JP5877007B2 - Method for producing solid fuel - Google Patents

Description

  The present invention relates to a method for producing a solid fuel. More specifically, the present invention uses a so-called “city waste” containing garbage disposed of from a general household as a main raw material, and has a more TECHNICAL FIELD OF THE INVENTION The present invention relates to a technology for efficiently producing solid fuel as a biomass fuel that is effective as a countermeasure for composting.

  Technology for treating municipal waste and recycling and recycling it is a technology for crushing, drying and separating the municipal waste and then shaping it into a crayon-like or cigar-like solid fuel (also known as "RDF") . An example of a specific production plant is shown in FIG. 3. This solid fuel is produced from the city by collecting municipal waste 1 containing 40 to 50% by mass of moisture by a truck 27 and collecting the garbage. It begins with charging in pit 2. In the garbage collection pit 2, the garbage is temporarily stored, and the water in the city garbage is removed. The moisture is collected in a sewage pit 3 attached to the garbage collection pit 2. Then, city garbage 1 (hereinafter also simply referred to as “garbage”) whose moisture has been reduced in the garbage collection pit 2 is collected in the garbage / hopper 5 via the crane 4. When the waste 1 cut out from the waste hopper 5 is crushed to a size of about 50 to 100 mm through a crusher 7 (for example, a biaxial special cutter) equipped with a magnetic separator 6 as a primary crushing and sorting means 17. At the same time, magnetic scrap iron and aluminum metal dust is excluded. The primary crushed garbage 1 is sent to the rotary kiln type drying furnace 8 and heated to 500-600 ° C. using hot air generated in the hot air furnace 23 using kerosene or heavy oil burner, Moisture removal is performed. Normally, the sewage 9 collected in the sewage pit 3 is also supplied to and processed in the drying furnace 8 for adjusting the drying temperature. In this drying stage, the water content of the waste is reduced to 10% by mass or less.

Next, the dried garbage 1 is sent to a crusher 7 (for example, a high-speed rotary cutter) equipped with a wind separator 10 that uses the difference in gravity as the secondary crushing and sorting means 18, and is crushed and inappropriate (non- Select combustion substances. At this stage, the trash 1 made suitable as a main raw material has a size of about 20 to 30 mm. Subsequently, slaked lime 11 that plays a role of preserving and deodorizing is added to the appropriate garbage 1 as necessary, and then weighed through a quantitative feeder 25 and compressed by passing through a die. After a fixed amount is supplied to the molding machine 12 and formed into a crayon shape or a cigar shape, it is cooled by a cooler 26 to become a solid fuel 13 as a final product. The average size of the final product is about 15 mm in diameter and about 50 to 60 mm in length. Here, the molding machine 12 to be used is not particularly limited, but suitable dust is sandwiched between a roller rotating at a low speed and a fixed disk-shaped die, and the reaction heat generated by the high pressure and friction of 200 kg / cm ^{2 at} the maximum. It is good to use what solidifies by action.

  In addition, the deodorizing apparatus 14, the dust collector 15, and the heat exchanger 16 are arrange | positioned in the required position of these manufacturing plants. Moreover, as a main user (user) of such a solid fuel 13, from the viewpoint that biomass fuel becomes a countermeasure against global warming than the use of fossil fuel, and can be cheaply and stably supplied, a paper manufacturer or RDF Such as a power plant.

  By the way, the solid fuel manufactured by this technique has a problem that some odor remains in the past. Therefore, as a countermeasure against deodorization, a deodorizing / preserving material is added to the main raw material municipal waste, or a large number of deodorizing apparatuses are installed in the manufacturing process, and currently, the odor problem is almost solved (for example, Patent Document 1 and Patent Document 2).

  However, recently, when a user uses the solid fuel 13 as a fuel for a boiler, there is a frequent problem that “the boiler tube is corroded and its life is shortened”. Subsequent investigation revealed that 0.6 to 1.0% by mass of chlorine was contained in the solid fuel 13 as a product, and that chlorine was a factor corroding the steel material of the boiler tube material. The user claims that if the chlorine content is reduced to 0.3% by mass or less, the life of the boiler tube is greatly improved, and therefore it is more preferable in use.

In addition, drying ovens used to remove moisture from municipal waste use a large amount of fossil fuels such as kerosene and heavy oil to generate hot air, and there is also a problem that CO ₂ generation is not friendly to the global environment. There was still room for remodeling.

Therefore, the present applicant tried to improve the production method so that not only the chlorine content, which is the above-mentioned problem, was reduced, but also contributed to global warming. A patent application was filed as Japanese Patent Application No. 2010-033797 on February 18, 2010. The details of the improved manufacturing method (see FIG. 2)
“(A) After passing through the garbage collection pit, primary crushing and sorting means, drying furnace, and secondary crushing and sorting means, the dried, pulverized and sorted powdery municipal waste is supplied to the molding machine and compressed into a predetermined shape. When making solid fuel, garbage is collected separately by combustible waste and plastic waste, and one or more means selected from the following three means are applied to reduce the chlorine content of the solid fuel. A method for producing a solid fuel, which is reduced to 0.3% by mass or less.

Mean 1: Before putting plastic / garbage separated and collected from the city into the garbage collection pit, vinyl chloride is removed from the plastic / garbage. Mean 2: Sewage collected in the sewage pit attached to the garbage collection pit The heat treatment is separately performed off-line without supplying to the drying furnace. Means 3: The biomass material is mixed with the garbage. It is identified by irradiation, and only the identified vinyl chloride is blown away with air for separation.

  (C) The mixing amount of the biomass material into the garbage of the means 3 is set to 20 to 50% by mass.

(D) A coconut shell is used for the biomass material, and the mixing is performed by the secondary crushing and sorting means.
It was something like that. In addition, mixing of the biomass material into the garbage has a role of diluting the chlorine content in the garbage.

  However, when this improved method was actually used and a solid fuel was prototyped using sewage sludge, foamed urethane, coconut shell, etc., as a mixed material for low chlorine dilution measures against garbage, the mass was 10 mass relative to the total amount of garbage. %, The chlorine content of the product solid fuel has been reduced from 0.60% by mass to 0.48% by mass, but adding more than that would cause the product to be powdered and difficult to mold became. In this case, the consumption of biomass materials such as sewage sludge, urethane foam and coconut shells was small, and the chlorine dilution effect was insufficient, resulting in technically unsatisfactory results.

Japanese Patent No. 3545504 Japanese Patent No. 2865541

  In view of such circumstances, the present invention further improves the technology of the above Japanese Patent Application No. 2010-033797, improves the moldability of dust, which is the problem, and reduces the chlorine content from the conventional level, resulting in global warming. It aims at providing the manufacturing method of the solid fuel which can contribute.

  The inventor has intensively studied to achieve the above object, and the results have been embodied in the present invention.

That is, the present invention sequentially supplies dust molding pits, primary crushing and sorting means, a drying furnace, and secondary crushing and sorting means to supply dried, pulverized and sorted powdery municipal waste to a molding machine, and compresses it to a predetermined value. When making solid fuel into a shape, the collection of garbage is separated and collected by combustibles and plastics and garbage, and one or more means selected from the following three means are applied, and the solid fuel contains chlorine In the method for producing a solid fuel in which the amount is reduced to 0.3% by mass or less,
The bark material is added to and mixed with the waste, and the amount added is adjusted to 10 to 50% by mass so that the crushing strength of the solid fuel as the product is 25.5 to 20 kg. This is a method for producing a solid fuel.

Mean 1: Remove vinyl chloride from the plastics / trash before the plastic / garbage collected separately from the city is put into the garbage collection pit. Mean 2: Sewage collected in the sewage pit attached to the garbage collection pit. and means for separately heating at off-line without supplying the drying oven 3: If this mixing biomass material to dust, the addition of pre-Symbol bark material, mixed, and go in the garbage pit, or A lignin adhesive may be used in place of the bark material.

  Since the bark material that contains lignin and is the bark of the tree was added and mixed in the garbage, the bark material exhibited an adhesive effect, and the formability of the solid fuel that was the product was improved. As a result, solid fuel with a chlorine content of 0.3% by mass or less can be stably reduced, and it is expected that not only paper companies and RDF power plants but also the use of solid fuel will expand from the past. The

It is a flowchart which shows the manufacturing plant of the solid fuel utilized for implementation of this invention. It is a flowchart which shows the solid fuel manufacturing plant described in Japanese Patent Application No. 2010-033797. It is a flowchart explaining the manufacturing process of the conventional solid fuel. It is a schematic diagram explaining the adhesion | attachment function of the lignin in a tree.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the inventor made a prototype of a solid fuel by using a conventional solid fuel production plant and adopting sewage sludge, urethane foam, coconut shell and the like as biomass materials to be added for low chlorine dilution with respect to garbage. As a result, the chlorine content of the solid fuel as a product was reduced from 0.60% by mass to 0.48% by mass, with the addition of up to about 10% by mass with respect to the total amount of garbage put into the production plant. It was found that when the above amount of biomass material was added, the product was pulverized and molding was difficult. This consumes less biomass material such as sewage sludge, foamed urethane, and coconut shells, and the effect of diluting chlorine is insufficient. That is, in order to stably produce a solid fuel having a chlorine content of 0.3% by mass or less desired by the user, it has been determined that it is necessary to further improve the formability of dust. Therefore, the inventor diligently studied to improve the formability of dust, and in view of constituent materials such as dust, if a substance having an adhesive function is added, the effect of adhering the dust is expressed, and the moldability is improved. I thought. And when a substance having an adhesion function was specifically sought, a lignin-based adhesive was used for the production of building material boards. Therefore, a substance containing lignin (usually 20-25 in plants) was used for molding of garbage. As a result, it was concluded that the use of bark material generated by the peeling of trees at a paper mill or the like is appropriate. The reason for this is that, as shown in FIG. 4, the lignin 38 of the tree exhibits the effect of the cellulose fiber 37 as a binder, and the tree fiber is formed. At this time, the hemicellulose 39 separately contained in the tree functions as a compatibilizing agent that improves the affinity between the cellulose fibers 37 and the lignin 38.

  In order to prove this, the inventor actually uses the process shown in FIG. 2 to add bark to trash and mix to replace the means 3 (mixing of biomass material) to produce a solid fuel. Tried. The results are shown in Table 1, and it was confirmed that not only the strength of the molded body could be sufficiently maintained by adding and mixing the bark material, but also the effect of diluting chlorine. In addition, the intensity | strength of Table 1 is a compressive strength, and is evaluated by the value of the load loaded before crushing.

  Therefore, the inventor considered that the formability of the dust would be improved if this bark material was added to and mixed with the garbage, and was completed as the first invention on condition that the means 1 to means 3 were also used. . In this case, the addition amount of the bark material 36 is preferably 10 to 50% by mass as a result of various trials, and this is the second aspect of the present invention. If it is less than 10%, the effect of improving the moldability is not sufficient, and if it exceeds 50%, the effect is saturated, and addition beyond that is meaningless.

  In addition, the addition position was tried as a position where the conventional biomass material indicated by symbol 30 in FIG. 2 is added. However, in order to improve the mixing state of the added bark material 36 and the garbage, the garbage on the upstream side is further improved. It turns out that the collection pit 2 is better. Therefore, as shown in FIG. 1, it is a third aspect of the present invention that a means for adding a bark material 36 (such as a hopper) is newly installed in the garbage collection pit 2 and used.

  Next, the inventor believes that if a bark material containing lignin is effective for moldability, a similar effect can be obtained by mixing a commercially available lignin-based adhesive into the trash, and the lignin adhesive is used instead of the bark material. The addition of an agent is the fourth invention. At that time, a method for adding the lignin-based adhesive to the waste is not particularly defined. This is because if the lignin-based adhesive is in a liquid state, it may be sprayed onto the dust, and if it is in a solid state, it may be pulverized into a powder and mixed with the dust. Of course, the amount added is smaller than that of the bark material, but the biomass material such as sewage sludge may serve as a chlorine-diluting substance for waste.

  Here, the means 1 means that before entering the manufacturing process comprising the conventional dust collection pit 2, the primary crushing and sorting means 17, the drying furnace 8, the secondary crushing and sorting means 18 and the molding machine 12, etc. It is to collect the collected waste separately from combustible waste and plastic waste. Specifically, as is clear from FIG. 1, combustible garbage (raw garbage, paper garbage, etc.) 31 and plastic garbage 32 are separately collected from the city, and the combustible garbage 31 is directly thrown into the garbage collection pit 2. However, the plastic trash 32 is put into another receiving hopper 33. Then, the plastic waste 32 is removed through an auxiliary crusher 34 equipped with a magnetic separator 6 to remove inappropriate materials such as metal, and then the vinyl chloride 21 is removed through a newly provided chlorinated plastic sorting device 35. Later, it was carried into the garbage collection pit 2.

  Next, the means 2 means that the sewage 9 collected in the sewage pit 3 in FIG. 3 is not supplied to the drying furnace 8 and the sewage 9 is conveyed off-line by the truck 27 as shown in FIGS. And heat treatment separately. This is because the amount of chlorine in the product can be reduced. Note that the heat treatment method is not particularly limited in the present invention.

The means 3 is a biomass material 30 that does not contain chlorine in the municipal waste 1 that has undergone the drying treatment.
Is to add. This is because the chlorine content of the product can be diluted (see FIGS. 1 and 2). In addition, although various things, such as a coconut shell, a sewage sludge, and wood scrap, exist as biomass material 30, in this invention, it is recommended to use the coconut shell which remains after extract | collecting palm oil from a coconut.

Municipal waste 1 separated and collected from the city was processed to produce solid fuel 13. The manufacturing process used at that time is based on the flow shown in FIG. 1 according to the present invention. The internal atmospheric temperature of the drying furnace 8 shown in FIG. 1 is 500 to 600 ° C., the pressurizing condition of the molding machine 12 is 200 kg / cm ² at the maximum applied pressure, and the size after the primary crushing and sorting 17 of the municipal waste 1 is 50. The size after ˜100 mm and secondary crushing and sorting 18 was 20-30 mm. Table 2 collectively shows other main manufacturing conditions and manufacturing results. In Table 2, the amount of municipal waste (% by mass) is the amount of municipal waste input to one operation, and the amount of additive to municipal waste (and the amount of biomass material added) is Material amount / (amount of municipal waste + amount of additive material) × 100). Further, in this example, in addition to the case where the manufacturing process of FIG. 3 was used as a conventional example, an invention in which lignin adhesive was added to municipal waste instead of bark material was carried out, and the results are shown in Table 3.

  From Table 2 and Table 3, when the production method of the solid fuel 13 according to the present invention is applied, not only the solid fuel 13 as an end product with improved dust moldability and excellent appearance is obtained, but also included therein. It is clear that the solid content of the chlorine content is reduced and the user's desired value of 0.3% by mass or less can be stably supplied.

DESCRIPTION OF SYMBOLS 1 Municipal waste 2 Waste collection pit 3 Wastewater pit 4 Crane 5 Waste / hopper 6 Magnetic separator 7 Crusher 8 Drying furnace 9 Wastewater 10 Wind separator 11 Slaked lime 12 Molding machine 13 Solid fuel 14 Deodorizer 15 Dust collector 16 Heat exchanger 17 Primary Crushing and sorting means 18 Secondary crushing and sorting means 19 Belt conveyor 20 Sensor 21 Vinyl chloride 22 Air outlet nozzle 23 Hot air furnace 24 Screen 25 Constant supply machine 26 Cooling machine 27 Truck 28 Signal 29 Air 30 Biomass fuel 31 Combustible waste 32 Plastic Garbage 33 Separate receiving hopper 34 Preliminary crusher 35 Chlorinated plastic sorting device 36 Bark material 37 Cellulose fiber 38 Lignin 39 Hemicellulose

Claims (3)

After passing through the garbage collection pit, primary crushing and sorting means, drying furnace, and secondary crushing and sorting means, the dried, pulverized and sorted powdery municipal waste is supplied to the molding machine and compressed into a solid fuel of a predetermined shape. At that time, the collection of garbage is separated and collected by combustibles and plastics and garbage, and one or more means selected from the following three means are applied, and the solid fuel has a chlorine content of 0.3 mass. In the method for producing a solid fuel that is reduced to less than
The bark material is added to and mixed with the waste, and the amount added is adjusted to 10 to 50% by mass so that the crushing strength of the solid fuel as the product is 25.5 to 20 kg. A method for producing a solid fuel.
Mean 1: Remove vinyl chloride from the plastics / trash before the plastic / garbage collected separately from the city is put into the garbage collection pit. Mean 2: Sewage collected in the sewage pit attached to the garbage collection pit. Is separately heated off-line without supplying it to the drying furnace.   2. The method for producing a solid fuel according to claim 1, wherein the bark material is added and mixed in the dust collection pit.   3. The method for producing a solid fuel according to claim 1, wherein a lignin adhesive is used instead of the bark material.

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