JP2008082659A - Slag discharge device for melting furnace, and fluidized bed type gasification melting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a decrease in the cross-sectional area of a slag discharge part due to the sticking of slag with simple constitution. <P>SOLUTION: This slag discharge device comprises a slag discharge part 44 having an inner peripheral surface 45a circular from the top view; a chute 71 turnable around a vertical line L, passing the center of the inner peripheral surface 45a of the slag discharge part 44, serving as a rotation axis; a scraping member 73 fixed to the chute 71, with its tip 73a abutting on or close to the inner peripheral surface 45a of the slag discharge part 44; and a turning means 75 turning the chute 71. The chute 71 is turned by the turning means 75 to scrape the slag sticking to the inner peripheral surface 45a of the slag discharge part 44, with the tip 73a of the scraping member 73. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a slag discharger used in a fluidized bed gasification and melting system for treating waste such as municipal waste and industrial waste, and a fluidized bed gasification and melting system using the same.

  2. Description of the Related Art Conventionally, as a means for treating waste, a fluidized bed gasification melting system including a fluidized bed gasification furnace in which a fluidized bed is formed by a fluidizing gas and a subsequent melting furnace is known. The fluidized bed gasification furnace combusts the waste introduced into the fluidized bed to generate pyrolysis gas, and the melting furnace further generates the pyrolysis gas generated in the fluidized bed gasification furnace. Slag is produced by burning and melting the ash in the gas. Further, the melting furnace is provided with a slag discharge portion that forms a slag discharge port for discharging the generated slag, and the slag generated in the melting furnace is discharged from the slag discharge port.

  In such a fluidized bed gasification and melting system, when the slag is cooled while the slag adheres to the inner peripheral surface of the slag discharge part in the melting furnace due to fluctuations in the operation state, etc., Slag adheres to the inner peripheral surface. When the cooling of the slag as described above is repeated, a lump of slag that adheres to the inner peripheral surface of the slag discharge part gradually grows, and finally a slag discharge port formed inside the slag discharge part Blocked. Then, in order to prevent obstruction | occlusion of a slag discharge port, the slag removal apparatus which cleans the internal peripheral surface of a slag discharge part is proposed.

For example, in Patent Document 1 and Patent Document 2, slag removal is performed by removing a slag by reciprocating a cleaning rod by a driving means and pushing the slag adhering to the inner peripheral surface of the slag discharge portion with the cleaning rod. An apparatus is disclosed.
JP-A-9-222220 Japanese Patent Laid-Open No. 11-173767

  However, in the configuration in which the slag adhering to the inner peripheral surface of the slag discharge part protrudes with the cleaning rod, the inner peripheral surface can be cleaned only at one point, so the slag adheres to other parts and the cross-sectional area of the slag discharge port May be reduced and good slag discharge from the slag outlet may be impeded.

  In order to prevent the reduction of the cross-sectional area of the slag discharge port due to the slag sticking, it is possible to arrange a plurality of slag removal devices and clean the inner peripheral surface of the slag discharge part at a plurality of points. This is not preferable from the viewpoint of maintenance because it involves a significant increase in the number of parts.

  In view of such circumstances, the present invention provides a slag discharge device capable of preventing a reduction in the cross-sectional area of a slag discharge port due to slag fixation with a simple configuration, and a fluidized bed gasification and melting system using the same. The purpose is to do.

  The invention according to claim 1 is a slag discharge portion that is provided in a melting furnace that generates slag by burning and melting ash in pyrolysis gas of waste, and forms a slag discharge port for discharging the generated slag And a chute that is disposed below the slag discharge part and in which the slag discharged from the slag discharge port flows down, the slag discharge part has an inner peripheral surface that is circular in a plan view. The chute is connected to the slag discharge part so as to be rotatable about a vertical line passing through the center of the inner peripheral surface of the slag discharge part, and rotates the chute. The rotating means and the tip are fixed to the chute in a state where the tip is in contact with or close to the inner peripheral surface of the slag discharge portion, and the tip is attached to the inner peripheral surface of the slag discharge portion by rotating together with the chute. Scrape the slug A slag discharge device of the melting furnace, characterized in that it further comprises a scraping member that.

  According to this configuration, the scraping member is fixed to the chute in a state where the tip is in contact with or close to the inner peripheral surface of the slag discharge portion, and this chute rotates a vertical line passing through the center of the inner peripheral surface of the slag discharge portion. Since it rotates as a shaft, if the chute is rotated by the rotating means, the tip of the scraping member moves so as to slide on the inner peripheral surface of the slag discharge portion. Accordingly, the scraping member can scrape the slag adhering to the inner peripheral surface of the slag discharge portion over the entire circumference, preventing the slag from adhering to the inner peripheral surface of the slab discharge portion and forming the slab discharge portion. It is possible to prevent a reduction in the cross-sectional area of the slag discharge port. And the said effect can be acquired with the simple structure of rotating the chute | shoot which fixed the scraping member.

  The invention according to claim 2 is the slag discharge device for a melting furnace according to claim 1, wherein the scraping member has a shape extending linearly, and the scraping member is inserted into the chute from the outside. In this case, an insertion fixing part for fixing is provided.

  According to this configuration, since the insertion fixing portion for inserting and fixing the scraping member extending in a straight line from the outside to the chute is provided, when the scraping member is worn out, the scraping member can be easily Can be replaced.

  According to a third aspect of the present invention, in the slag discharge device for a melting furnace according to the first or second aspect, the slag discharge portion is provided with a bulge portion projecting inwardly at an upper end portion. The inner peripheral surface having a circular shape in plan view is constituted by the tip.

  According to this structure, since the overhang | projection part is provided in the upper end part of the slag discharge part, slag flows down from the front-end | tip of this overhang | projection part. That is, the portion to which the slag adheres is only the inner peripheral surface constituted by the tip of the overhanging portion, and the area of the portion to which the slag adheres can be kept small. And since the inner peripheral surface having a circular shape in plan view is constituted by the tip of the overhanging portion, the tip of the scraping member comes into contact with or is close to the inner peripheral surface having a small area, The slag adhering to the surface can be scraped off with a relatively small force.

  According to a fourth aspect of the present invention, there is provided a fluidized bed type gasification furnace for forming a fluidized bed by supplying a fluidized gas to a fluidized medium, and gasifying waste supplied to the fluidized bed, and the fluidized bed type. The melting furnace according to any one of claims 1 to 3, wherein the melting furnace generates slag by burning the combustible component in the pyrolysis gas generated in the gasification furnace and melting the ash in the gas. A slag discharge device for the furnace, and a slag cooling device for cooling the slag discharged from the slag discharge port of the slag discharge device, and a chute of the slag discharge device is disposed between the melting furnace and the slag cooling device. A fluidized bed gasification and melting system characterized in that it is disposed.

  For example, a fluidized bed gasification melting system may be configured by arranging a chute of a slag discharge device between a melting furnace and a slag cooling device as in the invention according to claim 4.

  As described above, according to the present invention, it is possible to prevent a reduction in the cross-sectional area of the slag discharge portion due to the fixation of the slag with a simple configuration.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows the overall configuration of a waste treatment facility equipped with a fluidized bed gasification and melting system according to an embodiment of the present invention. In addition, in application of this invention, it does not ask | require in particular about the whole structure of the waste treatment facility in which a fluidized bed type gasification melting system is introduced.

  In FIG. 1, waste as waste is temporarily stored in a waste pit 1 and is put into a hopper 2a of a dust feeder 2 by a crane (not shown). The dust feeder 2 supplies the waste to the fluidized bed gasifier 3 quantitatively.

  In the fluidized bed gasification furnace 3, for example, partial combustion is performed under the condition of an air ratio of 0.2 to 0.4, and thermal decomposition, that is, gasification, is performed with the temperature of the fluidized bed formed of a sand layer or the like maintained at 450 to 650 ° C. The fluidized bed is formed above the dispersion plate 31 by, for example, injecting fluidized gas upward from a gas injection port of the dispersion plate 31 provided at the bottom of the fluidized bed gasification furnace 3. The incombustible material out of the thrown-in waste is withdrawn from the bottom of the hearth and separated into non-combustible material, non-ferrous metal, iron, and fluidized sand through the screw conveyor 5, vibration feeder 6 and magnetic separator (not shown). The fluidized sand is returned to the sand layer of the fluidized bed gasifier 3 and reused.

  The pyrolysis gas generated in the fluidized bed gasification furnace 3 is guided to the melting furnace 4 and further combusted under the condition of a total air ratio of 1.3, for example. In this melting furnace 4, a swirl flow is formed and high temperature combustion at about 1300 ° C. is performed, and the ash in the pyrolysis gas is melted and separated as slag by the heat, and harmful substances in the gas such as dioxin Is disassembled.

  More specifically, the melting furnace 4 is configured such that the inside is covered with a refractory, and includes a melting part 41 that extends vertically and has a burner 40 at the top, and that extends vertically next to the melting part 41. The secondary combustion part 42 and the slag separation part 43 which connects the lower part of the fusion | melting part 41 and the secondary combustion part 42 are provided. The pyrolysis gas introduced to the melting furnace 4 is first combusted in the melting part 41, and then introduced into the secondary combustion part 42 through the slag separation part 43, where it is combusted again.

  The slag separator 43 is formed in a shape that inclines downward as it goes inward from both ends, and a slag discharge device 7 is connected to the lower end of the slag separator 43. Specifically, the slag discharge device 7 has a slag discharge portion 44 that forms a slag discharge port 44a (see FIG. 2) for discharging slag from the melting furnace 4, and this slag discharge portion 44 is the slag discharge portion 44. It is provided at the lower end of the separation part 43. When the pyrolysis gas is burned in the melting part 41 and the secondary combustion part 42, the ash in the gas melts and adheres to the furnace wall as slag. The slag adhering to the furnace wall of the melting part 41 and the secondary combustion part 42 flows down along the furnace wall under its own weight, and is separated from the gas flow by the slag separation part 43 as shown by an arrow in FIG. It is discharged out of the furnace through the outlet 44a.

  The slag discharged from the slag discharge port 44a passes through the chute 71 of the slag discharge device 7 and flows down to the slag cooling device 8, where it is rapidly cooled and becomes granular. And the granular slag is carried out from the slag cooling device 8 with the conveyor etc. which are not shown in figure.

  The melting furnace exhaust gas discharged from the melting furnace 4 passes through the air heater 9 and the waste heat boiler 10, where the heat in the gas is recovered. Further, the exhaust gas is cooled by the gas cooler 11 and dust is removed by the bag filter 12. The exhaust gas thus purified passes through the induction fan 13, passes through the denitration device 14, and is discharged from the chimney 15.

  The fluidized bed gasification furnace 3, the melting furnace 4, the slag discharge device 7, and the slag cooling device 8 constitute a fluidized bed gasification melting system.

  Next, the slag discharge device 7 including the slag discharge portion 44 and the chute 71 will be described in detail with reference to FIGS.

  The slag discharge part 44 is configured to be covered with a refractory inside, and is formed in a circular cylindrical shape extending vertically, and communicates the inside and outside of the melting furnace 4 with the inner peripheral surface thereof. A slag discharge port 44a is formed. Further, a ring-shaped projecting portion 45 projecting inward over the entire circumference is provided at the upper end portion of the slag discharge portion 44. The protruding amount of the protruding portion 45 is set uniformly over the entire circumference, and the tip of the protruding portion 45 has an inner peripheral surface 45a that is concentric with the outer peripheral surface of the slag discharge portion 44 in plan view. It is composed. Further, the lower surface of the overhanging portion 45 is parallel to the horizontal plane, while the upper surface is inclined so as to form a wall surface continuous with the inner surface of the slag separating portion 43. For this reason, the slag separated from the gas flow by the slag separation part 43 as shown by a thick line in FIG. 2 smoothly passes over the upper surface of the overhanging part 45 and flows down from the tip of the overhanging part 45. Note that the slag may flow into the slag discharge portion 44 not only from the left-right direction in FIG. 2 but also from other directions.

  The chute 71 is formed in a vertically extending circular cylinder having an outer diameter substantially the same as the outer diameter of the slag discharge portion 44, the upper end portion is connected to the lower end portion of the slag discharge portion 44, and the lower portion is the It enters into the water tank 81 of the slag cooling device 8. Water is stored in the water tank 81 until the lower end of the chute 71 is immersed, thereby preventing the flow of pyrolysis gas to the outside through the slag discharge port 44a. Further, the chute 71 is supported by a pedestal 77 disposed so as to cover the slag cooling device 8 in a state where the central axis thereof coincides with the central axis of the slag discharge portion 44.

  More specifically, the chute 71 is divided into two, an upper chute 71A and a lower chute 71B, at a position above the upper surface of the mount 77. The upper chute 71 </ b> A is covered with a refractory, and the lower chute 71 </ b> B is not covered with a refractory, and the steel peripheral wall is also exposed inside. The lower end of the upper chute 71A and the upper end of the lower chute 71B are flange-coupled.

  Further, the total thickness of the upper chute 71A is set smaller than the total thickness of the slag discharge part 44. For this reason, the slag flowing down from the tip of the overhanging portion 45 passes through the chute 71 without contacting the upper chute 71 </ b> A and falls into the water tank 81 of the slag cooling device 8.

  As shown in FIG. 5, the details of the connecting portion between the chute 71 and the slag discharge portion 44 are such that the flange portions provided on both sides are in surface contact with each other so that they can slide. Further, the refractory material of the upper chute 71A is held down, and the refractory material of the slag discharge portion 44 enters the portion so that the space between them is sealed. It is also possible to seal between the slag discharge part 44 and the upper chute 71A, for example, by supplying air or arranging packing. Alternatively, the flange portions may be merely brought into surface contact.

  A collar portion 74 is provided at the lower portion of the upper chute 71A. A wheel 76b is attached to the lower surface of the flange portion 74 at an appropriate position, and a rail 76a for guiding the wheel 76b is provided on the upper surface of the mount 77. Then, the wheel 76b is guided by the rail 76a, so that the chute 71 in which the upper chute 71A and the lower chute 71B are integrated can rotate as indicated by an arrow b in FIG. It has become. In other words, since the central axis of the chute 71 coincides with the central axis of the slag discharge part 44 as described above, the chute 71 rotates about the vertical line L passing through the center of the inner peripheral surface 45a. To do.

  A ring gear 75c is attached to the tip of the flange 74, while a reduction gear drive motor 75a is attached to the output surface of the pinion 75b that meshes with the ring gear 75c. Is arranged. That is, the drive motor 75a with a speed reducer, the pinion 75b, and the ring gear 75c constitute a rotating means 75 that rotates the chute 71.

  The reduction ratio of the drive motor 75a with a reduction gear and the number of teeth of the pinion 75b and the ring gear 75c are determined so that the chute 71 can be rotated at a rotational speed of 0.5 to 6 rotations / hour. The speed reducer-equipped drive motor 75a can change the number of rotations according to the operating state by an unillustrated inverter or the like.

  Further, the upper chute 71A is provided with an insertion fixing portion 72 for inserting and fixing a scraping member 73 described later from the outside. The insertion fixing portion 72 is provided on the outer chute 71A so as to extend through the through hole 72a penetrating the upper chute 71A at a predetermined angle inclined downward in the radial direction. It has a cylindrical section 72b having a circular cross section. Further, a flange portion is provided at the tip of the cylindrical portion 72b, although not shown.

  As shown in FIGS. 6A and 6B, the scraping member 73 has a circular bar shape extending linearly, and the insertion fixing portion 72 is indicated by an arrow a in FIG. It can be inserted and removed from inside. The scraping member 73 is for scraping the slag adhering to the inner peripheral surface 45a constituted by the tip of the overhanging portion 45 of the slag discharge portion 44 at the tip 73a, and has a diameter of, for example, 10 to 80 mm. Have. Note that the cross-sectional shape of the scraping member 73 does not have to be circular, and may be, for example, a square or a polygon. The scraping member 73 is preferably hollow, but may be solid.

  A flange portion 73b is provided at the end of the scraping member 73 opposite to the tip 73a. The flange portion 73b is fastened to the flange portion at the tip of the cylindrical portion 72b with bolts and nuts. When the flange portion 73b is fastened to the flange portion of the cylindrical portion 72b, the scraping member The scraping member 73 is fixed to the insertion fixing portion 72 in a state where the tip 73a of the 73 is in contact with or close to the inner peripheral surface 45a of the slag discharge portion 44.

  When the chute 71 is rotated by the rotation means 75, the scraping member 73 rotates together with the chute 71. At this time, since the chute 71 rotates about the vertical line L passing through the center of the inner peripheral surface 45a as the rotation axis, the tip 73a of the scraping member 73 slides on the inner peripheral surface 45a. Moving. Thereby, the slag adhering to the said inner peripheral surface 45a is scraped off over the perimeter by the scraping member 73. FIG.

  Thus, in the slag discharge device 7 in the present embodiment, the slag adhering to the inner peripheral surface 45a of the slag discharge portion 44 can be scraped over the entire circumference by the scraping member 73, so that the inner peripheral surface 45a can be scraped off. It is possible to prevent the slag from adhering and prevent the cross-sectional area of the slag discharge port 44a from decreasing. In addition, the above effect can be obtained with a simple configuration in which the chute 71 to which the scraping member 73 is fixed is rotated.

  Further, since the chute 71 is provided with an insertion fixing portion 72 for inserting and fixing the scraping member 73 having a linearly extending shape from the outside, when the scraping member 73 is worn, the worn scraping is removed. The scraping member 73 can be easily replaced from the outside by inserting the new scraping member 73 straightly into the insertion fixing portion 72 after the member 73 is straightly extracted from the insertion fixing portion 72.

  Further, an overhanging portion 45 is provided at the upper end of the slag discharge portion 44, and the slag flows down from the tip of the overhanging portion 45, so the portion where the slag adheres is the tip of the overhanging portion 45. Only the inner peripheral surface 45a is configured, and the area of the portion where the slag adheres can be reduced. And since the front-end | tip 73a of the scraping member 73 contact | abuts or adjoins to the internal peripheral surface 45a with this small area, it can scrape off the slag adhering to the internal peripheral surface 45a with a comparatively small force. become able to.

  In the above embodiment, the slag discharge part 44 is provided with the overhanging part 45, but the overhanging part 45 can be omitted. In this case, the tip 73a of the scraping member 73 may be brought into contact with or close to the upper end portion of the inner peripheral surface of the slag discharge portion 44 where slag lump is easily formed. Alternatively, the tip 73a of the scraping member 73 may have a cross-sectional shape that extends vertically, and the inner peripheral surface of the slag discharge portion 44 may be scraped over a wide area.

  Moreover, in the said embodiment, although the slag discharge | emission part 44 becomes circular cylinder shape, the slag discharge | emission part 44 should just have the internal peripheral surface which makes circular shape by planar view at least partially, for example, the said In the embodiment, the portion other than the inner peripheral surface 45a constituted by the tip of the overhanging portion 45 may be, for example, a rectangular cylinder. The chute 71 is only required to be rotatable about a vertical line passing through the center of the inner peripheral surface having a circular shape in plan view of the slag discharge portion 44. The shape of the chute 71 is, for example, a rectangular cylinder or the like It may be.

  Further, the scraping member 73 does not necessarily have a shape extending linearly, and may be formed in, for example, a curved or bent shape. However, in this case, when fixing the scraping member 73 to the insertion fixing portion 72, the tip 73 a of the scraping member 73 is brought into contact with the inner peripheral surface 45 a of the slag discharge portion 44 unless the circumferential position is determined. Alternatively, if the scraping member 73 has a shape extending linearly as in the above-described embodiment, the tip 73a is simply fixed to the insertion fixing portion 72 and the tip 73a thereof is slag discharging portion 44. Can be brought into contact with or close to the inner peripheral surface 45a.

  Further, as shown in FIGS. 7A and 7B, the scraping member 71 has a double pipe structure in which the inner cylinder is covered with the outer cylinder, and is provided with an inlet 73c and an outlet 73d. You may make it flow cooling water in the taking member 71. FIG. By doing so, the life of the scraping member 71 can be extended.

  Further, in order to support the chute 71 so as to be rotatable, a thrust bearing or the like may be employed instead of the wheel 76b and the rail 76a. Moreover, as a rotation means for rotating the chute 71, for example, a chain or a belt may be used.

  Furthermore, in the above embodiment, the upper chute 71A and the lower chute 71B are flange-coupled so as to rotate together, but the lower chute 71B is attached to the gantry 77 or the slag cooling device 8. The upper chute 71A and the lower chute 71B may not be fastened to each other by bolts and nuts, but may be filled with lubricating oil to rotate only the upper chute 71A. .

1 is an overall configuration diagram of a waste treatment facility including a fluidized bed gasification and melting system according to an embodiment of the present invention. It is sectional drawing of the slag discharge | emission part vicinity of the melting furnace in the said fluidized bed type gasification melting system. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a figure which shows the detail of the junction part of the said slag discharge part and the chute | shoot of a slag discharge apparatus. It is a figure which shows the scraping member of the said slag discharge device, (a) is a side view, (b) is a rear view. It is a figure which shows the scraping member of a modification, (a) is a side view, (b) is a rear view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Fluidized bed type gasifier 4 Melting furnace 44 Slag discharge part 44a Slag discharge port 45 Overhang part 45a Inner peripheral surface 7 Slag discharge apparatus 71 Chute 72 Insertion fixing part 73 Scraping member 75 Turning means 8 Slag cooling apparatus L Vertical line

Claims (4)

A slag discharge part that is provided in a melting furnace that generates slag by burning and melting ash in the pyrolysis gas of waste, and forms a slag discharge port for discharging the generated slag, and below this slag discharge part The slag discharged from the slag discharge port is provided with a chute that flows down inside,
The slag discharge part has an inner peripheral surface that is circular in a plan view, and the chute is rotatable about a vertical line passing through the center of the inner peripheral surface of the slag discharge part. Connected to the slag discharge part,
Rotating means for rotating the chute, and the slag discharging portion at the tip by being fixed to the chute in a state where the tip is in contact with or close to the inner peripheral surface of the slag discharging portion and rotating together with the chute And a scraping member for scraping off the slag adhering to the inner peripheral surface of the melting furnace.   2. The scraping member has a shape extending linearly, and the chute is provided with an insertion fixing portion for inserting and fixing the scraping member from the outside. The slag discharge device of the melting furnace as described in 2.   The slag discharge portion is provided with an overhanging portion that protrudes inwardly at an upper end portion, and the inner peripheral surface that forms a circular shape in a plan view is constituted by the tip of the overhanging portion. Item 3. A slag discharge device for a melting furnace according to Item 1 or 2.   A fluidized bed is formed by supplying a fluidized gas to a fluidized medium, and waste generated in the fluidized bed is gasified, and heat generated by the fluidized bed gasifier. The melting furnace which produces | generates slag by burning the combustible component in cracked gas, and fuse | melting the ash in the gas, The slag discharge | emission apparatus of the melting furnace of any one of Claims 1-3, A slag cooling device that cools the slag discharged from the slag discharge port of the slag discharge device, and a chute of the slag discharge device is interposed between the melting furnace and the slag cooling device Floor type gasification melting system.

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