JP2002276912A - Method and apparatus for incinerating waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for incinerating a waste capable of completely incinerating the waste without generating not only a smoke but also an environmental pollutant such as dioxins or the like irrespective of the type of an object to be incinerated and a small-sized apparatus for incinerating the waste suitable for executing the method. SOLUTION: The method for incinerating the waste comprises a first step of generating a combustible gas by thermally decomposing the waste in a primary furnace chamber and burning a remaining decomposion residue, a second step of completely burning the combustible gas at a temperature in a range of 800 to 1,000 deg.C by introducing the gas into a secondary furnace chamber, and a third step of injecting and mixing hot water or steam into a combustion gas flowing out from the secondary chamber in an exhaust duct and quenching the temperature of the gas to 200 deg.C or lower. Particularly, in the second step, it is preferred that the combustible gas is introduced into the secondary chamber in a state in which the gas is ignited, the combustible gas is mixed with an aqueous liquid of a scavenger for a sulfur oxide or a hydrogen chloride, the combustible gas is introduced to the peripheral wall of the secondary chamber in a tangential direction, and burned while being turned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to industrial waste such as construction waste, waste plastic, waste tires, waste oil, forestry waste, agricultural waste, and other industrial waste, and general waste such as urban waste including kitchen waste. The present invention relates to a waste incineration method for safely burning incineration without causing environmental pollution due to dust, smoke, harmful gas and the like, and a waste incineration apparatus suitable for carrying out such incineration method.

[0002]

2. Description of the Related Art Various types of incinerators have been proposed as incinerators for various wastes, from large continuous incinerators to small batch incinerators. However, in general, waste brought into an incineration plant often contains miscellaneous items, and the combustion conditions tend to fluctuate. Therefore, incomplete combustion produces smoke and dust, or harmful gas. There is a problem that it is easy to cause environmental pollution. Therefore, in recent incinerators, the combustion temperature has been increased to achieve complete combustion, and sulfur oxides, nitrogen oxides, chlorine compounds, etc. have been captured and removed from the combustion gas to make the exhaust gas harmless. Improvements are underway.

However, in order to thoroughly manage such incineration conditions and detoxify the combustion gas, it is necessary to increase the size of the incineration equipment and arrange complicated equipment on a large site, which increases construction costs. Therefore, even if it is suitable for continuously processing a large amount of waste, it is difficult to achieve both complete combustion and detoxification of combustion gas with a small incinerator that processes a small amount of waste. And it was.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a small-sized, compact combustion system capable of achieving complete combustion without producing smoke, suppressing the production of harmful dioxins and the like, and easily removing other harmful gases. It is an object of the present invention to provide a waste incineration method and a waste incineration apparatus that can perform incineration regardless of the type of an object to be incinerated.

[0005]

A waste incineration method which can achieve the above object of the present invention is to decompose waste in a primary furnace chamber to generate combustible gas and burn remaining decomposition residues. A first step of introducing the combustible gas into the secondary furnace chamber and completely burning the combustible gas in a temperature range of 800 to 1000 ° C., and a combustion gas flowing out of the secondary furnace chamber in an exhaust duct. A third step of quenching the temperature of the combustion gas to 200 ° C. or lower by injection mixing hot water or steam.

In the second step, if the flammable gas is mixed with secondary air and ignited and introduced into the secondary furnace chamber, the preheating time of the secondary furnace chamber can be shortened and the load of gas combustion can be reduced. As a result, the overall incineration efficiency can be improved, and further, by injecting and mixing an aqueous liquid containing a trapping agent for either sulfur oxide or hydrogen chloride into the combustible gas introduced into the secondary furnace chamber. , A high degree of purification of combustion gases can be achieved.

In the second step, the combustible gas is introduced tangentially to the peripheral wall of the secondary furnace chamber and swirled along the peripheral wall so that the dust is completely burned while being separated. In addition, the gas combustion efficiency in the secondary furnace chamber is improved, and at the same time, the combustion temperature is raised, so that generation and leakage of dioxin and other environmental pollutants can be effectively suppressed.

A waste incineration apparatus suitable for carrying out the above-described waste incineration method of the present invention burns a part of the waste and thermally decomposes the remaining part to generate a primary gas that generates combustible gas or combustion gas. A furnace chamber, a secondary furnace chamber that introduces the combustible gas or combustion gas to completely burn, a combustible gas duct that introduces the combustible gas or combustion gas generated in the primary furnace chamber into the secondary furnace chamber, An incinerator provided with an exhaust duct for cooling and sending out combustion gas flowing out of the secondary furnace chamber, wherein at least one of the primary furnace chamber, the combustible gas duct, the secondary furnace chamber, and the exhaust duct is provided. Has a water-cooled jacket, and steam or hot water generated from any of the water-cooled jackets can be blown into the exhaust duct.

In the waste incinerator according to the present invention, the secondary furnace chamber has a conical upper wall body vertically connected to the exhaust duct at a center position, and an inverted cone shape having an ash outlet formed at a center position. A vertical cylindrical combustion space divided into upper and lower parts by a bottom partition body, and the flammable gas duct is configured to be tangentially connected to a peripheral wall of the combustion space, so that the secondary furnace chamber The combustion efficiency of the introduced combustible gas is increased, unburned components are not left, and the generation of harmful components such as dioxin is suppressed.

Further, when the combustible gas duct is provided with an ignition means, not only there is no danger of incomplete combustion gas being discharged when the waste incinerator of the present invention starts operation, but also the secondary furnace chamber There is an advantage that preheating is completed in a short time and full-scale operation can be started promptly.

Further, if the combustible gas duct is provided with means for jetting and mixing an aqueous liquid containing a trapping agent for either sulfur oxide or hydrogen chloride, there is no effect on the combustion decomposition of waste in the primary furnace chamber. This has the advantage that sulfur oxides or hydrogen chloride in the combustible gas can be trapped without affecting the environment, and environmental pollutants in the combustion gas discharged from the secondary furnace chamber can be significantly reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a waste incinerator according to the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a primary furnace chamber, reference numeral 2 denotes a combustible gas duct for sending out combustible gas generated in the primary furnace chamber 1, and reference numeral 3 denotes a secondary furnace chamber for burning combustible gas sent from the combustible gas duct 2. Reference numeral 4 denotes an exhaust duct provided at an upper part of the secondary furnace chamber 3.

The primary furnace chamber 1 includes a cylindrical primary furnace body 1a having a water-cooled jacket 1b and a detachable lid 1c. The bottom of the primary furnace body 1a is narrowed in an inverted conical shape. And a primary air introduction chamber 1d is formed through the grate,
Combustion air is supplied by the primary blower 1e. A part of the waste put into the primary furnace body 1a is burned and thermally decomposed to be carbonized. As a result, the generated gas component is converted into a flammable incomplete combustion gas as the primary furnace. It is configured to flow out to an inflammable gas duct 2 from an opening provided in a side wall of the body 1a.

The flammable gas duct 2 connected to the opening of the primary furnace body 1a has a water-cooled jacket 2a and an air introduction nozzle 2c for introducing the secondary air supplied by the secondary blower 2b. A trapping agent tank 2d and a trapping agent injection nozzle 2e for injecting a trapping agent for a sulfur oxide, hydrogen chloride, or the like into a combustible gas or a combustion gas are provided. Further, near the rear end of the combustible gas duct 2, an auxiliary burner 2f for igniting the combustible gas passing through the inside is provided, and the rear end of the combustible gas duct 2 is provided with a gas inlet 3g of the secondary furnace chamber 3. It is connected to the. Therefore, the combustible gas flowing in the combustible gas duct 2 can be introduced into the secondary furnace chamber 3 in a state where combustion has started.

The secondary furnace chamber 3 is provided with a water-cooled jacket 3b.
And a conical upper wall 3c having a water-cooled jacket 3d and dividing the upper part of the secondary furnace body 3a. A lower part of the secondary furnace body 3a An inverted conical bottom partition 3e having an ash outlet 3f is provided at a center position so that dust and the like separated from the combustion gas can be taken out from under the bottom partition 3e.

The gas inlet 3g provided on the side wall of the secondary furnace body 3a is formed in a wide and oval shape, and as shown in FIG. 3a
Is configured to be introduced substantially tangentially to the side wall of the secondary furnace 3a, so that it is swirled in the space inside the secondary furnace body 3a and burns. Therefore, the dust in the combustion gas is separated by the centrifugal force due to the swirling, and settles down along the peripheral wall, and the bottom partition 3e
From the ash exit 3f. On the other hand, the combustion gas from which the dust is separated and removed rises while swirling in the space inside the secondary furnace body 3a, and is discharged into the exhaust duct 4 connected to the center of the conical upper wall body 3c. Is done.

The exhaust duct 4 is provided with a water-cooled jacket 4a.
And is erected at a position coaxial with the secondary furnace body 3a upward from the center of the upper wall body 3c. At the lower part of the exhaust duct 4, as shown in FIG. 3, a steam nozzle 4b is provided from the periphery toward the internal space, and is generated from at least one of the jackets 1b, 2a, 3b, 4a. Steam is supplied to the steam nozzle 4b,
Mixed with the high-temperature combustion gas discharged from the secondary furnace body 3a,
It acts to rapidly lower the temperature of the combustion gas. Reference numeral 5 denotes a lid for closing the outlet of the exhaust duct 4 when the device is not used.

The gas discharged from the exhaust duct 4 having the above-described structure may be used, if necessary, in a dust collection device, a heat recovery device,
Alternatively, the waste can be sent to a gas purification device or the like for treatment. However, in the waste incineration device of the present invention, if it is operated according to appropriate operating conditions, that is, if the waste incineration method of the present invention is carried out, environmental pollutants , And can be directly discharged into the atmosphere without any additional processing.

In the waste incinerator of the present invention, the primary furnace chamber 1, the combustible gas duct 2, the secondary furnace chamber 3, and the exhaust duct 4 are provided with water-cooled jackets 1b, 2a, 3a, respectively.
b and 4a are provided to prevent each device from being deteriorated by being exposed to a high temperature. Accordingly, hot water or steam is generated in each of these jackets. Therefore, part of the steam or hot water is used to cool the combustion gas passing through the exhaust duct 4 as described above, and the remaining hot water or hot water is sent to the cooling water tank 6 and re-used. It is to be stored for use.

Next, the waste incineration method of the present invention using the above waste incineration apparatus will be described. The waste that can be treated by the method of the present invention may be any flammable material that can be incinerated, such as municipal waste including kitchen waste and general industrial waste. In other words, in conventional garbage incineration plants, etc., the amount of heat generated is too large to damage the furnace, the furnace is damaged by the generation of harmful gas, or it is difficult to completely collect the generated harmful gas. Even if the waste has been excluded from the incineration, any article that is decomposed and burned by heating can be handled as a treatment target in the present invention.

The waste to be treated is charged into the primary furnace 1a by opening the cover 1c of the primary furnace chamber 1 and treating the waste at one time. Thereafter, the lid 1c of the primary furnace chamber 1 is closed, the waste is ignited using an ignition burner or the like introduced into the primary air introduction chamber 1d, and the primary blower 1e is operated to activate the primary air introduction chamber. Send primary air into 1d. Then, a part of the waste starts burning, and the heat of the combustion heats the other part of the waste. As a result, thermal decomposition occurs to reach 400 ° C. or more, and the generation of combustible gas and the generation of carbides occur. You will proceed at the same time.

The combustible gas generated by the thermal carbonization of the waste flows out from the opening of the primary furnace chamber 1 into the combustible gas duct 2. Then, near the front end of the combustible gas duct 2, it mixes with the secondary air supplied from the air introduction nozzle 2 c and flows toward the secondary furnace chamber 3. Then, the auxiliary burner 2f provided near the rear end of the combustible gas duct 2 ignites by receiving additional combustion auxiliary air as necessary, and in some cases, the flame spreads to the entire inside of the combustible gas duct 2, The combustion gas flows into the secondary furnace chamber 3.

The combustible gas generated by the thermal decomposition in the primary furnace chamber 1 and flowing into the combustible gas duct 2 may contain a sulfur compound or a chlorine compound. Such sulfur compounds and chlorine compounds usually change into acidic gases such as sulfur dioxide and hydrogen chloride in the presence of oxygen. Therefore, a scavenger provided in the combustible gas duct 2 to trap and remove these acidic gases. The injection nozzle 2e is used to inject an acidic gas scavenger into the combustible gas duct 2 so as to be in contact with the combustible gas.

The scavenger used here is preferably a hydroxide or an organic acid salt of an alkali metal or an alkaline earth metal. For example, an aqueous solution of calcium formate or calcium acetate is prepared in the scavenger tank 2d. It is preferable to inject and inject into the combustible gas through the scavenger injection nozzle 2e. By performing such treatment, the acidic gas component in the combustible gas becomes powder such as calcium sulfite or calcium chloride and flows into the secondary furnace chamber 3 together with the non-combustible dust in the combustion gas.

The combustion gas that has flowed into the secondary furnace chamber 3 as described above swirls along the peripheral wall of the secondary furnace body 3a, and the combustion gas flows into the secondary furnace body 3a, the upper wall body 3c, the bottom partition body 3e. And flows toward the exhaust duct 4. Therefore, the amounts of the primary air and the secondary air are adjusted, and the amount of the auxiliary combustion air supplied from the position of the auxiliary burner 2f is adjusted to suppress the combustion inside the combustible gas duct 2 and to reduce the amount of the secondary furnace chamber. 3 to promote the combustion inside, the combustion temperature in the secondary furnace chamber 3,
The temperature is adjusted to 800 ° C. or higher, preferably 800 to 1000 ° C., and the combustible gas is completely burned.

In such a stable combustion state, the flow of the combustion gas in the secondary furnace chamber 3 becomes a swirling flow along the peripheral wall, so that the dust in the combustion gas moves toward the peripheral wall by centrifugal force, and Separated from the gas, it further falls along the peripheral wall, reaches the bottom partition 3e, falls down from the ash outlet 3f, and accumulates. In addition, since the combustion temperature is as high as 800 to 1000 ° C., most of the harmful organic compounds such as dioxin are in a decomposed state, and the harmful substances as described above may remain in the separated dust. Absent.

As described above, the combustion gas having a temperature of 800 ° C. or higher flowing from the secondary furnace chamber 3 into the exhaust duct 4
It is mixed with steam or hot water injected from the lower steam nozzle 4b and quenched to 200 ° C. or less. Even if the combustion gas after being quenched in this way contains a substance that causes the generation of dioxin or the like,
Since it passes through a temperature range for generating dioxin or the like in a short time, dioxin or the like is hardly contained, and there is no need for post-treatment for cleaning, so that it can be safely discharged as it is.

[0028] In the waste incineration method of the present invention, the properties of the pyrolysis residue in the primary furnace chamber differ depending on the properties of the waste that can be treated. The gas is not accompanied by smoke or dust,
It is easy to burn completely. And, as for the pyrolysis residue, those with high carbon content can be used as valuable resources such as activated carbon and soil conditioner, and those with low carbon content can be oxidized and burned to the end to recover as thermal energy,
Alternatively, it can be disposed as a reduced residue without being collected.

The ash recovered in the secondary furnace chamber is converted into inorganic substances or sublimable metal oxides, which are obtained by combining sulfur compounds and chlorine compounds in waste with these scavengers, when combustible gas is burned. It is thought that it is almost free from harmful substances in view of the combustion temperature conditions of the secondary furnace chamber because the generated carbon and the like are combined. Moreover, under the above combustion temperature conditions, it is considered that there is no generation of nitrogen oxides and dioxins, and all of the emissions when the waste incineration method of the present invention is carried out are of high safety without fear of environmental pollution. Can be said to be.

[0030]

According to the waste incineration method of the present invention, an incinemable organic waste is pyrolyzed to generate a combustible gas and a solid residue containing carbon, and then each is incinerated. It is converted into harmless exhaust gas and harmless residue or useful carbon products.The exhaust gas does not contain environmental polluting gases such as hydrogen chloride, sulfur oxides, nitrogen oxides, and harmful substances such as dioxins. There is an effect that no substance is contained and no emission of dust occurs. And the waste incineration apparatus of the present invention suitable for carrying out the waste incineration method of the present invention is small and has high performance, and various kinds of waste having different properties can be produced without causing environmental pollution. It has the advantage that it can be incinerated, has less restrictions on the installation site of the device, has less construction cost, is easy to operate, and is economical.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing the configuration of a waste incinerator according to the present invention.

FIG. 2 is a cross-sectional view showing a structure of a joint portion between a combustible gas duct and a secondary furnace chamber in the waste incinerator of the present invention.

FIG. 3 is a cross-sectional view showing a lower structure of an exhaust duct in the waste incinerator according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary furnace chamber 1b Jacket 1a Primary furnace body 1c Lid 1d Primary air introduction chamber 1e Primary blower 2 Combustible gas duct 2a Jacket 2b Secondary blower 2c Air introduction nozzle 2d Capture agent tank 2e Capture agent injection nozzle 2f Auxiliary burner 3 Secondary furnace Chamber 3a Secondary furnace 3b Jacket 3c Upper wall 3d Jacket 3e Bottom partition 3f Ash outlet 3g Gas inlet 4 Exhaust duct 4a Jacket 4b Steam nozzle 5 Lid 6 Cooling water tank

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B09B 3/00 302 F27D 17/00 101Z 4D004 104G 4D031 F23G 5/16 ZAB 105G 4K056 5/44 ZAB B01D 53 / 34 124Z F23J 15/06 134A 15/00 B09B 3/00 303J F27D 17/00 101 F23J 15/00 K 104 B 105 Z F term (reference) 3K061 AA23 AB02 AC01 AC06 AC13 AC17 BA04 CA01 FA08 FA21 FA23 FA28 UA05 UA12 UA16 UA12 UA16 UA23 3K065 AA23 AB02 AC01 AC06 AC13 AC17 BA04 HA02 3K070 DA03 DA05 DA16 DA23 DA39 3K078 AA04 BA03 BA21 BA26 CA02 CA07 CA11 CA17 CA21 4D002 AA02 AA19 AB01 AC04 BA03 CA01 DA01 DA04 DA05 DA19 EA02 4A004 AA03 A31 A32 A31 AA31A32 CB34 CC03 4D031 AC04 4K056 AA19 BA01 BB01 CA20 DA02 DA15 DA31 DB01 DB07 DC05 EA01

Claims (8)

[Claims] 1. A first method for thermally decomposing waste in a primary furnace chamber to generate combustible gas and burning remaining decomposition residues.
And introducing the combustible gas into the secondary furnace chamber for 800 to 10
A second step of completely burning in a temperature range of 00 ° C., and injecting hot water or steam into the exhaust gas into the combustion gas flowing out of the secondary furnace chamber in an exhaust duct to lower the temperature of the combustion gas to 200 ° C. or less. And a third step of quenching so as to obtain a waste incineration method. 2. The waste incineration method according to claim 1, wherein, in the second step, the combustible gas is mixed with secondary air and then ignited and introduced into the secondary furnace chamber. 3. In the second step, an aqueous liquid containing a scavenger for either sulfur oxide or hydrogen chloride is injected and mixed into the combustible gas introduced into the secondary furnace chamber. The waste incineration method according to claim 1 or 2. 4. The method of claim 2, wherein in the second step, the combustible gas is introduced tangentially to a peripheral wall of the secondary furnace chamber, and swirled to completely combust dust. 4. The waste incineration method according to any one of 1 to 3. 5. A primary furnace chamber for burning a part of the waste and thermally decomposing the remaining part to generate a combustible gas or a combustion gas, and a secondary furnace for introducing the combustible gas or the combustion gas to complete combustion. A combustion chamber, a combustible gas duct for introducing the combustible gas or combustion gas generated in the primary furnace chamber into the secondary furnace chamber, and an exhaust duct for cooling and sending out the combustion gas flowing out of the secondary furnace chamber. In the incinerator, at least one of the primary furnace chamber, the combustible gas duct, the secondary furnace chamber, and the exhaust duct includes a water-cooled jacket, and steam or hot water generated from any of the water-cooled jackets. Characterized by being able to blow air into the exhaust duct. 6. The secondary furnace chamber includes a conical upper wall body vertically penetrating and connecting the exhaust duct at a central position, and an inverted conical bottom partition body having an ash outlet at a central position. The waste incinerator according to claim 5, further comprising: a vertical cylindrical combustion space defining the combustion space, wherein the combustible gas duct is connected tangentially to a peripheral wall of the combustion space. 7. The waste incinerator according to claim 5, wherein the combustible gas duct includes an ignition means. 8. The method according to claim 5, wherein the combustible gas duct is provided with means for jetting and mixing an aqueous liquid containing a scavenger for either sulfur oxide or hydrogen chloride. Waste incineration equipment.