JP2000337616A - Melting method and furnace for combustible waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate combustion of combustible wastes and miniaturize a melting furnace in melting method and furnace for supplying wastes including combustible ones to the melting furnace as processing objects, introducing the same into a main chamber for melting treatment, and heating the same in a slightly oxidizing atmosphere therein until they are melt at the surface F thereof and formed into melt slag. SOLUTION: A processing object supply section 10 for supplying processing objects 15 to a main chamber 9 is provided with a water supply system 14 for supplying moisture to the processing objects 15 to let combustible wastes 17 hold the moisture in advance so as to induce water-gas shift reaction in the main chamber 9 between carbon in the combustible wastes 17 and the moisture held therein. Combustible gas generated by the water-gas reaction is burnt on the surface F of the processing objects 15 and in the neighborhood thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a furnace for melting combustible waste, and more particularly to a first step of supplying waste containing combustible waste to a melting furnace as an object to be treated. And a second step of guiding the supplied workpiece to a main chamber for melting and heating the workpiece in a weakly oxidizing atmosphere to melt the surface of the workpiece to form a molten slag. A method of melting the combustible waste comprising a third step, and a deposition section for accumulating the article to be treated including the combustible waste, and treating the article supplied from the deposition section in a weakly oxidizing atmosphere. The present invention relates to a flammable waste melting processing furnace provided with a main chamber for heating and melting, and a slag discharge section provided at the bottom of the main chamber for discharging molten slag generated by melting the surface of the object.

[0002]

2. Description of the Related Art Conventionally, in a combustible waste melting apparatus, as shown in FIG. 6, for example, a melting furnace 1 has a fixed inner cylinder 2 and a rotary drive around a coaxial center with the inner cylinder 2. The outer cylinder 7 is freely provided and has a bottom 8, and a stacking section S is provided between the furnace ceiling 3 provided in the inner cylinder 2 and the bottom 8.
A main chamber 9 for heating and melting the object 15 supplied from the furnace under a weakly oxidizing atmosphere is formed on the bottom 8 of the main chamber 9 to form a mortar-shaped surface F of the object 15. Discharging section 8a for discharging molten slag 24 generated by melting
And was provided. The furnace ceiling 3 is provided with an air nozzle 5 for supplying primary air into the main chamber 9 and a burner 4 for supplying fuel to the main chamber 9 and burning the supplied fuel. The fuel supply passage 18 is connected to the burner 4, and the air supply passage 19 is connected to the burner 4 and the air nozzle 5, respectively. The space is heated, and the heat is used to melt the object 15 on the surface F. To this end, a fuel control valve 21 provided in the fuel supply path 18, a burner air control valve 22 provided in the air supply path 19 to the burner 4, and a main chamber air provided in the air supply path 19 to the air nozzle 5 The control valves 23 are configured to be controlled by the in-furnace temperature control means 20, respectively. The combustible waste 17 in the object 15 is also burned by the heat in the furnace and the primary air. To maintain the temperature in the furnace by the heat, the combustion of the combustible waste 17 is required. The speed is low and does not generate enough heat. The stacking unit S is configured to accumulate on the bottom 8 the object 15 including the combustible waste 17 supplied through an annular space between the inner cylinder 2 and the outer cylinder 7. An input section 11 for inputting the processing object 15 into the annular space in the annular ceiling section 6 which seals the annular space; and a deposition section for supplying the processing object 15 to the surface F with respect to the main chamber 9. S and
The processing object supply unit 10 was formed by the charging unit 11. From the stacking section S, a processing object 15 in the stacking section S is scraped out toward the main chamber 9 by a cutting blade 13 provided at a lower end 2 a of the inner cylinder 2.

[0003] As described above, the combustible waste 17 is also supplied from the article supply unit 10, but usually, the heat of the combustible waste 17 which has been subjected to a thermal decomposition process is usually used. The char which is the decomposition residue is thrown in.

[0004]

In the above-mentioned conventional waste melting furnace, the combustible waste 17 is used.
The char obtained by the prior pyrolysis treatment at the time of melting treatment is charged into the furnace as the object to be treated 15, and the char performs solid combustion in the furnace, so that the burning rate is low and the furnace temperature is low. Cannot be maintained at a temperature sufficient to melt the incombustibles in the processing object 15, and
If the residence time of the combustible waste 17 in the furnace is not enough,
There is a problem that the char may be discharged from the slag discharge section 8a as unburned matter. further,
From the viewpoint of preventing dioxin emission, there is also a problem that the size of the melting furnace increases if an attempt is made to ensure a sufficient residence time of the workpiece 15 in the furnace so as not to discharge unburned components. As a countermeasure, it has been previously proposed that steam be injected into the main chamber 9 in order to induce a water gasification reaction on the surface F of the object 15 in the main chamber 9 (Japanese Patent Application No. 8-232166). issue). That is,
As shown in FIG. 7, a steam supply mechanism 25 is provided in the melting furnace 1, and a steam nozzle 26 is arranged on the furnace ceiling 3. Although the combustion rate of the flammable waste 17 was improved by this, steam was blown into the high-temperature gas in the main chamber 9. Therefore, the burning rate of the combustible waste 17 did not increase to a satisfactory level.

Accordingly, an object of the present invention is to solve the above-mentioned problems, to provide means for promoting the combustion of combustible waste, and making the melting furnace compact.

[0006]

Means for Solving the Problems The first characteristic means of the waste melting method of the present invention for the above purpose includes a combustible waste as defined in claim 1. A first step of supplying waste to the melting furnace as a treatment object, a second step of leading the supplied treatment object to a main chamber for melting treatment, and heating the treatment object in a weakly oxidizing atmosphere. And a third step of melting the surface of the object to form a molten slag, the method comprising:
Prior to the second step, at least the flammable waste, a humidifying step of retaining moisture in advance, and in the third step, the carbon in the combustible waste and the retained moisture in the main chamber in the main chamber A water gasification step of inducing a water gasification reaction between the two, wherein the combustible gas generated by the water gasification reaction is burned on the surface of the object to be treated and in the vicinity thereof. That is, prior to the first step, or together with the first step, or prior to the second step after the first step, performing the humidification step, prior to the third step, moisture, at least It is kept in the combustible waste. According to a second aspect of the present invention, there is provided a method of melting waste according to the first aspect, wherein the humidification step comprises:
After the first step, water is sprayed and supplied to the whole of the object to be treated, so that the object to be treated retains moisture. That is, it is possible to retain the moisture in the combustible waste by retaining the moisture in the object to be treated.

[Function and Effect of Each Characteristic Means] According to the first characteristic means, the burning rate of combustible waste can be increased, and the melting furnace can be reduced in size. In other words, if a water gasification reaction is induced between the carbon content in the waste and the retained water in a weakly oxidizing atmosphere maintained at a high temperature, the burning rate of the flammable gas generated is high, Since the gas starts burning immediately, the carbon content surrounded by the combustion flame of the combustible gas rapidly burns. Therefore, the burning rate of the combustible waste can be increased, and the residence time of the combustible waste in the furnace can be shortened. As a result, the combustible waste has a low burning rate, even if it is only char that is a carbonized residue, it is possible to burn rapidly.
It is not necessary to increase the residence time of the object in the furnace,
It is not necessary to increase the reaction surface area of the deposition section. According to the second feature configuration, the operation of the humidification process is simplified while the operation and effect of the first feature configuration are exhibited. That is, there is no need to sort and humidify combustible waste. Also, because it is humidified in the melting furnace,
The entire object to be treated is heated by the ambient temperature, and the moisture contained in the non-combustible object evaporates, so that the combustible waste is surrounded as vapor together with the moisture contained in the combustible waste. Further, since the object is humidified in a closed space in the furnace, the object to be treated can be maintained in a humidified state. As a result, the water easily comes into contact with the carbon content in the combustible waste, and a water gasification reaction is induced.

According to a first aspect of the present invention, there is provided a waste melting treatment furnace for accumulating an object to be treated including combustible waste. A deposition section, a main chamber that heats and melts the object to be supplied supplied from the deposition section under a weakly oxidizing atmosphere, and a molten slag generated by melting the surface of the object to be processed at the bottom of the main chamber. A slag discharge unit for discharging the flammable waste in a melting processing furnace provided with a slag discharge unit, and a water supply mechanism for supplying moisture to the processing object to a processing object supply unit for supplying the processing object to the main chamber. Is provided. That is, by supplying water to the object to be treated from the water supply mechanism, water can be supplied to the combustible waste in the object to be treated. In addition, the water supply mechanism may be configured to divide the object to be treated and supply the moisture only to the combustible waste. As a second characteristic configuration of the waste melting furnace, the processing object supply unit in the first characteristic configuration may be a charging unit for charging a processing object into a deposition unit and the deposition unit. And a water supply mechanism is preferably provided in the charging section. As a third characteristic configuration of the melting processing furnace, as described in claim 5, the melting furnace in the first characteristic configuration can be rotatably driven around a fixed inner cylinder and a coaxial center with the inner cylinder, A main chamber is formed between a furnace ceiling provided in the inner cylinder and the bottom provided in the outer cylinder, and an annular space is provided between the inner cylinder and the outer cylinder. In addition to providing the charging section on the ceiling portion, and providing a water spray mechanism for supplying water to the object to be processed by spraying water toward the deposition section on the ceiling portion, if the water supply mechanism is configured Even better.

[Functions and Effects of Each Characteristic Configuration] According to the first characteristic configuration, the functions and effects provided by the first characteristic means can be realized. That is, since the water supply mechanism is provided in the processing object supply unit, the carbon in the combustible waste in the main chamber and the water supplied from the water supply mechanism and held in at least the combustible waste A water gasification step for inducing a water gasification reaction during the reaction can be performed in the main chamber. Naturally, the water content of the object to be treated other than the combustible waste is also evaporated in the furnace to form steam, and this steam can participate in the water gasification reaction. Therefore, if a water gasification reaction is induced between the carbon content of the waste and the water content of the object to be treated in a weakly oxidizing atmosphere maintained at a high temperature in the main chamber, the flammable gas generated Since the combustion speed of the combustible gas is high and the combustible gas starts burning immediately, the carbon content surrounded by the combustion flame of the combustible gas burns rapidly. As a result, the burning rate of combustible waste can be increased, the residence time of the combustible waste in the furnace can be shortened, and it is not necessary to increase the reaction surface area in the main chamber in the deposition section of the object to be treated. Thus, the size of the melting furnace can be reduced. According to the second characteristic configuration, the humidifying step can be performed prior to the first step, while the operation and effect provided by the first characteristic means are exhibited. In other words, by providing a water supply mechanism in the charging section,
Moisture can be supplied to the object to be processed prior to the input of the object to the deposition unit, and the humidified object to be processed is charged into the furnace, and the humidified object is stored in advance. The said deposition part can be formed. Therefore, the water content can be adjusted to a property suitable for the property of the object before being charged, and the water gasification step in the first characteristic means can smoothly proceed. Further, according to the third characteristic configuration, the second
The operation and effect of the characteristic means can be realized. In other words, since a water spray mechanism as a water supply mechanism is provided on the ceiling above the stacking section and relatively rotated with respect to the stacking section, water can be uniformly sprayed and supplied to the stacking section. It is possible to maintain the state in which the object to be processed is well humidified over the entire circumference. The water spray mechanism may be provided at one place of the ceiling, but if provided at a plurality of places,
A uniform humidified state can be achieved over the entire circumference of the deposition section. Therefore, the operation and effect of the second characteristic means can be exhibited.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a waste treatment method and a waste treatment apparatus according to the present invention. FIG. 1 is a longitudinal sectional view of an essential part showing an example of a melting furnace according to the present invention, and FIG. 2 is a process explanatory view showing an example of the furnace operation. The same elements as those described in the related art and elements having the same functions are denoted by the same reference numerals as those in FIGS. 6 and 7, and a part of the detailed description is omitted. .

In the waste melting furnace, as shown in FIG. 1, a melting furnace 1 is rotatably driven around a fixed inner cylinder 2 and a coaxial center with the inner cylinder 2, and the bottom portion 8 is The main chamber 9 is formed between the furnace ceiling 3 provided in the inner cylinder 2 and the bottom 8 provided in the outer cylinder 7. A stacking section S for accumulating a treatment object 15 including a combustible waste 17 on a bottom portion 8 of the main chamber 9 in an annular space between the inner cylinder 2 and the outer cylinder 7; And the outer cylinder 7
The object to be treated 15 is placed on the annular ceiling 6 of the annular space between
Is provided to the deposition unit S, and the workpiece supply unit 10 that supplies the workpiece 15 to the main chamber 9 is formed by the charging unit 11 and the deposition unit S. The bottom portion 8 is provided with a slag discharge portion 8a for discharging a molten slag 24 generated by melting the workpiece 15. In the main chamber 9, the workpiece 1 supplied from the deposition section S
The surface F formed in the mortar shape of No. 5 is heated and melted in a weakly oxidizing atmosphere. The molten slag 24 generated by melting the surface F is dropped from the slag discharge portion 8a toward a slag pit (not shown) provided below.

A water supply mechanism 1 is provided in the workpiece supply section 10.
4 is provided for keeping the combustible waste 17 in the object 15 to retain water, and the water supply mechanism 14 is used to supply and supply water to the accumulation section S. It is preferable that a mechanism 14A is provided on the annular ceiling 6. This is because, in the melting furnace 1 according to the present invention, since the inner cylinder 2 is fixed and the outer cylinder 7 is driven to rotate around the axis of the inner cylinder 2, the annular ceiling 6 is Since the water spray mechanism 14A is fixed to the annular ceiling 6 so as to relatively rotate on the stacking section S, the receiving side of the stacking section S is formed in an annular shape on the input section 11 side. Water is evenly supplied to the surface 16. In addition, since the deposition portion S is held in the closed space, it is possible to maintain the moisturizing condition by the supplied moisture. The amount of water supplied from the water supply mechanism 14 is determined by measuring the input amount of the processing object 15 by a measuring mechanism 12a attached to the processing object supply device 12 provided in the input section 11, and calculating the input amount. It is preferable to provide a water supply amount adjusting means 14a for setting a suitable water supply amount.
When supplying the char, that is, fixed carbon as the combustible waste 17, the water supply amount is:
It is desirable to set it to 5 to 10%. If less water is supplied, the char may not completely participate in the water gasification reaction and may leave unburned carbon, and if the amount of water is too large, the excess water In some cases, the latent heat of vaporization is deprived and the temperature inside the furnace is lowered, and the water gasification reaction may not stably occur. By the way, 5 to 1
The char containing 0% of water is hard to agglomerate, and becomes a state of easy to handle as a collection of small clumps.

In the waste melting furnace configured as described above, for example, as shown in FIG. 2, flammable waste is supplied by a workpiece supply device 12 provided at an input section 11 of a workpiece supply section 10. A first step of supplying the waste containing the object 17 as the object to be processed 15 to the deposition section S of the melting furnace 1, and guiding the supplied object to be processed 15 from the deposition section S to the main chamber 9 for performing the melting process. A second step, and a third step of heating the workpiece 15 in a weakly oxidizing atmosphere in the main chamber 9 to melt the surface F of the workpiece 15 to form a molten slag; It is performed sequentially and continuously.

Here, a water spray mechanism 14A is provided as a water supply mechanism 14 on the annular ceiling section 6 above the accumulation section S, so that after the first step, the entire processing object 15 is By spraying and supplying water prior to the second step and causing the object 15 to retain the moisture, the humidifying step of retaining the moisture in at least the combustible waste 17 is performed. Further, the main chamber 9 of the deposition section S
The combustible waste 17 is supplied to the inner surface F in this manner while retaining moisture, so that in the third step, the carbon in the combustible waste 17 and the retained carbon are contained in the main chamber 9. A water gasification step for inducing a water gasification reaction with the let-off moisture is performed, and combustible gas generated by the water gasification reaction is burned on the surface F of the article 15 to be processed and its vicinity. Can be. In the case where the combustible waste 17 contains a volatile component, the amount of water held in the treatment target 15 in the humidification step is based on the carbon content of the combustible waste 17 after carbonization in the combustible waste 17. 5-10%
The amount may be any amount corresponding to the water content.

With the above configuration, the combustible waste 17
Since the flammable gas burns around the solid carbon generated by thermal decomposition, the combustion of the solid carbon is promoted, and the melting processing speed becomes extremely high. Therefore, the area of the surface F, which is the reaction surface of the workpiece 13 in the deposition section S, can be reduced, and as a result, the melting furnace 1 is formed in a small size in combination with the high melting processing speed. You can.

Next, another embodiment of the present invention will be described. <1> In the above embodiment, the melting furnace 1 is composed of the fixed inner cylinder 2 and the outer cylinder 7 that is rotatable around the same axis as the inner cylinder 2 and that has the bottom 8. And the inner cylinder 2
Although the example in which the main chamber 9 is formed between the furnace ceiling 3 provided in the above and the bottom 8 provided in the outer cylinder 7 has been described, the outer cylinder 7 is also fixed to the inner cylinder 2. There may be. However, in this case, it is preferable that the water supply mechanism 14 be configured to supply water evenly to the deposition unit S, or to be provided before the charging unit 11 of the workpiece supply unit 10. <2> In the above embodiment, the example in which the workpiece supply device 12 is provided in the charging section 11 has been illustrated and described. However, instead of the workpiece supply device 12, a receiving hopper including only a seal damper is provided. May be provided. <3> In the above embodiment, an example was described in which the water supply mechanism 14 was configured by providing the water spray mechanism 14A for spraying and supplying water to the deposition section S on the annular ceiling section 6; The mechanism 14 may be configured to supply water dropwise to the deposition unit S. Also, for example, as shown in FIG.
The water supply mechanism 14 is connected to the input section 11 of the workpiece supply section 10.
Is provided in the processing object supply device 12 provided in the apparatus, and supplies moisture to the whole of the processing object 15 to be thrown in.
In addition, moisture may be retained in the nonflammable workpiece. Further, moisture may be added to the workpiece 15 before reaching the workpiece supply device 12. In this way, the moisture contained in the non-combustible object 15 evaporates due to the heat in the furnace and becomes steam, which surrounds the combustible waste 17 and promotes the water gasification reaction. May be possible. Further, when the combustible waste 17 is batch-injected, the water supply mechanism 1 is provided upstream of the workpiece supply unit 10 prior to the first step.
It is also possible to dispose the fuel tank 4 and to supply the combustible waste 17 to the charging section 11 while keeping the combustible waste 17 wet. With this configuration, the combustible waste 17 is divided and
It is possible to add water only to the flammable waste 17, and it is easy to adjust the water to be retained in the flammable waste 17. <4> That is, in the above embodiment, an example in which the humidification step is performed between the first step and the second step has been described. However, the humidification step may be performed before the second step. For example, using the melting furnace shown in FIG.
As shown in FIG. 5, the humidification step may be performed in the first step, or, for example, as shown in FIG. 5, the humidification step may be performed prior to the first step. .

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an essential part showing an example of a melting furnace according to the present invention.

FIG. 2 is a flowchart illustrating an example of a waste melting method according to the present invention.

FIG. 3 is a longitudinal sectional view showing a main part of another example of the melting furnace according to the present invention.

FIG. 4 is a flowchart illustrating another example of the waste melting method according to the present invention.

FIG. 5 is a flowchart illustrating another example of the waste melting method according to the present invention.

FIG. 6 is a partially cutaway perspective view of an essential part showing an example of a conventional melting processing furnace.

FIG. 7 is a partially cutaway perspective view of a main part showing another example of a conventional melting processing furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melting furnace 2 Inner cylinder 3 Furnace ceiling part 4 Annular ceiling part 5 Outer cylinder 6 Bottom part 6a Slag discharge part 7 Main chamber 8 Treatment supply part 9 Input part 12 Water supply mechanism 13 Treatment part 15 Combustible waste F Cover Surface of treated material S Deposit

Claims (5)

[Claims] 1. A first step of supplying waste containing combustible waste (17) to a melting furnace (1) as an object to be treated (15), and melting the supplied object to be treated (15). A second step of leading to the main chamber (9) to be treated, and heating the object (15) in a weakly oxidizing atmosphere to melt the surface (F) of the object (15) to remove molten slag. A humidifying method for melting a combustible waste, comprising: a humidifying step of preliminarily holding moisture in at least the combustible waste (17) prior to the second step. A water gasification step of inducing a water gasification reaction between the carbon in the combustible waste (17) and the retained moisture in the main chamber (9). The combustible gas generated by the conversion reaction is transferred to the surface (F) of the object (15) and the Melt processing method of the combustible waste is burned in the vicinity. 2. After the first step, as the humidification step, water is spray-supplied to the entire object to be treated (15) so that the object (15) retains the moisture. A method for melting combustible waste according to claim 1. 3. A deposition section (S) for accumulating an object to be treated (15) containing combustible waste (17), and said deposition section (S).
A main chamber (9) for heating and melting an object to be treated (15) supplied from a weak oxidizing atmosphere and a bottom (8) of the main chamber (9) are provided on the surface ( A slag discharge section (8a) for discharging molten slag generated by melting F)
And a melting processing furnace for combustible waste provided with: a processing object supply section (10) for supplying the processing object (15) to the main chamber (9); A) a combustible waste melting processing furnace provided with a water supply mechanism (14) for supplying water to the combustible waste. 4. The processing object supply section (10) includes an input section (11) for inputting the processing object (15) into the deposition section (S) and the deposition section (S), The furnace for melting combustible waste according to claim 3, wherein the water supply mechanism (14) is provided in the charging section (11). 5. An outer cylinder (7) having a fixed inner cylinder (2) and a rotatable drive around a coaxial center with the inner cylinder (2) and having the bottom (8). ), And a furnace ceiling part (3) provided in the inner cylinder (2) and the outer cylinder (7).
The main chamber (9) is formed between the inner chamber (2) and the outer cylinder (7), and the main chamber (9) is formed between the inner cylinder (2) and the outer cylinder (7). A water spray mechanism (14) for providing an injection section (11) and spraying and supplying water to the deposition section (S);
The furnace for melting combustible waste according to claim 3, wherein A) is provided on the annular ceiling (6) to constitute the water supply mechanism (14).