JP2005172381A - Method and device for supplying melted matter to melting furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of supplying a melted matter to a melting furnace, capable of preventing the burnout of a screw of a screw feeder and a trouble on sticking of the melted matter to a tip end part of a supply pipe of the screw feeder, by a simple method and means without using the large-scaled equipment and without needing the maintenance of the equipment caused by abrasion. <P>SOLUTION: In this method of supplying the melted matter A into the melting furnace 2 by a melted matter supply device 1 comprising the screw feeder 4 connected with a melted matter supply port of the melting furnace 2, the melted matter A is supplied in such a state that the vacancy rate in the screw feeder 4 from a furnace inner wall face 19 to a hopper 3 is 20 % or more. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a melting furnace for melting incineration residue, fly ash, etc. (hereinafter referred to as a material to be melted) that is discharged when municipal waste and industrial waste are incinerated in an incinerator. The present invention relates to a melt supply technology.

  Conventionally, incineration residue, fly ash, etc. (melted material) discharged when incineration of municipal waste and industrial waste in an incinerator is plasma-melted for the purpose of resource recycling, detoxification, and volume reduction. It is melted using a melting furnace such as a furnace and taken out as slag. In order to melt the melted material in the furnace body using the melting furnace in this way, the melted material discharged from the incinerator is subjected to pretreatment steps such as a screen, a magnetic separator, and a measuring instrument, and then melted. While being put into the hopper provided in the screw feeder connected to the furnace, it is supplied into the melting furnace from the screw feeder and melted.

  By the way, when the melted material is supplied to the melting furnace by the screw feeder as described above, the tip portion of the screw feeder facing the melting furnace is exposed to the high temperature atmosphere in the melting furnace. It is known that there is a problem that the melted material is melted and fixed before being supplied to the melting furnace, and the function of the screw feeder is impaired. As an improvement measure for this problem, for example, there is one proposed in Japanese Patent Laid-Open No. 2000-304226 (Patent Document 1).

  The above proposed method is a method of supplying a melt to a melting furnace in which the melt is supplied into the furnace by a melt supply apparatus having a screw feeder connected to a melt supply port of the melting furnace. In this case, when the melt is supplied into the furnace by the melt supply device, the tip of the outer cylinder of the screw feeder (referred to as a supply pipe in the present invention) is slid in the melt supply port. The material supply device is periodically moved back and forth with respect to the melting furnace, the melted material at the melt feed port is pushed into the furnace at the tip of the screw feeder, and the melt is fixed to the melt feed port It is something that breaks things down.

  In the proposed method, when the melt is supplied into the furnace by the melt supply apparatus, the melt supply apparatus is connected to the melting furnace while sliding the outer cylinder tip of the screw feeder in the melt supply port. The melted material at the melt feed port is extruded into the furnace at the tip of the screw feeder, and the melted material fixed to the melt feed port is broken down. Therefore, it is expected that the melt at the melt supply port can be easily removed, and that the melt is prevented from sticking to the melt feed port. In addition, even if the melt is fixed to the melt supply port, it is expected that the fixed melt can be removed without stopping the operation of the melting furnace.

However, in the proposed method, the above effect is expected. However, since the melt supply device such as a screw feeder and a hopper is moved back and forth with respect to the melting furnace, the drive device is necessary and the facility is large. In addition, since the tip of the outer cylinder of the screw feeder is slid within the melt supply port, its wear and maintenance are required, and there is a concern that the facility becomes complicated as a whole.
JP 2000-304226 A

  In view of the above circumstances, the present invention has been achieved by searching for means that can solve the above problems without causing the above-mentioned concerns, and the object thereof is not to use large-scale equipment. In addition, without the need for maintenance of equipment due to wear or the like, it is possible to prevent the burnout of the screw of the screw feeder and the trouble that the material to be melted adheres to the tip of the supply pipe of the screw feeder with simple methods and means. A method and an apparatus for supplying a material to be melted to a melting furnace are provided.

  In order to achieve the above object, a melt supply method to a melting furnace according to the present invention (Claim 1) is to supply a melt with a screw feeder connected to a melt supply port of the melting furnace. A method for supplying a melted material into a melting furnace by means of an apparatus, wherein the void ratio in the screw feeder between the wall surface of the furnace and the hopper (occupied by the gap in the cross section of the supply pipe of the screw feeder when the melt is supplied) A ratio) is set to 20% or more to supply a material to be melted.

  Generally, in a melting furnace, exhaust gas is sucked in order to prevent the exhaust gas generated during the melting process of the melted material from leaking to the outside, and the furnace pressure is slightly negative. Therefore, by using the melt supply method as described above, air or forced through the gap in the screw feeder between the furnace inner wall surface and the hopper from the hopper opening (melt input). A gas such as nitrogen blown into the hopper can be introduced into the hopper, and the introduced air can prevent the tip of the screw feeder from being heated more than necessary due to the furnace atmosphere, etc. It is possible to prevent the burning and the trouble that the material to be melted is melted and fixed in the supply pipe. And in order to acquire such an effect, it is desirable that the porosity is 20% or more. Further, the upper limit is not particularly limited, but is preferably about 80%. If the porosity becomes larger than this, there is a concern about a decrease in the atmospheric temperature in the furnace, and a decrease in the melt processing amount of the melted material in the melting furnace. Is concerned. Therefore, a desirable porosity is 20 to 80%. Further, in order to obtain the porosity as described above in the screw feeder between the furnace inner wall surface and the hopper, it is performed by controlling the amount of melt to be supplied from the pretreatment process to the hopper of the screw feeder, This can be achieved by operating the melting furnace without filling the hopper, for example, by controlling the supply speed of the screw feeder within the processing capacity range of the melting furnace.

  In the invention described in claim 1, the tip of the screw shaft of the screw feeder may be disposed so as to recede at least 20 mm or more from the inner wall surface of the melting furnace (invention 2). By comprising in this way, the heat which a screw shaft and the front-end | tip part of a blade | wing combine with ventilation | gas_flowing from the said space | gap part can reduce the heat received from the inside of a furnace, and a screw burnout and a to-be-melted material are more effective. Can be prevented from melting and adhering to the supply pipe. Further, the upper limit of the backward arrangement is not particularly limited, but is preferably about 200 mm, and if it is larger than this, there is a concern that the melted material accumulates in the supply pipe between the furnace inner wall surface and the tip of the screw shaft. In the case of deposition, there is a concern that the void ratio at the tip portion becomes insufficient and melted and fixed. Therefore, the preferable range of the backward arrangement is 20 to 200 mm.

  In the invention according to claim 1 or 2, the pitch of the screw blades of the screw feeder is formed to increase continuously or / and stepwise as it goes from the rear part to the tip, and gas is supplied. (Claim 3). By configuring in this way, the gap can be enlarged as it goes to the tip of the screw shaft of the screw feeder, and the melted material can be supplied into the furnace. The received heat can be reduced, and the trouble that the screw burnout and the melted material melt and adhere to the supply pipe can be prevented more effectively.

  In order to achieve the above object, a melt supply apparatus for a melting furnace according to the present invention (Claim 4) includes a screw feeder connected to a melt supply port of the melting furnace. In the apparatus for supplying the material to be melted into the melting furnace by the material supply apparatus, the tip of the screw shaft of the screw feeder is disposed so as to recede at least 20 mm or more from the furnace inner wall surface of the melting furnace, and the screw of the screw feeder The blade pitch is increased continuously or / and stepwise from the rear to the tip, and a gas supply hole is formed in the upper part of the supply pipe of the screw feeder. By configuring in this way, a gas such as air can be supplied from the gas supply hole into the supply pipe, and a gap can be formed in the supply pipe from the gas supply hole to the furnace inner wall surface. The heat received by the gas such as the supplied air from the inside of the furnace by the screw shaft and blade tips can be reduced, and the trouble of screw burning and melting of the melted material to the supply pipe can be prevented.

  As described above, according to the melt supply method to the melting furnace according to the present invention, the burning of the screw of the screw feeder can be performed without using large-scale equipment and without requiring equipment maintenance due to wear or the like. In addition, it is possible to prevent a problem that the material to be melted adheres to the tip of the supply pipe of the screw feeder.

  In addition, according to the melt supply device to the melting furnace according to the present invention, it is possible to prevent the burnout of the screw of the screw feeder and the trouble that the melt is stuck to the tip of the supply pipe of the screw feeder. Can be melted

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of an apparatus for supplying a melt to a melting furnace according to the present invention. In the figure, reference numeral 1 denotes a melt supply device, 2 denotes a melting furnace, and the melt supply device 1 is connected to a side wall portion of the melting furnace 2.

  The melt supply apparatus 1 includes a hopper 3 and a screw feeder 4 provided in communication with a lower portion of the hopper 3. The screw feeder 4 includes an outer cylinder serving as a supply pipe 5, a screw shaft 6 inside thereof, and screw blades 7 formed in a spiral shape on the outer peripheral surface of the screw shaft 6, and the screw shaft 6 is rotationally driven by a drive motor 8. It is comprised so that. The tip of the supply pipe 5 of the screw feeder 4 is airtightly attached and fixed to an opening 10 opened in the side wall 9 of the melting furnace 2. In this melt supply device 1, the melt A cut out from the supply device 11 in the previous process is received in the hopper 3, and the melt shaft A is rotated into the supply pipe 5 by the screw shaft 6 and the screw blade 7. Is fed to the melting furnace 2.

  The melting furnace 2 is an example of a plasma melting furnace, and the structure of the furnace itself generally includes a plasma torch 12 charged from the upper center of the plasma melting furnace 2 and a furnace installed on the furnace bottom side as shown in the figure. A plasma arc 15 that includes a bottom electrode 13, a DC power source 14 that supplies a DC voltage to the plasma torch 12 and the furnace bottom electrode 13, and serves as a heat source for melting the material A to be melted, As mentioned above, it is configured to flow to the molten slag bath 16 and the furnace bottom electrode 13 which is a cathode. The melt A supplied to the melting furnace 2 from the screw feeder 4 is heated to a melting temperature by a high-temperature plasma arc 15 irradiated from the plasma torch 12 to form molten slag, thereby forming a molten slag bath 16. At the same time, the molten slag overflows from the outlet 17 of the melting furnace 2 and is discharged outside the furnace. Reference numeral 18 denotes a tap cover, which exhausts exhaust gas and the like to a chimney or the like through a dust removal device (not shown).

  A method of supplying the melt A to the melting furnace 2 by the melt supply apparatus 1 having the above-described configuration is performed as follows. That is, the material A to be melted cut out from the supply device 11 in the previous process and received in the hopper 3 is conveyed and supplied to the melting furnace 2 in the supply pipe 5 by the rotating screw shaft 6 and the screw blade 7 of the screw feeder 4. However, at that time, the cutting amount of the melt A from the supply device 11 to the hopper 3 is controlled, and the transport amount of the melt A in the screw feeder 4 from the furnace inner wall surface 19 to the hopper 3 is As shown in FIG. 2, it supplies so that the space | gap part B from which the porosity becomes 20% or more in the cross section of the supply pipe | tube 5 is formed. The void ratio C is a ratio (C = B / D) of the void portion B to the cross-sectional area D obtained by removing the cross-sectional area of the screw shaft 6 from the cross-sectional area of the supply pipe 5.

  By supplying the melt A to the melting furnace 2 as described above, in the melting furnace 2, the exhaust gas generated in the melting process of the melt A is generally not leaked to the outside through the outlet cover 18. As the exhaust gas is sucked and the furnace pressure is slightly negative, as indicated by an arrow X from the opening of the hopper 3 through the gap B in the screw feeder 4 between the furnace inner wall surface 19 and the hopper 3. Air is introduced, and the introduced air can prevent the tip portion of the screw feeder 4 from being heated more than necessary by the furnace atmosphere or the like. A trouble that A is melted and fixed in the supply pipe 5 can be prevented.

  FIG. 3 is an enlarged vertical cross-sectional view of a main part of the melt supply apparatus applied to the melt supply method to the melting furnace according to the present invention. In FIG. 3, a melt supply device 20 is used instead of the melt supply device 1 shown in FIG. 1, and the melt supply device 20 is a screw blade 7 in the melt supply device 1. The pitch of the screw blades 21 is continuously increased from the rear to the tip (see FIG. 3a) and gradually increased (see FIG. 3b). ) Formed.

  In the melt supply device 20, when the melt A is supplied to the melting furnace 2, the gap B in the screw feeder 4 increases as it goes to the tip of the screw shaft 6. It becomes easy to introduce air from the void B, and is introduced in the same manner as or more than when the melt A is supplied to the melting furnace 2 by the melt supply apparatus 1 described above. It is possible to prevent the tip of the screw feeder 4 from being heated more than necessary by the atmosphere in the furnace due to air, and the screw shaft 6 and the screw blade 21 are burned out and the melted material A is melted and fixed in the supply pipe 5. Can prevent trouble.

  In order to obtain the above-mentioned effects more effectively, in FIG. 1 and FIG. 3, the distance L between the tip of the screw shaft 6 of the screw feeder 4 and the furnace inner wall surface 19 of the melting furnace 2 is at least 20 mm. It is preferable to dispose the above. By comprising in this way, the heat | fever which the front-end | tip part of the screw shaft 6 or the screw blade | wings 7 and 21 receives from the inside of a furnace combined with ventilation | gas_flowing from the space | gap part B can be reduced, and a screw shaft can be made more effective. 6 and screw blades 7 and 21 can be prevented from being burned out and troubles in which the material A is melted and fixed in the supply pipe 5 can be prevented.

  FIG. 4 is an enlarged vertical cross-sectional view of a main part of an apparatus for supplying a melt to a melting furnace according to another embodiment of the present invention. The melt supply device 22 shown in FIG. 4 is used in place of the melt supply device 1 shown in FIG.

  The melt supply device 22 includes a hopper 23 and a screw feeder 24 provided in communication with a lower portion of the hopper 23. The screw feeder 24 has the same configuration as the screw feeder 4 described above, and includes an outer cylinder serving as a supply pipe 25, a screw shaft 26 inside thereof, and a screw blade 27 formed in a spiral shape on the outer peripheral surface of the screw shaft 26. The screw shaft 26 is rotationally driven by the drive motor 28. The screw blades 27 are formed so that the pitch increases in three steps as the pitch goes from the rear part to the tip of the screw shaft 26. A gas supply hole 29 through which air or the like can be introduced is formed in the upper part of the supply pipe 25. The tip of the supply pipe 25 of the screw feeder 24 is airtightly attached and fixed to the opening 10 opened in the side wall 9 of the melting furnace 2, but the tip of the screw shaft 26 is melted during the fixing. A distance L (L = 20 mm or more) is opened from the furnace inner wall surface 19 of the furnace 2 so as to be retracted.

  According to the melt supply device 22 having the above-described configuration, the melt A cut out from the supply device 11 in the previous process and received in the hopper 23 is supplied by the rotating screw shaft 26 and the screw blade 27 of the screw feeder 24. 25 is conveyed and supplied to the melting furnace 2. Gas supply holes that are formed so that the pitch of the screw blades 27 increases in three stages as the screw shafts 26 move from the rear part to the tip of the screw shaft 26 and air or the like can be introduced into the upper part of the supply pipe 25 during the conveyance and supply. 29 is formed, the height of the melt A to be transported and fed decreases toward the melting furnace 2 in the supply pipe 25, and the upper part of the melt A and the top of the supply pipe 25 are increased. A gap B is formed between the peripheral surface and the air, and air is introduced into the melting furnace 2 through the gap B and the gas supply hole 29 from the opening of the hopper 23 (the inlet of the melt A). Thus, the introduced air can prevent the tip portion of the screw feeder 24 from being heated more than necessary due to the atmosphere in the furnace, etc., and the screw shaft 26 and the screw blades 27 are burned out, and the melted material A Supply pipe The trouble to melted and fixed can be prevented in the 5.

It is a schematic longitudinal cross-sectional view of the to-be-melted material supply apparatus to the melting furnace which concerns on this invention. It is a partial explanatory view of the screw feeder concerning the present invention, Comprising: a is an expanded longitudinal section, b is a YY sectional view of a. It is a principal part expanded longitudinal cross-sectional view of the to-be-melted material supply apparatus applied to the to-be-melted material supply method to the melting furnace which concerns on this invention, Comprising: When a is the pitch of screw blades becoming large continuously, b is a screw This is a case where the pitch of the blades increases stepwise. It is a principal part expansion longitudinal cross-sectional view of the to-be-melted material supply apparatus to the melting furnace of another embodiment which concerns on this invention.

Explanation of symbols

1: Melted material supply device 2: Melting furnace 3: Hopper 4: Screw feeder 5: Supply pipe 6: Screw shaft 7: Screw blade 8: Drive motor 9: Side wall 10: Opening portion 11: Supply device 12: Plasma torch 13 : Furnace bottom electrode 14: DC power supply device 15: Plasma arc 16: Molten slag bath 17: Outlet port 18: Outlet port cover 19: Furnace inner wall surface 20: Molten material supply device 21: Screw blade 22 Melted material supply Device 23: Hopper 24: Screw feeder 25: Supply pipe 26: Screw shaft 27: Screw blade 28: Drive motor 29: Gas supply hole A: Material to be melted B: Cavity part L: Tip of screw shaft and inside of furnace Distance between walls X: Arrow indicating air flow

Claims (4)

  A method of supplying a material to be melted into a melting furnace by means of a material to be melted supply device provided with a screw feeder connected to a material to be melted in a melting furnace, the inside of the screw feeder between the wall surface of the furnace and the hopper The molten material is supplied to the melting furnace, wherein the molten material is supplied at a porosity of 20% or more (ratio of the gap portion in the cross section of the supply pipe of the screw feeder when the molten material is supplied).   The method for supplying a material to be melted to the melting furnace according to claim 1, wherein the tip of the screw shaft of the screw feeder is disposed so as to be retracted by at least 20 mm from the inner wall surface of the melting furnace.   The pitch of the screw blades of the screw feeder is increased continuously or / and stepwise as it goes from the rear part to the tip, and gas is supplied to the melting furnace according to claim 1 or 2. Melt supply method. In an apparatus for supplying a material to be melted into a melting furnace by a material supply apparatus having a screw feeder connected to a material supply port of a melting furnace, the tip of the screw shaft of the screw feeder is a furnace of the melting furnace. The screw feeder is disposed so as to recede at least 20 mm from the inner wall surface, and the pitch of the screw blades of the screw feeder is continuously or / and gradually increased as it goes from the rear to the tip, and the screw feeder is supplied. An apparatus for supplying a material to be melted to a melting furnace, wherein a gas supply hole is formed in an upper portion of a pipe.