Waste gas treatment system for cyclic regeneration of chemical fibers

Abstract

The utility model discloses a waste gas treatment system for cyclically regenerating chemical fibers, which comprises a waste gas source, a normal-temperature water condenser, a chilled water condenser, an ethylene glycol spray tower, a heat accumulating type oxidation furnace, an alkali liquor spray tower and a chimney, the waste gas source, the normal-temperature water condenser, the chilled water condenser, the ethylene glycol spraying tower, the heat storage type oxidation furnace, the alkali liquor spraying tower and the chimney are sequentially communicated through gas guide pipes, a first spraying layer is arranged in the ethylene glycol spraying tower and used for spraying waste gas, and a second spraying layer is arranged in the alkali liquor spraying tower and used for spraying the waste gas. According to the utility model, methanol and ethylene glycol in the waste gas generated in the cyclic regeneration chemical fiber production are effectively recovered, the consumption of most methanol and ethylene glycol required in the regeneration chemical fiber is effectively solved, the total carbon emission in the whole technological process is reduced, and the environmental protection requirement is completely met.

Description

Technical Field

[0001] The utility model relates to waste gas treatment equipment, and more specifically, to a waste gas treatment system for recycling regenerated chemical fibers. Background Art

[0002] Polyethylene terephthalate (PET) fibers are widely used in textile clothing, automotive interiors and other fields due to their high strength and excellent chemical stability. In recent years, with the annual increase in the production of polyester fibers, the storage of waste polyester textiles has continued to grow, causing serious problems of resource waste and environmental pollution. For the recycling of waste polyester textiles, the chemical method of recycling regenerated chemical fibers is more in line with the current requirements of sustainable development compared to the traditional physical recycling method, and is an effective way to achieve high-quality recycling of waste polyester.

[0003] Among them, the alcoholysis - methanol transesterification process that uses waste textiles as raw materials, through processes such as ethylene glycol alcoholysis, impurity removal, alcoholysis liquid concentration, methanol transesterification, DMT crystallization, centrifugal separation, DMT rectification, etc., synthesizes recycled DMT (dimethyl terephthalate), and uses it as a raw material to synthesize PET polyester chips, polyester filaments and other engineering plastics. Compared with other chemical recycling methods, it has a greater product appreciation space and is the most promising process route for preparing high-quality recycled polyester (r-PET) materials in the current industry.

[0004] However, in the entire technology of recycling regenerated chemical fibers, due to the particularity of its production process and the complexity of raw materials, a large amount of high-concentration organic waste gas will be generated during the production process. Its components are mainly composed of methanol and ethylene glycol. The mixed gas composed of these waste gases will cause serious pollution to the environment and the atmosphere due to its large content and high concentration. However, if the waste gas is directly incinerated, the components in the waste gas will be wasted.

[0005] Therefore, a new solution needs to be proposed to solve this problem. Summary of the Utility Model

[0006] The purpose of the utility model is to overcome the above-mentioned deficiencies of the prior art and provide a waste gas treatment system that can treat the waste gas generated during the production process of recycling regenerated chemical fibers.

[0007] To achieve the above object, the utility model adopts the following technical solutions: An exhaust gas treatment system for recycling chemical fibers includes an exhaust gas source, a normal temperature water condenser, a chilled water condenser, an ethylene glycol spray tower, a regenerative thermal oxidizer, an alkali liquid spray tower, and a chimney. The exhaust gas source, the normal temperature water condenser, the chilled water condenser, the ethylene glycol spray tower, the regenerative thermal oxidizer, the alkali liquid spray tower, and the chimney are sequentially connected through air ducts. A first spray layer is arranged inside the ethylene glycol spray tower, and the first spray layer is used to spray the exhaust gas. A second spray layer is arranged inside the alkali liquid spray tower, and the second spray layer is used to spray the exhaust gas.

[0008] The utility model is further arranged such that an air inlet end is provided at the lower side of the ethylene glycol spray tower, and an air outlet end is formed at the top. The first spray layer is located in the middle of the ethylene glycol spray tower and is used to spray ethylene glycol on the exhaust gas.

[0009] The utility model is further arranged such that an air inlet end is provided at the lower side of the alkali liquid spray tower, and an air outlet end is formed at the top. The second spray layer is located in the middle of the alkali liquid spray tower and is used to spray alkali liquid on the exhaust gas.

[0010] The utility model is further arranged such that the regenerative thermal oxidizer is used for incinerating and treating the exhaust gas.

[0011] The utility model is further arranged such that the normal temperature water condenser and the chilled water condenser are respectively used for condensing the exhaust gas, and both include a shell and a plurality of branch pipes. A hollow inner cavity is arranged inside the shell, and the branch pipes are arranged in the inner cavity of the shell. Both ends of the branch pipes are respectively connected to an intake pipe and an outlet pipe for the exhaust gas to pass through. A condensing water inlet pipe and a condensing water outlet pipe are connected to the chamber between the shell and the branch pipes for the condensing water to pass through.

[0012] The utility model is further arranged such that the shell is in the shape of an inclined cylinder with a first end and a second end. The first end is inclined upwards, and the second end is inclined downwards. The branch pipes are inclined along the direction of the shell, and the branch pipes are parallel to each other. One side of the branch pipe close to the first end is connected to the intake pipe.

[0013] The utility model is further arranged such that a second hollow plate is arranged on one side of the inner cavity of the shell close to the second end. The second hollow plate divides the inner cavity of the shell into left and right parts. A terminal cavity is formed on one side of the inner cavity of the shell close to the second end, and the terminal cavity is connected to the condensing water inlet pipe. The first end of the shell is connected to the condensing water outlet pipe.

[0014] The utility model is further arranged such that a second hollow cavity is arranged inside the second hollow plate. A plurality of second through pipes are arranged through the second hollow plate from left to right. The second through pipes are hermetically sealed with the second hollow cavity inside the second hollow plate. Both ends of the second through pipes are respectively connected to the two chambers on the left and right sides of the second hollow plate.

[0015] The present utility model is further configured such that a second drain pipe is connected to the lower side of the second hollow cavity, and an air outlet pipe is connected to the upper side of the second hollow cavity.

[0016] The present utility model is further configured such that a partition plate is provided in the second hollow cavity. The partition plate divides the second hollow cavity into upper and lower parts. The second drain pipe communicates with the chamber below the partition plate, and the air outlet pipe communicates with the chamber above the partition plate.

[0017] The present utility model is further configured such that a first hollow plate is further provided in the inner cavity of the housing. The first hollow plate is located between the second hollow plate and the first end of the housing. A partition cavity is formed between the first hollow plate and the second hollow plate;

[0018] The present utility model is further configured such that a first hollow cavity is provided inside the first hollow plate. The branch pipe communicates with the first hollow cavity. A connecting pipe is connected between the first hollow plate and the second hollow plate, and the connecting pipe communicates the first hollow cavity and the second hollow cavity.

[0019] The present utility model is further configured such that the connecting pipe is connected to the upper side position of the first hollow cavity and the second hollow cavity; a plurality of first through pipes are provided through the first hollow plate from left to right. The first through pipes are hermetically sealed with the first hollow cavity inside the first hollow plate, and the first through pipes communicate with the two chambers on the left and right of the first hollow plate respectively.

[0020] In summary, the present utility model has the following beneficial effects:

[0021] By using a normal temperature condenser and a chilled water condenser, the waste gas can be condensed twice successively, and two different temperature condensation media can be used during the condensation process, enabling the condensation and precipitation of two different substances, and thus realizing the separation of different substances in the waste gas; and by setting an ethylene glycol spray tower, the waste gas can be sprayed with ethylene glycol. Utilizing the characteristic that methanol has high solubility in ethylene glycol, the condensed waste gas can be further purified, and the separation of methanol can be achieved as much as possible; by setting a regenerative thermal oxidizer and an alkali solution spray tower, the regenerative thermal oxidizer can incinerate the waste gas to remove the combustible organic waste gas components therein, and then perform alkali washing and spraying, thereby effectively cleaning the waste gas, effectively solving most of the consumption of methanol and ethylene glycol required in the recycled chemical fiber, reducing the total carbon emissions in the entire process, and fully meeting the environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of an exhaust gas treatment system for recycled chemical fiber in this embodiment;

[0023] Figure 2 It is a schematic structural diagram of the condenser in this embodiment.

[0024] Reference numerals: waste gas source 1; normal temperature water condenser 2; chilled water condenser 3; ethylene glycol spray tower 4; first spray layer 41; regenerative thermal oxidizer 5; caustic solution spray tower 6; second spray layer 61; chimney 7; housing 80; first end 81; second end 82; intake pipe 83; exhaust pipe 84; branch pipe 85; first hollow plate 86; first hollow cavity 861; first drain pipe 862; first through pipe 863; second hollow plate 87; second hollow cavity 871; partition plate 872; second drain pipe 873; second through pipe 874; partition cavity 88; end cavity 89; condensate inlet pipe 810; condensate outlet pipe 811; connecting pipe 812. Detailed implementation manners

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] This embodiment discloses an exhaust gas treatment system for recycling and regenerating chemical fibers. In the entire recycling and regenerating chemical fiber technology, due to the particularity of its production process and the complexity of raw materials, a large amount of high-concentration organic waste gas will be generated during production. Its components mainly consist of methanol and ethylene glycol. Due to reasons such as complex composition, large content, and high concentration of the mixed gas composed of these waste gases, direct emission will cause serious pollution to the environment and the atmosphere. In this embodiment, the exhaust gas treatment system can treat the waste gas generated during the production of recycling and regenerating chemical fibers.

[0027] Refer to Figure 1 As shown, the exhaust gas treatment system in this embodiment includes a waste gas source 1, a normal temperature water condenser 2, a chilled water condenser 3, an ethylene glycol spray tower 4, a regenerative thermal oxidizer 5, a caustic solution spray tower 6, and a chimney 7. The waste gas source 1, the normal temperature water condenser 2, the chilled water condenser 3, the ethylene glycol spray tower 4, the regenerative thermal oxidizer 5, the caustic solution spray tower 6, and the chimney 7 are sequentially connected through a conduit.

[0028] The ethylene glycol spray tower 4 is provided with a first spray layer 41 for spraying the waste gas. An intake end is provided at the lower side of the ethylene glycol spray tower 4, and an outlet end is formed at the top. The first spray layer 41 is located in the middle of the ethylene glycol spray tower 4 for spraying ethylene glycol on the waste gas.

[0029] The caustic solution spray tower 6 is provided with a second spray layer 61 for spraying the waste gas. An intake end is provided at the lower side of the caustic solution spray tower 6, and an outlet end is formed at the top. The second spray layer 61 is located in the middle of the caustic solution spray tower 6 for spraying caustic solution on the waste gas.

[0030] When the waste gas passes through the spray tower, its flow direction is from bottom to top, enabling it to meet the spray liquid in the middle, and then the waste gas can be spray-washed.

[0031] The regenerative thermal oxidizer 5 incinerates the waste gas. Under normal circumstances, the waste gas incineration can meet the required temperature of the equipment. Only natural gas is used for energy supply when the equipment starts, or natural gas can also be used for supplementary energy supply when needed.

[0032] During the waste gas treatment process, the treatment process includes the following steps:

[0033] (1) The organic waste gas source 1 discharged from the production workshop is input into the entire system. First, it passes through the normal-temperature water condenser 2 for primary condensation, and the cooling medium is 32°C circulating water; the waste gas is condensed and cooled, and most of the ethylene glycol is condensed and separated from the waste gas and discharged into the ethylene glycol collection tank;

[0034] (2) After the waste gas is condensed by the normal-temperature water condenser 2, it enters the chilled-water condenser 3 for secondary condensation, and the cooling medium is 7°C chilled water; part of the methanol in the waste gas is also condensed and separated from the waste gas, and the condensed methanol is discharged into the methanol collection tank;

[0035] (3) After the waste gas passes through the chilled-water condenser 3, it enters the ethylene glycol spray tower 4 for spray treatment, and the spraying liquid is ethylene glycol. Since methanol has high solubility in ethylene glycol, the waste gas after preliminary condensation is supplemented with spraying using ethylene glycol to basically remove the methanol in the waste gas, and an ethylene glycol-methanol mixture is discharged;

[0036] (4) After the waste gas passes through the ethylene glycol spray tower 4, it enters the regenerative thermal oxidizer 5 for incineration treatment. After incineration, the organic components in the waste gas can be basically incinerated;

[0037] (5) After the waste gas passes through the regenerative thermal oxidizer 5, it enters the caustic solution spray tower 6 for spraying, and the spraying medium is caustic solution. The incinerated waste gas is washed by the caustic solution to remove other polluting components in the waste gas;

[0038] (6) The waste gas after caustic washing can meet the emission standards and is discharged from the chimney 7, completing the waste gas treatment.

[0039] Among them, the normal-temperature water condenser 2 and the chilled-water condenser 3 can respectively condense the waste gas, forming two-stage condensation treatment in sequence.

[0040] Refer to Figure 2As shown, the structures of the normal-temperature water condenser 2 and the chilled-water condenser 3 are substantially the same, both including a housing 80 and a number of branch pipes 85. A hollow inner cavity is provided inside the housing 80, and the branch pipes 85 are arranged in the inner cavity of the housing 80. Both ends of the branch pipes 85 are respectively connected to an intake pipe 83 and an exhaust pipe 84, and the exhaust gas is supplied to pass through the branch pipes 85. A condensate inlet pipe 810 and a condensate outlet pipe 811 are connected to the chamber between the housing 80 and the branch pipes 85 for the condensate to pass through. During the process of the condensate and the exhaust gas in the branch pipes 85 flowing through the condenser, the two do not come into direct contact, and only heat transfer is achieved. The condensate can cool down the exhaust gas, thereby causing the corresponding organic gas in the exhaust gas to cool and condense to form a liquid structure. Moreover, by using the branch pipes 85 arranged side by side in multiple rows inside the housing 80, the heat conduction area between the two can be increased, and the cooling efficiency of the exhaust gas can be improved.

[0041] To facilitate the centralized convergence of the condensed liquid, the housing 80 is in the shape of an inclined cylinder, having a first end 81 and a second end 82. The first end 81 is inclined upward, and the second end 82 is inclined downward. The branch pipes 85 are also in an inclined state, arranged along the direction of the housing 80, and each branch pipe 85 is parallelly distributed and inclined downward toward the second end 82 of the housing 80.

[0042] One side of the branch pipe 85 close to the first end 81 is connected to the intake pipe 83, and the exhaust gas enters from this side of the branch pipe 85, flows along the direction of the branch pipe 85, and exchanges heat with the condensing medium outside the branch pipe 85 at the same time. Some gaseous substances in the branch pipe 85 will condense inside the branch pipe 85 and concentrate along the direction of the branch pipe 85 toward the second end 82.

[0043] A second hollow plate 87 is provided on one side of the inner cavity of the housing 80 close to the second end 82, and the second hollow plate 87 divides the inner cavity of the housing 80 into left and right parts. An end cavity 89 is formed on one side of the inner cavity of the housing 80 close to the second end 82. A first hollow plate 86 is also provided in the inner cavity of the housing 80. The first hollow plate 86 and the second hollow plate 87 are substantially parallel. The first hollow plate 86 is located between the second hollow plate 87 and the first end 81 of the housing 80, and a partition cavity 88 is formed between the first hollow plate 86 and the second hollow plate 87.

[0044] The end cavity 89 is connected to the condensate inlet pipe 810, and the first end 81 of the housing 80 is connected to the condensate outlet pipe 811. The condensing medium enters from Figure 2 the right side direction in Figure 2 and flows out from

[0045] The first hollow plate 86 is provided with a hollow cavity 861 inside. The branch pipe 85 communicates with the cavity 861. The waste gas in the branch pipe 85 can flow into the cavity 861, and the condensed medium can be gathered in the cavity 861. Moreover, a first drain pipe 862 is connected to the bottom of the cavity 861. The first drain pipe 862 extends outside the housing 80 and can discharge the condensate in the cavity 861.

[0046] In order to enable the cooling medium to flow on both sides of the first hollow plate 86, channels that penetrate from left to right need to be opened at the first hollow plate 86. Specifically, a number of first through pipes 863 are arranged through the first hollow plate 86 from left to right, and the first through pipes 863 are hermetically sealed with the cavity 861 inside the first hollow plate 86. The first through pipes 863 communicate with two chambers on the left and right of the first hollow plate 86 respectively, and thus the cooling liquid can flow between the chambers on both sides.

[0047] A second hollow cavity 871 is provided inside the second hollow plate 87. A connecting pipe 812 is connected between the first hollow plate 86 and the second hollow plate 87. The connecting pipe 812 communicates with the cavity 861 and the cavity 871. Moreover, the connecting pipe 812 is connected to the upper side positions of the cavity 861 and the cavity 871, mainly for the waste gas at the upper layer positions inside the first hollow plate 86 and the second hollow plate 87 to exchange and flow.

[0048] In order to enable the cooling medium to flow on both sides of the second hollow plate 87, channels that penetrate from left to right are also opened at the second hollow plate 87, and its structure is roughly similar to that of the first hollow plate 86. A number of second through pipes 874 are arranged through the second hollow plate 87 from left to right. The second through pipes 874 are hermetically sealed with the second hollow cavity 871 inside the second hollow plate 87. The two ends of the second through pipes 874 communicate with two chambers on the left and right of the second hollow plate 87 respectively, and the cooling liquid can flow between the chambers on both sides.

[0049] In order to discharge the cooling liquid, a second drain pipe 873 is connected to the lower side of the cavity 871, and an exhaust pipe 84 is connected to the upper side of the cavity 871. The waste gas entering the condenser is discharged from the exhaust pipe 84 on the upper side of the cavity 871 after passing through the branch pipe 85, the cavity 861 and the cavity 871, realizing the flow of the waste gas.

[0050] By successively arranging two chambers for discharging the condensate inside the housing 80, the condensate can be normally discharged. Most of the components to be condensed will gather in the cavity 861, and the cavity 871 plays a supplementary role. The exhaust pipe 84 for discharging the waste gas is located at the upper side position of the cavity 871.

[0051] Further, a partition plate 872 is provided in the second hollow cavity 871. The partition plate 872 can divide the second hollow cavity 871 into upper and lower parts, so that the upper and lower chambers can be directly separated and cannot communicate. Moreover, the second drain pipe 873 is communicated with the chamber below the partition plate 872, and the air outlet pipe 84 is communicated with the chamber above the partition plate 872. The partition plate 872 can block the position where the condensate accumulates below and the position where the waste gas is discharged, can extend the flow distance between the condensate discharge port and the waste gas discharge port, increase the bending of the channel, and can minimize the contact between the waste gas and the condensation medium, thereby avoiding the condensation medium being re-carried into the waste gas.

[0052] The above description is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions within the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An exhaust gas treatment system for recycling chemical fibers, characterized in that, It includes an exhaust gas source (1), a normal temperature water condenser (2), a chilled water condenser (3), an ethylene glycol spray tower (4), a regenerative thermal oxidizer (5), an alkali solution spray tower (6) and a chimney (7). The exhaust gas source (1), the normal temperature water condenser (2), the chilled water condenser (3), the ethylene glycol spray tower (4), the regenerative thermal oxidizer (5), the alkali solution spray tower (6) and the chimney (7) are sequentially connected through air ducts. A first spray layer (41) is arranged inside the ethylene glycol spray tower (4), and the first spray layer (41) is used for spraying the exhaust gas. A second spray layer (61) is arranged inside the alkali solution spray tower (6), and the second spray layer (61) is used for spraying the exhaust gas.

2. The waste gas treatment system for recycling chemical fibers according to claim 1, characterized in that, An air inlet end is arranged at the lower side of the ethylene glycol spray tower (4), and an air outlet end is formed at the top. The first spray layer (41) is located in the middle of the ethylene glycol spray tower (4) and is used for spraying ethylene glycol on the exhaust gas; An air inlet end is arranged at the lower side of the alkali solution spray tower (6), and an air outlet end is formed at the top. The second spray layer (61) is located in the middle of the alkali solution spray tower (6) and is used for spraying alkali solution on the exhaust gas.

3. An exhaust gas treatment system for recycling chemical fibers according to claim 2, characterized in that, The regenerative thermal oxidizer (5) is used for incinerating and treating the exhaust gas.

4. An exhaust gas treatment system for recycling chemical fibers according to claim 1, characterized in that, The normal temperature water condenser (2) and the chilled water condenser (3) are respectively used for condensing the exhaust gas. Both include a shell (80) and a number of branch pipes (85). A hollow inner cavity is arranged inside the shell (80). The branch pipes (85) are arranged in the inner cavity of the shell (80). Both ends of the branch pipes (85) are respectively connected to an inlet pipe (83) and an outlet pipe (84) for the exhaust gas to pass through. A condensation inlet pipe (810) and a condensation outlet pipe (811) are connected to the chamber between the shell (80) and the branch pipes (85) for the condensed water to pass through.

5. An exhaust gas treatment system for recycling chemical fibers according to claim 4, characterized in that, The shell (80) is in the shape of an inclined cylinder structure with a first end (81) and a second end (82). The first end (81) is inclined upwards, and the second end (82) is inclined downwards. The branch pipes (85) are arranged obliquely along the direction of the shell (80), and the branch pipes (85) are arranged in parallel. One side of the branch pipes (85) close to the first end (81) is connected to the inlet pipe (83).

6. The waste gas treatment system for recycling chemical fibers according to claim 4, characterized in that, A second hollow plate (87) is arranged on one side of the inner cavity of the shell (80) close to the second end (82). The second hollow plate (87) divides the inner cavity of the shell (80) into left and right parts. A terminal cavity (89) is formed on one side of the inner cavity of the shell (80) close to the second end (82). The terminal cavity (89) is connected to the condensation inlet pipe (810), and the first end (81) of the shell (80) is connected to the condensation outlet pipe (811).

7. An exhaust gas treatment system for recycling chemical fibers according to claim 6, characterized in that, A second hollow cavity (871) is arranged inside the second hollow plate (87). A number of second through pipes (874) penetrate through the second hollow plate (87) from left to right. The second through pipes (874) are hermetically sealed with the second hollow cavity (871) inside the second hollow plate (87). Both ends of the second through pipes (874) are respectively connected to the two chambers on the left and right sides of the second hollow plate (87); A drain pipe two (873) is connected to the lower side of the second hollow cavity (871), and an outlet pipe (84) is connected to the upper side of the second hollow cavity (871).

8. An exhaust gas treatment system for recycling chemical fibers according to claim 7, characterized in that, A partition plate (872) is provided in the second hollow cavity (871). The partition plate (872) divides the second hollow cavity (871) into upper and lower parts. The second drain pipe (873) communicates with the chamber below the partition plate (872), and the air outlet pipe (84) communicates with the chamber above the partition plate (872).

9. An exhaust gas treatment system for recycling chemical fibers according to claim 5, characterized in that, A first hollow plate (86) is further provided in the inner cavity of the housing (80). The first hollow plate (86) is located between the second hollow plate (87) and the first end (81) of the housing (80). A partition cavity (88) is formed between the first hollow plate (86) and the second hollow plate (87); A first hollow cavity (861) is provided inside the first hollow plate (86). The branch pipe (85) communicates with the first hollow cavity (861). A connecting pipe (812) is connected between the first hollow plate (86) and the second hollow plate (87), and the connecting pipe (812) communicates the first hollow cavity (861) and the second hollow cavity (871).

10. An exhaust gas treatment system for recycling chemical fibers according to claim 9, characterized in that, The connecting pipe (812) is connected to the upper side positions of the first hollow cavity (861) and the second hollow cavity (871); A plurality of first through pipes (863) are arranged through the first hollow plate (86) from left to right. The first through pipes (863) are hermetically sealed with the first hollow cavity (861) inside the first hollow plate (86), and the first through pipes (863) communicate with the two chambers on the left and right of the first hollow plate (86) respectively.

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