JP4104348B2 - Slag guide structure in melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a slag guide structure for a melting furnace provided with slag guide means for naturally flowing molten slag obtained by melting incineration ash from a melting chamber to a discharge chamber.
[0002]
[Prior art]
When municipal waste and sewage sludge are incinerated, the main ash, which is the burner, and the fly ash accompanying the exhaust gas are discharged. These incineration ash contains harmful substances such as precious metals and chlorides. For this reason, electric melting furnaces, surface melting furnaces, and the like are used as melting furnaces that reduce the amount of incinerated ash as molten slag and render it harmless.
[0003]
As one of such melting furnaces, Japanese Patent Laid-Open No. 3-91609 discloses an “ash melt-solidifying apparatus”. The melting furnace used in this processing apparatus is a swirling flow melting furnace, which has a melting part that turns into molten slag while swirling fly ash in the upper part, and a tapping part that discharges molten slag in the lower part. A funnel part for collecting and pouring the molten slag flowing down is disposed between the part and the brewing part, and a conveying means for conveying the molten slag is provided below the brewing part.
[0004]
The funnel portion is formed as a ridge of a V-shaped groove for discharging the molten slag, and is provided with an inclination. By making it a V-shaped groove, it is easy to collect molten slag, and by inclining, even if semi-molten slag that is not completely melted is mixed, it can be made to flow stably. In addition, the tip of the funnel part is provided so as to protrude from the furnace wall of the melting furnace, preventing the molten slag from flowing down along the furnace wall, thereby solidifying the molten slag when it travels along the furnace wall. This prevents the blockage.
[0005]
The funnel portion is exposed to a temperature substantially equal to or higher than the furnace wall of the melting furnace, and therefore needs to have heat resistance and fire resistance equivalent to those of the furnace wall. Ceramic refractories are known as materials used for the furnace wall, but since a large amount of molten slag flows down the upper surface of the funnel, ceramic refractories are subject to severe erosion and must be replaced in a short time. The For this reason, Japanese Patent Application Laid-Open No. 6-170353, which proposes an improved invention of the processing apparatus of the above-mentioned patent publication, proposes to use a chromium alloy having excellent corrosion resistance as the material of the funnel.
[0006]
In the processing apparatus of the second publication, it has also been proposed to form a funnel portion by combining a plurality of blocks. In the figure, there is shown a funnel portion in which three bottom plate blocks and two side wall blocks placed on the bottom plate and spaced apart from each other are combined. The shape of each block is a quadrangular prism.
[0007]
[Problems to be solved by the invention]
By the way, the funnel part made of a chromium alloy proposed in the second patent publication is excellent in corrosion resistance against molten slag, so that it can be used for a longer time than the funnel part made of ceramic refractory. is there. However, the funnel portion according to this publication has the following new problems.
[0008]
The funnel part is formed by combining square block blocks, and if the block is a square column, the shape is simple, so it is difficult for thermal stress to concentrate and the possibility of cracking is very small. The flow of the molten slag is not stable because the flow path is a square groove and there is no side wall block at the tip. The V-shaped groove is superior in that the flow is stable.
[0009]
Therefore, it is conceivable that the funnel portion is a V-shaped groove funnel portion and made of a chromium alloy. The funnel portion made of a chrome alloy can be used for a long time, but if it is used for a long time, there is a risk that cracks will eventually occur because it repeatedly receives a thermal shock or the like due to the temperature rise and fall of the melting furnace. In particular, when a funnel portion having a V-shaped groove is integrally manufactured as a chromium alloy, cracks are likely to occur at the bottom of the groove.
[0010]
This crack at the bottom tends to occur from the tip of the funnel. This is because the tip portion of the funnel portion protrudes from the furnace wall, and the lower portion of the funnel portion cannot be protected (supported) by a refractory material at the tip portion. Moreover, if the cooling pipe is embedded in the refractory, the funnel can be prevented from becoming hot, but cannot be suppressed at the exposed tip. And once a crack occurs, the crack gradually expands, and the molten slag flows down from the cracked part and travels down the furnace wall, so that the molten slag solidifies at the furnace wall part and causes clogging. .
[0011]
Moreover, if the funnel portion is formed of two members, the split surface is likely to open. Although the slag falls from the tip of the split member, even if the tip is extended from the side wall so that the slag does not adhere to the side wall of the discharge chamber, if the split surface opens, the side wall is removed from the open part. It will be transmitted and flow down.
[0012]
In consideration of the above problems, the present invention has a flow path for flowing the molten slag from the melting chamber to the discharge chamber, and has a shape that is excellent in flow characteristics with a material having high corrosion resistance at high temperature and is less likely to crack. It is an object of the present invention to provide a melting furnace that can be used stably for a long period of time by preventing the slag guide means from opening between the two split members.
[0013]
Another object of the present invention is to provide a melting furnace that can meet the above-mentioned problems and can be easily removed when the slag guide means is repaired.
[0014]
[Means for Solving the Problems]
As a means for solving the above-mentioned problems, the present invention is provided between a melting chamber that melts incinerated ash at a high temperature to form molten slag, and a discharge chamber that discharges molten slag along with combustion exhaust gas generated at the side of the molten slag. The slag guide means for naturally flowing the molten slag from the melting chamber to the discharge chamber is interposed between the two chambers, and the slag guide means is formed by combining symmetrical chromium alloy blocks. The left and right chrome alloy blocks of this slag guide means are mounted, and a grooved rod-like block that engages the lower portions of both blocks to prevent the blocks from opening is provided. This is a slag guide structure in the melting furnace.
[0015]
In the melting furnace having the above-described configuration, the incineration ash is melted in the melting chamber in the same manner as in the past to form molten slag. The molten slag stays in the molten pool chamber below the melting chamber, then flows down to the discharge chamber through the slag guide means, and further, a recovery process is performed below the molten slag. Since the slag guide means is formed of a chromium alloy block, it has high corrosion resistance at high temperatures. Further, the blocks are combined symmetrically so that a V-shaped groove is formed.
[0016]
For this reason, even if the slag guide means receives a thermal shock or the like due to the rising / lowering temperature, the bottom of the V-shaped groove is provided with a crack by assembling a block in advance, so that no further cracks occur, and V Since the letter-shaped groove has excellent flow characteristics with respect to the molten slag, the molten slag flows smoothly into the discharge chamber.
[0017]
However, when the slag guide means is formed of two blocks, the split surface is likely to open. Therefore, in the present invention, a grooved bar block is provided to prevent the opening, and a chrome alloy block is formed on the block. The lower part is engaged, thereby preventing the blocks from opening.
[0018]
Embodiment
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a melting furnace according to an embodiment. The illustrated melting furnace 1 is a swirl type melting furnace, and includes an upper swirl melting chamber 2 and a lower melting pool chamber 3, in which the molten slag is dropped into the molten pool chamber 3 while swirling. As shown in the figure, the swirl melting chamber 2 has an oval hollow cross-sectional shape, and an air introduction pipe 5 is connected to the upper part thereof. An incineration ash supply pipe 6 and a main burner 7 are attached to the air introduction pipe 5.
[0019]
High-temperature air is sent into the air introduction pipe 5, and incineration ash generated in an incinerator (not shown) or the like is sent into the supply pipe 6. The main burner 7 includes a vertically downward fuel injection pipe 8, and a vane 9 is attached in the vicinity of the outlet of the air introduction pipe 5 at the tip of the main burner 7 to the melting chamber 2. A swirling flow is generated in the melting chamber 2. Further, an ignition burner 10 is provided at a position above the melting chamber 2 so as not to interfere with the air introduction pipe 5.
[0020]
The swirl melting chamber 2 is connected to the molten pool chamber 3 through an opening at the bottom thereof, and a discharge chamber 11 is connected to a side portion of the molten pool chamber 3. Inside the molten pool chamber 3, a flank 12 is provided as a slag guide means for naturally flowing down and discharging the molten slag. Reference numeral 13 denotes a shielding wall provided in the molten pool chamber 3 for preventing the molten slag from flowing down. The discharge chamber 11 discharges molten slag together with combustion exhaust gas generated at the time of melting. An exhaust gas outlet 14 is provided at the side of the discharge chamber 11 and a chute 15 is provided below the chute 15 for passing the molten slag. It is sealed with water.
[0021]
As shown in FIGS. 2 and 3, a heat insulating material 21, a primary refractory material 22, and a secondary refractory material 23 are disposed on the inner surface of the molten pool chamber 3. Reference numeral 20 denotes a cooling pipe. The secondary refractory material 23 is applied to the same level as the bottom of the V-shaped groove 18 on the upstream side of the periphery of the reed 12, and is applied to the upper surface of the reed 12 in the section of the distance L on the side of the reed 12.
[0022]
As shown in the figure, the cage 12 provided in the molten pool chamber 3 is inclined at the boundary corner between the molten pool chamber 3 and the discharge chamber 11 and has a lower end protruding from the furnace wall of the discharge chamber 11. It has been. The flange 12 is made of a chromium alloy, and as shown in FIG. 2, is formed by combining a symmetrical alloy block 17 to form a substantially V-shaped groove 18. The cross-section of the flange 12 is Y-shaped, ensuring a large distance from the bottom of the V-shaped groove to the lower end of the flange 12, preventing leakage of molten slag from the mating surfaces of the left and right alloy blocks 17, 17, and The deformation | transformation by protruding from the primary refractory material 22 is prevented.
[0023]
The trough 12 is locked by a bar-shaped block 26 with a groove 26 a below it, and the bar-shaped block 26 with a groove is fixed to the primary refractory material 22. As shown in FIG. 5 (a), the grooved rod-shaped block 26 has a U-shaped cross section, and the lower portion of the flange 12 is fitted into the groove 26a, and the alloy blocks 17 and 17 are the joint surfaces. I try to prevent it from opening. The grooved rod-shaped block 26 is provided at a downstream position of the corner of the primary refractory material 22 as shown in FIG.
[0024]
The flange 12 is locked by another rod-like block (projection body) 19 provided on the upstream side of the grooved rod-like block 26 below, and the rod-like block 19 is shown in FIG. 5 (b). The cross section is rectangular and is fixed to the primary refractory material 22. As shown in FIG. 4, grooves 17 a that engage with the rod-shaped blocks 19 are formed in the alloy blocks 17 and 17. The rod-shaped block 19 is connected to the cooling pipe 20 provided inside the primary refractory material 22 via a connecting member 32. In this case, since the rod-shaped block 19 and the flange 12 are merely fitted and not integrated, cooling (thermal conduction) to the flange 12 is good and thermal shock increases, but there is a risk of inducing cracking of the flange 12. There is no.
[0025]
In consideration of the corrosion resistance of the molten slag, it is necessary that the chromium alloy material of the ridge 12 contains 50% by weight or more, preferably about 60% by weight of chromium in the composition. As a composition other than chromium, it is desirable to include a strengthening element such as W, Nb, or Ti.
[0026]
The incinerated ash is melted as follows and processed as molten slag by the melting furnace of the embodiment having the above-described configuration, and the basic operation as the melting furnace is the same as the conventional one and will be briefly described. When the incineration ash is supplied from the supply pipe 6 to the air introduction pipe 5, it is fed into the melting chamber 2 together with high-temperature heated air, ignited by the ignition burner 10, and then incinerated ash with the fuel from the fuel injection pipe 8 of the main burner 7. Is melted in the melting chamber 2 while being swirled and turned into a molten slag.
[0027]
Although the molten molten slag falls into the molten pool chamber 3, the molten slag stays in the molten pool chamber 3 for a while since the molten pool chamber 3 is provided with a shielding wall 13 that prevents the molten slag from flowing down. . For this reason, even if the molten slag in a semi-molten state is mixed, the molten slag is completely melted and then passes through both sides of the shielding wall 13 to reach the trough 12.
[0028]
Since the trough 12 has a V-shaped groove and is provided in an inclined shape, the flow characteristic is extremely excellent, and the molten slag flows smoothly and falls into the discharge chamber 11. In the flange 12, the V-shaped groove is formed by the left and right alloy blocks 17, and a crack is made in advance at the bottom of the groove. Moreover, the heel 12 is made of a chromium alloy having excellent corrosion resistance, and both sides are surrounded by the secondary refractory material 23, so that thermal deformation due to thermal shock is small and it can be used stably for a long time. it can.
[0029]
Furthermore, since the lower part of the flange 12 is fitted by the grooved rod-shaped block 26, the joint surfaces of the alloy blocks 17 and 17 are prevented from opening each other, and the joint surface does not open even after long-term use. Molten slag does not flow down. Further, since the bar 12 is locked by the other bar-shaped block 19, the bar 12 does not move.
[0030]
FIG. 6 shows a partial modification of the ridge 12. 2 and 3 is the same as the saddle 12 shown in FIGS. 2 and 3 except that the saddle 12x is composed of symmetrical alloy blocks 17x and 17x. It differs in that it is formed. Therefore, in the case of this modification, it is a premise that a concave portion into which the protruding portion 17p is fitted is formed on the upper surface of the primary refractory material 22. The grooved rod-shaped block 26 is the same as that in the above-described embodiment.
[0031]
FIG. 7 is another partial modification of the ridge 12. The saddle 12y is also composed of symmetrical alloy blocks 17y and 17y in the same way as the saddle 12 of FIGS. 2 and 3, but the V-shaped groove is partially different. As shown in the figure, the V-shaped groove of the base 24b is an acute-angled V-shaped groove, but the V-shaped groove of the end 25b is formed as a U-shaped groove whose bottom half is rounded, and the base 24b and the end At the boundary position of 25b, a step is provided in each V-shaped groove, and a groove liner 28 having a substantially arc-shaped cross section and a flat upper surface is inserted on the U-shaped groove of the end portion 25b, and the upper surface is V of the base portion 24b. It coincides with the bottom of the groove.
[0032]
By using the groove liner 28, the flange 12y formed as described above can almost completely prevent the molten slag from leaking from the center mating surface of the end portion 25b. In this case, if the groove liner 28 is also made of a chromium alloy material like the blocks 17y, the end portion 25b can be prevented from being melted and can be used stably for a long time.
[0033]
FIG. 8 shows still another partial modification of the ridge 12. 2 and 3 is the same as the flange 12 in FIGS. 2 and 3, but the outer surfaces of the alloy blocks 17z and 17z are formed in a smooth and smooth shape. The point provided with the convex portion 17q is partially different. As shown in the drawing, the cross section is substantially Y-shaped, but the bent portion is smoothly curved, and thus the V-shaped groove is also smoothly spread. Although the convex part 17q of the up-down direction is provided in the outer surface of the block, this need not necessarily be provided.
[0034]
The partially modified scissors 12z are easy to replace when it is necessary to replace them due to melting damage. The scissors 12z are used with a refractory material cast on the outer surface, but need to be replaced due to melting after long-term use.
[0035]
Therefore, in this case, if the eaves 12z are to be pulled upward, the outer surface is smooth, so that it can be easily separated from the refractory material and can be easily replaced. As shown in the figure, the vertical surface 17q is provided on the outer surface, but it does not matter as long as it does not cause a major obstacle to removal. In addition, it is desirable to form the Y-shaped cross section so that the width W of the flange 12z becomes narrower toward the lower side.
[0036]
【The invention's effect】
As described above in detail, the melting furnace of the present invention is provided with slag guide means in the flow path for naturally flowing the molten slag melted in the melting chamber to the discharge chamber arranged on the side of the melting chamber. In combination with the left and right symmetrical chrome alloy blocks to form a substantially V-shaped groove, a grooved rod-shaped block is provided to engage the lower portions of both blocks to prevent the opening of both blocks. By the slag guide means of the V-shaped groove in which cracks are formed on the surfaces where the blocks contact each other, the molten slag can flow smoothly, and even if used for a long period of time, there will be no further cracks. There is a remarkable effect that it is possible to obtain a melting furnace that can be used stably for a long period of time by preventing the opening between the two split members.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a melting furnace according to an embodiment. FIG. 2 is a sectional view in the vicinity of the slag guiding means. FIG. 3 (a) is a sectional view of the slag guiding means as viewed from an arrow IIIa in FIG. b) Sectional view as seen from arrow IIIb in FIG. 2 [FIG. 4] (a) Side view of slag guiding means, (b) Front view [FIG. 5] (a) Enlarged view of grooved bar block, (b) FIG. 6 is a side view of a modified example of the slag guide means. FIG. 7 is a perspective view of another modified example of the slag guide means. FIG. 8A is a modified example of the slag guide means. Front view, (b) Perspective view [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Melting furnace 2 Swirling melting chamber 3 Melting pool chamber 4 Melting chamber 5 Air introduction pipe 6 Supply pipe 7 Main burner 8 Fuel injection pipe 9 Vane 10 Ignition burner 11 Discharge chamber 12 樋 13 Shielding wall 14 Exhaust gas outlet 15 Chute 16 Slag pit 17 Alloy block 17a Groove 18 V-shaped groove 19 Bar-shaped block 20 Cooling pipe 21 Heat insulating material 22 Primary refractory material 23 Secondary refractory material 24 Base portion 25 End portion 26 Grooved rod-shaped block 28 Groove liner

Claims (5)

   The molten slag is melted from the melting chamber 2 by interposing between the melting chamber 2 that melts the incinerated ash at a high temperature to form molten slag and the discharge chamber 11 that discharges the molten slag along with the combustion exhaust gas generated at the time of melting. Slag guide means for allowing the slag guide means to naturally flow down to the discharge chamber 11, and the slag guide means has a V-shaped groove 18 formed by combining symmetric chromium alloy blocks 17, and this slag guide means A slag guide structure in a melting furnace comprising the left and right chromium alloy blocks 17 and a rod-like block 26 with a groove 26a for fitting the lower portions of both blocks 17 to prevent the blocks 17 from opening.    Another rod-shaped block 19 for mounting the slag guide means is provided on the upstream side of the grooved rod-shaped block 26 and fixed to the refractory material on the inner surface of the melting furnace. The slag guide structure in the melting furnace according to claim 1, wherein a groove is formed.    The slag guide structure in a melting furnace according to claim 1 or 2, wherein the chromium alloy of the slag guide means is an alloy material containing 50 wt% or more of chromium in the composition.    4. The base of the slag guide means and the upper surface of the V-shaped groove 18 at the end are made lower at the end than the base, and a groove liner 28 is mounted on the upper surface of the end. The slag guide structure in the melting furnace described in 1. The molten slag is melted from the melting chamber 2 by interposing between the melting chamber 2 that melts the incinerated ash at a high temperature to form molten slag and the discharge chamber 11 that discharges the molten slag along with the combustion exhaust gas generated at the time of melting. The slag guide means for allowing the slag to naturally flow down to the discharge chamber 11 is disposed, and the slag guide means has a V-shaped groove 18 formed by combining symmetric chromium alloy blocks 17 for easy replacement. In order to achieve this, a slag guide structure in a melting furnace in which the outer surface of the block is formed as a smooth curved smooth surface.

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