JP3339419B2 - Gasification and melting furnace for waste and gasification and melting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a gas (hereinafter referred to as "waste") which can be used as a fuel by converting general waste and industrial waste (hereinafter simply referred to as waste).
Energy gas) as well as a waste gasification and melting furnace and method for recovering ash and metals contained in these wastes as molten slag and molten metal, respectively. The present invention relates to a waste gasification and melting furnace and a gasification and melting method for the waste, which can prevent the wear of the refractory.

[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, in recent years, it is extremely difficult to secure landfill sites, and the incineration method generally used so far has been reviewed. In addition, incineration ash generated after incineration of waste contains a large amount of heavy metals, and therefore, it is required to perform chemical treatment or high-temperature melting treatment for the purpose of preventing elution thereof.

[0003] Since general waste and industrial waste contain various substances, a gasification and melting method capable of flexibly coping with various wastes has been spotlighted. Especially if this method is used, waste can be converted into molten slag,
It has the feature that heavy metals in waste can be contained in slag and made harmless.

[0004]

In the gasification and melting system, the combustible, ash, iron, etc. in the waste are effectively used to reduce the landfill cost of the waste and to reduce the by-product gas generated. There was a need for a method that utilizes latent heat.

The present invention aims to reduce the cost of landfilling waste by effectively utilizing combustibles, ash, iron, etc. in general and industrial wastes, and to utilize the by-product gas generated as fuel for power generation. In addition, it is intended to provide a gasification melting furnace and a gasification melting method capable of economically treating a waste by suppressing wear of a lining refractory and a tuyere tip which becomes a problem when gasifying and melting waste at a high temperature. is there.

[0006]

Means for Solving the Problems The inventors of the present invention have repeated the tests in a gasification melting furnace at a practical level, and as a result, the following (A)
~ (G) was obtained.

(A) When water-cooled using a jacket or the like so as to surround the steel shell on the back side of the refractory lining of the gasification melting furnace, the refractory is cooled, and the waste filled in the furnace adheres. In addition, the molten slag or the like solidifies on the surface of the refractory to form a protective layer of the refractory.

(B) Since the temperature is high near the tip of the side blowing tuyere, the slag and the like remain in a molten state and the above-mentioned protective layer of the refractory lining cannot be formed. When the protective layer is moved to the core side, the protective layer is easily formed.

(C) However, if the thickness of the protective layer is excessively increased, the waste treatment zone is narrowed. Therefore, it is necessary to control an appropriate thickness range of the protective layer.

(D) In order to manage the appropriate thickness range, a means for measuring the temperature of the outer periphery of the tuyere is installed at the above-mentioned side-blowing tuyere, and based on the temperature measurement results, the amount of cooling water and the side-blowing tuyere are measured. What is necessary is just to decide the appropriate position.

(E) For example, one thermocouple is installed on each of the refractory side and the core side at the outer periphery of the tuyere, and if the temperature on the refractory side is in the range of 300 to 500 ° C., the lining refractory is protected. The temperature range on the core side is 90
If it is in the range of 0 to 1100 ° C., it is possible to avoid melting the tuyere tip.

(F) The position of the side-blowing tuyere is controlled so that the temperature on the refractory side falls within the range of 300 to 500 ° C, and the temperature on the core side is cooled so as to fall within the range of 900 to 1100 ° C. It is good to control the amount of water.

(G) If a large number of temperature measuring means are provided in the tuyere length direction, it is possible to finely suppress the wear of the refractory lining and the tip of the tuyere.

The present invention has been made based on the above findings, and the gist is as described in the following (1) to (3).

(1) Burning the waste to gasify the organic matter in the waste and recovering it as energy gas;
A waste gasification / melting furnace for recovering ash and incombustibles such as metals in waste as molten slag and molten metal, wherein the refractory lined in the furnace is cooled from a steel shell on the back side. It has a device, and has a waste loading inlet for loading the waste in the center in the height direction, a gas outlet for discharging generated gas at the upper part, and a discharge port for molten slag and molten metal at the lower part. And a supplementary fuel is injected between the gas discharge port and the waste loading port when the supporting gas and the amount of heat are insufficient.
It has a side-blowing tuyere with a water-cooled structure at the stage, and an upper-blowing lance with a water-coolable structure that can inject auxiliary fuel when the amount of heat is insufficient at the upper part of the furnace, and a waste loading port. Between the discharge ports of the molten slag, there is a two-stage water-cooled side-blowing tuyere that blows auxiliary fuel when the amount of calcining gas or heat is insufficient. A gasification and melting furnace for wastes, comprising a drive unit for moving a tip end of a tuyere in a horizontal direction between a refractory lined with one core and a core.

(2) At least two means for measuring the temperature of the outer peripheral portion of the horizontally blown tuyere described in the above (1) are provided in the longitudinal direction of the tuyere. Gasification and melting furnace for waste.

(3) Using the waste gasification and melting furnace described in (2) above, based on the temperature of the outer peripheral portion of the side-blowing tuyere,
Along with determining the moving position of the tip of the side blowing tuyere,
A method for gasifying and melting waste, comprising determining a cooling water amount of the side-blowing tuyere.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The inside of the gasification melting furnace of the present invention can be divided into three zones according to the reaction that takes place.

From the bottom of the furnace, a first zone where gasification and melting of carbides are sequentially generated, a second zone where dehydration / pyrolysis of waste and gasification of low-boiling heavy metals are performed, and pyrolysis of hydrocarbons (also referred to as reforming). ) And a dust containing low-boiling heavy metals together with a gas (also referred to as an energy gas) and discharged outside the furnace.

A first tuyere, a second tuyere, a third tuyere, and a third tuyere capable of independently injecting a supporting gas and an auxiliary fuel required for the reaction into the first, second and third zones. Upper lances are installed correspondingly. 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. Along with
Ash and valuable metals contained in these wastes can be efficiently recovered as molten slag and molten metal, respectively. Moreover, it is possible to avoid the hanging of the shelf and the occurrence of blow-through, which are peculiar to the vertical furnace.

Referring to FIG. 1, a configuration example and a method of an apparatus for carrying out the present invention will be described.

FIG. 1 is a schematic vertical sectional view showing the structure of an example of the waste gasification and melting furnace of the present invention. As shown
The waste gasification and melting furnace 1 is lined with a refractory lining 2,
And a waste loading inlet 1 for loading a waste 12 at the top.
1-1 and a gas discharge port 3-1 for discharging generated energy gas (hereinafter, also referred to as exhaust gas) and dust. The hopper 11 is installed at the waste loading port 11-1.
-2 and a pusher 10 are attached, and a gas exhaust duct 3-2 for collecting energy gas and dust 4 is attached to the gas exhaust port 3-1. A slag discharge port 28 for discharging molten slag 8 (hereinafter, also simply referred to as slag) and a metal discharge port 29 for discharging molten metal 9 (hereinafter, also simply referred to as metal) are provided at the lower part of the furnace. The slag and the molten metal are provided via an overhang portion 13 having a space portion in which the slag and the molten metal can be temporarily accumulated before being discharged out of the furnace. A weir 14 is provided at the overhang. Further, a cooling device 30 is provided so as to pass through the cooling water 19 so as to surround the steel shell on the back side of the refractory lining.

Between the gas discharge port 3-1 and the slag discharge port 28, a fuel supporting gas and / or an inert gas, and in the height direction in which auxiliary fuel can be blown when the calorific value is insufficient, is provided. A side-blowed tuyere is provided in stages.

In order from the bottom of the furnace, the combustible gas 7-1 and the auxiliary fuel 6-1 are blown into the first zone mainly composed of the waste containing carbide generated by dehydrating, heating and pyrolyzing the waste. (Hereinafter, primary tuyere, primary side-blow tuyere 5)
-1) to dehydrate and thermally decompose waste.
Tuyere (hereinafter referred to as secondary tuyere, 2) for injecting the combustible gas 7-2 and the auxiliary fuel 6-2 into the second zone mainly composed of waste.
A layer 15 mainly composed of wastes and carbides, which is composed of a next side tuyere 5-2, and a tuyere (hereinafter referred to as a tertiary tuyere) for blowing the combustible gas 7-3 and the auxiliary fuel 6-3. 3
Freeboard 1 consisting of the next horizontal tuyere 5-3)
6.

Cooling water 19 is passed through each of the primary to tertiary tuyeres. For example, each tuyere of the primary tuyere and the secondary tuyere is provided with a tuyere driving device 20-1 for moving the tuyere in the horizontal direction. At the outer periphery of the tuyeres of the primary tuyere and the secondary tuyere, a thermocouple 31 lining the refractory side in the length direction is provided.
1, a thermocouple 31-2 on the core side is provided.

To reduce the viscosity of the molten slag and smoothly discharge it from the discharge port 28, limestone is charged together with the waste.

The upper part of the waste gasification and melting furnace 1 is provided with an upper blowing lance 17 through which auxiliary fuel can be blown when the calorific value is insufficient, and a lance in a vertical direction (in FIG. Lifting device 20-2 for moving
There is. Cooling water 19 passes through the upper blowing lance 17.

The supporting gas is a gas such as pure oxygen or air containing oxygen, and the auxiliary fuel is a solid fuel such as pulverized coal, a liquid fuel such as heavy oil, a gas fuel such as LPG or LNG. is there.

Further, at the upper part of the furnace, a waste layer top level meter 21 for measuring the position of the input waste in the furnace (hereinafter also referred to as a waste layer top level) is provided. On the furnace side wall, a thermocouple 23 provided on the surface of the refractory lining, a thermocouple 24 for measuring the temperature of the atmospheric gas (gas temperature of the free board 16) in the upper part of the furnace, and signals of these thermocouples Is converted to a temperature.

In this gasification and melting furnace, the horizontal tuyere is divided into three stages in the height direction of the furnace, and a driving device is provided at least at one tuyere, and a means capable of measuring the temperature of the outer periphery of the tuyere is provided. The reason for having at least two in the length direction, the reason for providing an upper blowing lance with an elevating device, the reason for cooling each tuyere and the lance with cooling water, and providing a cooling device outside the refractory lining The reason will be described below.

In the first zone, a reaction represented by the following equation occurs. C + 1 / 2O ₂ = CO where C: carbide supplied from the second zone O ₂ : oxygen in the supporting gas blown from the primary tuyere This reaction is formed in the second zone 7-1, the combustible gas 7-1 in which the falling carbide is injected from the primary tuyere 5-1
The carbides are converted to combustion gas by the reaction of burning
It becomes a reducing gas mainly composed of CO at a temperature of 0 ° C. or higher.
In addition, the ash (inorganic oxide) and valuable metals contained in the carbide are melted by the sensible heat to form molten slag and molten metal. When the amount of heat is insufficient, the auxiliary fuel 6-1 is supplied from the primary tuyere 5-1.

The generated reducing gas moves to the second zone, and the molten slag and the molten metal are recovered from the outlet at the bottom of the furnace.

The reason why the waste is dehydrated and thermally decomposed in the second zone to produce a carbide, and the carbide is gasified and melted in the first zone is that the two-stage separation of the carbide is This is because heat promotion and suppression of heat loss from the molten slag and the molten metal can be effectively performed.

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 reduced to 50% by volume (hereinafter referred to as “%
Means volume%) or more, and if necessary, auxiliary fuel is blown.

In order to smoothly discharge the molten slag 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 the primary blades are discharged. Powder limestone is blown from the mouth as slag-making material,
It is preferred to reduce the viscosity of the slag.

In the second zone, the reactions represented by the following equations (1) to (3) occur. The reaction of the formula is a dehydration gasification operation of waste, and is performed by sensible heat of a high-temperature reducing gas supplied from the first zone. This reducing gas is used for secondary tuyere 5-
2 and / or the supporting gas 18 blown from the upper blowing lance 17,
It is also performed by sensible heat generated when performing secondary combustion according to the reaction formula.

[0037] These sensible heat, the organic matter in the waste carbide according to the equation and formula (wherein, shown as C in Formula) and pyrolyzing the hydrocarbon gas (C _m H _n).
If necessary, auxiliary fuel is supplied from the secondary tuyere and / or the upper lance. Carbides obtained in this step to the first zone, a hydrocarbon gas (C _m H _n) is shifted respectively to the third zone.

In the second zone, the following formulas (-1) to (-) are used due to the sensible heat of the high-temperature reducing gas supplied from the first zone and the sensible heat generated during the secondary combustion in the formula
The reaction shown in Equation 3 occurs. The reactions of formulas -1 and -2 are reactions in which chlorine in waste is gasified to generate chlorine gas and hydrogen chloride gas. Furthermore, low-boiling heavy metals in wastes are themselves gasified by the formula -1 or
Alternatively, a low-boiling heavy metal chloride is produced as shown in formulas -2 and -3. Generally, when chloride is formed, it is very easy to evaporate.

[0039] _{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 ··· 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 H ₂ O (liq): adhering moisture in waste C _p H _{q Or} : organic matter in waste C _m H _n : waste Hydrocarbon gas generated by decomposition of organic matter in the inside C: Carbide supplied to the first zone CO: CO O ₂ generated by burning of carbide in the first zone: From secondary tuyere and / or upper blowing lance Oxygen in the injected supporting gas Cl: Chlorine in waste M: Low boiling point heavy metal in waste For example, metal such as Hg, Cd and Pb M (gas): Gasification product of the above low boiling point heavy metal MCl ₂ (gas): Chloride of the above-mentioned low-boiling heavy metal In this step, by adding auxiliary materials (eg, limestone, quicklime, etc.) to the waste charged into the furnace, the waste is densely packed. Good to put. By forming a waste layer densely packed with waste, the contact time between solid and gas when a high-temperature gas passes through the layer is increased, and the thermal efficiency is improved.

The reason for secondary combustion of the high-temperature reducing gas using the secondary combustion heat of the equation is that the temperature for the thermal decomposition of organic substances and the temperature for the gasification of heavy metals having a low boiling point are 800-1.
This is because it is necessary to control the temperature to 400 ° C. This secondary combustion heat is much larger than the combustion heat (primary combustion heat) in the above formula, and is sufficient for replenishing the heat required for dehydration / pyrolysis of waste and gasification of low-boiling heavy metals. The oxygen concentration in the supporting gas is preferably set to 50% or more. The reason is that the amount of generated gas is reduced to suppress sensible heat loss, the calorie of generated gas is reduced, and the amount of generated gas is reduced to prevent scattering of waste and low boiling heavy metals contained in dust. This is because the concentration of the compound can be increased.

The reason why the secondary tuyere and the upper lance may be used in combination with the supporting gas is that the above-mentioned effect of the second zone can be obtained even with the secondary tuyere or the upper lance. However, by simultaneously using the secondary tuyere and the upper blowing lance, the combustion supporting gas can be uniformly blown into the second zone, so that the secondary combustion efficiency increases synergistically.

In the third zone, the following formula and the reaction represented by the formula occur. These reactions are thermal decomposition reactions (also referred to as gas reforming reactions) of hydrocarbon gas supplied from the second zone, and an energy gas containing CO and H ₂ as main components is obtained. These reactions proceed by the reaction with the supporting gas 7-3 blown from the tertiary tuyere 5-3 and / or the supporting gas 18 blown from the upper blowing lance 17. When the amount of heat is insufficient, auxiliary fuel is supplied from the tertiary tuyere and / or the upper lance.

C _m H _n + m / 2O ₂ = mCO + n / 2H ₂ ··· CH ₄ + ／ O ₂ = CO + 2H ₂ ··· where C _m H _n : Waste is thermally decomposed in the second zone. the produced hydrocarbon gas CH _4: methane O ₂ to C _m H _n in the second zone is generated by thermal decomposition: oxygen in the oxidizing gas blown from 3 tuyeres and / or upper blowing lance the first The reaction in the three zones is performed by the free board 16, and the reason for causing the reaction in such a cavity is to smoothly advance a gas reforming reaction, which is a reaction between gases.
Controlling the atmosphere temperature in the cavity to 800 to 1400 ° C. is preferable because the reforming reaction sufficiently proceeds. In order to suppress the production of dioxins and their precursors such as chlorobenzene and chlorophenol, the ambient temperature should be 9
The temperature is preferably set to 00 ° C. or higher. More preferably, 10
The optimum temperature is from 00 to 1200 ° C.

The oxygen concentration in the supporting gas is preferably set to 50% or more as described above. The reason for this is to increase the calorie of the recovered gas so as to make it easier to use it for applications such as power generation in the next process. In order to suppress the production of dioxins and their precursors such as chlorobenzene and chlorophenol, the ambient temperature is preferably 900 ° C. or higher.

The reason why the combustible gas may be used in combination with the secondary tuyere and the upper lance is that the effect of the second zone can be obtained even with the secondary tuyere or the upper lance as described above. Although it is possible, by simultaneously using the secondary tuyere and the upper blowing lance, the combustion supporting gas can be uniformly blown into the second zone uniformly, so that the secondary combustion efficiency increases synergistically.

As described above, in the method of the present invention, the first
By the reaction in the zone to the third zone, the dust containing the energy gas mainly composed of CO and H ₂ and the low-boiling heavy metal, the molten slag and the molten metal are recovered. Therefore, three stages of primary to tertiary tuyere and upper lance are required.

Further, the side blowing tuyere and the upper blowing lance of each stage must be capable of independently blowing the supporting gas and the auxiliary fuel. The reason is,
It is as follows.

In the case of the primary tuyere, the amount of the carbide (C) involved in the reaction of the formula varies depending on the formula and the degree of progress of the reaction represented by the formula.
This is because, naturally, the formula and the amount of the reaction product represented by the formula also change, so that a device configuration that can independently blow the amounts of the supporting gas and auxiliary fuel blown from the primary tuyere is preferable.

The amount of the supporting gas blown from the secondary tuyere and / or the upper blowing lance is determined by the reaction formula.
Since the amount is determined by the reaction formula, it is considered that the amount is apparently linked to the amount of the supporting gas blown from the primary tuyere.
However, actually, all of the CO gas generated by the reaction formula is 2
There is no need to perform subsequent combustion, and in the second zone, at least heat required for dehydration and heating of adhering moisture in waste, heat decomposition of organic matter in waste and gasification of low-boiling heavy metals are added,
Further, it is only necessary to apply heat necessary to maintain the atmosphere temperature in the second zone at 800 to 1400 ° C., and the amount of the flammable gas from the secondary tuyere and / or the upper blowing lance depends on the components contained in the waste. Greatly changed by the secondary tuyere and / or
Alternatively, it is preferable to use a device configuration in which the amounts of the supporting gas and auxiliary fuel blown from the upper blowing lance can be blown independently.

When the secondary tuyere and the upper lance are used at the same time, the distribution ratios of the supporting gas and the auxiliary fuel are as follows:
Secondary tuyere / top blowing lance = 0.1 to 10 is preferred. This is because a synergistic effect cannot be exerted if one of them is too small or too large.

[0051] 3 tuyeres and / or combustion supporting gas amount blown from the top blowing lance is determined in Scheme and, since the amount of C _m H _n and CH ₄ by-containing compounds in the waste varies, 3 This is because an apparatus configuration capable of independently blowing the amount of the supporting gas and auxiliary fuel blown from the next tuyere and / or the upper blowing lance is preferable.

When the tertiary tuyere and the upper lance are used at the same time, the distribution ratios of the supporting gas and the auxiliary fuel are as follows:
Third tuyere / upper lance = 0.1 to 10 is preferred. This is because a synergistic effect cannot be exerted if one of them is too small or too large.

The amount of auxiliary fuel to be supplied when the amount of blowing the supporting gas and the amount of heat are insufficient are determined as follows.

When the object to be treated is, for example, general waste mixed with different kinds of waste, component analysis is not usually performed before charging into the furnace, so that 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 top level of the loaded waste is measured sequentially. This makes it possible to indirectly grasp the change in the top level of the waste layer in the furnace. That is, as the amount of combustion of the carbide formed in the first zone increases, the unloading proceeds, and the top level of the waste decreases. Therefore, the top level of the predetermined waste is determined empirically in advance, and the amount of the combustion supporting gas from the primary tuyere and the amount of heat are insufficient based on the vertical fluctuation of the top level of the waste thereafter. In this case, the amount of auxiliary fuel to be supplied may be determined.

As a waste layer top level meter to be used, a sounding device known as a waste layer top level meter inside a blast furnace in the field of steelmaking is suitable, but an RI (radioisotope) system or the like is also generally used. It is known as an effective method.

Since there is a layer of waste formed in the second zone above the layer of carbides combusted in the first zone, the measured top level of the waste is between the first zone and the first zone. It appears as the sum of the respective changes in the two zones.

The change in the state of the reaction in the second zone can be indirectly grasped by sequentially measuring the temperature change in the second zone. In the second zone, heat required for at least dehydration gasification of adhering moisture 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 1400 ° C. In order to perform the operation of applying the heat held in the second zone, the temperature change of the waste in the area of the second zone is sequentially measured, and if it is less than 800 ° C., it is determined that the heat is insufficient, and the secondary tuyere and / or An operation is performed to increase the amount of the supporting gas from the upper blowing lance to increase the amount of CO to be subjected to the secondary combustion (the amount of the secondary combustion of the CO generated by the reaction formula). If the temperature exceeds 1400 ° C., it can be determined that there is a thermal margin, so that the amount of the supporting gas from the secondary tuyere and / or the upper blowing lance is reduced and the CO that is subjected to secondary combustion is reduced.
Perform the operation to reduce the volume.

The temperature change in the second zone can be determined, for example, by installing a thermocouple near the surface of the refractory lining in the second zone and measuring the surface temperature.

As described above, by sequentially measuring the level value by the waste layer top level meter and the surface temperature of the refractory lining in the second zone, the combustion supporting gas and the calorific value in the first and second zones are determined. In the case of a shortage, the amount of auxiliary fuel to be supplied can be independently determined.

In the third zone, if the ambient temperature at the outlet of the second zone (on the free board side) is maintained at 800 to 1400 ° C., hydrocarbons in the exhaust gas, especially tar and the like, which may cause troubles such as pipe blockage. All hydrocarbons having 5 or more carbon atoms (C _m H _n : m ≧ 5) can be decomposed. It is also necessary for complete decomposition of dioxins and their precursors such as chlorobenzene and chlorophenol.

Therefore, a thermometer is installed in the free board space of the third zone and its temperature is measured successively. When the temperature is lower than 800 ° C., the fuel is supplied from the tertiary tuyere and / or the upper blowing lance. A supplementary fuel may be injected when gas and heat are insufficient. In particular, immediately after the waste is charged into the furnace, the temperature at the top of the waste layer in the second zone and the temperature at the free board in the third zone drop sharply. , hydrocarbons produced: in order to decompose the _{(C m H n m ≧ 5} ) and dioxins, blowing may be carried out to the auxiliary fuel when insufficient combustion sustaining gas and heat.

According to the present invention, a series of steps of gasification melting, dehydration / pyrolysis, and gas reforming of waste are performed in one furnace without using expensive coke, and tar, dioxins, etc. Can be exhaust gas containing no. Dust containing low-boiling heavy metals can be separated into dust and energy gas by a bag filter or the like provided outside the furnace.

Next, in this gasification and melting furnace, a driving device for horizontally moving the side-blowing tuyere disposed inside the waste layer is provided, and a plurality of thermometers are provided on the outer periphery of the tuyere. , The reason for cooling each tuyere and upper blowing lance with cooling water, and the reason for providing a cooling device outside the refractory lining will be described below.

In the first zone, the combustion is performed by the combustion supporting gas blown from the primary tuyere, and the carbide is converted into a combustion gas to be a reducing gas mainly composed of high-temperature CO of 2000 ° C. or higher. The ash (inorganic oxide) and valuable metals contained in the carbide are melted by the sensible heat to form molten slag and molten metal.

Under a very severe atmosphere of 2000 ° C. or more,
The tuyere fittings and the surrounding refractory lining are in a worn environment. In order to avoid this wear, the primary tuyere fitting and the surrounding refractory lining are cooled with water, and the waste filled around is adhered to the refractory lining with a protective layer.
Alternatively, the most effective method is to cover the primary tuyere fitting and the refractory lining around it with a protective layer in which a molten material such as slag is solidified.

Even if molten slag and molten metal are present in the vicinity of the primary tuyere fittings and the surrounding refractory, if the primary tuyere fittings and the surrounding refractory are water-cooled, The melt can be cooled and solidified and adhered and solidified on the primary tuyere fitting and the refractory lining around it.

The simplest and most effective method for cooling the refractory lining is to cool it from the steel shell side.
As this cooling device, a well-known water cooling method such as a stave method, a jacket method or a shower watering method is an effective method, but forced air cooling may be used.

Further, if a driving device 20-1 for moving the tip of the primary tuyere in the horizontal direction is provided, the flame of the combustion by the supporting gas blown from the primary tuyere is supplied to the furnace. It becomes possible to shift to the center side. Since it is not preferable to raise the temperature of the tuyere tip to an unnecessarily high temperature and cause the combustion flame to reach the opposite side, it is necessary to determine an appropriate position of the primary tuyere by a driving device for moving in the horizontal direction. There is a need.

The structure of the tuyere is a multi-tube, and any structure may be used as long as it has a structure in which cooling water flows on the outermost side, supporting gas flows on the inner side, and auxiliary fuel flows on the innermost side. Not something.

The tuyere tip driving device 20-1 may be of a manual type, an electric type, etc., and any type may be employed, but a hydraulic type is preferred. The reason is that since a waste layer or the like is formed in the furnace, a hydraulic system having a propulsive force is effective to smoothly move the tuyere tip.

The above operation makes it possible to separate the refractory lining from the high temperature portion at the tip of the tuyere.
The protective layer can be formed by attaching waste to the lining refractory or solidifying a molten material such as slag. However, it is not preferable to increase the thickness of the protective layer more than necessary because the combustion zone of the waste is reduced, and it is only necessary to ensure the thickness of the protective layer that can protect the refractory. As a method for adjusting the thickness, a method is used in which two or more thermocouples are provided in the length direction of the outer peripheral portion of the primary tuyere and the temperature change is measured.

A method for measuring a temperature change is, for example, as follows. Thermocouple 31-1 provided on the lining refractory side
If the temperature measured by is 300-500 ° C,
If it can be determined that the protective layer is sufficiently formed on the lining refractory side and the temperature measured by the thermocouple 31-2 provided on the core side is 900 to 1100 ° C., the tuyere tip is melted or damaged. It can be determined that the combustion flame does not reach the facing side.

The same applies to the secondary tuyeres as to the primary tuyeres. The temperature around the secondary tuyere is in the range of 800 to 1400 ° C., and the tuyere fittings and the refractory lining around the tuyere are in an environment where they are worn away. In order to avoid this wear, the secondary tuyere fittings and the refractory lining around it are cooled with water, and the waste filled in the surroundings is covered with a protective layer that adheres to the refractory lining, or the slag is melted. The secondary tuyere fitting and the surrounding refractory lining can be covered with a solidified protective layer,
This is an effective method.

By employing the above-described apparatus and method according to the present invention, as shown in FIG. 1, the layer 25 having waste and / or slag adhered to the inner wall of the refractory lining and the primary and secondary tuyere fittings. It is formed.

Further, the area around the tertiary tuyere is 800 to 1400
C. Desirably in the range of 1000-1200.degree.
Although the ambient temperature is the same as that of the next tuyere, the tertiary tuyere fittings and the refractory lining around it are considered to be exposed to a severe atmosphere. For this reason, it is necessary to water-cool the tertiary tuyere fittings and the refractory lining therearound to maintain their soundness. However, there is hardly any solid matter mainly composed of waste around the tertiary tuyeres, and the space is formed by the generated gas, that is, a free board. Therefore, a driving device for moving the tertiary tuyeres in the horizontal direction is provided. No need.

The upper blowing lance is also the same as the tertiary tuyere, and it is necessary to cool the upper blowing lance hardware by water cooling to maintain its soundness. As described above, since it is necessary to supply to both the second zone and the third zone, the height of the lance must be changed appropriately, so that it is necessary to provide an elevating device that can move up and down. The combustion support gas blown from the upper blowing lance causes the combustion zone to be preferentially formed in the central part of the furnace, that is, the core, while forcing solid waste around it to dispose of solid waste. It is necessary to protect the refractory lining of the inner wall of the furnace from high-temperature gas by forming a layer mainly composed of a material, and to maintain its soundness. In order to perform this operation uniformly in the height direction of the furnace, it is preferable to change the height of the lance up and down as appropriate. A scattered waste and / or dust-adhered layer 26 is formed on the tertiary tuyere fitting and the lining refractory inner wall around the tertiary tuyere fitting, and the scattered waste and / or dust is also formed on the outer blowing lance fitting outer wall. Alternatively, a layer 27 to which dust adheres is formed, and these protective layers similarly protect the refractory lining and the tuyere fittings.

[0078]

EXAMPLES (Example 1 of the present invention) A gasification melting test of waste was conducted using a vertical furnace having the structure shown in FIG.
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: 0.6 m (furnace inner diameter after refractory lining) Furnace height: 2.4 m (however, height from furnace bottom to furnace top after refractory lining) Overhang inner diameter: 0 .25m (however, inside diameter after refractory lining) Overhang length: 0.4m (however, length after refractory lining) Height from furnace bottom to primary tuyere: 0.3m Secondary from furnace bottom Height from tuyere: 0.6m Height from furnace bottom to tertiary tuyere: 2.1m Upper lance outer diameter: 50mmφ Upper lance hole: One hole is installed at the center, and oxygen + nitrogen gas is blown 1 hole x 8mmφ x 0 degree (= vertical direction) Height from furnace bottom to lance tip: Standard 1.7m (Variable up and down) Position of thermocouple on refractory surface lined with waste layer: 1.0m ( (Refer to the height of the thermocouple from the bottom of the furnace) Position of the freeboard thermocouple: 1.4 m (from the bottom of the thermocouple to the bottom) Slag discharge diameter: 30mmφ Metal discharge diameter: 30mmφ Quantity Primary tuyere: 3 Secondary tuyere: 3 Tertiary tuyere: 3 Thermocouples at the outer periphery of the tip of the primary tuyere: each tuyere 2 each, ie, 6 total Thermocouples at the outer periphery of the tip of the secondary tuyere: 2 for each tuyere, ie, 6 total Upper lance: 1 Slag outlet: 1 Metal outlet: 1 Weirs: 1 arrangement Primary tuyere: equidistant every 120 degrees in the circumferential direction The primary tuyere tip protrudes 80 mm from the surface of the lining refractory inside the furnace as standard (however, it can be changed in the horizontal direction). Thermocouple: The position of 20mm from the tuyere tip toward the lining refractory surface and the position of 60mm Secondary tuyere: equidistant every 120 degrees in the circumferential direction The secondary tuyere tip is standard inside the furnace from the lining refractory surface Protrudes by 80 mm (but variable in the horizontal direction) Thermocouple: Refractory lining from tuyere tip 20mm position and 60mm position toward refractory surface Tertiary tuyere: equidistant every 120 degrees in the circumferential direction Top blowing lance: Furnace center Slag outlet: 150mm above furnace bottom end Metal outlet: Furnace bottom 10 mm above the edge Weir: 150 mm from the outer end of the overhang The waste used in the above test is three general types of municipal waste (samples 1, 2 and 3), each of which has a different degree of drying. 3408 kca per kg
1, 2518 kcal and 1628 kcal with a low heat generation reference.

Table 1 shows the composition of these wastes, Table 2 shows the composition of auxiliary materials used, and Table 3 shows the composition of auxiliary fuel used. The size of the waste was 10 to 100 mm.

[0081]

[Table 1]

[0082]

[Table 2]

[0083]

[Table 3]

Limestone used as an auxiliary material is 10 to 5
0mm lump, L used as auxiliary fuel
PG is propane: butane = 50: 50 (% by volume).

The supporting gas blown from the primary tuyere, secondary tuyere, tertiary tuyere and upper blowing lance is based on oxygen,
This is a gas in which nitrogen is slightly mixed. Table 4 shows the flow rates (the respective flow rates of oxygen and nitrogen). In the table, primary means primary tuyere. The same applies to the secondary, tertiary and upper blowing.

Table 4 shows the test conditions and Table 5 shows the results. In the table, the term "conditions" refers to the operating conditions in the steady state of this test, and was determined for each of samples 1, 2 and 3 according to the following procedures 1 to 8. In the test, first, sample 1 was charged into the furnace and treated under the conditions shown in the column of sample 1 in Table 4, and then changed to sample 2 and shown in the column of sample 2 as well. The treatment was performed under the following conditions.

[0087]

[Table 4]

[0088]

[Table 5]

(Procedure for Setting Processing Conditions) (1) The composition of the waste to be initially charged (here, sample 1) was analyzed in advance. The amount of C is necessary to determine the approximate value of the oxygen blowing amount, and the amount of the slag component is also necessary to determine the amount of limestone to be charged as the slag-making material. In this test, the amount of limestone was slag basicity = 1.
0 (where slag basicity = wt% CaO / wt% Si
O ₂ ).

(2) The gasification and melting furnace was heated in advance by a burner or the like, so that the waste was ignited even at room temperature without heating the supporting gas blown from the tuyere.

(3) The waste is charged into the furnace and has a height of 1.2
m. (4) Oxygen gas was gradually flowed from the primary tuyere.

(5) During the test, the top level of the waste layer was lowered due to the burning of the waste.
Raw materials (waste and limestone) were sequentially charged so as to maintain the range of 1.3 m. In the steady state, the waste feeding rate reached 75 kg / h and reached a steady state.

(6) The outlet for the molten slag was opened. (7) The temperature measured by the thermocouple on the refractory surface lined with the waste layer and the thermocouple in the freeboard space is always 80
The amount of oxygen gas blown from the primary tuyere, secondary tuyere, tertiary tuyere and upper blowing lance was adjusted so as to maintain 0 to 1400 ° C.

That is, the unloading speed is high, and the temperature of the refractory surface lining the waste layer and the free board is 14
When the temperature exceeded 00 ° C., the amount of oxygen gas from the primary tuyere was reduced. Conversely, the temperature of the refractory surface lining the waste layer is 80
When the temperature was lower than 0 ° C., oxygen gas was blown from the secondary tuyere and the upper blowing lance. When the temperature of the free board was lower than 800 ° C., oxygen gas was blown from the tertiary tuyere and the upper blowing lance.

(8) Measure the temperature of the molten slag from the discharge port (this measurement may be performed by a conventional method)
When the temperature was lower than a predetermined temperature (at least a temperature range in which the molten slag did not solidify, that is, 1300 to 1400 ° C.), LPG was blown from the primary tuyere.
In the case of Sample 3 corresponding thereto, if the calorific value of the waste itself was small, it was necessary to supply auxiliary fuel from the primary tuyere.

(9) Oxygen gas, nitrogen gas and LPG gas blown from the primary tuyere by a predetermined amount (the amount shown in Table 4)
, The primary tuyere was moved 8 mm further from the standard position, that is, a position protruding 80 mm from the surface of the refractory lining.

Here, the moving distance is set to 10% of the current value.
The standard position is the position where the thickness of the adhesion layer necessary for protection of the refractory lining the waste layer is determined in advance, and depends on the size such as the furnace diameter and the oxygen supply speed from the tuyere, that is, the waste treatment speed. It is a value that changes.

At this time, the operation was changed according to the cases shown in Table 6. Here, T1 is the lining refractory side temperature, and T2 is the core side temperature. Also, the cooling water amount was changed to an initial value of 2 m ³ / hr / line by 10%. Here, since T1 is located in the region of the adhesion layer, the temperature changes more sensitively with the position of the tuyere than with the change in the amount of cooling water. Therefore, the tuyere position was preferentially changed according to the value of T1 as shown below.
On the other hand, since T2 is located in the region of the combustion zone, the temperature changes more sensitively with the amount of cooling water than with the change in the tuyere position. Therefore, the cooling water amount was preferentially changed according to the value of T2 as shown below.

[0099]

[Table 6]

(10) Similarly, since the amount of oxygen gas and nitrogen gas blown from the secondary tuyere reached a predetermined amount (the amount shown in Table 4), the secondary tuyere was moved from the standard position, that is, the lining refractory surface. 8m more than 80mm protruding position
m inside the furnace. Here, the standard position is a position where the thickness of the adhesion layer necessary for protection of the refractory lining the waste layer is determined in advance, and is a value that changes depending on the size such as the furnace diameter and the waste processing speed.

The cooling water amount was changed to 10 m% at an initial value of 0.6 m ³ / hr / line. Hereinafter, the tuyere position and the amount of cooling water were changed in the same way as the primary tuyere.

(11) The metal outlet was opened when a predetermined amount of the molten metal was accumulated. When the metal was completely discharged, that is, when it was confirmed that slag was discharged from the metal discharge port, the metal discharge port was closed.

(12) By repeating the above (5) to (11), the optimum amount of the supporting gas, the amount of the auxiliary fuel to be blown (that is, the amount shown in the condition column of Table 4), The mouth position and the amount of cooling water could be derived. Here, nitrogen was blown as about 1/10 of oxygen,
When the oxygen concentration was ≧ 50%, it was possible to sufficiently cope with the problem. In addition, even when the sample was changed (from sample 1 to sample 2 and from sample 2 to sample 3), it was possible to appropriately cope with the case. In addition, in the steady state when the sample 2 was used, the charging rate of the waste was 94 kg / h and reached the steady state. In addition, in the steady state when the sample 3 was used, the charging rate of the waste material reached 128 kg / h and reached a steady state.

Table 5 shows the results obtained in the above tests.
Units are shown in units per ton of waste.

As shown in Table 5, a high-calorie energy gas mainly containing CO and H ₂ containing almost no dioxins (indicated as exhaust gas in the table), and a low boiling point gas such as mercury, cadmium, and lead. Dust enriched with heavy metals could be recovered.

The energy gas and the dust were discharged outside the furnace from the gas discharge port, and then separated and collected through a bag filter. The hydrocarbons in the exhaust gas, in particular, hydrocarbons, such as C _m H _n is a cause of pipe clogging (m ≧ 5) were at a concentration that completely negligible.

The molten metal mainly composed of valuable metals such as iron was discharged from the metal discharge port to the outside of the furnace, and the molten metal was discharged from the slag discharge port to the outside of the furnace.
The molten slag containing iO ₂ , CaO, and Al ₂ O ₃ as main components could be recovered.

The iron content (= T.Fe) in the molten slag, that is, the total iron content of the granular iron and the iron oxide is already 0.5% or less before the separation such as the magnetic separation, and is at the same level as the blast furnace slag. Therefore, the quality was evaluated as being sufficiently usable for roadbed materials and the like.

The separated metal was evaluated as having a quality usable as a counterweight or the like, since most of the molten metal was occupied by iron.

After conducting this test for one month in continuous operation for 24 hours, the furnace was cooled and the inside of the furnace was disassembled and inspected. As a result, on the operating surface of the refractory lining located in the waste layer of the furnace, waste and Solids mixed with slag are uniformly up to 50mm
It was covered with a moderate thickness. At this time, the amounts of cooling water at the primary and secondary tuyeres varied for each sample as shown in Table 5.

On the operating surface of the refractory lining located on the freeboard of the furnace, a solid material containing a mixture of waste and dust is uniformly covered with a thickness of up to about 40 mm. Not at all.

Further, the outer walls of the primary to tertiary side blowing tuyeres and the upper blowing lance are uniformly covered with a solid material containing waste and slag or dust with a thickness of at most about 30 mm. The tuyere and lance hardware were not worn at all.

(Comparative Example 1) A test was conducted using the same furnace as that of Example 1 of the present invention. However, the primary tuyere and the secondary tuyere were fixed, and the tuyere tip was located at the same position as the surface of the refractory lining. In addition, water cooling of the furnace skin and water cooling of the horizontal blowing tuyere and upper blowing lance were not performed.

As in Example 1 of the present invention, after performing this test for one month in continuous operation for 24 hours, the furnace was cooled and the inside of the furnace was dismantled. As a result, the operation of the refractory lining located in the waste layer of the furnace was performed. The surface was covered with a solid material containing a mixture of waste and slag with a maximum thickness of about 20 mm, but some thin deposits were also found. In particular, wear was observed around the primary tuyere and the secondary tuyere, and there was an erosion site of about 20 mm at the maximum.

[0115] On the operating surface of the refractory lining located on the free board of the furnace, a solid material containing a mixture of waste and dust was covered with a maximum thickness of about 20 mm, but thin adhesion was observed in some places. , Especially around the third tuyere
There was an erosion point of about 0 mm.

Further, the outer walls of the side-blowing tuyeres and the upper lances of the primary to tertiary tiers were thinly covered with a solid material containing waste and slag or dust. There was an erosion point of about 5 mm.

[0117]

According to the present invention, it is possible to economically dispose of the refractory lining and the tuyere tip, which are problems when gasifying and melting waste at a high temperature.

[Brief description of the drawings]

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

[Explanation of symbols]

1: Gasification and melting furnace 2: Refractory lining 3-1: Gas outlet 3-2: Gas discharge duct 4: Flow of energy gas and dust 5-1: Primary tuyere 5-2: Secondary tuyere 5 -3: tertiary tuyere 6-1: auxiliary fuel to be supplied to primary tuyere 6-2: auxiliary fuel to be supplied to secondary tuyere 6-3: auxiliary fuel to be supplied to tertiary tuyere 7-1: 7-2: Combustion gas supplied to the secondary tuyere 7-3: Combustion gas supplied to the tertiary tuyere 8: Molten slag 9: Molten metal 10 : Pusher 11-1: Waste inlet 11-2: Hopper 12: Waste 13: Overhang 14: Weir 15: Layer mainly composed of waste and carbide 16: Free board 17: Upper blowing lance 18: Upper blowing lance Supplementary gas to be supplied 19: Cooling water 20-1: Drive device 20-2: Lifting device 21: Waste Top level meter 22: Temperature converter 23: Thermocouple provided on the lining refractory surface 24: Thermocouple 25: Layer of waste and / or slag etc. attached to the lining refractory inner wall 26: Attachment to the lining refractory inner wall Waste and / or dust layer 27: Waste and / or dust adhering to the outer wall of the upper blowing lance 28: Slag outlet 29: Metal outlet 30: Cooling device 31-1: Outer perimeter of primary and secondary tuyeres Thermocouple on the refractory side of the lining 31-2: Thermocouple on the core side on the outer periphery of primary and secondary tuyere

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI F23G 5/50 F23G 5/50 ZABM (72) Inventor Kenjiro Shingo 4-5-33 Kitahama, Chuo-ku, Osaka-shi Sumitomo Metal Industries, Ltd. (72) Inventor Teruo Owada 4-5-33 Kitahama, Chuo-ku, Osaka-shi Inside Sumitomo Metal Industries, Ltd. (56) References JP-A-10-148317 (JP, A) JP-A-8-312939 (JP, A) JP-A-6-313532 (JP, A) JP-A-10-169942 (JP, A) JP-A-2-17985 (JP, A) JP-A-4-268006 (JP, A) JP-A-3 −249111 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F23G 5/24 F23G 5/44 F23G 5/50

Claims (3)

(57) [Claims] 1. A waste which burns waste to gasify organic matter in the waste and collects it as an energy gas, and collects ash and non-combustibles such as metals in the waste as molten slag and molten metal. A gasification and melting furnace,
It has a cooling device for cooling the refractory lined in the furnace from the steel shell on the back side, a waste loading inlet for charging the waste at the center in the height direction, and discharging generated gas at the top. It has a gas discharge port and a discharge port for molten slag and molten metal at the lower part, and injects auxiliary fuel between the gas discharge port and the waste loading port in the case of insufficient supporting gas and heat quantity 1 It has a side-blowing tuyere with a water-cooled structure at the stage, and an upper-blowing lance that can raise and lower a water-cooling structure that can inject auxiliary fuel when the amount of heat is insufficient in the upper part of the furnace. Between the discharge ports of the molten slag, there is a two-stage water-cooled side-blowing tuyere that blows auxiliary fuel when the amount of calcining gas or heat is insufficient. One stage moves the tip of the tuyere blowout horizontally between the lined refractory and the core. Gasification and melting furnace for wastes, characterized in that it comprises an that drive. 2. A waste product comprising at least two means for measuring the temperature of the outer periphery of the horizontally blown tuyere according to claim 1 in the longitudinal direction of the tuyere. Gasification and melting furnace. 3. Using the waste gasification and melting furnace according to claim 2 to determine a moving position of a tip of the horizontal blowing tuyere based on a temperature of an outer peripheral portion of the horizontal blowing tuyere. And a method for gasifying and melting the waste, wherein the amount of cooling water in the side-blowing tuyere is determined.