Natural gas and biomass co-combustion device

Abstract

The invention provides a natural gas and biomass co-combustion combustion device which comprises a central air duct, an ignition assembly and an air duct assembly, the central air duct is provided with an air inlet and an air outlet, and the ignition assembly comprises an ignition part and a central air gun. The center air gun is connected with the center air duct and can move relative to the center air duct in the axial direction of the center air duct, the center air gun is arranged in the center air duct and used for introducing natural gas, the ignition part is arranged in the second end of the center air gun and is adjacent to the air outlet, and the natural gas exhausted from the second end of the center air gun is used for being mixed with combustion-supporting gas to form mixed gas. The ignition part is used for igniting mixed gas, the air duct assembly comprises a primary air duct, a gas collecting ring and a secondary air duct, the central air duct is sleeved with the primary air duct, the primary air duct is sleeved with the gas collecting ring, and the gas collecting ring is sleeved with the secondary air duct. According to the natural gas and biomass co-combustion combustion device, biomass ignition stable combustion is achieved through natural gas, the overall structure is easy to reform, and reliability is high.

Description

Technical Field

[0001] This invention belongs to the field of boiler technology, specifically relating to a natural gas-biomass co-combustion device. Background Technology

[0002] With the continuous strengthening of environmental protection and the optimization and adjustment of the energy structure, traditional coal-fired boilers are gradually being replaced by clean energy boilers. In the field of low-carbon transformation technology for converting coal-fired boilers to gas-fired boilers, "coal-to-gas" has become an important environmental protection measure, playing a significant role in reducing air pollution caused by scattered coal burning and improving air quality.

[0003] Among related technologies, research and practice on co-firing biomass to reduce carbon emissions in coal-to-gas boilers are relatively limited. Although existing gas-fired boilers coupled with biomass often adopt the method of co-firing biomass gasification gas, this method requires the construction of additional biomass gasification furnaces, increasing investment costs and limiting its large-scale promotion and application. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a natural gas-biomass co-combustion combustion device, which uses natural gas to achieve stable ignition and combustion of biomass, and has a simple overall structure and high reliability.

[0006] The natural gas-biomass co-combustion device according to an embodiment of the present invention includes: A central air duct, which has an air inlet and an air outlet, wherein the air inlet is used to introduce combustion-supporting gas; An ignition assembly includes an ignition element and a central air gun. The central air gun is connected to the central air duct and is movable relative to the central air duct along its axial direction. A first end of the central air gun is used to introduce natural gas, and a second end of the central air gun is located inside the central air duct. The ignition element is located inside the second end of the central air gun and arranged adjacent to the air outlet. The natural gas discharged from the second end of the central air gun is used to mix with the combustion-supporting gas to form a mixture, and the ignition element is used to ignite the mixture. A ventilation duct assembly, comprising a primary ventilation duct, a gas collecting ring, and a secondary ventilation duct, wherein the primary ventilation duct is fitted onto the central ventilation duct, the gas collecting ring is fitted onto the primary ventilation duct, and the secondary ventilation duct is fitted onto the gas collecting ring. The primary ventilation duct is used to introduce an airflow carrying biomass pellets, the gas collecting ring is used to introduce natural gas, and the secondary ventilation duct is used to introduce natural wind.

[0007] The natural gas-biomass co-combustion device of this invention mixes natural gas discharged from the central gas gun with combustion-supporting gas to form a mixture, which is then ignited by an igniter to ensure stable and efficient combustion. A primary air duct carries the airflow of biomass pellets, which mixes with the natural gas for combustion, achieving coupled combustion of biomass and natural gas. This effectively couples the combustion of biomass and natural gas, reducing additional investment costs, improving combustion efficiency, and lowering carbon emissions. It offers significant technical benefits and advantages for environmental protection and the optimization of the energy structure.

[0008] Furthermore, the natural gas-biomass co-combustion device of this invention has wide adaptability, and the biomass particle size and primary air-coal concentration can be adjusted according to actual conditions. It also uses natural gas to achieve stable ignition and combustion of biomass, and the system is simple and highly reliable.

[0009] In some embodiments, the primary air duct includes an air intake section, an enrichment section, and a combustion section connected in sequence. The air intake section has a primary air inlet, and the combustion section has a combustion outlet. In the direction of airflow in the primary air duct, the cross-sectional area of ​​the enrichment section gradually decreases.

[0010] In some embodiments, the natural gas-biomass co-combustion device of the present invention further includes a primary air intake duct, the primary air intake duct being connected to the intake section, the primary air inlet being disposed in the primary air intake duct, and the inner wall surface of the primary air intake duct away from the primary air duct being tangent to the inner peripheral wall of the primary air duct.

[0011] In some embodiments, the air inlet is located at the first end of the central air duct, the air outlet is located at the second end of the central air duct, and the second end of the central air duct is located within the combustion section.

[0012] In some embodiments, at least a portion of the combustion section and the outlet end of the gas collecting ring are both located within the secondary air duct, and the outlet end of the combustion section is located upstream of the outlet end of the gas collecting ring.

[0013] In some embodiments, the gas collecting ring includes a gas collecting body and a gas collecting pipeline. The gas collecting body has a gas collecting inlet, and the gas collecting pipeline is connected to the gas collecting body. There are multiple gas collecting pipelines, which are arranged circumferentially at intervals along the axial direction of the primary air duct. The outlet end of the gas collecting pipeline is located downstream of the outlet end of the combustion section.

[0014] In some embodiments, the ignition assembly further includes a swirler fitted onto the central air gun, and the swirler is located upstream of the ignition element in the direction of airflow within the central air duct.

[0015] In some embodiments, the axis of the central air gun coincides with the axis of the second end of the central air duct.

[0016] In some embodiments, the central air gun further has an exhaust port, which is disposed on the side wall of the central air gun and located downstream of the ignition element. There are multiple exhaust ports, which are arranged circumferentially at intervals along the axis of the central air gun.

[0017] In some embodiments, the natural gas-biomass co-combustion device of the present invention further includes a detection component, which includes a first detection unit and a second detection unit. The first detection unit is connected to the central air duct for monitoring the flame combustion within the central air duct. The inlet of the primary air duct is electrically connected to the first detection unit, and the primary air duct is used to control the opening or closing of the inlet of the primary air duct based on the detection information from the first detection unit. The second detection unit is connected to the primary air duct to monitor the flame combustion inside the primary air duct. The inlet of the secondary air duct and the inlet of the gas collecting ring are both electrically connected to the first detection unit. The inlet of the secondary air duct and the inlet of the gas collecting ring are used to control the opening or closing of the inlet of the secondary air duct and the opening or closing of the inlet of the gas collecting ring in sequence according to the detection information of the second detection unit. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural schematic diagram of the natural gas-biomass co-combustion device according to an embodiment of the present invention.

[0019] Figure 2 This is a cross-sectional schematic diagram of a natural gas-biomass co-combustion device according to an embodiment of the present invention.

[0020] Figure 3 yes Figure 2 An enlarged view of point A shown in the diagram.

[0021] Figure 4 This is a side view of the natural gas-biomass co-combustion device according to an embodiment of the present invention.

[0022] Figure label: 1. Central air duct; 11. Air inlet; 12. Air outlet. 21. Ignition element; 22. Center air gun; 221. Exhaust port; 23. Swirl generator. 31. Primary air duct; 311. Inlet section; 312. Enrichment section; 313. Combustion section; 32. Gas collecting ring; 321. Gas collecting body; 322. Gas collecting pipeline; 33. Secondary air duct. 4. Primary air intake duct; 41. Primary air inlet. 51. First Inspection Department; 52. Second Inspection Department; 6. Stable flame retardant. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] like Figures 1-4 As shown, the natural gas-biomass co-combustion device of this invention includes: a central air duct 1, an ignition assembly, and an air duct assembly.

[0025] The central air duct 1 has an air inlet 11 and an air outlet 12. The air inlet 11 is used to introduce combustion-supporting gas. The ignition assembly includes an igniter 21 and a central air gun 22. The central air gun 22 is connected to the central air duct 1 and is movable relative to the central air duct 1 along the axial direction of the central air duct 1. The first end of the central air gun 22 is used to introduce natural gas, and the second end of the central air gun 22 is located inside the central air duct 1. The igniter 21 is located inside the second end of the central air gun 22 and is arranged adjacent to the air outlet 12. The natural gas discharged from the second end of the central air gun 22 is used to mix with the combustion-supporting gas to form a mixture, and the igniter 21 is used to ignite the mixture.

[0026] Specifically, such as Figures 1-4 As shown, the air inlet 11 of the central air duct 1 is used to introduce combustion-supporting gas (such as air or other oxygen-containing gas), while the air outlet 12 is connected to the combustion chamber (not shown in the figure). A central air gun 22 is provided inside the central air duct 1, and the central air gun 22 is movable along the axial direction of the central air duct 1. Preferably, the outer peripheral wall of the central air gun 22 is connected to the cylinder wall of the central air duct 1 by a sealing structure (such as a rubber gasket) to prevent airflow leakage within the central air duct 1.

[0027] The first end of the central air gun 22 is connected to the natural gas supply pipeline for introducing natural gas. The second end of the central air gun 22 is located inside the central air duct 1, and the ignition element 21 is located inside the second end of the central air gun 22, near the air outlet 12.

[0028] The ventilation duct assembly includes a primary ventilation duct 31, an air collecting ring 32, and a secondary ventilation duct 33. The primary ventilation duct 31 is fitted onto the central ventilation duct 1, the air collecting ring 32 is fitted onto the primary ventilation duct 31, and the secondary ventilation duct 33 is fitted onto the air collecting ring 32. The primary ventilation duct 31 is used to introduce airflow carrying biomass pellets, the air collecting ring 32 is used to introduce natural gas, and the secondary ventilation duct 33 is used to introduce natural wind.

[0029] A primary ventilation duct 31 is fitted outside the central ventilation duct 1 and is used to introduce airflow carrying biomass pellets. A gas collecting ring 32 is fitted outside the primary ventilation duct 31 and is used to introduce natural gas. A secondary ventilation duct 33 is fitted outside the gas collecting ring 32 and is used to introduce natural air.

[0030] Understandably, the central air gun 22 can move along its axis relative to the central air duct 1 to adapt to different operating conditions. The second end of the central air gun 22 is located inside the central air duct 1, that is, the second end of the central air gun 22 does not exceed the air outlet 12 of the central air duct 1, so as to facilitate the mixing of natural gas and combustion-supporting gas and subsequent ignition operations.

[0031] It should be noted that natural gas can be ejected from the second end of the central gas gun 22, and the ejection position is located downstream of the ignition element 21. The ignition element 21 is arranged on the side of the central gas gun 22 and can move axially with the central gas gun 22 to ensure that the mixer can be ignited to form a central flame under any operating condition. Optionally, the ignition element 21 is a high-energy igniter, such as an electronic igniter or a flame igniter.

[0032] In other words, in the natural gas-biomass co-combustion combustion device of this invention, the natural gas discharged from the central gas gun 22 is mixed with the combustion-supporting gas to form a mixed gas, and the ignition element 21 is used to ignite the mixed gas, ensuring the stability and efficiency of the combustion process. The primary air duct 31 carries the airflow of biomass particles, which mixes and burns with natural gas, realizing the coupled combustion of biomass and natural gas. Thus, the effective coupled combustion of biomass and natural gas is achieved, which not only reduces additional investment costs, but also improves combustion efficiency and reduces carbon emissions, demonstrating significant technical effects and advantages for environmental protection and the optimization of the energy structure.

[0033] Furthermore, the natural gas-biomass co-combustion device of this invention has wide adaptability, and the biomass particle size and primary air-coal concentration can be adjusted according to actual conditions. It also uses natural gas to achieve stable ignition and combustion of biomass, and the system is simple and highly reliable.

[0034] In some embodiments, the primary air duct 31 includes an air intake section 311, an enrichment section 312, and a combustion section 313 connected in sequence. The air intake section 311 has a primary air inlet 41, and the combustion section 313 has a combustion outlet. In the direction of airflow in the primary air duct 31, the cross-sectional area of ​​the enrichment section 312 gradually decreases.

[0035] Specifically, such as Figures 1-4 As shown, the primary air inlet 41 is located in the intake section 311 to receive the airflow carrying biomass pellets. In the intake section 311, the airflow velocity and the distribution of biomass pellets can be designed to be relatively uniform to ensure that the biomass pellets can be fully mixed with the airflow.

[0036] The enrichment section 312 follows immediately after the air intake section 311, and its function is to increase the concentration of biomass pellets in the airflow. In the enrichment section 312, the cross-sectional area gradually decreases in the direction of airflow. This design increases the airflow velocity, and due to inertia, the biomass pellets are relatively concentrated in the central area, thereby increasing the pellet concentration.

[0037] The combustion section 313 is the final part of the primary air duct 31. It has a combustion outlet for introducing the biomass pellets and airflow mixture into the combustion chamber. In the combustion section 313, the biomass pellets begin to burn under the influence of combustion-supporting gas, releasing energy.

[0038] Understandably, after biomass pellets are introduced into the primary air duct 31 and enter the primary air-powder duct, they rotate. Under the action of centrifugal force, the biomass pellets move along the inner wall and converge towards the center under the action of the enrichment section 312, generating a dense phase airflow. The remaining part forms a depleted phase airflow. The formed dense phase airflow is heated by the central flame, releasing a large amount of volatiles, which quickly ignite and burn, forming a primary air-powder flame. This flame mixes with the depleted phase airflow and continues forward through the combustion stabilizing tooth 6, generating a backflow. It entrains external gas to heat itself, facilitating the ignition of the airflow entering the subsequent secondary air duct 33 and the gas collecting ring 32.

[0039] Optionally, the inclination angle of the sidewall of the enrichment section 312 is greater than or equal to 15° and less than or equal to 75°. Preferably, the inclination angle of the sidewall of the enrichment section 312 is 30°. The inclination angle design of the sidewall of the enrichment section 312 helps to make the distribution of biomass particles in the airflow more uniform and improve the mixing effect. By optimizing the distribution of biomass particles, the contact area between biomass particles and airflow can be increased, thereby improving combustion efficiency.

[0040] Preferably, the distance between the second end of the central air duct 1 and the enrichment section 312 is greater than or equal to 150 mm and less than or equal to 250 mm. If the distance is too short or too long, ignition will fail due to insufficient biomass particle concentration within the primary air duct 31. Preferably, the outer wall of the central air duct 1 needs to undergo wear-resistant treatment to withstand the scouring effect of the biomass particle airflow. This wear-resistant treatment includes: using wear-resistant coating materials, such as ceramic coatings, cermet coatings, high-chromium alloy coatings, etc.; or, improving the hardness of the outer wall of the central air duct 1 through surface hardening treatment techniques, such as nitriding, carburizing, etc.

[0041] In some embodiments, the natural gas biomass co-combustion device of the present invention further includes a primary air intake duct 4, which is connected to the intake section 311. A primary air inlet 41 is provided in the primary air intake duct 4, and the inner wall surface of the primary air intake duct 4 away from the primary air duct 31 is tangent to the inner peripheral wall of the primary air duct 31.

[0042] Specifically, such as Figures 1-4As shown, the primary air intake duct 4 is connected to the intake section 311, serving as a channel for biomass pellets and airflow to enter the intake section 311. The primary air intake duct 4 is located away from the inner wall of the primary air duct 31, and its outer edge is tangent to the inner peripheral wall of the primary air duct 31. This helps the airflow to form a swirling flow when entering the primary air duct 31, increasing the mixing efficiency of the airflow and biomass pellets.

[0043] Understandably, since the air intake is tangent to the inner wall, the airflow will generate a swirling effect when it enters the primary air duct 31. This helps to mix the biomass pellets with the airflow, facilitates the separation of the dense phase airflow and the light phase airflow, and improves the combustion efficiency of the biomass pellets.

[0044] Furthermore, the design of the primary air intake duct 4 reduces the resistance when airflow enters the primary air duct 31, thereby reducing system energy consumption and improving overall efficiency. Better mixing and combustion efficiency help reduce the emission of unburned biomass particles and harmful gases, improving the environmental performance of combustion.

[0045] In some embodiments, the air inlet 11 is located at the first end of the central air duct 1, and the air outlet 12 is located at the second end of the central air duct 1, with the second end of the central air duct 1 located within the combustion section 313.

[0046] Specifically, such as Figures 1-4 As shown, the air inlet 11 is located at the first end of the central air duct 1 and is used to receive combustion-supporting gases, such as air or oxygen. The air outlet 12 is located at the second end of the central air duct 1 and is used to transport the central flame to the combustion zone (i.e., the combustion section 313). The second end of the central air duct 1 is located within the combustion section 313, which means that after leaving the central air duct 1, the central flame directly enters the combustion section 313, mixes with the biomass pellets, and participates in the combustion process to form a primary air-powder flame.

[0047] Understandably, since the second end of the central air duct 1 is located within the combustion section 313, the central flame can directly enter the combustion zone, which helps maintain the stability of the combustion flame and reduces the risk of flameout.

[0048] In some embodiments, at least a portion of the combustion section 313 and the outlet end of the gas collecting ring 32 are both located within the secondary air duct 33, and the outlet end of the combustion section 313 is located upstream of the outlet end of the gas collecting ring 32.

[0049] It is understandable that, such as Figures 1-4 As shown, at least a portion of the combustion section 313 is located within the secondary air duct 33, allowing the use of air from the secondary air duct 33 to provide additional oxygen, thereby enhancing combustion efficiency. The outlet end of the combustion section 313 is located upstream of the outlet end of the gas collecting ring 32, which helps to create a good airflow organization between the combustion section 313 and the gas collecting ring 32, resulting in a more uniform mixing of natural gas and secondary air.

[0050] In some embodiments, the gas collecting ring 32 includes a gas collecting body 321 and a gas collecting pipe 322. The gas collecting body 321 has a gas collecting inlet, and the gas collecting pipe 322 is connected to the gas collecting body 321. There are multiple gas collecting pipes 322, which are arranged circumferentially at intervals along the axial direction of the primary air duct 31. The outlet end of the gas collecting pipe 322 is located downstream of the outlet end of the combustion section 313.

[0051] Specifically, such as Figures 1-4 As shown, the gas collecting body 321 has a gas collecting inlet for receiving natural gas. The gas collecting pipeline 322 is connected to the gas collecting body 321 and is used to transport natural gas to the combustion zone. There are usually multiple gas collecting pipelines 322, which are arranged circumferentially at intervals along the axial direction of the primary air duct 31.

[0052] Understandably, multiple gas collecting pipes 322 are arranged along the length of the central air duct 1. The multiple gas collecting pipes 322 are arranged at intervals in the circumferential direction, which helps to distribute natural gas evenly in the combustion chamber and ensures the uniformity of the combustion process.

[0053] In some embodiments, the ignition assembly further includes a swirler 23, which is fitted onto the central air gun 22 and is located upstream of the ignition element 21 in the direction of airflow within the central air duct 1.

[0054] It is understandable that, such as Figures 1-4 As shown, the function of the cyclone separator 23 is to create a swirling flow in the airflow, increasing the mixing degree between the airflow and the biomass pellets, thereby improving combustion efficiency. In other words, the natural gas introduced through the central gas gun 22 creates a swirling flow through the cyclone separator 23, which helps to mix the biomass pellets with the airflow and improves combustion efficiency.

[0055] Swirler 23 helps optimize the airflow distribution entering the combustion chamber, ensuring uniformity of the combustion process. By enhancing the mixing effect, it can provide more stable combustion conditions and reduce instability phenomena such as flameout.

[0056] Preferably, the axis of the central air gun 22 coincides with the axis of the second end of the central air duct 1.

[0057] It is understandable that, such as Figures 1-4 As shown, the axis of the central air gun 22 coincides with the axis of the second end of the central air duct 1. This means that the central air gun 22 is inserted along the axial direction of the central air duct 1, and its outlet end is directly upstream of the air outlet 12 of the central air duct 1. This ensures precise alignment of the natural gas flow and the combustion-supporting gas flow, which helps to form a uniform mixture. Precise airflow alignment helps maintain the stability of the combustion process, reduces combustion fluctuations, and prevents flameout.

[0058] In some embodiments, the central air gun 22 further has an exhaust port 221, which is disposed on the side wall of the central air gun 22 and located downstream of the ignition element 21. There are multiple exhaust ports 221, which are arranged circumferentially at intervals along the axis of the central air gun 22.

[0059] It is understandable that, such as Figures 1-4 As shown, exhaust ports 221 are located on the side wall of the central gas gun 22 and downstream of the ignition element 21. Multiple exhaust ports 221 are arranged circumferentially along the axis of the central gas gun 22. This helps to uniformly discharge natural gas, reducing its impact on the combustion process. The uniform distribution of exhaust ports 221 helps maintain the stability of the combustion process, reduces combustion fluctuations, and prevents flameout. Uniform exhaust ensures stable pressure within the combustion chamber, thereby improving combustion efficiency.

[0060] like Figures 1-4 As shown, the natural gas-biomass co-combustion device of this embodiment of the invention also includes a combustion stabilizing tooth 6, which is located at the port of the second end of the primary air duct 31. There are multiple combustion stabilizing teeth 6, which are arranged circumferentially at intervals along the axis of the primary air duct 31.

[0061] Understandably, the flame-stabilizing tooth 6 is located at the port of the second end of the primary air duct 31, that is, at the outlet portion of the primary air duct 31. The flame-stabilizing tooth 6 can stabilize the flame and prevent it from extinguishing, thereby improving the stability of combustion. The design of the flame-stabilizing tooth 6 helps to form a stable flame shape, making the combustion process more uniform.

[0062] In some embodiments, the natural gas-biomass co-combustion device of the present invention further includes a detection component, which includes a first detection unit 51 and a second detection unit 52. The first detection unit 51 is connected to the central air duct 1 to monitor the flame combustion in the central air duct 1. The inlet of the primary air duct 31 is electrically connected to the first detection unit 51. The primary air duct 31 is used to control the opening or closing of the inlet of the primary air duct 31 according to the detection information of the first detection unit 51. The second detection unit 52 is connected to the primary air duct 31 to monitor the flame combustion in the primary air duct 31. The inlet of the secondary air duct 33 and the inlet of the gas collecting ring 32 are both electrically connected to the first detection unit 51. The inlet of the secondary air duct 33 and the inlet of the gas collecting ring 32 are used to sequentially control the opening or closing of the inlet of the secondary air duct 33 and the opening or closing of the inlet of the gas collecting ring 32 according to the detection information of the second detection unit 52.

[0063] Specifically, both the first detection unit 51 and the second detection unit 52 are flame detectors, such as gas flame detectors.

[0064] Understandably, assuming the biomass to be co-combusted is garden waste (using this as an example, including but not limited to agricultural and forestry waste, kitchen waste, and other biomass waste), and has already undergone preliminary drying and crushing with a moisture content controlled below 15% and a calorific value of approximately 3000 kcal, the following steps are taken: During operation, combustion air enters through the air inlet 11 of the central air duct 1. The ignition element 21 first ignites the natural gas ejected from the central air gun 22, generating a central flame. After the first detection unit 51 detects the central flame signal, grinding is used to maintain the particle size at approximately 10 mm, and hot air powder delivery is used to maintain the primary air-powder temperature at approximately 70°C. The primary air-powder airflow (powder concentration approximately 0.2 kg / kg) carrying biomass particles enters through the primary air inlet 41 and rotates. Under centrifugal force, the biomass particles rotate against the wall. The primary air-powder airflow sequentially passes through the air inlet section 311 and the concentration section... After section 312, some biomass pellets gather towards the center of combustion section 313, forming a dense phase gas flow (powder concentration of about 0.4 kg / kg). This gas flow is heated by the central flame and ignited to form a primary air-powder flame. The gas continues forward through the stabilizing tooth 6 to generate backflow, entraining external flue gas to heat itself. After the second detection unit 52 detects the main flame signal, secondary air enters through the inlet of secondary air duct 33. Subsequently, natural gas enters through the inlet of gas collecting ring 32 and is ejected from gas collecting pipeline 322, where it is ignited by the primary air-powder flame to form the outer main flame. At this point, the central flame, the primary air-powder flame, and the outer main flame support each other, and the device is successfully operating.

[0065] In addition, in specific operation of this invention, assuming that no biomass pellets are added, the central gas gun 22 and the ignition element 21 are advanced axially to the vicinity of the stabilizing tooth 6. After the combustion air enters from the air inlet 11 of the central air duct 1, the ignition element 21 first ignites the natural gas sprayed from the central gas gun 22 and generates a central flame. After the first detection unit 51 detects the central flame signal, the secondary air enters from the inlet of the secondary air duct 33. Then, the natural gas enters from the inlet of the gas collecting ring 32 and is sprayed out into the gas collecting pipeline 322 and ignited by the central flame to form the main flame. The second detection unit 52 detects the main flame signal, which indicates that the device is operating successfully.

[0066] Therefore, this invention addresses the issue of co-firing biomass in coal-to-gas boilers. On one hand, it utilizes the high-temperature flame core generated by natural gas combustion to ignite the biomass pellet gas flow, achieving a progressive amplification of ignition energy and ensuring stable combustion under different direct combustion conditions for biomass pellets. On the other hand, co-firing biomass replaces a portion of fossil fuels, enabling clean and low-carbon operation of the boiler. In practical operation, this invention addresses the low-carbonization issue of coal-to-gas boilers by providing a technical route for natural gas-biomass co-firing, leveraging abundant biomass resources. When natural gas supply is scarce or costs are high, a large proportion of biomass co-firing can be achieved with minor modifications; when biomass sources are unstable or natural gas supply is sufficient, it can operate with pure natural gas. This device has wide biomass fuel adaptability, allowing adjustment of biomass pellet size and primary air-coal concentration according to actual conditions. It uses natural gas for stable biomass ignition and combustion, and the overall structure is simple to modify and highly reliable.

[0067] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0069] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0070] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0071] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0072] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A natural gas-biomass co-combustion device, characterized in that, include: A central air duct, which has an air inlet and an air outlet, wherein the air inlet is used to introduce combustion-supporting gas; An ignition assembly includes an ignition element and a central air gun. The central air gun is connected to the central air duct and is movable relative to the central air duct along its axial direction. A first end of the central air gun is used to introduce natural gas, and a second end of the central air gun is located inside the central air duct. The ignition element is located inside the second end of the central air gun and arranged adjacent to the air outlet. The natural gas discharged from the second end of the central air gun is used to mix with the combustion-supporting gas to form a mixture, and the ignition element is used to ignite the mixture. A ventilation duct assembly, comprising a primary ventilation duct, a gas collecting ring, and a secondary ventilation duct, wherein the primary ventilation duct is fitted onto the central ventilation duct, the gas collecting ring is fitted onto the primary ventilation duct, and the secondary ventilation duct is fitted onto the gas collecting ring. The primary ventilation duct is used to introduce an airflow carrying biomass pellets, the gas collecting ring is used to introduce natural gas, and the secondary ventilation duct is used to introduce natural wind.

2. The natural gas-biomass co-combustion device according to claim 1, characterized in that, The primary air duct includes an air intake section, an enrichment section, and a combustion section connected in sequence. The air intake section has a primary air inlet, and the combustion section has a combustion outlet. In the direction of airflow in the primary air duct, the cross-sectional area of ​​the enrichment section gradually decreases.

3. The natural gas-biomass co-combustion device according to claim 2, characterized in that, It also includes a primary air intake duct, which is connected to the intake section. The primary air inlet is located in the primary air intake duct, and the inner wall surface of the primary air intake duct away from the primary air duct is tangent to the inner peripheral wall of the primary air duct.

4. The natural gas-biomass co-combustion device according to claim 2, characterized in that, The air inlet is located at the first end of the central air duct, and the air outlet is located at the second end of the central air duct. The second end of the central air duct is located within the combustion section.

5. The natural gas-biomass co-combustion device according to claim 2, characterized in that, At least a portion of the combustion section and the outlet end of the gas collecting ring are both located inside the secondary air duct, and the outlet end of the combustion section is located upstream of the outlet end of the gas collecting ring.

6. The natural gas-biomass co-combustion device according to claim 5, characterized in that, The gas collecting ring includes a gas collecting body and a gas collecting pipeline. The gas collecting body has a gas collecting inlet. The gas collecting pipeline is connected to the gas collecting body. There are multiple gas collecting pipelines, which are arranged circumferentially at intervals along the axial direction of the primary air duct. The outlet end of the gas collecting pipeline is located downstream of the outlet end of the combustion section.

7. The natural gas-biomass co-combustion device according to claim 1, characterized in that, The ignition assembly also includes a swirler, which is fitted onto the central air gun and is located upstream of the ignition element in the direction of airflow within the central air duct.

8. The natural gas-biomass co-combustion device according to claim 1, characterized in that, The axis of the central air gun coincides with the axis of the second end of the central air duct.

9. The natural gas-biomass co-combustion device according to claim 1, characterized in that, The central air gun also has an exhaust port, which is located on the side wall of the central air gun and downstream of the ignition element. There are multiple exhaust ports, which are arranged circumferentially at intervals along the axis of the central air gun.

10. The natural gas-biomass co-combustion device according to claim 1, characterized in that, It also includes a detection component, which comprises a first detection unit and a second detection unit. The first detection unit is connected to the central air duct for monitoring the flame combustion within the central air duct. The inlet of the primary air duct is electrically connected to the first detection unit. The primary air duct is used to control the opening or closing of its inlet based on the detection information from the first detection unit. The second detection unit is connected to the primary air duct to monitor the flame combustion inside the primary air duct. The inlet of the secondary air duct and the inlet of the gas collecting ring are both electrically connected to the first detection unit. The inlet of the secondary air duct and the inlet of the gas collecting ring are used to control the opening or closing of the inlet of the secondary air duct and the opening or closing of the inlet of the gas collecting ring in sequence according to the detection information of the second detection unit.

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