Device and method for continuously preparing carbon nanospheres from coal-based oil in macroscopic quantity

Abstract

The invention relates to a device and a method for continuously preparing carbon nanospheres from coal-based oil in a macroscopic quantity, an output port of a carbon source preparation tank is connected with a gas inlet of a burner positioned on a synthesis reactor through a feeding pump, another gas inlet of the burner is connected with a combustible gas pipe, a gas-solid separator is arranged at the top of the synthesis reactor, and a carbon sphere conveyor is arranged at the bottom of the synthesis reactor; a solid outlet of the gas-solid separator is connected with a carbon ball conveyor, and a cooler is arranged on an outlet of the carbon ball conveyor; the coal-based oil is adopted as the raw material, the liquid carbon source is obtained through solvent blending, and compared with a traditional method using pure chemicals as the carbon source, the raw material cost is greatly reduced. The carbon nanospheres are synthesized by adopting an oxygen-deficient combustion method, and a burner and a porous baffle are arranged in a synthesis reactor, so that the carbon spheres are synthesized by a one-step method, the synthesis steps are greatly simplified, the synthesis efficiency is improved, and the requirements of large-scale production are met.

Description

Technical Field

[0001] The invention belongs to the technical field of nano carbon sphere preparation, and specifically relates to a device and a method for preparing nano carbon spheres in large quantities and continuously using coal-based oil. Background Art

[0002] Nanocarbon spheres are a new type of nanomaterial, which are carbon spheres with a size of nanometers (<1000nm), 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 conductivity. They are widely used in electrode materials, catalysts or carriers in energy storage devices such as lithium-ion batteries, gas adsorption, storage and separation, pollutant adsorption in water treatment, and drug targeted delivery carriers. The methods for preparing nanocarbon spheres mainly include chemical vapor deposition, arc discharge and hydrothermal methods. Chemical vapor deposition and arc discharge methods have high requirements for equipment, and the process is difficult to control. Low molecular weight hydrocarbons are usually used as carbon sources, resulting in high costs. Although the hydrothermal method is simple to operate, the obtained carbon spheres are of high purity and good dispersibility and are widely used, but the carbon source required for the hydrothermal method is mostly pure chemicals, the raw material cost is also high, and the hydrothermal method has a long processing time and many steps. The synthesis efficiency is also low due to intermittent operation. For example, Chinese patent CN113582158A discloses a method for preparing carbon spheres in a polytetrafluoroethylene reactor using p-phenylenediamine as a carbon source, which requires treatment at 180°C for 3 hours; Chinese patent CN116477605A discloses a method for preparing carbon spheres in a stirred tank using p-phenylenediamine, hexamethylenetetramine, and polyoxyethylene polyoxypropylene ether block copolymer as carbon sources, which requires reaction for 24 hours; Chinese patent CN113648968A discloses a method for synthesizing carbon spheres using a hydrothermal method using monosaccharides or disaccharides as carbon sources and alcohol as a control agent, and the synthesis requires reaction at 130-170°C for 3-12 hours; Chinese patent CN117023552A discloses a method for preparing carbon spheres using intermittent operation in a high-pressure reactor, which requires 6 steps to obtain carbon spheres. It can be seen that the current preparation methods of nano-carbon spheres have the problems of high raw material costs and complex preparation steps, and most of them are carried out in an intermittent production manner in a reactor. The inability to produce continuously leads to a low output of the product, which seriously limits the application of nano-carbon spheres in emerging industries. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a device and method for continuously preparing nano-carbon spheres in large quantities from coal-based oil with simple structure, continuous operation, large production capacity and high working efficiency.

[0004] The technical solution adopted to solve the above technical problems is: a device for preparing nano carbon spheres in large quantities and continuously using coal-based oil, wherein the output port of the carbon source preparation tank is connected to an air inlet of a burner located on a synthesis reactor through a feed pump, and a combustible gas pipe is connected to the other air inlet of the burner, a gas-solid separator is arranged on the top of the synthesis reactor, and a carbon sphere conveyor is arranged on the bottom, the solid outlet of the gas-solid separator is connected to the carbon sphere conveyor, and a cooler is arranged on the outlet of the carbon sphere conveyor;

[0005] The synthesis reactor comprises a shell having an inverted triangle longitudinal section and evenly distributed porous baffles arranged along the gas path direction, the porous baffles being perpendicular to the two side plates of the shell and having an acute angle with the top plate of the shell; and the burner being perpendicular to the porous baffles.

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

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

[0008] Preferably, the porous baffle has an opening rate of 75% to 85% and a pore diameter of 15 to 20 mm.

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

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

[0011] The method for preparing nano carbon spheres by the device of the present invention comprises the following steps:

[0012] Step 1. Preheat the carbon source preparation tank to 40°C to 60°C, add coal-based oil and dilution solvent in a mass ratio of 10:1 to 8:1 into the carbon source preparation tank and mix them evenly 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 delivers it to the burner. At the front end of the burner, it is atomized by a combustible gas flow with a pressure of 0.25-0.45 MPa from the pipeline network and undergoes an oxygen-poor combustion reaction to form a carbon nucleus, which gradually grows to form a carbon ball. The combustible gas flow is a fuel gas in the startup stage and a nitrogen-oxygen mixed gas after combustion. The volume concentration of O2 in the nitrogen-oxygen mixed gas is 15%-18%;

[0014] Step 3. The flue gas carries the carbon balls in a cross-flow through the porous baffle. After being intercepted by inertia step by step, 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 amount of carbon balls enters the gas-solid separator for further separation. The separated carbon balls enter the carbon ball conveyor. The carbon ball conveyor transports the carbon balls to the cooler, where they are cooled and discharged to form the final carbon ball products.

[0015] Preferably, the coal-based oil is one or a mixture of two or more of medium- and 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 fractions.

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

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

[0019] The present invention uses coal-based oil as raw material and obtains liquid carbon source by solvent blending, which greatly reduces the cost of raw materials compared to the traditional method of using pure chemicals as carbon source. The oxygen-poor combustion method is used to synthesize nano carbon spheres. By setting a burner and a porous baffle inside the synthesis reactor, the one-step synthesis of carbon spheres is achieved, which greatly simplifies the synthesis steps, improves the synthesis efficiency, and meets the needs of large-scale production.

[0020] The device for preparing nano carbon spheres of the present invention has a simple structure, can realize continuous operation, improves work efficiency, and overcomes the problems of long time consumption and low yield caused by the intermittent method in the existing kettle synthesis process.

[0021] The present invention reduces the generation of harmful by-products through the oxygen-poor combustion method, which is more environmentally friendly. The prepared nano-carbon spheres have excellent properties such as high specific surface area, stable chemical properties and good electrical conductivity. They can be widely used in lithium-ion batteries, catalysts or carriers, gas adsorption storage and separation, water treatment, and drug targeted delivery carriers. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of the device for preparing nano carbon spheres in large quantities and continuously using coal-based oil according to the present invention.

[0023] Figure 2 It is a schematic diagram of the longitudinal section of the synthesis reactor 3.

[0024] Figure 3 This is a characterization diagram of the composition and morphology of carbon balls.

[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 ball conveyor 6, burner 7. DETAILED DESCRIPTION

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

[0027] Example 1

[0028] exist Figure 1 , 2 In the present embodiment, the coal-based oil large-scale continuous preparation of nano carbon spheres device, the output port of the carbon source preparation tank 1 is connected to the burner 7-air inlet 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 air inlet of the burner 7 is connected to a combustible gas pipe, the combustible gas pipe passes the combustible gas flow to the burner 7, the combustible gas flow is a gas in the startup stage, the gas is one of natural gas, liquefied petroleum gas, and coal gas, after burning, the combustible gas flow is switched to a nitrogen-oxygen mixed gas. A gas-solid separator 4 is fixedly installed on the top of the rear side of the synthesis reactor 3, and a carbon ball conveyor 6 is fixedly installed on 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 for conveying the generated carbon balls to the condenser 5 for cooling.

[0029] The synthesis reactor 3 of this embodiment includes a shell 3-1 and a porous baffle 3-2. The shell 3-1 with a longitudinal section of an inverted isosceles triangle is provided with 7 evenly distributed porous baffles 3-2 along the gas path direction. The vertex angle α of the inverted isosceles triangle is 46°. The porous baffle 3-2 is seamlessly connected to the two side plates of the shell 3-1 and is vertical, and is seamlessly connected to the top plate of the shell 3-1 and the angle between the porous baffle 3-2 and the top plate of the shell 3-1 is 58°. The opening rate of the porous baffle 3-2 is 80%, and the aperture is 18mm. The porous baffle 3-2 is used to separate the carbon balls in the flue gas flow step by step by impact, and the burner 7 located at the front side is vertically pointed to the porous baffle 3-2. The synthesis reactor 3 is designed to have an isosceles triangle structure in the longitudinal section. On the one hand, it is convenient for the direct splicing and manufacturing of the reactor, simplifies the structure, and reduces the manufacturing difficulty. It is also conducive to the carbon balls intercepted by the porous baffle 3-2 to quickly fall to the bottom of the synthesis reactor, maintain a certain material seal, and realize the stable and continuous operation of the synthesis reaction device.

[0030] The method for preparing nano-carbon spheres by using the coal-based oil large-scale continuous preparation device of nano-carbon spheres in this embodiment comprises the following steps:

[0031] Step 1. Preheat the carbon source preparation tank 1 to 50°C, add the coal-based oil and the dilution solvent into the carbon source preparation tank 1 at a mass ratio of 9:1 and mix them evenly to form a liquid carbon source. The coal-based oil is one or a mixture of two or more selected from 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 liquid oxidation product of coal. The dilution solvent is one or a mixture of two or more selected from n-pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, and gasoline fraction.

[0032] Step 2. The feed pump 2 pressurizes the prepared liquid carbon source to 0.2-0.4 MPa and delivers it to the burner 7. At the front end of the burner 7, it is atomized by a combustible gas flow with a pressure of 0.25-0.45 MPa from the pipeline and undergoes an oxygen-poor combustion reaction to form carbon nuclei, which gradually grow into carbon balls. The combustible gas flow is fuel gas in the startup stage and becomes a nitrogen-oxygen mixed gas after combustion. The flow ratio of the nitrogen-oxygen mixed gas to the liquid carbon source is 15000:1, and the volume concentration of O2 in the nitrogen-oxygen mixed gas is 16%.

[0033] Step 3. The flue gas carries the carbon balls in a cross-flow through the porous baffle 3-2. After being intercepted by inertia step by step, most of the carbon balls fall to the bottom of the synthesis reactor 3 and enter the carbon ball conveyor 6. The flue gas carrying a small amount of carbon balls enters the gas-solid separator 4 for further separation. The separated carbon balls enter the carbon ball conveyor 6. The carbon ball conveyor 6 conveys the carbon balls to the cooler, where they are cooled and discharged to form the final carbon ball products.

[0034] Example 2

[0035] In this embodiment, the synthesis reactor 3 includes a shell 3-1 and a porous baffle 3-2. Six evenly distributed porous baffles 3-2 are arranged in the shell 3-1 with a longitudinal section of an inverted isosceles triangle along the gas path direction. The vertex angle α of the inverted isosceles triangle is 40°. The porous baffle 3-2 is seamlessly connected to the two side plates of the shell 3-1 and is perpendicular, and is seamlessly connected to the top plate of the shell 3-1 and the angle between the porous baffle 3-2 and the top plate of the shell 3-1 is 55°. The opening rate of the porous baffle 3-2 is 75%, and the aperture is 15 mm. The porous baffle 3-2 is used to separate the carbon balls in the flue gas flow step by step by impact, and the burner 7 located on the front side is vertically pointed to the porous baffle 3-2.

[0036] Other components and their connection relationships are the same as those in Example 1.

[0037] The method for preparing nano-carbon spheres by using a large-scale continuous preparation device of nano-carbon spheres using coal-based oil in this embodiment is as follows:

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

[0039] Step 2. The feed pump 2 pressurizes the prepared liquid carbon source to 0.2-0.4 MPa and delivers it to the burner 7. At the front end of the burner 7, it is atomized by a combustible gas flow with a pressure of 0.25-0.45 MPa from the pipeline and undergoes an oxygen-poor combustion reaction to form carbon nuclei, which gradually grow into carbon balls. The combustible gas flow is fuel gas in the startup stage and becomes a nitrogen-oxygen mixed gas after combustion. The flow ratio of the nitrogen-oxygen mixed gas to the 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 those in Example 1.

[0041] Example 3

[0042] In this embodiment, the synthesis reactor 3 includes a shell 3-1 and a porous baffle 3-2. The shell 3-1, whose longitudinal section is an inverted isosceles triangle, is provided with 8 evenly distributed porous baffles 3-2 along the gas path direction. The vertex angle α of the inverted isosceles triangle is 50°. The porous baffle 3-2 is seamlessly connected to the two side plates of the shell 3-1 and is perpendicular to it. It is seamlessly connected to the top plate of the shell 3-1 and the angle between it and the top plate of the shell 3-1 is 60°. The opening rate of the porous baffle 3-2 is 85%, and the aperture is 20 mm. The porous baffle 3-2 is used to separate the carbon balls in the flue gas flow step by step by impact. The burner 7 located on the front side is vertically pointed to the porous baffle 3-2.

[0043] Other components and their connection relationships are the same as those in Example 1.

[0044] The method for preparing nano-carbon spheres by using a large-scale continuous preparation device of nano-carbon spheres using coal-based oil in this embodiment is as follows:

[0045] Step 1. Preheat the carbon source preparation tank 1 to 60° C., add coal-based oil and dilution solvent into the carbon source preparation tank 1 at a mass ratio of 8:1 and mix them evenly 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 delivers it to the burner 7. At the front end of the burner 7, it is atomized by a combustible gas flow with a pressure of 0.25-0.45 MPa from the pipeline and undergoes an oxygen-poor combustion reaction to form carbon nuclei, which gradually grow into carbon balls. The combustible gas flow is fuel gas in the startup stage and becomes a nitrogen-oxygen mixed gas after combustion. The flow ratio of the nitrogen-oxygen mixed gas to the 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 those in Example 1.

[0048] experiment

[0049] In order to verify the beneficial effects of the present invention, the following experiment was conducted using the method for preparing nano-carbon spheres in Example 1.

[0050] Nanocarbon spheres were prepared in the laboratory using coal tar obtained by pyrolysis of Shenfu coal as a carbon source. The method for preparing nanocarbon spheres in Example 1 was followed to obtain nanocarbon spheres. The nanocarbon spheres were characterized in detail. The results are as follows: Figure 3 shown. Figure 3 (a) Scanning electron microscopy results show that the carbon nanospheres are uniform, with a single particle size of approximately 80 to 100 nm. Figure 3 (b) The nanocarbon spheres have a wave number of 3488 cm -1 The absorption at 2819cm indicates the presence of some hydroxyl structures; -1 and 2734cm -1 The two peaks represent alkyl side chains. Since these two peaks are weak, it means that the number of alkyl side chains is small; 1656cm -1 、1610cm -1 、859cm -1 、780cm -1 、684cm -1 These peaks are all absorptions of aromatic rings. The strong peaks indicate that the carbon sphere has a high aromaticity. -1 and 1355cm -1 The two peaks represent the absorption vibrations of the methyl and ketone groups outside the aromatic ring, respectively, indicating that there are a small number of active functional groups such as methyl and ketone groups outside the aromatic core of the carbon sphere.

[0051] The above infrared analysis results show that the carbon spheres prepared by the present invention have high aromaticity, a large number of active functional groups distributed outside the aromatic rings, and many reaction active sites, and are particularly suitable as electrode materials, catalysts or carriers, and gas adsorption, storage and separation materials.

[0052] Figure 3 (c) is the energy spectrum of the elements on the surface of the carbon sphere. It can be seen that the surface of the carbon sphere prepared by the present invention is mainly composed of carbon elements, followed by oxygen elements. The carbon element accounts for about 92% and the oxygen element accounts for about 8%. Figure 3 (d), the energy spectrum results are highly consistent with the infrared analysis results.

Claims

1. A device for continuous large-scale preparation of nano-carbon spheres using coal-based oil, characterized in that: The output port of the carbon source preparation tank is connected to an air inlet of a burner located on the synthesis reactor through a feed pump, and a combustible gas pipe is connected to the other air inlet of the burner. A gas-solid separator is arranged on the top of the synthesis reactor, and a carbon ball conveyor is arranged on the bottom. The solid outlet of the gas-solid separator is connected to the carbon ball conveyor, and a cooler is arranged on the outlet of the carbon ball conveyor; The synthesis reactor comprises a shell having an inverted triangle longitudinal section and evenly distributed porous baffles arranged along the gas path direction, the porous baffles being perpendicular to the two side plates of the shell and having an acute angle with the top plate of the shell; and the burner being perpendicular to the porous baffles.

2. The device for preparing nano carbon spheres in large quantities by continuous use of coal-based oil according to claim 1, characterized in that: The inverted triangle is an inverted isosceles triangle, and the vertex angle α is 40° to 50°.

3. The device for preparing nano carbon spheres in large quantities by continuous use of coal-based oil according to claim 1, characterized in that: The number of the porous baffles is 6 to 8, and the angle between the porous baffles and the top plate of the shell is 55° to 60°.

4. The device for preparing nano carbon spheres in large quantities by continuous use of coal-based oil according to claim 1, characterized in that: The opening rate of the porous baffle is 75% to 85%, and the pore diameter is 15 to 20 mm.

5. The device for preparing nano carbon spheres in large quantities by continuous use of coal-based oil according to claim 1, characterized in that: The carbon ball conveyor is an electric screw conveyor.

6. The device for preparing nano carbon spheres in large quantities by continuous use of coal-based oil according to claim 1, characterized in that: The gas-solid separator is a cyclone separator.

7. The method for preparing nano carbon spheres according to the device of claim 1, characterized in that: The following steps are involved: Step 1. Preheat the carbon source preparation tank to 40°C to 60°C, add coal-based oil and dilution solvent into the carbon source preparation tank 1 at a mass ratio of 10:1 to 8:1, and mix them 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 delivers it to the burner. At the front end of the burner, it is atomized by a combustible gas flow with a pressure of 0.25-0.45 MPa from the pipeline network and undergoes an oxygen-poor combustion reaction to form a carbon nucleus, which gradually grows to form a carbon ball. The combustible gas flow is a fuel gas in the startup stage and a nitrogen-oxygen mixed gas after combustion. The volume concentration of O2 in the nitrogen-oxygen mixed gas is 15%-18%; Step 3. The flue gas carries the carbon balls in a cross-flow through the porous baffle. After being intercepted by inertia step by step, 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 amount of carbon balls enters the gas-solid separator for further separation. The separated carbon balls enter the carbon ball conveyor. The carbon ball conveyor transports the carbon balls to the cooler, where they are cooled and discharged to form the final carbon ball products.

8. The method for preparing nano carbon spheres according to the device of claim 7, characterized in that: The coal-based oil is one of medium and low temperature coal tar, high temperature coal tar, coal direct liquefaction oil, coal hot melt oil, coal solvent extraction oil, coal oxidation liquid product or a mixture of two or more thereof.

9. The method for preparing nano carbon spheres according to the device of claim 7, characterized in that: The dilution solvent is one of n-pentane, cyclopentane, n-hexane, cyclohexane, n-heptane and gasoline fractions, or a mixture of two or more thereof.

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

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