Carbonization tail gas deamination system in carbon fiber production and carbon fiber production system

Abstract

The utility model relates to a carbonization tail gas deamination system in carbon fiber production and a carbon fiber production system. The carbonization tail gas deamination system in carbon fiber production comprises a plurality of stages of deamination reactors and circulation tanks which are alternately communicated, the adjacent next-stage circulation tank is communicated with the adjacent previous-stage circulation tank, all the deamination reactors are provided with feed ports and discharge ports, the circulation tanks are communicated with the feed ports of the corresponding stages of deamination reactors, and the discharge ports of the corresponding stages of deamination reactors are communicated with the discharge ports of the corresponding stages of deamination reactors. And the communication pipeline between the first-stage circulating tank and the feeding hole of the first-stage deamination reactor is also communicated with an ammonium sulfate storage container. In the utility model, the sulfuric acid concentration and the pH value in the system in the last stage of circulation tank are the highest, the sulfuric acid concentration and the pH value in the system in the first stage of circulation tank are the lowest, and the ammonium sulfate solution generated by the reaction is fed into the ammonium sulfate storage container through the communication pipeline between the first stage of circulation tank and the ammonium sulfate storage container; furthermore, the obtained ammonium sulfate solution contains less sulfate ions, and the purity of an ammonium sulfate product is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical production equipment, and in particular relates to a carbonized tail gas deammoniation system in carbon fiber production and a carbon fiber production system. Background Art

[0002] Carbon fiber is a fibrous carbon material that has developed rapidly since the 1960s. Specifically, carbon fiber is a fiber with a carbon content of over 90% made from polyacrylonitrile (PAN), pitch, viscose, and other raw materials through oxidation and carbonization. Carbon fiber has the advantages of high specific strength, high modulus, high temperature resistance, corrosion resistance, creep resistance, electrical conductivity, thermal conductivity, and a low thermal expansion coefficient. Combining the inherent properties of carbon materials with the softness and processability of the fiber, carbon fiber is a reinforcing material that can be used as a reinforcement for matrices such as resins, ceramics, and metals. It is widely used in aerospace, military, sports and leisure products, transportation (such as automobiles and ships), medical equipment, civil engineering, bioengineering, chemical machinery, textile machinery, and other fields.

[0003] Based on the raw material type, carbon fibers are classified into polyacrylonitrile (PAN)-based, pitch-based, and viscose-based types. Polyacrylonitrile (PAN)-based carbon fibers, with their advantages of superior finished product quality, simple processing, and excellent mechanical properties, are currently the mainstream type of carbon fibers, accounting for over 90% of global production.

[0004] The production process for polyacrylonitrile-based carbon fibers involves oxidation, low-temperature carbonization, high-temperature carbonization, surface treatment, and sizing of polyacrylonitrile precursor fibers into carbon fibers. The low-temperature and high-temperature carbonization processes are performed in an oxygen-free environment, during which non-carbon molecules (such as ammonia and hydrogen cyanide) are removed and discharged from the furnace. In the prior art, combustion is commonly used to treat the exhaust gas generated during the carbonization process. However, this treatment method is ineffective, and the treated exhaust gas still fails to meet emission standards, causing environmental pollution.

[0005] Patent publication number CN118179237A discloses a device for treating ammonia-containing waste gas. This device uses a multi-stage countercurrent absorption process to treat ammonia, recovering the ammonia from the waste gas and producing ammonium sulfate. However, the resulting ammonium sulfate product, treated with this device, is of low purity, highly acidic, and contains a high concentration of free sulfate ions (derived from sulfuric acid). Utility Model Content

[0006] In view of this, the utility model provides a carbonization tail gas deammoniation system and a carbon fiber production system in carbon fiber production to solve the technical problems that the ammonium sulfate product obtained by treating the ammonia-containing waste gas is of low purity, has strong acidity, and contains a large amount of free sulfate ions.

[0007] In order to realize the above scheme, the technical solution of the present utility model is as follows:

[0008] In the first aspect, the utility model provides a tail gas deamination system, which includes several levels of alternately connected deamination reactors and circulation tanks, the adjacent lower-level circulation tanks are connected to the adjacent upper-level circulation tanks, all of the circulation tanks are provided with a first liquid level gauge, all of the deamination reactors are provided with a feed port and a discharge port, the circulation tanks are connected to the feed ports of the deamination reactors of the corresponding levels, and the connecting pipe between the first-stage circulation tank and the feed port of the first-stage deamination reactor is also connected to an ammonium sulfate storage container.

[0009] The principle of the tail gas deamination system of the present invention is as follows: by setting up several levels of alternately connected deamination reactors and circulation tanks, the adjacent lower-level circulation tanks are connected to the adjacent upper-level circulation tanks, all the circulation tanks are provided with a first liquid level gauge, all the deamination reactors are provided with a feed port and a discharge port, the circulation tanks are connected to the feed ports of the deamination reactors of the corresponding levels, and the connecting pipe between the first-level circulation tank and the feed port of the first-level deamination reactor is also connected to an ammonium sulfate storage container, which can make the conveying direction of the tail gas opposite to the conveying direction of the sulfuric acid solution, that is, the ammonia is treated in a countercurrent manner, and the sulfuric acid solution is continuously introduced into the last-level circulation tank, and the sulfuric acid solution gradually flows from the last-level circulation tank through the upper-level circulation tank to the first-level circulation tank and then enters the first-level deamination reactor, and the tail gas to be treated is introduced into the first-level deamination reactor, and the ammonia in the tail gas reacts with the sulfuric acid solution to generate ammonium sulfate. After the reaction, The system gradually passes through the first-stage circulation tank and enters the adjacent next-stage deamination reactor in sequence. Sulfuric acid solution is fed into the deamination reactor through the circulation tank of this level. Unreacted ammonia in the system continues to react with sulfuric acid, and so on until the system enters the last-stage deamination reactor and continues to react in the last-stage deamination reactor. After the reaction, it is fed into the last-stage circulation tank. The material is transported to the adjacent previous-stage circulation tank along the direction of sulfuric acid delivery in the opposite direction to the tail gas delivery direction until it enters the first-stage circulation tank. That is, the sulfuric acid concentration in the system in the last-stage circulation tank is the highest and the pH is the lowest, and the sulfuric acid concentration in the system in the first-stage circulation tank is the lowest and the pH is the highest. The ammonium sulfate solution generated by the reaction is fed into the ammonium sulfate storage container through the connecting pipe between the first-stage circulation tank and the ammonium sulfate storage container, thereby ensuring that the obtained ammonium sulfate solution contains less sulfate ions, thereby improving the purity of the ammonium sulfate product.

[0010] Optionally, all the circulation tanks are provided with a first liquid level gauge and a lower liquid port, and the first liquid level gauge is electrically connected to the lower liquid port.

[0011] Specifically, the utility model electrically connects the first liquid level meter to the lower liquid port of the circulation tank of the corresponding level, and can open the lower liquid port of the circulation tank when the first liquid level meter monitors that the liquid level in the circulation tank reaches the first preset liquid level threshold, thereby realizing automatic control.

[0012] Optionally, the deamination reactor is provided with a second liquid level gauge, and the discharge port is electrically connected to the second liquid level gauge of the deamination reactor of the corresponding level.

[0013] Specifically, the utility model is to configure the deamination reactor with a second liquid level gauge and electrically connect the discharge port to the second liquid level gauge, so that the material in the deamination reactor can be automatically discharged in time when the liquid level reaches a certain level, thereby improving the processing efficiency.

[0014] Optionally, the last-stage circulation tank is provided with a feed pipe, the feed pipe is provided with a flow regulating valve, and the flow regulating valve is connected to the first liquid level meter signal of the last-stage circulation tank.

[0015] Specifically, the utility model provides a flow regulating valve on the feed pipe connected to the last-stage circulation tank, and connects the flow regulating valve to the signal of the first liquid level meter of the last-stage circulation tank. When the liquid level in the last-stage circulation tank reaches a certain level, the flow regulating valve can automatically reduce the flow of the sulfuric acid solution, thereby avoiding the negative impact of too much material in the last-stage circulation tank on production.

[0016] Optionally, the last-stage circulation tank is provided with a feed pipe, the feed pipe is provided with a flow regulating valve, and the flow regulating valve is connected to the first liquid level meter signal of the last-stage circulation tank.

[0017] Optionally, a circulation pump is provided on the communicating pipe between the circulation tank and the feed inlet of the adjacent upper-stage deamination reactor.

[0018] Optionally, the tail gas deamination system further includes a cooling mechanism, and the cooling mechanism is located on the connecting pipe between the circulation pump and the feed inlet.

[0019] Specifically, the utility model adds a cooling mechanism to the connecting pipe between the circulation pump and the feed port, so that the acid liquid can be cooled by the cooling mechanism to reduce the heat released during the dilution of concentrated sulfuric acid (a mixture of concentrated sulfuric acid and water is usually introduced during the production process), thereby avoiding safety hazards caused by excessive heat in production.

[0020] Optionally, the tail gas deammonification system further includes a gas-liquid separation mechanism, and the last-stage circulation tank is provided with a gas outlet, which is connected to the gas-liquid separation mechanism.

[0021] Specifically, the utility model connects the gas outlet of the last-stage circulation tank with the gas-liquid separation mechanism, and can separate the gas and liquid of the deammoniation system through the gas-liquid separation mechanism, so as to facilitate the recovery of substances such as ammonium sulfate in the system and increase economic benefits.

[0022] Optionally, the tail gas deamination system further includes a hydroxyacetonitrile reactor, and the gas-liquid separation mechanism is provided with an exhaust port and a liquid discharge port, and the exhaust port is connected to the hydroxyacetonitrile reactor.

[0023] Specifically, the utility model connects the exhaust port of the gas-liquid separation mechanism with the hydroxyacetonitrile reactor, thereby sending hydrogen cyanide gas in the tail gas into the hydroxyacetonitrile reactor, and then producing hydroxyacetonitrile using hydrogen cyanide gas as a raw material. While recovering the hydrogen cyanide gas in the tail gas, the resource utilization rate is improved and the economic benefits are increased.

[0024] Optionally, the drain port is connected to the last-stage circulation tank.

[0025] Specifically, the utility model connects the discharge port of the gas-liquid separation mechanism with the last-stage circulation tank, thereby being able to send the ammonium sulfate solution in the system into the last-stage circulation tank, thereby facilitating the recovery of substances such as ammonium sulfate in the system and increasing profits.

[0026] Optionally, a packing section and a tray section are sequentially provided between the feed port and the discharge port, and the tray section is provided with a plurality of sieve plates located on the side wall from top to bottom.

[0027] Specifically, the utility model arranges a packing section and a tower plate section in sequence between the feed port and the discharge port of the deamination reactor, and arranges a plurality of sieve plates located on the side walls of the tower plate section from top to bottom, thereby ensuring the absorption effect of the tail gas through the packing, and preventing the extremely small amount of tar contained in the exhaust gas from clogging the deamination reactor through the plurality of sieve plates located on the side walls arranged from top to bottom of the tower plate section, thereby ensuring the smooth progress of production.

[0028] Optionally, a spray assembly is provided on the top of the deamination reactor, and the spray assembly is connected to the feed inlet.

[0029] Specifically, the utility model sets a spray assembly on the top of the deamination reactor and connects the spray assembly to the feed port, so as to increase the contact area between dilute sulfuric acid and other substances and the tail gas through the spray assembly, thereby better removing ammonia and other substances in the tail gas.

[0030] In a second aspect, the present invention provides a carbon fiber production system, which includes the tail gas deamination system as described above.

[0031] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, serving to explain the principles of the present application. It is obvious that the drawings described below are merely some embodiments of the present application, and a person of ordinary skill in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0033] Figure 1 Schematic diagram of the structure of the tail gas deamination system of Example 1;

[0034] Figure 2 Schematic diagram of the structure of the tail gas deamination system of Example 2;

[0035] Figure 3 Schematic diagram of the structure of the tail gas deamination system of Example 3;

[0036] Figure 4 This is a schematic structural diagram of the tail gas deamination system of Example 4.

[0037] Reference numerals

[0038] 1-deamination reactor, 11-second liquid level gauge, 12-packing section, 13-tray section, 131-sieve plate;

[0039] 2-circulation tank, 21-first liquid level gauge, 22-flow regulating valve;

[0040] 3-circulation pump;

[0041] 4-Cooling mechanism;

[0042] 5-Ammonium sulfate storage container;

[0043] 6-Gas-liquid separation mechanism;

[0044] 7-Hydroxyacetonitrile reactor; DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] It should be noted that all directional indications (such as up, down, top, bottom, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0047] In this utility model, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0048] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "A and / or B" appearing in the full text is to include three parallel schemes, with "A and / or B" including scheme A, or scheme B, or a scheme in which both A and B are satisfied. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention. In related technologies, combustion emissions are generally used to treat the exhaust gas generated by the carbonization process. However, this treatment method has a poor treatment effect, and the exhaust gas after treatment still cannot meet the emission standards, which still causes environmental pollution problems. Based on the above technical problems, one embodiment of the present invention provides a tail gas deamination system, comprising a plurality of stages of alternately connected deamination reactors 1 and circulation tanks 2, that is, a circulation tank 2 is provided on the connecting pipes between adjacent deamination reactors 1 and downstream of the last stage of deamination reactor 1;

[0049] All circulation tanks 2 are provided with a first liquid level gauge 21 and a lower liquid port. The first liquid level gauge 21 is electrically connected to the lower liquid port of the corresponding level circulation tank. The adjacent lower level circulation tank 2 is connected to the adjacent upper level circulation tank 2.

[0050] The deamination reactor 1 is provided with a second liquid level gauge 11. A spray assembly is provided on the top of the deamination reactor 1. All deamination reactors 1 are provided with a feed port and a discharge port. A packing section 12 and a tray section 13 are sequentially provided between the feed port and the discharge port. The tray section 13 is provided with a plurality of sieve plates 131 located on the side wall from top to bottom. The spray assembly is connected to the feed port, and the discharge port is electrically connected to the second liquid level gauge 11 of the deamination reactor 1 of the corresponding level.

[0051] The circulation tank 2 is connected to the feed inlet of the adjacent upper-level deamination reactor 1, and a circulation pump 3 is provided on the connecting pipe between the circulation tank 2 and the feed inlet of the corresponding level deamination reactor 1;

[0052] The communication pipe between the first-stage circulation tank 2 and the feed port of the first-stage deamination reactor 1 is also connected to the ammonium sulfate storage container 5.

[0053] In another embodiment of the present invention, the last-stage circulation tank 2 is provided with a feed pipe, and a flow regulating valve 22 is provided on the feed pipe. The flow regulating valve 22 is signal-connected to the first liquid level meter 21 of the last-stage circulation tank 2 .

[0054] In another embodiment of the present invention, the tail gas deamination system further includes a cooling mechanism 4 , which is located on the communication pipe between the circulation pump 3 and the feed inlet.

[0055] In another embodiment of the present invention, the tail gas deamination system also includes a hydroxyacetonitrile reactor 7, the last-stage circulation tank 2 is provided with an air outlet, the air outlet is connected to a gas-liquid separation mechanism 6, the gas-liquid separation mechanism 6 is provided with an exhaust port and a drain port, the exhaust port is connected to the hydroxyacetonitrile reactor 7, and the drain port is connected to the last-stage circulation tank 2.

[0056] The present invention is described in detail below through specific examples. It should also be understood that the following examples are only used to specifically illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, that is, those skilled in the art can make selections within a suitable range based on the description herein, and are not limited to the specific values ​​in the following examples.

[0057] Example 1

[0058] See also Figure 1 , Figure 1 Schematic diagram of the structure of the tail gas deamination system of this embodiment, the tail gas deamination system includes several stages of alternately connected deamination reactors 1 and circulation tanks 2, and the number of deamination reactors 1 is the same as the number of circulation tanks 2.

[0059] like Figure 1 As shown, the deamination reactor 1 is used to remove ammonia from the tail gas. A spray assembly (not shown) is installed at the top of the deamination reactor 1. All deamination reactors 1 have an exhaust gas inlet and feed port located at the top, connected to the spray assembly. All deamination reactors 1 have a discharge port located at the bottom. A packing section 12 and a tray section 13 are located between the feed and discharge ports. The tray section 13 is equipped with several sieve plates 131 located on the sidewalls from top to bottom. The spray assembly is connected to the feed port. Each deamination reactor 1 is equipped with a second liquid level gauge 11, which is electrically connected to the discharge port of the corresponding deamination reactor 1. The feed port serves as an inlet for substances such as sulfuric acid solution to enter the deamination reactor 1. Within the deamination reactor 1, the sulfuric acid reacts with ammonia in the tail gas to produce ammonium sulfate and water, thereby removing ammonia from the tail gas.

[0060] Specifically, this embodiment arranges a packing section 12 and a tray section 13 in sequence between the feed port and the discharge port of the deamination reactor 1, and arranges a plurality of sieve plates 131 on the side walls of the tray section 13 from top to bottom. This ensures the absorption effect of the tail gas through the packing, and prevents the extremely small amount of tar contained in the tail gas from clogging the deamination reactor 1 by the sieve plates 131 arranged on the side walls of the tray section 13 from top to bottom, thereby ensuring the smooth progress of production. By arranging a spray assembly at the top of the deamination reactor 1 and connecting the spray assembly to the feed port, the contact area between dilute sulfuric acid and other substances in the tail gas can be increased by the spray assembly, thereby better removing ammonia and other substances in the tail gas. By arranging the deamination reactor 1 to be provided with a second liquid level gauge 11 and electrically connecting the second liquid level gauge 11 to the discharge port of the deamination reactor 1 of the corresponding level, the material liquid level in the deamination reactor 1 can be automatically discharged in a timely manner when it reaches a certain level, thereby improving the processing efficiency.

[0061] Please continue reading Figure 1 , a circulation tank 2 is provided on the connecting pipes between adjacent deamination reactors 1 and downstream of the last-stage deamination reactor 1, and the adjacent lower-stage circulation tank 2 is connected to the adjacent upper-stage circulation tank 2. All circulation tanks 2 are provided with an acid liquid inlet, a first liquid level gauge 21 and a lower liquid port, and the first liquid level gauge 21 is electrically connected to the lower liquid port of the corresponding level. The lower liquid port of the circulation tank 2 is connected to the feed port of the deamination reactor 1 of the corresponding level, and a circulation pump 3 is provided on the connecting pipe between the lower liquid port of the circulation tank 2 and the feed port of the deamination reactor 1 of the corresponding level. The circulation pump 3 is used to pump the sulfuric acid solution in the circulation tank 2 to the deamination reactor 1 of the corresponding level and the adjacent upper-stage circulation tank 2.

[0062] Specifically, this embodiment electrically connects the first liquid level meter 21 to the lower liquid port of the circulation tank 2 of the corresponding level. When the first liquid level meter 21 detects that the liquid level in the circulation tank 2 reaches the first preset liquid level threshold, the lower liquid port of the circulation tank 2 is opened, thereby realizing automatic control and improving efficiency.

[0063] Please continue reading Figure 1 The communicating pipe between the first-stage circulation tank 2 and the feed port of the first-stage deamination reactor 1 is also connected to an ammonium sulfate storage container 5, which is used as a place for storing ammonium sulfate solution.

[0064] The principle of the tail gas deamination system of this embodiment is as follows: by setting up several levels of alternately connected deamination reactors 1 and circulation tanks 2, the adjacent lower-level circulation tanks are connected to the adjacent upper-level circulation tanks, all circulation tanks 2 are provided with a first liquid level gauge 21, and all deamination reactors 1 are provided with a feed port and a discharge port. The circulation tank 2 is connected to the feed port of the deamination reactor 1 of the corresponding level, and the connecting pipe between the first-level circulation tank 2 and the feed port of the first-level deamination reactor 1 is also connected to the ammonium sulfate storage container 5, which can make the conveying direction of the tail gas opposite to the conveying direction of the sulfuric acid solution, that is, the ammonia is treated in a countercurrent manner, and the sulfuric acid solution is continuously introduced into the last-level circulation tank 2. The sulfuric acid solution gradually flows from the last-level circulation tank 2 to the first-level circulation tank 2 and then enters the first-level deamination reactor 1. The tail gas to be treated is introduced into the first-level deamination reactor 1, and the ammonia in the tail gas reacts with the sulfuric acid solution to generate ammonium sulfate. After the reaction, the system gradually The materials enter the adjacent next-stage deamination reactor 1 in sequence through the first-stage circulation tank 2, and sulfuric acid solution is fed into the deamination reactor 1 through the circulation tank 2 of this level. The unreacted ammonia in the system continues to react with sulfuric acid, and so on, until the system enters the last-stage deamination reactor 1, and continues to react in the last-stage deamination reactor 1. After the reaction, the materials are fed into the last-stage circulation tank 2, and the materials are fed to the adjacent previous-stage circulation tank 2 along the direction of sulfuric acid feeding in the opposite direction to the tail gas feeding direction until the first-stage circulation tank 2. That is, the sulfuric acid concentration in the system of the last-stage circulation tank 2 is the highest and the pH is the lowest, and the sulfuric acid concentration in the system of the first-stage circulation tank 2 is the lowest and the pH is the highest. The ammonium sulfate solution generated by the reaction is fed into the ammonium sulfate storage container 5 through the connecting pipe between the first-stage circulation tank 2 and the ammonium sulfate storage container 5, thereby ensuring that the obtained ammonium sulfate solution contains less sulfate ions, thereby improving the purity of the ammonium sulfate product.

[0065] It should be noted that, in this embodiment, all the connecting pipes are provided with switch valves (not shown) and centrifugal pumps (not shown).

[0066] The process of removing ammonia from tail gas using the system of this embodiment is as follows:

[0067] Sulfuric acid solution is fed into the last stage circulation tank 2 through the acid solution inlet. During this process, the first liquid level meter 21 monitors the liquid level in the last stage circulation tank 2.

[0068] If the first liquid level gauge 21 detects that the liquid level in the last-stage circulation tank 2 reaches the first preset liquid level threshold, the lower liquid port of the last-stage circulation tank 2 is automatically opened, and the switch valve on the connecting pipe between the lower liquid port and the adjacent upper-stage circulation tank 2 is opened, and the acid solution is pumped into the adjacent upper-stage circulation tank 2 by the circulation pump 3. During this process, the first liquid level gauge 21 monitors the liquid level in the adjacent first-stage circulation tank 2;

[0069] In this way, until the liquid level in the first-stage circulation tank 2 reaches the first preset liquid level threshold, the lower liquid port of the first-stage circulation tank 2 is automatically opened, and the switch valve on the connecting pipe between the first-stage circulation tank 2 and the first-stage deamination reactor 1 is opened, the sulfuric acid solution is pumped into the first-stage deamination reactor 1, and the tail gas to be treated is introduced into the first-stage deamination reactor 1; in the first-stage deamination reactor 1, the sulfuric acid reacts with the ammonia in the tail gas to produce ammonium sulfate and water. During this process, the second liquid level meter 11 detects the liquid level in the first-stage deamination reactor 1;

[0070] If the second liquid level meter 11 detects that the liquid level in the first-stage deamination reactor 1 reaches the second preset liquid level threshold, the discharge port of the first-stage deamination reactor 1 is automatically opened, and the connecting pipe between the discharge port of the first-stage deamination reactor 1 and the first-stage circulation tank 2 and the connecting pipe between the first-stage circulation tank 2 and the feed port of the second-stage deamination reactor 1 are opened, and the reaction mixture is fed into the second-stage deamination reactor 1. In the second-stage deamination reactor 1, sulfuric acid reacts with unreacted ammonia in the system to generate ammonium sulfate and water. During this process, the second liquid level meter 11 detects the liquid level in the second-stage deamination reactor 1;

[0071] This continues until the system after the reaction is sent to the last-stage deamination reactor 1. In the last-stage deamination reactor 1, sulfuric acid reacts with the unreacted ammonia in the system to produce ammonium sulfate and water. During this process, the second liquid level meter 11 detects the liquid level in the last-stage deamination reactor 1.

[0072] If the second liquid level meter 11 detects that the liquid level in the last-stage deamination reactor 1 reaches the second preset liquid level threshold, the discharge port of the last-stage deamination reactor 1 is automatically opened, and the on-off valve on the connecting pipe between the last-stage deamination reactor 1 and the last-stage circulation tank 2 is opened, and the reacted system is sent to the last-stage circulation tank 2;

[0073] The first liquid level meter 21 monitors the liquid level in the last stage circulation tank 2;

[0074] If the first liquid level gauge 21 detects that the liquid level in the last-stage circulation tank 2 reaches the third preset liquid level threshold, the lower liquid port of the last-stage circulation tank 2 is automatically opened, and the switch valve on the connecting pipe between the lower liquid port and the adjacent upper-stage circulation tank 2 is opened, and the acid solution is pumped into the adjacent upper-stage circulation tank 2 by the circulation pump 3. During this process, the first liquid level gauge 21 monitors the liquid level in the adjacent first-stage circulation tank 2;

[0075] This continues until the post-reaction system is sent into the first-stage circulation tank 1. During this process, the first liquid level meter 21 monitors the liquid level in the adjacent first-stage circulation tank 2.

[0076] If the first liquid level meter 21 detects that the liquid level in the first-stage circulation tank 2 reaches the third preset liquid level threshold, the lower liquid port of the first-stage circulation tank 2 is automatically opened, and the switch valve on the connecting pipe between the lower liquid port and the ammonium sulfate storage container 5 is opened, and the ammonium sulfate solution is sent into the ammonium sulfate storage container 5.

[0077] Example 2

[0078] In another embodiment of the present invention, the last-stage circulation tank 2 is provided with a feed pipe, and a flow regulating valve 22 is provided on the feed pipe. The flow regulating valve 22 is signal-connected to the first liquid level meter 21 of the last-stage circulation tank 2 .

[0079] Specifically, this embodiment sets a flow regulating valve 22 on the feed pipe connected to the last-stage circulation tank 2, and connects the flow regulating valve 22 to the signal of the first liquid level meter 21 of the last-stage circulation tank 2. When the liquid level in the last-stage circulation tank 2 reaches a certain level, the flow regulating valve 22 can automatically reduce the flow of the sulfuric acid solution, thereby avoiding the negative impact of too much material in the last-stage circulation tank 2 on production.

[0080] Example 3

[0081] See also Figure 3 , Figure 3 Schematic diagram of the structure of the tail gas deamination system of this embodiment.

[0082] like Figure 3 As shown, this embodiment differs from Example 2 in that it further includes a cooling mechanism 4 located in the communication pipe between the circulation pump 3 and the feed inlet of the adjacent, previous-stage deamination reactor 1. The cooling mechanism 4 is used to reduce the temperature of the introduced sulfuric acid solution (if a mixture of concentrated sulfuric acid and water is introduced, the concentrated sulfuric acid releases heat during the dilution process). The cooling mechanism 4 can be a condenser, which is conventional and will not be described in detail here.

[0083] Specifically, this embodiment provides a cooling mechanism 4 on the connecting pipe between the circulation pump 3 and the feed port of the adjacent upper-stage deamination reactor 1. The cooling mechanism can cool the acid solution to reduce the heat released during the dilution process of concentrated sulfuric acid (a mixture of concentrated sulfuric acid and water is usually introduced during the production process), thereby avoiding safety hazards caused by excessive heat in production.

[0084] Example 4

[0085] See also Figure 4 , Figure 4 Schematic diagram of the structure of the tail gas deamination system of this embodiment.

[0086] like Figure 4 As shown, the difference between this embodiment and embodiment 3 is that: it also includes a gas-liquid separation mechanism 6, the last-stage circulation tank 2 is provided with an air outlet, the air outlet is connected to the gas-liquid separation mechanism 6, the gas-liquid separation mechanism 6 is provided with an exhaust port and a liquid discharge port, the exhaust port is connected to the hydroxyacetonitrile reactor 7, and the liquid discharge port is connected to the last-stage circulation tank 2. The gas-liquid separation mechanism 6 can adopt a gas-liquid separator, a gas buffer tank, etc. The gas-liquid separator and the gas buffer tank are existing technologies and are not described here.

[0087] Specifically, this embodiment connects the gas outlet of the final circulation tank 2 to the gas-liquid separation mechanism 6, which allows the deammoniation system to undergo gas-liquid separation via the gas-liquid separation mechanism 6, facilitating the recovery of substances such as ammonium sulfate from the system and increasing economic benefits. By connecting the exhaust port of the gas-liquid separation mechanism 6 to the hydroxyacetonitrile reactor 7, hydrogen cyanide gas in the tail gas can be fed into the hydroxyacetonitrile reactor 7, thereby producing hydroxyacetonitrile using hydrogen cyanide gas as a raw material. While recovering hydrogen cyanide gas from the tail gas, this improves resource utilization and increases economic benefits. By connecting the drain port of the gas-liquid separation mechanism 6 to the final circulation tank 2, ammonium sulfate solution in the system can be fed into the final circulation tank 2, facilitating the recovery of substances such as ammonium sulfate from the system and increasing revenue.

[0088] Another embodiment of the present invention further provides a carbon fiber production system, which includes the tail gas deamination system as described above.

[0089] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed in the present invention are intended to be covered by the claims of the present invention.

Claims

1. A tail gas deamination system, characterized in that: The tail gas deamination system includes several levels of alternately connected deamination reactors and circulation tanks, the adjacent lower-level circulation tanks are connected to the adjacent upper-level circulation tanks, all of the deamination reactors are provided with feed ports and discharge ports, the circulation tanks are connected to the feed ports of the corresponding levels of deamination reactors, and the connecting pipe between the first-stage circulation tank and the feed port of the first-stage deamination reactor is also connected to an ammonium sulfate storage container.

2. The tail gas deamination system according to claim 1, characterized in that: All the circulation tanks are provided with a first liquid level gauge and a lower liquid port, and the first liquid level gauge is electrically connected to the lower liquid port of the circulation tank of the corresponding level.

3. The tail gas deamination system according to claim 1, characterized in that: The last stage circulation tank is provided with a feed pipe, the feed pipe is provided with a flow regulating valve, and the flow regulating valve is connected to the first liquid level meter signal of the last stage circulation tank.

4. The tail gas deamination system according to claim 1, characterized in that: The deamination reactor is provided with a second liquid level gauge, and the discharge port is electrically connected to the second liquid level gauge of the deamination reactor of the corresponding level.

5. The tail gas deamination system according to claim 1, characterized in that: A circulation pump is provided on the communicating pipe between the circulation tank and the feed inlet of the adjacent upper-stage deamination reactor.

6. The tail gas deamination system according to claim 5, characterized in that: It also includes a cooling mechanism, which is located on the communication pipe between the circulation pump and the feed inlet.

7. The tail gas deamination system according to claim 1, characterized in that: It also includes a gas-liquid separation mechanism, and the last-stage circulation tank is provided with an air outlet, which is communicated with the gas-liquid separation mechanism.

8. The tail gas deamination system according to claim 7, characterized in that: It also includes a hydroxyacetonitrile reactor, and the gas-liquid separation mechanism is provided with an exhaust port and a liquid discharge port, and the exhaust port is connected to the hydroxyacetonitrile reactor.

9. The tail gas deamination system according to claim 8, characterized in that: The liquid discharge port is connected to the last-stage circulation tank.

10. A carbon fiber production system, characterized in that: It comprises the tail gas deamination system as described in any one of claims 1 to 9.

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