Hydrogen blending facility for natural gas pipeline

Abstract

The present invention relates to a technology that entrains hydrogen into a natural gas pipe network and thus transports the natural gas blended with the hydrogen, and the hydrogen blending facility for a natural gas pipeline.

Description

HYDROGEN BLENDING FACILITY FOR NATURAL GAS PIPELINE

[0001] The present invention relates to a technology that entrains hydrogen into a natural gas pipe network and thus transports the natural gas blended with the hydrogen, more particularly to a facility that is capable of blending hydrogen and natural gas uniformly using an existing natural gas pipe, keeping the flow of blended gas of hydrogen and natural gas stably, and optimizing a ratio of hydrogen to natural gas of the blended gas, thereby allowing the blended gas to be fed safely and stably.

[0002] There have been consistent efforts to reduce carbon emissions globally, and hydrogen has emerged as a key resource for future energy transition. Hydrogen is a clean energy source that does not emit greenhouse gases like carbon dioxide when burnt and thus contributes to the achievement of carbon neutrality targets. However, a substantial amount of time and cost is required in newly building hydrogen feed infrastructure, which undesirably makes it hard to expand initial markets for the hydrogen feed infrastructure.

[0003] To solve such problems, a method for entraining hydrogen into an existing natural gas pipe network has been in the limelight. The natural gas pipe network has been already built widely, and therefore, hydrogen feed is achieved using the existing natural gas pipe network, without any investment in large-scale hydrogen infrastructure. As a result, the technology that blends hydrogen and natural gas is evaluated as an economical and efficient method that is capable of reducing carbon emissions, while efficiently utilizing the existing infrastructure.

[0004] Because hydrogen and natural gas have different physical properties from each other, however, technological problems may occur in a process of blending them. Hydrogen is a smaller molecule than natural gas and has a faster diffusion speed than natural gas, thereby causing unbalancing of a blending ratio or occurrence of flow instability. This results in changes in pressure of a pipe, a decrease in a quality of blending gas, reduction in energy transport efficiency, etc. To solve such problems, therefore, there is a need to develop a method for effectively blending hydrogen and natural gas with each other.

[0005] To satisfy such requirements, therefore, the present invention provides a hydrogen blending facility for a natural gas pipeline that is capable of uniformly keeping a blending ratio of natural gas to hydrogen, optimizing the flow in a pipe, and preventing flow instability from occurring. This maximizes the stability and efficiency of blended gas and expands hydrogen feed infrastructure using the existing natural gas pipe network.

[0006] Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the related art, and it is an object of the present invention to provide a facility that is capable of blending hydrogen and natural gas uniformly in a process where the hydrogen is entrained into a natural gas pipe and transported with the natural gas, keeping the flow of blended gas stably, and optimizing a ratio of hydrogen to natural gas of the blended gas.

[0007] To accomplish the above-mentioned object, according to the present invention, there is provided a hydrogen blending facility for a natural gas pipeline, including: a main pipe for transporting natural gas; and a plurality of injection pipes connected to the main pipe to inject hydrogen into the main pipe, wherein the main pipe has a plurality of hydrogen injection holes formed thereon in such a way as to be connected correspondingly to the plurality of injection pipes, and the plurality of hydrogen injection holes are spaced apart from one another at given intervals on the main pipe in a moving direction of the natural gas, the plurality of injection pipes having a first injection pipe connected to a first hydrogen injection hole of the plurality of hydrogen injection holes in such a way as to have a first angle and a second injection pipe connected to a second hydrogen injection hole of the plurality of hydrogen injection holes in such a way as to have a second angle different from the first angle.

[0008] According to the embodiment of the present invention, the plurality of hydrogen injection holes may be formed along the outer periphery of the main pipe in different directions of the main pipe in such a way as to have given angles with respect to the main pipe.

[0009] According to the embodiment of the present invention, if the hydrogen injection hole corresponding to the injection pipe is located on the underside of the main pipe, the corresponding injection pipe may be connected to the main pipe in such a way as to have a relatively smaller angle with respect to the main pipe, and if the hydrogen injection hole corresponding to the injection pipe is located on the top of the main pipe, the corresponding injection pipe may be connected to the main pipe in such a way as to have a given angle close to a vertical angle with respect to the main pipe.

[0010] According to the embodiment of the present invention, to allow a blending ratio of natural gas to hydrogen to increase slowly, an amount of hydrogen injected from the front side hydrogen injection hole toward the rear side hydrogen injection hole may increase gradually.

[0011] According to the embodiment of the present invention, the facility may further include a gas analyzer for measuring the blending ratio of natural gas to hydrogen of the blended gas of the hydrogen and natural gas, so that if the blending ratio of the blended gas does not reach a set value, one of the plurality of hydrogen injection holes may be a supplement injection hole for additionally injecting hydrogen.

[0012] According to the embodiment of the present invention, the main pipe may include: at least one or more static mixers for converting the flow of the blended gas into vortexes to allow hydrogen and natural gas to be blended uniformly with each other; and at least one or more flow distributors for uniformly maintaining the flow in the main pipe.

[0013] According to the embodiment of the present invention, the at least one or more static mixers may be located on given areas of the main pipe behind given distances from the plurality of hydrogen injection holes so that the plurality of hydrogen injection holes and the at least one or more static mixers may be alternately located.

[0014] According to the embodiment of the present invention, the at least one or more flow distributors may be located behind given distances from the at least one or more static mixers and configured as a multi-port system to allow the blending ratio of natural gas to hydrogen to be kept consistently.

[0015] According to the present invention, the hydrogen blending facility for a natural gas pipeline can allow the blended gas to be fed safely and stably.

[0016] FIG. 1 is a side view showing a main pipe and a plurality of injection pipes of a hydrogen blending facility for a natural gas pipeline according to an embodiment of the present invention.

[0017] FIG. 2 is a side view showing a static mixer in the main pipe of the hydrogen blending facility according to the embodiment of the present invention.

[0018] FIG. 3 is a perspective view showing a flow distributor of the hydrogen blending facility according to the embodiment of the present invention.

[0019] FIG. 4 is a side view the hydrogen blending facility according to the embodiment of the present invention.

[0020] Hereinafter, an explanation of an embodiment of the present invention will be given in detail with reference to the attached drawings.

[0021] If it is determined that the detailed explanation on the well-known technology related to the present invention makes the scope of the present invention not clear, the explanation will be avoided for the brevity of the description.

[0022] In the description, the thicknesses of the lines or the sizes of the components shown in the drawing may be magnified for the clarity and convenience of the description. In the drawings, the corresponding parts in the embodiments of the present invention are indicated by corresponding reference numerals.

[0023] Objects, characteristics and advantages of the present invention will be more clearly understood from the detailed description as will be described below and the attached drawings. Before the present invention is disclosed and described, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to variously employ the present invention in virtually any appropriately detailed structure.

[0024] The term 'coupled' or 'connected', as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. To the contrarily, the term 'directly coupled' or 'directly connected', as used herein, is defined as connected without having any component disposed therebetween. In the description, when it is said that one portion is described as "includes" any component, one element further may include other components unless no specific description is suggested.

[0025] Now, an operating principle of the present invention will be described in detail with reference to the attached drawings. If it is determined that the detailed explanation on the well-known technology related to the present invention makes the scope of the present invention not clear, the explanation will be avoided for the brevity of the description. Further, the terms as will be discussed later are defined in accordance with the functions of the present invention, but may be varied under the intention or regulation of a user or operator. Therefore, they should be defined on the basis of the whole scope of the present invention.

[0026] FIG. 1 is a side view showing a main pipe and a plurality of injection pipes of a hydrogen blending facility for a natural gas pipeline according to an embodiment of the present invention.

[0027] Referring to FIG. 1, a main pipe 10 is a main path for transporting natural gas (NG), and a plurality of injection pipes 21, 22, 23, and 24 are connected to the main pipe 10. The injection pipes 21, 22, 23, and 24 serve to inject hydrogen into the main pipe 10, and the respective injection pipes are connected to the main pipe 10 through hydrogen injection holes formed on the main pipe 10.

[0028] According to the embodiment of the present invention, the hydrogen injection holes are spaced apart from one another at given intervals on the main pipe 10 in a moving direction of natural gas. That is, the injection pipes 21, 22, 23, and 24 are connected to the main pipe 10, while being spaced apart from one another at given intervals in the moving direction of natural gas, to allow hydrogen to be injected into the main pipe 10 sequentially. For example, the first injection pipe 21 is connected to the main pipe 10 at a first angle with respect to the main pipe 10, and the second injection pipe 22 is connected to the main pipe 10 at a second angle with respect to the main pipe 10, which is different from the first angle. The second angle is vertical to the main pipe 10, and the first angle is smaller than the second angle. In this case, an interval between the neighboring hydrogen injection holes is varied according to the number of hydrogen injection holes and a blending ratio of hydrogen. Further, each hydrogen injection hole has an independently operable injection valve. The injection valves serve to adjust amounts of hydrogen injected under the control of a central control system.

[0029] Injection of hydrogen into the main pipe 10 is step by step performed through the plurality of hydrogen injection holes. The hydrogen injection holes serve to inject uniform amounts of hydrogen sequentially into the main pipe 10 to blend natural gas and hydrogen little by little. To allow a blending ratio of natural gas to hydrogen to increase slowly, further, an amount of hydrogen injected from the front side hydrogen injection hole toward the rear side hydrogen injection hole increases gradually. As a result, the blending ratio of hydrogen in the main pipe 10 can increase slowly. Hydrogen has a faster diffusion speed and a lower density than natural gas, and therefore, if hydrogen is injected into the main pipe 10 at a single point of the main pipe 10, the blending ratio of hydrogen to natural gas becomes unbalanced. According to the embodiment of the present invention, the uniform blending of hydrogen and natural gas can be induced at an blending step. Under the above-mentioned configuration, that is, the blending ratio increases gradually to allow hydrogen and natural gas to be blended uniformly over the entire main pipe 10.

[0030] According to the embodiment of the present invention, the hydrogen injection holes are formed along the outer periphery of the main pipe 10 in different directions of the main pipe 10 in such a way as to have given angles with respect to the main pipe 10 to allow the hydrogen injected through the injection pipes 21, 22, 23, and 24 to be blended uniformly with the natural gas of the main pipe 10. In detail, the hydrogen injection holes are spaced apart from one another at given intervals on the main pipe 10 in the moving direction of natural gas, and in this case, the hydrogen injection holes are formed along the outer periphery of the main pipe 10 not in only one direction of the main pipe 10 but in different directions of the main pipe 10 in such a way as to have the given angles with respect to the main pipe 10. For example, if four injection pipes are located on the main pipe 10, the first injection pipe is connected to the top of the main pipe 10, the second injection pipe to the right side of the main pipe 10, the third injection pipe to the underside of the main pipe 10, and the fourth injection pipe to the left side of the main pipe 10. According to the embodiment of the present invention, hydrogen is injected not in any one direction of the main pipe 10 but in different directions of the main pipe 10, so that hydrogen and natural gas are blended naturally with each other.

[0031] According to the embodiment of the present invention, the respective injection pipes are connected to the main pipe 10 in such a way as to have the respective given angles with respect to the main pipe 10 to induce hydrogen and natural gas to be blended uniformly with each other. In detail, if the hydrogen injection hole is located on the underside of the main pipe 10, the corresponding injection pipe to the corresponding injection pipe is connected to the main pipe 10 in such a way as to have a relatively smaller angle with respect to the main pipe 10, and contrarily, if the hydrogen injection hole is located on the top of the main pipe 10, the corresponding injection pipe to the corresponding injection pipe is connected to the main pipe 10 in such a way as to have a given angle close to a vertical angle with respect to the main pipe 10. This is determined in consideration of the physical properties of natural gas and hydrogen. In detail, if hydrogen that is lighter than natural gas is injected into the hydrogen injection hole located on the top of the main pipe 10, the injected hydrogen is distributed in the upper portion of the interior of the main pipe 10, without being blended uniformly with the natural gas in the main pipe 10. Furthermore, hydrogen stays in the upper portion of the interior of the main pipe 10, without being blended with the natural gas, and is thus separated from the natural gas, so that it remains as a separate layer. To allow hydrogen to be injected into the main pipe 10 in a vertical direction to the flow of natural gas, therefore, the corresponding injection pipe is connected to the main pipe 10 in such a way as to have a given angle close to a vertical angle with respect to the main pipe 10. Contrarily, if hydrogen is injected into the hydrogen injection hole located on the underside of the main pipe 10, the hydrogen is distributed well in the main pipe 10, and therefore, the corresponding injection pipe is connected to the main pipe 10 in such a way as to have a small angle with respect to the main pipe 10. To allow hydrogen injected into the main pipe 10 to disperse well in consideration of such physical properties of natural gas and hydrogen, the injection pipe, which is connected to the hydrogen injection hole located on the underside of the main pipe 10, is connected to the main pipe 10 in such a way as to have a small angle with respect to the main pipe 10, and contrarily, the injection pipe, which is connected to the hydrogen injection hole located on the top of the main pipe 10, is connected to the main pipe 10 in such a way as to have a given angle close to a vertical angle with respect to the main pipe 10, which causes hydrogen to be injected into the main pipe 10 in a vertical direction to the flow of natural gas.

[0032] According to the embodiment of the present invention, the last hydrogen injection hole among the plurality of hydrogen injection holes serves as a supplement injection hole. In detail, a ratio of hydrogen to natural gas of blended gas of the hydrogen and natural gas is monitored in real time through a gas analyzer for measuring a blending ratio of hydrogen to natural gas of the blended gas, and if the blending ratio of hydrogen does not satisfy a set reference value, hydrogen is additionally injected through the last hydrogen injection hole so that the blending ratio of hydrogen reaches the set reference value. This enables a quality of blended gas to be kept consistently and allows the blending ratio to be kept at the set reference value.

[0033] According to the embodiment of the present invention, a lot of hydrogen is not injected at a time into the main pipe 10, and through the plurality of injection pipes 21, 22, 23, and 24, hydrogen is injected dividedly into the main pipe 10 so that hydrogen can be blended naturally with natural gas and the blending ratio can increase gradually.

[0034] According to the embodiment of the present invention, the main pipe 10 includes a static mixer for converting the flow of the blended gas into vortexes to allow hydrogen and natural gas to be blended uniformly with each other and a flow distributor for uniformly maintaining the flow in the main pipe 10. Explanations of the static mixer and the flow distributor will be given with reference to FIGs. 2 and 3.

[0035] FIG. 2 is a side view showing the static mixer in the main pipe of the hydrogen blending facility according to the embodiment of the present invention.

[0036] The static mixer is a convenient and economical blending device that does not consume any energy because it does not have any driving part and continuously and uniformly blends fluids in such a way as to allow the fluids to pass through a pipe through the mixing principles of division, conversion, and inversion. According to the embodiment of the present invention, the main pipe 10 has the static mixer disposed therein to allow hydrogen and natural gas to be blended uniformly with each other. According to the embodiment of the present invention, the static mixer is structured spirally and with multi-elements, and when the blended gas passes through the static mixer, a plurality of vortex flows are produced. Various types of static mixer may be provided. Examples of the static mixer include an inline static mixer 210, an uniflow static mixer 220, and an X-grid static mixer 230. However, they are just exemplary, and therefore, a variety of static mixers that are different in size and pattern may be provided to minimize the pressure loss of the blended gas and maximize the blending efficiency of the blended gas.

[0037] According to the embodiment of the present invention, the static mixer is located on a given area of the main pipe 10 behind a given distance from the hydrogen injection hole. If hydrogen is injected into the main pipe 10 through the hydrogen injection hole, the injected hydrogen and the natural gas are primarily blended through a dispersion process. To ensure a given area where the injected hydrogen is primarily blended naturally with natural gas in the main pipe 10, therefore, the static mixer is located on the given area of the main pipe 10 behind the given distance from the hydrogen injection hole. If initial blending of hydrogen and natural gas is completed through the natural blending area, hydrogen and natural gas are blended more uniformly with each other through the static mixer.

[0038] If the static mixer is located at a position very close to the hydrogen injection hole, hydrogen and natural gas are forcedly blended before the injected hydrogen sufficiently disperses, thereby causing a blending efficiency to become deteriorated. Further, turbulences or vortexes are generated from the flow of the blended gas just after the injection of hydrogen, thereby causing an unstable flow. If the static mixer is located in a state of such unstable flow, a degree of blending efficiency may decrease. Furthermore, big changes in pressure or temperature of blended gas may occur on an area just behind an area where hydrogen is injected, which has an influence on the durability of the static mixer. If the static mixer is located at a place where such changes are released, therefore, the lifespan of the static mixer extends and the maintenance thereof is easily performed.

[0039] The static mixer is located at an area where the flow of the blended gas is stabilized behind the given distance from the hydrogen injection hole, which achieves optimal blending performance.

[0040] According to the embodiment of the present invention, a distance between the hydrogen injection hole and the static mixer is set according to various operating conditions such as flow velocities, pressures, and temperatures of fluids. As a result, hydrogen and natural gas are naturally blended smoothly, and the blending efficiency of the static mixer is maximized.

[0041] Referring to FIG. 2, the static mixer is located at an area of 400 mm and has a distance of 1000 mm in front of it and a distance of 1000 mm behind it. Even if not shown in FIG. 2, the hydrogen injection holes are located at the distances of 1000 mm in front of the static mixer and behind the static mixer.

[0042] According to the embodiment of the present invention, if the plurality of hydrogen injection holes are provided, the hydrogen injection holes and the static mixers are alternately located. In this case, different types of static mixers may be alternately located. Further, the static mixer is located on a given area of the main pipe 10 behind a given distance from the hydrogen injection hole, and the next hydrogen injection hole is located behind a given distance from the static mixer. After the blended gas passes through the static mixer, natural gas and hydrogen are forcedly blended to increase a degree of blending uniformity. Just after the physical blending effectiveness of the static mixer has been completed, however, it is necessary to have time to allow the flows of the fluids to be stabilized again. If the hydrogen injection hole located behind the static mixer is very close to the static mixer, another hydrogen is injected in a state where the fluids are not stabilized, so that uniformity in the flows of fluids becomes deteriorated and the pressure in the flow of the blended gas in the pipe may be changed. Therefore, a given distance is ensured behind the area where the static mixer is located, thereby providing the area where the blended gas can be stabilized.

[0043] According to the embodiment of the present invention, uniform blending of hydrogen and natural gas can be performed efficiently.

[0044] FIG. 3 is a perspective view showing the flow distributor of the hydrogen blending facility according to the embodiment of the present invention.

[0045] The flow distributor is a device that uniformly keeps the flow in the main pipe 10. According to the embodiment of the present invention, the flow distributor designed to allow the blended gas to flow uniformly in the main pipe 10 is located inside the main pipe 10 to allow the blended gas of hydrogen and natural gas to be dispersed uniformly into the entire main pipe 10.

[0046] According to the embodiment of the present invention, the flow distributor is located behind a given distance from the static mixer. The blended gas is unstable in flow after passing through the static mixer, but the blended gas is stabilized naturally, while passing the given distance from the static mixer. As such a stabilization area is ensured, the flow distributor operates optimally. Further, the flow distributor is configured as a multi-port system to allow the blending ratio of natural gas to hydrogen to be kept consistently. The multi-port system is one of various types of flow distributors that disperses gas through multiple ports and uniformly keeps the flow in the pipe. As the respective ports distribute the same amount of gas therethrough, the efficiency of the system is improved. The multi-port system is effective in a large-scale pipe system and adjusts the flows of the respective ports individually in such a way as to appropriately satisfy various operating conditions.

[0047] According to the embodiment of the present invention, the flow distributor prevents the blended gas from flowing ununiformly, keeps the blending ratio consistently, allows the static mixer to perform optimal performance, and causes the blended gas in the pipe to flow uniformly, thereby maximizing the blending effectiveness.

[0048] FIG. 4 is a side view the hydrogen blending facility according to the embodiment of the present invention.

[0049] Referring to FIG. 4, a system is provided to efficiently blend hydrogen and natural gas in the main pipe and monitor and control a quality of blended gas and a flow rate thereof in real time. The hydrogen blending facility for a natural gas pipeline according to the present invention consists of a main pipe, a plurality of injection pipes, static mixers, a flow distributor, gas analyzers, and a central control system (not shown).

[0050] Natural gas is transported through the main pipe, and hydrogen is injected step by step through the plurality of injection pipes. The respective injection pipes are connected to the independent hydrogen injection holes on the main pipe, and hydrogen injection valves connected to the central control system are mounted on the hydrogen injection holes. The hydrogen injection valves adjust an amount of hydrogen injected according to blending ratio and flow rate of blended gas, thereby allowing a quality of blended gas to be kept consistently. The hydrogen injection holes are spaced apart from one another along the main pipe in a moving direction of natural gas, and distances of the hydrogen injection holes and amounts of hydrogen injected therethrough are determined according to the physical properties of hydrogen and natural gas.

[0051] The respective injection pipes are connected to the main pipe in such a way as to have given angles with respect to the main pipe. The positions and angles of the injection pipes are determined in consideration of the fact that hydrogen is lighter than natural gas and has a faster dispersion speed than natural gas. The hydrogen injection hole located on the underside of the main pipe is formed on the main pipe in such a way as to have a relatively small angle with respect to the main pipe, thereby accelerating the dispersion of hydrogen, and contrarily, the hydrogen injection hole located on the top of the main pipe is formed on the main pipe in such a way as to have a given angle close to a vertical angle with respect to the main pipe, thereby keeping blending uniformity. As a result, hydrogen and natural gas are blended naturally with each other, and the pressure and flow state of the blended gas in the main pipe are kept stably.

[0052] The blended gas whose initial blending is completed, after the injection of hydrogen, is physically blended more uniformly through the static mixers located inside the main pipe. The static mixer is located behind a given distance from the hydrogen injection hole, thereby ensuring an area where the injected hydrogen is primarily blended with natural gas naturally. Such a configuration optimizes the blending effectiveness of the static mixer and minimizes the pressure loss occurrable in the blending process.

[0053] The flow distributor is located behind the static mixer. The flow distributor serves to allow the blended gas to uniformly disperse in the entire pipe and effectively distribute the blended gas into the respective areas of the pipe through the multi-port system. In this case, the flow distributor is located behind a given distance from the static mixer. As a result, the flow distributor operates in a state where the flow of blended gas is stabilized, thereby improving the efficiency of the entire system.

[0054] The gas analyzers located inside the main pipe serve to monitor the blending ratio of the blended gas in real time, and the flow meters serve to monitor the flow rate of the blended gas. The monitored results are transmitted to the central control system, and if the blending ratio does not satisfy a reference value, hydrogen is additionally injected into the main pipe through the supplement injection hole, thereby adjusting the blending ratio. Such a function ensures a quality of blending gas and stably keeps a target blending ratio.

[0055] The central control system, which performs integral control for the entire facility, collects and analyzes data of flow rate, pressure, and blending ratio in the main pipe and controls the operations of the hydrogen injection valves, thereby allowing the blended gas to be transported stably and efficiently at constant pressure and flow rate.

[0056] According to the embodiment of the present invention, the hydrogen blending facility for a natural gas pipeline according to the present invention blends hydrogen and natural gas uniformly, transports them stably, and optimizes a quality of blended gas through real-time monitoring and control.

[0057] In the embodiment of the present invention, the components may be expressed in a singular or plural form. However, the singular or plural expressions may be appropriately chosen according to the suggested situations for the brevity of the description, and therefore, even the components expressed in the plural forms may be provided singularly, and vice versa.

[0058] The foregoing description of the embodiments of the invention has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Therefore, the present invention may be modified in various ways and may have several exemplary embodiments. Specific exemplary embodiments of the present invention are illustrated in the drawings and described in detail in the detailed description.　However, this does not limit the invention within specific embodiments and it should be understood that the invention covers all the modifications, equivalents, and replacements within the idea and technical scope of the invention.

Claims

1.A hydrogen blending facility for a natural gas pipeline, comprising:a main pipe for transporting natural gas; anda plurality of injection pipes connected to the main pipe to inject hydrogen into the main pipe,wherein the main pipe has a plurality of hydrogen injection holes formed thereon in such a way as to be connected correspondingly to the plurality of injection pipes, and the plurality of hydrogen injection holes are spaced apart from one another at given intervals on the main pipe in a moving direction of the natural gas, the plurality of injection pipes having a first injection pipe connected to a first hydrogen injection hole of the plurality of hydrogen injection holes in such a way as to have a first angle and a second injection pipe connected to a second hydrogen injection hole of the plurality of hydrogen injection holes in such a way as to have a second angle different from the first angle.2.The facility according to claim 1, wherein the plurality of hydrogen injection holes are formed along the outer periphery of the main pipe in different directions of the main pipe in such a way as to have given angles with respect to the main pipe.3.The facility according to claim 1, wherein if the hydrogen injection hole corresponding to the injection pipe is located on the underside of the main pipe, the corresponding injection pipe is connected to the main pipe in such a way as to have a relatively smaller angle with respect to the main pipe, and if the hydrogen injection hole corresponding to the injection pipe is located on the top of the main pipe, the corresponding injection pipe is connected to the main pipe in such a way as to have a given angle close to a vertical angle with respect to the main pipe.4.The facility according to claim 1, wherein to allow a blending ratio of natural gas to hydrogen to increase slowly, an amount of hydrogen injected from the front side hydrogen injection hole toward the rear side hydrogen injection hole increases gradually.5.The facility according to claim 1, further comprising a gas analyzer for measuring the blending ratio of natural gas to hydrogen of the blended gas of the hydrogen and natural gas, so that if the blending ratio of the blended gas does not reach a set value, one of the plurality of hydrogen injection holes is a supplement injection hole for additionally injecting hydrogen.6.The facility according to claim 1, wherein the main pipe comprises:at least one or more static mixers for converting the flow of the blended gas into vortexes to allow hydrogen and natural gas to be blended uniformly with each other; andat least one or more flow distributors for uniformly maintaining the flow in the main pipe.7.The facility according to claim 6, wherein the at least one or more static mixers are located on given areas of the main pipe behind given distances from the plurality of hydrogen injection holes so that the plurality of hydrogen injection holes and the at least one or more static mixers are alternately located.8.The facility according to claim 6, wherein the at least one or more flow distributors are located behind given distances from the at least one or more static mixers and configured as a multi-port system to allow the blending ratio of natural gas to hydrogen to be kept consistently.

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