JP2016031204A - Powder burning burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable powder fuel at relatively large particle sizes of several mm to be burned to be suited for a particle size distribution by a small-sized burner.SOLUTION: Powder fuel 6 is supplied into a combustion chamber 2 from above the combustion chamber 2. Powder at small particle sizes contained in the powder fuel 6 is gasified and burned in a gasification combustion space 3 in an upper portion of the combustion chamber 2. A fluidized bed 4 is provided on a bottom of the combustion chamber 2, powder at relatively large particle sizes (about several mm) in the powder fuel 6 that cannot be burned in the gasification combustion space 3 in the upper portion of the combustion chamber 2 is gasified and burned in the bottom fluidized bed 4. As a result, even if the powder at relatively small particle sizes and the powder at relatively large sizes are contained in the powder fuel 6, this powder fuel can be used for a small-sized burner, so that it is possible to greatly improve the productivity of powder fuel and greatly reduce manufacturing cost.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a powder combustion burner used for combustion of powder, particularly powder fuel containing solid fuel having a relatively large particle size.

Among powder fuels, fossil fuels emit CO ₂ with combustion. One of the CO ₂ reduction measures is the use of biomass fuel produced by plant resources and the like that are expected to be effective as a measure against global warming because of low CO ₂ emissions other than fossil fuels.

  Biomass fuel is used in various fields as fuel for small-sized wood-burning stoves in households and large-scale power generation facilities, but the utilization rate of primary energy is only a few percent.

  When wood is taken as an example, biomass fuel is often used as a chip-shaped fuel of about 10 to 100 mm by crushing wood. In that case, since such chip-shaped fuel falls without being burned even if it is supplied to the combustion space, it cannot be used unless it is a combustion apparatus having a hearth. Since the time is long, the problem is that the combustion controllability is poor.

On the other hand, in the industrial field that requires heat in the production process and the like, not only CO ₂ measures but also fuel cost reduction is an important issue.

  In such industrial fields, not only fossil fuels but also solid waste fuels such as RPF manufactured from waste plastic, coal or oil coke, etc. are used as inexpensive fuels.

  Coal and oil coke are pulverized by a dedicated pulverizer and used as fuel for pulverized coal burners, etc., but solid waste fuels such as RPF are used in combustion devices having a hearth. .

  Therefore, in the future, not only biomass fuels but also more and more efficient use of various solid fuels will be necessary to reduce fuel costs.

  In order to improve the combustion controllability of a solid fuel such as a chip-shaped fuel of about 10 to 100 mm as described above, it is effective to pulverize the fuel. Like pulverized coal, fuel finely pulverized to about 100 μm behaves like a gas and can therefore be burned in a burner.

  However, in order to pulverize the solid fuel as described above, a special pulverization device is required, and equipment costs and operation costs are also required. Therefore, it is actually limited to use in a large combustion device. is there.

  Therefore, if the solid fuel can be used in the state of a pulverized fuel having a particle size of about several millimeters instead of being pulverized like pulverized coal, the productivity of the pulverized fuel is greatly improved. Fuel production costs can be significantly reduced.

In addition, if it can be used with pulverized fuel having a particle size of about several millimeters, it can be used with a smaller combustion device, and it can contribute to CO ₂ countermeasures and fuel cost reduction by expanding the use of pulverized fuel. .

  From such a viewpoint, conventionally, a fuel that uses a pulverized fuel having a particle diameter of about several millimeters has been proposed.

  For example, a cylindrical combustion chamber having a fire outlet at one end includes a fuel supply pipe that supplies primary air and powdered fuel to the combustion chamber, and a secondary air supply pipe that supplies secondary air. There is a powder combustion burner device in which both are connected in a tangential direction and powder combustion is combusted using a swirl flow in a combustion chamber (see, for example, Patent Document 1).

  As another example, waste plastics are injected into the industrial waste incinerator and burned in the industrial waste incinerator so that the inside of the industrial waste incinerator can be heated without overheating the burner body. There is a burner for powder combustion (for example, see Patent Document 2).

  As another example, even a combustible powder having a relatively large average particle diameter is burned well, and the inner peripheral surface of the auxiliary combustion chamber defined by the casing is expanded from the burner body side, There is a powder combustion burner in which the diameter is reduced on the furnace side so that the combustible powder travels through an enlarged flow path (see, for example, Patent Document 3).

  However, what is described in Patent Document 1 is to burn a powder fuel having a large particle size using a swirl flow, but a solid fuel having a particle size of about several millimeters is in a swirl flow. It cannot burn, and accumulates at the bottom of the combustion chamber and burns. Therefore, there is a risk of clinker and carbonization.

  Although what is described in Patent Document 2 is intended for waste plastic fuel having a particle diameter of 1 to 2 mm, it is possible to stably heat the inside of an industrial waste incinerator rather than burning it as a burner. To do.

  Although what is described in Patent Document 3 is intended for combustible powders having a relatively large average particle diameter, the flow path is enlarged when it is advanced into the sub-combustion chamber. It will burn. Therefore, there is a problem that pulverized fuel accumulates at the bottom of the auxiliary combustion chamber.

JP-A-8-270906 JP-A-10-185115 JP 2004-1000096 A

  Therefore, the present invention is directed to pulverized fuel containing powder having a large particle diameter such as 1 to 3 mm, and powder having a large powder diameter that cannot be burned in the combustion space is gasified and combusted. An object of the present invention is to provide a burner for powder combustion that can be made to be allowed to occur.

  In order to solve the above-mentioned problem, the present invention provides a fluidized bed at the bottom of the combustion chamber communicating with the flame outlet, as described in claim 1, and the combustion chamber has an upper portion of the combustion chamber. A gasification combustion space for connecting a pulverized fuel supply pipe for supplying pulverized fuel to the combustion chamber from above, and gasifying and combusting a small particle size powder in the supplied pulverized fuel at the upper portion of the combustion chamber The large particle size powder in the granular fuel that has fallen without being burned in the gasification combustion space is gasified and burned in the fluidized bed.

  Further, in the above configuration, the combustion chamber is formed in a vertically long shape, and a powder fuel supply pipe for supplying the pulverized fuel from the upper portion of the combustion chamber is connected to the top of the combustion chamber, and the supplied powder The powder having a large particle size in the fuel falls into the fluidized bed, or has a horizontally long shape of the combustion chamber, and is placed on the top of one end of the combustion chamber from the top of the combustion chamber. A pulverized fuel supply pipe for supplying fuel is connected, and the large particle size powder in the supplied pulverized fuel falls into the fluidized bed.

The powder combustion burner of the present invention exhibits the following excellent effects.
(1) The fine particle size powder in the pulverized fuel is combusted in the gasification combustion space, and the fuel having a large powder size that cannot be combusted in the gasification combustion space can be gasified and combusted in the fluidized bed.
(2) Even a fuel such as waste plastic having a high calorific value can be gasified and combusted, and no clinker or carbide is formed in the furnace.
(3) In the fluidized bed, the responsiveness of fuel gasification is good, so that pulverized fuel has good responsiveness and can be burned in the same manner as an oil-burning burner.
(4) Among powdered fuels, small particle size powder can be combusted in the upper gasification combustion space, so the fluidized bed can be made smaller and the bed height of the fluidized bed can be made shallower. The power of can be reduced.
(5) Since a pulverized fuel having a particle diameter of about several mm can be used, the production of the pulverized fuel can be greatly improved and the manufacturing cost can be greatly reduced.

It is a schematic side view which shows one Embodiment of the burner for powder combustion of this invention. It is a general | schematic cutting top view from the AA direction of FIG. It is a schematic side view which shows the other form of implementation of the burner for powder combustion of this invention. It is a general | schematic cutting | disconnection front view from the BB direction of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  1 and 2 show an outline of an embodiment of a powder combustion burner according to the present invention. 1 and 2 are shown in an easy-to-understand manner for convenience of explanation, and the size of each part is an example, and the present invention is not limited to this.

  The powder combustion burner of the present invention shown in FIGS. 1 and 2 forms a cylindrical combustion chamber 2 having a gasification combustion space 3 at the top inside a side wall 1, and a fluidized bed at the bottom of the combustion chamber 2. 4 Further, a pulverized fuel supply pipe 5 for supplying the pulverized fuel 6 transported by air is provided in the upper part of the combustion chamber 2, and a vertical flow capable of performing combustion suitable for the particle size distribution of the pulverized fuel 6 It is a layered burner structure.

  The gasification combustion space 3 formed in the upper part of the combustion chamber 2 is a part for gasifying and burning the small particle size powder in the pulverized fuel 6.

  A gas passage 7 is connected to the top of the combustion chamber 2.

  The end of the gas passage 7 is a flame outlet 8. A main combustion air supply pipe 9 is connected in the middle of the gas passage 7 so that main combustion air 10 is supplied to the gas passage 7 and main combustion is performed.

  A plurality (two in FIG. 1 and FIG. 2) of secondary air supply pipes 11 are arranged in a horizontal direction and connected in a tangential direction at a lower position of the gasification combustion space 3 in the combustion chamber 2. Thus, the secondary air 12 supplied from the secondary air supply pipe 11 becomes an upward flow toward the gas passage 7 while turning as indicated by an arrow in the combustion chamber 2, and the powder supplied from the pulverized fuel supply pipe 5. In contact with the body fuel 6, gasification combustion of the small particle size powder in the powder fuel 6 is performed.

  The fluidized bed 4 at the bottom of the combustion chamber 2 gasifies and combusts the large particle size powder in the pulverized fuel 6 with a heat medium such as sand fluidized by the fluidized air 13 introduced from below and ejected upward. Let

  The side wall 1 corresponding to the combusting section 14 of the fluidized bed 4 is provided with a starting (ignition) burner (not shown). In FIG. 1, 15 is an air box, 16 is an air diffuser, and 17 is a porous plate or a porous plate.

  In addition, the pulverized fuel 6 shall have a particle size distribution from 0.1 mm to 3 mm, for example. In the case of powder fuel made from wood, which is biomass fuel, if the wood is pulverized by a pulverizer and a sieve with a mesh of 3 mm or less is used, the powder has a particle size distribution of about 0.1 mm to 3 mm Fuel is obtained.

  The burner for powder combustion of the present invention gasifies and burns all of the powder fuel 6 for the powder fuel 6 having a particle size distribution of about 0.5 mm to 3 mm.

  When the start-up burner in the powder combustion burner of the present invention is started and the temperature of the combustion section 14 by the fluidized bed 4 at the bottom of the combustion chamber 2 is raised, the secondary air is supplied from the secondary air supply pipe 11. 12 is fed into the combustion chamber 2 while swirling. A powder fuel 6 having a particle size distribution from a small particle size to a large particle size is supplied from the powder fuel supply pipe 5. At this time, since the pulverized fuel 6 is transported with a slight amount of air, when it is supplied into the combustion chamber 2, air for transport is also introduced.

  The small particle size powder in the pulverized fuel 6 is ignited in the gasification combustion space 3 in contact with the secondary air 12 in combination with the high temperature inside the combustion chamber 2 of about 1100 ° C. Gasified and burned.

  The powder having a relatively large particle size in the pulverized fuel 6 that could not be combusted in the gasification combustion space 3 falls in the gasification combustion space 3 as it is against the ascending current.

  The powder having a relatively large particle diameter in the pulverized fuel 6 has been gasified and combusted by combustion in the fluidized bed 4.

  Thus, in the powder combustion burner of the present invention, the pulverized fuel 6 supplied to the gasification combustion space 3 above the combustion chamber 2 is in accordance with the gas flow and temperature conditions in the gasification combustion space 3. The relatively fine particle size fuel in the powder fuel 6 can be gasified and combusted in the gasification combustion space 3. A fuel having a relatively large particle size that cannot be gasified and combusted in the gasification combustion space 3 under the same conditions can be gasified and combusted in the fluidized bed 4 at the bottom. Thus, in the present invention, for example, even pulverized fuel having a particle size of about 3 mm can be easily gasified and combusted. At this time, in the fluidized bed 4, gasification combustion of the pulverized fuel 6 can be combusted with good responsiveness.

  In the present invention, even a fuel such as waste plastic having a high calorific value can be combusted suitable for the particle size distribution of the pulverized fuel. Thereby, even in the case of such a fuel, it does not accumulate and burn, and there is no possibility of forming clinker or carbide.

  Next, FIGS. 3 and 4 show an outline of another embodiment of the powder combustion burner of the present invention. FIG. 3 and FIG. 4 are also shown in an easy-to-understand manner for convenience of explanation, and the size of each part is an example, and the present invention is not limited to this.

  The powder combustion burner of the present embodiment is formed such that a cylindrical combustion chamber 2a is formed so as to be horizontally long inside the side wall 1, and an opening 18 is provided at the bottom on one end side of the combustion chamber 2a. Is provided. Further, a pulverized fuel supply pipe 5 is provided at the top of one end side of the combustion chamber 2 a to form a horizontal fluidized bed type burner structure capable of combustion suitable for the particle size distribution of the pulverized fuel 6.

  In the upper part of the combustion chamber 2a, a gasification combustion space 3 is formed over a range from a position immediately above the fluidized bed 4 to the other end side of the combustion chamber 2a. The gasification combustion space 3 is a region on the other end side of the combustion chamber 2a from the position of the two-dot chain line in FIG.

  The pulverized fuel supply pipe 5 provided at the top of one end of the combustion chamber 2a is connected in a tangential direction so as to open into the gasification combustion space 3 of the combustion chamber 2a, and the pulverized fuel 6 is swirled. Is supplied to the combustion chamber 2a.

  Further, a secondary air supply pipe 11 provided on the side wall 1 is connected to the combustion chamber 2a and opened in a tangential direction. As a result, the secondary air 12 supplied from the secondary air supply pipe 11 is swirled when supplied to the combustion chamber 2a. Thereby, both the secondary air 12 and the pulverized fuel 6 are supplied into the combustion chamber 2 a and swirled, and are brought into contact with each other in the gasification combustion space 3.

  A gas passage 7 is connected to the other end side of the combustion chamber 2 a, and an end portion of the gas passage 7 serves as a flame outlet 8.

  A main combustion air supply pipe 9 is opened from the side wall obliquely toward the flame outlet 8 at a position near the flame outlet 8 in the gas passage 7, and the main combustion air 10 is supplied in the direction of the flame outlet 8. It has come to be.

  Other configurations are the same as those shown in FIG. 1, and the same components are denoted by the same reference numerals.

  When the pulverized fuel 6 is burned by the pulverized combustion burner of this embodiment, the pulverized fuel 6 is supplied from the pulverized fuel supply pipe 5 into the combustion chamber 2a heated by the operation of the start burner. At the same time, the secondary air 12 is supplied from the secondary air supply pipe 11 while being swirled.

  The pulverized fuel 6 is supplied in the circumferential direction from the tangential direction into the combustion chamber 2a and falls while turning.

  On the other hand, the secondary air 12 is supplied in the circumferential direction from the tangential direction into the combustion chamber 2a and flows in the direction of the gas passage 7 as shown by the arrow while turning.

  The small particle size powder in the pulverized fuel 6 supplied into the combustion chamber 2a is ignited and gasified and combusted in the gasification combustion space 3 formed in the upper portion of the combustion chamber 2a.

  The large particle size powder in the pulverized fuel 6 that has not been burned in the gasification combustion space 3 falls as it is.

  In the present invention, since the fluidized bed 4 is present at the bottom of the combustion chamber 2 a, large particle size pulverized fuel that could not be combusted in the gasification combustion space 3 is gasified and combusted in the combustion unit 14 of the fluidized bed 4. Is done.

  Thus, the powder combustion burner of the present embodiment can also perform combustion suitable for the particle size distribution of the pulverized fuel 6, and can burn even fuel having a particle size of about 3 mm. This has the same effect as the embodiment shown in FIG.

  In the first embodiment shown in FIG. 1 and FIG. 2 and the second embodiment shown in FIG. 3 and FIG. 4, in the case of using the pulverized fuel 6 manufactured from waste plastic, the calorific value is large, so the pulverized fuel. It is preferable that the vicinity of the supply port of the supply pipe 5 can be cooled with water. The water cooling structure may be any structure as long as the vicinity of the supply port of the pulverized fuel supply pipe 5 can be protected from high temperatures.

DESCRIPTION OF SYMBOLS 1 Side wall 2,2a Combustion chamber 3 Gasification combustion space 4 Fluidized bed 5 Powder fuel supply pipe 6 Powder fuel 9 Main combustion air 12 Secondary air

Claims (3)

A fluidized bed is provided at the bottom of the combustion chamber communicating with the flame outlet,
A pulverized fuel supply pipe for supplying pulverized fuel to the combustion chamber from above the combustion chamber is connected to the combustion chamber;
In the upper part of the combustion chamber, a gasification combustion space for gasifying and combusting small particle size powder in the supplied pulverized fuel is formed,
A powder combustion burner, characterized in that the powder having a large particle size in the granular fuel that has fallen without being burned in the gasification combustion space is gasified and combusted in the fluidized bed. The combustion chamber has a vertically long shape, and a pulverized fuel supply pipe for supplying the pulverized fuel from the top of the combustion chamber is connected to the top of the combustion chamber,
The burner for powder combustion according to claim 1, wherein powder having a large particle diameter in the supplied pulverized fuel falls into the fluidized bed. As a horizontally long shape of the combustion chamber, a pulverized fuel supply pipe for supplying the pulverized fuel from the top of the combustion chamber is connected to the top of one end of the combustion chamber,
The burner for powder combustion according to claim 1, wherein powder having a large particle diameter in the supplied pulverized fuel falls into the fluidized bed.

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