A method and system for phosphoric acid delivery for phosphate fertilizer production

Abstract

The application relates to the technical field of phosphate fertilizer production, and discloses a phosphoric acid conveying method and system for phosphate fertilizer production. The method regularly acquires a liquid level image of phosphoric acid in a storage tank; a crystallization area in the liquid level image is recognized based on target detection, and a crystallization feature of the liquid level image is extracted according to the distribution of the crystallization area in the image; the crystallization feature of the liquid level image is input into a prediction model for representing the mapping relationship between the crystallization feature in the phosphoric acid liquid level image and the crystallization proportion in the phosphoric acid liquid, so that the phosphoric acid crystallization proportion in the current storage tank is output; the phosphoric acid crystallization proportion R C is analyzed to determine the size of a preset proportion threshold R TH ; if R C >= R TH , a heating assembly is controlled to continuously heat the phosphoric acid in the storage tank, and the liquid level monitoring is continuously performed; if R C <R TH , a feedable stage of a preset time limit is executed. When being in the feedable stage and receiving a feeding instruction, a conveying assembly is controlled to output the phosphoric acid in the storage tank to a designated phosphate fertilizer production line.

Description

Technical Field

[0001] This invention relates to the field of phosphate fertilizer production technology, specifically a method and system for delivering phosphoric acid in phosphate fertilizer production. Background Technology

[0002] Phosphoric acid is the main raw material for phosphate fertilizer production. By controlling the reaction conditions, phosphoric acid is made into soluble phosphate. After acidification and alkalinity adjustment, the generated phosphate forms solid particles through precipitation reaction. Then, the final phosphate fertilizer product is obtained through processes such as centrifugation, drying and pulverization.

[0003] Currently, in the phosphate fertilizer production process, the commonly used orthophosphoric acid solution needs to be stored in advance, and then pumped into the reactor and other equipment through pipelines when needed. Orthophosphoric acid solution is prone to crystallization at low temperatures (<21℃). Although this does not affect subsequent chemical reactions, it can easily clog the delivery pipelines, leading to instability in the exchange between phosphoric acid and the external environment, and thus affecting the smooth progress of phosphate fertilizer production. Therefore, this problem urgently needs to be solved. Summary of the Invention

[0004] To address the technical problem in existing technologies where low-temperature phosphoric acid in storage tanks easily crystallizes, leading to unstable transportation and thus affecting the smooth progress of phosphate fertilizer production, this invention provides a phosphoric acid transportation method and system for phosphate fertilizer production.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention discloses a method for delivering phosphoric acid in phosphate fertilizer production, comprising the following steps, namely S1 to S4.

[0007] S1. Periodically obtain images of the phosphoric acid level inside the storage tank.

[0008] S2. Based on target detection, identify the crystallized regions in the liquid surface image, and extract the crystallization features of the liquid surface image according to the distribution of the crystallized regions in the image.

[0009] S3. Input the crystallization features of the liquid surface image into a prediction model that characterizes the mapping relationship between the crystallization features in the phosphoric acid liquid surface image and the proportion of crystals in the phosphoric acid, thereby outputting the current proportion of phosphoric acid crystals R in the storage tank. C .

[0010] S4. Analysis of the proportion of phosphoric acid crystals R C Compared with the preset percentage threshold R TH Based on the size, make the following decision:

[0011] If R C ≥R TH Then, a heating element is controlled to continuously heat the phosphoric acid in the storage tank, and the process returns to step S1 to continuously monitor the liquid level until the real-time crystallization ratio in the storage tank is not higher than the ratio threshold R.TH then stop heating.

[0012] If R C < R TH , then execute a feeding-available phase with a preset time limit. When in the feeding-available phase and a feeding instruction is received, control a conveying assembly to output phosphoric acid in the storage tank to a designated phosphate fertilizer production line.

[0013] As a further improvement to the above solution, the crystallization characteristics include total crystallization area, number of crystals, and average crystal size. The prediction model is obtained by training using a linear regression model.

[0014] As a further improvement to the above solution, before step S1, the real-time liquid level of phosphoric acid in the current storage tank is also obtained. When the real-time liquid level is lower than a rated liquid level value, the conveying assembly is controlled to continuously replenish phosphoric acid into the storage tank until the real-time liquid level exceeds the rated liquid level value.

[0015] As a further improvement to the above solution, in step S2, the liquid surface area in the liquid surface image is equally divided into n sector-shaped sub-regions around the center of the storage tank, where n≥2. n discharge holes are arranged on the storage tank, which correspond to the n sub-regions one by one. The projection of each discharge hole along the vertical direction falls within the coverage of the corresponding sub-region. The pixel proportion of crystallization area p in each sub-region i , wherein 1≤i≤n, is the number of pixels in the crystallization area in sub-region i, is the number of pixels of sub-region i.

[0016] In step S4, if R C ≥ R TH , then arranging the pixel proportions of the crystallization areas of the n sub-regions into a queue in ascending order, and controlling the conveying assembly to output phosphoric acid to be heated out of the storage tank through at least one discharge hole near the front end of the queue.

[0017] The invention also discloses a phosphoric acid conveying system for phosphate fertilizer production, comprising a conveying assembly matched with a storage tank, a heating assembly, and an image acquisition module. The image acquisition module is fixedly installed on the top cover of the storage tank, and is configured to acquire a liquid surface image of phosphoric acid inside the storage tank and send the image to a controller. The controller is configured to control the conveying assembly and the heating assembly, so as to realize regular removal of phosphoric acid crystallization in the storage tank, and supplementation and output of phosphoric acid in the storage tank. The controller applies the above phosphoric acid conveying method for phosphate fertilizer production.

[0018] As a further improvement to the above scheme, the conveying assembly includes infusion pipe one, infusion pipe two, infusion pipe three, a conveying pump, and infusion pipe four. One end of infusion pipe one is connected to the discharge port at the bottom of the storage tank, and the other end of infusion pipe one is connected in series with infusion pipe two, the heating assembly, infusion pipe three, the conveying pump, and infusion pipe four. The end of infusion pipe four is connected to the inlet port at the top of the storage tank, thereby forming a circulation loop outside the storage tank for heating phosphoric acid by the heating assembly.

[0019] As a further improvement to the above scheme, multiple discharge holes are circumferentially opened at the bottom of the tank sidewall. Multiple delivery pipes are provided, each corresponding to one of the multiple discharge holes. The same end of each delivery pipe is connected to its corresponding discharge hole, and the other end of each delivery pipe is connected to multiple inlets of a multi-way connector. The single outlet of the multi-way connector is connected to one end of a second delivery pipe. Each inlet of the multi-way connector is equipped with a one-way valve to prevent phosphoric acid backflow. Each delivery pipe is equipped with a solenoid valve.

[0020] As a further improvement to the above scheme, a solenoid valve three is installed on the feed pipe three. A feed pipe for replenishing phosphoric acid into the storage tank is connected to the feed pipe between the solenoid valve three and the inlet of the delivery pump via a tee joint. A feed solenoid valve is installed on the feed pipe. A solenoid valve four is installed on the feed pipe four. A feed supply pipe for discharging phosphoric acid to a designated phosphate fertilizer production line is connected to the feed pipe between the solenoid valve four and the outlet of the delivery pump via a tee joint. A feed supply solenoid valve is installed on the feed pipe.

[0021] As a further improvement to the above solution, the controller is also used for:

[0022] When it is necessary to remove phosphoric acid crystals from the storage tank, simultaneously control solenoid valve 1, solenoid valve 3, solenoid valve 4 and the delivery pump to open, control the feeding solenoid valve and the supply solenoid valve to close, and control the heating components to turn on for heating.

[0023] When phosphoric acid needs to be output from the storage tank, the solenoid valves 1, 3, the feeding solenoid valve and the delivery pump are opened simultaneously, the feeding solenoid valve and the solenoid valve 4 are closed, and the heating components are turned off.

[0024] When phosphoric acid needs to be added to the storage tank, the feeding solenoid valve, solenoid valve four and the delivery pump are opened simultaneously, while solenoid valve one, solenoid valve three and the feeding solenoid valve are closed, and the heating components are turned off.

[0025] As a further improvement to the above scheme, the heating assembly includes a heat exchange shell and heat exchange tubes. The heat exchange shell has a shell-side inlet and a shell-side outlet that communicate with the interior of the heat exchange shell. The heat exchange tubes are installed inside the heat exchange shell, with the tube-side inlet connected to the second infusion tube and the tube-side outlet connected to the third infusion tube.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. The phosphoric acid conveying method for phosphate fertilizer production disclosed in this invention obtains the crystallization characteristics of phosphoric acid inside the storage tank through target detection technology, thereby monitoring the crystallization ratio of phosphoric acid, and circulating and heating the liquid in the storage tank when the warning conditions are met, so as to ensure that the conveying component can transmit phosphoric acid liquid more smoothly in the subsequent feeding stage and ensure the smooth progress of phosphate fertilizer production.

[0028] 2. This invention trains a linear regression model to obtain a prediction model that can comprehensively consider the multi-dimensional crystallization features in the image crystallization area, thereby reflecting the proportion of crystallization in phosphoric acid in the storage tank and improving the accuracy of monitoring results.

[0029] 3. This invention acquires the phosphoric acid level in the storage tank in real time before detecting phosphoric acid crystallization, and controls the delivery component to continuously replenish the phosphoric acid in the tank when the phosphoric acid is insufficient. On the one hand, it ensures that each liquid level image collected corresponds to a standard liquid level value, and monitors the phosphoric acid crystallization under the same conditions (scenario); on the other hand, it ensures that there is sufficient phosphoric acid in the storage tank to carry out the subsequent supply stage.

[0030] 4. Based on the above-mentioned target detection technology, the liquid surface area in the liquid surface image is divided into multiple fan-shaped sub-regions around the center of the storage tank. These sub-regions correspond one-to-one with multiple discharge holes opened on the storage tank. According to the pixel ratio of the crystallized area in each sub-region, the conveying component is controlled to output the phosphoric acid to be heated from at least one discharge hole near the front end of the queue to the outside of the storage tank. The area with less or no crystallization in the storage tank is given priority for the in-tank-out-tank circulation heating of phosphoric acid, thereby avoiding or reducing the occurrence of crystallization clogging the discharge hole in areas with more phosphoric acid crystals.

[0031] 5. The conveying system of the present invention, through optimizing the structural layout of the conveying pipeline, conveying pump, and solenoid valve group, not only realizes the basic function of heating phosphoric acid, but also, with only one conveying pump, can separately replenish phosphoric acid solution into the storage tank and output the phosphoric acid solution from the storage tank to designated equipment or production lines such as reaction vessels. By applying the above conveying method, it accommodates at least three working modes (heating mode, replenishing mode, and feeding mode), possessing multi-functionality and multi-condition practicality. Furthermore, the system is easy to integrate and assemble with other equipment or production lines in phosphate fertilizer production. Attached Figure Description

[0032] Figure 1 This is a flowchart of a phosphoric acid delivery method for phosphate fertilizer production in an embodiment of the present invention.

[0033] Figure 2This is a front view of a phosphoric acid delivery system for phosphate fertilizer production in an embodiment of the present invention.

[0034] Figure 3 This is a three-dimensional structural schematic diagram of a phosphoric acid delivery method for phosphate fertilizer production in an embodiment of the present invention.

[0035] Figure 4 for Figure 2 A schematic diagram of the internal structure of the medium-sized storage tank.

[0036] Figure 5 This is a schematic diagram showing the relative positions of the liquid surface area, multiple fan-shaped sub-areas, and multiple infusion pipes installed at the discharge holes in the liquid surface image acquired by the image acquisition module in this embodiment of the invention; the transparent columnar shape in the figure can be understood as phosphoric acid in the storage tank.

[0037] Figure 6 for Figure 2 A top-view cross-sectional view of the central storage tank at its six discharge ports.

[0038] Figure 7 This is a three-dimensional layout diagram of the six infusion tubes in an embodiment of the present invention.

[0039] Figure 8 This is a partial front view schematic diagram of the conveying component and the heating component in an embodiment of the present invention.

[0040] Figure 9 for Figure 8 Liquid flow diagrams for the conveying and heating components in three operating modes.

[0041] Figure 10 This is a schematic diagram of the internal structure of the heating component in an embodiment of the present invention.

[0042] In the diagram: 1. Storage tank; 11. Discharge port; 12. Inlet port; 13. Top cover; 2. Conveying assembly; 21. Infusion pipe one; 22. Infusion pipe two; 23. Infusion pipe three; 24. Infusion pipe four; 25. Conveying pump; 3. Heating assembly; 31. Heat exchange shell; 311. Shell-side inlet; 312. Shell-side outlet; 32. Heat exchange tube; 321. Tube-side inlet; 322. Tube-side outlet; 4. Image acquisition module; 51. Solenoid valve one; 52. Check valve; 53. Solenoid valve three; 54. Solenoid valve four; 55. Feeding solenoid valve; 56. Feeding solenoid valve; 6. Multi-way connector; 7. T-connector; 8. Feeding pipe; 9. Feeding pipe. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Please see Figures 1 to 4 This invention provides a phosphoric acid transport method for phosphate fertilizer production. The method can be implemented through a phosphoric acid transport system, which mainly includes a storage tank 1, a transport component 2, a heating component 3, an image acquisition module 4, and a controller (not shown). The system will be described in detail below.

[0045] The phosphoric acid delivery method for phosphate fertilizer production in this embodiment may include the following steps, namely S1 to S4.

[0046] S1. Periodically obtain images of the phosphoric acid level inside storage tank 1.

[0047] In some embodiments, a high-definition camera can be installed inside or outside the storage tank 1 to capture images of the phosphoric acid liquid surface. The camera periodically (e.g., every 12 hours or 24 hours) takes photos of the liquid inside the storage tank 1 and transmits these photos to a controller, computer, or cloud server for further processing. It should be noted that conditions such as supplemental lighting and static placement can be set when acquiring liquid surface images to maintain uniform light intensity during image acquisition, thereby reducing noise caused by factors such as shadows, low light, and liquid disturbance. Additionally, the acquired liquid surface images can be pre-processed and enhanced, with background subtraction or segmentation to meet the needs of subsequent target detection. It should be understood that since the inner wall cross-sectional profile of a commonly used storage tank 1 is circular, the liquid surface area in the liquid surface image acquired by the image acquisition module 4 located at the center of the top cover 13 of the storage tank 1 can be approximately or converted into a circle for subsequent further segmentation of the liquid surface area. A removable transparent protective cover (not shown) can also be installed at the bottom of the top cover 13 to protect the image acquisition module 4 from phosphoric acid corrosion.

[0048] In some embodiments, before executing step S1, the real-time liquid level of phosphoric acid in storage tank 1 can be obtained using technologies such as a level gauge or image recognition. When the real-time liquid level is lower than a rated liquid level value, the control delivery component 2 continuously replenishes phosphoric acid into storage tank 1 until the real-time liquid level exceeds (reaches) the rated liquid level value. This ensures, on the one hand, that each collected liquid level image corresponds to a standard liquid level value, allowing for monitoring of phosphoric acid crystallization under the same conditions (scenario); and on the other hand, it ensures that storage tank 1 contains sufficient phosphoric acid solution to perform the subsequent supply stage.

[0049] S2. Based on target detection, identify the crystallized regions in the liquid surface image, and extract the crystallization features of the liquid surface image according to the distribution of the crystallized regions in the image.

[0050] Since solid phosphoric acid crystals typically become more turbid or exhibit subtle color changes when solid crystals form in the liquid, and the surface may appear granular or uneven, solid phosphoric acid crystals differ from liquid phosphoric acid in color, texture, and shape. Therefore, traditional object detection algorithms can be used to extract features from crystalline regions in images (such as edge detection, morphological operations, and thresholding).

[0051] In this embodiment, an existing target detection model such as the YOLO model can be used to collect a large number of samples to form a sample set for training and validating the target detection model. The sample set can consist of liquid surface images of phosphoric acid liquid inside storage tank 1 at different degrees of crystallization when it is at the rated liquid level. By adjusting the temperature at the rated liquid level to induce different degrees of crystallization on the liquid surface and / or inside the liquid, liquid surface images are collected and the crystallized areas in the images are manually labeled, thereby forming a large number of samples to form the sample set. By dividing the sample set into a training set, a validation set, and a test set according to a preset ratio, the target detection model is trained, validated, and tested sequentially, thereby using a qualified crystallization region target detection model to identify the crystallized areas in the real-time liquid surface images.

[0052] Additionally, please see Figure 5 In step S2, the liquid surface area in the liquid surface image is further divided into n sector-shaped sub-regions around the center of tank 1, where n ≥ 2. Tank 1 has n discharge holes 11, each corresponding to one of the n sub-regions. The projection of each discharge hole 11 along the vertical direction falls within the coverage area of ​​its corresponding sub-region. The pixel percentage of the crystallized region in each sub-region is p. i , Where 1≤i≤n, denoted as the number of pixels in the crystalline region within sub-region i. Let n be the number of pixels in sub-region i. In this embodiment, n = 6, that is, there are a total of six discharge holes 11, that is, the liquid surface area in the liquid surface image is divided into six fan-shaped sub-regions around the center of the storage tank 1; the infusion pipe 21 installed at each discharge hole 11 extends into the coverage area of ​​the corresponding sub-region, so as to preferentially output the phosphoric acid solution in that area.

[0053] S3. Input the crystallization features of the liquid surface image into a prediction model that characterizes the mapping relationship between the crystallization features in the phosphoric acid liquid surface image and the proportion of crystals in phosphoric acid, thereby outputting the current proportion of phosphoric acid crystals R in storage tank 1. C .

[0054] It should be noted that the above prediction model estimates the actual crystallization ratio based on the crystallization characteristics in the liquid surface image. The crystallization ratio reflects the current cleanliness of phosphoric acid in storage tank 1. The specific estimation process is as follows:

[0055] (1) Quantify the crystallization features into specific numerical values; in this embodiment, the crystallization features may include the total crystal area, the number of crystals, and the average crystal size. In other embodiments, the crystallization features may also include the crystal shape, distribution, etc. For example, the total crystal area can be quantized by converting the pixel ratio of the crystal area.

[0056] (2) The quantified crystallization features are input into the prediction model, and the actual crystallization ratio in the liquid is calculated. The prediction model can be calibrated and verified using experimental data. Similar to the target detection described above, liquid surface image data is collected, and the actual crystallization ratio of the corresponding liquid samples is recorded. The collected dataset is then used to train the prediction model, and the model parameters are adjusted to optimize performance. In this embodiment, the prediction model is trained using a linear regression model. In other embodiments, machine learning models (such as decision trees, support vector machines, etc.) can also be used. Phosphate crystallization ratio R C The formula for expressing it is:

[0057] R C =β0+β1×δ1+β2×δ2+β3×δ3

[0058] In the formula, β0, β1, β2, and β3 are the coefficients of the linear regression model, estimated using training data. δ1, δ2, and δ3 represent the total area of ​​crystallization, the number of crystals, and the average crystal size in the real-time liquid surface image, respectively.

[0059] After a certain training process has been completed on the prediction model, the performance of the prediction model can be verified using an independent test set, and relevant indicators can be calculated to evaluate the quality of the model, thereby deciding whether to continue training or optimize the model structure or adjust the parameters.

[0060] S4. Analysis of the proportion of phosphoric acid crystals R C Compared with the preset percentage threshold R TH Based on the size, make the following decision:

[0061] If R C ≥R TH Then, a heating component 3 is controlled to continuously heat the phosphoric acid in the storage tank 1, and the process returns to step S1 to continuously monitor the liquid level until the real-time crystallization ratio in the storage tank 1 is not higher than the ratio threshold R. TH Then stop heating.

[0062] It should be noted that the preset percentage threshold R THThe size can be adaptively adjusted according to actual conditions.

[0063] when R C ≥ R TH , the proportion of crystal region pixels in n sub-regions can also be arranged in a queue in ascending order, and the conveying assembly 2 is controlled to output phosphoric acid to be heated out of the storage tank 1 through at least one discharge hole 11 near the front end of the queue. The purpose of this method is to preferentially perform in-tank to out-tank cyclic heating of phosphoric acid in areas with little or no crystal in the storage tank 1, so as to avoid or reduce the occurrence of crystallization blocking the discharge hole 11 in areas with a large amount of phosphoric acid crystallization. It should be understood that the crystal monitoring period of the present invention can be set to the aforementioned 12h or shorter, so that the extreme situation that all phosphoric acid solution in the storage tank 1 crystallizes when the temperature is low can be avoided. As the heating continues, the liquid phosphoric acid flows back into the tank after heating, contacts the crystals, the crystals gradually melt into liquid, and the proportion of crystals in the tank continues to decrease until it meets the subsequent feedable condition.

[0064] If R C < R TH , then the feedable stage with a preset time limit is executed. When in the feedable stage and a feeding instruction is received, a conveying assembly 2 is controlled to output the phosphoric acid in the storage tank 1 to a designated phosphate fertilizer production line. The feeding instruction can be generated by a staff at an interactive end, or automatically generated periodically by a program.

[0065] Please refer to Figures 6 to 8 , the phosphoric acid conveying system of the present embodiment includes a conveying assembly 2 matched with the storage tank 1, a heating assembly 3 and an image acquisition module 4. The image acquisition module 4 is fixedly installed on the top cover 13 of the storage tank 1, and is configured to acquire liquid level images of the phosphoric acid inside the storage tank 1 and send the images to a controller, and the controller is configured to control the conveying assembly 2 and the heating assembly 3, so as to realize regular removal of phosphoric acid crystals in the storage tank 1, and supplement and output of phosphoric acid in the storage tank 1. The controller can be electrically connected with the electrical components in the conveying assembly 2, the heating assembly 3 and the image acquisition module 4, so as to implement the aforementioned phosphoric acid conveying method.

[0066] The conveying assembly 2 comprises a first infusion tube 21, a second infusion tube 22, a third infusion tube 23, a conveying pump 25 and a fourth infusion tube 24. One end of the first infusion tube 21 is connected to the discharge hole 11 at the bottom of the storage tank 1, the other end of the first infusion tube 21 is sequentially connected in series with the second infusion tube 22, the heating assembly 3, the third infusion tube 23, the conveying pump 25 and the fourth infusion tube 24, and the end of the fourth infusion tube 24 is connected to the feed hole 12 at the top of the storage tank 1, thereby forming a circulation loop outside the storage tank 1 for the heating assembly 3 to heat phosphoric acid.

[0067] In this embodiment, six discharge holes 11 are evenly distributed circumferentially at the bottom of the side wall of the storage tank 1. Six infusion pipes 21 are provided, each corresponding to one of the discharge holes 11. The same end of each infusion pipe 21 is connected to its corresponding discharge hole 11, and the other end of each infusion pipe 21 is connected to multiple inlets of a multi-way connector 6. The only outlet of the multi-way connector 6 is connected to one end of an infusion pipe 22. Each inlet of the multi-way connector 6 is equipped with a one-way valve 52 to prevent phosphoric acid backflow. A solenoid valve 51 is installed on each infusion pipe 21.

[0068] When it is necessary to output the phosphoric acid solution in the storage tank 1, the controller selects the designated discharge port 11 by the aforementioned method and opens the solenoid valve 51 on the corresponding infusion pipe 21 of these discharge ports 11, so that the phosphoric acid solution can be discharged from these opened infusion pipes 21.

[0069] A solenoid valve 53 is installed on the feed pipe 3. A feed pipe 8 for replenishing phosphoric acid into storage tank 1 is connected to the feed pipe 53 via a tee connector 7 between the solenoid valve 53 and the inlet of the delivery pump 25. A feed solenoid valve 55 is installed on the feed pipe 8. The end of the feed pipe 8 away from the corresponding tee connector 7 can be connected to upstream equipment (such as tank trucks storing phosphoric acid, large storage tanks, etc.) to replenish phosphoric acid into storage tank 1. A solenoid valve 54 is installed on the feed pipe 4. A feed pipe 9 for discharging phosphoric acid to a designated phosphate fertilizer production line is connected to the feed pipe 54 via a tee connector 7 between the solenoid valve 54 and the outlet of the delivery pump 25. A feed solenoid valve 56 is installed on the feed pipe 9. The end of the feed pipe 9 away from the corresponding tee connector 7 can be connected to downstream production lines or equipment (such as production lines for dispensing phosphoric acid into small containers, or reaction vessels using phosphoric acid as raw material, etc.).

[0070] Please see Figure 9 In this embodiment, in addition to heating phosphoric acid (i.e., heating mode), the conveying component 2 can also replenish phosphoric acid solution into the storage tank 1 (i.e., feeding mode) and output the phosphoric acid solution in the storage tank 1 to designated equipment or production line such as the reactor (i.e., supply mode) using only the original single conveying pump 25. In each of the three modes, the controller executes the following control logic.

[0071] In heating mode, the controller simultaneously controls the opening of solenoid valve 1 51, solenoid valve 3 53, solenoid valve 4 54 and conveying pump 25, controls the closing of feeding solenoid valve 55 and feeding solenoid valve 56, and controls the heating component 3 to start heating.

[0072] In the feeding mode, the feeding solenoid valve 55, solenoid valve 4 54 and the delivery pump 25 are opened simultaneously, the solenoid valve 1 51, solenoid valve 3 53 and the feeding solenoid valve 56 are closed, and the heating component 3 is turned off.

[0073] In the feeding mode, the solenoid valve 1 51, solenoid valve 3 53, feeding solenoid valve 56 and conveying pump 25 are opened simultaneously, the feeding solenoid valve 55 and solenoid valve 4 54 are closed, and the heating component 3 is turned off.

[0074] It should be noted that, in addition to the three working modes mentioned above, the transfer pump 25, heating component 3, and each solenoid valve can be in the closed state to ensure the stable storage operation of the storage tank 1.

[0075] Please see Figure 10 In this embodiment, the heating assembly 3 includes a heat exchange shell 31 and a heat exchange tube 32. The heat exchange shell 31 has a shell-side inlet 311 and a shell-side outlet 312 communicating with the interior of the heat exchange shell 31. The heat exchange tube 32 is installed inside the heat exchange shell 31, with its tube-side inlet 321 connected to the second infusion tube 22 and its tube-side outlet 322 connected to the third infusion tube 23.

[0076] In this design, the tube side of the heat exchange tube 32 is used for the passage and heating of the phosphoric acid solution. The heat exchange tube 32 can be distributed in a tortuous (spiral shape as shown in the figure) manner inside the heat exchange shell 31 to increase the tube length and improve the heat exchange effect. The shell side of the heat exchange shell 31 is used for the passage of water (30℃~80℃). Of course, in other embodiments, the heating assembly 3 can also use heat exchangers and / or heat exchange media with other structures.

[0077] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for transporting phosphoric acid in phosphate fertilizer production, characterized in that, Includes the following steps: S1. Periodically obtain images of the phosphoric acid level inside the storage tank (1); S2. Based on target detection, identify the crystallized regions in the liquid surface image, and extract the crystallization features of the liquid surface image according to the distribution of the crystallized regions in the image; S3. Input the crystallization features of the liquid surface image into a prediction model that characterizes the mapping relationship between the crystallization features in the phosphoric acid liquid surface image and the proportion of crystals in phosphoric acid, thereby outputting the current proportion of phosphoric acid crystals R in the storage tank (1). C ; S4. Analysis of the proportion of phosphoric acid crystals R C Compared with the preset percentage threshold R TH Based on the size, make the following decision: If R C ≥R TH Then, a heating component (3) is controlled to continuously heat the phosphoric acid in the storage tank (1), and the process returns to step S1 to continuously monitor the liquid level until the real-time crystallization ratio in the storage tank (1) is not higher than the ratio threshold R. TH Then stop heating; If R C <R TH If the material supply stage is in the preset time limit, and a material supply instruction is received, a conveying component (2) is controlled to output phosphoric acid from the storage tank (1) to the designated phosphate fertilizer production line.

2. The method for transporting phosphoric acid for phosphate fertilizer production according to claim 1, characterized in that, The crystallization characteristics include total crystal area, number of crystals, and average crystal size; the prediction model is trained using a linear regression model.

3. The method for transporting phosphoric acid in phosphate fertilizer production according to claim 1, characterized in that, Before step S1, the real-time liquid level of phosphoric acid in the current storage tank (1) is also obtained; when the real-time liquid level is lower than a rated liquid level value, the conveying component (2) is controlled to continuously replenish phosphoric acid into the storage tank (1) until the real-time liquid level exceeds the rated liquid level value.

4. The method for transporting phosphoric acid in phosphate fertilizer production according to claim 1, characterized in that, In step S2, the liquid surface area in the liquid surface image is further divided into n fan-shaped sub-regions around the center of the storage tank (1), where n ≥ 2; n discharge holes (11) are provided on the storage tank (1), each corresponding to one of the n sub-regions; the projection of each discharge hole (11) along the vertical direction is within the coverage area of ​​the corresponding sub-region; the pixel ratio of the crystallized area in each sub-region is p. i , Where 1≤i≤n, denoted as the number of pixels in the crystalline region within sub-region i. The number of pixels in sub-region i; In step S4, if R C ≥R TH Then, the pixel percentages of the crystallized regions of the n sub-regions are arranged into a queue in ascending order, and the conveying component (2) is controlled to output the phosphoric acid to be heated from at least one discharge hole (11) near the front end of the queue to the outside of the storage tank (1).

5. A phosphoric acid delivery system for phosphate fertilizer production, comprising a delivery assembly (2) matched with a storage tank (1), a heating assembly (3) and an image acquisition module (4); characterized in that, The image acquisition module (4) is fixedly installed on the top cover (13) of the storage tank (1) and is used to acquire the liquid level image of phosphoric acid inside the storage tank (1) and send it to the controller. The controller is used to control the conveying component (2) and the heating component (3) to realize the periodic removal of phosphoric acid crystals in the storage tank (1) and the replenishment and output of phosphoric acid in the storage tank (1). The controller applies a phosphoric acid conveying method for phosphate fertilizer production as described in any one of claims 1 to 4.

6. A phosphoric acid delivery system for phosphate fertilizer production according to claim 5, characterized in that, The conveying assembly (2) includes a first infusion pipe (21), a second infusion pipe (22), a third infusion pipe (23), a conveying pump (25), and a fourth infusion pipe (24). One end of the first infusion pipe (21) is connected to the discharge hole (11) at the bottom of the storage tank (1). The other end of the first infusion pipe (21) is connected in series with the second infusion pipe (22), the heating assembly (3), the third infusion pipe (23), the conveying pump (25), and the fourth infusion pipe (24). The end of the fourth infusion pipe (24) is connected to the inlet hole (12) at the top of the storage tank (1), thereby forming a circulation loop outside the storage tank (1) for heating phosphoric acid by the heating assembly (3).

7. A phosphoric acid delivery system for phosphate fertilizer production according to claim 6, characterized in that, The bottom of the side wall of the storage tank (1) is provided with multiple discharge holes (11) along the circumferential direction; multiple infusion pipes (21) are provided, and each corresponds to one of the multiple discharge holes (11); the same end of each infusion pipe (21) is connected to its corresponding discharge hole (11), and the other end of each infusion pipe (21) is connected to multiple inlets of a multi-port connector (6); the only outlet of the multi-port connector (6) is connected to one end of the infusion pipe (22); the multiple inlets of the multi-port connector (6) are provided with one-way valves (52) to prevent phosphoric acid backflow; each infusion pipe (21) is provided with a solenoid valve (51).

8. A phosphoric acid delivery system for phosphate fertilizer production according to claim 7, characterized in that, The infusion pipe three is equipped with a solenoid valve three (53). The pipeline between the solenoid valve three (53) and the inlet of the delivery pump (25) is connected to a feed pipe (8) for replenishing phosphoric acid into the storage tank (1) through a three-way connector (7). The feed pipe (8) is equipped with a feed solenoid valve (55). The infusion pipe four is equipped with a solenoid valve four (54). The pipeline between the solenoid valve four (54) and the outlet of the delivery pump (25) is connected to a feed pipe (9) for outputting phosphoric acid to a designated phosphate fertilizer production line through a three-way connector (7). The feed pipe (9) is equipped with a feed solenoid valve (56).

9. A phosphoric acid delivery system for phosphate fertilizer production according to claim 8, characterized in that, The controller is also used for: When it is necessary to remove phosphoric acid crystals in the storage tank (1), the solenoid valves 1 (51), 3 (53), 4 (54) and the delivery pump (25) are opened simultaneously, the feeding solenoid valve (55) and the supply solenoid valve (56) are closed, and the heating component (3) is turned on to heat. When it is necessary to output phosphoric acid from the storage tank (1), the solenoid valve 1 (51), solenoid valve 3 (53), feeding solenoid valve (56) and delivery pump (25) are opened simultaneously, the feeding solenoid valve (55) and solenoid valve 4 (54) are closed, and the heating component (3) is turned off. When phosphoric acid needs to be added to the storage tank (1), the feeding solenoid valve (55), solenoid valve four (54) and the delivery pump (25) are opened simultaneously, the solenoid valve one (51), solenoid valve three (53) and the feeding solenoid valve (56) are closed, and the heating component (3) is turned off.

10. A phosphoric acid delivery system for phosphate fertilizer production according to claim 6, characterized in that, The heating assembly (3) includes a heat exchange shell (31) and a heat exchange tube (32); the heat exchange shell (31) is provided with a shell-side inlet (311) and a shell-side outlet (312) communicating with the inside of the heat exchange shell (31); the heat exchange tube (32) is installed inside the heat exchange shell (31), and the tube-side inlet (321) of the heat exchange tube (32) is connected to the second infusion tube (22), and the tube-side outlet (322) of the heat exchange tube (32) is connected to the third infusion tube (23).

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