the outer side of the second bushing being provided with a second blade extending spirally along the axial direction of the second rotating shaft; a second driving member, the second driving member being connected to one end of the second rotating shaft, for driving the second rotating shaft to rotate, so as to drive the material to be bleached to move along the first direction.

[0015] According to some embodiments of the present invention, at least one steam inlet is formed on the sidewalls of the first reaction chamber and the second reaction chamber, and the reaction device further includes: an air inlet pipe, one end of which is connected to the steam inlet and the other end of which is adapted to be connected to an external steam source; and / or, a flow turbulence member, which is disposed on at least a portion of the inner wall of the housing, and on at least a portion of the first blade and at least a portion of the second blade; and / or, a sealing member, which is disposed on the housing and is used to open or cover the discharge port.

[0016] The method for improving the bleaching efficiency of non-silica hydrogen peroxide stabilizers in chemical mechanical pulp according to a second aspect of the present invention, used in the reaction apparatus for improving the bleaching efficiency of non-silica hydrogen peroxide stabilizers in chemical mechanical pulp according to a first aspect of the present invention, the method comprising: the method comprising:

[0017] Step S1: Add the material to be bleached into the first reaction chamber through the feed inlet;

[0018] Step S2: A first portion of sodium hydroxide (60%–75% of the total sodium hydroxide content), non-silicone stabilizer, chelating agent, and hydrogen peroxide solution are added to the first reaction chamber through the first dosing port to mix with the material to be bleached. Simultaneously, steam is introduced into the first reaction chamber to raise the temperature to a preset level. Step S3: The reaction time of the material to be bleached in the first sub-reaction chamber is controlled to reach a first preset duration. Step S4: The pH value of the first detection zone is checked to ensure it meets a first preset value. If the pH value is lower than the first preset value, a first strategy is executed; if the pH value is not lower than the first preset value, a second strategy is executed. The process includes: adding sodium hydroxide solution to the second sub-reaction chamber through the second dosing port to bring the pH value to a second preset value, which is greater than the first preset value; controlling the reaction time of the material to be bleached in the second sub-reaction chamber to reach a second preset duration; confirming whether the pH value of the second detection zone meets the first preset value; if the pH value is lower than the first preset value, repeating the first strategy until the total amount of sodium hydroxide has been added; if the pH value is not lower than the first preset value, executing the second strategy; the second strategy includes: controlling the reaction time of the material to be bleached in the second sub-reaction chamber to reach the second preset duration. Set a time limit and confirm whether the pH value of the second detection zone meets the first preset value. If the pH value is lower than the first preset value, repeat the first strategy until the total amount of sodium hydroxide is added. If the pH value is not lower than the first preset value, execute the second strategy. Step S5: Control the reaction time of the material to be bleached in the third sub-reaction chamber to reach the target time to obtain bleached material. Step S6: Detect the whiteness of the bleached material and confirm whether the whiteness reaches the preset whiteness value. If the whiteness reaches the preset whiteness value, execute the third strategy. If the whiteness is lower than the preset whiteness value, execute the fourth strategy. The third strategy includes: discharging the bleached material through the discharge channel. The fourth strategy includes: confirming whether the pH of the bleaching material is higher than a third preset value; if so, after the bleaching material enters the fourth sub-reaction chamber and continues to react for a second preset time, confirming whether the whiteness at the outlet position reaches a preset whiteness value; if the whiteness reaches the preset whiteness value, executing the third strategy; if the whiteness does not reach the preset whiteness value, executing the fourth strategy until the whiteness reaches the preset whiteness value; if not, discharging the bleaching material through the outlet and replenishing the first sub-reaction chamber with hydrogen peroxide solution through the first dosing port, and then repeating steps S3-S6 until the whiteness reaches the preset whiteness value.

[0019] According to the method of the present invention, by monitoring the pH value and whiteness of the slurry throughout the process, the deficiency of non-silicone stabilizers in pH adjustment can be effectively compensated, thereby effectively improving the reaction efficiency of the non-silicone bleaching process. At the same time, under the same chemical dosage, the whiteness of the bleached slurry treated by this process can reach a level comparable to that of the traditional sodium silicate process, thus ensuring the bleaching quality. In addition, the method has strong automation and controllability, which can reduce unnecessary consumption of bleaching agents and can be adapted to various slurry conditions. Therefore, it is applicable to the promotion and application of non-silicone bleaching processes in large-scale mechanical pulp production lines.

[0020] According to some embodiments of the present invention, the first preset value is 11.2-11.8, the second preset value is 12, the third preset value is 9, the whiteness value is 75%ISO-81%ISO, the first preset duration is 15min-20min, the target duration is 30min, and the second preset duration is 10min-20min.

[0021] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a reaction apparatus according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of a reaction apparatus according to another embodiment of the present invention;

[0024] Figure 3 It is along Figure 2 The cross-sectional view of line AA shown;

[0025] Figure 4 It is along Figure 2 The cross-sectional view of the BB line shown;

[0026] Figure 5 yes Figure 2 The enlarged view of point A circled in the image.

[0027] Figure label:

[0028] 100. Reaction apparatus;

[0029] 10. Shell; 11. First reaction chamber; 111. First sub-reaction chamber; 112. Second sub-reaction chamber; 12. Second reaction chamber; 121. Third sub-reaction chamber; 122. Fourth sub-reaction chamber; 13. Feed inlet; 14. First dosing port; 141. First sub-dosing port; 142. Second sub-dosing port; 15. Second dosing port; 16. Discharge port; 17. Steam inlet; 10a. First shell; 10b. Second shell;

[0030] 20a. First drive unit; 21. First rotating shaft; 22. First bushing; 221. First blade; 23. First drive component; 20b. Second drive unit; 24. Second rotating shaft; 25. Second bushing; 251. Second blade; 26. Second drive component;

[0031] 31. First detector; 32. Second detector; 33. Fifth detector; 34. Third detector; 35. Fourth detector;

[0032] 40. Bumper components; 50. Blocking components; 60. Sealing components;

[0033] X, the first direction; Y, the second direction. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] The following is for reference. Figures 1-5 A reaction apparatus 100 for improving the bleaching efficiency of non-silicone hydrogen peroxide stabilizers in chemical mechanical pulp is described according to an embodiment of the first aspect of the present invention.

[0036] like Figure 1 As shown, a reaction apparatus 100 for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers for chemical mechanical pulp according to a first aspect embodiment of the present invention is used for bleaching materials to be bleached. The reaction apparatus 100 includes: a shell 10, a dosing device, a first detector 31, a second detector 32, a third detector 34, and a driving device.

[0037] The shell 10 has an inlet and an outlet. The material to be bleached is adapted to move from the inlet to the outlet of the shell 10 and react chemically with the chemical agent within the shell 10. The shell 10 has a first reaction chamber 11 and a second reaction chamber 12 connected sequentially along the direction of material movement. Specifically, the shell 10 is the main structure of the reaction device, and multiple interconnected reaction chambers for bleaching are formed inside. The arrangement of multiple reaction chambers allows for segmented control of the bleaching process. On the one hand, it allows for precise control of the residence time and reaction conditions of the material in each reaction stage, thereby optimizing the bleaching effect and improving bleaching efficiency. On the other hand, segmented control can effectively prevent over-bleaching or fiber damage caused by excessive reaction time or excessively high agent concentration in a single reaction chamber, thus ensuring the quality stability and consistency of the material to be bleached.

[0038] Specifically, the first reaction chamber 11 includes: a first sub-reaction chamber 111 and a second sub-reaction chamber 112 arranged sequentially in the direction of bleaching material movement. The second sub-reaction chamber 112 includes one or more sub-reaction chambers, and the multiple sub-reaction chambers 112 are arranged sequentially along the direction of bleaching material movement. A first detection area is defined between the first sub-reaction chamber 111 and the second sub-reaction chamber 112, and a second detection area is defined between two adjacent second sub-reaction chambers 112. The housing 10 is also provided with a first dosing port 14 connected to the first sub-reaction chamber 111, a second dosing port 15 and a detection port that correspond one-to-one with and are connected to the second sub-reaction chambers 112, and a discharge port 16 connected to the second reaction chamber 12. Along the direction of bleaching material movement, the detection port is arranged downstream of its corresponding second dosing port 15. The dosing device adds sodium hydroxide solution, non-silicone stabilizer, chelating agent and hydrogen peroxide solution to the first sub-reaction chamber 111 through the first dosing port 14, and adds sodium hydroxide solution to the corresponding second sub-reaction chamber 112 through each second dosing port 15.

[0039] The phrase “a second dosing port 15 and a detection port that correspond one-to-one with and are connected to the second sub-reaction chamber 112” is intended to indicate that each second sub-reaction chamber 112 is connected to a second dosing port 15 and a detection port.

[0040] The first detector 31 is used to detect the pH value of the material to be bleached in the first detection zone; the second detector 32 is located at the detection port and is used to detect the pH value of the material to be bleached in the second sub-reaction chamber 112 after mixing with sodium hydroxide solution; the third detector 34 is used to detect the pH value of the material to be bleached in the second detection zone; the sampling device is used to collect the material to be bleached at the outlet 16 to prepare a test sample; and the whiteness detector is used to detect the whiteness of the test sample.

[0041] Specifically, when bleaching is required for the material to be bleached, the amounts of sodium hydroxide, non-silicone stabilizer, chelating agent, and hydrogen peroxide required for the bleaching process are first calculated based on the amount of material to be bleached. Then, the material to be bleached is fed into the first sub-reaction chamber 111 through the feed inlet 13. Subsequently, sodium hydroxide, non-silicone stabilizer, chelating agent, and hydrogen peroxide solution are added to the first sub-reaction chamber 111 through the first dosing port 14. After the material to be bleached mixes with the added chemical agents in the first sub-reaction chamber 111 and reacts for a period of time, under the action of the driving device, the material to be bleached flows towards the second sub-reaction chamber 112. When the material flows through the first detection zone, the first detector 31 will detect its pH value in real time. At this time, the pH value can be determined manually or by the control device. If the pH value is below 11.5, sodium hydroxide solution is added through the second dosing port 15 to adjust the pH value in the second sub-reaction chamber 112 (i.e., the detection value of the second detector 32) to around 12. If the sodium hydroxide solution is not completely added, the bleaching material will flow to the next second sub-reaction chamber 112 under the action of the drive device after reacting in the second sub-reaction chamber 112 for a certain period of time. When the material flows through the second detection zone, the third detector 34 will detect its pH value in real time and determine again whether the pH value is below 11.5. If it is below 11.5, sodium hydroxide solution is added through the second dosing port 15 on the corresponding second sub-reaction chamber 112 until the sodium hydroxide solution is completely added. Subsequently, the material that has been mixed and reacted in the second sub-reaction chamber 112 flows into the second reaction chamber 12 for deep reaction. After reacting for a period of time, the slurry is discharged.

[0042] Therefore, the setup of multiple detectors and at least one second sub-reaction chamber 112 enables real-time monitoring and dynamic adjustment of the pH of the material to be bleached throughout the entire reaction process, ensuring that the pH value of the material to be bleached is stably maintained within a suitable range of 11.3 to 11.8. It should be noted that hydrogen peroxide achieves its optimal effect, i.e., the bleaching effect is best, at a pH value of around 11.5.

[0043] Furthermore, the statement that "the dosing device adds sodium hydroxide solution, non-silicone stabilizer, chelating agent and hydrogen peroxide solution to the first sub-reaction chamber 111 through the first dosing port 14" is intended to illustrate that this embodiment uses a non-silicone bleaching process to bleach the material to be bleached.

[0044] It should be noted that in existing technologies, sodium silicate can stabilize the system at a buffer pH of around 11.5. Therefore, sodium silicate is generally used as an additive in bleaching processes. However, the addition of sodium silicate is very easy to combine with calcium, magnesium, iron and other ions in the system to form precipitates, which adhere to the surface of the equipment and affect the operating efficiency of filtration equipment such as multi-disc filters and pressure screens, forcing the production line to be shut down for treatment. Moreover, the bleaching of pulp currently mostly uses traditional bleaching reaction chambers, in which all the required chemicals are added at once before the chamber is opened, stirred evenly, and left in the reaction chamber for one hour before being discharged. This makes the bleaching environment uncontrollable throughout the reaction process, resulting in relatively low whiteness of the bleached pulp.

[0045] In this embodiment, a non-silicone bleaching process is used to bleach the material to be bleached. By setting up multiple detectors and at least one second sub-reaction chamber 112, the bleaching environment and pH value can be controlled in the non-silicone bleaching process. This allows the pH environment to be maintained in a good bleaching environment even when using non-silicone stabilizers, thereby further improving the bleaching effect and bleaching uniformity, and reducing the ineffective consumption of chemical agents.

[0046] In addition, by setting multiple discharge ports 16, it is possible to continuously collect slurry samples with different reaction times in the deep reaction section from multiple points, so as to determine in time whether the material has reached the qualified whiteness standard, thereby effectively preventing under-bleaching or over-bleaching problems, and thus improving the quality of the bleached product.

[0047] Optionally, there are multiple first detectors 31, which are arranged at intervals along the outer peripheral surface of the housing 10, and all of the multiple first detectors 31 are used to detect the pH value of the first detection area; there are multiple second detectors 32, which are arranged at intervals along the outer peripheral surface of the housing 10, and all of the multiple second detectors 32 are used to detect the pH value of the same detection area of ​​the second sub-reaction chamber 112; there are multiple third detectors 34, which are arranged at intervals along the outer peripheral surface of the housing 10, and all of the multiple third detectors 34 are used to detect the pH value of the second detection area.

[0048] The reaction apparatus 100 includes a driving device for driving the material to be bleached from the inlet end of the shell 10 toward the outlet end of the shell 10. That is, the driving device provides driving force for the movement of the material to be bleached.

[0049] Optionally, the first dosing port 14 includes a first sub-dosing port 141 and a second sub-dosing port 142. In the direction of movement of the bleaching material, the second sub-dosing port 142 is arranged downstream of the first sub-dosing port 141. The dosing device adds sodium hydroxide solution, non-silicone stabilizer and chelating agent to the first sub-reaction chamber 111 through the feed port of the first sub-dosing port 141; and adds hydrogen peroxide solution to the first sub-reaction chamber 111 through the second sub-dosing port 142.

[0050] Optionally, the housing 10 is also provided with a feed inlet 13 for feeding materials, which is arranged upstream of the first dosing port 14 in the direction of movement of the bleaching material.

[0051] According to the reaction apparatus 100 of the present invention, by setting up multiple detectors and at least one second sub-reaction chamber 112, real-time monitoring and dynamic adjustment of pH value during the bleaching process can be realized, so that the pH value of the material is always maintained in the suitable range of 11.2 to 11.8 throughout the bleaching process, effectively making up for the deficiencies of non-silicone stabilizers in pH adjustment capability, and significantly improving the reaction efficiency, bleaching effect and bleaching uniformity of non-silicone bleaching process.

[0052] According to some embodiments of the present invention, such as Figures 1-2 As shown, the second reaction chamber 12 includes a third sub-reaction chamber 121 and a fourth sub-reaction chamber 122 that are connected sequentially in the direction of bleaching material movement. The third sub-reaction chamber is used for the material to be bleached to react with the chemical agent for a target duration. The discharge port 16 is connected to the fourth sub-reaction chamber 122. In the direction of bleaching material movement, the length of the fourth sub-reaction chamber 122 is less than the length of the third reaction chamber 121.

[0053] The statement that "the length of the fourth sub-reaction chamber 122 is less than the length of the third sub-reaction chamber 121" is intended to indicate that the reaction time of the material to be bleached in the third sub-reaction chamber 121 is longer than the reaction time in the fourth sub-reaction chamber 122.

[0054] Specifically, the third sub-reaction chamber 121 forms the core deep reaction zone, providing sufficient bleaching reaction time for the slurry to ensure adequate reaction between the slurry and the reagents, completing the main bleaching process. The fourth sub-reaction chamber 122 is a supplementary bleaching section, mainly used to extend the reaction time when the whiteness of the slurry inside the third sub-reaction chamber 121 does not meet the standard. In other words, when the whiteness of the slurry inside the third sub-reaction chamber 121 reaches the qualified standard ahead of schedule, the material can be directly discharged through the outlet 16 located in the third sub-reaction chamber 121 without entering the subsequent fourth sub-reaction chamber 122; while when the material to be bleached does not meet the standard, the bleaching material continues to flow into the shorter fourth sub-reaction chamber 122 for a short-term fine stabilization reaction.

[0055] Since the reaction time in the fourth sub-reaction chamber 122 is shorter than that in the third sub-reaction chamber 121, the problem of over-bleaching caused by prolonged slurry retention can be effectively avoided. This can effectively prevent defects such as reduced slurry quality and strength caused by over-bleaching, thereby improving the uniformity of slurry bleaching and the consistency of finished product whiteness.

[0056] It should be noted that there is one or more third sub-reaction chambers 121 and fourth sub-reaction chambers 122.

[0057] According to some embodiments of the present invention, such as Figures 1-2 As shown, there are multiple fourth sub-reaction chambers 122, which are arranged sequentially along the direction of bleaching material movement. Each fourth sub-reaction chamber 122 is provided with a discharge port 16. The reaction device 100 also includes: a fourth detector 35, a sampling device, and a whiteness detector. The fourth detector 35 is used to detect the pH value of the material to be bleached at the discharge port 16. The sampling device is used to collect the material to be bleached at the discharge port 16 to prepare a test sample. The whiteness detector is used to detect the whiteness of the test sample.

[0058] Specifically, the sampling device is mainly used to extract the bleachable material from the fourth sub-reaction chamber through multiple outlets 16 after the material flows into the third sub-reaction chamber 121 for a period of time for deep reaction, and prepare it into a test sample. The whiteness detector is mainly used to detect the whiteness of the sample to confirm whether the bleaching effect meets the standard: if it meets the requirements, the machine is stopped and the material is discharged; if it does not meet the standard, the reaction continues until it meets the standard. The fourth detector 35 is mainly used to confirm the pH of the bleachable material after the reaction in the third sub-reaction chamber 121 when the whiteness does not meet the standard. For example, when the whiteness does not meet the requirements and the pH value is greater than 9, the material is temporarily not discharged and continues to enter the next fourth sub-reaction chamber 122 for reaction until the whiteness meets the standard. If the whiteness does not meet the standard and the pH value is less than 9, it indicates that the amount of medicine calculated at the front end is incorrect. In this way, the control system can upload the deviation data of pH and whiteness to the control unit or feed it back to the staff, so that the staff can adjust the dosage of medicine for the next batch, thereby improving the pass rate of the next batch of bleaching.

[0059] Therefore, this embodiment, through the setting of multiple discharge ports 16, can continuously collect slurry samples of different reaction times within the deep reaction section at multiple points, thereby promptly determining whether the material has reached the qualified whiteness standard, effectively preventing under-bleaching or over-bleaching problems, and thus improving the quality of the bleached product; the setting of the fourth detector 35 enables refined grading of materials that do not meet the whiteness standard, breaking the one-sidedness of relying solely on whiteness data to determine the reaction endpoint in the traditional way. Through the linkage verification of pH and whiteness dual parameters, it accurately distinguishes different causes of under-bleaching of materials and matches corresponding optimized control schemes, thereby significantly improving the whiteness qualification rate and batch quality stability of the final product, while effectively avoiding reagent waste and excessive fiber damage caused by blindly adding chemicals.

[0060] Optional, such as Figures 1-2 As shown, the reaction apparatus 100 also includes a fifth detector 33, which is used to detect the pH value of the third sub-reaction chamber 121.

[0061] According to some specific embodiments of the present invention, the dosing device further includes: a first dosing tank, a second dosing tank, a third dosing tank, and a fourth dosing tank. The first dosing tank is used to store a non-silicone stabilizer. The first dosing tank is connected to a first dosing port 14 via a first dosing pipe, and a first dosing pump for pumping the non-silicone stabilizer is connected in series on the first dosing pipe. The second dosing tank is used to store a chelating agent. The second dosing tank is connected to the first dosing port 14 via a second dosing pipe, and a second dosing pump for pumping the chelating agent solution is connected in series on the second dosing pipe. The third dosing tank is used to store a sodium hydroxide solution. The third dosing tank is connected to the first dosing port 14 and a second dosing port 15 via a third dosing pipe, and a third dosing pump for pumping the sodium hydroxide solution is connected in series on the third dosing pipe. The fourth dosing tank is used to store a hydrogen peroxide solution. The fourth dosing tank is connected to the first dosing port 14 via a fourth dosing pipe, and a fourth dosing pump for pumping the hydrogen peroxide solution is connected in series on the fourth dosing pipe.

[0062] It is understood that the addition of reagents in this embodiment is controlled by a dosing pump. This can further improve the automation of the reaction device 100, improve the accuracy of reagent addition, and thus improve the bleaching pass rate. In addition, the setting of multiple dosing tanks can also ensure that the storage of multiple reagents does not affect each other, thereby avoiding the mixing reaction between different reagents, ensuring the purity of various reagents, and stabilizing the reagent dosing accuracy of the bleaching reaction.

[0063] According to some specific embodiments of the present invention, the reaction apparatus 100 further includes a control device, which is electrically connected to a whiteness detector, a sampling device, a first detector 31, a second detector 32, a third detector 34, a fourth detector 35, and the aforementioned plurality of dosing pumps.

[0064] It is understood that this embodiment can construct a complete closed-loop automatic control system through the setting of the control device, so that the reaction device 100 of this application can automatically acquire core parameters such as pH value and slurry whiteness of the reaction system, and control the start and stop of the dosing pump, the delivery flow rate and the dosing time through these parameters, so as to realize automated and precise dosing and dosing on demand. In this way, it can solve the defects of traditional bleaching process, such as excessive or insufficient dosage, delayed dosing and incomplete dosing caused by manual dosing based on experience. It can ensure accurate reagent ratio in each reaction chamber and full reaction between reagent and slurry, and ensure a stable bleaching reaction environment throughout the process. In this way, it can effectively avoid problems such as bleaching fluctuations, uneven product whiteness and batch quality differences caused by reagent imbalance, and further improve the automation level, reaction stability and finished product qualification rate of the bleaching process.

[0065] According to some embodiments of the present invention, such as Figures 1-2 As shown, the housing 10 includes: a first housing 10a and a second housing 10b. The first housing 10a extends along a first direction, and a first reaction chamber 11 is disposed within the first housing 10a. The second housing 10b extends along the first direction and is spaced apart from the first housing 10a in the second direction Y. A second reaction chamber 12 is disposed within the second housing 10b. The first housing 10a and the second housing 10b are connected.

[0066] It is understood that the housing 10 in this embodiment includes two sections, which are arranged side by side or staggered. This reduces the space occupied in the length direction of the housing 10, thereby reducing the floor area of ​​the entire bleaching device.

[0067] It should be noted that the second direction Y can be either up and down or left and right; there are no restrictions here.

[0068] For example, the second direction Y is the up-down direction, and the second housing 10b is arranged below the first housing 10a. In this way, the material can automatically fall into the second housing 10b under gravity, thereby reducing the use of driving equipment and thus reducing the production cost of the entire device.

[0069] According to some embodiments of the present invention, such as Figures 1-2 As shown, the driving device includes: a first driving device 20a and a second driving device 20b. The first driving device 20a is used to drive the material to be bleached in the first housing 10a to move along a first direction; the second driving device 20b is used to drive the material to be bleached in the second housing 10b to move along the first direction.

[0070] It is understandable that the first shell 10a and the second shell 10b are each equipped with a corresponding drive device. This allows the material conveying and reaction processes in the two shells 10 to be controlled independently without interference. At the same time, the dual-drive configuration also facilitates the differentiated adjustment of the stirring intensity, filling rate and residence time in the two shells 10 to adapt to the fluctuations in whiteness and concentration of different batches of materials, thereby improving the flexibility and control precision of the overall process.

[0071] According to some embodiments of the present invention, such as Figures 1-2 As shown, the first driving device 20a includes: a first rotating shaft 21, a first bushing 22, and a first driving member 23. The first rotating shaft 21 extends along the first direction X and is arranged inside the first housing 10a. The axis of the first rotating shaft 21 coincides with the axis of the first housing 10a. The first bushing 22 is sleeved on the outside of the first rotating shaft 21. The first blade 221 extends spirally along the axial direction of the first rotating shaft 21 on the outside of the first bushing 22. The first driving member 23 is connected to one end of the first rotating shaft 21 and is used to drive the first rotating shaft 21 to rotate, so as to drive the material to be bleached to move along the first direction X.

[0072] Specifically, the first driving component 23 is mainly connected to the end of the first rotating shaft 21, providing rotational power to the first rotating shaft 21. The first rotating shaft 21, as the core transmission component, converts its rotational motion into the propulsive force of the blades, thereby driving the material to move along the first direction X (i.e. from the feed inlet 13 to the discharge outlet 16).

[0073] In this embodiment, the axis of the first rotating shaft 21 is aligned with the axis of the first housing 10a. This ensures the dynamic balance of the rotating components, reduces vibration and noise caused by eccentricity during high-speed rotation of the first rotating shaft 21, and thus extends the service life of the equipment. Simultaneously, the coaxial design allows for more efficient use of the internal space of the first housing 10a, providing a uniform annular reaction channel for the materials. The spiral blades not only serve a conveying function but also a mixing function, enhancing the contact efficiency between the materials and chemical agents. This improves the uniformity and thoroughness of the bleaching reaction, effectively solving the problem of poor bleaching results caused by poor material conveying or uneven mixing in traditional equipment.

[0074] Optionally, there may be multiple first bushings 22, which are arranged at intervals along the first direction X, with each first bushing 22 corresponding to a specific number of reaction chambers. This allows the first bushings 22 to be structurally designed specifically for the independent operating conditions of each reaction chamber, enabling them to adapt to the different material conveying speeds and reaction times of each chamber.

[0075] According to some embodiments of the invention, for example Figures 1-2As shown, the second driving device 20b includes: a second rotating shaft 24, a second bushing 25, and a second driving member 26. The second rotating shaft 24 extends along the first direction X and is arranged inside the second housing 10b. The axis of the second rotating shaft 24 coincides with the axis of the second housing 10b. The second bushing 25 is sleeved on the outside of the second rotating shaft 24. The second blade 251 extends spirally along the axial direction of the second rotating shaft 24 on the outside of the second bushing 25. The second driving member 26 is connected to one end of the second rotating shaft 24 and is used to drive the second rotating shaft 24 to rotate, so as to drive the material to be bleached to move along the second direction Y.

[0076] It is understandable that the second drive unit 20b has the same structure as the first drive unit 20a, which simplifies the training of on-site operators and the maintenance process.

[0077] It should be noted that the rotational speeds of the first drive component 23 and the second drive component 26 during operation can be the same or different. The dimensions of the first bushing 22 and the second bushing 25 and the spacing between the externally mounted blades can be the same or different; no restrictions are imposed here.

[0078] According to some embodiments of the present invention, such as Figures 1-2 As shown, at least one steam inlet 17 is formed on the sidewall of the first reaction chamber 11 and the second reaction chamber 12. The reaction device 100 also includes an air inlet pipe, one end of which is connected to the steam inlet 17, and the other end is adapted to be connected to an external steam source. In this way, the processing temperature during the bleaching process can be stably maintained within the process setting range, thereby providing suitable temperature activation conditions for the hydrogen peroxide bleaching reaction, improving the reactivity of the reagent, accelerating the reaction rate between the slurry and the chemical reagent, and shortening the overall bleaching time. At the same time, it can also be combined with pH adjustment to optimize the reaction environment, thereby effectively improving the reagent utilization rate and reducing the ineffective loss of reagent, thus ensuring the uniformity of material bleaching and the consistency of finished product whiteness.

[0079] According to some specific embodiments of the present invention, the reaction apparatus 100 further includes: a plurality of temperature detectors, which are arranged at intervals along a first direction X on the housing 10 for real-time detection of the temperature in the first reaction chamber 11 and the second reaction chamber 12. Specifically, the arrangement of multiple temperature detectors enables segmented online temperature monitoring throughout the bleaching process. This allows for precise control of the temperature conditions of the primary reaction section and the deep reaction section, thereby enabling precise control of the reaction temperature within the reaction chamber and further improving the uniformity of material bleaching and the consistency of finished product whiteness.

[0080] According to some embodiments of the present invention, such as Figures 1-2 As shown, according to some embodiments of the present invention, such as Figures 1-2As shown, the reaction apparatus 100 further includes a flow-deflecting element 40, which is disposed on at least a portion of the inner wall of the housing 10, and on at least a portion of the first blade 221 and a portion of the second blade 251. It is understood that the flow-deflecting element 40 is provided on the first blade 221, the second blade 251, and the inner wall of the housing 10. The flow-deflecting element 40 may be provided only on a portion of the inner wall surface of the housing 10, a portion of the first blade 221, and a portion of the second blade 251, or it may be provided on the entire inner wall of the housing 10, on all the first blades 221, and on all the second blades 251. For example, Figures 1-2 As shown, the turbulence-inducing element 40 is only provided in the second sub-reaction chamber 112 and the third sub-reaction chamber 121. The turbulence-inducing element 40 is provided to facilitate the creation of turbulence, thereby improving the mixing between the slurries and thus enhancing the bleaching effect.

[0081] According to some embodiments of the present invention, the reaction apparatus 100 further includes a sealing member 50, which is disposed on the housing 10 and used to open or close the discharge port 16. The sealing member 50 facilitates flexible switching of the on / off states of each discharge port 16, enabling controllable switching between segmented multi-point sampling and material diversion discharge. For example, when the whiteness meets the standard, the corresponding sealing member can be opened for rapid unloading; when the slurry does not meet the standard, the sealing member is closed, allowing the material to continue reacting in the subsequent chambers, preventing the leakage of high-temperature slurry and steam from the chambers. This effectively stabilizes the internal temperature and pH reaction environment of each reaction chamber, preventing fluctuations in operating conditions from affecting the bleaching effect, thereby effectively improving the stability of the bleaching process.

[0082] Optionally, the reaction device 100 further includes a seal 60, which abuts against the plug 50 and the housing 10 to seal the gap between the plug 50 and the housing 10, thereby improving the airtightness of the cavity.

[0083] According to a second aspect of the present invention, a method for use in a reaction apparatus 100 according to a first aspect of the present invention, the method comprises:

[0084] Step S1: Add the material to be bleached into the first reaction chamber 11 through the feed inlet 13;

[0085] Step S2: The first part of sodium hydroxide, accounting for 60% to 75% of the total amount of sodium hydroxide, non-silicon stabilizer, chelating agent and hydrogen peroxide solution are added into the first reaction chamber 11 through the first dosing port 14 to mix with the material to be bleached. At the same time, steam is introduced into the first reaction chamber 11 to make the temperature reach the preset temperature.

[0086] Step S3: Control the reaction time of the material to be bleached in the first sub-reaction chamber 111 to reach the first preset time.

[0087] Step S4: Confirm whether the pH value of the first detection area meets the first preset value. If the pH value is lower than the first preset value, execute the first strategy. If the pH value is not lower than the first preset value, execute the second strategy.

[0088] The first strategy includes: adding sodium hydroxide solution to the second sub-reaction chamber 112 through the second dosing port 15 to make the pH value reach a second preset value, which is greater than the first preset value; controlling the reaction time of the material to be bleached in the second sub-reaction chamber 112 to reach a second preset duration; confirming whether the pH value of the second detection zone meets the first preset value; if the pH value is lower than the first preset value, repeating the first strategy until the total amount of sodium hydroxide has been added; if the pH value is not lower than the first preset value, executing the second strategy.

[0089] The second strategy includes: controlling the reaction time of the material to be bleached in the second sub-reaction chamber 112 to reach the second preset time, confirming whether the pH value of the second detection zone meets the first preset value, if the pH value is lower than the first preset value, repeating the first strategy until the total amount of sodium hydroxide is added, and if the pH value is not lower than the first preset value, executing the second strategy.

[0090] Step S5: Control the reaction time of the material to be bleached in the third sub-reaction chamber 121 to reach the target duration, and obtain the bleached material;

[0091] Step S6: Detect the whiteness of the bleached material and confirm whether the whiteness reaches the preset whiteness value. If the whiteness reaches the preset whiteness value, execute the third strategy; if the whiteness is lower than the preset whiteness value, execute the fourth strategy.

[0092] The third strategy includes discharging the bleached material through outlet 16;

[0093] The fourth strategy includes: confirming whether the pH of the bleaching material is higher than the third preset value; if so, after the bleaching material enters the fourth sub-reaction chamber 122 and continues to react for the second preset time, confirming whether the whiteness at the outlet 16 reaches the preset whiteness value; if the whiteness reaches the preset whiteness value, execute the third strategy; if the whiteness does not reach the preset whiteness value, execute the fourth strategy until the whiteness reaches the preset whiteness value; if not, discharge the bleaching material through the outlet 16 and add hydrogen peroxide solution to the first sub-reaction chamber 111 through the first dosing port 14, and then repeat steps S3-S6 until the whiteness reaches the preset whiteness value.

[0094] Specifically, the first preset value is 11.2-11.8, the second preset value is 12, the third preset value is 9, the whiteness value is 75%ISO-81%ISO, the first preset duration is 15min-20min; the target duration is 30min, and the third preset duration is 10min-20min.

[0095] For example, when bleaching is required, the feed rate of the material to be bleached and the dosage of chemicals are first set on the control device panel. Then, a fixed amount of the material to be bleached is added to the first sub-reaction chamber 111 through the feed inlet 13 by a screw feeder. The control device then calculates the total amount of sodium hydroxide, non-silicon stabilizer, chelating agent, and hydrogen peroxide to be added based on the amount of the material to be bleached, and issues dosing commands to the first, second, third, and fourth dosing pumps. Based on a dosing command, a first dosing pump, a second dosing pump, and a third dosing pump add a first portion of sodium hydroxide (60%–75% of the total sodium hydroxide content), a non-silicon stabilizer, and a chelating agent through a first sub-dosing port 141 to the first sub-reaction chamber 111 to mix with the material to be bleached. Based on a dosing command, a fourth dosing pump adds hydrogen peroxide reagent through a second sub-dosing port 142 to the first sub-reaction chamber 111 to mix with the material to be bleached. At the same time, steam is introduced into the first sub-reaction chamber 111 to maintain the temperature required for bleaching.

[0096] Then, the rotational speed of the first shaft is controlled by controlling the rotational speed of the first driving component, so that the reaction time of the material to be bleached in the first sub-reaction chamber 111 reaches 15-20 minutes. Afterwards, the pH value of the material to be bleached after reaction in the first sub-reaction chamber 111 is detected by the first detector 31. If the pH value is lower than 11.3, sodium hydroxide is added through the second dosing port 15. The amount of sodium hydroxide added is based on the value detected by the first detector 31, so that the pH value detected by the second detector 32 reaches 12.0, thus controlling the reaction time of the material to be bleached. The reaction time in the second sub-reaction chamber 112 reaches 15-20 minutes. It is confirmed whether the pH value of the second detection zone reaches 11.3. If the pH value is lower than 11.3, this step is repeated until all sodium hydroxide is added. If the pH value is higher than 11.3, the reaction continues in the second sub-reaction chamber 112 for the first preset time. It is confirmed whether the pH value of the second detection zone reaches 11.3. If the pH value is lower than 11.3, sodium hydroxide is added through the second dosing port 15 until the total amount of sodium hydroxide is added.

[0097] After the total amount of sodium hydroxide has been added, the rotation speed of the second drive component 26 is controlled to ensure that the reaction time of the material in the third sub-reaction chamber 121 is at least 30 minutes after the addition of sodium hydroxide. When the processing time reaches 30 minutes, the sampling device takes a sample through the discharge port 16, which is connected to the fourth sub-reaction chamber 122, and performs whiteness detection using a whiteness detector, comparing it with a preset whiteness value. When the whiteness of the slurry meets the process requirements, the bleached material is directly discharged through the discharge port 16; otherwise, it is discharged. The pH at the discharge port 16 is then measured using the fourth detector 35. If the pH value is greater than 9, the material is temporarily withheld and continues to the next fourth sub-reaction chamber 122 until the whiteness meets the standard. If the whiteness does not meet the standard and the pH value is less than 9, it indicates that hydrogen peroxide needs to be added to the front end. In this case, the discharge port 16 is opened to discharge the internal slurry. At the same time, hydrogen peroxide solution is added to the first sub-reaction chamber 111 through the second sub-dosing port 142 to adjust the amount of hydrogen peroxide in the entire reaction chamber to ensure the subsequent bleaching effect. It should be noted that the amount of addition can be selected according to the actual situation. For example, the amount of addition can be 5% of the initial addition amount, and there is no limit here.

[0098] According to the method of the present invention, by monitoring the pH value and whiteness of the slurry throughout the process, the deficiency of non-silicone stabilizers in pH adjustment can be effectively compensated, thereby effectively improving the reaction efficiency of the non-silicone bleaching process. At the same time, under the same chemical dosage, the whiteness of the bleached slurry treated by this process can reach a level comparable to that of the traditional sodium silicate process, thus ensuring the bleaching quality. In addition, the method has strong automation and controllability, which can reduce unnecessary consumption of bleaching agents and can be adapted to various slurry conditions. Therefore, it is applicable to the promotion and application of non-silicone bleaching processes in large-scale mechanical pulp production lines.

[0099] The following will refer to Figures 1-5 The present application describes a reaction apparatus 100 according to two specific embodiments.

[0100] Reference Figure 1 The reaction device 100 includes: a shell 10, a first detector 31, a second detector 32, a third detector 34, a fourth detector, a sampling device, a whiteness detector, and a driving device.

[0101] The shell 10 extends along the first direction X and has an inlet end and an outlet end. The shell 10 is provided with multiple reaction chambers, which are arranged between the inlet end and the outlet end. The material to be bleached is suitable to move from the inlet end of the shell 10 toward the outlet end of the shell 10 and react with chemical agents in the reaction chambers. The multiple reaction chambers include a first reaction chamber 11 and a second reaction chamber 12 that are connected in sequence along the direction of movement of the bleaching material.

[0102] Specifically, the housing 10 includes: a first housing 10a and a second housing 10b, both of which extend along a first direction X. A first reaction chamber 11 is disposed in the first housing 10a, and a second reaction chamber 12 is disposed in the second housing 10b. The second housing 10b is arranged below the first housing 10a, and the first housing 10a and the second housing 10b are connected.

[0103] The first reaction chamber 11 includes: a first sub-reaction chamber 111 and a second sub-reaction chamber 112 arranged sequentially in the direction of movement of the bleaching material. There are two second sub-reaction chambers 112, which are arranged sequentially along the direction of movement of the bleaching material. A first detection area is defined between the first sub-reaction chamber 111 and the second sub-reaction chamber 112, and a second detection area is defined between two adjacent second sub-reaction chambers 112.

[0104] The second reaction chamber 12 includes a third sub-reaction chamber 121 and two fourth sub-reaction chambers 122. Each fourth sub-reaction chamber 122 has a discharge port 16. The discharge ports 16 are respectively arranged at the end of each fourth sub-reaction chamber 122. In the first direction X, the fourth sub-reaction chamber 122 is arranged on the side of the third sub-reaction chamber 121 away from the first reaction chamber 11. The length of the fourth sub-reaction chamber 122 is less than the length of the third sub-reaction chamber 121.

[0105] The housing 10 is also provided with a feed inlet 13, a first sub-dosing port 141, a second sub-dosing port 142, a second sub-dosing port 15, a detection port, and at least one discharge port 16. The feed inlet 13, the first sub-dosing port 141, and the second sub-dosing port 142 are all connected to the first sub-reaction chamber 111. In the direction of bleaching material movement, the first sub-dosing port 141 is located downstream of the feed inlet 13 and is used to add sodium hydroxide solution, non-silicone stabilizers, and chelating agents to the first sub-reaction chamber 111. The second sub-dosing port 142... 42 is arranged downstream of the first sub-dosing port 141 for adding hydrogen peroxide solution to the first sub-reaction chamber 111. The second dosing port 15 and the detection port are both connected to the second sub-reaction chamber 112. The second dosing port 15 is arranged upstream of the detection port and is used to add sodium hydroxide solution to the second sub-reaction chamber 112. The discharge port 16 is connected to the second reaction chamber 12, and multiple discharge ports 16 are arranged sequentially along the moving direction of the material to be bleached.

[0106] The first detector 31 is used to detect the pH value of the material to be bleached in the first detection zone; the second detector 32 is located at the detection port and is used to detect the pH value of the material to be bleached in the second sub-reaction chamber 112 after mixing with sodium hydroxide solution; the third detector 34 is used to detect the pH value of the material to be bleached in the second detection zone; the sampling device is used to collect the material to be bleached at the outlet 16 to prepare a test sample; the whiteness detector is used to detect the whiteness of the test sample; and the fourth detector 35 is used to detect the pH value of the material to be bleached at the outlet 16.

[0107] The reaction apparatus 100 includes a driving device, which includes a first driving device 20a and a second driving device 20b. The first driving device 20a is used to drive the material to be bleached in the first housing 10a to move along a first direction; the second driving device 20b is used to drive the material to be bleached in the second housing 10b to move along the first direction.

[0108] Specifically, the first driving device 20a includes: a first rotating shaft 21, a first bushing 22, and a first driving member 23. The first rotating shaft 21 extends along the first direction X and is arranged inside the first housing 10a. The axis of the first rotating shaft 21 coincides with the axis of the first housing 10a. The first bushing 22 is sleeved on the outside of the first rotating shaft 21. The first blade 221 extends spirally along the axial direction of the first rotating shaft 21 on the outside of the first bushing 22. The first driving member 23 is connected to one end of the first rotating shaft 21 and is used to drive the first rotating shaft 21 to rotate, so as to drive the material to be bleached to move along the first direction X.

[0109] The second drive device 20b includes a second rotating shaft 24, a second bushing 25, and a second drive member 26. The second rotating shaft 24 extends along a first direction X and is arranged inside the second housing 10b. The axis of the second rotating shaft 24 coincides with the axis of the second housing 10b. The second bushing 25 is sleeved on the outside of the second rotating shaft 24, and a second blade 251 extending spirally along the axial direction of the second rotating shaft 24 is provided on the outside of the second bushing 25. The second drive member 26 is connected to one end of the second rotating shaft 24 and is used to drive the second rotating shaft 24 to rotate so as to drive the material to be bleached to move along the first direction X.

[0110] Further, the dosing device includes: a first dosing tank, a second dosing tank, a third dosing tank, and a fourth dosing tank. The first dosing tank is used to store non-silicone stabilizers. The first dosing tank is connected to a first sub-dosing port 141 via a first dosing pipe. A first dosing pump for pumping non-silicone stabilizers is connected in series on the first dosing pipe. The second dosing tank is used to store chelating agents. The second dosing tank is connected to the first sub-dosing port 141 via a second dosing pipe. A second dosing pump for pumping chelating agent solution is connected in series on the second dosing pipe. The third dosing tank is used to store sodium hydroxide solution. The third dosing tank is connected to the first sub-dosing port 141 and the second dosing port 15 via a third dosing pipe. A third dosing pump for pumping sodium hydroxide solution is connected in series on the third dosing pipe. The fourth dosing tank is used to store hydrogen peroxide solution. The fourth dosing tank is connected to the second sub-dosing port 142 via a fourth dosing pipe. A fourth dosing pump for pumping hydrogen peroxide solution is connected in series on the fourth dosing pipe.

[0111] The reaction apparatus also includes a control device, which is electrically connected to a whiteness detector, a sampling device, a first detector 31, a second detector 32, a third detector 34, a fourth detector 35, and the aforementioned multiple dosing pumps.

[0112] Furthermore, at least one steam inlet 17 is formed on the sidewall of the first reaction chamber 11 and the second reaction chamber 12. The reaction device 100 also includes an air inlet pipe and a plurality of temperature detectors, wherein one end of the air inlet pipe is connected to the steam inlet 17 and the other end is adapted to be connected to an external high-temperature steam source. The plurality of temperature detectors are arranged at intervals along the first direction X on the housing 10 for real-time detection of the temperature in the first reaction chamber 11 and the second reaction chamber 12.

[0113] The reaction device 100 also includes a flow-disrupting element 40 and a sealing element 50. The flow-disrupting element 40 is disposed on the side walls of the second sub-reaction chamber and the third sub-reaction chamber, and on the blades disposed in the second sub-reaction chamber and the third sub-reaction chamber 121. The sealing element 50 is disposed on the housing 10 and is used to open or cover the discharge port 16.

[0114] One method is described below.

[0115] When bleaching is required, the feed rate of the material to be bleached and the dosage of chemicals are first set on the control panel. Then, a fixed amount of the material to be bleached is added into the first reaction chamber 1111 through the feed inlet 13 by a screw feeder. The control device then calculates the total amount of sodium hydroxide, non-silicone stabilizer, chelating agent, and hydrogen peroxide to be added based on the amount of the material to be bleached, and issues dosing commands to the first, second, third, and fourth dosing pumps. Based on a dosing command, the first pump, the second dosing pump, and the third dosing pump add a first portion of sodium hydroxide (60%–75% of the total sodium hydroxide content), a non-silicon stabilizer, and a chelating agent to the first sub-reaction chamber 111 through the first sub-dosing port 141 to mix with the material to be bleached. Based on a dosing command, the fourth dosing pump adds hydrogen peroxide to the first sub-reaction chamber 111 through the second sub-dosing port 142 to mix with the material to be bleached. At the same time, steam is introduced into the first sub-reaction chamber 111 to maintain the temperature required for bleaching.

[0116] Then, the rotational speed of the first shaft 21 is controlled by controlling the rotational speed of the first driving component 23, so that the reaction time of the material to be bleached in the first sub-reaction chamber 111 reaches 15-20 minutes. Then, the pH value of the material to be bleached after reaction in the first sub-reaction chamber 111 is detected by the first detector 31. If the pH value is lower than 11.3, sodium hydroxide is added through the second dosing port 15. The amount of sodium hydroxide added is based on the value detected by the first detector 31, so that the pH value detected by the second detector 32 reaches 12.0, thus controlling the bleaching process. The reaction time of the white material in the second sub-reaction chamber 112 reaches 15-20 minutes. Check whether the pH value of the second detection zone reaches 11.3. If the pH value is lower than 11.3, repeat this step until all sodium hydroxide is added. If the pH value is higher than 11.3, continue to enter the second sub-reaction chamber 112 for the first preset reaction time. Check whether the pH value of the second detection zone reaches 11.3. If the pH value is lower than 11.3, add sodium hydroxide through the second dosing port 15 until the total amount of sodium hydroxide is added.

[0117] After the total amount of sodium hydroxide has been added, the rotation speed of the second drive unit 26 is controlled to ensure that the reaction time of the material in the third sub-reaction chamber 121 is at least 30 minutes after the sodium hydroxide is added. When the processing time reaches 30 minutes, the sampling device takes a sample through the discharge port 16, which is connected to the fourth sub-reaction chamber 122, and performs whiteness detection using a whiteness detector, comparing it with the preset whiteness value. When the whiteness of the slurry meets the process requirements, the bleached material is directly discharged through the discharge port 16. If the requirements are not met, the whiteness is detected by the fourth detector 35. If the pH value at the discharge port 16 is greater than 9, the material is temporarily withheld and continues to enter the next fourth sub-reaction chamber 122 for reaction until the whiteness meets the standard. If the whiteness does not meet the standard and the pH value is less than 9, it indicates that sodium hydroxide needs to be added at the front end. At this time, the discharge port 16 is opened to discharge the internal slurry. At the same time, the control device calculates the amount of sodium hydroxide to be added based on the difference between the pH value and the third preset value, and adds it to the first sub-reaction chamber 111 through the second sub-dosing port 142 to adjust the amount of sodium hydroxide in the entire reaction chamber to ensure the subsequent bleaching effect.

[0118] According to the method of the present invention, by monitoring the pH value and whiteness of the slurry throughout the process, the deficiency of non-silicone stabilizers in pH adjustment can be effectively compensated, thereby effectively improving the reaction efficiency of the non-silicone bleaching process. At the same time, under the same chemical dosage, the whiteness of the bleached slurry treated by this process can reach a level comparable to that of the traditional sodium silicate process, thus ensuring the bleaching quality. In addition, the method has strong automation and controllability, which can reduce unnecessary consumption of bleaching agents and can be adapted to various slurry conditions. Therefore, it is applicable to the promotion and application of non-silicone bleaching processes in large-scale mechanical pulp production lines.

[0119] The following is a brief description of Comparative Example 1 and Comparative Example 2, which are used as comparative examples to compare with Embodiment 1 of this application.

[0120] Among them, the material to be bleached is eucalyptus mechanical pulp, which is made from unbleached eucalyptus (Guangxi) chemimechanical pulp, and the experiment is carried out according to the process conditions in Table 1.

[0121] Comparative Examples 1 and 2 both used traditional bleaching reaction chambers. All required chemicals were added at once before entering the chamber, stirred thoroughly, and then left to stand in the chamber for one hour before being discharged. Example 1 used the aforementioned reaction apparatus 100. In the first reaction chamber 11, 80 kg / t of odt pulp hydrogen peroxide, 24.5 kg / t of sodium hydroxide (70% of the total amount), 5 kg / t of commercially available eucalyptus-based non-silicone stabilizer (Yixing Fengze Chemical Co., Ltd. 60114P), and 5 kg / t of DTPA chelating agent were added. By adjusting the rotation speed of the first rotating shaft 21, the residence time of the slurry in the first reaction chamber 11 was ensured to be 15-20 minutes. When the slurry entered the second sub-reaction chamber 112, the first detector 31 read a pH of 11.2. At this point, 6 kg / t of sodium hydroxide was added, and the second detector 32 read a pH of 12.0. When the slurry enters the second sub-reaction chamber 112, the fourth detector 35 reads a pH of 11.0. At this point, the remaining 4.5 kg / t of sodium hydroxide is added, and the second detector 32 reads a pH of 11.7. The slurry then enters the third sub-reaction chamber 121 for further reaction. After reacting in the third sub-reaction chamber 121, the whiteness of the slurry, as measured by the whiteness detector, is 76.7% ISO, and the pH is 8.08. Discharging is then selected to end the reaction.

[0122] Collect the pulp from the three experiments separately, pour them into 1L of distilled water, stir thoroughly, and then wash the pulp with distilled water using a vacuum filtration apparatus in a Buchner funnel lined with filter cloth until the pH of the filtrate is 7.0±0.5. Measure the pulp whiteness according to GB / T 7974-2002: (Determination of brightness (whiteness) of paper, paperboard and pulp (diffuse / vertical method)).

[0123] Table 1

[0124]

[0125] As can be seen from the above, under the same amount of chemicals, when using a traditional reaction chamber, the whiteness of the pulp obtained by the non-silicone bleaching process is 3.7% ISO lower than that of the sodium silicate process. However, after using the reactor designed in this invention, the whiteness of the pulp obtained by the non-silicone bleaching process is only 0.4% ISO lower than that of the sodium silicate process, and the bleaching effect is significantly improved.

[0126] Example 2,

[0127] This embodiment has a structure that is largely the same as that of Embodiment 1, with the same components using the same reference numerals. The only difference is that in Embodiment 1, there are two second sub-reaction chambers 112 and two fourth sub-reaction chambers 122, while in this Embodiment 2, there are three second sub-reaction chambers 112 and three fourth sub-reaction chambers 122.

[0128] The following is a brief description of Comparative Example 3 and Comparative Example 4, which are used as comparative examples to compare with Embodiment 2 of this application.

[0129] Among them, the material to be bleached: Poplar mechanical pulp was made from unbleached poplar (Shandong) chemimechanical pulp, and the experiment was carried out according to the process conditions in Table 2.

[0130] Comparative Examples 3 and 4 both used traditional bleaching reaction chambers. All required chemicals were added at once before entering the chamber, stirred thoroughly, and then left to stand in the chamber for one hour before being discharged. Example 2 used the reaction apparatus 100 of this application. In the mixing reaction unit, 80 kg / t of odt pulp hydrogen peroxide, 30 kg / t of sodium hydroxide (60% of the total amount), 5 kg / t of commercially available poplar-type non-silicone stabilizer (Guangdong Liangshi Industrial Materials Co., Ltd. WT-3066), and 5 kg / t of DTPA chelating agent were added. Then, following a similar procedure to Example 1, the remaining sodium hydroxide was added to the three second sub-reaction chambers 112.

[0131] Collect the pulp from the three experiments separately, pour them into 1L of distilled water, stir thoroughly, and then wash the pulp with distilled water using a vacuum filtration apparatus in a Buchner funnel lined with filter cloth until the pH of the filtrate is 7.0±0.5. Measure the pulp whiteness according to GB / T 7974-2002: (Determination of brightness (whiteness) of paper, paperboard and pulp (diffuse / vertical method)).

[0132] Table 2

[0133]

[0134] As can be seen from the experimental results in Table 2, when using a traditional reaction chamber, the whiteness of the pulp obtained by the non-silica bleaching process is 4.5% ISO lower than that of the sodium silicate process. However, after using the reactor designed in this invention, the whiteness of the pulp is the same as that of the sodium silicate process under the same chemical dosage, and the bleaching effect is significantly improved.

[0135] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0136] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0137] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0138] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0139] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A reaction apparatus for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulps, used for bleaching materials to be bleached, characterized in that, include: The housing has an inlet end and an outlet end. The material to be bleached is adapted to move from the inlet end of the housing towards the outlet end of the housing and to react chemically with a chemical agent within the housing. The housing contains a first reaction chamber and a second reaction chamber that are sequentially connected along the direction of movement of the bleached material. The first reaction chamber includes a first sub-reaction chamber and a second sub-reaction chamber arranged sequentially along the direction of movement of the bleached material. The second sub-reaction chamber includes one or more sub-reaction chambers arranged sequentially along the direction of movement of the bleached material. A first detection area is defined between the first sub-reaction chamber and the second sub-reaction chamber, and a second detection area is defined between two adjacent second sub-reaction chambers. The shell is also provided with a first dosing port connected to the first sub-reaction chamber, a second dosing port and a detection port that correspond one-to-one with and are connected to the second sub-reaction chamber, and a discharge port connected to the second reaction chamber. Along the direction of movement of the bleaching material, the detection port is arranged downstream of the corresponding second dosing port. The dosing device adds sodium hydroxide solution, non-silicone stabilizer, chelating agent and hydrogen peroxide solution to the first sub-reaction chamber through the first dosing port, and adds sodium hydroxide solution to the corresponding second sub-reaction chamber through each of the second dosing ports. The first detector is used to detect the pH value of the material to be bleached in the first detection area; The second detector is located at the detection port and is used to detect the pH value of the material to be bleached and the sodium hydroxide solution mixed in the second sub-reaction chamber. The third detector is used to detect the pH value of the material to be bleached in the second detection area; A driving device is used to drive the material to be bleached to move from the inlet end of the housing towards the outlet end of the housing.

2. The reaction apparatus for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulp according to claim 1, characterized in that, The second reaction chamber includes a third sub-reaction chamber and a fourth sub-reaction chamber that are sequentially connected in the direction of movement of the bleaching material. The third sub-reaction chamber is used for the bleaching material to react with the chemical agent for a target duration. The discharge port is connected to the fourth sub-reaction chamber. In the direction of movement of the bleaching material, the length of the fourth sub-reaction chamber is less than the length of the third reaction chamber.

3. The reaction apparatus for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulp according to claim 2, characterized in that, The number of the fourth sub-reaction chambers is multiple, and the multiple fourth sub-reaction chambers are arranged sequentially along the moving direction of the bleaching material. Each fourth sub-reaction chamber is provided with a discharge port. The reaction device also includes: The fourth detector is used to detect the pH value of the material to be bleached at the outlet. A sampling device is used to collect the material to be bleached at the outlet position in order to prepare a test sample; A whiteness detector is used to detect the whiteness of the test sample.

4. The reaction apparatus for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulp according to claim 1, characterized in that, The dosing device also includes: The first dosing tank is used to store non-silicone stabilizers. The first dosing tank is connected to the first dosing port through a first dosing pipe. A first dosing pump for pumping the non-silicone stabilizers is connected in series on the first dosing pipe. The second dosing tank is used to store the chelating agent. The second dosing tank is connected to the first dosing port through a second dosing pipe. A second dosing pump for pumping the chelating agent is connected in series on the second dosing pipe. The third dosing tank is used to store the sodium hydroxide solution. The third dosing tank is connected to the first dosing port and the second dosing port through a third dosing pipe. A third dosing pump for pumping the sodium hydroxide solution is connected in series on the third dosing pipe. The fourth dosing tank is used to store the hydrogen peroxide solution. The fourth dosing tank is connected to the first dosing port through a fourth dosing pipe. A fourth dosing pump for pumping the hydrogen peroxide solution is connected in series on the fourth dosing pipe.

5. The reaction apparatus for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulp according to claim 1, characterized in that, The housing includes: A first housing, the first housing extending along a first direction, and the first reaction chamber disposed within the first housing; The second housing extends along the first direction and is spaced apart from the first housing in the second direction. The second reaction chamber is disposed inside the second housing, and the first housing and the second housing are connected.

6. The reaction apparatus for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulp according to claim 5, characterized in that, The driving device includes: A first driving device is used to drive the material to be bleached inside the first housing to move along the first direction; The second driving device is used to drive the material to be bleached inside the second housing to move along the first direction.

7. The reaction apparatus for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulp according to claim 6, characterized in that, The first driving device includes: A first rotating shaft and a first bushing, the first rotating shaft extends along the first direction and is arranged inside the first housing, the axis of the first rotating shaft coincides with the axis of the first housing, the first bushing is sleeved on the outside of the first rotating shaft, and the first bushing is provided with a first blade extending spirally along the axis of the first rotating shaft on the outside. A first driving member, connected to one end of the first rotating shaft, is used to drive the first rotating shaft to rotate, thereby driving the material to be bleached to move along the first direction; and / or, the second driving device includes: The second rotating shaft and the second bushing extend along the second direction and are arranged inside the second housing. The axis of the second rotating shaft coincides with the axis of the second housing. The second bushing is sleeved on the outside of the second rotating shaft. The second bushing is provided with a second blade that extends spirally along the axis of the second rotating shaft. The second driving component is connected to one end of the second rotating shaft and is used to drive the second rotating shaft to rotate so as to drive the material to be bleached to move along the second direction.

8. The reaction apparatus for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulp according to claim 7, characterized in that, At least one steam inlet is formed on the sidewall of the first reaction chamber and the second reaction chamber. The reaction apparatus further includes: an air inlet pipe, one end of which is connected to the steam inlet, and the other end of which is adapted to be connected to an external steam source; and / or, A spoiler, said spoiler being disposed on at least a portion of the inner wall of the housing, and on at least a portion of the first blade and at least a portion of the second blade; and / or, A sealing element, which is disposed on the housing, is used to open or cover the discharge port.

9. A method for improving the bleaching efficiency of non-silica hydrogen peroxide stabilizers in chemimechanical pulp, used in the reaction apparatus for improving the bleaching efficiency of non-silica hydrogen peroxide stabilizers in chemimechanical pulp according to any one of claims 1-8, characterized in that, The method includes: Step S1: Add the material to be bleached into the first reaction chamber through the feed inlet; Step S2: The first portion of sodium hydroxide, accounting for 60% to 75% of the total amount of sodium hydroxide, non-silicon stabilizer, chelating agent and hydrogen peroxide solution are added into the first reaction chamber through the first dosing port to mix with the material to be bleached. At the same time, steam is introduced into the first reaction chamber to make the temperature reach the preset temperature. Step S3: Control the reaction time of the material to be bleached in the first sub-reaction chamber to reach a first preset duration; Step S4: Confirm whether the pH value of the first detection area meets the first preset value. If the pH value is lower than the first preset value, execute the first strategy. If the pH value is not lower than the first preset value, execute the second strategy. The first strategy includes: adding sodium hydroxide solution to the second sub-reaction chamber through the second dosing port to make the pH value reach a second preset value, the second preset value being greater than the first preset value; controlling the reaction time of the material to be bleached in the second sub-reaction chamber to reach a first preset duration; confirming whether the pH value of the second detection zone meets the first preset value; if the pH value is lower than the first preset value, repeating the first strategy until the total amount of sodium hydroxide has been added; if the pH value is not lower than the first preset value, executing the second strategy. The second strategy includes: controlling the reaction time of the material to be bleached in the second sub-reaction chamber to reach the first preset time, confirming whether the pH value of the second detection zone meets the first preset value, if the pH value is lower than the first preset value, repeating the first strategy until the total amount of sodium hydroxide is added, and if the pH value is not lower than the first preset value, executing the second strategy. Step S5: Control the reaction time of the material to be bleached in the third sub-reaction chamber to reach the target duration, and obtain the bleached material; Step S6: Detect the whiteness of the bleaching material and confirm whether the whiteness reaches the preset whiteness value. If the whiteness reaches the preset whiteness value, execute the third strategy; if the whiteness is lower than the preset whiteness value, execute the fourth strategy. The third strategy includes discharging the bleached material through a discharge port; The fourth strategy includes: confirming whether the pH of the bleaching material is higher than a third preset value; if so, after the bleaching material enters the fourth sub-reaction chamber and continues to react for a second preset time, confirming whether the whiteness at the outlet reaches a preset whiteness value; if the whiteness reaches the preset whiteness value, executing the third strategy; if the whiteness does not reach the preset whiteness value, executing the fourth strategy until the whiteness reaches the preset whiteness value; if not, discharging the bleaching material through the outlet and adding hydrogen peroxide solution to the first sub-reaction chamber through the first dosing port, and then repeating steps S3-S6 until the whiteness reaches the preset whiteness value.

10. The method for improving the bleaching efficiency of non-silicon hydrogen peroxide stabilizers in chemical mechanical pulp according to claim 9, characterized in that, The first preset value is 11.2-11.8, the second preset value is 12, the third preset value is 9, the whiteness value is 75%ISO-81%ISO, the first preset duration is 15min-20min, the target duration is 30min, and the second preset duration is 10min-20min.

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