JP2001208318A - Gasification melting furnace for waste and therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gasification melting furnace and method that allows waste to be subjected to gasification for melting, and collect fuel gas, molten slag, molten metal, or heavy metal with a low boiling point. SOLUTION: In the gasification melting furnace and the gasification melting method using the gasification melting furnace, a waste-loading port 11-1 for loading waste, and a gas discharge port 3-1 for discharging gas to be generated are provided at an upper part, a discharge port 9 for discharging the molten slag and molten metal is provided at a lower part, ports 5-1 to 5-3 being divided into a plurality of stages (normally, three stages) are provided in a height direction that can independently blow a burning-supporting gas and auxiliary fuel on a furnace wall. In addition, a means 17 for measuring the level of the loaded waste, means 20 and 21 for measuring temperature in the furnace, and an upward-blowing lance 24, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas (hereinafter referred to as energy) which can be used as a fuel by gasifying organic substances contained in general waste and industrial waste (hereinafter simply referred to as waste). Gas) or low-boiling heavy metals contained in these wastes as dust, and ash and valuable metals (hereinafter also simply referred to as metals) contained in these wastes, respectively. The present invention relates to a gasification and melting furnace and a gasification and melting method for waste collected as molten slag and molten metal.

[0002]

2. Description of the Related Art As a method of treating general waste mainly composed of municipal waste and industrial waste mainly composed of shredder dust of discarded automobiles and home electric appliances, a method of landfill disposal or landfill disposal after incineration is known. Has been adopted. However, given the recent tight situation that it is extremely difficult to secure landfill sites, the incineration method generally used so far has been reviewed.

Further, instead of directly discarding the waste or landfilling it after incineration, the waste once reduced in volume and solidified, that is, RDF (Refuse Derived) is generally used.
Fuel is a solid fuel called waste-derived fuel) and then incinerated, and some have been put to practical use. Examples of the waste treatment system using this method include a TC-system by Japan Recycling Management Co., Ltd., a J-Catrel system by Ebara Corporation, and a recycling energy center concept in Mie Prefecture (No. 6). Of the seminar “Seminar on Solid Waste Fuel Technology”, June 28, 1996 (Environmental Planning Center).

On the other hand, from the standpoint of protecting limited resources, these wastes or RDF are not simply incinerated,
It is desirable to recover recyclable materials as resources (useful substances) or energy (heat energy).
The following are examples that are currently in practical use. 1. Material recovery Separation and recovery of metals (aluminum cans, steel cans, etc.) Separation and recovery of plastics (PET bottles, etc.) Separation and recovery of waste paper (newspaper, etc.) 2. Material conversion and recovery Recovery of plastics as fuel oil by pyrolysis oil recovery Recovery of plastics as fuel gas by pyrolysis gasification Thermal energy recovery Steam recovery at the time of waste incineration Since the above item 1 is a pre-treatment method before waste, the recovery of useful substances from waste after separation must rely on the above two or three means. I can't. In particular, recently, general waste and industrial waste contain various substances due to changes in lifestyle (diversification). Chemical systems are in the spotlight.

[0005] The gasification system is as follows. A. Nippon Steel's coke bed type direct melting system (“Steel Industry Bulletin” No. 1674, 1996.3.21
(Japan Iron and Steel Federation), “Fuel and Combustion,” Vol. 61, No. 8, (1994), pp. 572-578, and Tokuhei 7-35
The main body of the melting furnace is a single-stage tuyere vertical shaft furnace, into which coke and limestone are charged together with waste from the center of the furnace. The furnace is preheated and dried from the top (about 3
00 ° C), thermal decomposition zone (300-1000 ° C) and combustion / melting zone (1700-1800 ° C). In the preheating / drying zone, waste is heated and moisture evaporates. The dried waste gradually descends and moves to the pyrolysis zone where the organic matter is gasified. This generated gas is discharged from the upper part of the furnace,
The fuel is completely burned in the latter combustion chamber, and heat energy is recovered by a heat recovery system such as a waste heat boiler.

[0006] On the other hand, the remaining gasified ash and inorganic substances fall into the combustion / melting zone together with coke. The coke is burned by the air supplied from the tuyere, and the heat causes the ash and inorganic substances to completely melt. The melt is adjusted to an appropriate viscosity and basicity by the charged limestone, and discharged from the taphole to the outside of the furnace.

In order to reduce coke, a method is disclosed in which a separate charging system for coke and waste is used to utilize the sensible heat of exhaust gas for drying and preheating waste, thereby increasing the thermal efficiency of the furnace. (Japanese Patent Publication No. 7-35889). B. NKK high-temperature gasification direct melting system ("Steel Industry Report" No. 1674, 1996.3.21
(Japan Iron and Steel Federation)) The melting furnace body is a vertical furnace having tuyeres divided into three stages in the height direction, and the flow formed by the dry distillate of waste maintained at a high temperature of about 1000 ° C. Waste is directly injected into the formation along with auxiliary fuel such as coke. By blowing air from the middle tuyere (two-stage tuyere) into the fluidized bed, part of the generated gas is burned and the temperature is maintained.

[0008] The dry distillate containing incombustibles descends to the moving bed at the lower part of the furnace together with the auxiliary fuel, and is burned and gasified at high temperature by oxygen-enriched air from the lower tuyere (main tuyere). It is melted, dropped and separated from metal by the difference in specific gravity. On the other hand, the freeboard temperature is always 1000 by the air blown from the tuyere (three-stage tuyere) installed under the freeboard.
The temperature is maintained at not less than ° C., thereby preventing the generation of tar components and the production of dioxins and their precursors. C. Thermoselect method (Thermoselect (1995.5.26),
PART1 "Foundation for the continuos conversio
ns of solid waste ”) The furnace used in this method is a pressurized tubular pyrolyzer that evaporates moisture in waste and pyrolyzes organic matter, and the combustion of pyrolysis residue (char) by oxygen, ash This is a pyrolysis melting furnace that is integrally connected with a combustion melting furnace that melts and reforms gas.In the combustion melting furnace, first, the decomposition gas of organic substances from the pyrolyzer is sent to the middle part of the furnace. On the other hand, the char falls to the bottom of the furnace, burns at high temperature with oxygen to melt the ash, and converts organic decomposition gas to CO and H ₂ under a high temperature atmosphere at the top of the furnace (gas reforming). However, the above-mentioned conventional method has the following problems: the vertical shaft furnace of the above-mentioned method A requires expensive coke and completely burns the generated gas, so that it is not obvious. Only heat can be recovered. In this method, since the temperature of the preheating / drying zone in the upper part of the furnace is about 300 ° C., a large amount of hydrocarbons such as tar and dioxins which cannot be sufficiently decomposed are discharged outside the furnace. Since coke is not sufficiently gasified and remains in the molten slag, coke is indispensable to reduce this slag.The vertical furnace of the system of system B also requires expensive coke as in the case of system A. This is necessary because heavy metals having a low boiling point are not sufficiently gasified and remain in the molten slag, so that the slag is reduced.
In order to maintain the temperature at 000 ° C. or higher, a large free board is required, and an increase in the size of the furnace is inevitable. Although the furnace used in the method C is said to have two reactors (furnace) connected integrally, it is actually clearly separated into two furnaces, a pyrolysis furnace and a combustion melting furnace. Therefore, it is structurally complicated and the equipment cost increases. Further, since the pyrolysis furnace is an indirect heating type furnace separated from the combustion melting furnace, the sensible heat of the exhaust gas of the combustion melting furnace is not sufficiently utilized.

[0009]

SUMMARY OF THE INVENTION In connection with the problem of landfill sites, the present invention is to effectively use combustibles, ash, iron, etc. in wastes, and to reduce the costs associated with landfills. It is intended to utilize the by-product gas generated as fuel for power generation and the like. That is, an object of the present invention is not to simply incinerate general waste and industrial waste, but to gasify organic substances contained in the waste and recover it as an energy gas, and to reduce ash content and iron contained in the waste. Valuable metals such as (Fe) and copper (Cu) are recovered as molten slag and molten metal, respectively, or mercury (Hg) and cadmium (C) contained in waste.
d) to provide a method for recovering harmful low-boiling heavy metals such as lead (Pb) as dust, and a furnace therefor. Specifically, a series of steps of gasification and melting of waste, dehydration / pyrolysis, and gas reforming were carried out in one furnace without using expensive coke to solve the above-mentioned problems in the prior art. It is another object of the present invention to provide a gasification melting furnace and a gasification melting method capable of producing clean exhaust gas free of tar, dioxin, and the like.

[0010]

The gist of the present invention resides in the following waste gasification and melting furnace (1) and gasification and melting method (2). (1) Combustion of waste, gasification of organic matter in waste and recovery as energy gas, and gasification of low-boiling heavy metals in waste to recovery as dust accompanying energy gas and disposal A vertical waste gasification and melting furnace for recovering ash and metals in a material as a molten material, wherein a waste loading inlet for charging the waste at an upper portion and discharging generated gas and dust are provided. A gas discharge port and dust recovery means connected to the gas discharge port via a gas discharge duct, and a discharge port for molten slag and molten metal at a lower portion; A tuyere capable of independently injecting a supporting gas and an auxiliary fuel between the discharge port and
It has at least one tuyere in the height direction including a tuyere for burning and gasifying carbides produced by dehydration and pyrolysis of waste, and can be raised and lowered toward the furnace at the top of the furnace An upper blowing lance capable of injecting a supporting gas and an auxiliary fuel, furthermore, a means for measuring the level of the loaded waste, a means for measuring the temperature near the tuyere in the middle stage,
And a means for measuring the temperature of the atmospheric gas in the upper part of the furnace. (2) A method for gasifying and melting waste using the waste gasification and melting furnace described in (1) above, wherein the waste charged into the furnace from a waste inlet is provided by each of the following: By the reaction in the zone, energy gas mainly composed of CO and H ₂ and dust containing low-boiling heavy metals, molten slag and molten metal are collected, and the former is recovered from a gas outlet provided at the upper part of the furnace to recover energy. A gasification and melting method for waste, comprising separating gas and dust, and collecting the latter from a discharge port of molten slag and molten metal provided in a lower part of the furnace. [First Zone] A supporting gas and, if necessary, auxiliary fuel are blown from the lower tuyere to burn and gasify the carbide generated in the second zone to generate a reducing gas, and to reduce ash contained in the carbide. The metals are melted into molten slag and molten metal. [Second Zone] The supporting gas and, if necessary, auxiliary fuel are blown from the tuyere in the middle stage and / or the upper blowing lance,
The reducing gas generated in the zone is secondarily burned, and the waste charged from the waste loading inlet is dehydrated and heated to thermally decompose into carbide and hydrocarbon gas, while gasifying low-boiling heavy metals. In addition, the above-mentioned “(1)“ Tuye divided into multiple stages ”
The term “plural stages” means, in practice, three stages, but is not necessarily limited to three stages.
It may be more than a step.

The "zone" of the above (2) is a region in the furnace, which will be described later, and is referred to as a first zone, a second zone and a third zone according to the reaction occurring therein.

The "low-boiling heavy metals" in the above (1) include mercury (Hg), cadmium (Cd), lead (Pb) and 1
Metals such as arsenic (As) and zinc (Zn) having a high vapor pressure at a temperature of 200 ° C. or lower, or chlorides of these metals, ie, HgCl ₂ , CdC
l ₂ , PbCl ₂ , ZnCl _{2 and the} like, or oxides of these metals, ie, HgO, CdO, PbO, ZnO
Or the sulfides of these metals, ie HgS, C
It refers to elements designated as environmentally harmful, such as dS, PbS, and ZnS, and compounds thereof.

The “metals” in the above (1) refer to valuable metals as described above, and include, for example, aluminum (Al), nickel (N) in addition to iron (Fe) and copper (Cu).
Metals such as i) and oxides thereof, which are generally evaluated as valuable if recovered.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention (the above (1) and (2)) will be described below in detail with reference to the drawings. FIG.
It is a schematic longitudinal cross-sectional view showing a configuration of an example of the waste gasification and melting furnace of the invention (1).

As shown, waste gasification and melting furnace 1
Is a waste inlet 11- for charging waste at the top.
1 and a gas outlet 3-1 for discharging generated energy gas and dust accompanying the energy gas. The hopper 11-
2 and a pusher 10, and a hot cyclone (dust collecting means) 25 for collecting energy gas and dust (indicated as exhaust gas 4 in the figure) is provided at a gas outlet 3-1. 2 are attached. The energy gas and the dust pass through the hot cyclone 25 and the energy gas 26
And dust 27. As a dust collecting means, a hot cyclone is inexpensive and is economically preferable, but a dust removing device such as a bag filter may be used.

In the lower part of the furnace, molten slag and molten metal 13 are provided.
A slag discharge port 9 for discharging slag is provided.

Between the gas discharge port 3-1 and the discharge port 9 of the molten slag and the molten metal, vanes divided into three stages in the height direction into which the supporting gas and the auxiliary fuel can be independently blown are provided. A mouth is provided. This is because, in order from the bottom of the furnace, the waste is dehydrated and heated, and the combustion supporting gas 7- is added to the packed bed 14 mainly composed of carbide generated by thermal decomposition.
1 and the tuyere for injecting the auxiliary fuel 6-1 (the lower tuyere, hereinafter referred to as "primary tuyere 5-1"), and the packed bed 15 mainly composed of the loaded waste. Tuyere (a middle tuyere, hereinafter referred to as "secondary tuyere 5-2") for injecting the supporting gas 7-2 and the auxiliary fuel 6-2 into the 7-3 and auxiliary fuel 6-
3 is a tuyere for injecting the third tuyere (the upper tuyere, hereinafter referred to as “tertiary tuyere 5-3”). In addition, the supporting gas is
Pure oxygen or a gas containing oxygen, and the auxiliary fuel is a solid fuel such as pulverized coal, a liquid fuel such as heavy oil, or a gas fuel such as natural gas. In addition, since the packed bed 15 mainly composed of waste is charged with limestone at the same time as waste to lower the viscosity of the molten slag and molten metal and smoothly discharge the molten slag and the molten metal from the outlet 9 at the lower part of the furnace, some limestone is used. They are mixed.

Further, on the upper part of the waste gasification and melting furnace 1, an upper blowing lance 24-1 capable of injecting a supporting gas and, if necessary, an auxiliary fuel, and this lance 24-1
Is provided with a lance elevating device 24-2 for elevating the lance. In the above gasification and melting furnace, the waste loading inlet 11-
1 is installed between the secondary tuyere 5-2 and the tertiary tuyere 5-3, but is not limited to this position, and is used in the case of the gasification and melting furnace shown in FIG. Like the third tuyere 5
-3. However, as in this example, the one installed between the secondary tuyere 5-2 and the tertiary tuyere 5-3 is a waste gas in which clean gas after reforming in the third zone falls. This is desirable because it does not collide with objects and has little pollution of clean gas and scattering of waste. Further, in this example, three-stage tuyeres are provided between the gas outlet 3-1 and the outlet 9 for the molten slag and the molten metal. It is sufficient that at least one stage is provided including a tuyere for burning and gasifying carbide generated by pyrolysis, that is, a primary tuyere attached to the first zone in the furnace. 1
In the case of a step, the above upper lance 24-1 is used,
This will be described in an embodiment described later.

Further, in this gasification melting furnace, a sounding device 17 for measuring the level of the waste (the top level of the raw material layer) charged in the furnace is provided at the upper part of the furnace. In addition, a thermocouple 20 for measuring the temperature near the middle tuyere (secondary tuyere 5-2) is provided on the furnace side wall,
A thermocouple 21 for measuring the temperature of the atmosphere gas in the upper part of the furnace (that is, the temperature of the exhaust gas in the freeboard space) and a temperature converter 19 for converting a signal of the thermocouple into a temperature are attached. The temperature in the vicinity of the middle tuyere (secondary tuyere 5-2) refers to the temperature of the second zone corresponding to the secondary tuyere 5-2. In this gasification and melting furnace,
The reason why the tuyere is provided in three stages in the height direction of the furnace, the reason that the sounding device 17 is provided, and the thermocouple is attached to a predetermined portion of the furnace side wall will be described in the following (2). The invention will be described together with the method for gasifying and melting waste.

As described above, this gasification and melting furnace is a vertical, one-furnace type gasification and melting furnace, which can simplify the equipment and reduce the equipment cost. This is a preferable method from the viewpoint of suppressing heat loss. Further, if this gasification and melting furnace is used, as described below, mercury (Hg), cadmium (Cd), lead (P
Harmful low-boiling heavy metals such as b) can be recovered as dust. The method for gasifying and melting waste according to the invention (2) is a method for gasifying and melting waste using the gasification and melting furnace according to the invention (1). Hereinafter, the case of using the gasification and melting furnace shown in FIG. 1 will be described.

First, the waste is put into the hopper 11-2, and is pushed in by the pusher 10 to push the waste inlet 11-1.
From the furnace. Next, energy gas mainly composed of CO and H ₂ is recovered by the reaction in the first to third zones described in detail below.
Dust containing low-boiling heavy metals is recovered together with energy gas from a gas outlet 3-1 provided in the upper part of the furnace. Further, the obtained molten slag and molten metal are collected from a discharge port 9 of the molten slag and molten metal provided at the lower part of the furnace. In the furnace, there are three regions according to the reaction that takes place, that is, a region where carbide is gasified and melted in order from the bottom of the furnace (first zone 14), dewatering / pyrolysis of waste, and gasification of low-boiling heavy metals. (The second zone 15) and the region where the gas reforming proceeds and where the dust containing the low-boiling heavy metals is discharged out of the furnace accompanying the gas (the third zone 16). It is divided (see FIG. 1). The above-mentioned primary tuyere 5-1, secondary tuyere 5-2, and tertiary tuyere 5-3 that can independently inject the supporting gas and auxiliary fuel necessary for the reaction into each zone. Are mounted correspondingly, and an upper blowing lance 24-1 is further mounted. By adopting such a configuration, the organic matter contained in waste can be efficiently gasified to recover energy gas that can be used as fuel, and the low-boiling heavy metals contained in these waste can be efficiently recovered as dust. At the same time, the ash and valuable metals contained in these wastes can be efficiently recovered as molten slag and molten metal, respectively. In addition, it is possible to avoid the hanging of a shelf and the occurrence of blow-through, which are peculiar to a vertical furnace.

In the first zone, a reaction represented by the following equation occurs. This reaction is a reaction in which the carbide (filled bed) that has been formed in the second zone and descends is burned by the supporting gas 7-1 blown from the primary tuyere 5-1. The carbide is burned and gasified. , A reducing gas mainly composed of CO at 2000 ° C. or higher. In addition, the ash (inorganic oxide) and valuable metals contained in the carbide are melted by the sensible heat,
It becomes molten slag and molten metal. In addition, the auxiliary fuel 6-1 is supplied from the primary tuyere 5-1 if necessary.

The reducing gas moves to the second zone,
The molten slag and the molten metal are recovered from an outlet 9 at the bottom of the furnace. C + 1 / 2O ₂ = CO where C: carbide supplied from the second zone O ₂ : oxygen in the combustible gas blown from the primary tuyere In addition, the waste is dehydrated in the second zone The reason why gasification and melting of the carbide in the first zone by forming a packed bed of carbide by pyrolysis is as follows. Dividing into two stages in this way promotes heating of the carbide, heat loss from molten slag and molten metal. This is because it is possible to effectively suppress the above.

In the first zone, it is necessary to completely melt the ash and valuable metals contained in the carbide by the sensible heat of the reducing gas to be generated.
It is preferable to keep the temperature at 00 ° C. or higher. For this purpose, the oxygen concentration in the supporting gas is set to 50% or more, and auxiliary fuel is blown if necessary. In order to discharge the molten slag and the molten metal smoothly from the discharge port at the bottom of the furnace without causing clogging or the like, limestone is simultaneously charged from above the furnace when the waste is charged into the furnace, or It is preferable to reduce the viscosity of the slag by blowing powdery limestone as a slag-making material from the next tuyere. In the second zone, the reactions represented by the following formulas (1) to (3) occur. Further, as described later, gasification of chlorine contained in waste and gasification of low-boiling heavy metals or reaction with chlorine occur. Occurs. _{H 2 O (liq) = H} 2 O (gas) ··· C p H q O r = r / 2CO 2 + q / nC m H n + (p-r / 2-qm / n) C ··· C _{m H n = n / 4CH 4} + {m- (n / 4)} C ··· CO + 1 / 2O 2 = CO 2 ··· here, H ₂ O (liq): water attached C _p in the waste H _q O _r: organics C _m H _n in waste: hydrocarbon gas produced by the decomposition of organic substances in waste C: carbides are supplied to the first zone CO: produced carbides in the first zone is combusted CO ₂ O ₂ : The oxygen-type reaction in the supporting gas blown from the secondary tuyere and / or the upper blowing lance is the dehydration heating of waste, and the high-temperature reducing gas supplied from the first zone. The sensible heat is used. Further, this reducing gas is supplied to the combustion supporting gas 7-2 and / or the upper blowing lance 24-1 injected from the secondary tuyere 5-2.
This is also performed by sensible heat generated when performing secondary combustion according to the reaction formula by the combustible gas 22 blown from the air. As a result, the organic matter in the waste is thermally decomposed into a hydrocarbon (however, represented as C in the formula and the formula) and hydrocarbon gas according to the formula and the formula. If necessary, auxiliary fuel is supplied from the secondary tuyere and / or the upper lance.

The blowing of the flammable gas may be carried out using only the secondary tuyere or only the upper blowing lance, whereby the dewatering and heating of the waste in the formula can be performed. However, if the secondary tuyere and the upper blowing lance are used at the same time, the combustion supporting gas can be uniformly blown into the second zone, so that the dewatering and heating of the waste can be efficiently performed.

The carbide obtained in this step moves to the first zone, and the hydrocarbon gas moves to the third zone.

In the second zone, the following sensible heat is generated by the sensible heat of the high-temperature reducing gas supplied from the first zone or in addition to the sensible heat generated during the secondary combustion according to the reaction formula. The reactions shown in Formulas -1 to -3 occur. The above-mentioned gasification of chlorine contained in the waste and gasification of heavy metals having a low boiling point or reaction with chlorine. That is, the chlorine contained in the waste is −1
And -2 to produce chlorine gas and hydrogen chloride gas. On the other hand, heavy metals having a low boiling point in wastes are gasified as they are by the formula (1), or chlorides of heavy metals having a low boiling point are generated as shown in the formulas (2) and (-3). In general, when chloride is used, it is very easy to evaporate. _{2Cl = Cl 2 (gas) ···} -1 2Cl + H 2 O (gas) = 2HCl (gas) ··· -2 M = M (gas) ··· -1 M (gas) + Cl 2 (gas) = MCl ₂ (gas) ··· -2 M (gas) + 2HCl (gas) = MCl ₂ (gas) + H ₂ ··· -3 where Cl: chlorine in waste M: low boiling point heavy metal in waste ( For example, Hg, Cd, P
b etc.) M (gas): gasification product of low-boiling heavy metals MCl ₂ (gas): chloride of low-boiling heavy metals In this step, if necessary, auxiliary materials (for example, Limestone, quicklime, etc.) to form a packed layer. That is, the waste is relatively densely packed. By forming such a packed layer of waste, the contact time between solid and gas when a high-temperature gas passes through the layer is prolonged, and thermal efficiency is improved.

The secondary combustion of the high-temperature reducing gas is performed by using the secondary combustion heat of the formula to promote the heating, controlling the thermal decomposition temperature of the organic substance to 800 to 1400 ° C., and having a low boiling point. This is for gasifying heavy metals.

The reason why the thermal decomposition temperature is set to 800 to 1400 ° C. is to promote gasification of organic matter by thermal decomposition and to completely gasify low-boiling heavy metals. Since the heat of secondary combustion is much larger than the heat of combustion (primary heat of combustion) in the above equation, it is possible to sufficiently supplement the heat necessary for dehydration / pyrolysis of waste and gasification of low-boiling heavy metals. it can. In addition, at this time, in order to suppress the sensible heat loss by reducing the amount of generated gas, and to suppress a decrease in calories of the generated gas,
It is preferable that the oxygen concentration in the supporting gas be 50% or more. Further, when the amount of generated gas is reduced, scattering of waste can be prevented and the concentration of low boiling heavy metals contained in dust can be increased. Therefore, the oxygen concentration in the combustion supporting gas is increased to 50% or more. Is preferred. In the third zone, the following formula and the reaction represented by the formula occur. In _{C m H n + m / 2O} 2 = mCO + n / 2H 2 ··· CH 4 + 1 / 2O 2 = CO + 2H 2 ··· Here, C _m H _n: hydrocarbon waste in the second zone is generated by thermal decomposition hydrogen gas CH _4: methane O ₂ to C _m H _n in the second zone is generated by thermal decomposition: the reaction of oxygen in these combustion assisting gas blown from 3 tuyeres and / or upper blowing lance first A gas (energy gas) containing CO and H ₂ as main components is obtained by a thermal decomposition reaction (gas reforming reaction) of the hydrocarbon gas supplied from the two zones. These reactions are carried out by the supporting gas 7-3 blown from the tertiary tuyere 5-3.
The reaction proceeds with the combustion supporting gas 22 blown from the upper blowing lance 24-1. If necessary, auxiliary fuel is supplied from the tertiary tuyere and / or the upper blowing lance.

The blowing of the supporting gas may be carried out using only the tertiary tuyere or only the upper blowing lance, whereby it is possible to cause the above formula and the reaction shown by the formula. However, if the tertiary tuyere and the upper blowing lance are used at the same time, the combustion supporting gas can be evenly and uniformly blown to the free board in the third zone, so that the reaction represented by the expression and the expression can be performed efficiently. be able to.

The reaction in the third zone is free board 1
The reaction is performed in six cavities. The reason why the reaction is performed in such a cavity is to smoothly perform a gas reforming reaction, which is a reaction between gases. The atmosphere temperature in the cavity is 800 to 1400
It is preferable to control the temperature to ° C., because the reforming reaction sufficiently proceeds. More preferably, it is 1000-1200 degreeC.

From the viewpoint of suppressing the formation of dioxins and their precursors such as chlorobenzene and chlorophenol, the ambient temperature is preferably 500 ° C. or higher, and furthermore, dioxins, chlorobenzene, chlorophenol and the like. 9 to completely decompose
The temperature is more preferably set to 00 ° C. or higher.

The oxygen concentration in the combustion supporting gas is preferably set to 50% or more. This is because the calorie of the recovered gas is increased so that the gas can be easily used in applications such as power generation in the next process. In the above-described example, a gasification and melting furnace provided with three-stage tuyeres and an upper blowing lance corresponding to each zone is used.
As described above, at least one tuyere may be provided. Since the supply of the supporting gas and the auxiliary combustion to the second zone and the third zone can be performed by the upper blowing lance, the first zone is provided.
This is because it is only necessary that one-stage tuyere be attached to a portion corresponding to the zone.

As described above, in the method for gasifying and melting waste according to the invention (2), the reaction in the first to third zones causes the energy gas containing CO and H ₂ as main components and the low-temperature gas. Collect dust containing boiling heavy metals, molten slag and molten metal. Therefore, at least one tuyere and an upper blowing lance are required. Furthermore, at least one of the tuyere and the upper blowing lance must be capable of independently injecting the supporting gas and the auxiliary fuel. The reason is as follows. It is assumed that the tuyere is attached to each zone.

The amount of C (carbide) involved in the reaction of the formula varies depending on the formula and the degree of progress of the reaction represented by the formula. In addition, if the type of waste changes, the formula and the amount of reaction products represented by the formula naturally change.
Therefore, the amount of the supporting gas blown from the primary tuyere must be determined independently of the other steps. The same applies to auxiliary fuel supplied as needed. Next, the amount of the supporting gas blown from the secondary tuyere and / or the upper lance is determined by the reaction formula,
Since the O amount is determined by the reaction equation, it is considered that the O amount is apparently linked to the amount of the supporting gas blown from the primary tuyere. However, in fact, it is not necessary to perform secondary combustion on all CO gas generated by the reaction formula. In the second zone, at least dehydration heating of adhering moisture in waste and thermal decomposition of organic matter in waste and low-boiling heavy metal Heat required for gasification is added, and the ambient temperature of the second zone is further increased to 800 to 1400.
It is only necessary to apply the heat necessary to maintain the temperature in ° C. Therefore, the amount of combustible gas from the secondary tuyere and / or the upper blowing lance greatly changes depending on the components contained in the waste. That is, the amount of the supporting gas blown from the secondary tuyere and / or the upper lance must also be determined independently. The same applies to auxiliary fuel.

The ratio of the supporting gas or auxiliary fuel blown from the secondary tuyere and the upper blowing lance is preferably in the range of the following formulas. This is because a synergistic effect cannot be exerted if the ratio is out of this range and either one is too small or too large.

[0037]

(Equation 1) The amount of the supporting gas blown from the tertiary tuyere and / or the upper blowing lance is determined by the reaction formula. Since the amount of C _m H _n and CH ₄ by-containing component in this case waste is changed, as may define its own also combustion supporting gas amount blown from 3 tuyeres and / or upper blowing lance I have to put it. The same applies to the auxiliary fuel.

The ratio of the supporting gas or auxiliary fuel blown from the tertiary tuyere and the upper lance is preferably in the range of the following formula, as in the case of the secondary tuyere and the upper lance. This is because a synergistic effect cannot be exerted if the ratio is out of this range and either one is too small or too large.

[0039]

(Equation 2) The blowing amount of the supporting gas and the amount of the auxiliary fuel to be supplied as necessary are determined as follows.

When the target of the treatment is, for example, general waste in which different kinds of wastes are mixed, since the component analysis is not usually performed before charging into the furnace, unknown components are burned in the furnace. Or thermal decomposition, and it is practically impossible to predict the amount of generated gas and its components.

Under such conditions, the level of the loaded waste (the top level of the raw material layer) is sequentially measured. This makes it possible to indirectly grasp the change in the thickness of the packed bed in the furnace (the packed bed of waste and the packed bed of carbide). That is, as the amount of combustion increases, the loading of the carbide packed layer formed in the first zone decreases, and the top level of the raw material layer decreases. Therefore, a predetermined raw material layer top level is determined empirically in advance, and then the supporting gas from the primary tuyere and the auxiliary fuel supplied as necessary are blown based on the vertical fluctuation of the raw material layer top level. The amount may be determined. As a raw material layer top level meter to be used, a sounding device known as a raw material layer top level meter inside a blast furnace in the field of steelmaking is suitable, but an RI (radioisotope) method or the like is generally effective. This method is known, and this method can be applied. By the way, since the packed bed of the waste formed in the second zone is present on the packed bed of the carbide formed in the first zone, the measured top level of the raw material layer is equal to the first and second zones. It appears as the sum of the respective changes in the zone. Therefore, it is necessary to distinguish the amount of change between the first zone and the second zone, but the change in the reaction in the second zone can be indirectly grasped by sequentially measuring the temperature change in the second zone. That is, in the second zone, heat necessary for at least dehydration heating of adhering water in waste, thermal decomposition of organic matter in waste and gasification of low-boiling heavy metals is added, and the atmospheric temperature of the second zone is set to 800 to Since it is only necessary to apply the heat necessary to maintain the temperature at 1400 ° C., the temperature change of the waste in the area of the second zone is sequentially measured, and if it decreases, it is judged that the heat is insufficient, and the secondary tuyere and And / or increasing the amount of the supporting gas from the upper blowing lance to increase the amount of CO to be subjected to secondary combustion (the amount of secondary combustion of CO generated by the reaction formula). Conversely, if the temperature rises, it can be determined that there is a thermal margin, so reduce the amount of the supporting gas from the secondary tuyere and / or the upper blowing lance to reduce the amount of CO to be secondary-combusted. I just need. The temperature change of the waste can be regarded as the temperature change of the second zone, and the temperature change of the second zone can be determined, for example, by installing a thermocouple on the surface of the lining brick of the second zone, Can be determined by measuring

As described above, the level measured by the raw material layer top level meter is used.
Values and the surface temperature of the lining brick in the second zone
By measuring, the support of the first zone and the second zone
The injection amount of reactive gas and auxiliary fuel to be supplied if necessary.
Each can be determined independently. In the third zone,
The ambient temperature at the exit of the second zone (freeboard side) is 80
If the temperature is maintained at 0 to 1400 ° C, hydrocarbons in exhaust gas, especially
Tar-like carbon number that causes troubles such as pipe blockage
Is 5 or more hydrocarbons (C_m H_n : M ≧ 5)
it can. Also known as dioxins and their precursors
For complete decomposition of lorobenzene, chlorophenol, etc.
is necessary. Therefore, the free board in the third zone is empty.
A thermometer is installed in the space and the temperature is measured sequentially,
When the temperature falls below 800 ° C., the third tuyere and / or
From the top blowing lance with supporting gas and, if necessary, auxiliary fuel
Just blow it. In particular, immediately after charging waste into the furnace
Is the top of the raw material layer in the second zone and the free
The temperature in the second zone and the
And hydrocarbons produced, judging from the temperature in zone 3
(C _m H_n : M ≧ 5) to decompose dioxins
Injection of supporting gas and auxiliary fuel if necessary
It is effective to do. Gasification melting of the invention of the above (4)
According to the method, without the use of expensive coke,
A series of processes of gasification melting, dehydration / pyrolysis and gas reforming
In one furnace and contains tar, dioxins, etc.
Clean exhaust gas can be obtained. In addition, exhaust gas
Although it contains dust containing low boiling heavy metals,
Dust removal equipment such as hot cyclone installed outside (dust collection
Means) to separate the dust and energy gas.
Can be released.

For collecting fine dust which is difficult to collect even with a hot cyclone, washing with water is effective. The dust separated and recovered by the hot cyclone or water treatment contains heavy metals having a low boiling point, and thus can be concentrated through a treatment step using an alkali or an acid. Known techniques can be applied to the treatment using the hot cyclone and the cleaning treatment using water.

[0044]

(Example 1) Using a vertical furnace (gasification and melting furnace) having the structure shown in FIG. The material was subjected to a gasification melting test. In addition, the dimension of each part of a vertical furnace, the number of tuyere and other attachment parts, and their arrangement are as follows. Dimensions Furnace diameter: 0.5m (furnace inner diameter after brick lining) Furnace height: 2.0m (however, height from furnace bottom to furnace top after brick lining) Height from furnace bottom to primary tuyere Height: 0.3 m Height from furnace bottom to secondary tuyere: 0.6 m Height from furnace bottom to tertiary tuyere: 1.6 m Upper lance outer diameter: 50 mmφ Upper lance hole: Center hole: 1 hole for pulverized coal + carrier gas injection 1 hole x 3φ x 0 degrees (= vertical direction) Side hole: for oxygen + nitrogen gas injection 3 holes x 5φ x 10 degrees (= 10 degrees inclined to vertical direction) Arranged around the center hole at 120 degree intervals Height from furnace bottom to lance tip: Standard 1.8 m (variable up and down) Position of thermocouple in second zone: 0.9 m (temperature of thermocouple in second zone) The position is the height of the thermocouple attached to the surface of the lining brick in the second zone from the bottom of the furnace.) Position of the thermocouple: 1.1 m (The position of the thermocouple in the third zone refers to the height of the thermocouple installed in the freeboard space from the bottom of the furnace.) Quantity Primary tuyere: 3 pieces 2 Next tuyere: 3 Tertiary tuyere: 3 Upper blowing lance: 1 Discharge port of molten slag and molten metal: 1 Sounding device (raw material layer top level meter): 1 Thermocouple in second zone: 3 thermocouples in the third zone: 3 arrangement Primary tuyere: equidistant every 120 degrees in the circumferential direction Secondary tuyere: equidistant every 120 degrees in the circumferential direction Tertiary tuyere: 120 degrees in the circumferential direction Top-blowing lance: Furnace center Molten slag and molten metal outlet: Furnace bottom end Sounding device: Between top-blowing lance and side wall Thermocouple in the second zone: Peripheral 120-degree equally-spaced Zone 3 thermocouples: equally spaced every 120 degrees in the circumferential direction The waste used in the above test is generally In three municipal solid waste (designated as Sample 4, 5 and 6), for each drying degree are different, 3408Kca per waste 1kg
1, 2518 kcal and 1628 kcal with a low heat generation reference. Table 1 shows the composition of these wastes. The size of the waste is 10-100m
m.

[0045]

[Table 1] The auxiliary materials (limestone) and auxiliary fuel (pulverized coal) used were the same as those used in Example 1 and had the compositions shown in Tables 2 and 3, respectively. In addition, limestone is 10-50
mm, and the pulverized coal was a previously dried powdery powder of 1 mm or less.

[0046]

[Table 2]

[Table 3] The combustible gas blown from the primary tuyere, the secondary tuyere, the tertiary tuyere and the upper blowing lance is a gas based on oxygen and slightly mixed with nitrogen. Table 4 shows their flow rates (the flow rates of oxygen and nitrogen, respectively). In the table,
Primary means primary tuyere. The same applies to the second and third orders.

[0047]

[Table 4] Table 4 shows the running conditions (steady state) of this test.
For each of Samples 4, 5, and 6, the following (1) to
It was determined according to the procedure of (8). In the test, first, sample 4 was charged into the furnace and treated under the conditions shown in the column of sample 4 in Table 4, and then changed to sample 5 and shown in the column of sample 5. The processing was performed under the conditions described above, and the processing was further performed under the conditions shown in the column of Sample 6 by changing to Sample 6. The processing time of each sample was 24 hours, and the amount of waste during that time was 1 ton (3 tons in total) for each sample. (Procedure for Setting Processing Conditions) (1) The composition of the initially charged waste (here, indicating the sample 4) was determined by previously analyzing the composition. This is necessary in order to determine the approximate value of the oxygen injection amount serving as a base, and also to determine the amount of limestone to be charged as a slag-making material. In addition, the amount of limestone is the slag basicity that the fluidity of molten slag is considered to be the best (that is,
1.0). (2) Preheat the gasification and melting furnace with a burner, etc.
Waste was ignited even at room temperature where the combustion supporting gas blown from the tuyere was not heated. (3) Waste is charged into the furnace and the sounding height is 0.9
１．１1.1 m. (4) After gradually flowing oxygen gas from the primary tuyere, the outlets for the molten slag and the molten metal were opened. (5) During the test, since the top level of the raw material layer decreased with the burning of the waste, the raw materials (waste and limestone) were sequentially charged so as to maintain the level in the range of 0.9 to 1.1 m. In the steady state, the input speed of waste is always 40 kg /
h. (6) The temperature measured by the thermocouple attached to the surface of the lining brick in the second zone and the thermocouple attached to the freeboard space in the third zone is always 800 to 1
The amount of oxygen gas blown from the primary tuyere, secondary tuyere, tertiary tuyere and upper blowing lance was adjusted so as to maintain 400 ° C.

That is, the unloading speed is high and the second
When the temperature of the zone and the zone of the third zone exceeded 1400 ° C., the oxygen gas from the primary tuyere was reduced.
Conversely, if the temperature of the second zone is lower than 800 ° C., 2
Oxygen gas was blown from the next tuyere and upper blowing lance. When the temperature of the third zone was lower than 800 ° C., oxygen gas was blown from the third tuyere and the upper lance. (7) The temperature of the molten slag and the molten metal is measured, and when the temperature falls below a predetermined temperature of 1400 to 1600 ° C,
Pulverized coal was blown from the primary tuyere. When Sample 6 corresponds to this case and the amount of heat generated by the waste itself is small, it is necessary to supply auxiliary fuel from the primary tuyere.
Also, pulverized coal was blown from the secondary tuyere and the upper lance. (8) By repeating the above (5) to (7), it was possible to derive the optimum amount of the supporting gas and auxiliary fuel to be blown (that is, the amount shown in the condition column of Table 4). Here, nitrogen was blown in as an amount of about 1/10 of oxygen, but if the oxygen concentration was ≧ 50%, it was possible to adequately cope with it. In addition, even when the sample was changed (from sample 4 to sample 5 and from sample 5 to sample 6), it was possible to appropriately cope with the case.

Table 5 shows the results (actual results) obtained in the above tests.
Shown in The unit is the amount per ton of waste. As indicated, CO and H ₂ containing almost no dioxins
A high-calorie energy gas containing as a main component (denoted as exhaust gas in the table) and dust enriched with low-boiling heavy metals such as mercury, cadmium and lead could be recovered. The energy gas and dust were discharged outside the furnace through a gas outlet through a duct, and then separated and recovered by a hot cyclone.

[0050] Also, at a concentration hydrocarbon entirely negligible, such as hydrocarbons in the exhaust gas, C _m H _n is a cause of particular cause pipe blockages (m ≧ 5). Further, the concentration of hydrogen chloride in the exhaust gas was high because the temperature in each zone in the gasification and melting furnace was increased from that in Example 1 to promote gasification. Since it can be sufficiently removed by a known technique (for example, water treatment of exhaust gas), there is no problem in the process.

Further, a molten metal and a molten slag mainly containing valuable metals such as iron and copper could be recovered.
The molten metal and the molten slag were discharged from the slag outlet to the outside of the furnace, and then separated and collected into a metal component and a slag component.

In the second embodiment in which the tuyeres of the first to third zones and the upper blowing lance are used at the same time, the combustion supporting gas can be uniformly and uniformly blown into each zone in the gasification and melting furnace. Therefore, as compared with Examples 2 and 3 described below,
The superiority was recognized for the following items.

Reduction of oxygen consumption Reduction of auxiliary fuel (pulverized coal) consumption Reduction of dust amount Concentration of low-boiling heavy metals in dust Reduction of dioxins and hydrocarbon gas in energy gas

[0054]

[Table 5] (Example 2) Using the same vertical furnace (gasification melting furnace) as the furnace used in Example 1, and the same three kinds of wastes (samples 4, 5, and 6), a primary tuyere and an upper blowing lance The waste gasification and melting test was performed using only the sample.

Table 6 shows the test conditions and Table 7 shows the test results (actual results). The unit is the amount per ton of waste. As displayed, (identified in the Table, the exhaust gas and display) high caloric energy gas mainly composed of CO and H ₂ containing little dioxins and mercury, low-boiling heavy metals such as cadmium and lead are concentrated Dust could be recovered. The energy gas and the dust were discharged outside the furnace through the gas outlet, and then separated and collected through a hot cyclone.

[0056] Also, at a concentration hydrocarbon negligible, such as hydrocarbons in the exhaust gas, it is responsible for particular cause pipe blockages _{C m H n (m ≧ 5} ). Further, the concentration of hydrogen chloride in the exhaust gas was high because the gasification was promoted by raising the temperature of each zone in the gasification and melting furnace, but it can be sufficiently removed by a known exhaust gas treatment technology. No problem.

Further, a molten metal and a molten slag mainly containing valuable metals such as iron and copper could be recovered. The molten metal and the molten slag were discharged from the slag outlet to the outside of the furnace, and then separated and collected into a metal component and a slag component.

In the third embodiment using the upper blowing lance,
Since the combustion supporting gas could be relatively uniformly blown into each zone in the gasification and melting furnace, the lance of Example 2 was compared with the following Example 4 (when no upper blowing lance was used). The superiority was recognized for the items listed at the end of.

[0059]

[Table 6]

[Table 7] (Example 3) Using the same vertical furnace (gasification melting furnace) as the furnace used in Example 1, and the same three kinds of wastes (samples 4, 5, and 6), without using an upper blowing lance, 1 A waste gasification melting test was performed using only the next tuyere to the third tuyere.

Table 8 shows the test conditions and Table 9 shows the test results (actual results). The unit is the amount per ton of waste. As displayed, (identified in the Table, the exhaust gas and display) high caloric energy gas mainly composed of CO and H ₂ containing little dioxins and mercury, low-boiling heavy metals such as cadmium and lead are concentrated Dust could be recovered. The energy gas and the dust were discharged outside the furnace through the gas outlet, and then separated and collected through a hot cyclone.

[0061] Also, at a concentration hydrocarbon negligible, such as hydrocarbons in the exhaust gas, it is responsible for particular cause pipe blockages _{C m H n (m ≧ 5} ). Further, the concentration of hydrogen chloride in the exhaust gas was high because the gasification was promoted by raising the temperature of each zone in the gasification and melting furnace, but it can be sufficiently removed by a known exhaust gas treatment technology. No problem.

Further, a molten metal and a molten slag mainly containing valuable metals such as iron and copper could be recovered. The molten metal and the molten slag were discharged from the slag outlet to the outside of the furnace, and then separated and collected into a metal component and a slag component.

[0063]

[Table 8]

[Table 9]

According to the present invention, if the waste gas is incinerated in accordance with the method of the present invention using the gasification and melting furnace of the present invention, the organic matter contained in the waste is gasified and recovered as an energy gas, and the waste gas is recovered. Can be recovered as molten slag and molten metal, respectively.
As a result, it is possible to reduce the cost of landfilling general waste and industrial waste, which is a problem at present, and to use the generated by-product gas as a fuel for power generation.

When the reaction temperature in the gasification and melting furnace is increased, gasification is promoted, and it becomes possible to recover heavy metals having a low boiling point.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing the configuration of another example of the waste gasification and melting furnace of the present invention.

[Explanation of symbols]

1: Gasification and melting furnace body 2: Refractory brick 3-1: Gas discharge port 3-2: Gas discharge duct 4: Exhaust gas 5-1: Primary tuyere 5-2: Secondary tuyere 5-3: Tertiary Tuyere 6-1: Auxiliary fuel to be blown into primary tuyere 6-2: Auxiliary fuel to be blown into secondary tuyere 6-3: Auxiliary fuel to be blown into tertiary tuyere 7-1: Fuel support to be blown into primary tuyere 7-2: Combustion gas blown into secondary tuyere 7-3: Combustion gas blown into tertiary tuyere 8: Flow of molten slag and molten metal 9: Discharge port of molten slag and molten metal 10 : Pusher 11-1: Waste inlet 11-2: Hopper 12: Waste 13: Molten slag and molten metal 14: Packing layer mainly composed of carbide 15: Packing layer mainly composed of waste 16: Free board 17 : Sounding device (raw material layer top level meter) 19: Temperature converter (A device for converting a signal of a thermocouple into a temperature) 20: a thermocouple provided on the surface of the lining brick in the second zone 21: a thermocouple provided in a free board space of the third zone 22: a combustion supporting gas 23: Auxiliary fuel 24-1: Upper blowing lance 24-2: Lance lifting device 25: Hot cyclone 26: Energy gas 27: Dust

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10J 3/00 ZAB C22B 9/02 C22B 1/00 601 F23G 5/44 ZABZ 7/00 F23J 1/08 9 / 02 F27B 1/08 A F23G 5/44 ZAB 1/16 F23J 1/08 1/26 F27B 1/08 F27D 17/00 104K 1/16 B09B 3/00 ZAB 1/26 303K F27D 17/00 104 5 / 00 M (72) Inventor Takaiku Yamamoto 4-5-33 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Inside Sumitomo Metal Industries, Ltd. (72) Hirotaka Sato 4-5-33 Kitahama, Chuo-ku, Osaka City, Osaka Sumitomo Metal Industry Co., Ltd.

Claims (2)

[Claims] 1. Burning waste, gasifying organic matter in the waste and recovering it as an energy gas, and gasifying low-boiling heavy metals in the waste to recover it as dust accompanying the energy gas. A vertical waste gasification and melting furnace for recovering ash and metals in waste as a melt, a waste loading inlet for charging the waste at the top, and gas and dust generated. A gas discharge port to be discharged and dust collecting means connected to the gas discharge port via a gas discharge duct; a discharge port for molten slag and molten metal at a lower portion; A tuyere capable of independently injecting a supporting gas and an auxiliary fuel between a metal outlet and a tuyere, which burns and gasifies carbides generated by dehydration and pyrolysis of waste. Having at least one stage of tuyere in the height direction including the tuyere, and having an upper blowing lance at the upper part of the furnace capable of injecting a combustible gas and an auxiliary fuel which can be raised and lowered into the furnace. And a means for measuring the level of the charged waste, a means for measuring the temperature in the vicinity of the tuyere in the middle stage, and a means for measuring the temperature of the atmospheric gas in the upper part of the furnace. Gasification and melting furnace for waste. 2. A method for gasifying and melting wastes using the waste gasification and melting furnace according to claim 1, wherein the wastes charged into the furnace from a waste charging inlet are: the reaction in each zone, and the dust including energy gas and low-boiling heavy metals mainly containing CO and H _2, and molten slag and the molten metal, is recovered from the gas discharge port provided the former furnace upper A gasification and melting method for waste, comprising separating into energy gas and dust, and collecting the latter from a discharge port of molten slag and molten metal provided at a lower part of the furnace. [First Zone] A supporting gas and, if necessary, auxiliary fuel are blown from the lower tuyere to burn and gasify the carbide generated in the second zone to generate a reducing gas, and to reduce ash contained in the carbide. The metals are melted into molten slag and molten metal. [Second Zone] The supporting gas and, if necessary, auxiliary fuel are blown from the tuyere in the middle stage and / or the upper blowing lance,
The reducing gas generated in the zone is secondarily burned, and the waste charged from the waste loading inlet is dehydrated and heated to thermally decompose into carbide and hydrocarbon gas, while gasifying low-boiling heavy metals. [Third Zone] The supporting gas and, if necessary, auxiliary fuel are blown from the upper tuyere and / or upper blowing lance,
The hydrocarbon gas generated in the zone is thermally decomposed to CO and H ₂
As the main component, and gaseous low-boiling heavy metals as dust.