JPH05180427A - Fluidized bed incinerator for waste - Google Patents

Abstract

PURPOSE:To provide the title incinerator in which unstable burning is not caused, by a method wherein a fluidized bed is divided into a plurality of divisions and supplied gas can be independently controlled at each of the division. CONSTITUTION:At the inside of a space 4, in which waste is pyrolyzed as the major function, two shield plates 10, 11 are provided and the space is divided into three divisions, i.e., a drying division 12, a pyrolyzing and gasifying division 13 and a carbides-burning division 14. At the bottom of an incinerator 1, diffusers 15, 16, 17, each of which consists of a diffusing plate and a wind box, are individually fixed corresponding to these three divisions. Inert gas such as exhaust gas is supplied into an inert gas-supplying pipe 19 by a blower 18 and it is joined respectively to the diffusers 15, 16, 17 through flow control valves 20, 22, 24 and pipes 21, 23, 25. On the other hand, the primary air is supplied into an air-supplying pipe 28, and it is joined respectively to the diffusers 16, 17 through flow control valves 29, 31 and pipes 30, 32. Pyrolyzing- gasifying and burning each are independently done at the divisions for these purposes, by controlling these flow control valves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed waste incinerator having a fluidized bed formed at the bottom of a space whose main function is thermal decomposition and having a gas combustion chamber above the space. ..

[0002]

2. Description of the Related Art An example of a conventionally used fluidized bed type waste incinerator will be described with reference to a perspective view showing a partially cutaway view of FIG.
The dust collector a supplies the fluidized bed waste incinerator b. The bottom of the fluidized bed waste incinerator b is filled with sand c, and in order to make the sand c flow, a header d that supplies primary air to the bottom of the fluidized bed waste incinerator b. Is provided with an air diffusing tube e. The sand c is fluidized by the primary air blown out from the air diffuser e to form the fluidized bed l, and the waste supplied to the fluidized bed waste incinerator b by the dust supply machine a is mixed and burned. ing. The sand c forming the fluidized bed 1 passes through the sand discharger f, the sand feeder g, and the sand circulation conveyor h attached to the bottom of the fluidized bed waste incinerator b, and again incinerates the fluidized bed waste. It is supplied into the furnace b and is circulated for use.

The incombustibles generated in the fluidized bed waste incinerator b are discharged to the outside of the fluidized bed waste incinerator b by the incombustible material transport conveyor i, and the combustion exhaust gas is recovered by the boiler j after heat recovery. Through the air preheater k, dust is removed by an electric dust collector (not shown) and discharged from the chimney.

[0004]

The conventional fluidized bed type waste incinerator b shown in FIG. 3 has a fluidized bed formed by sand c and diffusers such as diffusers e for supplying fluidized gas. There is one device for the entire fluidized bed waste incinerator b,
In addition, since the primary air plays two roles of the gas for fluidization and the oxygen supply gas for combustion, gasification and
Even when it is desired to suppress combustion in the process of thermal decomposition, it has been sometimes impossible to suppress combustion because the minimum required air must be supplied for fluidization.

Further, since drying, gasification and pyrolysis, and combustion occur simultaneously in a short time, it is not possible to adjust the primary air and the secondary air to the fluctuation of the calorie of the waste and the fluctuation of the water content, and the fluctuation of CO and the like are unstable. It may have caused combustion.

The present invention overcomes these drawbacks of the prior art,
The fluidized bed can be divided into multiple compartments, and the supply gas can be adjusted for each compartment, so that thermal decomposition and gasification can be performed completely, and combustion of gasified matter and combustion of solid matter etc. can be completely combusted. It is an object of the present invention to provide a fluidized bed type waste incinerator in which unstable combustion does not occur so as to be possible.

[0007]

The fluidized bed type waste incinerator of the present invention has a fluidized bed formed at the bottom of a space whose main function is thermal decomposition of the lower part and a gas combustion chamber above the space. In a floor-type waste incinerator, the space and the fluidized bed are divided into two or more sections by a shielding plate, and an inert gas supply pipe is connected to the bottom of each section via a flow rate adjusting valve or a flow rate adjusting valve. Characterized in that an inert gas supply pipe and an air supply pipe are connected via a gas combustion chamber above the space by forming a fluidized bed at the bottom of the space whose main function is thermal decomposition of the lower part. In the fluidized bed type waste incinerator having two, the space and the fluidized bed are divided into three sections, that is, a drying section, a pyrolysis / gasification section, and a combustion section for carbides, which are adjacent to each other by two shielding plates. Inert through the flow control valve at the bottom of the Gas supply pipe is connected, and an inert gas supply pipe and an air supply pipe are connected to the pyrolysis / gasification section and the combustion section such as carbides following the drying section via flow rate adjusting valves, respectively. Is.

[0008]

By adjusting the opening of the flow rate adjusting valve, thermal decomposition and gasification are completely performed in one section, and combustion is completely performed in the other section.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIG.
2 is a sectional view taken along the line II-II in FIG. 1, and as shown in FIG. 1, a constricted portion 2 is formed in the middle of the fluidized bed waste incinerator 1 in the height direction, and a constricted portion 2 is formed above the constricted portion 2. Is the gas combustion chamber 3
Below the constricted portion 2, there is a space 4 whose main function is thermal decomposition, and at the bottom of the fluidized bed waste incinerator 1, sand 5 forming a fluidized bed 41 is placed. .. One side of the bottom of the fluidized bed waste incinerator 1 (left side of FIGS. 1 and 2)
Is connected to the lower end of a dust chute 7 having a dust collector 6 at the upper end, and a circulating sand supply port 8 for supplying the sand 5 is mounted above the dust chute 7. The bottom of the fluidized bed waste incinerator 1 is gently inclined so as to decrease from one side toward the other side (right side of FIGS. 1 and 2). A sand and non-combustibles discharge port 9 is connected to the other side.

Two shield plates 10 and 11 are provided inside the space 4 whose main function is thermal decomposition. The space 4 whose main function is thermal decomposition is sand and non-combustible from the dust chute 7. It is divided into three sections, in order toward the material discharge port 9, a drying section 12, a thermal decomposition / gasification section 13, and a combustion section 14 such as carbides. Each of the two shield plates 10 and 11 has an upper end supported by a horizontal shaft, and can be rotated left and right around the upper end as a rotation center as shown by a two-dot chain line in FIG. There is. The drying section 12 and the pyrolysis / gasification section 13 are partitioned by a shielding plate 10, and the pyrolysis / gasification section 13 and the combustion section 14 for carbides and the like are partitioned by a shielding plate 11, but are shielded. The partition by boards 10 and 11 is
Only a few mm of water column pressure difference can be maintained between the adjacent compartments, and the gas in each compartment is between the upper ends and both side edges of the shielding plates 10 and 11 and the inner surface of the fluidized bed waste incinerator 1. Gap,
In addition, it can flow to the adjacent section through the void in the sand 5 below the lower ends of the shielding plates 10 and 11.

At the bottom of the fluidized bed-type waste incinerator 1, a diffusing plate and a wind box are provided corresponding to three sections, a drying section 12, a pyrolysis / gasification section 13, and a combustion section 14 for carbides and the like. The air diffusers 15, 16, and 17 are attached. Then, an inert gas such as exhaust gas from the outlet of a dust collector (not shown) is supplied to the inert gas supply pipe 19 by the blower 18, and the inert gas supply pipe 19
Is the air diffuser 15 through the flow rate adjusting valve 20 and the pipe 21.
Then, through the flow rate adjusting valve 22 and the pipe 23, the air diffuser 16
Then, through the flow rate adjusting valve 24 and the pipe 25, the air diffuser 17
, Respectively. In addition, the primary air blower 26
Primary air from the air preheater 27 through the air supply pipe 28
The air supply pipe 28 is connected to the air diffuser 16 via the flow rate adjusting valve 29 and the pipe 30, and is connected to the air diffuser 17 via the flow rate adjusting valve 31 and the pipe 32, respectively. Has been done.

A pair of semicircular radiant heat adjusting devices 33 (see FIG. 2) is provided above the thermal decomposition / gasification section 13. The two semicircular radiant heat adjusting devices 33 are supported on a horizontal shaft, and rotate as shown by the chain double-dashed line in FIG. 1 to open between the pyrolysis / gasification section 13 and the constricted section 2. You can change the degree.

A gas flow distributor 34 and an exhaust gas outlet 35 are provided above the gas combustion chamber 3.
On the outer side of the constricted portion 2 and the annular pipe 36 for supplying combustion air,
37 and 38 are provided to supply combustion air into the fluidized bed waste incinerator 1 via the flow rate adjusting valves. Further, a burner 39 for ignition and flame holding is attached to the gas combustion chamber 3 for thermal decomposition and
A burner 40 that supplies heat for thermal decomposition / gasification is attached to the gasification section 13.

Next, the operation will be described.

Waste such as dust to be incinerated is supplied to the drying section 12 from the dust feeder 6 via the dust chute 7. The sand 5 supplied from the circulating sand supply port 8 is the fluidized bed 4
1 is formed, and a part of it is taken out from the sand and incombustibles discharge port 9 and is again supplied to the circulating sand supply port 8 for cyclic use.

Sand 5 is generated by the inert gas at 150 to 200 ° C. supplied from the air diffuser 15 under the drying section 12.
Is fluidized and the waste is dried. At this time, the air diffuser 1
The difference between the gas temperature in 5 and the gas temperature in the drying section 12 is detected, and the opening of the flow rate adjusting valve 20 is adjusted to sufficiently dry the waste.

The waste dried in the drying section 12 enters the pyrolysis / gasification section 13 together with the flowing sand 5, and is fluidized by the mixed gas of the inert gas and the primary air supplied from the air diffuser 16. Part of the waste is burned to generate heat necessary for pyrolysis and gasification, and the pyrolysis / gasification section 13
To raise the temperature of and accelerate the thermal decomposition and gasification of waste. In the thermal decomposition / gasification section 13, for example, the gas temperature and the amount of residual oxygen in the thermal decomposition / gasification section 13 are detected, and the total amount of the mixed gas of the inert gas and the primary air is set within an appropriate range for fluidization. By controlling the amount of oxygen supplied by the primary air while maintaining the temperature, suppressing the combustion of the waste and maintaining the temperature, the gasification and thermal decomposition of the waste are promoted. If necessary, the radiant heat adjusting device 33 is adjusted to adjust the thermal decomposition / gasification section 13.
It is also possible to help control the temperature of the above, and it is also possible to supply heat for a short time by the burner 40.

The carbonized waste, the residue, and the sand 5 enter the combustion section 14 for carbides and the like from the pyrolysis / gasification section 13, and in the combustion section 14 for carbides and the like, the above-mentioned pyrolysis / gasification section is also used. Similar to 13, it is fluidized by the mixed gas of the inert gas and the primary air supplied from the air diffuser 17, and the carbides and the like burn. In the combustion section 14 for carbides and the like, CO and residual oxygen are detected and the ratio of primary air is adjusted while maintaining fluidization as described above to supply necessary and sufficient oxygen to promote combustion of carbides and the like.
The shielding plates 10 and 11 are configured so that the required widths of the drying section 12 and the combustion section 14 such as carbide can be changed according to the fluctuation of the quality of the waste, and are fixed to the shaft outside the fluidized bed waste incinerator 1. Shielding plate 1 by driving the lever
0 and 11 rotate about the axis of the upper end.

The gas gasified in the thermal decomposition / gasification section 13 rises and enters the gas combustion chamber 3 and is burned by the combustion air supplied from the combustion air supply annular pipes 36, 37 and 38 to become exhaust gas. And is discharged from the exhaust gas outlet 35. The flow of the exhaust gas at this time is improved by the gas flow distributor 34.

The space 4 whose main function is thermal decomposition is a drying section 12, a thermal decomposition / gasification section 13, a combustion section 1 for carbides and the like.
Ideally, it should be divided into three sections of four, but it is possible to simplify the device at the expense of some performance. In this case, the shielding plate 10 is omitted, and the drying section 12 and the thermal decomposition / gasification section 13 are combined into one section, and the diffusers 15 and 16 are combined into one diffuser. In addition, one diffusing tube type diffusing device is provided as one unit combining the drying section 12 and the non-decomposition gasifying section 13, and the diffusing apparatus in the combustion section 14 for carbides and the like remains the diffusing plate system. The forms of the equal diffuser can be implemented in various combinations.

The space 4 whose main function is thermal decomposition of the present invention can be applied regardless of the structure of the gas combustion chamber 3.

[0023]

INDUSTRIAL APPLICABILITY The present invention makes it possible to achieve proper fluidization in a drying section and to achieve only drying without combustion of waste, and to achieve a dryness target. The amount of active gas supplied can be adjusted within a range that does not adversely affect fluidization.

In the pyrolysis / gasification section, the gas temperature, the amount of residual oxygen, etc. are kept in appropriate ranges, and the total amount of the inert gas and air is kept in a certain range in order to promote the pyrolysis / gasification. The fluidization can be properly maintained, and the oxygen amount necessary and sufficient for the partial combustion and the gasification can be supplied by adjusting the ratio of air to accelerate the gasification. Similarly, even in the combustion section for carbides, it is possible to supply sufficient oxygen while maintaining proper fluidization.

Furthermore, since it is possible to prevent the occurrence of locally high heat load locations due to local combustion, etc., and to complete the respective actions for each section, stable incineration of the entire fluidized bed waste incinerator is possible. Since it is possible to carry out the above, and the state of excess oxygen does not occur, the generation of NOx can be suppressed and the combustion temperature in the gas combustion chamber can be maintained at a stable temperature of 850 ° C. or higher, so that the generation of dioxins and the like can also be suppressed. ..

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view showing a part of the conventional device by cutting.

[Explanation of symbols]

 1 Fluidized Bed Waste Incinerator 3 Gas Combustion Chamber 4 Space with Pyrolysis as its Main Function 10 Shielding Plate 11 Shielding Plate 12 Drying Section 13 Pyrolysis / Gasification Section 14 Carbide Combustion Section 19 Inert Gas Supply Pipe 20 Flow Adjustment valve 22 Flow rate adjustment valve 24 Flow rate adjustment valve 28 Air supply pipe 29 Flow rate adjustment valve 31 Flow rate adjustment valve 41 Fluidized bed

Claims (2)

[Claims] 1. A fluidized bed waste incinerator having a fluidized bed formed at the bottom of a space having a lower pyrolysis function as a main function and having a gas combustion chamber above the space, and the space and the fluidized bed with a shield plate. Is divided into two or more compartments, and an inert gas supply pipe is connected to the bottom of each compartment via a flow rate adjusting valve, or an inert gas supply pipe and an air supply pipe are connected via a flow rate adjusting valve. A fluidized bed waste incinerator characterized by the following. 2. In a fluidized bed type waste incinerator having a gas combustion chamber above the space, a fluidized bed is formed at the bottom of the space whose main function is thermal decomposition of the lower part, Fluidized bed and adjacent drying section, pyrolysis
It is divided into three sections, a gasification section and a combustion section such as carbide, and an inert gas supply pipe is connected to the bottom of the drying section via a flow rate control valve, and a pyrolysis / gasification section and a carbide etc. following the drying section. A fluidized bed waste incinerator characterized in that an inert gas supply pipe and an air supply pipe are connected to each of the combustion sections via flow control valves.