Method for mass production of spherical carbon by using metal ball to lift liquid metal catalyst to crack hydrocarbon gas

Abstract

The invention discloses a method for mass production of spherical carbon by cracking hydrocarbon gas with a metal ball lifting liquid metal catalyst. The method comprises the following steps: using a composite catalyst system formed by the metal ball and the liquid metal catalyst as a cracking reaction catalyst; the metal balls are selected from one or more of zirconium oxide balls, calcium oxide balls, nickel oxide balls, TZM alloy balls, tungsten carbide balls, titanium carbide balls and molybdenum carbide balls. The method has the advantages that the carbon curing rate of the liquid metal catalytic cracking hydrocarbon gas hydrogen production technology can be obviously improved, the efficient utilization of the feed gas is realized, and the production cost is further reduced.

Description

Technical Field

[0001] The invention relates to a carbon material production technology, in particular to a technology for producing carbon materials by catalytic cracking of carbon-containing gas by liquid metal. Background Art

[0002] The production and promotion of hydrogen energy is an important branch of green and low-carbon technology. The sustainable production of hydrogen has become an important issue to meet the future demand for hydrogen energy. The main part of the world's hydrogen production comes from steam methane reforming (SMR). In the long run, hydrocarbons will still be the main source of hydrogen. However, the SMR process is a high-energy consumption process and causes serious harm to the environment.

[0003] Liquid metal catalytic cracking of hydrocarbon gases is considered to be a promising green and low-carbon technology as a zero-emission, high-efficiency, low-cost hydrogen production and co-production of graphite carbon technology. It can be easily expanded to a large industrial scale and can obtain high value-added carbon materials.

[0004] Research has found that the technology of preparing hydrogen by catalytic cracking of hydrocarbon gas by liquid metal has problems such as low carbon solidification rate and easy formation of intermediate products, which makes it difficult for the raw hydrocarbon gas to be fully cracked into hydrogen and carbon materials, resulting in low yield of the process. Therefore, how to improve the carbon solidification rate of the process and thus reduce the production cost of producing hydrogen and graphite carbon materials using the process is a technical problem to be solved in this field. Summary of the invention

[0005] In order to improve the carbon solidification rate of liquid metal catalytic cracking of hydrocarbon gas to produce hydrogen technology, the present invention provides a method for using metal balls to enhance the mass production of spherical carbon by cracking hydrocarbon gas with liquid metal catalysts.

[0006] The technical solution adopted by the present invention is: a method for mass-producing spherical carbon by cracking hydrocarbon gas using a liquid metal catalyst using a metal ball, comprising the step of using a composite catalyst system formed by metal balls and a liquid metal catalyst as a cracking reaction catalyst.

[0007] As a further improvement of the present invention, the metal ball is selected from one or any of zirconium oxide balls, calcium oxide balls, nickel oxide balls, TZM alloy balls, tungsten carbide balls, titanium carbide balls, and molybdenum carbide balls. More preferably, the shape of the metal ball is spherical, teardrop-shaped or ellipsoidal, and the metal beads of the above shapes can form spherical carbon materials. More preferably, the particle size of the metal ball is 2 to 100 mm, and the metal beads of this particle size can make the composite catalyst system have a better efficiency in catalytic cracking of hydrocarbon gases, and the more preferred particle size range is 2 to 10 mm.

[0008] As a further improvement of the present invention, in the composite catalyst system, the metal spheres are located on the surface of the liquid metal catalyst or inside the liquid metal catalyst. When the metal spheres are located on the surface or inside the liquid metal catalyst, the composite catalyst system has good efficiency in catalytic cracking of hydrocarbon gases.

[0009] The composite catalyst system with metal spheres on the surface of the liquid metal catalyst can be formed in the following way: heat the corresponding metal material to the process-set temperature in a reaction vessel to form the liquid metal catalyst, and then add the metal spheres into the reaction vessel. The metal spheres naturally float on the liquid metal surface to form at least one layer of metal sphere layer, thus forming the composite catalyst system.

[0010] If it is desired to place the metal spheres inside the liquid metal catalyst, the following method can be adopted: heat the corresponding metal material to the process-set temperature in a reaction vessel to form the liquid metal catalyst, fix the metal spheres inside the liquid metal catalyst with a quartz mesh to form at least one layer of metal sphere layer, thus forming the composite catalyst system. In addition, the composite catalyst system can also be formed by adjusting the density of the metal spheres to make them float inside the liquid metal to form at least one layer of metal sphere layer. For example, when using metal spheres made of alloy materials, the density of the metal spheres can be adjusted by adjusting the proportions of various metals and compounds contained in the metal sphere material.

[0011] It should be noted that the metal sphere layer formed by the above method should not be too thick so as not to affect the catalytic efficiency, and it is preferably 1 to 3 layers.

[0012] Those skilled in the art can understand that the liquid metal catalyst used in the present invention is an alloy of one or any several of molten copper, tin, nickel, lanthanum, gallium, indium, bismuth, lead, silver, and zinc.

[0013] Those skilled in the art can understand that the method of the present invention further includes the step of introducing a hydrocarbon-containing raw material gas into the reaction vessel for cracking reaction to produce spherical carbon. The hydrocarbon-containing raw material gas is methane, propane, natural gas, flare gas or biogas; the temperature of the cracking reaction is 700 - 1600 °C.

[0014] The beneficial effects of the present invention are: improving the carbon solidification rate of the liquid metal catalytic cracking hydrocarbon gas to hydrogen production technology, realizing the efficient utilization of the raw material gas, and thus reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the method for the metal spheres to enhance the liquid metal catalyst to crack hydrocarbon gases to produce spherical carbon in Example 1.

[0016] Figure 2Schematic diagram of the method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by metal balls in Example 2. Detailed implementation mode

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0018] Example 1:

[0019] Catalytic cracking of carbon-containing gas to produce spherical carbon according to the following method:

[0020] (1) Put the copper-tin alloy into a quartz tube with air permeability at the bottom, introduce an inert gas at the bottom of the quartz tube, and heat to 1100 °C to form a liquid metal layer.

[0021] (2) Slowly pour spherical zirconia beads with a particle size of 8 mm into the quartz tube. The zirconia beads naturally float on the surface of the liquid metal. By controlling the addition amount of the zirconia beads, a two-layer zirconia bead layer is formed on the surface of the liquid metal to form a composite catalyst system.

[0022] (3) Close the inert gas and introduce methane gas with a flow rate of 0.5 L / min. Methane undergoes a cracking reaction under the catalysis of the composite catalyst, and finally spherical carbon is precipitated on the surface of the liquid metal. While the carbon material is precipitated, it is blown out and collected with an inert gas; the carbon solidification rate of methane is calculated by the amount of gas introduced and the amount of carbon collected.

[0023] Example 2:

[0024] Catalytic cracking of carbon-containing gas to produce spherical carbon according to the following method:

[0025] (1) Put the nickel-bismuth alloy into a quartz tube with air permeability at the bottom, introduce an inert gas at the bottom of the quartz tube, and heat to 1000 °C to form a liquid metal layer.

[0026] (2) For ellipsoidal titanium carbide balls with a particle size of 4 mm, adjust the density of the metal balls by adjusting the proportions of various metals and compounds contained in the metal ball material so that they float inside the liquid metal. The titanium carbide balls float inside the liquid metal catalyst to form a titanium carbide ball layer. By controlling the addition amount of the titanium carbide balls, a three-layer titanium carbide ball layer is formed inside the liquid metal to form a composite catalyst system.

[0027] (3) Close the inert gas and introduce propane gas with a flow rate of 1.3 L / min. Propane undergoes a cracking reaction under the catalysis of the composite catalyst, and finally spherical carbon is precipitated on the surface of the liquid metal. While the carbon material is precipitated, it is blown out and collected with an inert gas; the carbon solidification rate of propane is calculated by the amount of gas introduced and the amount of carbon collected.

[0028] Comparative Example 1:

[0029] This comparative example is a control experiment for Example 1, which is carried out under the same conditions and steps as Example 1, with the same dosages and batches of each raw material. The difference is that no zirconia beads are added. The specific steps are as follows:

[0030] (1) Put the copper-tin alloy into a quartz tube with air-permeable bottom, introduce an inert gas at the bottom of the quartz tube, and heat it to 1100 °C to form a liquid metal layer.

[0031] (2) Close the inert gas and introduce methane gas with a flow rate of 0.5 L / min. Methane undergoes a cracking reaction under catalysis, and finally spherical carbon is precipitated on the surface of the liquid metal. While the carbon material is being precipitated, it is blown out and collected with an inert gas; the carbon solidification rate of methane is calculated based on the amount of gas introduced and the amount of carbon collected.

[0032] Comparative Example 2:

[0033] This comparative example is a control experiment for Example 1, which is carried out under the same conditions and steps as Example 1, with the same dosages and batches of each raw material. The difference is that only zirconia beads are used as the catalyst. The specific steps are as follows:

[0034] (1) Place spherical zirconia balls with a diameter of 8 mm in the middle of the quartz tube, and fix them with quartz nets at both the upper and lower ends to form two layers of zirconia ball layers. Introduce an inert gas at the bottom of the quartz tube and heat it to 1100 °C.

[0035] (3) Introduce methane gas with a flow rate of 0.5 L / min. Methane undergoes a cracking reaction under the catalysis of zirconia beads, and spherical carbon is precipitated. While the carbon material is being precipitated, it is blown out and collected with an inert gas; the carbon solidification rate of methane is calculated based on the amount of gas introduced and the amount of carbon collected.

[0036] Comparative Example 3:

[0037] This comparative example is a control experiment for Example 1, which is carried out under the same conditions and steps as Example 1, with the same dosages and batches of each raw material. The difference is that the zirconia beads in Example 1 are replaced with quartz beads of the same particle size and shape. The specific implementation method is as follows:

[0038] (1) Put the copper-tin alloy into a quartz tube with air-permeable bottom, introduce an inert gas at the bottom of the quartz tube, and heat it to 1100 °C to form a liquid metal layer.

[0039] (2) Slowly pour spherical quartz beads with a diameter of 8 mm into the quartz tube. The quartz beads naturally float on the surface of the liquid metal, and by controlling the amount of quartz beads added, two layers of quartz bead layers are formed on the surface of the liquid metal to form a composite catalyst system.

[0040] (3) Turn off the inert gas and introduce methane gas at a flow rate of 0.5 L / min. Methane undergoes a cracking reaction catalyzed by the composite catalyst, and finally spherical carbon is deposited on the surface of the liquid metal. While the carbon material is deposited, it is blown out and collected with inert gas; the carbon solidification rate of methane is calculated based on the amount of gas introduced and the amount of carbon collected.

[0041] Detection of carbon solidification rate:

[0042] Detect the carbon solidification rate of each example and comparative example according to the following method:

[0043] (1) Inlet molar amount: Obtain the inlet mass in 30 min through a mass flowmeter, and calculate the inlet molar amount based on the ratio of the gas mass to the relative molecular mass of the gas;

[0044] (2) Molar amount of solid carbon: After introducing the gas for 30 min, separate the generated mixed carbon and weigh it with an analytical balance. Among them, the mixed carbon contains metal and carbon; measure the element content ratio of metal and carbon using inductively coupled plasma emission spectroscopy (ICP), and multiply the mass of the mixed carbon by the content of carbon element to obtain the mass of pure carbon; calculate the molar amount of solid carbon based on the ratio of the mass of pure carbon to the relative molecular mass of carbon;

[0045] (3) Carbon solidification rate: The percentage of the molar amount of solid carbon to the molar amount of the introduced gas.

[0046] (4) The detection results are shown in Table 1.

[0047] Table 1 Detection results of methane carbon solidification rate

[0048] Carbon curing rate % Example 1 58.2 Example 2 68.4 Comparative Example 1 38.7 Comparative Example 2 5.4 Comparative Example 3 39.8

[0049] As can be seen from Table 1, the method of using the metal balls of the present invention to enhance the production of spherical carbon by cracking hydrocarbon gases with liquid metal catalysts can increase the carbon solidification rate of the raw material gas to more than 65%.

[0050] From the comparison of Example 1, Comparative Example 1 and Comparative Example 2 in Table 1, it can be seen that when using liquid copper-tin alloy or zirconia beads alone as catalysts, the carbon solidification rates are 38.7% and 5.4% respectively. Theoretically, when the two are combined, the carbon solidification rate should be lower than 44.1%, while the actual measured value is 58.2%, which is significantly higher than the theoretical value of 32.0%. It can be seen that the components of the composite catalyst system of the present invention have a significant synergistic effect on increasing the carbon solidification rate.

Claims

1. Method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball, characterized in that: It includes the step of using a composite catalyst system formed by metal balls and a liquid metal catalyst as a catalyst for the cracking reaction.

2. The method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball according to claim 1, characterized in that: The metal balls are selected from one or any several of zirconia balls, calcium oxide balls, nickel oxide balls, TZM alloy balls, tungsten carbide balls, titanium carbide balls, and molybdenum carbide balls.

3. The method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball according to claim 2, characterized in that: The shape of the metal balls is spherical, water-drop-shaped or ellipsoidal.

4. The method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball according to claim 3, wherein: The particle size of the metal balls is 2 to 100 mm.

5. The method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball according to any one of claims 1 to 4, characterized in that: In the composite catalyst system, the metal balls are located on the surface or inside the liquid metal catalyst.

6. The method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball according to claim 5, characterized in that: The formation method of the composite catalyst system is as follows: in a reaction vessel, heat the corresponding metal material to the process-set temperature to form the liquid metal catalyst, and then add the metal balls to the reaction vessel. The metal balls naturally float on the surface of the liquid metal to form at least one layer of metal ball layer, thereby forming the composite catalyst system.

7. The method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball according to claim 5, characterized in that: The formation method of the composite catalyst system is as follows: in a reaction vessel, heat the corresponding metal material to the process-set temperature to form the liquid metal catalyst, and fix the metal balls inside the liquid metal catalyst with a quartz mesh to form at least one layer of metal ball layer, thereby forming the composite catalyst system.

8. The method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball according to claim 5, wherein: The formation method of the composite catalyst system is as follows: in a reaction vessel, heat the corresponding metal material to the process-set temperature to form the liquid metal catalyst, and adjust the density of the metal balls to make them float inside the liquid metal to form at least one layer of metal ball layer, thereby forming the composite catalyst system.

9. The method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball according to any one of claims 1 to 4, characterized in that: The liquid metal catalyst is an alloy of one or any several of molten copper, tin, nickel, lanthanum, gallium, indium, bismuth, lead, silver, and zinc.

10. The method for producing spherical carbon by cracking hydrocarbon gas with a liquid metal catalyst lifted by a metal ball according to any one of claims 6 to 8, characterized in that: It also includes the step of introducing a hydrocarbon raw material gas into the reaction vessel for a cracking reaction to produce spherical carbon; the hydrocarbon raw material gas is methane, propane, natural gas, flare gas or biogas; the temperature of the cracking reaction is 700 to 1600 °C.

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