Filter in extraction tower and filtering system in extraction tower for polycaprolactam production using same

Abstract

The utility model belongs to the technical field of polycaprolactam polymerization production, and particularly relates to a filter in an extraction tower and a filter system in the extraction tower used for polycaprolactam production and applying the filter. The filter in the extraction tower comprises a tubular filter screen, the tubular filter screen comprises a non-porous pipe and a filter outer pipe which are coaxially arranged inside and outside, filter holes are densely distributed in the pipe wall of the filter outer pipe, the pipe wall of the non-porous pipe is smooth and non-porous, one end of the filter outer pipe is gradually reduced to form a necking opening, and the end part of the non-porous pipe is fixedly connected with the necking opening of the filter outer pipe; and the height of the non-porous pipe is lower than that of the filtering outer pipe. The extraction tower inner filtering system comprises an extraction tower, an extraction tower inner filter is mounted on a filtering mounting pipeline of the extraction tower, and a necking opening of a filtering outer pipe is communicated with an overflow pipeline. According to the utility model, the siphonic effect is effectively reduced, the blockage of the filter is reduced, the frequent cleaning caused by the blockage of the filter is avoided, the shutdown time of an extraction procedure is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This utility model belongs to the field of polycaprolactam polymerization production technology, and particularly relates to an extraction tower filter and an extraction tower filtration system using the same for polycaprolactam production. Background Technology

[0002] In the polycaprolactam polymerization production line, nylon 6 chips after pelleting fall directly into the extraction system. Extraction is carried out at a high temperature with high-concentration extraction water. Inside the extraction tower, monomers and oligomers in the chips are dissolved by high-temperature demineralized water and extracted from the chips. The chips flow counter-currently from top to bottom, while the high-temperature demineralized water flows counter-currently from bottom to top, eluting the chips. Water containing a certain concentration of monomers overflows from the extraction tower to the high-level extraction water tank, circulating in the extraction water system. When the material level in the extraction tower is high or fluctuates, chips and water enter the overflow pipe together, causing blockage in the extraction water circulation system. Installing an in-extraction tower filter can effectively prevent chips from entering the overflow pipe. Existing in-extraction tower filters typically use a mesh structure. When installed on the extraction tower, the bottom pores are the first to function. Due to the significant siphon effect generated when the extraction water overflows, the chips are tightly adsorbed onto the outer wall of the filter, causing the bottom pores to clog first, and then gradually clogging the entire filter, reducing its effectiveness. To ensure stable operation of the extraction system, frequent disassembly and cleaning of the in-extraction tower filter is necessary.

[0003] The existing solution involves shutting down the extraction process and disassembling the filter for cleaning. However, this approach not only disrupts normal production and increases labor intensity, but it is also ineffective in handling severe blockages, potentially leading to prolonged shutdowns of the production unit and seriously affecting product quality.

[0004] The existing technology has the following drawbacks:

[0005] 1. When the existing extraction tower filter is installed, the bottom holes are the first to be activated. Due to the siphon effect, the slices are adsorbed onto the outer wall of the filter, causing the bottom holes to become clogged first, and then gradually clogging the entire filter, which reduces the filter's effectiveness and requires frequent disassembly and cleaning.

[0006] 2. The existing technology involves shutting down the extraction process and disassembling the filter for cleaning. This not only affects normal production and increases labor, but is also ineffective in dealing with severe blockages, which may lead to prolonged shutdown of the production unit and seriously affect product quality.

[0007] 3. Existing technology cannot adjust the setting position and parameters of compressed air pipelines and solenoid valves according to the actual accumulation of chips and oligomer monomers, and cannot effectively clean the filter;

[0008] 4. Existing technologies cannot optimize the process water inlet and outlet pipelines to improve their flow rate and uniformity, ensure effective circulation and uniform distribution of process water, and cannot effectively prevent filter clogging.

[0009] To address the aforementioned issues, a novel filter structure design is needed that can effectively reduce the siphon effect, decrease the frequency of filter clogging, thereby improving production efficiency, reducing labor intensity, and ensuring product quality. Utility Model Content

[0010] In order to solve the problem of easy clogging of the filter in the extraction tower in the prior art, which requires frequent disassembly and cleaning, this utility model provides an extraction tower filter and an extraction tower filtration system using the same for the production of polycaprolactam.

[0011] The present invention adopts the following technical solution:

[0012] An extraction tower internal filter includes a tubular filter screen, which comprises a non-porous tube and a filter outer tube arranged coaxially inside and out. The wall of the filter outer tube is densely covered with filter pores, and the wall of the non-porous tube is smooth and non-porous. One end of the filter outer tube gradually narrows to form a constriction. The end of the non-porous tube is fixedly connected to the constriction of the filter outer tube, and the height of the non-porous tube is lower than the height of the filter outer tube.

[0013] In the above technical solution, the non-porous tube and the outer filter tube are connected by welding at the constriction. The height of the non-porous tube is not higher than the height of the filter holes of the outer filter tube. More preferably, the height of the non-porous tube is lower than the height of the filter holes of the outer filter tube.

[0014] In the above technical solution, the non-porous tube is a stainless steel tube.

[0015] In the above technical solution, a cap is provided at the end of the filter outer tube away from the constriction.

[0016] In the above technical solution, multiple fixing holes are formed on the end cap along its circumferential direction.

[0017] The second objective of this invention is to provide an in-extraction tower filtration system for polycaprolactam production, comprising an extraction tower, wherein a slice feed pipe and a filter installation pipe are provided at the top of the extraction tower, an overflow pipe is provided inside the extraction tower, and the filter installation pipe is equipped with the aforementioned in-extraction tower filter, and the constricted end of the filter outer tube is connected to the overflow pipe.

[0018] In the above technical solution, the central axis of the filter installation pipe coincides with the central axis of the overflow pipe, and the constricted end of the filter outer tube is inserted into the overflow pipe of the extraction tower and connected to the overflow pipe.

[0019] In the above technical solution, the minimum outer diameter of the constricted opening of the filter outer tube is smaller than the inner diameter of the overflow pipe, and the maximum outer diameter is larger than the inner diameter of the overflow pipe.

[0020] In the above technical solution, the top of the filter installation pipe is provided with an installation flange, and the end cap is fixedly connected to the installation flange at the top of the extraction tower through a fixing hole.

[0021] In the above technical solution, the extraction tower is also equipped with a sight glass for observing the filter.

[0022] Combining all the above technical solutions, the advantages and positive effects of this utility model are as follows:

[0023] 1. This utility model effectively reduces the siphon effect, allowing all the pores of the filter to work together, thereby significantly reducing filter clogging, avoiding frequent cleaning due to filter blockage, reducing downtime in the extraction process, and improving production efficiency.

[0024] 2. This utility model reduces the labor intensity of workers and lowers the input of labor costs.

[0025] 3. In this invention, the stable extraction process ensures the effective extraction of unreacted monomers from polycaprolactam chips, improves the quality of the final product, and reduces waste generated due to production interruptions, resulting in significant economic and environmental benefits.

[0026] 4. In this utility model, the non-porous tube is made of corrosion-resistant and high-strength materials, such as stainless steel, to ensure long-term stable operation in the harsh environment inside the extraction tower, avoid equipment failure due to material problems, extend the service life of the equipment, and reduce the maintenance cost of the equipment. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure;

[0028] Figure 1 This is a schematic diagram of the structure of the improved internal filter of the extraction tower for the production of polycaprolactam according to this utility model;

[0029] Figure 2 This is a cross-sectional view of the improved internal filter of the extraction tower for the production of polycaprolactam according to this utility model;

[0030] Figure 3 This is a schematic diagram of the assembly structure of the improved internal filter of the extraction tower for the production of polycaprolactam according to this utility model.

[0031] In the diagram: 1-End cap; 2-Fixing hole; 3-Tubular filter screen; 4-Non-porous tube; 5-Narrowing; 6-Filter hole; 7-Mounting flange; 8-Slice feed pipe; 9-Extraction tower; 10-Sight glass; 11-Overflow pipe. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solution of this utility model, the following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the technical solution of an improved internal filter for the production of polycaprolactam. Example 1

[0033] An extraction tower internal filter includes a tubular filter screen, comprising a non-porous tube and an outer filter tube arranged coaxially inside and outside the filter screen. The outer filter tube has a wall densely covered with filter holes, and the wall of the non-porous tube is smooth and non-porous. One end of the outer filter tube is provided with a cap, and the other end gradually narrows to form a constriction for communication with the overflow pipe inside the extraction tower. A non-porous tube is welded inside the outer filter tube, and the non-porous tube is connected to the lower constriction of the outer filter tube by welding, with the height not exceeding the height of the filter holes in the outer filter tube.

[0034] In this embodiment, as Figure 1 ~ As shown in Figure 3, one end of the outer tube of the tubular filter screen 3 is provided with a cap 1, and the other end forms a gradually narrowing neck 5. The neck 5 is inserted into the overflow pipe 11 in the extraction tower 9 and connected. The outer tube is densely covered with filter holes 6. A non-porous tube 4 is welded inside the outer tube. The non-porous tube 4 is connected to the lower neck 5 of the outer tube by welding, and its height is not higher than the height of the filter holes 6 of the outer tube. Example 2

[0035] An in-extraction tower filtration system for polycaprolactam production includes an extraction tower 9, with a slice feed pipe 8 and a filter installation pipe at the top of the extraction tower 9. An overflow pipe 11 is provided inside the extraction tower 9, and the filter installation pipe is equipped with the aforementioned in-extraction tower filter. The constricted end of the filter outer tube is connected to the overflow pipe 11.

[0036] Furthermore, in this embodiment, the filter outer tube is made of stainless steel, approximately 90cm long and 20cm in diameter, with 60-mesh filter holes evenly distributed. Its structure effectively prevents the slices from entering the overflow pipe 11.

[0037] Furthermore, in this embodiment, the end cap 1 is made of stainless steel with a diameter of 50cm. It is fixedly connected to the top flange 7 of the extraction tower, and its outer circumference forms multiple evenly distributed fixing holes 2 for connecting with the flange holes at the top of the extraction tower. In this embodiment, there are eight such holes.

[0038] Furthermore, in this embodiment, the minimum outer diameter of the constriction 5 is smaller than the inner diameter of the overflow pipe 11, and its maximum outer diameter is larger than the inner diameter of the overflow pipe 11. The minimum outer diameter of the constriction 5 (port portion) is 14cm, and the diameter change point of 19cm matches the inner diameter of the overflow pipe 11 of 19cm.

[0039] Furthermore, in this embodiment, the non-porous tube is made of stainless steel with a diameter of 16cm and is connected to the constriction 5 by welding.

[0040] Furthermore, in this embodiment, the tubular filter screen 3 can also be observed through the sight glass 10 provided on the extraction tower 9.

[0041] This embodiment presents an internal filtration system for the extraction tower in polycaprolactam production. This system effectively prevents the entry of chips into the overflow pipe, thus preventing blockage of the extraction water circulation system. An additional non-porous tube is added to the existing internal filter and welded inside the outer filter tube. Existing internal filters in extraction towers frequently clog due to siphon effects during production, severely impacting normal production and requiring frequent shutdowns for cleaning. This also affects the extraction efficiency of the tower, leading to fluctuations in product quality. The improved system completely eliminates the clogging problem caused by the siphon effect. Compared to conventional filters, this invention reduces the siphon effect, effectively minimizing filter clogging, avoiding frequent cleaning due to filter blockage, reducing labor, and improving both economic efficiency and safety. Furthermore, it saves significant downtime, increases production capacity, and prevents product quality fluctuations.

[0042] The above description is merely a preferred embodiment of this utility model. It should be understood that the described embodiments are only a part of the embodiments of this utility model, not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. This utility model is not limited to the forms disclosed herein and should not be considered as excluding other embodiments, but can be used in various other combinations, modifications, and environments. Modifications and changes made by those skilled in the art that do not depart from the spirit and scope of this utility model should be within the protection scope of the appended claims.

Claims

1. An in-extraction column filter, characterized by: The filter comprises a tubular filter screen, which comprises a non-porous tube and a filter outer tube arranged coaxially inside and outside, the filter outer tube is densely provided with filter holes on the tube wall, the tube wall of the non-porous tube is smooth and non-porous, one end of the filter outer tube is gradually reduced in diameter to form a neck, the end of the non-porous tube is fixedly connected with the neck of the filter outer tube, and the height of the non-porous tube is lower than that of the filter outer tube.

2. An in-tower filter according to claim 1, characterized in that: The non-porous tube and the neck of the filter outer tube are connected by welding, and the height of the non-porous tube is not higher than the height of the filter holes of the filter outer tube.

3. An in-tower filter according to claim 1, wherein: The non-porous tube is a stainless steel tube.

4. An in-tower filter according to claim 1, wherein: The end of the filter outer tube away from the neck is provided with an end cover.

5. An in-tower filter according to claim 4, wherein: A plurality of fixing holes are formed on the end cover along the circumferential direction thereof.

6. An extraction column internal filtration system for polycaprolactam production, comprising an extraction column, a slice feed pipe and a filter installation pipe are arranged at the top of the extraction column, an overflow pipe is arranged in the interior of the extraction column, characterized in that: The filter installation pipe is provided with the filter in the extraction tower as claimed in any one of claims 1-5, and the neck of the filter outer tube is communicated with the overflow pipe.

7. A filter system for use in an extraction column for polycaprolactam production according to claim 6, characterized in that: The central axis of the filter installation pipe and the central axis of the overflow pipe coincide with each other, the neck of the filter outer tube is inserted into the overflow pipe of the extraction tower and connected with the overflow pipe.

8. A filter system for use in an extraction column for polycaprolactam production according to claim 6, characterized in that: The minimum outer diameter of the neck of the filter outer tube is smaller than the inner diameter of the overflow pipe, and the maximum outer diameter is greater than the inner diameter of the overflow pipe.

9. A filter system for use in an extraction column for polycaprolactam production according to claim 6, characterized in that: The top of the filter installation pipe is provided with a mounting flange, and the end cover is fixedly connected with the mounting flange at the top of the extraction tower through the fixing holes.

10. The filter system for use in an extraction column for polycaprolactam production according to claim 6, characterized in that: The extraction tower is further provided with a sight glass for observing the filter.

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