JP3901376B2 - Burner ash melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a burner ash melting furnace using fine combustibles as fuel.
[0002]
[Prior art]
Recently, as a burner ash melting furnace, it is obtained by drying high calorie waste such as plastics, papers, woods, etc. among wastes such as municipal waste, and then crushing to a size of several millimeters or less, for example Some use fine-grain combustibles (hereinafter referred to as fluff) as burner fuel.
[0003]
As shown in FIG. 7, this type of burner type ash melting furnace has a furnace body 51 for heating and melting ash by a heating burner 52, and an ash supply for supplying ash into the furnace body 51. The apparatus 53 is comprised.
The furnace body 51 is formed with a cylindrical primary combustion chamber 61 and a secondary combustion chamber 63 communicated with the primary combustion chamber 61 through an opening 62, and a bottom wall portion 51a serving as a hearth is secondly formed. Inclined downward from the secondary combustion chamber 63 toward the primary combustion chamber 61, and an ash supply port 64 is formed in the side wall 51 b upstream of the bottom wall 51 a of the furnace body 51.
[0004]
The primary combustion chamber 61 is divided into a lower combustion space 61a and an upper combustion space 61b by an annular projecting portion 65 provided at an intermediate position in the height direction, and the burner 52 is provided on the upper wall portion 51c. It has been.
In the upper combustion space 61b, primary combustion air is supplied from the surroundings in the tangential direction so that the residence time of the fluff as fuel is made as long as possible. In the lower combustion space 61a, the primary combustion air is drawn from the surroundings. It is supplied in the radial direction and the inside is stirred.
[0005]
Further, the ash supply device 53 is provided with an ash charging hopper 71 whose lower part is connected to the supply port 64 of the furnace body 51 and an ash pushing pusher device 72 disposed at the lower part of the ash charging hopper 71. Yes.
In the above configuration, the ash supplied to the secondary combustion chamber 63 in the furnace body 51 by the pusher device 72 is first dried by the high-temperature combustion exhaust gas flowing from the primary combustion chamber 61 through the opening 62, Next, the dried ash moves to the primary combustion chamber 61 where it is melted to form molten slag, and from a slag outlet 66 formed on the opposite side of the furnace body 51 from the ash supply device 53, a granulated pit. 54 is dropped.
[0006]
[Problems to be solved by the invention]
According to the configuration of the burner ash melting furnace described above, the fuel fluff is a combustible material pulverized to a few millimeters or less, but this fluff contains large particles or lumps. Thus, they cannot be completely combusted in the primary combustion chamber 61 and scatter to the secondary combustion chamber 63 side in advance.
[0007]
For this reason, compared with the case where liquid fuels, such as oil, are utilized, the temperature distribution in a furnace will differ greatly. That is, when the fluff is used, the furnace temperature becomes the highest in the intermediate portion between the primary combustion chamber 61 and the secondary combustion chamber 63, and therefore the temperature in the primary combustion chamber 61 becomes low, and the molten slag is extracted. Becomes difficult.
Then, an object of this invention is to provide the burner type ash melting furnace which can extract | melt molten slag smoothly.
[0008]
[Means for Solving the Problems]
In order to solve the above problem, a burner type ash melting furnace of the invention will be the bottom wall portion together when the ash supply port is formed is inclined from one end to the other end to one end and fine A primary combustion chamber is formed on one end side in the furnace body having a heating burner that uses granular combustibles as fuel, and the other end side in the furnace body is connected to the primary combustion chamber through an opening. A secondary combustion chamber is formed, and a slag outlet for extracting molten slag is formed in the bottom wall where the temperature in the furnace between the primary combustion chamber and the secondary combustion chamber becomes the highest , upstream of the slag outlet In addition, the dam part for guiding the molten slag moving from the upstream side to both sides is formed along the periphery of the slag outlet, and the downstream side of the dam part is gradually made lower than the upstream side, The molten slag that moves through both sides of the weir part is the downstream edge of the slag outlet It is obtained by configured to drop into Luo slag extraction mouth.
[0009]
According to the above configuration, even when the burner fuel is a fine combustible material such as a fluff, the peak of the furnace temperature can be brought near the outlet of the molten slag, and therefore the extraction of the molten slag can be smoothly performed. Done.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a burner type ash melting furnace in an embodiment of the present invention will be described with reference to FIGS.
The burner type ash melting furnace in the present embodiment uses, as its fuel, wastes such as municipal waste, high-calorie waste such as plastics, papers, and woods, after drying, for example, several millimeters or less. It uses fine combustibles (hereinafter referred to as fluff) obtained by crushing to size.
[0011]
That is, as shown in FIG. 1, this burner type ash melting furnace is provided with a heating burner 4 and a furnace body 1 for melting ash, and an ash supply for supplying ash into the furnace body 1. The apparatus 2 and the fluff supply apparatus 3 for feeding the fluff into the burner 4 are configured.
The furnace body 1 is formed with a cylindrical primary combustion chamber 11 and a secondary combustion chamber 13 communicated with the primary combustion chamber 11 through an opening 12, and a bottom wall 1a as a hearth is a primary wall. Inclined downward from the combustion chamber 11 toward the secondary combustion chamber 13, and an ash supply port 14 is formed on one side wall 1 b upstream of the bottom wall 1 a of the furnace body 1. Yes.
[0012]
Further, the primary combustion chamber 11 is divided into a lower combustion space 11a and an upper combustion space 11b by an annular projecting portion (throttle portion) 15 provided at an intermediate position in the height direction, and an upper wall portion 1c thereof. In addition, the burner 4 is provided. In addition, the aperture ratio by the protrusion part 15 is set to about 0.5, for example.
In the upper combustion space 11b, as shown in FIG. 2, primary combustion air is supplied at a predetermined injection speed (for example, about 80 m / s) from upper injection nozzles 21 provided in six locations on the peripheral wall 1d and in a tangential direction. ), A swirling flow is generated inside, and the residence time of the fluff as the fuel of the burner 4 is made as long as possible.
[0013]
In addition, as shown in FIG. 3, primary combustion air enters the lower combustion space 11a from a lower blowing nozzle 22 provided at four locations on the peripheral wall 1d and in the radial direction at a predetermined blowing speed (for example, about 100 m / s), and the inside is stirred so that combustion is sufficiently performed.
And in the center position of the bottom wall part 1a corresponding to the opening part 12 of the said furnace main body 1, the planar view for extracting molten ash, ie, molten slag, is elliptical shape (others may be circular shape, for example). A slag outlet 23 is formed, and a dam portion (of course, formed of a refractory material) 24 is provided on the upstream side of the slag outlet 23, and from the upstream side to the downstream side. The molten slag S that moves to the slag is distributed to both sides by the weir part 24 and guided to the edge on the downstream side of the slag outlet 23 so as to drop into the slag outlet 23.
[0014]
As shown in FIGS. 4 and 5, the plan view shape of the dam portion 24 is an elliptical shape along the periphery of the slag outlet 23 (if the slag outlet is circular, the dam portion is also circular. The height is gradually lowered from the upstream side to the downstream side. To be precise, in order to drop the molten slag from the peripheral edge on the downstream side, only the portion is not formed with the weir portion, and thus is formed in a horseshoe shape.
[0015]
The fluff supply device 3 includes a storage hopper 31 for storing fluff, a weighing hopper 32 for cutting out the fluff in the storage hopper 31 by a predetermined amount, and a predetermined amount of fluff cut out by the measuring hopper 32 as a rotary valve. A blower 35 and an air transport pipe 36 for air-transporting continuously to the burner 4 via the 33 and the ejector 34 are configured. Of course, the burner 4 has combustion air, and the primary combustion chamber 11 and the secondary combustion chamber 13 have primary and secondary combustion air at a plurality of locations (also referred to as tertiary, quaternary, etc., depending on the location). From the combustion air supply pipe 37.
[0016]
In the above configuration, the ash supplied to the primary combustion chamber 11 in the furnace body 1 by the ash supply device 2 is dried and heated by the combustion heat of the burner 4 and passes through the opening 12 to the secondary combustion chamber 13 side. Move to.
In the middle of this, that is, in the vicinity of the opening 12, the molten slag S is divided into left and right by the weir 23 and moves to the secondary combustion chamber 13 side. In this portion, the fluff that has not been burned in the primary combustion chamber 11 is completely It burns and the furnace temperature reaches its maximum (for example, a temperature of about 1400 ° C. or higher). In other words, the molten slag S bypasses the weir 23 at the place where the furnace temperature is highest, and during this time, the molten slag S is sufficiently heated to maintain a good molten state.
[0017]
Accordingly, the molten slag S having a good fluidity goes around the downstream side of the slag outlet 23, smoothly enters the slag outlet 23 from the downstream peripheral edge, and falls into the granulated pit 5.
As described above, since the slag outlet 23 is provided at the intermediate portion between the primary combustion chamber 11 and the secondary combustion chamber 13, the fluff that has not been completely combusted in the primary combustion chamber 11 is completely combusted in this vicinity. The temperature in the furnace becomes the highest, so that the flow of the molten slag becomes good and is smoothly extracted from the slag outlet 23.
[0018]
In addition, when the state of the furnace temperature which concerns on this invention and a prior art example is shown, it will become like the graph of FIG.
As can be seen from FIG. 6, even when the burner fuel is a fluff, as shown by the solid line, the peak in the furnace temperature is higher than that of the conventional ash melting furnace (shown by the broken line). Accordingly, the molten slag can be smoothly and stably extracted.
[0019]
Further, since the ash supply device 2 is provided at a location closest to the primary combustion chamber 11, the ash supplied into the furnace body 1 can be sufficiently dried, and the particles contained in the fluff are large. Unburned matter such as things and lumps can be dropped on the preheating layer of the bottom wall portion 1a of the primary combustion chamber 11 to promote combustion.
[0020]
【The invention's effect】
As described above, according to the configuration of the present invention, even when the burner fuel is fine combustible material such as fluff, the peak of the furnace temperature can be brought near the outlet of the molten slag. Can be smoothly extracted.
In addition, since the ash supply device is provided at the location closest to the primary combustion chamber, the ash supplied into the furnace body can be sufficiently dried, and the particles contained in the fine combustibles are large. Unburned matter, such as lumps and lumps, can be dropped onto the preheating layer on the bottom wall of the primary combustion chamber, preventing scattering of unburned content to the secondary combustion chamber, that is, monoxide in the exhaust gas. Carbon can be reduced, and stable combustion and melting are possible.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of a burner type ash melting furnace in an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA of FIG.
3 is a cross-sectional view taken along the line BB in FIG.
FIG. 4 is a cross-sectional view of a main part of the burner type ash melting furnace of the embodiment.
FIG. 5 is a view taken along the line CC in FIG. 4;
FIG. 6 is a graph comparing furnace temperature distributions of the ash melting furnace of the same embodiment and a conventional ash melting furnace.
FIG. 7 is a cross-sectional view showing a schematic configuration of a burner ash melting furnace in a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Furnace main body 1a Bottom wall part 1b Side wall part 2 Ash supply apparatus 3 Fluff supply apparatus 4 Heating burner 11 Primary combustion chamber 12 Opening part 13 Secondary combustion chamber 14 Supply port 23 Slag extraction outlet 24 Weir part

Claims (1)

One end of the furnace body bottom wall portion together when the ash supply port is formed on one end having a heating burner to fuel and will be inclined toward the other side granules combustibles from one end In addition, a primary combustion chamber is formed, and a secondary combustion chamber communicated with the primary combustion chamber through the opening is formed on the other end side in the furnace body, and the primary combustion chamber and the secondary combustion chamber are connected to each other. A slag outlet for extracting molten slag is formed in the bottom wall where the temperature in the furnace becomes the highest, and a weir for guiding the molten slag moving from the upstream side to the upstream side of this slag outlet The slag outlet is formed along the periphery of the slag outlet, and the downstream side of the dam part is gradually made lower than the upstream side so that the molten slag moving through both sides of the dam part is transferred to the slag outlet. It is configured to drop into the slag outlet from the downstream edge of the Burner type ash melting furnace for.

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