JP3938980B2 - Waste gasification apparatus and furnace wall self-coating method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a furnace wall self-coating method in waste gasification treatment, and in particular, performs furnace wall self-coating of the high-temperature oxidation furnace in a two-stage gasification system using a fluidized bed gasification furnace and a high-temperature oxidation furnace. It is related to the method.
[0002]
[Prior art]
Organic waste represented by municipal waste, sewage sludge, waste plastic, waste FRP, biomass waste, automobile waste, waste oil, etc. is generally reduced by incineration or left untreated They are disposed of in landfills, and the amount that they are recycled is very small.
[0003]
In the above incineration treatment, stoker furnaces and fluidized bed furnaces have been used so far, but the amount of exhaust gas is large due to the high air ratio during combustion, and the metals discharged from the furnace are oxidized. Not suitable for recycling. Recently, the number of such incineration facilities with an ash melting facility is increasing, but this has resulted in an increase in the construction cost and operating cost of the entire system.
[0004]
Japanese Patent Laid-Open No. 7-332614 has been invented to solve these problems, in which organic waste is supplied to a fluidized bed furnace for gasification, valuable metals are taken out in an unoxidized state, and product gas is produced. By supplying slag to the subsequent melting combustion furnace and burning it completely at a high temperature, thereby converting the ash into molten slag, reducing the volume, making it stable slag that can be landfilled, extending the life of landfilled land, and recycling it as earthwork material Is presented. In the above method, combustible gas containing unburned char is generated from waste by the fluidized bed furnace in the previous stage, and supplied to the molten combustion furnace in the subsequent stage to completely burn at high temperature, thereby converting the ash into molten slag. In addition, we expect complete decomposition of dioxins.
[0005]
As described above, when the product gas of the fluidized bed gasification furnace is completely burned in the subsequent melt combustion furnace, the heat generated by the exhaust gas can be effectively utilized, but the product gas contains a large amount of combustible gas components. This can be recycled, for example, as a raw material for the chemical industry in the form of synthesis gas. This is the so-called chemical recycling concept.
[0006]
From such a viewpoint, primary gasification is performed at a relatively low temperature in a fluidized bed gasification furnace, and the obtained gaseous matter and unburned char are supplied to a high temperature oxidation furnace for secondary gasification, and H ₂ (hydrogen), By recovering synthesis gas mainly composed of CO (carbon monoxide), useful resources can be achieved. However, since the high-temperature oxidation furnace used for secondary gasification is used at a high temperature of 1200 to 1600 ° C., the furnace wall structure is generally from the outer surface side as shown in FIG. It has a structure in which an iron skin 1, a castable 2, a heat insulating brick 3, a fireproof heat insulating brick 4, and a fireproof brick 5 are laminated. In such a high-temperature oxidation furnace, when primary gas obtained by using organic waste as a raw material is supplied and secondary gasification is performed at a high temperature, a molten slag layer is formed on the inner wall surface of the furnace. However, the surface layer of the refractory brick 5 is eroded by the salts contained in the slag. Therefore, the refractory brick 5 in the high-temperature oxidation furnace is required to have not only heat resistance but also strong corrosion resistance.
[0007]
[Problems to be solved by the invention]
However, since it is difficult to find a brick suitable for a high-temperature oxidation furnace that obtains a secondary gas by gasifying a primary gas obtained by gasifying organic waste at a low temperature of 1200 to 1600 ° C., Even if a structure in which three layers of bricks were laminated in addition to the iron skin 1 and the castable 2 described above, the durability was not sufficient. Therefore, the furnace wall of the high-temperature oxidation furnace is cooled by adopting a boiler wall structure or a water-cooled jacket wall structure with a built-in water pipe, and the entire surface of the furnace is protected by coating it with a sufficient amount of molten slag. It is possible. However, organic waste such as plastic waste and biomass waste has little ash, so it is difficult to cover the entire interior of a high-temperature oxidation furnace with a molten slag coating. It was practically difficult to completely prevent this.
[0008]
In the present invention, when primary gasification by a fluidized bed gasification furnace and secondary gasification by a high temperature oxidation furnace are performed, in particular, it is possible to effectively protect the furnace wall of the high temperature oxidation furnace and increase its durability. It is an object of the present invention to provide a gasification treatment apparatus and a furnace wall self-coating method for waste.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a waste gasification treatment apparatus according to the present invention is obtained in a gasification furnace using a fluidized bed for primary gasification of organic waste and the fluidized bed gasification furnace. A high-temperature oxidation furnace for introducing a gaseous substance into a secondary gas at high temperature, and the furnace wall of the high-temperature oxidation furnace is a device having a boiler wall structure or a water-cooled jacket structure with a built-in water pipe. An ash circulation supply line for supplying a part of the slag or molten fly ash generated in the high-temperature oxidation furnace to a low-temperature gasification furnace, a high-temperature oxidation furnace, or a gaseous material path between both furnaces is provided. By being accompanied by the gaseous matter introduced, a deposited ash coating layer can always be formed on the furnace wall during secondary gasification. As another method, an ash replenishment line such as incinerated ash introduced from the outside is provided in the low temperature gasification furnace, the high temperature oxidation furnace or the gaseous substance path between the two furnaces, and the gaseous matter introduced into the high temperature oxidation furnace is provided. The amount of ash to be accompanied can also be maintained at a set value.
[0010]
The furnace wall self-coating method in the gasification treatment of waste according to the present invention is performed by supplying organic waste such as waste plastic, shredder dust, municipal waste, sewage sludge to a gasification furnace using a fluidized bed. Mainly H ₂ (hydrogen), CO (carbon monoxide) by gasifying and introducing the gaseous substance obtained in the fluidized bed gasification furnace into a high temperature oxidation furnace and secondary gasification at high temperature In the waste gasification method for recovering the gas, the amount of ash contained in the primary gas introduced into the high-temperature oxidation furnace becomes the set layer thickness of the deposited ash coating layer on the water-cooled wall of the high-temperature oxidation furnace The settings are adjusted as follows. The ash amount is set by supplying a part of the slag or molten fly ash generated in the high-temperature oxidation furnace to the low-temperature gasification furnace, the high-temperature oxidation furnace or the gaseous material path between the two furnaces, and introduced from the outside. Incinerated ash can also be supplied through an ash replenishment line. Further, it is desirable to adjust the particle size of the supply slag and supplemental ash in advance by pulverization.
[0011]
Furthermore, organic waste such as waste plastic, shredder dust, municipal waste, and sewage sludge is primary gasified by supplying it to a gasification furnace using a fluidized bed, and the resulting gaseous matter and unburned char are heated at a high temperature. In a waste gasification method for recovering H ₂ and CO-based gases by introducing into an oxidation furnace and secondary gasification at a high temperature, the waste gas is deposited on the inner surface of the water-cooled wall of the high-temperature oxidation furnace. The water cooling temperature is adjusted so that the solidified ash coating layer and the molten ash coating layer melted by the furnace temperature are formed on the top surface of the solidified ash coating layer, and the fireproof brick is protected by the solidified ash coating layer. I am doing so.
[0012]
[Action]
By bringing the organic waste and the oxygen-containing gas into contact with each other in a fluidized bed gasification furnace, primary gasification is performed by partial oxidation at a relatively low temperature (450 to 850 ° C.). The obtained high-calorie gaseous matter, unburned char and oxygen-containing gas are introduced into a high-temperature oxidation furnace, where secondary gasification is performed at a high temperature (1200 to 1600 ° C.). A gas mainly composed of H ₂ (hydrogen) and CO (carbon monoxide) can be generated.
[0013]
In the present invention, the furnace wall of the high-temperature oxidation furnace is cooled with a boiler wall structure or a water-cooled jacket wall structure with a built-in water pipe, and part of the slag or molten fly ash discharged from the high-temperature oxidation furnace is again converted into the high-temperature oxidation furnace. Since it is supplied and melted, a certain amount of ash accompanying the primary gas supplied to the high-temperature oxidation furnace can always be secured. A solidified ash coating layer is formed on the furnace wall by a cooling action by a water pipe or the like, and a molten ash coating layer melted by the temperature in the furnace is formed on the surface layer surface. Due to changes in the amount of heat and moisture due to changes in the composition of the waste supplied to the upstream fluidized bed gasification furnace, the temperature inside the high-temperature oxidation furnace becomes high, and the fluidity of the ash adhering to the furnace wall is increased. By increasing the thickness of the ash coating, the solidified coating layer can be left by the cooling action of the water pipe even when the thickness of the ash coating is reduced, which protects the refractory brick.
[0014]
In addition, when waste plastic, biomass waste, or the like is used as a raw material, it is difficult to actively form and maintain an ash coating layer on the furnace wall of the high-temperature oxidation furnace because of low ash content. In such a case, incineration ash, coal ash, or the like may be replenished so that an appropriate amount of ash is accompanied in the primary gas. The required amount of ash in the high-temperature oxidation furnace can be determined by the inner surface area of the furnace wall, the required layer thickness of the molten ash coating layer, and the flow rate of the molten slag. Therefore, the total amount of ash contained in the primary gas from the fluidized bed gasifier, the amount of slag discharged from the high-temperature oxidation furnace and circulated and the amount of supplemental ash supplied from the outside is set to be the required ash amount. do it. Circulating slag and supplemental ash need to be adjusted in advance to be pulverized and to have a particle size of a certain value or less before being introduced into the high-temperature oxidation furnace. If the particle size is coarse, the dispersion in the primary gas becomes non-uniform and quantitative supply cannot be performed. Therefore, the ash particle size is made fine to ensure the formation of the ash coating.
[0015]
In order to protect the furnace wall of the high-temperature oxidation furnace, it is necessary to form an ash coating layer having a constant thickness. However, the layer thickness can be adjusted by adjusting the amount of heat removed from the furnace wall. Therefore, when there is a risk of deterioration of the refractory bricks, it is possible to enhance the protection of the furnace wall by increasing the thickness of the solidified ash coating layer by lowering the cooling temperature. However, the temperature of the surface of the water-cooled part should be higher than the dew point of the product gas containing corrosive gas components such as H ₂ S (hydrogen sulfide) and HCl (hydrochloric acid) to prevent corrosion of the water pipe (furnace wall, iron skin). There is a need to.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of a waste gasification apparatus and a furnace wall self-coating method according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a flowchart of a waste gasification apparatus according to an embodiment.
The gasification treatment apparatus is a primary gasification at a relatively low temperature of 450 to 850 ° C. in a fluidized bed gasification furnace in the former stage, and a high temperature in the latter stage in a state accompanied by pulverized unburned char in the primary gas. By generating secondary gas at 1200 to 1600 ° C. in an oxidation furnace, synthesis gas mainly composed of H2 (SK hydrogen) and CO (carbon monoxide) is generated.
[0017]
First, the raw materials supplied to the gasification processing equipment include municipal waste, sewage sludge, solid fuel, slurry fuel, waste plastic, waste FRP, biomass waste, automobile waste, waste oil, and other organic waste, Bottom grade coal can be used. Organic waste is roughly crushed to about 30 mm and supplied, and solid fuel, slurry fuel and waste oil are supplied as they are. The low-grade coal is supplied after being crushed to about 40 mm. These are received by a pipe, sufficiently stirred and mixed, and then appropriately supplied to the fluidized bed gasification furnace 10. If the properties of the waste to be gasified (calorific value and moisture) are not good, coal, oil coke, etc. can be added as an auxiliary raw material if necessary. The amount to be added is appropriately determined depending on the properties of the waste. The organic waste 12 that has been crushed in advance in this way is supplied to the hopper, and then supplied to the fluidized bed gasification furnace 10 using the screw-type quantitative supply device 14.
[0018]
The fluidized bed gasification furnace 10 into which the waste is charged is composed of a lower fluidized bed portion 16 and an upper freeboard portion 18, both of which communicate with each other via a neck portion 20. The fluidized bed portion 16 is filled with sand (eg, dredged sand, olivine sand), alumina, iron powder, limestone, dolomite, etc. as a fluidized medium 24 on a dispersion plate 22 arranged at the bottom of the furnace. The fluidizing medium 24 is fluidized by ejecting a fluidizing gas into the layer of the fluidizing medium 24. The dispersion plate 22 is shaped like a conical cone protruding from the center, and the fluidizing gas is divided and supplied to the central portion and the peripheral portion of the dispersion plate 22. The flow rate of the fluidizing gas supplied to the central portion is reduced, and oxygen is diluted by recycling a part of the product gas at the outlet of the scrubber 56 described later. The flow rate of the fluidizing gas supplied to the peripheral part is increased, and similarly, the recycle gas is added to make the oxygen concentration the same as or higher than the central part. As a result, a swirling motion is generated in the fluidized bed so that the fluidized medium 24 becomes a downward flow at the central portion of the fluidized bed portion and an upward flow at the peripheral portion.
[0019]
Since the central part fluidized gas has a low oxygen concentration, the combustible gas with a large calorific value including tar generated in the fluidized bed formed as a downward flow in the central part of the fluidized bed is slightly close to dry distillation. After being pyrolyzed and gasified, the ascending to the free board portion 18. Char, which is a solid material generated in the central fluidized bed, is circulated and transferred to the fluidized bed in the peripheral part together with the fluidized medium, and partially combusts char by contacting with the peripheral fluidized gas having a relatively high oxygen concentration. Thus, CO and CO ₂ main gases are generated to generate heat that maintains the inside of the furnace at 450 to 850 ° C. Thus, gas, tar, and char are generated by primary gasification in the fluidized bed, but the rate of generation of tar and char increases and the rate of gas generation decreases as the temperature decreases. Since the entire interior of the gasifier is maintained in a reducing atmosphere, any metal contained in the waste that has a melting point higher than the fluidized bed temperature is discharged together with the fluid medium from the bottom of the gasifier as unoxidized valuable metal. Is done. Therefore, for example, aluminum can be recovered in an unoxidized metal state when the fluidized bed temperature is lower than 660 ° C., which is the melting point of aluminum. For this recovery, a discharge port 26 is provided in the periphery of the fluidized bed furnace. In this way, valuable metals such as iron, copper, and aluminum contained in the incombustible material can be recovered from the outlet 26 in a clean and unoxidized state. At the same time, the dredged sand of the fluid medium 24 discharged together with the incombustible material from the discharge port 26 is transported upward using a bucket conveyor or the like after separating the incombustible material by a dispensing operation and returned to the fluidized bed gasification furnace 10. .
[0020]
The organic waste thrown into the fluidized bed portion 16 of the gasification furnace 10 becomes gas, tar, and char by primary gasification, and the gas and tar are vaporized and rise in the furnace. The char is refined by the swirling motion of the fluid medium while undergoing partial oxidation. Since the refined char is porous and light, it is entrained in the upward flow of gas. By using hard cinnabar as the fluid medium 24, char crushing is further promoted. The gas, tar, and unburned char that have exited the fluidized bed gasification furnace 10 are supplied to a high-temperature oxidation furnace 30 in the next stage, and CO (carbon monoxide), H ₂ (hydrogen) by high-temperature secondary gasification here. ) The main synthesis gas is generated.
[0021]
The primary gas discharged from the top of the fluidized bed gasification furnace 10 is supplied to the next stage high temperature oxidation furnace 30 through the primary gas transfer path 32. A burner is attached to the top of the high-temperature oxidation furnace 30. By supplying the primary gas and oxygen gas as a gasifying agent separately into the furnace, partial oxidation is performed at a high temperature of 1200 to 1600 ° C. Secondary gasification is performed. A reaction chamber 34 lined with a refractory is formed in the upper half of the high temperature oxidation furnace 30. A quenching chamber 36 is provided at the lower part of the high-temperature oxidation furnace 30, and the reaction chamber 34 and the quenching chamber 36 are communicated with each other through a throat portion 38. A water line 40 for sending water for gas quenching is opened in the quenching chamber 36, and water is supplied and discharged so as to obtain an appropriate water level. The secondary gas generated in the reaction chamber 34 passes through the throat portion 38 and is blown into the water in the quenching chamber 36, and then the gas line 44 from the gas discharge port 42 provided in the upper region of the water surface of the quenching chamber 36. It is made to feed to the following scrubber 56 through.
[0022]
In this case, it is desirable to supply the primary gas to the high-temperature oxidation furnace 30 so as to make a swirl flow in the reaction chamber 34 so that the residence time of the unburned char becomes long. As a result, the unburned char descends while circling along the furnace wall, and is gasified at 1200 to 1600 ° C. at high speed while being mixed in the swirling flow with the gasifying agent by radiant heat from the combustion flame and the furnace wall. As a result of this secondary gasification, the ash contained in the unburned char becomes slag mist, is captured by the molten slag layer on the furnace wall of the reaction chamber 34 by the centrifugal force of the swirling flow, flows down the furnace wall, and enters the quenching chamber 36. It is crushed in the quenching chamber 36 to become slag particles, discharged to the outside through the lock hopper 46, and separated into coarse slag and fine slag by the screen 48.
[0023]
In this way, valuable metals are recovered in an unoxidized state along with primary gasification by the fluidized bed gasification furnace 10 in the previous stage, and unburned char accompanied with the primary gas is secondary gasified in the high temperature oxidation furnace 30 in the subsequent stage. can do. In the subsequent high-temperature oxidation furnace 30, hydrocarbons, tar, and char are almost completely decomposed by high-temperature gasification at 1200 to 1600 ° C., and the generated gases are H ₂ (hydrogen), CO (carbon monoxide), CO ₂ (carbon dioxide). Carbon) and H ₂ O (water vapor). Further, the slag granulated ash is discharged from the bottom of the high temperature oxidation furnace 30. Thus, valuable metals and slag can be recovered from organic waste, and synthesis gas can be generated.
[0024]
In order to recover the synthesis gas, a gas discharge port 42 provided in the upper part of the quenching chamber 36 of the high-temperature oxidation furnace 30 is connected to a scrubber 56 by a gas line 44, and fine unreacted carbon contained in the secondary gas. And ash is removed. This is intended to separate the solids from the gas by washing the secondary gas with water. Further, an acid gas removing device 58 is disposed at the subsequent stage of the scrubber 56 so that acid gases such as CO ₂ (carbon dioxide), H ₂ S (water vapor), COS (carbonyl sulfide), etc. can be removed and used as a synthesis gas. To be purified. Further, the purified gas is sent to the cold box 60, and CO is cryogenically separated so that the remaining H ₂ is fed to, for example, an ammonia production facility.
[0025]
In such a two-stage gasifier, in this embodiment, the furnace wall structure of the high-temperature oxidation furnace 30 has a castable 64 attached to the inner surface of the iron shell 62, as shown in part in FIG. In addition, fire bricks 66 are laminated on the inner surface, and in particular, the castable 64 has a boiler wall structure in which a cooling medium such as water is circulated through a water pipe 68. With this structure, the surface temperature of the refractory brick wall on the reaction chamber 34 side is set to a temperature necessary for forming the solidified ash coating layer 76.
[0026]
As described above, the primary gas is introduced from the fluidized bed gasification furnace 10 to the high temperature oxidation furnace 30 adopting the boiler wall structure, and the slag mist generated in the process of secondary gasification of the primary gas is positively applied. In this embodiment, a part of the fine slag collected from the quenching chamber 36 of the high-temperature oxidation furnace 30 is pulverized and supplied to the lower part of the free board portion 18 of the fluidized bed gasification furnace 30 in order to deposit and coat the furnace wall. Like to do. Thereby, a fixed amount of ash is always ensured in the primary gas supplied to the high temperature oxidation furnace 30. As a result of the high temperature secondary gasification in the high temperature oxidation furnace 30, the ash contained in the char and the pulverized granulated slag become slag mist, and a molten slag layer is formed on the furnace wall of the reaction chamber 34 by the centrifugal force of the swirling flow. Form. Next, the slag that flows down the furnace wall and enters the quenching chamber 36 and is crushed in the quenching chamber 36 is discharged to the outside through the lock hopper 46 at the lower portion, and is separated into coarse slag and fine slag by the screen 48. Is done. The slag to be returned is preferably fine slag containing unburned char if the gasification efficiency is further increased. In the embodiment, as shown in FIG. 1, the pulverized fine slag is returned.
[0027]
For this reason, a slag return line (ash circulation supply line) 70 is connected to the under-sieving discharge side of the screen 48, and is connected to the fluidized bed gasification furnace 10 via a fine pulverizer 72. Further, an ash bunker 74 is provided adjacent to the slag return line (ash circulation supply line) 70 so that incinerated ash or the like carried in from the outside can be used as supplementary ash. This is because when the organic waste material is waste plastic, the thickness of the deposited ash coating layer on the furnace wall is reduced due to the lack of ash, and HCl (hydrochloric acid) and H ₂ S (hydrogen sulfide) contained in the gas. This is to prevent a situation in which a corrosive gas component such as water damages the water pipe 68 or the like, or a salt in the molten slag wears the firebrick. The total amount of the return slag and supplemental ash may be as long as it is necessary to form a thickness necessary for the ash coating layer in the high-temperature oxidation furnace 30. Specifically, the total amount of the ash contained in the primary gas introduced from the fluidized bed gasification furnace 10, the return slag, and the supplemental ash is commensurate with the amount of the molten ash coating layer that flows down per unit time. You may adjust to.
[0028]
The slag and supplementary ash separated in the high temperature oxidation furnace 30 by such a slag return line (ash circulation supply line) 70 is supplied to the high temperature oxidation furnace 30 along with the primary gas. The furnace wall of the high-temperature oxidation furnace 30 is cooled by the water pipe 68 and has a steep temperature gradient in the horizontal direction of the deposited ash because the surface temperature of the refractory brick 66 is set to the ash solidification temperature. become. Therefore, a solidified ash coating layer 76 deposited on the inner surface of the furnace wall and a molten ash coating layer 78 inside the furnace of the solidified ash coating layer 76 are formed. Therefore, an interface 80 exists between the two layers 76 and 78.
[0029]
The secondary gasification in the high-temperature oxidation furnace 30 is a high-speed reaction, and the furnace temperature fluctuates due to the composition fluctuation of the raw material waste in the fluidized bed gasification furnace 10 in the previous stage. Even if the temperature in the high-temperature oxidation furnace 30 rises to near 1600 ° C. due to the change in the composition of the primary gas, the temperature gradient of the ash deposition layer becomes stronger and the ash deposition amount decreases, but the furnace wall is cooled by the water pipe 68. Therefore, the surface of the refractory brick 66 is protected by the solidified ash coating layer 76. On the contrary, even if the furnace temperature is close to 1200 ° C., the temperature gradient of the ash accumulation layer becomes loose, so the amount of ash accumulation increases, but the surface of the refractory brick 66 is protected by the solidified ash coating layer 76. There is no change. As a result, a self-coating action is obtained, protection by deposited ash in the high-temperature oxidation furnace 30 is ensured, and the furnace wall can be prevented from being damaged by corrosive gas components and molten slag.
[0030]
As described above, in the present embodiment, ash such as slag and incinerated ash of the high-temperature oxidation furnace 30 is supplemented and introduced into the high-temperature oxidation furnace, so that the furnace wall can be protected by the ash self-coating action.
In the above embodiment, ash such as slag and incinerated ash is returned to the fluidized bed gasification furnace 10, but it may be mixed in the raw material, as long as it can be uniformly dispersed in the primary gas. It can be supplied anywhere in the path leading to the high temperature oxidation furnace 30.
[0031]
【The invention's effect】
As described above, according to the present invention, the furnace wall of the high-temperature oxidation furnace has a boiler wall structure with a built-in water tube, and slag or ash generated in the high-temperature oxidation furnace is converted into a low-temperature gasification furnace, a high-temperature oxidation furnace, or both furnaces. An ash circulation supply line is provided in the gas path between them, and is accompanied by the gaseous substance introduced into the high-temperature oxidation furnace so that a deposition coating is formed on the furnace wall during secondary gasification. Since the self-coating action is ensured, it is possible to effectively protect the wall of the high-temperature oxidation furnace and increase its durability.
[Brief description of the drawings]
FIG. 1 is a flowchart of a waste gasification apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a main part of a furnace wall of a high temperature oxidation furnace of a gasification processing apparatus used in the embodiment.
FIG. 3 is a cross-sectional view of a main part of a conventional high-temperature oxidation furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Fluidized bed gasification furnace 12 Organic waste 14 Fixed quantity supply apparatus 16 Fluidized bed part 18 Free board part 20 Neck part 22 Dispersion board 24 Fluidized medium (sand sand)
26 discharge port 30 high temperature oxidation furnace 32 primary gas transfer path 34 reaction chamber 36 quenching chamber 38 throat section 40 water line 42 gas discharge port 44 gas line 46 lock hopper 48 screen 56 scrubber 58 acid gas removal device 60 cold box 62 iron skin 64 Castable 66 Refractory brick 68 Water pipe 70 Slag return line (ash circulation supply line)
72 Fine grinding machine 74 Ash bunker 76 Solidified ash coating layer 78 Molten ash coating layer 80 Interface

Claims (6)

A gasification furnace using a fluidized bed that supplies organic waste and primary gasifies at a low temperature, and a gaseous substance obtained in the fluidized bed gasification furnace is introduced to produce a secondary gas at a high temperature. In a waste gasification apparatus having a high-temperature oxidation furnace, the furnace wall of the high-temperature oxidation furnace has a boiler wall structure or a water-cooled jacket wall structure with a built-in water pipe. An ash circulation supply line that supplies a part of the slag or molten fly ash recovered in this way to the fluidized bed gasifier, high-temperature oxidation furnace, or the gaseous material path between them is installed, and the gaseous material introduced into the high-temperature oxidation furnace A waste gasification apparatus characterized by being able to always form a deposited ash coating layer on the furnace wall during secondary gasification. Set up ash replenishment line such as incinerated ash introduced from the outside in the fluidized bed gasification furnace, high temperature oxidation furnace or the gaseous material path between them, and set the amount of ash to be accompanied by the gaseous material introduced into the high temperature oxidation furnace The waste gasification processing apparatus according to claim 1, wherein the value is ensured. Gaseous materials obtained in the fluidized bed gasification furnace by organic gas such as waste plastic, sewage sludge, shredder dust, municipal waste, etc. supplied to a gasification furnace using a fluidized bed In a waste gasification method for producing useful gas by introducing a gas into a high-temperature oxidation furnace and secondary gasification at a high temperature, the amount of ash contained in the primary gas introduced into the high-temperature oxidation furnace A furnace wall self-coating method in waste gasification treatment, characterized in that it is set to have a set layer thickness of a deposited ash coating layer on a water-cooled wall of the high-temperature oxidation furnace. The set ash amount is determined by circulating and supplying slag generated in a high-temperature oxidation furnace to a fluidized bed gasification furnace, a high-temperature oxidation furnace, or a gaseous material passage therebetween, or incineration ash introduced from the outside. The furnace wall self-coating method in the gasification treatment of waste according to claim 3, wherein the furnace wall self-coating method is performed by supplying through an ash replenishment line. 5. The furnace wall self-coating method in waste gasification processing according to claim 4, wherein the circulating supply slag and supplemental ash are pulverized in advance and the particle size is adjusted. Organic waste such as waste plastic, sewage sludge, shredder dust, and municipal waste is supplied to a fluidized bed gasification furnace for primary gasification, and the gaseous matter obtained in the fluidized bed gasification furnace is oxidized at high temperature. In a waste gasification method for producing useful gas by introducing into a furnace and secondary gasifying at high temperature, a solidified ash coating layer deposited and deposited on a water-cooled wall of the high-temperature oxidation furnace, The water cooling temperature is adjusted so that the molten ash coating layer melted by the furnace temperature is formed on the upper surface of the solidified ash coating layer, and the furnace wall is protected by the solidified ash coating layer. Furnace wall self-coating method in waste gasification.

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