JP2002168417A - Facilities and method for treating waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the facilities and method for treating waste that can treat the waste without using a large amount of raw materials such as oxygen and coke and with simple facilities. SOLUTION: Facilities having a melting chamber 1 and a spare chamber 2 that is directly connected to the upper portion of the melting chamber 1 are used, a melt 8 is formed in the melting chamber 1 and at the same time the melt 8 is heated by arc 7 that is generated by an arc electrode 6, the waste 3 is continuously or discontinuously loaded into the spare chamber 2, the waste 3 is thermally decomposed or burned until it reaches the chamber 1, the combustible content is gasified and at the same time a metal constituent out of the incombustible contents is melted by the melt 8 in the chamber 1, and the other constituents are formed into slag by the melt 8 in the chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a facility and a method for treating waste such as municipal waste and industrial waste.

[0002]

2. Description of the Related Art In recent years, in the treatment of waste such as municipal solid waste and industrial waste, no harmful substances such as dioxins are produced (no pollution), and the amount of residual substances after treatment is reduced as much as possible. (Reduction in volume), and recovery and effective use of energy remaining in waste (recycling) are required.

[0003] As a waste treatment technique that satisfies such demands, a direct melting method for directly melting waste in a vertical furnace has been developed (Japanese Patent Laid-Open No. 52-24790, etc.).
In this technology, waste is put into a vertical furnace together with coke, limestone, etc., and oxygen is blown from the bottom of the furnace,
The waste is thermally decomposed to gasify combustibles, and the incombustibles are turned into slag by the heat of combustion of coke and the injected oxygen. Further, the metal contained in the non-combustible components is melted. On the other hand, the gas generated by the thermal decomposition is partially burned by the blowing gas in the upper space of the furnace to form a high-temperature reducing atmosphere of 1000 ° C., thereby preventing tar from being generated and making it difficult to generate dioxins. The exhaust gas is completely combusted in a secondary combustion chamber boiler provided thereafter, heat is recovered from high-temperature gas, and then rapidly cooled and collected by a dust collector.

[0004]

However, the direct melting method using such a vertical furnace has the following problems to be solved.

That is, the ash and metal generated by the combustion and thermal decomposition of waste are melted by the heat of combustion of coke and oxygen to form slag and molten metal, so that large amounts of oxygen and coke are used, Equipment (oxygen production equipment, coke injection equipment, etc.) are also required.
Since there is also ash from coke, the amount of lime for adjusting the slag component must of course be large.

Further, since the heat of combustion of coke and oxygen is used, the final exhaust gas after secondary combustion has a large amount of sensible heat, so gas recovery is indispensable to reduce the total cost. The installation of power generation equipment and the like becomes indispensable, and the equipment cost must be high. This presents a particular obstacle to the disposal of metal-rich waste.

The present invention has been made in view of the above circumstances, and has a waste treatment facility and a waste treatment facility capable of treating waste with a simple facility without using a large amount of raw materials such as oxygen and coke. The aim is to provide a method.

[0008]

In order to solve the above-mentioned problems, the present invention provides a melting chamber, a heating means for melting a metal charged in the melting chamber and heating a formed molten metal, A preliminary chamber directly connected to the upper part of the melting chamber, and a waste loading means for continuously or intermittently loading waste into the preliminary chamber, wherein the waste loaded into the preliminary chamber is Pyrolysis or combustion up to the melting chamber,
The waste treatment is characterized in that the combustible component is gasified and the metal component of the non-combustible component is dissolved in the molten metal in the melting chamber, and other components are slagged by the molten metal in the melting chamber. Provide equipment.

Further, the present invention uses equipment provided with a melting chamber and a preliminary chamber directly connected to an upper part thereof, and forms molten metal in the melting chamber and heats the molten metal in the preliminary chamber while heating the molten metal. The waste is charged continuously or intermittently, and the waste is thermally decomposed or burned until it reaches the melting chamber, the combustible content is gasified, and the metal component of the non-combustible content is contained in the melting chamber. Dissolved in molten metal,
The present invention provides a method for treating waste, wherein other components are slagged by molten metal in the melting chamber.

According to the present invention, molten metal is stored in the melting chamber using equipment equipped with a melting chamber and a preliminary chamber directly connected to the melting chamber, and waste is supplied to the melting chamber via the preliminary chamber. Waste is pyrolyzed or burned mainly in the spare room,
While gasifying the combustibles, the metal components of the non-combustibles are dissolved by the molten metal in the melting chamber, and the other components are slagged by the molten metal in the melting chamber. Since incombustibles are melted by the sensible heat of the molten metal heated by the heating means, coke and lime need only be used for adjusting the components of slag, and large-scale use is unnecessary. Basically, it can be performed with air or the like entering the melting chamber, and a large amount of oxygen is not required. Therefore, the sensible heat of the final exhaust gas after the secondary combustion is small, and there is no need to perform gas recovery. Therefore, equipment such as a boiler is unnecessary, and waste can be treated with simple equipment.

In the present invention, by providing an oxygen-containing gas inlet port in the melting chamber and / or the preliminary chamber to introduce an oxygen-containing gas such as air, the thermal decomposition or combustion of waste can be assisted, and the melting chamber and / or Alternatively, the unburned gas can be burned in the spare chamber.

Further, by providing a quenching device for quenching combustion exhaust gas from the melting chamber and the preliminary chamber, high-temperature combustion gas can be quenched, and generation of aromatic chlorine compounds represented by dioxin and white smoke can be prevented. -The generation of offensive odor can be effectively prevented.

Further, a combustion chamber is provided in the preceding stage of the quenching equipment to burn the unburned portion of the combustion exhaust gas from the melting chamber and the preparatory chamber, so that the temperature of the exhaust gas can be further increased, and is represented by dioxin. Generation of aromatic chlorine compounds and the like, and generation of white smoke and offensive odor can be more effectively prevented. In this case, combustion can be further promoted by adding auxiliary fuel in the combustion chamber,
The generation of dioxins can be more effectively prevented.

Further, by blowing oxygen into the molten metal by the oxygen gas blowing means, the heating of the molten metal can be assisted. Further, by supplying the carbon material into the melting chamber by the carbon material supply means, CO can be generated by the reaction with oxygen to assist the heating of the molten metal.

It is preferable that an arc electrode is used as the heating means, and the molten metal is heated by an arc formed between the arc electrode and the molten metal. This allows
The molten metal can be heated with the same equipment as a normal arc furnace.

Furthermore, it is preferable to use molten iron as the molten metal. Molten iron is economical because it is easy to obtain, such as iron scrap, and can be obtained from inexpensive raw materials. Since the temperature is high, the combustion gas can be heated to a high temperature.
It is possible to reliably prevent the generation of dioxins and the like.

Incidentally, Japanese Patent Application Laid-Open No. 5-116441 discloses that
A method is disclosed in which shredder dust is charged together with iron scrap into an electric furnace and incinerated, but this method is not a furnace dedicated to treating shredder dust, but mainly melts scrap. It is different from a furnace that exclusively processes waste as in the invention.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing a waste treatment facility according to one embodiment of the present invention. This waste treatment facility includes a dissolution chamber 1 and a shaft-shaped preliminary chamber 2 directly connected to one side above the dissolution chamber. At the upper end of the preliminary chamber 2, an exhaust unit 2a connected to an exhaust gas treatment system described later is provided. In addition, an opening / closing lid 2b is provided in an upper part of the preliminary chamber 2. Above the preliminary chamber 2, a waste storage container 40 is provided.

An openable / closable lid 5 is provided at the upper part of the melting chamber 1, and an arc electrode 6 is inserted vertically through the lid 5 from above the melting chamber 1. Further, at a position facing the arc electrode 6 on the bottom portion 10 of the melting chamber 1,
A bottom electrode 11 is provided.

In the melting chamber 1, the lid 5 is opened, and a cold iron source such as iron scrap is previously charged by appropriate means. The cold iron source is melted by the arc 7 formed by the arc electrode 6. It becomes molten metal 8. A slag 9 is formed on the molten metal 8, and the arc 7 is formed in the slag 9.

In the melting chamber 1, two lances 12a,
12b is inserted with its tip facing the molten steel surface,
Oxygen is supplied from the lance 12a, and a carbon material, for example, coke as an auxiliary heat source is injected from the lance 12b.

A tap hole 14 is formed at the bottom of a protruding portion 1a provided at a portion different from the side where the preliminary chamber 2 of the melting chamber 1 is directly connected, and a slag door 15 is provided at a side end thereof. ing.

From the above-mentioned waste storage container 40, metal components such as iron, copper, aluminum, etc., such as municipal waste, waste home appliances, industrial waste, incinerated ash, excavated waste from final disposal sites, shredder dust, waste plastic, etc. Of various kinds of waste 3, such as those containing a large amount of metal, those containing a very small amount of metal, or those containing no metal at all, are continuously or intermittently supplied by a waste supply mechanism 41 having an appropriate structure. Will be charged. In the range from the molten metal position in the melting chamber 1 to the upper end position of the preliminary chamber 2, the lid 5 and the side wall of the melting chamber 1 and the side wall of the preliminary chamber 2 are provided with a plurality of air inlets for introducing air into the waste loading portion. Are provided.
The combustibles in the waste 3 are thermally decomposed by the heat of the high-temperature molten metal 8 existing in the melting chamber 1, and the air entering the melting chamber 1 and the air inlets provided in the melting chamber 1 and the preliminary chamber 2. The ash and metal remaining after being partially burned by the air introduced from 16 reach the melting chamber 1 in a fluidized state. Then, in the melting chamber 1, the ash is slagged by the heat of the molten metal 8 heated to a high temperature by the arc 7 and becomes a part of the slag 9 on the molten metal 8. Further, the metal component dissolves in the molten metal. In some cases, limestone and coke may be charged together with the waste or directly into the melting chamber for adjusting the components of the generated slag.

The flammable gas generated by the pyrolysis of the combustible components in the waste 3 is burned by the air from the air inlet 16.
In this case, by adjusting the position of the air inlet 16 and the amount of air to be supplied, the flammable gas can be present up to the upper part of the preliminary chamber 2. By burning the unburned portion with the air from the air inlet 16 in the space, the temperature of the exhaust gas in the vicinity of the outlet of the preliminary chamber 2, that is, in the exhaust portion 2a can be controlled to a high temperature.

An exhaust gas treatment system 20 is connected to the exhaust section 2a of the preliminary chamber 2. The exhaust gas treatment system 20 has a gas cooling tower 21. As described above, the exhaust gas is rapidly cooled to generate harmful substances such as an aromatic chlorine compound represented by dioxin, and to generate white smoke and odor. Can be prevented. An adsorbent supply unit 22 is provided downstream of the gas cooling tower 21, and by supplying the adsorbent to the exhaust gas therefrom, harmful substances can be further reduced to a low level. In this case, slaked lime, activated carbon, coal ash and the like can be used as the adsorbent, and these can be supplied by spraying them onto the exhaust gas. Further, the exhaust gas reaches the stack 24 via the bag filter 23 and is discharged to the atmosphere. Reference numeral 25 denotes a blower.

In the waste treatment equipment thus constructed, first, a cold iron source such as iron scrap is charged into the melting chamber 1, an arc 7 is formed by the arc electrode 6, and the cold iron source is melted. . At this time, oxygen is supplied by the lance 12a to assist dissolution of the cold iron source. When the molten metal 8 accumulates in the furnace, coke as an auxiliary heat source is injected into the slag from the lance 12b to shift to a slag forming operation, and the tip of the arc electrode 6 is buried in the slag 9 so that the arc 7 9. The coke as the auxiliary heat source burns with the supplied oxygen and contributes to the dissolution of the cold iron source.

In this state, the waste 3 is continuously or intermittently charged from the waste storage container 40 into the preliminary chamber 2 by the waste supply mechanism 41. In the preliminary chamber 2, the waste 3 is thermally decomposed by the heat of the high-temperature molten metal 8 existing in the melting chamber 1, and partially due to air entering the melting chamber 1 and air introduced from the air inlet 16. Burned,
The remaining ash and metal reach the melting chamber 1 in a fluidized state. Then, in the melting chamber 1, slag is formed by the heat of the molten metal 8 heated to a high temperature by the arc 7 and becomes a part of the slag 9 on the molten metal 8. Further, the metal component dissolves in the molten metal 8. When the slag 9 has accumulated in a certain amount or more, the slag door 15 is opened and the slag is discharged.
In the case of treating waste containing a large amount of metal, the molten metal 8 is discharged from the tap hole 14 when a certain amount of the molten metal 8 has accumulated.

On the other hand, the flammable gas generated by the pyrolysis of the combustible components in the waste 3 is generated by the air from the air inlet 16.
Combustion can be performed mainly in the upper space of the preliminary chamber 2, whereby the temperature of the exhaust gas in the vicinity of the outlet, that is, in the exhaust part 2a can be controlled to a high temperature.

Since the exhaust gas can be controlled to a high temperature in this way, the exhaust gas is then rapidly cooled in the gas cooling tower 21 of the exhaust gas treatment system 20 to reduce harmful substances such as aromatic chlorine compounds represented by dioxin. Generation and generation of white smoke and odor can be prevented.

From the viewpoint of effectively preventing the generation of such harmful substances, the temperature of the exhaust gas in the vicinity of the outlet of the preparatory chamber 2 is preferably set to 750 ° C. or more at which decomposition thereof is promoted, and more preferably to 900 ° C. or more. More preferably,

The exhaust gas discharged from the exhaust part 2 a of the preliminary chamber 2 is sucked by the blower 25 in the exhaust gas treatment system 20 and first reaches the gas cooling tower 21. Here, the exhaust gas is rapidly cooled, and as described above, harmful substances such as dioxin,
Prevents generation of white smoke and odor. Next, the adsorbent supply unit 2
By supplying the adsorbent to the exhaust gas from 2, the harmful substances in the exhaust gas are further reduced to a low level. Further, the exhaust gas reaches the stack 24 via the bag filter 23 and is discharged to the atmosphere.

In some cases, the combustible gas is not completely burned in the upper space of the preliminary chamber 2. In such a case, a secondary combustion chamber 26 as shown in FIG. The air may be introduced from the air inlet 27 and secondary combustion of the combustible gas may be performed. When it is desired to further increase the exhaust gas temperature, an auxiliary fuel supply port 28 for supplying auxiliary fuel such as oil to the secondary combustion chamber 26 may be provided to burn the auxiliary fuel as shown in FIG.

As described above, in the present embodiment, the melting chamber 1
And a preparatory chamber 2 directly connected to the upper portion thereof, and the molten metal 8 is stored in the melting chamber 1, and the waste 3 is supplied to the melting chamber 1 through the preparatory chamber 2. It is mainly pyrolyzed or burned in the prechamber 2 to gasify its combustible components, dissolve the metal component of the non-combustible components in the molten metal 8, and slag the other components with the molten metal 8. As described above, since the non-combustible portion of the waste is melted by the sensible heat of the molten metal 8 heated by the arc, coke and lime may be used only for adjusting the components of the slag, and a large amount of use is unnecessary. Pyrolysis or combustion of can basically be performed with invading air and does not require the use of large amounts of oxygen. Therefore, the sensible heat of the final exhaust gas is small, and there is no need to recover the gas. Therefore, equipment such as a boiler is unnecessary, and the waste can be treated with simple equipment. In addition, since the exhaust gas temperature can be increased, quenching by the gas cooling tower 21 can prevent generation of harmful substances such as aromatic chlorine compounds represented by dioxin, and generation of white smoke and malodor. . Furthermore, the slag finally generated can be effectively used, and the molten metal in the melting chamber 1 can be used repeatedly without being discharged.

The present invention can be variously modified without being limited to the above embodiment. For example, in the above embodiment, molten iron is used as the molten metal, but the present invention is not limited to this, and other metals may be used. Although the air inlet 16 was provided,
Not only air but also other oxygen-containing gas, for example, oxygen gas may be introduced. In addition, although such an inlet is provided in both the dissolution chamber and the spare chamber, it is not necessarily provided in both, and may be provided in either one. Furthermore, if the intruding air is sufficient, the air inlet is not necessarily required. Furthermore, the arc electrode is used as a means for heating the molten metal, but the present invention is not limited to this. For example, another heating means such as an oxygen burner may be used.

[0035]

Embodiments of the present invention will be described below. [Embodiment 1] The structure shown in FIG. 1 is used. Further, as shown in FIG.
6 was used to treat shredder dust as waste 3. First, 30 tons of iron scrap was charged into the melting chamber 1 (furnace diameter 6.5 m, height 3.5 m), and an arc was generated by the arc electrode 6 (diameter 24 inch graphite electrode) at a maximum power supply capacity of 550 V and 80 kA. After forming and melting the iron scrap in the melting chamber 1,
(2.7 m wide, 4.5 m long, 6 m high) scrap car shredder dust (CS) having the average composition shown in Table 1.
D) was intermittently fed into the preparatory chamber 2 at a feed rate of 5 t / h by a charging bucket at intervals of approximately 10 minutes at a rate of 500 kg / times. Further, as the ash in the CSD turned into slag, lime was added for adjusting its components. Also, a small amount of coke was added for slag adjustment.

[0036]

[Table 1]

After the start of CSD injection, 250 V, 13 kA
And the arc heating of the molten metal was continued. In addition, a total of 260 Nm ³ / min of air is introduced into the melting chamber 1 and the preliminary chamber 2 from the two locations in the melting chamber 1 and the air inlets 16 provided at three horizontal cross sections of the preliminary chamber 2 × 2 stages. I blew it. Further, air of 340 Nm ³ / min is blown into the secondary combustion chamber 26 (about 4 m diameter, height 14 m) for combustion and dilution, and 18 at the gas cooling tower 21 (about 4 m diameter, height 14 m).
m ³ / h of water was sprayed from above. Further, the exhaust gas after leaving the gas cooling tower 21 was diluted by introducing air of about 500 Nm ³ / min, and the temperature was lowered. Spare room 2 when CSD processing was performed under the above conditions
Table 2 shows the outlet, the secondary combustion chamber 26 outlet, the gas cooling tower 21 outlet, and the exhaust gas flow rate, composition, and temperature after introduction of the dilution air. Since the composition of the CSD varies, the composition and temperature of the exhaust gas naturally vary.
Table 2 shows the average values.

[0038]

[Table 2]

By performing the above CSD processing continuously for 12 hours, about 60 tons of CSD could be processed. The power consumption required at this time is 61
3 kWh / t CSD and lime intensity is 35 kg / t
CSD. Further, the analytical value of dioxin at the outlet of the dust collector during this continuous treatment was 0.05 ng TEQ.
/ Nm ³ , which is a value that has no problem at all.

In about 30 tons of molten metal remaining in the melting chamber 1 after continuous treatment for 12 hours, Cu in the CSD was concentrated to about 10%. The ash in the CSD was turned into slag, and about 30 tons of slag was formed on the molten metal.

From the above results, according to the present invention, oxygen,
It was confirmed that waste could be treated without using harmful substances with a simple facility without using a large amount of raw materials such as coke.

[0042]

As described above, according to the present invention,
Using equipment equipped with a melting chamber and a preparatory chamber directly connected above, storing the molten metal in the melting chamber, supplying waste to the melting chamber through the preparatory chamber, and mainly discharging the waste into the preparatory chamber In the thermal decomposition or combustion, the combustibles are gasified and the metal components of the incombustibles are dissolved by the molten metal in the melting chamber, and the other components are slagged by the molten metal in the melting chamber. As described above, the incombustible portion of waste is melted by the sensible heat of the molten metal heated by the heating means, so that coke and lime can be used for adjusting the components of slag, and large-scale use is unnecessary. Pyrolysis or combustion of can basically be performed with invading air,
Large amounts of oxygen are not required. Therefore, the sensible heat of the final exhaust gas after the secondary combustion is small, and there is no need to perform gas recovery. Therefore, equipment such as a boiler is unnecessary, and waste can be treated with simple equipment.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a waste treatment facility according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a waste treatment facility according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view for explaining a modification of the waste treatment facility shown in FIG. 2;

[Explanation of symbols]

 1; melting chamber 2; preparatory chamber 3; waste 6; arc electrode 7; arc 8; molten metal 9; slag 12a; oxygen lance 12b; coke lance 15; slag door 16; Tower 26; secondary combustion chamber 40; waste storage container 41; waste supply mechanism

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22B 7/00 F23G 5/16 ZABE 4D004 F23G 5/16 ZAB 5/44 ZABZ 4K001 5/44 ZAB F27B 3 / 08 4K014 F23J 15/06 3/18 4K045 15/00 3/22 4K056 F27B 3/08 F27D 17/00 104A 3/18 H05B 7/18 3/22 B09B 3/00 303K F27D 17/00 104 303J H05B 7 / 18 F23J 15/00 KJZ (72) Inventor Toshimichi Maki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kokan Co., Ltd. (72) Inventor Tsuyoshi Nakayama 1-1-2, Marunouchi, Chiyoda-ku, Tokyo F-term (reference) in Nippon Kokan Co., Ltd. 3K061 DA19 DB01 DB16 3K065 GA03 GA13 GA21 GA32 3K070 DA01 DA04 DA0 5 DA24 DA32. RB24 4K056 AA05 BA02 BB08 CA01 CA20 DB03 DB07

Claims (14)

[Claims] 1. A melting chamber, a heating means for melting the metal charged in the melting chamber and heating the formed molten metal, a preliminary chamber directly connected above the melting chamber, and Waste charging means for continuously or intermittently charging the waste, wherein the waste charged in the preliminary chamber is thermally decomposed or burned until reaching the melting chamber, and its flammable Waste is gasified and a metal component of the non-combustible component is dissolved in the molten metal in the melting chamber, and other components are slagged by the molten metal in the melting chamber. 2. The waste treatment facility according to claim 1, wherein the melting chamber and / or the preliminary chamber have an oxygen-containing gas inlet for introducing an oxygen-containing gas. 3. The waste treatment equipment according to claim 1, further comprising a quenching equipment for quenching combustion exhaust gas from the melting chamber and the preliminary chamber. 4. The disposal according to claim 3, further comprising a combustion chamber provided before the quenching facility and configured to burn an unburned portion of the combustion exhaust gas from the melting chamber and the preliminary chamber. Equipment for processing objects. 5. The waste treatment facility according to claim 1, further comprising oxygen gas blowing means for blowing oxygen gas into the melting chamber. 6. The waste treatment facility according to claim 1, further comprising a carbon material supply means for supplying a carbon material into the melting chamber. 7. The apparatus according to claim 1, wherein the heating means has an arc electrode, and heats the molten metal by an arc formed between the arc electrode and the molten metal. A waste treatment facility according to claim 1. 8. Using a facility having a melting chamber and a spare chamber directly connected to the upper part thereof, forming molten metal in the melting chamber and heating the molten metal while continuously discharging waste in the spare chamber. The waste is pyrolyzed or burned until it reaches the melting chamber to gasify the combustibles, and the metal component of the non-combustibles is dissolved in the molten metal in the melting chamber. Wherein the other components are slagged by the molten metal in the melting chamber. 9. The method for treating waste according to claim 8, wherein an oxygen-containing gas is supplied to the melting chamber and / or the preliminary chamber to incinerate the waste. 10. The method according to claim 8, wherein the combustion exhaust gas from the melting chamber and the preliminary chamber is rapidly cooled. 11. The method for treating waste according to claim 10, wherein an unburned portion of the combustion exhaust gas from the melting chamber and the preliminary chamber is burned before the quenching of the combustion exhaust gas. 12. The waste treatment method according to claim 8, wherein oxygen gas is blown into the melting chamber. 13. The method for treating waste according to claim 8, wherein a carbon material is supplied into the melting chamber. 14. The method for treating waste according to claim 8, wherein the heating of the molten metal is performed by arc heating.