A chemical pulping P-stage bleaching feeding system

Abstract

This utility model relates to a chemical pulping P-stage bleaching feeding system, comprising: a medium-consistency pump; a P-stage bleaching tower, wherein the medium-consistency pump is connected to the P-stage bleaching tower via a pipeline, and the medium-consistency pump is used to transport pulp into the P-stage bleaching tower; a P-tank, wherein the P-tank is connected to the P-stage bleaching tower via a pipeline; a post-bleaching tower, wherein the post-bleaching tower is connected to the washing machine via a pipeline; a first detection mechanism, wherein the first detection mechanism is disposed in the post-bleaching tower, and the first detection mechanism is used to detect the liquid level in the post-bleaching tower; and a control mechanism, wherein the first detection mechanism is electrically connected to the control mechanism, the medium-consistency pump is electrically connected to the control mechanism, and the control mechanism is used to receive and process the detection signal from the first detection mechanism and control the input frequency of the medium-consistency pump.

Description

Technical Field

[0001] This utility model relates to the field of papermaking pulping and bleaching technology, and in particular to a chemical pulping P-stage bleaching feeding system. Background Technology

[0002] In the bleaching section of a chemical pulping plant, the P-stage (hydrogen peroxide bleaching) is the core of mainstream elemental chlorine-free (ECF) or total chlorine-free (TCF) bleaching processes. Its core function is to use the oxidizing effect of hydrogen peroxide (H2O2) to remove residual lignin, pigments, and impurities from the pulp, improving pulp brightness and cleanliness while minimizing fiber damage. The feeding process, as the "front-end inlet" of the P-stage, directly determines the mixing efficiency of the pulp and bleaching chemicals, as well as the stability of initial reaction conditions, making it a crucial step in ensuring effective bleaching.

[0003] As the "front-end inlet" of the P-stage bleaching process, the core responsibility of the feeding process is to precisely deliver the pretreated pulp (usually medium-consistency pulp, 3%-5% concentration) to the P-stage bleaching tower, and simultaneously add chemicals such as hydrogen peroxide, stabilizers (e.g., sodium silicate), and pH adjusters (e.g., sodium hydroxide) to ultimately establish stable initial reaction conditions (pulp consistency deviation ±0.5%, pH deviation ±0.2, temperature deviation ±2℃). Existing feeding processes generally employ a "manual control room adjustment" mode, relying on operators to observe the status of downstream equipment (such as washer operating parameters and post-bleaching tower liquid level) through a central control room display screen, and then manually adjust parameters such as the frequency of the front-end medium-consistency pump and the opening of the chemical addition valve.

[0004] However, this model has significant technical defects when abnormal operating conditions occur in the backend: firstly, the response is delayed; secondly, the accuracy is insufficient; and thirdly, the coordination is poor, resulting in the problem of erroneous control. Summary of the Invention

[0005] Therefore, a chemical pulping P-stage bleaching feeding system is needed to address significant technical deficiencies in the bleaching section of existing chemical pulping workshops when abnormal conditions occur at the downstream end: firstly, response lag; secondly, insufficient precision; and thirdly, poor coordination. There are technical problems related to error control.

[0006] To achieve the above objectives, the inventors provide a chemical pulping P-stage bleaching feeding system, comprising:

[0007] Medium concentration pump;

[0008] The P-section bleaching tower is connected to the P-section bleaching tower via a pipeline, and the medium-concentration pump is used to transport the slurry into the P-section bleaching tower.

[0009] P-tank, which is connected to the P-section bleaching tower via a pipeline;

[0010] A pulp washing machine, wherein the pulp washing machine is connected to the P tank via a pipeline;

[0011] A bleaching tower, which is connected to the washing machine via a pipeline;

[0012] A first detection mechanism is installed inside the drift tower and is used to detect the liquid level inside the drift tower.

[0013] The system includes a control mechanism, the first detection mechanism being electrically connected to the control mechanism, and the intermediate concentration pump being electrically connected to the control mechanism. The control mechanism is used to receive and process the detection signal from the first detection mechanism and control the input frequency of the intermediate concentration pump.

[0014] As a preferred structure of this utility model, the chemical pulping P-stage bleaching feeding system further includes a second detection mechanism, which is disposed in the P tank and electrically connected to the control mechanism. The second detection mechanism is used to detect the liquid level in the P tank.

[0015] As a preferred structure of this utility model, the second detection mechanism is a second liquid level gauge, which is disposed in the upper middle part of the inner wall of the P tank.

[0016] In a preferred embodiment of this invention, the P-tank and the washing machine are located at the same horizontal level.

[0017] As a preferred structure of this utility model, the chemical pulping P-stage bleaching feeding system further includes a support base, which is fixedly installed. The P-channel is installed on the support base, and the bottom of the support base is at the same horizontal height as the bottom of the pulp washing machine.

[0018] As a preferred structure of this utility model, the first detection mechanism is a first liquid level gauge, which is located in the lower middle part of the inner wall of the drift tower.

[0019] As a preferred structure of this utility model, the chemical pulping P-stage bleaching feeding system further includes a flow detection mechanism, which is installed on the pipeline between the medium-consistency pump and the P-stage bleaching tower. The flow detection mechanism is electrically connected to the control mechanism and is used to detect the pulp delivery flow rate. The control mechanism is also used to receive and process the detection signal from the flow detection mechanism and control the input frequency of the medium-consistency pump.

[0020] As a preferred structure of this utility model, the chemical pulping P-stage bleaching feeding system further includes a concentration detection mechanism, which is installed inside the bleaching tower and electrically connected to the control mechanism. The concentration detection mechanism is used to detect the concentration of the pulp in the bleaching tower.

[0021] As a preferred structure of this utility model, the chemical pulping P-stage bleaching feeding system further includes a temperature detection mechanism, which is installed inside the bleaching tower and electrically connected to the control mechanism. The temperature detection mechanism is used to detect the temperature of the pulp inside the bleaching tower.

[0022] As a preferred structure of this utility model, the control mechanism includes a controller, a touch screen, and a plurality of control keys, all of which are electrically connected to the controller.

[0023] The advantages of the above technical solution, which differ from the existing technology, are as follows: The chemical pulping P-stage bleaching feeding system of this utility model detects the liquid level of the pulp in the bleaching tower in real time through the first detection mechanism. When the first detection mechanism detects that the liquid level of the pulp in the bleaching tower is lower than the preset value, the first detection mechanism sends a detection signal to the control mechanism. The control mechanism receives the detection signal, identifies and processes it, and controls to increase the input frequency of the medium-consistency pump, thereby increasing the pulp feed rate of the bleaching tower. Through the interlocking control between the first detection mechanism and the control mechanism, the efficiency and accuracy of system regulation are improved, the regulation time is shortened, the errors that may be caused by manual regulation are reduced, and the product quality is improved.

[0024] The above description of the invention is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the description and drawings, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is provided in conjunction with the specific embodiments and drawings of this application. Attached Figure Description

[0025] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of specific embodiments of this application and other related content, and should not be considered as limitations on this application.

[0026] In the accompanying drawings of the instruction manual:

[0027] Figure 1 This is a schematic diagram of the chemical pulping P-stage bleaching feeding system described in a specific embodiment;

[0028] Figure 2 The circuit diagram of the chemical pulping P-stage bleaching feeding system described in the specific implementation embodiment is shown below.

[0029] Figure 3 A circuit diagram of the control mechanism described in the specific implementation embodiment;

[0030] Figure 4 This is a front view of the drift tower as described in the specific embodiment;

[0031] Figure 5 This is a front view of the P-groove as described in the specific embodiment.

[0032] The reference numerals used in the above figures are explained as follows:

[0033] 1. Medium-concentration pump,

[0034] 2. P-section bleaching tower,

[0035] 3. P-groove

[0036] 4. Washing machine

[0037] 5. Float the back tower,

[0038] 6. The first testing agency,

[0039] 7. Second testing agency,

[0040] 8. Control mechanism,

[0041] 81. Controller

[0042] 82. Touchscreen

[0043] 83. Control keys,

[0044] 9. Support base,

[0045] 10. Flow detection agencies,

[0046] 11. Concentration testing institutions,

[0047] 12. Temperature detection agency. Detailed Implementation

[0048] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0049] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0050] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0051] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0052] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0053] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0054] As understood in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0055] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "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 specific embodiments or drawings. These expressions are only for the convenience of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. Furthermore, in this context, it should be understood that when it is mentioned that an element is connected "on" or "below" another element, it can be directly connected not only to the other element "on" or "below," but also indirectly connected to the other element "on" or "below" through an intermediate element.

[0056] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0057] Please see Figures 1 to 5 This embodiment relates to a chemical pulping P-stage bleaching feeding system, comprising:

[0058] Medium-consistency pump 1; Medium-consistency pump 1 specifically refers to a dedicated fluid conveying device used for conveying medium-consistency pulp with a concentration of 3%-15%. Medium-consistency pump 1 is connected to the inlet of the P-section bleaching tower 2 via a flanged pipeline, serving as the system's "front-end power source." Its motor is equipped with a frequency converter (preferably Schneider ATV320), which can change the speed by adjusting the input frequency (0-50Hz), thereby precisely controlling the pulp delivery rate (adjustment range is 30%-120% of the design flow rate). Simultaneously, a filter screen (5mm aperture) is installed at the inlet of medium-consistency pump 1 to filter large particulate impurities in the pulp (such as fiber bundles and bark fragments), preventing impeller jamming. In this embodiment, the frequency converter design replaces the traditional fixed-frequency pump, achieving continuously adjustable delivery rate.

[0059] The P-stage bleaching tower 2 is connected to the intermediate concentration pump 1 via pipeline. The intermediate concentration pump 1 is used to transport the slurry into the P-stage bleaching tower 2. The P-stage bleaching tower 2 is the core container for the hydrogen peroxide bleaching reaction. "P-stage" is an abbreviation for "Peroxide Bleaching Stage," and it is usually a vertical cylindrical structure (3-5m in diameter, 10-15m in height). The inner wall is made of 316L stainless steel (resistant to H2O2 and NaOH corrosion), which is different from the ordinary carbon steel tower body of other bleaching stages (such as D-stage and E-stage). Furthermore, the P-stage bleaching tower 2 is connected to the intermediate concentration pump 1 (inlet end, located at the bottom of the tower body) and the P-tank 3 (outlet end, located at the top of the tower body) via pipeline.

[0060] P-tank 3 is connected to the P-section bleaching tower 2 via pipelines. P-tank 3, short for "Peroxide Beaching Buffer Tank," is an intermediate buffer container located between the P-section bleaching tower 2 and the washing machine 4. It is typically a horizontal cylindrical structure (2-3m in diameter, 4-6m in length) with an epoxy resin anti-corrosion coating on its inner wall. Furthermore, P-tank 3 is connected via pipelines to the P-section bleaching tower 2 (feed end, located at the top of one end of the tank) and the washing machine 4 (discharge end). P-tank 3 serves to balance the flow of material from both ends, receiving continuous discharge from the P-section bleaching tower 2 and temporarily storing pulp to accommodate short shutdowns of the washing machine 4 (such as screen changing or cleaning), preventing the P-section bleaching tower 2 from stopping due to obstructed discharge.

[0061] A pulp washer 4 is connected to the P-tank 3 via a pipeline. The pulp washer 4 is a specialized device for removing residual chemicals (unreacted H2O2, lignin oxide fragments, sodium silicate, etc.) from bleached pulp. This system preferably uses a drum-type vacuum pulp washer 4. Furthermore, the pulp washer 4 is connected via a pipeline to the P-tank 3 (feed end, located on one side of the drum surface) and the bleaching tower 5 (discharge end, located on the other side of the drum surface).

[0062] The bleaching tower 5 is connected to the washer 4 via pipelines. The bleaching tower 5, short for "Bleached Pulp Storage Tank," is the final storage container at the back end of the system. It has a vertical cylindrical structure with an inner wall made of fiberglass. Furthermore, the bleaching tower 5 is connected via pipelines to the washer 4 (feed end, located at the bottom of the tower) and the subsequent papermaking section (discharge end, located at the bottom of the tower). The bleaching tower 5 provides storage, allowing continuous production in the papermaking section (avoiding paper breaks caused by short stops of the washer 4).

[0063] A first detection mechanism 6 is installed inside the bleaching tower 5 and is used to detect the liquid level inside the bleaching tower 5. The first detection mechanism 6 is a dedicated device installed inside the bleaching tower 5 for real-time detection of the pulp level; it is either a radio frequency admittance level gauge or an ultrasonic level gauge. The first detection mechanism 6 is used to detect the pulp level inside the bleaching tower 5 in real time.

[0064] The system includes a control mechanism 8, with the first detection mechanism 6 electrically connected to the control mechanism 8, and the intermediate concentration pump 1 also electrically connected to the control mechanism 8. The control mechanism 8 receives and processes the detection signals from the first detection mechanism 6 and controls the input frequency of the intermediate concentration pump 1. The control mechanism 8 is the "core control unit" of the system, consisting of a controller 81 (PLC programmable logic controller 81) and human-machine interface components (touchscreen 82 + control keys 83). The control mechanism 8 is installed in the workshop control room and is connected to each detection mechanism (signal input) and the intermediate concentration pump 1 (command output) via wires.

[0065] Specifically, in the chemical pulping P-stage bleaching feeding system of this embodiment, the first detection mechanism 6 monitors the liquid level of the slurry in the bleaching tower 5 in real time. When the first detection mechanism 6 detects that the liquid level of the slurry in the bleaching tower 5 is lower than a preset value, the first detection mechanism 6 sends a detection signal to the control mechanism 8. The control mechanism 8 receives the detection signal, processes it, and controls the input frequency of the intermediate concentration pump 1 to increase the slurry feed rate of the bleaching tower 5. Through the interlocking control of the first detection mechanism 6 and the control mechanism 8, the efficiency and accuracy of system regulation are improved, the regulation time is shortened, errors that may be caused by manual regulation are reduced, and product quality is improved. It should be noted that the preset value in this embodiment can be set according to the actual tower height of the bleaching tower 5.

[0066] Optionally, in some embodiments, such as Figures 1 to 5 As shown, the chemical pulping P-stage bleaching feeding system also includes a second detection mechanism 7, which is disposed within the P tank 3 and electrically connected to the control mechanism 8. The second detection mechanism 7 is used to detect the liquid level within the P tank 3. Specifically, the second detection mechanism 7 is a detection device installed within the P tank 3 for detecting the slurry level; it is either a radio frequency admittance level gauge or an ultrasonic level gauge. The second detection mechanism 7 monitors the slurry level within the P tank 3 in real time.

[0067] Optionally, in some embodiments, such as Figures 1 to 5 As shown, the second detection mechanism 7 is a second level gauge, which is located in the upper middle part of the inner wall of the P tank 3. Specifically, the second level gauge is vertically installed in the upper middle part of the inner wall of the P tank 3 (the installation height is 2 / 3 of the total height of the tank) and is electrically connected to the control mechanism 8 through a wire.

[0068] Specifically, in this embodiment, such as Figures 1 to 5 As shown, the first detection mechanism 6 monitors the slurry level in the bleaching tower 5 in real time. When the first detection mechanism 6 detects that the slurry level in the bleaching tower 5 is lower than a preset value, it sends a detection signal to the control mechanism 8. The control mechanism 8 receives the detection signal, processes it, and controls to increase the input frequency of the intermediate concentration pump 1, thereby increasing the slurry feed rate of the bleaching tower 5. At the same time, the second detection mechanism 7 also monitors the slurry level in the P tank 3 in real time. When the second detection mechanism 7 detects that the slurry level in the P tank 3 is higher than a set value, it sends a detection signal to the control mechanism 8. The control mechanism 8 receives the detection signal, processes it, and controls to decrease the input frequency of the intermediate concentration pump 1, reducing the slurry input rate. The feed rate is adjusted in real time based on the on-site production data. Through the interlocking control of the first detection mechanism 6, the second detection mechanism 7, and the control mechanism 8, the efficiency and accuracy of system regulation are improved, the regulation time is shortened, errors that may be caused by manual regulation are reduced, and product quality is improved. It should be noted that the preset value in this embodiment can be set according to the actual tower height of the bleaching tower 5.

[0069] It should be noted that the preset values ​​in this embodiment can be set according to the actual height of the drift tower 5. It should also be noted that the preset values ​​in this embodiment can be set according to the actual height of the P-slot 3.

[0070] Optionally, in some embodiments, such as Figures 1 to 5 As shown, the P-tank 3 and the pulp washer 4 are located at the same horizontal height. In this embodiment, the central axis of the discharge port of the P-tank 3 and the central axis of the inlet of the pulp washer 4 are on the same horizontal plane, which is different from the traditional design of "P-tank 3 is higher than the pulp washer 4 (height difference 1-2m)" or "P-tank 3 is lower than the pulp washer 4 (requiring an additional conveying pump)". The core is to use gravity to achieve the gravity flow of pulp.

[0071] Furthermore, the discharge end of P-tank 3 is directly connected to the feed end of the pulp washer 4 via a short pipe. A manual butterfly valve is installed in the pipeline (for easy shut-off when the pulp washer 4 stops). The core function is "unpowered conveying": utilizing the slope of the inclined bottom plate of P-tank 3 and gravity, the pulp flows naturally into the pulp washer 4, eliminating the need for an additional conveying pump, thus saving power consumption and reducing costs. Gravity flow avoids the shearing action of the conveying pump (the shearing force of traditional pulp pumps reduces fiber breaking length by 3%-5%), improving pulp strength by 4%; it also reduces pump maintenance (such as bearing replacement and seal repair), lowering annual maintenance costs.

[0072] Optionally, in some embodiments, such as Figures 1 to 5As shown, the chemical pulping P-stage bleaching feeding system also includes a support base 9, which is fixedly installed. The P-channel 3 is mounted on the support base 9, and the bottom of the support base 9 is at the same horizontal height as the bottom of the washing machine 4. The support base 9 is a dedicated support structure for fixing the P-channel 3, welded from Q235 carbon steel, and has sufficient load-bearing capacity. The support base 9 is a skirt-like structure.

[0073] Optionally, in some embodiments, such as Figures 1 to 5 As shown, the first detection mechanism 6 is a first level gauge, which is located in the lower middle part of the inner wall of the drift tower 5. Specifically, the first level gauge is vertically installed in the lower middle part of the inner wall of the drift tower 5 (the installation height is 1 / 3 to 1 / 2 of the total height of the tower), and is electrically connected to the control mechanism 8 through a shielded wire.

[0074] Optionally, in some embodiments, such as Figures 1 to 5 As shown, the chemical pulping P-stage bleaching feeding system also includes a flow detection mechanism 10. The flow detection mechanism 10 is installed on the pipeline between the intermediate-consistency pump 1 and the P-stage bleaching tower 2. The flow detection mechanism 10 is electrically connected to the control mechanism 8. The flow detection mechanism 10 is used to detect the pulp delivery flow rate. The control mechanism 8 is also used to receive and process the detection signal from the flow detection mechanism 10 and control the input frequency of the intermediate-consistency pump 1. The flow detection mechanism 10 is an electromagnetic flowmeter. The flow detection mechanism 10 detects the pulp flow rate in real time and sends the detection signal to the control mechanism 8. The control mechanism 8 performs coupled calculations based on the detection value of the flow detection mechanism 10 and the liquid level value of the first detection mechanism 6 to dynamically correct the output frequency of the intermediate-consistency pump 1, reducing the risk of equipment damage.

[0075] Optionally, in some embodiments, such as Figures 1 to 5 As shown, the chemical pulping P-stage bleaching feeding system also includes a concentration detection mechanism 11, which is installed inside the bleaching tower 5 and electrically connected to the control mechanism 8. The concentration detection mechanism 11 is used to detect the concentration of the pulp inside the bleaching tower 5. The concentration detection mechanism 11 is an optical refractometer. The concentration detection mechanism 11 is installed in the middle of the bleaching tower 5 (immersed in the pulp) and electrically connected to the control mechanism 8 via wires. Its core function is "terminal concentration feedback": real-time detection of the pulp concentration inside the bleaching tower 5.

[0076] Optionally, in some embodiments, such as Figures 1 to 5As shown, the chemical pulping P-stage bleaching feeding system also includes a temperature detection mechanism 12, which is installed inside the bleaching tower 5 and electrically connected to the control mechanism 8. The temperature detection mechanism 12 is used to detect the temperature of the pulp inside the bleaching tower 5. The temperature detection mechanism 12 is a platinum resistance thermometer installed inside the bleaching tower 5 to detect the pulp temperature. The temperature detection mechanism 12 is mounted on the wall of the bleaching tower 5 via a flange (the probe is immersed in the pulp) and electrically connected to the control mechanism 8 via a wire. The existing bleaching tower 5 only monitors the liquid level and cannot determine whether the abnormal liquid level is caused by excessively high pulp concentration (slow flow) or excessively low temperature (high viscosity). With the addition of the concentration detection mechanism 11 and the temperature detection mechanism 12, the control mechanism 8 can distinguish the cause of the abnormality (e.g., high liquid level, high concentration → need to increase the dewatering efficiency of the pulp washer 4, rather than simply reducing the feed rate), avoiding blind adjustments and improving process accuracy.

[0077] Optionally, in some embodiments, such as Figures 1 to 5 As shown, the control mechanism 8 includes a controller 81, a touch screen 82, and multiple control keys 83, all of which are electrically connected to the controller 81. The controller 81 has a built-in adjustment algorithm that calculates the adjustment amount based on detection signals (e.g., calculating the frequency reduction value of the intermediate concentration pump 1 when the liquid level is higher than the upper limit). The touch screen 82 displays system parameters in real time (frequency of intermediate concentration pump 1, liquid level of drift tower 5 and P tank 3, slurry flow rate, concentration, temperature, etc.) and supports parameter settings (e.g., liquid level threshold, slurry concentration target value, etc.). The control keys 83 (emergency pump stop key, manual / automatic switch key, parameter reset key) are used for emergency operation. Its core function is "signal processing - command output - human-machine interaction": receiving signals from various detection mechanisms, performing algorithm calculations, and sending frequency adjustment commands to the intermediate concentration pump 1, while also supporting manual intervention.

[0078] Specifically, in the chemical pulping P-stage bleaching feeding system of this embodiment, under normal operating conditions, the medium-consistency pump 1 operates at a frequency of 40Hz (with a delivery capacity of 40m³ / h). 3 / h) 3.5% concentration pulp is transported to the P-section bleaching tower 2, mixed with H2O2 (addition amount 1.2% oven-dry pulp), and reacted at 75℃ for 90min; after bleaching, the pulp flows into the P tank 3 (liquid level maintained at 1 / 2-2 / 3 tank height), flows by gravity to the pulp washer 4, and after purification (residual H2O2 ≤ 0.1%), flows into the bleaching tower 5 (liquid level maintained at 1 / 3-2 / 3 tower height), and is finally transported to the papermaking section.

[0079] When an abnormal condition occurs at the back end (the filter of the washer 4 becomes clogged), the clogged filter causes a decrease in pulp flow, and the liquid level in the bleaching tower 5 drops from 2 / 3 of the tower height to 1 / 4 of the tower height (below the lower limit). The first detection mechanism 6 transmits a signal to the control mechanism 8 within 5 seconds. The control mechanism 8 compares the signal with that of the second detection mechanism 7 (the liquid level in tank P 3 rises from 1 / 2 of the tank height to 2 / 3 of the tank height, confirming that the abnormality originates from the washer 4). The control mechanism 8 calculates through an algorithm that the frequency of the medium-consistency pump 1 needs to be increased from 40Hz to 45Hz (increasing the delivery volume to 45m³). 3 / h); the control mechanism 8 sends a frequency adjustment command to the intermediate concentration pump 1, and the adjustment is completed within 10 seconds. The liquid level in the drift column 5 gradually rises back to the normal range; at the same time, the flow detection mechanism 10 reports the actual delivery volume of 45m³. 3 / h, the concentration detection mechanism 11 monitors and maintains the post-bleaching pulp concentration at 3.5% ± 0.2%, and the control is completed. Through the interlocking control of the first detection mechanism 6, the second detection mechanism 7, the flow detection mechanism 10, the concentration detection mechanism 11, and the control mechanism 8, the efficiency and accuracy of system control are improved, the control time is shortened, the errors that may be caused by manual control are reduced, and the product quality is improved.

[0080] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A chemical pulping P-stage bleaching feeding system, characterized in that, include: Medium concentration pump; The P-section bleaching tower is connected to the P-section bleaching tower via a pipeline, and the medium-concentration pump is used to transport the slurry into the P-section bleaching tower. P-tank, which is connected to the P-section bleaching tower via a pipeline; A pulp washing machine, wherein the pulp washing machine is connected to the P tank via a pipeline; A bleaching tower, which is connected to the washing machine via a pipeline; A first detection mechanism is installed inside the drift tower and is used to detect the liquid level inside the drift tower. The system includes a control mechanism, the first detection mechanism is electrically connected to the control mechanism, the intermediate concentration pump is electrically connected to the control mechanism, and the control mechanism is used to receive and process the detection signal from the first detection mechanism and control the input frequency of the intermediate concentration pump.

2. The chemical pulping P-stage bleaching feeding system according to claim 1, characterized in that: The chemical pulping P-stage bleaching feeding system also includes a second detection mechanism, which is located inside the P tank and is electrically connected to the control mechanism. The second detection mechanism is used to detect the liquid level inside the P tank.

3. The chemical pulping P-stage bleaching feeding system according to claim 2, characterized in that: The second detection mechanism is a second liquid level gauge, which is located in the upper middle part of the inner wall of the P tank.

4. The chemical pulping P-stage bleaching feeding system according to claim 1, characterized in that: The P tank and the washing machine are located at the same horizontal level.

5. The chemical pulping P-stage bleaching feeding system according to claim 1 or 4, characterized in that: The chemical pulping P-stage bleaching feeding system also includes a support base, which is fixedly installed. The P-tank is installed on the support base, and the bottom of the support base is at the same horizontal height as the bottom of the pulp washing machine.

6. The chemical pulping P-stage bleaching feeding system according to claim 1, characterized in that: The first detection mechanism is a first level gauge, which is located in the lower middle part of the inner wall of the drift tower.

7. The chemical pulping P-stage bleaching feeding system according to claim 1, characterized in that: The chemical pulping P-stage bleaching feeding system also includes a flow detection mechanism, which is installed on the pipeline between the medium-consistency pump and the P-stage bleaching tower. The flow detection mechanism is electrically connected to the control mechanism and is used to detect the pulp delivery flow rate. The control mechanism is also used to receive and process the detection signal from the flow detection mechanism and control the input frequency of the medium-consistency pump.

8. The chemical pulping P-stage bleaching feeding system according to claim 1, characterized in that: The chemical pulping P-stage bleaching feeding system also includes a concentration detection mechanism, which is installed inside the bleaching tower and electrically connected to the control mechanism. The concentration detection mechanism is used to detect the concentration of the pulp in the bleaching tower.

9. The chemical pulping P-stage bleaching feeding system according to claim 1 or 8, characterized in that: The chemical pulping P-stage bleaching feeding system also includes a temperature detection mechanism, which is installed inside the bleaching tower and is electrically connected to the control mechanism. The temperature detection mechanism is used to detect the temperature of the pulp inside the bleaching tower.

10. The chemical pulping P-stage bleaching feeding system according to claim 1, characterized in that: The control mechanism includes a controller, a touch screen, and multiple control keys, all of which are electrically connected to the controller.

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