JP4667905B2 - Induction heating type distillation furnace - Google Patents

Description

    The present invention relates to a batch processing induction heating type carbonization furnace that performs carbonization processing by induction heating on waste containing polymer compounds such as paints and resins, particularly metal waste such as used beverage cans.

  The batch processing type induction heating type carbonization furnace is described in, for example, Patent Document 1 and Patent Document 2, and FIG. 4 shows a conventional configuration of this type of carbonization furnace again. In FIG. 4, a cylindrical dry distillation tank 2 made of a magnetic material (iron) is installed in a closed cylindrical furnace body 1 that forms an inert gas atmosphere, and a heating coil 3 is provided outside the furnace body 1. Has been placed. The heating coil 3 is excited by an excitation power source 4 and induction heats the dry distillation tank 2. The furnace body 1 made of a heat-resistant heat insulating material is provided with an upper lid 5 and a bottom lid 6, and a charging hopper 8 for charging a dry distillation object 7 into the dry distillation tank 2 is connected to the upper lid 5 via a shooter 9. A discharge tray 10 for receiving the dry matter 7 discharged from the dry distillation tank 2 is installed below the bottom. By replacing the inside of the furnace with an inert gas (nitrogen) introduced from an inert gas tank (not shown), oxygen is shut off, and the dry distillation gas generated in the furnace is discharged to an exhaust gas treatment facility (not shown). Yes.

  In order to operate the carbonization furnace of FIG. 4, the material 7 to be dried 7 is temporarily stored in the input hopper 8 by a conveyor (not shown), and the furnace body 1 and the input hopper 8 are replaced with an inert gas. When the oxygen concentration inside the furnace body 1 and the charging hopper 8 reaches a predetermined value, for example, 3% or less, the material 7 to be dried is charged from the charging hopper 8 into the carbonization tank 2, and the heating coil 3 is energized to dry the distillation tank. 2 is induction heated. The to-be-distilled material 7 thrown into the dry distillation tank 2 is supported by the furnace bottom 11 attached on the bottom cover 6. The to-be-distilled material 7 is heated by radiation from the carbonization tank 2 or heat conduction, and after reaching a predetermined temperature, it is kept at that temperature for a certain period of time to perform a dry distillation process. By heating the to-be-distilled material 7, a polymer compound (for example, paint for beverage cans) is thermally decomposed to generate a combustible dry distillation gas, which is sent to an exhaust gas treatment facility for processing.

The to-be-distilled material 7 after the carbonization treatment is opened to the discharge tray 10 by opening the bottom lid 6, cooled to a predetermined temperature, and then taken out and sent to the next step. On the other hand, the furnace body 1 closes the bottom lid 6 and replaces the inside with an inert gas for the next dry distillation treatment. When the inert gas replacement in the furnace main body 1 is completed, the to-be-distilled product 7 is stored in advance, and the to-be-distilled product 7 is put into the dry distillation tank 2 from the charging hopper 8 in which the inert gas is replaced, and the next dry distillation treatment is started To do.
Japanese Patent Laid-Open No. 10-43714 JP 2000-239209 A

The conventional carbonization furnace as described above has the following problems.
(1) Opening the bottom lid to discharge the dry matter after carbonization will cause outside air to enter the furnace and increase the oxygen concentration in the furnace. However, in the continuous treatment, the carbonization tank once finished with the carbonization process is at a high temperature, so if the product to be dried is again put into the furnace as it is, the temperature of the product to be distilled rises due to the heat from the carbonization tank. However, there is a risk that the contained polymer compound decomposes to cause combustion or explosion. Therefore, the inert gas replacement is performed until the oxygen concentration in the furnace is lowered to a predetermined value before charging the dry matter, but the efficiency of the continuous treatment is lowered due to the time required for this.
(2) Since the to-be-distilled product that has been subjected to the carbonization process is exposed to the outside air at a high temperature when it is taken out to the discharge tray outside the furnace, the to-be-distilled product such as a beverage can is oxidized by the metal, Recovery and purity are reduced. In addition, in the invention described in the cited reference 2, the to-be-distilled material (carbon material) after the carbonization treatment in the pyrolysis furnace is carried into a cooling unit having a closed and sealed structure and cooled. There is no change in that the to-be-dried product is exposed to the outside air at a high temperature when it is transported from.
(3) When cooling the dry matter discharged to the discharge tray, it takes a lot of time to lower the temperature of the dry matter. In the invention described in the cited document 2, the to-be-dried product is stored in a container and carried into a cooling unit, and the to-be-dried product in the container is sprayed with cooling water to cool the to-be-dried product. Since only the to-be-distilled material located in the upper part in a container is produced, the spray water which remains without vaporizing arises, and it is difficult to cool uniformly to the to-be-dried object in the lower part in a container.

  The present invention has been made to solve the above-mentioned problems, and prevents intrusion of outside air into the furnace when taking out the product to be dried out of the furnace, and eliminates the need for inert gas replacement in the furnace during continuous processing. As a result, the processing time required for one batch is shortened, oxidation of the carbonized material subjected to the carbonization treatment is prevented, the metal recovery rate and purity are improved, and the temperature of the discharged carbonized material is further shortened. It is an object to lower it evenly and uniformly.

In order to solve the above-described problems, the present invention provides a dry distillation tank for storing a dry distillation object in a furnace main body that forms an inert gas atmosphere, and the heating coil installed outside the furnace main body is used for the dry distillation tank. In the induction heating type carbonization furnace in which the carbonized product in the carbonization tank is subjected to carbonization treatment and the carbonized product after the carbonization treatment is discharged from the lower part of the furnace body, An airtightly connected discharge chamber connected to the lower portion of the furnace body and an airtight conveyor duct having a partition lid that is connected to the discharge chamber and that can be opened and closed at the other end are provided inside the furnace body. And a means for replacing the inside of the discharge chamber and the conveyor duct with an inert gas separately from the furnace body, and further, the inside of the discharge chamber and the conveyor duct is not disposed below the furnace body. Active moth An openable and closable bottom lid is provided for discharging the to-be-dried material from the furnace main body after the replacement to the discharge chamber, and the puddle discharged to the discharge chamber in the conveyor duct The conveyor which conveys the to-be-dried material processed is provided (Claim 1).

  According to the first aspect of the present invention, after the discharge chamber and the conveyor duct are in an inert gas atmosphere, the lower part of the furnace body is opened to discharge the dry matter, so that the outside air does not enter the furnace. In addition, since the to-be-dried product after the carbonization treatment is discharged into the discharge chamber of the inert gas atmosphere, it is not oxidized by touching the outside air, and the discharged to-be-dried product is further disposed in the conveyor duct of the inert gas atmosphere. Therefore, the material to be dried can be sent to the next process without contacting with the outside air.

  In the invention of claim 1, a discharge tray having a closed structure having a bottom lid that can be opened and closed may be connected to the other end of the conveyor duct (invention 2). The to-be-dried material conveyed in the conveyor duct by the conveyor is taken out by opening the partition lid. At that time, outside air enters the conveyor duct and the discharge chamber. Therefore, if a discharge tray having a sealed structure is connected to the conveyor duct and the material to be dried is discharged from the conveyor to the discharge tray, the amount of outside air entering the conveyor duct is reduced. The material to be dried from the discharge tray is taken out by closing the partition cover of the conveyor duct and then opening the bottom cover of the discharge tray. In addition, a means to replace the inside of the discharge tray with an inert gas is provided, and if the discharge tray is placed in an inert gas atmosphere before transferring dry matter from the conveyor to the discharge tray, the intrusion of outside air is more reliably blocked. be able to.

  According to the present invention, a closed discharge chamber and a conveyor duct are provided in the lower part of the furnace body, and the to-be-dried material is discharged from the furnace body by discharging the to-be-dried material after the dry distillation treatment to the discharge chamber replaced with the inert gas. When oxygen is discharged, the oxygen concentration in the furnace does not increase, and the dry matter to be subjected to the next treatment can be immediately introduced without replacing the inside of the furnace with an inert gas, so that the continuous treatment efficiency is improved.

  In addition, since the discharge chamber has a low oxygen concentration, there is no risk of burning to-be-dried products discharged at high temperatures, and in particular, there is no oxidation of to-be-dried products containing metals such as beverage cans, which are recovered in a later process. Metal recovery efficiency and quality are improved.

  FIG. 1 is a longitudinal sectional view of a dry distillation furnace showing an embodiment of the present invention, FIG. 2 (A) is an enlarged transverse sectional view of a main part of the conveyor duct in FIG. 1, and FIG. 2 (B) is a longitudinal sectional view. In addition, the same code | symbol shall be used for the part corresponding to a prior art example. 1 and 2, the main difference from the conventional configuration of FIG. 4 is that a discharge chamber 12 having a sealed structure is hermetically connected to the lower portion of the furnace body 1, and one end of a conveyor duct 13 having a sealed structure is connected to the discharge chamber 12. Is connected. A partition lid 14 that can be opened and closed in the direction of the arrow is provided horizontally at the other end of the conveyor duct 13, and a hermetic discharge tray 16 having a bottom lid 15 that can be opened and closed is airtightly connected. The discharge chamber 12 is configured by surrounding with a steel plate. Moreover, the conveyor duct 13 is comprised by the steel plate in the shape of a tunnel of a cross section square, as shown to FIG. 2 (A).

  A conveyor 17 is installed in the conveyor duct 13, one end of which is located directly below the furnace body 1, and the other end reaches above the discharge tray 16. In the case of illustration, an apron conveyor is used as the conveyor 17. As is well known, an apron conveyor has a steel apron attached continuously between two roller chains driven by a motor (not shown), and bends at the apron seam. The conveyor 17 is not limited to the apron conveyor, and various types of conveyors such as a steel belt conveyor and a wire mesh belt conveyor can be used as long as they can transport the high temperature dry matter 7 in one direction. A discharge hopper 18 is installed between the bottom lid 6 of the furnace body 1 and the conveyor 17. A spray nozzle 19 for spraying cooling water to the dry matter 7 on the conveyor 17 is installed in the upper part of the conveyor duct 13, and the ambient temperature in the conveyor duct 13 is measured in the vicinity of the conveying surface of the conveyor 17. A temperature sensor 20 is installed.

  On the other hand, in FIG. 1, an inert gas (nitrogen gas) is supplied from an inert gas tank 21 to the charging hopper 8, the furnace body 1, the discharge chamber 12, and the conveyor duct 13 through the open / close valves 22 to 24, respectively. The gas in the hopper 8, the furnace main body 1, the discharge chamber 12 and the conveyor duct 13 is discharged to the exhaust gas treatment facility 28 via the open / close valves 25 to 27. Although not shown, the furnace body 1, the charging hopper 8, and the discharge chamber 12 are each provided with an oxygen concentration meter for detecting the oxygen concentration inside. The other configuration is substantially the same as the conventional configuration of FIG.

  In FIG. 1, for example, a process of subjecting a used beverage can as a dry distillation process to a dry distillation process is as follows. When a predetermined amount of dry matter 7 is stored in the charging hopper 8 from a conveyor (not shown), the upper lid (not shown) is closed to make the charging hopper 8 sealed. Next, the open / close valve 22 is controlled to supply nitrogen gas from the nitrogen gas tank 21 into the charging hopper 8. During the supply of nitrogen, the oxygen concentration in the charging hopper 8 is controlled by an oxygen concentration meter. The oxygen concentration is, for example, 3% or less of the predetermined concentration (four times the oxygen concentration at the upper limit of combustion limit calculated based on the gas components in the furnace) Nitrogen substitution is performed until the value satisfies the dilution value. Further, the gas discharged from the charging hopper 8 (air and nitrogen in the charging hopper) is discharged to the exhaust gas processing facility 28 by controlling the open / close valve 25. At this time, the opening and closing valves 23 and 26 are also controlled in the furnace main body 1 to perform nitrogen substitution in the same manner.

  When the oxygen concentration in the furnace body 1 becomes 3% or less, the bottom lid (not shown) of the charging hopper 8 is opened, and the dry distillation object 7 is charged into the dry distillation tank 2. Next, the dry distillation tank 2 is induction-heated by the heating coil 3, and after the dry distillation object 7 reaches a predetermined temperature, for example, 550 ° C., the dry distillation treatment is performed by holding for a certain time. Until the dry distillation of dry matter 7 is completed, the partition lid 14 is closed and the open / close valve 24 is controlled to supply nitrogen gas to the discharge chamber 12 and the conveyor duct 13 so that the oxygen concentration becomes 3% or less. Nitrogen replacement is performed until. During the nitrogen supply, the oxygen concentration is controlled by an oximeter. The discharged gas (air and nitrogen in the discharge chamber 12 and the conveyor duct 13) is discharged to the exhaust gas treatment facility 28 by controlling the open / close valve 27.

The to-be-distilled material 7 which has completed the dry distillation is discharged to the discharge hopper 18 by opening the bottom lid 6 as shown by a broken line in FIG. The bottom cover 6 opens both sides with the hinge as a fulcrum. Since the discharge chamber 12 and the conveyor duct 13 are already replaced with nitrogen, even if the bottom cover 6 is opened, air does not enter the furnace body 1 and the oxygen concentration does not increase. Further, even if the high temperature distillate 7 is discharged, the metal is not oxidized in the discharge chamber 12. The discharged to-be-distilled material 7 is stored in the discharge hopper 18 and supported on the upper surface of the conveyor 17. Therefore, as shown in the figure, the partition lid 14 is opened and the conveyor 17 is activated. When the conveyor 17 starts moving in the direction of the arrow, the to-be-dried material 7 in the discharge hopper 18 is cut out from the bottom portion by a fixed amount, and is diffused and conveyed to the upper surface of the conveyor 17 as shown in FIG.

  As shown in FIG. 2, cooling water is sprayed from the spray nozzle 19 to the to-be-distilled material 7 on the conveyor 17, and it cools to about 100-200 degreeC. Since the to-be-dried product 7 on the conveyor 17 is diffusing, it is easily exposed to the sprayed water, and the sprayed water is completely evaporated to cool the to-be-dried product 7 in a short time by the heat of evaporation. Water vapor generated by vaporization of the spray water is discharged to the exhaust gas treatment facility 28 together with nitrogen gas. The to-be-dried material 7 after cooling falls to the discharge tray 16 from the end of the conveyor duct 13. The to-be-distilled matter 7 discharged | emitted to the discharge tray 16 opens the bottom cover 15 after closing the partition cover 14 of the conveyor duct 13, and conveys it to the following process with the conveyor which is not shown in air | atmosphere.

  The spray amount of the cooling water is controlled by the ambient temperature in the vicinity of the conveyor 17 measured by the temperature sensor 20. In that case, the flow rate of the cooling water may be changed with the speed of the conveyor 17 being constant, or the speed of the conveyor 17 may be changed with the flow rate of the cooling water being constant. Further, the cooling water can be sprayed intermittently, and the spraying interval or spraying time per time can be changed according to the ambient temperature. Furthermore, as shown in FIG. 3, spray nozzles 19 can be provided at a plurality of locations (two locations in the drawing) along the flow of the conveyor 17. As a result, when cooling water that cannot be vaporized by collecting water at once is collected on the conveyor, the water spray is divided into multiple times, and the required amount of cooling water can be sufficiently sprayed while avoiding water accumulation. it can.

  In the case of continuous processing, the charging hopper 8 retains the next batch during the dry distillation process and replaces with nitrogen, discharges the dry distillation object 7 subjected to the dry distillation process from the furnace body 1, and closes the bottom lid 6. The to-be-distilled material 7 of the next treatment is immediately put into the furnace from the charging hopper 8. Since there is no oxygen intrusion in the furnace, there is no danger of burning the dry distillation object 7 or explosion of the dry distillation gas even if the dry distillation object 7 is introduced at a high temperature. Therefore, it is not necessary to cool the inside of the furnace in order to input the dry matter 7 for the next treatment, and the time for the continuous treatment process is shortened. Thereafter, batch processing is continuously performed by repeating the above-described steps.

  The to-be-dried product 7 discharged from the conveyor 17 to the discharge tray 16 is taken out into the atmosphere by opening the bottom lid 15, and at that time, outside air enters the discharge tray 16. Therefore, in continuous processing, when the partition lid 14 is opened and the dry matter 7 is discharged to the discharge tray 16, oxygen in the discharge tray 16 may enter the discharge chamber 12 via the conveyor duct 13. Therefore, when there is such a concern, the partition lid 14 is closed and the inside of the discharge chamber 12 and the conveyor duct 13 is replaced with nitrogen before the dry matter 7 to be processed next is discharged from the furnace. This makes it possible to block oxygen more reliably. Alternatively, when the dry matter 7 is discharged from the discharge tray 16 to the atmosphere, the partition lid 14 and the bottom cover 15 are closed before the dry matter 7 to be processed next is discharged to the discharge tray 16. The discharge tray 16 can be replaced with nitrogen separately according to the path shown.

It is a longitudinal cross-sectional view of the dry distillation furnace which shows embodiment of this invention. It is a principal part enlarged view of the conveyor duct in the dry distillation furnace of FIG. 1, (A) is a cross-sectional view, (B) is a longitudinal cross-sectional view. It is a longitudinal cross-sectional view of the conveyor duct at the time of providing the spray nozzle of cooling water in two places. It is a longitudinal cross-sectional view of the dry distillation furnace which shows a prior art example.

DESCRIPTION OF SYMBOLS 1 Furnace body 2 Carbonization tank 3 Heating coil 4 Power supply 5 Top cover 6 Bottom cover 7 Dried object 8 Input hopper 12 Discharge chamber 13 Conveyor duct 14 Partition cover 15 Bottom cover 16 Discharge tray 17 Conveyor 18 Discharge hopper 19 Spray nozzle 20 Temperature sensor 21 Inert gas tank 28 Exhaust gas treatment equipment

Claims (2)

A dry distillation tank for storing a dry distillation object is installed in the furnace body forming an inert gas atmosphere, and by induction heating the dry distillation tank with a heating coil installed outside the furnace main body, In the induction heating type carbonization furnace for subjecting the carbonized product to carbonization, and discharging the carbonized product after the carbonization process from the lower part of the furnace body,
A discharge chamber connected to the sealed structure hermetically the bottom of the furnace body, and a conveyor duct of the closed structure having an openable and closable partition cover the other end connected to the discharge chamber is provided, the interior of the furnace body And a means for replacing the inside of the discharge chamber and the conveyor duct with an inert gas separately from the furnace main body, and further, the discharge chamber and the conveyor at a lower portion of the furnace main body. An openable and closable bottom lid is provided for discharging the to-be-dried material that has been subjected to dry distillation from the furnace body to the discharge chamber after the inside of the duct is replaced with an inert gas, and the discharge chamber is provided in the conveyor duct. An induction heating type carbonization furnace characterized in that a conveyor is provided for conveying the to- be-distilled material discharged to the bottom .   The induction heating type dry distillation furnace according to claim 1, wherein a discharge tray having a sealed structure having a bottom lid that can be opened and closed is connected to the other end of the conveyor duct.

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