JP2004162970A - Recycling furnace and its heating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recycling furnace for efficiently recovering a carbide and a thermal decomposition gas regardless of a simple apparatus configuration. <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. The grate is composed by forming a number of openings, thus achieving the straightening operation of the combustion exhaust gas from the combustion chamber under pressurization conditions. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a recycling furnace that realizes an effective thermal decomposition process.
[0002]
[Prior art]
As a method for treating industrial waste, various methods for pyrolyzing a recovered plastic product to generate a pyrolysis gas and a carbide are known (for example, see Non-Patent Document 1, and 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]
[Non-patent document 1]
JPO homepage • List of patent map creation themes by technical field (94 themes) • Machinery 6 Incinerator technology • 1.3.3 Dry distillation gasification combustion technology • http: // www. jpo. go. jp / indexj. htm
[Patent Document 1]
JP 2001-182935 A [Patent Document 2]
JP-A-2001-241632
[Problems to be solved by the invention]
By the way, conventional incinerators have to be complicated and expensive because of the treatment of various plastic products that are collected as industrial waste, and the efficiency of recovery of carbides and pyrolysis gases is high. Was also not satisfactory.
[0006]
The present invention has been made in view of this problem, and it is an object of the present invention to provide a recycling furnace that can efficiently collect carbides and pyrolysis gas while having a simple device configuration.
[0007]
[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. The grate has a large number of openings formed therein, and realizes a rectifying action of the combustion exhaust gas from the combustion chamber under a pressurized condition. Here, the pressurized condition means a state where a differential pressure is generated between the combustion chamber and the reaction chamber.
[0008]
According to the first aspect of the present invention, radiant heat transfer is realized by the combustion flame generated in the combustion chamber, and convection heat transfer to the processing target is realized by the high-temperature combustion exhaust gas. In addition, the grate according to the first aspect of the invention has a large number of openings formed therein and realizes a rectifying action of the combustion exhaust gas under a pressurized condition. Therefore, a local high-temperature portion is generated in the combustion flame. However, even if the combustion exhaust gas does not flow only through a specific flow path of the reaction chamber, it is possible to prevent the occurrence of temperature unevenness.
[0009]
In the recycling furnace according to claim 2, the reaction chamber provided on the upper side and the combustion chamber provided on the lower side are vertically divided via a grate through which combustion exhaust gas passes. A combustion reaction is realized inside a tube member that forms a flow path covering the entire region, and operation is performed by ejecting combustion exhaust gas from the tube member.
[0010]
The tube member typically forms a flow path in a meandering or spiral shape. In any case, since the flow path covers at least almost the entire area of the combustion chamber in a plane, uniform radiant heat transfer from the tube surface is realized, and convective heat transfer is realized by the discharged combustion exhaust gas. Further, since a combustion reaction is realized inside the tube member, the pyrolysis gas from the molten polymer compound does not burn.
[0011]
The invention according to claim 5 is a combustion method for a recycle furnace in which a reaction chamber provided on an upper side and a combustion chamber provided on a lower side are vertically divided through a grate through which combustion exhaust gas passes. A tube member that forms a flow path covering substantially the entire area of the combustion chamber is arranged, a combustion reaction is realized inside the tube member, and combustion exhaust gas is ejected from the tube member. This invention also has the same effect as the above-mentioned second invention.
[0012]
In the invention according to each of the above-mentioned claims, it is preferable that a polymer compound is treated and a carbide and a pyrolysis gas are generated. Here, the polymer compound is typically a plastic material, preferably a plastic material containing no chlorine. It is preferable that this polymer compound contain a significant amount of any 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.
[0013]
The invention according to each of the above claims 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. It is also preferable to apply the present invention to the treatment of a macromolecular compound that has been separated almost exactly. In this case, the high molecular compounds should be separated into the same kind, but the commonality of the composition does not matter.
[0014]
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 pyrolysis gas generated in the recycling furnace 1, and an exhaust gas boiler for generating steam from the combustion exhaust gas discharged from the co-firing furnace 2. 3 and an economizer 4 for preheating the water supply to the exhaust gas boiler 3.
[0015]
In this embodiment, the recycling furnace 1 is formed in a substantially cylindrical shape, and is vertically divided via a disc-shaped grate 5. A combustion chamber 1a surrounded by a refractory material is formed below the grate 5, and a reaction chamber 1b for accommodating a plastic material as waste is formed above the grate 5. A large number of openings are formed substantially uniformly in the disk-shaped grate 5 to communicate the upper and lower parts of the recycling furnace 1.
[0016]
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 the first embodiment (see FIG. 2), a diffusion type gas burner is arranged in the introduction section 6, and a minimum necessary combustion air is supplied by the blower 8 and at the same time, via the control valve V1. Gas fuel (for example, city gas 13A) is supplied.
[0017]
On the other hand, the reaction chamber 1b has an upper opening / closing door 10 that is opened when the object to be treated is charged, an outlet 11 for the pyrolysis gas generated from the reaction chamber 1b, and metal components and carbides remaining on the grate 5. And a take-out part 12 for recovering the same.
[0018]
FIG. 2A is a schematic view of the combustion chamber 1a according to the first embodiment as viewed from the inspection door 7 toward the introduction unit 6. As shown in the figure, a discharge port 13 for gaseous fuel is disposed substantially at the center of the combustion chamber 1a. The bottom of the combustion chamber 1a has an inclined surface that is inclined downward toward the center and extends in the discharge direction of the gaseous fuel, and is formed in an inverted trapezoidal shape in a sectional view. Therefore, the plastic material P liquefied and dripping from the grate 5 is collected at the center of the bottom, and the radiant heat from the flame portion F is effectively transmitted.
[0019]
The gas fuel from the discharge port 13 is mixed with combustion air and burns, and effectively heats the plastic material in the reaction chamber 1b by radiant heat transfer and convective heat transfer. However, since only a minimum necessary amount of air is supplied to the combustion chamber 1a, hot air containing no oxygen is output to the reaction chamber 1b. As a result, the plastic material is thermally decomposed and pyrolysis gas such as hydrogen or methane is generated. Is generated.
[0020]
In the case of the combustion chamber 1a of the first embodiment, a large number of small-diameter openings are formed in the grate 5 and, correspondingly, the discharge pressure of the diffusion gas burner is set sufficiently high. For this reason, the hot air that is vigorously blown out from the many openings spreads uniformly throughout the reaction chamber 1b, and effectively promotes the thermal decomposition of the plastic material. In other words, in the case of the first 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.
[0021]
3 and 4 show a combustion chamber 1a of a second embodiment using a radiant tube burner. As shown in FIG. 3 (a), the illustrated radiant tube TU connects three curved pipes RA10 to RA12 and four straight pipes RA20 to RA23 in a meandering manner to cover the entire area of the combustion chamber 1a. The surface of the tube serves as a heat source to realize a thermal decomposition process. Then, the combustion gas generated by igniting the mixture of the gaseous fuel and air flows from the straight pipe RA20 on the proximal end side to the straight pipe RA23 on the distal end side.
[0022]
On the side surface of the straight pipe RA23 on the distal end side, two lengthwise opening grooves H1 and H2 are formed over substantially the entire length. As shown in FIG. 3B, the first opening groove H1 opens in the horizontal direction, and the second opening groove H2 opens diagonally downward. Therefore, the combustion gas introduced from the straight pipe RA20 finishes the combustion reaction in the course of flowing through the radiant tube TU, and the combustion exhaust gas passes through the open grooves H1 and H2 of the straight pipe RA23 and is directed substantially horizontally and obliquely downward. Will be squirted. The bottom of the combustion chamber 1a has a downwardly inclined surface extending toward the center and extending in a direction orthogonal to the straight pipes RA20, RA21, RA22, and RA23. Therefore, the plastic material P and the like that has liquefied and dripped from the grate 5 are collected at the center of the bottom, and the radiant heat from the radiant tube TU is effectively transmitted.
[0023]
The hot air (combustion exhaust gas) injected into the combustion chamber 1a is introduced from the combustion chamber 1a into the reaction chamber 1b. In the case of the second embodiment, the grate 5 has a large-diameter opening. Are introduced into the reaction chamber 1b with almost no pressure loss. In the second embodiment, since the radiant tube TU is arranged so as to spread over the entire area of the combustion chamber 1a, it is possible to realize substantially uniform radiant heat transfer. Further, as in the first embodiment, Since no flame is blown out to the combustion chamber 1a, a locally high-temperature portion is not generated and there is no risk of drift, so that the opening of the grate 5 can be set to a large diameter.
[0024]
When a radiant tube burner is used as in the second embodiment, the liquid plastic material P dripping from the reaction chamber 1b is vaporized after coming into contact with the radiant tube TU or dropping on the floor. However, since this pyrolysis gas is introduced into the co-firing furnace 2 without burning, it is also preferable in this respect. The temperature of the combustion chamber 1a in this embodiment is set to about 700 ° C.
[0025]
Hereinafter, a recycling apparatus EQU using the recycling furnace 1 according to the embodiment will be described. As shown in FIG. 1, the co-firing furnace 2 includes a diffusion-type gas burner 14 on one side of a combustion space. Although the configuration of the diffusion type gas burner 14 is not particularly limited, for example, as shown in FIG. 5, the pyrolysis gas of the recycle furnace 1 is introduced into the inner tube 15a of the double tube 15, while the outer tube 15b of the double tube is inserted into the outer tube 15b of the double tube. Has introduced gas fuel, the secondary fuel. These 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 to burn. Then, combustion air is supplied to a side surface of the enlarged diameter portion 16 by a blower 17.
[0026]
Since the recycling furnace 1 mainly functions as a carbonization furnace, the pyrolysis gas output from the recycling furnace 1 and the gas fuel supplied to the outer pipe 15b are burned in a mixed state. Specifically, the control valve V2 is controlled by the temperature sensor TE and the control unit CTL2 disposed at the output 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.
[0027]
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. 6 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.
[0028]
As shown in FIG. 6B, 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.
[0029]
Next, the operation of the recycling apparatus EQU utilizing the recycling furnace 1 according to the embodiment will be described. Here, a manufacturing plant for sheet materials and the like, which is used for snacks and the like and is made by laminating a plastic film on the upper and lower sides of an aluminum foil, and treats pieces of the sheet material discharged in a day in batches. explain.
[0030]
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 required minimum amount of combustion air is supplied by the blower 8. In this case, the temperature of the reaction chamber 1b is equal to or higher than the thermal decomposition temperature (300 to 400 ° C.) of the polymer compound (plastic) based on the preset combustion amount and the melting point (700 ° C).
[0031]
As described above, the hot air in the predetermined temperature range containing almost no oxygen flows through the reaction chamber 1b, whereby the plastic material is thermally decomposed to generate a pyrolysis gas such as hydrogen or methane. The pyrolysis 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 subjected to a thermal decomposition treatment, and an excessive carbon content remains as carbide. Also, the aluminum contained in the plastic film remains as an aluminum foil in a dry state without melting.
[0032]
Therefore, in a state where the recycling furnace 1 is cooled, aluminum can be collected and distributed as valuable resources. In addition, it is possible to distribute the carbides as valuables after they are collected as they are or after granulation. By the way, in the above description, for convenience, the recycling furnace has been described as functioning as an ideal carbonization furnace, but this does not prohibit the functioning of the recycling furnace as a carbonization furnace.
[0033]
【The invention's effect】
As described above, according to the present invention, it is possible to realize a recycling furnace that can efficiently collect carbides and pyrolysis gas while having a simple apparatus configuration.
[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 first embodiment.
FIG. 3 is a schematic plan view showing a combustion chamber of a second embodiment.
FIG. 4 is a schematic diagram illustrating a combustion chamber of a second embodiment.
FIG. 5 is a schematic diagram showing a configuration of a diffusion type gas burner.
FIG. 6 is a schematic diagram illustrating an example of an exhaust gas boiler.
[Explanation of symbols]
1a Combustion chamber 1b Reaction chamber 5 Grate TU tube member (radiant tube)

Claims (5)

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,
The recycle furnace, wherein the grate has a large number of openings formed therein, and realizes a rectifying action of combustion exhaust gas from the combustion chamber under a pressurized condition. 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 recycling chamber, a combustion reaction is realized in a tube member forming a flow path covering at least substantially the entire area of the combustion chamber, and the combustion chamber is operated by ejecting combustion exhaust gas from the tube member. 3. The recycling furnace according to claim 1, wherein a pyrolysis gas and a carbide are generated by treating a polymer compound as a processing target. 4. The recycling furnace according to any one of claims 1 to 3, wherein the polymer compound contains only a specific limited metal component. A reaction chamber provided on the upper side, and a combustion chamber provided on the lower side, a method of heating a recycling furnace partitioned vertically by a grate through which combustion exhaust gas passes,
Heating of a recycling furnace in which a tube member forming a flow path covering substantially the entire area of the combustion chamber is arranged, and a combustion reaction is realized inside the tube member, and combustion exhaust gas is ejected from the tube member. Method.

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