Method for producing coke and resin molded article for producing coke

Abstract

To provide a technique capable of suppressing the lowering of coke strength in blending synthetic resins.SOLUTION: In the method for producing coke by charging a resin molded product and one coal into a coke oven, the resin molded product contains synthetic resins and the other coal, and the hydrogen content of the other coal is made higher than that of the one coal. The resin molded product is used for producing coke by mixing with one coal and charging into a coke oven, wherein the resin molded product contains a synthetic resin and another coal, and the hydrogen content of the other coal is higher than the hydrogen content of the one coal.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing coke, in which synthetic resins, typically waste plastics, are recycled as raw materials for iron making in a coke oven, and to a resin molded product for coke production. In the following description, the unit of mass, "t," is 10 3 In this specification, "synthetic resins" includes not only used plastics that are general waste, commonly known as waste plastics, but also plastics that become industrial waste, such as scraps and defective synthetic resins generated in the manufacturing process, and used plastics. [Background technology]

[0002] In recent years, steelworks have begun to use carbon sources other than coal, such as LNG, as fuel and reducing agents due to societal demands for reducing carbon dioxide emissions and rising coking coal prices. However, to further reduce carbon dioxide emissions, there is a need to reduce dependence on fossil fuels such as LNG. Against this backdrop, efforts are being made to recycle waste plastics as a carbon source. Traditionally, much of the waste plastic has been incinerated, but this process has a significant environmental impact, including the generation of carbon dioxide, and also poses the problem of thermal damage to the incinerator. Recycling waste plastics as a carbon source for steelworks could solve these problems. One chemical recycling technology for waste plastics involves mixing the waste plastics with coal in the steelworks' coke ovens and dry-distilling them together.

[0003] When waste plastics are mixed with coal and dry-distilled in a coke oven, the plastics tend to extract hydrogen from the coal at the contact surface during the dry-distillation process. This hydrogen extraction reduces the melting point of the coal, resulting in a decrease in the strength of the coke after dry-distillation.

[0004] Patent Document 1 discloses a technology in which plastic is heated to 180-260°C and compression molded (extrusion molded), then cut and cooled (quenched) in a water cooling device to produce a plastic molded body, which is then mixed with coal and supplied to a coke oven. This prevents a decrease in coke strength and prevents a deterioration in coke productivity. Patent Document 2 also discloses a technology in which plastic is extrusion molded while heated to a temperature above 140°C and below 180°C, and the resulting plastic molded body is cooled to 40°C or less at room temperature, and the volume of the plastic molded body is reduced to 200 cm. 3 The above-mentioned technology has been disclosed. By doing so, it is said that it is possible to suppress a decrease in coke strength even when mixed with coal and used in coke production. Furthermore, Patent Document 3 discloses a technology in which coal with a maximum particle size of 10 mm or less and an average particle size of 1 to 3 mm is mixed when molding plastic. By doing so, a method is shown in which a high-density molded waste plastic product is produced and a decrease in coke strength is suppressed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-327189 [Patent Document 2] Japanese Patent Publication No. 2023-007040 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-260871 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the methods of Patent Documents 1 to 3 have the following problems. The method of Patent Document 1 is a method for improving coke strength by producing high-density, less powdered plastic granules and using them in coke production. However, the method of Patent Document 1 does not have the effect of suppressing hydrogen abstraction, and when the granules are charged into a coke oven and used in coke production, a decrease in coke strength due to hydrogen abstraction is unavoidable, and sufficient coke strength cannot be obtained.

[0007] In addition, the method of Patent Document 2 involves heating plastic to a temperature higher than 140°C but lower than 180°C, compression molding it, and cooling it to room temperature, while reducing the volume of the plastic molded body to 200 cm3. 3 The above is the purpose. This makes it possible to increase the apparent density of the plastic molded body. Therefore, if coke is produced using the plastic molded body of Patent Document 2, hydrogen abstraction from the coke coal can be suppressed, thereby suppressing a decrease in coke strength. However, in recent years, there has been a demand for coke with even higher strength, and a method is needed that can further suppress hydrogen abstraction and prevent a decrease in coke strength.

[0008] Furthermore, the method of Patent Document 3 involves mixing and molding plastic and coal. This structure does not prevent hydrogen extraction from the coal for coke, and therefore does not prevent a decrease in coke strength.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coke production technology that can suppress a decrease in coke strength when synthetic resins are blended. [Means for solving the problem]

[0010] The coke production method of the present invention, which advantageously solves the above-mentioned problems, is a coke production method in which a resin molded body and a certain coal are charged into a coke oven to produce coke, characterized in that the resin molded body contains synthetic resins and other coal, and the hydrogen content of the other coal is made higher than the hydrogen content of the certain coal.

[0011] The coke production method according to the present invention includes the steps of: (a) making the hydrogen content of the other coal 5% by mass or more on a dry and ash-free basis; (b) the resin molding has the other coal attached to the surface of a compressed body made from the synthetic resins; (c) using at least one of a stirrer and a kneader, attaching the other coal to the surface of a compressed body produced from the synthetic resins to produce the resin molded body; This may be a more preferable solution.

[0012] The resin molded body for coke production of the present invention, which advantageously solves the above-mentioned problems, is a resin molded body used to produce coke by mixing with a certain coal and charging it into a coke oven, characterized in that the resin molded body contains synthetic resins and another coal, and the hydrogen content of the other coal is higher than the hydrogen content of the certain coal.

[0013] The resin molded product for coke production according to the present invention is (d) the resin molding has the other coals attached to the surface of a compressed body made from the synthetic resins; (e) the hydrogen content of the other coal is 5% by mass or more on a dry and ash-free basis; This may be a more preferable solution. [Effects of the Invention]

[0014] In the present invention, coke is produced by charging a resin molded body containing a second coal having a higher hydrogen content than a first coal into a coke oven together with the first coal. This makes it possible to produce high-strength coke even when using a plastic molded body. DETAILED DESCRIPTION OF THE INVENTION

[0015] The following is a detailed description of embodiments of the present invention. The following embodiments are intended to exemplify equipment and methods for embodying the technical concept of the present invention, and are not intended to limit the configuration to those described below. In other words, the technical concept of the present invention can be modified in various ways within the technical scope defined in the claims.

[0016] (Coke manufacturing method) In this embodiment, coke is produced by charging a resin molded body and ordinary coal for coke production into a coke oven. The resin molded body contains synthetic resins and coal for resin molded body production. In this embodiment, the hydrogen content of the coal for resin molded body production is made higher than the hydrogen content of ordinary coal for coke production. It is preferable that the hydrogen content of ordinary coal for coke production is less than 5 mass% on an anhydrous and ash-free basis.

[0017] (synthetic resins) In this embodiment, the synthetic resins, which are one of the raw materials for the resin molded body, are primarily thermoplastic resins. That is, the synthetic resins contain 50% by mass or more of thermoplastic resin. Preferably, the synthetic resins contain 80% by mass or more of thermoplastic resin. The synthetic resins include waste plastics, which may be subjected to pre-processing such as crushing, air sorting, or magnetic sorting as necessary. Examples of thermoplastic resins include polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride, and the raw material is a synthetic resin primarily composed of a thermoplastic resin containing one or more of these. There is no problem even if a small amount of thermosetting resin is contained.

[0018] (Coal for manufacturing resin moldings) In this embodiment, the coal for producing resin compacts is mixed into the resin compacts as one of the raw materials for the resin compacts, or is adhered to the surface of a compressed body of synthetic resins. The coal for producing resin compacts may be mixed into the resin compacts and also adhered to the surface of the compressed body. By having the coal for producing resin compacts at least on the surface of the resin compacts, the effect of reducing the hydrogen abstraction effect of the synthetic resins, described below, can be more effectively exerted. In this embodiment, the hydrogen content of the coal for producing resin compacts is made higher than the hydrogen content of the coal for ordinary coke production. By doing so, when the synthetic resins abstract hydrogen during the carbonization process in producing coke, they abstract it from the coal for producing resin compacts, which contains a large amount of hydrogen, rather than from the coal for ordinary coke production. As a result, hydrogen abstraction from the coal for coke production around the resin compacts can be suppressed, and a decrease in coke strength can be suppressed.

[0019] The hydrogen content of the coal for producing resin compacts is preferably 5% by mass or more on a dry and ash-free basis. Dry and ash-free basis refers to the coal excluding moisture and ash, which is an inorganic component. An example of coal with a hydrogen content of 5% by mass or more on a dry and ash-free basis is lignite. In particular, by increasing the hydrogen content of the coal for producing resin compacts present on the surface of the resin compact to 5% by mass or more, the hydrogen abstraction suppression effect can be further enhanced, and a decrease in coke strength can be further suppressed. High-quality, relatively expensive coals such as semi-anthracite and bituminous coal are typically used for coke production. On the other hand, relatively inexpensive sub-lignite and lignite can be used for producing resin compacts.

[0020] The blending ratio of the coal for producing resin compacts to the resin compacts is preferably in the range of 1 to 10 mass %, since this allows the surface of the compressed synthetic resin to be sufficiently covered. Note that the coal for producing resin compacts is preferably selected from coals that do not cause any harm to the production of coke, taking into consideration the amount of addition.

[0021] (Method of manufacturing resin molded body) The resin molded body is produced by molding, for example, a compressed body of synthetic resins using a twin-screw extrusion molding machine. The synthetic resins are crushed or pre-granulated before supply. In this case, it is preferable to adjust the moisture content of the synthetic resins to 5% by mass or less. By reducing the moisture content of the synthetic resins, the synthetic resins can be molded stably, and the density of the molded product increases. Various types of dryers, including hot air flow dryers, can be used to evaporate the moisture from the synthetic resins.

[0022] Any twin-screw extruder suitable for use in this embodiment and capable of molding synthetic resins may be used, and there is no difference in basic structure. The feedstock is kneaded by twin screws housed in a casing, and the synthetic resin is extruded through a nozzle attached to a heated plate. The cylindrically extruded synthetic resin is cut by a rotary cutter to a fixed length. The volume per resin molded body is adjusted by the nozzle inner diameter and the cutter cutting speed. Nozzles with an inner diameter of 20 to 30 mm are typically used. Large-diameter nozzles with an inner diameter of 40 to 60 mm are used for molding, making it possible to produce large molded products. The mass of resin molded bodies per unit increases, allowing for a greater amount to be charged for the same number of units.

[0023] The resin compacts are cylindrical with a diameter equal to or slightly larger than the inner diameter of the nozzle, and their length can be adjusted by the rotation speed of the cutter. The length of the resin compacts is affected by the position and condition of the forming nozzle, making it difficult to make them uniform in length. There is a distribution of compacts ranging from short to long. The volume can be increased by increasing the maximum length of the compacts, but it is preferable that the maximum length within the distribution of compact lengths be 200 mm or less. This is because the diameter of the charging port at the top of the carbonization chamber of a coke oven is approximately 400 to 500 mm, and if the maximum length is made longer than this, clogging may occur. The average volume of the compacts is 90 cm 3 More than 150cm is preferable. 3 More than 200cm is preferable. 3The upper limit depends on the size of the charging port when charging into the coke oven, but is 1000 cm 3 It is preferable that the distance is less than 600 cm 3 It is preferable that the resin molded body be molded so that the smaller of the diameter equivalent to a sphere, or the axial length and circular cross-sectional diameter equivalent to a cylinder, is 34 mm or more.

[0024] The resin molded body according to this embodiment can be manufactured by mixing synthetic resins and coal for manufacturing resin molded bodies in advance using a mixer or the like, and then molding the mixture.

[0025] On the other hand, first, synthetic resins are molded to produce a compact. Then, the compact and coal for producing resin compacts are mixed using at least one of a stirrer and a kneader before being charged into a coke oven, thereby producing the resin compact according to this embodiment. A normal stirrer or kneader can be used as the mixing equipment. Specifically, a mixer or a kiln may be used. A coal conditioning facility (CMC), which is a coke drying facility, may also be used.

[0026] The hydrogen abstraction suppression effect can also be seen in resin compacts made by mixing coal for resin compact production with synthetic resins and then molding them. If only the synthetic resins are molded first to produce a compressed body, and then the coal for resin compact production is attached to the surface of that compressed body, the effect of suppressing hydrogen abstraction from the surrounding coal for coke production is further enhanced.

[0027] We believe that coating the surface of the resin molded body with coal for producing resin molded bodies reduces the contact area between the coal for cokemaking and synthetic resins, thereby contributing to suppressing a decrease in coke strength. Hydrogen abstraction from the coal for cokemaking by synthetic resins occurs on the surface of the resin molded body where the coal for cokemaking and synthetic resins come into contact. Therefore, by having coal for producing resin molded bodies present on the surface of the resin molded body, hydrogen abstraction from the coal for cokemaking can be more effectively suppressed.

[0028] Furthermore, by setting the hydrogen content of the coal for producing resin molded bodies, particularly the coal for producing resin molded bodies that is present on the surface of the resin molded bodies, to 5 mass% or more on an anhydrous and ashless basis, it is possible to further suppress hydrogen abstraction from the coal for producing coke.

[0029] (Method of charging raw materials into a coke oven) In this embodiment, when coal (raw coal) and resin compacts are supplied as coke raw materials into the carbonization chamber of a coke oven, the coal and resin compacts are transported together to the top of the coal tower. In this embodiment, the coal and resin compacts stored in the coal tower are supplied to coal transport cars. The coke raw materials are then charged into the furnace of the carbonization chamber from the coal transport cars through multiple charging ports at the top of the carbonization chamber. The coke raw materials are then carbonized in the carbonization chamber to produce coke.

[0030] As an index of coke strength, the drum strength index DI (150 / 15) can be measured according to the drum strength measurement method specified in JIS K2151:2004, a coke is charged into a drum testing machine, rotated 150 times, and then sieved through a 15 mm mesh sieve. [Example]

[0031] The effects of the present invention will be specifically described below with reference to examples. Note that the following examples are merely illustrative and do not limit the technical scope of the present invention.

[0032] (Example 1) Coke was produced as follows. Bituminous coal with a hydrogen content of 3% by mass on an anhydrous and ashless basis was used for the coal used to produce coke. Used plastics were used for the synthetic resins. The synthetic resins were molded to produce a compact. Lignite with a hydrogen content of 6% by mass on an anhydrous and ashless basis was used for the coal used to produce the resin compacts, which were attached to the surface of the compact. Water was added to the compact and the coal used to produce the resin compacts so that the moisture content was 10% by mass relative to the total mass of the synthetic resins, and then the mixture was placed in a mixer. The mixture was thoroughly mixed in the mixer, and the coal used to produce the resin compacts was attached to the surface of the compact to produce a resin compact. The amount of coal used to produce the resin compacts attached was 10% by mass relative to the total mass of the synthetic resins. The mixing ratio of the resin compacts to the coal used to produce coke was 2% by mass relative to the mass of the coal used to produce coke. The coal used to produce coke and the resin compacts were mixed and charged into a coke oven for carbonization to produce coke. The coke strength DI (150 / 15) of the product coke was 83.0.

[0033] (Example 2) Except for the fact that the coal for producing resin compacts was mixed with synthetic resins in advance and molded, coke was produced in the same manner as in Invention Example 1. The coke strength DI (150 / 15) of the product coke was 82.4.

[0034] (Comparative Example 1) Except for the fact that the resin compacts were produced using only synthetic resins without using coal for producing resin compacts, coke was produced in the same manner as in Invention Example 1. The coke strength DI (150 / 15) of the product coke was 82.0.

[0035] (Comparative Example 2) Except for using bituminous coal for coke production, which had a hydrogen content of 3 mass% on an anhydrous ash-free basis, as the coal for producing resin compacts, coke was produced in the same manner as in Example 1. The coke strength DI (150 / 15) of the product coke was 82.2.

[0036] The above results demonstrate that Examples 1 and 2, in which coal for producing resin compacts with a higher hydrogen content than coal for coke production was used in the resin compact, had superior coke strength to Comparative Examples 1 and 2. In particular, Example 1, in which coal with a high hydrogen-oil content was placed on the surface of the resin compact, had superior coke strength to Example 2, in which coal was placed over the entire resin compact. [Industrial Applicability]

[0037] Although the above description has been made on synthetic resins, the present invention is not limited to this. The same effect can be obtained when biomass is mixed with synthetic resins or when biomass is substituted for synthetic resins.

Claims

1. A coke production method for producing coke by charging a resin molded body and one coal into a coke oven, comprising: The resin molded body contains synthetic resins and other coals, a hydrogen content of the other coal being higher than a hydrogen content of the one coal;

2. The method for producing coke according to claim 1 , wherein the hydrogen content of the other coal is 5 mass% or more on an anhydrous ash-free basis.

3. 3. The method for producing coke according to claim 1, wherein the resin molded body is a compressed body made from the synthetic resins, and the other coal is adhered to the surface of the compressed body.

4. 4. The coke production method according to claim 3, wherein the resin molded body is produced by adhering the other coal to the surface of a compressed body produced from the synthetic resins using at least one of a stirrer and a kneader.

5. A resin molded body to be mixed with one coal and charged into a coke oven to produce coke, The resin molded body contains synthetic resins and other coals, The resin molded body for coke production, wherein the hydrogen content of the other coal is higher than the hydrogen content of the one coal.

6. The resin molded body for coke production according to claim 5 , wherein the resin molded body is a compressed body made from the synthetic resins, and the other coals are attached to the surface of the compressed body.

7. The resin molded product for coke production according to claim 5 or 6, wherein the other coal has a hydrogen content of 5 mass% or more on an anhydrous and ashless basis.