A DMAC heated circulating cleaning system for spandex production

Abstract

This application provides a DMAC heating and circulating cleaning system for spandex production, comprising: a pipe or tank to be cleaned, the lower end of which is connected to the inlet of a shielded pump via a shielded pump inlet pipe; the outlet of the shielded pump is connected to the inlet of the inner tube of a jacketed pipe via a shielded pump outlet pipe; the outlet of the inner tube of the jacketed pipe is connected to the upper end of the pipe or tank to be cleaned, forming a closed-loop circulation path; the shielded pump inlet pipe is a T-junction structure, which is also connected to the DMAC supply pipeline; the shielded pump outlet pipe is a T-junction structure, with its first horizontal end connected to the lower end of the inner tube of the jacketed pipe, its second horizontal end connected to the waste liquid discharge pipeline, a pressure gauge installed at the vertical upper end, and its vertical lower end connected to the outlet of the shielded pump; valves are provided on the connecting pipes between the inner tube of the jacketed pipe and the pipe or tank to be cleaned, and on the connecting pipes between the outlet pipe of the shielded pump and the jacketed pipe. This application solves the problems of low efficiency and incomplete cleaning in traditional static heating cleaning by combining dynamic heating and circulating flushing.

Description

Technical Field

[0001] This application relates to the field of chemical equipment technology, specifically to a DMAC heating and circulating cleaning system for spandex production. Background Technology

[0002] In the spandex production process, storage tanks used to store prepolymers or DMAC, as well as pipelines transporting DMAC, inevitably develop crystal deposits after prolonged operation. These crystals are usually byproducts of incomplete reaction between the prepolymer and DMAC or degradation products of DMAC itself. Adhering to the inner walls of the tanks and pipelines, they not only affect the normal flow rate and purity of DMAC but may also lead to pipeline blockages and equipment wear. Therefore, cleaning and maintaining these storage tanks and pipelines is a crucial step in spandex production.

[0003] Traditional cleaning methods primarily rely on steam heating systems in the storage tanks and pipeline jackets. High-temperature steam is introduced into the jackets, using heat conduction to raise the temperature of DMAC (dimethylamine ether) and dissolve the crystalline deposits on the inner walls. However, this cleaning method requires intermittent operation and is mostly static heating, resulting in insufficient residence time of DMAC in the tanks and pipelines, leading to incomplete dissolution and inadequate cleaning. Furthermore, existing cleaning systems operate with independent heating, conveying, and cleaning functions, resulting in low system integration, inefficient coordination between different devices, and a high risk of solvent leakage or waste. Utility Model Content

[0004] The purpose of this invention is to provide a DMAC heating and circulating cleaning system for spandex production, which can solve the problems of low cleaning efficiency and solvent waste in the prior art.

[0005] This application is achieved through the following technical solution, specifically:

[0006] A DMAC heating and circulating cleaning system for spandex production, characterized in that it comprises: a pipe or tank to be cleaned, the lower end of which is connected to the inlet of a shielded pump via a shielded pump inlet pipe; the outlet of the shielded pump is connected to the inlet of the inner tube of a jacketed pipe via a shielded pump outlet pipe; the outlet of the inner tube of the jacketed pipe is connected to the upper end of the pipe or tank to be cleaned, forming a closed-loop circulation path; the outer tube of the jacketed pipe is used to introduce a heating medium; the shielded pump inlet pipe has a tee structure and is also connected to a DMAC supply pipeline; the shielded pump outlet pipe has a tee structure, the first horizontal end of which is connected to the lower end of the inner tube of the jacketed pipe, the second horizontal end of which is connected to a waste liquid discharge pipeline, a pressure gauge is installed at the vertical upper end, and the vertical lower end is connected to the outlet of the shielded pump; valves are provided on the connecting pipes between the inner tube of the jacketed pipe and the pipe or tank to be cleaned, and on the connecting pipes between the shielded pump outlet pipe and the jacketed pipe.

[0007] In this solution, a closed-loop circulation path is formed by connecting the pipe or tank to be cleaned, a canned motor pump, and a jacketed pipe in series. The pump's delivery capacity enables dynamic circulation of DMAC within the system. During circulation, the DMAC is continuously heated as it passes through the jacketed pipe, ensuring that the low-temperature DMAC is heated to the required temperature as it flows through, effectively enhancing its dissolving power. Simultaneously, the power provided by the canned motor pump allows the heated DMAC to continuously flush the inner wall of the pipe or tank, gradually dissolving and carrying away any attached crystalline deposits. This combination of dynamic heating and circulating flushing solves the problems of low efficiency and incomplete cleaning associated with traditional static heating cleaning, ensuring sufficient contact and dissolution of the DMAC and crystals.

[0008] As an improvement to the jacketed pipe in this application, the jacketed pipe is S-shaped; the upper part of the outer tube of the jacketed pipe is provided with a steam inlet, and the lower part is provided with a condensate outlet.

[0009] Furthermore, both the steam inlet and the condensate outlet are equipped with valves to control the entry and exit of steam and condensate.

[0010] As an improvement of this application, the outlet pipe of the shielded pump is connected to the inlet of the inner pipe of the jacketed pipe by a flexible hose, and the flexible hose is provided with flanges at both ends.

[0011] As an improvement to the canned pump outlet pipe of this application, the canned pump outlet pipe has an eccentric cross structure, and a waste liquid discharge valve is provided at the second horizontal end of the canned pump outlet pipe where it connects to the waste liquid discharge pipeline.

[0012] As an improvement to the canned motor pump inlet pipe in this application, the canned motor pump inlet pipe has a T-shaped tee structure, with its two horizontal ends connected to the lower end of the pipe or tank to be cleaned and the DMAC supply pipeline, respectively, and its vertical end connected to the inlet of the canned motor pump. A DMAC inlet valve is provided between the canned motor pump inlet pipe and the DMAC supply pipeline.

[0013] The beneficial effects of this application are as follows:

[0014] This application's solution establishes a closed-loop circulation path by connecting the pipe or tank to be cleaned, a canned motor pump, and a jacketed pipe in series. Utilizing the pump's delivery capacity, dynamic circulation of DMAC is achieved within the system. During circulation, the DMAC is continuously heated as it passes through the jacketed pipe, ensuring that the low-temperature DMAC is heated to the required temperature as it flows through the jacket, effectively enhancing its dissolving power. Simultaneously, the power provided by the canned motor pump allows the heated DMAC to continuously flush the inner wall of the pipe or tank, gradually dissolving and carrying away any attached crystalline deposits. This combination of dynamic heating and circulating flushing solves the problems of low efficiency and incomplete cleaning associated with traditional static heating cleaning, ensuring sufficient contact and dissolution of DMAC and the crystals.

[0015] In addition to the technical problems solved by this utility model, the technical features constituting the technical solution, and the advantages brought about by the technical features of these technical solutions as described above, other technical problems that this utility model can solve, other technical features contained in the technical solution, and the advantages brought about by these technical features will be further explained in detail with reference to the accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a DMAC heating and circulating cleaning system for spandex production in an embodiment of this application.

[0017] Explanation of reference numerals in the attached figures:

[0018] 1. Pipe or tank to be cleaned; 2. Shielded pump inlet pipe; 3. Shielded pump; 4. Shielded pump outlet pipe; 5. Jacketed pipe; 51. Inlet of inner tube of jacketed pipe; 52. Outlet of inner tube of jacketed pipe; 6. Pressure gauge; 7. Valve; 8. Hoses; 21. DMAC inlet valve; 41. Waste liquid discharge valve; 53. Steam inlet; 54. Condensate outlet. Detailed Implementation

[0019] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of this application, and are therefore merely examples and should not be used to limit the scope of protection of this application. Furthermore, the technical features involved in the various embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0020] In view of the problems existing in the background technology or products, Figure 1 A schematic diagram of a DMAC heating and circulating cleaning system for spandex production, as shown in an embodiment of this application, is illustrated. Figure 1As shown in the figure, this application provides a DMAC heating and circulating cleaning system for spandex production, including: a pipe or tank 1 to be cleaned, the lower end of which is connected to the inlet of a shielded pump 3 via a shielded pump inlet pipe 2; the outlet of the shielded pump 3 is connected to the inner tube inlet 51 of a jacketed pipe 5 via a shielded pump outlet pipe 4; the inner tube outlet 52 of the jacketed pipe 5 is connected to the upper end of the pipe or tank 1 to be cleaned, forming a closed-loop circulation path; the outer tube of the jacketed pipe 5 is used to introduce a heating medium; the shielded pump inlet pipe 2 is a three-way structure, and the shielded pump inlet pipe 2 is also connected to a DMAC supply pipeline; the shielded pump outlet pipe 4 is a four-way structure, the first horizontal end of which is connected to the lower end of the inner tube of the jacketed pipe 5, the second horizontal end of which is connected to a waste liquid discharge pipeline, a pressure gauge 6 is installed at the vertical upper end, and the vertical lower end is connected to the outlet of the shielded pump 3;

[0021] Valves 7 are provided on the inner pipe of the jacketed pipe 5 and the connecting pipe to be cleaned or the tank 1, as well as on the connecting pipe of the shielded pump outlet pipe 4 and the jacketed pipe 5.

[0022] Specifically, the canned motor pump 3 serves as the system's power source, ensuring the continuous and stable flow of DMAC within the closed-loop circulation path, thereby achieving continuous flushing of the crystalline deposits. The inner tube of the jacketed pipe 5 is used for DMAC flow, while the outer tube is used for introducing the heating medium. As DMAC passes through the inner tube of the jacketed pipe 5, it exchanges heat with the heating medium in the outer tube, causing the low-temperature DMAC to be heated upon entering the jacketed pipe 5. The heated DMAC is then transported back to the pipeline or tank 1 to be cleaned, thus achieving dynamic heating and circulation of DMAC. A DMAC supply line (not shown in the figure) is used to replenish the system with new DMAC.

[0023] The canned motor pump outlet pipe 4 has a four-way structure. Its first horizontal end connects to the lower end of the inner tube of the jacketed pipe 5, ensuring that DMAC can smoothly enter the jacketed pipe 5 for heating after being pumped out from the canned motor pump 3. The second horizontal end connects to the waste liquid discharge pipeline, used to discharge waste liquid containing dissolved crystals after cleaning, or to discharge part of the waste liquid during cleaning as needed to replace fresh DMAC. A pressure gauge 6 is installed at the vertical upper end for real-time monitoring of the pressure in the system pipeline, so that operators can understand the system operating status and ensure the safety and stability of the cleaning process. The vertical lower end connects to the outlet of the canned motor pump 3, realizing the delivery of DMAC from the canned motor pump 3 to the jacketed pipe 5.

[0024] Valve 7 is used to achieve precise control of the DMAC flow direction, such as closing the waste liquid discharge valve before cleaning, opening the waste liquid discharge valve after cleaning, and ensuring the smooth flow of the closed loop during normal circulation cleaning. Valve 7 is preferably a DN25 ball valve.

[0025] In one implementation, the jacketed tube 5 is S-shaped; the upper part of the outer tube of the jacketed tube 5 is provided with a steam inlet 53, and the lower part is provided with a condensate outlet 54.

[0026] Specifically, the S-shaped bend structure helps increase the heat exchange area and extend the residence time of the DMAC within the jacket tube, thereby improving heating efficiency. Steam inlet 53 is used to introduce high-temperature steam as the heating medium; condensate outlet 54 is used to discharge condensate after steam condensation, ensuring smooth steam flow and effective heat exchange within the jacket. Preferably, both steam inlet 53 and condensate outlet 54 are equipped with valves to control the entry and exit of steam and condensate. Both steam inlet 53 and condensate outlet 54 are equipped with DN25 flange interfaces and are respectively connected to ball valves. The inner and outer tube materials of the jacket tube 5 are preferably stainless steel.

[0027] Optionally, the inner diameter of the jacketed tube 5 is 25mm, the outer diameter is 40mm, the length is 500mm, and the height is 400mm.

[0028] In one implementation, the outlet pipe 4 of the shielded pump is connected to the inlet pipe of the inner tube of the jacketed pipe 5 via a flexible hose 8, with flanges at both ends of the flexible hose 8. The flexible hose 8 connection has a certain degree of flexibility, which facilitates installation and adjustment and can adapt to different installation spaces and position requirements. The flange connection ensures the sealing and stability of the connection and prevents DMAC leakage.

[0029] In one implementation, the shielded pump outlet pipe 4 has an eccentric cross structure, and a waste liquid discharge valve 41 is provided at the second horizontal end of the shielded pump outlet pipe 4 where it connects to the waste liquid discharge pipeline.

[0030] Specifically, the waste liquid discharge valve 41 is used to control the discharge of waste liquid. After the pipeline or tank is cleaned, the waste liquid discharge valve 41 is opened and the shielded pump 3 is turned on, so that the DMAC in the pipeline or tank can be transferred to the waste liquid tank.

[0031] In one implementation, the shielded pump inlet pipe 2 is a T-shaped tee structure, with its two horizontal ends connected to the lower end of the pipe or tank 1 to be cleaned and the DMAC supply pipeline, respectively, and its vertical end connected to the inlet of the shielded pump 3. A DMAC inlet valve 21 is provided between the shielded pump inlet pipe 2 and the DMAC supply pipeline.

[0032] Specifically, during the circulating cleaning process, the DMAC inlet valve 21 is typically kept closed to isolate the DMAC supply line from the main circulation path, preventing DMAC from flowing back to the supply source and preventing air or impurities in the supply line from entering the circulation system, thus ensuring the stability of the circulation process and the purity of the medium. When DMAC needs to be injected into the system (e.g., for initial filling or replenishment), the operator can precisely open the DMAC inlet valve 21 to control the injection volume and rate. This avoids the risk of rapid DMAC influx or overflow due to lack of valve control, ensuring operational safety.

[0033] The working process of the heating and circulating cleaning system in this application is as follows:

[0034] 1. Connect the steam inlet flange to the steam inlet 53 flange of the upper outer pipe of the jacketed pipe 5, and connect the condensate pipe to the condensate outlet 54 flange of the lower outer pipe of the jacketed pipe 5; connect the outlet 52 of the inner pipe of the jacketed pipe to the upper end of the pipe or tank 1 to be cleaned through a pipe with valve 7; connect the inlet 51 of the inner pipe of the jacketed pipe to the outlet of the shielded pump 3 through the outlet pipe 4 of the shielded pump with valve 7; connect the left lateral end of the inlet pipe 2 of the shielded pump to the lower end of the pipe or tank 1 to be cleaned.

[0035] 2. Open the DMAC inlet valve 21, steam inlet ball valve 53, condensate outlet ball valve 54, and valves 7 at the outlet and inlet ends of the pipeline or tank to be cleaned in sequence;

[0036] 3. Slowly open the exhaust port on top of the shielded pump 3 until all the air is expelled, then close it;

[0037] 4. Close the DMAC inlet valve 21, start the power supply to the canned motor pump 3, and observe the pressure gauge 6 at the vertical end of the canned motor pump outlet pipe 4. When the reading stabilizes at 0.2MPa, confirm that the DMAC circulation is normal.

[0038] 5. The temperature of the inner tube DMAC is increased by steam heating the outer tube of the jacketed tube 5. If the temperature is abnormal, check the opening of the steam inlet 53 and the condensate outlet 54 valves.

[0039] 6. The closed-loop cycle runs continuously for more than 6 hours, and the dynamically heated DMAC is driven by the shielded pump 3 to flush the inner wall of the pipe or tank 1 to be cleaned and dissolve the crystals.

[0040] 7. After turning off the power to the shielded pump 3, turn off the steam inlet valve 53, the condensate outlet valve 54 and the inlet valve 7 of the pipe or tank to be cleaned in sequence. Then, open the waste liquid discharge valve 41 and discharge the DMAC waste liquid through the waste liquid discharge end of the shielded pump outlet pipe 4.

[0041] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "set", "equipped with", "connected", and "installed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A DMAC heating and circulating cleaning system for spandex production, characterized in that, include: The lower end of the pipe or tank (1) to be cleaned is connected to the inlet of the shielded pump (3) through the inlet pipe (2) of the shielded pump; the outlet of the shielded pump (3) is connected to the inlet (51) of the inner tube of the jacketed pipe (5) through the outlet pipe (4); the outlet (52) of the inner tube of the jacketed pipe (5) is connected to the upper end of the pipe or tank (1) to be cleaned, forming a closed loop circulation path; the outer tube of the jacketed pipe (5) is used to introduce the heating medium; the inlet pipe (2) of the shielded pump is a three-way structure, and the inlet pipe (2) of the shielded pump is also connected to the DMAC supply pipeline; the outlet pipe (4) of the shielded pump is a four-way structure, the first horizontal end of which is connected to the lower end of the inner tube of the jacketed pipe (5), the second horizontal end of which is connected to the waste liquid discharge pipeline, the pressure gauge (6) is installed at the vertical upper end, and the vertical lower end is connected to the outlet of the shielded pump (3); Valves (7) are provided on the inner pipe of the jacketed pipe (5) and the connecting pipe to be cleaned or the tank (1), and on the connecting pipe of the shielded pump outlet pipe (4) and the jacketed pipe (5).

2. The DMAC heating and circulating cleaning system as described in claim 1, characterized in that, The jacketed pipe (5) is S-shaped; the upper part of the outer pipe of the jacketed pipe (5) is provided with a steam inlet (53) and the lower part is provided with a condensate outlet (54).

3. The DMAC heating and circulating cleaning system as described in claim 2, characterized in that, Both the steam inlet (53) and the condensate outlet (54) are equipped with valves to control the entry and exit of steam and condensate.

4. The DMAC heating and circulating cleaning system as described in claim 1, characterized in that, The outlet pipe (4) of the shielded pump is connected to the inlet of the inner pipe of the jacketed pipe (5) by a flexible hose (8), and the flexible hose (8) has flanges at both ends.

5. The DMAC heating and circulating cleaning system as described in claim 1, characterized in that, The outlet pipe (4) of the shielded pump has an eccentric cross structure, and a waste liquid discharge valve (41) is provided at the second horizontal end of the outlet pipe (4) where it is connected to the waste liquid discharge pipeline.

6. The DMAC heating and circulating cleaning system as described in claim 1, characterized in that, The inlet pipe (2) of the shielded pump is a T-shaped tee structure. Its two horizontal ends are connected to the lower end of the pipe or tank (1) to be cleaned and the DMAC supply pipeline, respectively. Its vertical end is connected to the inlet of the shielded pump (3). A DMAC inlet valve (21) is provided between the inlet pipe (2) of the shielded pump and the DMAC supply pipeline.

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