A combustion system for a mixture of hydrogen and gas fuel

Abstract

This invention relates to a combustion system for a hydrogen and gas mixture. A secondary pipeline is perpendicular to the main pipeline and positioned between the natural gas tank and the burner. An inlet flow equalization mixing device, which is a blade structure, is installed upstream of the secondary pipeline. The blade structure comprises multiple blades, with the line connecting the two ends of each blade perpendicular to the central axis of the secondary pipeline. The extension direction of each blade is also perpendicular to the central axis of the secondary pipeline. The spacing between adjacent blades varies, decreasing with increasing distance from the secondary pipeline. This invention provides a burner for direct fuel mixing. By adjusting the blade spacing, natural gas and hydrogen can be mixed in equal proportions, avoiding uneven local proportions and improving combustion efficiency, thus preventing accidents.

Description

Technical Field

[0001] This invention relates to the field of combustion technology, and more specifically to a combustion system for a mixture of hydrogen and gas fuel. Background Technology

[0002] With the continuous advancement of global carbon emission reduction policies, hydrogen, as a high-energy-density gaseous 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 utilization, is considered one of the most promising clean energy sources today. China has officially included hydrogen energy in its energy category and is continuously promoting the development of related industries. The rapid development of hydrogen energy is mainly due to its lubricating effect on the transition process of the energy structure. Hydrogen energy can effectively absorb the abandoned electricity generated by renewable energy sources such as wind power, hydropower, and photovoltaic power through water electrolysis, thereby storing the electricity that cannot be connected to the grid through hydrogen storage and flexibly utilizing it downstream in the hydrogen energy industry chain.

[0003] Currently, hydrogen is mainly used in the industrial sector as a chemical raw material and gaseous fuel. Its utilization as fuel in fuel cells and burners is a significant driver of carbon emission reduction in my country's thermal power industry. However, due to economic constraints, limitations in infrastructure development, and related technological bottlenecks, the use of pure hydrogen as fuel, apart from its initial commercialization in the mobile transportation sector through proton exchange membrane fuel cells, requires considerable time for further development and utilization in other fields. Overall, its contribution to the low-carbon transformation of the energy structure is quite limited. Blending hydrogen with natural gas to form a hydrogen-blended natural gas mixture and then burning it is one of the best transitional solutions for promoting the low-carbon transformation of the energy structure using hydrogen energy. Existing burners employ spraying and other methods to achieve uniform heat exchange and improve efficiency, but their structure increases costs. They also suffer from limitations in temperature control, restricting their application. Some burners integrating sensors and other precision detection instruments are too expensive to be widely used. Furthermore, burner malfunctions, preventing heat exchange with the liquid, can easily lead to burns for users.

[0004] Because the physicochemical properties of hydrogen differ significantly from those of natural gas, and because hydrogen's flammability range, combustion temperature, combustion rate, and other combustion characteristic parameters differ significantly from those of natural gas, directly burning hydrogen in a natural gas burner can easily lead to combustion instability problems such as thermoacoustic instability and backfire. At the same time, because hydrogen and natural gas cannot be fully mixed, combustion efficiency is low and combustion is incomplete, and excessive local hydrogen may also cause deflagration.

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

[0006] To address the aforementioned problems, this invention provides a combustion system for a mixture of hydrogen and gas fuel, thereby improving combustion efficiency.

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

[0008] A combustion system for a hydrogen and gas mixture includes a natural gas tank, a hydrogen production unit, a hydrogen tank, and a burner. Hydrogen produced by the hydrogen production unit is delivered 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 delivered to the burner via the main pipeline. The system is characterized in that the secondary pipeline is perpendicularly connected to the main pipeline, and the connection point between the secondary pipeline and the main pipeline is located between the natural gas tank and the burner. A proportional mixing device, which is a blade structure, is installed in the main pipeline upstream of the connection point. The blade structure has multiple blades, and the direction of the gap between adjacent blades is perpendicular to the central axis of the secondary pipeline. The spacing between adjacent blades varies, decreasing with increasing distance from the secondary pipeline.

[0009] As an improvement, the magnitude of the decreasing spacing between adjacent blades increases with the distance from the secondary pipe.

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

[0011] As an improvement, a mixing device is provided downstream of the flow equalization device. The mixing device is a blade structure, which includes multiple blades, with adjacent blades forming a split-adjustment structure.

[0012] As an improvement, multiple mixing devices are provided. 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 existing burners, a creatively proposed uniform proportioning burner system with full mixing is proposed. By setting blades on the pipeline for mixing hydrogen and gas, and by setting the spacing of the blades, natural gas and hydrogen can be mixed in equal proportions. This can avoid local differences in the ratio of natural gas and hydrogen, improve combustion efficiency, and avoid accidents.

[0015] 2) Based on existing burners, a novel hybrid burner system with flow regulation, rectification, and flow equalization functions is proposed. This system includes upstream and downstream proportional mixing devices and flow equalization mixing devices, enabling dual control and dual flow equalization. It addresses the problem at its source—uneven inlet flow velocity—resulting in significant flow equalization. This improves the accuracy and stability of inlet flow and temperature measurements, thereby enhancing the economy and stability of the combustion system. Furthermore, the device has a simple structure, avoiding the excessive pressure drop and increased operating costs associated with the additional flow equalization mixing devices in existing technologies, thus offering high economic benefits. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the system structure of the present invention;

[0017] Figure 2 This is a schematic diagram of the combustion structure of the burner of the present invention;

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

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

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

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

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

[0023] Figure 1-6 A schematic diagram of the hybrid burner structure of the present invention is shown. Figure 1 As shown, a combustion system for a hydrogen and gas mixture 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. 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 installed perpendicular to the main pipeline 1, and is located between the natural gas tank and the burner 3. A proportioning mixing device 4 is installed in the main pipeline 1, and is located upstream of the connection point between the secondary pipeline and the main pipeline. Figure 3 As shown, the uniform mixing device 4 is a blade structure with multiple blades, and the extension direction of the gap between adjacent blades is perpendicular to the central axis 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, resulting in optimal mixing of hydrogen and natural gas. However, this leads to uneven mixing overall. Further away from the outlet, hydrogen levels decrease, further worsening the mixing and ultimately resulting in poor overall mixing. This invention addresses this by improving the gap size, ensuring that the natural gas flow rate decreases along the direction of the hydrogen-to-natural-gas pipeline, leading to more balanced mixing throughout the region and improving the overall uniformity of the mixed natural gas-hydrogen ratio.

[0026] As the distance from the secondary pipeline increases, the gap between adjacent blades decreases at an increasingly larger rate. This configuration further ensures balanced mixing throughout the region, improving the overall uniformity of the hydrogen-to-natural gas mixture.

[0027] The main pipeline is equipped with a fuel flow equalization device 5, and the flow equalization and mixing regulating device 5 is located downstream of the connection between the secondary pipeline and the main pipeline; a hydrogen flow equalization device 6 is installed on the secondary pipeline 2, which is located on the pipeline between the inlet proportional mixing device 4 and the flow equalization device 5. The proportional mixing device 4 and the flow equalization device 5 are multi-blade structures.

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

[0029] Near the hydrogen outlet, the hydrogen flow rate is at its maximum, resulting in the best mixing of hydrogen and natural gas. However, this leads to uneven mixing overall. As the distance from the outlet increases, the amount of hydrogen decreases, further worsening the mixing and ultimately leading to poor overall mixing. This invention addresses this by improving the blade angle, causing the natural gas flow rate to decrease gradually along the direction of the hydrogen-to-natural-gas pipeline, resulting in more balanced mixing throughout the entire area and improved overall mixing uniformity.

[0030] Based on existing burners, this invention creatively proposes an inlet flow regulation system that not only regulates flow but also provides equalization, rectification, and flow equalization functions. It includes two opposing regulating devices at the upstream and downstream ends, enabling dual control and dual flow equalization. This results in a significant equalization effect for natural gas and hydrogen, and offers high economic benefits.

[0031] Preferably, the angle between the blade and the liquid flow direction along the central axis of the secondary pipe decreases with increasing distance from the secondary pipe. This variation in angle improves the mixing ratio and achieves better overall uniformity.

[0032] While the above method ensures a thorough and even mixing of natural gas and hydrogen, preventing localized overfilling of either gas or hydrogen and the resulting hydrogen explosion, it leads to uneven fuel distribution within the main pipeline. This results in more fuel near the hydrogen pipe and less further away. To ensure a more uniform fuel distribution throughout the pipeline, the following improvements were implemented:

[0033] Preferred, such as Figure 3 As shown, a flow equalization device 5 is installed downstream of the main pipeline, which connects the main pipeline and the secondary pipeline. This flow equalization and mixing device has a blade structure with multiple blades. As an improvement, the fuel channel spacing between adjacent blades farther from the secondary pipeline is larger. This arrangement allows the fuel to flow as far away from the secondary pipeline as possible, thus improving the situation where the mixed fuel is concentrated near the secondary pipeline, resulting in a more even distribution of fuel throughout the main pipeline.

[0034] As an improvement, the spacing between fuel channels between adjacent blades farther from the secondary pipeline gradually increases. This configuration further ensures more even fuel distribution throughout the main pipeline.

[0035] As an improvement, such as Figure 3 As shown, the extension direction of the gap between adjacent blades of the flow equalization device 5 is set perpendicular to the direction of the central axis of the secondary pipe (the flow paths of devices 4 and 5 are parallel).

[0036] As an improvement, such as Figure 4 As shown, the extension direction of the gap between adjacent blades of the flow equalization device 5 is parallel to the direction of the central axis of the secondary pipe. When the flow equalization mixing device is partially open, the two opposing blades in each group can guide the flow to both sides. The flow equalization and proportioning mixing device 4 can diffuse the flow velocity in the horizontal direction, and the flow equalization device 5 can diffuse the flow velocity in the vertical direction. After the flow equalization and proportioning mixing devices 4 and 5 are combined, since the two sets of regulating devices are perpendicular to each other, the flow can be diffused in all four directions, both horizontally and vertically, resulting in a higher degree of homogenization.

[0037] Preferably, the blades can be angled and the spacing between adjacent blades can be adjusted to control the fluid flow rate.

[0038] This invention, based on existing burners, creatively proposes an inlet flow regulation system that not only regulates flow but also provides proportional, rectification, and flow equalization functions. It includes upstream and downstream devices for dual control and dual flow equalization, resulting in a significant proportional equalization effect between natural gas and hydrogen. Furthermore, the flow equalization device ensures uniform distribution throughout the pipeline. The cooperation of these two devices achieves flow control, uniform proportional distribution, and uniform fuel distribution throughout the pipeline. Preferably, a mixing device 6 is located downstream of the flow equalization device 5. This mixing device has a blade structure, comprising multiple blades, with adjacent blades forming a counter-adjustable structure.

[0039] Preferably, multiple mixing devices 6 can be provided. The mixing mechanism blades include parallel structures arranged parallel to the central axis of the secondary pipe and vertical structures arranged perpendicular to the central axis of the secondary pipe, with the parallel and vertical structures alternating. After the mixing devices in different directions are combined, since the two sets of regulating devices are perpendicular to each other, the flow can be diffused in all four directions, both horizontally and vertically, resulting in a higher degree of homogenization.

[0040] Preferably, the adjacent blades are a split-opening adjustable structure, such as... Figure 6 As shown.

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

[0042] Preferably, a hydrogen flow equalization device 6 is installed on the hydrogen pipeline. The flow equalization device 6 has a multi-blade structure, and the adjacent blades have a split-adjustment structure. By setting the split-adjustment structure, the input hydrogen can be made uniform.

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

[0044] As an improvement, the equalization and proportioning mixing device 4 is positioned near the connection point between the secondary pipeline and the main pipeline, preferably 1-2 mm upstream of the connection point. By positioning both the equalization and proportioning mixing device 4 and the hydrogen equalization and proportioning device 6 close to the connection point, the natural gas and hydrogen can be more accurately distributed according to the initial distribution through the blades. This allows the gas distributed by the equalization and proportioning mixing device 4 to be more precise depending on the distance from the secondary pipeline, resulting in a more accurate overall equalization and proportioning distribution.

[0045] As an improvement, the hydrogen equalization device 6 is positioned on the secondary pipeline near the main pipeline, preferably 1-2 mm from the connection point between the secondary and main pipelines. This ensures that the hydrogen is evenly distributed in accordance with the initial distribution state, and allows it to work in conjunction with the proportional mixing device 4 located near the connection point to further ensure a more even mixing ratio.

[0046] When the blade angle (e.g.) Figure 6 When the blade angle (B) is small (approaching a closed state), the flow resistance is high; conversely, when the blade angle is large (approaching an open state), the flow resistance is low. If the flow velocity is high at a certain point, the nearby blades should be adjusted to a smaller angle (approaching a closed state) to induce fuel to flow towards the area with the larger blade angle, achieving a flow equalization effect. If the flow velocity is low at a certain point, the nearby blades should be adjusted to a smaller angle (approaching a closed state) to induce fuel to flow towards the area with the larger blade angle, achieving a flow equalization effect. If all blade angles are the same, although a flow equalization effect can still be achieved, the effect is less pronounced. 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 proportional mixing device 4 decreases as the distance to the connection point between the secondary and main pipelines (the inlet where the secondary pipeline enters the main pipeline) decreases. This invention improves the angle between the opposing blades so that the natural gas flow rate decreases along the direction of hydrogen entry into the gas combustion channel, adapting to the hydrogen flow rate and ensuring a relatively uniform local ratio of natural gas to hydrogen, thus improving the overall mixing effect.

[0048] Preferably, as the distance to the connection point between the secondary and main pipes increases, the angle between the two blades of the proportional mixing device 4 gradually decreases. This variation in the angle enhances the proportional mixing effect.

[0049] As an improvement, the distribution density of the blades in the proportional mixing device 4 decreases as the distance to the hydrogen pipe decreases. Conversely, the hydrogen flow rate decreases as the distance to the inlet increases. This invention improves the blade distribution density so that the density varies along the direction of the hydrogen inlet channel, adapting to the hydrogen flow rate, resulting in a more uniform local ratio of natural gas to hydrogen and thus improving the overall mixing effect.

[0050] Preferably, the distribution density of the blades in the proportional mixing device increases with the distance from the connection point between the secondary and main pipes. This variation in distribution density improves heat exchange efficiency and achieves greater overall heat uniformity.

[0051] Preferably, multiple mixing devices 6 are provided, and the angle between adjacent blades in the mixing device gradually decreases along the flow direction of the fuel in the main pipeline. By varying the amplitude, on the one hand, it is possible to ensure a lower flow resistance and on the other hand, to further ensure a uniform flow distribution.

[0052] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A combustion system for a hydrogen and gas mixture, comprising a natural gas tank, a hydrogen production unit, a hydrogen tank, and a burner, wherein hydrogen produced by the hydrogen production unit is supplied 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 supplied to the burner via the main pipeline; characterized in that, The secondary pipeline is perpendicularly connected to the main pipeline. The connection point between the secondary pipeline and the main pipeline is located between the natural gas tank and the burner. A proportional mixing device is installed in the main pipeline. The proportional mixing device is a blade structure and is located upstream of the connection point. The blade structure has multiple blades. The direction of the gap between adjacent blades is perpendicular to the central axis of the secondary pipeline. The spacing between adjacent blades is different. As the distance from the secondary pipeline increases, the spacing between adjacent blades decreases.

2. The combustion system as described in claim 1, characterized in that, As the distance from the secondary pipe increases, the magnitude of the decreasing spacing between adjacent blades continues to increase.

3. The combustion system as described in claim 1, characterized in that, A flow equalization device is installed downstream of the main pipeline at the connection point between the main pipeline and the secondary pipeline. The flow equalization device is a blade structure with multiple blades. The direction of the gap between adjacent blades is parallel to the central axis of the secondary pipeline.

4. The combustion system as described in claim 3, characterized in that, In a flow equalization device, the channel spacing between adjacent blades that are farther away from the secondary pipe is larger.

5. The combustion system as described in claim 3, characterized in that, A mixing device is installed downstream of the flow equalization device. The mixing device is a blade structure, which includes multiple blades, with adjacent blades forming a split-adjustment structure.

6. The combustion system as described in claim 5, characterized in that, Multiple mixing devices are provided. 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.

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