A method of making a carbon electrode from agglomerated gas phase carbon

Abstract

This invention relates to a method for preparing carbon electrodes by condensing gaseous carbon, comprising the following steps: pyrolyzing a precursor gas containing gaseous carbon using plasma-enhanced chemical vapor deposition and condensing and sealing it into solid-phase carbon; mixing the solid-phase carbon, resin particles, and silver paste using a stirrer to obtain a mixture; hot-pressing the mixture into a carbon electrode using a hot-mounting machine; and testing the electrical properties of the carbon electrode. The advantages are: directly pyrolyzing and condensing gaseous carbon into solid-phase carbon for further preparation of carbon electrodes enables low-cost and rapid condensation and sealing of gaseous carbon.

Description

Technical Field

[0001] This invention relates to the field of carbon sequestration technology, specifically a method for preparing carbon electrodes by condensing gaseous carbon. Background Technology

[0002] Gaseous carbon is widely present in many fields, including the atmosphere, coalbed methane, oilfield gas, and refinery gas. Gaseous carbon sequestration is considered an important strategy to achieve a balance between energy resource utilization and greenhouse gas emission reduction. Currently, there are direct and indirect gaseous carbon sequestration schemes. Direct sequestration involves engineering measures to directly store gaseous carbon in underground gas storage facilities, geological layers, hydrates, or other suitable underground storage facilities. This requires geological exploration, engineering safety assessments, and environmental impact assessments, and typically takes several years to over a decade. Indirect carbon sequestration refers to utilizing gaseous carbon as a resource, converting it into other products or energy carriers for further use. Both direct and indirect conversion schemes exist. The direct method directly converts gaseous carbon into chemical products such as methanol, ethylene, or aromatics. This method is typically limited by reaction conditions, yield, and catalyst performance, and usually takes several hours to weeks. The indirect method first converts gaseous carbon into syngas, then uses the syngas as a raw material to produce downstream chemical products such as methanol, ammonia, dimethyl ether, low-carbon olefins, and liquid fuels. Synthetic ammonia, synthetic methanol, and synthetic liquid fuels are already industrialized. The indirect method typically involves specific and complex catalyst reactors, pyrolysis furnaces and cooling towers, product separation and purification equipment, taking several hours to days. The high time and equipment costs hinder the further development of gaseous carbon sequestration technology. Therefore, a new, low-cost, and rapid method for the sequestration and utilization of gaseous carbon is needed. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the above technical problems, this invention provides a method for preparing carbon electrodes by condensing gaseous carbon. The gaseous carbon is directly cracked and condensed into solid carbon, which is then further processed into carbon electrodes. This method enables low-cost and rapid storage and utilization of gaseous carbon.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing carbon electrodes by condensing gaseous carbon includes the following steps:

[0008] The precursor gas containing gaseous carbon was pyrolyzed and condensed into solid carbon using plasma-enhanced chemical vapor deposition (PECVD).

[0009] Solid carbon, resin particles, and silver paste are mixed using a mixer to obtain a mixture.

[0010] The mixture is hot-pressed into carbon electrodes using a hot-mounting machine;

[0011] Electrical performance testing of carbon electrodes.

[0012] Preferably, the PECVD method is a dual-RF inductively coupled jet plasma-enhanced chemical vapor deposition method; the precursor gas containing gaseous carbon is directly split into plasma by a plasma generator covered with dual RF inductively coupled coils, and the plasma torch is injected from the plasma generator into the reaction chamber, where it condenses and is sealed as solid carbon on the inner wall of the reaction chamber. The solid carbon is collected and subjected to X-ray diffraction analysis; the high-frequency inductively coupled coil power is 0.3-3kW and the frequency is 13.56MHz; the low-frequency inductively coupled coil power is 1-10kW and the frequency is 4MHz; the precursor gas containing gaseous carbon is methane and argon, with a methane flow rate of 0.01-1sccm and an argon flow rate of 0.1-5s lm; the back vacuum of the reaction chamber is 0.01-10Pa; the pressure of the reaction chamber during gaseous carbon condensation and sealing is 2000-10000Pa; and the condensation and sealing time is 0.5-1h.

[0013] Preferably, the mixture is prepared by mixing solid carbon, resin particles, and silver paste in a volume ratio of 1:0.1 to 100:0.1 to 10 in a mixer for 1 to 10 minutes.

[0014] Preferably, the hot mounting machine hot-presses the mixture into a tightly packed columnar solid carbon electrode. The hot pressing pressure of the hot mounting machine is 600-2000 Pa; the heating temperature is 50-100℃; the holding time is 3-15 min; and the cooling time is 3-15 min. The diameter of the carbon electrode is controlled by the inner mold of the mounting machine and can be set to 25 mm, 30 mm, 40 mm, or 50 mm.

[0015] Beneficial effects

[0016] This invention provides a method for preparing carbon electrodes by condensing gaseous carbon. It has the following beneficial effects:

[0017] This invention proposes a method for directly pyrolyzing and condensing gaseous carbon using PECVD. The precursor gas containing gaseous carbon is directly pyrolyzed into plasma using a dual-RF inductively coupled plasma-enhanced chemical vapor deposition device. The plasma is then condensed and sealed into solid carbon on the inner wall of the reaction chamber. A mixture is prepared using a stirrer and further hot-pressed into a carbon electrode using a hot-mounting machine. This method avoids the expensive time and chemical equipment costs and enables low-cost and rapid condensation and sealing of gaseous carbon. Attached Figure Description

[0018] Figure 1 A process flow diagram of the method for preparing carbon electrodes by condensing gaseous carbon provided by the present invention;

[0019] Figure 2 A schematic diagram of the dual radio frequency inductively coupled jet plasma enhanced chemical vapor deposition apparatus used for preparing carbon electrodes from condensed gaseous carbon provided by the present invention is shown below. 1 is a high-frequency inductively coupled coil, 2 is a plasma generator, 3 is a low-frequency inductively coupled coil, 4 is a reaction chamber, 5 is a vacuum pump group, 6 is the obtained solid carbon, and 7 is a plasma torch.

[0020] Figure 3 This is a schematic photograph of solid carbon prepared by condensing gaseous carbon according to Embodiment 1 of the present invention, shown as a black powder;

[0021] Figure 4 This is an X-ray diffraction diagram of solid carbon prepared by condensing gaseous carbon in Embodiment 1 of the present invention, showing amorphous carbon.

[0022] Figure 5 This is a schematic photograph of a carbon electrode prepared by condensing gaseous carbon according to Embodiment 1 of the present invention.

[0023] Figure 6 This is a schematic diagram of the electrical performance test results of the carbon electrode prepared by condensation of gaseous carbon in Embodiment 1 of the present invention. The cubic sheet resistance was measured and the average value was taken, showing that the sheet resistance of the carbon electrode is 8.517 kΩ / □.

[0024] Figure 7 This is a photographic schematic diagram of solid carbon prepared by condensing gaseous carbon in Example 2 of the present invention, showing black powder and clusters;

[0025] Figure 8 This is an X-ray diffraction diagram of solid carbon prepared by condensing gaseous carbon in Example 2 of the present invention, showing amorphous carbon.

[0026] Figure 9 This is a photographic schematic diagram of the carbon electrode prepared by condensing gaseous carbon according to Embodiment 2 of the present invention;

[0027] Figure 10 This is a schematic diagram of the electrical performance test results of the carbon electrode prepared by condensation of gaseous carbon in Embodiment 2 of the present invention. The cubic sheet resistance was measured and the average value was taken, showing that the sheet resistance of the carbon electrode is 17.17 kΩ / □. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] See Figure 1 and Figure 2 This invention provides a method for preparing a carbon electrode by condensing gaseous carbon, comprising the following steps: pyrolyzing a precursor gas containing gaseous carbon using plasma-enhanced chemical vapor deposition (PECVD) and condensing and sealing it into solid-phase carbon; mixing the solid-phase carbon, resin particles, and silver paste using a stirrer to obtain a mixture; hot-pressing the mixture into a carbon electrode using a hot-mounting machine; and testing the electrical properties of the carbon electrode. Specifically, the method involves: turning on the power supply of the dual-RF inductively coupled jet plasma-enhanced chemical vapor deposition device, turning on the power supply of the vacuum pump group, evacuating the reaction chamber to a back-bottom vacuum of 5 Pa, and introducing a precursor gas containing gaseous carbon, with a methane flow rate of 0.32 sccm and an argon flow rate of 1.68 s⁻¹. 1m; High-frequency and low-frequency inductively coupled coils are energized, with a high-frequency power of 0.5kW and a frequency of 13.56MHz, and a low-frequency power of 2kW and a frequency of 4MHz; The precursor gas containing gaseous carbon is cracked in the plasma generator to produce a plasma torch, which extends into the reaction chamber, condenses and seals as solid carbon on the inner wall of the reaction chamber, and is collected and analyzed by X-ray diffraction; The pressure of the reaction chamber during the condensation and sealing of gaseous carbon is 3000Pa; The condensation and sealing time is 0.5h; Solid carbon and resin particles are then... The silver paste was mixed in a mixer at a volume ratio of 1:1:0.1 for 3 minutes to obtain a mixture. The mixture was placed in the inner mold of a 25 mm diameter hot mounting machine, the mold cover was closed, and the mixture was hot-pressed into a tightly packed columnar solid carbon electrode at a hot pressing pressure of 800 Pa and a heating temperature of 80 °C for 5 minutes. After cooling for 5 minutes, the carbon electrode was removed and its electrical properties were tested using the four-probe method. The cubic sheet resistance was measured and the average value was taken, showing that the sheet resistance of the carbon electrode was 8.517 kΩ / □.

[0031] Example 2:

[0032] The difference between this embodiment and Embodiment 1 is as follows: the precursor gas containing gaseous carbon has a methane flow rate of 0.1 sccm and an argon flow rate of 1.0 s / m; the high-frequency power is 0.7 kW and the low-frequency power is 4 kW; the reaction chamber pressure during gaseous carbon encapsulation is 4000 Pa; the condensation and encapsulation time is 0.8 h; solid carbon, resin particles, and silver paste are mixed in a volume ratio of 1:2:0.1 in a mixer for 5 min; the hot pressing pressure of the hot mounting machine is 1000 Pa, the heating temperature is 100℃, and the temperature is maintained for 8 min. Specifically, the power supply to the dual-RF inductively coupled jet plasma-enhanced chemical vapor deposition device is turned on, the vacuum pump group is turned on, the back vacuum of the reaction chamber is evacuated to 5 Pa, and the precursor gas containing gaseous carbon is introduced, with a methane flow rate of 0.1 sccm and an argon flow rate of 1.0 s / m. lm; High-frequency inductively coupled coils and low-frequency inductively coupled coils are energized, with a high-frequency power of 0.7kW and a frequency of 13.56MHz, and a low-frequency power of 4kW and a frequency of 4MHz; The precursor gas containing gaseous carbon is cracked in the plasma generator to generate a plasma torch, which extends into the reaction chamber, condenses and seals as solid carbon on the inner wall of the reaction chamber, and is collected and subjected to X-ray diffraction analysis; The pressure of the reaction chamber during gaseous carbon condensation and sealing is 4000Pa; The condensation and sealing time is 0.8h; Solid carbon, resin particles, The silver paste was mixed in a mixer at a volume ratio of 1:2:0.1 for 5 minutes to obtain a mixture. The mixture was placed in the inner mold of a 25 mm diameter hot mounting machine, the mold cover was closed, and the mixture was hot-pressed into a tightly packed columnar solid carbon electrode at a hot pressing pressure of 1000 Pa and a heating temperature of 100 °C for 8 minutes. After cooling for 5 minutes, the carbon electrode was removed, and the electrical performance of the carbon electrode was tested using the four-probe method. The cubic sheet resistance was measured and the average value was taken, showing that the sheet resistance of the carbon electrode was 17.17 kΩ / □.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing carbon electrodes by condensing gaseous carbon, characterized in that, Includes the following steps: A precursor gas containing gaseous carbon was pyrolyzed and condensed into solid carbon using plasma-enhanced chemical vapor deposition (PECVD). The PECVD method was a dual-RF inductively coupled plasma (DICP) method. The precursor gas containing gaseous carbon was directly pyrolyzed into plasma by a plasma generator encased in a dual-RF inductively coupled coil. The plasma torch was injected from the plasma generator into the reaction chamber, where it condensed and was sealed into solid carbon on the inner wall of the chamber. The solid carbon was collected and subjected to X-ray diffraction analysis. The high-frequency DICP coil had a power of 0.3–3 kW and a frequency of 13.56 MHz; the low-frequency DICP coil had a power of 1–10 kW and a frequency of 4 MHz; the precursor gas containing gaseous carbon was methane and argon, with a methane flow rate of 0. The pressure of the reaction chamber is 0.01–1 sccm, the argon gas flow rate is 0.1–5 slm; the back vacuum of the reaction chamber is 0.01–10 Pa; the pressure of the reaction chamber during gaseous carbon condensation and sealing is 2000–10000 Pa; the condensation and sealing time is 0.5–1 h. A mixture is obtained by mixing solid carbon, resin particles, and silver paste in a mixer; the mixture is prepared by mixing solid carbon, resin particles, and silver paste in a volume ratio of 1:0.1-100:0.1-10 in a mixer for 1-10 minutes. The mixture is hot-pressed into carbon electrodes using a hot mounting machine; the hot mounting machine hot-presses the mixture into closely packed columnar solid carbon electrodes, the hot pressing pressure of the hot mounting machine is 600-2000 Pa; the heating temperature is 50-100℃; the holding time is 3-15 min; the cooling time is 3-15 min; the diameter of the carbon electrode is controlled by the inner mold of the mounting machine and is set to 25 mm, 30 mm, 40 mm, and 50 mm; Electrical performance testing of carbon electrodes.

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