JP4576156B2 - Waste treatment equipment that recovers thermal energy and valuable metals - Google Patents

Description

  The present invention relates to a waste treatment technique for treating shredder dust, ship bottom paint, and the like discharged from an abandoned automobile and the like without generating dioxin, and for recycling useful materials and recovering energy.

When incinerating waste such as ship bottom paint and shredder dust, it has been found that dioxins (hereinafter referred to as DXNs) are re-synthesized at low temperatures due to the catalytic reaction of metals (especially copper) contained in the waste. It is said that it is effective to collect dust containing metal oxides and salts at a high temperature. However, at present, a high-efficiency high-temperature dust collector is expensive and has not yet been put into practical use.

It has been found that by developing a high-efficiency high-temperature dust collector and sending clean exhaust gas without dust to a waste gas boiler on the downstream side, heat transfer efficiency can be improved and a high heat recovery rate can be obtained. Yes. Furthermore, it has been found that the burden on the high temperature corrosion of the metal material constituting the waste gas boiler can be reduced.
JP 2004-33855 A JP-A-10-165742 JP 2002-102647 A Noriaki Ishibashi "Study on the production of dioxins in waste incineration" Ritsumeikan University

In general, the synthesis of DXNs is extremely small because pyrolysis is performed at high temperatures in incinerators and pyrolysis furnaces. However, in such a process in which combustion exhaust gas is cooled, metals in dust (especially DXNs are supposed to be re-synthesized by the catalytic action. Under such circumstances, the removal of DXNs in the exhaust gas is carried out by the following method.
(1) A method of spraying an additive such as activated carbon to adsorb the DXNs and collecting them with a dust collector (2) A method of passing gas through a packed bed of activated carbon or the like and adsorbing and removing DXNs (3) Using a catalyst There are methods of decomposing and removing DXNs, all of which remove the produced DXNs and have the following drawbacks.
(B) Many equipments and complicated operations (b) High construction and running costs (c) Low energy recovery efficiency (d) Low removal rate of DXNs and limited adsorption ) Increases the amount of waste discharged (f) There is no method to detect the discharge status of DXNs in real time, so the on-site confirmation of the treatment effect cannot be performed.

Than that in this way, be dust collection at Atsushi Ko (6 00 ° C. C.) is not generating the DXN compound is effective as a method that does not re-synthesized, reasonable does not leave DXN of any kind in collecting dust It is. However, high-efficiency filters that can be used at temperatures exceeding 300 ° C. include ceramic fiber type and cordierite type or silicon carbide type, and the former has a low filtration area per unit area and is not heat-treated. Since its strength is low, it is difficult to use at 400 ° C. or higher, and the latter is expensive and unsuitable for normal industrial use.

In addition, metal heat exchangers used for waste treatment are difficult to use in the high temperature range of 700 ° C or higher due to dust welding and high temperature corrosion caused by alkali metals and chlorine. Generally, spraying water or introducing cooling air As a result, the heat recovery is performed by reducing the exhaust gas temperature to about 700 ° C., and the heat efficiency is poor.

As a result, thermal decomposition of waste (ASR and waste paint) containing chlorine and heavy metals has a problem in the production and resynthesis of DXNs. At present, gasification and melting are the mainstream. Dissemination of treatment is difficult due to soaring construction costs and running costs.

On the other hand, although an iron recycling system has been established, dust generated during steelmaking is collected for a fee by a zinc recovery manufacturer, where zinc is recovered, and the processing residue containing reduced iron is disposed of in landfills. . In addition, there are cases where detoxification / stabilization treatment is performed and all of them are landfilled. While it is difficult to secure a landfill site, effective recycling with good cost performance is also possible from the viewpoint of effective use of resources. There is an urgent need to establish a new method.

The invention of claim 1 according to the present application includes a silicon carbide heat exchanger, a high-temperature dust collector composed of a ceramic fiber filter, and a heat exchanger (hereinafter referred to as a heat exchanger) in a smoke exhaust section of a swirl combustion furnace having a cyclone structure inside. In some cases, high-temperature incineration can be performed by connecting the heat exchanger to the heat exchanger or connecting the exhaust fan via a dust collector .

In the invention of claim 2 according to the present application, a heat exchange pipe made of silicon carbide baked at a temperature of 1800 ° C. or higher is attached to the heat exchanger to make a heat exchanger that can withstand high temperatures, whereby fresh air is heated to high temperature And heated to the upstream swirl combustion furnace to prevent a decrease in the furnace temperature, thereby suppressing the generation of dioxins.

By blowing the high-temperature air that has passed through the ceramic heat exchanger as combustion air to the swirl combustion furnace, the temperature in the waste combustion furnace is always kept high. Therefore, the occurrence of DXNs is suppressed.

By improving the heat resistance by firing a filter made of ceramic fiber at 1000 ° C. or higher, it became possible to pass the exhaust gas from the swirl combustion furnace while maintaining a high temperature of 600 ° C. or higher. Therefore, the occurrence of DXNs is suppressed even during dust collection or heat exchange.

Generation of DXNs in the swirl combustion furnace is suppressed by co-firing waste and a reducing agent and forming a reducing atmosphere by a thermite reaction generated thereby. Moreover, it becomes possible to collect | recover metals with a different boiling point in a high temperature dust collector, an energy recovery machine, and the dust collector provided after that.

And coarse particles mainly composed of iron oxide, and fine and binary grade zinc oxide as a main component, the coarse refluxed under melting furnace, fine and zinc oxide by the energy, etc. recovery system Recycling of steelmaking dust was facilitated by means of concentration.

Incineration is the most efficient method for reducing ship bottom paint, shredder dust, etc. or steelmaking dust. The energy and valuable metal recovery system 1 (hereinafter sometimes referred to as the present system 1) of the present invention for recovering energy and active components without generating DXNs when these wastes are incinerated. A swirl combustion furnace 2 configured to generate a swirl flow in the furnace, a ceramic heat exchanger 3, a ceramic high-temperature dust collector 4, and a heat exchanger 5 are sequentially connected to the furnace, and further induced to the heat exchanger 5 In this configuration, the air blower 7 is connected to the induction fan 7 via the dust collector 6. Moreover, the heat exchanger 3 and the dust collector 4 are equipped with a heat exchange pipe made of ceramic and a dust collection filter fired at 1800 ° C. or higher in order to have heat resistance of 600 ° C. or higher. The high-temperature combustion exhaust gas is passed through the furnace 3 and the heat is recovered into fresh air sent from the blower 9 , and this air is blown in as a part of the swirling flow in the combustion furnace 2. The combustion exhaust gas whose temperature has fallen is configured such that the dust S is collected by the downstream dust collector 4 and then the heat energy is collected by a general-purpose heat exchanger.

Turning combustion furnace 2 of the can substantially at the center position, the upright cylinder 2b inner through the furnace bottom to near the ceiling of the furnace, the upper end of the inner cylinder 2b, the small diameter than that of the furnace wall 2a its base end a flue gas tube 2c is inserted in a state the upper end and slightly to overlap the inner cylinder 2b, the other end is connected to the heat exchanger 3 is passed through the ceiling of the combustion furnace 2. A combustion material input port 2d, an auxiliary combustion burner (not shown), and a blower 8 for forming a swirling airflow in the furnace are mounted on the side wall of the combustion furnace 2.

Into the hot heat exchanger 3 is that the housing 3b, a sintered silicon carbide-made heat exchange pipe 3c is attached a number composed of 1800 ° C. or higher, the combustion exhaust gas pipe for the heat exchanger passing through the housing 3b The heat exchanger exchanges heat with fresh air (outside air) A sent by the blower 9 into the pipe 3c in contact with the outer peripheral surface of 3c. The combustion exhaust gas cooled by this is introduced into the high-temperature dust collector 4 connected to the downstream side, and the fresh air A heated in one pipe 3c is sent to the blower path from the blower 8 through the blower pipe 3a. They are joined and connected to the combustion furnace 2 or to an independent swirling air forming air inlet (not shown) provided on the furnace wall.

The ceramic high-temperature dust collector 4 connected downstream of the heat exchanger 3 is shaped into a substantially test tube shape (or a hollow candle shape) with one opening therein, and is baked at a temperature of 1000 ° C. or higher. A silica-based ceramic filter 4a is attached. The opening of the filter 4a is airtightly connected so as to be sucked in by a suction exhaust fan 7 connected to the most downstream side via the heat exchanger 5. In addition, the ceramic filter 4a is provided with a blower 10 for sending the pulse air 4p at a certain time interval within the inner diameter, and the dust S adhering to the outer periphery of the ceramic filter 4c by the pulse air 4p is discharged to the discharge port. It is set as the structure which pays off from 4e.

A heat exchanger 5 is further connected downstream of the ceramic high-temperature dust collector 4. The combustion exhaust gas G passing through the heat exchanger 5 is not at a high temperature because the heat exchange has already been performed in the previous stage. Therefore, a heat exchanger having normal heat resistance is used.

In FIG. 1, a dust collector 6 is shown downstream of the heat exchanger 5. The dust collector 6 is used when the combustion exhaust gas is strongly acidic. For example, an acid gas treating agent is put into the dust collector 6 with a bag filter, and the exhaust gas is allowed to pass through the dust collector 6. It is going to be released into the atmosphere. Therefore, it is not essential.

An induction exhaust fan 7 is incorporated in the most downstream of each of the connected equipments, and exhaust gas discharged from the swirl combustion furnace 2 is sucked and released into the atmosphere. This induction fan 7 does not require any special specifications.

By the above-mentioned system, reduction extraction of metal was performed by incineration of waste ship bottom paint (Chinese Paint Co., Ltd. Sea Grand Prix 1000). This ship bottom paint contains 45% to 50% of copper (Cu). The incineration of this waste is carried out using the above-described swirl combustion furnace 2 with a furnace top temperature of 1000 ° C. and a flue gas outlet temperature of 950 ° C., introduced into the ceramic heat exchanger 3 to exchange heat with fresh air, and heated fresh Air is blown to the upstream swirl combustion furnace 2, and the exhaust gas is reduced to a temperature of about 600 ° C., enters the ceramic high-temperature dust collector 4, further decreases to about 400 ° C., and then the induced exhaust fan through the heat exchanger 6. 7 to the atmosphere.

This waste ship bottom paint is 6.05% Sea Grand Prix 1000, 5.075 Rabax (chlorinated rubber paint), 60.53% thinner, 20.99% water, 2.97% surfactant, 4. 37% (composition ratio) was designed and used. In the system of the present invention, 144 kg is used, and for comparison, a combustion system combining a swirl combustion furnace, a normal heat exchanger, and a dust collector is 60.8 kg. Incinerated. The results are shown in Table 1.

  Further, the copper and chlorine in the fly ash captured by the dust collector in the normal combustion furnace and the high temperature dust collector according to the present invention are Cu: 12.6%, Cl: 5.8%, and the latter is Cu: 21. 3%, Cl: 0.066%. As described above, the system 1 according to the present invention has a high metal recovery efficiency and an excellent effect of suppressing the generation of Cl.

The dust generated from the melting electric furnace during steelmaking contains approximately 50% iron (Fe) and 20% zinc (Zn). The system 1 of the present invention is used to separate iron and zinc. For this purpose, first, the steelmaking dust is finely pulverized by a dry method and classified by 10 μm by a dry method, and the coarse one is granulated and returned to the steelmaking step, assuming that the Zn content is about 6 to 7% or less. The remaining 10 μm or less contains 30% or more of Zn (Table 2), and this is burned in the swirl combustion furnace 1 of the present system. First, the inside of a furnace is made into a combustion state with an auxiliary burner, and the steelmaking dust is burned. Among these dusts, those having a high melting point settle to the furnace bottom during turning, and those having a low melting point become fine particles and are sucked into the induction fan 7 and captured as soot dust in the ceramic heat exchanger 3 and the ceramic dust collector 4. The The metal having a low melting point in the dust is Zn and can be easily recovered by heating and melting it. Further, the metal settled on the bottom of the swirl combustion furnace 1 is iron and collected by, for example, a magnet. The recovered coarse and fine components are shown in Tables 2-4.

In the combustion of this steelmaking dust, it is a matter of course that the thermite reaction is caused by introducing aluminum into the furnace as a combustion aid, and the fuel in the auxiliary burner can be saved.

In the third embodiment, energy and remaining metals are recovered by incinerating a so-called shredder dust obtained by crushing a scrap car with a shredder and removing metals. Ordinary shredder dust contains plastics including vinyl chloride, wire harnesses including copper wire, and others, and when incinerated, dioxins are generated.

Since the above shredder dust is intertwined with various plastics, synthetic rubbers, metals, fibers, earth and sand, etc., and specific gravity difference selection by dry method is impossible, in the present invention, the dust is wet. One side was pulverized to 5 mm or less by a crusher (for example, “Disintegrator” manufactured by Komatsu Zenoah), introduced into water, and subjected to cyclone floating sorting. The shredder dust crushed by using such a wet crusher becomes a uniform solid-liquid mixture in which solid matter is dispersed in the liquid, so that stable transportation to the next process is possible, and further entangled dust is Almost separated, it was possible to easily separate the specific gravity difference thereafter. In this way, plastics (non-vinyl chloride type) with low chlorine content floating in water and combustibles typified by fibers could be easily selected and collected due to the difference in specific gravity from those having a higher specific gravity.

As a result, the sedimented metals such as copper and vinyl chloride are further separated, and the metals such as copper are recycled as resources, and the vinyl chloride and the like are buried underground. Resin such as polyethylene and polypropylene that floated by this floating sorting (Table 5) contains some vinyl chloride and copper in the harness. In Example 3, the floated material (low chlorine-containing combustible material in Table 5) is dried and melted and solidified by an extrusion molding machine or the like to form a solid fuel, and the system 1 collects thermal energy, copper, and the like. It is what.

That is, 30 kg / hr of the solidified fuel was charged into the swirl combustion furnace 2 and burned. The combustion fly ash swirling in the combustion furnace 2 having a high specific gravity and a high melting point falls to the bottom in the inner cylinder. Combustion fly ash that has fallen into the inner cylinder is taken out from the take-out port 2e. For example, iron powder is selectively collected with a magnet. Also, metals such as low copper melting point is led through a flue gas tube 2c to the high-temperature heat exchanger 3 with fly ash, are dust collection and further separated from the gas at a high temperature dust collector 4. Since the temperature of the gas has already dropped, it is further cleaned by applying the dust collector 6 and released into the atmosphere. The soot trapped by the heat exchange pipe 3c of the high temperature heat exchanger 3 and the ceramic filter 4c of the high temperature dust collector 4 was taken out from the discharge port 4e and the like, and metals such as copper were collected.

In this system 1, since the swirl flow in the swirl combustion furnace 2 is high-temperature air blown from the high-temperature heat exchanger 3, the temperature in the furnace 2 is kept high, even if vinyl chloride is incinerated. Hardly produces dioxins. Further, in the high-temperature heat exchanger 3, the combustion exhaust gas is kept at 400 to 600 ° C., so that the generation of dioxins is similarly suppressed. In this example, the dioxin in the fly ash was 0.005 mg / g, the dioxin in the exhaust gas was 0.30 ng / m ³ N, and the recovered heat amount was 85,000 kcal / hr.

  It has long been said that there is a limit to the landfill of waste, and today, the number of discarded vehicles is increasing every year. The energy and valuable metal recovery system according to the present invention performs incineration at high temperature and recovery of metals, and since the generation of dioxins is suppressed, further progress of the automobile industry is backed up.

1 is a schematic diagram of a combustion system according to the present invention. It is the partial cross section figure which showed the principal part of the high temperature heat exchanger. It is the center sectional view showing the outline of the high temperature dust collector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Energy and valuable metal recovery system 2 Swirling combustion furnace 3 High temperature heat exchanger 3c High temperature heat exchange pipe 4 High temperature dust collector 4c Ceramic filter for high temperature dust collector 5 Heat exchanger 6 Dust collector 7 Attracting exhaust fan 8, 9 Blower

Claims (1)

Turning combustion furnace (2), a high temperature heat exchanger (3), Se la Mick fiber filter hot dust collector using the (4), heat exchanger (5), a dust collector to the heat exchanger (5) (6 ) With or without induction fan (7) in order ,
The hot heat exchanger (3) to the high temperature heat exchanger (3) the swivel combustion furnace and heated to a high temperature through a ceramic pipe (2) blower blown therein from the lower end side wall of the outside air (9) Attached,
In the swirl combustion furnace (2), an inner cylinder (2b) having a foreign matter outlet (2e) formed at the bottom thereof is inserted and erected in the center of the bottom of the swirl combustion furnace (2), and the inner cylinder (2b) the upper end of it from being inserted into the small diameter or large diameter discharge Ento (2c) Gao-overlap-shaped, in the configuration of connecting the other end to the high temperature heat exchanger (3),
Wherein the high-temperature heat exchanger (3) is fired heat resistance temperature 600 ° C. or more heat exchange pipe made of silicon carbide are mounted at 1800 ° C. or higher,
The hot dust collector (4) ceramic fiber filter attached to the recovery of thermal energy and valuable metal, which is a fired heat resistance temperature 600 ° C. or more ceramic alumina silica at 1000 ° C. or higher temperature Waste disposal equipment.

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