JP2639885B2 - Waste incineration method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste incineration method for incinerating various industrial wastes including municipal waste and sludge, and an apparatus therefor.

[0002]

2. Description of the Related Art In general, this type of waste incineration method generally involves transferring and agitating waste such as garbage using a stair-type stoker in which a movable grate and a fixed grate are combined in a stepwise manner. A stoker-type incineration method in which combustion is performed and a fluidized-bed incineration method in which waste is caused to flow while burning by a fluidized bed formed on a furnace bottom are well known.

[0003]

According to the stoker-type incineration method, even when large-sized waste is contained, it can be incinerated as it is without performing pretreatment such as crushing. For high-calorie and lightweight paper such as municipal waste,
Since a large amount of plastic or the like is contained, the burning speed on the stoker increases, and the ash layer on the stoker is not sufficiently secured. Therefore, troubles such as burnout of the grate are likely to occur, and stable combustion is difficult. Moreover, since the stoker is generally composed of a dry stoker, a burning stoker, and a post-burning stoker, the burning loss of the incineration ash is large and the hearth load factor (about 200 Kg / m ² h) is small. Inevitably, the hearth becomes large and the whole furnace becomes unnecessarily large.

On the other hand, in the fluidized bed incineration method, the hearth load is large (about 500 kg / m ² h) as compared with the stoker furnace,
Moreover, ignition loss and stoppage are easy because the burning loss is 1% or less. However, since the combustion ratio varies greatly depending on the shape and properties of the waste supplied to the fluidized bed, it is necessary to perform pretreatment such as crushing in advance, and the treatment efficiency is poor.
The economic burden such as equipment costs and operating costs required for pre-treatment is large. Moreover, when crushing waste containing high calorie and lightweight materials as described above, the proportion of floating combustion increases,
The amount of combustion in the fluidized bed will decrease, and it will be difficult to maintain the fluidized bed at a predetermined temperature. Moreover, the crushed high-calorie and light-weight materials burn explosively, causing large pressure fluctuations in the furnace, resulting in insufficient CO for combustion.
This leads to a mass outbreak. As described above, the ratio of the combustion rate in the fluidized bed changes depending on the shape and properties of the waste, so that a stable fluidized bed temperature cannot be obtained and stable combustion is difficult. Also,
Since it is necessary to periodically discharge incombustibles together with the fluid medium from the center hole of the inverted pyramid-shaped furnace bottom, continuous operation cannot be performed for a long time, and the incineration efficiency is poor.

[0005] The present invention does not cause such a problem, and does not require any pretreatment such as crushing treatment, even if wastes of various shapes and properties are mixed, and can maintain a stable state. It is an object of the present invention to provide a waste incineration method capable of performing incineration satisfactorily and a waste incineration apparatus capable of suitably implementing the method.

[0006]

The waste incineration method according to the present invention, which has solved the above-mentioned problems, comprises a first incinerator and a first incinerator.
And a second combustion chamber are provided in a front-rear parallel manner, a first combustion chamber is provided with a stair-type stoker extending downward from the waste supply port to the rear, and a rear end portion of the stoker is provided in the second combustion chamber. A series of fluidized air jets comprising a steeply inclined portion extending downward from the position immediately below the rear and a gentle inclined portion extending downward and backward from the rear end of the portion to the incineration residue discharge port. A bed is provided, and a fluidized bed formed of a granular fluidized medium is formed on the fluidized air ejected from the gentle slope portion, and a smaller amount of fluidized fluid than necessary to form the fluidized bed is formed on the sharply sloped portion. A moving bed in which the granular fluidized medium flows slowly is formed on the portion by blowing out the bubbling air, and the waste supplied from the waste supply port to the first combustion chamber is stirred, dried, After being transferred backward while partially burning, By supplying to the combustion chamber, it is burnt in a moving bed and fluidized bed, and thereafter, in which the incineration residue containing incombustibles was to be discharged from the incineration residue 渣排 outlet. In such a method, the amount of combustion air supplied to the stoker and the feed rate of the waste by the stoker, that is, the forward and backward movement speed of the movable grate, are suppressed and maintained so that the combustion state of the waste on the stoker is dried and partially burned. So that
It is preferable to control based on the temperature of the first combustion chamber and the like. In particular, it is preferable to control the amount of combustion air within a range of 30% or less of the theoretical combustion air. Further, it is preferable that the air introduced from the rear end of the stoker toward the second combustion chamber causes the lighter waste to spread the waste brought to the rear end of the stoker.

In the waste incinerator according to the present invention for carrying out this method, first and second combustion chambers communicating with each other are provided in an incinerator in a front-to-back arrangement. A stair-type stoker is provided extending downward from the position immediately below the supply port to the rear, and is inclined downward from the position immediately below the rear end of the stoker to the rear in the second combustion chamber. A fluidized air spouting bed, the fluidized spouting bed comprising a gently inclined portion for ejecting a sufficient amount of fluidizing air to form a fluidized bed of a granular fluidized medium, and a stoker from the portion. And a steeply inclined portion that is more steeply inclined than the gentlely inclined portion and ejects a smaller amount of fluidizing air than necessary to form a fluidized bed. is there. In such an apparatus, it is preferable to further provide a wind selection mechanism for ejecting air from the rear end of the stoker toward the second combustion chamber. In addition, as for the inclination angle of the fluidized air ejection floor with respect to the horizontal plane, it is preferable that the steeply inclined portion is 30 ° to 70 ° and the gentle inclined portion is 10 ° to 25 °.

[0008]

The waste supplied from the waste supply port onto the stoker is agitated, dried and partially burned while being transferred on the stoker.

At this time, the hearth is divided into a stoker and a fluidized bed, and the stoker plays a role in stirring, drying, partially burning and supplying the waste to the fluidized bed. In addition, the total length is smaller than that in a normal stoker furnace (1/3 or less). Therefore,
Even when a large amount of high-calorie and light-weight materials such as plastic and paper are contained, only partial combustion (mainly, drying and gasification of waste) is performed on the stoker, and a sufficient thickness is provided on the stoker. Since the waste layer remains and is maintained, there is no trouble such as heat loss of the grate.
In addition, during the transfer on the stoker, the waste is only partially burnt as described above, and is mainly dried and gasified, and the shape and properties (calories, moisture content, etc.) are made uniform. Will be.

[0010] The waste brought to the rear end of the stoker is supplied to the moving bed and further brought to the fluidized bed, where it is completely burned while passing through both layers.

At this time, since the amount of supplied air is insufficient in the moving bed, even lightly combustible waste is not instantaneously burned by being supplied to the moving bed. In addition, in the moving bed, since the fluidized air ejection bed is constituted by a steeply inclined portion having a large inclination angle, a downward flow by the fluidized medium is formed. Therefore, the lightweight waste is quickly transferred to the fluidized bed by this flow, and is burned well.

By the way, if the waste is sprayed from the rear end of the stoker to the second combustion chamber by the air blown out by the wind selection mechanism, the lighter waste is far and the heavier waste is. Will be sprayed nearby, and the combustion of waste may be more appropriately performed according to its weight.

That is, the spraying distance of the waste by the jet air is such that non-combustible materials such as iron pieces, wires and stones and heavy combustible materials are mainly supplied to the moving bed without being sprayed far from the rear end of the stoker. The residence time in the moving bed and the fluidized bed becomes extremely long. Therefore, combustible materials that are heavy or large in shape and take a long time to burn will be completely burned in combination with pretreatment such as drying with a stoker. In addition, in the moving bed, since the floor is composed of a steep slope with a large inclination angle, the amount of ejected air is at least such that the heavy waste flows down smoothly and stays in the moving bed. There is no.

On the other hand, for light combustible materials that are easy to burn,
It is supplied directly to the fluidized bed and will be burned only by the fluidized bed. At this time, the lighter, the farther it is sprayed,
It will be supplied to the region on the rear side in the fluidized bed. That is, the lighter and easier to burn, the shorter the burning time. Therefore, the heat load in the fluidized bed is made uniform, and the combustion rate in the fluidized bed can be kept constant in combination with the treatment rate by the stoker, and stable combustion at a stable fluidization temperature is performed. . In addition, since the two combustion chambers communicate with each other, the combustible gas generated by partial combustion on the stoker and the combustion exhaust gas from the fluidized bed are mixed and completely burned by the supply of secondary combustion air. Become. Therefore, combustion on the free board is effectively performed, and the generation of CO is reduced. In addition, the transfer speed by the stoker depends on the shape of the waste supplied from the waste supply port,
Combustion in the fluidized bed can be stabilized by adjusting according to the change in properties.

[0015] From these facts, even when waste containing a large amount of volatile matter and having a high combustion rate is contained, rapid combustion is suppressed and stable combustion is performed. Moreover,
Dioxin generation can be reduced by complete combustion by the supply of secondary combustion air.

Further, heavy non-combustible substances settle at the bottom of the moving bed or fluidized bed. However, since the fluidized air ejection bed, which is the bottom, is inclined downward from the stoker side to the incineration residue discharge port, Combined with the fact that the front side portion of the bed is a steeply inclined portion having a large inclination angle, the bed smoothly flows down on the fluidized air ejection bed and is well discharged to the incineration residue discharge port. Therefore, it is not necessary to perform periodic cleaning as in a normal fluidized-bed furnace, and continuous operation can be performed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be specifically described below with reference to the embodiments shown in FIGS.

First, the configuration of the waste incinerator according to the present invention will be described. In this device, as shown in FIG.
A waste supply port 2 and an incineration residue discharge port 3 are provided on the front and rear walls of the incinerator 1, and the first and second combustion chambers 4, 5, the secondary combustion chamber 6, and the boiler section combustion chamber communicate with each other inside the furnace 1. 7 is provided.

A waste input hopper 8 is connected to the waste supply port 2, and a pusher 9 provided at a lower end chute portion 8a of the hopper 8 is moved forward and backward to remove dust, sludge and the like in the hopper 8. The waste 10 can be quantitatively supplied from the supply port 2 into the furnace 1. The supply port 2 is sealed by a stored waste 10 in the hopper 8 (a so-called material seal). In order to ensure the sealing, the opening of the upper surface of the hopper 8 can be sealed by the fire door 8b. It has become.

The first combustion chamber 4 is provided at a lower portion on the front side in the furnace 1. As shown in FIG. 1, the first combustion chamber 4 is inclined downward from the position immediately below the waste supply port 2 to the rear. An extended stair stalker 11 is provided.

The stoker 11 has a fixed grate and a movable grate provided in a stepwise manner, similarly to a conventionally known one, and the movable grate is moved in the front-rear direction by an appropriate driving device (not shown). Is reciprocated to supply port 2
The waste 10 supplied to the front end of the stoker 11 can be transported backward while being stirred. The feed speed of the waste 10 by the stoker 11, that is, the forward and backward movement speed of the movable grate, can be adjusted by controlling the driving device. Further, a wind box 12 is provided below the stoker 11, and combustion air is supplied from a combustion air supply pipe 13 connected to the wind box 12. The amount of combustion air supplied to the stoker 11 can be adjusted by controlling an air volume adjustment damper 13 a provided in the combustion air supply pipe 13. A ridling ash hopper 15 is provided below the stoker 11 so as to collect unburned ash and the like that fall from gaps between the grate.

Further, a temperature detector 19 for detecting the temperature of the first combustion chamber 4 is provided on the front wall of the first combustion chamber 4, and based on the temperature detected by the temperature detector 19, the air volume adjustment dampers 13a and 13a are provided. The grate drive is controlled. That is, the amount of combustion air supplied to the stoker 11 and the forward and backward movement speed of the grate, that is, the feed speed of the waste 10 are adjusted so that the temperature of the first combustion chamber 4 is maintained at the partial combustion temperature, that is, the waste 10 The combustion state by the stalker 11 is suppressed to partial combustion without leading to total combustion,
It is controlled to be maintained. In this case, the amount of combustion air supplied to the stoker 11 is controlled within a range of 30% or less of the theoretical combustion air amount. Therefore, the stoker 1 is pushed from the waste supply port 2 by the pusher 9.
The waste 10 supplied to the front end portion of the stoker 1 is dried and partially burned while being stirred while being transported on the stoker 11 to the rear end portion. By the way, since the stoker 11 does not aim at full combustion like a normal stoker, but aims at partial combustion, its overall length is necessarily shorter than a normal stoker. Specifically, the total length of the stoker 11 can be set to 1/3 or less of the stoker in the step-type stoker furnace described at the beginning.

A wind selection mechanism 20 as described below is attached to the rear end of the stoker 11, that is, the fixed grate 11a at the bottom.

That is, as shown in FIGS. 1 and 2, the wind selection mechanism 20 has a plurality of air ejection holes 21 (only one is shown) arranged in the left-right direction on the rear end wall of the lowermost grate 11a. And the air outlet 2 below the lowermost grate 11a.
1 are connected with an air supply pipe 23, and the air ejection pipes 21 are connected to the air headers 22.
To the second combustion chamber 5. In addition, the amount of gas ejected from the ejection holes 21 can be adjusted by an air volume adjustment damper 23 a provided in the air supply pipe 23. The air supply pipe 23 is branched and connected to the combustion air supply pipe 13, and uses a part of the combustion air as jet air.

The second combustion chamber 5 is provided at a lower rear portion in the furnace 1. As shown in FIGS. 1 and 2, the second combustion chamber 5 extends rearward from a position immediately below the rear end of the stoker 11. a series of fluidizing air consisting of a downward slope shape extending steeply inclined portion 14 ₁ and the rear end portion of the moiety 14 ₁ extends a downward inclined rearwardly reaches the incineration residue渣排outlet 3 gentle slope portion 14 ₂ which An ejection floor 14 is provided. That is, the fluidized air ejection floor 14 is provided with the refractory wall 2 erected below the rear end of the stoker 11.
4 and a refractory wall 25 which is a front wall of the incineration residue discharge port 3.

Steep part 14₁Is water as shown in FIG.
The inclination angle α with respect to the plane is gradually reduced._TwoAngle of inclination
Being larger than β, the floor panel 16₁Up
And a plurality of nozzles 17₁... in the left and right direction as the furnace width direction
Planted in parallel at regular intervals,₁Under
Wind box 18₁Fluidized air supplied to the nozzle 17₁… Or
It is constituted so that it may erupt. Wind box 18₁Flow
Branch pipe 26 of motive air supply pipe 26₁Is connected,
This branch pipe 26₁Air volume adjustment damper 27 ₁By
Nozzle 17₁… To control the amount of air blown out
ing.

Gently inclined portion 14_TwoIs as shown in FIG.
Fire wall structure floor panel 16_TwoUp the furnace width direction.
A plurality of nozzles 17 arranged in parallel at regular intervals_Two…(Less than
"Row nozzle group 17 '_Two")
The floor 16 _TwoSupplied to the lower wind box
The fluidized air is supplied to the row nozzle group 17 '._Two… I squirt from
It is configured as follows. In this embodiment, the wind box is
Le group 17 '_TwoThe number of wind boxes 18 corresponding to ..._TwoSplit into…
Together with these wind boxes 18_Two… In each fluidized air supply pipe
26 branch pipes 26_Two.. Are connected to each branch pipe 26._TwoSet in
Girder air volume control damper 27_TwoWith each row nozzle group 17
´_TwoIndependently adjusts the amount of fluidizing air ejected from
It is possible to do it. Note that the frontmost row nozzle group
17 '_TwoEach nozzle 17 constituting_TwoIs the steep slope 4₁
Each nozzle 17₁Is closely related to

Each nozzle 17 is, as shown in FIGS.
The upper and lower surfaces are inclined surfaces parallel inclined surfaces (the steep slope portion 14 ₁ of the nozzle 17 _first angle α to the floor plate 16, the gentle decline portion 1
4 ₂ nozzle 17 ₂ is formed as a hollow body having a mushroom cross section having an inclined surface having an angle β).
b is fixedly held by a mounting bracket 28 penetrated and fixed to the floor plate 16. On the left and right side walls of the bulging portion 17c, which is the upper part of the nozzle 17, as shown in FIG. 4 and FIG. The fluidizing air is ejected rearward and downward from each ejection hole 17a.

[0029] In Thus, the amount of air jetted from the gentle slope portion 14 _2, by adjusting the dampers 27 ₂ ..., partial 14 ₂
The amount is set to an amount sufficient to form a fluidized bed 30 with a granular fluidized medium (in this embodiment, sand is used) such as silica sand or alumina. Further, in this embodiment, the fluidized bed 30 is adjusted such that the rearward one of the horizontal nozzle groups 17 ′ ₂ .
A circulation flow 30a as shown in FIG. 2 is formed therein. That is, since the sand height in gentle slope portion 14 on ₂ are inclined downward to the rear is higher as going rearward, Tsu coupled with the fact that air is ejected toward the rear from the nozzles 17 ₂ As a result, the jet air is raised toward the lower side of the sand layer where the pressure loss is small, that is, obliquely forward, and as a result, the above-described circulation flow 30a is formed. The vertical distance between the rear end of the stoker 11 and the fluidized air spouting bed 14 is set so that the upper surface of the stationary bed portion in the fluidized bed 30 is not higher than the stoker 11. 1.5 of height
It is preferable to set it to about 2.5 times.

Further, the amount of air jetted from the steep part 14 _1, by adjusting the dampers 27 _1, is set to be less than the amount necessary to form a fluidized bed. Accordingly, a fluidized bed is not formed on the steeply inclined portion 14 _{1 as} on the gentlely inclined portion 14 ₂ ,
As shown in FIG. 3, I steep coupled with steep portion 14 _1, the granular bed material gentle downward flow by 2
The moving layer 29 which is a sand layer where 9a is generated is formed. Note that the constituent sand of the moving bed 29 is maintained at the same temperature as the sand temperature in the fluidized bed 30.

By the way, the inclination angle α of the steeply inclined portion 14 ₁
The heavy waste 10 supplied to the moving bed 30 in which a strong flow such as the circulating flow 30a is not formed is mixed with the portion 1
4 ₁ As can be caused to smoothly flow down without staying on the, preferably it is kept as 30 ° to 70 ° approximately, in this embodiment is set to approximately 40 °. Further, the inclination angle β of the gentle slope portion 14 _2, smoothly flows down I cooperation with the action of the circulation flow 30a, the weight of waste 10 of incombustible material or the like on the partial 14 ₂ to incineration residue渣排outlet 3 For the sake of simplicity, the angle is preferably set to about 10 ° to 25 °, and in this embodiment, it is set to about 20 °. Further, the inclination angle γ of the ejection hole 17a in the nozzle 17 (see FIG. 5)
Generally, it is preferable to set the moving bed 29, the fluidized bed 30, and the circulating flow 30a to about 30 ° to 60 ° so that the moving bed 29 and the circulating flow 30a can be formed and maintained well. Of course, the axial length of the ejection hole 17a is set so that the fluid medium does not enter the nozzle 17 from the ejection hole 17a in combination with the inclination angle γ.

As shown in FIG. 1, the secondary combustion chamber 6 is formed above the communicating portion between the first and second combustion chambers 4 and 5. On the peripheral wall of the secondary combustion chamber 6, secondary combustion air nozzles 31 are provided.
Are provided, and the nozzles 31...
A secondary combustion air supply pipe 32 branched from 3 is connected, and a part of the combustion air is ejected to the secondary combustion chamber 6 as secondary combustion air. By the supply of the secondary combustion air, unburned components in the exhaust gas rising from the combustion chambers 4 and 5 are secondarily burned. Note that the amount of secondary combustion air injected can be adjusted by an air volume adjustment damper 32 a provided in the supply pipe 32.

As shown in FIG. 1, the boiler section combustion chamber 7 is connected to the upper part of the secondary combustion chamber 6, and the exhaust gas from the secondary combustion chamber 6 is recovered by a boiler 7a for heat recovery. It is designed to be discharged outside. Further, the exhaust gas having passed through the boiler 7a is discharged from a chimney 35 via an appropriate dust collector 33 and an inducing fan 34.

Further, at the lower end of the incineration residue discharge port 3,
As shown in FIG. 1, an L-shaped incineration residue reservoir 36 is provided in series, and stores incineration residues (including incombustibles) discharged from the discharge port 3. The incineration residue stored in the incineration residue reservoir 36 seals the discharge port 3 similarly to the stored material 10 in the hopper 8. A pusher 37 is disposed in the incineration residue reservoir 36 so as to discharge the incineration residue onto the vibrating screen 38. The vibrating screen 38 has a water-cooled structure as required. The fluid medium contained in the residue discharged from the incineration residue reservoir 36 is separated from non-combustible materials and the like by the vibrating screen 38 and the second transfer is performed by the appropriate transport device 39.
The fluid is returned to the fluidized bed 30 from a fluidized medium supply port 5 a provided in the ceiling wall of the combustion chamber 5. Further, an unburned ash blowing nozzle 40 is provided on the rear wall of the second combustion chamber 5, and the unburned ash blowing pipe 41 branched from the fluidizing air supply pipe 26 and led to the nozzle 40 hangs down from the ridling ash hopper 15. An unburned ash recovery pipe 42 is connected to the second combustion chamber 5 so that the unburned ash recovered in the hopper 15 can be blown into the second combustion chamber 5 using a part of the combustion air. The blowing pipe 41 is provided with an air volume adjusting damper 41a for adjusting the blowing air volume.

The left and right widths of the waste supply port 2, the incineration residue discharge port 3, the hopper 8, the pushers 9, 37, the stoker 11, the fluidized air ejection floor 14, and the incineration residue reservoir 36 are the furnace width, that is, the incinerator 1 Approximately the left and right width (about 4 m).

The method of the present invention is performed as follows using the incinerator configured as described above.

That is, the waste 10 supplied from the waste supply port 2 to the first combustion chamber 4 is agitated, dried, and partially burned while being transferred backward on the stoker 11.

At this time, the total length of the stoker 11 is shorter (less than 1/3) as compared with a normal stoker in a stoker furnace.
Therefore, a waste layer having a sufficient thickness remains and is maintained on the stoker 11, and only the lightly flammable waste 10 existing on the upper part of the layer is burned. The waste 10 burns slowly while being stirred and transferred. Therefore, even when the waste 10 contains a large amount of high-calorie and lightweight materials, generation of suspended matter is extremely small, smooth and stable combustion is performed, and trouble such as heat loss of the grate does not occur. Further, even when wastes having different sizes are mixed, the shape is made uniform by combustion on the stoker 11. Further, the moist waste is transported over the stoker 11 over time, so that it is sufficiently dried during the time. As a result, even when the waste 10 is a mixture of substances having different shapes and properties, the waste 10 is mixed and stirred while passing through the stoker 11, so that the shape and properties are substantially uniformized. Moving bed 29 or fluidized bed 3
0 will be supplied. Furthermore, by controlling the forward and backward movement speed of the movable grate, the inside of the first combustion chamber 4 is maintained at a temperature at which the combustion state on the stoker 11 is suppressed to a dry state and a partial combustion state. And the combustion and temperature in the fluidized bed 30 are stabilized.

The waste 10 brought to the rear end of the stoker 11 is supplied to the air outlet 2 of the lowermost grate 11a.
Are sprayed to the second combustion chamber 5 by the air ejected from 1 and supplied to the moving bed 29 or the fluidized bed 30, where they are burned.

At this time, the scattering distance of the waste 10 by the ejected air is larger as the weight is smaller, and smaller as the weight is larger.
That is, light materials such as plastic and paper are scattered far and supplied to the fluidized bed 30, and non-combustible materials such as iron pieces, wires and stones and heavy combustible materials are far from the rear end of the stoker 11. , And is mainly supplied to the moving bed 29. Such spraying ability can be arbitrarily controlled by changing the ejection conditions from the ejection holes 21. For example, under the ejection conditions in which the air pressure is 50 mmH ₂ O and the air ejection speed is 40 m / s, the stoker 11 It can be sprayed up to 3 m from the rear end, and the bulk specific gravity of the waste in the spray area is 0.5 to 0.05 t.
/ M ³ .

Therefore, the lighter and easier to burn, the lighter the lighter, the rear side of the fluidized bed 30 (the incinerator residue discharge port 3 side).
And the combustion time by the fluidized bed 30 is shortened.
On the other hand, those which take a long time to burn because they are heavy or large in shape are slowly burned in the moving bed 29 where the gentle downward flow 29a is formed, and the fluidized bed 3
At 0, both layers 29, 30 will be completely burned with sufficient time.
That is, the longer the time required for complete combustion, the longer the residence time in both the layers 29 and 30 by supplying to the front side of the moving layer 29 so that the heavy waste 10 is reduced. It is possible to reliably burn regardless of the degree of its weight and shape. As described above, since the combustion time is given according to the type of the waste 10,
Combined with the pretreatment such as drying by the stoker 11 in advance, the waste 10 having any shape and properties can be satisfactorily burned.

Further, since the supply amount of air is insufficient in the moving bed 29 and a gentle downward flow 29a is formed, even when a large amount of waste 10 is supplied to the moving bed 29, Combustion occurs in both layers 29 and 30 in a sufficient and stable state without any significant combustion. Moreover, the weight wastes containing incombustible, since the inclination angle α of the steep part 14 ₁ is large, only a gentle downward flow 29a is formed transfer layer 2
Also in 9, it is allowed to smoothly flow down to the fluidized bed 30 and further to the incineration residue discharge port 3 without staying.

Accordingly, the waste 10 is efficiently and stably burned and incinerated in a low-oxygen atmosphere, in combination with the fact that the waste 10 is circulated in the fluidized bed 30 by the circulating flow 30a. Become. Further, since the two combustion chambers 4 and 5 communicate with each other, the combustible gas generated by the partial combustion on the stoker 11 and the combustion exhaust gas from the fluidized bed 30 are mixed, and the secondary combustion from the nozzles 31. Combustion is performed by the supply of air, and as a result, combustion on the freeboard is effectively performed, and CO generation is reduced.

The unburned ash dropped from the stoker 11 is blown into the rear region of the second combustion chamber 5 from the nozzle 40 using a part of the fluidized air, and is completely burned in the fluidized bed 30. become. Therefore, the amount of unburned ash can be reduced, and the incineration efficiency of waste can be greatly improved.

The heavy non-combustible material settles on the floor plate 16. Since the floor plate 16 has a large inclination angle α of the front end portion 16 ₁ , such non-combustible material is deposited on the floor plate 16. It flows down and flows smoothly on the top, and is reliably dropped and discharged to the incineration residue discharge port 3. 4 and 5
As shown in FIG. 5, the nozzles 17 are closely connected in the front-rear direction, which is the flow-down direction, and a series of flow-down passages 14a are formed between the cascaded nozzle groups 17. Is not hindered at all. Therefore, unlike a normal fluidized bed furnace, incombustibles do not stay or accumulate at the bottom of the fluidized bed, and the operation is not forced to be stopped due to a cleaning operation or the like. As a result, efficient incineration by continuous operation can be performed, and effective heat utilization by waste heat recovery means such as the boiler 7a can be realized.

Since a circulating flow 30a is formed in the fluidized bed 30 as shown in FIG. 2, and the amount of fluidized air ejected in the rear region of the fluidized bed 30 is increased, There is almost no possibility that unburned matter is discharged from the incineration residue discharge port 3. Therefore, there is no inconvenience due to the incineration residue discharge port 3 being opened below the fluidized bed 30. Of course, a very small part of the fluidized medium is
These may be discharged from the vibrating screen 38 together with the non-combustible material, and may be discharged from the screen 3.
In addition to being separated from non-combustible materials by 8 and returned to the fluidized bed 30 from the fluidized medium supply port 5a, no inconvenience occurs in such a case.

On the other hand, the exhaust gas generated in the first and second combustion chambers 4 and 5 reaches the secondary combustion chamber 6 and the boiler section combustion chamber 7, where unburned components and unburned gas contained in the exhaust gas are removed. Completely burned. At this time, the surplus of the combustion air supplied from the combustion air supply pipe 13 to the stoker 11 acts as secondary combustion air for secondary combustion of the exhaust gas from the fluidized bed 30, and the secondary combustion air nozzles 31. Combined with the air supply from the air, an effective secondary combustion function is exhibited. Therefore, in the furnace 1, stable combustion with a low excess air ratio can be obtained, and generation of CO and also dioxin can be effectively suppressed. The exhaust gas that has reached the boiler section combustion chamber 7 is cooled by heat recovery by the boiler 7a, and dust is removed by the dust collector 33, and then discharged from the chimney 35.

It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately improved and changed without departing from the basic principle of the present invention. For example, the composition ratio of the hearth, that is, the dimensional ratio in the front-rear direction of the hearth portion composed of the stoker 11 and the hearth portion composed of the moving bed 29 and the fluidized bed 30, and the front and rear portions of both the floor portions 14 ₁ and 14 ₂ The dimensional ratio of the length in the direction can be appropriately set according to incineration conditions such as the size of the furnace 1. In addition, the fluidized air ejection bed 14 may have any configuration as long as it can smoothly discharge and discharge the non-combustible material to the incineration residue discharge port 3. Needless to say, the waste heat recovery means attached to the furnace 1 is not limited to the boiler 7a but is optional.

[0049]

As will be easily understood from the above description, according to the waste incineration method of the present invention, it is possible to satisfactorily and stably burn waste of various types and shapes and properties. Can be. Moreover, without forcing the furnace to be large,
A large amount of waste can be incinerated efficiently and economically. Further, according to the waste incineration apparatus of the present invention, such a method can be suitably performed.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing one embodiment of a waste incinerator according to the present invention.

FIG. 2 is an enlarged detail view showing a main part of FIG. 1;

FIG. 3 is an explanatory diagram showing an enlarged main part of FIG. 2;

FIG. 4 is a vertical sectional front view taken along the line IV-IV in FIG. 2;

FIG. 5 is a cross-sectional plan view taken along the line VV of FIG. 2;

FIG. 6 is a perspective view of a nozzle.

[Explanation of symbols]

1 ... incinerator, 2 ... waste supply port, 3 ... incineration residue discharge port,
4 ... first combustion chamber, 5 ... second combustion chamber, 10 ... waste, 11
... stoker, 14 ... fluidized air ejection bed, 14 ₁ ... steeply inclined portion, 14 ₂ ... gentle inclined portion, 20 ... wind separation mechanism, 29 ... moving bed, 29a ... downward flow of granular fluidized medium, 30 ... fluidized bed, 30a: Circulating flow, α, β: Angle of inclination of fluidized air ejection bed with respect to horizontal plane.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location F23G 5/50 ZAB F23G 5/50 ZABC ZABG

Claims (8)

(57) [Claims] 1. A first and a second communicating with each other in an incinerator.
Combustion chambers are provided in front and rear side-by-side, a first combustion chamber is provided with a stair-type stoker extending downward from the waste supply port and inclined downward, and a second combustion chamber is provided at a position directly below a rear end of the stoker. A series of fluidized air jet beds consisting of a steeply inclined portion extending downward from the rear and a gentle inclined portion extending downward from the rear end to the incineration residue discharge port is provided. Further, a fluidized bed formed of a granular fluid medium is formed on the portion by the fluidized air ejected from the gentle slope portion, and a smaller amount of fluidized air than the amount required to form the fluidized bed is formed from the steeply sloped portion. A moving bed in which the granular fluid medium flows slowly is formed on the portion by jetting, and the waste supplied from the waste supply port to the first combustion chamber is agitated, dried, and partially burned by a stoker. The second combustion chamber So supplied, it is combusted in the moving bed and fluidized bed, after which the waste incineration process being characterized in that so as to discharge the incineration residue containing incombustible from incineration residue 渣排 outlet. 2. The method according to claim 1, wherein the amount of combustion air supplied to the stoker is controlled so that the combustion state of the waste on the stalker can be suppressed and maintained to be dry and partial combustion. Waste incineration method. 3. The combustion air amount is 30% of the theoretical combustion air amount.
3. The waste incineration method according to claim 2, wherein the method is controlled in the following range. 4. The moving speed of a movable grate in a stoker is controlled so that the combustion state of waste on a stalker can be suppressed and maintained to be dry and partial combustion. The waste incineration method according to claim 1, 2, or 3. 5. The stoker is characterized in that, by blowing air from the lowermost part of the stalker toward the second combustion chamber, lighter wastes that are brought to the rear end of the stalker are dispersed farther. The waste incineration method according to claim 1, claim 2, claim 3, or claim 4. 6. A first and a second communicating with each other in an incinerator.
Combustion chambers are provided side by side in a front-rear direction, a first combustion chamber is provided with a stair-type stoker extending downward from the position immediately below the waste supply port to the rear, and a second combustion chamber is provided with a rear end of the stoker. A fluidized air spouting bed extending downward from the position directly below to the rear and inclining to the incineration residue discharge port, the fluidizing spouting bed having a sufficient amount to form a fluidized bed by the granular fluidized medium. A gently inclined portion for ejecting fluidized air, and a portion on the stoker side with respect to the portion, which is steeply inclined from the gently inclined portion and ejects a smaller amount of fluidized air than the amount required to form a fluidized bed. A waste incineration apparatus characterized by comprising an inclined portion. 7. The inclination angle of the fluidized air ejection floor with respect to the horizontal plane is 30 ° to 70 ° for a steeply inclined portion,
7. The waste incinerator according to claim 6, wherein the angle of the gentle slope is 10 ° to 25 °. 8. The waste incinerator according to claim 6, further comprising a wind selection mechanism for blowing air from a rear end of the stalker toward the second combustion chamber.