A low-concentration phosphorus-containing wastewater recycling system for producing PBO fibers

Abstract

This application provides a low-concentration phosphorus-containing wastewater recycling system for PBO fiber production, including a spinning washing system, a washing tank, a wastewater storage tank, a phosphorus removal system, and a filter press. The washing tank is located below the spinning washing system. The inlet of the wastewater storage tank is connected to the outlet of the washing tank. The phosphorus removal system includes a sludge tank and a clear water tank. The outlet of the wastewater storage tank is connected to the inlet of the sludge tank, and the outlet of the clear water tank is connected to the spinning washing system. The filter press is located above the water storage tank, and its inlet is connected to the outlet of the sludge tank. The outlet of the water separated by the filter press is connected to the wastewater storage tank. This system allows for the treatment of low-concentration phosphorus-containing wastewater generated during PBO fiber production. The treated clear water can be reused in the spinning washing system for washing PBO fibers, while the water separated from the treated phosphorus-containing sludge by the filter press can be returned to the wastewater storage tank for further treatment, thus achieving zero discharge of phosphorus-containing wastewater.

Description

Technical Field

[0001] This utility model relates to the field of phosphorus-containing wastewater recycling technology, and in particular to a low-concentration phosphorus-containing wastewater recycling system for the production of PBO fibers. Background Technology

[0002] PBO fiber, also known as polyphenylene benzodioxazole fiber, possesses excellent properties such as high strength, high modulus, high temperature resistance, and flame retardancy. Its fiber strength can reach 5800 MPa, its modulus is as high as 280 GPa, it does not burn in air, its limiting oxygen index is 68%, and its thermal decomposition temperature is as high as 650℃. Due to its superior properties, PBO fiber is widely used in aerospace, armor protection, sports equipment, and heat protection fields.

[0003] In the preparation of PBO fibers, polyphosphoric acid and phosphorus pentoxide are mostly used as solvents. After the polymer undergoes multiple washing stages during spinning, high-performance PBO fibers are obtained. For example, an existing patent discloses a process for producing poly(p-phenylenebenzodioxazole) PBO fibers. In step C of this process, the fibers enter a coagulation pan with a draw ratio of 10-40, and then coagulate in a first coagulation tank to obtain virgin fibers. The virgin fibers then enter a second coagulation tank. The coagulation solution in the coagulation pan is an aqueous phosphoric acid solution with a mass concentration of 10-30%; the coagulation solution in the first coagulation tank is an aqueous phosphoric acid solution with a mass concentration of 5-20%; and the coagulation solution in the second coagulation tank is an aqueous phosphoric acid solution with a concentration of 0-10%. In step D, the fibers are washed and coagulated again in a washing tank with a water flow rate of 50-500 L / h. However, the water after washing still contains a small amount of phosphorus. Directly discharging the large amount of low-concentration phosphorus-containing wastewater would cause environmental pollution, while directly sending it to a wastewater treatment system would significantly increase the treatment pressure and cost of the subsequent treatment system. Utility Model Content

[0004] The purpose of this application is to provide a low-concentration phosphorus-containing wastewater recycling system for the production of PBO fibers, so as to solve the technical problem that a large amount of low-concentration phosphorus-containing wastewater is generated in the process of producing PBO fibers in the prior art.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] This application provides a low-concentration phosphorus-containing wastewater recycling system for PBO fiber production, comprising: a spinning washing system, a washing tank, a wastewater storage tank, a phosphorus removal system, and a filter press. The washing tank is located below the spinning washing system and is used to receive the phosphorus-containing wastewater after the spinning washing system washes the PBO fibers. The inlet of the wastewater storage tank is connected to the outlet of the washing tank for quantitatively receiving the low-concentration phosphorus-containing wastewater from the washing tank. The phosphorus removal system includes a sludge tank and a clear water tank, with their tops connected. The outlet of the wastewater storage tank is connected to the inlet of the sludge tank, and the outlet of the clear water tank is connected to the spinning washing system. The filter press is located above the water storage tank, with its inlet connected to the outlet of the sludge tank, and the outlet of the water separated by the filter press connected to the wastewater storage tank.

[0007] In some embodiments, a first total phosphorus analyzer and a first pH meter are provided on the wastewater storage tank, respectively for detecting the phosphorus content and pH value of the phosphorus-containing wastewater in the wastewater storage tank.

[0008] In some embodiments, the outlet of the wastewater storage tank is located at the bottom of the wastewater storage tank, and a first transfer pump and a first flow meter are provided on the connecting pipeline between the outlet of the wastewater storage tank and the inlet of the sludge pond.

[0009] In some embodiments, the outlet of the sludge tank is located at the bottom of the sludge tank, and a second delivery pump is provided on the connecting pipeline between the outlet of the sludge tank and the inlet of the filter press.

[0010] In some embodiments, a second total phosphorus meter and a second pH meter are provided on the clear water tank for detecting the water quality in the clear water tank.

[0011] In some embodiments, the outlet of the clear water tank is located at the bottom of the clear water tank, and a third delivery pump is provided on the connecting pipeline between the outlet of the clear water tank and the spinning washing system.

[0012] In some embodiments, the outlet of the washing tank is located at the bottom of the washing tank, and a fourth delivery pump is provided on the connecting pipeline between the outlet of the washing tank and the inlet of the wastewater storage tank.

[0013] In some embodiments, it further includes: a phosphorus removal agent tank, which is connected to a sludge tank via a pipeline, and a fifth transfer pump and a second flow meter are provided on the pipeline.

[0014] In some embodiments, the system further includes a control system, which is communicatively connected to a first total phosphorus analyzer, a first pH meter, a first delivery pump, a first flow meter, a second delivery pump, a third delivery pump, a second total phosphorus analyzer, a second pH meter, a fourth delivery pump, a fifth delivery pump, and a second flow meter.

[0015] In some embodiments, the control system is configured to adjust the flow data of the second flow meter based on the received data from the first total phosphorus analyzer, the first pH meter, and the first flow meter.

[0016] Based on the above technical solution, the low-concentration phosphorus-containing wastewater recycling system for PBO fiber production of this application has at least the following beneficial technical effects:

[0017] The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production of this application includes a spinning washing system, a washing tank, a wastewater storage tank, a phosphorus removal system, and a filter press. The washing tank is located below the spinning washing system and is used to receive the low-concentration phosphorus-containing wastewater after the spinning washing system washes the PBO fibers. The inlet of the wastewater storage tank is connected to the outlet of the washing tank for quantitatively receiving the phosphorus-containing wastewater from the washing tank. The phosphorus removal system includes a sludge tank and a clear water tank, with their tops connected. The outlet of the wastewater storage tank is connected to the inlet of the sludge tank, and the outlet of the clear water tank is connected to the spinning washing system. The filter press is located above the water storage tank, with its inlet connected to the outlet of the sludge tank, and the outlet of the water separated by the filter press connected to the wastewater storage tank. Furthermore, the recycling system described in this application can treat low-concentration phosphorus-containing wastewater generated during the production of PBO fibers through a phosphorus removal system. The treated water can then be reused in the spinning and washing system for washing PBO fibers. The phosphorus-containing sludge from the sludge tank is separated into sludge blocks and water by a filter press. The sludge blocks can be treated as phosphorus-containing solid hazardous waste, while the separated water can be returned to the wastewater storage tank for further treatment, thus achieving zero discharge of phosphorus-containing wastewater. Simultaneously, this significantly reduces water consumption for PBO fiber washing and substantially lowers production costs.

[0018] Furthermore, the low-concentration phosphorus-containing wastewater recycling system for PBO fiber production in this embodiment of the application also includes a control system. The control system is communicatively connected to a first total phosphorus analyzer, a first pH meter, a first transfer pump, a first flow meter, a second transfer pump, a third transfer pump, a second total phosphorus analyzer, a second pH meter, a fourth transfer pump, a fifth transfer pump, and a second flow meter. The control system is at least configured to adjust the flow rate data of the second flow meter based on received data from the first total phosphorus analyzer, the first pH meter, and the first flow meter. This allows the control system to automatically adjust phosphorus removal process parameters based on received data such as the influent flow rate from the first flow meter, the influent total phosphorus from the first total phosphorus analyzer, and the pH from the first pH meter. The control system can also communicate with the first, second, third, fourth, and fifth transfer pumps to automatically control the start and stop of each transfer pump.

[0019] In addition to achieving fully automated recovery of low-concentration phosphorus-containing wastewater, it can also meet the processing needs of PBO fiber production units under different start-up loads, thereby improving production efficiency. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a structural diagram of the low-concentration phosphorus-containing wastewater recycling system for the production of PBO fibers in this application.

[0022] Figure 2 This is a process connection diagram of the control system in the low-concentration phosphorus-containing wastewater recycling system for the production of PBO fibers in this application.

[0023] In the diagram: 1-Spinning washing system; 2-Washing tank; 21-Fourth transfer pump; 3-Wastewater storage tank; 31-First total phosphorus analyzer; 32-First pH meter; 33-First transfer pump; 34-First flow meter; 4-Phosphorus removal system; 41-Sludge tank; 42-Clear water tank; 411-Second transfer pump; 421-Third transfer pump; 422-Second total phosphorus analyzer; 423-Second pH meter; 5-Filter press; 6-Phosphorus removal agent tank; 61-Fifth transfer pump; 62-Second flow meter. Detailed Implementation

[0024] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0025] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0026] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application 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 application.

[0027] 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 application, "multiple" means two or more, unless otherwise explicitly specified.

[0028] The technical solution of this application will now be described in detail with reference to the accompanying drawings.

[0029] Please refer to Figure 1 , Figure 1 A structural diagram of a low-concentration phosphorus-containing wastewater recycling system for PBO fiber production is provided. This application provides a low-concentration phosphorus-containing wastewater recycling system for PBO fiber production, comprising: a spinning washing system 1, a washing tank 2, a wastewater storage tank 3, a phosphorus removal system 4, and a filter press 5. The spinning washing system 1 refers to the system used in the PBO fiber production process for washing to obtain nascent PBO fiber filaments.

[0030] The washing tank 2 is located below the spinning washing system 1 and is used to receive the low-concentration phosphorus-containing wastewater after the spinning washing system 1 washes the PBO fibers. The washing tank 2 is used to receive and store the water after washing by the spinning washing system 1. Positioning the washing tank 2 below the spinning washing system 1 allows for direct collection of the low-concentration phosphorus-containing wastewater by gravity. The washing tank 2 also acts as a buffer for subsequent phosphorus removal treatment of the low-concentration phosphorus-containing wastewater, preventing excessive flow of the wastewater from entering the wastewater storage tank 3 and the phosphorus removal system 4, which could lead to poor treatment results.

[0031] The inlet of wastewater storage tank 3 is connected to the outlet of washing tank 2, and is used to quantitatively receive low-concentration phosphorus-containing wastewater from washing tank 2. Low-concentration phosphorus-containing wastewater can be quantitatively supplied into wastewater storage tank 3 according to production process requirements to avoid excessive flow of low-concentration phosphorus-containing wastewater entering wastewater storage tank 3, which would affect the subsequent phosphorus removal effect.

[0032] The phosphorus removal system 4 includes a sludge tank 41 and a clear water tank 42, with their tops connected. The outlet of the wastewater storage tank 3 is connected to the inlet of the sludge tank 41, allowing the low-concentration phosphorus-containing wastewater in the wastewater storage tank 3 to enter the sludge tank 41 for phosphorus removal treatment. The outlet of the clear water tank 42 is connected to the spinning washing system 1. In some embodiments, the sludge tank 41 contains a phosphorus removal agent. After treatment with the phosphorus removal agent in the sludge tank 41, the low-concentration phosphorus-containing wastewater forms phosphorus-containing sludge and clear water. The clear water can enter the clear water tank 42 from the top of the sludge tank 41, while the resulting phosphorus-containing sludge sludge is deposited at the bottom of the sludge tank 41.

[0033] Filter press 5 is located above wastewater storage tank 3. The inlet of filter press 5 is connected to the outlet of sludge tank 41, so that phosphorus-containing sludge treated with phosphorus removal agent in sludge tank 41 can be transported to filter press 5 for solid-liquid separation. The outlet of the water separated by filter press 1 is connected to wastewater storage tank 3.

[0034] In the technical solution of this application embodiment, the low-concentration phosphorus-containing wastewater generated during the production of PBO fibers can be treated by a phosphorus removal system through the recycling system of this application. The treated clean water can enter the spinning washing system 1 through the clean water tank 42 for further washing of PBO fibers. The phosphorus-containing sludge after treatment in the sludge tank enters the filter press 5 through the sludge tank 41. After solid-liquid separation treatment in the filter press 5, it is separated into sludge blocks and water. The sludge blocks can be treated as phosphorus-containing solid hazardous waste, and the separated water can be returned to the wastewater storage tank 3 for further recycling, thereby achieving zero discharge of phosphorus-containing wastewater. At the same time, it can greatly save water consumption for washing PBO fibers and significantly reduce production costs.

[0035] Preferably, the low-concentration phosphorus-containing wastewater recycling method for PBO fiber production in this application further includes: a phosphorus removal agent tank 6, which contains phosphorus removal agents for reacting with the low-concentration phosphorus-containing wastewater. The phosphorus removal agent tank 6 is connected to a sludge tank 41 via a pipeline, so that the required amount of phosphorus removal agent can be added to the sludge tank 41. A fifth transfer pump 61 and a second flow meter 62 are provided on the pipeline. This allows for precise control of the amount of phosphorus removal agent added by controlling the fifth transfer pump 61 and the second flow meter 62 when needed, avoiding excessive or insufficient addition of phosphorus removal agent that would result in substandard treated water quality.

[0036] Preferably, a first total phosphorus analyzer 31 and a first pH meter 32 are provided on the wastewater storage tank 3 to detect the phosphorus content and pH value of the phosphorus-containing wastewater in the wastewater storage tank 3, respectively. In some embodiments, the first total phosphorus analyzer 31 and the first pH meter 32 are connected to a control system so that the control system can monitor the total phosphorus content and pH value of the low-concentration phosphorus-containing wastewater in the wastewater storage tank 3 in real time.

[0037] Preferably, the outlet of the wastewater storage tank 3 is located at the bottom of the wastewater storage tank 3, and a first transfer pump 33 and a first flow meter 34 are provided on the connecting pipeline between the outlet of the wastewater storage tank 3 and the inlet of the sludge tank 41. This allows for precise control of the flow rate of wastewater entering the phosphorus removal system 4 based on the first transfer pump 33 and the first flow meter 34. In some embodiments, the first transfer pump 33 and the first flow meter 34 are connected to a control system so that the control system can monitor the flow rate of wastewater entering the phosphorus removal system 4 from the wastewater storage tank 3 in real time, and thus precisely control the amount of phosphorus removal agent added based on the phosphorus content in the wastewater and the wastewater flow rate.

[0038] Preferably, the outlet of the sludge tank 41 is located at the bottom of the sludge tank 41. The sludge formed after the low-concentration phosphorus-containing wastewater in the sludge tank 41 reacts with the phosphorus removal agent settles at the bottom of the sludge tank 41. The bottom-positioned outlet of the sludge tank 41 allows for timely transport of the sludge deposited at the bottom of the sludge tank 41 to the filter press 5. A second transfer pump 411 is installed on the connecting pipe between the outlet of the sludge tank 41 and the inlet of the filter press 5. This allows the sludge at the bottom of the sludge tank 41 to be transported to the filter press 5 for further solid-liquid separation treatment via the second transfer pump 411.

[0039] Preferably, the clear water obtained after the low-concentration phosphorus-containing wastewater reacts with the phosphorus removal agent in the sludge tank 41 overflows into the clear water tank 42. A second total phosphorus meter 422 and a second pH meter 423 are installed in the clear water tank 42 to detect the water quality. In some embodiments, the outlet of the clear water tank 42 is located at the bottom of the clear water tank 42, and a third transfer pump 421 is installed on the connecting pipeline between the outlet of the clear water tank 42 and the spinning washing system 1. This allows the third transfer pump 421 to be activated to transfer the clear water to the spinning washing system 1 for continued recycling when the water quality in the clear water tank 42 meets the requirements.

[0040] Preferably, the outlet of the washing tank 2 is located at the bottom of the washing tank 2, and a fourth transfer pump 21 is installed on the connecting pipeline between the outlet of the washing tank 2 and the inlet of the wastewater storage tank 3. This allows the wastewater to be quantitatively delivered to the wastewater storage tank 3 according to the requirements of the production process via the fourth transfer pump 21.

[0041] Preferably, the low-concentration phosphorus-containing wastewater recycling system for PBO fiber production of this application further includes: a control system 7, which is communicatively connected to a first total phosphorus analyzer 31, a first pH meter 32, a first transfer pump 33, a first flow meter 34, a second transfer pump 411, a third transfer pump 421, a second total phosphorus analyzer 422, a second pH meter 423, a fourth transfer pump 21, a fifth transfer pump 61, and a second flow meter 62. The control system 7 can receive data from the first total phosphorus analyzer 31 and the first pH meter 32 to monitor the phosphorus content and pH value of the low-concentration wastewater in the wastewater storage tank 3. The control system 7 can also receive data from the second total phosphorus analyzer 422 and the second pH meter 423 to monitor the phosphorus content and pH value of the clear water in the clear water tank 42 to determine whether the treated clear water quality meets the standards. The control system 7 is communicatively connected to the first transfer pump 33 and the first flow meter 34. The first transfer pump 33 can be a variable frequency transfer pump, so that the control system 7 can control the transfer capacity of the first transfer pump 33 based on the flow parameters fed back from the first flow meter 34. The control system 7 is also communicatively connected to the fifth transfer pump 61 and the second flow meter 62. The fifth transfer pump 61 can be a variable frequency transfer pump, so that the control system 7 can control the transfer capacity of the fifth transfer pump 61 based on the required dosage of the dephosphorizing agent and the flow parameters fed back from the second flow meter 62, thereby precisely controlling the amount of dephosphorizing agent added. The second transfer pump 411, the third transfer pump 421, the fourth transfer pump 21, and the fifth transfer pump 61 can all be variable frequency transfer pumps. The control system 7 is communicatively connected to the second transfer pump 411, the third transfer pump 421, and the fourth transfer pump 21, so that the control system 7 can control the second transfer pump 411, the third transfer pump 421, and the fourth transfer pump 21 based on the requirements of the production process.

[0042] In some embodiments, the control system 7 is configured to adjust the flow rate data of the second flow meter 62 based on the received data from the first total phosphorus analyzer 31, the first pH meter 32, and the first flow meter 34. Preferably, the control system can be a PLC system. This allows the control system to automatically adjust the phosphorus removal process parameters based on data such as the influent flow rate of the first flow meter 34, the influent total phosphorus of the first total phosphorus analyzer 31, and the pH of the first pH meter 32. This not only enables fully automated recovery of low-concentration phosphorus-containing wastewater but also meets the processing requirements of the PBO fiber production unit under different start-up loads, thereby improving production efficiency.

[0043] The low-concentration phosphorus-containing wastewater recycling system of this application can recycle and treat low-concentration phosphorus-containing wastewater generated during the production of PBO fibers, achieving zero discharge of phosphorus-containing wastewater. Simultaneously, it can save water consumption in the washing step of PBO fibers, significantly reducing production costs.

[0044] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A low-concentration phosphorus-containing wastewater recycling system for the production of PBO fibers, characterized in that, include: Spinning water washing system (1); The washing tank (2) is located below the spinning washing system (1) and is used to receive the low-concentration phosphorus-containing wastewater after the spinning washing system (1) washes the PBO fibers. Wastewater storage tank (3), the inlet of which is connected to the outlet of the washing tank (2), is used to quantitatively receive low-concentration phosphorus-containing wastewater from the washing tank (2); The phosphorus removal system (4) includes a sludge tank (41) and a clear water tank (42). The tops of the sludge tank (41) and the clear water tank (42) are connected. The outlet of the wastewater storage tank (3) is connected to the inlet of the sludge tank (41), and the outlet of the clear water tank (42) is connected to the spinning washing system (1). A filter press (5) is located above the wastewater storage tank (3). The inlet of the filter press (5) is connected to the outlet of the sludge tank (41), and the outlet of the water separated by the filter press (1) is connected to the wastewater storage tank (3).

2. The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production according to claim 1, characterized in that, The wastewater storage tank (3) is equipped with a first total phosphorus analyzer (31) and a first pH meter (32), which are used to detect the phosphorus content and pH value of the phosphorus-containing wastewater in the wastewater storage tank (3), respectively.

3. The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production according to claim 2, characterized in that, The outlet of the wastewater storage tank (3) is located at the bottom of the wastewater storage tank (3), and a first delivery pump (33) and a first flow meter (34) are provided on the connecting pipeline between the outlet of the wastewater storage tank (3) and the inlet of the sludge pool (41).

4. The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production according to claim 1, characterized in that, The outlet of the sludge tank (41) is located at the bottom of the sludge tank (41), and a second delivery pump (411) is provided on the connecting pipeline between the outlet of the sludge tank (41) and the inlet of the filter press (5).

5. The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production according to claim 1, characterized in that, A second total phosphorus meter (422) and a second pH meter (423) are provided on the clear water tank (42) for detecting the water quality in the clear water tank (42).

6. The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production according to claim 5, characterized in that, The outlet of the clear water tank (42) is located at the bottom of the clear water tank (42), and a third delivery pump (421) is provided on the connecting pipeline between the outlet of the clear water tank (42) and the spinning washing system (1).

7. The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production according to claim 1, characterized in that, The outlet of the washing tank (2) is located at the bottom of the washing tank (2), and a fourth delivery pump (21) is provided on the connecting pipeline between the outlet of the washing tank (2) and the inlet of the wastewater storage tank (3).

8. The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production according to any one of claims 1 to 7, characterized in that, Also includes: A phosphorus removal agent tank (6) is connected to the sludge tank (41) via a pipeline, and a fifth transfer pump (61) and a second flow meter (62) are provided on the pipeline.

9. The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production according to claim 8, characterized in that, Also includes: The control system (7) is connected in communication with the first total phosphorus analyzer (31), the first pH meter (32), the first transfer pump (33), the first flow meter (34), the second transfer pump (411), the third transfer pump (421), the second total phosphorus analyzer (422), the second pH meter (423), the fourth transfer pump (21), the fifth transfer pump (61), and the second flow meter (62).

10. The low-concentration phosphorus-containing wastewater recycling system for PBO fiber production according to claim 9, characterized in that, The control system (7) is configured at least to adjust the flow data of the second flow meter (62) based on the data received from the first total phosphorus analyzer (31), the first pH meter (32) and the first flow meter (34).

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