JP2000205537A - Slag conveyor, melting apparatus and method for conveying slag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably obtain a highly crystalline slag having a high strength. SOLUTION: The melting apparatus 1 comprises an ash melting furnace 3 for melting ash, and a slag conveyor 20 for conveying molten slag 51 exhausted from the furnace 3 while cooling to exhaust it as the slag 53. In this case, the furnace 3 includes an exhaust nozzle 43 for extracting corrosive gas 57, and the conveyor 20 includes a bucket 23 for conveying the slag 52 supplied from a slag dropping unit 21 to an exhaust port 26, an opening/closing means 28 provided in the port 26, and an input unit 35 of high temperature gas 56 for gradually cooling the slag 51 between the unit 21 and the port 26. Further, the unit 35 includes a burner 38 for heating the gas 56, and an output unit for outputting the gas 56 to the vicinity of the unit 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slag transport device for transporting molten slag in which ash is melted while cooling and discharging the slag, a melting device having a melting furnace for melting ash and the slag transport device, and The present invention relates to a slag transport method for transporting molten slag while cooling it and discharging it as slag.

[0002]

2. Description of the Related Art A melting device for melting ash, for example, incinerated ash generated by incineration of general refuse, is capable of reducing the volume and completely detoxifying dioxins and other harmful substances in the incinerated ash. It has the advantage that the slag obtained by cooling the molten slag in which the incinerated ash is melted can be recycled and used effectively. For melting incineration ash, there are various melting devices such as a burner type surface ash melting furnace and an electric plasma ash melting furnace, which are put into practical use. The molten slag is recovered as a vitreous water-cooled slag because of its easy handling. Roadbed materials and aggregates are considered promising as effective destinations of slag, and slag with high strength is desired.

[0003] In order to obtain a crystalline slag of high strength suitable for the roadbed material, aggregate and the like for roads, the inventors adjusted the cooling rate and composition of the slag and studied the recovery as a slowly cooled slag. .

FIG. 7 is a schematic sectional view showing an example of a conventional melting apparatus. In the melting device 2, the molten slag 51 is dropped from the dropping port 4 of the ash melting furnace to the bucket 23 of the slag conveyor 20 and received, and is conveyed while being cooled to form the slag 53, which is collected from the outlet 33. At this time, the exhaust gas 59 generated in the ash melting furnace 3 is drawn into the slag conveyor 20 to prevent rapid cooling of the molten slag 51.

[0005]

However, the melting apparatus 2 of the prior art has the following problems. In other words, drawing the exhaust gas 59 of the ash melting furnace 3 into the slag conveyor 20 in order to prevent the quenching of the molten slag 51 requires that the flow of the exhaust gas 59 and the conveying direction of the molten slag in the bucket be the same, The temperature drop of the molten slag 51 and the temperature drop of the conveyed molten slag 51 proceed simultaneously, and it is difficult to maintain the molten slag 51 in a high temperature region. Furthermore, under the influence of corrosive gas contained in the ash melting furnace exhaust gas 59 at a high concentration,
The slag conveyor 20 may be corroded in a short time, which may hinder operation. In addition, the connection portion 14 from the ash melting furnace 3 to the slag conveyor 20 due to fluctuations in the internal pressure of the ash melting furnace 3 or the like.
The molten slag 51 does not fall directly into the bucket 23 of the slag conveyor, but adheres and accumulates on the inner surface of the connection portion 14 and the slag guide 41, which may severely block the falling passage of the molten slag.

An object of the present invention is to stably obtain a high-strength, highly crystalline slag.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a conveying method for conveying molten slag of ash supplied from a supply port provided at one end to a discharge port provided at the other end. An opening / closing means extending from the discharge port to prevent inflow and outflow of gas inside and outside the discharge port and for discharging the slag cooled by the molten slag during the transport; and the supply port. And an inflow portion provided between the discharge port and a high-temperature gas that gradually cools the molten slag supplied to the transport means.

[0008] The molten slag in which the ash is melted is supplied from a supply port provided at one end, and is dropped on one end side of the conveying means. The conveying means receives the dropped molten slag and conveys it to a discharge port provided at the other end. At this time, a high-temperature gas flows in from an inflow portion provided between the supply port and the discharge port.
Since the inflow and outflow of the gas inside and outside of the outlet are prevented, the high-temperature gas flows toward one end of the conveying means and gradually cools the molten slag supplied to the conveying means and conveyed. Slag. On the other hand, the slag generated in the process of transporting the molten slag while being gradually cooled by the transport means is transported to a discharge port provided at the other end of the transport means, and is discharged by the opening / closing means.

Further, a heating means is provided for heating the gas by flowing the gas into the inflow portion and heating the gas to the high temperature. At this time, the heating means may be provided so that the heated high-temperature gas can easily flow to one end of the slag transport device. The gas flowing into the inflow portion may be high temperature, but is not necessarily a high temperature gas because a heating means is provided. By flowing gas having a relatively low temperature into the inflow section, heat loss up to the inflow section can be reduced. Since the heating means is provided, the gas can be heated to a temperature required for gradually cooling the molten slag in the inflow portion to a sufficiently high temperature gas.

[0010] Further, an outflow portion for allowing a high-temperature gas obtained by gradually cooling the molten slag to flow out is provided near the supply port. By providing an outlet for the high-temperature gas near the supply port, the high-temperature gas gradually cooled from the molten slag prevents the molten slag from dropping from the melting furnace, prevents the molten slag from scattering around, and excessively melts the slag. To prevent cooling.

Another object of the present invention is to provide a melting apparatus having a melting furnace for melting ash generated in an incinerator and a slag conveying device for conveying the molten slag discharged from the melting furnace while cooling and discharging the slag as slag. The slag conveying device is achieved by any one of the above. The melting device having the slag conveying device according to any one of the above can stably generate a high-crystalline slag having high strength.

Further, the melting furnace is provided with an extracting means for extracting corrosive gas generated in the melting furnace. By extracting the corrosive gas in the melting furnace by the extracting means, it is possible to prevent highly corrosive gas from flowing into the slag conveying device and corroding the conveying means.

[0013] The object of the present invention is to convey molten slag in which ash has been melted, transporting the molten slag while cooling it, and discharging the molten slag as a slag. Is achieved by a slag conveying method in which the temperature is gradually cooled. By flowing a high-temperature gas in the direction opposite to the direction of transport of the molten slag, it is gradually cooled while maintaining the temperature effective for producing highly crystallized slag of the molten slag to stabilize high-strength, highly crystalline slag. Can be obtained.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a slag conveying device of the present invention,
An embodiment of a melting device and a slag conveying method will be described in detail with reference to the drawings. In FIGS. 1 and 4 to 6, the same structures and working parts are denoted by the same reference numerals.

FIG. 1 is a schematic sectional view showing a first embodiment of a melting apparatus according to the present invention. The melting device 1 according to the first embodiment melts incinerated ash obtained by incinerating, for example, municipal solid waste or sewage sludge into an incinerator, and gradually cools the slag to collect and effectively use the slag. Device. The melting device 1 is a smelting furnace (melting furnace) 3 for melting the above incinerated ash, and a slag transport for transporting the molten slag 51 in which the incinerated ash discharged from the ash melting furnace 3 is melted and discharging as slag. Slag conveyor 2 which is a device
0. The ash melting furnace 3 and the slag conveyor 20 are connected at a connection portion 14.

The ash melting furnace 3 is provided with an exhaust nozzle 43 as extraction means for extracting as a flue gas 59 a corrosive gas generated in the ash melting furnace 3 and a high-temperature gas 56 obtained by gradually cooling molten slag, which will be described later. A pressure measuring device or a manometer 6a for measuring the pressure in the ash melting furnace 3 is provided.

The slag conveyor 20 is a part of a conveying means 22 for conveying a molten slag 51 supplied from a slag dropping portion 21 as a supply port provided at one end to a discharge port 26 provided at the other end. A bucket 23 and an opening / closing means 28 extending from the discharge port 26 to prevent the inflow and outflow of gas inside and outside the discharge port 26 and to discharge the slag 53 cooled by the molten slag 51 during transportation; ,
An inflow section 35 is provided between the slag dropping section 21 and the discharge port 26 and inflows a high-temperature gas 56 as a high-temperature gas for gradually cooling the molten slag 51 supplied to the transporting means 22. Is provided with a pressure measuring device or manometer 6b for measuring the pressure on the end side of.

The transporting means 22 includes, for example, a wheel 24 (a wheel 24 at one end) in addition to the bucket 23.
a, a wheel 24b) on the other end side, a chain 25, and the like, which are provided in a case 27 forming the slag conveyor 20. The opening / closing means 28 has a first damper 30 and a second damper 31 provided on the extraction pipe 29.

The melting apparatus 1 of the first embodiment having the above structure operates as follows. That is, the molten slag 5
1 is supplied from the slag dropping unit 21 and drops into the bucket 23 a at one end of the slag conveyor 20. Bucket 2
3a receives the melted slag 51 that has flowed down and conveys it to the discharge port 26 provided at the other end of the slag conveyor 20. At this time, the high temperature gas 56 flows from the inflow portion 35 provided between the slag dropping portion 21 and the discharge port 26,
Since the opening / closing means 28 provided to extend to the discharge port 26 prevents the gas inside and outside the discharge port 26 from flowing in and out, the hot gas 56 flows toward one end of the slag conveyor 20. Then, the molten slag 51 in the bucket supplied and conveyed to the bucket 23 is gradually cooled to form the slag 53. On the other hand, the slag 5 transported by the bucket 23
3 is conveyed to a discharge port 26 provided at the other end of the slag conveyor 20, and is discharged by opening / closing means 28.

Next, the above operation will be described in more detail.
The molten slag 51 which is heated and melted to 1300 to 1400 ° C. in the ash melting furnace 3 passes through the connection part 14 between the ash melting furnace 3 and the slag conveyor 20 from the slag dropping port 4 and drops into the bucket 23 a located at one end. I do. The molten slag 51 moves at a predetermined speed while being cooled in the bucket 23, turns the bucket 23 upside down, and falls from the outlet 33. The opening / closing means 28 is of a double damper type, and has a first damper 30.
And the second damper 31 are alternately opened and closed to prevent leakage of outside air and outflow of inside air.

In the vicinity of the center of the slag conveyor 20, there is provided an inflow portion 35 for supplying a high-temperature gas 56 toward the melting furnace, and the high-temperature gas 56 is opposed to the conveying direction of the slag conveyor 20. By flowing, the bucket 23 near the slag dropping portion 21 of the slag conveyor is maintained at a temperature effective for producing highly crystallized slag so as to maintain the slow cooling rate of the molten slag in the bucket.
After passing through the connecting portion 14 of the ash melting furnace 3, it is introduced into the ash melting furnace 3 side.

The exhaust nozzle 43 provided in the ash melting furnace 3 extracts corrosive gas from the ash melting furnace 3 so that highly corrosive gas flows into the slag conveyor 20 and corrodes the conveying means 22. To prevent

FIG. 2 is a graph showing the relationship between the ultimate temperature of the molten slag subjected to the temperature control and the crystallization ratio. As shown by the curve 47, in order to crystallize the molten slag and obtain a high-temperature slowly cooled slag, it is necessary to increase the temperature by 1% from the melting temperature (the right end of the curve).
It is important to control the cooling temperature in the initial stage of cooling to 100 ° C.

FIG. 3 is a graph showing the relationship between the cooling rate of the molten slag, the diffraction intensity, and the rate of increase under a 1 mm screen. 110
The diffraction intensity of the first peak (curve 48) as an index of the crystallinity when the cooling rate to 0 ° C. is changed and the increase rate under a 1 mm screen (curve 49) as an index of the intensity are shown. The increase rate under a 1 mm sieve indicates the proportion of slag that has been pulverized and fined as a result of a slag pulverization test using a ball mill. The higher the rate, the greater the abrasion loss, that is, the lower the strength. As indicated by the curve 48, crystallization proceeds at a cooling rate of 500 ° C./h or less, and the first peak intensity increases. However, as the cooling rate increases, the diffraction intensity decreases, and at a cooling rate of 680 ° C./h or more, The peak based on the crystal disappeared. The change in the increase rate under the 1 mm screen as an index of the intensity is in good agreement with the diffraction intensity,
At a cooling rate of 500 ° C./h or less where the diffraction intensity is high, crystallization proceeds and the strength is high. On the other hand, when the cooling rate is higher than 500 ° C./h, crystallization does not proceed, and the amount of abrasion increases. That is, the strength is weak.

From these, in FIG. 1, the high-temperature gas 56 flowing from the inflow section 35 of the slag conveyor prevents the corrosive gas 57 in the ash melting furnace 3 from leaking into the slag conveyor 20 and cools the ash. The bucket 23 in the initial stage is kept warm, and the cooling rate of the molten slag in the bucket 23 is kept at 500 ° C./h or less. As a result, the recovered slag is gradually cooled while being kept warm for crystal growth in the initial cooling process, and is thus recovered as a high-strength slowly cooled slag 54. The surface of the slag mass on the bucket 23 that normally comes into contact with the atmosphere in the slag conveyer 20 is gradually cooled by the high-temperature gas 56 having a heat-retaining action, so that the slag has high crystalline strength.

Incidentally, the surface temperature of the gradually cooled slag 54 collected by the melting apparatus 1 of the first embodiment is about 200 ° C., the internal temperature is about 500 ° C., and the appearance is rocky and hard to break. The gradually cooled slag 54 is gray and has a density of 2.5 to 2.7 g /
cm3. Slowly cooled slag 54 recovered from ash melting furnace
The abrasion loss measured by the Los Angeles tester satisfied the aggregate application standard value, which is even stricter than the roadbed material application standard, and abrasion loss of 30% or less. The corrected CBR value was 80% or more, which satisfied the reference value for the upper subbase material. Further, as a result of the dissolution test, the slowly cooled slag 54 was found to satisfy the landfill standard value.

FIG. 4 is a schematic sectional view showing a second embodiment of the melting apparatus. In order to stably obtain a high-strength slag, the ash melting furnace 3 is a burner type surface melting furnace described in Japanese Patent Application No. 6-281779, for example. It is of the pyrolysis type. The ash 50 in the ash hopper 7 is introduced into the ash melting furnace 3 by the ash pusher 9. The ash 50 introduced into the ash melting furnace 3 is heated by the kerosene burner 10, and is heated to 1300 to 1400 ° C. at the slag port 12 to become a molten slag 51. Up to this point, low-boiling components containing corrosive gas in the ash are vaporized and exhausted as exhaust gas 59 from the exhaust nozzle 43. By extracting the pyrolysis gas 60 from the furnace top, the concentration of corrosive gas is reduced by half. can do.

An inflow section 35 is provided near the center of the slag conveyor 20, and a burner 38 as a heating means for heating a gas 58 flowing into the inflow section 35 is provided. The burner 38 heats the gas 58 to a high-temperature gas 56 as a high-temperature gas and causes the gas 58 to flow toward one end of the slag conveyor 20 or the ash melting furnace 3. Hot gas 5
6 is passed through the connecting portion 14 while maintaining the temperature of the bucket 23a near the slag dropping portion 21 of the slag conveyor so as to maintain the cooling rate of the molten slag in the bucket, and is introduced into the ash melting furnace 3 side. The exhaust gas of the corrosive gas inside is prevented from leaking into the slag conveyor 20 side.

The gas 58 to be flowed into the inflow portion may be a high temperature, but is not necessarily a high-temperature gas because the burner 38 is provided. Loss can be reduced.
Further, since the burner 38 is provided, the gas 58 can be heated to a temperature required for gradually cooling the molten slag in the inflow section 35 and turned into a high-temperature gas 56.

The molten slag 51 is collected from the slag outlet 12 through the connecting portion 14 between the ash melting furnace 3 and the slag conveyor 20 and collected in the bucket 23a. The molten slag 51 collected in the bucket 23 a
After 0 minutes, the slag is retained in the slag conveyor 20, and then the bucket 23 is turned upside down and collected from the outlet 33 of the outlet pipe. The bucket 23 is made of a 5 ton steel plate with 15 m of heat insulating material.
Use a lining with a thickness of m. The molten slag 51 dropped into the bucket 23 of the slag conveyor is heated from the melting temperature of 1350 ° C. to 1 by the heat retaining action of the high temperature gas 56 of 800 ° C. or higher flowing through the slag conveyor 20.
Slow cooling is performed at a cooling rate of 300 ° C./h in a high temperature region up to 100 ° C., and a crystalline high-strength slag 53 is formed. The structure and operation of other parts in the melting device 1 of the second embodiment are as follows:
This is the same as the melting device of the first embodiment.

The surface temperature, the internal temperature, the appearance, the color and the density of the gradually cooled slag 54 collected by the melting device 1 of the second embodiment are the same as those of the melting device of the first embodiment. . Further, the abrasion loss and the modified CBR value of the gradually cooled slag 54 measured by the Los Angeles tester also satisfied the reference values as in the case of the melting apparatus of the first embodiment. In addition, as a result of the dissolution test, the slowly cooled slag 54 was found to satisfy the landfill standard value.

FIG. 5 is a schematic sectional view showing a third embodiment of the melting apparatus. The melting device 1 according to the third embodiment is different from the melting device according to the second embodiment (FIG. 4) in that an outlet for heating a gas 58 flowing from the inlet 35 of the slag conveyor and for flowing out a high-temperature gas 56 generated. The difference is that it has 40. The outflow portion 40 is provided near the slag dropping portion 21, and the hot gas 56 is supplied to the molten slag 5 on the bucket 23.
1 is gradually cooled and flows out of the outlet 40 as the conveyor exhaust gas 62. The outlet 40 of the high-temperature gas 56 is connected to the slag dropping unit 21.
, The high-temperature gas 56, which has gradually cooled the molten slag, prevents the molten slag 51 dropped from the ash melting furnace 3 from falling, prevents the molten slag from being scattered around, and excessively disperses the molten slag 51. Prevent cooling.

The structure and operation of the other parts of the melting device 1 of the third embodiment are the same as those of the melting device of the second embodiment. The surface temperature, the internal temperature, the appearance, the color, the density, and the like of the gradually cooled slag 54 collected by the melting device 1 of the third embodiment were the same as those of the melting device of the second embodiment.
Further, the abrasion loss and the modified CBR value of the gradually cooled slag 54 measured by the Los Angeles tester also satisfied the reference values as in the case of the melting apparatus of the first embodiment. In addition, as a result of the dissolution test, the slowly cooled slag 54 was found to satisfy the landfill standard value.

FIG. 6 is a schematic sectional view showing a fourth embodiment of the melting apparatus. The melting device 1 of the fourth embodiment is different from the melting device of the third embodiment (FIG. 5) in that a burner 16 is provided at a connection portion 14 between the ash melting furnace 3 and the slag conveyor 20. The gas sealing function between the melting furnace 3 and the slag conveyor 20 is improved. The structure and operation of the other parts in the melting device 1 of the fourth embodiment, the quality of the gradually cooled slag generated, and the like are the same as those of the melting device of the third embodiment, and therefore description thereof is omitted.

The melting device 1 of the first to fourth embodiments is
By supplying high-temperature gas in the opposite direction to the direction of transport of the molten slag, highly crystalline slag can be obtained, and corrosion of the slag conveyor due to highly concentrated corrosive gas can be prevented. Slag can be manufactured.

Next, an embodiment of the slag conveying method of the present invention will be described with reference to FIG. The slag conveying method according to the present embodiment includes, for example, a molten slag 5 in which combustion ash is melted.
While cooling the molten slag 51, the molten slag 51 is gradually cooled by flowing a high-temperature gas 56, which is a high-temperature gas, so as to oppose the molten slag 51 in the opposite direction to the transport direction. By flowing the high-temperature gas 56 in a direction opposite to the conveying direction of the molten slag 51, the molten slag 51 is gradually cooled while maintaining a temperature effective for generating a highly crystallized product, and a high-crystalline slag of high strength is obtained. 53 can be obtained stably.

[0037]

According to the slag conveying device, the melting device or the slag conveying method of the present invention, high-strength, highly crystalline slag can be stably obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of a melting apparatus according to the present invention.

FIG. 2 is a graph showing the relationship between the ultimate temperature of a molten slag subjected to temperature control and the crystallization ratio.

FIG. 3 is a graph showing the relationship between the cooling rate of molten slag and the diffraction intensity, and the rate of increase under a 1 mm screen.

FIG. 4 is a schematic sectional view showing a second embodiment of the melting device.

FIG. 5 is a schematic sectional view showing a third embodiment of the melting device.

FIG. 6 is a schematic sectional view showing a fourth embodiment of the melting device.

FIG. 7 is a schematic cross-sectional view showing an example of a melting device according to the related art.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 melting device 3 ash melting furnace (melting furnace) 20 slag conveyor (slag transport device) 21 slag dropping portion (supply port) 22 transport means 26 discharge port 28 opening / closing means 35 inflow section 38 burner (heating means) 40 outflow section 43 exhaust Nozzle (extraction means) 51 molten slag 53 slag 56 high-temperature gas (high-temperature gas) 57 corrosive gas 58 gas

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Manabu Yamamoto 3-36 Takara-cho, Kure City, Hiroshima Prefecture Inside Babcock Hitachi Kure Research Laboratories Co., Ltd. (72) Shuhei Ishii 1-2-10 Isogo Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term in Babcock Hitachi, Ltd. Yokohama Engineering Center (reference) 3K065 AA24 AB03 AC03 BA01 HA02 HA05

Claims (6)

[Claims] A conveying means for conveying a molten slag of ash supplied from a supply port provided at one end to a discharge port provided at the other end; Opening / closing means for preventing the inflow and outflow of gas inside and outside the discharge port and discharging the slag cooled by the molten slag during the transfer, and the transfer means provided between the supply port and the discharge port. An inflow section through which a high-temperature gas for gradually cooling the supplied molten slag flows. 2. The slag conveying device according to claim 1, further comprising a heating means for flowing a gas into the inflow portion, heating the gas, and heating the gas to the high temperature. 3. The slag conveying device according to claim 1, wherein an outflow portion for discharging a high-temperature gas obtained by gradually cooling the molten slag is provided near the supply port. 4. A melting apparatus comprising: a melting furnace for melting ash generated in an incinerator; and a slag conveying device for conveying molten slag discharged from the melting furnace while cooling and discharging the slag as slag. The melting device according to claim 1, wherein the melting device is a melting device. 5. The melting apparatus according to claim 4, wherein the melting furnace includes extraction means for extracting corrosive gas generated in the melting furnace. 6. The molten slag in which ash has been melted is transported while being cooled and discharged as slag, and a high-temperature gas is flown so as to oppose the molten slag in a direction opposite to the transport direction of the molten slag to gradually cool the molten slag. Slag transport method.