Natural gas hydrogen-doped mixer and mixing ratio adjusting method

Abstract

The invention relates to the technical field of gas mixing, and discloses a natural gas hydrogen-doped mixer which comprises an injector, a mixing pipeline and a rectifying piece, the injector comprises a central cavity and at least one annular cavity, the central cavity and the annular cavity are coaxially arranged, the annular cavity is located on the peripheral side of the central cavity, the central cavity is used for introducing natural gas, and the annular cavity is used for introducing hydrogen; in the flowing direction of the natural gas, the through-flow area of one side, close to the outlet, of the central cavity is gradually increased; the mixing pipeline is connected with the injector, and the rectifying part is arranged in the mixing pipeline. In the natural gas hydrogen-doped mixer, the hydrogen surrounds the natural gas jet flow, due to the fact that the speed difference exists between the natural gas and the hydrogen, the hydrogen sprayed at a high speed drives the natural gas flowing at a low speed after entering the mixing pipeline, the natural gas and the hydrogen are mixed in the shear layer, and the effect is good. The through-flow area of one side of the outlet of the central cavity is gradually increased, on one hand, the injection range of the natural gas is increased, the contact area of the natural gas and hydrogen is increased, and the mixing effect is better.

Description

Technical Field

[0001] The invention relates to the technical field of gas mixing, and in particular to a natural gas hydrogen blending mixer and a blending ratio adjustment method. Background Art

[0002] Mixing hydrogen into natural gas and transporting it through existing long-distance natural gas pipelines or urban gas pipelines, or supplying hydrogen through pipelines from nearby hydrogen sources, and finally using it at the end user is one of the current ways to use hydrogen energy on a large scale and at low cost. However, domestic research on natural gas hydrogen blending technology is still in its infancy. As the core of natural gas hydrogen blending technology, the structure of the blender greatly affects the development of natural gas hydrogen blending technology. The blenders in related technologies have problems such as large natural gas pressure loss, poor blending effect, and inconvenient adjustment of the blending ratio. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention provides a natural gas hydrogen blending mixer, which can adjust the blending ratio, has a good blending effect, and has a small natural gas pressure loss.

[0005] The natural gas hydrogen mixer of the embodiment of the present invention comprises an injector, a mixing pipeline and a rectifying component, wherein the injector comprises a central cavity and at least one annular cavity, wherein the central cavity is coaxially arranged with the annular cavity and the annular cavity is located on the outer peripheral side of the central cavity, the central cavity is used for introducing natural gas, the annular cavity is used for introducing hydrogen, and along the flow direction of the natural gas, the flow area of ​​the central cavity close to the outlet side gradually increases; the mixing pipeline is connected to the injector, and the natural gas and hydrogen sprayed by the injector are mixed in the mixing pipeline; the rectifying component is arranged inside the mixing pipeline, and the rectifying component can separate the mixed gas into multiple streams and change the flow direction of the mixed gas to achieve re-mixing of the mixed gas.

[0006] In the natural gas hydrogen blender of the embodiment of the present invention, natural gas is sprayed into the mixing pipeline from the central cavity of the injector, and hydrogen is sprayed into the mixing pipeline from the annular cavity. The hydrogen surrounds the natural gas jet. Due to the speed difference between the natural gas and the hydrogen, the high-speed injected hydrogen drives the low-speed flowing natural gas after entering the mixing pipeline, and the natural gas and hydrogen are mixed in the shear layer, with a better effect.

[0007] The flow area on the outlet side of the central cavity gradually increases, which, on the one hand, increases the injection range of natural gas, increases the contact area between natural gas and hydrogen, and improves the mixing effect. On the other hand, the increase in the flow area on the outlet side of the central cavity reduces the flow rate of natural gas, increases the speed difference between natural gas and hydrogen, and enables the high-speed injection of hydrogen to drive the low-speed flow of natural gas, thereby improving the mixing efficiency.

[0008] The rectifier plate can separate the mixed gas into multiple streams and change the flow direction to achieve re-mixing, thereby improving the mixing effect.

[0009] In some embodiments, the shape of the central cavity near the outlet is conical, and the taper angle of the cone is greater than zero and less than ninety degrees.

[0010] In some embodiments, there is only one annular cavity, and the annular cavity is sleeved on the outer circumference of the central cavity.

[0011] In some embodiments, the rectifying member includes a plurality of grid plates, each of the grid plates is provided with a plurality of flow channels, the plurality of flow channels can separate the mixed gas into a plurality of streams, and the plurality of grid plates are staggeredly arranged to change the flow direction of the mixed gas.

[0012] In some embodiments, the natural gas hydrogen mixer includes a filter unit, which is disposed between the outlet of the injector and the rectifying member, and is used to filter impurities in the mixed gas.

[0013] In some embodiments, the filter unit includes a filter and a drain pipe, the drain pipe is connected to the filter and is provided with a drain valve, and the drain pipe is used to discharge impurities in the filter.

[0014] In some embodiments, the natural gas hydrogen mixer includes a hydrogen inlet pipeline, the hydrogen inlet pipeline is in communication with the annular cavity, and the hydrogen inlet pipeline is provided with a valve, and the valve is used to adjust the flow rate of hydrogen in the hydrogen inlet pipeline.

[0015] In some embodiments, the natural gas hydrogen mixer includes a methane analyzer disposed downstream of the rectifying element, the valve element is a proportional valve, and the methane analyzer is used to detect the methane content in the mixed gas and can control the opening of the proportional valve.

[0016] In some embodiments, the injector, the blending pipeline and the natural gas pipeline are detachably connected, and / or the injector, the blending pipeline and the walls of the rectifier in contact with the gas are all provided with anti-hydrogen embrittlement coatings.

[0017] The embodiment of the present invention also provides a method for adjusting the blending ratio.

[0018] The blending ratio adjustment method of the embodiment of the present invention is based on the natural gas hydrogen blending mixer described in the above embodiment, and includes the following steps:

[0019] Step 1, detecting the content of methane in the mixing pipeline and calculating the hydrogen mixing ratio of the mixed gas;

[0020] Step 2: when the hydrogen blending ratio is higher than a set value, reducing the opening of the valve until the hydrogen blending ratio reaches the set value; when the hydrogen blending ratio is lower than the set value, increasing the opening of the valve until the hydrogen blending ratio reaches the set value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a natural gas hydrogen blending mixer according to an embodiment of the present invention.

[0022] Reference numerals:

[0023] 1. Injector; 11. Central cavity; 12. Annular cavity; 2. Mixing pipeline; 21. Methane analyzer; 3. Rectifier; 4. Filter unit; 41. Filter; 42. Drain pipeline; 421. Drain valve; 5. Hydrogen inlet pipeline; 51. Proportional valve; 6. Natural gas pipeline; 7. First set of flanges; 8. Second set of flanges; 9. Third set of flanges. DETAILED DESCRIPTION

[0024] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0025] like Figure 1 As shown, the natural gas hydrogen blending mixer of the embodiment of the present invention comprises an injector 1, a blending pipeline 2 and a rectifying member 3. The injector 1 comprises a central cavity 11 and at least one annular cavity 12, the central cavity 11 and the annular cavity 12 are coaxially arranged and the annular cavity 12 is located on the outer peripheral side of the central cavity 11, the central cavity 11 is used to pass natural gas, and the annular cavity 12 is used to pass hydrogen, and along the flow direction of the natural gas, the flow area of ​​the central cavity 11 close to the outlet side gradually increases; the blending pipeline 2 is connected to the injector 1, and the natural gas and hydrogen sprayed by the injector 1 are mixed in the blending pipeline 2; the rectifying member 3 is arranged inside the blending pipeline 2, and the rectifying member 3 can separate the mixed gas into multiple streams and change the flow direction of the mixed gas to achieve the re-blending of the mixed gas.

[0026] The injector 1 includes a central cavity 11 and at least one annular cavity 12, wherein the central cavity 11 and the annular cavity 12 are coaxially arranged and the annular cavity 12 is located on the outer periphery of the central cavity 11. It can be understood that: only one annular cavity 12 is provided and surrounds the outer periphery of the central cavity 11; or a plurality of annular cavities 12 are provided and the plurality of annular cavities 12 are arranged at intervals on the outer periphery of the central cavity 11.

[0027] The above arrangement allows hydrogen to surround the natural gas jet. Due to the speed difference between natural gas and hydrogen, the high-speed jetted hydrogen drives the low-speed flowing natural gas after entering the mixing chamber, and the natural gas and hydrogen are mixed in the shear layer, which has a better effect. Among them, the shear layer is located in the mixing pipeline, at the interface between natural gas and hydrogen, and the natural gas and hydrogen collide and mix at the shear layer.

[0028] Along the flow direction of natural gas, the flow area of ​​the central cavity 11 near the outlet gradually increases. It can be understood that the central cavity 11 near the outlet is in a gradually expanding shape. The above setting increases the contact area with hydrogen and improves the mixing effect; at the same time, the flow rate of natural gas is reduced, and the speed difference between natural gas and hydrogen increases, so that the high-speed injection of hydrogen drives the low-speed flow of natural gas, thereby improving the mixing efficiency.

[0029] The rectifying member 3 can separate the mixed gas into multiple streams and change the flow direction of the mixed gas. It can be understood that the rectifying member 3 can separate the gas and change the flow direction of the gas, and the separated gas will reunite after passing through the rectifying member 3. The above process realizes the re-mixing of hydrogen and natural gas, and improves the mixing effect.

[0030] Alternatively, if Figure 1 As shown, the shape of the central cavity 11 near the outlet is conical, and the taper angle value of the cone is greater than zero degree and less than ninety degrees.

[0031] For example, a cone has a taper angle value of 30 degrees.

[0032] The shape of the central cavity 11 near the outlet is set to be conical, which increases the injection range of the natural gas, increases the contact area with the hydrogen, and improves the mixing effect; at the same time, the flow rate of the natural gas is reduced, and the speed difference between the natural gas and the hydrogen is increased, so that the high-speed injection of hydrogen drives the low-speed flow of natural gas, thereby improving the mixing efficiency.

[0033] Alternatively, if Figure 1 As shown, only one annular cavity 12 is provided, and the annular cavity 12 is sleeved on the outer peripheral side of the central cavity 11 .

[0034] The injector 1 may be a sleeve structure formed by an outer tube and an inner tube. Specifically, the outer tube and the inner tube are connected by a connecting plate, an annular cavity 12 is formed between the outer tube and the inner tube, and a central cavity 11 is formed inside the inner tube.

[0035] The injector 1 has a relatively simple structure and is easy to process.

[0036] Optionally, the outer tube and the inner tube are detachably connected, and such an arrangement facilitates replacement of the inner tube with different taper angles according to different mixing conditions.

[0037] In some embodiments, Figure 1 As shown, the rectifying member 3 includes a plurality of grid plates, each grid is provided with a plurality of flow channels, the plurality of flow channels can separate the mixed gas into a plurality of streams, and the plurality of grids are staggeredly arranged to change the flow direction of the mixed gas.

[0038] For example, the grid plate can be clamped inside the mixing pipeline 2, and multiple grid plates are arranged along the direction of the mixed gas flow. The multiple grid plates are staggered so that the flow channels on different grid plates are staggered to achieve re-mixing of the mixed gas and improve the mixing effect.

[0039] Optionally, the grid plate and the mixing pipeline 2 are bonded.

[0040] In some embodiments, Figure 1 As shown, the natural gas hydrogen mixer comprises a filter unit 4, which is arranged between the outlet of the injector 1 and the rectifying member 3, and is used to filter impurities in the mixed gas.

[0041] Optionally, the filter unit 4 includes a filter 41 and a drain pipe 42 , the drain pipe 42 is connected to the filter 41 and a drain valve 421 is provided on the drain pipe 42 , and the drain pipe 42 is used to discharge impurities in the filter 41 .

[0042] For example, the filter 41 may be a filter screen that filters out impurities in the mixed gas by screening; or the filter 41 may be an adsorbent material that adsorbs impurities in the mixed gas by adsorption; or the filter 41 may be a combination of the above. When there are too many impurities in the filter 41 that cause blockage, the gas source of the injector 1 may be closed, and then the drain valve 421 may be opened, and the impurities may be discharged through the drain pipe 42.

[0043] There are some solid and liquid impurities in the natural gas and hydrogen transported through pipelines, such as tiny ceramic particles, sand, rust, oil, etc. These impurities may block the rectifier plate and even corrode the valve and instrument. Therefore, it is necessary to set the filter unit 4 to filter the impurities.

[0044] In some embodiments, Figure 1 As shown, the natural gas hydrogen mixer includes a hydrogen inlet pipeline 5 , which is communicated with the annular cavity 12 , and is provided with a valve member for adjusting the flow rate of hydrogen in the hydrogen inlet pipeline 5 .

[0045] Optionally, the natural gas hydrogen mixer includes a methane analyzer 21 disposed downstream of the rectifying element 3 , and the valve element is a proportional valve 51 . The methane analyzer 21 is used to detect the methane content in the mixed gas and can control the opening of the proportional valve 51 .

[0046] The methane content measured by the methane analyzer 21 can be used to calculate the hydrogen blending ratio of the mixed gas. When the hydrogen blending ratio is lower than the set value, the methane analyzer 21 controls the opening of the proportional valve 51 to increase until the hydrogen blending ratio reaches the set value; when the hydrogen blending ratio is higher than the set value, the methane analyzer 21 controls the opening of the proportional valve 51 to decrease until the hydrogen blending ratio reaches the set value.

[0047] By providing the methane analyzer 21 and the proportional valve 51 , the hydrogen blending ratio of the mixed gas can be automatically adjusted.

[0048] In some embodiments, Figure 1 As shown, the injector 1, the mixing pipeline 2 and the natural gas pipeline 6 are detachably connected.

[0049] Optionally, the inlet of the injector 1 is connected to the natural gas pipeline 6 via a first set of flanges 7, the outlet of the injector 1 is connected to the blending pipeline 2 via a second set of flanges 8, and the blending pipeline 2 is connected to the user-side natural gas pipeline via a third set of flanges 9. When a certain component needs to be replaced, the gas source of the injector 1 is turned off, and after the gas is exhausted, the corresponding flange buckle is disassembled to repair and replace the component.

[0050] The arrangement of the flange enables the natural gas hydrogen blending mixer of the embodiment of the present invention to be flexibly disassembled and replaced, is easy to maintain, and improves versatility.

[0051] In some embodiments, the walls of the injector 1, the mixing pipeline 2 and the rectifying member 3 that are in contact with the gas are all provided with a hydrogen embrittlement-resistant coating.

[0052] Optionally, the coating should be made of a material having the characteristics of high density, wear resistance, high economic benefits, etc., such as polyvinyl chloride (PVC), ethylene / vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), etc.

[0053] Optionally, the hydrogen inlet pipeline 5, the injector 1 and the mixing pipeline 2 are made of a material with excellent hydrogen embrittlement resistance, and the material may be austenitic stainless steel with a nickel content higher than 7%, such as stainless steel 304, stainless steel 316, etc.

[0054] In some embodiments, the size of the natural gas pipeline 6 is DN40, the size of the hydrogen inlet pipeline 5 is DN20, and the size of the blending pipeline 2 is DN45.

[0055] The following describes a method for adjusting the blending ratio according to an embodiment of the present invention.

[0056] The blending ratio adjustment method of the embodiment of the present invention is based on the natural gas hydrogen blending mixer in the above embodiment, and includes the following steps:

[0057] Step 1, detecting the content of methane in the mixing pipeline 2 and calculating the hydrogen mixing ratio of the mixed gas;

[0058] Step 2: when the hydrogen blending ratio is higher than the set value, reduce the opening of the valve until the hydrogen blending ratio reaches the set value; when the hydrogen blending ratio is lower than the set value, increase the opening of the valve until the hydrogen blending ratio reaches the set value.

[0059] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0060] In addition, the terms "first" and "second" are used for descriptive purposes only and should not 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.

[0061] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0063] 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.

[0064] 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 natural gas hydrogen blending mixer, characterized in that: include: An injector, wherein the injector comprises a central cavity and at least one annular cavity, wherein the central cavity is coaxially arranged with the annular cavity and the annular cavity is located on the outer peripheral side of the central cavity, the central cavity is used to introduce natural gas, and the annular cavity is used to introduce hydrogen, and along the flow direction of the natural gas, the flow area of ​​the central cavity close to the outlet side gradually increases; A mixing pipeline, the mixing pipeline is connected to the injector, and the natural gas and hydrogen sprayed by the injector are mixed in the mixing pipeline; A rectifying component is arranged inside the mixing pipeline, and the rectifying component can separate the mixed gas into multiple streams and change the flow direction of the mixed gas to achieve re-mixing of the mixed gas.

2. The natural gas hydrogen blending mixer according to claim 1, characterized in that: The shape of the central cavity near the outlet is conical, and the taper angle of the cone is greater than zero and less than ninety degrees.

3. The natural gas hydrogen blending mixer according to claim 2, characterized in that: There is only one annular cavity, and the annular cavity is sleeved on the outer peripheral side of the central cavity.

4. The natural gas hydrogen blending mixer according to claim 1, characterized in that: The rectifying member comprises a plurality of grid plates, each of the grid plates is provided with a plurality of flow channels, the plurality of flow channels can separate the mixed gas into a plurality of streams, and the plurality of grid plates are staggeredly arranged to change the flow direction of the mixed gas.

5. The natural gas hydrogen blending mixer according to claim 1, characterized in that: It comprises a filter unit, which is arranged between the outlet of the injector and the rectifying member, and is used for filtering impurities in the mixed gas.

6. The natural gas hydrogen blending mixer according to claim 5, characterized in that: The filter unit comprises a filter and a sewage pipeline, wherein the sewage pipeline is connected to the filter and a sewage valve is arranged on the sewage pipeline, and the sewage pipeline is used to discharge impurities in the filter.

7. The natural gas hydrogen blending mixer according to claim 1, characterized in that: It comprises a hydrogen inlet pipeline, which is communicated with the annular cavity and is provided with a valve component, and the valve component is used to adjust the flow rate of hydrogen in the hydrogen inlet pipeline.

8. The natural gas hydrogen blending mixer according to claim 7, characterized in that: It comprises a methane analyzer arranged downstream of the rectifying component, the valve component is a proportional valve, the methane analyzer is used to detect the methane content in the mixed gas and can control the opening of the proportional valve.

9. The natural gas hydrogen blending mixer according to any one of claims 1 to 8, characterized in that: The injector, the blending pipeline and the natural gas pipeline are detachably connected, and / or the injector, the blending pipeline and the wall surfaces of the rectifier that are in contact with the gas are all provided with a hydrogen embrittlement-proof coating.

10. A method for adjusting the blending ratio of the natural gas hydrogen blender according to claim 7 or 8, characterized in that: The following steps are involved: Step 1, detecting the content of methane in the mixing pipeline and calculating the hydrogen mixing ratio of the mixed gas; Step 2: when the hydrogen blending ratio is higher than a set value, reducing the opening of the valve until the hydrogen blending ratio reaches the set value; when the hydrogen blending ratio is lower than the set value, increasing the opening of the valve until the hydrogen blending ratio reaches the set value.

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