Acetylene cracking furnace mixing distributor and cracking furnace

Abstract

The invention discloses an acetylene cracking furnace mixing distributor and a cracking furnace. The acetylene cracking furnace mixing distributor comprises a central cylinder and an outer cylinder, the center cylinder is arranged in the outer cylinder, the outer cylinder and the center cylinder are matched to form a gas mixing annular space with a narrow radial diffusion path, and an initial mixing area, a flow development area and a diffusion mixing area are sequentially formed from top to bottom; a natural gas inlet assembly is arranged at the upper end of the outer cylinder, and an oxygen inlet assembly is arranged on the periphery. Natural gas and oxygen enter the gas mixing annular space from the natural gas inlet assembly and the oxygen inlet assembly correspondingly and are fully mixed through the initial mixing area, the flowing development area and the diffusion mixing area. The mixing distributor of the acetylene cracking furnace realizes efficient mixing of natural gas and oxygen, and is simple in structure, small in overall size and easy to manufacture and maintain.

Description

Technical Field

[0001] This invention relates to the field of acetylene cracking equipment technology, specifically to an acetylene cracking furnace mixing distributor and cracking furnace. Background Technology

[0002] Acetylene, as an important basic chemical raw material, plays an irreplaceable role in organic synthesis, materials manufacturing, and other fields. The partial oxidation of natural gas, due to its wide availability of raw materials and high reaction efficiency, has become the mainstream process for industrial acetylene production. The acetylene cracking furnace, as the core and critical equipment of this process, directly determines the stability of the production process, product yield, and energy consumption. In the acetylene cracking furnace's workflow, preheated high-temperature natural gas and oxygen must be premixed in a mixer at the top of the furnace before entering the furnace for reaction. Therefore, the mixing effect of the mixer becomes a core factor affecting the entire production system—a uniform gas-phase concentration and velocity distribution is crucial for ensuring continuous and stable operation, complete reaction, and improved acetylene yield, while effectively avoiding increased energy consumption caused by local reaction imbalances.

[0003] Currently, there are two main structural forms of acetylene cracking furnace mixers widely used in the industrial field: the upper premixed and Venturi structure and the central cylinder and diffuser section structure. However, both structures have significant technical defects, making it difficult to simultaneously meet the actual production requirements of efficient mixing and compact structure. For the upper premixed and Venturi structure mixer, the core design idea is to achieve airflow transition and buffering by extending the equipment length, thereby achieving a preliminary mixing effect. Although this structure can ensure mixing uniformity to a certain extent, the overall length of the equipment is nearly twice that of the central cylinder and diffuser section structure. The excessively long structural design not only increases the material cost and processing difficulty of the equipment manufacturing, but also places higher demands on the installation space. At the same time, the extended airflow path in the mixer leads to increased system resistance, indirectly increasing production energy consumption. Moreover, during long-term operation, the excessively long flow channel is prone to forming local stagnant zones, increasing the risk of early ignition and affecting the continuous and stable operation of the equipment. The central cylinder and diffuser section structure mixer adopts a more compact design, effectively shortening the equipment size and reducing installation and manufacturing costs. However, its structural design failed to fully consider the flow characteristics of natural gas and oxygen. During the mixing process, it was difficult to achieve a uniform distribution of concentration and velocity of the two gases quickly, resulting in an unsatisfactory mixing effect. This directly led to a low yield of acetylene products and a high frequency of early ignition, which could not meet the requirements of industrial production for capacity and efficiency.

[0004] In summary, both existing mixers have certain limitations. Developing a mixing distributor for acetylene cracking furnaces that can achieve efficient mixing in a short residence time, while also possessing advantages such as simple structure, compact size, and convenient manufacturing and maintenance, has become an urgent technical problem to be solved in the field of natural gas chemical industry. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned shortcomings by providing an acetylene cracking furnace mixing distributor and cracking furnace, achieving efficient mixing of natural gas and oxygen, with a simple structure, small overall size, and ease of manufacturing and maintenance. To achieve the above objective, this invention provides the following technical solution: An acetylene cracking furnace mixing distributor includes a central cylinder and an outer cylinder. The central cylinder is disposed inside the outer cylinder, and the outer cylinder and the central cylinder cooperate to form a radially diffused gas mixing annulus, which sequentially forms an initial mixing zone, a flow development zone, and a diffusion mixing zone from top to bottom. The upper end of the outer cylinder is provided with a natural gas inlet assembly, and the outer periphery is provided with an oxygen inlet assembly. Natural gas and oxygen enter the gas mixing annulus from the natural gas inlet assembly and the oxygen inlet assembly, respectively, and are fully mixed through the initial mixing zone, the flow development zone, and the diffusion mixing zone.

[0006] Furthermore, the oxygen inlet assembly includes a distribution cylinder; the upper part of the outer cylinder is provided with a distribution cylinder circumferentially around the outer cylinder; the distribution cylinder is provided with an oxygen inlet; the portion of the outer cylinder surrounded by the distribution cylinder is provided with oxygen distribution holes; the total cross-sectional area of ​​the oxygen distribution holes is smaller than the cross-sectional area of ​​the gas mixing annular gap.

[0007] Furthermore, the oxygen inlet assembly also includes a baffle; the baffle is arranged around the oxygen distribution hole along the circumference of the outer cylinder and is located inside the distribution cylinder; the upper and lower sides of the baffle are provided with openings for oxygen to enter.

[0008] Furthermore, the oxygen inlet of the distribution cylinder is provided with multiple flow dividers; the flow dividers are arranged longitudinally along the oxygen inlet.

[0009] Furthermore, the oxygen distribution holes are smoothly transitioned with rounded corners on both sides.

[0010] Furthermore, the natural gas inlet assembly includes a cone and a connecting pipe for guiding flow; the connecting pipe has a connecting flange at the top and is connected to the upper inlet of the outer cylinder at the bottom; the connecting pipe is a reducer structure or a straight cylindrical structure; the top of the central cylinder has a cone; the cone portion is located inside the connecting pipe.

[0011] Furthermore, the length of the gas mixing annulus corresponding to the flow development zone is greater than or equal to three times the distribution height of the oxygen distribution holes in the outer cylinder.

[0012] Furthermore, the outer cylinder corresponding to the diffusion mixing zone includes multiple interconnected outwardly expanding outer conical shells in a trumpet shape; the cone angle of the outer conical shell is less than or equal to 12 degrees; and the outlet end of the outer cylinder corresponding to the diffusion mixing zone is provided with a multi-stage distribution perforated plate.

[0013] Furthermore, the central cylinder corresponding to the diffusion mixing zone includes multiple interconnected, inwardly concave inner conical shells; the cone angle of the inner conical shell is less than or equal to 12 degrees; the distance between the end of the inner conical shell on the central cylinder and the outlet end of the outer cylinder is greater than or equal to 0.8 times the diameter of the outlet end of the outer cylinder.

[0014] An acetylene cracking furnace includes an acetylene cracking reaction device and the aforementioned acetylene cracking furnace mixing distributor; the outer cylinder outlet end of the acetylene cracking furnace mixing distributor is connected to the acetylene cracking reaction device.

[0015] The beneficial effects of this invention are: This invention discloses a mixing distributor for an acetylene cracking furnace, comprising a central cylinder and an outer cylinder. The central cylinder is disposed inside the outer cylinder, and the outer cylinder and the central cylinder cooperate to form a gas mixing annulus, which sequentially forms an initial mixing zone, a flow development zone, and a diffusion mixing zone from top to bottom. A natural gas inlet assembly is provided at the upper end of the outer cylinder, and an oxygen inlet assembly is provided on its outer periphery. Natural gas enters the gas mixing annulus with a narrow radial diffusion path through the natural gas inlet assembly, guided by a flow divider, a baffle, and oxygen distribution holes, and then enters the gas mixing annulus with a narrow radial diffusion path to merge with the natural gas. The mixture is then fully mixed through the initial mixing zone, the flow development zone, and the diffusion mixing zone. This acetylene cracking furnace mixing distributor of the present invention achieves efficient mixing of natural gas and oxygen, and has a simple structure, small overall size, and is easy to manufacture and maintain. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the mixing distributor for the acetylene cracking furnace of the present invention; In the attached diagram: 1-Central cylinder, 2-Outer cylinder, 3-Gas mixing annulus, 4-Initial mixing zone, 5-Flow development zone, 6-Diffusion mixing zone, 7-Natural gas inlet assembly, 8-Oxygen inlet assembly, 9-Distribution cylinder, 10-Oxygen inlet, 11-Oxygen distribution hole, 12-Baffle, 13-Flow divider, 14-Connecting fitting, 15-Cone, 16-Connecting flange, 17-Outer conical shell, 18-Inner conical shell. Detailed Implementation

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] Example 1: See attached Figure 1This invention discloses a mixing distributor for an acetylene cracking furnace, comprising a central cylinder 1, an outer cylinder 2, a natural gas inlet assembly 7, and an oxygen inlet assembly 8. The central cylinder 1 is coaxially disposed inside the outer cylinder 2, and can be fixed inside the outer cylinder 2 by stiffening plates. A narrow radial diffusion path gas mixing annular gap 3 is formed between the central cylinder 1 and the outer cylinder 2, providing a continuous flow channel for gas mixing. The outer cylinder 2 serves as the external support structure of the mixer. Its upper end is connected to the natural gas inlet assembly 7. Natural gas enters the gas mixing annular gap 3 from the natural gas inlet assembly 7 and undergoes preliminary mixing with oxygen. An oxygen inlet assembly 8 is provided on the upper outer periphery of the outer cylinder 2. Oxygen is injected into the gas mixing annular gap 3 from the oxygen inlet assembly 8 in a direction perpendicular to the natural gas and undergoes preliminary mixing with the natural gas. The gas mixing annular gap 3 forms an initial mixing zone 4, a flow development zone 5, and a diffusion mixing zone 6 from top to bottom. Natural gas and oxygen enter the gas mixing annular gap 3 and undergo preliminary mixing in the initial mixing zone 4, and then pass through the flow development zone 5. Since the natural gas and oxygen enter the gas mixing annular gap 3 in a vertical and high-speed direction, turbulent flow is easily generated when mixing in the initial mixing zone 4. The mixed gas further adjusts the flow state in the flow development zone 5 to promote uniform mixing, which can ensure that the circumferential swirling flow of the mixed gas is fully developed. Finally, it slowly transitions through the diffusion mixing zone 6, and the mixed gas is fully and uniformly mixed. At the same time, the uniformity of the outlet concentration distribution and velocity distribution is ensured by limiting the distance between the inner conical shell at the end of the central cylinder and the outlet and setting a multi-stage distribution orifice plate. The present invention provides a mixing distributor for an acetylene cracking furnace, which achieves efficient and uniform mixing of natural gas and oxygen, and has a simple and compact structure, small overall size, and is easy to manufacture and maintain.

[0022] Specifically, the oxygen inlet assembly 8 includes a distribution cylinder 9, a baffle 12, and a flow divider 13. The distribution cylinder 9 is an annular structure, circumferentially fixed to the outer periphery of the upper part of the outer cylinder 2. At least one oxygen inlet 10 is provided on the side wall of the distribution cylinder 9, and the oxygen inlet 10 is used to connect to an external oxygen delivery pipeline. Several oxygen distribution holes 11 are provided on the part of the outer cylinder 2 surrounded by the distribution cylinder 9. The total cross-sectional area of ​​the oxygen distribution holes 11 is smaller than the cross-sectional area of ​​the gas mixing annular gap 3. After oxygen enters the distribution cylinder 9, it enters the gas mixing annular gap 3 through the oxygen distribution holes 11. The small oxygen distribution holes 11 can increase the gas flow rate, increase the dynamic pressure head, and decrease the static pressure head. Natural gas enters the gas mixing annular gap 3 from above in a direction perpendicular to the oxygen. The static pressure of the natural gas flow can induce the radially entering oxygen into the annular gap and flow downstream (equivalent to drawing in oxygen). Since oxygen and natural gas are highly flammable when mixed, if the traditional forced mixing method is used, that is, the oxygen is pushed in from the outside, it will cause local stagnation of the airflow at the oxygen distribution holes 11. That is, under the same cross-sectional area, the low flow rate of oxygen at the oxygen distribution holes 11 is lower than the high flow rate of natural gas in the annular gap, which can easily cause local ignition. In addition, to ensure better mixing of oxygen entering the gas mixing annular gap 3 from the oxygen distribution hole 11 and natural gas, the inner and outer edges of the oxygen distribution hole 11 are rounded for smooth transition, avoiding ignition caused by burrs and affecting the mixing flow. Furthermore, the radius of the rounded corner at the lower inner edge of the oxygen distribution hole is larger than the radius at the upper edge and both sides, so as to guide more downward flow component after the oxygen enters. A baffle 12 is also coaxially provided inside the distribution cylinder 9. The baffle 12 is an annular thin-walled structure with openings on both the upper and lower sides. The baffle 12 is fixed circumferentially around the outer circumference of the outer cylinder 2 and completely surrounds the area of ​​the oxygen distribution hole 11 on the outer cylinder 2. The baffle 12 forms a buffer for the oxygen passing through the oxygen distribution hole 11. After the oxygen enters the distribution cylinder 9, it is guided by the baffle 12 to diffuse in the circumferential and vertical directions, avoiding local accumulation of oxygen in the distribution cylinder 9. The oxygen then flows through the openings on the upper and lower sides of the baffle 12 and through the oxygen distribution hole 11, buffering the airflow and preventing it from flowing directly at high speed into the distribution hole and causing greater flow deviation. Furthermore, multiple diverter plates 13 are provided at the oxygen inlet 10 of the distribution cylinder 9. The diverter plates 13 are evenly distributed longitudinally along the oxygen inlet 10, and the two ends of the diverter plates 13 are fixed to the inner side of the oxygen inlet 10. When oxygen enters the distribution cylinder 9 through the oxygen inlet 10, the oxygen flow will be divided into multiple parallel airflows by the diverter plates 13, realizing the initial distribution of the oxygen flow along the circumference of the distribution cylinder 9, further avoiding local accumulation of oxygen in the distribution cylinder 9. After the oxygen enters the distribution cylinder 9 through the diverter plates 13, it is diverted again in the circumference of the distribution cylinder 9 due to the guidance of the baffle 12, so that there will not be a very large circumferential flow deviation, laying the foundation for subsequent uniform gas distribution.In the oxygen inlet assembly 8 of this invention, external oxygen enters the distribution cylinder 9 via the oxygen inlet 10 through a delivery pipe, is divided into multiple airflows by a flow divider 13, and then enters the distribution cylinder 9. After being buffered by a baffle 12, the oxygen diffuses circumferentially under the baffle's buffering effect. Since the total cross-sectional area of ​​the oxygen distribution holes 11 is smaller than the cross-sectional area of ​​the gas mixing annulus 3, the flow velocity of the oxygen through the oxygen distribution holes 11 will be significantly increased. According to fluid mechanics principles, the increased flow velocity leads to an increase in dynamic head and a decrease in static pressure at the oxygen distribution holes 11, creating an ejection effect that continuously and stably injects oxygen from the distribution cylinder 9 into the gas mixing annulus 3. Simultaneously, the large-radius rounded corner design on the lower inner edge of the oxygen distribution holes 11 guides the oxygen into the gas mixing annulus 3, forming a downward flow component that cross-flows with the natural gas flowing axially along the gas mixing annulus 3, providing favorable airflow direction conditions for initial mixing. Furthermore, the rounded corner transition structure avoids the risk of local eddies and burr ignition caused by sharp edges, ensuring the safety of the mixing process.

[0023] Specifically, the natural gas inlet assembly 7 includes a connecting pipe fitting 14, a connecting flange 16, and a cone 15. The connecting flange 16 is located at the top of the connecting pipe fitting 14 and is used to connect to an external natural gas transmission pipeline. The bottom of the connecting pipe fitting 14 is sealed and connected to the upper inlet of the outer cylinder 2, forming a transition channel for natural gas to enter the gas mixing annular gap 3. The connecting pipe fitting 14 can be either a reducer structure or a straight cylindrical structure, with a preferred design being larger at the top and smaller at the bottom. Its structural dimensions can be determined comprehensively based on the external pipeline dimensions, the mixer outlet dimensions, and the product scale. An integrally formed cone 15 is located at the top of the central cylinder 1. The tip of the cone 15 points upwards and partially extends into the interior of the connecting pipe fitting 14, forming a symmetrical funnel-shaped guide channel with the inner wall of the connecting pipe fitting 14. Natural gas enters the connecting pipe fitting 14 through the connecting flange 16 via the external pipeline. Under the combined action of the reducer structure and the upper cone 15 of the central cylinder 1, the gas flow is guided to the narrower radial diffusion path of the gas mixing annular gap 3 between the central cylinder 1 and the outer cylinder 2. The top-to-bottom tapered structure, in conjunction with the cone 15, serves three key functions: First, it divides the natural gas inlet profile into two symmetrical funnel shapes, ensuring a uniform radial distribution of natural gas before it enters the annulus, preventing excessively high or low local velocities. Second, the tapered design of the connecting pipe 14 reduces the diameter of the central cylinder 1, providing space for the small cone angle design of the inner cone assembly at the bottom of the central cylinder 1, resulting in a smoother cone angle change and favorable conditions for rectifying the mixed gas flow. Third, while ensuring the cross-sectional area of ​​the gas mixing annulus 3 meets the flow requirements, it appropriately increases the radial clearance of the gas mixing annulus 3, reducing mutual disturbance between fluid boundary layers, stabilizing the flow state, and creating a good flow environment for the uniform mixing of natural gas and oxygen. It also facilitates the welding of the stiffeners between the outer cylinder 2 and the central cylinder 1. The guiding effect of the cone 15 at the top of the central cylinder 1 further optimizes the flow direction of the natural gas, allowing it to flow smoothly along the annulus axial direction and form an efficient cross-flow contact with the radially entering oxygen in the initial mixing zone 4.

[0024] Specifically, the flow development zone 5 is a channel located below the initial mixing zone 4 within the gas mixing annulus 3. Since oxygen and natural gas enter the mixer perpendicularly and flow at high speed, the mixed gas is prone to turbulent flow in the initial stage of mixing. Therefore, the flow development zone 5 is necessary to ensure sufficient circumferential swirling development of the mixed gas, providing favorable initial conditions for the subsequent diffusion mixing zone 6. Both the central cylinder 1 and the outer cylinder 2 of the flow development zone 5 are cylindrical structures. The length of the flow development zone 5 is designed to be more than three times the distribution height of the oxygen distribution holes 11, providing ample development space for the mixed gas flow. This allows the mixed gas to form a stable swirling flow in the circumferential direction. This swirling effect significantly enhances the turbulent mixing intensity of the two gases, breaks the gas boundary layer, promotes molecular diffusion, and enables natural gas and oxygen to gradually achieve initial uniform mixing during the flow process.

[0025] Specifically, the diffusion mixing zone 6 includes an inner cone assembly and an outer cone assembly. The inner and outer cones are connected to the cylinder at the same elevation to ensure stable flow. The inner cone assembly is integrally formed with the bottom of the central cylinder 1 and consists of multiple sequentially connected, inwardly constricted inner cone shells 18. The outer cone assembly is integrally formed with the outer cylinder 2 and consists of multiple sequentially connected, outwardly expanding outer cone shells 17. The inner and outer cone assemblies are coaxially arranged, forming a gradually expanding annular diffusion channel, i.e., the diffusion mixing zone 6. The preferred cone angle of all inner cone shells 18 and outer cone shells 17 does not exceed 12°, and the preferred distance between the bottom end of the bottom inner cone shell 18 and the bottom end of the bottom outer cone shell 17 is greater than or equal to 0.8 times the bottom diameter of the bottom outer cone shell 17. After the mixed gas forms a stable swirling flow in the flow development zone 5, it enters the channel between the inner cone shells 18 and outer cone shells 17 in the diffusion mixing zone 6. As the cross-sectional area of ​​the channel gradually increases along the axial direction, according to the continuity equation of fluid mechanics, the velocity of the mixed gas gradually decreases, and the residence time increases accordingly. This provides sufficient time for radial diffusion mixing of the mixed gas, allowing the concentration distribution of natural gas and oxygen to gradually become more uniform along the radial direction. Simultaneously, the inner conical shell 18 and outer conical shell 17 employ a small cone angle design with a preferred cone angle not exceeding 12°, achieving a slow transition in the flow channel. This avoids local eddies and velocity unevenness caused by abrupt changes in the channel cross-sectional area, resulting in a more uniform radial velocity distribution of the mixed gas. This effectively reduces the formation of local low-velocity regions and lowers the risk of early ignition due to excessively long local residence times. The rectifying section between the end of the central cylinder 1 and the outlet end of the outer cylinder 2 further adjusts the flow pattern of the mixed gas, making the radial airflow more stable and ensuring a uniform velocity and concentration field at the outlet cross-section. Furthermore, based on flow field analysis, a multi-stage distribution orifice plate can be installed at the outlet of the diffusion mixing zone 6 to better homogenize the radial velocity distribution and increase the flow velocity, preventing backfire.

[0026] Example 2: An acetylene cracking furnace includes an acetylene cracking reactor and an acetylene cracking furnace mixing distributor as described in Example 1. The outlet end of the outer cylinder 2 of the acetylene cracking furnace mixing distributor is connected to the acetylene cracking reactor. After connection, the connection between the cracking furnace and the mixing distributor is externally insulated or lined to reduce heat loss. The preferred structure is an inner lining, which protects the connecting fasteners. Natural gas and oxygen are uniformly mixed in the acetylene cracking furnace mixing distributor before entering the acetylene cracking reactor for reaction. Other components of the acetylene cracking furnace are well known to those skilled in the art, therefore, they will not be described in detail here.

[0027] All technical features in this embodiment can be freely combined according to actual needs. The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention 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 solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

[0028] The above embodiments are preferred implementations of the present invention. In addition, other implementations are also included. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A mixing distributor for an acetylene cracking furnace, characterized in that: It includes a central cylinder (1) and an outer cylinder (2); the central cylinder (1) is set inside the outer cylinder (2), and the outer cylinder (2) and the central cylinder (1) cooperate to form a gas mixing annular gap (3), which forms an initial mixing zone (4), a flow development zone (5) and a diffusion mixing zone (6) from top to bottom; the upper end of the outer cylinder (2) is provided with a natural gas inlet assembly (7), and the outer periphery is provided with an oxygen inlet assembly (8); natural gas and oxygen enter the gas mixing annular gap (3) from the natural gas inlet assembly (7) and the oxygen inlet assembly (8) respectively, and are fully mixed through the initial mixing zone (4), the flow development zone (5) and the diffusion mixing zone (6).

2. The acetylene cracking furnace mixing distributor according to claim 1, characterized in that: The oxygen inlet assembly (8) includes a distribution cylinder (9); the upper part of the outer cylinder (2) is provided with the distribution cylinder (9) around the outer cylinder (2); the distribution cylinder (9) is provided with an oxygen inlet (10); the part of the outer cylinder (2) surrounded by the distribution cylinder (9) is provided with an oxygen distribution hole (11); the total cross-sectional area of ​​the oxygen distribution hole (11) is smaller than the cross-sectional area of ​​the gas mixing annular gap (3).

3. The acetylene cracking furnace mixing distributor according to claim 2, characterized in that: The oxygen inlet assembly (8) also includes a baffle (12); the baffle (12) is arranged around the oxygen distribution hole (11) along the circumference of the outer cylinder (2) and is located inside the distribution cylinder (9); the upper and lower sides of the baffle (12) are provided with openings for oxygen to enter.

4. The acetylene cracking furnace mixing distributor according to claim 2, characterized in that: The distribution cylinder (9) has multiple flow dividers (13) at the oxygen inlet (10); the flow dividers (13) are arranged longitudinally along the oxygen inlet (10).

5. The acetylene cracking furnace mixing distributor according to claim 2, characterized in that: The oxygen distribution hole (11) has rounded corners on both sides for a smooth transition.

6. A mixing distributor for an acetylene cracking furnace according to any one of claims 1 to 5, characterized in that: The natural gas inlet assembly (7) includes a cone (15) and a connecting pipe (14) for guiding flow; the connecting pipe (14) has a connecting flange (16) at the top and is connected to the upper inlet of the outer cylinder (2) at the bottom; the connecting pipe (14) is a reducer structure or a straight cylindrical structure; the top of the central cylinder (1) is provided with a cone (15); part of the cone (15) is located inside the connecting pipe (14).

7. The acetylene cracking furnace mixing distributor according to claim 2, characterized in that: The length of the gas mixing annulus (3) corresponding to the flow development zone (5) is greater than or equal to three times the distribution height of the oxygen distribution hole (11) in the outer cylinder (2).

8. The acetylene cracking furnace mixing distributor according to claim 1, characterized in that: The outer cylinder (2) corresponding to the diffusion mixing zone (6) includes multiple connected outwardly expanding outer conical shells (17) in the shape of a trumpet; the cone angle of the outer conical shell (17) is less than or equal to 12 degrees; the outlet end of the outer cylinder (2) corresponding to the diffusion mixing zone (6) is provided with a multi-stage distribution perforated plate.

9. A mixing distributor for an acetylene cracking furnace according to claim 8, characterized in that: The central cylinder (1) corresponding to the diffusion mixing zone (6) includes multiple connected, inwardly concave inner conical shells (18); the cone angle of the inner conical shell (18) is less than or equal to 12 degrees; the distance between the end of the inner conical shell (18) on the central cylinder (1) and the outlet end of the outer cylinder (2) is greater than or equal to 0.8 times the diameter of the outlet end of the outer cylinder (2).

10. An acetylene cracking furnace, characterized in that: It includes a reaction device and an acetylene cracking furnace mixing distributor as described in any one of claims 1 to 9; the outlet end of the outer cylinder (2) of the acetylene cracking furnace mixing distributor is connected to the reaction device.

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