JPH1135949A - Apparatus for gasifying treatment of waste products and process for self-coating of furnace wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability of furnace walls in effecting the primary gasification by a fluidized-bed gasifying furnace and the secondary gasification by a high temperature oxidizing furnace. SOLUTION: This apparatus for the gasifying treatment of waste products comprises a gasifying furnace using a fluidized-bed for the primary gasification of organic waste products supplied thereinto and a high temperature oxidizing furnace 30 for the secondary high temperature gasification of the gaseous substance obtained in the fluidized-bed gasifying furnace 10 and introduced thereinto. The furnace wall of the high temperature oxidizing furnace is made of a boiler wall structure having a water-tube built-in or of a water cooling-jacket wall, structure, and is provided with an ash circulation line for supplying part of the slug or the molten fly ash to be formed in the high temperature oxidizing furnace to the fluidized- bed gasifying furnace 10, the high temperature oxidizing furnace 30 or a gaseous substance channel between the both furnaces to form a deposit coating on the furnace walls accompanied by the gaseous substance to be introduced into the high temperature oxidizing furnace at the time of the secondary gasification. Alternatively, an ash supplement line for burned ash, etc., introduced from the outside into the fluidized-bed gasifying furnace, the high temperature oxidizing furnace or the gaseous substance channel between the both furnaces can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for self-coating furnace walls in gasification of wastes, and more particularly to a high-temperature oxidation furnace in a two-stage gasification system using a fluidized-bed gasification furnace and a high-temperature oxidation furnace. For self-coating furnace walls.

[0002]

[Prior Art] Municipal waste, sewage sludge, waste plastic,
Organic waste typified by waste FRP, biomass waste, automobile waste, waste oil, etc. is generally reduced in volume by incineration or landfilled untreated and recycled. The amount used is negligible overall.

[0003] In the above-mentioned incineration treatment, a stoker furnace or a fluidized bed furnace has been used until now. However, since the air ratio at the time of combustion is high, the amount of exhaust gas is large, and the metals discharged from the furnace are oxidized. Was not suitable for recycling.
Recently, ash melting facilities have been added to such incineration facilities, but this has resulted in an increase in the construction cost and operation cost of the entire apparatus.

In order to solve such a problem, Japanese Patent Application Laid-Open No. Hei 7-332614 was invented, in which organic waste was supplied to a fluidized-bed furnace to be gasified, and valuable metals were taken out in an unoxidized state. By supplying the generated gas to the subsequent melting combustion furnace and completely burning it at high temperature, the ash is converted into molten slag to reduce the volume and make it a stable slag that can be landfilled, extending the life of the landfill disposal site, or as an earth construction material Methods for recycling are presented. In the above method, a flammable gas containing unburned char is generated from waste by a fluidized bed furnace at the former stage, and supplied to a melting furnace at the latter stage to completely burn at a high temperature to convert ash into molten slag. At the same time, it is expected that dioxins will be completely decomposed.

[0005] As described above, when the generated gas of the fluidized-bed gasification furnace is completely burned in the subsequent melting and burning furnace, the heat of the exhaust gas can be used effectively, but the generated gas has a large amount of combustible gas. It can contain a reactive gas component, which can be recycled in the form of a synthesis gas, for example, as a raw material for the chemical industry. This is the concept of so-called chemical recycling.

From such a viewpoint, primary gasification is performed at a relatively low temperature in a fluidized-bed gasification furnace, and the obtained gaseous substance and unburned char are supplied to a high-temperature oxidation furnace to be converted into a secondary gas, and H ₂ ( Useful resources can be achieved by recovering synthesis gas mainly composed of hydrogen) and CO (carbon monoxide). 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, as shown in FIG. It has a structure in which an iron shell 1, castables 2, insulating bricks 3, refractory insulating bricks 4, and refractory bricks 5 are laminated. In such a high-temperature oxidation furnace, when a primary gas obtained by using organic waste as a raw material is supplied to perform secondary gasification 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 salts and the like 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]

However, the primary gas obtained by gasifying organic waste at a low temperature is reduced to 120%.
Since it is difficult to find a brick suitable for a high-temperature oxidation furnace in which gasification is performed at a high temperature of 0 to 1600 ° C. to obtain a secondary gas, three layers of bricks are further laminated in addition to the iron shell 1 and the castable 2 described above. Even if the structure was adopted, the durability was not sufficient. Therefore, the furnace wall of the high-temperature oxidation furnace is cooled by using a boiler wall structure or a water-cooled jacket wall structure with a built-in water pipe, and the entire inside of the furnace is protected by being coated with a sufficient amount of molten slag. It is possible. However, organic wastes such as plastic wastes and biomass wastes have little ash, so it is difficult to cover the entire inside of the furnace of high-temperature oxidation furnaces with molten slag, and attack on firebricks is difficult. It was practically difficult to completely prevent this.

According to the present invention, when performing primary gasification using a fluidized-bed gasification furnace and secondary gasification using a high-temperature oxidation furnace, it is particularly effective 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 waste gasification treatment apparatus and a furnace wall self-coating method that can be performed.

[0009]

In order to achieve the above object, a waste gasification treatment apparatus according to the present invention comprises: a gasification furnace using a fluidized bed for primary gasification of organic waste; A high-temperature oxidation furnace for introducing gaseous matter obtained in a fluidized-bed gasification furnace and secondary gasification at a high temperature.The furnace wall of the high-temperature oxidation furnace has a boiler wall structure containing a water tube or An apparatus having a water-cooled jacket structure, wherein a part of slag or molten fly ash generated in the high-temperature oxidation furnace is supplied to a low-temperature gasification furnace, a high-temperature oxidation furnace, or a gaseous material path between the two furnaces. By providing a supply line and accompanying gaseous matter introduced into the high-temperature oxidation furnace, it was possible to always form a deposited ash coating layer on the furnace wall during secondary gasification. Alternatively, an ash replenishment line such as incineration 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 substance introduced into the high-temperature oxidation furnace is provided. The entrained ash amount can be maintained at a set value.

The method for self-coating furnace wall in gasification of waste according to the present invention supplies organic waste such as waste plastic, shredder dust, municipal waste, sewage sludge to a gasifier using a fluidized bed. The gaseous matter obtained in the fluidized-bed gasification furnace is introduced into a high-temperature oxidizing furnace and gasified into a secondary gas at a high temperature, so that H ₂ (hydrogen), CO (monoxide) can be obtained. In a gasification treatment method for waste which recovers a gas mainly composed of carbon, the amount of ash contained in a primary gas introduced into the high-temperature oxidation furnace is determined by setting a deposited ash coating layer on a water cooling wall of the high-temperature oxidation furnace. The setting is adjusted to be thick. The setting of the ash amount was such that a part of the slag or molten fly ash generated in the high-temperature oxidation furnace was supplied to the low-temperature gasification furnace, the high-temperature oxidation furnace or the gaseous material path between the two furnaces, and was introduced from the outside. Incinerated ash can also be supplied through an ash replenishment line. Further, it is desirable that the supply slag and the replenishment ash are previously adjusted in particle size by pulverization.

Further, organic waste such as waste plastic, shredder dust, municipal waste, and sewage sludge is supplied to a gasification furnace using a fluidized bed to be primary gasified.
In the gasification treatment method for waste gas, in which the obtained gaseous matter and unburned char are introduced into a high-temperature oxidation furnace and secondary gasified at a high temperature to recover a gas mainly containing H ₂ and CO, The water cooling temperature is adjusted so that a solidified ash coating layer adhered and deposited on the inner surface of the water cooling wall of the oxidation furnace and a molten ash coating layer melted by the furnace temperature on the upper surface of the solidified ash coating layer are formed. The solidified ash coating layer protects the firebrick.

[0012]

The organic waste and the oxygen-containing gas are brought into contact in a fluidized-bed gasification furnace at a relatively low temperature (450 to 850).
C) to perform primary gasification by partial oxidation. The obtained high-calorie gaseous substance, unburned char, and oxygen-containing gas are introduced into a high-temperature oxidation furnace, where the high-temperature (1200-1600 ° C.)
, A gas mainly composed of H ₂ (hydrogen) and CO (carbon monoxide) as a useful synthesis gas can be generated.

According to the present invention, the furnace wall of the high-temperature oxidation furnace is cooled by forming a boiler wall structure or a water-cooling jacket wall structure containing a water pipe, and a part of the slag or molten fly ash discharged from the high-temperature oxidation furnace is again heated to a high temperature. Since the ash is supplied to the oxidizing furnace to be melted, a constant amount of ash accompanying the primary gas supplied to the high-temperature oxidizing furnace can be always secured. On the furnace wall, a solidified ash coating layer is formed by a cooling action of a water pipe or the like, and a molten ash coating layer melted by the furnace temperature is formed on the surface layer. Due to the change in the composition of the waste supplied to the fluidized bed gasifier, which is upstream, its calorific value and water content change, the temperature in the furnace of the high-temperature oxidation furnace becomes high, and the fluidity of the ash attached to the furnace wall increases. Even if the layer thickness of the ash coating becomes thinner by increasing, the solidified coating layer can be left by the cooling action of the water pipe,
This protects the firebrick.

When waste plastics, biomass wastes, etc. are used as raw materials, the ash content is small.
It becomes difficult to actively form and maintain the ash coating layer on the furnace wall of the high-temperature oxidation furnace. In such a case, incineration ash, coal ash, etc. may be supplied so that an appropriate amount of ash accompanies the primary gas. The required ash amount 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 falling speed 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 supplied, and the amount of ash replenished from the outside is set to be the required ash amount. do it. It is necessary that the circulating slag and the supplementary ash are pulverized in advance before being introduced into the high-temperature oxidation furnace and adjusted so that the particle size becomes equal to or less than a certain value. If the particle size is coarse, the dispersion in the primary gas becomes non-uniform and quantitative supply becomes impossible, so that the ash particle size is reduced to ensure the formation of the ash coating.

For protecting 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 brick, the protection of the furnace wall can be enhanced by lowering the cooling temperature and increasing the thickness of the solidified ash coating layer. However, the temperature of the surface of the water cooling section shall be higher than the dew point of the generated 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, steel shell). There is a need to.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The waste gas according to the present invention will be described below.
Of concrete treatment apparatus and furnace wall self-coating method
Embodiments will be described in detail with reference to the drawings. Figure 1
FIG. 3 is a flowchart of a waste gasification treatment apparatus according to the embodiment.
You. The gasification treatment equipment is operated in a fluidized bed gasification furnace at the previous stage.
Primary gasification at a relatively low temperature of 450 to 850 ° C
After entraining unburned char in the secondary gas,
Gasification at 1200-1600 ° C in a high temperature oxidation furnace
By doing, H 2 (SK hydrogen), CO (carbon monoxide)
Elementary) Synthetic gas is mainly generated.

First, municipal solid waste, sewage sludge, solidified fuel, slurry fuel, waste plastic, waste FRP, biomass waste,
Organic waste such as automobile waste and waste oil and bottom-grade coal can be used. The organic waste is supplied after being roughly crushed to about 30 mm, and the solid fuel, the slurry fuel, and the waste oil are supplied as they are. The low-grade coal is supplied after being crushed to about 40 mm. After these are received in a pit and sufficiently stirred and mixed, the fluidized bed gasifier 1
0. If the properties (calorific value and moisture) of the waste to be gasified are not good, it is possible to add coal, oil coke or the like as an auxiliary material if necessary. The amount to be added is appropriately determined depending on the properties of the waste. The organic waste 12 previously crushed as required is supplied to a hopper, and then supplied to a screw-type quantitative supply device 14.
Is supplied to the fluidized bed gasifier 10 using

Fluidized bed gasifier 1 into which the above waste is charged
0 indicates the lower fluidized bed section 16 and the upper free board section 18
And both are communicated via the neck portion 20. The fluidized bed section 16 is filled with sand (silica sand, olivine sand, etc.), alumina, iron powder, limestone, dolomite, or the like as a fluid medium 24 on a dispersion plate 22 arranged at the furnace bottom. The fluidizing medium 24 is fluidized by ejecting the fluidizing gas into the layer of the fluidizing medium 24 via the fluidizing medium. The dispersing plate 22 has a shape in which a cone protruding from the center is turned down, and the fluidizing gas is divided and supplied to a central portion and a peripheral portion of the dispersing 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 generated 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 the recycle gas is similarly added to make the oxygen concentration equal to or higher than that of the central part. Thus, a swirling motion is generated in the fluidized bed such that the fluidized medium 24 has a downward flow at the central portion of the fluidized bed portion and an upward flow at the peripheral portion.

Since the central fluidized gas has a low oxygen concentration, the combustible gas having a large calorific value including tar generated in the fluidized bed formed as a downward flow in the central portion of the fluidized bed is slightly dry-dried. After being pyrolyzed and gasified under conditions close to the above, it rises to the free board section 18. The char, which is a solid produced in the central fluidized bed, is circulated to the peripheral fluidized bed together with the fluidized medium, and partially burns the char by contacting the peripheral fluidized gas having a relatively high oxygen concentration. And becomes CO, CO ₂ main gas, and the inside of the furnace becomes 45
Generates heat that is maintained at 0-850 ° C. Thus, gas, tar, and char are generated in the fluidized bed by the primary gasification. However, the lower the temperature is, the higher the generation rate of tar and char is, and the lower the gas generation rate is. Since the entire interior of the gasifier is kept in a reducing atmosphere, the metals contained in the waste, whose melting point is higher than the fluidized bed temperature, are discharged together with the fluidized medium from the bottom of the gasifier as unoxidized valuable metals. Is done.
Therefore, for example, when the fluidized bed temperature is lower than 660 ° C., which is the melting point of aluminum, aluminum can be recovered in an unoxidized metal state. For this recovery, an outlet 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 incombustibles can be recovered from the outlet 26 in an unoxidized and clean state. At the same time, the silica sand of the fluid medium 24 discharged together with the non-combustible material from the discharge port 26 is separated upward by a dispensing operation, and then conveyed upward using a bucket conveyor or the like, and returned to the fluidized-bed gasification furnace 10. .

The organic waste introduced into the fluidized bed 16 of the gasification furnace 10 becomes gas, tar, and char by primary gasification, and the gas and tar evaporate and rise in the furnace.
The char is refined by the swirling motion of the flowing medium while undergoing partial oxidation. The micronized char is porous and light, so it is entrained in the upward flow of gas. By using hard silica sand for the fluid medium 24, the grinding of the char is further promoted. The gas, tar, and unburned char exiting the fluidized-bed gasification furnace 10 are supplied to the next-stage high-temperature oxidation furnace 30, where CO (carbon monoxide), H ₂ (hydrogen) )
The main synthesis gas is generated.

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 a primary gas transfer path 32. A burner is attached to the top of the high-temperature oxidation furnace 30. By separately supplying the primary gas and the oxygen gas as a gasifying agent 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 below the high-temperature oxidizing furnace 30, and the reaction chamber 34 and the quenching chamber 36 communicate with each other through a throat section 38. A water line 40 for sending water for gas quenching is opened in the quenching chamber 36 to supply and discharge water so as to have an appropriate water level. The secondary gas generated in the reaction chamber 34 passes through the throat section 38 and is blown into the water in the quenching chamber 36, and then passes through a gas discharge port 42 provided above the water surface of the quenching chamber 36 to a gas line 44. To the following scrubber 56.

In this case, it is desirable to supply the primary gas to the high-temperature oxidizing furnace 30 so as to form a swirling 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 rapidly gasified at 1200 to 1600 ° C. while being mixed with the gasifying agent in a swirling flow by the combustion flame and the radiant heat from 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 due to the centrifugal force of the swirling flow, and flows down the furnace wall to the quenching chamber 36. The slag is granulated into slag particles in the quenching chamber 36, discharged to the outside via the lock hopper 46, and separated by the screen 48 into coarse slag and fine slag.

In this way, the fluidized bed gasifier 10 in the first stage
The valuable metal is recovered in an unoxidized state along with the primary gasification by, and the unburned char accompanying the primary gas can be converted into a secondary gas in the high-temperature oxidation furnace 30 in the subsequent stage. 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.
The generated gas is H ₂ (hydrogen), CO (carbon monoxide), CO
₂ (carbon dioxide) and H ₂ O (steam). Further, the ash that has become slag granulated is discharged from the furnace bottom of the high-temperature oxidation furnace 30. In this way, valuable metals and slag can be recovered from organic waste, and a synthesis gas can be generated.

In order to recover the synthesis gas, a gas outlet 42 provided above the quenching chamber 36 of the high-temperature oxidation furnace 30 is provided.
Is connected to a scrubber 56 by a gas line 44 to remove fine unreacted carbon and ash contained in the secondary gas. In this method, the secondary gas is washed with water to separate solids from the gas. Also scrubber 5
6 is provided with an acid gas removing device 58 in which acid gases such as CO ₂ (carbon dioxide), H ₂ S (steam), and COS (carbonyl sulfide) are removed and purified so that it can be used as a synthesis gas. I do. Further, the purified gas is sent to the cold box 60 and CO is cryogenically separated so that the remaining H ₂ is sent to, for example, an ammonia production facility.

In such a two-stage gasifier, in this embodiment, the furnace wall structure of the high-temperature oxidation furnace 30 has a castable 64 on the inner surface of a steel shell 62, as shown in FIG. And fire refractory brick 6
In particular, the castable 64 has a boiler wall structure through which a cooling medium such as water flows through a water pipe 68. With this structure, the surface temperature of the refractory brick wall on the side of the reaction chamber 34 is set to a temperature necessary for forming the solidified ash coating layer 76.

High-temperature oxidation furnace 3 employing the above-mentioned boiler wall structure
As described above, primary gas is introduced from the fluidized bed gasifier 10 as described above. In order to positively deposit and coat slag mist generated in the process of secondary gasification of the primary gas on the furnace wall, In this embodiment, a part of the fine slag collected from the quenching chamber 36 of the high-temperature oxidation furnace 30 is finely pulverized and then supplied to a lower portion of the free board section 18 of the fluidized-bed gasification furnace 30. Thereby, a certain amount of ash is always secured in the primary gas supplied to the high-temperature oxidation furnace 30. The ash contained in the char and the finely ground granulated slag included in the char with the high-temperature secondary gasification in the high-temperature oxidation furnace 30 become slag mist, and the 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 flowing down the furnace wall and entering the quenching chamber 36 is slag granulated in the quenching chamber 36 is discharged to the outside through the lower lock hopper 46, and is separated into coarse slag and fine slag by the screen 48. Is done.
The slag to be returned is preferably a fine slag containing unburned char if the gasification efficiency is further increased. In the embodiment, as shown in FIG. 1, the crushed fine slag is returned.

For this purpose, a slag return line (ash circulation supply line) 70 is connected to the screen 48 under the sieve discharge side, and connected to the fluidized bed gasification furnace 10 via a pulverizer 72. An ash bunker 74 is provided adjacent to the slag return line (ash circulation supply line) 70 so that incinerated ash or the like brought in from the outside can be used as supplementary ash. This is because when the organic waste of the raw material is waste plastic, etc., the thickness of the ash coating layer deposited on the furnace wall becomes thin due to lack of ash, and HCl contained in the gas is used.
This is to prevent a corrosive gas component such as (hydrochloric acid) and H ₂ S (hydrogen sulfide) from damaging the water pipe 68 and the like, and preventing salts in the molten slag from abrading the refractory brick. The total amount of the returned slag and the replenished ash may be an amount necessary to form a required thickness as an ash coating layer in the high-temperature oxidation furnace 30. Specifically, the fluidized bed gasifier 1
The ash contained in the primary gas introduced from zero, the return slag, and the total amount of the replenishment ash may be adjusted to match.

The slag and replenishment ash separated in the high-temperature oxidation furnace 30 are supplied to the high-temperature oxidation furnace 30 together with the primary gas by the slag return line (ash circulation supply line) 70. Since the furnace wall of the high-temperature oxidation furnace 30 is cooled by the water pipe 68 and the surface temperature of the refractory brick 66 is set to the ash solidification temperature, the steep ash has a steep temperature gradient in the horizontal direction. become. Therefore, the ash layer has a solidified ash coating layer 76 deposited and deposited on the inner surface of the furnace wall,
The solidified ash coating layer 76 and the molten ash coating layer 78 inside the furnace are formed. Therefore, both layers 76, 7
8, there is a boundary surface 80.

The secondary gasification in the high-temperature oxidizing furnace 30 is a high-speed reaction, and the temperature inside the furnace varies due to the composition variation of the raw material waste in the fluidized-bed gasification furnace 10 in the preceding stage. Due to a change in the composition of the primary gas, the temperature in the high-temperature oxidation furnace 30 becomes 160
Even when the temperature rises to near 0 ° C., the amount of ash deposited decreases due to the increase in the temperature gradient of the ash deposit layer, but since the furnace wall is cooled by the water pipe 68, the surface of the refractory brick 66 has a solidified ash coating. Protected by layer 76. Conversely, even when the furnace temperature is close to 1200 ° C., the amount of ash deposition increases because the temperature gradient of the ash deposition layer becomes gentle, 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 effect is obtained, protection by the deposited ash in the high-temperature oxidation furnace 30 is secured, and the furnace wall can be prevented from being damaged by corrosive gas components and molten slag.

As described above, in the present embodiment, the high-temperature oxidation furnace 30 is used.
By replenishing ash such as slag and incinerated ash and introducing it into a high-temperature oxidation furnace, the self-coating action of the ash
The furnace wall can be protected. In the above embodiment, ash such as slag and incinerated ash is returned to the fluidized-bed gasification furnace 10, but may be mixed in the raw material, as long as it can be uniformly dispersed in the primary gas. High temperature oxidation furnace 30
Can be supplied anywhere in the route to.

[0031]

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 pipe, and the slag or ash generated in the high-temperature oxidation furnace is converted into a low-temperature gasification furnace and a high-temperature gasification furnace. An ash circulation supply line is provided to supply gas to the oxidation furnace or to the gaseous material path between the two furnaces, so that the gaseous matter introduced into the high-temperature oxidation furnace is entrained to form a deposited coating on the furnace wall during secondary gasification. Thus, the self-coating action of the furnace wall is ensured, so that the furnace wall of the high-temperature oxidation furnace can be effectively protected and its durability can be increased.

[Brief description of the drawings]

FIG. 1 is a flowchart of a waste gasification treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a furnace wall of a high-temperature oxidation furnace of the gasification processing apparatus used in the embodiment.

FIG. 3 is a sectional view of a main part of a furnace wall of a conventional high-temperature oxidation furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fluidized-bed gasification furnace 12 Organic waste 14 Quantitative supply device 16 Fluidized-bed part 18 Free board part 20 Neck part 22 Dispersion board 24 Fluid medium (silica sand) 26 Outlet 30 High-temperature oxidation furnace 32 Primary gas conveyance path 34 Reaction chamber 36 Rapid cooling room 38 Throat part 40 Water line 42 Gas outlet 44 Gas line 46 Lock hopper 48 Screen 56 Scrubber 58 Acid gas remover 60 Cold box 62 Iron shell 64 Castable 66 Refractory brick 68 Water pipe 70 Slag return line (ash circulation supply line) ) 72 pulverizer 74 ash bunker 76 solidified ash coating layer 78 molten ash coating layer 80 interface

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F23G 5/48 ZAB F23G 5/48 ZAB F23M 5/08 F23M 5/08 A (72) Inventor Akisaku Fujinami Haneda Ota-ku, Tokyo 11-1 Asahicho Ebara Corporation

Claims (6)

[Claims] 1. A gasification furnace using a fluidized bed for supplying organic waste and primary gasifying at a low temperature, and introducing a gaseous substance obtained in the fluidized bed gasification furnace to a high temperature. In a waste gasification treatment apparatus having a high-temperature oxidation furnace for secondary gasification, the furnace wall of the high-temperature oxidation furnace has a boiler wall structure or a water-cooled jacket wall structure containing a water pipe, and the high-temperature oxidation furnace or An ash circulation supply line is provided to supply a part of the slag or molten fly ash recovered by the dust remover at the subsequent stage to the fluidized bed gasification furnace, high-temperature oxidation furnace or gaseous material path between them, and it is introduced into the high-temperature oxidation furnace. Waste gasification treatment apparatus capable of constantly forming a deposited ash coating layer on a furnace wall during secondary gasification by being accompanied by a gaseous substance. 2. An ash replenishment line such as incineration ash introduced from the outside is provided in the fluidized bed gasification furnace, the high-temperature oxidation furnace, or a gaseous substance path therebetween to accompany gaseous substances introduced into the high-temperature oxidation furnace. The waste gasification apparatus according to claim 1, wherein an amount of ash to be produced is secured at a set value. 3. A primary gasification of organic wastes such as waste plastics, sewage sludge, shredder dust, and municipal waste by supplying the same to a gasification furnace using a fluidized bed and obtaining the same in the fluidized bed gasification furnace. In the gasification treatment method for waste, which generates a useful gas by introducing the gaseous matter into a high-temperature oxidation furnace and secondary gasification at a high temperature, the primary gas introduced into the high-temperature oxidation furnace contains A method of self-coating a furnace wall in gasification of waste, wherein the amount of ash to be used is set to a set thickness of a deposited ash coating layer on a water cooling wall of the high-temperature oxidation furnace. 4. The set ash amount is obtained 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 path therebetween, or introduced from outside. 4. The method according to claim 3, wherein the incinerated ash is supplied through an ash replenishment line. 5. The method according to claim 4, wherein the circulating feed slag and the supplementary ash are pulverized in advance and adjusted in particle size. 6. A gas obtained in the fluidized-bed gasification furnace by supplying organic wastes such as waste plastic, sewage sludge, shredder dust, and municipal waste to the fluidized-bed gasification furnace by supplying the waste to the fluidized-bed gasification furnace. A waste gasification method for producing useful gas by introducing a gaseous substance into a high-temperature oxidation furnace and secondary gasification at a high temperature, wherein solidified ash adhered and deposited on a water cooling wall of the high-temperature oxidation furnace The water cooling temperature was adjusted so that the coating layer and the molten ash coating layer melted by the furnace temperature on the upper surface of the solidified ash coating layer were formed to protect the furnace wall with the solidified ash coating layer. A method for self-coating a furnace wall in gasification of waste.