Combustion system for mixed fuel of hydrogen and fuel gas

Abstract

The invention relates to a combustion system for mixed fuel of hydrogen and fuel gas, a secondary pipeline and a main pipeline are vertically arranged, the secondary pipeline is arranged between a natural gas box body and a combustor, an inlet flow-equalizing mixing device is arranged in the main pipeline, the inlet flow-equalizing mixing device is of a blade structure, and the blade device is arranged on the upstream of the secondary pipeline. The blade structure is provided with a plurality of blades, the connecting line of the two ends of each blade is perpendicular to the central axis direction of the secondary pipeline, the extending direction of each blade is perpendicular to the central axis direction of the secondary pipeline, the distances between the adjacent blades are different, and the farther the distance from the secondary pipeline is, the smaller the distance between the adjacent blades is. According to the combustor capable of directly mixing the fuel, natural gas and hydrogen can be mixed in equal proportion through the arrangement of the distance between the blades, the situation that the proportion of local natural gas and hydrogen is different can be avoided, the combustion efficiency can be improved, and accidents are avoided.

Description

Technical Field

[0001] The present invention relates to the field of combustion technology, in particular to a combustion system of a hydrogen and gas mixed fuel. Background Art

[0002] With the continuous advancement of carbon emission reduction policies worldwide, hydrogen, a high-energy-density gas fuel and a green, clean, and efficient new energy storage medium that does not directly produce pollutants such as carbon compounds, sulfur oxides, and soot during its direct use, is considered one of the most promising clean energy sources. China has officially included hydrogen energy in its energy category and is continuously promoting the development of related industries. The booming development of hydrogen energy is mainly due to its lubricating effect on the transition process of energy structure. Hydrogen energy can effectively absorb the waste electricity generated by renewable energy sources such as wind power, hydropower, and photovoltaic power generation through water electrolysis. This allows the electricity that cannot be connected to the grid to be stored through hydrogen storage and flexibly utilized downstream in the hydrogen energy industry chain.

[0003] Currently, hydrogen is primarily used in the industrial sector as a chemical raw material and gas fuel. Using hydrogen as a fuel through equipment such as fuel cells and burners is a key driver of carbon emission reduction in my country's thermal power industry. However, due to economic constraints, supporting infrastructure development, and related technical bottlenecks, the use of pure hydrogen as a fuel, with the exception of initial commercialization in the mobile transportation sector through proton exchange membrane fuel cells, remains a long way off for deployment in other sectors. Its overall contribution to the decarbonization of the energy structure is very limited. Blending hydrogen into natural gas to form a hydrogen-blended natural gas mixture and then burning it is currently one of the best transitional solutions for hydrogen energy to promote the decarbonization of the energy structure. Existing burners use methods such as spraying to ensure uniform heat exchange and improve heat exchange efficiency, but these structures increase costs and are primarily limited by the inability to adjust specific temperature ranges according to actual needs, resulting in a limited range of applications. Some burners that integrate sophisticated detection instruments such as sensors are expensive, making them inaccessible to widespread use. Furthermore, burners that fail to exchange heat with the liquid can easily cause burns to the user.

[0004] Since hydrogen's physical and chemical properties differ significantly from those of natural gas, as do its combustion parameters such as flammable range, combustion temperature, and combustion speed, using a natural gas burner to directly burn hydrogen can easily lead to combustion instability problems such as thermoacoustic instability and flashback. Furthermore, because hydrogen and natural gas cannot be fully mixed, combustion efficiency is low and combustion is incomplete. Excessive local hydrogen can also create the possibility of deflagration.

[0005] Therefore, based on the above problems, a new combustion system is needed, which can improve the combustion efficiency by fully mixing hydrogen and natural gas, reduce carbon monoxide emissions, and avoid danger. Summary of the Invention

[0006] In view of the above problems, the present invention provides a combustion system of a hydrogen and natural gas mixed fuel, thereby improving combustion efficiency.

[0007] To achieve the above objectives, the present invention adopts the following technical solutions:

[0008] A combustion system for a mixture of hydrogen and natural gas comprises a natural gas tank, a hydrogen production device, a hydrogen tank and a burner. The hydrogen produced by the hydrogen production device is transported to the hydrogen tank. The natural gas tank is connected to the burner via a main pipeline. The hydrogen tank is connected to the main pipeline via a secondary pipeline. Natural gas and hydrogen are mixed in the main pipeline to form a mixed fuel, which is then transported to the burner via the main pipeline. The system is characterized in that the secondary pipeline is vertically connected to the main pipeline, the connection position between the secondary pipeline and the main pipeline is arranged between the natural gas tank and the burner, and a uniform proportion mixing device is arranged in the main pipeline. The uniform proportion mixing device is a blade structure and is arranged upstream of the connection position. The blade structure is provided with a plurality of blades. The extension direction of the gap between adjacent blades is arranged perpendicular to the central axis direction of the secondary pipeline. The spacing between adjacent blades is different. As the distance from the secondary pipeline increases, the spacing between adjacent blades becomes smaller and smaller.

[0009] As an improvement, the spacing between adjacent blades becomes smaller and smaller as the distance from the secondary pipe increases.

[0010] As an improvement, a flow balancing device is provided downstream of the main pipeline at the connection point between the main pipeline and the secondary pipeline. The flow balancing device is a blade structure. The blade structure is provided with multiple blades, and the extension direction of the gap between adjacent blades is provided parallel to the central axis direction of the secondary pipeline.

[0011] As an improvement, a mixing device is provided downstream of the flow balancing device. The mixing device is a blade structure. The blade structure includes a plurality of blades, and adjacent blades are split-open adjustment structures.

[0012] As an improvement, multiple mixing devices are provided, and the mixing mechanism includes a parallel structure in which the extension direction of the gap between adjacent blades is parallel to the direction of the central axis of the secondary pipe, and a vertical structure in which the extension direction of the gap between adjacent blades is perpendicular to the direction of the central axis of the secondary pipe. The parallel structure and the vertical structure are arranged alternately.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1) Based on the existing burners, a fully mixed even-proportion mixing burner system is creatively proposed. By setting blades on the pipe where hydrogen and gas are mixed and setting the spacing between the blades, natural gas and hydrogen can be mixed in equal proportions, which can avoid local differences in the proportion of natural gas and hydrogen, improve combustion efficiency, and avoid accidents.

[0015] 2) Based on existing burners, a hybrid burner system with flow regulation, rectification, and equalization functions has been creatively proposed. This system includes upstream and downstream proportional mixing devices and a flow equalization mixing device, enabling dual control and equalization. This addresses the problem of uneven inlet flow velocity at its source, resulting in significant equalization, improving the accuracy and stability of inlet flow and temperature measurements, and thereby enhancing the economy and stability of the combustion system. Furthermore, this device has a simple structure, avoiding the excessive pressure drop and increased operating costs associated with the additional installation of a flow equalization mixing device in the prior art, resulting in high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the system structure of the present invention;

[0017] Figure 2 Schematic diagram of the burner mixing structure of the present invention;

[0018] Figure 3 A partial three-dimensional structural diagram of a hybrid burner provided by the present invention is shown;

[0019] Figure 4 A second schematic diagram of a partial three-dimensional structure of a hybrid burner provided by the present invention is shown;

[0020] Figure 5 A third schematic diagram of a partial three-dimensional structure of a hybrid burner provided by the present invention is shown;

[0021] Figure 6 The split blade structure of the present invention is shown. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be supplemented below with reference to the accompanying drawings in the embodiments of the present invention.

[0023] Figure 1-6 The schematic diagram of the structure of the hybrid burner of the present invention is shown. Figure 1 As shown, a combustion system for a hydrogen and gas mixed fuel includes a natural gas tank, a hydrogen production device, a hydrogen tank and a burner 3. The hydrogen produced by the hydrogen production device is transported to the hydrogen tank. The natural gas tank is connected to the burner 3 through a main pipeline 1, and the hydrogen tank is connected to the main pipeline through a secondary pipeline 2. Natural gas and hydrogen are mixed in the main pipeline 1 to form a mixed fuel, which is then transported to the burner 3 through the main pipeline.

[0024] like Figure 2 As shown, the secondary pipeline 2 is arranged vertically with the main pipeline 1, and the secondary pipeline 2 is arranged between the natural gas tank and the burner 3. The main pipeline 1 is provided with a uniform mixing device 4, and the uniform mixing device 4 is arranged upstream of the connection position between the secondary pipeline and the main pipeline; Figure 3 As shown, the uniform mixing device 4 is a blade structure, and the blade structure is provided with a plurality of blades, and the extension direction of the gap between adjacent blades is perpendicular to the central axis direction of the secondary pipe.

[0025] As an improvement, the spacing between adjacent blades varies, decreasing with distance from the secondary pipeline. Near the hydrogen outlet, the hydrogen flow rate is highest, and mixing of hydrogen and natural gas is optimal. This results in uneven mixing overall. As the distance from the outlet increases, hydrogen flow decreases, and mixing worsens, resulting in poor overall mixing. By adjusting the gap size, the present invention reduces the natural gas flow rate along the direction of hydrogen entering the natural gas pipeline, resulting in balanced mixing across the entire area and an overall more uniform natural gas-hydrogen ratio.

[0026] As the distance from the secondary pipeline increases, the gap between adjacent blades becomes smaller and smaller. The above setting can further ensure the mixing balance of the entire area and improve the overall uniformity of the mixed natural gas and hydrogen ratio.

[0027] The main pipeline is provided with a fuel flow balancing device 5, and the flow balancing mixing adjustment device 5 is located downstream of the connection position between the secondary pipeline and the main pipeline; a hydrogen flow balancing device 6 is provided on the secondary pipeline 2, and the secondary pipeline 2 is provided on the pipeline between the inlet equalizing proportion mixing device 4 and the flow balancing device 5, and the equalizing proportion mixing device 4 and the flow balancing device 5 are multi-blade structures.

[0028] like Figure 5 As shown, the blades are inclined structures, and the inclination angles of adjacent blades of the proportional mixing device 4 are different. As the distance from the secondary pipeline increases, the angle between the blade swing direction and the central axis of the secondary pipeline becomes smaller and smaller. The angle is the angle between the central axis of the secondary pipeline in the direction of hydrogen flow and the inclination direction of the blade.

[0029] Near the hydrogen outlet, the hydrogen flow rate is the highest, and the mixing of hydrogen and natural gas is optimal. This results in uneven mixing overall. As the distance from the outlet increases, the hydrogen flow rate decreases, and the mixing becomes worse, resulting in poor overall mixing. The present invention improves the blade angle so that the natural gas flow rate decreases along the direction in which the hydrogen enters the natural gas pipeline, resulting in balanced mixing across the entire area and improved overall mixing uniformity.

[0030] Based on the existing burner, the present invention creatively proposes an inlet flow regulation system with flow regulation function and also has the functions of equalizing proportion, rectifying and equalizing flow. It includes two upstream and downstream split regulating devices to realize dual control and dual equalizing flow, which has a significant equalizing effect on the proportion of natural gas and hydrogen and has high economic benefits.

[0031] Preferably, as the distance from the secondary pipe increases, the angle between the blade and the liquid flow direction in the direction of the secondary pipe center axis becomes smaller and smaller, and the amplitude thereof increases continuously. By changing the amplitude of the angle, the effect of balancing the proportions can be better improved, and overall mixing can be more uniform.

[0032] Although the above method can ensure that natural gas and hydrogen are mixed in a sufficient proportion and avoid excessive natural gas or hydrogen in some areas, which may cause hydrogen explosion, it will lead to uneven distribution of fuel in the main pipeline, resulting in more fuel near the hydrogen pipeline and less fuel far away from the hydrogen pipeline. In order to ensure uniform fuel distribution throughout the pipeline, the following improvements have been made:

[0033] Preferably, Figure 3 As shown, a flow equalizer 5 is installed downstream of the main pipeline connecting the main and secondary pipelines. This flow equalizer and mixer is a vane structure with multiple blades. As an improvement, the distance between the fuel channels of adjacent blades increases as they are farther from the secondary pipeline. This arrangement allows the fuel to flow as far away from the secondary pipeline as possible, thereby improving the concentration of the mixed fuel near the secondary pipeline and ensuring that the fuel is evenly distributed throughout the main pipeline.

[0034] As an improvement, the distance between the fuel channels of adjacent blades further from the secondary pipe becomes larger and larger. The above arrangement can further distribute the fuel evenly throughout the main pipe.

[0035] As an improvement, Figure 3 As shown, the extending direction of the gap between adjacent blades of the flow balancing device 5 is perpendicular to the central axis direction of the secondary pipeline (the flow channel directions of the devices 4 and 5 are parallel).

[0036] As an improvement, Figure 4 As shown, the gaps between adjacent blades of flow equalizer 5 extend parallel to the central axis of the secondary pipe. When the flow equalizer is partially open, each set of two opposing blades can divert the flow in opposite directions. The equalizing mixing device 4 diffuses the flow horizontally, while the equalizing device 5 diffuses the flow vertically. When the equalizing mixing devices 4 and 5 are combined, the two sets of regulating devices are perpendicular to each other, allowing for flow diffusion in all four directions, both horizontally and vertically, achieving a higher degree of uniformity.

[0037] Preferably, the blades can adjust their angles and the spacing between adjacent blades to control the flow of the fluid.

[0038] Based on the existing burner, the present invention creatively proposes an inlet flow regulation system that has the functions of flow regulation and also has the functions of equalizing proportions, rectifying and equalizing flow. It includes two upstream and downstream devices to achieve dual control and dual equalization, which significantly improves the equalization effect of natural gas and hydrogen, and subsequently, the equalization device is used to evenly distribute the gas throughout the pipeline. The combination of the above two devices can achieve flow control, uniform proportional distribution, and uniform fuel distribution throughout the pipeline. Preferably, the mixing device 6 provided downstream of the equalization device 5 is a blade structure, which includes a plurality of blades, and adjacent blades are split adjustment structures.

[0039] Preferably, multiple mixing devices 6 can be provided, with the mixing mechanism blades comprising a parallel structure arranged parallel to the central axis of the secondary pipe and a vertical structure arranged perpendicular to the central axis of the secondary pipe, with the parallel and vertical structures arranged alternately. When the mixing devices with different orientations are combined, the two sets of regulating devices are perpendicular to each other, allowing the flow to be diffused in all four directions, both horizontally and vertically, achieving a higher degree of homogenization.

[0040] Preferably, the adjacent blades are a split adjustment structure, such as Figure 6 shown.

[0041] The flow of natural gas needs to be controlled. The split-type regulating device of the present invention has both flow balancing and flow regulating functions.

[0042] Preferably, a hydrogen flow equalizing device 6 is provided on the hydrogen pipeline, and the flow equalizing device 6 is a multi-blade structure, wherein adjacent blades are split and adjusted. By providing the split and adjusted structure, the input hydrogen can be made uniform.

[0043] Preferably, the equalizing mixing device 4, the hydrogen equalizing flow device 6, and the fuel equalizing flow device 5 are independently adjustable. Different device openings result in different flow resistances and different equalizing mixing effects. When the equipment can withstand greater flow resistance, a smaller device opening can be used to achieve better equalizing mixing effects.

[0044] As an improvement, the even-proportion mixing device 4 is positioned near the connection point between the secondary and primary pipelines, preferably 1-2 mm from the most upstream point of the connection point. By positioning both the even-proportion mixing device 4 and the hydrogen equalizing device 6 near the connection point, the natural gas and hydrogen can be more accurately distributed according to the initial distribution of the blades. This allows the gas distributed by the even-proportion mixing device 4 to become more accurate with distance from the secondary pipeline, thereby achieving more accurate overall equal-proportion distribution.

[0045] As an improvement, the hydrogen flow equalization device 6 is placed near the secondary pipe and the main pipe, preferably 1-2 mm away from the connection point between the secondary pipe and the main pipe. This ensures that the hydrogen is evenly distributed in accordance with the initial distribution state and can cooperate with the equalizing mixing device 4 near the connection point to achieve a more even mixing ratio.

[0046] When the blade angle (e.g. Figure 6 When angle B) is small (approaching a closed state), flow resistance is high; conversely, when the blade angle is large (approaching an open state), flow resistance is low. If the flow velocity is high in a certain area, the nearby blades should be adjusted to a smaller angle (approaching a closed state), which can induce fuel to flow toward the area with the larger blade angle, thus achieving a flow equalization effect. If the flow velocity is low in a certain area, the nearby blades should be adjusted to a smaller angle (approaching a closed state), which can induce fuel to flow toward the area with the larger blade angle, thus achieving a flow equalization effect. If all blades have the same angle, flow equalization can still be achieved, but the effect will be less effective. By adjusting the angles as described above, the optimal flow equalization effect can be achieved with minimal resistance.

[0047] As an improvement, the angle between adjacent opposing blades of the uniform mixing device 4 decreases as the distance from the secondary pipeline to the primary pipeline connection (where the secondary pipeline enters the primary pipeline) increases. By improving the angle of the opposing blades, the present invention reduces the natural gas flow rate along the direction of hydrogen entering the gas channel, aligning it with the hydrogen flow rate. This ensures a substantially consistent local ratio of natural gas to hydrogen, improving the overall mixing effect.

[0048] Preferably, as the distance from the secondary pipe to the main pipe connection position gets closer, the angle between the blades of the evenly proportioned mixing device 4 becomes smaller and smaller, and the amplitude thereof increases continuously. By changing the amplitude of the angle, the evenly proportioned mixing effect can be better improved.

[0049] As an improvement, the distribution density of the blades in the uniform mixing device 4 decreases as the distance from the hydrogen pipe increases. As the distance from the inlet increases, the hydrogen flow rate decreases. By improving the blade distribution density, the present invention adjusts the blade distribution density along the direction of the hydrogen entering the waterway, adapting to the hydrogen flow rate. This ensures that the local ratio of natural gas to hydrogen is essentially the same, improving the overall mixing effect.

[0050] As a preference, as the distance from the secondary pipe to the main pipe connection position gets closer, the distribution density of the blades of the uniform mixing device 4 becomes smaller and smaller, and the amplitude increases continuously. By changing the amplitude of the distribution density, the heat exchange effect can be better improved, and the overall heat exchange can be more uniform.

[0051] Preferably, multiple mixing devices 6 are provided, and the angles between adjacent blades in the mixing device become smaller and smaller along the flow direction of the fuel in the main pipeline. By varying the amplitude, on the one hand, the flow distribution can be further uniformed while keeping the flow resistance low.

[0052] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A combustion system for a hydrogen and gas mixed fuel, comprising a natural gas tank, a hydrogen production device, a hydrogen tank, and a burner. The hydrogen produced by the hydrogen production device is transported to the hydrogen tank, the natural gas tank is connected to the burner via a main pipeline, and the hydrogen tank is connected to the main pipeline via a secondary pipeline. Natural gas and hydrogen are mixed in the main pipeline to form a mixed fuel, which is then transported to the burner via the main pipeline. The system is characterized in that: The secondary pipeline is vertically connected to the main pipeline. The connection position of the secondary pipeline and the main pipeline is set between the natural gas tank and the burner. A uniform proportion mixing device is set in the main pipeline. The uniform proportion mixing device is a blade structure and is set upstream of the connection position. The blade structure is provided with multiple blades. The extension direction of the gap between adjacent blades is set perpendicular to the central axis direction of the secondary pipeline. The spacing between adjacent blades is different. As the distance from the secondary pipeline increases, the spacing between adjacent blades becomes smaller and smaller.

2. The combustion system according to claim 1, wherein: As the distance from the secondary pipe increases, the spacing between adjacent blades becomes smaller and smaller.

3. The combustion system according to claim 1, wherein: A flow balancing device is provided downstream of the main pipeline at the connection position between the main pipeline and the secondary pipeline. The flow balancing device is a blade structure. The blade structure is provided with multiple blades, and the extension direction of the gap between adjacent blades is provided parallel to the central axis direction of the secondary pipeline.

4. The combustion system according to claim 3, wherein: In the flow balancing device, the distance between the fuel channels between adjacent blades that are farther from the secondary pipe is larger.

5. The combustion system according to claim 3, wherein: A mixing device is provided downstream of the flow balancing device. The mixing device is a blade structure. The blade structure includes a plurality of blades, and adjacent blades are in a split adjustment structure.

6. The combustion system according to claim 5, wherein: Multiple mixing devices are provided, and the mixing mechanism includes a parallel structure in which the extension direction of the gap between adjacent blades is parallel to the central axis direction of the secondary pipeline, and a vertical structure in which the extension direction of the gap between adjacent blades is perpendicular to the central axis direction of the secondary pipeline. The parallel structure and the vertical structure are alternately provided.

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