JP2000015210A - Dry distillation thermal decomposition melting combustion apparatus for waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover heavy metals in a slag by decreasing comparatively economically which is discharged from a dry distillation thermal decomposition melting combustion apparatus for a waste. SOLUTION: In a dry distillation thermal decomposition melting combustion apparatus for a waste wherein a thermally decomposed gas G and a thermally decomposed residue D are generated by thermal decomposition of a waste C in a dry distillation thermal decomposition reactor 2, a combustible material 1 in the thermally decomposed gas G and the thermally decomposed residue D is melted and burned in a melt combustion apparatus 4, and a molten slag F from the combustion apparatus 4 is discharged as a water-granulated slag F2, slag treating equipment A comprising a slag pit 30 for receiving the molten slag F from the combustion apparatus 4, a burner device 31 for heating the molten slag F1 in the slag pit 30, a slag-cooling water-tank 39 for making a water-granulated slag F2 by receiving the molten slag F1 which flows down from the slag pit 30, a cooler 34 for a combustion gas H extracted from the inside of the slag pit 30, and a purification treating device 35 for the combustion gas H from the cooler 34, is installed to decrease a heavy metal content in the discharged water-granulated slag F2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a dry distillation pyrolysis melting combustion apparatus for waste used for melting and burning waste such as municipal solid waste, and more particularly to an improvement in molten slag discharged from the melting combustion apparatus. The heavy metal was volatilized using the heat of combustion of the pyrolysis gas, and the volatilized heavy metal was cooled, solidified, separated and collected, so that the heavy metal content of the granulated slag discharged to the outside was significantly reduced. The present invention relates to an apparatus for pyrolysis melting and combustion of waste.

[0002]

2. Description of the Related Art Dry distillation pyrolysis and melting treatment of wastes has an excellent property that harmful substances such as dioxin released to the outside can be reduced, and its development has been promoted in various fields. FIG. 3 shows an example of a conventional dry distillation pyrolysis melting and burning apparatus for waste. The waste C supplied into the dry distillation pyrolysis reactor 2 by the supply device 1 is now cut off with air shut off. Then, it is heated to a temperature of 300 ° C. to 600 ° C. and converted into a pyrolysis gas G and a pyrolysis residue D.

[0003] The pyrolysis products formed inside the dry distillation pyrolysis reactor 2 are separated into a pyrolysis gas G and a pyrolysis residue D in a carry-out device 3, and the pyrolysis gas G of the former is melted and burned. It is sent to the device 4 and burned. Further, the latter pyrolysis residue D is sent to a separation device 5, from which relatively coarse incombustible solids N are removed, and the remaining fine combustible solids I are finely divided in a pulverizing device 6. After being pulverized I _O, it is supplied to the melting and burning device 4, and together with the pyrolysis gas G, the dust E from the waste heat boiler 7 and the dust collector 8, and the like, is mixed with 120.
Melt combustion at a temperature of 0 ° C. or higher. Further, the molten slag F formed in the molten combustion device 4 is granulated slag F _2.
And the combustion exhaust gas G _O from the melting and burning device 4 is discharged into the atmosphere through a waste heat boiler 7, a dust collector 8, a gas purification device 9, and a chimney 10.

The dry distillation pyrolysis reactor 2 is formed of a rotary dry distillation drum provided with a heating tube 11, and waste is put into a plurality of heating tubes 11 arranged in the longitudinal direction of the dry distillation drum. A heating gas K for heating is circulated and circulated.
In FIG. 3, 12 is a generator of heated gas K, 13 is a burner, 14 is a steam turbine power generation facility, 15 is a push-in fan, 16 is an induction fan, 17 is a vibration cooler, and 18 is storage of combustible fine powder. Tank, 19 is a pipeline, 20 is a circulation fan, 21
Is a damper device, 22 is fuel (oil or gas), 23
Is a waste pit and 24 is a crane.

The ash and dust E in the combustible fine powder I _O brought into the melting and burning apparatus 4 are not entirely converted into molten slag F in the melting and burning apparatus 4,
In reality, about 40% of ash and dust E of combustible fine powder I _O
The fly ash moves into the flue gas G _O as fly ash, and is discharged outside the melting and burning apparatus 4.

On the other hand, the combustion exhaust gas G from the melting and burning device 4
As described above, fly ash in _O is collected by the dust collector 8 and the like, and returned to the melting and burning device 4 as dust E. Therefore, heavy metals such as Pb, Zn, Cd, and Cr contained in the dust E are also melted by the melting and burning device. 4 will be reblown. as a result,
The concentration of heavy metals in the melting and burning apparatus will gradually increase, and accordingly, the concentration of heavy metals in the molten slag F formed in the melting and burning apparatus 4 will also increase, and the concentration of the granulated slag discharged to the outside will increase. The heavy metal content can increase, causing various problems in reusing granulated slag.

[0007]

SUMMARY OF THE INVENTION The present invention relates to the above-mentioned problems in the conventional dry distillation pyrolysis melting and burning of waste,
That is, it is an object of the present invention to solve the problem that the heavy metal content of the granulated slag discharged from the melting and burning apparatus increases, and the molten slag F is reduced for about a predetermined time in a reducing atmosphere using the combustion heat of the pyrolysis gas. By maintaining the temperature at a high temperature of 1300 ° C., the heavy metal is volatilized from the molten slag F, and the volatilized heavy metal is discharged together with the combustion gas. It is an object of the present invention to provide an apparatus for pyrolysis melting and burning of waste, which can be made into crushed slag.

[0008]

According to the first aspect of the present invention, a waste is pyrolyzed in a dry distillation pyrolysis reactor to generate a pyrolysis gas and a pyrolysis residue. The combustible material is melted and burned in the melting and burning apparatus, and the waste slag from the melting and burning apparatus is discharged as granulated slag. A slag pit for receiving the molten slag, a burner device for heating the molten slag in the slag pit, a slag cooling water tank for receiving the molten slag flowing down from the slag pit and forming granulated slag, and combustion extracted from the slag pit A slag treatment device consisting of a gas cooling device and a purification device for purifying combustion gas from the cooling device is provided to reduce the heavy metal content of the granulated slag to be discharged. It is intended to.

According to a second aspect of the present invention, in the first aspect of the present invention, the fuel for the burner device is converted to a pyrolysis gas, the cooling device for the combustion gas is changed to a water spray type cooling device, and the combustion gas is further purified. The device is a bag filter device, and the combustion gas from the bag filter device induced by the induction fan is supplied into the melting and burning device to be reburned.

According to a third aspect of the present invention, in the first aspect of the present invention, the combustion air supplied to the burner device is preheated by the combustion gas extracted from the inside of the slag pit, and based on the concentration of carbon monoxide in the slag pit. Thus, the supply amount of combustion air is controlled to maintain the inside of the slag pit in a reducing atmosphere.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the amount of the combustion gas attracted by the attraction fan is controlled based on the temperature in the slag pit, and the amount of the pyrolysis gas to be supplied to the burner device is reduced. The temperature in the slag pit is maintained at a predetermined value by adjusting the supply amount.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall system diagram of a waste carbonization pyrolysis melting and burning apparatus according to an embodiment of the present invention, and FIG. 2 is an overall system diagram of a slag treatment apparatus A forming a main part of the present invention. In FIGS. 1 and 2, the same members as those of the waste carbonization pyrolysis melting and burning apparatus shown in FIG. 3 are denoted by the same reference numerals. FIG.
The description of the same members as those described above is omitted.

In FIG. 1 and FIG.
4a is an outflow path of the molten slag F, and 4b is a high-temperature combustion exhaust gas.
Sus G_ODischarge path, 30 is a slag pit, 31 is a burner
, 32 is a push-in fan, 33 is a heat exchanger, 34 is combustion
Gas H cooling device, 34a is a discharge device, 34b is a discharge device
A valve, 34c a storage tank, 35 a combustion gas H purifying device, 3
5b is a discharge valve, 35c is a storage tank, 36 is an induction fan, 3
6a is a motor, 37 is a CO concentration control device, 37a is a CO
Concentration detection sensor, 38 is a temperature controller, 38a is temperature
Detection sensor, 39 is slag cooling water tank, 39a is slag
Conveyor, 39b is cooling water, 40 is granulated slag F_TwoSavings
Reservoir, 41 is an inlet for combustion gas H, G₁・ G _TwoIs pyrolysis
Gas, FF₁Is molten slag, F_TwoIs granulated slag, W is
Cooling water.

A slag processing apparatus A constituting a main part of the present invention
Is melting and combustion apparatus slag pit 30 for receiving molten slag F flowing down from 4, a burner device for holding the molten slag F ₁ in the slag pit 30 to a predetermined temperature 31
A cooling device 34 for cooling the combustion gas H extracted from the inside of the slag pit 30, a purification device 35 for removing and recovering heavy metals contained in the cooled combustion gas H, and an attraction for extracting the combustion gas H from the slag pit 30 The slag pit 30 is maintained in a reducing atmosphere to promote the volatilization of heavy metals contained in the molten slag F ₁ and the combustion gas H containing volatile gases of heavy metals.
Is extracted from the slag pit 30, and heavy metals in the combustion gas H condensed and solidified by cooling in the cooling device 34 are collected and removed in the combustion gas purification device 35.

The slag pit 30 is provided below the molten slag outflow passage 4a of the melting and burning device 4 and receives the molten slag F flowing down through the outflow passage 4a.
At the ceiling of the slag pit 30, a burner device 31 is provided, and the molten slag F in the slag pit 30 is provided.
₁ is about 1300 ° C. due to the heat of combustion of the burner device 31.
It is kept at the temperature before and after.

[0016] said to the burner apparatus 31 part G ₁ of the pyrolysis gas G is supplied as a fuel, in the present embodiment shown in FIGS. 1 and 2, the temperature control device as described below 38 by controlling the attraction air volume of induction fan 36 by the burner unit feed amount of the pyrolysis gas G ₁ to 31 (suction quantity) was adjusted thereby about the temperature of the molten slag F ₁ in the slag pit 30 1300 It is kept at ° C. Of course, any method may be used for the type of fuel to be supplied to the burner device 31, the method of supplying the fuel, the method of controlling the supply amount, the method of controlling the temperature in the slag pit, and the like.

The combustion air “a” of the burner device 31 is supplied by a pushing fan 32 and a heat exchanger 33.
The air a preheated by the combustion gas H from inside the slag pit 30 is supplied. Further, the supply amount of the combustion air a is controlled by the CO
By controlling the air blowing amount of No. 2, the inside of the slag pit 30 is adjusted to always have a reducing atmosphere.

The temperature inside the slag pit 30 is about 1300 ° C.
The reason why the atmosphere is kept at a high-temperature reducing atmosphere of 1400 ° C. is that Pb, Zn, Cd, Cr and the like contained in the molten slag F ₁ are easily volatilized, and the vaporization of these heavy metals is promoted. In FIGS. 1 and 2, the inside of the slag pit 30 is maintained in a reducing atmosphere by changing the supply amount of the combustion air a by the CO concentration control device 37. Any method may be used for maintaining the in a reducing atmosphere.

[0019] combustion gas H produced in the slag pit 30 by the operation of the burner apparatus 31, the volatile gases of heavy metals in the previously described molten slag F ₁ are included in a large amount. The combustion gas H containing a large amount of the heavy metal volatile gas is
The air is extracted from the slag pit 30 by the operation of the induction fan 36, and is introduced into the cooling device 34 through the heat exchanger 33.

In the present embodiment, a water spray type cooling device is used as the cooling device 34, and the combustion gas H is heated to about 1300 ° C. to 1 ° C. by contact with the sprayed cooling water W.
It is cooled from a high temperature of 400 ° C. to a temperature of about 160 ° C. Further, the heavy metal gas in the combustion gas H is condensed and solidified by contact with the spray water W, and a part thereof is discharged to the outside through the discharge device 34a and the discharge valve 34b together with the cooling water W, and is discharged to the storage tank 34c as the discharge Wa. Collected.

In the embodiment shown in FIGS. 1 and 2,
Although a water spray type cooling device is used, any other cooling device for the combustion gas H may be used. For example, a waste heat boiler or the like may be used.

The combustion gas H cooled by the cooling device 34 is continuously introduced into a combustion gas purifying device 35, where solidified heavy metals and other impurities remaining in the combustion gas H are collected and removed. Further, the removed heavy metals and other impurities Wb are collected into the storage tank 35c through the discharge valve 35b.

In the present embodiment, a bag filter device is used as the combustion gas H purifying device 35, and a condensed solid heavy metal or the like is condensed by the induction fan 36 while the combustion gas H passes through the bag filter. Collected in the filter media on the outer surface of the bag. Further, the combustion gas H that has been purified by passing through the bag filter is continuously jetted inward from a combustion gas supply port 41 provided in the melting and burning apparatus 4 through a pipe 42, and is here injected into the combustion gas H. CO remaining
Is burned. The combustion gas H extracted from the slag pit 30 in the reducing atmosphere contains a large amount of CO,
In addition, these COs are supplied to the cooling device 34 or the bag filter device 3.
5 is not sufficiently removed.

In the present embodiment, the bag filter device 3
The combustion gas H having a high concentration from 5 is recombusted in the melting combustion device 4, but when the emission amount of the combustion gas H is small, after chemically removing CO, the mixture is discharged to the atmosphere. Of course, it may be released. Furthermore, although in the present embodiment be supplied to the burner unit 31 as a part G ₁ of the pyrolysis gas G from carbonization pyrolysis reactor 2,
After contact allowed by dehydrochlorination process dehydrochlorination treatment agent hydrated lime such pyrolysis gas G _1, it may be supplied to the burner apparatus 31. By subjecting to pyrolysis gas G ₁ to the dehydrochlorination process, is reduced to the extent that the hydrogen gas concentration chloride in the combustion gases H negligible, the heat exchanger 33
, Etc., can be prevented from occurring.

[0025]

According to the present invention, the molten slag F flowing out of the melting and burning apparatus is maintained at a temperature of about 1300 ° C. for a predetermined time in the slag pit 30 maintained in a reducing atmosphere, and the molten slag F ₁ The heavy metal is volatilized, and the combustion gas H in the slag pit 30 containing the volatile gas is cooled and purified to collect the heavy metal. as a result,
Heavy metals in the molten slag F ₁ discharged from the slag pit 30 are greatly reduced, and the granulated slag F ₂ discharged to the outside is reduced.
Also reduces the heavy metal content and makes recycling easier.
Further, the recovered heavy metals can be reused, which is advantageous in terms of effective use of resources. Furthermore, slag pit 30
When using a pyrolysis gas G ₁ is as fuel for the burner device 31 can be achieved even more effective use of waste energy, it is possible to reduce the heavy metal removal treatment costs of the slag. In addition, when the pyrolysis gas subjected to the dehydrochlorination treatment is used as the fuel for the burner device 31, the concentration of hydrogen chloride in the combustion gas H from the slag pit 30 decreases, and the heat Hot corrosion can be prevented. INDUSTRIAL APPLICABILITY As described above, the present invention can reduce the heavy metals in granulated slag discharged from a dry distillation pyrolysis melting and burning apparatus to the outside relatively efficiently at a relatively low cost, and can significantly reduce the heavy metals. To play.

[Brief description of the drawings]

FIG. 1 is an overall system diagram of an apparatus for dry distillation pyrolysis melting and burning of waste according to an embodiment of the present invention.

FIG. 2 is an overall system diagram of a slag processing device showing a main part of the present invention.

FIG. 3 is an overall system diagram of a conventional waste distillation pyrolysis melting and burning apparatus for waste.

[Explanation of symbols]

 A: slag processing equipment, C: waste, D: pyrolysis residue, E
… Dust, FF₁… Molten slag, F_Two… Granulated slag,
GG₁・ G_Two... pyrolysis gas, I ... combustibles, I _O… Combustible
Fine powder, G_O... combustion exhaust gas, H ... combustion gas, a ... combustion air
Gas, W: cooling water, Wa / Wb: effluent, 2: dry distillation pyrolysis
Reactor, 3 ... Unloading device, 4 ... Melting combustion device, 4a ... Melting
Slag outflow path, 4b: high-temperature combustion exhaust gas discharge path, 5 ... minutes
Separation device, 6: crusher, 7: waste heat boiler, 8: dust collector,
9 gas purifier, 30 slag pit, 31 burner
Installation, 32: push-in fan, 33: heat exchanger, 34: combustion
Gas cooling device, 35 ... Combustion gas purification device, 36 ... Induction
Drawing fan, 37 ... CO concentration control device, 38 ... Temperature control device
Installation, 39… Slag cooling water tank, 40… Granulated slag storage tank,
41 ... combustion gas inlet.

Claims (4)

[Claims] 1. Pyrolysis of waste in a dry distillation pyrolysis reactor to generate a pyrolysis gas and a pyrolysis residue, and melt combustion of the pyrolysis gas and the combustibles in the pyrolysis residue in a melting and burning apparatus. A slag pit for receiving the molten slag from the melting and burning apparatus, wherein the molten slag from the melting and burning apparatus is discharged as granulated slag. A slag cooling water tank that receives molten slag flowing down from the slag pit and turns it into granulated slag; a cooling device for combustion gas extracted from the slag pit; and combustion from the cooling device. A slag treatment device comprising a gas purification treatment device and a heavy metal content of the granulated slag discharged is reduced, and the pyrolysis melting and burning apparatus for waste is characterized by the following features. Place. 2. A bag filter, wherein the fuel of the burner device is a pyrolysis gas, the cooling device of the combustion gas is a water spray type cooling device, and the purification device of the combustion gas is a bag filter device. 2. The apparatus for dry distillation pyrolysis melting and burning of waste according to claim 1, wherein the combustion gas from the apparatus is supplied into the melting and burning apparatus for reburning. 3. The combustion air supplied to the burner device is preheated by combustion gas extracted from inside the slag pit, and the supply amount of combustion air is controlled based on the concentration of carbon monoxide in the slag pit. 2. The apparatus for dry distillation pyrolysis melting and burning of waste according to claim 1, wherein the apparatus is maintained in a reducing atmosphere. 4. The temperature in the slag pit is controlled by controlling the amount of combustion gas attracted by the attraction fan based on the temperature in the slag pit and adjusting the amount of dry distillation pyrolysis gas supplied to the burner device. 3. The apparatus for dry distillation pyrolysis melting and burning of waste according to claim 2, wherein the apparatus is kept at a value.