JPH09243047A - Waste fusing facility equipped with slag cleaner, and manufacture of granulated slag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To roughly zero the heavy metal pollution of granulated slag by discharging the granulated slag primarily cleaned at the end of a conveyor by a nozzle, and cleaning this with a washing conveyor, and also cleaning it at the end by a nozzle. SOLUTION: Fused slag C falls into a slag water-cooling vessel 6, and becomes granulated slag D1, and then it is conveyed up onto water surface by the slag conveyor 7 within a water cooling vessel 6. The granulated slag D1 in the vicinity of the uppermost part of the slag conveyor 7 is cleaned in the position where it is exposed onto the surface of the water blown by a primary cleaning nozzle 8. The slag D1 from which a great part of the slag cleaning water F adhering to the surface is washed off is successively thrown into the slag washing vessel 9 provided under it. The granulated slag D1 which has dropped into the lower tank of the slag washing vessel 9 is cleaned again by the pure water E from the secondary cleaning nozzle 11 at the uppermost part of the slag washing vessel 9 while being conveyed up by a washing conveyor 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a waste melting treatment facility for melting incineration residue from a refuse incinerator, fly ash, municipal solid waste, etc., and is attached to the melting treatment facility. Waste with a slag cleaning device, by improving the granulated slag treatment system so that high quality granulated slag with almost no heavy metal contamination can be obtained without increasing running costs. The present invention relates to a melting treatment facility and a method for producing a water washing slag using the same.

[0002]

2. Description of the Related Art In recent years, in order to reduce the volume and detoxify the incineration residue and fly ash discharged from a refuse incinerator, a melting and solidifying method such as incineration residue has attracted attention and has been put to practical use. .
The volume of incineration residue etc.
This is because it can be reduced to 2 to 1/3, and it is possible to prevent elution of harmful substances such as heavy metals, reuse molten slag, and extend the life of the final landfill disposal site.

[0003] Thus, the melting and solidifying method for the material to be melted, such as the incineration residue, includes arc melting furnaces, plasma arc furnaces,
A method of melting and solidifying a material to be melted by electric energy using an electric resistance furnace, etc., and a method of melting and solidifying a material to be melted by combustion energy of fuel using a surface melting furnace, a swirling melting furnace, a coke bed furnace, etc. When the waste incineration facility and the power generation equipment are co-located, the former method of using electric energy is used, and when the power generation equipment is not co-located, the latter combustion energy is used. Each method is widely adopted.

FIG. 2 shows an example of generation of water granulated slag in a conventional melting furnace. In FIG. 2, 21 is a melting furnace, 22 is an outlet, 23 is a slag water cooling tank, 24 is water granulated slag, 25 is a slag conveyor, and 26 is a slag receiving tank, and melts a material to be melted in the melting furnace 21. The molten slag generated by this is dropped into the slag water cooling tank 23 storing the cooling water through the outlet 22, where the water granulated slag 24
Becomes The generated granulated slag 24 is discharged into the slag receiving tank 26 by the slag conveyor 25 provided in the water cooling tank 23. Incidentally, the water granulated slag 24 discharged into the slag receiving tank 26 usually has a water content of 3 to 5 wt%, and an amount of water corresponding to the water adhered and the evaporated water lost by evaporation is It is replenished into the water cooling tank 23 as appropriate.

As described above, the material to be melted (molten slag) melted in the melting furnace is rapidly cooled by being poured into the cooling water to become glassy granulated slag. The granulated slag 24 thus formed contains some of the heavy metals present in the incineration residue, but these substances are physically and chemically more stable. It is enclosed in the slag in the state, and as a result, the elution of heavy metals from the water granulated slag 24 is significantly suppressed. For example, the landfill standard for industrial waste regulates the elution value of lead, which is a heavy metal that is particularly problematic in landfill, to 0.3 mg / l or less, but the granulated slag 24 has an elution value for this lead. Of course, the elution values for other regulated substances are also below the regulated values.

By the way, the water granulated slag 24 is produced by consuming a large amount of energy for melting and has a characteristic that the hardness is extremely high.
Therefore, it is not economical to simply dispose of by landfill, and it is necessary to actively promote its effective use from the viewpoint of resource economy. Actually, concrete filler, roadbed material, embankment material, backfill material, building block Research and development are being carried out in various fields regarding the application to materials and the like.

When the water granulated slag 24 is used as a concrete filler or a roadbed material, it is desirable to determine the elution standard of heavy metals for each application from the viewpoint of ensuring its safety, but at this time, However, there is still no established elution standard. However, in these applications, most of the granulated slag 24 is used in a state of being in direct contact with the soil, and therefore the elution standard is set in view of the current soil environmental standard. It is stipulated that securement of safety is guaranteed by this.

On the other hand, according to the soil environmental standards, the elution value of lead, which is a heavy metal, is regulated to 0.01 mg / l or less, which is an extremely strict regulation value. On the other hand, the granulated slag 24 produced in the conventional melting furnace 21 is
There is no case where heavy metals such as lead are leached from the slag itself in excess of the regulation values of the existing soil environmental standards, and this has been verified through many leaching tests.
However, the cooling water attached to the granulated slag 24 (usually in an amount of 3 to 5 wt% as described above) is considerably contaminated by heavy metals. As a result, lead compounds and the like contained in the adhered water are separated and eluted from the outer surface of the granulated slag 24, resulting in soil contamination exceeding the standard value.

Therefore, in order to promote the effective use of the water granulated slag 4, the material to be melted is completely melted so that there is no unmelted portion, thereby eliminating the elution of heavy metals from the water granulated slag. At the same time, it is important to keep in mind the contamination by the cooling water for water granulation and to stably manufacture high quality water granulation slag with excellent safety.

[0010]

SUMMARY OF THE INVENTION The present invention prevents the above-mentioned problems in water granulated slag produced in a conventional melting furnace, that is, the elution of heavy metals from the water granulated slag itself is prevented. The purpose is to solve the problem that heavy metal pollution may occur due to the pollution of cooling water for water granulation that has adhered, and by eliminating almost all the heavy metal pollution, excellent safety is achieved. The present invention provides a waste melting treatment facility equipped with a slag cleaning device capable of producing high-quality water granulated slag, and a method for producing water granulated slag using the same.

[0011]

According to the present invention, in a waste melting treatment facility for producing granulated slag, a slag water cooling tank 6 having a slag conveyor 10 for receiving a molten slag C, and the slag water cooling tank 6 are provided. Slag washing tank 9 having a washing conveyor 10 for receiving water granulated slag D ₁ from
And a slag secondary washing water nozzle 11 provided near the slag outlet side of the slag washing tank 9 for injecting fresh water E,
The secondary cleaning wastewater H ₁ is provided in the slag water cooling tank 6 in the vicinity of the slag outlet side and the secondary cleaning waste water H ₁ in the slag water cleaning tank 9 is injected. The slag primary cleaning water nozzle 12 and the primary cleaning drain F ₁ from the slag water cooling tank 6 provided in the molten exhaust gas cooling chamber 5
It is a basic constitution of the invention that the water spray nozzle 18 for cooling the molten exhaust gas for injecting

Further, the method invention of the present application, in the waste melting treatment facility for producing granulated slag, the granulated slag D ₁ pulled up from the slag water cooling tank 6 is connected to the primary washing water nozzles 8 to 2
The granulated slag D is produced by injecting the next cleaning waste water H _1.
1 is first washed, and then the water granulated slag D ₁ discharged from the slag water cooling tank 6 is received in the slag water washing tank 9 and the water granulated slag D ₂ pulled up from the slag water washing tank 9
Fresh water E is sprayed from the next cleaning nozzle 11 to produce granulated slag D ₂
It is the basic constitution of the invention to carry out the secondary washing with fresh water E in a countercurrent manner.

[0013]

FIG. 1 shows an example of an embodiment of the present invention. In FIG. 1, 1 is an incinerator for garbage,
2 is an incinerator exhaust gas cooling chamber, 3 is a melting furnace for incinerated ash, 4 is an air preheater, 5 is a molten exhaust gas cooling chamber, 6 is a slag water cooling tank,
7 is a slag conveyor, 8 is a slag primary cleaning water nozzle, 9
Is a slag washing tank, 10 is a washing conveyor, 11 is a slag 2
Secondary cleaning water nozzle, 12 slag secondary cleaning drainage tank, 13 slag primary cleaning drainage pump, 14 slag primary cleaning drainage settling tank, 15 slag primary cleaning drainage tank, 16 slag primary cleaning drainage pump Reference numeral 17 is a water injection nozzle for cooling incineration exhaust gas, 18 is a water injection nozzle for cooling molten exhaust gas, and 19 is a sludge dehydrator.

Referring to FIG. 1, the waste A supplied into the waste incinerator 1 is incinerated here, and its exhaust gas is discharged to an exhaust gas cooling chamber 2, a waste recovery boiler, an exhaust gas treatment device, a chimney (not shown), etc. After that, it is released into the atmosphere. On the other hand, incinerator 1
Incineration ash (combustion residue) B from the
It is heated and melted here. Further, the exhaust gas from the melting furnace 3 is discharged into the atmosphere through the air preheater 4, the exhaust gas cooling chamber 5, the exhaust gas treatment device, the chimney (not shown) and the like.

Molten slag C formed in the melting furnace 3
Is dropped into the slag water cooling tank 6 filled with water through the outlet 3a, and becomes the granulated slag D ₁ here, and is then carried up onto the water surface by the slag conveyor 7 provided in the water cooling tank 6. In addition, a water cooling tank 6 is provided on the outer surface of the granulated slag D _1.
Slag cooling water F contaminated with heavy metals inside is 3-5w
Adhered at a rate of t%. Therefore, at the position where the wash slag D ₁ near the top of the slag conveyor 7 is exposed above the water surface, the water (2
This is washed with the next washing wastewater H ₁ ) and granulated slag D
_The contaminated slag cooling water F adhering to the outer surface of ₁ is washed off.

The granulated slag D ₁ obtained by washing off most of the slag cooling water F adhering to the surface by the water washing treatment is
Then, it is thrown into the slag washing tank 9 provided below it. The slag water washing tank 9 has a lower part as a water tank and an inclined cylindrical body is provided above the water tank, and a screw conveyor type washing conveyor 10 is provided in the inclined cylindrical body portion.
Is arranged. That is, the water granulated slag D ₁ dropped into the lower water tank of the slag water washing tank 9 is conveyed from the secondary washing nozzle 11 provided at the uppermost portion of the slag water washing tank 9 while being carried upward by the water washing conveyor 10. It is rewashed with fresh fresh water E, which completely rinses off the adhered dirty water on the surface remaining in the primary washing of the previous stage. This total 2
By the step water cleaning treatment, the granulated slag D ₂ becomes a high quality slag that does not cause heavy metal contamination and can be effectively used for various purposes.

The secondary washing water H used for the secondary washing of the granulated slag D ₁ in the slag washing tank 9 contains secondary water from the slag washing tank 9 in a form containing adhering water slightly contaminated with heavy metals. It flows down to the cleaning drainage tank 12 and is stored here.
The secondary cleaning waste water H ₁ stored in 2 is sent to the primary cleaning nozzle 8 by the primary cleaning water pump 13 and jetted downward from the top of the slag water cleaning tank 9 as primary cleaning water. It Further, the injected primary cleaning water is granulated slag D ₁
The slag water cooling tank 6 accumulates in the lower part of the melting furnace 3 while cleaning
Is used as the cooling water F for the molten slag C.

The cooling water F in the slag water cooling tank 6 is made of heavy metal because it is used for cooling the molten slag C after the fresh water E is countercurrently used for washing the water granulated slag in two steps. The degree of pollution increases. Therefore, in this embodiment, the same amount of contaminated slag cooling water F as the fresh water E supplied as the secondary washing water is drawn from the slag water cooling tank 6 to the settling tank 14, where it is separated into a supernatant and a settling sludge. It is configured. The supernatant liquid (primary washing drainage) F ₁ separated in the settling tank 14 is stored in the primary washing drainage tank 15 and then injected for cooling the incineration exhaust gas cooling chamber 2 and the molten exhaust gas cooling chamber 5. Primary wash drain pump 1 for use as water
6, water injection nozzle 17 and water injection nozzle 1 respectively
8 is supplied. The sludge J settled in the lower part of the settling tank 14 is dehydrated by the dehydrator 19, the cake J ₁ is fed into the melting furnace 3 again, and the desorbed liquid K is sent to wastewater treatment (not shown).

In the conventional production of water granulated slag in the melting furnace, once the slag cooling water F was filled with the slag cooling water F once, the amount of pollution caused by evaporation and the degree of pollution increased significantly. It is sufficient to replenish only the amount necessary for time replacement, and the required supply amount of the slag cooling water F may be relatively small. On the other hand, in the present invention, since it is necessary to constantly supply the fresh water E for cleaning, the amount of water used increases when it is limited to the slag cooling water F. However, in the conventional melting furnace, a large amount of fresh water is required to inject water into the exhaust gas cooling chamber 5, whereas in the present invention, as described above, the secondary cleaning water H and the primary cleaning water H ₁ Also, since the fresh water E that has been used as the slag cooling water F is injected as the cooling water for the exhaust gas cooling chamber 5, the mass balance of water does not increase as compared with the conventional melting furnace.

[0020]

[Table 1]

Table 1 shows the slag washing tank 6 with the injection from the primary cleaning nozzle 8 and the secondary cleaning nozzle 11 stopped.
Granulated slag (Sample 1) pulled up from the above (that is, granulated slag produced in the conventional melting furnace) and the primary cleaning nozzle 8
And a heavy metal with the washing slag (Sample 2) (that is, the granulated slag D ₂ subjected to the two-stage washing according to the present invention) taken out from above the slag washing tank 9 in a state where water is jetted from the secondary washing nozzle 11. The results of the dissolution test are shown.
Samples 1 and 2 are each about 1 from the first slag of molten slag C in the melting furnace 2 having a melting amount of 200 kg / H.
Granulated slag collected at the upper part of the slag conveyor 7 and the outlet of the water washing conveyor 10 after 0 hours,
The dissolution test for heavy metals was carried out according to the method specified in Environmental Agency Notification No. 46 Dissolution Test Method. Further, the amount of water discharged from each of the cleaning nozzles 8 and 11 when collecting the sample 2 is 20 l / mi for the primary cleaning nozzle 8 and 20 l / mi for the secondary cleaning nozzle 11 and the granulated slag D ₁
The average cleaning time on the slag conveyor 37 is about 6
The average washing time of the water granulated slag D _{2 on} the washing conveyor 10 was about 3 minutes.

As is clear from Table 1 above, the granulated slag D ₂ (Sample 2) produced by using the present invention is as follows:
All of them are completely below the elution value of heavy metals specified in the soil environmental standards, and it can be seen that they are extremely safe. Further, from the results in Table 1 above, by washing away the contaminated water adhering to the water granulated slag with clean water, the elution value of heavy metals decreases below the regulation value and the heavy metal from the inside of the water granulated slag itself is removed. It can be seen that there is no elution.

In the embodiment shown in FIG. 1, a stoker type incinerator is used as the incinerator 1, but the incinerator itself may be a fluidized bed type or a rotary kiln. It may be of the formula. Similarly, the melting furnace 3 may also be an electric energy type furnace or a fossil fuel combustion type furnace, and, for example, dry distillation pyrolysis in which incineration and melting are integrated. A melting method may be used. Further, the material to be melted may be fly ash or the waste itself as well as the combustion residue of municipal waste and various industrial wastes.

Further, in the embodiment shown in FIG. 1, the granulated slag is so-called counter-flow type which is cleaned in two stages.
This is because it was possible to almost completely and economically clean the contaminated water adhering to the surface of the granulated slag by the two-step cleaning, and the number of cleaning steps could be increased if necessary. The cleaning method can be a so-called parallel flow method.

[0025]

According to the present invention, at the end of the slag conveyor 7 provided in the slag water cooling tank 6, the water granulated slag pulled up from the water cooling tank 6 by the water sprayed from the primary cleaning nozzle 1 Subsequent washing, and further, the granulated slag subjected to the primary washing is discharged into the slag washing tank 9 equipped with the washing conveyor 10 and washed by the washing conveyor 10 and provided at the end of the washing conveyor 10. The secondary cleaning nozzle 11 sprays clean water to secondary clean the cleaning slag. As a result, the heavy metal contaminated water in the slag water cooling tank 6 adhering to the outer surface of the washed slag is completely washed away, and there is absolutely no risk of causing environmental pollution. ₂ can be generated relatively economically, and it becomes possible to further promote the effective use of granulated slag.

Further, in the present invention, the supplied fresh water E
Is used for three times as secondary cleaning water, primary cleaning water and slag cooling water, and part of the slag cooling water is injected as cooling water into the exhaust gas cooling chamber of the refuse incinerator or melting furnace. . As a result, most of the supplied fresh water E is effectively used, and there is no increase in the amount of water used as the entire waste melting treatment facility. INDUSTRIAL APPLICABILITY As described above, the present invention is capable of stably producing water granulated slag that is safe and of high quality without impairing the economical efficiency of operation management of the entire facility, and exhibits excellent practical utility. is there.

[Brief description of drawings]

FIG. 1 is an overall system diagram of a waste melting treatment facility equipped with a slag cleaning device showing an embodiment of the present invention.

FIG. 2 is a schematic explanatory view showing generation of water granulated slag in a conventional melting furnace.

[Explanation of symbols]

A: Garbage, B: Combustion residue, C: Molten slag, D ₁ ~
D ₃ : Granulated slag, E: Fresh water, F: Slag cooling water,
F ₁ : primary cleaning waste water, H: secondary cleaning water, H ₁ : primary cleaning water, J: separated sludge, J ₁ : dehydrated cake, K: desorption liquid,
1: incinerator, 2: incinerator exhaust gas cooling chamber, 3: melting furnace, 3
a: outlet, 4: air preheater, 5: molten exhaust gas cooling chamber,
6: Slag water cooling tank, 7: Slag conveyor, 8: Slag 1
Next washing water nozzle, 9: Slag washing tank, 10: Washing conveyor, 11: Slag secondary washing water nozzle, 12: Slag secondary washing drainage tank, 13: Slag primary washing water pump, 14: Slag primary washing drainage Sedimentation tank, 15: Slag primary cleaning drainage tank, 16: Slag primary cleaning drainage pump, 17: Water injection nozzle for cooling incineration exhaust gas, 18: Water spray nozzle for cooling molten exhaust gas, 19: Sludge dehydrator.

Claims (4)

[Claims] 1. A slag water cooling tank (6) having a slag conveyor (10) for receiving molten slag (C) in a waste melting treatment facility for producing water granulated slag, and from the slag water cooling tank (6). A slag washing tank (9) having a washing conveyor (10) for receiving the water granulated slag (D ₁ ),
A slag secondary washing water nozzle (1) provided near the slag outlet side of the slag washing tank (9) for injecting fresh water (E)
1) and a slag primary cleaning water nozzle (12) which is provided near the slag outlet side of the slag water cooling tank (6) and injects secondary cleaning drainage (H ₁ ) from the slag water cleaning tank (9).
And a molten-exhaust gas cooling water spray nozzle (18) which is provided in the molten-exhaust gas cooling chamber (5) and injects the primary cleaning wastewater (F ₁ ) from the slag water cooling tank (6). Waste melting treatment equipment equipped with a slag cleaning device. 2. The waste melting treatment facility comprises an incinerator (1) and a melting furnace (3), and the primary washing wastewater (F ₁ ) drawn from the slag water cooling tank (6) is precipitated and separated. Then, the supernatant liquid is used as exhaust gas cooling water for melting exhaust gas cooling water spray nozzle (18) and incineration exhaust gas cooling water spray nozzle (17) for incinerator exhaust gas cooling chamber (2) of incinerator (1).
A waste melting treatment facility equipped with the slag cleaning device according to claim 1, which is configured to be supplied to the waste melting treatment facility. 3. In a waste melting treatment facility for producing granulated slag, the granulated slag (D ₁ ) pulled up from the slag water cooling tank (6) is supplied with primary cleaning water from a primary cleaning water nozzle (8). the slag by (H ₁₎ for injecting (D ₁₎
Washed primary and then the conjunction accepting slag water-cooled tank granulated slag discharged from (6) (D ₁₎ to the slag washing tank (9) in, granulated slag was pulled from the slag washing tank (9) Fresh water (E) is sprayed from ( ₂ ) to the secondary cleaning nozzle (11) to carry out secondary cleaning of the granulated slag (D ₂ ) with fresh water (E) in a countercurrent manner, and at the same time, a slag washing tank (9)
A method for producing granulated slag, characterized in that the waste water from the water is used as the primary washing water (H ₁ ). 4. The primary cleaning waste water (F ₁ ) drawn from the slag water cooling tank (6) is used as injection water for cooling exhaust gas of a melting furnace (3) and / or an incinerator (1) forming a melting treatment facility. The method for producing granulated slag according to claim 3, wherein the method is performed.