KR20140146730A - Fluidized bed reactor and process for manufacturing carbon nanostructures using same - Google Patents

Abstract

In the present invention, provided is a fluidized bed reactor, comprising a main body of reactor in which a reaction space is formed; a dispersion plate which is installed in the main body of the reactor; and a hole plate with plurality of holes whose outer circumference is installed to be separated from the inner wall of the main body of the reactor by dividing the upper reaction space of the dispersion plate into an upper part and a lower part, and a manufacturing method of carbon nanostructures using the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed reactor and a carbon nanostructure using the fluidized bed reactor,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed reactor, and more particularly, to a fluidized bed reactor that can be used for producing carbon nanostructures such as carbon nanotubes.

Fluidized bed reactors are reactor devices that can be used to perform a variety of multiphase chemical reactions. In a fluidized bed reactor, a fluid (gas or liquid) reacts with a solid material in a particulate state, typically the solid material is a catalyst having the shape of a small sphere and the fluid is flowed at a rate sufficient to float the solid material So that the solid material behaves like a fluid.

On the other hand, carbon nanostructures (CNS) refer to nano-sized carbon structures having various shapes such as nanotubes, nanofibers, fullerenes, nanocons, nanohorns, and nano-rods and have various excellent properties It is highly utilized in various technical fields. Carbon nanotubes (CNTs), which are typical carbon nanostructures, are formed by bonding three neighboring carbon atoms to each other in a hexagonal honeycomb structure to form a carbon plane, and the carbon plane is cylindrically shaped to have a tube shape. Carbon nanotubes have a characteristic of being a conductor or a semiconductor according to the structure, that is, the diameter of a tube, and can be widely applied in various technical fields, and thus, they are popular as new materials. For example, the carbon nanotube can be applied to an electrode of an electrochemical storage device such as a secondary cell, a fuel cell or a supercapacity, an electromagnetic wave shielding, a field emission display, or a gas sensor.

The carbon nanostructure can be produced by, for example, an arc discharge method, a laser evaporation method, or a chemical vapor deposition method. In the chemical vapor deposition method among the above-described manufacturing methods, carbon nanostructures are produced by dispersing and reacting metal catalyst particles and hydrocarbon-based raw material gases in a fluidized bed reactor at a high temperature. That is, the metal catalyst reacts with the raw material gas while floating in the fluidized bed reactor by the raw material gas to grow the carbon nanostructure.

A method for manufacturing a carbon nanostructure using a fluidized bed reactor is disclosed in Patent Application Publication No. 10-2009-0073346, No. 10-2009-0013503, and the like. In the case of using a fluidized bed reactor, a dispersing plate is used so that the gas is uniformly distributed in the reactor and powder such as catalyst existing on the dispersing plate does not pass below the dispersing plate. The dispersion plate is generally formed using a perforated plate, a bubble cap, a sieve, or a nozzle.

However, since the upward flow of gas is insufficient at the wall side of the fluidized bed reactor, powder and gas are not mixed well, and there is a problem that powder is accumulated at the edge of the dispersion plate. If the contact between the reaction gas and the catalyst is not uniform, growth to the carbon nanostructure is not smooth and the residence time is prolonged. Also, due to the phenomenon of unreacted catalyst being deposited on the dispersion plate or clogging of the dispersion plate Uniform injection of the reaction gas is obstructed and pressure drop occurs, which makes it difficult to operate the fluidized bed in a stable manner.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems described above, and it is an object of the present invention to provide a fluidized bed reactor capable of inducing smooth and uniform contact between a reaction gas and a catalyst by improving the phenomenon of accumulation of powder on the edge of a dispersion plate of a fluidized bed reactor, ≪ / RTI >

In order to achieve the above object, according to the present invention,

A reactor body having a reaction space formed therein;

A dispersion plate disposed within the reactor body; And

And a perforated plate having a plurality of through holes formed therein for separating the reaction space above the dispersing plate up and down and spaced apart from the inner wall of the reactor body by a predetermined distance therebetween.

According to a preferred embodiment of the present invention, a plurality of perforated plates may be vertically arranged at a predetermined interval to form a plurality of inner circulating unit fluidized beds.

According to a preferred embodiment of the present invention, the fluidized bed reactor is for a gas-solid reaction, and the downward flow of the solid particles mainly occurs at the inner center of the reactor body and the upward flow of gas mainly occurs at the wall surface of the reactor body .

According to a preferred embodiment of the present invention, the size of the through holes formed in the perforated plate is such that solid particles of a predetermined size can pass through.

According to a preferred embodiment of the present invention, the reactor body may be cylindrical and the perforated plate may be circular.

According to a preferred embodiment of the present invention, the fluidized bed reactor comprises

A catalyst supply pipe for supplying the catalyst into the reactor main body,

And a reaction gas supply pipe connected to the lower portion of the reactor to supply a reaction gas containing a carbon source, a reducing gas and an inert gas to the inside of the reactor through a dispersion plate,

The catalyst and the reactant gas react with each other in the plurality of inner circulating unit fluidized beds formed in the reactor body to react with each other to produce carbon nanostructure.

The present invention also provides a process for producing a catalyst, comprising: supplying a catalyst through a catalyst feed pipe of the fluidized bed reactor;

Supplying a reactive gas including a carbon source, a reducing gas, and an inert gas through a reactive gas supply pipe to supply the reactive gas into the reactor through the dispersing plate; And

And reacting the catalyst and the reactant gas in a plurality of inner circulating unit fluidized beds formed in the reactor body to react with each other to produce a carbon nanostructure.

In the fluidized bed reactor according to the present invention, the perforated plate is provided so as to be spaced a predetermined distance from the reactor wall surface in the reaction space, thereby enabling particle flow at the wall surface of the reactor to prevent particle accumulation at the edge of the dispersion plate, and stable fluidized bed operation is possible. Therefore, when a carbon nanostructure is manufactured using the fluidized bed reactor according to the present invention, a high quality product can be obtained with high yield.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic block diagram of an example of a fluidized bed reactor for producing carbon nanotubes. FIG.
2 is a cross-sectional view schematically illustrating gas and solid flow in a conventional spout fluidized bed.
3 and 4 are a perspective view and a cross-sectional view schematically showing the structure of a fluidized bed reactor according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail with reference to the embodiments of the invention shown in the accompanying drawings. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, or alternatives falling within the spirit and scope of the present invention.

In the drawings, like reference numerals are used for similar elements.

The terms first, second, A, B, etc. may be used to describe various components, but the components are not limited by these terms, and may be used to distinguish one component from another Only.

The term " and / or " includes any one or a combination of the plurality of listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it is to be understood that other elements may be directly connected or connected, or intervening elements may be present.

The singular expressions include plural expressions unless otherwise specified.

It will be understood that the terms "comprises", "having", and the like have the same meanings as the features, numbers, steps, operations, elements, parts or combinations thereof described in the specification, Does not exclude the possibility that an operation, component, component, or combination thereof may be present or added.

1 schematically shows the structure of a fluidized bed reactor, which fluidized bed reactor can be used, for example, in the production of carbon nanotubes, but is not limited to the manufacture of carbon nanotubes. Such fluidized bed reactors are useful for the production of carbon nanostructures such as, for example, carbon nanotubes or carbon nanofibers.

Referring to the drawings, a fluidized bed reactor 1 has a reactor body 10, and a lower portion of the reactor body 10 is formed as a tapered region 10a. In order to heat the reactor body 10 to a high temperature, it is preferable that a heater 19 is provided outside the reactor body 10.

A raw material gas supply unit 12 is provided at the bottom of the fluidized bed reactor 1. The raw material gas may be, for example, a hydrocarbon-based gas for producing carbon nanotubes. The raw material gas is supplied to the inside of the reactor main body 10 through a raw material gas supply pipe 21 connected to the raw material gas supply unit 12. The feed gas may be preheated in the preheater 17 before being fed into the reactor body 10. The raw material gas is dispersed into the reaction space in the reactor main body 10 through the dispersing plate 13 by disposing the dispersing plate 13 below the reaction space formed inside the reactor main body 10.

FIG. 1 shows a case where the dispersion plate 13 is provided at the upper end of the tapered region. However, the present invention is not limited thereto, and a dispersion plate may be provided by arbitrarily selecting the lower end of the tapered region in accordance with the purpose of the gas and solid. have.

On the upper portion of the reactor body 10, a stretching portion 11 is provided. The expander 11 may be provided with a separator (not shown) for preventing the catalyst and the reaction product (for example, carbon nanotube) from being discharged to the outside, for example, from the reactor body 10 . A filter 18 is connected to the elongated portion 11 and the component gas filtered by the filter 18 is conveyed through the conveying pipe 23. On the other hand, a recirculation pipe 22 is connected to the expansion part 11 to recirculate part of the mixed gas discharged from the expansion part 11 to the raw material gas supply pipe 21 through the recirculation pipe 22.

A separator 14 is connected to one side of the upper portion of the reactor main body 10 through a pipe 24. The separator 14 is for separating the product from the mixed gas discharged from the reactor body 10, for example, for separating the mixed gas from the carbon nanotube. A separator 14 is connected to one side of the reactor body 10 through a pipe 15 to collect a product such as carbon nanotubes. On the other hand, the catalyst supplier 16 is connected to the pipe 26 so that the catalyst can be supplied to the inside of the reactor main body 10 through the pipe 26. Although not shown in the drawing, the pipe 26 is provided with a blower so that the mixed gas separated from the separator 14 and the catalyst supplied from the catalyst feeder 16 can be fed into the reactor main body 10.

The dispersion plate 13 provided in the fluidized bed reactor as described above uniformly disperses the raw material gas into the fluidized bed reactor body 10 and the powder produced by the catalyst particles or the reaction drops to the bottom of the fluidized bed reactor . In the gas-solid fluidized bed reactor, when solid particles such as catalyst are placed on the dispersion plate and the reaction gas is blown from the bottom through the holes formed in the dispersion plate 13, the catalyst is supplied to the dispersion plate 13 of the fluidized bed reactor body 10, The reaction occurs while flowing in the upper space.

2 shows the gas / solid flow in the reactor 10 having the tapered region 10a as shown in Fig. 1 and in which the dispersion plate 13 is provided at the lower end of the tapered region 10a.

When gas is supplied through the diffuser plate, it mixes with the solid particles in the reactor and flows upward into the gas / solid mixed flow (100). The mixed flow 100 impinging on the reactor top is converted to a particle downflow 120 gas upward flow 130 in which the particles and gas are separated and descend along the wall while being subjected to a transverse mixing flow 110 towards some reactor walls . At this time, the falling particles are mixed with the rising gas and fluidized to form the mixed upward flow 100, but the flow rate of the wall is low, so that the particles tend to accumulate on the edge of the dispersion plate 13. As a result, the contact between the reaction gas and the particles is not uniform, so that the reaction does not proceed smoothly. As the particles block the pores of the dispersing plate, uniform injection of the reactive gas or pressure drop occurs, which makes stable fluidized bed operation difficult.

3 and 4 are a perspective view and a cross-sectional view schematically showing a fluidized bed reactor according to a preferred embodiment of the present invention.

As shown, the fluidized bed reactor according to the present invention comprises a reactor body 10 having a reaction space formed therein; A dispersion plate (13) disposed in the reactor body; And a perforated plate (40a, 40b, 40c) having a plurality of through-holes (40a, 40b, 40c) arranged on the upper surface of the dispersion plate (13) A reactor is provided.

3 and 4 illustrate a case where a plurality of perforated plates 40a, 40b and 40c are vertically arranged at a predetermined interval, but the present invention is not limited thereto, and one, two, or four or more perforated plates may be provided . It is possible to efficiently form the inner circulating unit fluidized bed in the reaction space by providing the required number of perforated plates according to the size of the reactor main body.

Here, the inner circulating unit fluidized bed refers to a unit fluidized bed in which both upflow, transverse and downward flows occur. 4 is a conceptual diagram showing that three unit fluidized beds can be formed by vertically arranging three perforated plates 40a, 40b, and 40c for vertically separating the reaction space.

According to a preferred embodiment of the present invention, the reactor body 10 is cylindrical as shown in FIG. 3 and the perforated plates 40a, 40b, 40c may be circular.

The diameter of the perforated plates 40a, 40b, 40c is smaller than the inner diameter of the reactor main body 10, so that the inner peripheral wall of the reactor and the outer peripheral portion of the perforated plate are separated by a predetermined distance. Through this gap upward flow 100 of gas or gas / solid may occur along the wall of the reactor.

The perforated plates 40a, 40b, 40c can be supported inside the reactor body 10 by a support structure not shown. For example, it can be supported in a predetermined position inside the reactor body 10 using a supporting beam or a cable.

According to a preferred embodiment of the present invention, the fluidized bed reactor is for a gas-solid reaction, and upward flow of gas 100 mainly occurs at the wall surface of the reactor body, and at the inner center of the reactor body, This can be done mainly.

In order to allow the solid particles to flow down through the through holes formed in the perforated plates 40a, 40b and 40c, it is preferable that the size of the through holes formed in the perforated plate is such that solid particles having a predetermined size can pass through.

As shown in FIG. 4, when the gas 100 supplied through the dispersion plate 13 flows upward and flows into the reaction space, the gas upward flow is interrupted by the perforated plates 40a, 40b and 40c, A gas or gas / solid mixed upward flow 100 is induced along the wall surface into the space between the walls.

In the inner circulating unit fluidized bed between the perforated plate and the perforated plate, a gas solid mixed upward flow (100) and a solid particle downward flow (120) are combined. As a result, the gas / solid mixed upward flow 100 takes place predominantly in the wall of the reactor body, and the downward flow 120 of the particles takes place predominantly in the center of the reactor body.

Therefore, unlike the flow shown in FIG. 2, the fluidized bed reactor according to the present invention increases the mixing efficiency of the reactants by the plurality of inner circulating unit fluidized beds in which the gas / solid mixed upward flow and the solid downward flow on the reactor wall surface are combined The accumulation of solid particles on the wall surface can be minimized. This structure is very effective for gas / solid reaction.

The dispersion plate 13 used in the fluidized bed reactor according to the present invention is not particularly limited as long as it is capable of gas communication and is selected from a metal foam, a perforated plate, a nozzle, a sieve, .

The dispersion plate may have a uniform opening ratio over the entire area, but it may include regions having different opening ratios if necessary. For example, in order to make the flow velocity of the gas injected into the reactor body uniform, it is also possible to configure the region where the gas inflow rate is relatively high, for example, the center region of the dispersing plate to have a lower opening ratio than the surrounding region.

According to a preferred embodiment of the present invention, the fluidized bed reactor comprises a catalyst supply pipe for supplying the catalyst into the reactor main body, and a reactive gas which is connected to the lower portion of the reactor and contains a carbon source, a reducing gas and an inert gas, And a reaction gas supply pipe for supplying the catalyst and the reaction gas to the interior of the reactor via a plate, wherein the catalyst and the reaction gas react with each other while flowing in the inner circulating unit fluidized bed of the reactor body to produce carbon nanostructure.

The present invention also relates to a process for the preparation of a catalyst, comprising: feeding a catalyst through a catalyst feed line of a fluidized bed reactor as described above;

Supplying a reactive gas including a carbon source, a reducing gas, and an inert gas through a reactive gas supply pipe to supply the reactive gas into the reactor through the dispersing plate; And

And reacting the catalyst and the reactant gas while flowing in an inner circulating unit fluidized bed of the reactor body to produce a carbon nanostructure.

The fluidized bed reactor according to the present invention has a structure in which a plurality of inner circulating unit fluidized beds are vertically arranged by providing a perforated plate so as to be spaced from the reactor wall surface by a predetermined distance in a reaction space in which the cross sectional area varies, It is possible to prevent particle accumulation at the edge of the dispersion plate and to operate the stable fluidized bed. Therefore, when a carbon nanostructure is manufactured using the fluidized bed reactor according to the present invention, a high quality product can be obtained with high yield.

10. Reactor body
10a. Tapered area
11. Extension
12. Feed gas
13. Dispersion plate
40a. 40b. 40c. Perforated plate

Claims (7)

A reactor body having a reaction space formed therein;
A dispersion plate disposed within the reactor body; And
And a perforated plate having a plurality of through holes formed therein for separating the reaction space above the dispersing plate up and down and spaced apart from an inner wall of the reactor body by a predetermined distance.
The method according to claim 1,
Wherein a plurality of perforated plates are vertically arranged at predetermined intervals to form a plurality of inner circulating unit fluidized beds.
The method according to claim 1,
The fluidized bed reactor is for gas-solid reaction,
Characterized in that a downward flow of solid particles occurs mainly in the inner center of the reactor body and an upward flow of gas mainly occurs in the wall surface of the reactor body.
The method according to claim 1,
Wherein the through holes formed in the perforated plate allow solid particles of a predetermined size to pass therethrough.
The method according to claim 1,
Wherein the reactor body is cylindrical and the perforated plate is circular.
6. The method according to any one of claims 1 to 5,
The fluidized bed reactor
A catalyst supply pipe for supplying the catalyst into the reactor main body,
And a reaction gas supply pipe connected to the lower portion of the reactor to supply a reaction gas containing a carbon source, a reducing gas and an inert gas to the inside of the reactor through a dispersion plate,
Wherein the catalyst and the reactant gas react with each other while flowing in a plurality of inner circulating unit fluidized beds formed in the reactor body to produce the carbon nanostructure.
Feeding a catalyst through a catalyst feed pipe of the fluidized bed reactor of claim 6;
Supplying a reactive gas including a carbon source, a reducing gas, and an inert gas through a reactive gas supply pipe to supply the reactive gas into the reactor through the dispersing plate; And
Reacting the catalyst and the reactant gas in a plurality of inner circulating unit fluidized beds formed in the reactor body to react with each other to produce a carbon nanostructure;
A method for producing a carbon nanostructure.

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