JP2010012422A - Fluidized bed reactor and manufacturing method of vapor grown carbon fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluidized bed reactor dispensing with a diffusion plate, or allowing installation of the diffusion plate at a low temperature part outside a heating region, and eliminating clogging and deterioration of the diffusion plate conventionally preventing a long term operation, and a manufacturing method of vapor grown carbon fiber providing a large amount of vapor grown carbon fiber inexpensively. <P>SOLUTION: The fluidized bed reactor has a fluidized part wherein particles fluidize together with gas to cause a contact reaction for forming a solid product, and a non-fluidized part substantially not fluidizing. The fluidized part is in the heating region, and a support part of the non-fluidized part is located outside the heating region. The manufacturing method of the vapor grown carbon fiber uses the reactor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluidized bed reactor used for a chemical reaction, and more particularly to a fluidized bed reactor capable of continuous operation without being stopped due to clogging or deterioration of a dispersion plate. The present invention also relates to a method for producing vapor grown carbon fiber using the fluidized bed reactor.

  In general, apparatuses for performing a reaction operation of a gas and a solid, or a liquid and a solid, or a physical operation are roughly classified into a batch reaction apparatus, a fixed bed type reaction apparatus, a moving bed reaction apparatus including a rotary furnace, a gas bed reaction apparatus, Examples thereof include a fluidized bed reactor. These reaction apparatuses are variously selected depending on the reaction raw materials and reaction forms. In particular, when a product is obtained from a gaseous raw material using a solid catalyst, a fluidized bed reactor capable of realizing a complete mixed flow with high contact efficiency between the raw material and the catalyst is suitable.

An example of a general fluidized bed reactor is shown in FIG. The fluidized bed reactor 30 includes a reactor 31 and a heater 32. A dispersion plate 33 for dispersing the rising gas is provided below the reactor 31. On the dispersion plate 33, a fluidizing part 34 through which catalyst particles and reaction products flow is provided.
The raw material gas flows from the lower part to the upper part of the reactor 31 through the pipe 35. The catalyst particles constituting the fluidizing part 34 are brought into a fluidized state by the flow of the raw material gas while being held by the dispersion plate 33 installed in the heating region formed by the heater 32. When a solid product is produced by contact between the source gas and the catalyst particles in the heating zone, the product is fluidized in a mixed state with the catalyst particles or is discharged out of the system along with the gas flow. The The product staying in the system is discharged from the reaction system by some discharging means after the predetermined time or continuously.

  Here, in general, the behavior of a solid (catalyst particles) in a gas is determined by the gas linear velocity, gas density, viscosity, solid density, particle size, and the like. For example, if the fluidization start speed is Ufm and the end speed is Uc, the solid will flow in the gas if the actual gas linear velocity (u) is Ufm <u <Uc. It does not flow when u <Ufm. Further, when u> Uc, the solid is accompanied by the gas flow and discharged out of the system. Therefore, in the fluidized bed reactor, the gas flow rate, the solid particle diameter, and the like are adjusted so that Ufm <u <Uc.

  In the past, such fluidized bed reactors, such as petroleum gas-phase fluid catalytic cracking, fluidized bed hydroforming for reforming low octane naphtha, fluid coking to obtain light oil from heavy oil, naphtha It is applied to various reactions in the petrochemical industry such as ethylene and propylene production by fluid pyrolysis.

  Furthermore, as a fluidized bed combustion boiler, a fluidized bed incinerator as a waste incinerator, and a catalytic reactor using a fluidized bed, in addition to the gas phase polymerization of acrylonitrile, maleic anhydride, olefin, etc. There are also many examples of research on the synthesis of carbon nanotubes using styrene.

In Patent Document 1, as a gasification device for an organic substance, by providing a tapered portion in a part of the device, a solid residue is retained at the bottom while the catalyst component is retained at the tapered portion, and the generated gas is recovered. A method is disclosed. Patent Document 2 discloses the use of a fluidized bed reactor for the synthesis of carbon nanotubes and the like.
JP 2006-334535 A JP 2008-56523 A

  In the case of obtaining a gaseous product as in Patent Document 1, since the production of a solid substance is not significant, problems such as clogging of the dispersion plate are not significant. When the product is a solid, various attempts have been made to efficiently recover the product while maintaining a fluid state. However, due to clogging of the dispersion plate and deterioration of the dispersion plate, continuous operation for a long time is difficult, and it is necessary to periodically stop the reactor and replace the dispersion plate, which is not efficient. In particular, there are cases where a reaction at a high temperature is required, and it is difficult to select a durable dispersion plate material due to the corrosiveness and reactivity to the reaction gas. In such a case, even if a dispersion plate having relatively excellent durability is used, periodic replacement is unavoidable.

  In the example of Patent Document 2, a quartz sintered plate is used as the dispersion plate. However, it is known that the quartz sintered plate is likely to be blocked by long-term use. Further, when scaled up for industrial use, it is difficult to increase the size of the quartz sintered plate, and a metal material must be used. In the synthesis of carbon nanotubes, when a metal material is used for the dispersion plate, carbon nanotubes are generated on the surface of the metal material due to its catalytic action, and clogging of the dispersion plate becomes remarkable. Not in.

  The present invention has been made in view of the above circumstances. That is, according to the present invention, it is not necessary to use a dispersion plate, or it is possible to install the dispersion plate in a low-temperature part outside the heating region, which has been a hindrance to long-term continuous operation. An object of the present invention is to provide a fluidized bed reactor capable of eliminating clogging and deterioration. The present invention also provides a method for producing vapor-grown carbon fiber that can obtain a large amount of vapor-grown carbon fiber at low cost by using the production apparatus for producing vapor-grown carbon fiber. .

  As a result of intensive studies to achieve the above object, the present inventors have found that the heated region heated to the reaction temperature is substantially equal to the region where the filler material is in a fluid state during the reaction (fluid portion) and the filler material is substantially By dividing it into a non-flowing area (non-flowing part) and providing a support part for the non-flowing part outside the heating area, there is no need for a dispersion plate, or even when a dispersion plate is used The present inventors have found that it is no longer necessary to stop the reaction due to deterioration or deterioration, and that a continuous reaction can be performed for a long time.

That is, the present invention includes the following.
[1] It has a fluidized part in which particles flow together with a gas and undergoes a contact reaction to produce a solid product, and a non-fluidized part that does not substantially flow, the fluidized part is in a heating region, This is a fluidized bed reactor in which the support part of the fluidized part is outside the heating region.
[2] The fluidized bed reactor according to [1], wherein the support part of the non-fluid part is a dispersion plate.
[3] The fluidized bed reactor according to [1] or [2], wherein the non-fluid part includes the solid product.
[4] The non-fluid part and the fluid part are formed in the heating region by increasing the gas linear velocity due to a temperature difference from the outside of the heating region to the inside of the heating region. A fluidized bed reactor according to any one of the above.
[5] The fluidized bed reactor according to any one of [1] to [4], wherein the maximum cross-sectional area of the reactor in the fluidized section is equal to or less than the minimum cross-sectional area of the reactor in the non-fluidized section in the heating region. It is.
[6] The fluidized bed reaction apparatus according to any one of [1] to [4], wherein the diameter of the reactor in the non-fluidized part decreases continuously or intermittently toward the fluidized part.
[7] The fluidized bed reactor according to any one of [1] to [6], having a product recovery mechanism.
[8] The fluidized bed reactor according to any one of [1] to [7], which has a catalyst charging mechanism.

[9] The fluidized bed reaction apparatus according to any one of [1] to [8], wherein the particles and the gas are brought into contact with each other in the fluidized part.
[10] The method for producing vapor grown carbon fiber according to [9], wherein the temperature of the heating region is 400 to 1300 ° C.
[11] The method for producing vapor grown carbon fiber according to [9] or [10], wherein the particle is a catalyst containing Fe element, and the fluidized portion contains vapor grown carbon fiber.
[12] The gas linear velocity is increased by a temperature difference from the outside of the heating region to the inside of the heating region, and a non-flow portion and a fluid portion are formed in the heating region. It is a manufacturing method of vapor phase method carbon fiber.
[13] By setting the maximum cross-sectional area of the reactor in the flow section to be equal to or less than the minimum cross-sectional area of the reactor in the non-flow section in the heating region, the gas linear velocity is changed to change the non-flow section and the flow A vapor grown carbon fiber production method according to any one of [9] to [11].
[14] The method for producing a vapor grown carbon fiber according to any one of [9] to [13], wherein the vapor grown carbon fiber is recovered from the fluidized part after reacting for a predetermined time by a batch reaction.
[15] The gas phase method according to any one of [9] to [14], wherein the vapor phase carbon fiber is continuously or intermittently recovered from the fluidized part while the particles are continuously or intermittently charged. It is a manufacturing method of carbon fiber.

  According to the fluidized bed reactor of the present invention, it is not necessary to use a dispersion plate, or it is possible to install the dispersion plate in a low temperature part outside the heating region, which has conventionally hindered long-term continuous operation. It is possible to eliminate clogging and deterioration of the dispersion plate. Moreover, according to the method for producing vapor grown carbon fiber of the present invention, a large amount of vapor grown carbon fiber can be produced at low cost.

[Fluidized bed reactor]
FIG. 1 shows an example of a preferred embodiment of the fluidized bed reactor according to the present invention.
The fluidized bed reactor 10 includes a reactor 11 and a heater 12 provided on the outer periphery of the reactor 11. By the heat treatment by the heater 12, a heating region (a region in which a heating unit such as the heater 12 is provided) is formed in the reactor 11. A non-fluid part 13 and a fluid part 14 are formed in the reactor 11 during the reaction. The filling material constituting the non-fluid portion 13 is fixed to such an extent that it does not substantially flow, that is, does not flow or vibrates at all depending on the gas supplied from below to above through the pipe 15. Moreover, the fluidized part 14 is comprised with particle | grains etc., flows with the gas supplied, and produces | generates a solid-state product through a contact reaction with source gas.

  As shown in FIG. 1, the flow portion 14 is in the heating region, and the support portion (lower end portion) of the non-flow portion 13 is outside the heating region. According to such a configuration, since the support portion of the non-fluid portion 13 is outside the heating region, the influence of the received heat can be made much smaller than when the dispersion plate is provided in the heating region as in the prior art. As a result, it is possible to eliminate clogging and deterioration of the dispersion plate, which has been an obstacle to long-term continuous operation.

In order to prevent the non-fluid portion 13 from substantially flowing due to the supplied gas, the density and particle diameter of the filling material are adjusted as appropriate. When the filling material is a particulate substance, it is most preferable that the particulate substance contains a solid product (reaction product) from the viewpoint of suppressing contamination. Further, it is preferable that the filling material in the non-flowing portion has a small gap between the materials because the flowing portion is less likely to be mixed into the non-flowing portion due to gas flow disturbance or the like. Therefore, the filling material in the non-fluid part is preferably about the same size as the particles in the fluid part, and more preferably at least part of it is the same.
In addition, it is not preferable that the particulate matter contains catalyst particles because the reaction proceeds in the non-fluid part.

  The non-flow part 13 exists even outside the heating region as shown in FIG. The support part of the non-fluid part 13 can be held by any kind of dispersion plate 16 as used in a general fluidized bed reactor. Examples of the dispersion plate include a gas dispersion plate in which predetermined holes are formed and gas is dispersed. By disposing the dispersion plate outside the heating region, continuous operation can be performed without suffering from adverse effects such as deterioration due to heat, side reactions, and clogging due to reaction products.

  About the method of hold | maintaining the support part of the non-fluid part 13, if it is a structure which can hold | maintain the weight other than using the above-mentioned dispersion plate, it will not specifically limit. A simple bottom plate may be used, and for example, it can be held by a discharge device such as a table feeder or a screw feeder. In this case, it is preferable that the raw material gas is blown from a side surface of the non-flow portion 13 of the reactor 11 by installing a nozzle or the like.

  In order for the fluidizing section 14 to be fluidized by the supplied gas, it is filled with particles having a density and particle diameter that can be fluidized. At least one of the particles is preferably a catalyst particle, and the other one is more preferably a particle made of a solid product, and is composed only of particles made of a catalyst particle and a solid product. Is most preferred.

  The method of providing the non-fluid part 13 and the fluid part 14 is not particularly limited. If the gas linear velocity of the non-fluid portion 13 is set to be equal to or lower than the fluidization start speed of the filling material of the non-fluid portion 13, and the gas linear velocity of the fluid portion 14 is set to be equal to or higher than the fluidization start speed of the particles of the fluid portion 14 and equal to or lower than the terminal velocity. Good. Preferred examples of providing such a non-fluid part 13 and a fluid part 14 are given in the following (1) to (4).

(1) First Example The first example is a method that utilizes the temperature distribution in the heating region. The raw material gas introduced from below the reactor rises in temperature by passing through the heating region and reaches the reaction temperature. At this time, since the volume of the gas expands, the gas flow rate increases as the temperature rises. Therefore, when a reactor is filled with a packing material (for example, powder) having an appropriate density and particle size, fluidization starts from a region having a heating zone, and a fluidized portion and a non-fluidized portion are formed. be able to. By selecting the gas flow rate, the density of the granular material, and the particle diameter in accordance with the reaction temperature, the fluidized part and the non-fluidized part can be installed at desired positions. The raw material gas used for the reaction is often preheated. In this case, however, the preheating and other treatments are not performed, and the difference in gas linear velocity is larger when the gas temperature difference between the reactor inlet temperature and the fluidized part temperature is larger. Since it becomes large, it may be preferable.

(2) Second Example In the second example, the maximum cross-sectional area of the reactor of the fluidized part (where the fluidized part is formed) is the reactor of the non-fluidized part in the heating region (the non-fluidized part is formed). A method of adjusting the gas flow rate to be equal to or less than the minimum cross-sectional area of the portion). Thereby, the cross-sectional area of the fluidized part becomes equal to or smaller than the cross-sectional area of the non-fluidized part. And since the gas flow rate becomes large in the fluidized part, the diameter of the non-fluidized part is determined so that the gas linear velocity is less than or equal to the fluidization start speed in the non-fluidized part. What is necessary is just to determine so that it may become below terminal speed. Therefore, it is preferable to have a structure in which the reactor diameter is large in the non-flow portion and smaller than the flow portion in the heating region.

As the above structure, for example, as shown in FIG. 1, the cross-sectional area of the reactor in the non-flow portion may continuously decrease toward the flow portion (taper shape). It is good also as a staircase shape that an area reduces intermittently. The staircase shape that decreases intermittently refers to a shape having a step at the boundary between the non-flow portion 23 and the flow portion 24 as shown in FIG.
In the first example described above, restrictions such as the gas flow rate and selection of the granular material increase, so the second example is more preferable.

(3) Third Example The third example is the flow of the non-fluid part even if the gas linear velocity is constant by changing the density and particle diameter of the powder particles filling the non-fluid part and the fluid part. A non-fluid part and a fluid part are formed by making the fluidization start speed larger than the fluidization start speed of the fluid part.

  In addition, when the granular material with which a non-fluid part and a fluid part are filled is not a solid product, there is a possibility that the granular material is mixed into the product (solid product). Therefore, it is preferable to use the solid product as a granule that is filled in each of the non-fluid part and the fluid part by adjusting the particle diameter and density by granulating and compacting the product.

(4) Fourth Example In the fourth example, the raw material gas or fluidized gas is introduced from the lower part of the non-fluidized part at a linear velocity equal to or lower than the fluidization start speed of the non-fluidized part, and further fluidization is started in the fluidized part. The reaction gas or fluidizing gas is introduced through a nozzle or the like so as to be higher than the speed. In this example, the gas flow is disturbed in the vicinity of the gas introduction part, and the boundary between the fluid part and the non-fluid part may be disturbed. In such a case, the flow rate of the fluidizing gas is adjusted, Adjust the position and number.

If the fluidized bed reactor of the present invention has a fluidized part and a non-fluidized part, and the support part of the non-fluidized part is outside the heating region, various elemental techniques used in general fluidized bed reactors are used. It is naturally possible to use it. As an example of such a technique, it is of course possible to recirculate the fine particle part by installing a free board part or a cyclone in the upper part of the reactor.
In addition, after reacting for a predetermined time in a batch reaction, a catalyst is supplied intermittently or continuously into a product recovery mechanism for recovering a solid product (such as vapor-grown carbon fiber) from a fluidized part or a reactor. A catalyst charging mechanism may be provided.

  In the fluidized bed reactor of the present invention, as shown in FIGS. 1 and 2, the raw material gas is preferably circulated from the lower part to the upper part of the reactor. As described above, it is naturally possible to introduce part or all of the raw material gas into the fluidizing section. When the raw material for the reaction is solid or liquid, it is preferably used as a raw material gas after vaporizing it in advance.

  In the fluidized bed reactor of the present invention, a fluidizing gas can be used in combination with the above raw material gas in order to adjust the gas linear velocity. The fluidizing gas is not particularly limited as long as it does not adversely affect the reaction, and any kind of gas can be used.

In addition, the fluidized bed reaction apparatus of the present invention can be applied to any reaction as long as the reaction is performed in a fluidized state in the fluidizing section.
However, problems such as clogging of the dispersion plate are unlikely to occur without using the present invention when the production of solids is small, such as when the product is a gaseous substance. Therefore, the reaction product is preferably a solid, and more preferably used for the production of vapor grown carbon fiber.

[Method of producing vapor grown carbon fiber]
The method for producing vapor-grown carbon fiber of the present invention is such that particles and gas are brought into contact with each other in a fluidized part in the fluidized bed reactor of the present invention described above. Also in the present invention, it is preferable that the gas linear velocity is increased (changed) by the temperature difference from the outside of the heating region to the inside of the heating region in the fluidized bed reactor so that the non-fluid part and the fluid part are formed in the heating area. The above-described first to fourth examples can be applied to the forming method of the non-fluid part and the fluid part. Further, the contact between the particles and the gas is preferably carried out under conditions of vapor grown carbon fiber formation with the temperature of the heating region being 400 to 1300 ° C. Furthermore, the temperature of the support part of the non-flowing part is not particularly limited as long as the dispersion plate used for the support part and the raw material gas do not react or deteriorate. Since the preferred temperature range varies depending on the material and shape of the dispersion plate used, the type concentration of the raw material gas, etc., it cannot be generally determined, but is usually 300 ° C. or lower, preferably 200 ° C. or lower, more preferably 100 ° C. or lower. is there.

  The gas linear velocity in the non-fluid part is preferably 0.1 m / sec or less, more preferably 0.05 m / sec or less, and further preferably 0.02 m / sec or less. Further, the gas linear velocity in the fluidized portion is preferably 0.05 m / sec or more, more preferably 0.10 m / sec or more, and further preferably 0.15 m / sec or more.

  Here, the fluidization range of the reaction product (fluidization start speed to termination speed) is preferably at least partially the same as the fluidization range of the catalyst. If the terminal rate of the reaction product is smaller than the terminal rate of the catalyst, the product generated during the reaction can be discharged continuously, which may be more preferable, but this does not allow sufficient residence time. In this case, it is preferable that the termination rate of the reaction product is equal to the termination rate of the catalyst.

  The particles are preferably a catalyst containing Fe element, and the fluidized part preferably contains vapor grown carbon fiber.

The catalyst is not particularly limited as long as it promotes the formation of vapor grown carbon fiber, but generally contains a transition metal element such as Fe, Co, Ni, etc., and contains an Fe element. More preferably. Furthermore, a supported catalyst having the above metal supported on a carrier is preferable.
Moreover, it is preferable to contain other transition metal elements as a promoter. As such a promoter element, Mo, W, Cr, V, Mn, Ti and the like are preferable, and combinations of two or more such as Mo and V, Mo and Cr, W and V, and W and Cr are more preferable.

  These catalysts can be used as precursor particles, metal or alloy particles, but are preferably supported on a carrier. As the catalyst carrier, any known compound can be used, but an inorganic substance that is stable under the reaction conditions is preferable. Examples of such a preferable inorganic carrier include alumina, silica, titania, silica titania, magnesia, spinel and the like.

  Since it is desirable that the catalyst particles and the supported catalyst particles are in a fluid state under the reaction conditions, the particle diameter is preferably 1 to 1000 μm, more preferably 10 to 500 μm. The particle size of the catalyst particles and the supported catalyst particles can be adjusted to a preferred range by appropriately adjusting the catalyst adjustment conditions and the catalyst precursor compound and catalyst carrier used for catalyst adjustment. It is particularly preferable to adjust to a desired particle size range by pulverizing, crushing, and classifying.

  The above gas as a raw material can be any carbon compound that can be used for the synthesis of vapor grown carbon fiber such as methane, ethane, ethylene, propylene, benzene, toluene, and those diluted with a carrier gas. It can be used as a reaction gas.

  In the non-flow portion, it is preferable to use vapor grown carbon fiber itself as a filling material. Although it is possible to configure the fluidized part only with the supported catalyst, in the synthesis of vapor grown carbon fiber, since the volume expansion during synthesis is large, the fluidized part should also contain vapor grown carbon fiber. It is preferable because volume expansion can be relaxed and the reactor is hardly blocked.

  The supported catalyst can be filled in the reactor at the same time as the vapor grown carbon fiber filled in the fluidized part in advance, but a catalyst charging mechanism is installed in the reactor to supply the catalyst intermittently or continuously. It is also possible.

  Solid products (such as vapor grown carbon fibers) can be recovered after a predetermined reaction time. In this case, only the fluidized part may be recovered, or the fluidized part and the non-fluidized part may be recovered simultaneously. Since the fluidized part may be mixed with the non-fluidized part due to turbulence of the gas flow during the reaction, it is more preferable to collect the part including the non-fluidized part.

  It is also possible to recover the product continuously during the reaction. In this case, since the volume expands as the reaction proceeds, it is more preferable to continuously recover the solid product so that the powder height in the reactor becomes constant.

  Since the vapor grown carbon fiber obtained by the production method of the present invention is efficiently contacted with particles (for example, catalyst) and gas (for example, raw material gas), the vapor grown carbon fiber per unit catalyst (for example, A large amount of carbon nanotubes is generated. Furthermore, since the contamination is suppressed by using the vapor grown carbon fiber as a powder body that fills the fluidized portion and the non-fluidized portion, it has a feature that a high purity vapor grown carbon fiber is easily obtained. . The amount of metal impurities in the vapor grown carbon fiber obtained in the present invention is usually 10% by weight or less, preferably 5% by weight or less, more preferably 3% by weight or less, and most preferably 1.5% by weight or less. .

  The present invention will be described in more detail below with typical examples. Note that the present invention is not limited to these.

(Preparation of supported catalyst)
1.8 parts by mass of iron (III) nitrate nonahydrate (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 1.5 parts by mass of methanol. Next, 0.05 parts by mass of ammonium metavanadate (special grade reagent manufactured by Kanto Chemical) and 0.075 parts by mass of ammonium heptamolybdate (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) were dissolved to obtain a catalyst preparation solution. The catalyst preparation liquid was dropped and kneaded into 1 part by mass of commercially available gamma alumina (AKP-G015 manufactured by Sumitomo Chemical Co., Ltd.) to obtain a paste-like mixture. The paste-like mixture was dried with a vacuum dryer at 100 ° C. for 4 hours, pulverized with a mortar and classified to 45 μm to 250 μm to prepare a catalyst.

(Comparative Example 1)
Using the fluidized bed reactor shown in FIG. 4, vapor grown carbon fiber was produced as follows.
First, a 30 mmφ quartz reaction tube (length 110 cm) is used as the reactor 41, and a stainless steel 325 mesh net is positioned as the dispersion plate 43 at the center of the electric furnace (height 40 cm) as the heater 42. It was installed in the reaction tube. A portion of the reaction tube covered with the heating portion of the electric furnace forms a heating region by heating (the same applies to Example 1). On the dispersion plate 43, 10 g of vapor grown carbon fiber and 0.5 g of catalyst were filled and a fluidized portion 44 was provided.

In this state, the electric furnace was heated to 690 ° C. while flowing nitrogen gas adjusted to 1500 ml / min by the mass flow controller 45a. Thereafter, the supply of nitrogen gas was stopped, and ethylene gas and hydrogen gas adjusted to 900 ml / min were circulated by the mass flow controllers 45b and 45c, respectively, and the reaction was performed for 60 minutes. A good flow state was shown during the reaction. The fluidized part height at that time was 20 cm. After completion of the reaction, the reaction gas was switched to 1500 ml / min of nitrogen gas, the reaction furnace was cooled, and vapor grown carbon fiber was recovered. The recovered amount of vapor grown carbon fiber was 22 g.
It was 1.8 mass% when the metal impurity amount of the collect | recovered vapor grown carbon fiber was measured as follows. In addition, a large amount of vapor grown carbon fiber adhered to the dispersion plate after the reaction. When the dispersion plate was taken out and bent by hand, it was easily broken, so it was found that Comparative Example 1 was not suitable for long-term continuous operation.

  The amount of impurities was measured using a CCD multi-element simultaneous ICP emission spectroscopic analyzer (manufactured by VARIAN: VISTA-PRO) with a high-frequency output of 1200 W and a measurement time of 5 seconds. Specifically, 0.1 g of vapor grown carbon fiber was precisely weighed in a quartz beaker and subjected to sulfur nitrate decomposition. After cooling, the volume was adjusted to 50 ml. This solution was appropriately diluted, and each element was quantified by ICP-AES (Atomic Emission Spectrometer).

Example 1
Using the fluidized bed reactor shown in FIG. 2, vapor grown carbon fiber was produced as follows.
First, as the reactor 21, a quartz reaction tube (length 40 cm) having a diameter of 30 mmφ and a quartz reaction tube (length 70 cm) having a diameter of 50 mmφ were used. The quartz reaction tube side with a diameter of 50 mmφ is the non-flow portion 23, the quartz reaction tube side with a diameter of 30 mmφ is the flow portion 24, and the boundary between the non-flow portion and the flow portion is set at the center of the heater 22 (height 40 cm). A stainless steel 325 mesh net was installed as a dispersion plate 26 at a portion 15 cm from the lower end of the heater 22. The non-fluid part was filled with 100 g of the vapor grown carbon fiber prepared in Comparative Example 1, and the fluidized part was filled with 2.5 g of the vapor grown carbon fiber and 0.5 g of the supported catalyst.

  In this state, the electric furnace was heated to 690 ° C. while flowing nitrogen gas adjusted to 1500 ml / min by the mass flow controller 25a. Thereafter, the supply of nitrogen gas was stopped, and the reaction was carried out by flowing ethylene gas and hydrogen gas adjusted to 900 ml / min with the mass flow controllers 25b and 25c, respectively. The temperature of the dispersion plate 26 was about 45 ° C.

Although no powder flow was confirmed in the non-fluid part, the vapor grown carbon fiber and the catalyst were vigorously flowing in the fluid part. When the reaction was carried out for 60 minutes as it was, the height of the fluidized part was about 20 cm, and it flowed violently from the boundary with the non-fluidized part. After the reaction, the reaction gas was switched to 1500 ml / min of nitrogen gas, the reaction furnace was cooled, and vapor grown carbon fiber was recovered. The recovered vapor grown carbon fiber was 120 g. The amount of metal impurities in the recovered vapor grown carbon fiber was measured in the same manner as in Comparative Example 1, and the amount of metal impurities in the vapor grown carbon fiber produced in this reaction from the amount of impurities in the initially introduced vapor grown carbon fiber. Was calculated to be 1.2% by mass in total.
It was found that there was no adhesion of vapor grown carbon fiber on the dispersion plate after the reaction, and there was no damage even if it was bent by hand, and long-term continuous operation was possible.

It is a schematic block diagram which shows the one aspect | mode of the fluidized bed reaction apparatus of this invention. It is a schematic block diagram which shows the one aspect | mode of the fluidized bed reaction apparatus of this invention. It is a schematic block diagram which shows the one aspect | mode of the conventional fluidized bed reaction apparatus. It is a schematic block diagram which shows the fluidized bed reaction apparatus used by the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,20 ... Fluidized bed reactor 11,21 ... Reactor 12,22 ... Heater 13,23 ... Non-flow part 14,24 ... Flow part 15,25 ... Pipe 16 , 26 ... Support plate

Claims (15)

The particles flow together with the gas to contact and react to form a solid product, and a non-flowing portion that does not substantially flow,
The fluidized bed reaction apparatus, wherein the fluidized part is in a heating region, and the support part of the non-fluidized part is outside the heating region.   The fluidized bed reactor according to claim 1, wherein the support part of the non-fluid part is a dispersion plate.   The fluidized bed reaction apparatus according to claim 1 or 2, wherein the non-fluid part includes the solid product.   The non-fluid part and the fluid part are formed in the heating region by increasing the gas linear velocity due to a temperature difference from the outside of the heating region to the inside of the heating region. The fluidized bed reactor described.   The fluidized bed reactor according to any one of claims 1 to 4, wherein a maximum cross-sectional area of the reactor in the fluidized part is equal to or less than a minimum cross-sectional area of the reactor in the non-fluidized part in the heating region.   The fluidized bed reaction apparatus according to any one of claims 1 to 4, wherein the diameter of the reactor in the non-fluid part decreases continuously or intermittently toward the fluid part.   The fluidized bed reactor according to any one of claims 1 to 6, which has a product recovery mechanism.   The fluidized bed reactor according to any one of claims 1 to 7, which has a catalyst charging mechanism.   The manufacturing method of the vapor grown carbon fiber which makes the said particle | grains and the said gas contact in the fluidized part in the fluidized bed reaction apparatus of any one of Claims 1-8.   The method for producing vapor grown carbon fiber according to claim 9, wherein the temperature of the heating region is 400 to 1300 ° C.   The method for producing vapor grown carbon fiber according to claim 9 or 10, wherein the particles are a catalyst containing Fe element, and the fluidized portion contains vapor grown carbon fiber.   The gas phase according to any one of claims 9 to 11, wherein a gas linear velocity is increased by a temperature difference from the outside of the heating region to the inside of the heating region to form a non-fluid part and a fluid part in the heating region. A method for producing carbon fiber.   By making the maximum cross-sectional area of the reactor of the fluidized part not more than the minimum cross-sectional area of the reactor of the non-fluidized part in the heating region, the gas linear velocity is changed and the non-fluidized part and the fluidized part are The method for producing vapor grown carbon fiber according to any one of claims 9 to 11, which is formed.   The method for producing vapor grown carbon fiber according to any one of claims 9 to 13, wherein the vapor grown carbon fiber is recovered from the fluidized part after reacting for a predetermined time in a batch reaction.   The vapor grown carbon fiber according to any one of claims 9 to 14, wherein the vapor grown carbon fiber is continuously or intermittently recovered from the fluidized part while the particles are continuously or intermittently charged. Production method.

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