JP3460605B2 - Waste incineration and heat treatment furnace - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste incineration / heat treatment furnace in which a waste incinerator and an ash heat treatment furnace are directly connected to incinerate the waste and heat treat the ash generated at that time.

[0002]

2. Description of the Related Art (1) As a device for collectively performing the incineration of waste such as municipal waste and the ash treatment, (1) A slag tap type ash melting furnace is directly connected downstream of the combustion area of a grate incinerator to incinerate. A common flue for the furnace and the ash melting furnace (Japanese Patent Laid-Open No. 61-9
6128, hereinafter referred to as "Prior Art 1"), (2)
A burner-type surface melting furnace directly connected to the downstream of the combustion area of a grate incinerator (Japanese Patent No. 2681140, hereinafter,
(Referred to as "Prior Art 2"), (3) A rotary kiln type ash melting furnace having a dam is provided on the outlet side of the incinerator, and a heating burner is installed on the outlet side of the ash melting furnace. No. 5-312312, hereinafter referred to as “Prior Art 3”), (4) An incinerator ash melting furnace is directly connected to the downstream of the combustion region of the incinerator, and the exhaust gas in the incinerator is used as an oxidant, and Arranged so that ash melts using unburned materials as a heat source
(Japanese Patent Publication No. 6-3296, hereinafter referred to as “Prior Art 4”), (5) In (4), by blowing hot air from the hearth of the ash melting furnace, the combustion temperature in the furnace is increased to increase the ash. Which is designed to accelerate the melting of the powder (Japanese Patent Laid-Open No. 9-112854).
(Hereinafter referred to as "Prior Art 5"), (6) An incinerator ash melting furnace is directly connected downstream of the combustion region of the incinerator, and preheated air is blown from the ceiling of the ash melting furnace toward the ash layer to incinerate. Arranged so that the ash melts by using the unburned matter in the ash as a heat source (Japanese Patent No. 2681140, hereinafter, "Prior Art 6").
,), Etc. are proposed. That is, in these prior arts (1) to (6), the ash is melted after the waste is incinerated.

A schematic diagram (Prior Art 2) of a typical one is shown in FIG. In FIG. 8, 41 is a hopper, 42 is a grate, 43 is an ash hopper, 44 is a melting chamber, 45 is molten slag, 46 is a slag discharge chute, and 47 is an air preheater.

Municipal refuse thrown into the hopper 41 is sent to a grate 42 in the incinerator through a duster, and is ignited while moving on the grate 42 by air from below and radiant heat in the furnace. And burn. Then, the ash remaining after the combustion is sent to the melting chamber 44 via the ash hopper 43. In the melting chamber 44, the ash is melted by the combustion heat of the unburned materials in the melting burner or the ash and the radiant heat in the furnace to become the molten slag 45, which is discharged to the outside of the furnace via the slag discharge chute 45. To be done. Further, the exhaust gas generated in the ash melting furnace is returned to the incinerator via the air preheater 47. When the unburned material in the ash is used as the heat source, preheated air is supplied into the ash melting furnace. On the other hand, the combustion exhaust gas generated in the incinerator is discharged to the atmosphere via the waste heat boiler, the temperature reducing tower, the bag filter, the smoke exhaust facility, and the like.

All of the conventional waste incineration and ash treatment furnaces melt ash in the furnace, and do not heat the ash below the ash melting temperature. Further, no means is provided for averaging the spatial distribution of temperature in the ash treatment furnace and the time variation. Further, it is often the case that batch treatment is performed without distinguishing ash-treatment-unsuitable substances (relatively large lumps of metal, ceramics, etc.) and incineration-processable incineration ash.

An apparatus for heat treatment of dioxins in ash is disclosed in Japanese Patent Publication No. 6-38863 (Prior Art 7), but the heat treatment temperature is limited to the range of 200 to 550 ° C. Therefore, the temperature has not reached the temperature at which heavy metals (lead, arsenic, cadmium, mercury, etc.), which are harmful substances in ash, are volatilized.

Further, as the exhaust gas circulation equipment in the incinerator,
In addition to the one that conveys the exhaust gas by a circulation blower and blows it into the furnace, as described in Japanese Patent No. 2761417, the one that conveys the exhaust gas and blows it into the furnace by utilizing the ejector action of cold air is known. Has become.

[0008]

When the prior arts 1 to 6 are applied to the field of incineration and ash treatment of municipal waste, there are the following individual or common problems. (1) Dust and slag are easily partially solidified in a local low temperature region in the ash treatment furnace, and cleaning inside the furnace is indispensable (prior arts 1 to 6). (2) Stable ash treatment is difficult because the properties of incineration exhaust gas and incinerated ash vary (prior arts 1 to 6). (3) With respect to (1) and (2), there are large variations in the properties of slag, and it is difficult to effectively use slag (prior arts 2 to 6). (4) When priority is given to stable operation or low pollution on the incinerator side, the calorific value of the unburned gas in the furnace or unburned gas in the ash as the main heat source of the ash treatment furnace becomes low, and auxiliary fuel, hot air, etc. The new external heat source is required, the running cost becomes high, and the operation becomes complicated (prior arts 3 to 6). (5) Since a means for suppressing the scattering of ash from the ash treatment furnace outlet is not provided, a high slag rate cannot be achieved (prior arts 2 to 6). (6) Since most of the incineration exhaust gas is arranged so as to pass through the ash treatment furnace, it is difficult to make the temperature inside the ash treatment furnace uniform and to make the ash treatment furnace compact (Prior Art 3). (7) Due to the burner flame, a local high temperature part may be formed, and the inner wall and the like may be burned (prior arts 2 and 3). (8) A part of incinerated ash and dust is melted and solidified near the entrance of the ash processing furnace, and ash processing unsuitable material is easily caught in the bent part, etc., so hanging up easily occurs and stable operation for a long time is difficult (Prior art 2, 4-6). (9) Waste incineration consisting of waste incinerator and prior art 7
When an ash treatment furnace is used, as described above, the ash treatment temperature is low, and harmful heavy metals remain in the treated ash, which hinders effective use of the ash.

Further, in the conventional exhaust gas circulation system,
There are the following problems. In other words, in the exhaust gas circulation system that uses a circulation blower, the heat resistance of the components that make up the blower is limited,
Circulation of high temperature exhaust gas is difficult. For this reason, the improvement rate of the thermal efficiency due to the exhaust gas circulation remains at a small value. Since dust and the like in the exhaust gas adheres to the blades of the blower, it is necessary to regularly stop the equipment and clean it. The equipment cost of the blower is expensive. Running costs such as electricity costs for blowers and maintenance costs are high. When the exhaust gas is blown into the incinerator, the O ₂ concentration in the exhaust gas is too low and the stability of the flame in the furnace deteriorates. Since the blowing pressure of the exhaust gas into the furnace is regulated by the blower outlet pressure, it is difficult to increase the blowing pressure. There is such a problem.

In the method of circulating the exhaust gas by utilizing the ejector action of the cold air, the higher the temperature of the exhaust gas to be blown, the more remarkable the difference in viscosity between the cold air as the driving flow and the exhaust gas, and the lower the effect of the ejector. Become. The average temperature of the mixture of cold air and exhaust gas blown into the furnace decreases, and the stability of the flame in the furnace deteriorates. In this connection, the thermal efficiency is reduced. There is a problem.

The present invention has been made to solve such problems, and realizes long-term stable operation of an ash processing furnace without causing the above-mentioned problems, and has high performance. It is an object to realize energy saving and low pollution as a total system from incineration of wastes to ash treatment, while realizing realization and multi-functionalization.

[0012]

[Means for Solving the Problems] A first means for solving the above-mentioned problems is to incinerate waste by incinerating waste by directly connecting a waste incinerator and an ash heat treatment furnace . Melting
A waste incineration / heat treatment furnace that heat-treats below temperature ,
Part of the combustible gas generated in the waste incinerator and fuel
High-temperature air generated from a high-temperature air generator that burns and heats the air is used to swirl or tubular flames in an ash heat treatment furnace.
On the furnace wall in a direction perpendicular to the flow of exhaust gas and incinerator ash.
Blowing at high speed so that it is formed in the direction along
The inner wall of the ash heat treatment furnace due to the swirling flame or tubular flame
A waste incineration and heat treatment furnaces, characterized in that heating the (claim 1).

In this means, part of the combustible gas (combustion exhaust gas containing unburned components) generated in the waste incinerator and high temperature air are blown into the ash heat treatment furnace and A swirling or tubular flame of approximately symmetrical shape is formed.
Therefore, the inner wall of the furnace is heated almost uniformly by the radiation or direct heat transfer from these flames. Therefore, burnout trouble due to partial solidification of dust or slag or overheating of the inner wall is suppressed. Furthermore, due to the centrifugal effect of the swirling flow in the ash heat treatment furnace, a force outward in the radial direction acts on the incinerated ash and dust in the air flow and is pressed against the inner wall, so ash and dust can be prevented from scattering outside the furnace. .

[0014] direction to form a swirling flame or tubular flame ash heat treatment furnace, since the direction along the furnace wall of the heat treatment furnace in perpendicular direction of the flue gas and incinerated ash flow is preferred, the
In the method, the flame formation direction is limited to this direction.
It Particularly when the cross-sectional shape of the heat treatment furnace is close to a circle, it is desirable to blow in a tangential direction of the substantially circular shape at the blow point.

A second means for solving the above-mentioned problems is as follows.
In the first means, the high-temperature air generator heats air with a fuel, and high-temperature combustion exhaust gas of the fuel is blown into a secondary combustion region of the incinerator. Include
As a result, it can be used as a gas for stirring the inside of the incinerator (Claim 2).

In the present means, the high-temperature combustion exhaust gas discharged from the hot air generator, by blowing pivoting the secondary combustion zone of the waste incinerator, a furnace without changing the air excess ratio It can be stirred. Therefore,
With the complete combustion of the waste in the incinerator can be promoted, it is effective to lower NO _x of the exhaust gas.

A third means for solving the above-mentioned problems is as follows.
The waste incinerator and the ash heat treatment furnace are directly connected to incinerate the waste and heat the ash generated at that time below the melting temperature of the ash. a part of the generated combustible gas, and an oxidizing agent whose oxygen concentration has been adjusted, the turning flame or tubular flame ash heat treatment furnace, exhaust
Along the furnace wall, at a right angle to the flow of gas and incinerator ash
Blow at a high speed so that it is formed in the direction
The inner wall of the ash heat treatment furnace is heated by a swirling flame or a tubular flame.
Waste incineration and heat treatment furnaces, characterized in that that (claim 3)
Is.

Also in this means, similarly to the first means,
In the ash heat treatment furnace, a swirl flame or a tubular flame having a substantially symmetrical shape with respect to the furnace axis is formed, and radiation from these flames heats the inner wall of the furnace substantially uniformly. Therefore, a burning problem due to partial solidification of dust or slag or overheating of the inner wall is suppressed. Further, the centrifugal effect of the swirling flow in the ash heat treatment furnace presses the incinerated ash and dust in the air flow against the surface layer of the inner wall, so that ash scattering can be suppressed.

In addition, when the oxygen concentration in the oxidant is set to a high value, the absolute flow rate of the oxidant decreases, so that the residence time of the air flow in the ash melting furnace becomes long, and accordingly, the ash content is further increased. The scattering can be suppressed. Further, by setting the oxygen concentration in the oxidant to be low, low NO _x combustion can be realized in the ash heat treatment furnace.

A fourth means for solving the above problems is
The third means is characterized in that a mixed gas of a part of the exhaust gas generated in the waste incinerator and oxygen can be used as an oxidant (claim 4).

In this means, the sensible heat of the incineration exhaust gas and the unreacted oxygen can be effectively utilized, so that the combustion reaction in the ash heat treatment furnace is promoted and the temperature rise in the ash heat treatment furnace can be realized at a lower cost. Further, since the amount of nitrogen is smaller than that in the case of using air, the gas volume becomes small and the exhaust gas treatment system can be downsized.

The fifth means for solving the above-mentioned problems is as follows:
In any one of the first to fourth means, the temperature of the high temperature air or the oxidizer whose oxygen concentration is adjusted is adjusted so as to keep the temperature in the ash heat treatment furnace at a predetermined value. What is characterized is (Claim 5).

According to this means, even when the furnace conditions on the waste incinerator side change and the properties of the incinerator exhaust gas and incinerator ash change, the temperature of the high temperature air or the oxidizer whose oxygen concentration is adjusted is high. Since the temperature is adjusted and the temperature in the ash heat treatment furnace is constantly maintained within an appropriate range, stable operation for a long time can be realized. Also, as the oxygen concentration in the oxidant increases, the flame temperature increases,
As a result, the effect of increasing the temperature in the ash heat treatment furnace can be expected. As a result, even when the waste incinerator side is operated with priority on stabilization and low pollution, fluctuations in the properties of the slag generated in the ash heat treatment furnace can be suppressed to a small level.

A sixth means for solving the above-mentioned problems is as follows.
Any one of the first to fifth means, characterized in that it is provided with an auxiliary fuel supply device for adjusting the temperature in the ash heat treatment furnace (claim 6). is there.

According to the present means, the first means to the fifth means
Since the temperature inside the ash heat treatment furnace can be adjusted more directly than in the case of the above method, if the furnace condition on the incinerator side suddenly deteriorates, or if the gate becomes clogged for some reason, the incinerator side The temperature in the ash heat treatment furnace can be quickly readjusted without changing the operating conditions. Therefore, it is possible to maintain the operating rate of the plant at a high level.

Further, by supplying the fuel into the ash heat treatment furnace, the temperature inside the ash heat treatment furnace can be adjusted independently of the incinerator side, so that the work time for starting and stopping the plant can be shortened. .

The seventh means for solving the above-mentioned problems is as follows.
The sixth means, wherein the auxiliary fuel is a carbon-containing fuel, and means for stirring the fuel and ash is provided in the ash treatment furnace (claim 7). ).

In this means, a carbon-containing fuel is used as an auxiliary fuel, and a means for stirring the fuel and ash is provided in the ash treatment furnace, so that the ash is heat-treated in a reducing atmosphere. be able to. As a result, the decomposition rate of dioxins in ash can be increased. If the carbon-containing fuel has a small particle size like fine coke and has good concomitant properties with the air flow in the furnace, it is pressed against the inner wall by the centrifugal effect of the swirling flow in the furnace, It goes without saying that a certain degree of fuel dispersibility can be ensured even without means for stirring.

The eighth means for solving the above-mentioned problems is as follows.
Any one of the first to seventh means is characterized in that the downstream side of the ash heat treatment furnace is gradually tapered toward the outlet (claim 8).

In this means, since the shape of the ash heat treatment furnace is gradually narrowed toward the outlet, the swirling flow velocity of the air flow is increased toward the downstream side. Therefore, the efficiency of collecting ash and dust is improved, the inner wall can be more effectively heated by the flame, and the slag is concentrated in one place under the influence of gravity, and the spout is less likely to be blocked. In addition, since the mixing of the gas in the furnace is promoted, the pollution of exhaust gas can be reduced, which is an added benefit.

The ninth means for solving the above-mentioned problems is as follows:
Any of the first to eighth means, wherein a hazardous waste supply device is arranged so that gaseous, liquid, or particulate hazardous waste is blown into the ash heat treatment furnace or upstream thereof. And an exhaust gas treatment device is disposed downstream of the ash heat treatment furnace (claim 9).

In this means, since harmful substances such as fly ash and waste oil can be treated in the ash heat treatment furnace in parallel with the treatment of incinerated ash, energy saving and multifunctionalization as a waste treatment device can be realized. .

A tenth means for solving the above-mentioned problems is any one of the first means to the ninth means, and detects an unsuitable material for heat treatment in incineration ash on the upstream side of the ash heat treatment furnace. The waste incineration / heat treatment furnace (Claim 10) is characterized in that an unsuitable substance removing device for removing the waste is disposed.

In the present means, unsuitable substances for heat treatment are detected and removed in the upstream of the ash heat treatment furnace, so that there is no hanging of incinerated ash near the inlet of the ash heat treatment furnace or clogging of the outlet.
Stable heat treatment for a long time can be realized. Also, if non-heat unsuitable material to ash heat treatment furnace is interposed, it is possible to set the average temperature in the furnace to be lower, the low NO _x reduction of energy saving and exhaust gas can be achieved.

An eleventh means for solving the above-mentioned problems is any of the first to tenth means, wherein the ash heat treatment furnace is a rotary kiln type ash heat treatment furnace. This is a waste incineration / heat treatment furnace (claim 11).

In this means, since the ash heat treatment furnace is inclined downward toward the downstream side and is rotated, even if there is an unsuitable heat treatment object, the ash heat treatment does not cause the ash to remain in the furnace, and the incinerated ash is not retained. It can be forcibly transported to the downstream side. Also, dust attached to the inner wall of the ash heat treatment furnace,
When the size of the ash heat treatment furnace reaches a certain level, the ash heat treatment furnace does not need to be cleaned because it is detached by its own weight and is transported to the downstream side. Therefore, labor saving can be realized and the operation rate of the apparatus can be increased.

A twelfth means for solving the above problems is to directly incinerate the waste by directly connecting the waste incinerator and the ash heat treatment furnace, and heat the ash generated at that time at a temperature not higher than the melting temperature of the ash. <br /> A waste incineration / heat treatment furnace to be treated, in which a damper for suppressing inflow of incineration exhaust gas from the waste incinerator to the ash heat treatment furnace is provided in a communication part between the waste incinerator and the ash heat treatment furnace. Is installed and the pressure inside the ash heat treatment furnace is equal to that inside the waste incinerator.
Adjust the damper opening so that it is slightly higher than the pressure.
Waste incineration and heat treatment furnaces, characterized in that there (claim 1
2).

In this means, the pressure in the furnace of the ash heat treatment furnace is
Is set to be slightly higher than the internal pressure of the waste incinerator.
Since damper opening is adjusted, Ru can suppress the low temperature incineration exhaust gas entering the ash heat treatment furnace. Therefore, the inside of the ash heat treatment furnace is maintained at a high temperature, stable heat treatment can be realized, and the absolute amount of gas to be heated is reduced, so that energy saving can be realized. Moreover, since chlorine, which is one of the constituent elements of dioxins, can be prevented from entering the ash heat treatment furnace together with the incinerator exhaust gas, the generation of dioxins downstream from the ash heat treatment furnace can be suppressed to a low level.

The damper opening is adjusted as follows. That is, the internal pressures of the waste incinerator and the ash heat treatment furnace are detected, and the damper opening is adjusted so that the internal pressure of the ash heat treatment furnace is slightly higher than the internal pressure of the waste incinerator.
It

A thirteenth means for solving the above-mentioned problems is any one of the first to twelfth means, and conveys exhaust gas from a waste incinerator by using hot air as a driving flow. An ejector device for injecting air into the waste incinerator is provided (claim 1
3).

According to the present means, the exhaust gas of the waste incinerator (in many cases, the secondary combustion exhaust gas at the outlet of the exhaust heat boiler) is conveyed by the ejector device using high temperature air as a driving flow, and the waste incinerator is exhausted. Since it is being blown into the air, it uses the high viscosity and kinetic energy of hot air,
Exhaust gas can be blown into the furnace at high speed. Further, by the action of this jet flow, it becomes possible to directly control the flame in the furnace. Furthermore, since the temperature of the mixture of high temperature air and exhaust gas is high, the mixture becomes highly viscous, and stirring in the furnace can be performed more effectively. Also, the required power for exhaust gas circulation is less than that of blowers,
Energy saving can be realized. Further, since the high temperature dust-containing gas can be stably conveyed, the high temperature exhaust gas can be recirculated, and the thermal efficiency is improved, which leads to energy saving.
The ejector may be provided in the exhaust gas circulation passage or may be provided at the blowing port into the furnace. However, in the former case, a flame is formed immediately downstream of the ejector, so it is necessary to carry out refractory construction downstream of the ejector.

A fourteenth means for solving the above-mentioned problems is any one of the first to thirteenth means, and the combustibility generated in the waste incinerator is generated by using hot air as a driving flow. An ejector device for carrying gas and blowing the gas into the ash heat treatment furnace is provided (Claim 14).

Also in the present means, the exhaust gas in the waste incinerator (primary combustion exhaust gas generated in the waste incinerator) is conveyed by the ejector device using high temperature air as a driving flow, and is introduced into the ash heat treatment furnace. Since the blowing is performed, it is possible to blow the exhaust gas into the furnace at high speed by utilizing the high viscous kinetic energy of high temperature air. Further, by the action of this jet flow, it becomes possible to directly control the flame in the furnace. Therefore, the flame in the furnace becomes stable, which leads to low pollution and improvement in operating rate. Furthermore, since the temperature of the mixture of high temperature air and exhaust gas is high, the mixture becomes highly viscous, and stirring in the furnace can be performed more effectively. Therefore, low air ratio combustion is possible, the amount of exhaust gas is reduced, and energy is saved. Further, the required power for exhaust gas circulation is smaller than that of a blower or the like, so that energy saving can be realized. Further, since the high temperature dust-containing gas can be stably conveyed, the high temperature exhaust gas can be recirculated, and the thermal efficiency is improved, which leads to energy saving. The ejector is
It may be provided in the exhaust gas circulation passage or may be provided in the blowing port into the furnace. However, in the former case, a flame is formed immediately downstream of the ejector, so it is necessary to carry out refractory construction downstream of the ejector.

A fifteenth means for solving the above problem is to use the exhaust gas downstream of the induction fan installed in the exhaust gas diffusion system, instead of the hot air in the thirteenth means or the fourteenth means. Incineration of waste characterized by
It is a heat treatment furnace (claim 15).

In this means, since the exhaust gas downstream of the induction fan installed in the exhaust gas discharge system is used as the drive flow of the ejector device, a dedicated blower for circulating the exhaust gas is not required, and the exhaust gas treatment facility is not required. The sensible heat of the low-temperature exhaust gas that has passed through can be recovered. Also,
Since the O ₂ in the low temperature exhaust gas can be used as the O ₂ for combustion in the incinerator, the amount of supplied air can be reduced.

A sixteenth means for solving the above-mentioned problems is to incinerate the waste by directly connecting the waste incinerator and the ash heat treatment furnace, and heat the ash generated at that time at a temperature not higher than the melting temperature of the ash. A waste incineration / heat treatment furnace, wherein the waste incinerator is an exhaust gas circulation type incinerator, and the exhaust gas of the ash heat treatment furnace is sucked by an exhaust gas circulation blower of the waste incinerator, and with it, A waste incineration / heat treatment furnace characterized in that unburned gas in an upstream region of the waste incinerator is drawn into the ash heat treatment furnace via a bypass.
(Claim 16)

The exhaust gas circulation type incinerator is an incinerator in which a part of the exhaust gas discharged from the incinerator is blown into the incinerator again and used for combustion. In this means, the exhaust gas circulating blower for the incinerator is used to suck the exhaust gas from the ash heat treatment furnace so that the unburned gas in the upstream region of the incinerator is drawn into the ash heat treatment furnace via the bypass . Yo
Therefore, it is not necessary to install a special blower for blowing the combustion exhaust gas into the ash heat treatment furnace, and energy saving can be realized. Also, since the exhaust gas from the ash heat treatment furnace is returned to the inside of the incinerator via the circulation blower of the incinerator, the thermal efficiency is improved and the ash heat treatment furnace does not need to be equipped with an exhaust gas treatment device by itself, reducing equipment costs. It also becomes. Further, when combined with the twelfth means, the damper can prevent the incinerator exhaust gas from excessively entering from the inlet of the ash heat treatment furnace.

A seventeenth means for solving the above-mentioned problems is any one of the first to eleventh means, wherein the waste incinerator is provided in a primary combustion chamber (main combustion chamber). a twice-flow grate incinerator with an intermediate ceiling, wherein the Allowed
Of the gas stream in which the combustion gas is separated by the intermediate ceiling,
A part of the exhaust gas from the side that contains a lot of unburned gas
Is those characterized by (claim 17) that.

In the present means, the intermediate ceiling in the incinerator clearly separates the exhaust gas containing a large amount of unburned gas and the exhaust gas containing a large amount of unreacted oxygen, and their compositions are relatively stable. By applying the former unburned gas as the main heat source (combustible gas) of the ash heat treatment furnace, it is possible to more effectively realize long-term stable operation and energy saving of the ash heat treatment furnace.

An eighteenth means for solving the above-mentioned problems is any one of the first to seventeenth means, wherein the temperature in the ash heat treatment furnace is 800 ° C. or higher and the melting temperature of ash is A temperature control device for controlling the following is provided (claim 18).

According to this means, it is possible to decompose dioxins by maintaining a temperature of 800 ° C. or higher,
Moreover, by controlling the temperature to be lower than the melting temperature of ash, troubles due to welding and solidification of ash and dust can be avoided.

A nineteenth means for solving the above-mentioned problems is any one of the first to eighteenth means, and the fuel and the oxidizer are added so that the inside of the ash heat treatment furnace is in a reducing atmosphere. A device for adjusting at least one of the above is provided (Claim 19).

In this means, by maintaining the reducing atmosphere in the ash heat treatment furnace, the volatilization of heavy metals in the ash can be promoted and the decomposition efficiency of dioxins can be increased. Further, since the reducing atmosphere is present in the vicinity of the inner wall of the ash heat treatment furnace, the inner wall can be prevented from burning. In addition,
The fuel or oxidant to be adjusted may be put into the waste incinerator or the ash heat treatment furnace.

[0054]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
It is a figure which shows an example. In FIG. 1, 1 is a hopper, 2 is garbage, 3 is a main combustion chamber, 4 is incineration ash, 5 is a tapered flue, 6 is a heat treatment inappropriate substance detection / removal section, 7 is a lattice, 8 is an ash heat treatment furnace,
9 is a slag, 10 is a slag conveyor, 11 is a slag reservoir, 12 is an adjustment damper, 13 is a dust remover, 14 is a heat exchanger, 15 is an exhaust gas circulation blower, 16 is an intermediate ceiling, 18 is an exhaust heat boiler, and 19 is a furnace. An inner stirring gas outlet and a gas outlet 20 are provided.

The dust 2 charged in the hopper 1 is ignited and burned in the main combustion chamber 3 by hot air from below the grate or by an auxiliary burner (not shown) installed in the main combustion chamber 3. The incineration ash 4 generated by the combustion passes through the tapered flue 5 and enters the heat treatment inappropriate substance detection / removal unit 6. As will be described later, the heat treatment inappropriate substance detection / removal unit 6 is provided with a detector for heat treatment inappropriate substance and a device for discharging the detected heat treatment inappropriate substance to the outside of the furnace. Incinerated ash from which heat treatment inappropriate substances have been removed 4
Falls through the lattice 7, is heat-treated in the ash heat treatment furnace 8 into slag 9, and is dropped onto the slag conveyor 10,
It is stored in the slag reservoir 11. It is also possible to drop the slag into water without using the slag conveyor 10 and the slag reservoir 11 to form granulated slag.

An adjustment damper 12 for suppressing the amount of exhaust gas entering the ash heat treatment furnace 8 from the waste incinerator is provided between the heat treatment unsuitable substance detection / removal section 6 and the ash heat treatment furnace 8. Combustion exhaust gas is prevented from flowing in. In addition,
Instead of providing the adjustment damper 12, the ash heat treatment furnace 8 may be operated so as to always fill the incinerated ash 4 upstream to form a material seal.

As will be described later, a gas blowout port 20 is provided in the ash heat treatment furnace 8, and as shown in the sectional view AA ′, the gas blowout port 20 is used in the waste incinerator. The mixed gas of the combustible gas (unburned gas in the incinerator) and high-temperature air generated in 2) is blown into the furnace at high speed.
The blowing direction of this high-temperature mixed gas is tangential to the inner wall of the ash heat treatment furnace 8 as seen in the AA ′ cross-sectional view, so that it is shown in the ash heat treatment furnace 8 by the blown high-temperature mixed gas. A swirling or tubular flame is produced as described above.

Therefore, the inner wall of the furnace is heated almost uniformly by the radiation or direct heat transfer from these flames. Therefore,
Burnout trouble due to partial solidification of dust or slag or overheating of the inner wall is suppressed. Further, due to the centrifugal effect of the swirling flow in the ash heat treatment furnace, incineration ash and dust in the air flow are collected on the inner wall surface layer portion, so that scattering of dust downstream from the ash heat treatment furnace is suppressed.

Exhaust gas generated by burning unburned gas in the incinerator in the ash heat treatment furnace 8 is introduced into the exhaust gas circulation system of the waste incinerator, dust is removed by the dust remover 13, and cooled by the heat exchanger 14. Then, through the exhaust gas circulation blower 15,
It is mixed with oxygen and blown again into the waste incinerator.
Instead of such a system, an independent blower may be installed and the exhaust gas that has passed through the ash heat treatment furnace 8 may be pressurized and used as a stirring gas in the secondary combustion chamber 17, which will be described later.

An intermediate ceiling 16 is provided in the main combustion chamber 3, whereby the flow of exhaust gas is divided into two as shown by the arrows in the figure. The exhaust gas passing through the upper portion of the intermediate ceiling 16 contains a large amount of unburned gas, and the exhaust gas passing through the lower portion of the intermediate ceiling 16 contains a large amount of unreacted oxygen, and their composition is relatively stable.

In the present embodiment, this intermediate ceiling 1
Exhaust gas passing through the upper part of 6, that is, a part of the exhaust gas containing a large amount of unburned gas is taken out and blown into the ash heat treatment furnace 8 as unburned gas in the incinerator, and is used as a main heat source of the ash heat treatment furnace 8. That is, a part of the exhaust gas passing through the upper part of the intermediate ceiling 16 is drawn into the ash heat treatment furnace 8 through the gas outlet 20 by the negative pressure generated by the exhaust gas circulation blower 15. Therefore, a special blower for blowing the unburned gas in the incinerator into the ash heat treatment furnace 8 is not necessary.

On the other hand, since the exhaust gas passing through the lower portion of the intermediate ceiling 16 contains only a small amount of unburned matter, it cannot be used as a fuel even if it is put into the ash heat treatment furnace 8, but rather the ash heat treatment furnace 8 It is not preferable because the internal temperature is lowered and the dioxins contained in the exhaust gas and chlorine as a starting material thereof enter the ash heat treatment furnace. The aforementioned adjustment damper 12 is provided to prevent this exhaust gas from flowing into the ash heat treatment furnace 8. Specifically, the pressure inside the furnace near the boundary between the main combustion chamber 3 and the tapered flue 5 and the pressure inside the ash heat treatment furnace 8 are detected, and the damper 12 is kept so that the latter pressure is kept slightly higher than the former pressure. Adjust the opening of.

Depending on the design conditions of the furnace, the pressure of the latter may be lower than the pressure of the former (for example, in the embodiment shown in FIG. 1, the exhaust gas circulating blower 15 is used in the incinerator). Since the unburned gas is drawn into the ash heat treatment furnace 8, the pressure of the latter becomes lower than the pressure of the former.) Even in this case, the pressure difference between the two is kept small, and the exhaust gas is as narrow as possible. The opening is adjusted so that it does not flow into the ash heat treatment furnace.

Most of the exhaust gas bypassing the intermediate ceiling 16 is guided to the secondary combustion chamber 17, where it is agitated by the agitating gas blown from the outlet 19 of the agitating gas in the furnace to form a swirling flow, and the secondary Burn efficiently. After exchanging heat with the exhaust heat boiler 18, most of the heat is exchanged with the dust remover 1.
3, introduced into an exhaust gas circulation system including a heat exchanger 14 and an exhaust gas circulation blower 15, mixed with oxygen, and blown again into the waste incinerator. Part of the exhaust gas is sent to the exhaust gas treatment device, and after dust and harmful substances are removed, it is released from the chimney into the atmosphere.

In the embodiment shown in FIG. 1, the gas obtained by mixing the exhaust gas passing through the exhaust gas circulation blower 15 with oxygen is blown into the main combustion chamber 3 from the lower part of the grate. Etc., the grate may be corroded. In such a case, it is preferable to blow air from under the grate and blow the mixed gas of oxygen and exhaust gas directly into the main combustion chamber.

The high temperature air blown into the ash heat treatment furnace 8 is produced by heating the air with a high temperature air generator (not shown). Generally, the fuel is burned and the heat heats the air. When the combustion exhaust gas at this time is used as the stirring gas blown from the outlet 19 for the stirring gas in the furnace, the inside of the furnace can be stirred without changing the excess air ratio, and the combustion in the furnace is promoted. It is also effective for reducing NO _x in exhaust gas. Further, the sensible heat of the combustion exhaust gas of the high temperature air generator can be recovered by the exhaust heat boiler 18.

In this embodiment, the ash heat treatment furnace 8 is also used.
In the above, a mixed gas of a gas in the incinerator and high temperature air is blown in, but an oxidizer whose oxygen concentration is adjusted may be used instead of the high temperature air. The oxidant can be produced, for example, by mixing oxygen and exhaust gas from a waste incinerator. In this method, when the oxygen concentration in the oxidant is set to be high, the absolute flow rate of the oxidant decreases, so that the residence time of the air flow in the ash heat treatment furnace becomes longer, and as a result, ash and dust are further increased. The collection efficiency of can be improved. Further, by setting the oxygen concentration in the oxidant to be low, low NO _x combustion can be realized in the ash heat treatment furnace.

Further, by detecting the temperature in the ash heat treatment furnace 8,
In order to keep this temperature constant, it is preferable to adjust the temperature of the hot air or the oxidizer whose oxygen concentration is adjusted.
As a result, long-term stable operation can be realized even when the furnace conditions on the waste incinerator side change and the properties of the incinerator exhaust gas and incinerator ash change. Therefore, even when the waste incinerator side is operated with priority on stabilization and low pollution, the fluctuation of the properties of the slag generated in the ash heat treatment furnace 8 can be suppressed to a small level.

Another means may be used to adjust the temperature in the ash heat treatment furnace 8. At this time, the temperature in the ash heat treatment furnace 8 is preferably controlled to 800 ° C. or higher. This enables simultaneous reduction of dioxins and heavy metals in ash. Therefore, the ash after the heat treatment can be effectively used. Furthermore, since the melting point of the main heavy metals exceeds the melting point in the furnace, it is possible to suppress the solidification of these in the furnace. Furthermore, the temperature in the ash heat treatment furnace 8 is preferably controlled to be equal to or lower than the melting temperature of ash. Heavy metal types, melting points, boiling points (or sublimation points) that are particularly problematic in the ash processing field
Is as follows.

[0070]

[Table 1]

Of these, the amount of pure lead produced by the ash treatment is small, and it is often produced as a compound such as lead chloride. Therefore, as is clear from Table 1, in order to volatilize the main heavy metals in the ash, even if the temperature distribution in the furnace is taken into consideration, heating within a range not exceeding the melting temperature of the ash (1100 to 1400 ° C) Is enough. Therefore, although the maximum heating temperature depends on the type of ash, heating at 1000 ° C. or lower is preferable because the heavy metal in the ash can be volatilized without surely melting the ash.

Actually, incinerator ash was filled in a tubular furnace,
As a result of heating the furnace to 1000 ℃ as a reducing atmosphere, the lead contained in 1000 to 2000 mg / kg before the heat treatment was reduced to 600 mg / kg or less, which was below the soil environmental standard value.

The temperature in the ash heat treatment furnace 8 may be adjusted by blowing an auxiliary fuel into the ash heat treatment furnace 8 by providing an auxiliary fuel supply device and adjusting the amount of the auxiliary fuel. As a result, the temperature in the ash heat treatment furnace 8 can be controlled accurately, so that when the furnace condition on the incinerator side suddenly deteriorates, or when the outlet of the ash heat treatment furnace 8 becomes clogged for some reason. In addition, the temperature in the ash heat treatment furnace can be quickly readjusted without changing the operating conditions on the incinerator side. Therefore, it is possible to maintain the operating rate of the plant at a high level. In addition, since the temperature inside the ash heat treatment furnace can be adjusted independently of the incinerator side, it is possible to shorten the work time for starting and shutting down the plant.

As the auxiliary fuel to be blown, it is preferable to use a fuel containing carbon, for example, in the form of powder. In this way, the blown carbon-containing fuel is pressed against the vicinity of the inner wall by centrifugal force as in the case of the ash, and the carbon-containing fuel is burned at this location, so that the vicinity of the ash selectively becomes a reducing atmosphere. This further promotes the volatilization of heavy metals from the ash. Further, since the reducing atmosphere is also present in the vicinity of the inner wall, burnout of the inner wall is suppressed. As a result, the operation rate of the device is increased, and the repair cost for refilling the furnace material is reduced.

FIG. 2 shows a system of exhaust gas, steam, etc. in the waste incineration heat treatment furnace which is an example of the embodiment of the present invention. The oxygen separated from the air by the oxygen production device is mixed with the exhaust gas of the exhaust gas circulation system in the mixer, and is blown into the incinerator to burn the refuse. Most of the exhaust gas from the incinerator flows into an exhaust gas circulation system consisting of a dust remover, a heat exchanger, and a blower, is mixed with oxygen by a mixer, and is blown into the incinerator again. In this case, air is blown from below the grate, and the exhaust gas mixed with oxygen in the mixer is blown directly into the combustion chamber. By changing the ratio of mixed exhaust gas and oxygen, it is possible to control the combustion state of dust in the incinerator, and unlike the case of blowing air,
Since excess nitrogen is not blown into the furnace, the exhaust gas volume can be reduced and the exhaust gas treatment equipment can be downsized.

Of the exhaust gas that does not flow to the exhaust gas circulation system,
One part flows into the ash heat treatment furnace 8 as described above, and the other part flows into the exhaust gas treatment facility. The exhaust gas that is burned in the ash heat treatment furnace to heat the incinerated ash is guided to the dust remover as described above, and enters the exhaust gas circulation system. Exhaust gas that has flowed into the exhaust gas treatment equipment has its moisture removed and is emitted from the chimney to the atmosphere. When the CO ₂ fixing device is provided, CO _{2 in} the exhaust gas is not fixed and is not released to the atmosphere. Moisture removed by the exhaust gas treatment facility is discharged after being treated by the wastewater treatment facility.

Most of the exhaust gas sensible heat of the incinerator is used to generate steam in the exhaust gas boiler, and the generated steam is
Used in power plants. In FIG. 2, the heat exchanger is used to heat the feedwater to the waste heat boiler.

FIG. 3 shows details of an example of the ash heat treatment furnace in one example of the embodiment of the present invention. In the following figures, the same components as those shown in the previous figures in the section of the embodiment of the invention are designated by the same reference numerals and the description thereof will be omitted. In FIG. 3, 21 is a gas blowing port in the incinerator, 22 is a high temperature air blowing port, and 23 is an outlet.

The ash heat treatment furnace 8 is a furnace having a substantially circular cross section, and the downstream side of the ash heat treatment furnace 8 is gradually tapered toward the outlet 23. A gas outlet 20 is provided in a part of the upstream side wall, and this is connected to the gas inlet 21 and the high temperature air inlet 22 in the incinerator. Exhaust gas blown from the gas blow-in port 21 inside the incinerator furnace and high-temperature air blown from the high-temperature air blow-in port 22 are mixed at the gas blow-out port 20 and are tangential to the cross section of the ash heat treatment furnace 8 having a substantially circular cross section. It is blown toward, that is, along the circumference. As a result, a swirling flame or tubular flame having a substantially symmetrical shape with respect to the furnace axis is formed.

Therefore, the inner wall of the furnace is heated almost uniformly by the radiation or direct heat transfer from these flames. Therefore,
Burnout trouble due to partial solidification of dust or slag or overheating of the inner wall is suppressed. Furthermore, since the incinerated ash and dust in the air stream are collected at the surface layer of the inner wall due to the centrifugal effect of the swirling flow in the ash heat treatment furnace, a high slag rate can be achieved.
Further, since the waste incinerator and the ash heat treatment furnace 8 are directly connected to each other, the high temperature ash is introduced into the ash heat treatment furnace 8 without being cooled, so that the thermal efficiency is increased.

Further, since the downstream side of the ash heat treatment furnace 8 becomes thinner as it approaches the outlet 23, the swirling flow velocity of the flame becomes higher toward the downstream side. Therefore, the efficiency of collecting ash and dust is improved. Moreover, the inner wall can be more effectively heated by the flame. Further, for example, when the ash is melted, the slag is concentrated in one place and the hot water is discharged, so that the sprue is unlikely to be blocked. In addition, since the mixing of the gas in the furnace is promoted, the pollution of exhaust gas can be reduced.

FIG. 4 is a diagram showing details of the connecting portion between the tapered flue, the heat treatment inappropriate substance detection / removal portion and the ash heat treatment furnace in one example of the embodiment of the present invention. In FIG. 4, 24 is a high temperature air generator, and 25 is a harmful substance supply device. P
Powdery toxic substances such as CB are charged from the toxic substance supply device 25 into the heat treatment inappropriate substance detection / removal unit 6, and gas / liquid toxic substances such as fly ash and waste oil are blown into the incinerator with unburned gas. Mouth 2
1 is blown into the heat treatment furnace 8 together with the unburned gas in the incinerator. These substances are decomposed in the high temperature ash heat treatment furnace 8 and finally absorbed by the exhaust gas treatment apparatus shown in FIG.

The harmful substances in powder form are not blown in from the unburned gas blowing port 21 in the incinerator, but the substance not suitable for heat treatment detection / removal section 6 is charged with these substances.
This is to prevent this from being blown from 2 and scattered in the ash heat treatment furnace 8 without being sufficiently decomposed and discharged from the outlet of the ash heat treatment furnace 8 in an untreated state.
Therefore, it is charged into the heat treatment inappropriate substance detection / removal section 6 and put into the ash heat treatment furnace 8 together with the incinerated ash 4 to promote decomposition.

An adjustment damper 12 is provided at the boundary between the heat treatment inadequate substance detection / removal section 6 and the ash heat treatment furnace 8, and the damper is moved up and down by a hydraulic cylinder to move the ash from the waste incinerator as described above. The amount of exhaust gas flowing into the heat treatment furnace 8 is suppressed. In actual operation, the damper opening is 4
The opening is almost the same as the surface of the.

FIG. 5 is a diagram showing details of the heat treatment inappropriate substance detection / removal unit in one example of the embodiment of the present invention. In FIG. 5, 26 is a TV camera, 27 is a pusher, and 28 is a pusher.
Is a cooling air inlet, 29 is a shielding plate, 30 is a cover, 31
Is a vibrating device.

The unsuitable material for heat treatment is an incombustible material composed of a large lump of steel or the like and does not contain harmful substances such as dioxins. If such a material enters the ash heat treatment furnace, the equipment may be damaged or the inlet may be damaged. There is a risk of incineration ash hanging up in the vicinity or blocking the sprue. Therefore,
A lattice 7 is provided on the outlet side of the heat treatment inappropriate substance detection / removal unit 6 so that these heat treatment inappropriate substances do not fall into the ash heat treatment furnace while being hindered by the lattice. The lattice 7 is hollow and is cooled by the air supplied from the cooling air inlet 27.

The unsuitable heat treatment material remaining on the lattice 7 is monitored by the TV camera 26, and the pusher 27 is operated to discharge it to the outside of the furnace. At this time, the shielding plate 29 is raised to make a space through which the heat-treatable material passes. The cover 30 is hung from the upper structure by a hinge, and is pushed and rotated by an unsuitable material for heat treatment, whereby the unsuitable material for heat treatment passes through the cover 30 and is discharged to the outside of the furnace. After that, the pusher 27 is returned to the original position, and the shield plate 29 is lowered to seal the inside of the furnace. The grating 7 is provided with a vibrating device 31,
Is giving vibration to. As a result, the incinerated ash on the grid 7 falls without remaining on the grid 7 and is guided into the ash heat treatment furnace.

FIG. 6 is a diagram showing an example of an embodiment of the present invention in which the ash heat treatment furnace is a rotary kiln type. In FIG. 6, 8'is a rotary kiln that is an ash heat treatment furnace, 32 is a roller, and 33 is an inlet for a mixed gas of combustible gas and high temperature air. The rotation of the roller 32 rotates the rotary kiln 8 '. The rotary kiln 8'is
It is inclined downward toward the downstream side, and the downstream side is tapered.

The combustible gas and the high temperature air are blown into the blowing port 33.
Just before, it is mixed and blown into the rotary kiln 8 '. The blowing direction does not pass through the central axis of the rotary kiln 8 ′ and is oblique to the wall surface in the traveling direction. Therefore, a swirling flame or a tubular flame is generated in the rotary kiln 8 '.

Since the ash heat treatment furnace is of the rotary kiln type, the ash heat treatment furnace inclines downward toward the downstream side and rotates, so that even if unsuitable materials for heat treatment are present, they are not retained in the furnace and incinerated. Ash can be forcibly transported downstream. In addition, dust attached to the inner wall of the ash heat treatment furnace is detached by its own weight when it reaches a certain size and is conveyed to the downstream side, so that cleaning inside the ash heat treatment furnace is not necessary and labor saving can be realized.

FIG. 7 is a schematic diagram of a circulation system for combustion gas in a furnace and combustion exhaust gas using an ejector device which is an example of the embodiment of the present invention. In FIG. 7, 34, 35
Is an ejector. A part of the combustion exhaust gas (ERG) after the secondary combustion is performed near the inlet of the exhaust heat boiler 18 is guided to the ejector 34 through the exhaust gas circulation pipe. High-temperature air (above the ignition temperature of the combustion exhaust gas) is blown into the ejector 34 as a driving flow,
The ERG is sucked by the ejector 34, mixed with the hot air, and blown into the main combustion chamber 3.

Further, a part of the primary combustion exhaust gas (unburned gas in the furnace) generated in the main combustion chamber 3 is taken out by a pipe and guided to the ejector 35. The ejector 35 is blown with high-temperature air (above the ignition temperature of the unburned gas in the furnace) as a driving flow, and the primary combustion exhaust gas is sucked into the ejector 35 and mixed with the high-temperature air to the ash heat treatment furnace 8. Is blown in.

The ejector device has a simple structure and dust in the exhaust gas is unlikely to adhere to it.
It is preferable to use an ejector having a simple structure in which a high temperature air pipe is inserted into the exhaust gas pipe and the primary combustion gas pipe, and high temperature air is ejected along the primary combustion gas pipe direction in the exhaust gas pipe. Further, it is preferable that the exhaust gas pipes are bent as little as possible to prevent dust in the exhaust gas from adhering to these pipes. Further, it is preferable to attach a pulse burner to the exhaust gas pipe to generate a pulsating flow in the exhaust gas in the exhaust gas pipe to suppress dust adhesion.

If an induction fan is provided in the exhaust gas emission system shown in FIG. 2, that is, during the process from the incinerator to the chimney, the exhaust gas downstream of the induction fan may be used instead of the hot air. it can. In particular, when the induction fan is provided in the latter stage of the exhaust gas treatment equipment, the exhaust gas downstream of the induction fan is dust-removed in the exhaust gas treatment equipment and has pressure, so that it is used as a drive flow for the ejector. It is suitable. This eliminates the need for a dedicated blower for circulating exhaust gas, which reduces equipment costs and power consumption. Also,
Since the sensible heat of the exhaust gas that becomes the driving flow can be recovered, the thermal efficiency can be increased and energy saving can be implemented. Furthermore, since the residual O ₂ in the exhaust gas can be used as O ₂ for combustion in the incinerator, the amount of supply air can be reduced,
The amount of exhaust gas can also be reduced. Therefore, energy saving and CO ₂ countermeasure can be realized.

[0095] Although not shown, O ₂ meter atmosphere in the ash heat treatment furnace 8, CO meter, detects the CO ₂ meter or the like, as the furnace atmosphere is kept reducing, the main combustion chamber 3 From an auxiliary combustion burner (not shown) installed in the main combustion chamber 3, oxidizer such as hot air blown into the main combustion chamber 3, or oxidation of auxiliary combustion gas or high temperature air blown into the ash heat treatment furnace 8 from the gas outlet 20. An ash heat treatment furnace atmosphere adjusting device for adjusting any of the agents may be provided. In this way, by positively maintaining the atmosphere in the ash heat treatment furnace 8 in a reducing atmosphere, volatilization of heavy metals in ash can be promoted and the decomposition efficiency of dioxins can be enhanced. Further, since the reducing atmosphere is present in the vicinity of the inner wall of the ash heat treatment furnace, the inner wall can be prevented from burning.

[0096]

As described above, according to the present invention, the waste incinerator and the ash heat treatment furnace are directly connected to each other, and a part of the unburned gas generated in the incinerator, high temperature air and oxygen enriched air. The main drawback of the prior art is that the ash produced while incinerating the waste is continuously heat-treated by swirling and blowing the highly reactive oxidizer into the ash heat treatment furnace. It was possible to avoid partial solidification of slag based on the non-uniformity of temperature distribution in the ash heat treatment furnace and blockage of the sprue due to changes in the properties of incinerator exhaust gas as a heat source and the properties of unburned ash in the incinerator ash. Time-stable operation and longer life of furnace material can be realized, and energy and labor can be saved as a total system.

In particular, by setting the temperature in the ash heat treatment furnace to a temperature above the decomposition temperature of dioxin and below the melting point of ash, dioxins can be decomposed without causing problems due to melting and solidification of ash. It can vaporize harmful heavy metals.

Further, by applying a highly reactive oxidant, auxiliary fuel, or swirl combustion for the ash heat treatment furnace, stable combustion in the furnace is promoted, and dioxins, C
The emission concentration of harmful substances such as O can be kept low, the control of the furnace can be facilitated, and the burnout of the inner wall can be avoided.

Furthermore, by additionally applying a heat treatment inadequate removal device, an adjustment damper, or a rotary kiln type furnace for the ash heat treatment furnace, the heat is effectively transferred to the incineration ash to be heat treated and the ash heat treatment furnace is used. There is no slag solidification problem inside, and the effect is that the operating rate is significantly improved.

On the other hand, by adopting a tapered furnace shape as a means for suppressing the scattering of ash from the ash heat treatment furnace outlet, the swirling flow velocity is remarkably increased downstream, so that the ash collection efficiency on the inner wall is increased. And the effect of promoting complete combustion in the furnace.

When the exhaust gas circulation type incinerator is applied, the exhaust gas circulation blower for the incinerator and the downstream end of the ash heat treatment furnace are used as means for drawing the high temperature unburned exhaust gas in the incinerator into the ash heat treatment furnace. By connecting it, stable operation can be realized for a long time without applying a special high temperature blower.

When the high-temperature air generator is applied to the ash heat treatment furnace, the combustible gas generated in the incinerator is circulated without the circulation blower by utilizing the eject effect of the high temperature air on the inlet side of the ash heat treatment furnace. Can be pulled into the ash heat treatment furnace. By using the high-temperature exhaust gas discharged from the high-temperature air generator to improve the mixing property in the incinerator, the pollution of the incinerator exhaust gas is reduced and the sensible heat of the exhaust gas is effectively used (heat is generated in the boiler downstream of the incinerator). Energy saving can be realized by collection).

Further, by blowing the carbon-containing fuel into the ash heat treatment furnace, the vicinity of the inner wall can be selectively heated, and since the ash is heat-treated in the reducing atmosphere, the decomposition efficiency of dioxins in the ash is improved. And the durability of the furnace material is further improved.

Further, by using an ejector device which uses high temperature air as a driving flow, exhaust gas of the waste incinerator is conveyed and blown into the waste incinerator, or combustible gas generated in the waste incinerator. By conveying and blowing it into the ash heat treatment furnace, low air ratio combustion is possible and the amount of exhaust gas can be reduced, leading to energy saving. In addition, since the flame inside the furnace is stable, low pollution can be realized. Further, since the power required for exhaust gas circulation is small, energy can be saved, and high-temperature dust-containing gas can be stably transported, so that thermal efficiency is improved and energy saving can be realized in this respect as well.

Furthermore, by using the exhaust gas downstream of the induction fan installed in the exhaust gas diffusion system instead of the hot air as the driving flow, not only the equipment cost can be reduced but also the electric power can be reduced. In addition, thermal efficiency can be increased and energy saving can be implemented. Furthermore, since the residual O ₂ in the exhaust gas can be used as O ₂ for combustion in the incinerator,
The amount of supplied air can be reduced, and the amount of exhaust gas can be reduced. Therefore, energy saving and CO ₂ countermeasure can be realized.

Further, by providing a device for adjusting at least one of the fuel and the oxidant so that the atmosphere in the ash heat treatment furnace is kept reducing, the volatilization of heavy metals in the ash is promoted, and The decomposition efficiency of dioxins can be increased. Further, since the reducing atmosphere is present in the vicinity of the inner wall of the ash heat treatment furnace, the inner wall can be prevented from burning.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an embodiment of the present invention.

2 is an example of an embodiment of the present invention waste incineration ·
It is a diagram showing a system of exhaust gas, steam, etc. in the ash heat treatment furnace.

FIG. 3 is a diagram showing details of an example of an ash heat treatment furnace which is an example of the embodiment of the present invention.

FIG. 4 is a diagram showing details of a connecting portion between a tapered flue, a heat treatment inappropriate substance detection / removal unit, and an ash heat treatment furnace in an example of an embodiment of the present invention.

FIG. 5 is a diagram showing details of a heat treatment inappropriate object detection / removal unit in an example of an embodiment of the present invention.

FIG. 6 is a diagram showing an example of an embodiment of the present invention in which the ash heat treatment furnace is a rotary kiln type.

FIG. 7 is a schematic diagram showing a circulation system of in-furnace combustion gas and combustion exhaust gas using an ejector device according to an example of an embodiment of the present invention.

FIG. 8 is a diagram showing an example of a conventional waste incineration melting furnace.

[Explanation of symbols]

1 ... Hopper, 2 ... Garbage, 3 ... Main combustion chamber, 4 ... Incinerator ash, 5
... Tapered flue, 6 ... Heat treatment unsuitable object detection / removal section, 7 ... Lattice, 8 ... Ash heat treatment furnace, 8 '... Rotary kiln, 9 ... Slag, 10 ... Slag conveyor, 11 ... Slag reservoir, 12
... Adjustment damper, 13 ... Dust remover, 14 ... Heat exchanger, 15 ...
Exhaust gas circulation blower, 16 ... Middle ceiling, 18 ... Exhaust heat boiler, 19 ... Outlet of stirred gas in furnace, 20 ... Gas outlet,
21 ... Gas inlet in the incinerator, 22 ... High temperature air inlet, 23 ... Outlet, 24 ... High temperature air generator, 25 ... Hazardous substance supply device, 26 ... TV camera, 27 ... Pusher, 2
8 ... Cooling air inlet, 29 ... Shielding plate, 30 ... Cover, 3
DESCRIPTION OF SYMBOLS 1 ... Excitation device, 32 ... Roller, 33 ... Mixed gas blowing port, 34, 35 ... Ejector

Front Page Continuation (72) Inventor Kazuhiro Teratsuji 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Steel Pipe Co., Ltd. (56) Reference JP-A-6-307614 (JP, A) JP-A-8-35406 (JP, A) JP 10-2530 (JP, A) JP 8-110025 (JP, A) JP 9-133331 (JP, A) JP 9-196349 (JP, A) Kaihei 5-256431 (JP, A) JP 5-141633 (JP, A) JP 9-26124 (JP, A) JP 9-236242 (JP, A) JP 10-103634 ( JP, A) JP 10-227431 (JP, A) JP 8-200638 (JP, A) JP 10-103635 (JP, A) JP 10-227434 (JP, A) JP 55-140026 (JP, A) JP-A-53-98171 (JP, A) JP-A-51-115335 (JP, A) JP-A-54-144770 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) F23J 1/00 F23G 5/00 115 F23G 5/027 F23G 5/16 F23G 5/44

Claims (19)

(57) [Claims] 1. A waste incinerator and an ash heat treatment furnace are directly connected,
A waste incineration / heat treatment furnace that incinerates waste and heats the ash generated at that time at a temperature not higher than the melting temperature of the ash, and burns some of the combustible gas generated in the waste incinerator and fuel. With the high temperature air generated from the high temperature air generator that burns and heats the air, the swirling flame or tubular flame in the ash heat treatment furnace,
It is characterized by heating the inner wall of the ash heat treatment furnace by the swirling flame or tubular flame at a high speed so that it is formed in a direction perpendicular to the flow of the exhaust gas and the incinerated ash so as to be formed in the direction along the furnace wall. Waste incineration and heat treatment furnace. 2. The waste incineration heat treatment furnace according to claim 1, wherein the high-temperature air generator heats air with a fuel, and high-temperature combustion exhaust gas of the fuel is supplied to the incinerator of the 2 A waste incineration / heat treatment furnace, which can be used as a gas for stirring the inside of the incinerator by swirling and blowing into the next combustion area. 3. A waste incinerator and an ash heat treatment furnace are directly connected to each other,
A waste incineration / heat treatment furnace that incinerates waste and heats the ash generated at that time at a temperature not higher than the melting temperature of the ash, with some of the combustible gas generated in the waste incinerator and oxygen concentration. With the oxidant adjusted, the swirling flame or tubular flame in the ash heat treatment furnace, in the direction perpendicular to the flow of the exhaust gas and the incinerated ash,
A waste incineration / heat treatment furnace characterized by being blown at a high speed so that the inner wall of the ash heat treatment furnace is heated by the swirling flame or tubular flame so as to be formed in the direction along the furnace wall. 4. The waste incineration / heat treatment furnace according to claim 3, wherein a mixed gas of a part of the exhaust gas generated in the waste incinerator and oxygen can be used as an oxidant. Waste incineration and heat treatment furnace to be. 5. Any one of claims 1 to 4
The waste incineration / heat treatment furnace according to the item 1, wherein the temperature of the high-temperature air or the oxidizer whose oxygen concentration is adjusted is adjusted so as to keep the temperature in the ash heat treatment furnace at a predetermined value. Waste incineration and heat treatment furnace to be. 6. Any one of claims 1 to 5
The waste incineration / heat treatment furnace according to the item 1, wherein the waste incineration / heat treatment furnace is provided with an auxiliary fuel supply device for adjusting the temperature in the ash heat treatment furnace. 7. The waste incineration / heat treatment furnace according to claim 6, wherein the auxiliary fuel is a carbon-containing fuel, and means for stirring the fuel and ash is provided in the ash treatment furnace. A waste incineration / heat treatment furnace. 8. Any one of claims 1 to 7
Item 5. The waste incineration / heat treatment furnace according to the item 1, wherein the downstream side of the ash heat treatment furnace is tapered toward the outlet. 9. Any one of claims 1 to 8
The waste incineration / heat treatment furnace according to paragraph (1), wherein a hazardous waste supply device is disposed in or upstream of the ash heat treatment furnace so that harmful waste in a gas, liquid, or particulate form can be blown in, A waste incineration / heat treatment furnace characterized in that an exhaust gas treatment device is disposed downstream of the ash heat treatment furnace. 10. The waste incineration / heat treatment furnace according to any one of claims 1 to 9, wherein heat treatment inappropriate substances in incinerated ash are detected upstream of the ash heat treatment furnace. A waste incineration / heat treatment furnace characterized by being equipped with an unsuitable substance removing device. 11. The waste incineration / heat treatment furnace according to any one of claims 1 to 10, wherein the ash heat treatment furnace is a rotary kiln type ash heat treatment furnace. Material incineration / heat treatment furnace. 12. A waste incineration / heat treatment furnace in which a waste incinerator and an ash heat treatment furnace are directly connected to incinerate waste and heat-treat ash generated at that time at a temperature not higher than the melting temperature of ash,
A damper for suppressing the inflow of incinerator exhaust gas from the waste incinerator to the ash heat treatment furnace is provided in the communication part between the waste incinerator and the ash heat treatment furnace. A waste incineration / heat treatment furnace characterized in that the damper opening is adjusted to be slightly higher than the internal pressure of the incinerator. 13. The waste incineration / heat treatment furnace according to any one of claims 1 to 12, wherein the exhaust gas of the waste incinerator is conveyed by using high temperature air as a driving flow, and the waste is discharged. A waste incinerator / heat treatment furnace characterized by being equipped with an ejector device for blowing air into the incinerator. 14. The waste incineration / heat treatment furnace according to claim 1, wherein the combustible gas generated in the waste incinerator is driven by high temperature air. A waste incineration / heat treatment furnace characterized by being provided with an ejector device for carrying and blowing it into the ash heat treatment furnace. 15. A waste characterized by using exhaust gas downstream of an induction fan installed in an exhaust gas emission system, in place of high temperature air in the waste incineration / heat treatment furnace according to claim 13 or 14. Material incineration / heat treatment furnace. 16. A waste incineration / heat treatment furnace in which a waste incinerator and an ash heat treatment furnace are directly connected to incinerate waste and heat-treat ash generated at that time at a temperature not higher than the melting temperature of ash,
The waste incinerator is an exhaust gas circulation type incinerator, and the exhaust gas of the ash heat treatment furnace is sucked by the exhaust gas circulation blower of the waste incinerator , and along with it, unburned gas in the upstream region of the waste incinerator. A waste incineration / heat treatment furnace , wherein gas is drawn into the ash heat treatment furnace via a bypass . 17. The waste incineration / heat treatment furnace according to any one of claims 1 to 11, wherein the waste incinerator is an intermediate ceiling in a primary combustion chamber (main combustion chamber). A double-flow grate incinerator equipped with, wherein the combustible gas is a gas stream separated by the intermediate ceiling, and a part of the exhaust gas on the side containing a large amount of unburned gas is extracted. Waste incineration and heat treatment furnace to be. 18. The waste incineration / heat treatment furnace according to any one of claims 1 to 17, wherein the temperature in the ash heat treatment furnace is 800 ° C. or higher and lower than the ash melting temperature. A waste incineration / heat treatment furnace, which is provided with a temperature control device for controlling. 19. The waste incineration / heat treatment furnace according to claim 1, wherein the ash heat treatment furnace is provided with a fuel and an oxidizer so that the inside of the ash heat treatment furnace has a reducing atmosphere. A waste incineration / heat treatment furnace, which is equipped with a device for adjusting at least one of them.