Gas premixing and uniform distribution structure

Abstract

The invention provides a gas premixing and uniform distribution structure which comprises a jet flow premixer, a surge bin, a jet ring pipe, a multi-stage cyclone mixer, a gas flow distribution plate, a flow guide disc and a segmentation rectifier, one end of the jet premixer is inserted into the surge bin, a flange of the jet ring pipe is connected to the other end of the jet premixer, a multi-stage cyclone mixer is fixed in the jet premixer, an airflow distribution plate is fixed at the top of the surge bin, and a flow guide disc is fixed at one end, inserted into the jet premixer, of the jet ring pipe. A plurality of jet orifices are vertically and uniformly formed in the conical surface of the jet premixer, the multi-stage cyclone mixer comprises a first-stage cyclone blade and a second-stage cyclone blade, the rotating directions of the first-stage cyclone blade and the second-stage cyclone blade are opposite, and a segmentation rectifier is fixed around an opening at one end, inserted into the surge bin, of the jet premixer. The problems of combustion oscillation, local high temperature, pollutant emission increase, medium damage and the like caused by non-uniform mixing and non-uniform distribution are solved, so that the superiority of super-enthalpy combustion is fully exerted.

Description

Technical Field

[0001] This invention relates to the field of combustion technology, and more specifically to a gas premixed uniform distribution structure for achieving superenthalpic combustion in porous media. Background Technology

[0002] Fuels can be classified into three categories based on their calorific value: low-calorific-value fuels, medium-calorific-value fuels, and high-calorific-value fuels.

[0003] Currently, low-calorific-value by-product gases from industrial production, such as those from the early stages of converter steelmaking, are often released by most companies during the initial and final stages of converter steelmaking due to their poor combustibility. This not only wastes energy but also pollutes the environment. However, with societal development and the decreasing availability of fossil fuels like coal and oil, and a growing awareness of expanding energy utilization and energy conservation and emission reduction, the recovery and effective utilization of low-calorific-value fuel gases in industrial production are becoming increasingly crucial.

[0004] Porous media combustion is an advanced combustion technology for treating ultra-low calorific value gases. Its core lies in passing a fuel-air mixture through a porous medium (such as foamed ceramics or foamed metals) with high specific surface area and good thermal conductivity, where combustion occurs within the pores. Compared to traditional free-flame combustion, porous media combustion offers significant advantages such as stable combustion, a wide load adjustment range, and low pollutant emissions. Among these advantages, superenthalpy combustion is one of the most distinctive phenomena of porous media combustion. It efficiently preheats the unburned premixed gas through radiation and convection heat transfer in the porous solid matrix, allowing the combustion reaction to occur at temperatures far exceeding the theoretical adiabatic flame temperature. This significantly improves combustion efficiency and effectively suppresses the formation of pollutants such as NOx.

[0005] However, the superiority of porous media superenthalpy combustion technology depends heavily on a key premise: the fuel and air must be fully and uniformly premixed before entering the porous media combustion zone, and the flow field must be uniformly distributed across the entire cross-section of the burner.

[0006] Currently, common premixed and gas distribution structures are usually quite simple, for example: Simple mixer: Fuel is injected into the airflow channel through a central orifice and mixed by a downstream straight section. This method has limited mixing effect, requires a relatively long mixing distance, and is difficult to achieve adequate premixing in compact burners.

[0007] Perforated plate flow equalizer: A single or multi-perforated plate is placed upstream of the premixed gas to equalize the airflow using its flow resistance. While this method can improve distribution uniformity, it does not contribute to improving premixing quality and increases system pressure drop. Furthermore, perforated plates are prone to overheating and damage due to tempering or thermal radiation.

[0008] Swirlers: They enhance mixing by generating swirling currents, but the swirling currents disrupt the axial symmetry of the flow field, causing flame shape shifts and making it difficult to form stable and uniform planar combustion waves in porous media.

[0009] In summary, the existing technology has the following technical shortcomings: the lack of an integrated solution that can simultaneously achieve efficient premixing, uniform cross-sectional distribution, low flow resistance, and a compact and reliable structure has become one of the bottlenecks restricting the large-scale industrial application of porous media superenthalpy combustion technology. Summary of the Invention

[0010] The purpose of this invention is to provide a gas premixed uniform distribution structure.

[0011] This invention is implemented by the following technical solution: A gas premixing and uniform distribution structure includes a jet premixer, a buffer chamber, a jet ring pipe, a multi-stage swirling mixer, an airflow distribution plate, and a guide plate. One end of the jet premixer is inserted into the buffer chamber, and the jet ring pipe is flanged and connected to the other end of the jet premixer. The jet premixer is a cylindrical cavity. An insertion hole is opened at one end of the jet premixer along the axial direction, and the jet ring pipe passes through the insertion hole. An air inlet pipe is provided tangentially on the side wall of the jet premixer, and the air inlet pipe is located below the jet ring pipe. The multi-stage swirling mixer is fixed inside the jet premixer. An airflow distribution plate is fixed on the top of the buffer chamber. The top of the airflow distribution plate has several through holes. A guide plate is fixed at one end of the jet ring pipe inserted into the jet premixer. The guide plate is generally frustum-shaped, and multiple injection ports are vertically and uniformly opened on its conical surface.

[0012] Preferably, the multi-stage swirl mixer includes a first-stage swirl blade and a second-stage swirl blade, wherein the first-stage and second-stage swirl blades rotate in opposite directions, and the second-stage swirl blade rotates counterclockwise.

[0013] Preferably, the blade angles of the primary and secondary swirl blades are 55°-60°, and the two adjacent end faces of the primary and secondary swirl blades are either overlapped or perpendicularly connected.

[0014] Preferably, the diameter of the through holes on the airflow distribution plate gradually increases from 25mm to 30mm from the center to the edge.

[0015] Preferably, the guide plate has twelve spray nozzles evenly distributed on it, and the spray nozzles are shaped like waist grooves.

[0016] Preferably, a segmentation rectifier is fixed to the opening of the airflow distribution plate on one side wall of the jet premixer inserted into the buffer chamber.

[0017] Preferably, the segmented rectifier includes multiple segmented rectifier plates and a cover plate, with the cover plate fixed to the top of the multiple segmented rectifier plates.

[0018] Advantages of this invention: I. By combining macroscopic mixing with microscopic mixing through a tiered mixing mode of "swirl premixing and multi-stage reverse swirl enhanced mixing", a high degree of uniformity of fuel and air is achieved within an extremely short flow distance, with a mixing uniformity of over 95%. Second, through the three-stage uniform distribution mechanism of "swirl mixing + segmentation rectification + porous plate uniform flow", the non-uniformity caused by swirl and turbulence is completely eliminated, providing a more ideal inflow condition for porous media, with a velocity distribution uniformity coefficient higher than 0.97. This invention is suitable for burners of various power ratings. The end-segment rectifier and airflow distribution plate are made of high-temperature resistant alloys or ceramic materials, possessing excellent mechanical strength and thermal stability, effectively preventing flashback and thermal deformation, with an overall pressure drop of less than 10 kPa. It fundamentally solves problems such as combustion oscillation, localized high temperature, increased pollutant emissions, and media damage caused by uneven mixing and distribution, allowing the superiority of super-enthalpy combustion to be fully realized. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a structural perspective view of the present invention; Figure 3 This is a schematic diagram of the jet premixer. Figure 4 yes Figure 3 Enlarged view of point A in the middle; Figure 5 This is a partial structural diagram; Figure 6 This is a schematic diagram of a multi-stage cyclone mixer with two overlapping and connected end faces. Figure 7 This is a schematic diagram of a multi-stage cyclone mixer with its two end faces vertically connected.

[0020] In the diagram: 1. Jet premixer, 1.1. Inlet, 1.2. Inlet pipe, 2. Buffer chamber, 3. Injection ring pipe, 4. Multi-stage swirl mixer, 4.1. First-stage swirl blade, 4.2. Second-stage swirl blade, 5. Airflow distribution plate, 5.1. Through hole, 6. Guide plate, 6.1. Injection port, 7. Divider rectifier, 7.1. Divider rectifier plate, 7.2. Cover plate. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figures 1 to 7 As shown, a gas premixed uniform distribution structure includes a jet premixer 1, a buffer chamber 2, an injection ring pipe 3, a multi-stage swirl mixer 4, an airflow distribution plate 5, a guide plate 6, and a segmentation rectifier 7. The jet premixer 1 has an insertion hole 1.1 at one end along the axial direction. Flanges are fixed to the edge of one end of the jet premixer 1 and the middle surface of the injection ring pipe 3. The injection ring pipe 3 is connected by the flanges, and one end of the injection ring pipe 3 passes through the insertion hole 1.1 of the jet premixer 1. The side wall of the jet premixer 1 is provided with an air inlet pipe 1.2 tangentially. It should be noted that air and fuel gas can be interchanged between the injection ring pipe 3 and the air inlet pipe 1.2 and finally introduced into the jet premixer 1 to achieve mixing.

[0023] In this design, only fuel gas enters from the injection ring pipe 3, and air enters from the intake pipe 1.2; the intake pipe 1.2 is located below the injection ring pipe 3, and this tangential design causes a strong air vortex to form immediately after the air enters.

[0024] The jet premixer 1 is a cylindrical cavity with a length of 5500 mm and an inner diameter of 500 mm. The purpose of this long design is to reduce the airflow velocity and provide sufficient space and time for the initial mixing of fuel and air.

[0025] One end of the injection ring pipe 3, inserted into the jet premixer 1, is fixed with a guide plate 6. The guide plate 6 is shaped like a frustum, with twelve injection ports 6.1 vertically and evenly distributed on its conical surface. The injection ports 6.1 are shaped like waist grooves. Fuel gas is injected into the injection ring pipe 3 in the form of a high-speed, fine jet and ejected from the twelve injection ports 6.1, contacting the swirling air. The shearing action of the swirling air is used to achieve the initial breaking and macroscopic mixing of the fuel jet.

[0026] The jet premixer 1 contains a multi-stage swirling mixer 4, which includes a first-stage swirling blade 4.1 and a second-stage swirling blade 4.2. The first-stage and second-stage swirling blades 4.1 and 4.2 rotate in opposite directions, with the second-stage swirling blade 4.2 rotating counterclockwise. The blade angle of the first-stage and second-stage swirling blades 4.1 and 4.2 is 57°. The adjacent end faces of the first-stage and second-stage swirling blades 4.1 and 4.2 are either overlapped or perpendicularly connected. When the initially mixed gas passes through the first-stage swirling blade 4.1 and generates a strong swirling flow, it is immediately and forcibly twisted by the opposing second-stage swirling blade 4.2. This process generates a violent velocity gradient, shearing, and collision within a very short axial distance, pushing the large-scale gas cloud mixing towards the microscopic molecular-scale mixing. As a result, when the gas exits the mixer, the fuel and air have reached a highly homogeneous premixed state.

[0027] One end of the jet premixer 1 is closed and inserted into the buffer chamber 2. The upper surface of the end of the jet premixer 1 inserted into the buffer chamber 2 has an opening, and a dividing rectifier 7 is fixed around the opening. The dividing rectifier 7 is directly opposite the opening of the airflow distribution plate 5. The dividing rectifier 7 includes sixteen dividing rectifier plates 7.1 and a cover plate 7.2. The sixteen dividing rectifier plates 7.1 are arranged and fixed at intervals along the edge of the opening on the side wall of the jet premixer 1. The cover plate 7.2 is fixed on the top of the sixteen dividing rectifier plates 7.1. The dividing rectifier plates 7.1 are 8mm thick and made of high-temperature 310S stainless steel.

[0028] These segmented rectifier plates 7.1 effectively disperse the swirling flow delivered from the jet premixer 1. Their function is to convert the fluid's kinetic energy into thermal energy, dissipate disordered pulsations, and thus "combine" the airflow into a near-laminar state with consistent direction and stable velocity, laying the foundation for the final uniform distribution.

[0029] A gas flow distribution plate 5 is fixed to the top of the buffer chamber 2. The gas flow distribution plate 5 is made of heat-resistant alloy steel plate with a thickness of 18mm. To achieve the ultimate uniform flow rate, the top of the gas flow distribution plate 5 is provided with several through holes 5.1, which gradually increase from the center to the edge. The diameter of the through holes 5.1 on the gas flow distribution plate 5 gradually increases from 25mm to 30mm from the center to the edge, so that the flow resistance gradually decreases from the center to the edge. This design compensates for the tendency of the airflow to naturally concentrate towards the center caused by the burner wall effect. By "guiding" the flow to the edge, the airflow is forced to be distributed at a uniform speed (uniformity > 98%) into the downstream porous medium combustion zone.

[0030] Working Principle: Combustion-supporting air is injected at high speed into the jet premixer 1 through the tangential intake pipe 1.2, forming a strong air vortex. Simultaneously, fuel gas is ejected from the injection port 6.1 of the guide plate 6, undergoing preliminary momentum exchange and mixing under the shearing action of the swirling air. Subsequently, the premixed gas enters the multi-stage swirling mixer 4, where it undergoes intense shearing and collision due to the counter-current swirling action of the first-stage swirling blades 4.1 and the second-stage swirling blades 4.2, achieving uniform micro-scale mixing of fuel and air within a very short distance. The uniformly mixed swirling gas is then effectively dispersed by the segmented rectifier plate 7, which axializes the airflow, eliminates velocity pulsations, and forms a uniform and stable straight flow. Finally, the airflow enters the porous medium combustion chamber at an absolutely uniform velocity through the airflow distribution plate 5 with a variable porosity structure, providing perfect preconditions for stable and efficient super-enthalpy combustion.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gas premix uniform distribution structure, characterized by, The utility model relates to a kind of jet premixers, buffer bin, injection ring pipe, multi-stage cyclone mixer, airflow distribution plate and flow guide disc;The jet premixer (1) is inserted in buffer bin (2) in one end, the flange connection of injection ring pipe (3) is in the other end of jet premixer (1), the jet premixer (1) is cylindrical cavity, the insertion hole (1.1) is set in the axial one end of the jet premixer (1), the injection ring pipe (3) is inserted in insertion hole (1.1), the sidewall of the jet premixer (1) is provided with air inlet pipe (1.2) along tangential direction, air inlet pipe (1.2) is below injection ring pipe (3);Multi-stage cyclone mixer (4) is fixed in the jet premixer (1), airflow distribution plate (5) is fixed at the top of buffer bin (2), a plurality of through holes (5.1) are set in the top of airflow distribution plate (5), flow guide disc (6) is fixed in the one end of jet premixer (1) inserted in injection ring pipe (3), the overall flow guide disc (6) is circular truncated cone, and a plurality of injection ports (6.1) are vertically and uniformly set on the conical surface thereof.

2. The gas premix uniform distribution structure according to claim 1, characterized in that, The multi-stage cyclone mixer (4) includes primary cyclone vane (4.1) and secondary cyclone vane (4.2), the primary cyclone vane (4.1) and the secondary cyclone vane (4.2) are opposite in rotation direction, and the secondary cyclone vane (4.2) is counterclockwise.

3. The gas premix uniform distribution structure according to claim 2, wherein, The blade angle of the primary cyclone vane (4.1) and the secondary cyclone vane (4.2) is 55°-60°, and the two end faces of the primary cyclone vane (4.1) and the secondary cyclone vane (4.2) are coincidently connected or perpendicularly connected.

4. The gas premix uniform distribution structure according to claim 1, wherein, The aperture of the through hole (5.1) on the airflow distribution plate (5) gradually changes from 25 mm to 30 mm from the center to the edge.

5. The gas premix uniform distribution structure according to claim 1, wherein, The flow guide disc (6) is uniformly provided with twelve injection ports (6.1), and the injection port (6.1) is in the form of a waist groove.

6. The gas premix uniform distribution structure according to claim 1, wherein The sidewall of the jet premixer (1) inserted in the buffer bin (2) is fixed with a segmented rectifier (7) opposite the opening of the airflow distribution plate (5).

7. The gas premix uniform distribution structure according to claim 6, wherein The segmented rectifier (7) includes a plurality of segmented rectifier plates (7.1) and a cover plate (7.2), the segmented rectifier plates (7.1) are fixed and arranged along the opening edge of the sidewall of the jet premixer (1) at intervals, and the cover plate (7.2) is fixed at the top end of the segmented rectifier plates (7.1).

Images