JP2000233112A - Waste gas treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove harmful components such as dioxins to the full extent by efficiently utilizing an adsorbent employed for a packed-layer adsorption- regeneration method at the time of adsorptive removal of harmful components such as dioxins of a waste gas. SOLUTION: This waste gas treatment apparatus comprises a dust collecting apparatus 2, a packed-layer 4 filled with a carbon-based adsorbent in the downstream side of the apparatus 2, a regeneration apparatus 6 for regenerating the adsorbent whose adsorption capability is deteriorated, and a separation apparatus 7 for separating a regenerated adsorbent, a powdered adsorbent, and dust. A blowing apparatus 9 to blow the powdered adsorbent containing dust to the inlet side of a duct of the dust collecting apparatus 2 is installed in the waste gas treatment apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating exhaust gas which is effective for removing harmful substances such as dioxin discharged from incineration equipment of municipal garbage and industrial waste, steel electric furnaces and steel sintering machines. It is.

[0002]

2. Description of the Related Art As a method of adsorbing exhaust gas containing harmful substances such as dioxin, there are an adsorbing technique using a packed bed and a blowing technique of a powder adsorbent. As an adsorption technique using a packed bed, as disclosed in Japanese Patent Application Laid-Open No. 7-763, an exhaust gas at 90 to 120 ° C. containing dioxins is sent to a cross-flow moving bed adsorption apparatus filled with activated carbon or activated coke. There is a method in which dioxins are removed, the activated carbon or activated coke used is heated and regenerated, and recycled. In addition, as an adsorbent injection technique, Japanese Patent Application Laid-Open
No. 19237, an adsorbent is supplied to the exhaust gas on the upstream side of the dust collector, and the adsorbent and dust are collected.
A method for supplying it to a combustor,
There is an exhaust gas treatment method as disclosed in Japanese Patent Publication No. 41, wherein the temperature of incinerated exhaust gas is reduced and dust is removed, and then an adsorbent is added and the adsorbent is collected by a bag filter.

[0003]

However, in the method of moving bed adsorption and recycling after use described in JP-A-7-763, a part of the adsorbent is powdered, and the powdered adsorbent is finely divided. The powdered adsorbent cannot be reused in the moving bed due to the particles, and the powdered adsorbent is sieved after regeneration, returned to an exhaust gas generation facility such as an incinerator, and incinerated.

In addition, in the blowing of the adsorbent disclosed in Japanese Patent Application Laid-Open No. 10-19237, the adsorbent is collected together with the dust, so that it is difficult to regenerate the adsorbent and the adsorbent cannot be reused. Further, in the case of Japanese Patent Application Laid-Open No. 8-2433331, in order to avoid the above-described problem, the adsorbent is collected after dust removal, regenerated, and reused. However, this method requires an extra bag filter for collecting the adsorbent after the ordinary dust remover.

[0005] Therefore, it cannot be said that any conventional method effectively utilizes an expensive adsorbent. Therefore, the present invention solves the above-mentioned problems of the prior art, and provides an exhaust gas treatment apparatus capable of efficiently using a sorbent used in a packed bed adsorption-regeneration method and highly removing harmful components such as dioxin. The purpose is to do.

[0006]

SUMMARY OF THE INVENTION In an exhaust gas treatment method using a packed bed adsorption-regeneration system using a carbon-based adsorbent, after heating and regeneration, the sieved powdered adsorbent is added to the granular material used in the packed bed. The inventors have found that they have a higher adsorptive power than the adsorbent, and have completed the present invention.

That is, the present invention provides a dust collector, a packed bed filled with a carbon-based adsorbent downstream thereof, and a regenerating apparatus for regenerating an adsorbent having reduced adsorption performance, and a separating apparatus for separating a regenerated adsorbent from a powdered adsorbent. The exhaust gas treatment device according to claim 1, further comprising a blowing device for blowing the powdered adsorbent into an inlet flue of the dust collector. Furthermore, the blown powdered adsorbent is collected by a dust collector,
The recovered adsorbent is charged into an exhaust gas generation facility, or charged into an ash melting furnace when the dust contains a large amount of ash such as silica or alumina. Activated carbon or activated coke is preferred as the carbon-based adsorbent of the present invention. The exhaust gas generation equipment refers to equipment that generates exhaust gas containing harmful substances such as dioxin, such as a garbage incinerator or a sintering equipment for iron ore.

[0008] The present invention combines the effective use of powdered activated carbon in the packed bed adsorption technology, the avoidance of the use of expensive adsorbent in the adsorbent injection exhaust gas treatment technology, and the combination of the adsorbent injection technology and the packed bed adsorption technology. Enables advanced exhaust gas treatment technology.

[0009]

(Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to an example of exhaust gas treatment of a sintering facility shown in FIG. Exhaust gas treatment comprising a sintering machine 1, an electric dust collector 2, an induction ventilator 3, an activated carbon or activated coke adsorbent packed bed 4, a chimney 5, and an adsorbent regenerating device 6, a separating device 7 for regenerated adsorbent and powdered adsorbent. In the equipment, exhaust gas discharged from the sintering machine 1 is dust-removed by the electric dust collector 2, and then introduced into the adsorbent packed layer 4, where dioxin and other harmful substances are adsorbed and removed. Some adsorbents are powdered in the packed bed. The adsorbent a having reduced adsorption performance is drawn out of the packed bed 4 and subjected to heat regeneration treatment in an inert gas atmosphere by the regenerating device 6, and the adsorbed dioxin is decomposed and removed by heating to regenerate the adsorption performance of the adsorbent a. You. Since the adsorbent a 'regenerated by the regenerating device 6 contains the powdered adsorbent b, the regenerated adsorbent a' and the powdered adsorbent b
Is separated, and the regenerated adsorbent a 'is returned to the packed bed 4 and recycled. Conventionally, when the powdered adsorbent b is returned to the packed bed 4,
Since the gas flow was hindered, it could not be returned to the packed bed 4 and was mostly used as fuel for steelworks because it was mostly carbon.

On the other hand, in the present invention, the powdered adsorbent b is supplied to the powdered adsorbent storage hopper 8 and the flue between the sintering machine 1 and the electrostatic precipitator 2 to blow the powdered adsorbent b. Adsorbs and removes dioxins and other harmful substances,
The powdered adsorbent b is collected by the electric dust collector 2. The recovered powdered adsorbent b 'is used as fuel for steelworks. For example, the adsorbed dioxin is returned to the sintering machine 1 and used as a substitute for coke breeze which is the fuel of the sintering machine, and the adsorbed dioxin is decomposed by combustion. Here, the entire amount of the powdered adsorbent can be used for blowing, but the blowing amount is adjusted according to the generated amount and the capacity of the electric dust collector. The excess powdered adsorbent can be used for direct combustion or as a blowing agent for other exhaust gas treatment devices.

[0011] The powdered adsorbent has been reduced in strength and powdered due to repeated use, and thus has been subjected to heat regeneration treatment many times. The specific surface area and the activity of the carbon-based adsorbent are increased by the heat regeneration treatment. Therefore, since the powdered adsorbent after regeneration has a larger specific surface area than a normal adsorbent, it has high adsorption performance, and has higher adsorption performance than a commercially available blowing agent. Furthermore, since it carries fine dust having an oxidizing activity such as potassium or iron, when returned to a sintering machine, it has better flammability than general coke breeze and adsorbed dioxin is decomposed efficiently.

(Embodiment 2) Hereinafter, another embodiment of the present invention will be described with reference to FIG. Incinerator 10, gas cooling tower 11, bag filter 12, induction ventilator 3, activated carbon or activated coke adsorbent packed bed 4, chimney 5, adsorbent regenerating device 6, separation device 7 for regenerated adsorbent and powdered adsorbent The exhaust gas discharged from the incinerator 10 is cooled in the gas cooling tower 11, dust is removed by the bag filter 12, introduced into the adsorbent packed bed 4, and dioxin and other harmful substances are adsorbed and removed. . Some adsorbents are powdered in the packed bed. The adsorbent a having reduced adsorption performance is withdrawn from the packed bed 4 and heated and regenerated in an inert gas atmosphere by the regenerating device 6, and the adsorbed dioxin is decomposed and removed by heating to regenerate the adsorption performance of the adsorbent a. Is done. Since the adsorbent a 'regenerated by the regenerating device contains the powdered adsorbent b, the regenerated adsorbent a' and the powdered adsorbent b are separated by the separating device 7, and the regenerated adsorbent a 'is filled with the packed bed. It is returned to 4 and used cyclically. Conventionally, when the powdered adsorbent b is returned to the adsorption tower, the flow of gas is hindered. Therefore, the powder adsorbent b cannot be returned to the packed bed.

On the other hand, in the present invention, a powdered adsorbent blowing device 9 is provided in the powdered adsorbent storage hopper 8 and the flue between the cooling tower 11 and the bag filter 12 to blow the powdered adsorbent b. Dioxin and other harmful substances are adsorbed and removed, and the powdered adsorbent b is collected by the bag filter 12. Since the recovered powdered adsorbent b 'is recovered as part of dust containing ash such as silica and alumina,
It is charged into the ash melting furnace 13 and subjected to melting processing. The dust collected in the present invention, compared to the dust that is subjected to normal ash melting treatment, has a powdered adsorbent that is carbon-based and is uniformly mixed with the dust. It can be used as fuel and efficient melting process is possible.

[0014]

According to the present invention described above, the effective use of the powdered adsorbent in the packed bed adsorption technology, the avoidance of the use of the expensive adsorbent in the adsorbent injection exhaust gas treatment technology, and the adsorbent injection technology and the packed bed adsorption are achieved. Combining technologies enables advanced and efficient exhaust gas treatment technology.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the overall configuration of a sintering apparatus for treating exhaust gas.

FIG. 2 is a diagram showing an example of the overall configuration of an incinerator exhaust gas treatment device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sintering machine 2 Electric precipitator 3 Induction ventilator 4 Adsorbent filling layer 5 Chimney 6 Adsorbent regeneration device 7 Adsorbent separation device 8 Storage hopper 9 Blowing device 10 Incinerator 11 Gas cooling tower 12 Bag filter 13 Ash melting furnace a, a 'adsorbent b, b' powdered adsorbent

Claims (4)

[Claims] An exhaust gas having a dust collector, a packed bed filled with a carbon-based adsorbent downstream thereof, a regenerating device for regenerating an adsorbent having reduced adsorption performance, and a separating device for separating the regenerated adsorbent from the powdered adsorbent. An exhaust gas treatment device, characterized in that a treatment device is provided with a blowing device for blowing a powdered adsorbent into an inlet flue of a dust collector. 2. The exhaust gas treatment apparatus according to claim 1, wherein the carbon-based adsorbent is activated carbon or activated coke. 3. The exhaust gas treatment apparatus according to claim 1, wherein the powdered adsorbent containing dust collected by the dust collector is charged into an exhaust gas generation facility. 4. The exhaust gas treatment device according to claim 1, wherein the powdered adsorbent containing dust collected by the dust collector is charged into the ash melting device.