JP2526350B2 - Incineration ash treatment method and treatment device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incineration ash processing method and processing apparatus, and more particularly to a waste incineration ash (hereinafter simply referred to as incineration ash) incinerated from municipal waste or industrial waste. The present invention relates to an incineration ash treatment method and treatment apparatus for reducing harmful organic chlorine compounds.

[0002]

2. Description of the Prior Art Organochlorine compounds harmful to the human body, particularly aromatic compounds, such as highly toxic aromatic chlorine compounds such as PCDD (polychlorinated dibenzodioxin) and PCDF (polychlorinated dibenzofuran) , As a by-product of agricultural chemicals or as a secondary product of waste incineration, it is known to pollute the environment (K. Olie).
et al, Chemosphere, 6 , 455 (1
977), and T.W. Wakimoto et al,
Environmental Health Persp
ectives, 59 , 159 (1985)).

The present inventors have conducted various studies in order to reduce the organic chlorine compounds emitted from the refuse incineration facility, and as a result, have conducted an electric dust collector (E) attached to the refuse incineration facility.
It was found that the organic chlorinated compounds such as PCDD and PCDF may be mixed in the incineration ash discharged from P) and other dust removing devices. PCDD for incineration ash
When the incinerated ash containing PCD, PCDF, etc. is used for landfill, for example, it may flow back to the human body, animals and plants via leachate, etc., and there is a risk of adverse effects.

As a device for reducing the organic chlorine compounds in such incineration ash, for example, a thin layer moving external heating type heat treatment device, a paddle stirring external heating type heat treatment device,
Externally and directly heated single cylinder type rotary kilns and the like are known. FIG. 14 is an explanatory diagram of a thin-layer moving external heating type ash processing apparatus. This device is equipped with an inlet 52 for incineration ash B.
And an ash processing apparatus body 51 having a discharge port 53 for processing ash
And an introduction section screw 54 and a discharge section screw 55 arranged on the central axis in the longitudinal direction of the apparatus main body 51.
The incineration introduced from the incineration ash charging port 52 is mainly composed of a rotating shaft 56 having a rotating shaft 56, a stirring blade 57 attached to the rotating shaft 56, and a band heater 58 for heating the apparatus main body 51 from the outside. The ash B is moved toward the outlet 53 of the treated ash by the action of the screw 54 and the stirring blade 57 by the rotation of the rotating shaft 56, and is heated to, for example, 400 ° C. by the band heater 58 during the movement, and the incineration is performed. Ash B
Organic chlorine compounds such as danioxin contained in are decomposed.

[0005]

However, the above-mentioned conventional techniques can reduce harmful organic chlorine compounds contained in incineration ash, but in terms of reliability of machine equipment performance and treatment efficiency. In addition, it is difficult to say enough, and there are the following drawbacks. 1. Inside the main body of the processing equipment installed horizontally, a rotating shaft is supported, and a screw or paddle (stirring feed blade) is attached to the rotating shaft to perform stirring, mixing and transfer. The object filled between the blades of the rotating blades (screws or paddles) is heated and causes adhesion, and because there is no stirring space, the mixing properties are very poor. As if to form a heat insulating layer, it will significantly hinder external heating and heat transfer. Therefore, it takes a long time and a very high temperature to raise the temperature of the ash to be treated to the required temperature. Therefore, the ash to be treated filled between the apparatus main body casing and the rotary vanes becomes difficult to be heated uniformly, causes uneven heating, and is extremely unstable in thermal decomposition. 2. In the process of heat treatment of the ash to be treated in the treatment equipment, the separation from the heat-decomposed gas is insufficient or not considered at all. In the meantime, there is a possibility of recombination, resulting in a decrease in efficiency and instability of effect. 3. In order to improve the heat transfer effect, the band heater is directly attached to the main body casing.Therefore, there are restrictions such as the watt density and the heater installation area resulting from the heater characteristics. Is difficult to design. 4. In addition, most of the prior art device structures are of the one-cylinder type, and in the case of this type, there is no choice but to be markedly uneconomical design when the scale of the device is increased as the processing capacity increases. For example, if the inner moving speed and the residence time of the ash to be treated are kept constant and the amount of treatment is to be increased by a factor of 2, the cross-sectional area should be twice as large. Since it is not doubled (√2 times), the heat transfer area required for heating becomes insufficient. Therefore, the diameter of the device must be doubled, resulting in a quadruple cross-sectional area.

The object of the present invention is to solve the above-mentioned problems of the prior art, to secure a wide heat transfer area, to have high thermal efficiency, and to efficiently decompose organic chlorine compounds such as dioxins. It is to provide a processing method and a processing apparatus.

[0007]

In order to achieve the above object, the first invention of the present application is to provide a cylindrical heating furnace, and a plurality of heating pipes penetrating in the heating furnace in the axial direction. Stirring, mixing and adhering matter removing means provided inside the heating pipe, a drive device for revolving and rotating the heating pipe, a raw material introducing device for introducing incineration ash into the heating pipe, and heating The present invention relates to an incinerator ash treatment apparatus comprising: an incinerated ash outlet for separating treated incinerated ash from a decomposed gas and discharging the decomposed gas; and a decomposed gas extracting means for extracting the decomposed gas toward an outlet of the incinerated ash.

The second invention of the present application is to introduce incineration ash into a plurality of heating pipes which are provided penetrating in an axial direction in a cylindrical heating furnace, and rotate and revolve the heating pipes respectively, and, if necessary, While removing the deposits on the inner wall of the heating pipe, heat it to 350 ° C or higher to decompose the organic chlorine compounds contained in the incineration ash,
The present invention relates to a method for treating incinerated ash, which is characterized in that decomposed gas is extracted toward the outlet of the incinerated ash.

[0009]

By providing means for stirring, mixing and removing deposits of incinerated ash in a plurality of heating pipes, the ash to be treated is efficiently agitated and mixed, and the heat insulating layer formed by the ash to be treated inhibits heating and heat transfer. Since the formation is suppressed and heating is performed with high thermal efficiency, the treatment time is shortened, and the decomposition of the organic chlorine compound contained in the incinerated ash is efficiently promoted. In addition, since the heating pipe has a simple structure with no mechanically moving parts, it is possible to heat at a high temperature of 1000 ° C or higher with an electric heater, a combustion burner, etc. as a heating means. Unlike a screw, there is no restriction on the maximum heating temperature due to mechanical characteristics, and the incineration ash can be heated to a higher temperature, so the processing time is further shortened.

Further, by forming the heating tube as a plurality of tubes that revolve and rotate, it is possible to secure a wide heat transfer area with respect to the processing amount, the apparatus can be made compact, the heat transfer efficiency can be improved, and the processing cost can be improved. Can be significantly reduced. Further, the decomposition gas extraction means for extracting the decomposition gas from the heat-treated high-temperature treated ash in the direction of the outlet is provided to separate the decomposed gas from the treated ash, thereby lowering the temperature of the decomposed gas and recombining with the treated ash. Is prevented, the regeneration of the organic chlorine compound is prevented.

In the present invention, the heating tube is a tube body that rotates and revolves so as to penetrate through the heating furnace in the horizontal direction, and is usually composed of 2 to 8 cylinders or polygonal cylinders. Inside the heating tube, stirring, mixing and transfer means for promoting stirring of the ash to be treated are provided, and examples of these means include a continuous or discontinuous lifter provided on the inner wall surface of the heating tube. , Ribbon screws, short link chains, etc. Further, since these are provided in close contact with the heating pipe, they can also play the role of efficiently transmitting the heat from the outer surface of the heating pipe to the incineration ash inside. As the transfer means, the heating tube itself may be inclined from the inlet side to the outlet side and transferred by gravity, or a stirring and mixing means such as a ribbon screw may be provided with a propulsive force.

In the present invention, the adhering matter removing means includes:
Continuing with the rotating heating tube, for example, by a known external hammering means provided on the shaft outside the device, or by a short link chain or the like provided inside the heating tube as a stirring / mixing / heat transfer means. It is an internal hammering means for internal hammering, and it is possible to eliminate uneven heating caused by internal deposition of incineration ash and instability of decomposition effect caused by irregular peeling. By providing such stirring / mixing / transfer means and deposit removing means, it is possible to stir, mix, and convey the ash to be treated without using special mechanical power inside the heating tube.

In the present invention, the heating temperature of incineration ash is 35.
The temperature is 0 ° C or higher, preferably 400 to 550 ° C. 350
If the temperature is lower than ° C, the decomposition of the organic chlorine compound will be insufficient.
In the present invention, examples of the heating means provided in the heating furnace include a combustion burner and an electric heater.
When using a combustion burner as a heating source, the flow path of hot air generated in the heating furnace inside the heating furnace is generated by combustion of the burner and flows through the heating furnace toward the exhaust pipe while heating the heating tube in a zigzag manner. It is preferable to provide a rectifying plate for partitioning into. This not only increases the heat transfer area on the surface of the heating tube, but also lengthens the contact time between the hot air and the heating tube, so that the ash to be treated in the heating tube is efficiently heated. On the other hand, the heat transfer heater is arranged so as to be embedded in the furnace wall of the heating furnace, for example.

In the incineration ash after the heat treatment, in order to prevent recombination with a part of the decomposition gas, the heat decomposition gas and the treated ash can be separated and discharged, and can be rapidly cooled to 250 ° C. or lower. Preferably, in the present invention, as decomposition gas extraction means, for example, decomposition gas in the outlet direction of the treated ash,
A suction device that separates from the treated ash and forcibly withdraws can be used. On the other hand, as the cooling means, for example, a cooling device provided in the latter stage of the heating tube, for example, using water, air, or the like, a known cooling device provided after the discharge port of the object to be treated, or the like can be cited.

[0015]

EXAMPLES Next, the present invention will be described in more detail by way of examples. 1 is an explanatory view of an incineration ash treatment apparatus showing one embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG.
3 is a partially cutaway view showing a main part of FIG. 1, and FIG. 4 is a sectional view taken along line VI-VI of FIG.

In FIG. 1, this apparatus comprises a raw material charging device 6 for charging the incinerated ash A, a plurality of heating pipes 1 through which the charged incinerated ash A flows and moves, and heating for integrally heating the heating pipe 1. A furnace 2 and a combustion chamber 3 provided at the bottom of the heating furnace 2,
A combustion burner 4 provided in the combustion chamber 3, a hood 8 on the inlet side of the heating pipe 1, an hood 9 on the outlet side of the heating pipe 1, an exhaust gas outlet 10 through which decomposed gas is discharged, and the combustion. It is mainly composed of a straightening vane 7 that divides the flow path of the hot air, which is generated by the combustion of the burner 4 and flows through the heating furnace 2 and flows out from the exhaust stack 5, into zigzags. Multiple heating tubes 1
2 are concentrically arranged around a central axis in the longitudinal direction of the apparatus, and are configured to revolve around the central axis while rotating by a driving device (not shown). 3 and 4, the heating tube 1
A lifter 12 is provided inside the heating tube 1 as a means for mixing and stirring the ash to be treated. The heating pipe 1 is arranged with a gradient of, for example, 6 ° so that the horizontal level on the outlet side is lower than that on the inlet side.

In such a structure, the raw material charging machine 6,
For example, the incineration ash A charged from the screw feeder through the inlet hood 8 flows into the heating pipe 1 through a spoon-shaped saucer (not shown) provided at the inlet of the revolving heating pipe 1, and the heating pipe 1 It moves toward the outlet hood 9 along the inclination gradient of 1. At this time, the incinerated ash A is agitated and mixed by the action of the lifter 12 which rotates with the rotation of the heating tube 1, and the inner wall of the tube is beaten by an external hammering means (not shown) arranged on the shaft outside the apparatus. Of the organic matter contained in the incinerated ash A, which is heated to, for example, about 600 ° C. by the hot air that is generated by the combustion of the combustion burner 4 and that flows through the zigzag flow path that is divided by the straightening vanes 7 while being prevented from adhering to the ash A. Chlorine compounds decompose. The generated decomposition gas is separated from the incineration ash A, flows out from the exhaust gas outlet 10, and is introduced into, for example, the upstream of the dust collector of the waste incinerator outlet exhaust gas treatment facility for processing. On the other hand, the incineration ash from which organic chlorine compounds such as dioxins have been removed is separated from the exhaust gas, flows out from the outlet hood 9, and is cooled to, for example, 200 ° C. or lower by the cooling device 11 in the subsequent stage, if necessary, Discarded outside the system.

According to this embodiment, since the lifter 12 is provided in the heating pipe 1 as a means for promoting the stirring and mixing of the incineration ash, the incineration ash can be uniformly heated. Further, since the heating tube 1 is composed of a plurality of tubes, a large heat transfer area can be secured and heat transfer efficiency is improved, so that the processing time can be shortened. Furthermore, since the combustion burner 4 is used as a heating source, there is no restriction caused by mechanical characteristics, and since the incineration ash can be heated to, for example, about 800 ° C., the organic chlorine compound can be completely decomposed. . Further, the decomposition product gas is discharged through the outlet chute 9
In the above, since it is separated from the treated ash at a high temperature, it is possible to prevent the regeneration of dioxin and the like due to the re-reaction. Furthermore, since the heating pipe 1 is completely separated from the outside air, the oxygen concentration in the heating pipe can be adjusted to, for example, 1% or less, and the decomposition of harmful chlorine compounds is promoted.

In the present embodiment, as the combustion burner 4, for example, a burner which burns liquid or gas fuel is used, but instead of this, a high temperature gas generated by an electric heater or another device may be introduced. Further, as a cooling device for cooling the incineration ash after the heat treatment from which the organic chlorine compound is removed, for example, a paddle / jacket water cooling type cooler is used, but other known cooling devices can also be used.

In the present embodiment, the lifter 12 provided in the heating pipe 1 may be continuous or discontinuous. Further, the stirring / mixing means provided in the heating pipe is not limited to the lifter and may have another configuration. 5 to 13 are explanatory views showing an example of the stirring / mixing means used in the present embodiment.

5 (a) and 5 (b) are a partially cutaway view and a sectional view showing a state in which a ribbon screw 13 is installed in a heating tube as a stirring / mixing means. According to this stirring / mixing means, stirring and mixing of the incineration ash moving in the heating pipe can be promoted and the feeding can be made smooth. Ribbon screw 13
The heat is transferred to the incineration ash through the heat transfer, and the heat transfer efficiency is improved. The ribbon screw 13 can be provided continuously or discontinuously, and by using a discontinuous paddle screw, the stirring effect can be further improved.

FIGS. 6 (a) and 6 (b) are an explanatory view and a cross-sectional view showing a state in which a short link chain 14 is provided in a heating pipe as a stirring / mixing means, respectively. The short link chains 14 are arranged in a crossing so as to connect the upper part on the inlet side and the lower part on the outlet side of the heating pipe, and the lower part on the inlet side and the upper part on the outlet side, respectively, to promote stirring and mixing and to heat the heating pipe 1. It is possible to prevent ash from adhering to the inner wall surface of the.

7 (a) and 7 (b), discontinuous chain attachment plates / lifters 15 are provided in the heating pipe, respectively, with their pitches being sequentially shifted, and the lengths of the chain attachment plates / lifters 15 are increased. It is explanatory drawing which shows the state which attached the chain 16 slightly shorter than the inner diameter of the pipe 1, and its sectional drawing. Two to six chain attachment plates / lifters 15 and chains 16 are provided on the circumference of the heating tube. This stirring / mixing means also promotes the stirring and mixing of the incinerated ash and improves the heat transfer efficiency.

FIGS. 8A, 8B and 8C are explanatory views in which a large number of heat transfer studs 17 are provided in the heating pipe,
It is a sectional view and a partially enlarged view. The heat transfer stud 17 is slightly shorter than 1/2 of the inner diameter of the heating tube, for example, 4 to 1
It is composed of a 0φ round bar. According to this stirring / mixing means, stirring and mixing of ash can be promoted, and the heat transfer area on the inner surface can be increased by about 1.5 to 2 times as compared with the outer surface.
Heat transfer efficiency is improved. The heat transfer stud may be a round bar, for example, a square bar or a hexagonal bar.

9A and 9B, the heat transfer stud of FIG. 8 is made longer to reach the opposite wall surface,
FIG. 3 is an explanatory view and a cross-sectional view showing a state in which a heat transfer stud 18 is passed through the heat transfer stud and a moving ring 19 is inserted therein. By this means, it is possible to promote the mixing of ash and prevent the ash from adhering to the wall surface. 10 (a), (b)
FIG. 3 is an explanatory view and a cross-sectional view showing a state in which a lifter 20 is provided on the inner wall of the heating tube 1 and a plurality of round bars 21 are loaded. According to this stirring / mixing means, it is possible to promote the mixing of ash and improve the heat transfer effect, and prevent ash from adhering to the inner wall of the heating pipe 1. In this embodiment, balls may be loaded instead of the round bar 21.

FIGS. 11 (a) and 11 (b) are an explanatory view and a cross-sectional view showing a state where the heating pipe 1 is filled with a wire net 22 in a scrubber shape. The wire net 22 rotates in synchronization with the heating pipe 1. According to this mixing means, the mixing of ash is promoted, and heat is transferred through the wire net 22, so that the heat transfer efficiency is improved. 12 (a) and 12 (b) are an explanatory view and a cross-sectional view showing a state in which a propeller-shaped battle 23 spread at 180 ° is attached to the central axis 24 of the heating tube. According to this stirring / mixing means, the rotation of the heating pipe promotes the stirring of the ash, and at the same time, the adhesion of the ash to the inner wall can be prevented. In this embodiment, the propeller-shaped battle 23 may be fixed or rotatable.

FIGS. 13A and 13B are an explanatory view and a sectional view showing a state in which the baffle ring 25 is inserted into the heating tube 1 to divide the inside into a plurality of parts. According to this stirring / mixing means, it is possible to prevent short-circuiting of incinerated ash and promote stirring and mixing. Mixing can be further promoted by passing the crosspiece 26 through the baffle ring 25. Further, for example, a steel ball of 5 to 10 mmφ can be loaded. The baffle ring 25,
The crosspiece 26 and the steel ball 27 may be used individually,
Also, they can be arbitrarily combined.

Next, specific examples of the present invention will be described.
The inner diameter of the heating tube 1 is 150φ and the length is 2000 mm,
Using the apparatus having the configuration shown in FIG. 1 with four heating tubes, the municipal waste incineration facility is operated under the conditions of 100 kg / h of raw material input, 600 ° C. in heating furnace temperature, 450 ° C. in heating temperature, and 5 minutes in heating time. When the EP collected ash of No. 2 was treated, PCDD in the ash was changed from 340 ng / g to 2 ng / g, and the removal rate η was 99.4%.

[0029]

According to the first invention of the present application, the heating pipe is arranged so as to penetrate through the heating furnace, and the heating pipe is provided in plural and the incineration ash stirring means is provided therein. Since the heat transfer area is widened and the heat transfer efficiency is improved, the organic chlorine compound in the incineration ash can be efficiently decomposed, and the treatment time can be greatly shortened.

According to the second invention of the present application, the incineration ash is introduced into a plurality of heating pipes and heated to 350 ° C. or higher while stirring, mixing and removing deposits adhering to the inner wall as necessary, By extracting the generated decomposition gas toward the outlet of the treated ash, it is possible to efficiently decompose the organic chlorine compound in the incineration ash and prevent its regeneration.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an incineration ash processing apparatus showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a partially cutaway view showing a main part of FIG.

FIG. 4 is a sectional view taken along line IV-IV of FIG.

[Fig. 5]

[FIG. 6]

[FIG. 7]

FIG. 8

FIG. 9

FIG. 10:

FIG. 11:

FIG.

FIG. 13 is an explanatory diagram showing a main part of each embodiment of the present invention.

FIG. 14 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heating pipe, 2 ... Heating furnace, 3 ... Combustion chamber, 4 ... Combustion burner, 5 ... Exhaust pipe, 6 ... Raw material charging machine, 7 ... Straightening plate, 8 ... Inlet hood, 9 ... Outlet hood, 10 ... Exhaust gas outlet , 11 ...
Cooling device, 12 ... lifter, 13 ... ribbon screw,
14 ... Short link chain, 15 ... Chain mounting plate / lifter, 16 ... Chain, 17 ... Heat transfer stud,
18 ... Through heat transfer stud, 19 ... Moving ring, 20 ... Lifter, 21 ... Round bar, 22 ... Wire mesh, 23 ... Propeller-like battle, 25 ... Baffle ring, 26 ... Crosspiece, 27 ... Steel ball.

Claims (2)

(57) [Claims] 1. A cylindrical heating furnace, a plurality of heating pipes penetrating in the heating furnace in an axial direction, and stirring, mixing, and transferring of an object to be treated provided inside the heating pipe. And adhering matter removing means, a drive device for revolving and rotating the heating pipe, a raw material introducing device for introducing incineration ash to the heating pipe, and an incineration ash discharge for separating the heat-treated incineration ash from decomposed gas and discharging. An incineration ash treatment apparatus comprising an outlet and a decomposition gas extraction means for extracting the decomposition gas in the direction of the incineration ash outlet. 2. An incinerator ash is introduced into a plurality of heating pipes penetrating in the axial direction in a cylindrical heating furnace, and the heating pipes are rotated and revolved while being transferred to the outlet side, if necessary. According to the incineration ash treatment, it is heated to 350 ° C or higher to decompose organic chlorine compounds contained in the incineration ash and remove the decomposed gas toward the outlet of the incineration ash while removing the deposits on the inner wall of the heating pipe. Method.