JP2006194486A - Melting furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a melting furnace with superior maintainability. <P>SOLUTION: In a gasification melting furnace for combustibles, the combustibles are gasified, and then ash contents are melted in the melting furnace. The gasification melting furnace for combustibles is characterized by that a molten slag outlet is opened for discharging molten slag, a tubular discharge passage is extended downward from the molten slag outlet, a protruding part protruding more inward than an inner circumferential rim of the tubular discharge passage is provided on an inner face of the tubular discharge passage to check a downward flow by contacting the molten slag, and the protruding part is detachably provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a melting furnace for melting ash, and more particularly to a melting furnace for discharging ash into molten slag.

In order to extend the life of the final disposal site, a melting furnace is used that melts incineration residues such as ash generated by incineration of waste and combustible materials into slag that can be effectively used.
As such a melting furnace, after combustible material is gasified, the combustible gas generated by the gasification is combusted to melt the ash content in the combustible material, incombustible material, incineration residue and flying. A melting furnace such as an ash melting furnace that melts ash such as ash using plasma, arc, electric heater, fossil fuel, or the like is used.
Among these, gasification melting furnaces are widely used from the viewpoint of effective use of energy.
Such a gasification melting furnace is usually provided with a furnace body portion in which the inside is composed of a refractory material such as silicon carbide or alumina and the ash is melted, and the ash (molten slag) melted in the furnace body portion. ) Is provided. In this gasification and melting furnace, wastes are gasified in the gasification furnace and are usually decomposed into combustible gas, combustible solids and ash, and ash is produced together with combustible gas and combustible solids. The ash is introduced into the furnace body and heated to a temperature higher than the melting temperature of ash (for example, 1300 ° C.) by combustion of combustible gas and combustible solids, and the ash is melted into slag. If such ash melting continues, the molten slag will eventually flow from the molten slag outlet through the tubular outlet and into a water tank or the like disposed below the molten slag outlet. Is done.

  By the way, in recent years, the influence on human bodies such as dioxins and heavy metals has been recognized, and even in such a melting furnace, there is a demand for an excellent maintainability such as reducing the number of times and time required for workers to work inside the furnace. Yes. However, in such a melting furnace, it is known that the tubular discharge passage is blocked due to adhesion of molten slag, etc., and maintenance work is performed to remove the deposits a predetermined number of times (or months). ing. Also, the inner wall of the melting furnace is usually made of the material as described above, so it is vulnerable to impact (easy to break), requires careful work to remove the adhering molten slag, and requires a long time for maintenance work. It has such a problem.

In order to solve such a problem, it is conceivable to suppress the adhesion of the molten slag to the inner wall of the tubular discharge passage, thereby reducing the number of operations for removing the molten slag and improving the maintainability. On the other hand, in Patent Document 1, a tubular discharge path is described as a protruding portion, and the upper end portion of the tubular discharge path is provided with a protruding portion that protrudes closer to the center than the inner peripheral edge. It is illustrated that the molten slag flows down at a location away from the inner wall of the discharge channel.
However, in such a melting furnace, since it has a protruding shape as described above, it is more easily cracked than the inner wall surface of the tubular discharge passage, and requires more careful handling. In addition, when such a protruding part is eroded by molten slag and needs repair, it is necessary to repair it by enormous man-hours of reworking the formwork after reworking the necessary part. It becomes. Therefore, conventional melting furnaces, such as gasification melting furnaces and ash melting furnaces, have a problem that it is difficult to reduce the number of maintenance operations and time, that is, to provide a melting furnace with excellent maintainability. is doing.

JP-A-6-11130

  The subject of this invention is providing the melting furnace excellent in maintainability in view of the said problem.

  In order to solve the above problems, the present invention is a gasification melting furnace for combustible materials in which ash is melted in a melting furnace after gasification of the combustible materials, and molten slag is discharged into the gasification melting furnace. The molten slag discharge port is opened, and a tubular discharge passage extending downward from the molten slag discharge port is provided, and the molten slag contacts the inner surface of the tubular discharge passage at the upper end of the tubular discharge passage. A protruding portion that protrudes inward from the inner peripheral edge of the tubular discharge passage is provided, and the protruding portion is detachably provided. A gasification melting furnace for combustible materials is provided.

  According to the present invention, the tubular discharge furnace of the melting furnace is provided with a protruding portion that protrudes inward from the inner peripheral edge of the tubular discharge passage at the upper end portion, so that it is more than the inner peripheral edge of the tubular discharge passage. The molten slag can flow down at a position closer to the center to prevent the molten slag from coming into contact with the inner surface of the tubular discharge passage, and the number of operations for removing the attached slag can be reduced. In addition, since the protruding portion is detachably provided, it is only necessary to remove slag adhering to the protruding portion or to replace the protruding portion with a new member when it is necessary to repair the protruding portion. Can be shortened. Therefore, the melting furnace can be made excellent in maintainability.

Hereinafter, a preferred embodiment of the present invention will be described with reference to FIG.
First, the gasification melting furnace 10 of this embodiment is demonstrated. In the gasification melting furnace 10 of the present embodiment, a combustible material is decomposed to produce combustible gas and ash, and combustible gas and ash are introduced from the gasification unit 2 and melted. The ash melting part 1 discharged as slag 3 is provided.

The ash melting part 1 is disposed below the furnace body part 4 to combust ash with combustible gas to form molten slag, and communicates with the furnace body part 4 to discharge the molten slag. And a molten slag discharge part 5 for performing
A slag cooling water tank 6 for cooling the molten slag to form a granulated slag is disposed below the molten slag discharge part 5.

  The furnace body 4 has a vertically long substantially cylindrical shape arranged in the vertical direction, and varies depending on the application, etc., but usually has an inner diameter of 1 to 3 m, refractory bricks such as silicon carbide and alumina, castable refractories, etc. The inner wall is constituted by the above, and the outer wall such as a steel plate is provided via a heat insulating member such as a heat-resistant brick. The furnace body 4 has an upper end closed and a lower end opened. Further, the upper end portion is provided with an ash supply port 41 for introducing ash together with a combustible gas and an auxiliary combustible gas such as air or oxygen, and the lower end portion is provided with a throttle structure 42 having a smaller diameter than the center portion, The molten slag discharge portion communicates with the squeezed structure 42.

  The molten slag discharge part 5 includes a bottom 51 inclined in a mortar shape, and is connected to the molten slag discharge port 52 opened at the lowermost part of the bottom surface 51, the molten slag discharge port 52, and the molten slag discharge port A tubular discharge passage 53 extending downward from the main body 4 is provided, and is formed in a substantially Y-shaped cross section by a member similar to the furnace body 4. In addition, an exhaust port 54 is formed at one upper end portion of the Y-shape so as to communicate with the furnace main body portion 4 and discharge the exhaust gas of the combustible gas burned in the furnace main body portion 4 at the other upper end portion. ing.

  The tubular discharge passage 53 is formed into a circular tube or a rectangular tube depending on the application, but is usually a circular tube having an inner diameter of 0.5 to 1.5 m and a length of 1.5 to 3.0 m, and has a lower end. The slag cooling water tank 6 is arranged so as to be immersed in water until it reaches a position of about 0.5 m from the water surface. Further, the upper end portion of the tubular discharge passage 53 is usually arranged so that the molten slag can flow down at a position closer to the center than the inner peripheral edge and the molten slag can be prevented from coming into contact with the inner surface of the tubular discharge passage 53 and flowing down. Further, a protruding portion 55 is provided that protrudes 5 to 10 cm inward from the inner peripheral edge of the tubular discharge passage 53. The protruding portion 55 is preferably formed by combining those divided into sizes that are easy to handle from the viewpoint that the maintainability of the melting furnace can be further improved. Furthermore, the divided pieces are easy to manufacture, and the divided pieces are the same because the troublesome work of attaching the specific divided pieces to specific places when replacing the divided pieces can be prevented. It is preferable to have the shape of

  An example of the case where the protruding portion is formed using a plurality of divided pieces will be described with reference to FIGS. 2 and 3. The upper end portion of the tubular discharge passage 53 has a thickness as a divided piece 56. Eight SUS304 stainless steel plates having a thickness of 10 to 60 mm are used to form protruding portions. The divided piece 56 collects the molten slag 3 and discharges it more quickly, and prevents the divided piece 56 from being eroded by the molten slag 3 or the slag solidifying and adhering to the divided piece 56. Since the replacement period of the piece 56 has an excellent point that can be extended, the two pieces are combined in a bowl shape with a V-shaped cross section and attached to the upper edge of the tubular discharge passage 53.

  As shown in FIG. 4, the split piece 56 can be attached by fitting an attachment hole 58 provided in the split piece 56 and an anchor pin 59 attached to the bottom surface 51 of the melting furnace. If necessary, the anchor pin 59 and the split piece 56 may be fixed by fixing means such as welding or screwing.

  In addition, necessary portions of the furnace body 4 and the molten slag discharge part 5 include internal observation windows made of heat-resistant glass, detection means such as various sensors, and control means for controlling the operation of the melting furnace based on the detection means. Etc. are provided as appropriate.

Next, the operation method of the gasification melting furnace 10 of the present embodiment will be described by taking as an example the case where combustible gas and ash are introduced from the gasification section 2 to form molten slag and discharged.
In the gasification part 2, combustible material is gasified and combustible gas, combustible solid content, and ash are generated. At this time, if necessary, it is possible to select a combustion condition in which a large amount of combustible solids such as char are produced from the gasification unit 2.
The ash discharged from the gasification unit 2 together with the combustible gas is accelerated by pressurized air and introduced into the ash melting unit 1 from the ash supply port. At this time, the ash is introduced so as to generate a swirl flow A in the furnace body so that the ash can stay in the furnace body longer.
In the furnace main body, the inside is normally kept at about 1300 ° C. by burning the introduced combustible gas. Then, the ash is melted while dropping the furnace body 4 while turning as described above. Further, the ash (molten slag 3) melted by the swirling flow A is attached to the inner wall of the furnace main body 4 and gathers on the wall surface to form a droplet.
By doing so, the molten slag is caused to flow down by its own weight, and is moved from the furnace body 4 to the molten slag discharge unit 5.

In the molten slag discharge part 5, the molten slag 3 flowed down from the furnace main body part 4 by the mortar-shaped bottom surface 51 is collected at the lowest part of the molten slag discharge part 5, and the molten slag discharge port opened at the lowermost part From 52, it passes through the tubular discharge passage 53 and flows down to the slag cooling water tank 6.
On the other hand, the exhaust gas of the combustible gas burned in the furnace body 4 is discharged from the exhaust port 54 opened in the molten slag discharge unit 5. Although not described in detail here, the exhaust gas can effectively use heat by a heat exchanger such as a boiler.

Further, by discharging the exhaust gas from the exhaust port 54, it is possible to suppress high-temperature exhaust gas from flowing into the tubular discharge passage 53, and the temperature of the atmosphere below the protruding portion 55 of the tubular discharge passage 53 is set to 1000 to 1200 ° C. Can be held to the extent.
Further, when the molten slag 3 is caused to flow from the molten slag discharge port 52 through the tubular discharge passage 53 and flow down to the slag cooling water tank 6, the molten slag 3 is melted by the protruding portion 55 provided at the upper end portion of the tubular discharge passage 53. The slag 3 is guided to the central portion of the tubular discharge passage 53 so as to flow down so as not to contact the wall surface of the tubular discharge passage 53.

Moreover, the molten slag which flowed down is thrown into the slag cooling water tank 6, and is carried out by the belt conveyor etc. as the granulated slag 3a.
When the protruding portion 55 is eroded by the molten slag 3 and the molten slag 3 may come into contact with the wall surface of the tubular discharge passage 53 and flow down, the divided piece 56 is removed from the anchor pin 59. Thus, the new protruding portion 55 can be formed quickly.
As described above, in this embodiment, since the operation state is stable, the maintenance time can be predicted, and the number of man-hours such as a special device for detecting the situation in the melting furnace and inspection work can be reduced. Since the gasification melting furnace which introduces combustible gas and ash from the gasification section and melts and slags and discharges it has been described because it has advantages, in the present invention, the melting furnace is limited to the gasification melting furnace Instead, an ash melting furnace that melts incombustibles, incineration residue, fly ash and other ash using plasma, arc, electric heater, fossil fuel, and the like is also within the intended scope of the present invention.

In this embodiment, it is strong against impact (low possibility of cracking), has excellent maintainability in that it does not require careful work, and contains chromium as compared with other metal materials such as carbon steel. It is possible to suppress erosion by molten slag because the heat resistance has been improved and the fact that it contains nickel and has high-temperature viscosity, and the number of replacements per unit period can be reduced. Although having the advantageous effect, the protruding portion is made of stainless steel, the protruding portion of the present invention is not limited to stainless steel as a forming material.
In the present embodiment, it is easy to procure members of various thicknesses and shapes, and processing means such as outer shape processing are generally established. From the point that it is possible to quickly respond to a sudden replacement request. The protruding portion is formed of stainless steel using SUS304. In this respect, the same effect can be obtained even if SUS310S, SUS316, or SUS316L is used.

  Further, in the present embodiment, it is possible to suppress the flow of high-temperature gas of the furnace main body into the tubular discharge passage, and to prevent untreated ash from adhering and accumulating on the inner wall of the tubular discharge passage, and From the point that the temperature of the protruding portion can be further lowered to suppress erosion due to molten slag, an exhaust port is provided above the protruding portion to discharge the gas in the furnace main body, but the melting furnace of the present invention However, the position of the exhaust port is not limited, and a structure in which no exhaust port is provided may be employed.

Further, when the protruding portion is formed of SUS304, SUS310S, SUS316, or SUS316L, the temperature of the atmosphere below the protruding portion is 1000 to 1200 ° C. by the exhaust port or the like. The effect of suppressing the portion from being eroded by the molten slag becomes more excellent.
In addition, it can confirm that the temperature of the atmosphere of the said convex part lower part has become 1000-1200 degreeC by the measurement using sheath thermocouples, such as Type K or Type R.

The fragmentary sectional view showing the gasification melting furnace of one embodiment. The top view which shows the protrusion part of the embodiment. The fragmentary sectional view which shows the X-X 'arrow cross section of FIG. a) Y-Y 'arrow sectional drawing of FIG. 3 which shows the attached split piece. b) Y-Y 'arrow sectional drawing of FIG. 3 which shows the removed piece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ash melting part 2 Gasification part 3 Molten slag 4 Furnace main-body part 5 Molten slag discharge part 10 Gasification melting furnace 52 Molten slag discharge port 53 Tubular discharge path 54 Exhaust port 55 Projection part

Claims (7)

A combustible material gasification and melting furnace for melting ash in a melting furnace after gasifying combustible material,
The gasification melting furnace is provided with a molten slag discharge port through which molten slag is discharged, and is provided with a tubular discharge passage extending downward from the molten slag discharge port. A protruding portion that protrudes inward from the inner peripheral edge of the tubular discharge passage is provided so that the molten slag can be prevented from coming into contact with the inner surface of the tubular discharge passage and flowing down; A combustible material gasification melting furnace, which is detachably provided. The combustible material gasification and melting furnace according to claim 1, wherein the protruding portion is made of stainless steel. The combustible gasification and melting furnace according to claim 2, further comprising an exhaust port through which exhaust gas is discharged, wherein the exhaust port is disposed above the protruding portion. The combustible gasification melting furnace according to claim 2 or 3, wherein the temperature of the atmosphere below the protruding portion is 1000 to 1200 ° C, and any one of SUS304, SUS316, SUS316L and SUS310S is used as the stainless steel. A melting furnace in which ash is melted and discharged as molten slag,
In the melting furnace, a molten slag discharge port through which molten slag is discharged is opened, and a tubular discharge passage extending downward from the molten slag discharge port is provided,
The upper end portion of the tubular discharge passage has a protruding portion protruding inward from the inner peripheral edge of the tubular discharge passage so as to suppress the molten slag from contacting and flowing down to the inner surface of the tubular discharge passage. A melting furnace characterized in that the protrusion is provided detachably. The melting furnace according to claim 5, wherein the protruding portion is made of stainless steel. The melting furnace according to claim 6, further comprising an exhaust port through which the gas from the molten slag discharge unit is discharged, wherein the exhaust port is disposed higher than the protruding portion.

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