Heating apparatus

Abstract

To provide a heating apparatus that is capable of efficiently separating other inorganic substances from a plastic material layer being a material of a solar panel or the like by thermally decomposing the layer without making a structure of the heating apparatus equipped with a furnace complicated.SOLUTION: By heating the inside of a heating furnace 1 by a heating source 1a in the state where the inside of the heating furnace 1 is made vacuum or is filled with nitrogen, a plastic material layer constituting materials 2 housed inside the heating furnace 1 is thermally decomposed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a heat treatment facility capable of efficiently separating a plastic material layer from other inorganic substances by thermally decomposing equipment including the plastic material layer.

Background Art

[0002] The Paris Agreement, which came into force in 2016, aims to peak greenhouse gas emissions as soon as possible and to make efforts to suppress the rise in the world's average temperature. The goal of reducing greenhouse gas emissions is entrusted to each country, and our country aims to reduce emissions by 26% in 2030 compared to 2013 (25.4% compared to 2005).

[0003] Under such an international trend, various measures are being taken to achieve the above reduction targets. One of them is to promote an increase in the introduction of renewable energy such as solar power generation that can suppress greenhouse gas emissions.

[0004] As a result, the introduction of solar power generation has increased and reached 71 GW in cumulative terms by the end of 2020. The domestic shipments of solar cell modules (solar panels) used for solar power generation have turned to an increasing trend since fiscal 2009, following the start of the surplus power purchase system for solar power generation in November 2009. Due to the effect of the feed-in tariff system that started in 2012, the introduction of solar power generation systems in the non-residential sector has rapidly expanded.

[0005] As future introduction targets, in the long-term energy supply and demand outlook announced in July 2015, 64 GW is shown for both residential and non-residential use in 2030. In the "PV OUTLOOK 2050" of the Japan Photovoltaic Energy Association (JPEA), 100 GW is shown for 2030 and 200 GW is shown for 2050.

[0006] On the one hand, the disposal of solar panels used in large-scale photovoltaic power generation is being regarded as a problem. At present, although the discharge of solar panels has not yet become a serious issue, it is estimated that approximately 4,400 [t] are discharged annually due to defective panels, construction defects, damage caused by natural disasters, and replacements.

[0007] In addition, the product life of solar panels is assumed to be about 25 to 30 years, and a large amount of discharges of power generation equipment such as used solar panels are expected around 2040 when the power generation business recognized under the Feed-in Tariff (FIT) system ends.

[0008] Regarding the future estimated discharge amounts, there are various estimations. According to the estimation conducted by the Ministry of the Environment, if the product life is assumed to be 25 years, it will reach approximately 780,000 [t] in 2039, which will account for 6% of the final disposal amount of industrial waste.

[0009] Regarding this large amount of discharge, concerns are increasing about the abandonment and illegal dumping of solar panels, the problem of the outflow and diffusion of harmful substances from solar panels caused by this, and the congestion of final disposal sites.

[0010] Therefore, in order to prevent the occurrence of these various problems and suppress the environmental load, the reuse and recycling of products are recommended. Reuse can reduce the final disposal amount of solar panels and so on, and can reduce the natural resources required for the manufacture of new solar panels. Recycling is effective in preventing the depletion of natural resources.

[0011] As a recycling technology for solar panels, for example, the technology described in Patent Document 1 below is disclosed.

Prior Art Document

Patent Document

[0012]

Patent Document 1

[0013] The recycling technology described in the above Patent Document 1 relates to a pyrolysis apparatus for pyrolyzing a plastic material layer used in a solar panel or the like. The solar panel includes a solar cell held by a plastic material layer on one side of a cover glass, and a wiring member connected to the solar cell. By pyrolyzing the plastic material layer in a heating furnace, the cover glass, the solar cell, and the wiring member are separated.

[0014] The pyrolysis in the heating furnace prevents a fire in the furnace by heating the plastic material layer in a heating steam atmosphere containing almost no oxygen. Further, the furnace body has a double structure of an inner wall member and an outer wall member, and by providing a heat storage material layer between the inner wall member and the outer wall member, when superheated steam is introduced into the inner wall member to raise the temperature inside the inner wall member, it can be structured to store heat in the heat storage member, and when repeatedly performing the thermal decomposition treatment of the panel, the time required to bring the temperature inside the inner wall member after replacing the panel to a desired temperature can be shortened.

Summary of the Invention

Problems to be Solved by the Invention

[0015] However, the above-described conventional pyrolysis apparatus needs to supply superheated steam into the furnace in order to prevent a fire in the furnace, and in order to generate superheated steam, it is necessary to provide a superheated steam generator.

[0016] This heating steam generator is equipped with a pure water maker for supplying pure water to it, and this pure water maker requires at least a raw water passage for supplying raw water such as tap water, groundwater, and industrial water, and a pure water supply passage for supplying pure water from the pure water maker to the superheated steam generator. Therefore, the structure of the equipment becomes complicated and the cost increases. Further, when a reserve tank for storing pure water is provided, the further complication of the structure and the increase in cost become remarkable.

[0017] Also, the temperature inside the furnace by superheated steam is preferably 600°C or higher, and it has to be made very high, and a high superheating capacity is required for the superheated steam generator.

[0018] In view of the above problems, the present invention aims to provide a heat treatment facility that can efficiently separate other inorganic substances by reliably thermally decomposing and vaporizing a plastic material layer constituting a solar panel or the like without complicating the structure of the heat treatment facility including a furnace.

Means for Solving the Problems

[0019] The heat treatment facility according to the invention described in claim 1 includes a heating furnace that houses and heats a device including at least a plastic material layer, and is characterized in that the plastic material layer housed in the heating furnace is thermally decomposed by heating the inside of the heating furnace under a vacuum or in a state filled with nitrogen.

[0020] The heat treatment facility according to the invention described in claim 2 is characterized in that the plastic material layer according to claim 1 is EVA (ethylene vinyl acetate), and the heating furnace includes a heater that heats the inside of the heating furnace, and the EVA (ethylene vinyl acetate) is thermally decomposed by heating the inside of the heating furnace to 200°C to 500°C with the heater.

[0021] The heat treatment facility according to the invention described in claim 3 is characterized in that it is configured to include a condenser that cools, condenses, and retains the gas generated by the thermal decomposition of the plastic material layer according to any one of claims 1 or 2.

[0022] The heat treatment facility according to the invention described in claim 4 is characterized in that it is configured to include an exhaust gas treatment device that adsorbs and removes the malodorous components of the gas that has passed through the condenser according to claim 3.

Effects of the Invention

[0023] According to the invention described in claim 1, since the inside of the heating furnace is in a vacuum or nitrogen-filled state and the plastic material layer is heat-treated, generation of carbon dioxide can be reliably prevented when the plastic material layer is thermally decomposed. In addition, compared with conventional devices, the structure can be simplified and the cost can be suppressed.

[0024] Moreover, since the inside of the heating furnace is in a state filled with vacuum or nitrogen, no accident such as a fire occurs in the heating furnace when heating the plastic material layer.

[0025] According to the invention described in claim 2, by heat-treating EVA (ethylene vinyl acetate) as the plastic material layer, the heating temperature in the furnace can be suppressed to about 200°C to 500°C, and the heating performance of the heater can be set low.

[0026] According to the invention described in claim 3, since the gas generated by the thermal decomposition of the plastic material layer is cooled and condensed and retained in the condenser, harmful components can be removed from the generated gas.

[0027] According to the invention described in claim 4, by providing an exhaust gas treatment device, the malodorous components of the gas passing through the condenser can be adsorbed and removed, and it is not discharged into the atmosphere.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0029] Hereinafter, an embodiment of the heat treatment equipment according to the present invention will be described with reference to FIGS. 1 and 2. In FIG. 1, reference numeral 1 denotes a heating furnace constituting the heat treatment equipment A, and one side is provided with an opening / closing door 3 for opening and closing an opening through which a member 2 including at least a plastic material layer, such as a solar panel constituting a solar power generation equipment to be recycled, is taken in and out.

[0030] At the upper part, an air supply pipe 4 and an exhaust pipe 5 are led out outward through an upper wall body. Further, the heating furnace 1 is provided with a heating source 1a composed of an electric heater or the like for heating so that the inside of the furnace reaches a set temperature.

[0031] A nitrogen gas cylinder 6 is connected to the air supply pipe 4, and the supply and stop of nitrogen gas to the heating furnace 1 are switched by opening and closing an on-off valve 7 provided on the air supply pipe 4. A condenser (condenser) 8, an exhaust pump 9, and a deodorizing device 10 are respectively connected in series to the air distribution pipe 5 by piping.

[0032] A refrigerant circulation device 11 for cooling and condensing the decomposition gas flowing through the condenser 8 is connected to the condenser (condenser) 8 by circulating the decomposition gas discharged from the heating furnace 1 through the condenser 8.

[0033] In addition, the condenser 8 is provided with a drain a for discharging the liquid that has been brought to room temperature by the circulation of the refrigerant and stays in the condenser 8. The liquid discharged by opening this drain a is enclosed in a sealed container (not shown) and recovered.

[0034] The exhaust pump 9 is configured to incorporate, for example, a turbofan, and is used to make the inside of the heating furnace 1 in a vacuum state or to forcibly discharge the decomposition gas generated in the heating furnace 1. Since the exhaust pump 9 does not have the function of condensing the decomposition gas, it is not affected by the adverse effects of the decomposition gas.

[0035] As shown in FIG. 2, the deodorizing device 10 deodorizes the malodor contained in the decomposition gas to enable clean exhaust to the outside. For example, an ozone generator 10a, activated carbon 10b, an aldehyde adsorbent 10c mainly composed of activated carbon, a deodorizing catalyst 10d that decomposes excess ozone to prevent it from being discharged into the atmosphere, and a blower 10e are effectively arranged to purify the malodor.

[0036] Reference numeral 12 shown in FIG. 1 is a circulation pump. After sending the hot air in the heating furnace 1 to the condenser 6 for cooling and then returning the cold air to the heating furnace 1 through the supply pipe 13, the inside of the heating furnace 1 is returned to room temperature. At this time, the exhaust pipe 5 and the supply pipe 13 are in a communicating state by switching a flow path switching valve b1.

[0037] Reference numeral 14 shown in FIG. 1 is a carrier for placing the equipment 2 to be carried into the heating furnace 1, and is used when loading and unloading the equipment 2 into and out of the heating furnace 1.

[0038] Next, the operation when the equipment 2 is heat-treated by the heat treatment facility A shown in FIG. 1 will be described. The equipment 2 to be processed according to the present invention is equipment including at least a plastic material layer, such as a solar panel of a solar power generation facility, and the equipment 2 is placed on the carrier 14 outside the heating furnace 1 for recycling purposes. The equipment 2 on the carrier 14 is carried into the heating furnace 1 in a state of being placed on the carrier 14 through the opening opened by opening the opening and closing door 3 of the heating furnace 1. After the equipment 2 is carried in, the opening and closing door 3 is operated again to close the opening of the heating furnace 1. In a state where the opening and closing door 3 is closed, the inside of the heating furnace 1 becomes airtight.

[0039] After accommodating the equipment 2 to be heat-treated in the heating furnace 1 as described above, the exhaust pump 9 is driven to evacuate the inside of the heating furnace 1 through the exhaust pipe 5 to a vacuum state. Next, after stopping the driving of the exhaust pump 9, the cock 6a of the cylinder 6 is opened, and then, by opening the on-off valve 7, nitrogen gas is sent into the heating furnace 1 through the air supply pipe 4.

[0040] After filling the inside of the heating furnace 1 with nitrogen gas in this way, the cock 6a of the nitrogen gas cylinder 6 is closed and the on-off valve 7 is closed to stop the supply of nitrogen gas into the heating furnace 1. After filling a certain amount of nitrogen gas into the heating furnace 1 in this way, the inside of the heating furnace 1 is heated to a predetermined temperature by the heating source 1a.

[0041] In particular, when the plastic material layer constituting the equipment 2 accommodated in the heating furnace 1 is EVA (ethylene vinyl acetate), the inside of the heating furnace 1 is heated to an arbitrarily set temperature within the range of 200°C to 500°C. When the plastic material layer is other than EVA (ethylene vinyl acetate), it is heated to the temperature at which the plastic material layer thermally decomposes.

[0042] By the heat treatment of the heating furnace 1, the plastic material layer constituting the equipment 2 in the heating furnace 1 thermally decomposes, and the plastic resin constituting the plastic material layer vaporizes. When the equipment 2 including the plastic material layer is a solar panel due to the thermal decomposition of the plastic material resin, the plastic material layer such as the filler, adhesive, and back film of the panel thermally decomposes and is removed, and it is separated into an aluminum frame, cover glass, solar cell, metal wiring member, etc.

[0043] In this state, the exhaust pump 9 is driven again, and the gas (decomposition gas) generated by the vaporization of the plastic resin is discharged outside the heating furnace 1 through the exhaust pipe 5 together with nitrogen gas. Although the decomposition gas and nitrogen gas discharged from the heating furnace 1 flow through the exhaust pipe 5, they do not flow into the supply pipe 13 side by the switching operation of the flow path switching valve b1.

[0044] The decomposition gas and nitrogen gas discharged into the exhaust pipe 5 flow into the condenser 8 and are cooled. Since this condenser 8 is constantly cooled and held by the operation of the refrigerant circulation device 11, the decomposition gas is well cooled and condensed into a liquid state.

[0045] In addition, the remaining gas that has passed through the condenser 8 flows into the deodorizing device 10 by the driving of the exhaust pump 9. In the deodorizing device 10, the malodorous substances considered to be derived from the adhering and decaying substances that are the main factors of most of the malodors contained in the gas can be surely removed by the functions of the deodorizing treatment members composed of the ozone generator 10a, activated carbon 10b, and aldehyde adsorbent 10c that constitute the deodorizing device 10.

[0046] As a result, the exhaust gas that has passed through the deodorizing device 10 can always be discharged into the atmosphere in a purified state, and in the treatment operation of the decomposition gas containing hydrogen chloride, harmful substances and malodorous components can be treated safely and hygienically without being discharged to the outside.

[0047] In addition, since the equipment 2 in the heating furnace 1 thermally decomposes the plastic resin that constitutes the plastic material layer, unlike the case of burning the plastic resin, carbon dioxide is not contained in the decomposition gas. Therefore, carbon dioxide is not discharged to the outside through the exhaust pipe 5, which can contribute to reducing the environmental load. Further, since the heating furnace 1 is filled with nitrogen gas, it is possible to reliably prevent the occurrence of fire in the heating furnace 1 while preventing the generation of the aforementioned carbon dioxide.

[0048] After the plastic resin is thermally decomposed in the heating furnace 1, when the equipment 2 is a solar panel, the aluminum frame, cover glass, solar cell, and metal wiring member are left on the transport cart 14 in the heating furnace 1 in a separated state.

[0049] Subsequently, when the heating operation by the heat source 1a of the heating furnace 1 is terminated, the flow path switching valve b1 is switched so that the exhaust pipe 5 and the supply pipe 13 are in a communicating state. Then, the circulation pump 12 is driven to send the hot air in the heating furnace 1 to the condenser 6 for cooling, and then the cold air is returned into the heating furnace 1 through the supply pipe 13, thereby returning the inside of the heating furnace 1 to room temperature.

[0050] When the inside of the heating furnace 1 reaches room temperature, the opening / closing door 3 of the heating furnace 1 is opened, and the transport cart 14 is carried out of the heating furnace 1 through the opening. The aluminum frame, cover glass, solar cell, metal wiring member, etc. on the carried-out transport cart 14 are recycled. This can solve the problems of the conventional abandonment and illegal dumping of solar panels, the outflow and diffusion of harmful substances from solar panels caused by this, and the concern about the overcrowding of final disposal sites, and can also contribute to preventing the depletion of natural resources.

[0051] Note that the heating furnace 1, the refrigerant circulation device 11, the exhaust pump 9, the deodorizing device 10, the circulation pump 12, and various valves described above are all optimally controlled in terms of temperature, degree of vacuum, gas filling degree, etc. by a controller (not shown), and the heat treatment operation of the equipment 2 is carried out.

[0052] As described above, the heat treatment equipment of the present invention thermally decomposes equipment including a plastic material layer such as a solar panel by heating it at a high temperature in a heating furnace filled with nitrogen gas. Therefore, combustion does not occur in the heating furnace 1, it is possible to prevent carbon dioxide from being contained in the decomposition gas of the plastic material layer, and it is possible to prevent the emission of carbon dioxide into the atmosphere. Further, since it is heated under nitrogen filling, a fire does not occur in the heating furnace.

[0053] Furthermore, by thermally decomposing the plastic material layer constituting the equipment, the equipment can be easily separated into, for example, an aluminum frame, cover glass, solar cell, metal wiring member, etc., and recycling treatment can be efficiently performed. The solar cell can then extract silver etc. by melting.

[0054] Moreover, since the malodorous components of the decomposition gas are surely removed by the deodorizing device, no malodor is emitted into the atmosphere.

[0055] Also, by driving the circulation pump to send the hot air in the heating furnace to the condenser for cooling and then returning the cold air to the heating furnace through the supply pipe, the inside of the heating furnace can be returned to room temperature in a short time, so the recycling treatment work can be made more efficient.

[0056] Note that the present invention is not limited to the above-described embodiments, and it goes without saying that the present invention includes various modified embodiments without departing from the scope of the technical idea of the present invention. For example, in the above-described embodiment, the case where nitrogen gas is filled in the heating furnace and heat treatment is performed to prevent combustion and fire of the plastic material layer is described. However, even if the heating furnace is evacuated without filling nitrogen gas and the plastic material layer is heat-treated, the same effects as described above can be obtained.

Industrial Applicability

[0057] The present invention can be used for heat treatment equipment that thermally decomposes equipment including a plastic material layer.

Explanation of Reference Numerals

[0058] 1 Heating furnace 1a Heat source 2 Equipment 3 Opening and closing door 4 Air supply pipe 5 Exhaust pipe 6 Nitrogen gas cylinder 6a Cock 7 On-off valve 8 Condenser 9 Exhaust pump 10 Deodorizing device 11 Refrigerant circulation device 12 Circulation pump 13 Supply pipe 14 Transfer cart A Heat treatment equipment a Drain b1 Flow path switching valve

Claims

1. A heat treatment facility comprising a heating furnace for accommodating and heating a device including at least a plastic material layer, and pyrolyzing the plastic material layer accommodated in the heating furnace by heating the inside of the heating furnace in a vacuum state or in a state filled with nitrogen.

2. The plastic material layer is EVA (ethylene vinyl acetate), and the heating furnace is provided with a heater for heating the inside of the heating furnace, and the EVA (ethylene vinyl acetate) is pyrolyzed by heating the inside of the heating furnace to 200°C to 500°C by the heater. The heat treatment facility according to Claim 1.

3. The heat treatment facility according to any one of Claims 1 or 2, comprising a condenser for cooling, condensing, and retaining the gas generated by the pyrolysis of the plastic material layer.

4. The heat treatment facility according to Claim 3, comprising an exhaust gas treatment device for adsorbing and removing the malodorous components of the gas that has passed through the condenser.

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