Device for preparing high-purity carbon-containing gas for CVD (Chemical Vapor Deposition) cultivation diamond by using hair

Abstract

The utility model discloses a device for preparing high-purity carbon-containing gas for CVD (Chemical Vapor Deposition) cultivation of diamonds by using hair. The device consists of a hair carbonization and gasification unit and a gas purification unit, the hair carbonization and gasification unit comprises a tubular vacuum furnace, a vacuum pump, a feeding pipe and a coarse material pipe. The gas purification unit comprises a precision filter, a gas liquefier, a gas purifier, a storage tank, a circulating pump, a primary purification pipe, a secondary purification pipe, a discharge pipe and three recovery pipes. According to the utility model, the carbon-containing gas required for cultivating diamonds is prepared by using human hair or pet hair and the like, the equipment is simple, easy to implement and low in production cost, and the obtained carbon-containing gas (methane or carbon dioxide) is high in purity.

Description

TECHNICAL FIELD

[0001] The utility model relates to CVD (Chemical Vapor Deposition) diamond cultivation technical field, specifically relates to utilize hair preparation CVD cultivation diamond with high purity carbon-containing gas device. BACKGROUND

[0002] Chemical vapor deposition refers to the process of introducing gaseous or vaporized liquid reactants containing film-forming elements and other gases required for the reaction into a reaction chamber, and generating a thin film on the substrate surface through a chemical reaction. MPCVD (Microwave Plasma Chemical Vapor Deposition) technology is considered the most ideal method for preparing synthetic diamonds in the future because it can produce large-area, high-quality diamonds. It is also the most widely used method for preparing single-crystal diamonds at home and abroad. In the microwave plasma vapor deposition method, the microwave generator generates microwaves that are sent into the reactor, and the carbon-containing gas required for diamond cultivation is introduced into the reactor. Under the excitation of microwaves, glow discharge is generated in the reaction chamber, which ionizes the molecules of the reaction gas to produce plasma, thereby depositing diamond film on the substrate.

[0003] The carbon-containing gas required for traditional diamond cultivation using the microwave plasma vapor deposition method mainly includes methane (CH4) and carbon dioxide (CO2) and other gases. These gases are generally obtained in the form of industrial-grade high-purity gas through outsourcing, which is expensive. Keratin proteins are composed of amino acids, containing about 45% carbon, 28% oxygen, 15% nitrogen, 7% hydrogen, and 5% sulfur and other elements. They can be used to extract carbon-containing gas required for diamond cultivation. Currently, there are devices and methods for preparing diamonds using hair-extracted carbon sources, such as Chinese utility model patent applications with publication numbers CN 118183698 A and CN 117448794 A. These applications mainly include two parts: the extraction of carbon sources from hair and the preparation of diamonds using the extracted carbon sources. In the extraction of carbon sources from hair, existing methods generally use simple ultrasonic cleaning, crucible drying, and quartz tube heating and gasification to obtain the required carbon-containing gas. However, the purity of the obtained carbon-containing gas is relatively low, which not only increases the difficulty of diamond preparation but also affects the quality of the prepared diamonds. Therefore, further research is needed on the existing devices and methods for extracting carbon sources from hair. SUMMARY

[0004] The utility model solves the problem of low purity of carbon-containing gas extracted by the existing method and device for extracting carbon sources from hair, and provides a device for preparing high-purity carbon-containing gas for CVD diamond cultivation using hair.

[0005] To solve the above problems, the utility model is realized by the following technical solutions:

[0006] A device for producing high-purity carbon-containing gas for CVD-grown diamonds using hair comprises a hair carbonization and gasification unit and a gas purification unit. The hair carbonization and gasification unit includes a tubular vacuum furnace, a vacuum pump, a feed pipe, and a coarse material pipe. Both the feed pipe and the coarse material pipe are equipped with control valves. The inner liner of the tubular vacuum furnace is a heat-resistant quartz tube. The heat-resistant quartz tube is a hollow tube with an inlet and an outlet. Pretreated hair and catalyst are fed into the inlet of the feed pipe, and the outlet of the feed pipe is connected to the inlet of the heat-resistant quartz tube, while the outlet of the heat-resistant quartz tube is connected to the inlet of the coarse material pipe. The vacuum pump is connected to the inner cavity of the heat-resistant quartz tube in the tubular vacuum furnace. The gas purification unit includes a precision filter. The system includes a gas liquefier, a gas purifier, a storage tank, a circulating pump, a primary purification pipe, a secondary purification pipe, a discharge pipe, and three recovery pipes. Control valves are installed on the primary purification pipe, secondary purification pipe, discharge pipe, and three recovery pipes. The outlet of the coarse material pipe is connected to the inlet of the precision filter. The outlet of the precision filter is connected to the inlet of the gas liquefier via the primary purification pipe. The outlet of the gas liquefier is connected to the inlet of the gas purifier via the secondary purification pipe. The outlet of the gas purifier is connected to the inlet of the storage tank via the discharge pipe. The inlets of the three recovery pipes are respectively connected to the waste outlets of the precision filter, the gas liquefier, and the gas purifier. The outlets of the three recovery pipes are connected to the inlet of the feed pipe via the circulating pump.

[0007] In the above scheme, the gas liquefaction unit consists of a gas storage tank, a refrigeration outer layer, a temperature measuring thermocouple, a liquid nitrogen pipe, a cold water pipe, and a drain pipe. Control valves are installed on the liquid nitrogen pipe, cold water pipe, and drain pipe. The gas storage tank is a hollow tank with an inlet and an outlet. The inlet of the gas storage tank is the inlet of the gas liquefaction unit, and the outlet of the gas liquefaction unit is the outlet of the gas liquefaction unit. The refrigeration outer layer surrounds the outside of the gas storage tank, and its interior is filled with refrigerant. The temperature measuring thermocouple is located inside the refrigeration outer layer. A liquid nitrogen inlet and a cold water inlet are located on the top of the refrigeration outer layer, and a drain outlet is located on the bottom of the refrigeration outer layer. Liquid nitrogen is introduced into the inlet of the liquid nitrogen pipe, and its outlet is connected to the liquid nitrogen inlet of the refrigeration outer layer. Cold water is introduced into the inlet of the cold water pipe, and its outlet is connected to the cold water inlet of the refrigeration outer layer. The inlet of the drain pipe is connected to the drain outlet of the refrigeration outer layer, and its outlet discharges waste liquid.

[0008] In the above scheme, the catalyst fed into the inlet of the feed pipe is hydrogen, oxygen or metal oxide powder.

[0009] In the above scheme, heat-insulating plugs are installed at both the inlet and outlet of the heat-resistant quartz tube of the tubular vacuum furnace.

[0010] Compared with existing technologies, this invention effectively increases the yield and purity of carbon-containing gas by carbonizing, gasifying, filtering, liquefying, purifying, and recycling human or pet hair, thereby reducing the difficulty of diamond preparation and improving diamond quality. This invention features simple equipment, ease of implementation, low production cost, and high purity of the obtained carbon-containing gas (methane or carbon dioxide). Attached Figure Description

[0011] Figure 1 A schematic diagram of a high-purity carbon-containing gas apparatus for producing CVD-grown diamonds using hair.

[0012] The diagram is labeled as follows: 1-1, Tubular vacuum furnace; 1-2, Vacuum pump; 1-3, Feed pipe; 1-4, Coarse material pipe; 2-1, Precision filter; 2-2, Gas liquefaction unit; 2-2-1, Gas storage tank; 2-2-2, Freezing outer layer; 2-2-3, Temperature measuring thermocouple; 2-2-4, Liquid nitrogen pipe; 2-2-5, Cold water pipe; 2-2-6, Drain pipe; 2-3, Gas purifier; 2-4, Storage tank; 2-5, Circulation pump; 2-6, Primary purification pipe; 2-7, Secondary purification pipe; 2-8, Discharge pipe; 2-9, Recovery pipe. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with specific examples and the accompanying drawings. It should be noted that directional terms mentioned in the examples, such as "up," "down," "middle," "left," "right," "front," and "back," are only for reference to the directions in the accompanying drawings. Therefore, the directions used are for illustrative purposes only and are not intended to limit the scope of protection of this utility model.

[0014] See Figure 1 A device for preparing high-purity carbon-containing gas for CVD-grown diamonds using hair, comprising a hair carbonization and gasification unit and a gas purification unit.

[0015] The hair carbonization and gasification unit includes a tubular vacuum furnace 1-1, a vacuum pump 1-2, a feed pipe 1-3, and a coarse material pipe 1-4. Both the feed pipe 1-3 and the coarse material pipe 1-4 are equipped with control valves.

[0016] The tubular vacuum furnace 1-1 used in this invention is an existing tubular vacuum furnace 1-1, whose inner liner is a heat-resistant quartz tube. The heat-resistant quartz tube is a hollow tube with an inlet and an outlet. To prevent damage to the sealing rings at both ends of the heat-resistant quartz tube due to excessive temperature, heat-insulating plugs are installed at both the inlet and outlet of the heat-resistant quartz tube in the tubular vacuum furnace 1-1. The shape of the heat-insulating plug matches the inlet and outlet of the heat-resistant quartz tube, and it is cylindrical or cylindrical cup-shaped. The material is selected from high-temperature resistant, low expansion coefficient, and low thermal conductivity material, specifically quartz, alumina ceramic, and foamed ceramic material. Pre-treated hair and catalyst are fed into the inlet of the feed pipe 1-3, wherein the pre-treated hair is hair obtained after washing, degreasing, and drying, and the catalyst is hydrogen, oxygen, or metal oxide powder. The outlet of feed pipe 1-3 is connected to the inlet of heat-resistant quartz tube, and the outlet of heat-resistant quartz tube is connected to the inlet of coarse material pipe 1-4. Vacuum pump 1-2 is connected to the inner cavity of the heat-resistant quartz tube of tubular vacuum furnace 1-1.

[0017] The gas purification unit includes a precision filter 2-1, a gas liquefaction unit 2-2, a gas purifier 2-3, a storage tank 2-4, a circulation pump 2-5, a primary purification pipe 2-6, a secondary purification pipe 2-7, a discharge pipe 2-8, and three recovery pipes 2-9. Control valves are installed on the primary purification pipe 2-6, the secondary purification pipe 2-7, the discharge pipe 2-8, and the three recovery pipes 2-9.

[0018] The precision filter 2-1 uses an existing precision filter 2-1, and its purpose is to filter dust from the gas. The gas liquefaction device 2-2 can be an existing gas liquefaction device 2-2 or a specially designed gas liquefaction device 2-2, and its purpose is to liquefy the gas. The specially designed gas liquefaction device 2-2 of this utility model consists of a gas storage tank 2-2-1, a freezing outer layer 2-2-2, a temperature measuring thermocouple 2-2-3, a liquid nitrogen pipe 2-2-4, a cold water pipe 2-2-5, and a drain pipe 2-2-6. Control valves are installed on the liquid nitrogen pipe 2-2-4, the cold water pipe 2-2-5, and the drain pipe 2-2-6. The gas storage tank 2-2-1 is a hollow tank with an inlet and an outlet. The inlet of the gas storage tank 2-2-1 is the inlet of the gas liquefaction device 2-2, and the outlet of the gas liquefaction device 2-2 is the outlet of the gas liquefaction device 2-2. The outer cryogenic layer 2-2-2 surrounds the gas storage tank 2-2-1, and is filled with cryogenic fluid. A thermocouple 2-2-3 is located inside the outer cryogenic layer 2-2-2. A liquid nitrogen inlet and a cold water inlet are located at the top of the outer cryogenic layer 2-2-2, and a drain outlet is located at the bottom. Liquid nitrogen is introduced into the inlet of the liquid nitrogen pipe 2-2-4, and its outlet is connected to the liquid nitrogen inlet of the outer cryogenic layer 2-2-2. Cold water is introduced into the inlet of the cold water pipe 2-2-5, and its outlet is connected to the cold water inlet of the outer cryogenic layer 2-2-2. The inlet of the drain pipe 2-2-6 is connected to the drain outlet of the outer cryogenic layer 2-2-2, and its outlet discharges waste liquid. The gas purifier 2-3 uses an existing gas purifier 2-3, and its purpose is to purify specific gases, namely methane and / or carbon dioxide.

[0019] The outlet of the coarse feed pipe 1-4 is connected to the inlet of the precision filter 2-1. The outlet of the precision filter 2-1 is connected to the inlet of the gas liquefaction unit 2-2 via the primary purification pipe 2-6. The outlet of the gas liquefaction unit 2-2 is connected to the inlet of the gas purifier 2-3 via the secondary purification pipe 2-7. The outlet of the gas purifier 2-3 is connected to the inlet of the storage tank 2-4 via the discharge pipe 2-8. The inlets of the three recovery pipes 2-9 are connected to the waste outlets of the precision filter 2-1, the gas liquefaction unit 2-2, and the gas purifier 2-3, respectively. The outlets of the three recovery pipes 2-9 are connected to the inlet of the feed pipe 1-3 via the circulation pump 2-5 to improve the output rate and purity of the high-purity carbon-containing gas used for diamond cultivation.

[0020] The method for preparing CVD-grown diamonds using high-purity carbon-containing gas from hair, achieved using the above-mentioned apparatus, includes the following steps:

[0021] Step 1: Pre-treat the hair by washing, degreasing and drying it to obtain pre-treated hair, and then send the pre-treated hair into the inner cavity of the heat-resistant quartz tube of the tubular vacuum furnace 1-1.

[0022] Step 2: Start vacuum pump 1-2 to evacuate the inner cavity of the heat-resistant quartz tube. During this process, the tubular vacuum furnace 1-1 is first heated to 100-250 degrees Celsius and held for 1 hour to dehydrate and dry the hair. Then, the tubular vacuum furnace 1-1 is heated a second time to 300-400 degrees Celsius and held for 2 hours to cause high-temperature pyrolysis of the keratin protein in the hair, and the impurity gases generated by the high-temperature pyrolysis are removed using vacuum pump 1-2. Finally, the tubular vacuum furnace 1-1 is heated a third time to 500-800 degrees Celsius and held continuously to cause high-temperature carbonization of the hair, resulting in high-temperature carbonized hair.

[0023] Step 3: Heating the tubular vacuum furnace 1-1 for the fourth time, turning off the vacuum pump 1-2 to stop evacuating the inner cavity of the heat-resistant quartz tube, and sending the catalyst into the inner cavity of the heat-resistant quartz tube of the tubular vacuum furnace 1-1. The hair that has been carbonized at high temperature will be vaporized under the action of the catalyst to obtain carbon-containing gas.

[0024] The catalyst inside the heat-resistant quartz tube fed into the tubular vacuum furnace 1-1 is hydrogen, oxygen, or metal oxide powder. Different catalysts correspond to different gasification processes.

[0025] When hydrogen is used as the catalyst: The hair that has been carbonized at high temperature is heated to 800-1000 degrees in a vacuum environment in a tubular vacuum furnace 1-1. Then, the vacuum pump 1-2 is turned off to stop the vacuuming, and high-purity hydrogen H2 is introduced into the heat-resistant quartz tube of the tubular vacuum furnace 1-1. The carbonized hair at high temperature will react with hydrogen H2 to produce methane CH4 gas.

[0026] When oxygen is used as the catalyst: The hair that has been carbonized at high temperature is heated to 500-800 degrees in a vacuum environment in a tubular vacuum furnace 1-1. Then, the vacuum pump 1-2 is turned off to stop the vacuuming, and high-purity oxygen O2 is introduced into the heat-resistant quartz tube of the tubular vacuum furnace 1-1. The carbonized hair at high temperature will react with oxygen O2 to produce carbon dioxide CO2 gas for CVD grown diamonds.

[0027] When using metal oxide powder as the catalyst: Take out the hair that has been carbonized at high temperature and mix it evenly with high-purity metal oxide powder, such as copper oxide or iron oxide. This invention preferably uses high-purity copper oxide powder mixed evenly with the carbonized hair in a specific ratio, with a copper oxide to carbon weight ratio of at least 13.3. Place the evenly mixed copper oxide and carbon into the heat-resistant quartz tube of the tubular vacuum furnace 1-1, evacuate the furnace, and slowly raise the temperature to 400 degrees Celsius. Hold the temperature for 1-2 hours to fully remove the air adsorbed on the powder surface. Then, turn off the vacuum pump 1-2 to stop the vacuuming process. Continue to raise the temperature of the tubular vacuum furnace 1-1 to 500-800 degrees Celsius. At this high temperature, carbon and copper oxide undergo a reduction reaction to produce carbon dioxide (CO2) gas.

[0028] Step 4: Use precision filter 2-1 to filter the carbon-containing gas to remove dust and obtain the filtered carbon-containing gas.

[0029] Step 5: Use gas liquefaction device 2-2 to liquefy the filtered carbon-containing gas. Control the temperature of the refrigerant in gas liquefaction device 2-2 by controlling the ratio of liquid nitrogen and cold water entering gas liquefaction device 2-2, so as to cool and liquefy the filtered carbon-containing gas in the gas storage tank 2-2-1 of gas liquefaction device 2-2, and obtain liquefied carbon-containing gas.

[0030] Step 6: Use gas purifier 2-3 to purify the liquefied carbon-containing gas. The dedicated methane and / or carbon dioxide gas purifier 2-3 purifies the liquefied carbon-containing gas, removes trace impurities, and retains the methane and / or carbon dioxide gas to obtain methane and / or carbon dioxide gas for lab-grown diamonds.

[0031] Step 7: Store the methane and / or carbon dioxide gas used for growing diamonds in storage tanks 2-4.

[0032] Step 8: Periodically turn on the circulation pump 2-5 to send the impurities remaining in the precision filter 2-1, gas liquefaction unit 2-2 and gas purifier 2-3 into the inner cavity of the heat-resistant quartz tube of the tubular vacuum furnace 1-1 for further treatment.

[0033] By periodically circulating the impurities remaining in the precision filter 2-1, gas liquefaction unit 2-2, and gas purifier 2-3 into the tubular vacuum furnace 1-1 for further processing, the yield and purity of carbon-containing gas can be effectively increased, thereby reducing the difficulty of diamond preparation and improving the quality of diamonds.

[0034] It should be noted that although the embodiments described above are illustrative, they are not intended to limit the present invention. Therefore, the present invention is not limited to the specific embodiments described above. Any other embodiments obtained by those skilled in the art under the guidance of the present invention without departing from its principles are considered to be within the protection scope of the present invention.

Claims

1. A device for preparing CVD-grown diamonds using hair, characterized in that, It consists of a hair carbonization and gasification unit and a gas purification unit; The hair carbonization and gasification unit includes a tubular vacuum furnace (1-1), a vacuum pump (1-2), a feed pipe (1-3), and a coarse material pipe (1-4); both the feed pipe (1-3) and the coarse material pipe (1-4) are equipped with control valves; the inner liner of the tubular vacuum furnace (1-1) is a heat-resistant quartz tube; the heat-resistant quartz tube is a hollow tube with an inlet and an outlet; the inlet of the feed pipe (1-3) is used to feed pretreated hair and catalyst, the outlet of the feed pipe (1-3) is connected to the inlet of the heat-resistant quartz tube, and the outlet of the heat-resistant quartz tube is connected to the inlet of the coarse material pipe (1-4); the vacuum pump (1-2) is connected to the inner cavity of the heat-resistant quartz tube of the tubular vacuum furnace (1-1); The gas purification unit includes a precision filter (2-1), a gas liquefaction unit (2-2), a gas purifier (2-3), a storage tank (2-4), a circulation pump (2-5), a primary purification pipe (2-6), a secondary purification pipe (2-7), a discharge pipe (2-8), and three recovery pipes (2-9). Control valves are installed on the primary purification pipe (2-6), secondary purification pipe (2-7), discharge pipe (2-8), and the three recovery pipes (2-9). The outlet of the coarse material pipe (1-4) is connected to the inlet of the precision filter (2-1), and the outlet of the precision filter (2-1) is connected to the primary purification pipe. (2-6) is connected to the inlet of the gas liquefaction unit (2-2). The outlet of the gas liquefaction unit (2-2) is connected to the inlet of the gas purifier (2-3) through the secondary purification pipe (2-7). The outlet of the gas purifier (2-3) is connected to the inlet of the storage tank (2-4) through the discharge pipe (2-8). The inlets of the three recovery pipes (2-9) are connected to the waste outlets of the precision filter (2-1), the gas liquefaction unit (2-2), and the gas purifier (2-3), respectively. The outlets of the three recovery pipes (2-9) are connected to the inlet of the feed pipe (1-3) through the circulation pump (2-5).

2. The apparatus for preparing CVD-grown diamonds using hair according to claim 1, characterized in that, The gas liquefaction unit (2-2) consists of a gas storage tank (2-2-1), a refrigeration outer layer (2-2-2), a temperature measuring thermocouple (2-2-3), a liquid nitrogen pipe (2-2-4), a cold water pipe (2-2-5), and a drain pipe (2-2-6); control valves are installed on the liquid nitrogen pipe (2-2-4), the cold water pipe (2-2-5), and the drain pipe (2-2-6); the gas storage tank (2-2-1) is a hollow tank with an inlet and an outlet; the inlet of the gas storage tank (2-2-1) is the inlet of the gas liquefaction unit (2-2), and the outlet of the gas liquefaction unit (2-2) is the outlet of the gas liquefaction unit (2-2); the refrigeration outer layer (2-2-2) wraps around the outside of the gas storage tank (2-2-1), and the refrigeration outer layer (2-2-2)... The interior of the outer cryogenic layer (2-2-2) is filled with refrigerant; a thermocouple (2-2-3) is installed inside the outer cryogenic layer (2-2-2); a liquid nitrogen inlet and a cold water inlet are provided above the outer cryogenic layer (2-2-2), and a drain outlet is provided below the outer cryogenic layer (2-2-2); liquid nitrogen is introduced into the inlet of the liquid nitrogen pipe (2-2-4), and the outlet of the liquid nitrogen pipe (2-2-4) is connected to the liquid nitrogen inlet of the outer cryogenic layer (2-2-2); cold water is introduced into the inlet of the cold water pipe (2-2-5), and the outlet of the cold water pipe (2-2-5) is connected to the cold water inlet of the outer cryogenic layer (2-2-2); the inlet of the drain pipe (2-2-6) is connected to the drain outlet of the outer cryogenic layer (2-2-2), and the outlet of the drain pipe (2-2-6) discharges waste liquid.

3. The high-purity carbon-containing gas apparatus for preparing CVD-grown diamonds using hair according to claim 1, characterized in that, The catalyst fed into the inlet of the feed pipe (1-3) is hydrogen, oxygen or metal oxide powder.

4. The apparatus for preparing CVD-grown diamonds using hair according to claim 1, characterized in that, Insulating plugs are installed at both the inlet and outlet of the heat-resistant quartz tube of the tubular vacuum furnace (1-1).

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