A device for macro-continuous preparation of carbon nanospheres from coal-based oil and a preparation method thereof

Abstract

A kind of coal-based oil macro-quantitative continuous preparation nanometer carbon sphere device and preparation method, the output of carbon source preparation tank is connected with the burner one gas inlet on synthesis reactor by feed pump, combustible gas pipe is connected on the other gas inlet of burner, gas-solid separator is arranged on the top of synthesis reactor, carbon sphere conveyor is arranged on the bottom, the solid outlet of gas-solid separator is connected with carbon sphere conveyor, cooler is arranged on the outlet of carbon sphere conveyor;The present application uses coal-based oil as raw material, liquid carbon source is obtained by solvent allocation, compared with the method of using pure chemicals as carbon source in traditional way, raw material cost is greatly reduced. Nanometer carbon sphere is synthesized by lean-oxygen combustion method, by setting burner and porous baffle in synthesis reactor, one-step synthesis of carbon sphere is realized, synthesis steps are greatly simplified, synthesis efficiency is improved, and the demand of large-scale production is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nanocarbon sphere preparation, and particularly relates to a device and method for macro-continuous preparation of nanocarbon spheres from coal-based oil. BACKGROUND

[0002] Nanocarbon spheres are a new type of nanomaterial, which are carbon spheres with a size of less than 1000 nm, usually formed by carbon atoms through covalent bonds to form a spherical structure. Nanocarbon spheres have excellent properties such as high specific surface area, stable chemical properties, and good electrical conductivity, and are widely used in electrode materials for energy storage devices such as lithium ion batteries, catalysts or carriers, gas adsorption, storage and separation, pollutant adsorption in water treatment, and drug targeting delivery carriers. The main methods for preparing nanocarbon spheres are chemical vapor deposition, arc discharge, and hydrothermal method. The chemical vapor deposition and arc discharge methods have high requirements for equipment and are difficult to control, usually using low molecular hydrocarbons as carbon sources, resulting in high cost. Although the hydrothermal method is simple to operate, the obtained carbon spheres have high purity and good dispersion, and is widely used, but the carbon source required by the hydrothermal method is mostly pure chemicals, and the raw material cost is also high. Moreover, the hydrothermal method has a long processing time and many steps, and the intermittent operation also leads to low synthesis efficiency. For example, Chinese patent CN113582158A discloses a method for preparing carbon spheres in a polytetrafluoroethylene reaction kettle using p-phenylenediamine as a carbon source, which needs to be treated at 180℃ for 3 hours; Chinese patent CN116477605A discloses a method for preparing carbon spheres in a stirred tank using benzene diamine, hexamethylene tetramine, and polyoxyethylene polyoxypropylene ether block copolymer as carbon sources, which needs to be reacted for 24 hours; Chinese patent CN113648968A discloses a method for synthesizing carbon spheres using monosaccharide or disaccharide as a carbon source and alcohol as a control agent, which needs to be reacted at 130-170℃ for 3-12 hours; Chinese patent CN117023552A discloses a method for preparing carbon spheres using a high-pressure reaction kettle in an intermittent operation, which needs 6 steps to obtain carbon spheres. It can be seen that the current methods for preparing nanocarbon spheres have problems of high raw material cost and complex preparation steps, and most of them are carried out in a reaction kettle in an intermittent production mode, which leads to low product yield due to the inability to continuous production, which seriously limits the application process of nanocarbon spheres in emerging industrial fields. SUMMARY

[0003] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a device and method for macro-continuous preparation of nanocarbon spheres from coal-based oil, which has simple structure, can be operated continuously, has large production capacity, and is high in working efficiency.

[0004] The technical scheme adopted to solve the above technical problems is as follows: a device for preparing nanometer carbon balls in a macro-continuous mode from coal-based oil, an output port of a carbon source preparation tank is connected with a burner on a synthesis reactor through a feed pump and a combustible gas pipe connected with another gas inlet of the burner, a gas-solid separator is arranged at the top of the synthesis reactor, and a carbon ball conveyor is arranged at the bottom of the synthesis reactor, the solid outlet of the gas-solid separator is connected with the carbon ball conveyor, and a cooler is arranged at the outlet of the carbon ball conveyor.

[0005] The synthesis reactor is a shell with an inverted triangular longitudinal section, and a plurality of porous baffles are arranged in the shell along the gas path direction, the porous baffles are perpendicular to the two side plates of the shell and form an acute angle with the top plate of the shell, and the burner is vertically directed to the porous baffles.

[0006] Preferably, the inverted triangle is an inverted isosceles triangle, and the top angle α is 40°-50°.

[0007] Preferably, the number of the porous baffles is 6-8, and the angle between the porous baffles and the top plate of the shell is 55°-60°.

[0008] Preferably, the opening rate of the porous baffles is 75%-85%, and the pore diameter is 15-20 mm.

[0009] Preferably, the carbon ball conveyor is an electric spiral conveyor.

[0010] Preferably, the gas-solid separator is a cyclone separator.

[0011] The method for preparing nanometer carbon balls by the device comprises the following steps:

[0012] Step 1. Preheat the carbon source preparation tank to 40-60°C, and add coal-based oil and dilution solvent into the carbon source preparation tank in a mass ratio of 10:1-8:1 to mix uniformly to form a liquid carbon source.

[0013] Step 2. The feed pump pressurizes the prepared liquid carbon source to 0.2-0.4 MPa and sends it to the burner, the liquid carbon source is atomized by a combustible gas stream with a pressure of 0.25-0.45 MPa from the pipe network at the front end of the burner and undergoes a lean oxygen combustion reaction to form carbon nuclei, and the carbon nuclei gradually grow into carbon balls, the combustible gas stream is fuel gas in the starting stage, and is nitrogen-oxygen mixed gas after combustion, and the volume concentration of O2 in the nitrogen-oxygen mixed gas is 15%-18%.

[0014] Step 3. The flue gas carrying the carbon balls passes through the porous baffles in a cross flow, and most of the carbon balls fall into the bottom of the synthesis reactor and enter the carbon ball conveyor through step-by-step inertial interception, the flue gas carrying a small amount of carbon balls enters the gas-solid separator for re-separation, the separated carbon balls enter the carbon ball conveyor, the carbon ball conveyor conveys the carbon balls to the cooler, and the carbon balls are discharged after being cooled by the cooler to form the final carbon ball product.

[0015] Preferably, the coal-based oil is one or a mixture of two or more of medium-low temperature coal tar, high temperature coal tar, coal direct liquefaction oil, coal hot melt oil, coal solvent extraction oil, and coal oxidation liquid product.

[0016] Preferably, the dilution solvent is one or a mixture of two or more of n-pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, and gasoline fraction.

[0017] Preferably, the flow ratio of the combustible gas stream to the liquid carbon source in the burner is 14000:1 to 16000:1.

[0018] The beneficial effects of the present application are as follows:

[0019] The present application uses coal-based oil as raw material, and obtains liquid carbon source by solvent preparation. Compared with the traditional method of using pure chemicals as carbon source, the raw material cost is greatly reduced. The nano carbon spheres are synthesized by the lean oxygen combustion method, and by arranging the burner and the porous baffle inside the synthesis reactor, one-step synthesis of carbon spheres is realized, which greatly simplifies the synthesis steps, improves the synthesis efficiency, and meets the demand of large-scale production.

[0020] The nano carbon sphere preparation device of the present application has simple structure and can realize continuous operation, which improves the work efficiency and overcomes the problems of long time consumption and low yield caused by intermittent method in the existing kettle type synthesis process.

[0021] The present application reduces the generation of harmful by-products by the lean oxygen combustion method, is more friendly to the environment, and the prepared nano carbon spheres have high specific surface area, stable chemical properties, good electrical conductivity and other excellent properties, and can be widely used in lithium ion batteries, catalysts or carriers, gas adsorption storage and separation, water treatment, and drug targeting delivery carriers and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic diagram of the coal-based oil macro-continuous preparation of nano carbon sphere device of the present application.

[0023] Figure 2 is a longitudinal sectional view of the synthesis reactor 3.

[0024] Figure 3 is a carbon sphere composition and morphology characterization diagram.

[0025] Among them: carbon source preparation tank 1, feed pump 2, synthesis reactor 3, shell 3-1, porous baffle 3-2, gas-solid separator 4, condenser 5, carbon sphere conveyor 6, burner 7. DETAILED DESCRIPTION

[0026] The present application will be further described in detail below in combination with the drawings and examples, but the present application is not limited to the following embodiments.

[0027] Example 1

[0028] In Figure 1 、 2 the coal-based oil macro-continuous preparation of nanocarbon ball device of the embodiment, the output of the carbon source preparation tank 1 is connected with the gas inlet of the burner 7 through the feed pump 2, the burner 7 is installed on the front side plate of the synthesis reactor 3, the feed pump 2 transports the liquid carbon source in the carbon source preparation tank 1 to the burner 7, the other gas inlet of the burner 7 is connected with the combustible gas pipe, the combustible gas pipe inputs the combustible gas flow into the burner 7, the combustible gas flow is fuel gas in the starting stage, the fuel gas is one of natural gas, liquefied petroleum gas and coal gas, after burning, the combustible gas flow is switched to nitrogen-oxygen mixed gas. The gas-solid separator 4 is fixedly installed at the top of the rear side of the synthesis reactor 3, and the carbon ball conveyor 6 is fixedly installed at the bottom. The gas-solid separator 4 is a cyclone separator, which is used to separate the carbon balls in the flue gas, and the carbon balls are discharged to the carbon ball conveyor 6 through the solid discharge port 4-2 of the cyclone separator, and the flue gas is discharged through the gas discharge port 4-1 of the cyclone separator. The carbon ball conveyor 6 is an electric screw conveyor, and a cooler is installed on the outlet of the carbon ball conveyor 6, which is used to convey the generated carbon balls to the condenser 5 for cooling.

[0029] The synthesis reactor 3 of the embodiment includes a shell 3-1 and a plurality of porous baffles 3-2, and the shell 3-1 with a longitudinal section in the shape of an inverted isosceles triangle is provided with seven uniformly distributed porous baffles 3-2 along the gas path direction. The top angle α of the inverted isosceles triangle is 46°, the porous baffles 3-2 are seamlessly connected with the two side plates of the shell 3-1 and are perpendicular to the two side plates, are seamlessly connected with the top plate of the shell 3-1 and form an angle of 58° with the top plate, the opening rate of the porous baffles 3-2 is 80%, and the pore diameter is 18 mm. The porous baffles 3-2 are used to separate the carbon balls in the flue gas flow by impact in stages, and the burner 7 located at the front side is vertically directed to the porous baffles 3-2. The synthesis reactor 3 is designed to have a longitudinal section in the shape of an isosceles triangle, which is convenient for direct splicing and manufacturing of the reactor, simplifies the structure, reduces the manufacturing difficulty, is beneficial to the rapid falling of the carbon balls intercepted by the porous baffles 3-2 to the bottom of the synthesis reactor, maintains a certain material seal, and realizes the stable and continuous operation of the synthesis reaction device.

[0030] The method for preparing nanocarbon balls by the coal-based oil macro-continuous preparation nanocarbon ball device of the embodiment includes the following steps:

[0031] Step 1. Preheat carbon source preparation tank 1 to 50℃, add coal-based oil and dilution solvent into carbon source preparation tank 1 at a mass ratio of 9:1, mix uniformly to form liquid carbon source. The coal-based oil is one of medium-low temperature coal tar, high temperature coal tar, coal direct liquefaction oil, coal hot melt oil, coal solvent extraction oil, and oxidized liquid product of coal, or a mixture of two or more thereof. The dilution solvent is one of n-pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, and a mixture of two or more thereof.

[0032] Step 2. Feed pump 2 pressurizes the prepared liquid carbon source to 0.2-0.4 MPa and sends it to burner 7, where it is atomized by a combustible gas stream from the pipe network at a pressure of 0.25-0.45 MPa and undergoes lean oxygen combustion reaction to form carbon nuclei, which gradually grow into carbon spheres.

[0033] Step 3. The flue gas carrying the carbon spheres passes through the multi-hole baffle 3-2 in cross flow, and most of the carbon spheres fall into the bottom of the synthesis reactor 3 and enter the carbon sphere conveyor 6 through stepwise inertial interception. The flue gas carrying a small amount of carbon spheres enters the gas-solid separator 4 for further separation. The separated carbon spheres enter the carbon sphere conveyor 6, which transports the carbon spheres to the cooler, and the cooled carbon spheres are discharged to form the final carbon sphere product.

[0034] Example 2

[0035] In this embodiment, the synthesis reactor 3 includes a shell 3-1 and a multi-hole baffle 3-2. The shell 3-1 has a longitudinal cross-section in the shape of an inverted isosceles triangle. Six multi-hole baffles 3-2 are evenly distributed along the gas path direction inside the shell 3-1. The top angle α of the inverted isosceles triangle is 40°. The multi-hole baffles 3-2 are seamlessly connected to the two side plates of the shell 3-1 and are perpendicular to them. The multi-hole baffles 3-2 are seamlessly connected to the top plate of the shell 3-1 and form an angle of 55° with the top plate. The opening rate of the multi-hole baffles 3-2 is 75%, and the pore size is 15 mm. The multi-hole baffles 3-2 are used to separate the carbon spheres in the flue gas stream by impact. The burner 7 located on the front side is vertically directed towards the multi-hole baffles 3-2.

[0036] The other components and the connection relationship of the components are the same as in Example 1.

[0037] The method for preparing nanometer carbon spheres by the device for macro-continuous preparation of nanometer carbon spheres from coal-based oil in this embodiment is as follows:

[0038] Step 1. Preheat carbon source preparation tank 1 to 40℃, add coal-based oil and dilution solvent into carbon source preparation tank 1 at a mass ratio of 10:1, mix uniformly to form liquid carbon source.

[0039] Step 2. The feed pump 2 pressurizes the prepared liquid carbon source to 0.2-0.4 MPa and sends it to the burner 7, where it is atomized by a combustible gas stream from the pipe network with a pressure of 0.25-0.45 MPa and undergoes a lean oxygen combustion reaction to form carbon nuclei, which gradually grow into carbon spheres. The combustible gas stream is fuel gas during the start-up phase and nitrogen-oxygen mixed gas after combustion. The flow ratio of nitrogen-oxygen mixed gas to liquid carbon source is 14000:1, and the volume concentration of O2 in the nitrogen-oxygen mixed gas is 15%.

[0040] The other steps are the same as in Example 1.

[0041] Example 3

[0042] In this example, the synthesis reactor 3 includes a shell 3-1 and multiple porous baffles 3-2. Eight uniformly distributed porous baffles 3-2 are arranged in the shell 3-1 along the gas path direction, and the longitudinal section of the shell 3-1 is an inverted isosceles triangle with a top angle α of 50°. The porous baffles 3-2 are seamlessly connected to the two side plates of the shell 3-1 and are perpendicular to them, and are seamlessly connected to the top plate of the shell 3-1 at an angle of 60° with the top plate. The opening rate of the porous baffles 3-2 is 85%, and the pore size is 20 mm. The porous baffles 3-2 are used to separate the carbon spheres in the flue gas stream by impact separation. The burner 7 located on the front side is vertically directed towards the porous baffles 3-2.

[0043] The other components and the connection relationship of the components are the same as in Example 1.

[0044] The method for preparing nanocarbon spheres by the device for macro-continuous preparation of coal-based oil in this example is as follows:

[0045] Step 1. Preheat the carbon source preparation tank 1 to 60°C, and mix the coal-based oil and dilution solvent in the carbon source preparation tank 1 at a mass ratio of 8:1 to form a liquid carbon source.

[0046] Step 2. The feed pump 2 pressurizes the prepared liquid carbon source to 0.2-0.4 MPa and sends it to the burner 7, where it is atomized by a combustible gas stream from the pipe network with a pressure of 0.25-0.45 MPa and undergoes a lean oxygen combustion reaction to form carbon nuclei, which gradually grow into carbon spheres. The combustible gas stream is fuel gas during the start-up phase and nitrogen-oxygen mixed gas after combustion. The flow ratio of nitrogen-oxygen mixed gas to liquid carbon source is 16000:1, and the volume concentration of O2 in the nitrogen-oxygen mixed gas is 18%.

[0047] The other steps are the same as in Example 1.

[0048] Experiment

[0049] To verify the beneficial effects of the present application, the following experiments were conducted using the method for preparing nanocarbon spheres in Example 1.

[0050] The coal tar obtained by pyrolysis of Shenfu coal was used as carbon source to prepare carbon nanospheres in the laboratory. The carbon nanospheres were prepared according to the method of Example 1, and the carbon nanospheres were characterized in detail, and the results are shown in Figure 3 Figure 3 (a) The scanning electron microscope results show that the carbon nanospheres are uniform, and the size of a single particle is about 80-100 nm. As shown in Figure 3 (b), the absorption of the carbon nanospheres at a wave number of 3488 cm -1 represents the presence of some hydroxyl structures; and the peaks at 2819 cm -1 and 2734 cm -1 represent alkyl side chains. Since the two peaks are weak, it indicates that the number of alkyl side chains is small; the peaks at 1656 cm -1 , 1610 cm -1 , 859 cm -1 , 780 cm -1 , and 684 cm -1 are all absorption of aromatic rings. Since these peaks are strong, it indicates that the carbon nanospheres have high aromaticity; the peaks at 1388 cm -1 and 1355 cm -1 represent the absorption vibration of the methyl groups outside the aromatic ring and the ketone groups, respectively, indicating that there are a small amount of active functional groups such as methyl groups and ketone groups outside the aromatic core of the carbon nanospheres.

[0051] The above infrared analysis results show that the carbon nanospheres prepared by the present application have high aromaticity, and there are many active functional groups outside the aromatic ring. Therefore, the carbon nanospheres have many active sites, and are particularly suitable as electrode materials, catalysts or carriers, and gas adsorption, storage and separation materials, etc.

[0052] Figure 3 (c) is the energy spectrum of the surface elements of the carbon nanospheres. As shown in Figure 3 (d), the energy spectrum results are highly consistent with the infrared analysis results.​

Claims

1. A device for large-scale continuous preparation of carbon nanospheres from coal-based oil, characterized in that: The output port of the carbon source preparation tank is connected to one air inlet of the burner located on the synthesis reactor via a feed pump. A combustible gas pipe is connected to the other air inlet of the burner. A gas-solid separator is installed at the top of the synthesis reactor and a carbon ball conveyor is installed at the bottom. The solid outlet of the gas-solid separator is connected to the carbon ball conveyor, and a cooler is installed at the outlet of the carbon ball conveyor. The synthesis reactor is a shell with an inverted triangular longitudinal section, in which evenly distributed porous baffles are arranged along the gas path direction. The porous baffles are perpendicular to the side plates of the shell and form an acute angle with the top plate of the shell. The burner points perpendicularly to the porous baffles.

2. The apparatus for large-scale continuous preparation of carbon nanospheres from coal-based oil according to claim 1, characterized in that: The inverted triangle is an inverted isosceles triangle with a vertex angle α of 40° to 50°.

3. The apparatus for large-scale continuous preparation of carbon nanospheres from coal-based oil according to claim 1, characterized in that: The number of the porous baffles is 6 to 8, and the included angle between the porous baffles and the top plate of the shell is 55° to 60°.

4. The apparatus for large-scale continuous preparation of carbon nanospheres from coal-based oil according to claim 1, characterized in that: The perforated baffle has an opening rate of 75% to 85% and a hole diameter of 15 to 20 mm.

5. The apparatus for large-scale continuous preparation of carbon nanospheres from coal-based oil according to claim 1, characterized in that: The carbon ball conveyor is an electric screw conveyor.

6. The apparatus for large-scale continuous preparation of carbon nanospheres from coal-based oil according to claim 1, characterized in that: The gas-solid separator is a cyclone separator.

7. The method for preparing carbon nanospheres using the apparatus according to claim 1, characterized in that, Includes the following steps: Step 1. Preheat the carbon source preparation tank to 40℃~60℃, and add coal-based oil and diluent solvent to the carbon source preparation tank at a mass ratio of 10:1~8:1 and mix evenly to form a liquid carbon source; Step 2. The feed pump pressurizes the prepared liquid carbon source to 0.2-0.4 MPa and sends it to the burner. At the front end of the burner, it is atomized by a combustible gas flow from the pipeline at a pressure of 0.25-0.45 MPa and undergoes an oxygen-deficient combustion reaction to form carbon nuclei, which gradually grow into carbon spheres. The combustible gas flow is a gas during the start-up phase, and becomes a nitrogen-oxygen mixture after combustion. The volume concentration of O2 in the nitrogen-oxygen mixture is 15%-18%. Step 3. The flue gas carrying carbon balls flows through the porous baffles in a cross-flow manner. After being intercepted by inertia in stages, most of the carbon balls fall to the bottom of the synthesis reactor and enter the carbon ball conveyor. The flue gas carrying a small number of carbon balls enters the gas-solid separator for further separation. The separated carbon balls enter the carbon ball conveyor and are transported to the cooler. After being cooled by the cooler, they are discharged to form the final carbon ball product.

8. The method for preparing carbon nanospheres using the apparatus according to claim 7, characterized in that, The coal-based oil is one or a mixture of two or more of the following: medium- and low-temperature coal tar, high-temperature coal tar, direct coal liquefaction oil, hot melt oil of coal, solvent extraction oil of coal, and oxidized liquid products of coal.

9. The method for preparing carbon nanospheres using the apparatus according to claim 7, characterized in that, The diluent is one or a mixture of two or more of the following: n-pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, and gasoline fraction.

10. The method for preparing carbon nanospheres according to the apparatus of claim 7, characterized in that, The flow ratio of combustible gas flow to liquid carbon source in the burner is 14000:1 to 16000:1.

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