Tail gas recovery system

Abstract

The invention discloses a tail gas recovery system which comprises a pretreatment system, a membrane separation system, a gas mixing tank and an adjusting system, the pretreatment system is used for performing impurity removal and pressurization treatment on tail gas; the membrane separation system comprises multi-stage connected membrane separation assemblies, each membrane separation assembly comprises a shell and a membrane pipe arranged in the shell, a tail gas input end is arranged on the side face of the shell, the side face of the opening end of each membrane pipe is in sealed connection with the inner side face of the shell, and a permeated gas exhaust end correspondingly communicated with the opening end of each membrane pipe is arranged at one end of the shell. The plurality of permeated gas discharge ends are connected with an external permeated gas recovery system, and the other end of the shell is provided with a pressure control valve for discharging impermeable gas; the gas mixing tank is connected with the pressure control valve of the last-stage membrane separation assembly; the adjusting system is connected with the gas mixing tank and used for monitoring and adjusting the gas proportion in the gas mixing tank. According to the method, available components in the tail gas can be recycled for continuous use, so that certain economic benefits can be generated, the production cost can be reduced, and the hidden danger of environmental protection can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of tail gas treatment, and particularly relates to a tail gas recovery system. Background Art

[0002] In the industrial field, acetylene is used as a basic raw material, and through a thermal cracking process, the aim is to obtain high-quality pyrolytic carbon and deposit it on the surface of the target device. However, in terms of the current state of technological development, the effective utilization rate of acetylene is still relatively low. Specifically, most of the tail gas generated after the thermal cracking reaction of acetylene is directly discharged into the atmosphere, or is treated by combustion and then discharged. This approach not only results in significant waste of resources, that is, the unutilized acetylene components are wasted, but also directly increases the use cost of acetylene as a production raw material. In addition, if the acetylene thermal cracking tail gas is directly discharged without proper treatment, it may pose potential environmental protection risks and pose a certain threat to the ecological environment.

[0003] The current commonly adopted treatment strategies in the industry are to discharge after combustion treatment or directly discharge into the external environment. These traditional methods not only have low economic benefits and cannot effectively recover valuable components in the tail gas, but also may have obvious pollution impacts on the surrounding environment, which does not conform to the current green and sustainable development concept. Summary of the Invention

[0004] Aiming at the above existing problems, the purpose of the present invention is to provide a tail gas recovery system that can recover and reuse the available components in the tail gas, which can not only generate certain economic benefits, reduce production costs, but also solve environmental protection hidden dangers.

[0005] The technical solution of the present invention is: a tail gas recovery system, comprising:

[0006] A pretreatment system for removing impurities and pressurizing the tail gas;

[0007] A membrane separation system, the membrane separation system includes a plurality of membrane separation components connected in series. Each membrane separation component includes a housing and a membrane tube disposed inside the housing. The side of the housing is provided with a tail gas input end. The membrane tube is a hollow tube with one end closed and the other end open. The side of the open end of the membrane tube is hermetically connected to the inner side of the housing. One end of the housing is provided with a permeate gas discharge end corresponding to and communicating with the open end of the membrane tube. The other end of the housing is provided with a pressure control valve for discharging non-permeate gas. The tail gas input end of the first-stage membrane separation component is connected to the pretreatment system for receiving the tail gas treated by the pretreatment system, and the pressure control valve of the upper-stage membrane separation component is connected to the tail gas input end of the lower-stage membrane separation component;

[0008] The gas mixing tank is connected to the pressure control valve of the last-stage membrane separation module and is used to receive the separated gas;

[0009] The regulation system is connected to the gas mixing tank and is used to monitor and regulate the gas ratio in the gas mixing tank.

[0010] Further, the pretreatment system includes:

[0011] The filter element is used to receive the tail gas discharged from the workshop and filter and remove the impurities in the tail gas;

[0012] The compressor is connected to the output end of the filter element and is used to pressurize the filtered tail gas and then introduce it into the membrane separation system.

[0013] Further, the membrane tube selects a gas separation membrane with 400 - 800 meshes, and the material of the gas separation membrane is polyimide.

[0014] Further, the regulation system includes:

[0015] The gas component monitoring module is connected between the pressure control valve of the last-stage membrane separation module and the gas mixing tank and is used to monitor the gas component ratio of the gas input into the gas mixing tank through the pressure control valve;

[0016] A plurality of supplementary gas pipelines are respectively connected to the gas mixing tank through gas flow valves, and the gas flow valves are respectively connected to the gas component monitoring module and are used to control the supplementary gas ratio of the supplementary gas pipelines according to the gas component ratio of the gas input into the gas mixing tank through the pressure control valve.

[0017] Further, a plurality of the permeate gas discharge ends are all connected to an external permeate gas recovery system.

[0018] The recovery method of the above-mentioned tail gas recovery system includes the following steps:

[0019] The tail gas discharged from the workshop first passes through the filter element to filter and remove the particulate matter and dust impurities existing in the tail gas, and then the tail gas enters the compressor for pressurization. After the pressure of the tail gas increases, it is transmitted to the membrane separation system;

[0020] The tail gas enters the interior of the housing through the tail gas input end of the membrane separation module. Under the action of pressure, there is a pressure difference between the inner and outer sides of the membrane tube. The gas molecules with a fast dissolution and diffusion rate pass through the side of the membrane tube and enter the interior of the membrane tube to become permeate gas, which is output to the external permeate gas recovery system for reuse through the permeate gas discharge end. The gas molecules that cannot pass through the membrane tube enter the next-stage membrane separation module through the pressure control valve for further separation;

[0021] The separated gas enters the mixing gas tank after passing through the gas component monitoring assembly. The gas component monitoring assembly monitors the component ratio of the gas entering the mixing gas tank, and then controls the gas flow valve to open the corresponding supplementary gas pipeline to supplement gas into the mixing gas tank at a set ratio, so that the gas component ratio in the mixing gas tank reaches the set ratio.

[0022] The gas in the mixing gas tank is transported to the workshop through a pipeline for continued use.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: A tail gas recovery system provided by the present invention gives the tail gas appropriate pressure through a compressor, so that the difference in the separation driving force of the partial pressures of each component gas in the tail gas in the membrane separation assembly is the largest, and each gas component can be better separated. The tail gas is repeatedly passed through several stages of membrane separation assemblies, and high-purity non-permeating gas can be obtained and transported into the mixing gas tank. Then, after being supplemented through multiple supplementary gas pipelines, a mixed gas with the proportion required by the process production can be obtained and transported to the workshop for continued use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the overall structural schematic diagram of the present invention;

[0025] Figure 2 is the structural schematic diagram of the membrane separation assembly of the present invention.

[0026] Among them, 1. Pretreatment system; 11. Filter element; 12. Compressor; 2. Membrane separation system; 21. Membrane separation assembly; 211. Shell; 212. Membrane tube; 213. Tail gas input end; 214. Permeating gas discharge end; 215. Pressure control valve; 3. Mixing gas tank; 4. Adjustment system; 41. Gas component monitoring assembly; 42. Supplementary gas pipeline; 43. Gas flow valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following combines the attached Figure 1 to the attached Figure 2 , and describes the specific embodiments of the present invention in detail. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0028] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features; in the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0029] It should be noted that the circuit connections involved in the present invention all adopt conventional circuit connection methods and do not involve any innovation.

[0030] Example: As Figure 1 shown, an exhaust gas recovery system includes a pretreatment system 1, a membrane separation system 2, a gas mixing tank 3, and a regulation system 4. Among them:

[0031] The pretreatment system 1 is used for removing impurities and pressurizing the exhaust gas. The pretreatment system 1 includes a filter element 11 and a compressor 12; the filter element 11 is used for receiving the exhaust gas discharged from the workshop and filtering and removing the impurities in the exhaust gas; the compressor 12 is connected to the output end of the filter element 11 and is used for pressurizing the filtered exhaust gas and introducing it into the membrane separation system 2;

[0032] The membrane separation system 2 includes a plurality of membrane separation components 21 connected in series. As Figure 2 shown, each membrane separation component 21 includes a housing 211 and a membrane tube 212 disposed inside the housing 211. The side of the housing 211 is provided with an exhaust gas input end 213. The membrane tube 212 is a hollow tube with one end closed and the other end open. The open end side of the membrane tube 212 is hermetically connected to the inner side of the housing 211. One end of the housing 211 is provided with a permeate gas discharge end 214 corresponding to and communicating with the open end of the membrane tube 212. A plurality of permeate gas discharge ends 214 are all connected to an external permeate gas recovery system. The other end of the housing 211 is provided with a pressure control valve 215 for discharging non-permeate gas. The exhaust gas input end 213 of the first-stage membrane separation component 21 is connected to the pretreatment system 1 for receiving the exhaust gas treated by the pretreatment system 1, and the pressure control valve 215 of the upper-stage membrane separation component 21 is connected to the exhaust gas input end 213 of the lower-stage membrane separation component 21. The membrane tube 212 selects a gas separation membrane with 400 meshes, and the gas separation membrane material is polyimide;

[0033] The gas mixing tank 3 is connected to the pressure control valve 215 of the last-stage membrane separation component 21 for receiving the separated gas;

[0034] The adjustment system 4 is connected to the gas mixing tank 3 and is used to monitor and adjust the gas ratio in the gas mixing tank 3. The adjustment system 4 includes a gas component monitoring assembly 41 and a plurality of supplementary gas pipelines 42. The gas component monitoring assembly 41 is connected between the pressure control valve 215 of the last-stage membrane separation assembly 21 and the gas mixing tank 3 and is used to monitor the gas component ratio of the gas input into the gas mixing tank 3 through the pressure control valve 215. The plurality of supplementary gas pipelines 42 are respectively connected to the gas mixing tank 3 through gas flow valves 43, and the gas flow valves 43 are respectively connected to the gas component monitoring assembly 41 and are used to control the supplementary gas ratio of the supplementary gas pipelines 42 according to the gas component ratio of the gas input into the gas mixing tank 3 by the pressure control valve 215.

[0035] The recovery method of a tail gas recovery system provided by the above embodiment includes the following steps:

[0036] The tail gas discharged from the workshop first passes through the filter element 11 to filter and remove the particulate matter and dust impurities existing in the tail gas, and then the tail gas enters the compressor 12 for pressurization. After the pressure of the tail gas increases, it is transmitted to the membrane separation system 2;

[0037] The tail gas enters the interior of the housing 211 through the tail gas input end 213 of the membrane separation assembly 21. Under the action of pressure, there is a pressure difference between the inner and outer sides of the membrane tube 212. The gas molecules with a fast dissolution and diffusion rate pass through the side of the membrane tube 212 and enter the interior of the membrane tube 212 to become permeate gas, which is output to the external permeate gas recovery system for reuse through the permeate gas discharge end 214. The gas molecules that cannot pass through the membrane tube 212 enter the next-stage membrane separation assembly 21 through the pressure control valve 215 for further separation;

[0038] The separated gas enters the gas mixing tank 3 after passing through the gas component monitoring assembly 41. The gas component monitoring assembly 41 monitors the component ratio of the gas entering the gas mixing tank 3, and then controls the gas flow valve 43 to open the corresponding supplementary gas pipeline 42 to supplement gas into the gas mixing tank 3 at a set ratio so that the gas component ratio in the gas mixing tank 3 reaches the set ratio;

[0039] The gas in the gas mixing tank 3 is transported to the workshop through a pipeline for continued use.

[0040] No special specifications are made for the specific models of the above electronic components, and ordinary commercially available products can be selected as long as they can meet the usage requirements of the present invention.

[0041] The above specific embodiments have further detailed the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and do not limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A tail gas recovery system, characterized in that: include: A pretreatment system (1) is used to remove impurities and pressurize the tail gas; A membrane separation system (2), the membrane separation system (2) comprising a multi-stage connected membrane separation assembly (21), each of the membrane separation assemblies (21) comprising an outer shell (211) and a membrane tube (212) arranged inside the outer shell (211), a tail gas input end (213) being arranged on the side of the outer shell (211), the membrane tube (212) being a hollow tube with one end closed and the other end open, the side of the open end of the membrane tube (212) being sealedly connected to the inner side of the outer shell (211), the outer shell (211) 1) a permeate gas discharge end (214) corresponding to the open end of the membrane tube (212) is provided at one end, a pressure control valve (215) for discharging non-permeate gas is provided at the other end of the housing (211), a tail gas input end (213) of the first-stage membrane separation component (21) is connected to the pretreatment system (1) for receiving the tail gas treated by the pretreatment system (1), and the pressure control valve (215) of the upper-stage membrane separation component (21) is connected to the tail gas input end (213) of the lower-stage membrane separation component (21); A gas mixing tank (3) connected to the pressure control valve (215) of the last-stage membrane separation assembly (21) for receiving the separated gas; The regulating system (4) is connected to the gas mixing tank (3) and is used to monitor and regulate the gas ratio in the gas mixing tank (3).

2. The tail gas recovery system according to claim 1, characterized in that: The pretreatment system (1) comprises: The filter element (11) is used to receive the exhaust gas discharged from the workshop and filter and remove impurities in the exhaust gas; The compressor (12) is connected to the output end of the filter element (11) and is used to pressurize the filtered tail gas before passing it into the membrane separation system (2).

3. The tail gas recovery system according to claim 1, characterized in that: The membrane tube (212) is a gas separation membrane with a mesh size of 400-800, and the material of the gas separation membrane is polyimide.

4. The tail gas recovery system according to claim 2, characterized in that: The regulating system (4) comprises: A gas component monitoring component (41) is connected between the pressure control valve (215) of the last-stage membrane separation component (21) and the gas mixing tank (3) and is used to monitor the proportion of gas components input into the gas mixing tank (3) through the pressure control valve (215); A plurality of supplementary gas pipelines (42) are respectively connected to the gas mixing tank (3) via gas flow valves (43); the gas flow valves (43) are respectively connected to the gas component monitoring components (41) and are used to control the supplementary gas ratio of the supplementary gas pipeline (42) according to the gas component ratio of the gas mixing tank (3) introduced into the gas mixing tank via the pressure control valve (215).

5. A tail gas recovery system as claimed in claim 4, characterized in that: The plurality of permeate gas discharge ends (214) are all connected to an external permeate gas recovery system.

6. A recovery method of a tail gas recovery system as claimed in claim 5, characterized in that: The following steps are involved: The exhaust gas discharged from the workshop first passes through the filter element (11) to filter and remove particulate matter and dust impurities in the exhaust gas, and then the exhaust gas enters the compressor (12) for pressurization. After the pressure of the exhaust gas is increased, it is transmitted to the membrane separation system (2); The tail gas enters the housing (211) through the tail gas input end (213) of the membrane separation component (21). Under the action of pressure, there is a pressure difference between the inside and the outside of the membrane tube (212). Gas molecules with a fast dissolution and diffusion rate pass through the side of the membrane tube (212) and enter the inside of the membrane tube (212) to become permeate gas, which is output to an external permeate gas recovery system for reuse through the permeate gas discharge end (214). Gas molecules that cannot pass through the membrane tube (212) enter the next-level membrane separation component (21) through the pressure control valve (215) for further separation. The separated gas passes through the gas component monitoring component (41) and enters the gas mixing tank (3). The gas component monitoring component (41) monitors the component ratio of the gas entering the gas mixing tank (3), and then controls the gas flow valve (43) to open the corresponding supplementary gas pipeline (42), so as to supplement the gas into the gas mixing tank (3) at a set ratio, so that the gas component ratio in the gas mixing tank (3) reaches the set ratio; The gas in the gas mixing tank (3) is transported to the workshop through a pipeline for further use.

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