JP2001208306A - Waste melting facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a waste melting facility having a gas cooling device 13 which cools the exhaust gas from a melting furnace 10 that melts an incombustible waste, and a waste gas filtering device 16 which removes dust from the cooled waste gas in a flue 11 to recover valuable metals in such a state as to be separated from dioxins while preventing the discharge of the dioxins from the system to the outside. SOLUTION: The waste melting facility is provided with a revolving chamber 1 formed in a cylindrical shape with a bunker section 3 having an internal wall section 2 formed in an inverted conical surface-like shape on its bottom side, a waste gas leading-in pipe 4 connected to the internal wall 2 in the tangential direction, and a gas leading-out pipe 6 which leads a led-in waste gas upward from the revolving chamber 1 along the axial center of the chamber 1. In the chamber 1, in addition, a cyclone type reactor 14 provided with a caustic liquid supplying mechanism 5 which sprays a caustic liquid in the chamber 1 and a molten fly ash recovering mechanism 9 which recovers molten fly ash recovered in the chamber 1 and takes out of the system is provided on the upstream side of the waste gas filtering device 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste melting treatment facility, and more particularly, to a melting treatment furnace for melting non-combustible waste and recovering it as molten slag, and a gas for cooling exhaust gas from the melting treatment furnace. The present invention relates to a waste melting treatment facility in which a cooling device and an exhaust gas filtering device for collecting dust accompanying the exhaust gas cooled by the gas cooling device are sequentially provided in a flue that guides exhaust gas from the melting furnace to a chimney. .

[0002]

2. Description of the Related Art Conventionally, in a waste melting treatment facility,
As shown in FIG. 3, a melting treatment furnace 10 for melting non-combustible waste and collecting it as molten slag;
A gas cooling device 13 for cooling the exhaust gas from zero and an exhaust gas filtering device 16 for collecting dust accompanying the exhaust gas cooled by the gas cooling device 13 guide the exhaust gas from the melting furnace 10 to a chimney 19. It is provided in the flue 11 in order. In the illustrated example, the melting furnace 10 is constituted by a surface melting furnace 10A, and after the combustible gas generated in the main chamber 10b is secondarily burned in the secondary chamber 10c, the guide path 10 is formed.
d to the post-combustion chamber 10e.
And complete combustion by supplying secondary air. Then, the exhaust gas from the post-combustion chamber 10 e is introduced into the flue 11 that guides the exhaust gas to the gas cooling device 13.
An air preheater 12 for preheating the primary air to the air and the secondary air to the post-combustion chamber 10e is disposed to recover the sensible heat held by the exhaust gas. The gas cooling device 13 is a cooling tower 1
A water-cooled type equipped with a water spray mechanism 13b for spraying water into 3a is used, and exhaust gas cooled to 130 to 150 ° C is sent to the exhaust gas filtering device 16. The exhaust gas from which the dust has been removed by the exhaust gas filtering device 16 is rendered harmless by an exhaust gas treatment device 17 and then sent out to a chimney 19 by an induction blower 18.

[0003]

In the above-mentioned conventional waste melting treatment equipment, the temperature of the exhaust gas at the inlet of the gas cooling device 13 is about 600 ° C., and the dioxins are recycled during the cooling process in the gas cooling device 13. It is easy to synthesize. Therefore, activated carbon is supplied in the flue 11 reaching the exhaust gas filtering device 16 to adsorb and remove the generated dioxins. The dioxins are removed together with the molten fly ash recovered by the exhaust gas filtering device 16. The adsorbed activated carbon will be collected. The molten fly ash contains or accompanies a valuable metal, but in order to recover this valuable metal from the molten fly ash collected in the conventional waste melting treatment facility, dioxins must be removed at the same time. Have the problem of having to do so. This is not preferable because it complicates the valuable metal recovery process for recovering the valuable metal. Therefore, the waste melting treatment equipment of the present invention solves the above problems, prevents the release of dioxins outside the system, and enables recovery of valuable metals in a state separated from dioxins. The purpose is to:

[0004]

[Means for Solving the Problems] The waste melting treatment equipment according to the present invention separates molten fly ash together with chlorine content from the exhaust gas after cooling the exhaust gas and before removing it with an exhaust gas filtration device. It has a feature in points, and has a configuration having the following features, respectively.

[First characteristic configuration] A first characteristic configuration of a waste melting treatment facility according to the present invention for the above purpose is a bunker having an inner wall portion formed in an inverted conical shape as described in claim 1. A swirl chamber, which is provided in the lower part, and is formed in a cylindrical shape and swirls the exhaust gas to be introduced therein, an exhaust gas inlet pipe connected tangentially to the inner wall of the swirl chamber, and an exhaust gas inlet pipe. A gas outlet pipe that guides the exhaust gas that has been introduced and swirled down from the swirl chamber along the axis of the swirl chamber, and connects the exhaust gas inlet pipe to an upstream flue; A discharge pipe for discharging exhaust gas discharged from the discharge pipe is connected to a flue on the downstream side, and a caustic supply mechanism for spraying caustic liquid into the swirl chamber and a molten fly ash collected in the swirl chamber are collected. Ash recovery mechanism That a cyclone reactor in a point that is provided on the upstream side of the flue of the exhaust gas filtration apparatus.

[Second feature configuration] A second feature configuration of the waste melting treatment equipment according to the present invention for the above purpose is as described in claim 2, wherein the cyclone type reactor in the first feature configuration is provided. An activated carbon supply mechanism for supplying activated carbon particles to a flue between an exhaust gas filtration device and a collected dust circulation path for circulating dust collected by the exhaust gas filtration device as a material to be processed in a melting furnace is provided. At one point.

[Third characteristic configuration] A third characteristic configuration of the waste melting treatment facility according to the present invention for the above purpose is as described in claim 3, wherein the activated carbon supply mechanism in the second characteristic configuration is The present invention is characterized in that a carbonaceous pyrolysis solid discharged from a pyrolysis furnace for pyrolyzing waste as activated carbon particles is supplied.

[Fourth feature configuration] A fourth feature configuration of the waste melting treatment facility according to the present invention for the above purpose is as described in claim 4, wherein the gas cooling in the second or third feature configuration is performed. The gas cooling device is provided with a dust discharge mechanism for collecting dust settled in the device and discharging the dust to a collected dust circulation path.

[Effects of each feature] According to the above features, release of dioxins outside the system can be prevented.
Further, valuable metals can be recovered in a state separated from dioxins.

[Effects of the first characteristic configuration] That is, according to the first characteristic configuration, the molten fly ash in the exhaust gas is captured by the cyclone-type reactor together with the chlorine solidified by reacting with the caustic liquid. Since it collects, further generation of dioxins on the downstream side can be prevented. Therefore, even if gaseous dioxins are generated in the exhaust gas, if an adsorbent for the dioxins such as activated carbon is supplied to the flue to the exhaust gas filtration device on the downstream side, the downstream of the exhaust gas filtration device. The dioxins can be prevented from flowing out to the side.

According to the second feature configuration, while exhibiting the function and effect of the first feature configuration, an activated carbon supply mechanism is provided between the cyclone-type reactor and the exhaust gas filtering device. By supplying the activated carbon particles to the exhaust gas, dioxins in the exhaust gas are adsorbed on the activated carbon particles, and the dioxins are collected together with the activated carbon particles by the exhaust gas filtration device. Here, if the dioxins adsorbed and collected on the activated carbon particles are circulated and supplied to the melting treatment furnace from the collection dust circulation path together with the collected fly ash, the dioxin on which the circulated and supplied activated carbon particles are adsorbed is obtained. The species are completely decomposed by the high temperature in the melting furnace. Therefore, discharge of dioxins out of the system can be prevented.

[Function and Effect of Third Characteristic Configuration] According to the above-mentioned third characteristic configuration, the thermal decomposition residue can be effectively used while exhibiting the function and effect of the above-mentioned second characteristic configuration. In other words, the pyrolysis residue after waste pyrolysis contains carbonaceous pyrolysis solids, which are activated carbons with high activity and adsorb dioxins. It is suitable to do. Therefore, if the carbonaceous pyrolysis solid discharged from the pyrolysis furnace is supplied to the activated carbon supply mechanism, it can be used as fresh and highly active activated carbon. In this way, while preventing the emission of dioxins outside the system, the combustible material is thermally decomposed, the pyrolysis residue is used as activated carbon, the pyrolysis residue is incinerated, and the incineration residue is also removed. It is possible to achieve an integrated incineration melting process that can be melted.

According to the fourth aspect, the dust containing dioxins generated in the gas cooling device is heated to a high temperature while exhibiting the effects of the second or third aspect. Will be able to re-decompose below. Therefore, emission of dioxins can be reliably suppressed. That is, in the gas cooling device, the exhaust gas is cooled by passing through a temperature range in which dioxins at 500 to 300 ° C. are easily resynthesized, and the exhaust gas contains chlorine mainly composed of hydrochloric acid, Dioxins are easily produced due to the presence of carbon components such as carbon monoxide in the exhaust gas.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an embodiment of the waste melting treatment equipment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a waste melting treatment facility according to the present invention, and FIG. 2 is a plan sectional view of a cyclone type reactor in the waste melting treatment facility shown in FIG.
Note that the same elements as those described in the related art and elements having the same functions are denoted by the same reference numerals as in FIG. 3 and a part of the detailed description is omitted.

As shown in FIG. 1, the waste melting treatment facility includes a melting treatment furnace 10 for melting non-combustible waste and recovering it as molten slag, and a sensible heat of exhaust gas from the melting treatment furnace 10. An air preheater 12 to be recovered, a gas cooling device 13 for further cooling the exhaust gas from the exhaust gas, an exhaust gas filtering device 16 for recovering dust accompanying the exhaust gas cooled by the gas cooling device 13, and an exhaust gas treatment device 17 A flue 1 for guiding exhaust gas from the melting furnace 10 to a chimney 19
1 in order. The exhaust gas from the exhaust gas filtering device 16 is rendered harmless by the exhaust gas processing device 17 and then sent out to a chimney 19 by an induced blower 18. And
In the flue 11 between the gas cooling device 13 and the exhaust gas filtering device 16, chlorine such as hydrochloric acid in the exhaust gas from the gas cooling device 13 is collected, and at the same time, in the exhaust gas from the gas cooling device 13. A cyclone type reactor 14 for collecting fly ash is provided. As shown in the figure, the melting furnace 10 melts an object to be processed in a main chamber 10b.
It comprises a surface melting furnace 10A configured to completely burn the combustion gas from 0b in the post-combustion chamber 10e. Further, between the exhaust gas filtration device 16 and the treatment object charging section 10a of the melting treatment furnace 10, the dust collected by the exhaust gas filtration device 16 is circulated and supplied to the melting treatment furnace 10 as a treatment object. A dust circulation path 21 is provided. The dioxins are collected by the exhaust gas filtering device 16 and circulated and supplied to the melting furnace 10 to re-decompose the collected dioxins as described later. The gas cooling device 13 includes a water spray mechanism 1 for spraying water into the tower.
The gas cooling device 13 is provided with a dust discharging mechanism 13c that collects dust settled in the gas cooling device 13 and discharges the collected dust to the collected dust circulation path 21. The dust discharging mechanism 13c is configured to discharge the dust while keeping the cooling tower 13a airtight to the outside. In the example shown,
A mechanism combining a circle feeder and a rotary valve is adopted.

As shown in FIG. 2, for example, the cyclone type reactor 14 is formed in a cylindrical shape and has a swirl chamber 1 for swirling the exhaust gas to be introduced therein, and the exhaust gas swirling and descending in the swirl chamber 1. And a discharge unit 7 that discharges exhaust gas from the gas discharge pipe 6 to the downstream side. The swirling chamber 1 has a bunker portion 3 having an inner wall portion 2 formed in an inverted conical shape at a lower portion, and an exhaust gas introducing pipe 4 connected to a tangential direction of an inner wall of the swirling chamber 1 and an exhaust gas introducing pipe thereof. Introduced from 4,
A gas discharge pipe 6 for guiding the exhaust gas swirled down from the swirl chamber 1 upward along the axis of the swirl chamber 1,
The exhaust gas introduction pipe 4 is connected to the flue 11 on the upstream side. Further, an exhaust pipe 8 for discharging the exhaust gas led to the discharge section 7 to the outside is connected to a flue 11 on the downstream side. Further, the swirl chamber 1 is provided with a caustic supply mechanism 5 for spraying and supplying a caustic liquid into the swirl chamber 1.
Is provided with a molten fly ash recovery mechanism 9 provided for recovering the molten fly ash collected in the swirling chamber 1 and taking it out of the system. The molten fly ash recovery mechanism 9 is constituted by a rotary valve as shown in the drawing, and is configured to take out the molten fly ash collected while keeping the swirling chamber 1 airtight to the outside. It is.

The flue gas from the post-combustion chamber 10e is discharged to a flue 11 at about 950 ° C., and the exhaust gas introduced into the air preheater 12 is converted into primary air to the main chamber 10b and the post-combustion chamber. Heating the secondary air to 10e to 600
℃, the gas cooling device 13 deprives the latent heat of vaporization of water from the water spray mechanism 13b to about 200 ° C.
And discharged to the flue 11 on the downstream side to reach the cyclone type reactor 14. A caustic liquid (for example, sodium hydroxide solution) is sprayed in the cyclone-type reactor 14, and the temperature of the exhaust gas from the cyclone-type reactor 14 is reduced to about 150 ° C. Therefore, in the exhaust gas cooling device 13, the exhaust gas is heated from about 600 ° C to about 2 ° C.
When the temperature is lowered to 00 ° C., dioxins containing a dioxin precursor are generated to some extent due to the presence of chlorine components such as hydrochloric acid in the exhaust gas. However, the solid components of the dioxins are discharged from the exhaust gas cooling device 13. And settled by the dust discharge mechanism 13c.
The fly ash discharged from the exhaust gas cooling device 13 does not contain dioxins as solid components (the gaseous dioxins are contained in the exhaust gas). This exhaust gas is introduced into the cyclone-type reactor 14 and a caustic solution is sprayed to remove chlorine, and at the same time, the reaction product is collected together with fly ash.
Re-synthesis of dioxins is not performed in the swirl chamber 1 and thereafter, so that re-synthesis of dioxins on the downstream side of the cyclone reactor 14 can be prevented. In addition, since the caustic liquid collected in the cyclone-type reactor 14 reacts with chlorine in the exhaust gas, solids and molten fly ash are collected without containing dioxins. Even if this is taken out of the system, the dioxins are not taken out together and can be directly used for the valuable metal recovery treatment. In the cyclone-type reactor 14, extremely fine molten fly ash is discharged from the discharge pipe 8 to the flue 11 on the downstream side together with the exhaust gas, and collected by the exhaust gas filtering device 16.

An activated carbon supply mechanism 15 for supplying activated carbon particles is provided in the flue 11 between the cyclone type reaction device 14 and the exhaust gas filtering device 16. The activated carbon supply mechanism 15 supplies a carbonaceous pyrolysis solid substance supply path 15 a for supplying the carbonaceous pyrolysis solid substance discharged from the pyrolysis furnace 20 for thermally decomposing waste as the activated carbon particles to the flue 11.
Is provided. In other words, this waste melting treatment equipment melts incineration residues such as incineration ash, and at the same time, pyrolyzes combustible wastes in the pyrolysis furnace 20 and then decomposes the pyrolysis residues in the melting furnace 10. In addition to incineration, the incineration residue is melted. The incineration residue carbonaceous pyrolysis solids are used as activated carbon particles and supplied to the flue 11 on the upstream side of the flue gas filtering device 16 to be contained in the flue gas in the flue 11. The dioxins are adsorbed and fixed to solid particles. The activated carbon supply mechanism 15 is provided with a filter cloth coating agent (Ca) for facilitating separation of collected dust from a filter cloth for filtering exhaust gas in the exhaust gas filtering device 16 on the downstream side.
A coating agent supply path 15b is also provided so as to simultaneously supply (OH) ₂ , diatomaceous earth, etc., so that dust collected by the filter cloth can be easily collected.

With the above configuration, in the above-mentioned waste melting treatment facility, even if dioxins are generated in the system, emission of dioxins can be prevented in the exhaust gas, and dioxin can be prevented. The collected fly ash, which has a very low content of metals, can be taken out to recover valuable metals containing almost no harmful impurities.

[Another Embodiment] Next, a part of another embodiment of the present invention not described in the above embodiment will be described.

<1> In the above embodiment, the air preheater 12 for recovering the sensible heat of the exhaust gas from the melting furnace 10 is provided with the flue 11 from the rear combustion chamber 10 e of the melting furnace 10. However, the air preheater 12 may be attached to the rear combustion chamber 10e of the melting furnace 10.

<2> In the above embodiment, an example was described in which the melting furnace 10 was constituted by a surface melting furnace, but the melting furnace 10 may be a different type of melting furnace. For example, a rotary melting furnace may be used,
A rotary kiln type melting processing furnace may be used.

<3> In the above embodiment, the example in which the exhaust gas introduction pipe 4 is connected to the swirl chamber 1 in the tangential direction of the inner wall of the cyclone type reactor 14 has been described. The introduction pipe 4 only needs to be arranged so that the exhaust gas introduced into the swirl chamber 1 is swirled in the swirl chamber 1. May be arranged so as to introduce.

<4> In the above embodiment, an example was described in which the molten fly ash recovery mechanism 9 was constituted by a rotary valve. However, the structure of the molten fly ash recovery mechanism 9 is arbitrary. In a state where the swirling chamber 1 is sealed to the outside,
Any known means can be used as long as it is a mechanism capable of taking out the molten fly ash collected in the swirling chamber 1 to the outside.

<5> In the above embodiment, an example was described in which the gas cooling device 13 was constituted by a water cooling tower that sprays water into the tower. For example, a gas cooling device of a system for supplying cooling air to dilute and cool exhaust gas may be used. Although dioxins may be generated in the gas cooling device 13, it is preferable to have a mechanism for collecting solid dioxins generated therein. And it is desirable that at least the outlet temperature is lower than the generation temperature of dioxins.

<6> In the above embodiment, the temperature of the exhaust gas at the outlet of each of the post-combustion chamber 10e, the air preheater 12, the gas cooling device 13, and the cyclone-type reactor 14 is shown. And differs depending on the configuration of the waste melting treatment facility. However, it is desirable that the inlet temperature of the cyclone type reactor 14 is lower than at least the generation temperature of dioxins. Under such temperature conditions, the cyclone-type reactor 1
Since no dioxins are generated in 4, the valuable metals in the fly ash can be recovered in the absence of dioxins as collected.

<7> In the above-described embodiment, an example in which the activated carbon supply mechanism 15 is provided in the flue 11 between the cyclone type reaction device 14 and the exhaust gas filtration device 16 has been described. 15 may be provided at another position, for example, the cyclone type reactor 1
The activated carbon particles may be supplied to the downstream side of the swirling chamber 1 in the inside of the swirl chamber 4.

<8> In the above embodiment, the activated carbon supply mechanism 15 is configured to supply the carbonaceous pyrolysis solids discharged from the pyrolysis furnace 20 for pyrolyzing waste as activated carbon particles. However, the activated carbon supply mechanism 15 may be configured to supply activated carbon particles obtained by other means.

<9> In the above embodiment, an example in which the air preheater 12 is provided in the flue 11 at the outlet of the melting furnace 10 has been described, but a waste heat boiler is provided before the air preheater 12. They may be arranged. In this case,
Instead of providing a gas cooling device independently, a water preheater for supplying water to the waste heat boiler may be arranged downstream of the air preheater 12 to cool exhaust gas.

<10> In the above-described embodiment, an example has been described in which the collected dust circulation path 21 for circulating the dust collected by the exhaust gas filtering device 16 as an object to be processed to the melting furnace 10 is provided. Without providing the collected dust circulation path 21, the dust may be supplied to the melting treatment furnace 10 by another transport means, or the dust collected by the exhaust gas filtration device 16 may be treated by another means outside the system. You may make it.

<11> In the above embodiment, an example in which the gas cooling device 13 is provided with a dust discharge mechanism 13 c that collects dust settled in the gas cooling device 13 and discharges the collected dust to the collected dust circulation path 21. However, the dust from the dust discharging mechanism 13c may be separately collected and processed without being discharged to the collected dust circulation path 21.

<12> In the above embodiment, the cyclone-type reactor 14 has been described as being constituted by the swirl chamber 1 and the discharge section 7, and the discharge section 7 has an enlarged space. Although an example is illustrated, the discharge pipe 8 may constitute the discharge section 7.

Incidentally, reference numerals are written in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing an example of a waste melting treatment facility according to the present invention.

FIG. 2 is a cross-sectional plan view showing an example of a cyclone type reactor according to the present invention.

FIG. 3 is a configuration explanatory view showing an example of a conventional waste melting treatment facility.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 swirl chamber 2 inner wall part 3 bunker part 4 exhaust gas introduction pipe 5 caustic supply mechanism 6 gas outlet pipe 8 discharge pipe 9 molten fly ash recovery mechanism 10 melting treatment furnace 11 flue 13 gas cooling device 13c dust discharge mechanism 14 cyclone type reaction device 15 Activated carbon supply mechanism 16 Exhaust gas filtration device 19 Chimney 20 Pyrolysis furnace

Claims (4)

[Claims] A melting furnace for melting non-combustible waste and collecting it as molten slag, and a gas cooling device for cooling exhaust gas from the melting furnace.
And an exhaust gas filtering device (16) for collecting dust accompanying the exhaust gas cooled by the gas cooling device (13), and a flue (19) for guiding the exhaust gas from the melting furnace (10) to a chimney (19). 11) A waste melting treatment facility provided in order in (11), which is provided with a bunker part (3) having an inner wall part (2) formed in an inverted conical shape at a lower part, and is formed into a cylindrical shape and introduced. Swirl chamber (1) for swirling the exhaust gas inside, exhaust gas introduction pipe (4) connected tangentially to the inner wall of the swirl chamber (1), and the exhaust gas introduced from the exhaust gas introduction pipe (4) and swirled down A gas outlet pipe (6) for guiding the exhaust gas upward from the swirl chamber (1) along the axis of the swirl chamber (1), and the exhaust gas inlet pipe (4) is connected to an upstream flue. (1
1) and a discharge pipe (8) for discharging exhaust gas discharged from the gas discharge pipe (6).
1) a caustic supply mechanism (5) for spraying caustic liquid into the swirl chamber (1), and a molten fly ash collected in the swirl chamber (1) to be collected and discharged outside the system. A cyclone-type reactor (1) having a molten fly ash recovery mechanism (9)
4) the flue (1) on the upstream side of the exhaust gas filtering device (16).
Waste melting facility installed in 1). 2. An activated carbon supply mechanism (15) for supplying activated carbon particles to a flue (11) between the cyclone type reactor (14) and the exhaust gas filtering device (16), and the exhaust gas filtering device (15). The waste melting treatment facility according to claim 1, further comprising a collected dust circulation path (21) for circulating the dust collected in (16) to the melting treatment furnace (10) as an object to be treated. 3. A pyrolysis furnace (2) for thermally decomposing waste as said activated carbon particles by using said activated carbon supply mechanism (15).
3. The waste melting treatment facility according to claim 2, wherein the facility is configured to supply the carbonaceous pyrolysis solid discharged from step (0). 4. The gas cooling device (13) is provided with a dust discharge mechanism (13c) for collecting dust settled in the gas cooling device (13) and discharging the collected dust to the collected dust circulation path (21). The waste melting treatment facility according to claim 2.