Phase separation and recovery device for polyacrylonitrile spinning dimethyl sulfoxide-containing wastewater

Abstract

The invention belongs to the technical field of waste liquid resourceful treatment, and particularly relates to a phase separation and recovery device for polyacrylonitrile spinning dimethyl sulfoxide-containing waste water. Comprising a transpiration multi-section type combined pipeline which comprises a continuous S-shaped flow channel formed by alternately connecting vertical sections and horizontal sections; a heat supply system; and each condensation recovery device is connected with the corresponding horizontal section. By adopting the S-shaped transpiration multi-section combined pipeline, transpiration, separation and condensation are integrated, the space utilization rate is high, and the process is continuous. A pneumatic device is arranged in the pipeline, so that gas flow conveying in a specific direction is realized, and the conveying flow of a gas-fog mixture can be adjusted; through the multi-stage gradient heating combination including external heating and inert gas mixing heating, the heating efficiency is high, and the phase separation process can be more accurately controlled; the design of a condensation recovery device is matched, so that the separation efficiency of DMSO and water and the product purity are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of waste liquid resource utilization technology, and particularly relates to a phase separation and recovery device for dimethyl sulfoxide wastewater from polyacrylonitrile spinning. Background Technology

[0002] In the wet spinning or dry-jet wet spinning process of polyacrylonitrile (PAN) precursor fibers, dimethyl sulfoxide (DMSO) is widely used as a polymer solvent due to its excellent solubility and thermal stability. During the preparation of spinning solutions, spinning formation, and subsequent processes such as coagulation, washing, and drawing, a large amount of wastewater mixtures containing varying concentrations of DMSO are generated. This wastewater has a complex composition, high COD, and is difficult to biodegrade; direct discharge would cause serious pollution to water bodies and the atmosphere. Furthermore, DMSO itself is a high-value solvent, and its direct disposal also results in significant economic losses and resource waste.

[0003] Existing methods for treating DMSO-containing wastewater mainly include oxidation, membrane separation, and distillation. While oxidation can degrade pollutants, it cannot recover DMSO and is prone to secondary pollution. Membrane separation is limited by the membrane material's tolerance to DMSO and membrane fouling issues, making it difficult to treat high-concentration wastewater, and the purity of the produced water often fails to meet reuse requirements. Distillation is currently the most widely used method in industry, utilizing the boiling point difference between DMSO and water for separation and recovery. However, due to DMSO's high boiling point (189℃) and strong hydrogen bonding with water molecules, conventional distillation processes require high heat input, resulting in significant energy consumption. Furthermore, under high-temperature operating conditions, DMSO poses a risk of thermal decomposition, potentially generating odorous and toxic byproducts such as dimethyl sulfide, increasing the difficulty of subsequent treatment and environmental risks. Multistage distillation tower equipment also suffers from high investment costs, complex operation and maintenance, and large footprint.

[0004] Therefore, in response to the urgent need for DMSO-containing wastewater treatment and resource recovery in the PAN spinning industry, it is imperative to develop a new, efficient, energy-saving treatment device that can recover solvents, in order to overcome the shortcomings of existing technologies and promote the green, low-carbon, and circular development of the industry. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a phase separation and recovery device for polyacrylonitrile spinning wastewater containing dimethyl sulfoxide, achieving efficient phase separation during the aerosol conveying process and recovering dimethyl sulfoxide.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows: This invention provides a phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning, comprising: Evaporation multi-section combined pipeline, which includes a continuous S-shaped flow channel composed of alternating vertical and horizontal sections; The heating system is arranged in the vertical section of the multi-segment combined pipeline for gradient heating of the aerosol mixture in the pipeline. A condensation recovery system includes multiple condensation recovery devices adapted to the number of horizontal sections, each of the condensation recovery devices being connected to the corresponding horizontal section via a porous gas baffle. The multi-segment combined evaporation pipeline is equipped with a pneumatic device inside to drive the aerosol mixture to flow from bottom to top.

[0007] Optionally, the pneumatic device includes a plurality of built-in fan assemblies arranged on the inner wall of the multi-segment combined evaporation pipeline.

[0008] Optionally, the condensation recovery device is a tank-tower structure with multiple layers of aerosol condensation baffles inside, and the aerosol condensation baffles are connected to liquid outlet pipelines.

[0009] Optionally, the condensate recovery device located on the downstream horizontal section is connected to the DMSO collection tank via a liquid outlet pipeline, while the condensate recovery devices located on other horizontal sections are connected to the water storage tank via liquid outlet pipelines.

[0010] Optionally, the evaporative multi-segment combined pipeline includes at least three vertical segments and at least three horizontal segments, and the heating system includes at least three stages of heating devices arranged sequentially along the direction of vapor flow, with the three stages of heating devices respectively arranged on different vertical segments.

[0011] Optionally, the at least three-stage heating device includes a first-stage heating device, a second-stage heating device, and a third-stage heating device arranged sequentially along the direction of aerosol flow; The first-stage heating device is used to heat the DMSO wastewater mixture in the pipeline to 110-130°C to form an initial aerosol mixture; The second-stage heating device is used to heat the aerosol mixture to 140-160°C, and the third-stage heating device is used to heat the aerosol mixture to 180-200°C.

[0012] Optionally, the first-stage heating device is an external linear heating element that is wound around the outer wall of the initial vertical section of the evaporation multi-segment combined pipeline; And / or, the second-stage heating device and the third-stage heating device are high-temperature inert gas mixed-in heating devices.

[0013] Optionally, the high-temperature inert gas mixing heating device includes an inert gas source pipeline and a gas injection pipe. The outlet end of the inert gas source pipeline extends into the corresponding vertical section and is connected to the gas injection pipe. The injection direction of the gas injection pipe is the same as the gas mist flow direction.

[0014] Optionally, the gas injection pipe has an L-shaped structure, and the second-stage heating device and the third-stage heating device are each equipped with 3-5 sets of gas injection pipes.

[0015] Optionally, the evaporation multi-segment combined pipeline includes three vertical segments and three horizontal segments.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: This invention employs an S-shaped, multi-segment combined evaporation pipeline, integrating evaporation, separation, and condensation into a single unit, resulting in high space utilization and a continuous process. A pneumatic device is installed within the pipeline to achieve directional gas flow and adjust the flow rate of the aerosol mixture. Furthermore, a multi-stage gradient heating combination, including external heating and inert gas mixing heating, not only ensures high heating efficiency but also precisely controls the phase separation process. Combined with the design of a condensation recovery device, this effectively improves the separation efficiency and product purity of DMSO and water, enabling the recovery and reuse of DMSO from wastewater. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, 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.

[0018] Figure 1 This is a schematic diagram of the phase separation and recovery device for dimethyl sulfoxide wastewater from polyacrylonitrile spinning according to Embodiment 1 of the present invention. Explanation of reference numerals in the attached figures: 1. Multi-stage combined evaporation pipeline; 2. Pneumatic device; 3. Porous gas baffle; 4. First-stage heating device; 5. Second-stage heating device; 6. Third-stage heating device; 7. Gas injection pipe; 8. Condensation recovery device; 9. Aerosol condensation baffle; 10. Water storage tank; 11. DMSO collection box. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0022] Example 1

[0023] like Figure 1 As shown, a phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning includes: a multi-segment evaporation combined pipeline 1, which includes a continuous S-shaped flow channel composed of alternating vertical and horizontal sections; a heating system arranged in the vertical section of the multi-segment evaporation combined pipeline 1 for gradient heating of the aerosol mixture in the pipeline; and a condensation recovery system, which includes multiple condensation recovery devices 7 adapted to the number of horizontal sections, each condensation recovery device 7 being connected to the corresponding horizontal section through a porous gas baffle 3; wherein, the multi-segment evaporation combined pipeline 1 is internally equipped with a pneumatic device 2 for driving the aerosol mixture to flow from bottom to top.

[0024] This invention employs an S-shaped multi-segment combined pipeline, integrating evaporation, separation, and condensation into one, resulting in high space utilization and a continuous process. During operation, the waste liquid is heated step by step in the pipeline, and then flows upward along the pipeline under the action of the pneumatic device 2. When passing through the horizontal section, water vapor is first separated and condensed, and then DMSO vapor is condensed and recovered in the final stage, achieving effective separation and resource utilization of solvent and wastewater.

[0025] Example 2

[0026] The difference between this embodiment and embodiment 1 is that the pneumatic device 2 includes multiple built-in fan groups arranged on the inner wall of the multi-segment combined evaporation pipeline 1, and the built-in fan groups are connected to the inner wall of the pipeline through flanges.

[0027] The multi-stage evaporative combined pipeline 1 includes at least three vertical sections and at least three horizontal sections. The heating system includes at least three stages of heating devices arranged sequentially along the direction of vapor flow, with each stage located on a different vertical section. In this embodiment, the multi-stage evaporative combined pipeline 1 has three vertical and three horizontal sections. Correspondingly, the heating devices include three stages: a first-stage heating device 4, a second-stage heating device 5, and a third-stage heating device 6, arranged sequentially along the direction of vapor flow on different vertical sections.

[0028] The first-stage heating device 4 is an external linear heating element, such as carbon fiber heating wire or metal heating wire. In this embodiment, carbon fiber heating wire is used, which is wound around the outer wall of the initial vertical section of the evaporation multi-segment combined pipeline 1 to heat the DMSO wastewater mixture in the pipeline to 110-130°C to form an initial aerosol mixture (in this embodiment, it is controlled to heat the aerosol mixture to 110°C). The second-stage heating device 5 and the third-stage heating device 6 employ a high-temperature inert gas mixing heating device. The high-temperature inert gas mixing heating device includes an inert gas source pipeline and a gas injection pipe 61. The outlet end of the inert gas source pipeline extends into a corresponding vertical section and connects to the gas injection pipe 61. The injection direction of the gas injection pipe 61 is the same as the gas mist flow direction. The gas injection pipe 61 has an L-shaped structure. The second-stage heating device 5 and the third-stage heating device 6 each have 3-5 sets of gas injection pipes 61. The inert gas used is nitrogen with a purity of 99.99%, and the gas pressure is 0.5 MPa. The inert gas temperature in the second heating device is 140-160℃ (140℃ in this embodiment), and the inert gas temperature in the third-stage heating device 6 is 180-200℃ (180℃ in this embodiment).

[0029] In this embodiment, the condensation recovery device 7 is a tank-tower structure, with multiple layers of aerosol condensation baffles 8 inside, and liquid outlet pipes connected to the aerosol condensation baffles 8. The condensation recovery device 7 located in the downstream (top) horizontal section is connected to the DMSO collection tank 10 through the liquid outlet pipe, and the condensation recovery devices 7 located in the first two horizontal sections are connected to the water storage tank 9 through the liquid outlet pipe.

[0030] After the DMSO waste liquid is heated in the first vertical section, when it encounters the porous gas baffle 3, the water vapor, due to its low density and high diffusivity, separates from the other mixed gases in the evaporating gas mixture through the porous gas baffle 3. It then enters the condensation recovery device 7 (for water vapor) connected in the horizontal section, where the water vapor is condensed by the aerosol condensation baffle 8. The condensed water is transported to the water storage tank 9 through a liquid outlet pipeline for storage and reuse. The high-purity DMSO evaporating gas after the first two stages of phase separation is recovered in the condensation recovery device 7 in the third horizontal section, condensed by the aerosol condensation baffle 8, and then enters the DMSO collection box 10 for recycling in the PAN spinning system.

[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning, characterized in that, include: Evaporation multi-section combined pipeline, which includes a continuous S-shaped flow channel composed of alternating vertical and horizontal sections; The heating system is arranged in the vertical section of the multi-segment combined pipeline for gradient heating of the aerosol mixture in the pipeline. A condensation recovery system includes multiple condensation recovery devices adapted to the number of horizontal sections, each of the condensation recovery devices being connected to the corresponding horizontal section via a porous gas baffle. The multi-segment combined evaporation pipeline is equipped with a pneumatic device inside to drive the aerosol mixture to flow from bottom to top.

2. The phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning according to claim 1, characterized in that, The pneumatic device includes multiple built-in fan assemblies arranged on the inner wall of the multi-segment combined evaporation pipeline.

3. The phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning according to claim 1, characterized in that, The condensation recovery device is a tank-tower structure with multiple layers of aerosol condensation baffles inside, and the aerosol condensation baffles are connected to liquid outlet pipelines.

4. The phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning according to claim 1, characterized in that, The condensate recovery unit located on the lowest horizontal section is connected to the DMSO collection tank via a liquid outlet pipeline, while the condensate recovery units located on other horizontal sections are connected to the water storage tank via liquid outlet pipelines.

5. The phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning according to claim 1, characterized in that, The evaporation multi-segment combined pipeline includes at least three vertical segments and at least three horizontal segments. The heating system includes at least three stages of heating devices arranged sequentially along the direction of vapor flow, with the three stages of heating devices respectively arranged on different vertical segments.

6. The phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning according to claim 5, characterized in that, The heating device with at least three stages includes a first-stage heating device, a second-stage heating device, and a third-stage heating device arranged sequentially along the direction of aerosol flow.

7. The phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning according to claim 6, characterized in that, The first-stage heating device is an external linear heating element, which is wound around the outer wall of the initial vertical section of the multi-segment combined evaporation pipeline; And / or, the second-stage heating device and the third-stage heating device are high-temperature inert gas mixed-in heating devices.

8. The phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning according to claim 7, characterized in that, The high-temperature inert gas mixing heating device includes an inert gas source pipeline and a gas injection pipe. The outlet end of the inert gas source pipeline extends into the corresponding vertical section and is connected to the gas injection pipe. The injection direction of the gas injection pipe is the same as the flow direction of the gas mist.

9. The phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning according to claim 8, characterized in that, The gas injection pipe has an L-shaped structure, and the second-stage heating device and the third-stage heating device are each equipped with 3-5 sets of gas injection pipes.

10. The phase separation and recovery device for dimethyl sulfoxide-containing wastewater from polyacrylonitrile spinning according to claim 5, characterized in that, The evaporation multi-segment combined pipeline includes three vertical segments and three horizontal segments.

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