Fullerene production apparatus and production method

Abstract

This apparatus is provided with: a reaction furnace (2) in which a fullerene is produced by incomplete combustion of a starting material gas containing a hydrocarbon; a first injection section (9) which is arranged on the upstream end side of the reaction furnace (2) and allows the starting material gas to incompletely combust while injecting the starting material gas and a first oxygen-containing gas toward the downstream end side of the reaction furnace (2); and a second injection section (25a) which is arranged on the upstream end side of the reaction furnace (2) so as to surround the first injection section (9) and injects a second oxygen-containing gas or an inert gas toward the downstream end side of the reaction furnace (2) along a side wall (2a) of the reaction furnace (2) between the upstream end side and the downstream end side.

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for producing fullerenes. This application claims priority based on Japanese Patent Application No. 2021-214242, filed on December 28, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] A known method for producing fullerenes is a combustion method in which fullerenes are produced by incompletely combusting a raw material gas containing hydrocarbons (hereinafter also referred to as "raw material gas") in a reactor (see, for example, Patent Document 1). This combustion method makes it possible to mass-produce fullerenes contained in soot-like matter produced by incomplete combustion of the raw material gas at low cost. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-192318 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when fullerenes are continuously produced by the combustion method, a portion of the soot-like material produced in the reactor adheres to the reactor walls and remains in the reactor. The thickness of the adhered soot-like material increases as the operating time of the fullerene production apparatus increases. If the thick soot-like material blocks the flow path between the raw material supply means and the outlet in the reactor, the incomplete combustion of the raw material may not continue.

[0005] Therefore, when fullerenes are continuously produced by the combustion method, it is necessary to periodically stop the operation of the fullerene production apparatus and perform maintenance work to remove the soot-like material adhering to the walls of the reactor. For example, the maintenance work involves waiting until the temperature inside the reactor of the production apparatus that has been stopped drops to room temperature, opening the reactor, and physically removing the soot-like material adhering to the walls of the reactor. Such maintenance work requires a long time and is laborious.

[0006] The present invention has been proposed in view of the above-mentioned conventional circumstances, and aims to provide a fullerene production apparatus and production method that can improve the efficiency of fullerene production by suppressing adhesion of soot-like matter generated in a reactor to the reactor walls or by easily removing soot-like matter that has adhered to the reactor walls. [Means for solving the problem]

[0007] A first aspect of the present invention provides the following apparatus for producing fullerenes. (1) a reactor for producing fullerenes by incomplete combustion of a raw material gas containing hydrocarbons; a first injection unit that is disposed at an upstream end of the reactor and that injects the raw material gas and a first oxygen-containing gas toward a downstream end of the reactor while causing incomplete combustion of the raw material gas in the reactor; a second injection unit disposed on the upstream end side of the reactor so as to surround the first injection unit, and which injects a second oxygen-containing gas or an inert gas toward the downstream end side of the reactor along a side wall of the reactor between the upstream end side and the downstream end side. The fullerene device according to the first aspect of the present invention preferably has the following features [2] to

[11] . It is also preferable to combine two or more of the following features. (2) The fullerene manufacturing apparatus according to the preceding paragraph (1), characterized in that when the reactor is viewed from a longitudinal section in a direction from the upstream end side to the downstream end side, the tip of the second injection part is located in the same cross section of the reactor as the tip of the first injection part, or the tip of the second injection part is located upstream of the tip of the first injection part. (3) The side wall of the reactor is cylindrical; the second injection portion includes a second injection port portion having a ring-shaped tip surface, The fullerene production apparatus according to the preceding item (2), characterized in that, when the radial thickness dimension of the tip surface of the second injection port portion is d1 and the inner radius of the reactor is D, d1 / D is 0.01 to 0.40. (4) The fullerene production apparatus according to the preceding paragraph (3), characterized in that, when the radial distance between the outer periphery of the tip surface of the second injection port portion and the inside of the side wall of the reactor is d2, d2 / D is 0.00 to 0.10. (5) The fullerene production apparatus according to the preceding paragraph (3) or (4), characterized in that the first injection part has a cylindrical first injection port part, a first injection port is provided at the tip face of the first injection part, and when the radius of the first injection port part is d3, d3 / D is 0.40 to 0.96. (6) The fullerene production apparatus according to the preceding paragraph (5), characterized in that, when the radial distance between the outer periphery of the first injection port portion and the inner periphery of the tip surface of the second injection port portion is d4, d4 / D is 0.01 to 0.25. (7) The ring-shaped tip surface of the second injection port portion has a plurality of second injection ports each having a diameter of 0.1 mm to 5.0 mm, the second injection ports are uniformly arranged on the tip surface of the second injection port portion, The fullerene manufacturing apparatus according to any one of the preceding paragraphs (3) to (6), characterized in that the ratio of the total opening area of ​​the second injection nozzle to the tip surface area of ​​the second injection nozzle portion is 10% to 95%. (8) The fullerene manufacturing apparatus according to any one of the above (3) to (7), wherein the second injection port portion is made of a porous material. (9) The fullerene manufacturing apparatus according to any one of (3) to (6) above, wherein the second injection port of the second injection port unit is a ring-shaped slit in a plan view. (10) The flow rate of the second oxygen-containing gas or the inert gas injected from the second injection port is set to 1 / cm2 of the tip surface area of ​​the second injection port. 2 The fullerene production apparatus according to any one of the above items (3) to (9), characterized in that the flow rate is 0.1 to 10.0 NL / min per minute. (11) A cylindrical porous body is provided on the upstream end side of the reactor so as to cover or fill the tip of the first injection part and the tip of the second injection part, The fullerene production apparatus according to any one of the preceding items (1) to (10), characterized in that the thickness of the porous body from the tips located downstream of the first injection part and the second injection part to the end located downstream of the cylindrical porous body is 1 to 50 mm in the direction from the upstream end side to the downstream end side. A second aspect of the present invention provides the following method for producing fullerenes. (12) A fullerene production step of producing a soot-like substance containing fullerenes in a reactor by incomplete combustion of a raw material gas containing hydrocarbons, In the fullerene production step, the raw material gas and a first oxygen-containing gas are injected from a first injection unit disposed on the upstream end side of the reactor toward a downstream end side of the reactor, while the raw material gas is incompletely combusted in the reactor, and A method for producing fullerenes, characterized in that a second oxygen-containing gas or an inert gas is injected from a second injection part arranged to surround the first injection part on the upstream end side toward the downstream end side along a side wall of a reactor located between the upstream end side and the downstream end side. A third aspect of the present invention provides the following method for producing fullerenes. (13) a fullerene production step in which a hydrocarbon-containing raw material gas and a first oxygen-containing gas are injected from a first injection unit disposed at an upstream end of the reactor toward a downstream end thereof, while the raw material gas is incompletely combusted to produce a soot-like substance containing fullerenes; a soot-like substance removal step of, after the fullerene production step, injecting a second oxygen-containing gas or an inert gas from a second injection part, which is arranged so as to surround the first injection part on the upstream end side of the reactor, toward the downstream end side along a side wall of the reactor between the upstream end side and the downstream end side, to remove the soot-like substance adhering to the side wall of the reactor. [Effects of the Invention]

[0008] As described above, according to the present invention, it is possible to improve the efficiency of fullerene production by suppressing the adhesion of soot-like matter generated in the reactor to the reactor walls, or by easily removing the soot-like matter that has adhered to the reactor walls. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a configuration diagram showing an example of a fullerene production apparatus 1 according to an embodiment of the present invention. [Figure 2] 1 is a schematic vertical cross-sectional view showing the configuration of a reactor 2 equipped with a burner 9 and a gas inlet 10 according to one embodiment of the present invention. [Figure 3] 3 is a schematic diagram illustrating the burner 9, the second injection part 25a, and the side wall 2a when the reactor 2 is cut along the broken line AA in FIG. 2 and viewed from the cross section toward the upper wall part 2b. [Figure 4] 1 is a schematic vertical cross-sectional view showing the configuration of a reactor 2 equipped with a burner 9 and a gas inlet 10 according to one embodiment of the present invention. [Figure 5] 5 is a schematic diagram illustrating the burner 9, the second injection part 25a, and the side wall 2a when the reactor 2 is cut along the dashed line AA in FIG. 4 and viewed from the cross section toward the upper wall part 2b. [Figure 6] 2 is a schematic vertical cross-sectional view showing the configuration of a reactor 2 equipped with a porous body 28. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, preferred examples of the fullerene production apparatus and production method to which the present invention is applied will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments. For example, the number, shape, type, position, quantity, ratio, material, member, configuration, etc. can be added, omitted, substituted, or changed within the scope of the present invention. The drawings used in the following description may show characteristic parts in a schematic manner for convenience in order to make the features easier to understand, and the dimensional ratios of each component may not necessarily be the same as the actual ones.

[0011] (Fullerene manufacturing equipment) The fullerene production apparatus of this embodiment produces fullerenes by incomplete combustion of a raw material containing hydrocarbons. 60 Fullerene (C 60 ), C 70 Fullerene (C 70 ), C 76 , C 78 , C 84 , C 90 , C 96 Incomplete combustion refers to the combustion of a substance (such as the raw material) in a state where there is insufficient oxygen.

[0012] 1 is a schematic diagram showing a preferred example of a fullerene production apparatus 1. The fullerene production apparatus 1 includes a reactor 2 that produces a soot-like material containing fullerenes by incomplete combustion of a raw material gas containing hydrocarbons, a recovery mechanism 3 that recovers the soot-like material produced in the reactor 2, a cooling mechanism 4 that cools the gas that has passed through the recovery mechanism 3, and a decompression mechanism 5 that reduces the pressure inside the reactor 2 while sucking in the gas cooled by the cooling mechanism 4. The term "mechanism" may refer to a device, an instrument, or the like.

[0013] In addition, this fullerene manufacturing apparatus 1 has a first pipe 6 connecting the reactor 2 and the recovery mechanism 3, a second pipe 7 connecting the recovery mechanism 3 and the cooling mechanism 4, and a third pipe 8 connecting the cooling mechanism 4 and the pressure reduction mechanism 5.

[0014] The reactor 2 has a cylindrical side wall 2a, an upper wall portion 2b closing the upper end (upstream end) of the side wall 2a, and a lower wall portion 2c closing the lower end (downstream end) of the side wall 2a, and is disposed in a vertically upright state. The cross section of the reactor 2 is circular, as will be described later.

[0015] The material of the reactor 2 can be selected arbitrarily, and examples thereof include heat-resistant materials such as zirconia (ZrO), tungsten (W), tantalum (Ta), platinum (Pt), titanium (Ti), titanium nitride (TiN), alumina (AlO), silicon carbide (SiC), etc. At least a portion of the outside and inside of the reactor 2 may be lined with a heat insulating material such as alumina firebricks or alumina monolithic refractory material.

[0016] Furthermore, the reactor 2 is preferably arranged in the vertical direction as described above, since this reduces the influence of soot-like matter accumulation. When the reactor 2 is arranged vertically, it is preferable to supply the raw material gas from above. On the other hand, the reactor 2 can also be arranged, for example, horizontally or at an angle.

[0017] The first pipe 6 is connected to an outlet 30d (hereinafter referred to as "exhaust gas outlet 30d") provided in the lower wall 2c of the reactor 2 for discharging exhaust gas. Meanwhile, a burner 9, which is a first injection unit, and a gas introduction unit 10 are provided on the upper wall 2b side of the reactor 2. As will be described later, the first injection unit injects the raw material gas and the first oxygen-containing gas (sometimes referred to as injection I). In the reactor 2, the raw material gas and the first oxygen-containing gas injected from the pipe provided in the first injection unit (burner 9) are incompletely combusted within the reactor 2, thereby producing a soot-like substance containing fullerenes.

[0018] In addition to the injection of the above gas, a second oxygen-containing gas or an inert gas is injected (sometimes referred to as injection II) from the gas inlet 10 along the side wall 2a of the reactor 2. This makes it possible to prevent soot-like matter from adhering to the side wall 2a and / or to remove soot-like matter adhering to the side wall 2a from the side wall 2a.

[0019] High-temperature exhaust gas containing soot produced by incomplete combustion of the raw material gas and the first oxygen-containing gas, carbon monoxide, carbon dioxide, water vapor, the second oxygen-containing gas, inert gas, etc. passes through the first pipe 6 and reaches the recovery mechanism 3.

[0020] The recovery mechanism 3 has a collector 12 containing a filter 11, a tank 14 connected to the upper end (one end) of the collector 12 via an electromagnetic valve 13, and a discharge valve 15 provided on the lower end (other end) of the collector 12.

[0021] As shown in FIG. 1, the first pipe 6 is connected to the side of the upper part of the collector 12. The second pipe 7 is connected to the upper part of the collector 12. A valve is provided on the second pipe 7. For example, a sintered metal filter is used as the filter 11. The solenoid valve 13 is connected to a branch of the second pipe 7. A tank 14 stores a high-pressure inert gas such as nitrogen gas (N2) or argon gas (Ar).

[0022] In the recovery mechanism 3, soot-like matter contained in the exhaust gas supplied from the first pipe 6 is collected by the filter 11. After the soot-like matter has been collected, the solenoid valve 13 is periodically opened to inject inert gas from the tank 14 toward the collector 12. This injection causes the soot-like matter adhering to the filter 11 to fall off. Thereafter, the discharge valve 15 is opened, allowing the soot-like matter accumulated in the collector 12 to be collected via the discharge valve 15.

[0023] The cooling mechanism 4 has a structure identical to or similar to that of a normal heat exchanger. One end (upper end) of the cooling mechanism 4 is connected to the second pipe 7, and the other end (lower end) is connected to the third pipe 8.

[0024] The cooling mechanism 4 cools the gas that has passed through the recovery mechanism 3. The cooling mechanism 4 also liquefies unreacted hydrocarbons and water vapor in the gas, and can discharge them from a drain 16 provided at the bottom.

[0025] In addition to the cooling mechanism 4, the first pipe 6 may be configured to be cooled since the exhaust gas passing through the first pipe 6 is at a high temperature.

[0026] The pressure reducing mechanism 5 is preferably composed of a vacuum pump, and sucks the gas cooled by the cooling mechanism 4 through the third pipe 8. By this suction, a negative pressure is generated between the pressure reducing mechanism 5 and the reactor 2, and the soot-like matter produced in the reactor 2 can be discharged to the recovery mechanism 3 side through the first pipe 6.

[0027] Examples of hydrocarbons contained in the raw material gas used to produce fullerenes include aromatic hydrocarbons having 6 to 15 carbon atoms, such as toluene, benzene, xylene, naphthalene, methylnaphthalene, anthracene, and phenanthrene; coal-based hydrocarbons, such as creosote oil and carboxylic acid oil; ethylenically unsaturated hydrocarbons; acetylenically unsaturated hydrocarbons; and aliphatic saturated hydrocarbons, such as pentane and hexane. These hydrocarbons may be used alone or in combination of two or more. Among the hydrocarbons listed above, aromatic hydrocarbons are preferred for the raw material gas. The raw material gas may be diluted with an inert gas, such as nitrogen or argon, as needed. The ratio of hydrocarbons contained in the raw material gas may be selected as needed. The hydrocarbons may be in a raw material gas state before entering the first injection unit 9 or the burner holder 23. The hydrocarbons may be in a liquid state before entering the first injection unit.

[0028] The first oxygen-containing gas and the second oxygen-containing gas are gases containing oxygen gas, such as oxygen gas and air. The ratio of oxygen contained in the oxygen-containing gas may be selected as needed. The first oxygen-containing gas and the second oxygen-containing gas may be the same or different. The first oxygen-containing gas used for producing fullerenes may be supplied to the reactor 2 separately from the raw material gas, or may be mixed with the raw material gas in advance and then supplied to the reactor 2.

[0029] In the reactor 2, an inert gas not containing oxygen gas may be supplied in place of the second oxygen-containing gas in injection II. Here, the inert gas is not particularly limited as long as it does not react with the generated soot and exhaust gas. Examples include nitrogen gas, argon gas, and carbon dioxide.

[0030] Next, the specific configurations of the burner 9 (first injection part) and the gas introduction part 10 provided in the fullerene production apparatus 1 will be described with reference to FIGS.

[0031] 2 and 4 are longitudinal cross-sectional views showing examples of the configuration of the reactor 2 equipped with the burner 9 and the gas inlet 10. Figures 3 and 5 are cross-sectional views of the reactor 2 taken along the dashed line AA in Figures 2 and 4, respectively, illustrating the burner 9, a second injection part 25a (described later), and the side wall 2a as viewed from the cross section toward the upper wall 2b side.

[0032] The fullerene production apparatus 1 of this embodiment includes a burner 9 and a gas introduction unit 10, as shown in Fig. 2. The burner 9 supplies gas used in the production of fullerenes (injection I). The gas introduction unit 10 supplies gas used to prevent sooty matter from adhering to the side surfaces of the furnace wall and to remove the sooty matter that has adhered (injection II).

[0033] Burner 9, which is the first injection part, has a cylindrical burner holder 23 with a top that is attached while penetrating the upper wall 2b of reactor 2. A portion of burner holder 23 protrudes into reactor 2. Inside burner holder 23, there are preferably provided, from the top, a premixing chamber 23a, a pressure accumulator chamber 23b, and a cylindrical first injection port 23c. In addition, a pipe 24a for introducing a raw material gas and a pipe 24b for introducing a first oxygen-containing gas are connected to the top of burner holder 23 via a flashback prevention device (not shown).

[0034] The pipe 24a is preferably provided with a first flow meter 35a for controlling the flow rate of the raw material gas (or liquid hydrocarbons). When liquid hydrocarbons are used, the pipe 24a may be provided with a gasification device, such as a heating device, between the first flow meter 35a and the upper part of the burner holder 23 for gasifying the liquid hydrocarbons.

[0035] Pipe 24b is provided with first flowmeter 35b that controls the flow rate of the first oxygen-containing gas. The flow rate adjustment unit has first flowmeters 35a and 35b. Using first flowmeters 35a and 35b, the flow rate adjustment unit can adjust the ratio A1 of the number of carbon atoms in the source gas to the number of oxygen atoms in the first oxygen-containing gas (number of carbon atoms in source gas / number of oxygen atoms in first oxygen-containing gas) to 0.60 to 2.00, and supply the source gas and the first oxygen-containing gas to first injection port unit 23c within a preferred range.

[0036] The first flow meters 35a and 35b may be any type that can adjust the flow rates of the raw material gas (or liquid hydrocarbon) and the first oxygen-containing gas to predetermined levels, and may be, for example, a commercially available mass flow controller.

[0037] In the premixing chamber 23a, the raw material gas introduced from the pipe 24a and the first oxygen-containing gas introduced from the pipe 24b are uniformly mixed. The pressure accumulation chamber 23b accumulates the raw material gas and the first oxygen-containing gas (hereinafter also referred to as "mixed gas") mixed in the premixing chamber 23a at a predetermined pressure.

[0038] The first jetting port portion 23c has one or more first jetting ports 21a. The first jetting port portion 23c may have, for example, a cylindrical shape. The mixed gas accumulated in the pressure accumulator chamber 23b is jetted from the first jetting ports 21a toward the lower wall portion 2c (jet I). The first jetting port portion 23c is preferably a portion where a large number of first jetting ports 21a are arranged together. For example, the first jetting port portion 23c may have a large number of first jetting ports 21a that are approximately circular in plan view and have a diameter of 0.1 mm to 5.0 mm. The multiple jetting ports 21a can be arbitrarily selected and may be arranged randomly or regularly. The jetting ports 21a may be formed by holes in the porous body, or may be openings in recesses formed by processing the surface of the porous body, or openings located below through-holes extending in the vertical direction formed by processing the porous body. Examples include porous ceramic sintered bodies, porous bodies made with a 3D printer, and injection nozzles with multiple through-holes made by post-processing. When the first ejection port portion 23c is formed by a large number of first ejection ports 21a, the ratio of the total opening area of ​​the first ejection ports 21a to the area (total area) of the tip face of the first ejection port portion 23c is preferably 10% to 95%, and more preferably 50% to 95%. The first ejection port portion 23c can be made of a porous body having a plurality of first ejection ports 21a, such as a porous ceramic sintered body or a sintered body of metal powder.

[0039] When the radius of the first injection port portion 23c is d3 and the inner radius of the reactor 2 is D, d3 / D is preferably 0.40 to 0.96, more preferably 0.50 to 0.95, and even more preferably 0.60 to 0.94. Within this range, a soot-like material containing fullerenes can be efficiently produced. The ratio may be 0.63 to 0.90, 0.64 to 0.85, 0.65 to 0.80, 0.66 to 0.75, or 0.67 to 0.70, for example.

[0040] In addition, in this embodiment, the premixing chamber 23a, the pressure accumulating chamber 23b, and the first injection port portion 23c are provided inside the burner holder 23, but the premixing chamber 23a may be omitted. Furthermore, if necessary, the premixing chamber 23a and the pressure accumulating chamber 23b may be provided outside the burner holder 23. hand Good too.

[0041] 2, the gas introduction section 10 has a cylindrical second injection section 25a surrounding the first injection section (burner 9) and a connection pipe 27 connected to the second injection section 25a. The second injection section 25a injects gas (injection II) to prevent the deposition or adhesion of sooty matter on the furnace wall and to remove sooty matter that has adhered or accumulated on the inner wall.

[0042] Furthermore, the tip of the second injection part 25a is located at the same cross section (same height position) as the tip of the first injection part (burner 9) when viewed in a vertical cross section passing through the center of the reactor 2 in the direction from the upper wall part 2b side (upstream end side) to the lower wall part 2c side (downstream end side) of the reactor 2. In other words, the tip of the first injection part and the tip of the second injection part 25a are located side by side in the horizontal direction, or are located upstream (closer to the upper wall part 2b) than the tip of the first injection part (burner 9). With such a structure, adhesion of soot-like matter to the periphery of the burner holder 23 can be effectively suppressed.

[0043] The second injection part 25a has a second injection port part 25b whose tip surface is ring-shaped in a plan view. The second injection part 25a may have a cylindrical outer wall and an inner wall arranged concentrically. The space between the outer wall and the inner wall may have any shape selected, and a member having any shape and material selected may be inserted between them. The cylindrical outer wall may also serve as the side wall of the reactor or a portion thereof. The side wall of the reactor, the side wall of the second injection part 25a, and the side wall of the burner 9 may be arranged concentrically. When the radial thickness dimension (opening width) of the tip surface of the second injection port part 25b is d1, the ratio d1 / D, relative to the inner radius D of the reactor 2, is preferably 0.01 to 0.40, more preferably 0.01 to 0.30, and even more preferably 0.01 to 0.20. Within this range, adhesion of soot-like substances can be prevented and the effect on fullerene production is minimal. The ratio may be 0.03 to 0.25, 0.05 to 0.18, 0.07 to 0.15, or 0.10 to 0.13.

[0044] The shape, material, and configuration of the second jetting port 25b provided in the second jetting part 25a can be selected arbitrarily. For example, it may be doughnut-shaped in a plan view. Gas flows through the second jetting port 25b. The second jetting port 25b preferably has a structure in which a large number of second jetting ports 22a are arranged in a cluster on the tip end surface, as shown in FIG. 3, for example. An example of the configuration of the second jetting port 25b is one in which a large number of second jetting ports 22a, each having a diameter of 0.1 mm to 5.0 mm and being substantially circular in a plan view, are uniformly arranged on the tip end surface (in this example, the ring-shaped tip end surface) of the second jetting part 25a. When the second jetting port portion 25b has a shape or structure in which a large number of second jetting ports 22a are arranged, the ratio of the total opening area of ​​the second jetting ports 22a to the area of ​​the tip surface of the second jetting port portion 25b, i.e., the area of ​​the tip surface of the second jetting port portion 25a, is preferably 10% to 95%, more preferably 50% to 95%. When the second jetting port 22a has multiple openings, the arrangement of the openings can be selected arbitrarily, and they may be arranged randomly or at equal intervals. Specific examples of the second jetting port portion 25b include a porous body having multiple second jetting ports 22a, such as a porous ceramic sintered body or a sintered body of metal powder. In this case, it is more preferable that d1 / D is 0.05 to 0.20.

[0045] The shape of the tip surface of second jetting port portion 25b may be a ring-shaped slit (ring-shaped opening), for example, as shown in Fig. 5. That is, second jetting port portion 25b may be a hollow flow path. Second jetting port 22a of second jetting port portion 25b shown in Fig. 5 is a ring-shaped slit provided in the tip surface of second jetting portion 25a. In this case, d1 / D is more preferably 0.01 to 0.15, and particularly preferably 0.01 to 0.10.

[0046] A second oxygen-containing gas or an inert gas is injected from the second injection port 22a of the second injection port portion 25b along the side wall 2a toward the lower wall portion 2c side (downstream end side) of the reactor 2 (injection II).

[0047] When the radial distance between the outer periphery of the ring-shaped opening (the outer periphery of the ring-shaped opening) as the tip surface of the second injection port portion 25b and the inside (inner surface) of the side wall 2a of the reactor 2 is d2, where D is the inner radius of the reactor 2, the ratio d2 / D is preferably 0.00 to 0.10, more preferably 0.00 to 0.07, and even more preferably 0.00 to 0.05. Within this range, the effect of preventing adhesion of soot-like matter to the side wall 2a or removing adhered soot-like matter is improved. The ratio may be 0.00 to 0.04, 0.01 to 0.03, or 0.02 to 0.03, for example.

[0048] From the viewpoint of downsizing the reactor 2, when the radial distance between the first jet nozzle 23c and the inner periphery of the ring-shaped tip surface of the second jet nozzle 25b (the inner periphery of the ring-shaped opening) is d4, where D is the inner radius of the reactor 2, the ratio d4 / D is preferably 0.01 to 0.25, and more preferably 0.01 to 0.20. The thicknesses of the burner holder 23 and the portions of the second jet nozzle 25a other than the second jet nozzle 25b may be appropriately selected so as to satisfy the above condition. The ratio may be 0.01 to 0.23, 0.02 to 0.15, 0.03 to 0.10, or 0.05 to 0.08, for example.

[0049] A second flow meter 36 is provided in the pipe 26 connected to the connection pipe 27 connected to the second injection port 25a to control the flow rate of the second oxygen-containing gas or the inert gas. The second flow meter 36 measures the flow rate of the second oxygen-containing gas or the inert gas at a predetermined value, for example, when the tip surface area of ​​the second injection port 25b is 1 cm. 2 Any device capable of adjusting the flow rate to 0.1 to 10.0 NL / min per minute can be used, for example, a commercially available mass flow controller. Here, NL / min stands for normal liters per minute, and represents the volume of gas supplied per minute under standard conditions (pressure 0.1013 MPa, temperature 0°C, humidity 0%).

[0050] The connection pipe 27 supplies the second oxygen-containing gas or the inert gas to the second injection part 25a while passing through the upper part of the side wall 2a of the reactor 2. Alternatively, the connection pipe 27 may pass through the upper wall part 2b of the reactor 2 to supply the second oxygen-containing gas or the inert gas to the second injection part 25a.

[0051] Furthermore, in order to equalize the flow rates of the gases, a member covering or burying the first injection part and the second injection part 25a may be further provided in the reactor 2. Specifically, as shown in Fig. 6, in order to equalize the flow rates of the mixed gas used for producing fullerenes and the second oxygen-containing gas or inert gas used for preventing or removing soot-like matter, a cylindrical or approximately cylindrical porous body 28 may be provided on the upstream end side (upper wall part 2b side) of the reactor 2 so as to cover or bury the tip of the first injection part (burner 9) and the tip of the second injection part 25a. The outer diameter of the porous body 28 may be the same as the inner diameter of the furnace 2.

[0052] The thickness of porous body 28 can be selected arbitrarily. For example, in the direction from the upstream end (upper wall portion 2b side) to the downstream end (lower wall portion 2c side), the thickness of porous body 28 from the downstream tips of first injection portion (burner 9) and second injection portion 25a to the lower surface (downstream side) of porous body 28 is preferably 1 to 50 mm, and more preferably 10 to 30 mm. As the porous body, a porous ceramic sintered body, a sintered body of metal powder, or the like that can be used for first injection port portion 23c is preferably used.

[0053] An ignition mechanism 31 for igniting the raw material gas is provided near the exhaust gas outlet 30d of the reactor 2. The position of the ignition mechanism 31 can be selected arbitrarily. In this embodiment, the ignition mechanism 31 is provided outside the exhaust gas outlet 30d of the reactor 2, but it may also be provided inside the furnace.

[0054] In the fullerene production apparatus 1 having the burner 9 and gas introduction section 10 of this embodiment configured as described above, the raw material gas and the first oxygen-containing gas are injected into the reactor 2 from the first injection port 21a of the burner 9 described above (injection I), while the raw material gas is incompletely combusted to generate a soot-like material containing fullerenes in the reactor 2. While the soot-like material is being generated, the second oxygen-containing gas or inert gas is injected into the reactor 2 from the second injection port 22a described above (injection II). Such injection can prevent the generated soot-like material from adhering to the side wall 2a of the reactor 2.

[0055] While fullerenes are produced by injection I, injection II may be carried out, but the timing may be shifted as necessary. For example, in the fullerene production apparatus 1 equipped with the burner 9 and the gas inlet 10 of this embodiment, after the above-mentioned step of producing fullerenes (performing injection I), a second oxygen-containing gas or an inert gas may be injected along the side wall 2a of the reactor 2 (performing injection II). By this method, the soot-like material adhering to the side wall 2a of the reactor 2 can be removed from the side wall 2a.

[0056] As a result, in the fullerene production apparatus 1 equipped with the burner 9 and the gas inlet 10 of this embodiment, it is possible to prevent adhesion of soot-like matter to the side wall 2a of the reactor 2 or to easily remove the adhered soot-like matter, eliminating the need for conventional maintenance work. As a result, it is possible to improve the efficiency of fullerene production.

[0057] (Method of producing fullerene) Next, a method for producing fullerenes using the fullerene production apparatus 1 (the production method of the first embodiment and the production method of the second embodiment) will be described.

[0058] The fullerene production method of the first embodiment includes a fullerene production step in which a hydrocarbon-containing raw material gas is incompletely combusted in the reactor 2 to produce a soot-like substance containing fullerenes. In this step, the raw material gas and a first oxygen-containing gas are injected from a first injection unit disposed on the upstream end (upper wall 2b side) of the reactor 2 from the upstream end (upper wall 2b side) toward the downstream end (lower wall 2c side) of the reactor 2 (injection I), thereby causing incomplete combustion of the raw material gas. While the incomplete combustion is occurring, a second oxygen-containing gas or an inert gas is injected from a second injection unit 25a disposed on the upstream end of the reactor 2 so as to surround the first injection unit along the sidewall 2a of the reactor 2 from the upstream end toward the downstream end of the reactor 2 (injection II). Injection II may be started after injection I, or after injection II, or injection I and injection II may be started simultaneously.

[0059] In the fullerene production method of this embodiment, the soot-like substance is generated by incomplete combustion of the above-mentioned raw material gas and the first oxygen-containing gas. Furthermore, a second oxygen-containing gas or an inert gas is injected along the sidewall 2a of the reactor 2 from the upstream end toward the downstream end of the reactor 2. This injection can prevent the soot-like substance from adhering to the sidewall 2a. It is preferable to inject the second oxygen-containing gas from the viewpoint of reacting with the soot-like substance that has diffused to the sidewall 2a, thereby improving the effect of preventing the soot-like substance from adhering.

[0060] In this case, the flow rate of the second oxygen-containing gas or the inert gas injected from the second injection port portion 25b is set to 1 / cm 2 per 1 cm 2 of the area of ​​the tip surface of the second injection port portion 25b. 2 The flow rate is preferably 0.1 to 10.0 NL / min, more preferably 0.1 to 7.0 NL / min per 1000 ml of the fullerene. Within this range, fullerene can be produced without decreasing the yield.

[0061] Furthermore, in the fullerene production method of this embodiment, after the above-described fullerene production step, a second oxygen-containing gas or an inert gas may be injected along the side wall 2a of the reactor 2 (soot-like matter removal step). For example, in the soot-like matter removal step, the gas supply for injection I and injection II may all be stopped once, and then the gas for injection II may be injected. Alternatively, only the gas supply for injection I may be stopped, while the gas supply for injection II may be continuously injected without being stopped. This makes it possible to remove the soot-like matter adhering to the side wall 2a from the side wall 2a. In this case, the flow rate of the second oxygen-containing gas or inert gas injected from the second injection port portion 25b is set to 1 / 4000 of the flow rate per 1 cm of the tip surface area of ​​the second injection port portion 25b. 2 The flow rate is preferably 0.1 to 10.0 NL / min, more preferably 0.5 to 10.0 NL / min per 1000 mbar. Within this range, the soot-like material adhering to the side wall 2a can be sufficiently removed. Furthermore, it is preferable to inject an inert gas after the step of generating fullerenes, since this does not react with the soot-like material adhering to the side wall 2a and allows the fullerenes in the soot-like material adhering to the side wall 2a to be recovered to the maximum extent.

[0062] The fullerene production method of the second embodiment includes a fullerene production process in which a hydrocarbon-containing source gas and a first oxygen-containing gas are injected from a first injection unit disposed on the upstream end side (upper wall portion 2b side) of the reactor 2 toward the downstream end side (lower wall portion 2c side) while incompletely combusting the source gas to produce a soot-like substance containing fullerenes. The fullerene production process also includes a soot-like substance removal process after the fullerene production process. In the soot-like substance removal process, a second oxygen-containing gas or an inert gas is injected along the sidewall 2a from a second injection unit 25a disposed on the upstream end side of the reactor 2 so as to surround the first injection unit toward the downstream end side to remove the soot-like substance adhering to the sidewall 2a.

[0063] In the fullerene production method of the second embodiment, the soot-like substance removal step is performed before the soot-like substance adhering to the side wall 2a clogs the flow path in the reactor 2. The fullerene production step and the soot-like substance removal step are preferably performed alternately and repeatedly. The number of repetitions can be selected arbitrarily, and may be, for example, 1 to 30 times, 2 to 10 times, or 3 to 6 times. In this case, the flow rate of the second oxygen-containing gas or inert gas injected from the second injection port portion 25b is set to 1 / 2000 of the flow rate per 1 cm of the tip surface area of ​​the second injection port portion 25b. 2 The flow rate is preferably 0.1 to 10.0 NL / min, more preferably 0.5 to 10.0 NL / min per 1000 sq m. Furthermore, it is preferable to inject an inert gas in the soot-like substance removal step, since this does not react with the soot-like substance adhering to the side wall 2a and also maximizes recovery of fullerenes in the soot-like substance adhering to the side wall 2a. In these steps, it is preferable to perform the soot-like substance removal step (injection II) after stopping all gas supplies (injection I) used in the fullerene production step.

[0064] In the fullerene manufacturing methods of the first and second embodiments, the flow rate of the raw material gas supplied to the first injection part may be adjusted by the dimensions of the reactor 2 and the first injection port part 23c. The flow rate of the first oxygen-containing gas is adjusted by the type and flow rate of the raw material gas. The ratio of the number of carbon atoms in the raw material gas supplied to the first injection part per minute to the number of oxygen atoms in the first oxygen-containing gas is preferably 0.60 to 2.00, more preferably 0.60 to 1.60, and even more preferably 0.80 to 1.40. When the ratio is within the above range, the yield of fullerenes is high.

[0065] The pressure inside the reactor 2 can be selected arbitrarily, but is preferably 1 to 30 kPa, and more preferably 1 to 10 kPa. If the pressure inside the reactor 2 is 1 kPa or higher, the load on the pressure reducing mechanism 5 will not be large. On the other hand, if the pressure inside the reactor 2 does not exceed 30 kPa, the flame will not flash back.

[0066] In the step of producing fullerenes, the temperature inside the reactor 2 when incomplete combustion of the raw material gas is carried out can be selected arbitrarily, but is preferably 1000°C to 2000°C, and more preferably 1300°C to 1900°C. When the temperature inside the reactor 2 is 1000°C or higher, a soot-like substance containing fullerenes is efficiently produced, resulting in a good fullerene yield. When the temperature inside the reactor 2 is 2000°C or lower, a large amount of energy is not required to increase the temperature inside the reactor 2, and fullerenes can be produced efficiently. The temperature inside the reactor 2 can be measured using an ultra-high temperature thermocouple or the like.

[0067] Therefore, in the fullerene production method of this embodiment, it is possible to suppress the adhesion of soot-like matter to the side wall 2a of the reactor 2 or to easily remove the adhered soot-like matter, thereby eliminating the need for maintenance work as in the past and improving the efficiency of fullerene production. The duration of the fullerene-producing step and the soot-removing step can be selected arbitrarily. The duration of the fullerene-producing step may be, for example, 60 to 20,000 minutes or 360 to 10,000 minutes. The duration of the soot-removing step may be, for example, 30 to 5,000 minutes or 60 to 1,440 minutes. The manufacturing method of the above embodiment may include a recovery process for recovering the generated soot-like material, a cooling process for cooling the gas from which the soot-like material has been recovered, and a decompression process for reducing the pressure of the cooled gas.

[0068] The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. [Example]

[0069] The effects of the present invention will be made clearer by the following examples. Note that the present invention is not limited to the following examples and can be practiced with appropriate modifications within the scope of the present invention.

[0070] [Calculation of fullerene content] In the following Examples 1 to 7 and Comparative Example 1, the C contained in the recovered soot-like material was measured in accordance with "JIS Z 8981." 60 and C 70 The content (fullerene content) of was measured as follows.

[0071] Specifically, 15 g of 1,2,3,5-tetramethylbenzene (TMB) was added to 0.05 g of the collected soot-like material, and then ultrasonic treatment was performed for 15 minutes to obtain a suspension. The obtained suspension was filtered through a membrane filter with a pore size of 0.5 μm, and the filtrate (sample liquid) was analyzed by high-performance liquid chromatography (HPLC). 60 and C 70 The amount of C contained in the soot was determined. 60 and C 70 The content [mass %] of was calculated.

[0072] Here, C contained in the soot 60 and C 70 When calculating the content of C, it is necessary to measure the content of C in advance. 60 and C 70 A calibration curve prepared using the TMB solution was used.

[0073] The HPLC measurement conditions are as follows. Equipment: Infinity 1260 (Agilent) Sample injection volume: 5 μL Eluent: toluene (47% by volume) / methanol (53% by volume) mixed solvent Eluent flow rate: 1 ml / min Column: YMC-Pack ODS-AM 100*4.6mmID S-3μm, 12nm Measurement temperature: 40℃ Detector: UV 325nm (JIS)

[0074] Example 1 Fullerenes were produced using the fullerene production apparatus 1 shown in Figure 1. The reactor 2 has similar features to the structure shown in Figure 2, unless otherwise specified below. The reactor 2 was made of alumina and had a length of 1000 mm, an inner radius D of 60 mm, and was arranged so that the longitudinal direction was vertical. An alumina layer was provided on the entire outer surface of the reactor 2 as a heat insulating layer.

[0075] A cylindrical porous ceramic sintered body having a length of 60 mm and a radius d3 of 40 mm was used as the first injection port portion 23c of the burner 9. The tip surface of this ceramic sintered body was provided with a first injection port 21a having a diameter of 0.1 mm to 1.5 mm and a substantially circular shape in plan view, the diameter of which was 1 cm. 2 60 to 80 nozzles are formed per nozzle. The radius d3 of the first injection port portion 23c is the inner radius D of the reactor 2, and d3 / D is 0.67.

[0076] 2 and 3, a structure having a second injection part 25a was used as the gas introduction part 10. The tip of the second injection part 25a was located 1 cm upstream of the tip of the first injection port part 23c in the direction from the upper wall part 2b side (upstream end side) to the lower wall part 2c side (downstream end side).

[0077] The second injection part 25a has a cylindrical second injection port part 25b made of a sintered ceramic body and a 2 mm-thick alumina layer (cylindrical inner wall made of alumina) covering the inner peripheral side surface of the second injection port part 25b. That is, the second injection port part 25b is sandwiched between the inner surface of the cylindrical reactor side wall 2a and the cylindrical inner wall. The tip surface (gas ejection part) of the second injection port part 25b is ring-shaped in plan view, with an inner radius of 50 mm and a radial dimension (thickness) d1 of 10 mm.

[0078] The radial dimension (thickness) d1 of the tip surface of the second jetting port portion 25b is such that d1 / D is 0.17, where D is the inner radius of the reactor 2. The radial distance d2 between the outer periphery of the tip surface of the second jetting port portion 25b and the side wall 2a of the reactor 2 is such that d2 / D is 0.00, where D is the inner radius of the reactor 2. In other words, the second jetting port portion 25b directly contacts the side wall 2a. The radial distance d4 between the inner periphery of the tip surface of the second jetting port portion 25b and the first jetting port portion 23c is 10 mm, where D is the inner radius of the reactor 2, and d4 / D is 0.17.

[0079] At the tip end surface of the second injection port portion 25b, the second injection port 22a, which is approximately circular in plan view and has a diameter of 0.1 mm to 1.5 mm, is 1 cm 2 60 to 80 of them are formed per second injection port 25b. The total opening area of ​​the second injection ports 22a relative to the area of ​​the tip end face of the second injection port portion 25b is 87%.

[0080] A camera was installed near the exhaust gas outlet 30d inside the reactor 2, and fullerenes were produced while photographing the inside of the reactor 2 with the camera.

[0081] A mass flow controller (AeraSFC168, manufactured by Hitachi Metals) was used as the flow meter 35a, and mass flow controllers (AeraFC-7810CD, manufactured by Hitachi Metals) were used as the flow meters 35b and 36.

[0082] (Fullerene production process) Toluene as a raw material gas vaporized by a heating device (not shown) was supplied through pipe 24a to the first injection port 23c of burner 9, and oxygen gas (purity 99.9% by volume) as a first oxygen-containing gas was supplied to the reaction furnace 2 through pipe 24b into the burner 9, thereby supplying the gas into the reaction furnace 2 (injection I). The raw material gas was ignited using ignition mechanism 31, and incomplete combustion was caused to initiate the generation of a soot-like substance containing fullerenes. At the same time, air as a second oxygen-containing gas was supplied to gas inlet 10 through pipe 26, thereby supplying the gas into the reaction furnace 2 (injection II).

[0083] In the fullerene production step, the pressure inside the reaction furnace 2 was 5.33 kPa. The flow rate of toluene supplied into the reaction furnace 2 was 38.0 g / min, the flow rate of the first oxygen-containing gas was 26.0 NL / min, and the flow rate of the second oxygen-containing gas was 24.0 NL / min (the area of ​​the tip surface of the second injection port portion 25b was 1 cm). 2 The flow rate of the second oxygen-containing gas was 0.69 NL / min per 1000 kJ / min. Toluene, the first oxygen-containing gas, and the second oxygen-containing gas were successively injected into the reactor 2 from the first injection port 23c and the second injection port 25b of the second injection port 25a, and incomplete combustion was continued for 3 hours. The temperature inside the reactor 2 was 1500°C.

[0084] In Example 1, it was confirmed by the camera that the flame was not extinguished during the fullerene production process of the fullerene production apparatus 1, and that the apparatus operated continuously.

[0085] After that, the operation of the fullerene production apparatus 1 was stopped. After the temperature inside the reactor 2 returned to room temperature, the burner 9 was removed and the condition inside the reactor 2 was visually confirmed. As a result, there was little soot-like matter adhering to the side wall 2a inside the reactor 2, and no clogging of the flow path due to the adhering soot-like matter was observed.

[0086] In addition, the soot-like matter trapped in the collector 12 in Example 1 was recovered. The mass of the recovered soot-like matter was 520 g.

[0087] The content and amount of fullerene in the soot-like substance were determined by the method shown in [Calculation of fullerene content]. As a result, the content of fullerene was 21 mass %, and the amount of fullerene was 109 g.

[0088] Example 2 In Example 2, evaluation was carried out under the same conditions as in Example 1, except as described below. The gas introduction section 10 used had a structure similar to that of the second injection section 25a shown in Figures 4 and 5. The second injection port section 25b was a slit (cylindrical opening) formed between a 3 mm-thick alumina cylinder (inner wall) and the inner surface of the side wall 2a. The tip surface of the second injection port section 25b was ring-shaped (second injection port 22a) in plan view. The inner radius of the tip surface of the second injection port section 25b was 55 mm, and the radial dimension (thickness) d1 was 5 mm.

[0089] The radial dimension (thickness) d1 of the second jetting port portion 25b is such that d1 / D is 0.08, where D is the inner radius of the reactor 2. The radial distance d2 between the outer periphery of the tip surface of the second jetting port portion 25b and the side wall 2a of the reactor 2 is such that d2 / D is 0.00, where D is the inner radius of the reactor 2. The radial distance d4 between the inner periphery of the tip surface of the second jetting port portion 25b and the first jetting port portion 23c is 15 mm, where D is the inner radius of the reactor 2, d4 / D is 0.25.

[0090] The flow rate of the second oxygen-containing gas was set to 24.0 NL / min (the area of ​​the tip surface of the second injection port portion 25b was 1 cm 2 The flow rate of the second oxygen-containing gas was 1.33 NL / min. Other than the above, fullerenes were produced in the same manner as in Example 1.

[0091] In Example 2, the flame was not extinguished in the fullerene production process of the fullerene production apparatus 1, and continuous operation was possible.

[0092] After that, the operation of the fullerene production apparatus 1 was stopped. After the temperature inside the reactor 2 returned to room temperature, the burner 9 was removed and the condition inside the reactor 2 was visually confirmed. As a result, there was little soot-like matter adhering to the side wall 2a inside the reactor 2, and no clogging of the flow path due to the adhering soot-like matter was observed.

[0093] In addition, the soot-like matter trapped in the collector 12 in Example 2 was recovered. The mass of the recovered soot-like matter was 548 g.

[0094] The content and amount of fullerene in the soot-like material were determined in the same manner as in Example 1. As a result, the content of fullerene was 16 mass %, and the amount of fullerene was 88 g.

[0095] Example 3 The flow rate of the second oxygen-containing gas was set to 12.0 NL / min (the area of ​​the tip surface of the second injection port portion 25b was 1 cm 2 Fullerenes were produced in the same manner as in Example 1, except that the flow rate of the second oxygen-containing gas was 0.35 NL / min per 1000 kJ / min.

[0096] In Example 3, the flame was not extinguished in the fullerene production process of the fullerene production apparatus 1, and continuous operation was possible.

[0097] After that, the operation of the fullerene production apparatus 1 was stopped. After the temperature inside the reactor 2 returned to room temperature, the burner 9 was removed and the condition inside the reactor 2 was visually confirmed. As a result, there was little soot-like matter adhering to the side wall 2a inside the reactor 2, and no clogging of the flow path due to the adhering soot-like matter was observed.

[0098] In addition, the soot-like matter trapped in the collector 12 in Example 3 was recovered. The mass of the recovered soot-like matter was 609 g.

[0099] The content and amount of fullerene in the soot-like material were determined in the same manner as in Example 1. As a result, the content of fullerene was 19 mass %, and the amount of fullerene was 116 g.

[0100] Example 4 The second oxygen-containing gas was oxygen gas (purity 99.9% by volume), and the flow rate was 8.0 NL / min (the area of ​​the tip surface of the second injection port portion 25b was 1 cm ). 2 Fullerenes were produced in the same manner as in Example 1, except that the flow rate of the second oxygen-containing gas was 0.23 NL / min per 1000 kJ / min.

[0101] In Example 4, the flame was not extinguished in the fullerene production process of the fullerene production apparatus 1, and continuous operation was possible.

[0102] After that, the operation of the fullerene production apparatus 1 was stopped. After the temperature inside the reactor 2 returned to room temperature, the burner 9 was removed and the condition inside the reactor 2 was visually confirmed. As a result, there was little soot-like matter adhering to the side wall 2a inside the reactor 2, and no clogging of the flow path due to the adhering soot-like matter was observed.

[0103] In addition, the soot-like matter trapped in the collector 12 in Example 4 was recovered. The mass of the soot-like matter recovered was 498 g.

[0104] The content and amount of fullerene in the soot-like material were determined in the same manner as in Example 1. As a result, the content of fullerene was 23 mass %, and the amount of fullerene was 114 g.

[0105] Example 5 The second oxygen-containing gas was nitrogen gas (purity 99.9% by volume), and the flow rate was 24.0 NL / min (the area of ​​the tip surface of the second injection port portion 25b was 1 cm ). 2 Fullerenes were produced in the same manner as in Example 1, except that the flow rate of nitrogen gas was 0.69 NL / min per 1000 kJ.

[0106] In Example 5, the flame was not extinguished in the fullerene production process of the fullerene production apparatus 1, and continuous operation was possible.

[0107] After that, the operation of the fullerene production apparatus 1 was stopped. After the temperature inside the reactor 2 returned to room temperature, the burner 9 was removed and the condition inside the reactor 2 was visually confirmed. As a result, there was little soot-like matter adhering to the side wall 2a inside the reactor 2, and no clogging of the flow path due to the adhering soot-like matter was observed.

[0108] In addition, the soot-like matter trapped in the collector 12 in Example 5 was recovered. The mass of the recovered soot-like matter was 645 g.

[0109] The content and amount of fullerene in the soot-like material were determined in the same manner as in Example 1. As a result, the content of fullerene was 13 mass %, and the amount of fullerene was 84 g.

[0110] Example 6 Fullerenes were produced using the fullerene production apparatus 1 shown in FIG. 6. The cylindrical porous body 28 is disposed from the tip face of the second injection port portion 25b to 30 mm downstream (20 mm downstream from the tip face of the first injection port portion 23c). The radius of the porous body 28 is 60 mm. Other than the above, the structure is the same as that of the fullerene production apparatus 1 used in Example 1. The porous body 28 is made of a ceramic sintered body similar to that of the first injection port portion 23c in Example 1.

[0111] Fullerenes were produced and the fullerene content was measured in the same manner as in Example 1. In Example 6, the flame was not extinguished in the fullerene production step of the fullerene production apparatus 1, and continuous operation was possible.

[0112] After that, the operation of the fullerene production apparatus 1 was stopped. After the temperature inside the reactor 2 returned to room temperature, the burner 9, the gas inlet 10, and the porous body 28 were removed, and the condition inside the reactor 2 was visually confirmed. As a result, there was little soot-like matter adhering to the side wall 2a inside the reactor 2, and no clogging of the flow path due to the adhering soot-like matter was observed.

[0113] In addition, the soot-like matter trapped in the collector 12 in Example 6 was recovered. The mass of the recovered soot-like matter was 532 g.

[0114] The content and amount of fullerene in the soot-like material were determined in the same manner as in Example 1. As a result, the content of fullerene was 23 mass %, and the amount of fullerene was 122 g.

[0115] Example 7 In Example 7, injection I was performed followed by injection II, and this process was repeated multiple times. (Fullerene production process) The same apparatus as in Example 1 was used. Toluene as a raw material gas vaporized by a heating device (not shown) was supplied through pipe 24a to reactor 2 via first nozzle 23c of burner 9, and oxygen gas (purity 99.9% by volume) as a first oxygen-containing gas was supplied to burner 9 through pipe 24b, thereby supplying the gas into reactor 2. The raw material gas was ignited using ignition mechanism 31, causing incomplete combustion and initiating the generation of a soot-like substance containing fullerenes. During these generation processes, gas injection (injection II) from second nozzle 25b was not performed.

[0116] The supply rate of toluene into the reactor 2 was set to 38.0 g / min, the supply rate of the first oxygen-containing gas was set to 26.0 NL / min, and a mixed gas of toluene and oxygen gas was continuously injected into the reactor 2, and incomplete combustion was continued for 30 minutes.

[0117] (Soot removal process) Thereafter, the supply of toluene and the first oxygen-containing gas was stopped. After stopping the supply, the soot-like substance removal process was carried out using the second injection part 25a. Specifically, the flow rate of nitrogen gas as the inert gas was set to 30.0 NL / min (the area of ​​the tip surface of the second injection port part 25b was 1 cm). 2 The active gas was injected into the reactor 2 from the second injection port 25b of the second injection part 25a for 10 seconds.

[0118] The fullerene production process and the soot-like substance removal process were repeated alternately five more times. After this, the operation of the fullerene production apparatus 1 was stopped. After the temperature inside the reactor 2 returned to room temperature, the burner 9 was removed and the condition inside the reactor 2 was visually confirmed. As a result, there was little soot-like substance adhering to the side wall 2a inside the reactor 2, and no clogging of the flow path due to the adhering soot-like substance was observed.

[0119] In addition, the soot-like matter trapped in the collector 12 in Example 7 was recovered. The mass of the recovered soot-like matter was 668 g.

[0120] The content and amount of fullerene in the soot-like material were determined in the same manner as in Example 1. As a result, the content of fullerene was 14 mass %, and the amount of fullerene was 94 g.

[0121] (Comparative Example 1) The fullerene production apparatus used in Comparative Example 1 is the same as the fullerene production apparatus 1 used in Example 1, except that it does not have the gas inlet part 10. In other words, injection II was not performed.

[0122] Toluene as a raw material gas vaporized by a heating device (not shown) was supplied through pipe 24a to the first nozzle 23c of burner 9, and oxygen gas (purity 99.9% by volume) as a first oxygen-containing gas was supplied to the burner 9 through pipe 24b, thereby supplying the gas into the reactor 2. The raw material gas was ignited using ignition mechanism 31, causing incomplete combustion and starting the generation of a soot-like substance containing fullerenes. No gas was supplied through pipe 26. The pressure inside the reactor 2 was 5.33 kPa. The flow rate of toluene supplied to the reactor 2 was 38.0 g / min, and the supply rate of the first oxygen-containing gas was 26.0 NL / min.

[0123] As a result, 45 minutes after the start of the fullerene production process, the backfire prevention device was activated and the fullerene production equipment was shut down.

[0124] In Comparative Example 1, the operation of the fullerene production apparatus was then stopped. After the temperature inside the reactor 2 returned to room temperature, the burner 9 was removed and the condition inside the reactor 2 was visually confirmed. As a result, clogging of the flow path inside the reactor 2 by soot-like matter adhering to the side wall 2a was observed.

[0125] In addition, the soot-like matter trapped in the collector 12 in Comparative Example 1 was recovered. The mass of the recovered soot-like matter was 214 g.

[0126] The content and amount of fullerene in the soot-like material were determined in the same manner as in Example 1. As a result, the content of fullerene was 12 mass %, and the amount of fullerene was 29 g.

[0127] In Examples 1 to 7, no large amount of soot-like matter was observed adhering to the side wall 2a and no clogging of the flow path due to the adhering soot-like matter was observed, compared to Comparative Example 1. It was confirmed that the use of the fullerene production apparatus 1 of the present invention allows for long-term operation and enables fullerenes to be produced efficiently. [Industrial Applicability]

[0128] The present invention can provide a fullerene production apparatus that can improve fullerene production efficiency. [Explanation of symbols]

[0129] 1...Fullerene manufacturing equipment 2...Reactor 2a Reactor side wall 2b Upper wall of reactor 2c Lower wall of reactor 3. Recovery mechanism 4…Cooling mechanism 5...Decompression mechanism (vacuum pump) 6...First pipe 7...Second piping 8...Third piping 9...First injection part (burner) 10...Gas inlet 11...Filter 12...Collector 13...Solenoid valve 14...Tank 15...Discharge valve 16...Drain 21a...First nozzle 22a...Second nozzle 23...Burner holder 23a...Premixing chamber 23b…Accumulation chamber 23c...First nozzle 24a...Plumbing 24b...Plumbing 25a...second injection part 25b...Second nozzle 26...Plumbing 27...Connecting piping 28...Porous material 30d...Exhaust gas outlet 31...Ignition mechanism 35a…Flow meter 35b…Flow meter 36…Flow meter D: Inner radius of reactor d1...Radial thickness d2: Radial distance d3...radius of the injection port d4: Radial distance

Claims

1. a reactor for producing fullerenes by incomplete combustion of a raw material gas containing hydrocarbons; a first injection unit disposed at an upstream end of the reactor and configured to inject the raw material gas and a first oxygen-containing gas toward a downstream end of the reactor while causing incomplete combustion of the raw material gas in the reactor; a second injection unit disposed at the upstream end of the reactor so as to surround the first injection unit, and configured to inject a second oxygen-containing gas or an inert gas toward the downstream end of the reactor along a side wall of the reactor between the upstream end and the downstream end; Equipped with the reactor sidewall is cylindrical; the second injection portion includes a second injection port portion having a ring-shaped tip end surface, The fullerene manufacturing apparatus, wherein d 1 / D is 0.01 to 0.40, where d 1 is the radial thickness of the tip end surface of the second injection port portion and D is the inner radius of the reactor.

2. When the reactor is viewed from a longitudinal cross section in a direction from the upstream end side to the downstream end side, the tip of the second jet is located in the same cross-section of the reactor as the tip of the first jet; or The tip of the second injection part is located upstream of the tip of the first injection part.

2. The fullerene production apparatus according to claim 1 .

3. The radial thickness dimension of the tip surface of the second injection port portion is d １ When the inner radius of the reactor is D, d １ 3. The fullerene producing apparatus according to claim 2, wherein / D is 0.03 to 0.

25.

4. The radial distance between the outer periphery of the tip surface of the second injection port portion and the inside of the side wall of the reactor is d ２ When this is the case, d ２ 2. The fullerene producing apparatus according to claim 1, wherein / D is 0.00 to 0.

10.

5. The first injection part has a cylindrical first injection port part, and a first injection port is provided on the tip surface of the first injection port part. The radius of the first injection port part is d ３ When this is the case, d ３ 2. The fullerene producing apparatus according to claim 1, wherein / D is 0.40 to 0.

96.

6. The radial distance between the outer periphery of the first injection port portion and the inner periphery of the tip surface of the second injection port portion is defined as d ４ When this is the case, d ４ 6. The fullerene producing apparatus according to claim 5, wherein / D is 0.01 to 0.

25.

7. The ring-shaped tip surface of the second injection port portion has a plurality of second injection ports each having a diameter of 0.1 mm to 5.0 mm, the second injection ports are uniformly arranged on the tip surface of the second injection port portion, 2. The fullerene manufacturing apparatus according to claim 1, wherein the ratio of the total opening area of ​​the second injection nozzle to the tip surface area of ​​the second injection nozzle portion is 10% to 95%.

8. 2. The fullerene manufacturing apparatus according to claim 1, wherein the second injection port portion is made of a porous material.

9. 2. The fullerene manufacturing apparatus according to claim 1, wherein the second injection port of the second injection port unit is a ring-shaped slit in a plan view.

10. The flow rate of the second oxygen-containing gas or the inert gas injected from the second injection port is set to 1 / cm2 per tip surface area of ​​the second injection port. ２ 2. The fullerene producing apparatus according to claim 1, wherein the flow rate is 0.1 to 10.0 NL / min per minute.

11. a cylindrical porous body is provided on the upstream end side of the reactor so as to cover or fill the tip of the first injection portion and the tip of the second injection portion; 2. The fullerene production apparatus according to claim 1, wherein the thickness of the porous body from the downstream tip of the first injection part and the second injection part to the downstream end of the cylindrical porous body is 1 to 50 mm in the direction from the upstream end to the downstream end.

12. A method for producing fullerenes using the fullerene production apparatus according to any one of claims 1 to 11, a fullerene production step of producing a soot-like substance containing fullerenes in a reactor by incomplete combustion of a raw material gas containing hydrocarbons, In the fullerene production step, the raw material gas and a first oxygen-containing gas are injected from a first injection unit disposed on the upstream end side of the reactor toward a downstream end side of the reactor, while the raw material gas is incompletely combusted in the reactor, and A method for producing fullerenes, comprising injecting a second oxygen-containing gas or an inert gas from a second injection section disposed on the upstream end side so as to surround the first injection section toward the downstream end side along a side wall of a reactor located between the upstream end side and the downstream end side.

13. A method for producing fullerenes using the fullerene production apparatus according to any one of claims 1 to 11, a fullerene production step in which a hydrocarbon-containing raw material gas and a first oxygen-containing gas are injected from a first injection unit disposed on the upstream end side of the reactor toward the downstream end side, while the raw material gas is incompletely combusted to produce a soot-like substance containing fullerenes; A method for producing fullerenes, comprising a soot-like matter removal step of, after the fullerene production step, injecting a second oxygen-containing gas or an inert gas from a second injection part, which is arranged so as to surround the first injection part on the upstream end side of the reactor, toward the downstream end side along a side wall of the reactor between the upstream end side and the downstream end side, thereby removing the soot-like matter adhering to the side wall of the reactor.

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