JP2011094868A - Gas nozzle for fluidized bed type incinerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas nozzle for a fluidized bed type incinerator elongating residence time of fuel gas in a fluidized bed to increase the amount of fuel gas burned in the fluidized bed, capable of improving combustion efficiency of the fuel gas within the fluidized bed and capable of achieving the improvement of the fuel gas without changing the projecting direction of a fuel gas pipe to a furnace interior from an approximately horizontal direction. <P>SOLUTION: The fluidized bed 21 is formed in the lower part within an incinerator body 1, and an air diffusion means 3 for diffusing flowing air for flowing and stirring the fluidized bed 21 and an incinerated object mixed within the fluidized bed 21 is provided in the lower part within the fluidized bed 21. The gas nozzle 5 is provided in the fuel gas pipe 41 of the fluidized bed type incinerator, so that the projecting direction of the fuel gas pipe 41 jetting fuel gas to inside of the fluidized bed 21 and burning the fuel gas within the fluidized bed 21 to the furnace interior is set to be an approximately horizontal direction. The gas nozzle 5 includes a nozzle hole 50 of which fuel gas jetting direction is a slantly downward direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gas nozzle for a fluidized bed incinerator that incinerates an incinerated product by flowing a fluidized bed.

  Conventionally, fluidized bed incinerators have been used as waste incinerators or sewage sludge incinerators (see, for example, Patent Document 1). As shown in FIG. 4, the fluidized bed incinerator has a fluidized bed 21 formed by loading a fluidized medium in the lower part of the incinerator main body 1, and a freeboard 22 above the fluidized bed 21. Then, the incinerated material is put into the incinerator main body 1 and mixed into the fluidized bed 21, and fluidized and stirred by the fluidized air from the air diffuser 3 provided in the lower part of the fluidized bed 21. The fuel is injected into the fluidized bed 21 by the combustion means 4 provided in the combustion chamber, and the fluidized air is burned as combustion air (or mixed with air in the fuel gas) to be mixed into the fluidized bed 21. The incinerated material to be incinerated is incinerated uniformly and efficiently.

  The combustion means 4 includes a fuel gas pipe, and the fuel gas is ejected into the fluidized bed 21 by ejecting the fuel gas from the fuel gas pipe. When the fuel gas is ejected, the fluidized bed 21 is fluidized and agitated by the fluidized air, so that the fuel gas escapes immediately above the fluidized bed 21 without remaining in the fluidized bed 21, and the fuel gas in the fluidized bed 21. The combustion efficiency of was low.

  Moreover, in the conventional existing incinerator main body 1, as shown in FIG. 4, a through hole 10 penetrating in a substantially horizontal direction is formed in the furnace wall 11, and a substantially straight fuel gas pipe ( A gas gun 4a equipped with a gas gun (not shown) was inserted and protruded into the furnace in a substantially horizontal direction, and fuel gas was ejected from the gas nozzle at the tip of the fuel gas pipe to the side and burned. For this reason, even if it is intended to improve the combustion efficiency of the fuel gas by changing the direction in which the fuel gas pipe protrudes into the furnace, a large-scale remodeling work such as forming the through hole 10 at an angle is necessary and difficult. It was something.

JP 2000-81206 A

  The present invention has been made in view of the above points, and the object of the present invention is to increase the amount of fuel gas combusted in the fluidized bed by increasing the residence time of the fuel gas in the fluidized bed. The fluidized bed type can improve the combustion efficiency of the fuel gas in the inside, and can further improve the combustion efficiency without changing the protruding direction of the fuel gas pipe into the furnace from the substantially horizontal direction. An object of the present invention is to provide a gas nozzle for an incinerator.

  In order to solve the above problem, in the invention according to claim 1, a fluidized bed 21 is formed in the lower part of the incinerator body 1, and the fluidized bed 21 and the fluidized bed 21 are formed in the lower part of the fluidized bed 21. An air diffuser 3 for diffusing fluid air for fluidly stirring the mixed incinerated material is provided, and a fuel gas pipe 41 for injecting fuel gas into the fluidized bed 21 and combusting in the fluidized bed 21 is provided in the furnace. The gas nozzle 5 is provided in the fuel gas pipe 41 of the fluidized bed incinerator provided so that the protruding direction to the substantially horizontal direction, and has a nozzle hole 50 in which the fuel gas is ejected obliquely downward. It is a feature.

  In the present invention, the fuel gas does not escape immediately upward from the fluidized bed that is fluidly stirred as in the conventional example in which the fuel gas is simply jetted to the side. The fuel gas stays longer than the conventional example, and the fuel gas burns well in the fluidized bed to increase the combustion efficiency. Furthermore, since the direction of fuel gas injection into the furnace can be made obliquely downward while the direction of protrusion of the fuel gas pipe into the furnace is substantially horizontal, the direction of protrusion of the fuel gas pipe into the furnace is substantially horizontal. Even in an existing incinerator main body, it is possible to make the fuel gas ejection direction obliquely downward simply by replacing the fuel gas pipe.

1 shows an embodiment of a gas nozzle according to the present invention, in which (a) is a side sectional view, (b) is a front view, and (c) is a perspective view as viewed from the front oblique side. (A)-(c) is a front view of the other example of the gas nozzle same as the above, respectively. It is sectional drawing of the gas gun provided with the gas nozzle same as the above. 1 is an overall schematic diagram of a fluidized bed incinerator.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  In the fluidized bed incinerator, sludge, general waste, industrial waste, and the like are listed as incinerated materials, but there is no particular limitation.

  The incinerator main body 1 which is the main body of the fluidized bed incinerator is formed of a refractory material, and a fluid medium such as sand is loaded at the bottom of the incinerator main body 1 as shown in FIG. The fluidized bed 21 is formed with this fluidized medium. The fluidized bed 21 is provided with an air diffuser 3 a as the air diffuser 3, and fluid air is supplied to the air diffuser 3 a through the air supply path 12. A plurality of the air diffusion tubes 3a are arranged in parallel. The fluid medium and the incinerated material can be mixed and agitated by supplying fluid air from the air supply path 12 to the air diffuser 3a. Further, a gas gun 4a is disposed on the air diffusion pipe 3a as the combustion means 4, and fuel gas is ejected from the gas gun 4a into the fluidized bed 21 to form a flame in the fluidized bed 21 and burn. Yes. The gas gun 4a has a structure as shown in FIG. 3, and a main fuel gas pipe 41 and a pilot gas pipe 42 are provided in parallel in the outer pipe 40, and the fuel gas pipe 41 and the pilot gas pipe 42 are provided. Can be supplied with premixed fuel gas, which is a mixture of fuel gas and primary air. The fuel gas pipe 41 will be described later.

  In addition, an air introduction port 43 for introducing secondary air is provided at the base of the outer tube 40, and the secondary air introduced from the air introduction port 43 is taken in at the tips of the fuel gas tube 41 and the pilot gas tube 42. It comes to burn. A matrix 44 for avoiding a fluid medium such as sand is mounted in front of the front end of the outer tube 40.

  The upper part in the incinerator body 1 is a free board 22 (combustion chamber), and a temperature raising burner 15 is attached to the free board 22. This temperature raising burner 15 is combusted when the incinerator main body 1 is started up to heat the freeboard 22. Further, an incinerator input port 16 is provided in the upper part of the incinerator main body 1 to input an incinerator to be incinerated. An exhaust port 17 is provided at the upper end of the incinerator main body 1, and exhaust gas can be exhausted from the exhaust port 17 through the exhaust path 13 to the outside. A heat exchanger 14 is disposed in the middle of the exhaust path 13, and heat exchange is performed by the heat exchanger 14 with the flowing air supplied to the diffuser pipe 3a via the air supply path 12. The flowing air can be heated and supplied with gas. A discharge port (not shown) is provided at the lower end of the incinerator body 1.

  Next, the fuel gas pipe 41 will be described. As shown in FIG. 3, the fuel gas pipe 41 has a substantially circular cross section in the present embodiment, and the central axis of the substantially circular cross section extends linearly in the longitudinal direction. The cross section of the fuel gas pipe 41 may not be substantially circular and is not particularly limited, but the longitudinal direction (that is, the flow direction in the pipe) is formed in a substantially straight line.

  A gas nozzle 5 is provided at the tip of the fuel gas pipe 41 that protrudes into the free board 22. The gas nozzle 5 is mainly composed of a cover wall part 51 having a substantially truncated cone shape that covers and closes the front end opening of the fuel gas pipe 41 and a cylindrical part 52 that is provided continuously from the outer edge of the cover wall part 51. A substantially circular end surface 51 a that is a substantially truncated cone-shaped base part of the covering wall part 51 is provided so as to face the longitudinal direction of the fuel gas pipe 41. A through hole that becomes the nozzle hole 50 is formed in a part of the covering wall portion 51. The nozzle hole 50 is formed in the lower half of the substantially conical side surface 51b of the cover wall 51 so that the direction of fuel gas ejected from the nozzle hole 50 is obliquely downward. Here, the diagonally downward corresponds to an arbitrary angle from the horizontal direction to the vertically downward direction. 2A to 2C show other examples of the gas nozzle 5, respectively. FIG. 2A is an example in which a plurality of nozzle holes 50 are provided in the circumferential direction, and FIG. 2B is an example in which a plurality of rows having a plurality of nozzle holes 50 are provided in the circumferential direction. Further, as shown in FIG. 2 (c), the nozzle hole 50 may be formed in the end surface 51a, or may be formed in the upper half of the side surface 51b, and may be formed in at least the lower half.

  In the present embodiment, the tip shape of the gas nozzle 5 has a substantially truncated cone shape, but may be any shape as long as the ejection direction from the nozzle hole 50 is obliquely downward.

  The fuel gas used as fuel in the incinerator main body 1 is generally city gas, for example, natural gas called 13A. Such fuel gas is not limited to city gas, but may be propane gas or butane gas.

  In the fluidized bed incinerator, the incineration object is incinerated as follows. The incinerated material is introduced from the incinerated material inlet 16, and the incinerated material is mixed and stirred together with the fluid medium by the diffusing air of the flowing air. When the fluidized bed incinerator is started, the temperature raising burner 15 is burned and the fluidized bed 21 and the free board 22 are heated. A flame is ejected from the gas gun 4a into the fluidized bed 21, the fluidized bed 21 is heated, fluidized air is diffused from the diffuser 3a, the fluidized medium in the fluidized bed 21 is fluidly stirred, and the inside of the fluidized bed 21 is 800 ° C. The material to be incinerated is incinerated by being heated to the extent. At this time, the fuel gas is jetted obliquely downward from the gas nozzle 5 as in the present invention, so that the fuel gas is simply jetted laterally, and immediately above the fluidized bed 21 that is fluidly stirred as in the conventional example. The fuel gas does not escape, and the fuel gas stays longer in the fluidized bed 21 than in the above case, and the fuel gas burns well in the fluidized bed 21 to increase the combustion efficiency. The unburned gas that has not been burned in the fluidized bed 21 is burned by the free board 22.

  In the gas nozzle 5 of the present invention, as described above, the fuel gas is ejected obliquely downward from the gas nozzle 5 to increase the combustion efficiency, and the protruding direction of the fuel gas pipe 41 into the furnace is substantially horizontal. Also in the existing incinerator body which is the direction, the fuel gas ejection direction is set to be obliquely downward only by replacing the fuel gas pipe 41 provided with the gas nozzle 5 of the present invention (in other words, by simply replacing the gas nozzle 5). It becomes possible. Thus, it is not necessary to incline the longitudinal direction of the fuel gas pipe 41 for injecting the fuel gas to the side obliquely downward, and a large-scale modification such that the through hole 10 formed through the furnace wall 11 is formed obliquely. It is possible to make the fuel gas ejection direction obliquely downward without requiring construction.

  In addition, the present invention provides a remarkable effect when using a fuel gas having a specific gravity smaller than that of air, such as city gas or natural gas, which flows upward from the fluidized bed 21. The inventive gas nozzle 5 can be used.

DESCRIPTION OF SYMBOLS 1 Incinerator main body 10 Through-hole 11 Furnace wall 12 Air supply path 13 Exhaust path 14 Heat exchanger 15 Temperature rising burner 16 Incinerator inlet 17 Exhaust outlet 21 Fluidized bed 22 Free board 3 Air diffuser 3a Air diffuser 4 Combustion means 4a Gas gun 40 Outer pipe 41 Fuel gas pipe 42 Pilot gas pipe 43 Air inlet 44 Matrix 5 Gas nozzle 50 Nozzle hole 51 Covering wall part 51a End face 51b Side face 52 Cylindrical part

Claims (1)

  A fluidized bed is formed in the lower part of the incinerator main body, and a diffused means for diffusing fluidized air for fluidly stirring the fluidized bed and the incinerated material mixed in the fluidized bed is provided in the lower part of the fluidized bed, A gas nozzle provided in a fuel gas pipe of a fluidized bed incinerator in which a fuel gas pipe for injecting fuel gas into the fluidized bed and combusting in the fluidized bed is provided so that the protruding direction into the furnace is substantially horizontal. A gas nozzle for a fluidized bed incinerator having nozzle holes in which the direction of fuel gas ejection is obliquely downward.

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