Solid fuel containing waste plastics and method for manufacturing the same

Abstract

To provide a solid fuel containing waste plastics, which generates little chlorine-based gas and can use chlorine-based waste plastics, and a method for manufacturing the same. There is provided a solid fuel containing industrial waste plastics, which comprises a first layer made of a heat-melted product obtained by heating and melting industrial waste plastics in a reducing atmosphere, and a second layer consisting of inorganic fibers and a binder, and which contains 5 to 95 mass% of the industrial waste plastics, 5 to 50 mass% of the inorganic fibers, and 0.5 to 50 mass% of the binder. The industrial waste plastics include polyester resin, polystyrene resin, and polyvinyl chloride resin. The solid fuel has an ash content of 20 mass% or less, fixed carbon of 20 to 30 mass%, and a volatile matter content of 50 to 70 mass%. The ash content includes 5 mass% or less of calcium oxide (CaO), 10 mass% or less of silicon dioxide (SiO2), and 5 mass% or less of aluminum oxide (Al2O3).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a solid fuel containing waste plastics and a method for producing the same. [Background technology]

[0002] Demand for plastics (waste plastics), which are industrial waste, as a fuel raw material is on the rise due in part to the soaring prices of petrochemical fuels, but even so, PVC plastics in particular are still being disposed of in landfills. In recent years, a waste-derived solid fuel called RPF (Refuse Paper & Plastic Fuel) has been released onto the market. RPF is made from waste paper, waste plastics such as polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP), as well as sawdust and wood chips from demolition materials, and has the advantage of having a large calorific value.

[0003] However, when RPF is made from raw materials such as polyvinyl chloride (PVC) or fiber reinforced plastic (FRP), dioxins and chlorine gases are generated, so these chlorine-based plastics cannot be used as raw materials.In addition, although the total chlorine content in RPF-coke is limited to 0.6 mass fraction (%) or less (JIS Z7311:2010), in reality it contains about 0.5 mass fraction (%) of chlorine, which causes corrosion of the boiler walls. Furthermore, RPF is limited in the raw materials it can use, since it cannot use chlorine-containing waste plastics, metals, non-ferrous metals, glass, food, drinking water, etc. Waste plastics that contain large amounts of chlorine cause significant damage to the furnace walls during combustion, shortening the lifespan of the firebricks and causing increased running costs. As a result, chlorine-rich RPF is not widely used, and there is a need to find a way to effectively utilize waste plastics that contain chlorine.

[0004] Patent Documents 1-3 describe a solid fuel that contains pulverized coal obtained from coal and a heat-treated product obtained by heating a thermoplastic containing chlorine. This solid fuel is made by mixing 100 parts by mass of thermoplastic plastic with 50 to 500 parts by mass of pulverized coal, and adjusting the calorific value of the plastic with the pulverized coal, but it is expensive and has problems such as black smoke and dust generation during combustion.

[0005] Industrial waste plastics containing a large amount of chlorine have a problem that they melt or soften during molding and melt into pellets when passed through a perforated iron screen, resulting in poor work efficiency and poor productivity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5549169 specification [Patent Document 2] Patent No. 5549168 specification [Patent Document 3] Patent No. 5759099 specification Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above-mentioned conventional problems, and an object of the present invention is to provide a solid fuel containing waste plastics, which generates little chlorine-based gas and can use chlorine-based waste plastics, and a method for producing the same. [Means for solving the problem]

[0008] The means for solving the above problems are as follows. (1) A solid fuel containing industrial waste plastics, A first layer made of a heat-melted product obtained by heating and melting industrial waste plastic in a reducing atmosphere; A second layer consisting of inorganic fibers and a binder. It consists of: By adjusting the amount of the second layer of inorganic fibers, the specific gravity of this solid fuel can be adjusted and the amount of chlorine contained in the industrial waste plastic in the first layer can be reduced. In addition, since the first layer is made of a heat-melted product obtained by heating and melting the industrial waste plastic in a reducing atmosphere, there is no adhesion to the mold during molding, improving work efficiency and preventing ignition and combustion during manufacturing, thereby preventing fires. Furthermore, it is possible to actively and effectively utilize vinyl chloride-based industrial waste plastics that contain chlorine, reduce the adverse effects of chlorine compounds on the global environment, and by significantly reducing microplastics in the ocean, it helps prevent the destruction of ecosystems. (2) In the above-mentioned means 1, The industrial waste plastic is 5 to 95 mass %, The inorganic fiber material is 5 to 50 mass %, The binder is contained in an amount of 0.5 to 50% by mass. (3) In the above means 1 or 2, The industrial waste plastics include polyester resin, polystyrene resin, and polyvinyl chloride resin. (4) In any one of the above means 1 to 3, The solid fuel contains an ash content of 20 mass % or less, a fixed carbon content of 20 to 30 mass %, and a volatile matter content of 50 to 70 mass %. (5) In the above-mentioned means 4, The ash content includes calcium oxide (CaO) 5% by mass or less, silicon dioxide (SiO2) 10% by mass or less, and aluminum oxide (Al2O3) 5% by mass or less. (6) In any one of the above means 1 to 5, The chlorine content is 0.2 mass% or less. (7) In any one of the above means 1 to 6, The specific gravity is 0.3 to 0.8. (8) In any one of the above means 1 to 7, One of the first layer or the second layer is cylindrical, and the other layer is hollow cylindrical and has an interior extending in an axial direction; The cylindrical one layer is inserted inside the other layer. (9) In any one of the above means 1 to 7, One of the first layer and the second layer has a semi-cylindrical shape, and the other layer has a semi-cylindrical shape and has a groove portion extending in the axial direction, The one layer having a semi-cylinder shape is inserted into the groove of the other layer.

[0009] (10) A method for producing solid fuel containing industrial waste plastics includes the following steps: a first layer forming step of forming a first layer from a main raw material consisting of industrial waste plastic; A second layer forming step of forming a second layer from a secondary raw material made of inorganic fiber material; a bonding step of bonding the first layer and the second layer to form a laminate; Equipped with. (11) In the above-mentioned means 10, The method further includes a drying step of drying the laminate. (12) In the above means 10 or 11, The first layer forming step includes: A quantitative supplying process for supplying a quantitative amount of a main raw material consisting of industrial waste plastic; A mixing and kneading process in which the main raw materials are heated, melted, mixed, and kneaded in a reducing atmosphere; A molding process of extruding the kneaded main raw material into a predetermined shape; Equipped with. (13) In any one of the above means 10 to 12, The second layer forming step includes: a quantitative supplying step of supplying a quantitative amount of an auxiliary material made of inorganic fiber material; The mixing and kneading process involves mixing and kneading the auxiliary materials and binders. A molding process of extruding the kneaded auxiliary material into a predetermined shape; Equipped with. Effect of the Invention

[0010] According to the present invention, there are effects that the generation of chlorine-based gas is small and chlorine-based waste plastics can be used. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view of a solid fuel according to the present invention, in which an inner layer is inserted inside a hollow cylindrical outer layer. FIG. [Diagram 2] FIG. 13 is a perspective view of a modified example of the solid fuel according to the present invention, in which an inner layer is inserted into a groove of a hollow semi-cylindrical outer layer and joined together. [Diagram 3] FIG. 2 is a diagram showing a process for producing the solid fuel shown in FIG. 1. [Figure 4] FIG. 2 is a block diagram of the solid fuel production apparatus shown in FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described.

[0013] 1 shows a solid fuel 1 according to an embodiment of the present invention. The solid fuel 1 comprises an inner layer 2 as a first layer and an outer layer 3 as a second layer.

[0014] The inner layer 2 is made of a heat-melting processed product obtained by heating and melting industrial waste plastic in a reducing atmosphere. The inner layer 2 is cylindrical and is inserted inside the outer layer 3.

[0015] The outer layer 3 is made of inorganic fibers and a binder, and has flexibility. The outer layer 3 is hollow and cylindrical with an inner diameter of 5 to 90 mm and a length of 50 to 150 mm, and has an interior portion extending in the axial direction.

[0016] In the solid fuel 1 of Figure 1, the inner layer 2 of the first layer is cylindrical and the outer layer 3 of the second layer is hollow cylindrical, but as in the solid fuel 1a shown in Figure 2, the inner layer 2 of the first layer may be semi-cylindrical and the outer layer 3 of the second layer may be semi-cylindrical with a groove extending in the axial direction, and the inner layer 2 may be inserted into the groove of the outer layer 3.

[0017] The blending ratio of the industrial waste plastic of the inner layer 2, the inorganic fiber material of the outer layer 3 and the binder to the entire solid fuel is as follows: Industrial waste plastic: 5-95% by mass, Inorganic fibers: 5 to 50% by mass, Binder: 0.5 to 50% by mass

[0018] The industrial waste plastics include polyester resins containing polyethylene terephthalate such as PET bottles, polystyrene resins such as food trays, and vinyl chloride resins such as polyvinyl chloride, which are separated and collected from homes, stores, offices, etc. If the amount of industrial waste plastics is too high, a large amount of chlorine is generated during combustion, and if the amount is too low, the amount of heat generated is small, so the amount is set to 5 to 95% by mass, preferably 10 to 90% by mass.

[0019] Examples of inorganic fibers that can be used include rock wool, waste paper, sawdust, demolition waste, raw rubber, raw sludge, burnt ash, fly ash, etc. If the amount of inorganic fibers is too much, the calorific value will be low, and if the amount is too little, the strength will be low, so the amount is set to 5 to 50% by mass, preferably 5 to 20% by mass.

[0020] As the binder, vinyl acetate, lignin, molasses, sodium silicate, alpha starch, carboxymethyl cellulose, thermosetting resin, and thermoplastic resin can be used. If the binder is used in an amount that is too large, the viscosity increases, and moldability and productivity deteriorate, while if the binder is used in an amount that is too small, the viscosity decreases, the strength during molding decreases, and productivity deteriorates significantly, so the binder is used in an amount of 0.5 to 50% by mass, preferably 0.5 to 20% by mass.

[0021] <Main material for the inner layer> The raw material of the industrial waste plastic that will be the inner layer 2 is, through industrial analysis, Ash content: 5% by mass or less, Fixed carbon: 10~30% by mass, Volatile content: 50-95% by mass, Moisture: 3% by mass or less It is.

[0022] Ash content is the weight of the residue when burned under specified conditions, expressed as a percentage of the weight of the original sample, and is tested according to JIS Z 7302-4. The lower the ash content, the higher the calorific value and the less waste material remains. Calcium oxide (CaO): 0.3% by mass or less, Silicon dioxide (SiO2): 4.5% by mass or less, Aluminum oxide (Al2O3): 0.5% by mass or less It is preferable that:

[0023] Fixed carbon is calculated as the remainder when the sum of moisture, ash, and volatile matter is subtracted from 100. The lower the fixed carbon content, the better the combustibility and the less waste material is left behind, so the range was set at 10-30% by mass.

[0024] Volatile content is the ignition loss, which is the weight loss when heated under specified conditions, expressed as a percentage of the weight of the original sample. The higher the volatile content, the easier it is to burn, so it was set to 50-95% by mass.

[0025] Moisture content is the mass difference between before and after drying when heated and dried under specified conditions, expressed as a percentage by mass of the sample, and is tested according to JIS Z 7302-3. The lower the moisture content, the higher the heat generation and the easier it is to ignite, so it is set at 3% by mass or less.

[0026] The industrial waste plastics that make up the inner layer 2 are heat-melted products that are obtained by heating and melting them in a reducing atmosphere in a heat treatment furnace filled with inert gases such as argon and helium, or reducing gases such as nitrogen, carbon monoxide, and carbon dioxide. By heating in a reducing atmosphere, there is no adhesion to the mold during molding, improving work efficiency, and preventing ignition and combustion during manufacturing, thereby preventing fires.

[0027] <Outer layer secondary materials> The raw material of the outer layer 3, which is made of inorganic fibers and a binder, is determined by industrial analysis to be: Ash content: 40% by mass or less, Fixed carbon: 40~60% by mass, Volatile content: 8-10% by mass, Moisture: 3% by mass or less It is.

[0028] Ash content is the weight of the residue when burned under specified conditions, expressed as a percentage of the weight of the original sample, and is tested according to JIS Z 7302-4. The lower the ash content, the higher the calorific value and the less waste material remains. Calcium oxide (CaO): 10% by mass or less, Silicon dioxide (SiO2): 20% by mass or less, Aluminum oxide (Al2O3): 10% by mass or less It is preferable that:

[0029] Fixed carbon is calculated as the remainder when the sum of moisture, ash, and volatile matter is subtracted from 100. The higher the fixed carbon content, the better the combustibility and the less waste material is left behind, so we set it at 40-60% by mass.

[0030] Volatile content is the ignition loss, which is the weight loss when heated under specified conditions, expressed as a percentage of the weight of the original sample. The higher the volatile content, the easier it is to burn, so it was set to 8-10% by mass.

[0031] Moisture content is the mass difference between before and after drying when heated and dried under specified conditions, expressed as a percentage by mass of the sample, and is tested according to JIS Z 7302-3. The lower the moisture content, the higher the heat generation and the easier it is to ignite, so it is set at 3% by mass or less.

[0032] <Components and characteristics of solid fuel> The components of the solid fuel 1, 1a consisting of the inner layer 2 and the outer layer 3 are determined by proximate analysis as follows: Ash content: 20% by mass or less, Fixed carbon: 20~30% by mass, Volatile content: 50-70% by mass, Moisture: 1~10% by mass or less It is.

[0033] Ash content is the weight of the residue when burned under specified conditions, expressed as a percentage of the weight of the original sample, and is tested according to JIS Z 7302-4. The lower the ash content, the higher the calorific value and the less waste material remains. Calcium oxide (CaO): 5% by mass or less, Silicon dioxide (SiO2): 10% by mass or less, Aluminum oxide (Al2O3): 5% by mass or less It is preferable that:

[0034] Total chlorine content indicates the amount of chlorine in the fuel. Total chlorine content is tested according to JIS Z 7302-6. Chlorine generates toxic gases when burned, so it is set to 0.2 mass% or less.

[0035] The specific gravity is preferably 0.3 to 0.8. The solid fuels 1 and 1a of the present invention have a relatively small specific gravity compared to the conventional product (RPF), and therefore are easy to handle during transportation, conveyance, throwing, etc., and the amount used is reduced.

[0036] In the solid fuel of this embodiment, the ratio of the inner layer 2 to the inner layer 3 can be changed by adjusting the amount of the outer layer 3 of the inorganic fiber material, thereby adjusting the specific gravity and reducing the amount of chlorine contained in the industrial waste plastic in the inner layer 2. Therefore, the solid fuel of this embodiment generates less chlorine-based gas during combustion, and can use chlorine-based waste plastic as the main raw material and make effective use of it.

[0037] In the solid fuels 1 and 1a, the first layer made of industrial waste plastic is a cylindrical or semi-cylindrical inner layer 2, and the second layer made of inorganic fibers is a cylindrical or semi-cylindrical outer layer 3. However, the first layer made of industrial waste plastic may be a cylindrical or semi-cylindrical outer layer 3, and the second layer made of inorganic fibers may be a cylindrical or semi-cylindrical inner layer 2.

[0038] <Solid fuel manufacturing method> Next, a method for producing the solid fuel 1 of the embodiment will be described.

[0039] As shown in Figures 3 and 4, the manufacturing method of the solid fuel 1 of the embodiment includes a step of manufacturing the inner layer 2, a step of manufacturing the outer layer 3, a joining step of inserting and joining the inner layer 2 to the outer layer 3, a cutting step, and a drying step.

[0040] The manufacturing process of the inner layer 2 includes a fixed amount supplying step, a mixing and kneading step, and a molding step.

[0041] In the constant-volume supply process, the raw material stored in the raw material storage device 11 is continuously supplied at a constant amount by the constant-volume supply device 12. The raw material is industrial waste plastic, such as polyester resin, polystyrene resin, polyvinyl chloride resin, etc.

[0042] In the mixing and kneading process, the supplied raw materials are mixed and kneaded by the mixer 13. As the mixer 13, a ribbon-type mixer with double ribbon-shaped blades arranged horizontally, or a mortar mixer with vertical stirring blades for making mortar can be used.

[0043] In the molding process, the mixed and kneaded raw materials are molded by the extrusion device 14 equipped with a heating and melting device 15a and a cooling device 15b at the front and rear, and are continuously extruded into a cylindrical shape, i.e., a rod shape. The diameter of the molded product can be changed by changing the die of the extrusion device 14a. The extrusion device 14 is provided with a heating and melting device 15a at the inlet side of the raw materials for heating the raw materials in a reducing atmosphere, and a cooling device 15b at the outlet side for cooling the molded product with a water-cooled shower in a reducing atmosphere. The heating and melting device 15a may be provided only at the inlet side. The heating and melting device 15a is provided with openable doors 15c and 15d at the inlet side for receiving the raw materials from the mixing device 13 and the outlet side for discharging the heated raw materials, which have an internal sealed space. The cooling device 15b is also provided with doors 15e and 15f at the inlet side and the outlet side. The reducing atmosphere is created by blowing inert gases such as argon and helium, and reducing gases such as hydrogen, carbon monoxide, and carbon dioxide into the heating and melting device 15a and the cooling device 15b, heating the material to a temperature of 200 to 300°C, and maintaining the material at atmospheric pressure. By heating the material in a reducing atmosphere, there is no adhesion to the mold during molding, improving work efficiency, and preventing the material from igniting or burning, thereby preventing fires. The extrusion device 14 may be provided integrally with a device that performs the mixing and kneading process.

[0044] The manufacturing process of the outer layer 3 includes a fixed amount supplying step, a mixing and kneading step, and a molding step.

[0045] In the quantitative supply process, a constant amount of fibrous material stored in the raw material storage device 11a is continuously supplied by the quantitative supply device 12a. As the fibrous material, waste paper, sawdust, demolition waste, raw rubber, raw sludge, burnt ash, fly ash, etc. are used in appropriate combination.

[0046] In the mixing and kneading process, the supplied fibrous material and the binder contained in the binder tank 11b are mixed and kneaded by the mixer 13a. As the binder, any one of vinyl acetate, lignin, molasses, sodium silicate, alpha starch, carboxymethyl cellulose, thermosetting resin, thermoplastic resin, or a combination of these is used. As the mixer 13a, a ribbon-type mixer with double ribbon-shaped blades arranged horizontally, or a mortar mixer with vertical stirring blades for making mortar can be used.

[0047] In the molding process, the mixed and kneaded raw materials are molded by the extrusion device 14a and continuously extruded into a hollow cylindrical shape. By changing the die of the extrusion device 14, it is possible to mold into a hollow semi-cylinder shape. In addition, it is possible to mold into not only a hollow cylindrical shape or a hollow semi-cylinder shape, but also a triangular, rectangular, pentagonal, hexagonal, or other angular tube shape. The extrusion device 14a may be an integrated device that performs the mixing and kneading process.

[0048] In the joining step, the cylindrical molded product formed in the molding step of the inner layer 2 is inserted into the cylindrical molded product formed in the molding step of the outer layer 3 and joined together.

[0049] In the cutting process, the molded product extruded in the molding process is cut by cutter 16 into a predetermined length of 50 mm to 150 mm.

[0050] In the drying step, the cut molded products are dried or cooled in a drying device 17 or in the air to produce a finished solid fuel. EXAMPLES

[0051] The inner layer was 60% by mass and the outer layer was 40% by mass. For the inner layer, waste plastic, which was the main ingredient made of polyester resin, was prepared, and for the outer layer, secondary ingredients of 10% rock wool, 20% raw sludge, 67% coke powder, and 3% binder were prepared. The components of the solid fuel produced by the above-mentioned manufacturing method were as follows: Ash content: 16.72% by mass Fixed carbon: 22.78% by mass Volatile content: 57.60% by mass Moisture: 3.00% by mass Ash Breakdown: Silicon dioxide (SiO2): 9.83% by mass Aluminum oxide (Al2O3): 3.24% by mass Calcium oxide (CaO): 3.55% by mass

[0052] Table 1 shows a comparison between conventional solid fuel (RPF) and the solid fuel of the present invention. [Table 1]

[0053] The solid fuel according to the embodiment of the present invention can be effectively used in various fields. It can be used as boiler fuel for manufacturers who operate industrial boilers, as fuel for blast furnaces and electric furnaces in the iron and steel industry, as fuel for homes, camping, and public baths, and as emergency fuel for disasters. Depending on the application, the diameter and size can be adjusted and it can be supplied loose or sold in small packages.

[0054] In addition, the solid fuel of the present invention uses plastics, which are industrial waste, as a main raw material, and therefore contributes to the reuse of these industrial waste plastics, enabling stable waste treatment at the source of waste generation. Since industrial waste plastic is a waste for which there is a fee, raw material costs can be kept low and it can be produced inexpensively. It is expected that this will reduce the use of fossil fuels such as coal that have been used traditionally, and thus cut carbon dioxide emissions, thereby contributing to decarbonization. Industrial waste plastic is one of the industrial waste materials that can produce a high calorific value of 6,000 to 7,000 Kcal, so it is expected to produce electricity with high efficiency. Increasing demand for solid fuel containing the industrial waste plastic of the present invention will promote the recovery and reuse of industrial waste plastic, greatly contributing to the reduction of marine microplastics and the prevention of the destruction of ecosystems. [Explanation of symbols]

[0055] 1,1a…solid fuel 2…Inner layer 3…Outer layer 11, 11a…Raw material storage device 11b…Binder tank 12,12a…Quantitative supply device 13,13a…Mixing device 14, 14a...Extrusion device 15a…Heat melting device 15b…Cooling device 16…Cutter 17...Drying device

Claims

1. A solid fuel containing industrial waste plastic, A first layer made of a heat-melted product obtained by heating and melting industrial waste plastics under a reducing atmosphere; A second layer made of inorganic fibers and a binder; A solid fuel consisting of

2. The industrial waste plastic is 5 to 95% by mass, The inorganic fiber material is 5 to 50% by mass, The solid fuel according to claim 1, wherein the binder is contained in an amount of 0.5 to 50 mass %.

3. The solid fuel according to claim 1 , wherein the industrial waste plastics include polyester resin, polystyrene resin, and polyvinyl chloride resin.

4. The solid fuel is Ash content 20% by mass or less, Fixed carbon 20-30% by mass, Volatile content: 50 to 70% by mass; The solid fuel according to claim 1 , comprising:

5. The ash content is Calcium oxide (CaO) 5% by mass or less, Silicon dioxide (SiO ２ ) 10% by mass or less, Aluminum oxide (Al ２ O ３ ) 5% by mass or less The solid fuel according to claim 8 , comprising:

6. 2. The solid fuel according to claim 1, having a chlorine content of 0.2 mass % or less.

7. 2. The solid fuel according to claim 1, having a specific gravity of 0.3 to 0.

8.

8. One of the first layer or the second layer is cylindrical, and the other layer is hollow cylindrical and has an interior extending in an axial direction; The cylindrical one layer is inserted inside the other layer. The solid fuel according to claim 1.

9. One of the first layer and the second layer has a semi-cylindrical shape, and the other layer has a semi-cylindrical shape and has a groove portion extending in the axial direction, The one layer having a semi-split cylindrical shape is inserted into the groove of the other layer. The solid fuel according to claim 1.

10. A first layer forming step of forming a first layer from a main raw material consisting of industrial waste plastic; a second layer forming step of forming a second layer from a secondary raw material made of inorganic fiber material; a bonding step of bonding the first layer and the second layer to form a laminate; A method for producing solid fuel comprising the steps of:

11. The method for producing a solid fuel according to claim 10, further comprising a drying step of drying the laminate.

12. The first layer forming step includes: A quantitative supplying process for supplying a quantitative amount of a main raw material consisting of industrial waste plastic; a mixing and kneading process in which the main raw materials are mixed and kneaded while being heated and melted in a reducing atmosphere; A molding process of extruding the kneaded main raw material into a predetermined shape; The method for producing a solid fuel according to claim 10, comprising:

13. The second layer forming step includes: a quantitative supplying step of supplying a quantitative amount of an auxiliary material made of inorganic fiber material; A mixing and kneading process in which the auxiliary materials and the binder are mixed and kneaded; A molding process of extruding the kneaded auxiliary material into a predetermined shape; The method for producing a solid fuel according to claim 10, comprising:

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