JP4068356B2 - Incineration residue treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an incineration residue treatment method and an improvement of an incineration residue treatment apparatus for detoxifying and effectively using incineration residues (incineration ash) discharged from incinerators such as general waste and industrial waste.
[0002]
[Prior art]
Incineration residues from incinerators are mainly landfilled in managed landfills, and some of them are melted into slag.
However, landfilling was a problem because a new disposal site could not be built near the city due to the tightness of the disposal site.
On the other hand, melting slag is becoming popular because it can make incineration residue harmless, extend the life of disposal sites, and effectively use resources. The generated slag can also be used for civil engineering materials. However, a large amount of heat energy is required, and the amount of carbon dioxide (CO ₂ ) that is a global warming gas is large, which is a problem.
[0003]
For ash cement, etc., the safety standards are dioxins (DXN) of 40 pg / g or less (standard for agricultural land in Germany) and elution of heavy metals is below the soil environmental standards. Is not mentioned at all.
However, when ash cement and the like are intended to make effective use of incineration residues widely, the content of heavy metals such as lead (Pb) as well as elution of dioxins and heavy metals has been regarded as a problem.
[0004]
By the way, as the incineration residue treatment method, for example, JP-A-6-174383, JP-A-8-182893, JP-A-10-151437, JP-A 3108061 (JP-A 2000-79381), JP-A 2000-233174. JP-A-2000-279920 and the like are known.
[0005]
[Problems to be solved by the invention]
However, none of the conventional ones are intended to make the incineration residue harmless and effectively used, but they are not safe and inexpensive.
[0006]
The present invention has been devised in view of the problems described above, and the problem to be solved is that the content of heavy metals in the incineration residue is reduced, and the safety is high and inexpensive. An object of the present invention is to provide an incineration residue treatment apparatus which makes incineration residue harmless and aims for effective use.
[0007]
[Means for Solving the Problems]
The incineration residue treatment apparatus of the present invention basically has a feature in that a chlorinating agent is added to the incineration residue, and this is calcinated and volatilized by combustion exhaust gas from the incinerator.
[0008]
From the incinerator, combustion exhaust gas and incineration residue are generated. A chlorinating agent is added to the incineration residue from the incinerator. The incineration residue to which the chlorinating agent is added is calcined by the combustion exhaust gas from the incinerator and chlorinated by the chlorination volatilization method.
For this reason, the content of heavy metals in the fired product after firing is reduced, and the concentration of dioxins is also reduced.
The combustion exhaust gas from the incinerator is used, and the incineration residue is chlorinated and volatilized based on the chlorination volatilization method. Therefore, the incineration residue can be made harmless and effectively used at a low cost.
[0009]
It is preferable to remove coarse substances, metals, and the like in the incineration residue, pulverize them, and then add a chlorinating agent to granulate. In this way, crude substances and metals can be recovered, and the chlorination volatilization due to calcination can be promoted, and the content of heavy metals and the concentration of dioxins in the incineration residue can be efficiently reduced.
[0010]
It is preferable to raise the combustion exhaust gas in the upper part of the post-combustion stoker after the incinerator to a temperature necessary for firing and to use the fired exhaust gas to the boiler. If it does in this way, while using a part of combustion exhaust gas of an incinerator, a burning energy can be reduced and the calorie | heat amount of the waste gas after baking can be collect | recovered with a boiler.
[0011]
It is preferable to age after calcining the fired product. In this way, the elution amount of heavy metals can be reduced.
[0012]
An incinerator that incinerates waste, a boiler that generates steam by the combustion exhaust gas from the incinerator, a pretreatment device that removes coarse materials and metals from the incineration residue from the incinerator, and a pretreatment device Necessary for calcination of granulator that pulverizes pre-treated product and adds chlorinating agent, calcines granulated product from granulator and volatilizes and volatilizes, and combustion exhaust gas from incinerator Auxiliary combustion device that raises the temperature to a suitable temperature and supplies it to the firing device, an exhaust gas recirculation device that guides the exhaust gas from the firing device to the boiler, a quenching device that quenches the fired product from the firing device, and an aging treatment from the quenching device It is preferable to constitute an incineration residue treatment apparatus from the aging apparatus. In this way, the structure is relatively simple and the equipment cost can be reduced.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an incineration residue treatment apparatus according to the present invention.
[0014]
The incineration residue treatment apparatus 1 is mainly composed of an incinerator 2, a boiler 3, a pretreatment apparatus 4, a granulation apparatus 5, a firing apparatus 6, an auxiliary combustion apparatus 7, an exhaust gas recirculation apparatus 8, a quenching apparatus 9, and an aging apparatus 10. It is configured.
[0015]
The incinerator 2 incinerates the waste A, and in this example, incinerates general waste and industrial waste, and combustion exhaust gas B and incineration residue C are generated. The incinerator 2 includes a waste supply device 11, a dry stoker 12, a combustion stoker 13, a post-combustion stoker 14, an incineration residue discharge port 15, a secondary combustion chamber 16, and the like.
[0016]
The boiler 3 generates steam depending on the combustion exhaust gas B from the incinerator 2.
[0017]
The pretreatment device 4 removes the coarse substance D and the metals E from the incineration residue C from the incinerator 2, and in this example, although not shown, a screen, a crushing device, a magnetic separator, an aluminum separator Etc., so that the coarse substance D and the metals E such as iron (Fe) and aluminum (Al) are removed.
[0018]
The granulator 5 pulverizes the pretreatment product F from the pretreatment device 4 and adds the chlorinating agent G, and in this example, granulation is performed. In this example, calcium chloride (CaCl ₂ ), sodium chloride (NaCl), etc. The chlorinating agent G is added and granulated (pelletized).
[0019]
The calcining device 6 calcinates the granulated material H from the granulating device 5 to volatilize and chlorinate. In this example, the calcining device 6 is a rotary kiln capable of performing the chlorination volatilization method and supplies the granulated material H. 17, a kiln cylinder 18 that calcinates and volatilizes the granulated product H from the supply feeder 17 while rotating, an inlet hood 19 that is provided upstream of the kiln cylinder 18 and discharges exhaust gas I, and a kiln cylinder 18. And an outlet hood 20 that discharges the fired product J.
Thus, the heat source of the rotary kiln 6 uses the combustion exhaust gas B from the incinerator 2, particularly the combustion exhaust gas B with relatively little dust at the upper part of the post combustion stoker 14, and the outlet hood 20 of the rotary kiln 6 An upper part of the rear combustion stoker 14 of the incinerator 2 is communicated with a communication passage 21.
[0020]
The chlorination volatilization method makes use of the property of volatilizing easily when minerals are chlorinated.For example, in the steel smelting process, various non-ferrous metals after volatilizing non-ferrous metals in the raw materials, which are regarded as impurities, into chlorides. It is a method of separating and collecting.
[0021]
The auxiliary combustion device 7 raises the combustion exhaust gas B from the incinerator 2 to a temperature necessary for firing and supplies it to the firing device 6. In this example, the auxiliary combustion device 7 is provided in the middle of the communication path 21 and is exited from the firing device 6. An auxiliary burner directed to the hood 20 is used to raise the temperature of the combustion exhaust gas B from the incinerator 2 to 900 to 1100 ° C. necessary for firing.
[0022]
The exhaust gas recirculation device 8 guides the exhaust gas I from the firing device 6 to the boiler 3. In this example, the exhaust gas reflux device 8 indirectly guides the exhaust gas I to the boiler 3. A reflux path 22 that communicates with the next combustion chamber 16, a heat exchanger 23 that is provided in the middle of the reflux path 22 to reduce the temperature of the exhaust gas I from the calcining device 6, and is provided in the middle of the reflux path 22. And a blower 24 for feeding the exhaust gas I from the heat exchanger 23 to the secondary combustion chamber 16 of the incinerator 2.
[0023]
The rapid cooling device 9 rapidly cools the fired product J from the firing device 6, and in this example, it is a water-sealed conveyor that stores cooling water and rapidly cools the fired product J accordingly.
[0024]
The aging device 10 is for aging the processed material K from the quenching device 9. In this example, the aging device 10 is a yard for storing the processed material K and is naturally aged.
[0025]
Aging refers to aging in a general environment. Carbon dioxide in the atmosphere is reacted with heavy metals in the processed material K to produce a carbonic acid compound, which is changed into a property that is difficult to elute itself. .
[0026]
Next, the operation will be described based on such a configuration.
The waste A is sent to the incinerator 2 and incinerated accordingly, and combustion exhaust gas B and incineration residue C are generated. The combustion exhaust gas B from the incinerator 2 is sent to the boiler 3 and steam is generated accordingly. The incineration residue C from the incinerator 2 is discharged as a so-called dry ash from the residue discharge port 15 and is sent to the pretreatment device 4, thereby depending on the crude material D and metals such as iron (Fe) and aluminum (Al). E is removed. The pre-treatment product F from the pre-treatment device 4 is sent to the granulation device 5 and pulverized in accordance therewith, and after adding a chlorinating agent G such as calcium chloride (CaCl ₂ ), it is granulated, that is, pelletized. .
[0027]
The granulated product H from the granulating device 5 is sent to the firing device 6 where it is fired and chlorinated. That is, when the granulated product H is calcined by the combustion exhaust gas B from the incinerator 2 in the calciner 6, the lead (Pb) in the granulated product H is volatilized into the gas layer by the chloride volatilization method. At the same time, dioxins (DXN) in the granulated product H are also decomposed. At this time, the combustion exhaust gas B from the incinerator 2 is heated to 900 to 1100 ° C. necessary for firing by the auxiliary combustion device 7 through the communication path 21 and then supplied to the firing device 6.
[0028]
The exhaust gas I from the calcining device 6 is returned to the secondary combustion chamber 16 of the incinerator 2 by the reflux path 22 of the exhaust gas recirculation device 8. At this time, the temperature is reduced by the heat exchanger 23 of the exhaust gas recirculation device 8 and is supplied by the blower 24. The fired product J from the firing device 6 is sent to the quenching device 9 and rapidly cooled accordingly. The processed material K from the rapid cooling device 9 is sent to a yard which is an aging device 10 and stored therein, and aging is performed accordingly. In other words, the heavy metal in the treated product K is converted into an insoluble stable reaction product (aging treated product) by being carbonated.
[0029]
Since the granulated product H from the granulator 5 is baked and volatilized by the calciner 6, the lead (Pb) content of heavy metals, especially the lead (Pb) content of the Ministry of the Environment “Soil content risk assessment study group” ", And the concentration of dioxins can be reduced to 40 pg / g or less, which is the standard for agricultural land in Germany.
Since the processed material K from the quenching device 9 is aged by the aging device 10, elution of lead (Pb), especially heavy metals, can be reduced to 0.01 mg / l or less which is the soil environment standard.
Therefore, according to the incineration residue treatment method and apparatus of the present invention, it can be provided at a low cost while having the same safety as that of molten slag.
[0031]
【The invention's effect】
As described above, according to the present invention, the following excellent effects can be obtained.
(1) A chlorinating agent is added to the incineration residue, and it is fired by the combustion exhaust gas from the incinerator to volatilize the chlorination. Therefore, the incineration residue is detoxified with high safety and low cost for effective use. Can do.
(2) When removing the coarse substances and metals in the incineration residue and crushing them and adding a chlorinating agent to granulate, the coarse substances and metals can be recovered and used for firing. Thus, the volatilization of chloride is promoted, and the content of heavy metals and the concentration of dioxins in the incineration residue can be reduced efficiently.
(3) When the combustion exhaust gas in the upper part of the post-combustion stoker of the incinerator is used for firing by raising the temperature to the temperature required for firing, and the exhaust gas after firing is guided to the boiler, By using a part, the burning energy can be reduced, and the calorific value of the exhaust gas after firing can be recovered with a boiler.
(4) When the baked product is aged after being rapidly cooled, the elution amount of heavy metals can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an incineration residue treatment apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Incineration residue processing apparatus, 2 ... Incinerator, 3 ... Boiler, 4 ... Pretreatment apparatus, 5 ... Granulation apparatus, 6 ... Firing apparatus, 7 ... Auxiliary combustion apparatus, 8 ... Exhaust gas recirculation apparatus, 9 ... Quenching apparatus, 10 DESCRIPTION OF SYMBOLS ... Aging apparatus, 11 ... Waste supply apparatus, 12 ... Dry stoker, 13 ... Combustion stoker, 14 ... Post combustion stoker, 15 ... Incineration residue discharge port, 16 ... Secondary combustion chamber, 17 ... Feed feeder, 18 ... Kiln drum , 19 ... Inlet hood, 20 ... Outlet hood, 21 ... Communication path, 22 ... Recirculation path, 23 ... Heat exchanger, 24 ... Blower , A ... Waste, B ... Combustion exhaust gas, C ... Incineration residue, D ... Coarse Product, E ... metals, F ... pre-treatment product, G ... chlorinating agent, H ... granulated product, I ... exhaust gas, J ... fired product, K ... treated product.

Claims (1)

A stoker incinerator for incinerating wastes, a boiler for generating steam depending on the combustion exhaust gas from the stoker incinerator, a processing unit prior to the removal of crude product and metals from incineration residue from stoker incinerator , A granulator for pulverizing the pre-treated product from the pre-treatment device and adding a chlorinating agent, a firing device for firing and granulating the granulated product from the granulation device, and a stoker-type incinerator An auxiliary combustion device that raises the combustion exhaust gas at the top of the post-combustion stoker to a temperature required for firing and supplies it to the firing device, an exhaust gas recirculation device that guides the exhaust gas from the firing device to the secondary combustion chamber of the stoker-type incinerator , An incineration residue treatment apparatus for a stoker-type incinerator characterized by comprising a quenching device for rapidly cooling a fired product from a firing device and an aging device for aging the treated product from the quenching device.

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