A kind of recovery venting device and acetylene cracking reaction system

Abstract

The utility model discloses a kind of recovery venting air device and acetylene cracking reaction system, belong to acetylene cracking reaction equipment technical field, including recovery gas cabinet and gas ejector;The recovery gas cabinet is communicated with the pipeline between water scrubbing tower export and electric filter import by first pipeline, for recovering natural gas when accident venting;The first pipeline is communicated with fuel gas pipeline by second pipeline;Gas ejector is connected on the second pipeline;The gas ejector is used to suck, boost the natural gas recovered in recovery gas cabinet, and send back oxygen preheater and natural gas preheater bottom as preheating fuel.The utility model discloses recovery venting air device and acetylene cracking reaction system, by setting recovery venting air device in acetylene cracking reaction system, effective recovery and utilization of venting natural gas are realized, and then the energy saving and emission reduction of entire system are realized, and without newly adding high energy consumption power equipment, improve the annual comprehensive income of device.

Description

Technical Field

[0001] This utility model relates to the technical field of acetylene cracking reaction equipment, and is a device for recovering and releasing air and an acetylene cracking reaction system. Background Technology

[0002] Acetylene, as a basic chemical raw material, is mainly produced through two processes: the calcium carbide method and the natural gas partial oxidation method. Compared to the calcium carbide method, which suffers from high energy consumption, significant pollution, and low by-product utilization, the natural gas-to-acetylene process has become the mainstream production technology both domestically and internationally due to its advantages such as low energy consumption, good environmental performance, and full resource utilization. In the natural gas-to-acetylene process, the cracking step is the core link in acetylene production. The specific process is as follows: Raw natural gas and oxygen are heated separately by a natural gas preheater and an oxygen preheater, respectively, and then introduced radially and axially into the gas mixing section at the top of the cracking furnace for uniform mixing. After entering the reaction chamber of the cracking furnace, the mixed gas undergoes a flame reaction at 1300-1500℃, involving partial oxidation of natural gas and cracking of methane, producing acetylene and other products. To prevent acetylene decomposition and ensure yield, the gas after the reaction needs to be quenched to 85-90℃ by rapid cooling water to terminate the reaction. The quenched cracked gas is then cooled sequentially by a water scrubbing tower, passes through an electrofiltration unit to remove fine carbon black particles, and returns to the upper section of the scrubbing tower for further purification. Finally, it is cooled to 37℃ before being sent to the downstream compression process. However, the cracking reaction must be carried out under harsh conditions; pressure fluctuations, changes in oxygen ratio, and early ignition can easily lead to excessive oxygen content in the outlet gas of the cracking furnace. To prevent deflagration of excessive combustible gas in downstream processes (electro-filters or compressors), the system is equipped with a safety interlock mechanism: when the online analyzer detects excessive oxygen content, the oxygen feed valve and the emergency shut-off valve for pyrolysis gas to the electro-filter are closed, while the interlock switch valve of the pyrolysis gas flare pipeline is opened to guide the substandard gas into the flare for treatment; during this period, the natural gas feed valve remains open to replace the excessive gas in the system with natural gas and maintain the temperature of the pyrolysis furnace. After the oxygen injection conditions are met, the oxygen feed valve is restarted until the detected components are qualified, then the interlock switch valve to the flare is closed and the emergency shut-off valve is opened to resume production. However, this interlock venting process has revealed significant defects in actual operation: a single interlock venting cycle takes 10-12 minutes, and the total amount of natural gas vented is approximately 1500 standard cubic meters; the annual venting frequency of multiple existing units exceeds 100 times, resulting in an annual natural gas loss of over 150,000 standard cubic meters, causing huge economic losses. At the same time, the combustion of a large amount of natural gas emits a large amount of carbon dioxide, exacerbating carbon pollution and failing to meet the requirements of energy conservation, emission reduction, and sustainable development. In summary, existing acetylene cracking reactors suffer from frequent and large-volume accidental venting due to safety interlocks, resulting in significant waste of natural gas resources, severe economic losses, and substantial environmental pollution. Therefore, developing efficient venting recovery systems is a key technological innovation to address current operational challenges and achieve a win-win situation for both economic and environmental benefits. It holds significant practical and strategic value for promoting technological upgrading in the natural gas-to-acetylene industry. Utility Model Content

[0003] The purpose of this invention is to address the aforementioned shortcomings by providing a device for recovering vented natural gas and an acetylene cracking reaction system. This system effectively recovers and utilizes vented natural gas, thereby achieving energy conservation and emission reduction for the entire system. Furthermore, it eliminates the need for additional high-energy-consuming power equipment, thus increasing the overall annual revenue of the device. To achieve the above objectives, this invention provides the following technical solution: A venting recovery device includes a venting recovery tank and a gas injector. The venting recovery tank is connected to a pipeline between the outlet of a water scrubbing tower and the inlet of an electrostatic precipitator via a first pipeline, and is used to recover natural gas during an accidental venting. The first pipeline is connected to a fuel gas pipeline via a second pipeline. A gas injector is connected to the second pipeline. The gas injector is used to draw in and pressurize the natural gas recovered in the venting recovery tank, and send it back to the bottom of the oxygen preheater and the natural gas preheater via pipeline as preheating fuel.

[0004] Furthermore, the first pipeline is equipped with a first switching valve; the second pipeline is equipped with a second switching valve.

[0005] Furthermore, it also includes a third pipeline; the inlet and outlet of the third pipeline are both connected to the fuel gas pipeline; a gas injector is provided on the third pipeline, and the suction gas inlet of the gas injector is simultaneously connected to the second pipeline; a third switching valve is provided on the third pipeline at the power gas inlet end of the gas injector; a fourth switching valve is provided on the fuel gas pipeline between the inlet and outlet of the third pipeline.

[0006] Furthermore, it also includes a safety water seal chamber; the safety water seal chamber is connected to the pipeline between the water washing tower outlet and the flare via a fourth pipeline.

[0007] Furthermore, the recovered gas holder is a dry gas holder with a rubber sealing membrane inside; the volume of the recovered gas holder is 2000 cubic meters.

[0008] Furthermore, the recovered gas cabinet is equipped with a liquid level control instrument; the liquid level control instrument is connected to the control signals of the first switch valve, the second switch valve, the third switch valve and the fourth switch valve respectively.

[0009] An acetylene cracking reaction system includes an oxygen preheater, a natural gas preheater, a cracking furnace, a water scrubbing tower, an electrostatic precipitator, a flare, and the aforementioned air recovery and venting device. The outlets of the oxygen preheater and the natural gas preheater are respectively connected to the top of the cracking furnace via pipelines. The outlet of the cracking furnace is connected to the lower section inlet of the water scrubbing tower via a pipeline. The outlet of the lower section of the water scrubbing tower is connected to the inlet of the electrostatic precipitator via a pipeline. The outlet of the electrostatic precipitator is connected to the upper section inlet of the water scrubbing tower via a pipeline. The flare is connected to the pipeline between the lower section outlet of the water scrubbing tower and the inlet of the electrostatic precipitator via a fifth pipeline. The air recovery and venting device is connected to the lower section outlet of the water scrubbing tower via a first pipeline and to the outlet of the water scrubbing tower and the inlet of the flare via a fourth pipeline.

[0010] Furthermore, it also includes a fuel gas pipeline; the bottoms of the oxygen preheater and the natural gas preheater are respectively connected to the fuel gas pipeline that transports fuel natural gas; the air recovery and venting device is connected to the fuel gas pipeline through a second pipeline and a third pipeline.

[0011] Furthermore, a fifth switching valve is provided on the inlet pipe of the oxygen preheater; a sixth switching valve is provided on the inlet pipe of the natural gas preheater; a seventh switching valve is provided on the fifth pipe; and an eighth switching valve is provided on the inlet pipe of the electro-filter.

[0012] Furthermore, an online analyzer is installed on the pipeline at the lower outlet of the water washing tower; the online analyzer is connected to the control signals of the fifth switch valve, the seventh switch valve and the eighth switch valve respectively.

[0013] The beneficial effects of this utility model are: This utility model discloses a venting recovery device and an acetylene cracking reaction system, including a recovery gas holder and a gas injector. The recovery gas holder is connected to a pipeline between the outlet of a water scrubbing tower and the inlet of an electrostatic precipitator via a first pipeline, for recovering natural gas during accidental venting. The first pipeline is connected to a fuel gas pipeline via a second pipeline. A gas injector is connected to the second pipeline. The gas injector is used to draw in and pressurize the natural gas recovered in the recovery gas holder, and send it back to the bottom of the oxygen preheater and natural gas preheater as preheating fuel. This utility model discloses a venting recovery device and an acetylene cracking reaction system. By separately setting up a venting recovery device in the acetylene cracking reaction system, the effective recovery and utilization of vented natural gas is achieved, thereby realizing energy saving and emission reduction of the entire system, without the need for additional high-energy-consuming power equipment, thus improving the overall annual revenue of the device. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model; In the attached diagram: 1-Recovery gas holder, 2-Gas injector, 3-First pipeline, 4-First switching valve, 5-Second pipeline, 6-Second switching valve, 7-Third pipeline, 8-Third switching valve, 9-Fourth switching valve, 10-Safety water seal chamber, 11-Fourth pipeline, 12-Level control instrument, 13-Oxygen preheater, 14-Natural gas preheater, 15-Cracking furnace, 16-Water scrubbing tower, 17-Electrostatic filter, 18-Flame, 19-Fifth switching valve, 20-Sixth switching valve, 21-Seventh switching valve, 22-Eighth switching valve, 23-Online analyzer, 24-Fifth pipeline, 25-Flow regulating valve, 26-Pressure reducing valve. Detailed Implementation

[0015] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0016] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also mean including the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0017] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0018] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. The meaning of such spatial relative terms includes different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, then an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0019] The specific process of natural gas to acetylene is as follows: Raw natural gas and oxygen are heated separately by a natural gas preheater and an oxygen preheater, respectively, and then introduced radially and axially into the gas mixing section at the top of the cracking furnace for uniform mixing. After entering the reaction chamber of the cracking furnace, the mixed gas undergoes partial oxidation of natural gas and methane cracking in a flame reaction at 1300-1500℃, producing acetylene and other products. The reacted gas is then quenched to 85-90℃ by rapid cooling water to terminate the reaction. The quenched cracked gas is then sequentially cooled by a water scrubbing tower, passes through an electrofiltration unit to remove fine carbon black particles, and returns to the upper section of the scrubbing tower for further purification. Finally, it is cooled to 37℃ before being sent to the downstream compression process. When the online analyzer detects excessive oxygen content, the oxygen feed valve and the electrofiltration unit emergency shut-off valve are closed, while the interlock valve on the flare pipeline is opened to guide the substandard gas into the flare for treatment. During this period, the natural gas feed valve remains open to replace the excess gas in the system with natural gas and maintain the temperature. Once the conditions for oxygen injection are met, restart the oxygen feed valve until the tested components are qualified, then close the flare's interlock switch valve and open the emergency shut-off valve to resume production.

[0020] Example 1: See attached Figure 1 This utility model discloses a venting recovery device, mainly used for the recovery and utilization of natural gas during accidental venting in acetylene cracking reactions. (See attached diagram) Figure 1As shown in the dashed box, the part is the air recovery and venting device of this utility model, including a recovery gas holder 1, a gas injector 2, and a safety water seal chamber 10. The recovery gas holder 1 is a dry gas holder with a rubber sealing membrane inside. The recovery gas holder 1 is connected to the outlet of the water washing tower 16 and the inlet of the electrostatic precipitator 17 via a first pipe 3. A first switching valve 4 is installed on the first pipe 3. When an acetylene cracking reaction accident venting occurs and the natural gas in the vented air needs to be recovered, the first switching valve 4 is opened, allowing the natural gas in the vented air to flow into the recovery gas holder 1 through the first pipe 3 for storage. The volume of the recovery gas holder 1 can be set to 2000 cubic meters, and under normal circumstances, it can hold a total of 1500 standard cubic meters of accident gas released in a single event. A second pipe 5 is connected to the first pipe 3 at the inlet of the recovery gas holder 1. A second switch valve 6 and a gas injector 2 are installed on the second pipe 5. The second switch valve 6 is closer to the recovery gas holder 1 than the gas injector 2. The other end of the second pipe 5 is connected to a fuel gas pipeline for transporting fuel. The gas injector 2 can draw in and pressurize the natural gas recovered from the recovery gas holder 1 and send it into the fuel gas pipeline through the second pipe 5. Ultimately, it can be used to preheat fuel in the oxygen preheater 13 and the natural gas preheater 14. When the gas injector 2 draws in natural gas, the second switch valve 6 must be opened and the first switch valve 4 closed. This utility model discloses a venting recovery device and an acetylene cracking reaction system. By separately installing a venting recovery device in the acetylene cracking reaction system, the effective recovery and utilization of vented natural gas is achieved, thereby realizing energy saving and emission reduction of the entire system. Furthermore, no new high-energy-consuming power equipment is required, increasing the overall annual revenue of the device.

[0021] Specifically, the air recovery and venting device of this utility model also includes a third pipe 7. A third pipe 7 is provided between the second pipe 5 and the fuel gas pipe. The inlet and outlet of the third pipe 7 are both connected to the fuel gas pipe. A gas injector 2 is installed on the third pipe 7, and the suction gas inlet of the gas injector 2 is simultaneously connected to the second pipe 5. A third switch valve 8 is provided on the third pipe 7 at the power gas inlet end of the gas injector 2. A fourth switch valve 9 is provided on the fuel gas pipe between the inlet and outlet of the third pipe 7. When the gas injector 2 draws in and pressurizes the natural gas in the gas holder 1, because the natural gas pressure in the gas holder 1 is relatively low, while the natural gas pressure originally transported in the fuel gas pipe is relatively high, the fourth switch valve 9 can be closed, and the third switch valve 8 and the second switch valve 6 can be opened. The natural gas from the fuel gas pipe flows through the third pipe 7 and is powered by the gas injector 2. The gas injector 2 draws in and pressurizes the natural gas in the gas holder 1, thereby reducing the natural gas pressure in the fuel gas pipe and increasing the natural gas pressure in the gas holder 1, so that the natural gas injected from the gas injector 2 meets the pressure requirements of downstream users. The air recovery and venting device of this invention can use the natural gas pressure of the original fuel gas pipeline as a power source to pressurize and utilize the recovered natural gas, avoiding the need to add a gas compressor and reducing equipment investment.

[0022] Specifically, the air recovery and venting device of this utility model also includes a safety water seal chamber 10. The safety water seal chamber 10 is connected to the pipeline between the outlet of the water scrubbing tower 16 and the flare 18 via a fourth pipeline 11. The inlet of the fourth pipeline 11 is connected to the pipeline between the outlet of the water scrubbing tower 16 and the inlet of the electrostatic precipitator 17, located between the first pipeline 3 and the fifth pipeline 24. The outlet of the fourth pipeline 11 is connected to the fifth pipeline 24. A liquid level control instrument 12 is provided in the gas recovery holder 1. The liquid level control instrument 12 is connected to the control signals of the first switch valve 4 and the second switch valve 6. The liquid level control instrument 12 monitors the volume of natural gas entering the gas recovery holder 1 by the rise and fall of the rubber sealing membrane in the gas recovery holder 1 as the natural gas enters. When the total amount of emergency venting increases due to other unpredictable reasons, the liquid level control instrument 12 monitors the liquid level in the gas recovery holder 1 and, when it rises to the set value, interlocks and closes the first switch valve 4. As the amount of emergency vented natural gas increases, it can break through the safety water seal chamber 10 and be discharged from the outlet of the safety water seal chamber 10 through the fourth pipeline 11 into the flare 18, thus ensuring the safety of the gas recovery holder 1.

[0023] Example 2: See attached Figure 1 An acetylene cracking reaction system includes an oxygen preheater 13, a natural gas preheater 14, a cracking furnace 15, a water scrubbing tower 16, an electrostatic precipitator 17, a flare 18, and the air recovery and venting device described in Example 1. (See attached diagram) Figure 1As shown, the bottoms of the oxygen preheater 13 and the natural gas preheater 14 are connected to fuel gas pipelines, respectively. Fuel gas is supplied to the oxygen preheater 13 and the natural gas preheater 14 through the fuel gas pipelines to preheat the oxygen in the oxygen preheater 13 and the natural gas in the natural gas preheater 14. The outlets of the oxygen preheater 13 and the natural gas preheater 14 are connected to the top of the cracking furnace 15 through pipelines. When setting this pipeline, the preheated oxygen can be introduced into the cracking furnace 15 horizontally and the preheated natural gas can be introduced into the cracking furnace 15 vertically, or the preheated oxygen can be introduced into the cracking furnace 15 vertically and the preheated natural gas can be introduced into the cracking furnace 15 horizontally, so that the oxygen and natural gas enter the mixing section at the top of the cracking furnace 15 for uniform mixing, and then enter the reaction chamber of the cracking furnace 15 for reaction. The outlet of the cracking furnace 15 is connected to the lower inlet of the water washing tower 16 via a pipeline. The outlet of the lower section of the water washing tower 16 is connected to the inlet of the electrostatic precipitator 17 via a pipeline. The outlet of the electrostatic precipitator 17 is connected to the upper inlet of the water washing tower 16 via a pipeline. The gas reacting in the reaction chamber of the cracking furnace 15 is quenched by rapid cooling water and then enters the lower section of the water washing tower 16 for further cooling. In the electrostatic precipitator 17, fine carbon black particles are removed from the gas. Finally, the gas returns to the upper section of the washing tower for further washing and cooling. The final gas temperature drops to 37°C, and most of the carbon black is removed. It is then sent downstream from the top of the water washing tower 16 for compression. This is a detailed description of the natural gas to acetylene process. Additionally, a flow regulating valve 25 is installed on the fuel gas pipeline connected to the bottom of the oxygen preheater 13 and the natural gas preheater 14.

[0024] Specifically, to prevent combustible gases with excessive oxygen content from deflagrifying in downstream processes (electro-filters or compressors), the acetylene cracking reaction system also includes a flare 18 for handling vented gases during accident venting and a vent recovery device for recovering and utilizing natural gas from the vented gas, as described in Example 1. The flare 18 is connected to the pipeline between the lower outlet of the water scrubbing tower 16 and the inlet of the electro-filter 17 via a fifth pipeline 24, and a seventh switching valve 21 is installed on the fifth pipeline 24. The air recovery and venting device includes a recovery gas holder 1, a gas injector 2, and a safety water seal chamber 10. The recovery gas holder 1 is connected to the outlet of the water washing tower 16 and the inlet of the electrostatic precipitator 17 via a first pipe 3. A first switch valve 4 is installed on the first pipe 3. A second pipe 5 is connected to the first pipe 3 at the inlet of the recovery gas holder 1. A second switch valve 6 is installed on the second pipe 5. The other end of the second pipe 5 is connected to a third pipe 7. The inlet and outlet of the third pipe 7 are both connected to a fuel gas pipeline. A gas injector 2 is installed at the connection between the second pipe 5 and the third pipe 7. The two inlets of the gas injector 2 are connected to the second pipe 5 and the third pipe 7, respectively. A third switch valve 8 is installed on the third pipe 7 at the power gas inlet end of the gas injector 2. A fourth switch valve 9 is installed on the fuel gas pipeline between the inlet and outlet of the third pipe 7. The safety water seal chamber 10 is connected to the pipeline between the outlet of the water scrubbing tower 16 and the flare 18 via the fourth pipeline 11. The inlet of the fourth pipeline 11 is connected to the pipeline between the outlet of the water scrubbing tower 16 and the inlet of the electrostatic precipitator 17, located between the first pipeline 3 and the fifth pipeline 24. The outlet of the fourth pipeline 11 is connected to the fifth pipeline 24. In addition, an online analyzer 23 is installed on the pipeline at the lower outlet of the water scrubbing tower 16. The online analyzer 23 is connected to the control signals of the fifth switch valve 19 and the seventh switch valve 21 installed on the pipeline at the inlet of the oxygen preheater 13, and the eighth switch valve 22 installed on the pipeline at the inlet of the electrostatic precipitator 17.

[0025] The specific working process of this acetylene cracking reaction system during accidental venting is as follows: When the online analyzer 23 detects that the oxygen content of the gas flowing through the corresponding pipeline exceeds the standard, it interlocks and closes the fifth switch valve 19, stopping the supply of oxygen to the system. Simultaneously, it closes the eighth switch valve 22 and opens the seventh switch valve 21. The accident gas with excessive oxygen content will enter the flare 18 for processing. At this time, the sixth switch valve 20 remains open, continuously supplying natural gas to the reaction system to completely replace the substandard gas. After approximately 1-2 minutes, the seventh switch valve 21 is closed while the first switch valve 4 is opened, and the subsequent accident gas enters the recovery gas holder 1 for storage. Once the oxygen supply conditions are met, the fifth switch valve 19 is restarted and the first switch valve 4 is closed. The oxygen undergoes a partial oxidation reaction, and the seventh switch valve 21 is opened. The substandard gas at this time re-enters the flare 18 for processing until the online analyzer 23 detects that the composition of the gas flowing through the corresponding pipeline is within acceptable limits. Then, the seventh switch valve 21 is closed while the eighth switch valve 22 is opened, and the reaction system returns to normal operation. This ensures that the recovery gas holder 1 recovers the intermediate emitted natural gas during the venting process, facilitating its safe reuse later. When the natural gas in the recovery gas holder 1 needs to be utilized, the fourth switch valve 9 on the fuel gas pipeline is closed while the third switch valve 8 and the second switch valve 6 are opened. At this time, the first switch valve 4 is closed. The natural gas from the fuel gas pipeline flows through the third pipeline 7 and passes through the gas injector 2 as a power source. The gas injector 2 draws in and pressurizes the low-pressure natural gas in the recovery gas holder 1. The pressure of the mixed natural gas ejected by the gas injector 2 meets the needs of downstream users and is sent into the fuel gas pipeline. Finally, it enters the bottom of the oxygen preheater 13 and the natural gas preheater 14 as preheating fuel, thus achieving effective recovery and utilization of the natural gas in the recovery gas holder 1. In addition, a pressure reducing valve 26 is installed on the fuel gas pipeline. Since the pressure of the fuel natural gas entering the fuel gas pipeline from the fuel natural gas source is relatively high, it is often necessary to install a pressure reducing valve 26 to reduce its pressure. When the natural gas in the recovery gas holder 1 is not being utilized, the fourth switch valve 9 is opened, and the natural gas from the fuel natural gas source enters the fuel gas pipeline, is reduced in pressure, and is sent to the bottom of the oxygen preheater 13 and the natural gas preheater 14. The pressure of the natural gas after pressure reduction is basically the same as the pressure at the outlet of the gas injector.

[0026] When the total amount of emissions increases due to other unforeseen reasons, and the liquid level control instrument 12 detects that the liquid level of the recovery gas tank 1 has risen to the set value, the first switch valve 4 is interlocked and closed. As the amount of natural gas released in the accident increases, it can break through the safety water seal chamber 10 and be discharged from the outlet of the safety water seal chamber 10 through the fourth pipeline 11 into the flare 18 to ensure the safety of the recovery gas tank 1.

[0027] This utility model discloses an acetylene cracking reaction system that recovers vented air during accidental venting from a recovery gas holder. Utilizing natural gas from the fuel gas pipeline as a power source, the system uses a gas injector to draw in the recovered natural gas from the gas holder, pressurizes it, and then uses it to preheat fuel in oxygen and natural gas preheaters. The entire process requires no additional high-energy-consuming power equipment, achieving efficient recovery and resource utilization of accidental vented air. This promotes the development of vented air recovery technology in chemical plants while driving the green transformation of the acetylene industry. Its application prospects are broad, its economies of scale are significant, and it offers both environmental and economic benefits. It is a core technology for driving the acetylene industry towards a low-carbon, high-efficiency, and sustainable transformation, and has the potential for large-scale application.

[0028] All technical features in this embodiment can be freely combined according to actual needs. The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model. Technologies, shapes, and structural parts not described in detail in this utility model are all known technologies.

[0029] The above embodiments are preferred implementations of this utility model. In addition, other implementations are also included. Any obvious substitutions without departing from the concept of this technical solution are within the protection scope of this utility model.

Claims

1. An air recovery and venting device, characterized in that: It includes a gas recovery tank (1) and a gas injector (2); the gas recovery tank (1) is connected to the outlet of the water washing tower (16) and the inlet of the electric filter (17) through a first pipe (3) for recovering natural gas during accident venting; the first pipe (3) is connected to the fuel gas pipeline through a second pipe (5); the second pipe (5) is connected to the gas injector (2); the gas injector (2) is used to draw and pressurize the natural gas recovered in the gas recovery tank (1) and send it back to the bottom of the oxygen preheater (13) and the natural gas preheater (14) through the pipeline as preheating fuel.

2. The air recovery and venting device according to claim 1, characterized in that: The first pipe (3) is provided with a first switch valve (4); the second pipe (5) is provided with a second switch valve (6).

3. The air recovery and venting device according to claim 2, characterized in that: It also includes a third pipe (7); the inlet and outlet of the third pipe (7) are both connected to the fuel gas pipe; a gas injector (2) is provided on the third pipe (7), and the suction gas inlet of the gas injector (2) is simultaneously connected to the second pipe (5); a third switch valve (8) is provided on the third pipe (7) at the power gas inlet end of the gas injector (2); a fourth switch valve (9) is provided on the fuel gas pipe between the inlet and outlet of the third pipe (7).

4. The air recovery and venting device according to claim 3, characterized in that: It also includes a safety water seal chamber (10); the safety water seal chamber (10) is connected to the outlet of the water washing tower (16) and the flare (18) via a fourth pipe (11).

5. The air recovery and venting device according to claim 4, characterized in that: The gas recovery unit (1) is a dry gas unit with a rubber sealing membrane inside; the volume of the gas recovery unit (1) is 2000 cubic meters.

6. The air recovery and venting device according to claim 5, characterized in that: The recovered gas tank (1) is equipped with a liquid level control instrument (12); the liquid level control instrument (12) is connected to the control signals of the first switch valve (4), the second switch valve (6), the third switch valve (8) and the fourth switch valve (9).

7. An acetylene cracking reaction system, characterized in that: The system includes an oxygen preheater (13), a natural gas preheater (14), a pyrolysis furnace (15), a water scrubbing tower (16), an electric filter (17), a flare (18), and an air recovery device as described in claim 6; the outlet of the oxygen preheater (13) and the outlet of the natural gas preheater (14) are respectively connected to the top of the pyrolysis furnace (15) via pipelines; the outlet of the pyrolysis furnace (15) is connected to the lower inlet of the water scrubbing tower (16) via a pipeline; the lower outlet of the water scrubbing tower (16) is connected to the inlet of the electric filter (17) via a pipeline; the outlet of the electric filter (17) is connected to the upper inlet of the water scrubbing tower (16) via a pipeline; the flare (18) is connected to the pipeline between the lower outlet of the water scrubbing tower (16) and the inlet of the electric filter (17) via a fifth pipeline (24); the air recovery device is connected to the outlet of the water scrubbing tower (16) via a first pipeline (3), and to the outlet of the water scrubbing tower (16) and the inlet of the flare (18) via a fourth pipeline (11).

8. The acetylene cracking reaction system according to claim 7, characterized in that: It also includes a fuel gas pipeline; the bottoms of the oxygen preheater (13) and the natural gas preheater (14) are respectively connected to the fuel gas pipeline that transports fuel natural gas; the air recovery and venting device is connected to the fuel gas pipeline through the second pipeline (5) and the third pipeline (7).

9. The acetylene cracking reaction system according to claim 8, characterized in that: The oxygen preheater (13) is provided with a fifth switch valve (19) on the inlet pipe; the natural gas preheater (14) is provided with a sixth switch valve (20) on the inlet pipe; the fifth pipe (24) is provided with a seventh switch valve (21); and the electric filter (17) is provided with an eighth switch valve (22) on the inlet pipe.

10. The acetylene cracking reaction system according to claim 9, characterized in that: An online analyzer (23) is installed on the pipeline at the lower outlet of the water washing tower (16); the online analyzer (23) is connected to the control signals of the fifth switch valve (19), the seventh switch valve (21) and the eighth switch valve (22) respectively.

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