A device for producing hydrogen carbon by cracking methane in molten metal, and a method for producing hydrogen carbon

Abstract

The application discloses a device and method for preparing hydrogen carbon by cracking methane in molten metal, wherein the device comprises a cracking reactor, the cracking reactor is filled with a molten metal catalyst, a gas inlet pipe is arranged on the cracking reactor, the gas inlet pipe is connected with a rotating driving mechanism outside, a gas injection blade is arranged on one end of the gas inlet pipe in the molten metal catalyst, a plurality of gas holes are arranged on the surface of the gas injection blade, a stator is arranged outside the gas injection blade, the stator is a hollow structure, and the peripheral wall of the stator is provided with an opening. When the hydrogen carbon is prepared, the rotating speed of the gas inlet pipe is set to 300-400 rad / s. In the application, the bubbles are discharged from the gas holes and then enter the stator, and then are dispersed again through the opening, so that the size of the cracking bubbles in the liquid medium is reduced, the contact efficiency with the molten metal catalyst is improved, the generation efficiency of the graphene is improved, and the conversion rate of the methane and the hydrogen selectivity are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of methane cracking and co-production of hydrogen and carbon, specifically to an apparatus for producing hydrogen and carbon from molten metal methane by cracking, and a method for preparing hydrogen and carbon using the apparatus. Background Technology

[0002] Natural gas cracking at high temperatures can simultaneously produce hydrogen and carbon materials. Without a catalyst, natural gas cracking requires high temperatures and consumes a lot of energy, and the produced carbon materials are mainly low-quality carbon black, resulting in low economic efficiency. Solid catalysts, such as platinum-palladium alloy catalysts, suffer from carbon deposition and deactivation, leading to significant catalyst waste. Using molten metal as a catalyst effectively avoids the problem of carbon materials depositing on the metal surface and occupying active sites, and its high catalytic activity allows for the preparation of high-quality graphene at lower temperatures.

[0003] However, in current methane cracking experimental devices using molten metal as a catalyst, the methane conversion rate is typically only 30-40%, resulting in low utilization of the feed gas, low purity of the produced hydrogen, and poor quality of the obtained graphene. The main reason for this phenomenon is the large size of the cracking bubbles in the liquid medium and their low contact efficiency with the molten metal catalyst.

[0004] Therefore, this patent application is filed. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus for producing hydrogen carbon from molten metal methane through cracking and a method for preparing hydrogen carbon, thereby solving the technical problem in the prior art where the cracking bubbles introduced into the molten catalyst are large in size and unevenly dispersed, resulting in low methane conversion rate and low graphene quality.

[0006] This invention is achieved through the following technical solution:

[0007] The first objective of this invention is to provide an apparatus for producing hydrogen and carbon from molten metal methane by cracking, comprising a cracking reactor filled with a molten metal catalyst, a gas inlet pipe on the cracking reactor, a rotary drive mechanism connected to the outside of the gas inlet pipe, an air jet blade connected to one end of the gas inlet pipe inside the molten metal catalyst, the surface of the air jet blade having a plurality of pores, a stator on the outside of the air jet blade, the stator having an internal hollow structure, and openings on the peripheral wall of the stator.

[0008] In an optional embodiment, the rotary drive mechanism is a rotary motor, which is fixedly connected to the end of the gas inlet pipe.

[0009] In an optional embodiment, a barrier sleeve is provided around the gas inlet pipe, the barrier sleeve and the gas inlet pipe are arranged at a distance, and the stator is connected to the end of the barrier sleeve.

[0010] In an optional embodiment, a connector is fixed to the end of the barrier cylinder, and the gas inlet pipe passes through the connector and is rotatably engaged with the connector.

[0011] In an optional embodiment, the barrier cylinder can withstand temperatures of 200–1400°C.

[0012] In an optional embodiment, the diameter of the jet blade is 3 / 5 to 4 / 5 of the stator diameter.

[0013] In an optional embodiment, a dispersing blade is fixedly provided on the gas inlet pipe, with both ends of the dispersing blade extending out from the barrier cylinder. The dispersing blade is located above the stator, and the barrier cylinder is provided with an annular hole for the dispersing blade to rotate.

[0014] In an optional embodiment, the diameter of the dispersing blades is 2 / 3 to 1 / 3 of the diameter of the pyrolysis reactor.

[0015] In an optional embodiment, a scraper is fixedly provided on the outside of the gas inlet pipe, with both ends of the scraper extending out from the barrier cylinder, and an annular through hole provided on the barrier cylinder for the scraper to rotate.

[0016] In an optional embodiment, the scraper consists of two blades forming a double-blade structure, with the bottoms of the two blades flush with the liquid surface of the molten metal catalyst.

[0017] In an optional embodiment, each of the blades is provided with a guide channel, and each guide channel is opened at an angle of 10° to 60° on each blade.

[0018] In an optional embodiment, the outer wall of the pyrolysis reactor is further provided with a reactor outlet, which is located at the end of the blade.

[0019] The second objective of this invention is to provide a method for preparing hydrogen carbon, which is carried out using an apparatus for producing hydrogen carbon by cracking molten metal methane as described in any of the preceding claims, wherein the rotational speed of the gas inlet pipe is set to 300-400 rad / s during operation.

[0020] The advantages and beneficial effects of this invention compared to the prior art are:

[0021] 1. The present invention provides an apparatus for producing hydrogen and carbon from molten metal methane by cracking. The feed gas is introduced through a gas inlet pipe. After the gas inlet pipe is introduced to the bottom of the cracking reactor, it enters the jet blades and forms bubbles. As the gas exits from the jet blades, it is cut through the gas holes and then enters the stator. When it exits from the openings, it is dispersed again, thereby reducing the size of the cracking bubbles in the liquid medium and improving the low contact efficiency with the molten metal catalyst.

[0022] 2. The method for producing hydrogen carbon from methane by cracking provided in this embodiment of the invention utilizes a hydrogen carbon production device, which increases the graphene generation efficiency, significantly improves the methane conversion rate, and also significantly improves the selectivity of hydrogen. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0024] Figure 1 This is a schematic diagram of a device for producing hydrogen carbon by cracking molten metal methane, provided in an embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the flow direction when bubbles enter and exit the jet blades in an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the stator structure provided in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the scraper structure provided in an embodiment of the present invention.

[0028] The markings and the components they represent in the attached diagram are as follows:

[0029] 1-Crack reactor, 2-Molten metal catalyst, 3-Gas inlet pipe, 4-Rotating motor, 5-Jet blade, 6-Barrier cylinder, 7-Connector, 8-Stator, 9-Opening, 10-Dispersion blade, 11-Scraper, 12-Guide channel, 13-Reactor outlet. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0031] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the invention.

[0032] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0034] Example 1:

[0035] like Figure 1As shown, an apparatus for producing hydrogen and carbon from molten metal methane through cracking includes a cracking reactor 1, which can be made of graphite, ceramic, or silicon carbide. A molten metal catalyst 2 is filled inside the cracking reactor 1. The molten metal catalyst 2 can be a single molten metal, a multi-component molten alloy, a single salt, a multi-component molten salt, or a mixture of salt and metal. A gas inlet pipe 3 is provided on the cracking reactor 1, and a rotary drive mechanism is connected to the outside of the gas inlet pipe 3. The gas inlet pipe 3 acts as a hollow rotating shaft and can rotate under the action of the rotary drive mechanism. The rotary drive mechanism can be a rotary motor 4, which is fixedly connected to the end of the gas inlet pipe 3. Adjusting the power of the rotary motor 4 changes the rotation speed of the gas inlet pipe 3. An air jet blade 5 is provided at one end of the gas inlet pipe 3 located inside the molten metal catalyst 2. The surface of the air jet blade 5 has multiple pores for dispersing the feed gas introduced from the gas inlet pipe 3 into the molten metal catalyst 2 through the pores. The pore diameter is 10–50 mm, and the material of the air jet blade 5 is limited to graphite or ceramic. Figure 2 As shown, the jet blade 5 is composed of a top plate and a bottom plate, which are connected to the top plate. The bottom plate is an arc-shaped plate that is concave upwards, forming a jet chamber between the top and bottom plates. Multiple air holes are provided on both the top and bottom plates. A stator 8 is located outside the jet blade 5. The stator 8 has a hollow internal structure and a square shape with an opening at the bottom. The jet blade 5 is located inside the stator 8. In this embodiment, the diameter of the jet blade 5 is set to 3 / 5 to 4 / 5 of the diameter of the stator 8 to ensure sufficient rotation of the jet blade 5 inside the stator 8 and to provide enough space to agitate the molten metal catalyst 2. Openings 9 are provided on the peripheral wall of the stator 8, such as... Figure 3 As shown, the aperture of the opening 9 is 1-10 mm, and the stator 8 is made of graphite or ceramic.

[0036] In this embodiment, the raw material gas is introduced through the gas inlet pipe 3, which leads to the bottom of the cracking reactor 1. The rotation of the gas inlet pipe 3 drives the jet blade 5 to rotate, and the gas enters the jet blade 5 to form bubbles. When the bubbles pass through the pores on the jet blade 5, they are dispersed and their size is reduced. The bubbles that come out of the pores on the jet blade 5 enter the stator 8. Some of them are cut multiple times in the local space of the stator 8 due to the agitation, and some float upward through the openings 9 on the stator 8. During the process of passing through the openings 9, the bubbles are dispersed a second time, thereby fully dispersing the bubbles and obtaining gas with small pore size and uniform dispersion. This reduces the size of the cracking bubbles in the liquid medium and improves the contact efficiency with the molten metal catalyst 2.

[0037] Furthermore, a barrier cylinder 6 is fitted around the gas inlet pipe 3, spaced apart from the gas inlet pipe 3, with the stator 8 connected to the lower end of the barrier cylinder 6. The barrier cylinder 6 can be made of graphite or ceramic, and can withstand temperatures from 200 to 1400℃. A connector 7 is fixed at the end of the barrier cylinder 6 away from the stator 8, and the gas inlet pipe 3 passes through the connector 7 and rotates with both the connector 7 and the stator 8. During operation, the barrier cylinder 6 is fixed and does not rotate. The barrier cylinder 6, located outside the gas inlet pipe 3, serves to reduce the rotational resistance of the gas inlet pipe 3 and provides heat insulation.

[0038] Example 2:

[0039] like Figure 1 The apparatus shown is a further improvement on Example 1 for the cracking of molten metal methane to produce hydrogen and carbon.

[0040] In this embodiment, a dispersing blade 10 is also fixedly provided on the gas inlet pipe 3. The two ends of the dispersing blade 10 extend out from the baffle cylinder 6. The dispersing blade 10 is located above the stator 8. The diameter of the dispersing blade 10 is 2 / 3 to 1 / 3 of the diameter of the pyrolysis reactor 1. The surface of the dispersing blade 10 is smooth and non-porous, and the material is limited to graphite or ceramic. The baffle cylinder 6 is provided with an annular hole for the dispersing blade 10 to rotate. The dispersing blade 10 is located on the upper part of the stator 8. The bubbles rising from the stator 8 are cut and dispersed again when passing through the dispersing blade 10.

[0041] Example 3:

[0042] An apparatus for producing hydrogen and carbon from molten metal methane by cracking is further improved based on Example 2. A scraper 11 is fixedly provided on the outside of the gas inlet pipe 3. Both ends of the scraper 11 extend out of the baffle cylinder 6, and the baffle cylinder 6 has an annular through hole for the scraper 11 to rotate.

[0043] Better yet, the scraper 11 consists of two blades, forming a double-blade structure. The length of the blades is the radius of the pyrolysis reactor 1, and the thickness is 1-10 cm. The material of the blades is limited to stainless steel, ceramic, or graphite. The bottoms of the two blades are flush with the liquid surface of the molten metal catalyst 2. Each blade is fixedly connected to the gas inlet pipe 3 and rotates with the rotation of the gas inlet pipe 3. A guide channel 12 is also formed on the surface of each blade, and each guide channel 12 is inclined on each blade at an angle of 10° to 60°.

[0044] A reactor outlet 13 is also provided on the outer wall of the pyrolysis reactor 1. The reactor outlet 13 is located at the end of the blade, and the end of the guide channel 12 extends to the inlet end of the reactor outlet 13.

[0045] During hydrocarbon generation, the carbon material that rises to the surface of the liquid tends to deposit, affecting the efficiency of carbon material generation. In this embodiment, a scraper 11 is provided. The rotation of the scraper 11 scrapes the rising carbon material out of the pyrolysis reactor 1. Driven by the airflow and in conjunction with the guiding channel 12, efficient removal of the carbon material is achieved.

[0046] In addition, in this embodiment, two support members are provided between the side of the barrier cylinder 6 and the inner wall of the cracking reactor 1. These can be designed as support rods (not shown in the figure). One support rod is provided on the barrier cylinder 6 between the dispersing blade 10 and the stator 8, and the other support rod is provided on the barrier cylinder 6 between the dispersing blade 10 and the scraper 11, thus providing support for the barrier cylinder 6. The working principle of the molten metal methane cracking to hydrogen-carbon apparatus of the present invention is as follows:

[0047] The raw gas enters below the surface of the molten medium through the gas inlet pipe 3. The rotating motor 4 drives the gas inlet pipe 3 to rotate, which in turn rotates the jetting blades 5. The gas is dispersed into the molten liquid through the jetting blades 5, forming bubbles. These bubbles, dispersed by the jetting blades 5, are further reduced in size by the openings 9 of the stator 8. As the smaller bubbles rise, they encounter the rotating dispersing blades 10, which further agitate and disperse them into even smaller bubbles, preventing aggregation during long-distance ascent. The smaller bubbles burst at the surface of the molten medium, generating and accumulating carbon material on the liquid surface. A rotating scraper continuously scrapes out the generated carbon material, which is then discharged from the reactor outlet 13 under the influence of the airflow. This device achieves efficient bubble dispersion in the liquid, enabling efficient preparation of carbon materials, thereby improving the conversion rate of methane and the quality of the obtained graphene product.

[0048] To further verify the effectiveness of this invention, the inventors filled a graphite crucible with a copper catalyst and heated it to a molten state at 1100°C using an electromagnetic induction coil. The molten metal had a viscosity of 0.003 Pa·s, a density of 8000 kg / m³, and a surface tension of 0.8 N / m. The flow rate of CH₄ gas was set to 4 L / min, and the gas inlet pipe 3 was introduced to the bottom of the graphite crucible reactor. Under gas pressure, the gas flow was dispersed into large bubbles through the pores on the jet blades 5. These large bubbles were then dispersed a second time into smaller bubbles through the openings 9 of the stator 8 under the stirring of the blades. The rotating dispersion blades 10 further broke up the rising bubbles, dispersing them a third time into even smaller bubbles. The bubbles burst at the liquid surface, generating carbon material. During the reaction, the rotating motor 4 drove the gas inlet pipe 3 to rotate at speeds set to 0 rad / s, 100 rad / s, 200 rad / s, 300 rad / s, and 400 rad / s. Methane is cracked into hydrogen and high-quality graphene under the action of a catalyst. The conversion rate of methane and the selectivity of hydrogen are obtained by online analysis by gas chromatography. The prepared graphene floats on the liquid surface and is collected by adsorption.

[0049] Table 1. Effect of dispersed gas at different rotation speeds on methane conversion rate.

[0050] Rotational speed / rad / s Bubble diameter / mm Methane conversion rate / % Hydrogen selectivity / % 0 21.334 40.2 88.6 100 11.872 51.5 92.4 200 9.532 69.3 95.3 300 3.911 85.2 99.5 400 4.132 82.1 99.0

[0051] As can be seen, the degree of gas dispersion and bubble breakage varies at different rotation speeds. Overall, the bubble size gradually decreases with increasing rotation speed. At 0 rad / s, the average bubble diameter is as high as 21.334 mm. As the rotation speed increases to 100 rad / s, the bubble diameter decreases significantly to 11.872 mm, and the methane conversion rate and hydrogen selectivity increase to 51.5% and 92.4%, respectively. When the rotation speed reaches 300 rad / s, the average bubble diameter decreases to 3.911 mm, and the methane conversion rate and hydrogen selectivity reach their highest levels of 85.2% and 99.5%, respectively. However, further increasing the rotation speed does not significantly change the average bubble diameter, and the methane conversion rate and hydrogen selectivity tend to stabilize, indicating that the gas is well dispersed at rotation speeds of 300 rad / s and 400 rad / s.

[0052] As can be seen, this device disperses the gas three times in the liquid medium by combining the rotor (gas inlet pipe 3) and the stator 8, significantly reducing the bubble size and achieving efficient bubble dispersion in the liquid, thus increasing the effective utilization rate of the liquid medium. On the other hand, the addition of a rotating scraper to the liquid surface increases the graphene generation efficiency. Through this synergistic effect, the conversion rate of methane is significantly improved to 85.2%, and the selectivity of hydrogen is as high as 99.5%.

[0053] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An apparatus for cracking molten metal methane to produce hydrogen and carbon, characterized in that, The device includes a pyrolysis reactor (1), which is filled with a molten metal catalyst (2). The pyrolysis reactor (1) is provided with a gas inlet pipe (3), which is connected to a rotary drive mechanism. One end of the gas inlet pipe (3) located inside the molten metal catalyst (2) is connected to a jet blade (5). The surface of the jet blade (5) is provided with multiple pores. The outside of the jet blade (5) is provided with a stator (8), which has an internal hollow structure. The peripheral wall of the stator (8) is provided with openings (9).

2. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 1, characterized in that, The rotary drive mechanism is a rotary motor (4), which is fixedly connected to the end of the gas inlet pipe (3).

3. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 1, characterized in that, A barrier cylinder (6) is sleeved on the outside of the gas inlet pipe (3), and the barrier cylinder (6) is arranged at a distance from the gas inlet pipe (3). The stator (8) is connected to the end of the barrier cylinder (6).

4. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 3, characterized in that, The end of the barrier cylinder (6) is fixed with a connector (7), and the gas inlet pipe (3) passes through the connector (7) and rotates with the connector (7).

5. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 3, characterized in that, The barrier cylinder (6) can withstand temperatures of 200 to 1400°C.

6. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 1, characterized in that, The diameter of the jet blade (5) is 3 / 5 to 4 / 5 of the diameter of the stator (8).

7. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 3, characterized in that, A dispersing blade (10) is fixedly provided on the gas inlet pipe (3). The two ends of the dispersing blade (10) protrude from the barrier cylinder (6). The dispersing blade (10) is located above the stator (8). The barrier cylinder (6) is provided with an annular hole for the dispersing blade (10) to rotate.

8. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 7, characterized in that, The diameter of the dispersing blade (10) is 2 / 3 to 1 / 3 of the diameter of the pyrolysis reactor (1).

9. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 3, characterized in that, A scraper (11) is fixedly provided on the outside of the gas inlet pipe (3). The two ends of the scraper (11) extend out from the barrier cylinder (6). An annular through hole is provided on the barrier cylinder (6) for the scraper (11) to rotate.

10. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 9, characterized in that, The scraper (11) consists of two blades forming a double-blade structure, with the bottom of the two blades flush with the liquid surface of the molten metal catalyst (2).

11. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 10, characterized in that, Each blade is provided with a guide channel (12), and each guide channel (12) is opened at an angle of 10° to 60° on each blade.

12. The apparatus for producing hydrogen and carbon from molten metal methane by cracking according to claim 10, characterized in that, The outer wall of the pyrolysis reactor (1) is also provided with a reactor outlet (13), which is located at the end of the blade.

13. A method for producing hydrogen carbon by cracking molten metal methane using the apparatus for producing hydrogen carbon by cracking according to any one of claims 1 to 12, characterized in that, During operation, the rotation speed of the gas inlet pipe (3) is set to 300-400 rad / s.

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