JP3861397B2 - Internal melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal melting furnace for melting incineration ash containing unburned ash discharged from municipal waste incinerators and various incinerators.
[0002]
[Prior art]
Wastes such as municipal waste and sewage sludge were incinerated at the incineration facility, and the incinerated ash and dust generated were conventionally disposed of in landfills. However, there is a problem of depletion of landfill sites and groundwater contamination due to the elution of toxic heavy metals, so the need for weight reduction / volume reduction and detoxification by melting is increasing.
[0003]
Against this background, when incinerating waste in a waste incinerator, the waste is incinerated (gasification pyrolysis) to leave unburned in the incinerated ash, and the incinerated ash containing this unburned in the downstream An internal melting furnace that reduces the amount of heat supplied from the outside has been proposed by burning in an ash melting furnace and using the heat generated by the combustion as the main melting heat source of ash, and some actual processing has been performed.
[0004]
FIG. 3 is a perspective view of a conventional internal melting furnace. In the figure, a is an internal melting furnace. b is a furnace body. c is an incineration ash storage tank. d is a hearth connected to the lower part of the incinerated ash storage tank c. e is a combustion air nozzle disposed upstream of the hearth d. f is an auxiliary burner provided on the upper part of the furnace body b, and g is a plasma torch provided on the side part on the downstream side of the furnace body b. h is a pusher for sending the incineration ash in the incineration ash storage tank c to the hearth d. i is a molten slag.
[0005]
In such an internal melting furnace a, the incineration ash is melted by the combustion heat of the unburned portion contained in the incineration ash and the heat of the auxiliary combustion device such as the small plasma torch g and the kerosene burner f introduced as a melting aid. The molten slag i is continuously discharged from the hearth d, dropped into a water-sealed slag cooling unit (not shown) connected to the hearth d, rapidly cooled and solidified to form water-cooled slag, and then conveyed to a slag pit by a conveyor. The The air that burns the unburned components in the incinerated ash is heated by the steam and the internal melting furnace outlet exhaust gas, and then supplied to the combustion air nozzle e as high-temperature air. The furnace inner wall of the furnace body b is used as a radiant heat transfer surface.
[0006]
[Problems to be solved by the invention]
However, in the above internal melting furnace a, if the amount of ash discharged from the waste incinerator and the amount of ash to be melted in the melting furnace are not balanced, the molten slag is not melted in the molten slag due to excessive ash amount on the melting furnace side. Ash may be mixed. In addition, the residence time in the furnace is short, and there is an unburned portion that is discharged without generating heat in the furnace.
[0007]
The present invention was devised to solve the above-mentioned problems, and even if mixing of unmelted ash due to excessive ash amount occurs on the melting furnace side, the ash is completely melted by the sump, An object of the present invention is to provide an internal melting furnace in which the melting treatment capacity is improved by increasing the residence time of the combustion gas in the furnace by swirling flow to increase the combustion efficiency in the furnace.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, there is provided an internal melting furnace for melting incinerated ash containing unburned components and RDF using combustion generated heat of combustible components in the ash as a main melting heat source. The melting furnace consists of a combustion part and an ash melting part.The combustion part is connected to an incineration ash storage tank, a hearth connected to the lower part of the incineration ash storage tank and having a combustion air nozzle at the bottom, and incineration ash in the incineration ash storage tank. It consists of a pusher that pushes out to the hearth, the ash melting part has a horizontal cylindrical shape, the hearth of the combustion part is connected tangentially to one end of the bottom of the ash melting part, the other end of the ash melting part is Connected to the slag cooling section, an auxiliary burner is connected in the tangential direction at one end of the ash melting section, forming a swirling flow of combustion gas in the ash melting section, and forming a molten slag reservoir at the bottom of the ash melting section An internal melting furnace is provided. Note that RDF is a solid waste fuel, and its operation will be described later.
[0009]
Next, the operation of the present invention will be described.
The incineration ash containing unburned components is pushed out of the incineration ash storage tank by the pusher to the hearth of the combustion section. The incinerated ash that is pushed out is burned by the high-temperature air ejected from the combustion air nozzle on the hearth and melted by the heat to form molten slag, which flows down from the hearth to the ash melting section downstream. To do. This molten slag contains unmelted ash that does not melt completely, and the combustion gas from the combustion part contains fly ash, but the combustion gas from the combustion part is contained in the ash melting part. A swirling flow is formed by the combustion gas from the auxiliary combustion device, and the unmelted ash and fly ash are melted while swirling along the cylindrical furnace inner wall of the ash melting portion. Since the combustion gas swirls in the cylindrical ash melting portion, the residence time in the furnace becomes longer, the ash can be completely melted, and the melting processing capacity is improved. The molten slag falls into the slag cooling section and rapidly solidifies.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of the present invention, and FIG. 1 is a cross-sectional view of an internal melting furnace according to the present invention. FIG. 2 is an AA arrow view of FIG.
In the figure, 1 is an internal melting furnace for melting the incinerated ash 12 containing unburned components. The internal melting furnace 1 includes a combustion part 2 and an ash melting part 3.
[0011]
The combustion unit 2 includes an incineration ash storage tank 6, a hearth 5 connected to the lower part of the incineration ash storage tank 6 and provided with a combustion air nozzle 4 at the bottom, and the incineration ash 12 in the incineration ash storage tank 6 to the hearth 5. The pusher 7 is pushed out. The combustion air nozzle 4 has a large number of air holes, and a plurality of the combustion air nozzles 4 are arranged.
[0012]
The ash melting part 3 has a horizontal cylindrical shape. One end of the bottom of the ash melting part 3 is connected to the hearth 5, and the other end is connected to the slag cooling part 8. One end of the upper part of the ash melting part 3 is connected to an auxiliary combustion device 9 such as a temperature rising burner or plasma in the tangential direction.
[0013]
Next, the operation of the embodiment of the present invention will be described.
Incinerated ash 12 containing unburned components discharged from the waste incinerator is pushed out from the incinerated ash storage tank 6 to the hearth 5 of the combustion unit 2 by the pusher 7. The incinerated ash 12 that has been pushed out is burned by the high-temperature air ejected from the combustion air nozzle 4 on the hearth 5 and melted by the heat to become molten slag 13, downstream from the hearth 5. It flows down to the ash melting part 3 of the ash. The molten slag 13 contains unmelted ash that does not melt completely, and the combustion gas from the combustion section 2 contains fly ash, but the ash melting section 3 has a combustion section. The combustion gas 10 from 2 and the combustion gas from the auxiliary combustion device 9 flow tangentially into the ash melting portion 3 to form a swirling flow 11 of combustion gas in the ash melting portion 3. The molten ash and fly ash are melted while swirling along the cylindrical furnace inner wall of the ash melting portion 3. Since the combustion gas 10 swirls in the cylindrical ash melting part 3, the residence time in the furnace becomes longer and the combustion efficiency in the furnace becomes higher. As a result of the formation of the hot gas and the hot water reservoir, the ash can be completely melted, and the melt processing capacity is improved. The molten slag 13 falls into the slag cooling unit 8 and rapidly solidifies.
[0014]
The present invention is not limited to the above-described embodiment. In the above-described embodiment, the melting of incineration ash containing unburned components is described. Needless to say, various changes can be made without departing from the gist of the present invention, for example, solidified fuel (RDF (Refused Derived Full)) can be introduced and used as a heat source for melting ash.
[0015]
【The invention's effect】
As described above, according to the present invention, the molten slag containing the unmelted ash melted in the combustion section is converted into the cylindrical ash melting section on the downstream side and the high-temperature combustion gas from the combustion section and the auxiliary combustion. It melts along the inner wall surface of the ash melting part by the swirl flow formed by the combustion gas from the apparatus. Therefore, even if unmelted ash is contained in the molten slag on the combustion part side, the unburned ash is swirled with the combustion gas on the ash melting part side, and the residence time in the furnace is lengthened to increase the combustion efficiency in the furnace. In addition, the ash can be completely melted because the hot water reservoir is formed, and the melting processing capacity can be improved. Also, the fly ash contained in the combustion gas from the combustion section also melts in the ash melting section, adheres to the wall surface, and then flows down to the hot water reservoir, so the amount of fly ash in the exhaust gas is small and the burden on the exhaust gas treatment equipment is reduced. Excellent effects such as being reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an internal melting furnace according to the present invention.
FIG. 2 is a view taken in the direction of arrows AA in FIG.
FIG. 3 is a perspective view of a conventional internal melting furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Internal melting furnace 2 Combustion part 3 Ash melting part 3a Hot water stopper 4 Combustion air nozzle 5 Furnace floor 6 Incineration ash storage tank 7 Pusher 8 Slag cooling part 9 Combustion device 10 Combustion gas 11 Swirling flow 12 Incineration ash 13 Molten slag

Claims (1)

An internal melting furnace that melts incinerated ash containing unburned components and RDF using combustion generated heat of ash in ash as a main melting heat source, the internal melting furnace comprising a combustion part and an ash melting part, The combustion section has a part where the combustible matter in the incineration ash on the upstream side is burned and a part that flows down as molten slag of the incineration ash on the downstream side, and is connected to the incineration ash storage tank and the lower part of the incineration ash storage tank. Composed of a combustion air nozzle on the upstream side of the bottom and a descending gradient hearth toward the outlet, and a pusher that pushes the incineration ash in the incineration ash storage tank to the hearth, and the ash melting part is generated in the combustion part The molten slag containing the unmelted ash is a part that completely melts the unmelted ash, has a horizontal cylindrical shape, and the hearth of the combustion section is tangential to one end of the bottom of the ash melting section It is connected to, the swirling flow of combustion gas combustion gas generated in the combustion section to the ash melting portion Formed, the other end of the ash melting portion is provided continuously to the slag cooling section, burner air device in the tangential direction of the end of the ash melting portion upper is connected and the ash melting portion, pivoting by combustion gas generated in the combustion portion An internal melting furnace characterized in that a swirling flow of combustion gas in the same direction as the flow is formed, and a hot water reservoir for molten slag is formed in the ash melting portion.

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