JP2011068770A - Solid fuel and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid fuel having sufficient flammability and capable of sufficiently reducing fusion to a heater. <P>SOLUTION: The solid fuel is manufactured by a powder obtained from coal and petroleum coke and a heat treatment article obtained by heating a plastic. The powder contains at least either one of a fine powdery coal obtained by pulverizing the coal and a thermal decomposition article of the fine powdery coal, and at least either one of a petroleum coke powder obtained by pulverizing the petroleum coke and a thermal decomposition article of the petroleum coke powder, and the plastic contains a thermoplastic resin. The heat treatment article contains a re-solidified article obtained by cooling the thermoplastic resin after it is melted. The content of a volatile article of the solid fuel is 10-80 mass%, the content of fixed carbon is 10-80 mass%, and the moisture content is 0-50 mass%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solid fuel and a method for producing the same.

  In order to make effective use of waste, it has been studied to use waste plastic contained in municipal waste and industrial waste as solid fuel. Usually, such a solid fuel is produced by heat-processing waste plastic with coal in a heating furnace (for example, refer to Patent Documents 1 and 2).

  From the viewpoint of effective use of waste, it is required to produce solid fuel by increasing the use ratio of waste plastic as much as possible. On the other hand, since such a solid fuel is used as a fuel, it is naturally required to have excellent combustibility.

  In response to such demands, it has been proposed to produce waste fuel (coke) for a blast furnace by mixing waste plastic and coal and subjecting them to dry distillation in a coke oven (see, for example, Patent Document 1).

  Further, in the production of solid fuel using waste plastic, since the waste plastic is used as a raw material, it tends to be fused to the furnace wall of the heating furnace or the obtained solid fuel is agglomerated. In order to improve such a point, it has been proposed to produce a solid fuel by adding dust obtained by burning organic substances to a raw material together with waste plastic as an anti-fusing material (for example, Patent Document 2). reference).

  In addition, it has been proposed to modify low-grade coal by adding a thermoplastic resin to heated pulverized coal and coating the periphery of the pulverized coal with a thermoplastic resin (see, for example, Patent Document 3).

Japanese Patent No. 399596 JP 2008-106270 A JP-A-6-108073

  Since the manufacturing method of the solid fuel using waste plastic is normally performed on an industrial scale, it is required to manufacture the solid fuel in a high yield and a simple process. Further, the produced solid fuel is required to have good combustibility. However, in the method of Patent Document 1 described above, when the solid fuel (coke) is produced, the raw material containing the plastic is heated to a high temperature (1000 ° C. or more) and dry-distilled. And the yield of the obtained solid fuel will become low. In addition, such solid fuels are not sufficiently ignitable due to low volatile content.

  Further, in the method of Patent Document 2, since it is necessary to prepare an anti-fusing material separately, the process becomes complicated, and dust or partial combustion slag obtained by combustion is used as the anti-fusing material. Therefore, there is room for improvement in the combustibility of the obtained solid fuel. Moreover, in the method of patent document 3, since the molten thermoplastic resin adheres to the surface of pulverized coal, there is a concern that the molten thermoplastic resin adheres to the inside of the heating apparatus. In particular, when a large amount of pulverized coal is granulated on an industrial scale, adhesion to the inside of the apparatus can be a problem.

  The present invention has been made in view of the above circumstances, and even if a thermoplastic is used as a raw material, it is possible to suppress fusion to the inside of the heating device, and a solid fuel having good combustibility is obtained. It is an object of the present invention to provide a method for producing a solid fuel that can be easily produced with a high yield. It is another object of the present invention to provide a solid fuel that has good combustibility and can sufficiently reduce fusion to a heating device.

  In order to achieve the above object, in the present invention, a solid fuel containing a powder obtained from coal and petroleum coke and a heat-treated product obtained by heating a plastic, the powder pulverized coal. At least one of pulverized coal and a pyrolyzed product of the pulverized coal, and at least one of petroleum coke powder obtained by pulverizing petroleum coke and the pyrolyzed product of the petroleum coke powder, and the plastic contains a thermoplastic plastic. The heat-treated product contains a re-solidified product obtained by cooling after melting the thermoplastic plastic, the volatile content is 10 to 80% by mass, the fixed carbon content is 10 to 80% by mass, And a solid fuel having a water content of 0 to 50% by mass.

  Since the solid fuel of the present invention contains the above powder together with the heat-treated product of plastic, even if it contains a thermoplastic that easily adheres to the inside of the heating device, the thermoplastic melts inside the heating device. Adherence of objects can be sufficiently reduced. Moreover, since it contains volatile matter, fixed carbon, and moisture in a specific range, it has good combustibility.

  The solid fuel of the present invention preferably has a first phase containing the re-solidified product as a main component and a second phase containing the powder as a main component and covering the outer periphery of the first phase. . By having such a phase structure, the phase of pulverized coal, petroleum coke powder or their pyrolyzate is interposed between the phases of the plastic re-solidified product, and the re-solidified product is melted by heating. In addition, it is possible to sufficiently suppress fusion in the apparatus. Moreover, since it has the 2nd phase so that the 1st phase with comparatively quick combustion may be covered, it becomes possible to maintain combustion over a long time.

  The solid fuel of the present invention has a C (carbon) content of 70 to 90% by mass, a H (hydrogen) content of 1 to 20% by mass, and O (oxygen) as measured in accordance with JIS M 8819. It is preferable that the content rate of is 0-30 mass%. By containing each element in such a range, it can be set as the solid fuel which has further favorable combustibility. Such a solid fuel is particularly suitable as a fuel for burning cement.

  The solid fuel of the present invention has a weight loss rate at 350 ° C. (an anhydrous ashless basis) in a thermogravimetric analysis in which the temperature is increased in air at a rate of temperature increase of 10 ° C./min. ) Is 1 to 70%, and the weight loss rate at 500 ° C. (an anhydrous ashless basis) is preferably 15 to 100%. Thereby, it can be set as the solid fuel which has much better combustibility.

  The solid fuel of the present invention preferably has an HGI of 15-40. Such a solid fuel having HGI can be easily pulverized and has both good handleability and good combustibility.

  The solid fuel of the present invention is granular, and it is preferable that 50% by mass or more of the particles have a particle diameter of 1.0 mm or more and less than 30 mm. A granular solid fuel having such a particle size has both good handleability and good combustibility.

  The solid fuel of the present invention preferably has a high calorific value (air-dry basis) of 20,000 to 40,000 kJ / kg. As a result, a calorific value substantially equal to that of coal can be obtained.

  The solid fuel of the present invention is mixed with 50 to 500 parts by mass of pulverized coal and petroleum coke powder with respect to 100 parts by mass of thermoplastic plastic, and melts after melting at least a part of the thermoplastic plastic. The thermoplastic resin is preferably obtained by cooling and re-solidifying and granulating. As a result, it is possible to obtain a solid fuel having good handleability and good combustibility while effectively utilizing waste.

  In the solid fuel of the present invention, the plastic preferably contains waste plastic. As a result, it is possible to produce a solid fuel at low cost while effectively using waste.

  The solid fuel of the present invention preferably has an average particle size of the above powder of 500 μm or less. Thus, by including fine pulverized coal and / or pyrolyzate, it is possible to obtain a solid fuel in which fusion in the apparatus is further suppressed.

  In another aspect of the present invention, a plastic containing a thermoplastic plastic, and a powder containing a pulverized coal obtained by pulverizing coal and a petroleum coke powder obtained by pulverizing petroleum coke, 100 masses of plastic. A charging step of charging the powder into the heating device at a ratio of 50 to 500 parts by mass, a mixing step of mixing the plastic and the powder to obtain a mixture, and heating the mixture to thermoplastic A solidified product comprising a resolidified product obtained by solidifying the melted product after obtaining a molten product, and a heating step for obtaining a solid fuel containing at least one of the powder and the pyrolyzed product of the powder. A method for producing a fuel is provided.

  Since the solid fuel obtained by the production method of the present invention is a solid fuel produced by mixing plastic, pulverized coal and petroleum coke powder at a predetermined ratio, even if the thermoplastic melts in the heating step, The pulverized coal and petroleum coke powder adhere to the surface of the thermoplastic melt, and the fusion of the thermoplastic melt into the apparatus can be sufficiently suppressed. Moreover, since the solid fuel produced contains a re-solidified product of thermoplastic, pulverized coal or a decomposed product thereof, and petroleum coke powder or a decomposed product thereof, it has good combustibility.

  In the production method of the present invention, the volatile content of the solid fuel is preferably 30 to 80% by mass in the heating step. Moreover, it is preferable that the yield of the solid fuel with respect to the mixture in a heating process is 70% or more on a mass basis. As a result, the volatilization of the raw material thermoplastic, pulverized coal, and petroleum coke powder is suppressed, the content of volatile matter in the solid fuel is increased, and a solid fuel having better combustibility can be produced.

  In the production method of the present invention, the average particle size of the powder is preferably 500 μm or less. Thereby, the fusion | fusion in a heating apparatus can be suppressed further.

  In the production method of the present invention, it is preferable to perform at least a part of the heating step under a negative pressure. As a result, the partial pressure of the tar component generated by the thermal decomposition of the plastic is lowered, the fusing property of the surface of the plastic melt is reduced, and the integration and agglomeration of the solids can be further reduced. By such an action, a granular solid fuel having a smaller particle diameter can be obtained.

  In the production method of the present invention, the heating step is preferably performed in an atmosphere having an oxygen gas concentration of 18% by volume or less. By performing thermal decomposition in such an atmosphere, the progress of oxidation is suppressed, and a solid fuel can be obtained with a higher yield.

  According to the present invention, even when a thermoplastic is used as a raw material, it is possible to suppress fusion to the inside of the heating device, and to easily produce a solid fuel having good combustibility in a high yield. It is possible to provide a method for producing a solid fuel capable of satisfying the requirements. Moreover, the solid fuel which has favorable combustibility and can fully reduce the fusion | melting to a heating apparatus can be provided.

It is process drawing of the manufacturing method of the solid fuel which is one suitable embodiment of this invention. It is a block diagram of the heating apparatus used for the manufacturing method of the solid fuel which is one suitable embodiment of this invention. It is a scanning electron microscope (SEM) photograph (magnification: 150 times) which shows the section structure of the solid fuel of this embodiment. It is a schematic diagram which shows the example of the stirring plate inside the rotary kiln type | mold heating furnace suitably used for the manufacturing method of the solid fuel which is preferable one Embodiment of this invention. It is a graph which shows the particle size distribution (volume basis) of the organic substance powder obtained by mixing the petroleum coke powder and pulverized coal which were used as a raw material in Example 1 of this invention by the mass ratio of 35:65. It is a graph which shows the thermogravimetric analysis (TG) result of the petroleum coke powder single-piece | unit used as a raw material in Example 1 of this invention. It is a graph which shows the thermogravimetric analysis (TG) result of the pulverized coal single-piece | unit used as a raw material in Example 1 of this invention. It is a graph which shows the thermogravimetric analysis (TG) result of the mixture (pulverized coal: petroleum coke = 65: 35, mass ratio) of the pulverized coal which is the raw material of Example 1 of this invention, and petroleum coke powder. It is a graph which shows the thermogravimetric analysis (TG) result of the solid fuel of Example 1 of this invention.

  In the following, preferred embodiments of the present invention will be described with reference to the drawings as the case may be. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  The solid fuel of this embodiment is a solid fuel containing powder obtained from coal and petroleum coke and a heat-treated product obtained by heating plastic. The powder is obtained by pyrolyzing petroleum coke powder and / or petroleum coke powder obtained by pulverizing petroleum coke together with pulverized coal obtained by pulverizing coal and / or a pyrolyzate obtained by pyrolyzing the pulverized coal. Containing thermal decomposition products. The heat-treated product of plastic contains a re-solidified product obtained by melting the thermoplastic and then cooling it. The solid fuel of the present embodiment has a volatile content of 10 to 80% by mass, a fixed carbon content of 10 to 80% by mass, and a moisture content of 0 to 50% by mass. In the present specification, pulverized coal, pyrolyzed product of pulverized coal, petroleum coke powder, and pyrolyzed product of petroleum coke powder may be collectively referred to as “thermally decomposed product”.

  The volatile content of the solid fuel of the present embodiment is preferably 45 to 65% by mass, and more preferably 50 to 60% by mass. When the content of volatile matter in the solid fuel is less than 45% by mass, the yield of the obtained solid fuel becomes low, and the ignitability tends to deteriorate and good combustibility tends to be impaired.

  By the way, when the plastic which is the raw material of the solid fuel is heated, only the flammable volatile matter is volatilized from the thermoplastic plastic which does not contain chlorine such as polyethylene. On the other hand, chlorine evaporates from plastics containing chlorine, such as vinyl chloride, together with combustible volatile components (desalting). Therefore, when the content of volatile matter in the solid fuel exceeds 65% by mass, there is no problem since the yield of volatile matter is only increased if the plastic used as the raw material is a thermoplastic plastic that does not contain chlorine. When a plastic containing chlorine is contained in the raw material, the desalting becomes insufficient as the volatile content in the solid fuel increases, and impurity components such as chlorine in the solid fuel increase. Therefore, when chlorine is contained in the thermoplastic thermoplastic material, the volatile content of the solid fuel is preferably 65% or less.

  The fixed carbon content of the solid fuel of the present embodiment is preferably 30 to 45% by mass, and more preferably 30 to 42% by mass. By containing fixed carbon in such a range, it is possible to maintain good combustion over a longer period than solid fuels made of waste plastic. Note that when the solid carbon content of the solid fuel is less than 30% by mass, it tends to be difficult to form an excellent high temperature field. On the other hand, when the solid carbon content of the solid fuel exceeds 45% by mass, excellent ignitability tends to be impaired.

  The moisture content of the solid fuel of the present embodiment is preferably 0 to 30% by mass, more preferably 1 to 20% by mass, and further preferably 1 to 10% by mass. Even when high moisture coal is used as a raw material, it is possible to obtain a solid fuel with reduced fusion and excellent combustibility.

  The ratio of fixed carbon to volatile matter (fuel ratio) is preferably 0.5 to 0.8, and more preferably 0.6 to 0.8. A solid fuel having a fuel ratio in such a range has more excellent combustibility.

  The lower limit of the higher calorific value (air-dried basis) of the solid fuel of the present embodiment is preferably 20,000 kJ / kg, more preferably 28,000 kJ / kg, and further preferably 29,000 kJ / kg. . If the higher calorific value of the solid fuel becomes too low, sufficiently good combustibility tends to be impaired. On the other hand, the upper limit of the higher heating value of the solid fuel is substantially 40,000 kJ / kg.

  In the present specification, the higher heating value refers to an air-drying heating value per unit weight (1 kg) measured in accordance with JIS M-8814. Moreover, the content rate of a volatile matter, fixed carbon, and a water | moisture content says the content rate of an air-dry base measured based on JISM-8812.

The average specific surface area of the solid fuel of the present embodiment is preferably 1 m ² / g or less, more preferably 0.4 m ² / g or less, and further preferably 0.3 m ² / g or less. By having such a small average specific surface area, for example, generation of dust explosion can be sufficiently suppressed as compared with coal (pulverized coal) pulverized under the same pulverization conditions. Although no particular limitation to the lower limit of the average specific surface area, from the viewpoint of easy production of the solid fuel, the average specific surface area is preferably 0.05 m 2 / ^g or more, more preferably 0.1 m 2 / ^g or more is there.

When the solid fuel of this embodiment is pulverized, it is considered that the specific surface area is smaller than that of coal and petroleum coke pulverized under the same pulverization conditions. That is, the average specific surface area of particles obtained by pulverizing coal and petroleum coke is A, and the average specific surface area of solid fuel particles obtained by pulverizing solid fuel under the same pulverization conditions as coal and petroleum coke is B. Then, it is considered that the following relationship is established.
Average specific surface area of solid fuel particles B ≦ Average specific surface area of coal and petroleum coke particles A
It is expected to be.
Here, the same pulverization conditions refer to conditions for pulverization until the average particle diameter after pulverization becomes the same.

  Low-grade coal is not carbonized and has many fine voids. Petroleum coke also has many micropores. Therefore, although the specific surface area at the time of pulverization is large, the specific surface area is reduced by covering the voids and micropores with the molten thermoplastic, and the occurrence of dust explosion is sufficiently suppressed compared to coal and petroleum coke under the same pulverization conditions. Can do. In addition, the above-mentioned average specific surface area can be measured using ASAP2420 (device name) manufactured by Shimadzu Corporation based on JIS Z-8830.

  The solid fuel of the present embodiment preferably has a C (carbon) content of 70 to 90% by mass, more preferably 70 to 80% by mass, even more preferably 75 to 80% by mass; and a content of H (hydrogen). Preferably it is 1-20 mass%, More preferably, it is 3-8 mass%; The content rate of O (oxygen) is preferably 0-30 mass%, More preferably, it is 1-15 mass%, More preferably, it is 2-10 mass% The content of N (nitrogen) is preferably 0 to 2% by mass, more preferably 0.5 to 1% by mass; the content of Cl (chlorine) is preferably 1.5% by mass or less, more preferably 1. 0% by mass or less. In addition, the content rate of each above-mentioned element is a value (anhydrous base) measured based on JIS M-8819.

  In the solid fuel of this embodiment, the weight reduction rate when the temperature is increased to 350 ° C. in the thermogravimetric analysis in which the temperature is increased at a temperature increase rate of 10 ° C./min in an air stream is based on the weight before the start of the temperature increase. Is preferably 1 to 70% by weight, more preferably 5 to 50% by weight, and still more preferably 15 to 40% by weight. Further, in the same thermogravimetric analysis, the weight reduction rate when the temperature is increased to 500 ° C. is preferably 15 to 100% by weight, more preferably 60 to 100% by weight, based on the weight before the start of temperature increase. Preferably it is 80 to 100 weight%. The solid fuel having such a weight reduction rate can achieve both excellent ignitability and formation of a high temperature field at a high level. In addition, the above-mentioned weight loss amount is a value on an anhydrous ashless basis that is measured using a normal thermogravimetric analyzer in an air atmosphere.

  The HGI of the solid fuel of the present embodiment is preferably 15 to 40, and more preferably 20 to 35. Such a solid fuel having HGI has the advantage that it can be easily pulverized, the particle size can be easily adjusted, and the usage is expanded. In addition, HGI (hard glove index, coal grindability index) can be measured using a commercially available measuring device in accordance with JIS M-8801.

  The average particle size (before pulverization) of the solid fuel of the present embodiment is preferably 2 to 15 mm, more preferably 5 to 10 mm. A solid fuel having such an average particle size before pulverization is excellent in handleability and combustibility. If the average particle size (before pulverization) of the solid fuel becomes too large, the solid fuel tends to be easily clogged at the outlet of the heating furnace for producing the solid fuel or the inlet of the facility using the solid fuel. In addition, the average particle diameter in this specification means a particle diameter (median diameter) corresponding to 50% by volume of the cumulative distribution curve. From the same viewpoint, the particle size distribution of the solid fuel (before pulverization) is preferably such that particles having a particle size of 1.0 mm or more and less than 16 mm are 70% by mass or more of the whole solid fuel, and 75% by mass or more. More preferably. The average particle size of the solid fuel after pulverization is preferably 500 μm or less, and more preferably 100 μm or less. The solid fuel having such a fine average particle diameter is excellent in handleability and can be used for various applications. In addition, the average particle diameter and particle size distribution of solid fuel can be measured using a commercially available particle size analyzer.

  In the solid fuel of the present embodiment, the total amount of at least one of pulverized coal and petroleum coke powder is 50 to 500 parts by mass, preferably 50 to 200 parts by mass, and more preferably 80 to 150 parts by mass with respect to 100 parts by mass of the thermoplastic. It can be manufactured by a manufacturing method including a step of mixing and heating at a mass ratio of parts, melting a thermoplastic plastic, and then cooling and re-solidifying. Such a solid fuel can achieve both excellent ignitability and formation of a high temperature field at a high level, and has further excellent combustibility. In addition, since the pulverized coal and petroleum coke (and / or the pyrolyzed product of pulverized coal and petroleum coke) surround the re-solidified product of the thermoplastic plastic, solid fuel (thermoplastic plastic) is contained in the heating device. Can be prevented from fusing, or solid fuel can be fused and agglomerated.

  In addition, since the solid fuel of this embodiment can be manufactured using both petroleum coke powder and pulverized coal, manufacturing cost can be reduced sufficiently. Moreover, it can be set as the solid fuel which has desired combustibility by adjusting suitably the ratio of petroleum coke powder and pulverized coal according to the use to be used.

  Here, the ratio of volatile matter and fixed carbon (fuel ratio) of the solid fuel varies depending on the amount of pulverized coal and petroleum coke to the plastic that is input to the heating process, but also depends on the fuel ratio of the pulverized coal and petroleum coke itself. Is done. In particular, since petroleum coke is obtained by dry distillation of petroleum, the amount of residual volatile matter changes depending on the degree of dry distillation of petroleum, and the fuel ratio of petroleum coke also changes. Therefore, a solid fuel having a desired fuel ratio can be obtained by measuring a fuel ratio contained in pulverized coal and petroleum coke used in advance and appropriately setting a mixing ratio of pulverized coal and petroleum coke.

  When manufacturing the solid fuel of this embodiment, it is preferable to heat the mixture containing a thermoplastic and pulverized coal at a heating temperature of 250 to 350 ° C. At this heating temperature, some coal and petroleum coke do not melt and do not pyrolyze depending on the type. Among thermoplastics, thermoplastics containing chlorine, such as vinyl chloride, are solid, but other thermoplastics are often melted and liquefied. For this reason, when such a thermoplastic plastic is used as a raw material for solid fuel, a melt of the thermoplastic plastic is fused inside the heating device, or the thermoplastic plastics are fused together to form an aggregate. To do.

  However, the solid fuel of this embodiment contains pulverized coal, petroleum coke powder, or a thermal decomposition product thereof, and adheres to the surface of the melted thermoplastic plastic. That is, a pyrolyzate or the like adheres to the surface of the molten thermoplastic plastic, and a layer (second phase described later) mainly composed of the pyrolyzate or the like is formed on the molten thermoplastic surface. The presence of this second phase can reduce fusion with heating devices and other bulk plastic melts. Therefore, when the solid fuel is produced using only a thermoplastic resin (polyethylene, polypropylene, polystyrene, polyamide, etc.) that does not contain chlorine, such as vinyl chloride, the effect of the solid fuel production method of the present embodiment is more remarkable. It becomes.

  The structure of the solid fuel having the first phase and the second phase can be confirmed by observing a cross section of the solid fuel with a scanning electron microscope (SEM). The first phase may contain a pyrolyzed product or the like as a subcomponent in addition to the re-solidified product of the thermoplastic resin as the main component. Further, the second phase may contain a re-solidified product of a thermoplastic plastic as an auxiliary component in addition to at least one selected from pulverized coal, petroleum coke powder and thermal decomposition products thereof as main components.

  In a solid fuel, if the total mass ratio of pyrolyzate or the like is excessive, not only the waste cannot be effectively used but also sufficiently excellent ignitability tends to be impaired. On the other hand, if the total mass ratio of pyrolyzate or the like is too small, the ratio of fixed carbon tends to decrease and it becomes difficult to form a sufficiently high temperature field. From such a viewpoint, the ratio of the plastic heat-treated product is preferably 15 to 60% by mass, more preferably 20 to 50% by mass, based on the total of the plastic heat-treated product and the pyrolyzed product. More preferably, it is 20-40 mass%.

  The mass ratio of the sum of pulverized coal and its pyrolyzate to the sum of petroleum coke powder and its pyrolyzate is preferably 0.5 to 3.0, more preferably 0.8 to 2.0, More preferably, it is 1.0-1.5. If the mass ratio is too small, the content of pulverized coal and its pyrolyzate tends to be small, and it tends to be difficult to form an excellent high-temperature field. If the mass ratio is too large, petroleum coke powder And the content rate of the thermal decomposition thing decreases, and it exists in the tendency for the outstanding ignitability to be impaired.

  Next, a preferred embodiment of the method for producing a solid fuel of the present invention will be described.

  FIG. 1 is a process diagram of a method for producing a solid fuel according to the present embodiment. The solid fuel production method of the present embodiment is a charging step in which a plastic containing thermoplastic plastic, and pulverized coal obtained by pulverizing coal and petroleum coke powder obtained by pulverizing petroleum coke are charged into a heating device. And a mixing step of mixing a thermoplastic and pulverized coal and petroleum coke powder to obtain a mixture, and heating the mixture to thermally decompose pulverized coal and / or pulverized coal, and petroleum coke powder and / or petroleum coke powder. And a heating step for obtaining a solid fuel containing the pyrolyzate. Details of each step will be described below.

  In the charging step, the plastic containing the thermoplastic plastic, the pulverized coal and the petroleum coke powder, the total amount of the pulverized coal and the petroleum coke powder is 50 to 500 parts by mass, preferably 50 to 200 parts by mass with respect to 100 parts by mass of the plastic. More preferably, it is added at a ratio of 80 to 150 parts by mass. Coal and petroleum coke have less volatile content than plastic, and conversely plastic has less fixed carbon than coal and petroleum coke. Therefore, if the total input ratio of pulverized coal and petroleum coke powder to plastic is too high, not only can the waste be effectively utilized, but the excellent ignitability of the resulting solid fuel tends to be impaired. On the other hand, if the total charge ratio of pulverized coal and petroleum coke powder to the plastic is too low, the melted thermoplastics are fused together in the heating process, and the resulting heated product becomes agglomerated, making handling difficult. Tend to be. In addition, the thermoplastic resin melted on the heating furnace wall surface tends to be fused to easily damage the equipment. This is because the amount of pulverized coal, petroleum coke powder, and / or thermal decomposition products thereof adhering to the surface of the molten thermoplastic plastic is reduced, and pulverized coal, petroleum coke powder, and / or This is because the formation of these pyrolyzate phases (second phase) becomes insufficient.

  The water content of the pulverized coal in the charging step is 0 to 50% by mass, preferably 0 to 30% by mass, and more preferably 0 to 20% by mass. From the viewpoint of obtaining a solid fuel with further excellent combustibility, pulverized coal having a high calorific value (air-dried base) of preferably 20,000 kJ / kg or more, more preferably 22,000 kJ / kg or more is used. Moreover, from the viewpoint of obtaining a solid fuel excellent in ignitability, pulverized coal having a volatile content of preferably 10 to 50 mass%, more preferably 15 to 45 mass% is used.

  Further, pulverized coal having a fixed carbon content of preferably 30 to 70% by mass, more preferably 40 to 65% by mass is used. If the fixed carbon content of the pulverized coal becomes too small, it tends to be difficult to form a high-temperature field with the obtained solid fuel, and if the fixed carbon content of the pulverized coal becomes too large, the volatile matter becomes relatively volatile. There is a tendency that the excellent ignitability of the obtained solid fuel is impaired.

  The type of pulverized coal used in the production method of the present embodiment is not particularly limited, and from the viewpoint of obtaining a solid fuel having further excellent combustibility, fuel ratio (numerical carbon content divided by volatile matter) such as bituminous coal and anthracite coal. ) Having a large amount of fixed carbon, that is, high-grade coal can be suitably used. On the other hand, low-grade coals such as lignite, subbituminous coal, and peat may be used from the viewpoint of producing solid fuel at low cost.

  In general, low-grade coal often has a high water content. Low-grade coal with a high water content has many micropores, and moisture is retained in these micropores. When such low-grade coal is crushed and moisture is dried, the micropores are exposed on the surface, so low-grade coal with many micropores and high water content has a specific surface area compared to coal with few micropores. growing.

  Therefore, by heating low-grade coal with a high water content together with the thermoplastic, the molten thermoplastic is introduced into the micropores, and the micropores are closed, thereby exposing the micropores during drying and grinding. Reduce. This makes it possible to reduce the specific surface area of the solid fuel pulverized product of the present embodiment as compared with a pulverized product of low-grade coal having a high water content. Thereby, generation | occurrence | production of a dust explosion can fully be suppressed.

  Similarly, since petroleum coke has many micropores, the specific surface area at the time of pulverization can be reduced in the same manner as coal with many micropores by closing the micropores with molten thermoplastic.

  Some low-grade coals have a high oxygen content. Such low-grade coal with a high oxygen content tends to have many oxygen functional groups. Since the oxygen functional group has high hydrophilicity and high self-ignitability, a pulverized product of low-grade coal having a high oxygen content has high hydrophilicity and high self-ignition properties. However, since the solid fuel of the present embodiment has a surface that is coated with a molten plastic so that the exposure of oxygen functional groups is suppressed, even when low-grade coal with many oxygen functional groups is used, it is hydrophilic. And self-ignitability is reduced. In particular, when a solid fuel is pulverized to obtain a fuel, the specific surface area is increased by pulverization, so that the self-ignitability reducing action by suppressing the exposure of oxygen functional groups is more effective.

  In addition, the average particle diameter of pulverized coal is preferably 10 to 1000 μm, and more preferably 50 to 500 μm. If the average particle size of the pulverized coal becomes too large, the thermoplastic resin in the heating device tends not to be sufficiently suppressed. On the other hand, when the average particle diameter of pulverized coal becomes too small, handling of raw materials tends to be difficult.

  The water content of the petroleum coke powder in the charging step is 0 to 50% by mass, preferably 0 to 30% by mass, and more preferably 0 to 20% by mass. From the viewpoint of obtaining a solid fuel with further excellent combustibility, petroleum coke powder having a high calorific value (air-dried basis) of preferably 25,000 kJ / kg or more, more preferably 30,000 kJ / kg or more is used. Also, from the viewpoint of obtaining a solid fuel having excellent ignitability, petroleum coke powder having a volatile content of preferably 5 to 30% by mass, more preferably 10 to 20% by mass is used.

  Moreover, the content rate of fixed carbon of petroleum coke powder becomes like this. Preferably it is 50-95 mass%, More preferably, it is 60-90 mass%. If the content of fixed carbon in petroleum coke powder becomes too small, it tends to be difficult to form a high-temperature field with the obtained solid fuel, and if the content of fixed carbon in petroleum coke powder becomes too large, The excellent ignitability of the solid fuel obtained by reducing the volatile content tends to be impaired.

  The kind of petroleum coke powder used in the production method of the present embodiment is not particularly limited, and a commercially available petroleum coke produced with a normal coke production apparatus and pulverized with a roller mill or the like can be used. The average particle size of the petroleum coke powder is preferably 10 to 1000 μm, more preferably 50 to 500 μm. When the average particle size of the petroleum coke powder becomes too large, the thermoplastic plastics in the heating apparatus tend not to be sufficiently suppressed. On the other hand, if the average particle size of petroleum coke powder becomes too small, handling of raw materials tends to be difficult.

  A normal waste plastic can be used as the plastic. Waste plastics are usually discarded from general-purpose plastics, and most of the general-purpose plastics are thermoplastic.

  The waste plastic of the present embodiment is added with a thermoplastic resin (which is the same component as the thermoplastic plastic of the present embodiment) and / or an elastomer. As the thermoplastic resin and elastomer to be added and blended, it is desirable to use the same resin or the same resin as the resin material of the synthetic resin product. Accordingly, examples of thermoplastic resin materials that can be used to recycle pulverized waste plastic materials include olefin resins (eg, high density polyethylene, low density polyethylene, crystalline polypropylene), polycarbonate resins, polyurethane resins- Styrene resins, ABS resins (acrylonitrile-butadiene styrene resins), polyester resins such as polybutylene terephthalate and polyethylene terephthalate; polyphenyl ether resins such as modified polyphenylene ether and polyphenylene sulfide; polyacrylics such as polymethyl methacrylate Acid resins; polyamide resins such as 6-nylon, 66-nylon, 12-nylon, 6 / 12-nylon; polysulfone and the like can be mentioned.

  Elastomer is a thermoplastic low crystalline elastomer that does not have a clear yield point, or a thermoplastic amorphous elastomer that does not have a clear melting point and yield point, and an elastomer or rubber that has rubber elasticity at room temperature should be used. Can do. Specific examples of the elastomer that can be used include thermoplastic elastomers such as styrene elastomers, olefin elastomers, polyester elastomers, polyamide elastomers, and polyurethane elastomers. An elastomer may be used individually by 1 type and may be used in combination of 2 or more type.

  Styrene elastomers include butadiene-styrene copolymers (including all random copolymers, block copolymers, graft copolymers, etc.) and hydrogenated products thereof, styrene butadiene styrene copolymers (SBS, etc.) , Hydrogenated styrene-butadiene styrene copolymers (such as SEBS), isoprene-styrene copolymers (including all random copolymers, block copolymers, graft copolymers, etc.) and their hydrogenated products, hydrogenated Styrene-isoprene copolymer (SEPS, etc.), hydrogenated styrene-vinylisoprene copolymer (V-SEPS, etc.), styrene isoprene-styrene copolymer (SIS, etc.), hydrogenated styrene-isoprene-styrene copolymer ( SEPS etc.), hydrogenated styrene-butadiene olefin crystal block copolymer (SEBC etc.), etc. It can be used.

  As the polyolefin-based elastomer, an amorphous or low-crystalline polyolefin-α-olefin copolymer, a mixture of polyolefin and olefin rubber, or the like can be used. Specifically, natural rubber, isoprene rubber, butadiene rubber, butyl rubber, ethylene / propylene elastomer, ethylene / propylene / diene terpolymer elastomer, ethylene / 1-butene elastomer (EBM, EBS, etc.), ethylene / hexene elastomer , Ethylene / octene elastomer, propylene / 1-butene elastomer and other copolymer elastomers of ethylene and C3-C12 α-olefins, propylene and C2-C12 α-olefins (excluding C3) And polyolefin elastomers such as copolymer elastomers. Furthermore, examples of the polyolefin-based elastomer include hydrogenated acrylonitrile rubber, acrylonitrile butadiene rubber, epichlorohydrin rubber, acrylic rubber, chloroprene rubber and the like. Examples of elastomers include polyolefins such as copolymer elastomers of ethylene and α-olefins having 3 to 12 carbon atoms, and copolymer elastomers of propylene and α-olefins having 2 to 12 carbon atoms (excluding carbon number 3). Based elastomers can be preferably used.

  As the polyester elastomer, an elastomer made of a polyester-polyether copolymer, a polyester-polyester copolymer, or the like can be used.

  As the polyamide-based elastomer, an elastomer made of a polyamide-polyester copolymer, a polyamide-polyether copolymer, or the like can be used. One of the above elastomers may be used alone, or two or more may be used in combination.

  The waste plastic may contain other plastics and may contain a small amount of waste other than plastic as impurities. Impurities are crushed to a predetermined size together with waste plastics, and even if impurities such as metal pieces and thermosetting plastics are included, they adhere to the molten block of thermoplastic or the inside Is incorporated into the solid fuel.

  In addition, in the heating process (described later) of the present embodiment, heating is performed at 300 ° C. to 350 ° C. for desalting, and usually there are many polyethylene, polypropylene, polystyrene, and the like that melt at 300 ° C. to 350 ° C. In the case of contained waste plastic, fusion is likely to occur in the heating process. In that case, the fusion prevention effect by pulverized coal becomes more remarkable as in this embodiment.

  From the viewpoint of obtaining a solid fuel that is more excellent in combustibility, the high calorific value (air-dry basis) of the entire plastic is preferably 25,000 to 40,000 kJ / kg, more preferably 30,000 to 40,000 kJ / kg. is there. Further, from the viewpoint of obtaining a solid fuel having excellent ignitability, the content of volatile components in the entire plastic is preferably 70 to 95% by mass, more preferably 80 to 90% by mass.

  In the mixing step, the plastic, pulverized coal and petroleum coke powder charged in the charging step are mixed. Usually, substances containing a large amount of carbon, such as pulverized coal, do not have very good wettability with molten plastic. Therefore, by mixing the pulverized coal and petroleum coke powder and the plastic in the mixing step before the heating step, it is possible to suppress separation of the pulverized coal and petroleum coke powder and the thermoplastic plastic, and the thermoplastic plastic. It is possible to obtain a solid fuel in which the first phase mainly composed of the re-solidified product and the second phase mainly composed of the pyrolyzed product are well dispersed.

  FIG. 2 is a block diagram of a heating device used in the solid fuel production method of the present embodiment. The manufacturing method of the solid fuel of this embodiment can use a heating apparatus provided with a heating furnace usually used for melting waste plastic.

  As shown in FIG. 2, the waste plastic 10 that is a raw material is conveyed from a stock yard to a crusher 12 by a conveyance device 11 such as a conveyance crane, and is crushed into a predetermined size. The crushed crushed material is transferred to the heating furnace 20 by the transfer device 13. In the heating furnace 20, after the pulverized coal and / or petroleum coke and waste plastic are mixed, the waste plastic is heated and melted. When both pulverized coal and petroleum coke powder are used, they may be mixed in advance using another mixing device. In this case, a mixture of pulverized coal and petroleum coke powder may be prepared by simultaneously mixing coal and petroleum coke.

  In the heating step, the mixture is heated to make the thermoplastic plastic into a melt, and then cooled to obtain a solid fuel containing a resolidified product, a pyrolyzed product, and the like that are solidified. In addition, you may cool after a heating within a heating process, and you may provide the cooling process which cools the heating thing containing the melted thermoplastics after a heating process separately. Since pulverized coal and petroleum coke powder are not supposed to be thermally decomposed depending on the type and type of coal, pulverized coal and petroleum coke powder are pulverized coal and petroleum coke powder that are not thermally decomposed after heating, It becomes a mixture of cracked pulverized coal and pyrolyzed petroleum coke powder. Therefore, in the heating step, a granular solid fuel containing a re-solidified product of thermoplastic, a pyrolyzate, and the like is obtained.

  When the mixture is heated in the heating furnace 20, the thermoplastic plastic is melted, and a thermal decomposition product or the like is attached to the surface of the melted thermoplastic plastic. Thereafter, melting of the thermoplastic plastic proceeds, and pyrolyzate or the like adheres to the surface of the plastic melt. Then, when cooled, a solid fuel having a structure in which the surface of the re-solidified product (first phase) of the thermoplastic resin is covered with a thermal decomposition product (second phase) can be obtained.

  FIG. 3 is a scanning electron microscope (SEM) photograph (magnification: 150 times) showing the cross-sectional structure of the solid fuel of the present embodiment. The solid fuel obtained by the production method of the present embodiment is mainly composed of the first phase 100 mainly composed of a re-solidified product obtained by heating and melting a thermoplastic plastic and then cooling, and a pyrolyzed product. The second phase 200 is used as a component, and the second phase 200 is provided so as to cover the periphery of the first phase 100. By having such a structure, the solid fuel of the present embodiment is sufficiently suppressed from being fused into the apparatus and has better combustibility.

  As the heating furnace 20, a rotary heating furnace, for example, an indirect heating rotary kiln type heating furnace can be used. By using such a heating furnace, it is possible to heat a mixture of a crushed thermoplastic plastic and pulverized coal and petroleum coke powder. The pulverized thermoplastic material, pulverized coal, and petroleum coke powder may be mixed before being put into the heating furnace 20 or after being put into the heating furnace 20. From the viewpoint of obtaining a solid fuel that is as uniform as possible, the heating in the heating furnace 20 is preferably performed while mixing a crushed thermoplastic plastic, pulverized coal, and petroleum coke powder.

  The mixture containing the crushed thermoplastic material, pulverized coal, and petroleum coke powder is heated by the heating furnace 20. The heating temperature in the heating furnace 20 is 250 to 500 ° C, preferably 250 to 450 ° C, more preferably 280 to 400 ° C, and particularly preferably 300 to 350 ° C. If the heating temperature is too high, the volatile content of the obtained solid fuel is reduced, the yield of the solid fuel is lowered, and the excellent combustibility of the solid fuel tends to be impaired. On the other hand, when the thermoplastic plastic contains a plastic containing chlorine, if the heating temperature is too low, the residual amount of components such as chlorine in the solid fuel tends to increase.

  The heating time for heating to the above heating temperature in the heating furnace 20 is 30 to 120 minutes, preferably 45 to 90 minutes. When the heating time is too long, the volatile content of the obtained solid fuel is decreased, and the yield of the solid fuel tends to be lowered. On the other hand, when the heating time is too short, dechlorination of the plastic becomes insufficient, and the residual amount of components such as chlorine tends to increase in the solid fuel. In addition, it is preferable that a solid fuel contains the pulverized coal and / or petroleum coke powder which are not thermally decomposed from a viewpoint of obtaining the solid fuel which has the further outstanding combustibility with high yield. Such a solid fuel can be obtained by adjusting the heating temperature and / or the heating time in the heating step.

  The heating in the heating furnace 20 is preferably performed under a pressure less than atmospheric pressure. This facilitates the discharge of tar components generated by the thermal decomposition of the plastic to the outside of the heating furnace. As a result, the amount of the tar component present on the surface of the thermoplastic melt is reduced, and the fusion property of the surface of the thermoplastic melt is reduced. Therefore, the thermal decomposition product etc. (second phase) covering the thermoplastic re-solidification product (first phase) is suppressed, and excessive adhesion of the thermal decomposition product etc. to the surface of the thermoplastic melt is suppressed. It can suppress that the thickness of becomes too large. By such an action, the particle diameter of the finally obtained solid fuel can be reduced.

  Specifically, the heating in the heating furnace 20 is preferably performed under a reduced pressure of preferably 99 kPaA or less, more preferably 98 kPaA or less. In addition, although there is no minimum in particular in the pressure in the heating furnace 20, it is preferable that it is 90 kPaA or more from a viewpoint of the pressure | voltage resistance of an installation.

  The oxygen gas concentration inside the heating furnace 20 is preferably 10 to 18% by volume, more preferably 14 to 18% by volume. If the oxygen gas concentration becomes too high, oxidation of at least one of thermoplastic, pulverized coal, and petroleum coke powder proceeds, and the yield of the obtained solid fuel tends to be low. On the other hand, if the oxygen gas concentration becomes too low, the oxidation of the tar content generated by the thermal decomposition of the plastic is not promoted, the residual amount of tar increases, and fusion of the molten thermoplastic plastic tends to occur. is there.

  FIG. 4 is a schematic diagram showing an example of a stirring plate inside a rotary kiln-type heating furnace that is preferably used in the method for producing a solid fuel according to the present embodiment. The stirring plate (lifter) 30 is provided so as to extend along the axial direction of the heating furnace 20. By providing such a stirring plate 30, the raw materials (thermoplastic, pulverized coal, and petroleum coke powder) charged into the heating furnace 20 can be stirred and mixed smoothly. The number of the stirring plates 30 installed is appropriately set depending on the scale of the heating furnace and the like. For example, if the inner diameter of the heating furnace 20 is about 50 mm to 300 mm, it is preferable to provide two to four stirring plates 30 as shown in FIGS. 4 (a) to 4 (c). If it is about 600 mm, it is preferable to provide eight stirring plates 30 as shown in FIG.

  The stirring plate 30 is preferably attached at a pitch of about 0.3 to 3 times its height h. Further, the height h of the stirring plate 30 is 10% to 30% with respect to the inner diameter of the heating furnace 20 until the thermoplastic plastic contained in the raw material (mixture) is softened and granulated with pulverized coal and petroleum coke powder. The size is preferably about%. Thus, by using the kiln having the stirring plate 30 inside, the thermoplastic plastic, pulverized coal and petroleum coke powder charged into the heating furnace 20 are scraped up by the stirring plate 30 as the kiln rotates, It will be heated while being mixed.

  In the method for producing a solid fuel according to the present embodiment, a thermoplastic plastic containing chlorine such as vinyl chloride (waste plastic containing vinyl chloride or the like) can be easily treated. That is, when waste plastic containing chlorine such as vinyl chloride is heated, the chlorine becomes hydrogen chloride gas and is removed (desalted) from the solid raw fuel. Thereby, a solid fuel with a sufficiently reduced chlorine content can be obtained. However, if the chlorine content in the waste plastic becomes excessive, chlorine content remains in the generated solid raw fuel, and the equipment obtained using the equipment (for example, a cement production apparatus or a power generation boiler) using the solid fuel. It can adversely affect quality (eg cement). Therefore, it is preferable that the amount of chlorine contained in the raw material plastic is small. That is, in the charging step, it is preferable to input only a thermoplastic plastic that does not contain chlorine, such as vinyl chloride. Specifically, the chlorine content in the thermoplastic used as a raw material is 30% by mass or less, preferably 10% by mass or less. In addition, from the viewpoint of effectively using waste plastic such as vinyl chloride, the chlorine content of the raw material thermoplastic is 1% by mass or more, more preferably 2% by mass or more.

  Note that thermoplastics containing chlorine, such as vinyl chloride, become carbon-based solids when dechlorination (thermal decomposition) begins. A particularly preferable temperature range in the heating step of the present embodiment is 300 to 350 ° C. In this temperature range, the thermoplastic plastic containing chlorine is usually solid. Therefore, in the above temperature range, the thermoplastic plastic containing chlorine is not normally melted and is not fused in the apparatus.

  On the other hand, other thermoplastics are melted and liquefied in the temperature range (300 to 350 ° C.), and are fused when added to the heating furnace 20 without adding pulverized coal and petroleum coke powder. . Therefore, in this embodiment, by adding pulverized coal and petroleum coke powder, the pulverized coal and petroleum coke powder adhere to the periphery of the molten thermoplastic plastic, and are easier to melt than chlorine-containing plastics such as vinyl chloride. Even with thermoplastics, it is possible to produce a solid fuel while avoiding fusion.

  Thus, in the case of producing a solid fuel using only a thermoplastic resin (polyethylene, polypropylene, polystyrene, polyamide, polyester, etc.) that does not contain chlorine, such as vinyl chloride, the effect of the solid fuel production method of the present embodiment is effective. It becomes more prominent.

  In the production method of the present embodiment, the yield of the product (solid fuel) is 70% by mass or more, preferably 75% by mass or more, more preferably, with respect to the entire raw material to be charged (mixture in the mixing step). It is 78 mass% or more. Thus, by maintaining the product yield high, a solid fuel having a sufficiently high volatile content and good combustibility can be obtained. In addition, the yield of a product can be adjusted by changing the heating temperature and heating time in a heating furnace.

  The heated product (solid fuel) generated in the heating process is discharged from the heating furnace 20 as a product, cooled by a cooling device (not shown), and transferred to a subsequent collection / separation device as necessary.

  On the other hand, the pyrolysis gas containing tar generated by heating the mixture in the heating furnace 20 is burned in a combustion chamber (not shown) and completely decomposed. When waste plastic containing chlorine such as vinyl chloride is used as a raw material, hydrogen chloride contained in the combustion exhaust gas is recovered by the exhaust gas cleaning device 23.

  The solid fuel obtained in the heating step preferably contains, as a main component, a resolidified product obtained by cooling after the thermoplastic plastic melts, a thermal decomposition product, and the like. In addition to the main component, a small amount of thermosetting plastic that is not thermally decomposed may be contained.

  Some types of coal and petroleum coke powder are not thermally decomposed even when heated to 300 to 350 ° C. (particularly preferred temperature range in the heating step of the present embodiment). Therefore, the pulverized coal and petroleum coke powder included in the main component may be a mixture of pyrolyzed coal and non-pyrolyzed coal.

  You may perform the grinding | pulverization process which grind | pulverizes the obtained solid fuel after a heating process. In the pulverization step, the pyrolyzate obtained in the heating step is pulverized and granulated to a desired size using a normal pulverizer. Thereby, a solid fuel having a desired particle size can be obtained.

  Prior to the pulverization step, the solid fuel obtained from the heating furnace 20 via a cooling device may be separated into one having a large particle size and one having a small particle size by means such as a vibrating sieve. In this case, those having a small particle diameter can be used as a solid fuel as they are.

  According to the method for producing a solid fuel of the present embodiment as described above, it is possible to perform fusion in the apparatus by using thermoplastic plastic, pulverized coal and petroleum coke powder as raw materials without performing any special pretreatment. Is suppressed, and a solid fuel having good handleability and good combustibility can be obtained in a high yield.

  The obtained solid fuel can be supplied to a calcining furnace of a cement production apparatus, a kiln of a rotary kiln or a kiln bottom and burned, and used as a fuel. Further, it can be supplied to a power generation boiler as an alternative fuel for pulverized coal and burned.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments.

  The contents of the present invention will be described in more detail with reference to the contents of Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1
As raw materials, waste plastic including polyethylene (PS), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), vinyl chloride resin and ABS resin, commercially available pulverized coal, and commercially available petroleum coke powder were prepared. . An example of the composition of the prepared waste plastic is shown in Table 1. A plurality of types of waste plastics as shown in Table 1 were mixed to obtain a solid fuel material. Table 2 summarizes the properties of waste plastics, pulverized coal, petroleum coke powder, and organic powder obtained by mixing the petroleum coke powder and pulverized coal at a mass ratio of 35:65. Table 3 shows the particle size distribution of the petroleum coke mass. FIG. 5 is a graph showing the particle size distribution (volume basis) of the organic powder.

  Note that the ratio shown in Table 1 is merely an example because what kind of plastic is contained at what ratio is not uniquely determined due to the characteristics of the waste. As described above, when many plastics that are easily melted, such as polyethylene, polypropylene, and polystyrene, tend to be fused in the heating process, the effect of preventing fusion by pulverized coal becomes more prominent.

  In this example, the analysis of high calorific value (air-dried basis) was performed using 1013-J (device name, manufactured by Yoshida Seisakusho) in accordance with JIS M-8814. Industrial analysis (air-drying basis) was performed according to JIS M-8812. Elemental analysis (anhydrous base) was performed using MT-5 (device name, manufactured by Yanaco) in accordance with JIS M-8819. HGI (hard glove index, coal grindability index) measurement was performed in accordance with JIS M-8801. Measurement of average particle size and particle size distribution is performed by measuring a laser diffraction particle size distribution measuring device (manufactured by HORIBA, Ltd., device name: LA-920, solvent: 250 ml of pure water, relative refractive index 1.50, average particle size: 50% cumulative volume, Sample dispersion time: 3 minutes, measurement time: 20 seconds, number of measurement repetitions: 2 times, He—Ne laser, wavelength: 632.8 nm, output: 1 Mw, tungsten lamp 50 W). The average particle diameter was a particle diameter (median diameter) corresponding to 50% by volume of the cumulative distribution curve. The average specific surface area of pulverized coal (average particle size: 13 μm), and pulverized coal and petroleum coke powder (average particle size: 20 μm) is a commercially available specific surface area measuring device (manufactured by Shimadzu Corporation, device name: ASAP2420, using nitrogen gas, (BET specific surface area multipoint method).

  With respect to 100 parts by mass of the above-mentioned waste plastic, 100 parts by mass of the above-mentioned organic powder is put into a heating apparatus equipped with a rotary kiln type furnace (furnace diameter: 600 mm) as shown in FIG. The mixture of waste plastic and organic powder is heated in a mixed gas atmosphere of nitrogen and oxygen (oxygen concentration: 5% by volume or less, pressure: 98 to 101.3 kPaA) while mixing and heating. The heating process which heats for 50 minutes at 300 degreeC was performed.

  As a rotary kiln type heating furnace, one having a heat-resistant steel SUS310S container (4 scraping blades (stirring plates) (with blade height 70 mm × 4)) and an electric furnace for heating the container from the outside is used. The rotary kiln type heating furnace adjusted the sample temperature in the furnace by controlling the temperature outside the furnace while rotating so that the interval time between adjacent stirring plates was 0.1 minutes.

  After the heating process is completed in the rotary kiln type furnace, the product is cooled, pulverized coal, pyrolysis product of pulverized coal, petroleum coke powder, pyrolysis product of petroleum coke powder, resolidified waste plastic, and A solid fuel containing pyrolyzate of waste plastic was obtained. Table 4 shows the results of industrial analysis and elemental analysis of solid fuel. Table 5 shows the analysis results of the particle size distribution of the solid fuel (before pulverization).

In Table 4, the yield was determined by the following calculation formula (1).
Yield (mass%) = mass of solid fuel / (total mass of waste plastic, pulverized coal and petroleum coke powder charged into heating furnace) × 100 (1)

  The analysis result of the particle size distribution of the solid fuel (before pulverization) was as shown in Table 5. Thus, the solid fuel in Example 1 had a particle ratio of 1.0 mm or more and less than 16 mm of 85.8% by mass, and there was no large lump that would hinder transportation and storage. Further, when the proportion of fine particles is large, complicated processes are increased during transportation and storage, but in the solid fuel of Example 1, the proportion of fine particles of less than 1.0 mm is as small as 13.7% by mass. Improved handling in transportation, storage.

  The solid fuel obtained in Example 1 was pulverized, sieved, and subjected to thermogravimetric analysis (TG) using particles having a particle size of 500 to 1000 μm. Thermogravimetric analysis (TG) was measured using a MTC1000 (device name) manufactured by Mac Science Co., Ltd. in an air atmosphere at a heating rate of 10 ° C./min. For comparison, the same measurement was also performed on a raw material obtained by sieving petroleum coke powder (particle diameter of 45 μm or less) and a pulverized coal sieved (particle diameter of 45 to 90 μm). The thermogravimetric analysis of petroleum coke powder was performed in air at a heating rate of 5 ° C./min.

  FIG. 6 is a graph showing the thermogravimetric analysis (TG) result of the petroleum coke powder as a raw material, and FIG. 7 is a graph showing the thermogravimetric analysis (TG) result of the pulverized coal simple substance. FIG. 8 is a graph showing a thermogravimetric analysis (TG) result of a mixture of pulverized coal and petroleum coke powder as raw materials (mixing ratio in mass% is pulverized coal: petroleum coke = 65: 35). 2 is a graph showing the results of thermogravimetric analysis (TG) of the solid fuel of Example 1. In the solid fuel of Example 1, the inclination increases (starts combustion) from around 250 ° C. (see FIG. 9). On the other hand, the slope of oil coke alone increases (starts combustion) from around 420 ° C. (see FIG. 6), and the slope of pulverized coal alone increases from around 350 ° C. (starts combustion) (see FIG. 7). . In addition, in the mixture of pulverized coal and petroleum coke powder, the slope increased (started combustion) from around 400 ° C. (see FIG. 8). As a result, the solid fuel of Example 1 was pulverized coal, petroleum coke powder, and pulverized coal. It was confirmed that the ignitability was improved over any of the mixture of oil and petroleum coke powder.

  Thereby, even if it is a solid fuel using 100 mass parts of cheap waste plastics with respect to 100 mass parts (65 mass parts of pulverized coal, 35 mass parts of petroleum coke) of the mixture of pulverized coal and petroleum coke powder, pulverized coal alone As a result, it was possible to obtain a fuel having a combustion characteristic equivalent to or better than Moreover, since petroleum coke is cheaper than coal, a solid fuel having combustion characteristics equivalent to or better than that of pulverized coal alone can be obtained at a lower cost.

  20 ... heating furnace, 30 ... stirring plate (lifter), 100 ... first phase, 200 ... second phase.

Claims (15)

A solid fuel comprising a powder obtained from coal and petroleum coke, and a heat-treated product obtained by heating a plastic,
The powder contains at least one of pulverized coal obtained by pulverizing the coal and a thermal decomposition product of the pulverized coal, and at least one of petroleum coke powder obtained by pulverizing the petroleum coke and the thermal decomposition product of the petroleum coke powder. And
The plastic contains a thermoplastic;
The heat-treated product contains a re-solidified product obtained by cooling after melting the thermoplastic plastic,
A solid fuel having a volatile content of 10 to 80% by mass, a fixed carbon content of 10 to 80% by mass, and a moisture content of 0 to 50% by mass. A first phase containing the re-solidified product as a main component;
The solid fuel according to claim 1, further comprising: a second phase that includes the powder as a main component and covers an outer periphery of the first phase.   The content of C (carbon) is 70 to 90% by mass, the content of H (hydrogen) is 1 to 20% by mass, and the content of O (oxygen) is 0 to 30% by mass. The solid fuel described. In thermogravimetric analysis, where the temperature is raised at a heating rate of 10 ° C./min in air,
Based on the weight before the start of temperature rise,
4. The weight reduction rate (anhydrous ash basis) at 350 ° C. is 1 to 70%, and the weight reduction rate (anhydrous ash basis) at 500 ° C. is 15 to 100%. Solid fuel.   The solid fuel according to any one of claims 1 to 4, wherein the HGI is 15 to 40.   The solid fuel according to any one of claims 1 to 5, wherein the solid fuel is granular and has a particle diameter of 50 mm% or more of the whole having a particle diameter of 1.0 mm or more and less than 30 mm.   The solid fuel according to any one of claims 1 to 6, wherein the higher heating value is 20000 to 40,000 kJ / kg.   50 to 500 parts by mass of the pulverized coal and the petroleum coke powder are mixed in total with 100 parts by mass of the thermoplastic plastic, heated to melt at least a part of the thermoplastic plastic, and then the molten heat The solid fuel according to claim 1, which is obtained by cooling and re-solidifying and granulating a plastic plastic.   The solid fuel according to claim 1, wherein the plastic includes waste plastic.   The solid fuel as described in any one of Claims 1-9 whose average particle diameter of the said powder is 500 micrometers or less. A powder containing a thermoplastic plastic and a powder containing pulverized coal obtained by pulverizing coal and petroleum coke powder obtained by pulverizing petroleum coke are used as the powder 50 with respect to 100 parts by mass of the plastic. A charging step of charging the heating device at a ratio of ˜500 parts by mass;
A mixing step of mixing the plastic and the powder to obtain a mixture;
A solid fuel comprising: a re-solidified product obtained by heating the mixture to make the thermoplastic plastic into a melt and then solidifying the melt; and at least one of the powder and a thermal decomposition product of the powder And a heating step for obtaining a solid fuel.   The manufacturing method according to claim 11, wherein in the heating step, a volatile content of the solid fuel is set to 30 to 80% by mass.   The manufacturing method of Claim 11 or 12 whose average particle diameter of the said powder is 500 micrometers or less.   The manufacturing method as described in any one of Claims 11-13 which performs at least one part of the said heating process under a negative pressure.   The manufacturing method as described in any one of Claims 11-14 which performs the said heating process in the atmosphere whose oxygen gas concentration is 18 volume% or less.