Gas mixing tank for realizing uniform mixing of hydrogen and natural gas and design method

Abstract

The invention discloses a gas mixing tank for realizing uniform mixing of hydrogen and natural gas and a design method, and relates to the technical field of natural gas hydrogen doping, the gas mixing tank comprises a tank body and at least two mixing units, all the mixing units are stacked in the tank body, and the gas passing directions of every two adjacent mixing units are different. According to the hydrogen and natural gas mixing device, the multiple mixing units are arranged in the tank body in the stacked mode, the gas passing directions of every two adjacent mixing units are different, when the gas passing directions are different, natural gas and hydrogen are promoted to be mixed in a crossed mode, uniform mixing of the hydrogen and the natural gas is achieved, and the flowing loss of the gas in the flowing process is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas hydrogen blending, and in particular to a gas mixing tank and a design method for achieving uniform mixing of hydrogen and natural gas. Background Art

[0002] The natural gas hydrogen mixing tank mixes natural gas and hydrogen in a certain proportion for users to use evenly. It can realize dynamic gas distribution and obtain a uniform mixed gas based on the volume ratio of hydrogen and natural gas. It is widely used in new energy vehicles, chemical industry, biomedicine, environmental protection and other fields.

[0003] Environmental pollution and energy shortage are two major problems that are becoming increasingly severe with the development of society. Hydrogen energy, as a clean, carbon-free, flexible, efficient and sustainable secondary energy source, can store energy, generate electricity and generate heat. It is an ideal energy carrier to help industries, transportation and other fields decarbonize deeply, and will play an important role in future energy supply. It takes a process to switch from traditional natural gas energy to clean, carbon-free hydrogen energy. "Natural gas fuel → natural gas blended with hydrogen fuel → hydrogen fuel" is the scientific and technological path to the zero-carbon goal. As an intermediate link, natural gas blended with hydrogen fuel plays an irreplaceable role in today's energy supply.

[0004] Natural gas-hydrogen-blended internal combustion engines are widely used in the fields of transportation and power generation to achieve energy conservation and emission reduction. Natural gas-hydrogen-blended fuel is a low-carbon gas fuel obtained by mixing hydrogen and natural gas in a certain volume ratio. It can make full use of hydrogen energy, solve the problems of wind and solar power abandonment, reduce carbon emissions, and has important social and economic benefits. Uniform natural gas-hydrogen-blended low-carbon fuel supply is crucial to the operation of the engine and is of great significance to improving combustion efficiency and power stability. At present, when mixing hydrogen and natural gas in the mixing tank, there is an uneven mixing problem. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies of the prior art and specifically provide a gas mixing tank and a design method for achieving uniform mixing of hydrogen and natural gas, as follows:

[0006] 1) In the first aspect, the present invention provides a gas mixing tank for achieving uniform mixing of hydrogen and natural gas, and the specific technical scheme is as follows:

[0007] It comprises a tank body and at least two blending units. All the blending units are stacked in the tank body, and the gas passing directions of every two adjacent blending units are different.

[0008] The beneficial effects of the gas mixing tank for uniformly mixing hydrogen and natural gas provided by the present invention are as follows:

[0009] A plurality of mixing units are stacked in the tank body, and the gas passing directions of each two adjacent mixing units are different. In different directions, the natural gas and hydrogen are encouraged to cross-mix with each other, so that the hydrogen and natural gas are evenly mixed and the flow loss of the gas during the flow process is reduced.

[0010] On the basis of the above scheme, the gas mixing tank for achieving uniform mixing of hydrogen and natural gas of the present invention can also be improved as follows.

[0011] Furthermore, when there is a first blending unit and a second blending unit, the air inlets of hydrogen and natural gas, the first blending unit, the second blending unit and the air outlet of the tank body are arranged in sequence, the air inlets of hydrogen and natural gas refer to: the air inlet of the hydrogen inlet pipeline and the air inlet of the natural gas inlet pipeline, and the air outlet of the tank body refers to: the air inlet of the mixed gas outlet pipeline located in the tank body.

[0012] Furthermore, the air inlet of the hydrogen intake pipeline is provided with a hydrogen convection porous injection device, on which a plurality of hydrogen injection holes are arranged, and the hydrogen convection porous injection device is arranged to offset the air inlet of the natural gas intake pipeline.

[0013] Furthermore, the size specifications of the tank body, the diameter of the hydrogen inlet pipeline and the diameter of the natural gas inlet pipeline are determined according to the demand for natural gas-hydrogen mixed gas, the hydrogen mixing volume ratio, the working pressure range, the working temperature range and the gas pipeline flow rate regulations.

[0014] Furthermore, the first mixing unit includes: at least one pair of cross-arranged first baffles, each of which is provided with a first flow direction hole, and the second mixing unit includes: at least one pair of cross-arranged second baffles, each of which is provided with a second flow direction hole, and the first mixing unit and the second mixing unit are staggered at 90°.

[0015] 2) In the second aspect, the present invention also provides a design method for a gas mixing tank for achieving uniform mixing of hydrogen and natural gas. The specific technical solution is as follows:

[0016] At least two mixing units are stacked in the tank body, and the gas passing directions of every two adjacent mixing units are different.

[0017] On the basis of the above scheme, the design method of a gas mixing tank for achieving uniform mixing of hydrogen and natural gas of the present invention can also be improved as follows.

[0018] Furthermore, when there is a first blending unit and a second blending unit, the air inlets of hydrogen and natural gas, the first blending unit, the second blending unit and the air outlet of the tank body are arranged in sequence, the air inlets of hydrogen and natural gas refer to: the air inlet of the hydrogen inlet pipeline and the air inlet of the natural gas inlet pipeline, and the air outlet of the tank body refers to: the air inlet of the mixed gas outlet pipeline located in the tank body.

[0019] Furthermore, the air inlet of the hydrogen intake pipeline is provided with a hydrogen convection porous injection device, on which a plurality of hydrogen injection holes are arranged, and the hydrogen convection porous injection device is arranged to offset the air inlet of the natural gas intake pipeline.

[0020] Furthermore, it also includes:

[0021] The size specifications of the tank, the diameter of the hydrogen inlet pipeline and the diameter of the natural gas inlet pipeline are determined based on the demand for natural gas-hydrogen mixed gas, the hydrogen blending volume ratio, the operating pressure range, the operating temperature range and the gas pipeline flow rate regulations.

[0022] Furthermore, the first mixing unit includes: at least one pair of cross-arranged first baffles, each of which is provided with a first flow direction hole, and the second mixing unit includes: at least one pair of cross-arranged second baffles, each of which is provided with a second flow direction hole, and the first mixing unit and the second mixing unit are staggered at 90°.

[0023] It should be noted that the beneficial effects achieved by the technical solution of the second aspect of the present invention and the corresponding possible implementation methods can be found in the above-mentioned technical effects of the first aspect and its corresponding possible implementation methods, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0025] Figure 1 This is a schematic structural diagram of a gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of a multi-hole injection method;

[0027] Figure 3 It is a structural schematic diagram of a hydrogen convection porous injection device;

[0028] Figure 4 is a schematic structural diagram of a first blending unit;

[0029] Figure 5 It is a schematic diagram of the structure of the second blending unit. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] like Figure 1 As shown, a gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to an embodiment of the present invention comprises a tank body 3 and at least two mixing units. All the mixing units are stacked in the tank body 3, and the gas passing directions of every two adjacent mixing units are different.

[0032] Optionally, in the above technical solution, when there is a first blending unit 1 and a second blending unit 2, the air inlets of hydrogen and natural gas, the first blending unit 1, the second blending unit 2 and the air outlet of the tank body 3 are arranged in sequence, the air inlets of hydrogen and natural gas refer to: the air inlet of the hydrogen inlet pipeline 9 and the air inlet of the natural gas inlet pipeline 10, and the air outlet of the tank body 3 refers to: the air inlet of the mixed gas outlet pipeline located in the tank body 3.

[0033] Optionally, in the above technical solution, a hydrogen convection porous injection device 11 is provided at the air inlet of the hydrogen inlet pipeline 9, and a plurality of hydrogen injection holes 12 are arranged on the hydrogen convection porous injection device 11, and the hydrogen convection porous injection device 11 is offset from the air inlet of the natural gas inlet pipeline 10, and the arrangement of the plurality of hydrogen injection holes 12 can be set according to actual conditions.

[0034] Optionally, in the above technical solution, the size specifications of the tank body 3, the diameter of the hydrogen inlet pipeline 9 and the diameter of the natural gas inlet pipeline 10 are determined according to the demand for natural gas-hydrogen mixed gas, the hydrogen blending volume ratio, the working pressure range, the working temperature range and the gas pipeline flow rate regulations.

[0035] Optionally, in the above technical solution, the first mixing unit 1 includes: at least one pair of cross-arranged first baffles 13, each first baffle 13 is provided with a first flow direction hole 14, the second mixing unit 2 includes: at least one pair of cross-arranged second baffles 15, each second baffle 15 is provided with a second flow direction hole 16, and the first mixing unit 1 and the second mixing unit 2 are arranged alternately with each other in a 90° rotation along the fluid flow direction.

[0036] The present invention is described by taking the configuration of two blending units as an example.

[0037] According to the demand for natural gas-hydrogen mixed gas, the volume ratio of hydrogen, the working pressure range, the working temperature range and the gas pipeline flow rate regulations, the size specifications of the tank body 3, the diameter of the hydrogen inlet pipeline 9, the diameter of the natural gas inlet pipeline 10 and the diameter of the mixed gas outlet pipeline are calculated. In this embodiment, the natural gas consumption of the internal combustion engine is 30kg / h, the pipeline gas transmission speed generally does not exceed 30m / s, the air flow speed in the mixing tank does not exceed 10m / s, the diameter of the static mixer is selected to be 400mm, the volume ratio of hydrogen is in the range of 0-20%, the diameter of the natural gas inlet pipeline 10 is selected to be 30mm, the diameter of the hydrogen inlet pipeline 9 is 20mm, and the diameter of the mixed gas outlet pipeline is 30mm.

[0038] The end of the natural gas intake pipeline 10 is in a diffused cone shape. According to the diameters of the natural gas and hydrogen pipes, a hydrogen convection porous injection device 11 is designed. The end of the hydrogen convection porous injection device 11 is in a conical diffusion shape, and a plurality of hydrogen injection holes 12 are provided at the end of the hydrogen convection porous injection device 11, which can increase the contact area between the natural gas and the hydrogen, and form convection with the inflowing natural gas, so as to achieve good pre-mixing. The other end of the hydrogen intake pipeline 9 enters the hydrogen storage bin. The upper end of the hydrogen storage bin is provided with an injection hole with a diameter of 6 mm, and hydrogen is input into the hydrogen intake pipeline 9, such as Figure 2 and Figure 3 shown.

[0039] After the natural gas and hydrogen are premixed, they enter the first blending unit 1 (the first blending unit 1 may also be denoted as SMX1). The structure of the first blending unit 1 is as follows: Figure 3 As shown, the first mixing unit 1 includes 4 rows of first baffles 13 (baffles can also be called cross plates), and the 4 rows of baffles form 2 groups of "X"-shaped cross structures, with an aspect ratio of l / D=0.75, and a thickness of the first baffle 13 of t=2mm. A plurality of first flow holes 14 are provided on each first baffle 13, and the plurality of first flow holes 14 are arranged in an array, and can also be arranged in other ways according to actual conditions. The diameter of the first flow hole 14 is 30mm. When the premixed natural gas and hydrogen pass through the first mixing unit 1, a portion of the gas is divided and changed in direction by the first baffle 13, and the other portion of the gas passes through the first flow hole 14 to form a jet, so that the two gases are fully merged after passing the first baffle 13, and are more fully mixed in both the flow direction and the radial direction, and the flow loss is small during the mixing process, as shown in FIG. Figure 4 shown.

[0040] The second mixing unit 2 (the first mixing unit 1 may also be denoted as SMX2) has the same structural specifications, i.e., geometric parameters, as the first mixing unit 1, and the arrangement and size of the first flow holes 14 and the second flow holes 16 may also be the same, such as Figure 5As shown. The second blending unit 2 is based on the first blending unit 1, rotated 90° along the fluid flow direction, and arranged in a staggered manner. This layout allows the premixed natural gas and hydrogen to rotate 90° when passing through the first blending unit 1 to flow to the second blending unit 2, under the action of the first baffle 13 and the second baffle 15, thereby increasing the rotational flow of the gas and greatly increasing the turbulence of the gas. It can promote the cross-mixing of the fluids in three dimensions: the flow direction, the radial direction of the mixing tank, and the flow rotation direction, thereby achieving uniform mixing of hydrogen and natural gas and reducing flow losses during the mixing process.

[0041] The working principle of the present invention is as follows: First, hydrogen is injected into natural gas through a plurality of hydrogen injection holes 12 arranged on a hydrogen convection multi-hole injection device 11, that is, hydrogen is injected into natural gas by multi-hole injection, so that hydrogen and natural gas form convection, and the premixing of the two gases is completed (also called preliminary blending). The premixed natural gas and hydrogen enter the first blending unit 1, and a plurality of first flow direction holes 14 are arranged on the first baffle plate 13 of the first blending unit 1. The first blending unit 1 includes multiple groups of "X"-shaped cross structures. When the premixed natural gas and hydrogen pass through the first baffle 13, part of the gas is divided and changed in direction by the first baffle 13, and the other part of the gas passes through the first flow hole 14 to form a jet, so that the two gases fully converge after passing through the first baffle 13, and are more fully mixed in the flow direction and radial direction. After passing through the first blending unit 1, it enters the second blending unit 2 which is staggered at 90 degrees with the first blending unit 1. The gas will increase the movement in the rotation direction, and promote the cross mixing of the gas in the three dimensions of flow direction, radial direction and rotation, so as to achieve uniform blending of hydrogen and natural gas, and obtain a uniformly mixed mixed gas (also called natural gas-hydrogen mixed gas) in a certain proportion, and reduce the flow loss in the mixing process. Improve the uniformity of the mixed gas of natural gas and hydrogen at different blending ratios, flow rates and intake pressures.

[0042] Optionally, the tank body 3 is further provided with components such as a bracket 8, a pressure gauge 5, a thermometer 6, a pressure relief valve 4, a sewage outlet 7 and an exhaust port. The bracket 8 is used to support the tank body 3 to facilitate the placement of the tank body 3. The pressure gauge 5 and the thermometer 6 are installed on the side of the tank body 3 to monitor the pressure P and temperature T of the mixing tank in real time during operation. The installation positions of the pressure gauge 5 and the thermometer 6 can be set according to actual conditions. A pressure relief valve 4 (also called a safety valve) is installed above the tank body 3. When the pressure in the tank body 3 exceeds the upper limit of the working pressure, the pressure relief valve 4 automatically opens to automatically discharge the internal gas, which is safe and reliable. The mixed gas (natural gas mixed with hydrogen) is discharged from the exhaust port for user use.

[0043] A method for designing a gas mixing tank for uniformly mixing hydrogen and natural gas according to an embodiment of the present invention includes:

[0044] At least two mixing units are stacked in the tank body 3, and the gas passing directions of every two adjacent mixing units are different.

[0045] Optionally, in the above technical solution, when there is a first blending unit 1 and a second blending unit 2, the air inlets of hydrogen and natural gas, the first blending unit 1, the second blending unit 2 and the air outlet of the tank body 3 are arranged in sequence, the air inlets of hydrogen and natural gas refer to: the air inlet of the hydrogen inlet pipeline 9 and the air inlet of the natural gas inlet pipeline 10, and the air outlet of the tank body 3 refers to: the air inlet of the mixed gas outlet pipeline located in the tank body 3.

[0046] Optionally, in the above technical solution, the air inlet of the hydrogen intake pipeline 9 is provided with a hydrogen convection porous injection device 11, on which a plurality of hydrogen injection holes 12 are arranged, and the hydrogen convection porous injection device 11 is offset from the air inlet of the natural gas intake pipeline 10.

[0047] Optionally, in the above technical solution, it also includes:

[0048] The size of the tank 3, the diameter of the hydrogen inlet pipeline 9 and the diameter of the natural gas inlet pipeline 10 are determined according to the demand for natural gas-hydrogen mixed gas, the hydrogen volume ratio, the operating pressure range, the operating temperature range and the gas pipeline flow rate regulations.

[0049] Optionally, in the above technical solution, the first mixing unit 1 includes: at least one pair of cross-arranged first baffles 13, each first baffle 13 is provided with a first flow direction hole 14, the second mixing unit 2 includes: at least one pair of cross-arranged second baffles 15, each second baffle 15 is provided with a second flow direction hole 16, and the first mixing unit 1 and the second mixing unit 2 are staggered at 90°.

[0050] In another embodiment, comprising:

[0051] S1. Determine the size of the tank 3, the diameter of the hydrogen inlet pipeline 9, and the diameter of the natural gas inlet pipeline 10 according to the demand for natural gas-hydrogen mixed gas, the hydrogen mixing volume ratio, the working pressure range, the working temperature range, and the gas pipeline flow rate regulations;

[0052] S2. According to the sizes of the gas mixing tank, natural gas pipeline and hydrogen pipeline in S1, hydrogen is injected into the gas mixing tank by multi-hole injection, and a hydrogen convection multi-hole injection device 11 is designed;

[0053] S3, designing a first blending unit 1 and a second blending unit 2;

[0054] S4. In the gas flow direction in the tank body 3 (the direction in which the natural gas and hydrogen entering the tank body 3 flow to the exhaust port of the tank body 3), the first blending unit 1 and the second blending unit 2 are arranged in a staggered 90° manner. This layout promotes the flowing gas to produce a rotational motion.

[0055] In S2, hydrogen is injected into natural gas through a plurality of hydrogen injection holes 12 arranged on the hydrogen convection multi-hole injection device 11, that is, hydrogen is injected into natural gas by multi-hole injection, so that hydrogen and natural gas form convection and complete premixing of the two gases.

[0056] In S3, when the premixed natural gas and hydrogen pass through the first blending unit 1, a part of the gas is divided and changed in direction by the first baffle 13, and the other part of the gas passes through the first flow hole 14 to form a jet, so that the two gases are fully merged after passing the first baffle 13, and the mixing is more complete in both the flow direction and the radial direction, and the flow loss during the mixing process is small.

[0057] In S4, the gas enters the second blending unit 2 which is staggered at 90 degrees with the first blending unit 1. The gas will increase the movement in the rotation direction, promote the cross-mixing of the gas in the three dimensions of flow direction, radial direction and rotation, increase the turbulence of the fluid, achieve uniform blending of hydrogen and natural gas, and reduce the flow loss during the mixing process.

[0058] It should be noted that the specific implementation process of the design method of a gas mixing tank for achieving uniform mixing of hydrogen and natural gas in an embodiment of the present invention is detailed in an embodiment of a gas mixing tank for achieving uniform mixing of hydrogen and natural gas, which will not be repeated here.

[0059] In the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0060] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0061] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A gas mixing tank for achieving uniform mixing of hydrogen and natural gas, characterized in that: It comprises a tank body and at least two blending units. All the blending units are stacked in the tank body, and the gas passing directions of every two adjacent blending units are different.

2. A gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to claim 1, characterized in that: When there is the first blending unit and the second blending unit, the air inlets of hydrogen and natural gas, the first blending unit, the second blending unit and the air outlet of the tank body are arranged in sequence, the air inlets of hydrogen and natural gas refer to: the air inlet of the hydrogen inlet pipeline and the air inlet of the natural gas inlet pipeline, and the air outlet of the tank body refers to: the air inlet of the mixed gas outlet pipeline located in the tank body.

3. A gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to claim 2, characterized in that: The air inlet of the hydrogen inlet pipeline is provided with a hydrogen convection porous injection device, on which a plurality of hydrogen injection holes are arranged, and the hydrogen convection porous injection device is arranged to offset the air inlet of the natural gas inlet pipeline.

4. A gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to claim 3, characterized in that: The size specifications of the tank body, the diameter of the hydrogen inlet pipeline and the diameter of the natural gas inlet pipeline are determined according to the demand for natural gas-hydrogen mixed fuel gas, the hydrogen mixing volume ratio, the operating pressure range, the operating temperature range and the gas pipeline flow rate regulations.

5. A gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to claim 4, characterized in that: The first mixing unit comprises: at least one pair of cross-arranged first baffles, each of which is provided with a first flow direction hole; the second mixing unit comprises: at least one pair of cross-arranged second baffles, each of which is provided with a second flow direction hole; the first mixing unit and the second mixing unit are staggered at 90°.

6. A method for designing a gas mixing tank for uniformly mixing hydrogen and natural gas, characterized in that: include: At least two mixing units are stacked in the tank body, and the gas passing directions of every two adjacent mixing units are different.

7. The method for designing a gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to claim 6, characterized in that: When there is the first blending unit and the second blending unit, the air inlets of hydrogen and natural gas, the first blending unit, the second blending unit and the air outlet of the tank body are arranged in sequence, the air inlets of hydrogen and natural gas refer to: the air inlet of the hydrogen inlet pipeline and the air inlet of the natural gas inlet pipeline, and the air outlet of the tank body refers to: the air inlet of the mixed gas outlet pipeline located in the tank body.

8. The method for designing a gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to claim 7, characterized in that: The air inlet of the hydrogen inlet pipeline is provided with a hydrogen convection porous injection device, on which a plurality of hydrogen injection holes are arranged, and the hydrogen convection porous injection device is arranged to offset the air inlet of the natural gas inlet pipeline.

9. The method for designing a gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to claim 8, characterized in that: Also includes: The size specifications of the tank body, the diameter of the hydrogen inlet pipeline and the diameter of the natural gas inlet pipeline are determined according to the demand for natural gas-hydrogen mixed fuel gas, the hydrogen mixing volume ratio, the operating pressure range, the operating temperature range and the gas pipeline flow rate regulations.

10. The method for designing a gas mixing tank for achieving uniform mixing of hydrogen and natural gas according to claim 9, characterized in that: The first mixing unit comprises: at least one pair of cross-arranged first baffles, each of which is provided with a first flow direction hole; the second mixing unit comprises: at least one pair of cross-arranged second baffles, each of which is provided with a second flow direction hole; the first mixing unit and the second mixing unit are staggered at 90°.

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