JP2006036886A - Thermal decomposition treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently dehalogenate waste plastics including a halogen-based plastics by a simple apparatus. <P>SOLUTION: The preheated pulverized halogen-based plastics stored in a container 2 are inserted to the interior of an applicator 23. Microwaves are fed through holes formed in the right and left, and back side faces of the applicator 23 from a magnetron 26. A pipe 30 for collecting hydrogen halide is fitted in the hole at the ceiling part of the applicator, and the hydrogen halide generated by heating the halogen-based plastics is introduced to an unshown neutralizing treatment device to make the hydrogen halide harmless by converting the hydrogen halide into a neutralized salt. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal decomposition treatment system, and more particularly to a system for safely separating halogen from plastic waste materials containing organic halogen compounds (halogen-based plastics) such as vinyl chloride without causing environmental impact. It is suitable for disposal processing.

  In recycling or disposal of organic halogen compounds such as vinyl chloride (hereinafter referred to as “halogen-based plastics”) and plastic waste materials containing them, it is extremely important to separate the halogens economically and safely in advance. This is because when such plastic waste is simply burned, extremely harmful and dangerous chemical substances such as dioxins and dibenzofuran are generated in the process. Hereinafter, the situation of this point will be described by taking vinyl chloride as an example, but it goes without saying that the object of treatment of the present invention is not limited to vinyl chloride.

Vinyl chloride is divided into hard vinyl chloride used for piping and building materials, and soft vinyl chloride used for agriculture, electric wire coating, flooring, etc., but each is a plastic that is widely used for industrial consumer use. . The domestic production of vinyl chloride is 2148k tons (2003 results), accounting for 16.1% of the total domestic plastic production. The world's total vinyl chloride production is 26M tons (2000 statistical data). Patent Documents 1 to 3 can be cited as disclosures of related technologies in this field.
JP 2000-286240 A JP 2001-250672 A JP 2002-217640 A

  Although this vinyl chloride has a high utility value, it causes environmental pollution at the disposal stage, so that its use is being restricted despite its high convenience. This is because chlorine (halogen group atoms) and additives such as plasticizers and stabilizers contained in vinyl chloride are known to cause environmental pollution. Nevertheless, it is because of the excellent properties of vinyl chloride that it is currently produced and used in large numbers.

  When disposing of vinyl chloride, it is known that toxic substances such as dioxins and dibenzofuran are generated by the incineration method, and even in the case of landfill, some of the additives are eluted in the leached water and become environmental hormone substances. It has been. About 50% of the currently used vinyl chloride is reused as recycled vinyl chloride, but the rest is being landfilled, so studies on safe disposal methods are being promoted. As one of them, a thermal decomposition method has been proposed.

  When the temperature of vinyl chloride is raised to 200 ° C., chlorine begins to separate from vinyl chloride in the form of hydrogen chloride (HCl). At higher temperatures, the separation rate of chlorine increases. When the temperature exceeds 350 ° C., the molecular structure from which chlorine is eliminated, that is, the skeletal structure (C—C bond) comes to be broken.

  By maintaining the temperature at which hydrogen chloride is separated and produced and proceeding with dechlorination, a skeletal structure from which chlorine is eliminated is obtained. Although this skeletal structure can be recycled as a building material, the conventional thermal decomposition method has not established a technique for efficiently extracting only the skeleton structure.

  FIG. 1A and FIG. 1B are process flowcharts illustrating a conventional halogen plastic processing method for processing waste halogen plastic without using microwaves. FIG. 1A is an explanatory diagram when used as a substitute for coke in a reducing agent such as iron ore. Since this method is not dehalogenated, it is assumed that it is used as a fuel or a blast furnace reducing agent at a high temperature so as not to generate dangerous substances such as dangerous dioxins. In this state, the furnace is severely corroded due to the effect of the separated halogen, so that it has not been put into practical use. This method cannot be recycled. This is because in order to use it as such a fuel / blast furnace reducing agent, it is essential to remove the halogen in advance. As an actual processing method, it was realistic to either clean thoroughly and reuse as recycled halogen-based plastic, or landfill.

  FIG. 1B is a flow chart of processing estimated from a conventional waste plastic dechlorination processing system, which is estimated from the explanation of the waste plastic dechlorination processing system on the homepage of JSW Japan Steel Works. On the JSW website, if the heating temperature is set at 390 ° C to separate halogen from general waste plastic (vinyl chloride content is 1-12% by weight), about 2 after the plastic reaches 390 ° C. Although it becomes 0.9 weight% in a minute, it has shown that it does not become 0.55 weight% or less even if it heats for 5 minutes or more.

  According to the method of JSW, it is shown that the residual chlorine concentration is lowered to 0.22% by weight by heating at 350 ° C. for 10 minutes. That is, when a plastic other than the halogen-based plastic has a softening point (or melting point) lower than that of the halogen-based plastic, if the surface of the halogen-based plastic is covered with this, the dehalogenation rate may decrease.

  In short, it is effective to raise the temperature in order to complete dehalogenation quickly. However, if this is done, the structure of the halogen-based plastic breaks down around the carbon-carbon bond, resulting in a skeletal structure. Use value as a body is lost. Further, other melted plastics cover the surface of the halogen-based plastics and hinder the separation of the halogens, which has been an inhibiting factor for the dehalogenation reaction and the generation of generated halogens.

  In order to improve this, when the decomposition temperature is lowered, for example, at 390 ° C., it stops at 0.55% by weight after 5 minutes, and further improvement cannot be achieved, but at 350 ° C., after 10 minutes, Although it becomes 0.22 weight% and there exists an effect which reduces a content rate, the heating for a long time is needed for that. In a conventional heating method, that is, a method other than microwave heating, the heat transfer is directed from the surface toward the center.

  FIG. 2 shows the result of measuring the temperature with respect to the elapsed time by putting a plastic of 5 cm cube in a circulating hot air type thermostatic chamber set at 100 ° C. In FIG. 2, the horizontal axis represents time, the vertical axis represents temperature, the straight line a represents the temperature of the thermostatic bath, the curve b represents the temperature change in a portion 5 mm from the plastic surface, and the curve c represents the temperature change in a portion 25 mm from the plastic surface. It is. As shown in Fig. 2, it took 67 minutes for the central part to reach 95 ° C, and it took 54 minutes for 95 ° C to reach even 5mm from the surface. It was.

 From this, it is easily estimated that if the temperature of the hot air is increased so as to shorten the dehydrochlorination treatment time, the surface will become carbonized at a temperature at which the chlorine in the central portion can be separated. .

  On the other hand, the upper limit of the temperature of the hot air is inevitably determined according to the purpose of recycling. In order to widen the scope of recycling and perform dechlorination in a short time using only the conventional heating method, hot air set at a temperature that does not cause carbonization must be used, and vinyl chloride must be crushed to fine particles. Therefore, since the process in the previous stage of the dechlorination process becomes long, the range of practical use is exceeded.

  For this reason, in the present recycling technology, a technology for producing recycled vinyl chloride by mixing waste of vinyl chloride alone with new vinyl chloride has been established. However, this is limited to the case where a large amount of vinyl chloride of the same component is disposed of, such as agricultural vinyl chloride. The reality is that most vinyl chloride waste materials cannot be recycled as recycled vinyl chloride because they contain a mixture of different additives.

  Therefore, for example, in order to use it as a reducing agent for iron ore, for example, there are many examples in which plastic waste material that has been dechlorinated as a pretreatment is placed in a blast furnace and disposed at a high temperature as a reducing agent for iron ore. The purpose of pre-treatment and dechlorination is that if this is not done, the inside of the furnace will be severely corroded by the influence of chlorine radicals generated in the high-temperature furnace. And since these recyclings are paid, most of the waste materials are disposed of in landfills or left unfilled.

  Therefore, a technical method for separating halogen from halogen-based plastics is required economically and safely as a pretreatment for recycling in order to eliminate such landfill disposal and field piles. If the halogen-based plastic can be dehalogenated in a low temperature range, it can be recycled not only as a reducing agent for fuel and blast furnaces but also as a building material because the skeleton structure of the halogen-based plastic remains as it is.

  An object of the present invention is to provide a thermal decomposition treatment system for efficiently dehalogenating halogen-based plastics, particularly waste plastics containing vinyl chloride, with a simple apparatus.

  In the present invention, by combining or switching the microwave heating means for heating from the inside of the halogen-based plastic and the heating means other than the microwave heating for heating from the surface, thermal decomposition in the lowest possible temperature region can be performed. It was carried out at high speed, and it was possible to obtain a skeletal structure efficiently.

  In particular, the present invention makes it possible to perform a low-temperature decomposition treatment by applying microwaves, and to separate the hydrogen halide from the halogen-based plastic, that is, to separate the halogen structure and the hydrogen from the halogen-based plastic in pairs. The remaining structure is left as it is, so that it can be recycled as building materials. In the following data, it is an experiment with a vinyl chloride polymer unless otherwise specified.

  This will be described by taking vinyl chloride as an example of a general halogen-based plastic. FIG. 3 is a diagram for explaining the molecular structure of vinyl chloride and the skeleton structure after dechlorination. The molecular structure of vinyl chloride has a structure in which a number of blocks are linked in a chain as shown in FIG. As a result of the experiment, this vinyl chloride is heated to raise the temperature, and when it reaches 220 ° C. or higher, thermal decomposition starts and hydrogen chloride is separated (described later). When the temperature exceeds 220 ° C, the thermal vibration energy of the chlorine atom becomes larger than the bond energy with the carbon atom and the chlorine atom is separated. This monoatomic state of the chlorine atom is a very active radical, It is presumed that the hydrogen atoms are taken away and separated in the form of hydrogen chloride as shown in FIG.

  It was confirmed that a unique phenomenon appears when such vinyl chloride is irradiated with microwaves. For commonly used plastics, PET, acrylic, polycarbonate, and vinyl chloride, the temperature dependence of the imaginary term (loss factor) of their complex dielectric constant was investigated in the range of room temperature to 150 ° C. This is the result of measuring the complex permittivity by irradiating a weak microwave when the plastic is left in a constant temperature bath at a constant temperature and the plastic reaches a constant temperature.

  FIG. 4 is a diagram for explaining the temperature change of the complex dielectric constant (imaginary term) of vinyl chloride. The horizontal axis represents the test temperature, and the vertical axis represents the complex dielectric constant (imaginary term). Although no significant temperature characteristic difference was observed for the real term of the complex permittivity, the loss coefficient related to the imaginary term, that is, the microwave heat generation, is the temperature of three types of plastics excluding vinyl chloride as shown in FIG. While the change was constant or a gradual linear change (increase), vinyl chloride had a loss factor equivalent to that of other plastics at about 75 ° C or less and an equivalent temperature gradient, but was about 75 ° C. Above, the temperature gradient increases rapidly.

  It is estimated that the temperature gradient of the loss factor has increased as a result of the phase transition from the change in color in synchronization with the change in temperature gradient. In the experimental temperature range, there was no change in color or abrupt change in loss factor for the other plastics. This is analyzed below.

The microwave absorption power P of the substance is
P = K ₁ fE ² ε ”
K ₁ : constant f: frequency E: electric field strength ε ″: complex dielectric constant ε = ε ′ + jε ″ imaginary term The calorific value Q of the substance is
Q = K ₂ fE ² ε ″
K ₂ : Constant f: Frequency E: Electric field strength ε ″: Complex permittivity ε = ε ′ + jε ″ can be expressed by an imaginary term.

Further, the penetration depth of microwave (power half depth) L is
L = K ₃ / (f · (ε _r ) ^1/2 ・ Tanδ)
K ₃ : constant f: frequency ε _r : relative permittivity (= ε ′ / ε ₀ )
tanδ: Dielectric loss angle of material (= ε ″ / ε ′)
It can be expressed as

  The power half depth of vinyl chloride is about 30 cm at room temperature. It remains about 30 cm up to 70 ° C. and about 10 cm at 150 ° C. The fact that this becomes shallow means that the amount of absorption of microwaves is the same at 30 cm at room temperature and 10 cm at 150 ° C.

  From the results shown in FIG. 4, the same microwave power is irradiated above the temperature that exceeds the temperature point (hereinafter referred to as phase transition point) where the temperature gradient of the imaginary term (loss factor) of the complex permittivity of vinyl chloride increases. Even so, it can be easily estimated that the rate of temperature rise of the vinyl chloride greatly increases because the calorific value is much larger than when microwaves are irradiated below the phase transition point.

  From this, when vinyl chloride is heated by using a conventional heating method, ie, heating using a heating means other than microwave heating, and microwave heating means, the heat transfer by the conventional heating method proceeds from the surface to the inside. On the other hand, when microwaves are irradiated, the entire system including the inside of vinyl chloride generates heat. Compared with the conventional heating method alone, the temperature rise rate of vinyl chloride is greatly increased, and once the temperature exceeds the phase transition point. When vinyl chloride is formed, it can be easily estimated that the internal heating by the microwave rapidly proceeds and the temperature rapidly rises.

  FIG. 5 is a diagram for explaining the relationship between the microwave irradiation time and the temperature of vinyl chloride. Here, the relationship between the irradiation time and the temperature of vinyl chloride when a microwave of about 600 W is irradiated to about 2 g of vinyl chloride is shown. The horizontal axis is the microwave irradiation time, the vertical axis is the vinyl chloride temperature, the curve a is preheated at 120.4 ° C., the curve b is preheated at 103.1 ° C., and the curve c is 82.3 ° C. The preheated curve d represents room temperature (no preheating). In addition, the temperature of the sample just before irradiating a microwave is taken as a parameter of the graph of FIG.

  When preheating was not performed, that is, when microwave irradiation was performed from room temperature, the temperature of the sample gradually increased, and when the temperature reached about 75 ° C. after about 30 seconds, it reached a peak temperature in about 100 seconds. In the sample preheated from 80 ° C. to 120 ° C., the sample temperature rapidly increases in 10 seconds or less and reaches a peak temperature of 250 ° C. to 350 ° C. in 100 seconds or less. Then, after reaching the peak temperature, the temperature decreases despite the microwave irradiation.

  FIG. 6 is a diagram for explaining the relationship between the microwave irradiation time and the temperature rise speed of vinyl chloride. FIG. 6 shows the results of obtaining the temperature change speed of the sample with respect to the microwave irradiation time under the same conditions as in FIG. 5. Curve a is preheated at 120.4 ° C., and curve b is preliminarily set at 103.1 ° C. Heated, curve c is preheated at 82.3 ° C., curve d is room temperature (no preheating). The temperature of the sample vinyl chloride rises by absorbing microwaves, and it can be estimated that the speed of rise is related to the remaining amount of chlorine atoms. The fact that the temperature of the sample has decreased despite being irradiated with the microwave means that the amount of heat generated by the microwave is smaller than the amount of heat that escapes from the sample.

  This is presumed to be one evidence that the chlorine atoms are sufficiently separated from the vinyl chloride. That is, the temperature reaches 230 ° C. to 350 ° C. in which chlorine atoms are separated from vinyl chloride by microwave irradiation in a short time, and a large amount of chlorine atoms are separated from vinyl chloride in a short time, so that the thermal decomposition of vinyl chloride is rapid. As a result of the completion of the separation of chlorine molecules, the amount of heat generated by the microwave is less than the amount of heat released. Precisely, the temperature of the sample is determined by the difference between the calorific value of the sample and the amount of heat that escapes from the sample, so even if the sample temperature peaks, it can not be said that the separation of chlorine atoms is completely completed. Think of it as an indication that the disassembly is complete. Although not shown in FIGS. 5 and 6, when the preheating temperature was set to 200 ° C. and microwave irradiation was performed, the temperature of vinyl chloride reached a peak in 5 seconds.

  FIG. 7 is an explanatory diagram of thermal decomposition by a conventional heating method, using a thermostatic bath using an electric heater, keeping vinyl chloride at a constant temperature, heating time and residual thermal decomposition (from the amount of separated hydrogen chloride) The relationship between the calculated amount of chlorine and the theoretical total amount of chlorine contained in vinyl chloride) is shown. The horizontal axis represents the heating time in the thermostatic chamber, and the vertical axis represents the remaining amount of chlorine. Curve a represents a set temperature of 220 ° C. Curve b represents a set temperature of 230 ° C. Curve c represents a set temperature of 240 ° C. Curve d represents a set temperature of 250 ° C. Curve e represents a set temperature of 270 ° C. .

  FIG. 7 shows the thermal decomposition speed when vinyl chloride is heated using a conventional heating method, that is, a heating method other than microwave heating. If it exceeds 220 ° C, thermal decomposition proceeds. Comparing the data heated from room temperature by microwave heating in FIG. 5 (maximum temperature is 270 ° C.) and the 270 ° C. standing data in FIG. 7, it can be said that the thermal decomposition is completed in 1/60 or less in microwave heating.

  As described above, if the conventional heating method and the microwave heating are used in combination, and simultaneous heating or switching heating is performed, chlorine atoms can be separated in a shorter time and at a lower temperature than when heating is performed only by the conventional heating method.

  Hereinafter, the process of the pyrolysis system using microwaves in the process of developing the process of the pyrolysis system according to the present invention will be described with reference to the flowcharts of FIGS.

  FIG. 8 is a flow chart of a basic process for microwave heating of a mixture of crushed halogen-based plastics or non-halogen-based plastics (other plastics), which is shown as thermal decomposition (1) using microwaves. In this case, the time during which the halogen-based plastic becomes higher than the phase transition start temperature is heated only by the microwave.

  The halogen-based plastic or the mixture with other plastics is pulverized or crushed and microwaved. The hydrogen halide separated by microwave heating is neutralized. The skeletal structure is put into a blast furnace, carbonized to plastic carbide, or reused as a building material. This heat treatment has a high energy cost because the heating efficiency of the heating time until it exceeds the phase transition point (about 75 ° C. for vinyl chloride) is low.

  FIG. 9 shows microwave heating after heating a mixture of crushed halogen-based plastics or non-halogen-based plastics (other plastics) using heating means other than microwave heating (conventional heating such as hot air, heater, and waste heat). It is a flowchart of a process. This is shown as thermal decomposition (2) using microwaves. In this method, the crushed halogen-based plastic is heated by the conventional heating method at the same time as microwave heating. In this case, it is possible to expand recycling and save energy costs by limiting the set temperature by conventional heating.

  FIG. 10 is a flowchart for explaining a method of heating a mixture of crushed halogen-based plastics or non-halogen-based plastics (other plastics) by a conventional heating method and then switching to microwave heating. This is shown as thermal decomposition (3) using microwaves. In this case, first, it is a method of heating by a conventional heating method (heating means such as hot air, a heater, and waste heat). That is, this is a method of separating hydrogen halide by irradiating microwaves after preliminarily heating the crushed halogen-based plastic above the phase transition temperature using, for example, waste heat of low energy. Since the microwave heating time can be shortened, the energy cost is reduced.

  FIG. 11 is a flowchart illustrating a method of adding microwave heating after preheating a mixture of crushed halogen-based plastics or non-halogen-based plastics (other plastics) above the phase transition temperature by a conventional heating method. is there. This is shown as thermal decomposition (4) using microwaves. In this method, a mixture of crushed halogen-based plastic or non-halogen-based plastic is preheated to a temperature higher than the phase transition temperature by a conventional heating method, and then microwave heating is added. In this case, since the microwave heating time can be minimized, the energy cost is the lowest.

  From the above experimental results and considerations, it is possible to leave the skeleton structure of the halogen-based plastic as it is if the halogen-based plastic is thermally decomposed by at least microwave irradiation to separate the halogen, so that it can be recycled as a building material. . Furthermore, the skeleton structure of halogen-based plastics treated in this way does not contain halogens that form dangerous halogen-based compounds that are generated when burned. Therefore, reducing agents such as iron in blast furnaces are used as cogeneration fuel. There is no need to worry about corrosion even when used as.

  And, by applying microwaves, the processing is completed in about 1/100 of the time of the thermal decomposition processing by the conventional heating method, so that it is possible to provide a halogen-based plastic decomposition processing system with high energy efficiency. .

  According to the present invention, a halogen-based plastic has a loss coefficient that is an imaginary term of a complex dielectric constant larger than that of other plastics even at room temperature, and when the temperature becomes higher than several tens of degrees Celsius, the temperature change of the loss coefficient rapidly increases. Since it becomes large, it can be shortened to about 1/100 compared with the thermal decomposition time by the conventional heating method by using at least microwave heating.

  In addition, as described with reference to FIG. 4, even at room temperature, heating can be performed by irradiating microwaves as in other plastics. That is, when the halogen-based plastic is heated by irradiation with microwaves and reaches 75 ° C. or more, such as vinyl chloride, the temperature gradient of the loss coefficient suddenly increases, the amount of heat generation increases, and the temperature rises rapidly (see FIG. 5 and FIG. 6). The cause of this is presumed to be the result of phase transformation occurring above this temperature, and the influence of microwaves of the halogen element bonded to the carbon atom appearing greatly. As a result, the temperature rapidly increases, the bond with the carbon atom is removed, and the halogen element can be separated (dehalogenated), so that it is considered that the decomposition has progressed rapidly.

  That is, according to the present invention, the set temperature for heating the halogen-based plastic by a heating means (conventional heating method) other than microwave heating, such as use of a heater, hot air, or other waste heat, is set to the halogen-based plastic. If microwave heating is performed at a temperature above the temperature point where the temperature gradient of the imaginary term (loss factor) of the complex permittivity increases (75 ° C or more in the case of vinyl chloride), the microwave heating alone is more effective. Furthermore, the halogen-based plastic can be thermally decomposed in a short time.

  If the temperature set by the conventional heating method is too high, the temperature of the halogen-based plastic that rises as a result of the rapid decomposition reaction by microwave heating is higher than the temperature at which the skeleton structure of the halogen-based plastic is decomposed and carbonized. Will also halve the utility value of recycling.

  For this reason, the heating temperature set by the conventional heating method is the temperature at which the halogen-based plastic starts to undergo a thermal decomposition reaction at the lower limit of the temperature point at which the temperature gradient of the imaginary term (loss factor) of the complex dielectric constant of the halogen-based plastic increases. (210 ° C. in the case of vinyl chloride) was set as the upper limit. However, for the purpose of simply putting the waste plastic into the blast furnace and reducing iron, for example, there is no problem in recycling even if the decomposition is slightly advanced and partially carbonized.

  In addition, only the conventional heating method is used for heating from the beginning. In a system where microwave heating is performed in the middle and simultaneous heating is performed, the timing of starting microwave irradiation is the temperature of the entire or at least a part of the halogen-based plastic (internal A sensor that detects the temperature (surface or surface temperature) is attached, and the sensor is at a temperature above the temperature point at which the temperature gradient of the imaginary term (loss coefficient) of the complex dielectric constant of the halogen-based plastic increases, and heat The microwave irradiation can be set to start within a temperature range below the temperature at which the decomposition reaction occurs. According to this system, the time to use expensive microwave energy can be shortened, so that energy costs can be saved.

  Similarly, it is roughly the same as starting the microwave irradiation after heating the halogen-based plastic to a temperature higher than the temperature at which the loss factor temperature gradient becomes large and below the temperature causing the thermal decomposition reaction by the conventional heating method. At the same time, the method of stopping heating by the conventional heating method is a system that combines the conventional heating method and microwave heating as a batch process, and can be applied to a method of automatically supplying halogen-based plastics or the like to the microwave irradiation chamber.

  That is, just below the hopper, a roller for crushing halogen-based plastics and a spiral conveyor with teeth are combined, and the plastic part crushed by the spiral conveyor is being sent to the microwave irradiation chamber by the conventional heating method. It is also possible to heat up to a required temperature (above the temperature at which the temperature gradient of the loss coefficient becomes large and below the temperature at which the thermal decomposition reaction occurs).

  The present invention is not limited to halogen-based plastics, and mixtures with other non-halogen-based plastics (for example, plastics such as PET) can also be thermally decomposed. For this purpose, the temperature set by the sensor is set to the lower limit of the temperature point at which the temperature gradient of the imaginary term (loss factor) of the complex permittivity of the halogen-based plastic increases, and the upper limit is set to the thermal decomposition start temperature or mixture of the halogen-based plastic. After setting and heating to the lower temperature range of the lowest softening temperature point among the non-halogen plastics contained, microwave irradiation can be started and thermal decomposition can be performed. This is to prevent the softened plastic from obstructing the halogen emission by covering the halogen-based plastic.

  In addition, the present invention obtains the timing at which the thermal decomposition is completed from the temperature change, so that the timing at which the microwave irradiation is stopped can be set starting from the time when the temperature time change becomes zero or minus, Energy costs can be saved.

  As described above, according to the present invention, since the halogen element can be separated from the halogen-based plastic in a short time, the processing capability is remarkably improved as compared with the conventional heating method. Further, since the halogen-based plastic skeleton structure is a method in which hydrogen halide is thermally decomposed at a low temperature that does not thermally decompose, the utility value as a building material is also produced.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings of the embodiments. In addition, the halogen-type plastic in each Example shall also contain the mixture which mixed the non-halogen-type plastic.

[Preparation stage]
Example 1 is a batch-type microwave application dehalogenation apparatus for processing halogen-based plastics in batches, that is, an apparatus for realizing the heat treatment system of the present invention. In the description of the examples, it is also referred to as a dehalogenation apparatus. In the first embodiment, a container for storing crushed plastic obtained by pulverizing a halogen-based plastic (also referred to as crushed waste plastic or simply waste plastic) is prepared.

  FIG. 12 is a cross-sectional view illustrating a container for a batch-type microwave application dehalogenation apparatus containing crushed plastic. In FIG. 12, reference numeral 1 denotes one of crushed halogen-based plastics (or a mixture of halogen-based plastics and non-halogen-based plastics) (crushed plastics). About the magnitude | size of crushing, what is necessary is just the maximum length of 2 times or less of the penetration depth (power half depth) of a microwave. In the case of vinyl chloride, even if it is 150 degreeC, since the electric power half depth is 10 cm, it should just be below this magnitude | size. Usually, there is no problem at all because the maximum length is about 1 cm.

  Reference numeral 2 denotes a container used when the crushed plastic 1 is put and irradiated with microwaves. The material is made of ceramics such as ceramics that can sufficiently withstand 350 ° C. or heat-resistant glass such as quartz. Of course, since a metal turntable is also employed in the turntable type microwave oven, a metal container may be used.

  In the case of a turntable type batch-type microwave application dehalogenation device, if the crushed plastic is of a stirring type, the container should have a circular cross section such as a bowl or a bath bowl. However, even if it is a turntable method, if it is not stirred, or in the case of a batch type microwave dehalogenation device other than the turntable method, the shape of the container is not limited.

  In the case of a batch-type microwave application dehalogenation apparatus such as an oven microwave oven that uses both microwave heating and conventional heating such as heater heating, a shallow container with a large area such as a bowl. Is good. This is because a larger surface area is easier to heat. Further, the crushed plastic 1 may be in either a preheated state using a heater or waste heat or a preheated state.

[Preheating]
The preheating will be described with reference to FIGS. Here, the structure of an apparatus that preheats crushed plastic containing at least a halogen-based plastic using a heater is shown. FIG. 13: is sectional drawing explaining the structural example of the preheating apparatus of a crushing halogen-type plastic. The description of each symbol is shown in the figure (the same applies to the following drawings). In FIG. 13, the crushed plastic 4 containing at least the halogen-based plastic charged into the hopper 5 moves from left to right in FIG. 13 according to the movement of the spiral conveyor 9 rotated by the motor 8, falls from the exit, and Enter 2.

  While the crushed plastic 4 is carried on the spiral conveyor 9, it is heated by the heater 7 that covers the spiral conveyor 9 from the outside. Here, the heat insulating cover 6 has a function of covering the heater 7 from the outside and preventing heat from escaping. Reference numeral 12 denotes an introduction line for supplying electricity to the heater.

  Here, the hollow cylindrical portion 15 moves the crushing plastic 4 from the left to the right by the action of the spiral conveyor 9. At this time, the temperature of the inner surface of the hollow cylindrical portion 15 corresponding to the portion covered with the heater 7 is The temperature above the temperature point at which the temperature gradient of the imaginary term (loss factor) of the complex dielectric constant of the halogen-based plastic increases, for example, 75 ° C or higher in the case of vinyl chloride, and the halogen-based plastic undergoes a thermal decomposition reaction. Sensors are used to control the temperature so that the temperature is less than the temperature at which hydrogen halide starts to be released, for example, in the case of vinyl chloride, the temperature is 210 ° C. or less.

  In practice, setting the temperature immediately before the temperature at which the thermal decomposition reaction occurs to start releasing the hydrogen halide may shorten the heating time. The crushing plastic 4 is heated while moving from left to right in the spiral conveyor 9 set to such a temperature. The heating temperature of the crushed plastic is determined by controlling the moving speed at this time.

  At this time, by optimizing the diameter of the narrowed portion 13 of the connection portion of the hopper 5 with the spiral conveyor 9, the amount of the crushed plastic 4 in the spiral conveyor 9 is slightly less than full so as to have fluidity. You can also do so. Then, if the right side of the spiral conveyor 9 is tilted upward, and the crushed plastic 4 moves up in the spiral conveyor 9 and simultaneously climbs up in the upper right direction, the heating easily proceeds.

  The above explanation is for the case where the crushing waste plastic is only a halogen-based plastic, but in the case of the plastic waste mixed with other plastics, it is matched with the plastic with the lowest softening point (melting point). It goes without saying that the upper limit of the temperature must be determined.

  FIG. 14 is a cross-sectional view of the shaking shown in FIG. 13 for explaining the device for preheating the crushed plastic 4 using a heating fluid using waste heat instead of the heater in the preheating device shown in FIG. . In this preheating device, the temperature of the heating fluid using waste heat is higher than the temperature point at which the temperature gradient of the imaginary term (loss factor) of the complex dielectric constant of the halogen-based plastic becomes large. For example, in the case of vinyl chloride Use a sensor to control the temperature so that it is 75 ° C or higher and below the temperature at which halogen-based plastics start to undergo hydrogenolysis and start releasing hydrogen halide. For example, in the case of vinyl chloride, the temperature is 210 ° C or lower. is doing. Actually, setting the temperature just before the temperature at which the pyrolysis reaction starts to start releasing hydrogen halide may shorten the heating time.

  Using the heating fluid set to such a temperature, the crushing plastic 4 is heated in the spiral conveyor while moving in the spiral conveyor 9 from the left to the right in FIG. The heating temperature of the crushed plastic 4 is determined by controlling the moving speed at this time. At this time, by optimizing the diameter of the narrowed portion 13 of the connection portion of the hopper 5 with the spiral conveyor 9, the amount of the crushed plastic 4 in the spiral conveyor 9 is slightly less than full so as to have fluidity. You can also do so. Similarly to the description with reference to FIG. 13, if the spiral conveyor 9 is tilted so that the crushed plastic moves up in the spiral conveyor at the same time, the heating easily proceeds.

  15 is a cross-sectional view similar to FIG. 14 for explaining another configuration example of the preheating device using waste heat shown in FIG. In FIG. 15, when hot air is used as the heating fluid, the hot air outlet side pipe that has finished heating the hollow cylindrical portion 15 of the spiral conveyor 9 is indicated by reference numeral 20 in FIG. If it is connected to the part close to the inlet side (left end), the temperature above the temperature point at which the temperature gradient of the imaginary term (loss factor) of the complex permittivity of the halogen-based plastic increases, for example, 75 ° C in the case of vinyl chloride Above, the temperature below the temperature at which the halogen-based plastic begins to undergo a thermal decomposition reaction and starts releasing hydrogen halide, for example, wind in the temperature range of 210 ° C. or less in the case of vinyl chloride directly Since it can be heated, the heating time can be further shortened.

  16 is a cross-sectional view similar to FIG. 14 for explaining still another configuration example of the preheating device using waste heat shown in FIG. In FIG. 16, teeth 21 with holes are attached to the exit side (right end) of the spiral conveyor 9 shown in FIG. This tooth 21 makes it possible to extrude and crush the heated crushed plastic into fine particles. In this case, since crushing plastic self-heats because it is pressure-molded, it also has an effect of saving energy.

  Next, the configuration of a dehalogenation apparatus such as a halogen-based plastic constituting the heat treatment system of the present invention will be described.

[Batch microwave dehalogenation equipment]
17A is a cross-sectional view in which the central portion of the batch-type microwave application dehalogenation apparatus is cut by a plane parallel to the door, and FIG. 17B is a cross-sectional view in which the central portion of FIG. 17A is cut by a plane perpendicular to the door. It is. In FIG. 17A and FIG. 17B, the code | symbol 23 is a process chamber (applicator), and is comprised by the metal wall. The applicator 23 has a hole in the ceiling. In this hole, a pipe 30 for collecting hydrogen halide is fitted from the outside, and hydrogen halide generated by heating the halogen-based plastic is introduced into a neutralization treatment apparatus to be described later. Make it harmless. The door 32 opens and closes in order to put the container 2 in and out of the apparatus, and is provided on the front surface of the applicator 23 (metal wall in front of FIG. 17A).

  In addition, the applicator 23 has one hole on each of the left and right and back side surfaces, and microwaves are supplied from each hole. Although the total number of microwave power feeding units has been described as three, it is not necessary to be limited to this, and one or a plurality of microwave feeding units may be used. A microwave generation device (magnetron) 26 is installed in the microwave supply portion. Reference numeral 27 denotes an antenna of the magnetron 26, reference numeral 28 denotes a waveguide, and reference numeral 29 denotes a partition plate made of a material that transmits microwaves, such as quartz or ceramics. The partition plate 29 prevents corrosive gas from leaking to the antenna side of the magnetron.

  17A, a stirrer blade 24 made of metal is arranged on the left and right side surfaces of the applicator 23 to disturb the standing wave caused by the microwaves in the applicator 23 so as to minimize the heating unevenness. Each stirrer blade 24 is configured to rotate. It should be noted that the position (distance) from the side surface of the stirrer blade 24, the size shape, the rotational speed, etc. are not necessarily the same on the left and right.

  The crushed plastic 1 which is an object to be heated is put in a container 2 and placed on a table 75 made of ceramics such as ceramics, various bricks or glass. The crushed plastic 1 may be either preheated or not preheated.

  In FIG. 17A and FIG. 17B, a non-contact temperature sensor for monitoring the surface temperature of the crushed plastic is attached, although not particularly shown. And hot air is sent into the applicator 23 through the hot air introduction pipe 33. Here, a metal net or punching metal 34 is attached for the purpose of preventing microwave leakage. If the hot air uses waste heat, it becomes an inexpensive energy source. With such a configuration, the dehalogenation treatment of the crushed plastic is advanced. Hereinafter, this dehalogenation process will be described.

(1) When the crushed halogen-based plastic is put into the apparatus without preheating (A) The temperature of the hot air, the lower limit is the temperature point at which the temperature gradient of the imaginary term (loss factor) of the complex permittivity of the halogen-based plastic increases The upper limit is the temperature at which the halogen-based plastic undergoes a thermal decomposition reaction and the carbon-carbon bond is broken:
(For example, in the case of vinyl chloride, hot air with a lower limit of 75 ° C. and an upper limit of 350 ° C.)
In the case of vinyl chloride, the practical set hot air temperature is between 200 ° C and 300 ° C in the applicator. The crushed halogen plastic absorbs the irradiated microwave and generates heat, and the temperature rises from the inside. Therefore, the microwave output and the temperature of the hot air are combined so as not to exceed the temperature at which the carbon-carbon bond is broken, taking into account both the temperature of the hot air and the heat generated by the microwave absorption.

  When heated at such a temperature, the crushed halogen-based plastic generates heat by absorbing microwave power, rapidly rises above the thermal decomposition start temperature, and releases hydrogen halide rapidly. If all halogens bonded to carbon atoms are separated in the structure of halogen-based plastic, the amount of heat generated by microwaves will be drastically reduced. The temperature of the plastic is about the same as that of hot air.

  Even if it falls to the same temperature as hot air, it is a temperature at which halogen can be separated by pyrolysis, so monitor the temperature of the crushed halogen-based plastic with a non-contact temperature sensor, and if the rise in surface temperature stops, When the surface temperature starts to decrease, it can be recognized that the decomposition has been completed, and the microwave supply can be stopped. Then, immediately after stopping the microwave, or in order to further ensure the separation of the halogen, after giving a little time for heating with only hot air, the treated plastic is taken out from the apparatus.

(B) The temperature of the hot air is the temperature point at which the temperature gradient of the imaginary term (loss factor) of the complex dielectric constant of the halogen-based plastic increases, and the upper limit is the temperature between carbon and halogen due to the thermal decomposition of the halogen-based plastic. For the temperature at which the bond breaks:
(For example, in the case of vinyl chloride, use hot air with a lower limit of 75 ° C. and an upper limit of 210 ° C.)
In the case of vinyl chloride, a practical set hot air temperature is between 150 ° C. and 200 ° C. in the applicator. The crushed halogen plastic absorbs the irradiated microwave and generates heat, and the temperature rises from the inside. Therefore, the microwave output and the temperature of the hot air are combined so as not to exceed the temperature at which the carbon-carbon bond is broken, taking into consideration both the temperature of the hot air and the heat generated by the microwave absorption. That is, larger microwave power than in the case of (A) can be supplied.

  When heated at such a temperature, the crushed halogen-based plastic generates heat by absorbing microwave power, rapidly rises above the thermal decomposition start temperature, and releases hydrogen halide rapidly. If all halogens bonded to carbon atoms are separated in the structure of halogen-based plastic, the amount of heat generated by microwaves will be drastically reduced. The temperature of the plastic is about the same as that of hot air.

  Therefore, the temperature of the crushed halogen-based plastic is monitored with a non-contact temperature sensor, and when the surface temperature stops rising or starts to decrease, it is recognized that the decomposition is complete, and the microwave supply is stopped. it can. In the case of this method, immediately after stopping the microwave, or in order to further ensure the separation of the halogen, a little time for heating with hot air is given, and the temperature of the plastic is higher than the thermal decomposition start temperature of 220 ° C. When low, remove the treated plastic from the equipment.

  The above (A) and (B) are explanations assuming the case of only halogen-based plastics. In the case of so-called general waste plastics mixed with other plastics, the softening point (melting point) of other plastics is compared with the thermal decomposition temperatures of halogen-based plastics. If it is low, the upper limit of the hot air temperature may be treated by the method (A) or (B) as the softening point (melting point) of other plastics.

(2) In the case where the crushed halogen-based plastic is preheated and put into the apparatus, the case where the crushed halogen-based plastic preheated by the method shown in FIGS. 13 to 16 is dehalogenated by the apparatus shown in FIG. Can be processed by the method described in (A) of (1) or (B) of (1). Since the completion of the treatment is controlled by the temperature of the crushed halogen-based plastic monitored by the temperature sensor, the decomposition reaction is completed as soon as it is preheated.

  The point to be emphasized here is that in (1), in order to complete the thermal decomposition quickly, the conventional heating method was used in combination to shorten the microwave heating time. In the case of crushed halogen-based plastics, hot air is not necessarily required.

  Hereinafter, another batch-type microwave dehalogenation apparatus according to the present invention will be described with reference to FIGS. 18, 19 and 20. FIG. The difference from the dehalogenation apparatus shown in FIGS. 17A and 17B is that an electric heater is added. FIG. 18 is a cross-sectional view similar to FIG. 17B for explaining the configuration of another batch type microwave dehalogenation apparatus according to the present invention. FIG. 19 is a cross-sectional view similar to FIG. 17B illustrating the configuration of still another batch-type microwave application dehalogenation apparatus according to the present invention. FIG. 20 is a cross-sectional view similar to FIG. 17B for explaining the configuration of still another batch-type microwave application dehalogenation apparatus according to the present invention. FIG. 21 is a plan view illustrating details of the upper heater used in FIG.

  In FIG. 18, FIG. 19 and FIG. 20, a heater is added in addition to the hot air, but the introduction of the hot air is stopped and only the heater may be used. The difference between FIG. 18 and FIG. 19 is the attachment position of the heater. In FIG. 18, it contacts the applicator outside the applicator. Further, FIG. 19 is in contact with the applicator inside the applicator. In FIG. 20, a heater is placed in the applicator, and the crushed halogen-based plastic is heated from above, so that it can be added to the structure of FIG. 19 as shown.

  The difference between hot air and electric heaters is that hot air is difficult to control temperature, whereas electric heaters are easy to do. Since waste heat can be used directly with hot air, the base temperature should be hot air that uses waste heat, and temperature control is required. For example, the temperature of waste plastic is set near the upper limit of the set temperature using the conventional heating method. When an electric heater is used for the portion to be heated as much as possible, the microwave irradiation time can be shortened.

  A third embodiment of the present invention will be described with reference to FIGS. In Example 3, the turntable 41 was provided in the applicator 23, and the rotation table 41 was rotated to eliminate uneven heating due to microwaves. 22A is a cross-sectional view taken along a plane perpendicular to the door for explaining the basic structure of the turntable system according to the third embodiment of the present invention, and FIG. 22B is a door for explaining the basic structure of the turntable system shown in FIG. 22A. It is sectional drawing in a parallel surface. Although there is a difference in adopting the turntable 41 as the microwave stirring means, the method for separating the halogen from the crushed halogen-based plastic by thermal decomposition is the same as described in FIGS. 17A and 17B.

  FIG. 23A is a cross-sectional view similar to FIG. 22A illustrating a structure in which an electric heater is added to the structure of FIGS. 22A and 22B. FIG. 23B is a cross-sectional view similar to FIG. 22B on a plane parallel to the door for explaining the basic structure of the turntable system shown in FIG. 23A. This structure is the same as that of FIG. 20 adopting the stirrer type, and it is obvious that the same effect can be expected.

  In FIG. 17A to FIG. 20 described above, a method is adopted in which a stirrer blade that stirs microwaves is placed in an applicator and is rotated to improve heating unevenness due to microwaves. On the other hand, in FIG. 22A and FIG. 23B, a container containing crushed halogen-based plastic placed on a turntable is rotated together with the turntable to improve heating unevenness due to microwaves. Although not shown, it goes without saying that if the stirrer blade and turntable are combined, the uneven heating by microwaves can be further improved.

  FIG. 24 is a cross-sectional view taken along a plane perpendicular to the door, illustrating an advanced structure of the turntable system of the present invention. That is, the electric heater shown in FIG. 23 is directly placed in the container 2 containing the crushed halogen-based plastic 1, and the turntable 41 is rotated. As a result, the crushed halogen-based plastic 1 can be mechanically stirred, so that heat from the hot air or the heater can be quickly transmitted to the entire crushed halogen-based plastic 1.

  In FIG. 24, a structure in which the pulverized halogen-based plastic is stirred mechanically using an electric heater is used, but it is not necessary to be an electric heater because hot air can be transmitted evenly, and it can be scraped with either metal or ceramics. If you have the ability to mix, you can reach your goals.

  FIG. 25 is a cross-sectional view taken along a plane perpendicular to the door, illustrating a further developed structure of the turntable system of the present invention. In this structure, by adding a stirrer to FIG. 24 and stirring the microwave, the fixed part, that is, the surface of the electric heater that directly stirs the crushed halogen-based plastic (not a heater, but simply made of a metal as a stirring rod). Is used, the surface is heated by microwaves under the influence of the standing wave of the microwave generated on the surface), and the temperature is partially increased.

  FIG. 26A is a cross-sectional view taken along a plane passing through the axis of a spiral conveyor, illustrating the structure of the fifth embodiment of the present invention. FIG. 26B is a cross-sectional view showing a fractured surface along the line AB in FIG. 26A. The crushed halogen plastic or mixed plastic 1 containing halogen plastic is put into a metal hopper 45. Reference numeral 44 denotes a metal lid, which is a structure for batch processing. In the case of continuous charging, microwaves do not pass through the lid 44, but a hole through which the crushed plastic can pass may be formed.

  The motor 53 rotates the connected spiral conveyor 54. Reference numerals 46, 47, 48, and 49 are ceramics, which together form a hollow cylindrical body, and together with the motor 53 and the spiral conveyor 54, have the function of moving the crushed plastic from left to right in FIG. 26A.

  The reason why the hollow cylindrical body is formed of ceramics is that this part must be irradiated with microwaves, and the spiral conveyor 54 is required to be made of metal due to its required function and strength. This is because when the hollow cylindrical body 54 contacts or approaches is also a metal, there is a high possibility that microwave sparks are generated at the contact portion or the approaching portion. By using ceramics, microwaves propagate inside the ceramics, so that microwaves can be irradiated over a wide area.

  On the other hand, the metal plate 50, 51, 52 is the main structure of the applicator on which the microwave acts. Therefore, the structure of the spiral conveyor 54 is also inside the applicator. Of course, if the inner diameter of the cylindrical portion is large enough to transmit microwaves, that portion must also be considered as an applicator.

  For example, a portion where the crushed plastic 1 is taken into the spiral conveyor 54 from the hopper 45 is usually drowned, but this inner diameter does not necessarily have to be reduced to a diameter that blocks microwaves. This is because if the microwave passes through the hopper 45 and is used as energy for heating the crushed plastic 1, it will not be wasted.

  Hydrogen halide which is generated as a product of thermal decomposition is discharged from the pipes 56 and 58. Although connection of this portion is not shown, transmission of microwaves can be prevented by sandwiching a metal mesh or punching metal. The pipe 55 through which the processed crushed plastic is discharged has a structure that prevents microwave leakage by increasing the inner diameter to prevent microwave transmission. However, since it is not always necessary for the 55 to be in the form of a pipe and the processing completion crushing plastic 62 is sequentially put into the tray 61, the portion 55 is made a large container, that is, the bottom of the pipe is closed to store the processing completion plastic. It may be a structure.

  The microwave supply portion includes a magnetron 26, an antenna 27, a waveguide 28, and a partition plate 29. As a heating method by the conventional heating method, a method using an electric heater is adopted in Example 5, but there is a method using hot air using waste heat. Since the principle that halogen is separated from the crushed halogen-based plastic, the microwave heating and the combined use with the conventional heating method have already been described, they are omitted here.

  In FIG. 26A, the spiral conveyor 54 is described as being placed horizontally. However, for example, when vinyl chloride is processed, the generated hydrogen chloride is light. Therefore, in FIG. If the structure is arranged obliquely and the crushed plastic moves upward while being heated, the generated hydrogen chloride can be discharged smoothly.

  FIG. 27A is a cross-sectional view taken along a plane passing through the axis of a spiral conveyor, illustrating the structure of Example 6 of the present invention. FIG. 27B is a cross-sectional view showing a fractured surface along the line AB in FIG. 27A. In Example 6, the structure described in FIG. 15 and the structure shown in FIGS. 26A and 26B are combined to enable continuous dehalogenation. The description of this embodiment overlaps with FIG. 15, FIG. 26A and FIG.

  FIG. 28 is a cross-sectional view for explaining an example of a neutralization apparatus for neutralizing hydrogen halide generated in the dehalogenation apparatus of each embodiment of the present invention. In FIG. 28, air and hydrogen halide from the dehalogenation apparatus indicated by the arrow 63 are taken into the neutralization tank 65 through the pipe 64. The neutralization tank 65 is filled with an alkaline solution 66 such as sodium hydroxide or calcium hydroxide. The hydrogen halide introduced together with the air reacts with the alkaline solution 66 and becomes a neutralized salt 67 such as sodium halide or calcium halide and precipitates at the bottom of the neutralization tank 65.

  A vacuum pump 69 is employed so that the inside of the neutralization tank 65 has a negative pressure and the generated gas is quickly taken into the neutralization tank 65. The neutralization processing completion air 68 is discharged through the pipe 70 by the vacuum pump 69 in the neutralization processing completion air discharge direction indicated by the arrow 71.

  By assembling this neutralization apparatus with any of the above-described embodiments, it is possible to provide a thermal decomposition treatment system for a desired microwave-applied halogen-based plastic.

It is explanatory drawing in the case of using a waste halogen-type plastic as a substitute for coke for reducing agents, such as iron ore. It is the flowchart of the process estimated from the conventional waste plastic dechlorination processing system. It is the result of putting the 5 cm cube plastic in the circulating hot air type thermostat set to 100 ° C. and measuring the temperature with respect to the elapsed time. It is a figure explaining the molecular structure of vinyl chloride and the skeleton structure after dechlorination. It is a figure explaining the temperature change of the complex dielectric constant (imaginary term) of vinyl chloride. It is a figure explaining the relationship between microwave irradiation time and the temperature of vinyl chloride. It is a figure explaining the relationship between microwave irradiation time and the temperature rise speed of vinyl chloride. It is explanatory drawing of the thermal decomposition by the conventional heating method. 2 is a flow diagram of a basic process for microwave heating a crushed halogenated or non-halogenated plastic mixture. It is a flowchart of the process of performing microwave heating, after heating the mixture of the halogen-type plastics or non-halogen-type plastics by heating means other than microwave heating. It is a flowchart explaining the system which switches the mixture of the crushed halogen plastic or non-halogen plastic to microwave heating after heating by the conventional heating method. It is a flowchart explaining the system which adds microwave heating, after pre-heating the mixture of the crushed halogen-type plastic or non-halogen-type plastic more than a phase transition temperature with the conventional heating method. It is sectional drawing explaining the container for batch type microwave application dehalogenation apparatuses which put the crushed plastic. It is sectional drawing explaining the structural example of the preheating apparatus of a crushing halogen-type plastic. It is sectional drawing of FIG. 13 explaining the apparatus which preheats the crushing plastic 4 using the heating fluid using waste heat instead of a heater in the preheating apparatus shown in FIG. It is sectional drawing similar to FIG. 14 explaining the other structural example of the preheating apparatus by waste-heat utilization shown in FIG. FIG. 15 is a cross-sectional view similar to FIG. 14 for explaining still another configuration example of the preheating device using waste heat shown in FIG. 14. It is sectional drawing which cut | disconnected the center part of the batch type microwave application dehalogenation apparatus by the surface parallel to a door. It is sectional drawing which cut | disconnected the center part of FIG. 17A by the surface at right angles to a door. It is the same sectional drawing as FIG. 17B explaining the structure of another batch type microwave application dehalogenation apparatus by this invention. FIG. 18 is a cross-sectional view similar to FIG. 17B illustrating the configuration of still another batch-type microwave application dehalogenation apparatus according to the present invention. FIG. 18 is a cross-sectional view similar to FIG. 17B for explaining the configuration of yet another batch-type microwave application dehalogenation apparatus according to the present invention. It is a top view explaining the detail of the upper heater used in FIG. It is sectional drawing in the surface at right angles to the door explaining the basic structure of the turntable system of Example 3 of this invention. It is sectional drawing in the surface parallel to the door explaining the basic structure of the turntable system shown to FIG. 22A. It is sectional drawing similar to FIG. 22A explaining the structure which added the electric heater to the structure of FIG. 22A and FIG. 22B. It is sectional drawing similar to FIG. 22B in the surface parallel to the door explaining the basic structure of the turntable system shown to FIG. 23A. It is sectional drawing in the surface at right angles to the door explaining the development type structure of the turntable system of this invention. It is sectional drawing in the surface at right angles to the door explaining the further developed type structure of the turntable system of this invention. It is sectional drawing in the surface which passes along the axis | shaft of the spiral conveyor explaining Example 5 structure of this invention. It is sectional drawing which shows the torn surface along the AB line | wire of FIG. 26A. It is sectional drawing in the surface which passes along the axis | shaft of the spiral conveyor explaining Example 6 structure of this invention. It is sectional drawing which shows the torn surface along the AB line of FIG. 27A. It is sectional drawing explaining an example of the neutralization apparatus for neutralizing the hydrogen halide generated with the dehalogenation apparatus of each Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Crushed halogen plastic, 2, 4 ... Container, 5 ... Hopper, 7 ... Heater, 8 ... Motor, 9 ... Spiral conveyor, 11 ... Heated crush Halogen plastic, 15 ... hollow cylindrical part, 21 ... tooth, 23 ... applicator, 24 ... stirrer blade, 26 ... magnetron, 27 ... antenna, 28 ... waveguide Tube ... 29 microwave transmission partition plate, 30 ... hydrogen halide collection tube, 32 ... door, 33 ... hot air introduction tube, 34 ... microwave leakage prevention metal mesh or punching metal, 36 ... Heater, 37 ... Thermal insulation cover, 38 ... Metal heater cover, 39 ... Upper heater, 41 ... Turntable, 42 ... Turntable rotation motor, 43 ...・ Stirring bar (heater available), 44 ... hopper lid, 45 ... hopper, 65 ... neutralization tank.

Claims (11)

A thermal decomposition treatment system for thermally decomposing halogen-based plastics using microwaves,
The pyrolysis processing system has microwave heating means and heating means other than microwave heating,
The heating means other than the microwave heating is such that the lower limit of the set temperature is at or near the temperature point at which the temperature gradient of the imaginary term (loss coefficient) of the complex dielectric constant of the halogen-based plastic increases. Is the temperature at which the carbon-carbon bond in the molecular structure formula of the halogen-based plastic is separated by heat,
A thermal decomposition treatment system characterized in that the halogen-based plastic is decomposed by using a heating means other than the microwave heating in combination with the microwave heating means.   The thermal decomposition treatment system according to claim 1, wherein the heating means other than the microwave heating is a heater, hot air, or a heater and hot air.   The lower limit of the set temperature of the heating means other than the microwave heating is a temperature point at which the temperature gradient of the imaginary term (loss factor) of the complex dielectric constant of the halogen-based plastic increases, and the upper limit of the set temperature is that of the halogen-based plastic The thermal decomposition treatment system according to claim 1, wherein the temperature is a temperature at which the hydrogen halide begins to be separated by heat. Temperature detecting means for detecting the temperature of at least part of the internal temperature or surface temperature of the halogen-based plastic,
The set temperature of the heating means other than the microwave heating is set to a temperature equal to or higher than the temperature point at which the temperature gradient of the imaginary number term (loss factor) of the complex permittivity of the halogen-based plastic increases, and the halogen-based plastic is heated,
After the temperature detected by the temperature detecting means reaches a temperature higher than the temperature at which the temperature gradient of the loss coefficient becomes larger and lower than a temperature at which separation of hydrogen halide by heat is started, the microwave of the microwave heating means Irradiation is started, The thermal decomposition processing system of Claim 1 characterized by the above-mentioned.   After the heating of the halogen-based plastic by the heating means other than the microwave heating, the detection temperature of the temperature detection means is equal to or higher than the temperature at which the temperature gradient of the loss coefficient of the halogen-based plastic is increased, and the thermal decomposition reaction 5. The heating by the heating means other than the microwave heating is stopped substantially simultaneously with the start of the microwave irradiation of the microwave heating means after reaching a temperature at which the temperature of the microwave heating means is reached. Pyrolysis treatment system. A thermal decomposition treatment system for thermally decomposing a mixture of halogen-based plastics including non-halogen-based plastics by applying microwaves,
Heating means other than microwave heating and microwave heating means, and temperature detection means for detecting the internal temperature of the mixture to be pyrolyzed or the temperature of at least a part of the surface,
The set temperature of the heating means other than the microwave heating is equal to or higher than the temperature point at which the temperature gradient of the imaginary term (loss factor) of the complex dielectric constant of the halogen-based plastic increases.
The lower limit of the detection temperature of the mixture by the temperature detection means is a temperature point at which the temperature gradient of the loss coefficient of the halogen-based plastic increases, and the upper limit of the detection temperature is the thermal decomposition start temperature of the halogen-based plastic or the mixture. The lowest softening temperature point of the non-halogen plastics contained, whichever is lower,
After the temperature detected by the temperature detecting means of the mixture by the heating means other than the microwave heating reaches the upper limit, microwave irradiation by the microwave heating means is started and thermal decomposition is started. Disassembly processing system.   After starting heating of the mixture by a heating means other than the microwave heating, the temperature detected by the temperature detection means is equal to or higher than the temperature point at which the temperature gradient of the loss coefficient of the halogen-based plastic contained in the mixture increases, and After reaching a temperature lower than the temperature at which the halogen-based plastic undergoes a thermal decomposition reaction or the lowest softening temperature point of the non-halogen-based plastic, the microwave heating means starts microwave irradiation. The thermal decomposition treatment system according to claim 6, wherein heating by a heating means other than the microwave heating is stopped substantially simultaneously.   8. The microwave irradiation by at least the microwave heating unit is stopped when the time change of the detected temperature by the temperature detecting unit becomes at least zero or negative. The thermal decomposition processing system according to crab.   9. A pulverizer for processing the halogen-based plastic or the mixture of the halogen-based plastic and the non-halogen-based plastic into particles, flakes, chips, or powders. The thermal decomposition processing system according to crab.   The halogen-based plastic is a film and contains earth and sand, or a mixture containing at least one of the halogen-based plastic and the non-halogen-based plastic and containing earth and sand and dust is granular, flake, chip, or powder. The thermal decomposition treatment system according to any one of claims 1 to 8, further comprising pressure forming processing means for processing into a shape. 9. A solidifying means for sucking the separated hydrogen halide under reduced pressure and introducing it into an aqueous alkali solution to solidify it into a safe form of sodium halide or calcium halide. The thermal decomposition processing system in any one of.

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