JP3872418B2 - Recycling equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recycling apparatus that can effectively use energy and realize a stable and safe thermal decomposition treatment.
[0002]
[Prior art]
As a method for treating industrial waste, various methods are known in which a recovered plastic product is pyrolyzed to generate a combustible gas and a carbide (see, for example, Non-Patent Document 1, and Patent Documents 1 and 2).
[0003]
In this specification, regardless of the description in other documents, the thermal decomposition of an object in a state where there is no excess oxygen is referred to as carbonization treatment, and a furnace that realizes carbonization treatment is referred to as a carbonization furnace. Corresponding to this usage, supplying some excess oxygen to thermally decompose the object is called dry distillation treatment, and a furnace realizing the dry distillation treatment is called a dry distillation furnace.
[0004]
Then, pyrolysis gas is generated from the carbonization furnace, and carbide is generated when the carbonization process is completed. On the other hand, carbonization gas is generated from the carbonization furnace, and ash is generated when the carbonization process is completed. In this specification, the recycle 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.
[0005]
[Non-Patent Document 1]
Patent Office Homepage ・ Patent Map Creation Theme List by Technology Field (94 Themes) ・ Machine 6 Incinerator Technology ・ 1.3.3 Carbonization Combustion Technology ・ http://www.jpo.go.jp/indexj.htm
[Patent Document 1]
JP 2001-182935 [Patent Document 2]
JP 2001-241632 A
[Problems to be solved by the invention]
By the way, from the relationship of handling various miscellaneous plastic materials as waste, in some cases, more combustible gas than expected from the recycling furnace is generated, and it can not be completely burned in the mixed combustion furnace provided on the downstream side, In some cases, it was released into the atmosphere as unburned gas.
[0007]
In addition, since the amount of combustible gas generated is large, the combustion temperature has risen too much, which may exceed the heat resistance limit of the co-firing furnace. Here, it is conceivable to provide a sufficient margin for the combustion capacity and heat resistance characteristics of the mixed-burning furnace, but it is not appropriate to increase the size of the apparatus due to a situation that cannot normally occur. In particular, it is difficult to secure an installation space when a plastic material generated every day in a manufacturing factory or a processing factory is processed by a recycling apparatus installed in the same facility.
[0008]
The present invention has been made in view of the above-described problems, and has a simple apparatus configuration, and a recycling apparatus that does not cause a problem of generation of unburned gas regardless of the type and amount of the object to be processed. It is an issue to provide.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a recycling furnace that realizes carbonization or carbonization, and a combustible gas generated in the recycling furnace while supplying secondary fuel as necessary. In the recycle apparatus provided with the co-firing furnace to be burned, the adjusting means for adjusting the supply amount of the secondary fuel based on the outlet temperature of the co-firing furnace, and the outlet temperature of the co-firing furnace is the combustion capacity of the co-firing furnace. And safety means for reducing the amount of heating to the recycling furnace when the corresponding first reference value is exceeded.
[0010]
The combustion capacity of the co-fired furnace includes at least the ability to achieve complete combustion and the heat-resistant temperature. In the present invention, it is preferable to generate a combustible gas and a carbide (or an ash) by using a polymer compound as a treatment target. The polymer compound is typically a plastic material, preferably chlorine. It is a plastic material that does not contain any part. The present invention is preferably applied to the treatment of a specific polymer compound that is regularly discharged from the same facility such as a manufacturing plant or a processing plant, but is not limited to the one discharged from the same facility, and can be separated almost accurately. It is also suitable to apply to the treatment of the polymer compound prepared. In this case, the polymer compounds should be classified into the same kind, but the commonality of the composition is not questioned.
[0011]
The present invention, when the outlet temperature of the state that the safety means has functions exceeds the second reference value, that further comprise a cooling means for cooling said recycle reactor. Here, the cooling means is typically sprayed with water. In addition, when the recycle furnace functions as a carbonization furnace, the safety means preferably reduces the gas fuel and the combustion air correspondingly. On the other hand, when it functions as a dry distillation furnace, it is suitable to cope with it by reducing only the oxygen supply amount.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples. FIG. 1 is a schematic diagram illustrating a recycling apparatus EQU that realizes a combustion control method according to an embodiment. The recycle apparatus EQU generates steam from a recycle furnace 1 that functions as a carbonization furnace or a carbonization furnace, a co-fired furnace 2 that combusts combustible gas generated in the recycle furnace 1, and combustion exhaust gas discharged from the co-fired furnace 2. An exhaust gas boiler 3 and an economizer 4 that preheats water supplied to the exhaust gas boiler 3 are mainly provided. In addition, the mixed-fired furnace 2 realizes space saving by integrating the exhaust gas boiler 3 and the economizer 4 disposed on the upper part thereof.
[0013]
The recycling furnace 1 is formed in a substantially cylindrical shape in this embodiment, and is divided vertically by a disc-shaped grate 5. The lower part of the grate 5 is provided with a combustion chamber 1a formed of a refractory material in a substantially rectangular shape, and the upper part of the grate 5 is provided with a reaction chamber 1b for storing a plastic material to be processed. ing. The disk-shaped grate 5 is formed with a large number of openings substantially uniformly to allow the upper and lower sides of the recycling furnace 1 to communicate with each other.
[0014]
The combustion chamber 1a is formed with a height of about 80 cm from the viewpoint of maintainability, and 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 disposed in the introduction section 6, and combustion air is supplied by the blower 8 and gas fuel (for example, city gas 13 </ b> A) is supplied.
[0015]
In this embodiment, gas fuel and combustion air are supplied to the diffusion gas burner via the damper device DUP1 and the control valve V3. The damper device DUP1 and the control valve V3 can adjust the opening degree, but are normally maintained at a predetermined opening degree. And only when the combustion exhaust gas temperature of the mixed combustion furnace 2 exceeds the first reference temperature T1, based on the temperature sensor TE disposed at the exhaust gas outlet of the mixed combustion furnace 2, gas fuel and combustion air to the recycling furnace 1 The flow rate is adjusted to suppress the thermal decomposition of the plastic material.
[0016]
The reaction chamber 1b provided at the upper part of the grate 5 has an upper opening / closing door 10 that is opened when a plastic material to be treated is introduced, a lead-out portion 11 for combustible gas generated from the reaction chamber 1b, and a grate 5 and an extraction part 12 for recovering carbides and metal components remaining on the substrate 5. Further, a spray nozzle NZ is arranged in the reaction chamber 1b, and when the control valve V1 is opened, cooling water is sprayed into the reaction chamber 1b.
[0017]
The control valve V1 is opened and closed based on a temperature sensor TE disposed at the exhaust gas outlet of the co-firing furnace 2, and a large amount of combustible gas exceeding the schedule is generated from the reaction chamber 1b to When the temperature of the exhaust gas outlet exceeds the second reference temperature, the thermal decomposition of the plastic material is suppressed by spraying the cooling water.
[0018]
FIG. 2A is a schematic view of the direction from the inspection door 7 toward the introduction portion 6. As shown in the figure, a gas fuel discharge port 13 is disposed substantially at the center of the combustion chamber 1a. In addition, the bottom surface of the combustion chamber 1a has an inclined surface that is inclined downward toward the center and extends in the gas fuel discharge direction, and is formed in an inverted trapezoidal shape in a sectional view. Therefore, the plastic material P liquefied and dropped from the grate 5 is collected at the center of the bottom, and the radiant heat from the flame part F is effectively transmitted.
[0019]
A large number of small-diameter openings are formed in the grate 5, and the discharge pressure of the diffusion gas burner is set sufficiently high correspondingly. Therefore, the hot air blown out from a large number of openings spreads uniformly throughout the reaction chamber 1b and effectively promotes the thermal decomposition of the plastic material. That is, in the case of this embodiment, the pressure loss is caused by the small diameter of the opening of the grate 5, but it exerts a rectifying action on the hot air introduced into the reaction chamber 1b. In addition, when the opening of the grate 5 is large, the pressure loss is reduced, but all the hot air may flow in a specific flow path formed by a local high temperature portion of the flame and the like, which is not suitable.
[0020]
As shown in FIG. 1, the co-firing furnace 2 includes a diffusion gas burner 14 on one side of the combustion space. The configuration of the diffusion gas burner 14 is not particularly limited. For example, as shown in FIG. 3, the combustible gas from the recycling furnace 1 is introduced into the inner pipe 15a of the double pipe 15, while the outer pipe 15b of the double pipe is introduced. Introduces gas fuel as secondary fuel. Both of these fuels are discharged toward the enlarged diameter portion 16 extending in the outer tube 15b, mixed with combustion air introduced from the side surface of the enlarged diameter portion 16, and burned. Note that combustion air is supplied to the side surface of the enlarged diameter portion 16 by a blower 17.
[0021]
When the recycle furnace 1 functions as a carbonization furnace, the pyrolysis gas generated in the recycle 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 based on the detection of the temperature sensor TE disposed at the exhaust gas outlet of the co-fired furnace 2, and the temperature of the combustion exhaust gas is managed at about 800 ° C to 900 ° C. Further, the volume of the co-firing furnace 2, the supply amount of combustion air, and the like are set so that the residence time of the combustion gas (combustion flame and combustion completion gas) is 2 seconds or more.
[0022]
The exhaust gas boiler 3 is connected to the upper part of the mixed-burning 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. 5 is used. This once-through boiler has a structure in which a number of vertical water pipes 18... 18 are connected between an upper header 17A and a lower header 17B, while supplying water to the lower header 17B and ascending the vertical water pipe 18. The air-water mixed state is supplied to the air-water separator 19 from the upper header 17A and separated to obtain steam.
[0023]
As shown in FIG. 5B, 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. 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 tube groups 18A and 18B from the gas inlet 20 formed on one side of the inner water tube group 18A, and the other of the outer water tube group 18B. Derived from a gas outlet 21 formed on the side. The combustion exhaust gas derived from the gas outlet 21 is further subjected to heat exchange by the economizer 4, and then is guided to the chimney 23 by the induction fan 22 and released to the atmosphere.
[0024]
Next, the operation of the recycling apparatus EQ configured as described above will be described. Here, a typical operation scheduled and an operation in the case where the combustion temperature becomes higher than the planned temperature depending on the type and amount of the plastic material input will be described.
[0025]
[Typical typical actions]
Normally, a predetermined amount of gas fuel and a minimum amount of combustion air are fixedly supplied to the diffusion gas burner of the recycle furnace 1, and the reaction chamber 1b has a predetermined temperature not containing oxygen. Hot air in the region (300 to 400 ° C or higher) circulates. As a result, the plastic material is pyrolyzed to generate pyrolysis gas such as hydrogen and methane. The plastic material P that has been liquefied and dropped into the combustion chamber 1a is effectively thermally decomposed at the bottom surface.
[0026]
The pyrolysis gas generated in the recycle furnace 1 is introduced into the co-firing furnace 2 and mixed with the gas fuel, which is a secondary fuel introduced separately, and burned. As described above, the amount of gas fuel introduced into the co-firing furnace 2 is controlled based on the outlet temperature of the co-firing furnace 2, and specifically, the outlet temperature is maintained at about 800 ° C to 900 ° C. As such, gas fuel is supplied.
[0027]
FIG. 4 illustrates the temporal transition of the amount of gas fuel supplied from the start of operation of the recycle furnace 1, and immediately after the start of operation, a large amount of gas fuel is consumed because there is little generation of pyrolysis gas. Thereafter, it is shown that the supply of gas fuel decreases as the amount of pyrolysis gas generated increases.
[0028]
By the way, it is desirable that the recycling apparatus EQU is operated so that the amount of steam output from the exhaust gas boiler 3 is constant. Then, since a certain amount of heat is required in the exhaust gas boiler 3, in the co-firing furnace 2, the sum of the heat generated by the pyrolysis gas generated in the recycle furnace 1 and the heat generated by the gas fuel of the secondary fuel is constant. It is controlled to become.
[0029]
As shown in the figure, the amount of pyrolysis gas produced decreases after reaching the peak value, and accordingly, when the amount of gas fuel supplied increases again and the amount of pyrolysis gas produced becomes zero, The supply amount reaches the maximum value. Then, after the predetermined amount of time has elapsed since the supply amount of the gas fuel reaches the maximum value, the operations of the recycle furnace 1 and the co-firing furnace 2 are all stopped. As a result of such an operation, the plastic material in the reaction chamber 1b is completely pyrolyzed, and excess carbon remains as carbide in the reaction chamber 1b.
[0030]
[Operation when the temperature of the co-firing furnace 2 rises above the setting]
By the way, depending on the type and amount of the plastic material put into the recycling furnace 1, a thermal decomposition gas more than planned may be generated, and the temperature may further rise even if the gas fuel to the mixed combustion furnace 2 is shut off. Hereinafter, description will be made based on FIG.
[0031]
During normal operation, the amount of gas fuel supplied to the co-firing furnace 2 is adjusted by the control of the control unit CTL2, and the combustion exhaust gas temperature is managed at about 800 ° C to 900 ° C as described above. However, even if the gas fuel is finally shut off, the amount of pyrolysis gas generated is large, so the combustion exhaust gas temperature may exceed the first reference temperature (= T1) (point A in FIG. 6).
[0032]
In such a case, the supply of gas fuel to the recycling furnace 1 is decreased by the control of the control unit CTL1. Specifically, by restricting the opening degree of the damper device DUP1 and the control valve V3, the combustion temperature of the combustion chamber 1a of the recycling furnace 1 is lowered to suppress the thermal decomposition of the plastic material. As a result, the generation of pyrolysis gas is suppressed, and the combustion exhaust gas temperature of the co-firing furnace 2 eventually falls below the first reference temperature (= T1). Then, after that, the opening degree of the damper device DUP1 and the control valve V3 is fixed to the initial state, and the amount of gas fuel supplied to the co-firing furnace 2 is adjusted to maintain the combustion exhaust gas temperature in a predetermined temperature range.
[0033]
However, as an exception, even if the opening degree of the damper device DUP1 and the control valve V3 is reduced to the limit, the combustion exhaust gas temperature of the co-firing furnace 2 may further increase (see B in FIG. 6). Therefore, in such a case, on the condition that the second reference temperature (= T2) is exceeded, the control valve V1 is opened and the cooling water is sprayed from the spray nozzle NZ toward the reaction chamber 1b. As a result of this operation, the thermal decomposition of the plastic material is forcibly blocked and the generation of pyrolytic gas is suppressed.
[0034]
If the combustion exhaust gas temperature of the co-firing furnace 2 drops and falls below the second reference temperature T2, the spraying of the cooling water is stopped, and if it falls below the first reference temperature T1, it returns to normal control. is there.
[0035]
As described above, in the recycling apparatus according to the embodiment, the double safety means is provided, so that the mixed combustion furnace and the exhaust gas boiler are not damaged and the unburned gas is not released into the atmosphere. The first reference temperature is set to about 950 ° C., for example, and the second reference temperature is set to about 1000 ° C., for example.
[0036]
In the above description, for the sake of convenience, the recycle furnace has been described as functioning as an ideal carbonization furnace, but it does not prohibit the recycle furnace from functioning as a dry distillation furnace.
[0037]
【The invention's effect】
As described above, according to the present invention, it is possible to realize a recycling apparatus that has a simple apparatus configuration but does not cause a problem of generation of unburned gas regardless of the type and amount of the object to be processed.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating the overall configuration of a recycling apparatus 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 view showing a configuration of a diffusion gas burner.
FIG. 4 is a diagram for explaining a combustion operation in a mixed furnace.
FIG. 5 is a schematic view showing an example of an exhaust gas boiler.
FIG. 6 is a diagram illustrating a combustion control method according to an embodiment.
[Explanation of symbols]
1 Recycling furnace 2 Mixed-burning furnace EQU Recycling equipment CTL2 Adjustment means (control unit)
TE monitoring means (temperature sensor)
CTL1 Safety means (control unit)
T1 First reference value T2 Second reference value

Claims (3)

In a recycling apparatus provided with a recycle furnace that realizes carbonization treatment or dry distillation treatment, and a co-firing furnace that burns combustible gas generated in the recycle furnace while supplying secondary fuel as necessary,
Adjusting means for adjusting the supply amount of the secondary fuel based on the outlet temperature of the co-fired furnace;
The outlet temperature of the mixed combustion furnace, when exceeding the first reference value which is determined in correspondence with the combustion capability of the co-firing furnace, Bei example a safety means for reducing the amount of heat to the recycle reactor,
The recycling apparatus further comprising cooling means for cooling the recycling furnace when the outlet temperature at the time of functioning of the safety means exceeds a second reference value . The recycling apparatus according to claim 1 , wherein the safety means correspondingly reduces gas fuel and combustion air to the recycling furnace. The recycling apparatus according to claim 1 , wherein the cooling unit is realized by a water cooling operation by spraying water.

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