JP3764634B2 - Oxygen burner type melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to incineration ash discharged from a stoker-type incinerator or fluidized bed incinerator for incinerating waste such as municipal waste and industrial waste, and incineration fly ash collected by the exhaust gas treatment equipment of each incinerator In particular, the present invention relates to a fuel combustion type oxygen burner melting furnace in which incineration fly ash and incineration ash are melted by the combustion heat of fossil fuels such as kerosene and natural gas. .
[0002]
[Prior art]
In general, most of waste such as municipal waste is incinerated by a stoker-type incinerator or a fluidized bed incinerator. In the former stoker type incinerator, incineration ash that remains in the furnace as incineration residue and incineration fly ash that is taken out into the exhaust gas and collected by exhaust gas treatment equipment such as a dust collector are generated. Further, in the latter fluidized bed incinerator, due to its structure, all incineration residue is collected as incineration fly ash by an exhaust gas treatment facility.
[0003]
By the way, incineration ash discharged from a stoker-type incinerator generally contains coarse substances, and thus pretreatment such as magnetic substance removal and particle size selection is required before melting treatment, but the melting point is relatively low.
On the other hand, the incineration fly ash collected by the incinerator exhaust gas treatment equipment not only contains a large amount of volatilized components such as powdered low boiling point heavy metals and dioxins, but also exhaust gas in the exhaust gas treatment equipment. Slaked lime Ca (OH) as a treatment for acidic gas such as HCl and SOx ₂ When a dry treatment is performed by blowing in, high basicity (CaO / SiO ₂ ) And a high melting point substance.
[0004]
Therefore, in recent years, in order to reduce the volume, detoxify, and stabilize the incineration ash and the incineration fly ash, the melting and solidifying treatment of the incineration ash and the incineration fly ash has attracted attention and is actually put into practical use. In particular, incineration fly ash has a higher concentration of dioxins and a heavy metal content than incineration ash, and is strongly required to be melted and solidified.
[0005]
For melting of incineration ash and incineration fly ash, fuel combustion type melting furnaces (for example, surface melting furnaces, swirl melting furnaces, coke bed furnaces) that use the heat of combustion of fossil fuels such as kerosene and natural gas, and electric energy There is an electric melting furnace (for example, an arc melting furnace, a plasma arc furnace, an electric resistance furnace) or the like that uses as a heat source. In general, an electric melting furnace is used in the case of an incineration facility having a power generation facility, and a fuel combustion melting furnace is used in the case where there is no power generation facility or when performing wide-area treatment.
[0006]
A typical example of the fuel combustion melting furnace is a surface melting furnace. That is, the surface melting furnace is supplied with incineration ash and incineration fly ash from four directions in the furnace to form an inclined melting surface, or incineration ash and incineration fly ash from the facing two directions in the furnace. It has a face-to-face structure that forms an inclined melting surface that is supplied, and incineration ash and incineration fly ash collected in a hopper around the melting furnace are pushed into the furnace by an ash supply device and preheated on the furnace ceiling The surface of the incineration ash and incineration fly ash extruded by the combustion heat of the burner using air as the supporting gas is melted. This surface melting furnace has advantages such as being suitable for melting materials to be melted with non-uniform particle sizes including coarse materials such as incineration ash, and being able to use various fossil fuels with a simple structure. is doing.
[0007]
[Problems to be solved by the invention]
By the way, when incineration ash and incineration fly ash are mixed and melted in a fuel combustion type melting furnace such as a surface melting furnace, there are the following problems (1) to (5).
(1) Slaked lime Ca (OH) for acid gas treatment ₂ Since the incinerated fly ash into which the incineration is blown has a high basicity and a high melting point, the mixed ash of the incinerated fly ash and the incinerated ash necessarily has a high melting point. Therefore, in order to melt the high melting point mixed ash, it is necessary to keep the furnace temperature high. However, in the conventional fuel combustion melting furnace, the fuel ratio becomes high in order to make the furnace temperature sufficiently high. There's a problem.
(2) The conventional fuel combustion type melting furnace using a burner using normal air as a supporting gas has a problem that the amount of exhaust gas is large, resulting in an increase in the size and cost of the exhaust gas treatment facility.
(3) Incinerated fly ash contains a lot of volatile components such as heavy metals and is granular, so there are many incinerated fly ash that is taken out together with the exhaust gas without melting, and the concentration of dust contained in the exhaust gas is high. Therefore, there is a possibility that the ducts and the like are blocked, and that the slag rate is lowered.
(4) In order to melt incineration ash and incineration fly ash using a conventional fuel combustion melting furnace, a mixer for uniformly mixing incineration ash and incineration fly ash, or a mixer for incineration ash and incineration fly ash However, there is a problem in that a conveyor or the like to be transported is required, resulting in an increase in installation space and an increase in equipment cost.
(5) In a conventional fuel combustion type melting furnace, a certain amount of mixed ash is stored in a hopper so as to ensure a sealing property between the inside and outside of the furnace. However, incinerated fly ash has high hygroscopicity and low fluidity, so that it may cause a bridge in the hopper and not be supplied smoothly and smoothly into the furnace. Incinerated fly ash may cause problems in the operation of a fuel combustion melting furnace, such as causing flushing due to its high jet property.
[0008]
The present invention has been made in view of such problems, and its purpose is to stably melt incineration ash and incineration fly ash generated when incineration of waste in an incinerator at a low fuel ratio. An object of the present invention is to provide an oxygen burner type melting furnace which can be made.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 of the present invention is a high-temperature combustion generated in an incineration fly ash melting chamber in communication with an incineration fly ash melting chamber having a circular cross section and an incineration fly ash melting chamber. In a refractory structure melting furnace body with an incineration ash melting chamber into which exhaust gas flows, and a ceiling wall of the incineration fly ash melting chamber of the melting furnace body in a downward posture Primary oxygen is provided as a combustion support gas in the wind box, and secondary oxygen is supplied in a swirling state from a secondary oxygen nozzle provided in the melting furnace body to the incineration fly ash melting chamber below the wind box. Ru An oxygen burner melting furnace equipped with an oxygen burner that melts incineration fly ash and incineration ash generated by incineration of waste, and transports the incineration fly ash into the high-temperature flame of the oxygen burner. Combustion and melting in the incineration fly ash melting chamber, and supply incineration ash to the incineration ash melting chamber to contact the high-temperature combustion exhaust gas flowing from the incineration fly ash melting chamber into the incineration ash melting chamber, and incineration in the incineration ash melting chamber Ashes were melted by heating from the surface side. In the oxygen burner type melting furnace, into the incineration ash melting chamber on the ceiling wall of the incineration ash melting chamber of the melting furnace body An oxygen blowing nozzle for injecting tertiary oxygen is provided, and the amount of oxygen in the incineration fly ash melting chamber is made smaller than the amount of oxygen necessary for combustion of the oxygen burner fuel to make the incineration fly ash melting chamber a reducing atmosphere and incineration ash Tertiary oxygen is blown from the oxygen blowing nozzle into the melting chamber, and unburned gas in the combustion exhaust gas sent from the incineration fly ash melting chamber to the incineration ash melting chamber is completely burned by tertiary oxygen in the incineration ash melting chamber. This is the basic configuration of the invention.
[0010]
The invention according to claim 2 is the gas transport medium according to claim 1, wherein the incinerated fly ash is gas transported into the high-temperature flame of an oxygen burner. The , Supplied to oxygen burner as combustion support gas Primary oxygen It is what.
[0011]
The invention according to claim 3 is the structure according to claim 1, wherein the oxygen burner is capable of supplying oxygen, which is a combustion support gas, into the incineration fly ash melting chamber divided into primary oxygen and secondary oxygen in two stages. As a gas transport medium for incineration fly ash The While swirling, it can be blown into the high-temperature flame of an oxygen burner and secondary oxygen Formed on the ceiling wall of the incineration fly ash melting chamber It is designed to be blown into the incineration fly ash melting chamber while swirling from the secondary oxygen nozzle.
[0012]
According to a fourth aspect of the present invention, in the first aspect of the present invention, there is provided a hot water reservoir portion for accumulating molten slag at the bottom of the incineration fly ash melting chamber of the melting furnace main body, and the molten slag accumulated in the hot water reservoir portion of the melting furnace main body. The hot water flue gas in the incineration fly ash melting chamber is connected to the incineration fly ash melting chamber and the incineration ash melting chamber, which are provided at a position opposite to the tap outlet, while overflowing from the tap outlet formed at the bottom of the side wall. It is made to discharge from the exhaust gas outlet.
[0013]
The invention of claim 5 of the present invention is provided with an ash extrusion device for pushing incineration ash into the incineration ash melting chamber in the melting furnace main body, and the incineration ash is opposed to the flow of combustion exhaust gas in the incineration ash melting chamber by the ash extrusion device. It was pushed so as to form an angle of repose on the exhaust gas outlet side and brought into contact with the combustion exhaust gas in the incineration ash melting chamber, heated and melted from the surface side, and the molten slag of the molten incineration ash was allowed to flow down to the hot water reservoir There are features.
[0014]
In the invention of claim 6 of the present invention, an oxygen blowing nozzle for blowing tertiary oxygen into the incineration ash melting chamber is provided on the ceiling wall of the incineration ash melting chamber of the melting furnace main body, and the amount of oxygen in the incineration fly ash melting chamber is controlled by an oxygen burner. The amount of oxygen required for fuel combustion is reduced to make the incineration fly ash melting chamber a reducing atmosphere, and tertiary oxygen is blown from the oxygen blowing nozzle into the incineration ash melting chamber, and then the incineration ash melting chamber is injected from the incineration fly ash melting chamber. This is characterized in that the unburned gas in the combustion exhaust gas sent to the tank is completely burned with tertiary oxygen in the incineration ash melting chamber.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a flow diagram of an oxygen burner melting furnace 1 according to an embodiment of the present invention. The oxygen burner melting furnace 1 has a fireproof ash melting chamber 2 and an incineration ash melting chamber 3. A melting furnace body 4 having a physical structure, an oxygen burner 5 provided in the melting furnace body 4, oxygen (primary oxygen A1, secondary oxygen A2) and incineration fly ash D are supplied to the oxygen burner 5 connected to the oxygen burner 5 From the oxygen fly ash supply mechanism 6 that performs the operation, the incineration fly ash supply apparatus 7 that supplies the incineration fly ash D to the oxygen fly ash supply mechanism 6, and the incineration ash supply apparatus 8 that supplies the incineration ash D ′ to the melting furnace body 4 The incinerated fly ash D having a high melting point is configured to be gas transported into the high-temperature flame of the oxygen burner 5 by oxygen (primary oxygen A1) as a combustion gas of the oxygen burner 5 and burned in the incinerated fly ash melting chamber 2 While melting, the relatively low melting point incineration ash D ′ is supplied to the incineration ash melting chamber 3. The combustion exhaust gas G of high temperature flowing into the ash melting chamber 3 from 却飛 ash melting chamber 2 is obtained so as to heat and melt the surface.
[0016]
As shown in FIG. 1, the melting furnace body 4 is similar to the incineration fly ash melting chamber 2 having a circular cross section formed by a side wall 4a, a ceiling wall 4b and a furnace bottom 4c made of a metal casing and a refractory. An incineration ash melting chamber 3 and an incineration fly ash melting chamber 2 which are formed by a side wall 4a ′, a ceiling wall 4b ′ and a furnace bottom 4c ′ made of a metal casing and a refractory and communicate with the incineration fly ash melting chamber 2 are formed. Formed at the bottom of the side wall 4a, for pouring the molten slag S, S ', and at the bottom of the side wall 4a opposite to the tapping port 4d, the incineration fly ash melting chamber 2 An exhaust gas outlet 4f that communicates with the incineration ash melting chamber 3 and leads the combustion exhaust gas G in the incineration fly ash melting chamber 2 to the incineration ash melting chamber 3, and an exhaust gas outlet 4f below the side wall 4a 'that forms the incineration ash melting chamber 3 In the incinerated ash melting chamber 3 And ash supply port 4g supplies ash D ', is composed of a gas discharge port 4h for discharging the combustion exhaust gas G of incinerated ash melting chamber 3.
The furnace bottom 4c of the incineration fly ash melting chamber 2 is formed with a hollow hot water reservoir 4i for storing the molten slag S of the incineration fly ash D and the molten slag S 'of the incineration ash D'. The molten slags S and S 'accumulated in the portion 4i overflow from the tap outlet 4d and are discharged.
Further, an oxygen blowing nozzle 9 for blowing tertiary oxygen A3 into the incineration ash melting chamber 3 is provided on the ceiling wall 4 b ′ of the incineration ash melting chamber 3 of the melting furnace body 4. This oxygen blowing nozzle 9 is used for the combustion exhaust gas G when the oxygen blowing amount into the oxygen burner 5 is made smaller than the oxygen amount necessary for the combustion of the fuel F and the inside of the incineration fly ash melting chamber 2 is made a reducing atmosphere. In order to completely burn the unburned gas contained therein and to keep the temperature in the incineration ash melting chamber 3 at a high temperature, an oxygen supply source is provided via the tertiary oxygen supply pipe 10, the control valve 26 and the flow meter 27. 11 is connected. In this case, the inside of the incineration fly ash melting chamber 2 can be made a reducing atmosphere, and the combustion exhaust gas G can be reduced in NOx.
[0017]
In the melting furnace main body 4, an incineration ash hopper 12 for storing a certain amount of incineration ash D ′ and an ash extrusion device 13 for pushing the incineration ash D ′ in the incineration ash hopper 12 into the incineration ash melting chamber 3. Are provided.
[0018]
That is, the incineration ash hopper 12 is provided on the outer surface of the side wall 4a ′ forming the incineration ash melting chamber 3, and communicates with the incineration ash supply port 4g. The incineration ash hopper 12 constitutes a part of the incineration ash supply device 8 described later.
[0019]
On the other hand, the ash extrusion device 13 is provided at a lower position of the incineration ash hopper 12, and is arranged in parallel at a lower position of the incineration ash hopper 12, so that the incineration ash D ′ is infused from the incineration ash supply port 4g into the incineration ash melting chamber. 3 includes a plurality of pushers 13a that are pushed into 3 and a fluid pressure cylinder 13b that moves the pushers 13a forward and backward.
The ash extruding device 13 has the incineration ash D ′ stored in the incineration ash hopper 12 facing the flow of the combustion exhaust gas G in the incineration ash melting chamber 3 and rests on the furnace bottom 4 c ′ of the incineration ash melting chamber 3. The incineration ash supply port 4g is pushed toward the exhaust gas outlet 4f so as to form a corner. As a result, an incineration ash D ′ layer is formed on the furnace bottom 4c ′ of the incineration ash melting chamber 3 in a state where the surface is an inclined surface that gradually decreases from the incineration ash supply port 4g side toward the exhaust gas outlet 4f side. It will be different. The inclined surface of the incineration ash D ′ layer is an angle of repose of the incineration ash D ′.
[0020]
In FIG. 1, 14 is a molten slag dropping chute having a refractory structure connected to the outlet 4d of the melting furnace body 4, and 15 is disposed below the outlet 4d of the melting furnace body 4. A slag cooling water tank 16 is a water-sealed slag conveyor disposed in the slag cooling water tank.
[0021]
The oxygen burner 5 is provided in a downward posture at the center of the ceiling wall 4b of the incineration fly ash melting chamber 2 of the melting furnace body 4, and is a combustion supporting gas supplied by an oxygen fly ash supply mechanism 6 described later. Oxygen can be supplied into the incineration fly ash melting chamber 2 in two stages by dividing it into primary oxygen A1 and secondary oxygen A2, and the incineration fly ash D gas-transported by the primary oxygen A1, which is a gas transport medium, together with the primary oxygen A1 It is structured to be blown into the incineration fly ash melting chamber 2. In other words, the oxygen burner 5 blows the primary oxygen A1 together with the incineration fly ash D from the center of the oxygen burner 5 into the high-temperature flame of the oxygen burner 5 and the secondary oxygen A2 into the melting furnace body 4. It is configured to be blown into the incineration fly ash melting chamber 2 while being swung from the formed secondary oxygen nozzle 23.
[0022]
Specifically, as shown in FIG. 2, the oxygen burner 5 is disposed at the center of the burner throat 17 and the burner tile 18 formed at the center of the ceiling wall 4b of the incineration fly ash melting chamber 2, and the burner throat 17. A burner gun 19 provided with a nozzle 19a for blowing fuel F (liquid fuel such as kerosene or gaseous fuel such as natural gas) into the incineration fly ash melting chamber 2 at the tip, and a fuel supply pipe 20 connected to the burner gun 19, The spray medium supply pipe 21 connected to the burner gun 19 (not required when the fuel F is gaseous fuel) and the burner throat 17 are connected in communication to supply the primary oxygen A1 and the incineration fly ash D to the burner throat 17. The wind box 22 and the ceiling wall 4b (or the side wall 4c) are provided with a plurality of secondary oxygen nozzles 23 and the like for blowing secondary oxygen A2 into the incineration fly ash melting chamber 2. -While blowing primary oxygen A1 and secondary oxygen A2 from the throat throat 17 and the secondary oxygen nozzle 23 into the incineration fly ash melting chamber 2, the fuel F is blown from the burner gun 19 into the incineration fly ash melting chamber 2, and these are pilot burners, etc. By igniting and burning with an igniter (not shown), a downward high-temperature flame can be formed in the incineration fly ash melting chamber 2.
Further, a primary oxygen supply pipe 24 of an oxygen fly ash supply mechanism 6 to be described later is connected to the wind box 22 of the oxygen burner 5 in a tangential direction, and the primary oxygen A1 and incineration fly ash supplied into the wind box 22 are connected. D is blown into the incineration fly ash melting chamber 2 from the burner throat 17 while turning.
Further, the secondary oxygen nozzle 23 of the oxygen burner 5 is arranged so that the secondary oxygen A2 blown into the incineration fly ash melting chamber 2 swirls in the same direction as the primary oxygen A1. Or it is provided in several places of the side wall 4a), and the secondary oxygen A2 is blown into the incineration fly ash melting chamber 2 so that a swirl flow can be formed in the incineration fly ash melting chamber 2. The secondary oxygen nozzle 23 is connected to a secondary oxygen supply pipe 25 of the oxygen fly ash supply mechanism 6 described later.
[0023]
Thus, according to the oxygen burner 5, the primary oxygen A1 and the incineration fly ash D supplied from the primary oxygen supply pipe 24 into the wind box 22 are swirled in the wind box 22, and the burner is swung. It is blown from the throat 17 into the high temperature flame of the oxygen burner 5. The secondary oxygen A2 supplied from the secondary oxygen supply pipe 25 to the secondary oxygen nozzle 23 is swung in the same direction as the primary oxygen A1 from the secondary oxygen nozzle 23 and enters the incineration fly ash melting chamber 2. Infused.
[0024]
In the oxygen burner 5, when liquid fuel is used as the fuel F, steam, oxygen, and compressed air can be used as the spray medium H, but the amount of NOx generated is steam <oxygen <compressed air. Therefore, the use of steam as the spray medium H is desired in consideration of the suppression of NOx.
[0025]
The oxygen fly ash supply mechanism 6 supplies primary oxygen A1 and secondary oxygen A2 as supporting gases to the oxygen burner 5 and supplies incinerated fly ash D to the oxygen burner 5 by gas transport. As shown in FIG. 2, a secondary oxygen supply connected to a wind box 22 of the oxygen burner 5, a primary oxygen supply pipe 24 for supplying primary oxygen A 1 and incineration fly ash D to the wind box 22, and a secondary oxygen nozzle 23. A pipe 25, an oxygen supply source 11 connected to the primary oxygen supply pipe 24 and the secondary oxygen supply pipe 25, a control valve 26 and a flow meter interposed in the primary oxygen supply pipe 24 and the secondary oxygen supply pipe 25, respectively. 27 etc.
[0026]
The incineration fly ash supply device 7 has a fly ash silo 28 for storing the incineration fly ash D collected by the exhaust gas treatment facility of the incinerator, and a fly ash quantitative amount for cutting out the incineration fly ash D in the fly ash silo 28. A cutting device 29, a fly ash supply conveyor 30 for conveying the cut out incineration fly ash D, a fly ash weighing machine 31 for weighing the incineration fly ash D, and a weighing for discharging the incineration fly ash D in the fly ash measurement machine 31 A machine discharger 32, a hopper 33 for storing the incineration fly ash D discharged from the weighing machine discharger 32, a hopper quantitative cutout device 34 for cutting out the incineration fly ash D in the hopper 33 into the primary oxygen supply pipe 24, It comprises a hopper level sensor 35 that detects the amount of incinerated fly ash D stored in the hopper 33, a fly ash quantitative cutting device 29, a fly ash supply conveyor 30, a control device 36 that controls the weighing machine discharge device 32, and the like. Baked in the hopper 33 Fly ash D cut by hopper quantitative cutout device 34 by quantitative and supplies the primary oxygen supply pipe 24. The incineration fly ash D cut out in the primary oxygen supply pipe 24 is gas-transported by the primary oxygen A1 supplied from the oxygen supply source 11, and is supplied to the oxygen burner 5 together with the primary oxygen A1.
The incineration fly ash supply device 7 is driven and controlled by the control device 36 so that the incineration fly ash D is supplied into the hopper 33 at any time so that the level of the incineration fly ash D in the hopper 33 becomes constant. That is, when the control device 36 receives a signal indicating that the level of the incineration fly ash D in the hopper 33 has decreased from the hopper level sensor 35, the fly ash metering device 29 until the fly ash meter 31 detects the set weight. Then, when the fly ash supply conveyor 30 is operated and the fly ash meter 31 detects the set weight, the fly ash quantitative cutting device 29 and the fly ash supply conveyor 30 are sequentially stopped, and then the meter discharge device 32 is turned on. The incineration fly ash D is operated and supplied to the hopper 33.
[0027]
The incineration ash supply device 8 includes an incineration ash silo 37 for storing the incineration ash D ′ discharged from the incinerator, an incineration ash quantitative extraction device 38 for cutting out the incineration ash D ′ in the incineration ash silo 37, and incineration. The incineration ash measuring machine 39 for measuring the fly ash D, the weighing machine discharge device 40 for discharging the incineration ash D ′ in the incineration ash measurement machine 39, and the incineration ash D ′ discharged from the weighing machine discharge device 40 are conveyed. Incineration ash supply conveyor 41, incineration ash hopper 12 for storing incineration ash D ', hopper level sensor 42 for detecting the amount of incineration ash D' stored in incineration ash hopper 12, incineration ash quantitative cutting device 38, weighing It comprises a control device 43 for controlling the machine discharge device 40 and the incineration ash supply conveyor 41 and the like.
Further, the incineration ash supply device 8 is driven and controlled by the control device 43 so that the incineration ash D ′ is supplied into the incineration ash hopper 12 at any time so that the level of the incineration ash D ′ in the incineration ash hopper 12 becomes constant. Yes. That is, when the control device 43 receives a signal indicating that the level of the incineration ash D ′ in the incineration ash hopper 12 has decreased from the hopper level sensor 42, the control device 43 extracts the incineration ash quantitatively until the incineration ash meter 39 detects the set weight. When the apparatus 38 is operated and the incinerated ash metering machine 39 detects the set weight, the incinerated ash metering device 38 is stopped, and then the weighing machine discharge device 40 and the incinerated ash supply conveyor 41 are operated to incinerate the incineration ash. D ′ is supplied to the incineration ash hopper 12.
[0028]
Next, the case where the incineration ash D ′ discharged from the incinerator and the incineration fly ash D collected by the exhaust gas treatment facility of each incinerator are melt-processed using the above-described oxygen burner melting furnace 1 will be described. .
At the start of melting of the incineration fly ash D and the incineration ash D ′, the oxygen burner 5 and the like are operated in advance to set the temperatures of the incineration fly ash melting chamber 2 and the incineration ash melting chamber 3 of the melting furnace body 4 to predetermined temperatures (incineration fly The ash D and the incinerated ash D ′ are preheated to a temperature capable of melting.
[0029]
When the incineration fly ash melting chamber 2 and the incineration ash melting chamber 3 of the melting furnace body 4 reach a predetermined temperature, the incineration fly ash D and the primary oxygen A1 are combined with the incineration fly ash supply device 7 and the oxygen fly ash supply mechanism 6. To the oxygen burner 5. That is, the incineration fly ash D put into the fly ash silo 28 is a fly ash quantitative cutout device 29, a fly ash supply conveyor 30, a fly ash meter 31, a meter discharger 32, a hopper 33, and a hopper quantitative cutout device 34. Are sequentially supplied to the primary oxygen supply pipe 24, are transported in gas by the primary oxygen A1 flowing in the primary oxygen supply pipe 24, and are supplied into the wind box 22 together with the primary oxygen A1.
[0030]
The primary oxygen A1 and the incineration fly ash D supplied into the wind box 22 are swirled and blown into the incineration fly ash melting chamber 2 from the burner throat 17 and burned and melted in the high temperature flame of the oxygen burner 5. It becomes the molten slag S. At this time, since the oxygen burner 5 uses oxygen as the combustion support gas, a high-temperature flame can be obtained as compared with a conventional burner using air as the combustion support gas. As a result, even the high melting point incineration fly ash D can be reliably burned and melted alone. In addition, since the incineration fly ash D is gas-transported into the high-temperature flame by the primary oxygen A1 that is the combustion support gas, the surface area of each fly ash particle can be fully utilized as the heat receiving surface, and the incineration fly ash D can be efficiently melted.
[0031]
The molten slag S adheres to the inner surface of the side wall 4a of the melting furnace body 4 by the swirling flow of the combustion exhaust gas G generated by swirling the primary oxygen A1 and the secondary oxygen A2 while swirling into the incineration fly ash melting chamber 2. It flows to the 4c side. At this time, a coating layer of the molten slag S is formed on the inner surface of the side wall 4a by the molten slag S adhering to the inner surface of the side wall 4a of the melting furnace body 4. Thereby, the surface of the refractory forming the side wall 4 a can be protected from the high temperature flame of the oxygen burner 5.
[0032]
The molten slag S that has flowed to the furnace bottom 4c side is temporarily stored in the hot water reservoir 4i formed in the furnace bottom 4c, and then overflows sequentially from the tap 4d to flow through the bowl 4e. It falls into the slag cooling water tank 15, is rapidly cooled and solidified by the cooling water, becomes granular granulated slag, and is carried out by the water-sealed slag conveyor 16. At this time, since the molten slag S is temporarily stored in the hot water pool portion 4i formed on the furnace bottom 4c of the melting furnace body 4, the surface of the refractory forming the furnace bottom 4c is set at a high temperature of the oxygen burner 5. Can be protected from flames. Further, since the molten slag S is accumulated in the hot water reservoir 4i of the furnace bottom 4c, the residence time of the molten slag S in the furnace becomes longer, and the content of heavy metals in the molten slag S is reduced. The unmelted material in the combustion exhaust gas G falls into the hot water reservoir 4i and is completely melted.
[0033]
On the other hand, the high-temperature combustion exhaust gas G generated in the incineration fly ash melting chamber 2 is sent into the incineration ash melting chamber 3 through the exhaust gas outlet 4f. At this time, incineration ash D ′ is supplied into the incineration ash melting chamber 3 by the incineration ash supply device 8 and the ash extrusion device 13. That is, the incineration ash D ′ charged into the incineration ash silo 37 passes through the incineration ash quantitative cutting device 38, the incineration ash metering device 39, the weighing machine discharge device 40 and the incineration ash supply conveyor 41 in order into the incineration ash hopper 12. Supplied and stored here. The incineration ash D ′ stored in the incineration ash hopper 12 is successively pushed into the incineration ash melting chamber 3 sequentially from the incineration ash supply port 4g by the pusher 13a of the ash extrusion device 13, and the surface is in turn from the incineration ash supply port 4g side. It is deposited on the furnace bottom 4c ′ of the incineration ash melting chamber 3 in a state where the inclined surface gradually becomes lower toward the exhaust gas outlet 4f. The angle of the inclined surface of the incinerated ash D ′ layer is the angle of repose of the incinerated ash D ′.
[0034]
The high-temperature combustion exhaust gas G flowing into the incineration ash melting chamber 3 flows along the surface of the incineration ash D ′ layer formed on the furnace bottom 4 c ′ of the incineration ash melting chamber 3, and the incineration ash D ′ layer Are sequentially heated from the surface side and discharged from the exhaust gas outlet 4h. Thereby, the incineration ash D ′ layer formed on the furnace bottom 4c ′ is heated by the high-temperature combustion exhaust gas G flowing in the incineration ash melting chamber 3 from the exhaust gas outlet 4f side to the exhaust gas outlet 4h side, Are sequentially melted to form a film-like molten slag S ′. The molten slag S ′ flows down the inclined surface of the incinerated ash D ′ layer and flows from the exhaust gas outlet 4f into the hot water reservoir 4i formed in the furnace bottom 4c of the incinerated fly ash melting chamber 2, and in the hot water reservoir 4i. After being mixed with the molten slag S of the incineration fly ash D and temporarily stored, it sequentially overflows from the outlet 4d and flows into the slag cooling water tank 15 below the outlet 4e. It is rapidly cooled and solidified to form granular granulated slag, which is carried out by a water-sealed slag conveyor 16.
[0035]
Further, the combustion exhaust gas G discharged from the exhaust gas discharge port 4h is sent to a temperature reducing tower (not shown), where the temperature is reduced by injection of a cooling medium such as cooling water, and then a dust collector or a catalyst denitration tower. After passing through an exhaust gas treatment facility (not shown) such as a clean gas, it is discharged into the atmosphere from a chimney (not shown).
[0036]
Further, in the incineration ash melting chamber 3, tertiary oxygen A <b> 3 is blown into the incineration ash melting chamber 3 from an oxygen blowing nozzle 9 provided on the ceiling wall 4 b ′ of the incineration ash melting chamber 3. Thereby, the combustion exhaust gas G in the incineration ash melting chamber 3 is subjected to secondary combustion in the incineration ash melting chamber 3 by the tertiary oxygen A3. Therefore, in order to reduce NOx in the combustion exhaust gas G, the total amount of primary oxygen A1 and secondary oxygen A2 injected into the oxygen burner 5 is made smaller than the amount of oxygen required for the combustion of the fuel F, and incineration fly ash is melted. When the inside of the chamber 2 is in a reducing atmosphere, the unburned gas contained in the combustion exhaust gas G can be completely burned, and the temperature in the incineration ash melting chamber 3 can be maintained at a high temperature so that the incineration ash D ′ Can be satisfactorily heated and melted.
In this oxygen burner type melting furnace 1, the total amount of primary oxygen A1 and secondary oxygen A2 and the distribution ratio of tertiary oxygen A3 are changed according to the treatment ratio of incineration fly ash D and incineration ash D ′. The combustion ratio in the fly ash melting chamber 2 and the incineration ash melting chamber 3 is adjusted.
[0037]
【The invention's effect】
As is clear from the above description, the oxygen burner melting furnace of the present invention can achieve the following effects.
(1) An incinerator fly ash melting chamber and an incinerator ash melting chamber communicating with the incinerator ash melting chamber are provided with an oxygen burner, and the high melting point incineration fly ash is gas transported into the high-temperature flame of the oxygen burner for incineration fly ash melting. In addition to melting in the room, the incineration ash with a relatively low melting point is supplied to the incineration ash melting chamber and heated and melted by the high-temperature combustion exhaust gas flowing from the incineration fly ash melting chamber into the incineration ash melting chamber. The amount of heat can be effectively used, and the fuel ratio can be reduced.
(2) Since the incineration fly ash is gas transported into the high-temperature flame by oxygen as the combustion-supporting gas, the surface area of each fly ash particle can be fully utilized as the heat receiving surface, and the incineration fly ash is efficient. It becomes possible to melt well.
(3) Since an oxygen burner is used, the amount of exhaust gas can be reduced. As a result, the amount of heat taken out of the exhaust gas can be reduced, the fuel ratio can be reduced, the melting furnace body and the exhaust gas treatment facility can be made compact, and the installation space and equipment cost can be reduced.
(4) Oxygen, which is the combustion gas of the oxygen burner, is supplied into the incineration fly ash melting chamber divided into primary oxygen and secondary oxygen in two stages, and blown into the incineration fly ash melting chamber while swirling the primary and secondary oxygen. Therefore, the molten slag adheres to the inner surface of the side wall of the melting furnace main body due to the swirling flow of the combustion exhaust gas generated by the primary oxygen and the secondary oxygen blown into the incineration fly ash melting chamber, and moves toward the bottom of the furnace. It flows. As a result, the surface of the refractory forming the side wall can be protected from the high temperature flame of the oxygen burner by the molten slag adhering to the inner surface of the side wall of the melting furnace body.
(5) Incineration fly ash is instantly melted in a high-temperature flame of an oxygen burner, and a part of the incineration fly ash adheres to the molten slag flowing down the inner wall of the incineration fly ash melting chamber and is melted. Therefore, it is possible to reduce unmelted ash discharged together with the combustion exhaust gas.
(6) An incineration fly ash melting slag and an incineration ash molten slag are provided at the bottom of the incinerator fly ash melting chamber of the melting furnace body to temporarily store the molten slag that has accumulated in the hot pool. Since the hot water is discharged from the tap, the surface of the refractory forming the furnace bottom can be protected from the high-temperature flame of the oxygen burner by the molten slag temporarily stored in the hot water reservoir.
(7) Since the molten iron slag for incineration fly ash and the molten slag for incineration ash are temporarily stored at the bottom of the incineration fly ash melting chamber of the melting furnace body, the molten slag has sufficient residence time Can be completely melted by being placed in a high temperature environment, and the content of heavy metals in the molten slag can be reduced.
(8) An oxygen blowing nozzle that blows tertiary oxygen into the incineration ash melting chamber is provided on the ceiling wall of the incineration ash melting chamber, and the unburned gas in the combustion exhaust gas sent from the incineration fly ash melting chamber into the incineration ash melting chamber is incinerated. Because it burns with tertiary oxygen in the ash melting chamber, unburned gas in the combustion exhaust gas can be completely burned, and oxygen in the oxygen burner is reduced to reduce the incineration fly ash melting chamber. The atmosphere can be made, and NOx reduction of combustion exhaust gas can be achieved. However, the content of heavy metals in the molten slag can be reduced by melting the incinerated fly ash in a high-temperature flame and in a reducing atmosphere.
(9) Since the incineration fly ash is separately supplied into the incineration fly ash melting chamber of the melting furnace main body and the incineration ash is separately supplied into the incineration ash melting chamber of the melting furnace main body, In this way, there is no need for a mixer to uniformly mix incineration ash and incineration fly ash, or a conveyor to transport the incineration ash and incineration fly ash to the mixer. Cost can be reduced.
(10) Since primary oxygen and secondary oxygen are blown into the incineration fly ash melting chamber and tertiary oxygen is blown into the incineration ash melting chamber, distribution of oxygen blown into the incineration fly ash melting chamber and incineration ash melting chamber By adjusting the amount, it is possible to perform operation in accordance with the treatment ratio of incineration fly ash and incineration ash.
[Brief description of the drawings]
FIG. 1 is a flow diagram of an oxygen burner type melting furnace according to an embodiment of the present invention.
FIG. 2 is a schematic longitudinal sectional view of an oxygen burner used in an oxygen burner melting furnace.
[Brief description of symbols]
1 is an oxygen burner melting furnace, 2 is an incineration fly ash melting chamber, 3 is an incineration ash melting chamber, 4 is a melting furnace body, 4b and 4b 'are ceiling walls, 4c and 4c' are furnace bottoms, and 4d is an outlet 4f is an exhaust gas outlet, 4i is a hot water reservoir, 5 is an oxygen burner, 9 is an oxygen blowing nozzle, 13 is an ash extrusion device, 23 is a secondary oxygen nozzle, A1 is primary oxygen, A2 is secondary oxygen, and A3 is Tertiary oxygen, D is incineration fly ash, D 'is incineration ash, G is combustion exhaust gas, and S and S' are molten slag.

Claims (5)

A refractory structure melting furnace body having an incineration ash melting chamber in which a high-temperature combustion exhaust gas generated in the incineration fly ash melting chamber flows in communication with the incineration fly ash melting chamber having a circular cross-sectional shape and the incineration fly ash melting chamber; In the incineration fly ash melting chamber of the melting furnace main body, it is installed in a downward posture, primary oxygen as a combustion support gas into the wind box, and secondary oxygen from a secondary oxygen nozzle provided in the melting furnace main body An oxygen burner melting furnace equipped with an oxygen burner that is supplied in a swirling state into the incineration fly ash melting chamber below the wind box and that melts incineration fly ash and incineration ash generated by incineration of waste. The incineration fly ash is gas transported into the high-temperature flame of the oxygen burner and burned and melted in the incineration fly ash melting chamber, and the incineration ash is supplied into the incineration ash melting chamber to melt the incineration ash from the incineration fly ash melting chamber. Hot fuel flowing into the chamber In an oxygen burner melting furnace that is brought into contact with exhaust gas and heat-melts the incineration ash in the incineration ash melting chamber from the surface side, tertiary oxygen is introduced into the incineration ash melting chamber on the ceiling wall of the incineration ash melting chamber of the melting furnace body. An oxygen blowing nozzle is provided to reduce the amount of oxygen in the incineration fly ash melting chamber to less than the amount of oxygen necessary for the combustion of the oxygen burner fuel to make the incineration fly ash melting chamber a reducing atmosphere, and in the incineration ash melting chamber The tertiary oxygen was blown from the oxygen blowing nozzle, and the unburned gas in the combustion exhaust gas sent from the incineration fly ash melting chamber to the incineration ash melting chamber was completely burned by the tertiary oxygen in the incineration ash melting chamber. Features an oxygen burner melting furnace. The oxygen burner melting furnace according to claim 1, wherein the gas transport medium for transporting the incinerated fly ash into the high-temperature flame of the oxygen burner is primary oxygen supplied to the oxygen burner as a combustion support gas. Oxygen burner, a structure capable of supplying two stages divided into primary oxygen and the secondary oxygen oxygen is the oxidizing gas to the incineration fly ash melting chamber, while turning it the primary oxygen as gaseous transport medium incineration fly ash It is configured to blow into the high-temperature flame of the oxygen burner and to blow secondary oxygen into the incineration fly ash melting chamber while swirling from the secondary oxygen nozzle formed on the ceiling wall of the incineration fly ash melting chamber. The oxygen burner melting furnace according to claim 1, wherein   A hot water reservoir for storing molten slag is provided at the bottom of the incinerator fly ash melting chamber of the melting furnace main body, and the molten slag accumulated in the hot water reservoir is overflowed from the outlet formed at the lower side of the side wall of the melting furnace main body and discharged. In addition, the high-temperature combustion exhaust gas in the incineration fly ash melting chamber is discharged from an exhaust gas outlet communicating the incineration fly ash melting chamber and the incineration ash melting chamber provided at a position facing the tap outlet. The oxygen burner type melting furnace according to claim 1.   An ash extrusion device that pushes incineration ash into the incineration ash melting chamber is installed in the melting furnace body, and the ash extrusion device forms an angle of repose on the exhaust gas outlet side facing the flow of combustion exhaust gas in the incineration ash melting chamber. 2. The oxygen according to claim 1, wherein the molten slag of the incinerated ash is pressed and melted from the surface side by contacting with the combustion exhaust gas in the incinerated ash melting chamber, and the molten slag of the molten incinerated ash is caused to flow down to the hot water pool portion. Burner type melting furnace.

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