Recycling and cleaning system for caprolactam in filter

Abstract

The utility model discloses a recovery cleaning system for caprolactam in a filter in the technical field of filter cleaning, which comprises a filter, a flushing pipe, a collecting tank, a steam pipe and a nitrogen pipe, the collecting tank is a storage tank of a tank car, the filter is communicated with the collecting tank, and the flushing pipe, the steam pipe and the nitrogen pipe are all hermetically communicated with an exhaust pipe of the filter. The caprolactam in the filter is collected by using a tank truck, continuous inspection by personnel is not needed, and the transfer work of the caprolactam in the filter can be completed only by opening the exhaust pipe, the feeding pipe, the discharging pipe, the recycling pipe, the flushing pipe, the blending pipe, the steam pipe, the heating pipe and the nitrogen pipe according to steps; in the whole process, caprolactam does not make contact with the outside, caprolactam is convenient to transfer and store, manual carrying is not needed in the whole process, meanwhile, the filter and the filter element in the filter can be effectively and preliminarily cleaned in time, the filter element is prevented from being solidified and blocked, and convenience is brought to follow-up cleaning.

Description

Technical Field

[0001] This utility model relates to the field of filter cleaning technology, and in particular to a system for recovering and cleaning caprolactam in filters. Background Technology

[0002] The main raw material for nylon 6 polymerization is caprolactam. The quality of caprolactam directly affects the final quality of nylon 6 chips. Therefore, caprolactam must pass through 1-2 high-precision filters before entering the filter to remove fine impurities.

[0003] After a period of use, the filter element inside the filter needs to be cleaned to ensure smooth flow of the caprolactam solution inside the filter and maintain good filtration performance.

[0004] The filter contains caprolactam, which requires a temperature above 80 degrees Celsius to maintain its flow. Currently, when cleaning the filter, both the inlet and outlet valves must be closed. The caprolactam inside the filter is then drained and recovered. During recovery, the caprolactam is collected at the bottom of the filter using a large iron drum or similar container, transported to a designated recovery point, and finally transported to a higher pipeline. The recovered caprolactam solution is then collected via a hopper. Because this recovered caprolactam has been exposed to air and the external environment, it requires further purification and refining processes before it can be reused.

[0005] This recycling process is time-consuming and labor-intensive. Because the caprolactam solution is hot, it can easily burn workers during handling. Working for extended periods within the high-temperature radiation range of the filter can also easily lead to heatstroke. Furthermore, since other containers are used to hold the caprolactam, it is easy to splash the solution around and pollute the environment. The caprolactam can also cause localized oxidation due to contact with air. In addition, the large amount of air entering the filter can cause the caprolactam inside the filter to cool down and oxidize and condense. This results in the inability to completely remove the lumpy caprolactam inside the filter, especially on the filter element mesh, where a large amount of caprolactam will remain, making it very difficult to clean even after removal.

[0006] Meanwhile, because the inlet and outlet pipes of the filter may also be blocked, the flow of caprolactam inside the filter is not smooth, and the discharge rate is greatly reduced. Cleaning the filter once takes at least two hours, which is labor-intensive and dangerous.

[0007] Based on this, the present invention designs a caprolactam recovery and cleaning system for filters to solve the above problems. Utility Model Content

[0008] The purpose of this invention is to provide a system for recovering and cleaning caprolactam inside a filter. This system eliminates the need for manual handling of smaller containers; instead, a tanker truck is used to collect the caprolactam from the filter. The entire collection process requires no continuous monitoring. Simply follow the steps of opening the exhaust pipe, feed pipe, discharge pipe, recovery pipe, flushing pipe, mixing pipe, steam pipe, heating pipe, and nitrogen pipe to complete the transfer of caprolactam from the filter. Throughout the process, the caprolactam does not come into contact with the outside environment; it is only temporarily stored in the collection tank. The caprolactam transfer is convenient, the entire process requires no manual handling, and it can be directly integrated with subsequent extraction processes. Simultaneously, it provides timely and effective preliminary cleaning of the filter and its internal filter element, preventing filter element solidification and clogging, thus facilitating subsequent cleaning.

[0009] This invention is achieved as follows: a system for recovering and cleaning caprolactam in a filter, comprising:

[0010] Filters, flushing pipes, collection tanks, steam pipes, and nitrogen pipes;

[0011] The filter is a closed tank with an exhaust pipe at the top and a discharge pipe at the top. The bottom of the filter is connected to an inlet pipe and a recovery pipe. Each of the inlet pipe, discharge pipe, and recovery pipe is equipped with a separate valve.

[0012] The collection tank is a storage tank of a tank truck. The top of the collection tank is equipped with a feed inlet. The outlet of the recovery pipe is detachably inserted into the feed inlet. The bottom of the collection tank is also connected to a transfer pump. The outlet of the transfer pump is sealed to a storage tank.

[0013] The flushing pipe, steam pipe, and nitrogen pipe are all separate, closed pipelines, and are all sealed and connected to the exhaust pipe. The filter is sealed and connected to the demineralized water pipeline via the flushing pipe, and to the steam pipeline via the steam pipe.

[0014] The rear end of the steam pipe is also connected to a heating pipe via a tee, and the rear end of the heating pipe is connected to the recovery pipe.

[0015] The rear end of the flushing pipe is also connected to a mixing pipe, and the outlet of the mixing pipe is sealed and connected to the inlet.

[0016] Furthermore, each of the exhaust pipe, feed pipe, discharge pipe, recovery pipe, flushing pipe, mixing pipe, steam pipe, heating pipe, and nitrogen pipe is equipped with a valve that can be controlled individually.

[0017] Furthermore, a pressure gauge is installed on the nitrogen pipe, and a pressure gauge is also installed at the rear end of the delivery pump.

[0018] Furthermore, a pipe connector is provided at the front end of the delivery pump. The pipe connector is a quick connector for water pipes, and the delivery pump is detachably connected to the storage tank of the collection tank through the pipe connector.

[0019] A valve is installed at the front end of the pipe joint, and a valve is also installed at the rear end of the delivery pump.

[0020] The beneficial effects of this utility model are: 1. This utility model uses a closed collection tank to temporarily store and transfer caprolactam inside the filter, and the whole process does not require the use of other containers, making it easy to transport, while also effectively preventing caprolactam from being contaminated by the external environment.

[0021] 2. While collecting caprolactam inside the filter, this device also uses steam and water to flush the inside of the filter, diluting the high concentration of caprolactam inside the filter into an aqueous solution. This effectively prevents the caprolactam from directly oxidizing and condensing, and also increases the fluidity of the caprolactam, making subsequent transportation and transfer of the liquid more convenient.

[0022] 3. This device significantly reduces the time required for the entire filter cleaning process, greatly reduces labor intensity, and significantly improves work efficiency. It is also easy to use and does not require personnel to stand near the high-temperature filter, thus avoiding burns. Caprolactam does not come into contact with the external environment, effectively preventing caprolactam solution from splashing and contaminating the environment. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is a schematic diagram of the structure of this utility model.

[0025] The attached diagram lists the components represented by each number as follows:

[0026] 1-Filter, 11-Exhaust pipe, 12-Inlet pipe, 13-Outlet pipe, 14-Recovery pipe, 2-Flushing pipe, 21-Blending pipe, 3-Collection tank, 31-Pipe fitting, 32-Inlet, 33-Transfer pump, 4-Steam pipe, 41-Heating pipe, 5-Nitrogen pipe, 51-Pressure gauge. Detailed Implementation

[0027] Please see Figure 1 As shown, this utility model provides a system for recovering and cleaning caprolactam in a filter. To better understand the above technical solution, the following will describe the above technical solution in detail with reference to the accompanying drawings and specific embodiments.

[0028] In a specific embodiment of the technical solution of this utility model:

[0029] Includes filter 1, flushing pipe 2, collection tank 3, steam pipe 4, and nitrogen pipe 5;

[0030] Filter 1 is a closed tank. Filter 1 is equipped with an exhaust pipe 11 at the top and a discharge pipe 13 at the top. Filter 1 is also connected to an inlet pipe 12 and a recovery pipe 14 at the bottom. Each of the inlet pipe 12, discharge pipe 13, and recovery pipe 14 is equipped with a separate valve. The discharge pipe 13 is connected to the polymerization tower of caprolactam, and the inlet pipe 12 is sealed to the outlet of the caprolactam delivery pump. Filter 1 is equipped with a filter element. When the filter element's pores become clogged, it needs to be disassembled and cleaned. At the same time, the tank of filter 1 also needs to be cleaned.

[0031] The bottom of filter 1 is also equipped with a slag discharge pipe, which is used to clean and discharge solid impurities inside filter 1. The slag discharge pipe is a common device, and a valve needs to be installed on the slag discharge pipe. This is conventional technology in the field and will not be described in detail here.

[0032] The collection tank 3 serves as the storage tank for the tanker truck. An inlet 32 ​​is located at the top of the collection tank 3, and the outlet of the recovery pipe 14 is detachably inserted into the inlet 32. A transfer pump 33 is connected to the bottom of the collection tank 3. The outlet of the transfer pump 33 is sealed to a storage tank, typically a caprolactam extraction water storage tank, facilitating the effective recovery of the caprolactam aqueous solution from the filter 1. This structure not only prevents the caprolactam in the filter 1 from oxidizing due to contact with oxygen but also allows direct delivery into the extraction water storage tank for convenient recycling and reuse. A pipe connector 31, a quick-connect fitting for water pipes, is located at the front end of the transfer pump 33. A pressure gauge 51 is also installed at the rear end of the transfer pump 33. This allows for monitoring the pressure on the pipeline at the rear end of the transfer pump 33, thus indicating whether the valve is closed and whether the caprolactam inside the collection tank 3 has been completely transferred.

[0033] The transfer pump 33 is detachably connected to the storage tank of the collection tank 3 via the pipe joint 31; a valve is provided at the front end of the pipe joint 31 and a valve is also provided at the rear end of the transfer pump 33, which facilitates the movement of the tank truck and enables the collection tank 3 to receive and recycle different filters 1. It is convenient to use and easy to transport.

[0034] The flushing pipe 2, steam pipe 4, and nitrogen pipe 5 are all separate, closed pipes. They are all sealed and connected to the exhaust pipe 11. The filter 1 is sealed and connected to the demineralized water pipeline through the flushing pipe 2 and to the steam pipeline through the steam pipe 4, allowing for 0.5 bar steam purging. The filter 1 is sealed and connected to the nitrogen pipeline through the nitrogen pipe 5. The nitrogen pipeline requires 6 bar of nitrogen gas. A pressure gauge 51 is also installed on the nitrogen pipe 5 to ensure that the filter 1 is kept in an oxygen-free state, preventing the caprolactam inside the filter 1 from condensing upon contact with oxygen, effectively preventing complete blockage of the filter element. Furthermore, the filter 1 is pre-purged with steam and diluted with water, facilitating subsequent cleaning.

[0035] The rear end of the steam pipe 4 is also connected to the heating pipe 41 via a tee, and the rear end of the heating pipe 41 is connected to the recovery pipe 14.

[0036] The rear end of the flushing pipe 2 is also connected to the mixing pipe 21. The outlet of the mixing pipe 21 is sealed and connected to the feed inlet 32. The exhaust pipe 11, feed pipe 12, discharge pipe 13, recovery pipe 14, flushing pipe 2, mixing pipe 21, steam pipe 4, heating pipe 41 and nitrogen pipe 5 are all equipped with valves that can be controlled individually. The valves on each pipe do not affect each other, ensuring that the valves on each pipe can control the opening or closing of the pipe.

[0037] The valve outlet end on the heating pipe 41 and the valve outlet end of the recovery pipe 14 are both connected to the feed inlet 32 ​​at the top of the collection tank 3 via a tee.

[0038] It should be noted that:

[0039] 1. Currently, when receiving caprolactam, it is necessary to receive high-temperature caprolactam solutions one barrel at a time. At this time, caprolactam will combine with a large amount of oxygen, resulting in a large number of oxidation particles inside, which makes subsequent recycling difficult and causes partial damage. This device uses a fully enclosed pipeline for transportation and uses positive pressure nitrogen and high-temperature steam to remove oxygen, ensuring that caprolactam is in an oxygen-free environment during recovery. This prevents oxygen from merging into the caprolactam, effectively reducing the oxidation probability of caprolactam, and converting caprolactam into an aqueous solution for subsequent recovery processes. This greatly reduces losses, is pollution-free throughout the process, and ensures that the caprolactam does not come into contact with the external environment, resulting in high purity of recovered products.

[0040] When using this utility model, first close the valves on the feed pipe 12 and the discharge pipe 13 of the filter 1 to disconnect the filter 1 from production.

[0041] Then open the valves on steam pipe 4 and heating pipe 41 to deliver 0.5 bar of steam to exhaust pipe 11 and recovery pipe 14, so that the caprolactam in exhaust pipe 11 and recovery pipe 14 can be dissolved and circulated, ensuring that the pipeline is unobstructed.

[0042] At the same time, open the valve on the mixing pipe 21 and close the valve on the flushing pipe 2 to allow the demineralized water to be injected into the collection tank 3. Add about 500 kg of demineralized water into the collection tank 3 in advance.

[0043] After the exhaust pipe 11 and the recovery pipe 14 of filter 1 are heated, the valve on the recovery pipe 14 is slightly opened until liquid caprolactam flows out continuously and smoothly. At this time, the liquid caprolactam will flow into the collection tank 3 in sync with the water in the mixing pipe 21, and the caprolactam will be collected and diluted into an aqueous solution at the same time.

[0044] Then, slightly open the valve at the top of the exhaust pipe 11 until no caprolactam is sprayed out. Then, fully open the exhaust valve at the top of the exhaust pipe 11 and the valve of the recovery pipe 14. At the same time, open the valve of the nitrogen pipe 5. Open the valve of the nitrogen pipe 5 connecting the exhaust pipe 11 and the 6 bar nitrogen to an appropriate level. The pressure gauge 51 of the nitrogen pipe 5 should show about 1.5 bar. Pay attention to the outflow rate and nitrogen pressure change of the recovery pipe 14. If the caprolactam outflow is too small, open the valve of the nitrogen pipe 5 more. If the outflow is too large, close the valve of the nitrogen pipe 5 less.

[0045] After about 10 minutes of caprolactam flowing into the collection tank 3, a certain amount of caprolactam aqueous solution has been stored in the collection tank 3. The transfer pump 33 is connected to the bottom outlet of the collection tank 3 through the pipe joint 31, and then the transfer pump 33 is started to transport the caprolactam aqueous solution in the collection tank 3 to the extraction water storage tank. The concentration of the caprolactam aqueous solution in the collection tank 3 should be controlled at 20-30%. Therefore, it is necessary to inject an appropriate amount of demineralized water into the collection tank 3 through the mixing pipe 21.

[0046] When the pressure of nitrogen pipe 51 fluctuates significantly and the flow rate of caprolactam at the outlet of exhaust pipe 11 slows down, and a large amount of nitrogen is discharged, it indicates that the caprolactam in filter 1 is about to be exhausted. At this time, the valve on nitrogen pipe 5 should be adjusted to control the amount of nitrogen discharged until the caprolactam in exhaust pipe 11 is completely discharged, and then the valve on nitrogen pipe 5 should be closed.

[0047] Then open the valve on flushing pipe 2 and add demineralized water into filter 1. Use the demineralized water to flush the inside of filter 1 and rinse and soak the filter element and caprolactam on the inner wall of the tank.

[0048] After filling filter 1 with deionized water, close the valve on flushing pipe 2. Then you can begin the subsequent disassembly and cleaning of filter 1 to thoroughly clean the filter element and the inner wall of filter 3.

[0049] When the caprolactam aqueous solution in collection tank 3 is continuously transported to the bottom, a certain amount of demineralized water is injected into collection tank 3 through the mixing pipe 21 to facilitate the cleaning of collection tank 3 and subsequent discharge pipelines. In particular, the pipe joint 31, feed port 32 and transfer pump 33 need to be cleaned. Finally, the transfer pump 33 is turned off, the valve at the rear end of the transfer pump 33 is closed, and the pipe joint 31 is removed to complete the collection and transfer of caprolactam inside filter 1. Collection tank 3 can be connected to the recovery pipe 14 of another filter 1 for collection to complete the collection and preliminary cleaning of the other filter 1.

[0050] The front and rear ends of this device refer to the direction of liquid flow in the pipeline. The upstream of the liquid flow is the front end, and the downstream is the rear end. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the attached drawings. It is only for the convenience of describing this utility model and simplifying the description, and does not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this utility model.

[0051] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A filter recovery cleaning system for caprolactam, characterized by, The utility model relates to a kind of filter, flushing pipe, collection tank, steam pipe and nitrogen pipe comprising: The filter (1) is closed tank body, exhaust pipe (11) is provided on the top of the filter (1), a discharge pipe (13) is also provided on the top of the filter (1), and feed pipe (12) and recovery pipe (14) are also connected at the bottom of the filter (1);Valves are separately provided on the feed pipe (12), discharge pipe (13) and recovery pipe (14); The collection tank (3) is the storage tank of tank car, feed inlet (32) is provided on the top of the collection tank (3), the outlet of the recovery pipe (14) can be detachably inserted into the feed inlet (32), and a delivery pump (33) is also connected at the bottom of the collection tank (3), and the liquid outlet of the delivery pump (33) is sealingly connected with a storage tank; The flushing pipe (2), steam pipe (4) and nitrogen pipe (5) are all separate closed pipes, and the flushing pipe (2), steam pipe (4) and nitrogen pipe (5) are sealingly communicated with the exhaust pipe (11), the filter (1) is sealingly communicated with the desalted water pipeline through the flushing pipe (2), and the filter (1) is sealingly communicated with the water vapor pipeline through the steam pipe (4), The rear end of the steam pipe (4) is also connected with a heating pipe (41) through a tee joint, and the rear end of the heating pipe (41) is communicated with the recovery pipe (14); The rear end of the flushing pipe (2) is also connected with a deployment pipe (21), and the water outlet of the deployment pipe (21) is sealingly communicated with the feed inlet (32) in a detachable manner. Valves capable of being controlled independently are provided on the exhaust pipe (11), feed pipe (12), discharge pipe (13), recovery pipe (14), flushing pipe (2), deployment pipe (21), steam pipe (4), heating pipe (41) and nitrogen pipe (5).

2. A filter recovery cleaning system for caprolactam according to claim 1, wherein: Pressure gauges (51) are also provided on the nitrogen pipe (5), and pressure gauges (51) are also provided at the rear end of the delivery pump (33).

3. The filter system for purifying caprolactam according to claim 1, wherein: A pipe joint (31) is provided at the front end of the delivery pump (33), the pipe joint (31) is a quick connector of water pipe, and the delivery pump (33) is detachably connected with the storage tank of the collection tank (3) through the pipe joint (31); 4. The filter system for purifying caprolactam according to claim 1, wherein: Valves are provided at the front end of the pipe joint (31) and the rear end of the delivery pump (33). ​

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