APPARATUS FOR TREATING WASTE WITH HIGH TEMPERATURE AND METHOD THEREOF

Technical Field

[1] The present invention generally relates to apparatus and methods for treating waste with high temperature, and more specifically, to apparatus and methods for treating waste with high temperature, which make it possible to construct a small-sized treatment facility so that it is advantageous in commercialization, to significantly lower the power consumption of the facility, and further, to treat difficult waste more effectively, thereby making it harmless. Background Art

[2] Incessant progress of industrialization and urbanization has provided wealth and convenience in our modern lives. However, the artificial environment from such development and urbanization has overwhelmed the natural environment, which in turn, has caused to produce more and more varieties of waste. Accordingly, environmental problems related to various wastes have begun to occur.

[3] Among the variety of wastes, there has been more and more materials that are hardly decomposed naturally, which has become way over the limit of natural purification and absorption. In addition, the amount of such wastes has increased rapidly, thereby making a national and global issue. Therefore, there is a great need to find solutions for such wastes.

[4] Here, waste treatment means a kind of process that reduces or recycles wastes or makes such wastes harmless through physical, chemical or biological operation with a certain system.

[5] In agricultural and nomadic societies, wastes produced by economic activities were decomposed or absorbed naturally by the self-purification of the nature, thereby making no problem at all. However, rapid development due to industrialization has caused more varieties and amount of wastes to be produced, and accordingly, a lot of problems related to the treatment of such wastes have begun to occur, making it a national and global issue.

[6] There exist various techniques to treat and make wastes such as PCB

(poly chlorinated biphenyl) or dioxins harmless, among other wastes. (Hereinafter, such wastes are referred to as difficult wastes.) Of such techniques, in particular, a method of pyrolytic waste treatment at high temperature (heat treatment) is known to be effective.

[7] In addition, techniques for treating difficult wastes are known from a cited reference 1 (Japanese Patent Publication 2001-220609), a cited reference 2 (Japanese Patent Publication 2001-248813) and so on.

[8] The technique known from the cited reference 1 is so called a vertical melting- reduction method in which difficult wastes are subject to melting treatment into gaseous state through a series of multiple vertical smelting-reduction furnaces.

[9] The technique known from the cited reference 2 is a heat treatment in which wastes are fed into an electric furnace to go through pyrolysis.

[10] In order to implement the technique of the cited reference 1, it is required to use a number of furnace bodies such as vertical shaft furnace, a blast furnace, a reduction furnace or the like, which has a drawback in that the facility needs large installation area because a large-scaled plant is necessary.

[11] For the cited reference 2, the technique has a disadvantage in that it causes an increase in power consumption due to the power required for the operation of the electric furnace since wastes are subject to pyrolysis using the electric furnace. Disclosure of Invention Technical Problem

[12] Therefore, it is an object of the present invention to provide apparatus and methods for treating waste with high temperature, which make it possible to construct a small- sized treatment facility so that it is advantageous in commercialization, to significantly lower power consumption of the treatment facility, and further, to treat difficult wastes more effectively, thereby making it harmless.

Technical Solution

[13] The above object is achieved by an apparatus for treating waste with high temperature comprising: a furnace wall defining a furnace chamber therein, the furnace chamber being a space where difficult wastes are treated; a furnace chamber heating unit for increasing the temperature inside the furnace chamber; a storage tank provided on the outside of the furnace wall for storing the difficult wastes to be fed into the furnace chamber; a difficult waste pre-heating unit for feeding the difficult wastes from the storage tank into the furnace chamber while pre-heating and evaporating the difficult wastes; an air feeder for feeding air into the furnace chamber; and an exhaust unit for discharging the air produced inside the furnace chamber to the outside.

[14] Here, the furnace wall may be manufactured from a heat-resistant furnace material containing quartz.

[15] The ceiling part of the furnace wall may have the shape of a dome, and a slope chute with a downward inclination toward the exhaust unit from one side of the upper part of the furnace wall is provided on one side of the lower part of the furnace chamber.

[16] Across the slope chute, an auxiliary slope wall with a downward inclination toward the slope chute is projected from a higher location of the furnace wall than the highest part of the slope chute. A vent is provided between the slope cute and the bottom of the auxiliary slope wall to vertically pass through the slope chute and the auxiliary slope wall.

[17] The furnace chamber heating unit may comprise: at least one heating burner provided on one side of the furnace wall for increasing the temperature inside the furnace chamber with the heat of combustion of flames spouting toward the interior of the furnace chamber; and an inorganic particle feeding unit for feeding inorganic particles into the furnace chamber to heat the interior of the furnace chamber with the heat of reaction of the inorganic particles.

[18] The at least one burner may comprise two heating burners, and the two heating burners are provided on the opposite sides of the vertical parts of the furnace wall at different heights so that the two heating burners can spout flames into the furnace chamber through flame nozzles thereof at their corresponding locations.

[19] The fuel used in the heating burner may comprise a mixture of water and waste oil in emulsion, in the ratio of water to waste oil 45: 55.

[20] The inorganic particle feeding unit may comprise a particle storage tank for storing the inorganic particles, and a particle feeding passage connected with the particle storage tank and the furnace chamber for feeding the inorganic particles from the particle storage tank to the furnace chamber.

[21] The inorganic particles may comprise a mixture of iron oxide particles and aluminum particles.

[22] The difficult waste pre-heating unit may comprise a first heated feeding passage provided inside the auxiliary slope wall, a second heated feeding passage provided inside the slope chute for being in communication with the first heated feeding passage at one side and for being connected to a cooler at the rear end thereof, a feed passage for connecting the cooler and a feeding inlet provided through the ceiling area of the furnace chamber, and an exterior pipe connected to the first heated feeding passage and the storage tank, respectively, at both ends.

[23] The first heated feeding passage may be arranged in zigzag inside the auxiliary slope wall, and the exterior pipe may be formed with one way from the storage tank, be divided into two branches at a certain point, and then be connected to the first heated feeding passage by both branches, respectively.

[24] The air feeder may comprise an air feed opening formed on the furnace wall for supplying the air produced by a blower into the furnace chamber, and at least one air feed passage for guiding the air flowing in through the air feed opening to the furnace chamber.

[25] The apparatus of the present invention may further comprise a cooling unit provided at the rear part of the exhaust unit along the direction of air exhaust for cooling down the air discharged from the exhaust unit. [26] The apparatus of the present invention may further comprise a filter device for filtering the air that has been cooled down at the cooling unit. [27] The apparatus of the present invention may further comprise a feedback passage for connecting the exhaust unit and the air feeder to feed a part of the air discharged from the exhaust unit back to the furnace chamber through the air feeder. [28] The apparatus of the present invention may further comprise a sludge collection unit provided at the bottom of the furnace chamber for collecting melted sludge produced inside the furnace chamber. [29] The sludge collection unit may further comprise a closable opening formed at the bottom of the furnace chamber that is tapered downward in the form of a funnel, and a collector vessel provided underneath the closable opening. [30] The above object is further achieved by a method for treating waste comprising the steps of: heating the furnace chamber that has been fed with difficult waste for treating the difficult waste; pre-heating and evaporating the difficult waste; pyrolizing the difficult waste in the furnace chamber by feeding the difficult waste that has been preheated and evaporated into the furnace chamber; discharging the air produced inside the furnace chamber to the outside. [31] Here, the step of heating the furnace chamber may comprise the heat of combustion by at least one heating burner that spouts flames into the furnace chamber, and the heat of reaction of inorganic particles fed into the furnace chamber. [32] The method of the present invention may further comprise the step of cooling down the discharged air after the step of discharging. [33] The method of the present invention may further comprise the step of filtering the air that has been cooled down after the step of cooling. [34] The method of the present invention may further comprise the step of feeding a part of the air being discharged at the step of discharging back to the furnace chamber. [35] The method of the present invention may further comprise the step of collecting melted sludge produced inside the furnace chamber.

Advantageous Effects

[36] According to the present invention, it is possible to construct a small-sized treatment facility so that it is advantageous in commercialization, to significantly lower the power consumption of the facility, and further, to treat difficult waste more effectively, thereby making it harmless. Brief Description of Drawings

[37] These and other features, aspects, and advantages of the present invention will be apparent from the following description, appended claims, and accompanying drawings, in which like components are referred to by like reference numerals. In the drawings:

[38] Fig. 1 is a vertical sectional view of an apparatus for treating waste with high temperature according to an embodiment of the present invention;

[39] Fig. 2 is a sectional view along A-A of Fig. 1 ;

[40] Fig. 3 is a sectional view along B-B of Fig. 1; and

[41] Fig. 4 is a sectional view along C-C of Fig. 1.

Best Mode for Carrying out the Invention

[42] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[43] Fig. 1 is a vertical sectional view of an apparatus for treating waste with high temperature according to an embodiment of the present invention, Fig. 2 is a sectional view along A-A, Fig. 3 is a sectional view along B-B, and Fig. 4 is a sectional view along C-C of Fig. 1, respectively.

[44] Before a detailed description of the present invention with reference to the drawings, it is elaborated that the invention is an apparatus for treating waste, in other words, an apparatus for treating difficult wastes such as PCB (polychlorinated biphenyl) or dioxin that is hard to treat in a simple usual way of treatment. That is, such difficult wastes can be made harmless by treating the wastes with the apparatus for treating waste with high temperature of the present invention.

[45] However, since the present invention is not limited to such wastes only, any kind of difficult wastes other than PCB or dioxin or simple common waste can be treated and made harmless using the apparatus of the invention. Especially, the present invention has advantages in that it can be constructed in a small-sized treatment facility compared with the prior art, thereby making it advantageous in commercialization, and in that it is possible to significantly lower the power consumption of the facility.

[46] Now, an apparatus for treating waste with high temperature of a preferred embodiment of the present invention will be described with reference to the Figs. 1 to 4.

[47] As shown in the Figs. 1 to 4, the apparatus for treating waste with high temperature of the embodiment comprises: a furnace wall (8) defining a furnace chamber (4) which is the space where wastes are treated through a treatment such as pyrolysis; a furnace chamber heating unit (not shown) for increasing the temperature inside the furnace chamber (4); a storage tank (1) provided outside the furnace wall (8) for storing the difficult wastes to be fed into the furnace chamber (4); a difficult waste pre-heating unit (not shown) for feeding the difficult wastes into the furnace chamber (4) while pre-heating and evaporating the difficult wastes; an air feeder (2) for feeding air into the furnace chamber (4); and an exhaust unit (11) for discharging the air produced inside the furnace chamber (4) to the outside. Next, the construction of each component will be described.

[48] The furnace wall (8) forms the external part of the apparatus for treating waste with high temperature of the present invention. In other words, it is safe to say that the furnace wall (8) acts as the body of the apparatus for treating waste with high temperature of the embodiment. As shown in the Fig. 1, since it is possible to construct the furnace wall (9) in a small-sized facility with a predetermined volume, it is easy to use compared with conventional treatment apparatus.

[49] In the embodiment, the furnace wall (8) is made of a heat-resistant furnace material.

Thus, the furnace wall (8) is prevented from damage or deformation even when the temperature inside the furnace chamber goes up very high.

[50] In particular, since the furnace wall (8) of the embodiment is made of a heat-resistant furnace material containing quartz, the inner surface of the furnace wall (8) turns into a state of enamel due to the SiO (silicon dioxide) which is the main ingredient of the quartz when the temperature reaches at about 1800 ⁰ C. Accordingly, as will be described later, the melted material of the difficult wastes fed into the furnace chamber (4) does not stick on the inner surface of the furnace wall (8) and runs down along the inner surface, so that the corrosion resistance and durability of the furnace wall (8) can be improved and furthermore, the pyrolysis inside the furnace chamber (4) can be expedited.

[51] The ceiling part of the furnace chamber (4) formed inside the furnace wall (8) has the shape of a dome. And, a slope chute (14) is provided on one side of the lower part of the furnace chamber (4). Due to such construction, the furnace chamber (4) is generally tapered downward in the form of so called a funnel.

[52] Across the slope chute (14), an auxiliary slope wall (12) with a downward inclination toward the slope chute (14) is projected from a higher location of the furnace wall (8) than the highest part of the slope chute (14).

[53] A first heated feeding passage (3) is provided inside the auxiliary slope wall (12), and the first heated feeding passage (3) is in communication with a second heated feeding passage (20) provided inside the slope chute (14). In addition, the second heated feeding passage (20) is connected to a cooler (6), and a feed passage (24) is provided between the cooler (6) and a feeding inlet (7) formed through the ceiling area of the furnace chamber (4).

[54] As shown in the Fig. 3, the first heated feeding passage (3) is arranged in zigzag inside the auxiliary slope wall (12), and is in communication with the second heated feeding passage (20) at the end of the zigzag. The first heated feeding passage (3) and the storage tank (1) is connected to each other via an exterior pipe (3a).

[55] The slope chute (14) formed with an opposing angle to the auxiliary slope wall (12) on the extended line of the lower part of the auxiliary slope wall (12) has a downward inclination toward the exhaust unit (11) from an upper part of one side of the furnace wall (8). A vent (17) is provided between the slope cute (14) and the bottom of the auxiliary slope wall (12) to vertically pass through the slope chute (14) and the auxiliary slope wall (12).

[56] A plurality of air feed passages (2b) are installed inside the slope chute (12) for feeding the air supplied from the air feed opening (2a) to the furnace chamber (4). Moreover, apertures (15) are provided on the surface of the slope chute (14) for spraying the air fed via the air feed passages (2b) into the furnace chamber (4). Furthermore, the air supplied from the air feed opening (2a) may be fed through air feed passages (not shown) of different path and be sprayed into the furnace chamber (4) through apertures (13) provided on the surface of the auxiliary slope wall (12) (see Figs. 2 and 3).

[57] The bottom of the furnace chamber (4) is provided with a sludge collection unit (10) as a means for collecting melted sludge produced inside of the furnace chamber (4).

[58] The sludge collection unit (10) comprises a closable opening (10a) formed at the bottom of the furnace chamber (4) that is tapered downward in the form of a funnel, and a collector vessel (10b) provided underneath the closable opening (10a). Accordingly, when the closable opening (10a) is opened, the melted sludge produced inside the furnace chamber (4) is collected into the collector vessel (1 Ib) through the closable opening (10a).

[59] Next, the furnace chamber heating unit comprises: heating burners (5a, 5b) provided on one side of the furnace wall (8) for increasing the temperature inside the furnace chamber (4) with the heat of combustion of the flames spouting toward the interior of the furnace chamber (4); and an inorganic particle feeding unit (9) for feeding inorganic particles into the furnace chamber (4) to heat the interior of the furnace chamber (4) with the heat of reaction of the inorganic particles.

[60] Though it is possible to provide one heating burner only, there are two heating burners (5a, 5b) provided in the embodiment on both sides of the furnace wall (8), one per each side for the consideration of efficiency. However, since the present invention is not limited to such configuration, the number of heating burners(5a, 5b) may be selected or changed appropriately.

[61] In the preferred embodiment, there are two heating burners (5a, 5b) provided. The two heating burners (5a, 5b) are installed on the opposite sides of the vertical parts of the furnace wall (8) at different heights so that the two heating burners (5a, 5b) can spout flames (F) into the furnace chamber (4) through flame nozzles (18a, 18b) thereof at their corresponding locations.

[62] Now, take a look at the directions of the flames. The heating burner (5a) spouts flame

(F) toward the upper surface of the auxiliary slope wall (12), and the heating burner (5b) spouts flame (F) toward the slope chute (14). However, since the present invention is not limited to such case, the directions of the flames (F) need not necessarily to be the same as the embodiment.

[63] In the embodiment, a mixture of water and waste oil in emulsion in the ratio of water to waste oil 45: 55 is used as the fuel of the heating burners (5a, 5b). With the flames produced by such a mixture, the interior of the furnace chamber (4) reaches up to about 1700°C~l 85O ⁰ C. By using such a mixture, it is possible to reduce the amount of oil used.

[64] In addition, since a mixture of water and oil in emulsion is used, it is possible not only to reduce the amount of nitrogen oxides and sulfur oxides produced, but also to inhibit the generation of dioxins.

[65] The inorganic particle feeding unit (9) comprises a particle storage tank (9a) for storing the inorganic particles to be fed into the furnace chamber (4), and a particle feeding passage (9b) connected with the particle storage tank (9a) and the furnace chamber (4) for feeding the inorganic particles from the particle storage tank (9a) into the furnace chamber (4) inside the furnace wall (8). In this case, it is preferable for the particle storage tank (9a) to be provided at the overhead area of the furnace wall (8) so that the inorganic particles in the particle storage tank (9a) can be supplied into the furnace chamber (4) through the particle feeding passage (9b) by their own weight, in other words, by the weight in the direction of gravity. However, the present invention is not limited to such construction; the particle storage tank (9a) may be provided on any side of the furnace wall (8) other than the overhead area of the furnace wall (8).

[66] In the embodiment, a mixture of iron oxide particles and aluminum particles is used as the inorganic particle. By using such a mixture of iron oxide particles and aluminum particles as the inorganic particle, it is possible to increase the temperature of the furnace chamber (4) up to 2500°C~2700°C by the heat of reaction of the mixture, thereby making it possible to expedite the pyrolysis of difficult wastes such as PCB.

[67] In the mixture of iron oxide particles and aluminum particles, beach sand can be added. As a result of an experiment with the addition of beach sand, the present applicant found that the pyrolysis process of PCB was expedited by the generation of complex ion.

[68] The difficult waste pre-heating unit feeds the difficult wastes into the furnace chamber (4) while pre-heating and evaporating the difficult waste from the storage tank (1).

[69] The difficult waste pre-heating unit comprises: a first heated feeding passage (3) arranged in zigzag inside the auxiliary slope wall (12), a second heated feeding passage

(20) provided inside the slope chute (14) for being in communication with the first heated feeding passage (3) at one side and for being connected to a cooler (6) at the rear end thereof, a feed passage (24) for connecting the cooler (6) and a feeding inlet (7) provided through the ceiling area of the furnace chamber (4), and an exterior pipe (3a) connected to the first heated feeding passage (3) and the storage tank (1), respectively, at both ends.

[70] The exterior pipe (3a) can be constructed with one way from the storage tank (1), be divided into two branches at a certain point, and then be connected to the first heated feeding passage (3) by both branches, respectively.

[71] With such construction, the difficult wastes within the storage tank (1) makes a circulation path of the storage tank (1), the exterior pipe (3a), the first heated feeding passage (3), the second heated feeding passage (20), the cooler (6), the feed passage (24) and the feeding inlet (7), so as to be fed into the furnace chamber (4).

[72] The air feeder (2) comprises an air feed opening (2a) formed on the furnace wall (8) for supplying the air produced by a blower (not shown) into the furnace chamber (4), and an air feed passage for guiding the air flowing in through the air feed opening (2a) into the furnace chamber (4). Though the air feed opening (2a) is illustrated schematically in the Fig. 1, the air feed opening (2a) may be constructed to open and close manually or automatically with a separate door.

[73] The apparatus for treating waste with high temperature of the embodiment further comprises a cooling unit (21) provided at the rear part of the exhaust unit (11) along the direction of air exhaust for cooling down the air discharged from the exhaust unit (11), and a filter device (22) for filtering the air that has been cooled down at the cooling unit (21).

[74] The cooling unit (21) cools down the hot air produced by the pyrolysis process inside the furnace chamber (4) to about the atmospheric temperature. The filter device (22) eliminates any impurities from the air that has been cooled down. For such a filter device (22), a variety of filters can be installed such as a pre-filter, a HEPA filter, a dust collector filter etc.

[75] As such, the air discharged from the exhaust unit (11) passes through the cooling unit

(21) and the filter device (22), and then is eventually released into the air. Accordingly, it is possible to control the temperature of the air released to be close to the atmospheric temperature and to maintain the air in a clean state, thereby making it possible to prevent air pollution and to promote environmental preservation.

[76] In addition to the cooling unit (21) and filter device (22), the apparatus for treating waste with high temperature of the embodiment is further provided with a feedback passage (23) for connecting the exhaust unit (11) and the air feeder (2). [77] The feedback passage (23) feeds a part of the air discharged from the exhaust unit

(11) back to the furnace chamber (4) through the air feeder (2). As such, by feeding a part of the air discharged from the exhaust unit (11) back to the furnace chamber (4) instead of the air from outside, it is possible to prevent a sudden decrease in the temperature inside the furnace chamber (4) so that the pyrolysis process can be expedited.

[78] Now, the operation of the apparatus for treating waste with high temperature of such construction will be described.

[79] First, the heating burners (5a, 5b) are activated to make flames (F) spout from the heating burners (5a, 5b) into the furnace chamber (4). At the same time, air is supplied from the air feed opening (2a) into the furnace chamber (4) through the apertures (13, 15).

[80] As the air is fed and the heating burners (5a, 5b) are activated, the interior of the furnace chamber (4) is heated up to about 1700°C~l 85O ⁰ C by the heat of combustion of the heating burners (5a, 5b).

[81] When the interior of the furnace chamber (4) is heated up as above, the inorganic particles from the particle storage tank (9a) are fed into the furnace chamber (4) through the particle feeding passage (9b). Then, with the heat of reaction of the inorganic particles supplied, the interior of the furnace chamber (4) is heated up to about 2500 ⁰ C.

[82] While maintaining this state, the difficult waste from the storage tank (1) is fed into the furnace chamber (4). That is, the difficult waste within the storage tank (1) makes a circulation path of the storage tank (1), the exterior pipe (3a), the first heated feeding passage (3), the second heated feeding passage (20), the cooler (6), the feed passage (24) and the feeding inlet (7), so as to be fed into the furnace chamber (4).

[83] In this case, since the auxiliary slope wall (12) and slope chute (14) are already heated up to a high temperature by the hot temperature of furnace chamber (4), the difficult waste from the storage tank (1) is heated and evaporated while being fed into the furnace chamber (4), that is, while passing through the first heated feeding passage (3) and the second heated feeding passage (20) inside the auxiliary slope wall (12) and the slope chute (14), respectively.

[84] After evaporation, the difficult waste is cooled down at about 800 ⁰ C through the cooler (6), and is fed into the furnace chamber (4) through the feed passage (24) and the feeding inlet (7). Then, the difficult waste is pyrolized rather easily inside the furnace chamber (4).

[85] Next, the heated and evaporated difficult waste fed into the furnace chamber (4) that is maintained at high temperature with the heat of combustion by the heating burners (5a, 5b) and the heat of reaction by the inorganic particles, is pyrolized by the high temperature, and then is discharged outside the furnace chamber (4) through the exhaust unit (11).

[86] In this case, a part of the air inside the furnace chamber (4) is discharged outside the furnace chamber (4) through the exhaust unit (11), and the rest of the air is fed again into the furnace chamber (4) through the air feed opening (2a) via the feedback passage (23). Accordingly, it is possible to prevent the decrease in the temperature inside the furnace chamber (4) due to cold air flowing in from outside, and even to expedite the pyrolysis of the difficult waste.

[87] The air discharged through the exhaust unit (11) is cooled rapidly down to about -

3O ⁰ C by the cooler (21), and then is released into the air in a clean state after passing through the filter device (22).

[88] Since the air discharged through the exhaust unit (11) is eventually released into the air after passing through the cooler (21) and the filter device (22), it is possible not only to make the air close to the atmospheric temperature, but also to maintain the air in a clean state, thereby making it possible to prevent air pollution and to promote environmental preservation.

[89] Therefore, even for difficult wastes such as PCB, dioxins and so on, it is possible to treat the difficult wastes to make harmless by the pyrolysis process inside the furnace chamber (4) as described above. Especially, since the pyrolysis process of the embodiment is carried out simply by the heat of combustion by the heating burners (5a, 5b) and the heat of reaction by the inorganic particles, it is possible to significantly lower the power consumption of the facility over prior art.

[90] As described above, various remnants such as melted sludge produced by the pyrolysis of the difficult wastes during the treatment of the difficult wastes inside the furnace chamber (4) first run down slidingly along the inner surface of the furnace wall (8) which has the shape of a funnel as described above, and then are discharged through the closable opening (10a) formed at the bottom of the furnace chamber (4) to be collected into the collector vessel (10b).

[91] Therefore, if the apparatus for treating waste with high temperature of the embodiment is used, it is possible to treat difficult wastes such as PCB (Especially, it has been reported that PCB is hard to treat into harmless products) into harmless products with relatively lower energy and power consumption.

[92] In particular, since the apparatus for treating waste with high temperature of the preferred embodiment has a relatively simple construction formed of a furnace chamber (4) defined by a furnace wall (8), heating burners (5a, 5b), a particle feeding passage (9b), an air feed passage (2b), heated feeding passages (3, 20) for difficult wastes, an exhaust unit (11) and so on as described above, the apparatus has an advantage in that it does not need large installation area compared with the prior art treatment facilities.

[93] Therefore, according to the embodiment, it is possible to construct a small-sized treatment facility so that it is advantageous in commercialization, to significantly lower power consumption of the treatment facility, and further, to treat difficult wastes more effectively, thereby making it harmless.

[94] In the above embodiment, it is described that when a part of the air inside the furnace chamber (4) is discharged outside the furnace chamber (4) through the exhaust unit (11), the rest of the air is fed again into the furnace chamber (4) through the air feed opening (2a) via the feedback passage (23); however, this is not always the case, and the construction of feedback passage (23) may be omitted if necessary.

[95] The present invention has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.