JPH053868Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention supplies air to the incineration residue (incineration ash) of solid waste such as municipal waste and industrial waste to remove unburned carbon in the incineration ash. an ash melting furnace that processes incinerated ash by burning it and using the heat generated by the combustion as a melting heat source;
In particular, it concerns the shape of the grate plate that forms the hearth.

[Prior Art] Conventionally, as a hearth for this type of ash melting furnace, a plurality of flat grate plates were laid in series with the ends of adjacent grate plates stacked vertically in the direction of transport of the incinerated ash. However, it is known that the hearth has a step-shaped hearth that is slanted as a whole. In a hearth in which a plurality of grate plates are stacked in a stepped manner, there is a gap between the stacked grate plates, so this gap can be used as an air injection port to blow combustion air into the incinerated ash. . The ash melting furnace supplies such combustion air to burn unburned carbon in the incinerated ash, and melts the incinerated ash using the generated heat of combustion as a melting heat source.

[Problems that the invention aims to solve] However, in conventional ash melting furnaces, although combustion air is supplied, when the molten slag (molten ash = molten metal) flows along the hearth, the molten metal is Because the molten metal spreads over each flat grate plate, there was a problem in that the molten metal receded and flowed at the overlap of the grate plates, causing it to form in icicles at the lower end of the grate plate located at the tip of the hearth. For this reason, it was difficult to operate the furnace stably.

As a means to prevent such sticking of the molten metal, irradiation with fire using an oil burner or the like is considered, but this is inappropriate because it requires a large amount of fuel such as oil and causes an increase in running costs.

The purpose of this invention is to improve separation of molten metal from unmelted ash by concentrating the molten metal flowing on the grate plate on the same grate, prevent molten slag from sticking on the grate, and enable stable operation. Our objective is to provide an ash melting furnace.

[Means for solving the problem] The present invention supplies air to the incinerated ash discharged from the main combustion furnace to burn unburned carbon in the incinerated ash,
In an ash melting furnace that melts incinerated ash using the combustion generated heat as a melting heat source, a grate plate forming a hearth for melting and transferring the incinerated ash in the discharge direction is provided, and the upper surface of the grate plate is attached to this. The slanted guide surface collects the molten metal generated from the incinerated ash that is melted while being transferred along the V-shape, and the trough that allows the collected molten metal to flow down in the above-mentioned transfer direction. The leading edge of the grate plate is made to protrude obliquely from the valley in consideration of the gravitational movement component of the molten metal flowing down the guide surface.

[Function] Since the upper surface of the grate plate is formed in a V-shape, the molten metal generated from the incinerated ash that is melted while being transferred along the grate plate flows along the V-shaped inclined guide surface. The molten metal is collected in one place and flows down along the V-shaped valley in the direction in which the incinerated ash is transported. Moreover, the inclined guide surface allows the leading edge of the grate plate to protrude obliquely around the valley in consideration of the gravitational movement component of the molten metal flowing down the guide surface, so that melting is carried out from within the width of the leading edge of the grate plate. They are all collected in a trough on the same grate plate and flow down along the grate, without flowing out or falling onto the grate plate. This improves separation from unmelted ash and improves the flow of the molten metal.
Solidification of molten metal on the grate board is prevented. Therefore,
Stable and easy operation is possible.

[Example] Hereinafter, an example of the present invention will be described based on the accompanying drawings.

The system shown in Figure 1 consists of a rotary kiln type main combustion furnace 1 that incinerates solid waste such as municipal waste.
is connected to the end of the main combustion furnace 1, and burns the incineration residue (incineration ash) 8 containing unburned carbon discharged from the main combustion furnace 1 while transferring it onto the hearth, and releases the heat. Incinerated ash 8 to molten metal (molten slag) 10
It consists of a post-combustion ash melting furnace 2.

The ash melting furnace 2 includes a furnace body 3 covered with a refractory heat insulating material, and a downwardly sloping passage 4 is formed inside the furnace body. The main combustion furnace 1 is located on the upper part of the furnace body 3.
Hopper 3a as an inlet to receive ash from
is formed, and the hopper communicates with the upper upstream side 4a of the passage 4. Further, the lower end of the furnace body 3 is connected to a slag discharge passage 11 and continues to a slag cooling water tank.

In the passageway 4 of the furnace body 3, a plurality of grate plates 5 made of ceramics such as silicon carbide are arranged in a stepped manner.
It forms a sloping fire bed. On each grate board 5,
High-temperature electric heater 6 made of a rod-shaped silicon carbide heating element
is integrated. Reference numeral 9 denotes an air nozzle (diffuser pipe) that blows out high-temperature combustion air sent in from both sides of the passage 4, and this air nozzle 9 is arranged within the interval that occurs at the overlapping part of the adjacent grate plates 5. There is.

In FIGS. 2 to 5, each grate plate 5 has a grate plate main body 50 and a flange portion 51 for preventing molten metal from getting around.
The upper surface is continuous and forms the upper surface of the grate plate 5. As clearly seen in FIG. 3, the upper surface 52 of this grate plate 5 is formed in a V-shape in order to collect the molten metal and allow it to flow down. Specifically, the V-shaped upper surface 52 of the grate plate has an inclined guide surface 52a that collects the molten metal generated from the incinerated ash 8 that is transferred and melted in one place, and a sloped guide surface 52a that collects the molten metal generated from the incinerated ash 8 while being transferred and melts the incinerated ash. 8, and a trough portion 52b for flowing downward in the transfer direction. This V-shaped trough 52b is provided at the center of the grate plate 5 so as to run linearly in the direction in which the incinerated ash 8 is fed. Further, as can be seen from FIG. 2, the grate plate 5 is formed to have a feather-like shape when viewed from above. That is, the leading edge of the grate plate 5 projects obliquely from the side to the valley portion 52b, and the rear edge of the grate plate 5 is diagonally recessed from the side with the valley portion 52b as the center.

In this embodiment, the slope α of the V-shaped inclined guide surface 52a of each grate plate 5 is approximately 10°, and the inclination angle (feed angle) β of the leading and trailing edges of the grate plate 5 is 5 to 15°. . However, these angles can be set to appropriate values depending on the circumstances. In particular, the latter feed angle β is
The characteristics change depending on the value of the inclination angle γ of the grate plate 5 when forming the hearth, which will be described later. Further, the V-shaped valley portion 52b is provided at the center of the grate plate 5 and runs linearly toward the feeding direction of the incinerated ash 8; It may be in any position or may be slightly curved. In short, the shape of the upper surface of the grate plate 5 takes into consideration the moving direction component of the molten metal due to gravity, and the molten metal does not flow down from the entire leading edge of each grate plate 5, but is collected in the valley portion 52b, and flows down from the valley portion 52b. It suffices to form it in a V-shape that allows for

As shown in FIG. 6, the grate plate 5 has a flange 5
1 is placed on the downstream side in the direction of transfer of the incinerated ash 8, and the flange 51 of the upper grate plate 5 is placed on the downstream side in the direction of transfer of the incinerated ash 8.
are arranged so as to form a stepped hearth. These grate plates 5 forming a stepped hearth are arranged so that an envelope connecting the upper corners of each of the flanges 51, that is, the upper surface of the hearth, forms a constant inclination angle θ. In this embodiment, each grate plate 5
The grate plates 5 are arranged so that the individual inclination angles γ are about 5°, and the inclination angle θ of the entire hearth connecting the upper corners of the flanges 51 is about 20°.
However, these angles of inclination of the grate plate 5 and the slope of the inclined guide surface 52a can be changed to appropriate angles depending on the circumstances.

On the other hand, as shown in FIGS. 4 and 5, each grate plate 5 is integrally provided with a heater protector 53 made of an insulating material at the lower part of the grate plate main body 50. An insertion hole 54 for the electric heater 6 is bored in the hole 54 . This heater protector 5
3 and the insertion hole 54 drilled therein also take into consideration the movement position shift caused by the moving component of the molten metal due to gravity, and when viewed from above, the leading edge and the trailing edge of the grate plate 5 are as shown in FIG. It is provided so as to be inclined by the feed angle β. As shown in FIGS. 8 and 9, the electric heater 6 is inserted into the insertion hole 54 of the heater protector 53 from both sides and is integrated with the grate plate 5. That is, as a result of being integrated with the grate plate 5, the electric heater 6 is protected from the inflow of molten metal and efficiently heats the grate plate 5. In addition, 55 is the grate board main body 50
The hole for the thermocouple is shown.

Now, solid waste 7 such as municipal waste is supplied from the input port to the main combustion furnace 1, where it is ignited by an auxiliary combustion burner and then oxidized by combustion air. It is introduced into the melting furnace 2. At that time, unburned carbon remains in the incineration ash 8, but the amount is preferably 7 to 25% by weight, preferably 10% by weight.
Main combustion furnace 1 so that it remains in the range of ~20% by weight
The combustion within is controlled. Specifically, it is made to remain by adjusting the input amount of waste, the amount of combustion air, the stoker feed rate in a stoker type furnace, the rotation speed in a rotary kiln type furnace, etc.

The incineration ash 8 containing unburned carbon is transferred to the hopper section 3a.
The unburned carbon is layered on the grate plate 5 in the melting furnace 2 through the air nozzle 9, and the unburned carbon is burned by the high-temperature combustion air blown out from the air nozzle 9, heated by the heat generated at that time, and becomes molten slag or molten metal 10. Become. This molten metal 1
0 is collected on the inclined guide surface 52a of each V-shaped grate board 5 toward the trough 52b, becomes a single stream along the trough 52b, and flows to the sprue part (the most extreme part of the grate board 5) 5d. flows to During this period, in order to promote combustion and melting of the incinerated ash 8, the temperatures of the grate plate 5 are as follows: 900°C in the preheating zone, 1100°C in the combustion zone, 1300°C in the melting zone, and 1350°C.
It is controlled in several sections, such as the sprue section 5d. In addition, 20% of the combustion air is used in the preheating zone and 20% in the combustion zone.
The amount is controlled to 60% and 20% in the melting zone, and the combustion and melting of the incinerated ash 8 is performed efficiently.

The molten metal is collected in a V-shaped valley 52b along the inclined guide surface 52a of the grate plate 5. At this time, the trough portion 52b of the inclined guide surface 52a protrudes by the feed angle β in consideration of displacement of the molten metal due to gravity. They are all collected in the trough 52b on the same grate plate 5 without falling upward, and flow down along the trough 52b. Therefore, unlike in the case of a flat grate plate, the molten metal does not solidify into an icicle shape within the width of the leading edge of the grate plate 5, and the molten metal flows smoothly down on the grate plate 5. In this way, it flows over the grate plate 5 and the sprue 5d
The molten metal (molten slag) 10 discharged from the slag falls into a slag cooling water tank (not shown) through a slag discharge passage 11, where it is cooled and solidified.

On the other hand, the combustion exhaust gas is sucked by a blower (not shown) in the same direction as the molten slag 10 flows, and is discharged from the flue 16 while preventing the sprue portion 5d of the grate plate 5 from being cooled.

The large pusher 12 and the small pusher 13 agitate and transfer the incinerated ash 8 through a coordinated operation, thereby contributing to the control of combustion and melting of the incinerated ash 8, as well as preventing bridging of the incinerated ash 8 and forcibly discharging molten unsuitable materials. It is something to do. When sending out the large pusher 12, the controller 15 monitors whether the number of output pulses per unit time (feeding speed) generated from the encoder 13 belonging to the large pusher 12 falls below a predetermined value. If it rotates, it is determined that there is a sign of slag fixation. Also,
When the number of output pulses generated from the encoder 13 per unit time is zero, that is, when the large pusher 12 stops, the number of output pulses generated from the encoder 13 until the large pusher 12 stops from its original position is Compare the integrated value with a predetermined set value, and if the integrated value has not yet reached the set value,
It is determined that the stoppage was caused by clinker generation.
When such a clinker is detected, the controller 15 strengthens the energization of the electric heater 6 in the part where the clinker is generated, and also turns on the large pusher 1.
2. The combination operation of the small pusher 13 peels off and discharges the stuck slag.

[Effects of the invention] As described above, in the ash melting furnace of the invention, the molten metal generated from the incinerated ash that is melted while being transferred along the grate plate is 1/1 along the V-shaped inclined guide surface.
The collected molten metal flows down along the V-shaped valley in the direction in which the incinerated ash is transported. Therefore, separation from unmelted ash is improved, the flow of the molten metal is improved, and solidification of the molten metal on the grate plate is prevented.

In addition, considering the gravitational movement component of the molten metal flowing down the inclined guide surface, the leading edge of the grate plate is made to protrude obliquely around the valley, so that the melting occurs within the width of the leading edge of the grate plate. They are all collected in the valley on the same grate plate, without coming out to the sprue or falling onto the grate plate. That is, the molten metal is placed on a flat grate plate or simply on a V
Unlike in the case of a letter-shaped grate board, there is no receding flow at the overlap of the grate boards 5. Therefore, molten metal will not leak into the overlapped seams of the grate board, so
It becomes easy to protect the electric heater that heats the grate board. Furthermore, since the melt does not solidify in the form of icicles on the leading edge of the grate plate 5, stable and easy operation is possible.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the ash melting furnace of the present invention connected to the main combustion furnace, Fig. 2 is a top view of the grate plate, Fig. 3 is a front view of the grate plate, and Fig. 4 is a side view of the grate plate, Fig. 5 is a cut end view taken along line V-V in Fig. 3, Fig. 6 is a side view of the hearth formed by connecting grate plates, and Fig. 7 is a side view of the grate plate. FIG. 8 is a top view of the grate plate with an electric heater attached thereto, and FIG. 9 is a front view thereof. In the figure, 1 is the main combustion furnace, 2 is the ash melting furnace, 3 is the furnace body, 5 is the grate plate, 6 is the electric heater, 8 is the incinerated ash,
9 is an air nozzle, 10 is a molten metal, 12 is a large pusher, 13 is a small pusher, 50 is a grate board body, 5
1 is the flange, 52 is the upper surface of the grate board, 52a is the inclined guide surface, 52b is the valley, 53 is the heater protector, 54
indicates the insertion hole.

Claims (1)

[Scope of utility model registration request] The incinerated ash is melted in the ash melting furnace, which supplies air to the incinerated ash discharged from the main combustion furnace to burn the unburned carbon in the incinerated ash, and uses the generated heat of combustion as a melting heat source to melt and process the incinerated ash. a grate plate forming a hearth for transporting in the discharge direction while the grate plate is being transported; The collected molten metal is formed into a V-shape by the troughs that flow down in the transfer direction, and the leading edge of the grate plate is centered around the troughs in consideration of the gravity movement component of the molten metal flowing down the inclined guide surface of the grate plate. An ash melting furnace characterized by a diagonal protrusion.