JP3049170B2 - Swirling flow melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swirling flow melting furnace.
More particularly, the present invention relates to a swirling flow melting furnace for melting and solidifying fly ash, bottom ash, and the like generated when incinerating waste such as municipal solid waste and sewage sludge.

[0002]

2. Description of the Related Art Conventionally, waste such as municipal solid waste and sewage sludge has been incinerated as shown in FIG. 2 in order to sanitize, reduce the volume and stabilize the waste. Has been incinerated using The incineration residue generated by the incinerator 22 due to this incineration is mainly classified into fly ash discharged from exhaust gas treatment equipment 25 such as a dust collector 23 and a gas cooling chamber 24 and bottom ash extracted from the bottom of the incinerator 22. Is done.

[0003] Fly ash and bottom ash are generally landfilled at a final disposal site such as a marine landfill, and fly ash is fine particles having a particle size of several hundreds to several tens of microns mainly composed of ash in garbage. In some cases, heavy metals and very harmful dioxins are contained, and if such fly ash is landfilled as it is, it may cause secondary pollution and cause environmental pollution. On the other hand, the bottom ash is a so-called cinder composed of an inorganic substance such as ash, glass and metals and an unburned organic substance, and has a non-uniform and coarse shape as compared with fly ash. In general, those generated from fluidized bed incinerators generally used in refuse incineration plants are generally low in unburned organic matter, and the risk of secondary pollution during landfill is low, but landfill At present, there is a shortage of disposal sites, and it is desired that landfills be eliminated by recycling.

[0004] In view of the circumstances described above, in recent years, fly ash and bottom ash have been made more harmless and stable, and the volume has been reduced as a measure to prolong the life of landfills. Methods of processing have been researched and developed.

As the above-mentioned melting method, various types such as an electric resistance furnace using electric energy, a plasma melting furnace, a surface melting furnace using burner heating, and a swirling flow melting furnace have been proposed and developed for practical use.

On the other hand, the present applicant has previously developed a processing method for melting and solidifying incinerated ash such as fly ash or bottom ash or ash such as coal ash using a swirling flow melting furnace in the field of this kind of refuse treatment. I'm going more. (Japanese Patent Application No. 62-
187453, Japanese Patent Application No. 1-228869)

Incidentally, the above-mentioned swirling flow melting furnace has, for example, a structure shown in FIG.
First, the inside of the furnace 1 and the furnace wall are heated by the main burner 11 provided in the upper part of the swirling flow melting furnace 1 so that the temperature is maintained at a temperature higher than the temperature at which the ash can melt and flow down. At this time, in order to burn the fuel ejected from the main burner 11, combustion air is blown from the primary air supply pipe 9 and the secondary air supply pipe 10. The main burner 11 is composed of a fuel supply pipe 12 and a combustion air pipe 13 around the fuel supply pipe 12. The primary air supply pipe 9 is connected to the combustion air pipe 13. The secondary air supply pipe 10 is arranged so that the secondary air blowing direction is tangential to the furnace wall as viewed from a plane as shown in FIG.

Next, the ash in the storage hopper 6 is quantitatively cut out by the table feeder 7, dropped into the primary air supply pipe 9 via the valve 8, and burned through the primary air supply pipe 9. (Hereinafter referred to as primary air) and blown into the furnace 1 through the combustion air pipe 13 together with the primary air. The solid-gas two-phase flow composed of the ash and the primary air thus blown is heated while rotating on the furnace wall of the melting portion 14 in combination with the secondary air, and the ash is melted and turned into slag. The molten slag flows down along the furnace wall of the melting section 14, passes through the narrowing section 16 and the slag separating section 17, falls into the slag extracting section 15, and is discharged from that portion. After discharging, the molten slag is cooled and solidified.

In the swirling flow melting furnace, incineration ash such as fly ash and bottom ash can be melted and solidified as described above, whereby the volume can be reduced and harmlessness, stabilization and recycling can be achieved. However, since a large amount of exhaust gas is generated and about 50% of the heat required for melting is carried away by the exhaust gas, effective use of the heat of the exhaust gas is desired. On the other hand, incinerated ash etc. blown into the furnace is restricted to those having a particle size of 1 mm or less. Therefore, non-uniform and coarse shapes such as bottom ash that has been subjected to magnetic separation and the like to remove metals etc. are pulverized. However, it is necessary to supply the fine particles having a particle diameter of 1 mm or less, and a pulverizing facility is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to make it possible to effectively use the heat carried away by the exhaust gas and to use a nonuniform and coarse material such as bottom ash. It is an object of the present invention to provide a swirling flow melting furnace capable of melting dust having various shapes without grinding.

[0011]

In order to achieve the above object, a swirling flow melting furnace according to the present invention is provided with a slag for separating molten slag from a melting portion for turning molten slag while rotating a minute material to be melted such as ash. Separation section, a slag extraction section for extracting the separated molten slag, in this order in the cylindrical vertical swirling flow melting furnace having an exhaust gas duct on the side wall of the slag extraction section and having an exhaust gas duct on the side of the slag extraction section, A slag reservoir is provided at the bottom near the furnace body, and an inlet for the material to be melted is provided at the top.

[0012]

In the above construction, the slag reservoir is provided at the bottom of the exhaust gas duct of the swirling flow melting furnace near the furnace body, and the inlet for the material to be melted is provided at the upper portion thereof. Inhomogeneous and coarse-shaped refuse can be injected and melted by the exhaust gas heat exhausted, enabling effective use of exhaust gas and melting non-uniform and gross-shaped refuse such as bottom ash without crushing. Can be slagged.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same parts as those of the conventional technology are denoted by the same reference numerals. FIG. 1 is a cross-sectional explanatory view of a swirling flow melting furnace according to the present invention. The swirling flow melting furnace 1 shown in this embodiment basically includes an ash supply device 2, a combustion air supply device 3, and a furnace body 4.
And an exhaust gas duct 5.

The ash supply device 2 connects a table feeder 7 to a storage hopper 6 for storing ash such as coal ash discharged from a boiler and an industrial furnace and fly ash discharged from an incinerator. The combustion air supply device 3 is connected to a primary air supply pipe 9 via a valve 8.

The combustion air supply device 3 includes a primary air supply tube 9 and a secondary air supply tube 10 connected to a supply source (not shown), and connects the primary air supply tube 9 to the main burner 11. A combustion air pipe 13 provided on the outer periphery of the fuel supply pipe 12
The secondary air supply pipe 10 is connected to the melting portion 14 of the furnace main body 4 so that the blowing direction of the secondary air is tangential to the furnace wall when viewed from a plane.

The furnace main body 4 has a cylindrical vertical shape, and has a melting portion 14 at the upper portion for turning the ash into molten slag while rotating the ash, and a slag extracting portion 15 for discharging the molten slag at a lower portion. And the melting part 14 and the slag extraction part
A squeezed portion 16 and a slag separating portion 17 therebelow are provided between the portions 15.

The exhaust gas duct 5 is provided integrally with the furnace main body 4 on the side wall of the slag extraction section 15 of the furnace main body 4, and a slag reservoir 18 is formed inside the bottom of the furnace body 4 near the furnace main body 4. A weir 19 is provided, and an inlet 21 into which a relatively large melt 20 can be introduced is provided above the slag reservoir 18.

In the swirling flow melting furnace 1 having the above-described structure, ash and the like are melted and solidified in the following manner. That is, first, ash such as fly ash is stored in the storage hopper 6, and a relatively large bottom ash or the like 20 after magnetic separation is injected into the exhaust gas duct 5 from the input port 21 while the above-described prior art is used. In the same way as slag conversion of ash in a swirling flow melting furnace,
A main burner 10 provided at the upper part of the swirling flow melting furnace 1 heats the inside of the furnace main body 4 and the furnace wall to maintain the temperature at which the ash is melted and flows down. Next, the ash in the storage hopper 6 is quantitatively cut out by the table feeder 7, dropped into the primary air supply pipe 9 through the valve 8, and mixed into the primary air flowing through the primary air supply pipe 9,
The primary air is blown into the furnace main body 4 through the combustion air pipe 13, and the ash is melted into slag in the melting part 14.

The high-temperature exhaust gas generated during such an operation is discharged from the melting section 14 to the narrowing section 16 and the slag separating section 17.
After flowing through the exhaust gas duct 5 from the side wall of the slag extraction section 15 to the outside, the molten material 20 is heated and melted into slag when passing through the exhaust gas duct 5. The molten slag accumulates in the slag reservoir 18 and overflows from the weir 19 and is discharged together with the molten slag of ash such as fly ash. After discharging
This molten slag is cooled and solidified. In addition, those obtained by magnetically separating the metal from the material 20 to be melted such as bottom ash have a melting temperature of about 1250 ° C. or less, and a melting temperature of fly ash of 1300 to 1300 ° C.
The temperature is lower than 1400 ° C, and it is possible to make the molten slag sufficiently by the exhaust gas.

In this manner, a large amount of heat of the high-temperature exhaust gas generated in the operation process can be effectively used for melting the material 20 to be melted introduced into the exhaust gas duct 5. Also, since the calorific value is taken away by melting of the material to be melted 20 and the temperature of the exhaust gas decreases, low boiling components in the exhaust gas generated at the time of fly ash melting are easily trapped, and the wake gas including the exhaust gas treatment device such as a bag filter is used. The effect of preventing blockage of the flue and suppressing emission of harmful heavy metals into the atmosphere is produced.

In order to enjoy the above effect more effectively, an exhaust gas temperature measuring device is provided near the furnace main body 4 of the exhaust gas duct 5, and a heater is provided near the slag reservoir 18 if necessary. It is preferable to connect these devices to a conventional temperature control system (shown by a two-dot chain line in FIG. 1) of the melting section 14 so that the molten material 20 can be stably turned into molten slag at the same time as tapping. Is obtained. In addition, since the temperature of the exhaust gas in the downstream stream is stabilized, stable operation of an exhaust gas treatment device such as a bag filter can be performed.

[0022]

As described above, according to the swirling flow melting furnace according to the present invention, the amount of heat of the high-temperature exhaust gas generated in the melting portion can be effectively used, and uneven heat such as bottom ash can be obtained. Coarse shaped refuse can be melted without crushing.

Further, since the temperature of the exhaust gas is lowered, low boiling components in the exhaust gas generated when the fly ash is melted are easily trapped, thereby preventing clogging of the downstream flue including an exhaust gas treatment device such as a bag filter. It also has the effect of suppressing the emission of harmful heavy metals into the atmosphere.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a swirling flow melting furnace according to the present invention.

FIG. 2 is a processing flow chart of a municipal solid waste incinerator.

FIG. 3 is an explanatory sectional view of a conventional swirling flow melting furnace.

FIG. 4 is a sectional view taken along line XX of FIG. 3;

[Explanation of symbols]

1: swirling flow melting furnace 2: ash supply device
3: Combustion air supply device 4: Furnace body 5: Exhaust gas duct
6: Storage hopper 7: Table feeder 8: Valve
9: Primary air supply pipe 10: Secondary air supply pipe 11: Main burner 1
2: Fuel supply pipe 13: Combustion air pipe 14: Melting part 1
5: Slag extraction section 16: Squeeze section 17: Slag separation section 1
8: Slag pool 19: Weir 20: Melted material 2
1: Input port

Continuation of the front page (56) References JP-A-4-62312 (JP, A) JP-A-2-298714 (JP, A) JP-A-61-1913 (JP, A) JP-A-1-129544 (JP) , U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23J 1/00 ZAB F23G 5/32 ZAB F24J 1/08 ZAB

Claims (1)

(57) [Claims] A slag separating section for separating molten slag, a slag separating section for separating the molten slag, and a slag extracting section for extracting the separated molten slag. In a cylindrical vertical swirling flow melting furnace having an exhaust gas duct on the side wall of the slag extraction section in order from the top, a slag reservoir is provided at the bottom of the exhaust gas duct near the furnace body, and the material to be melted is charged at the top. A swirling flow melting furnace having an opening.