JP2004162971A - Recycling furnace and its combustion method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recycling furnace for solving the problem of remaining deposits and for reducing operation time and saving fuel. <P>SOLUTION: A reaction chamber 1b being provided at the upper side and a combustion chamber 1a being provided at the lower side are divided into upper and lower portions via a grate 5 for passing a combustion exhaust gas. A burner for achieving combustion by air for combustion is arranged in the combustion chamber 1a, and an air nozzle NZ being extended in parallel with the jetting direction of combustion flame by the burner is arranged. The air for combustion is jetted out of a jet nozzle formed at the air nozzle NZ. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a recycling furnace that realizes an efficient dry distillation gasification treatment.
[0002]
[Prior art]
As a method of treating industrial waste, various methods of pyrolyzing a collected plastic product to produce a dry distillation gas and an ash are known (for example, see Patent Documents 1 and 2). Note that, in this specification, regardless of the description in other documents, pyrolysis of an object in a state where there is no excess oxygen is referred to as carbonization processing, and a furnace that realizes the carbonization processing is referred to as a carbonization furnace. In accordance with this usage, supplying a certain amount of excess oxygen to thermally decompose the object is called dry distillation, and a furnace for realizing the dry distillation is called a dry distillation furnace.
[0003]
Then, a pyrolysis gas is generated from the carbonization furnace, and a carbide is generated when the carbonization process is completed. On the other hand, a carbonization gas is generated from the carbonization furnace, and an ash is generated when the carbonization process is completed. Further, in this specification, the recycling furnace includes at least a carbonization furnace and a carbonization furnace, and the combustible gas includes at least a pyrolysis gas and a carbonization gas.
[0004]
[Patent Document 1]
JP 2001-182935 A [Patent Document 2]
JP-A-2001-241632
[Problems to be solved by the invention]
By the way, the conventional recycling furnace has a problem in the combustion method.For example, when a plastic material is treated, the molten material dripping on the floor surface solidifies after the operation of the recycling furnace is finished, or the floor surface is melted. When the air nozzle is arranged, the subsequent maintenance is difficult, such as clogging the air nozzle. This point is more conspicuous as the distance from the combustion flame increases, and the amount of the remaining deposits is solidified. Therefore, it has been difficult to remove the deposits in combination with the narrowness of the combustion chamber.
[0006]
In the first place, it is not necessary to collect all of plastic waste as combustible gas, but by burning part of it, we aim to shorten operating time and save fuel for burners installed in recycling furnaces. Is also suitable.
[0007]
The present invention is based on such an idea, and provides a recycling furnace capable of solving the problem of the remaining sediment, shortening the operation time and saving fuel of a burner installed in the recycling furnace. As an issue.
[0008]
[Means for Solving the Problems]
In order to solve the above problem, the recycling furnace according to claim 1 is configured such that a reaction chamber provided on an upper side and a combustion chamber provided on a lower side are vertically divided via a grate through which combustion exhaust gas passes. In the combustion chamber, an air nozzle extending in parallel with the direction in which the combustion flame is blown by the burner is arranged, and combustion air is blown out from a blowout port formed in the air nozzle.
[0009]
Further, in the combustion method for a recycling furnace according to claim 6, the amount of fuel supplied to the burner is adjusted so that the temperature of the combustion chamber is constant.
[0010]
In each of the above inventions, radiant heat transfer is realized by the combustion flame generated in the combustion chamber, and convection heat transfer to the object to be processed is realized by the high-temperature combustion exhaust gas. In addition, if the combustion air is blown out from the outlet formed in the air nozzle toward the combustion flame, it is possible to treat the falling objects on the floor surface, and after the operation, only incinerated matter (incinerated ash) remains. Absent. Here, it is typical that the combustion flame is ejected in the horizontal direction. In this case, the air nozzle extends in parallel with the ejection direction of the combustion flame, and is preferably slightly more than the horizontal direction. Sprays combustion air downward.
[0011]
The air nozzles are preferably respectively mounted on opposed wall surfaces of a combustion chamber orthogonal to a direction in which the combustion flame is ejected. It is further preferable that a shielding material is disposed on the upper portion of the air nozzle so that a falling object from the grate does not contact the air nozzle.
[0012]
In addition, if the floor of the combustion chamber is set lower at the center than at the periphery and has a groove extending in the direction in which the combustion flame is ejected, falling objects can be reliably burned from the grate. This groove is typically substantially U-shaped or inverted trapezoidal.
[0013]
In the present invention, typically, a high-molecular compound is treated, and a dry distillation gas and incinerated ash (incinerated ash) are generated. Here, the polymer compound is typically a plastic material, preferably a plastic material containing no chlorine. This polymer compound preferably contains some metal component. It is more preferable that only a specific limited metal component is contained, and it is most preferable that only one kind of metal component is contained.
[0014]
The present invention is suitably applied to the treatment of a specific polymer compound that is constantly discharged from the same facility such as a manufacturing factory or a processing factory, but is not limited to the one discharged from the same facility, and is almost accurately separated. It is suitable to be applied to the treatment of a polymer compound obtained. In this case, the high molecular compounds should be separated into the same kind, but the commonality of the composition does not matter.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described based on a recycling furnace 1 according to an example. FIG. 1 is a schematic diagram showing a recycling apparatus EQU using a recycling furnace 1. The recycling apparatus EQU includes a recycling furnace 1 functioning as a carbonization furnace, a co-firing furnace 2 for burning the carbonization gas generated in the recycle furnace 1, and an exhaust gas boiler 3 for generating steam from the combustion exhaust gas discharged from the co-firing furnace 2. And an economizer 4 for preheating the water supply to the exhaust gas boiler 3. Note that another heat exchanger (for example, a water heater) may be provided instead of the exhaust gas boiler 3.
[0016]
In this embodiment, the recycling furnace 1 is formed in a substantially cylindrical shape, and is vertically divided via a disc-shaped grate 5. At the lower part of the grate 5, there is provided a combustion chamber 1 a formed of a refractory material in a substantially rectangular shape, and at the upper part of the grate 5, there is provided a reaction chamber 1 b for accommodating a plastic material as waste. I have. A large number of openings are formed substantially uniformly in the disk-shaped grate 5 so that the upper and lower sides of the recycling furnace 1 communicate with each other.
[0017]
The combustion chamber 1a is formed at a height of about 80 cm from the viewpoint of maintainability. An introduction portion 6 for gas fuel and combustion air is provided on one side in the horizontal direction, and an inspection door 7 is provided on the other side. Is provided. In the case of this embodiment, a diffusion type gas burner is arranged in the introduction section 6, and combustion air is supplied by the blower 8, and gas fuel (for example, city gas 13A) can be adjusted via the control valve V1. Supplied to A part of the combustion air from the blower 8 is supplied to the air nozzle NZ.
[0018]
On the other hand, in the reaction chamber 1b, an upper opening / closing door 10 which is opened when the object to be treated (plastic material) is charged, an outlet 11 for combustible gas generated from the reaction chamber 1b, and incineration remaining on the grate 5 An extraction section 12 for collecting (incinerated ash) and metal components is provided.
[0019]
FIG. 2A is a schematic view of the combustion chamber 1 a of the embodiment, as viewed from the inspection door 7 toward the introduction unit 6. As shown in the figure, a gas fuel discharge port 13 is disposed substantially at the center of the combustion chamber 1a. On the side surface of the combustion chamber 1a, four air nozzles NZ extending in parallel with the discharge direction of the gas fuel and a shielding material CV that protects the molten material dripping from the grate 5 from touching the air nozzles NZ are provided. Are located. Since the height position of the air nozzle NZ is set higher than the maximum deposition height of the melt, there is no possibility that the air nozzle NZ is buried in the melt.
[0020]
As shown in FIG. 2A, the floor surface of the combustion chamber 1a is inclined with a downward slope toward the center, and is formed in an inverted trapezoidal shape in a sectional view. Therefore, the molten material dripping from the grate 5 is collected so as to approach the combustion flame ejected from the discharge port 13, and the radiation heat transfer is more effectively realized.
[0021]
As shown in FIG. 2B, each air nozzle NZ is formed with a large number of ejection ports, and ejects combustion air slightly downward from a horizontal direction toward a combustion flame. Therefore, the molten plastic material is burned by the combustion air ejected from the air nozzle NZ, and does not remain as a fixed substance.
[0022]
From the air nozzle NZ, an amount of air necessary to burn the melt deposited on the floor of the combustion chamber 1a is jetted, and a shielding member CV is disposed above the air nozzle NZ. Therefore, there is no possibility that the outlet of the air nozzle NZ is blocked by the molten material dripping from the grate 5.
[0023]
As described above, in the combustion chamber 1a of the embodiment, since the combustion air is ejected from the air nozzle NZ, the melt dripping on the floor of the combustion chamber 1a can be quickly processed. If such a configuration is not adopted, in particular, the melt generated at the end of the operation of the recycling furnace 1 will then adhere to the floor.
[0024]
As shown in FIG. 1, a temperature sensor TE1 is disposed above the combustion chamber 1a, and the control valve V1 adjusts the amount of gas fuel supplied so that the temperature thereof becomes a predetermined value. In this embodiment, the temperature of the combustion chamber 1a is controlled to about 600 ° C. to 700 ° C. by adjusting the supply rate of the gaseous fuel while keeping the supply rate of the combustion air constant. The specific temperature is determined according to the type of the plastic material.
[0025]
In any case, the supply amount of the gas fuel changes with time, but the supply of the gas fuel becomes maximum when the operation of the recycling furnace 1 is started. Thereafter, the supply of gaseous fuel is reduced according to the increase in the amount of carbonization gas generated. As described above, in the combustion chamber 1a of this embodiment, a part of the plastic material stored in the reaction chamber 1b functions as fuel by the combustion air ejected from the air nozzle NZ, so that the processing time can be shortened and The gas fuel used can be saved.
[0026]
A large number of small-diameter openings are formed almost uniformly in the grate 5 that partitions the combustion chamber 1a having the above-described configuration, and the discharge pressure of the diffusion-type gas burner is set to be sufficiently high. For this reason, the hot air that is vigorously ejected from the many openings spreads uniformly throughout the reaction chamber 1b, and effectively promotes the gasification of the plastic material by dry distillation. That is, in the case of this embodiment, although the pressure loss is generated by the small diameter of the opening of the grate 5, the rectifying action is exerted on the hot air introduced into the reaction chamber 1b. When the opening of the grate 5 is large, the pressure loss is reduced, but it is inappropriate because all the hot air may flow in a specific flow path formed by a local high-temperature portion of the flame.
[0027]
Hereinafter, a recycling apparatus EQU using the recycling furnace 1 according to the embodiment will be described for reference. As shown in FIG. 1, the co-firing furnace 2 includes a diffusion-type gas burner 14 on one side of a combustion space. The configuration of the diffusion type gas burner 14 is not particularly limited. For example, as shown in FIG. 3, while the dry distillation gas from the recycle furnace 1 is introduced into the inner tube 15a of the double tube 15, the outer tube 15b of the double tube is introduced into the outer tube 15b. Has introduced gas fuel. These two fuels are discharged toward the enlarged diameter portion 16 extending from the outer tube 15b, and are mixed with combustion air introduced from the side surface of the enlarged diameter portion 16 and burned. Note that combustion air is supplied to a side surface of the enlarged diameter portion 16 by a blower 17.
[0028]
As described above, since the recycling furnace 1 functions as a carbonization furnace, the carbonization gas generated in the recycling furnace 1 and the gas fuel supplied to the outer tube 15b are burned in a mixed state. . Specifically, the control valve V2 is controlled by the temperature sensor TE2 and the control unit CTL2 disposed at the discharge part of the co-firing furnace 2, and the temperature of the combustion exhaust gas is controlled to 800 ° C or higher. The volume of the co-firing furnace 2 and the supply amount of combustion air are set so that the residence time of the combustion gas (combustion flame and combustion completion gas) is 2 seconds or more.
[0029]
The exhaust gas boiler 3 is connected to the upper part of the co-firing furnace 2 and is integrally held. The configuration of the exhaust gas boiler 3 is not particularly limited, but in this embodiment, a once-through boiler as shown in FIG. 4 is used. This once-through boiler has a configuration in which a number of vertical water pipes 18... 18 are connected between an upper header 17A and a lower header 17B, and water is supplied to the lower header 17B while the vertical water pipe 18 is raised. Then, the mixture is brought into a gas-water mixed state, and sent to the steam-water separator 19 from the upper header 17A to be separated to obtain steam.
[0030]
As shown in FIG. 4B, the vertical water pipe 18 has a double structure of an inner water pipe group 18A and an outer water pipe group 18B arranged in an annular shape. Then, the combustion exhaust gas introduced from the exhaust gas outlet of the co-firing furnace 2 flows through the gap between the inner and outer water pipe groups 18A and 18B from the gas inlet 20 formed on one side of the inner water pipe group 18A, and the other of the outer water pipe group 18B. It is led out from a gas outlet 21 formed on the side. After the flue gas discharged from the gas outlet 21 undergoes further heat exchange in the economizer 4, the flue gas is led out to the chimney 23 by the induction fan 22 and released to the atmosphere.
[0031]
Next, the operation of the recycling apparatus EQU utilizing the recycling furnace 1 according to the embodiment will be described. Here, in a manufacturing plant for sheet materials etc., which are used for snacks, etc., which are made by laminating a plastic film on top and bottom of aluminum foil, where batches of scraps of sheet materials discharged daily are processed Will be described.
[0032]
In such a case, after the sheet material waste discharged the day before is charged into the reaction chamber 1b, the control valve V1 is opened and the combustion chamber 1a is opened with the doors 7, 10 and the take-out section 12 closed. The gas fuel is introduced into the fuel cell and the gas fuel is ignited while the combustion air is supplied by the blower 8.
[0033]
Then, the plastic material is carbonized to form a carbonized gas such as hydrogen or methane. The carbonization gas generated in the recycling furnace 1 is introduced into the co-firing furnace 2 and mixed with a separately introduced gaseous fuel and burned. As a result of such an operation, the plastic material in the reaction chamber 1b is dry-distilled, and only incinerated matter (incinerated ash) remains. Also, the aluminum contained in the plastic film remains as an aluminum foil in a dry state without melting.
[0034]
Therefore, in a state where the recycling furnace 1 is cooled, aluminum can be collected and distributed as valuable resources. Also, incinerated materials (incinerated ash) can be distributed as valuable materials such as cement raw materials. Further, since only the incinerated matter (incinerated ash) remains on the floor surface of the combustion chamber 1a, subsequent maintenance is easy. In the above description, for the sake of convenience, the recycling furnace 1 has been described as functioning as an ideal dry distillation furnace, but this does not prohibit the recycling furnace 1 from functioning as a carbonization furnace.
[0035]
【The invention's effect】
As described above, according to the present invention, it is possible to realize a recycling furnace that can solve the problem of the remaining deposits, shorten the operation time, and save fuel.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of a recycling apparatus using a recycling furnace according to an embodiment.
FIG. 2 is a schematic diagram illustrating a combustion chamber of the recycling furnace of FIG. 1;
FIG. 3 is a schematic diagram showing a configuration of a diffusion type gas burner.
FIG. 4 is a schematic view showing an example of an exhaust gas boiler.
[Explanation of symbols]
1a Combustion chamber 1b Reaction chamber 5 Grate NZ Air nozzle

Claims (6)

A reaction chamber provided on the upper side and a combustion chamber provided on the lower side are vertically divided via a grate through which combustion exhaust gas passes,
In the combustion chamber, an air nozzle that extends in parallel with the direction in which the combustion flame is ejected by the burner is arranged,
A recycling furnace wherein combustion air is ejected from an ejection port formed in the air nozzle. The recycling furnace according to claim 1, wherein the air nozzles are respectively attached to opposed wall surfaces of a combustion chamber orthogonal to a direction in which the combustion flame is ejected. 3. The recycling furnace according to claim 1, wherein a shielding material is disposed above the air nozzle, and a falling object from the grate is configured not to contact the air nozzle. 4. The recycling furnace according to any one of claims 1 to 3, wherein a center portion of the floor surface of the combustion chamber is set lower than a peripheral portion, and a groove extending in a direction in which the combustion flame is ejected is formed. The recycling furnace according to any one of claims 1 to 4, wherein a high-molecular compound is to be processed, and a dry distillation gas and an ash are generated. The combustion method for a recycling furnace according to any one of claims 1 to 5, wherein a fuel supply amount to the burner is adjusted so that a temperature of the combustion chamber is constant. Method.

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