JP7754967B2 - Manufacturing method of resin composite products - Google Patents

Description

The present invention relates to a technology for manufacturing resin composite products that contribute to the realization of the Sustainable Development Goals (SDGs) by using by-products from coal-fired power generation.

Efforts are underway around the world to reduce CO2 emissions, which are believed to be the cause of global warming, and to create a society that reduces the burden on the environment. In this context, while some countries are trying to reduce their reliance on coal-fired power generation, emerging countries are seeking to make greater use of coal as an energy source from the perspectives of stable supply, economic efficiency, environmental compatibility, and safety.

Since the CO2 emissions from burning coal are higher than those from other fossil fuels, efforts are being made to reduce emissions by improving power generation efficiency in coal-fired power plants. Furthermore, to reduce the environmental impact, coal-fired power plants are equipped with desulfurization equipment that removes sulfur components from exhaust gases after combustion.

By-products of coal-fired power generation include fly ash, clinker ash, and other coal ash, as well as large amounts of gypsum produced in desulfurization equipment. Approximately 9 million tons of coal ash is generated annually from coal-fired power generation in Japan, with about 90% of that being fly ash. Furthermore, approximately 1.7 million tons of gypsum is generated annually from the desulfurization process in coal-fired power generation in Japan.

Fly ash is a spherical particle with a diameter of approximately 0.1 to 300 μm, and is industrially standardized after particle size adjustment (known as "JIS ash") for use as a cement raw material. Clinker ash, which has a porous structure, is widely used in golf courses and road subbases, intermediate layers for sports grounds, backfill materials for quay walls, and lightweight embankments such as terre armée, taking advantage of its excellent properties of light weight, drainage, breathability, water retention, and fertilizer retention. Gypsum is also mostly used as a blending aid for cement raw materials or in gypsum boards (see, for example, Non-Patent Documents 1 and 2).

Carbon Frontier Organization website (https://www.jcoal.or.jp/ashdb/whatash/ashoutline.html) Japan Cement Association website (https://www.jcassoc.or.jp/cement/1jpn/jc.html#03)

However, the reality is that many of the by-products of coal-fired power generation mentioned above are not used and are instead buried in dedicated disposal sites. Specifically, clinker ash that exceeds demand and fly ash that does not meet industrial standards (known as "JIS non-compliant ash") are subject to burial disposal. Looking at recent trends in coal ash use, it is predicted that dedicated disposal sites will become increasingly overwhelmed, and there is a need to secure capacity and improve environmental aspects.

Here, we distinguish between coal ash immediately after being discharged from coal-fired power plants and coal ash that has been buried in dedicated disposal sites as "new ash," and coal ash that has been buried in dedicated disposal sites as "pre-formed ash." If we could promote the use of pre-formed ash, it would not only help extend the life of current dedicated disposal sites, but would also have many benefits, such as allowing us to flexibly ship large amounts of existing stock in response to demand.

However, this explanation for prioritizing the use of existing ash over newly produced ash is far from being sufficiently rational or necessary. Furthermore, there is no mechanism in place to provide incentives to encourage the use of coal ash.

The present invention was made with these circumstances in mind, and provides a manufacturing technology for resin composite products that promotes the use of pre-made ash, a by-product of coal-fired power generation, and contributes to reducing carbon dioxide emissions in order to achieve the Sustainable Development Goals (SDGs).

The method for manufacturing a resin composite product according to the present invention includes the steps of recovering coal ash, which is the residue of coal combustion in thermal power generation; adjusting at least one of the particle size, blending, and moisture content of the recovered ash to produce recycled powder; and heating and kneading a mixture of the recycled powder and synthetic resin at a temperature at which the synthetic resin melts , and extracting a molten mixture. The recycled powder is further blended with a dispersion of at least one of layered silicate, polysaccharide nanofiber, and hydrophilic cellulose derivative dispersed in water or a polyhydric alcohol to produce the mixture .

This invention provides a manufacturing technology for resin composite products that promotes the use of pre-made ash, a by-product of coal-fired power generation, and contributes to reducing carbon dioxide emissions in order to achieve the Sustainable Development Goals (SDGs).

1 is a schematic diagram illustrating a method for manufacturing a resin composite product according to a first embodiment of the present invention; FIG. 10 is a side view showing a manufacturing apparatus for a resin composite product that is applied to the second and third embodiments of the present invention.

(First embodiment)
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a schematic diagram illustrating a method for manufacturing a resin composite product according to a first embodiment of the present invention (hereinafter simply referred to as "the manufacturing method"). This manufacturing method includes the steps of burying coal ash 25 (25a, 25b), which is the residue of coal combustion in a thermal power plant 10, in a dedicated disposal site 20, and recovering the resulting pre-formed ash 26 or metal sulfates 27 produced by desulfurizing coal combustion flue gas 24; adjusting at least one of the particle size, composition, and moisture content of the recovered pre-formed ash 26 or metal sulfates 27 to produce recycled powder 28; and heating and kneading a mixture 43 of the recycled powder 28 and a synthetic resin 29 at a temperature at which the synthetic resin 29 melts, and extracting a molten mixture 36.

As shown in Figure 1, in a coal-fired power plant 10, pulverized coal (not shown) is burned in a boiler 11, and the resulting energy is converted into electricity by a turbine 12 and a generator 13. As a result of this coal combustion, a large amount of coal ash 25 (25a, 25b) is produced, equivalent to approximately 10% of the coal. This coal ash 25 is then classified into fly ash 25a and clinker ash 25b.

The main components of these coal ashes 25 (25a, 25b) are silica (SiO ₂ ) and alumina (Al ₂ O ₃ ), accounting for 70 to 80%, and other components include iron oxide (Fe ₂ O ₃ ), calcium oxide (CaO), magnesium oxide (MgO), sodium oxide (Na ₂ O), potassium oxide (K ₂ O), etc.

Fly ash 25a is formed when particles of molten coal ash 25 float in the high-temperature combustion gas, cool at the low-temperature boiler outlet, and turn into glassy, spherical particles that are then collected by the electrostatic precipitator 14. This fly ash 25a is a mixture of spherical and irregular shapes with an average particle size of 10 to 30 μm.

Furthermore, the combustion flue gas 24 is released into the atmosphere from the chimney 15 after sulfur oxides (SOx) are absorbed in the flue gas desulfurizer 22. Metal sulfates 27 produced from the sulfur oxides (SOx) in the flue gas desulfurizer 22 are collected in the tank 23. Note that sulfur oxides (SOx) are produced when sulfur contained in coal is burned, and the type of flue gas desulfurizer 22 that absorbs these sulfur oxides (SOx) and produces metal sulfates 27 is not particularly limited.

The lime-gypsum method is a method in which limestone (CaCO ₃ ) is made into a slurry and reacted with SOx inside the flue gas desulfurizer 22 to recover gypsum (CaSO ₄ ) as metal sulfate 27. The magnesium hydroxide method is a method in which magnesium hydroxide (Mg(OH) ₂ ) is reacted with SOx inside the flue gas desulfurizer 22 to recover magnesium sulfate (MgSO ₄ ) as metal sulfate 27.

Since such metal sulfates 27 are hydrated, resin composite products containing them can be treated as non-flammable and flame-retardant products under the Fire Service Act by setting the oxygen index to 26 or higher. However, metal sulfates 27 tend to agglomerate, and to date, they have rarely been filled into resin composite products. However, by heating and kneading the molten mixture 36 together with a liquid medium (water), the dispersibility of the metal sulfates 27 can be improved. Furthermore, the liquid medium (water) retains water by hydrogen bonding with the metal sulfates 27, further improving the flame retardancy of the resin composite product. Furthermore, the hydrogen-bonded water also functions as a plasticizer, improving the toughness of the resin composite product.

The fly ash 25a collected by the electrostatic precipitator 14 is stored in a silo 16a as "raw powder" and then separated according to particle size by a classifier 21. The fine and coarse particles obtained by the classifier 21 are called fine fly ash _25a1 and coarse fly ash _25a2 , and are stored in separate silos _16a1 and _16a2 , respectively.

On the other hand, clinker ash 25b is formed when coal ash 25 particles inside the boiler 11 adhere to each other, forming porous masses that remain inside the boiler 11. This clinker ash 25b falls and accumulates in a water tank (clinker hopper 17) located below the boiler 11. It is then crushed into sand by a crusher (not shown), dehydrated in a dewatering tank 18, and stored in the sandy state in silo 16b.

In this way, the fly ashes 25a, _25a1 , _25a2 , clinker ash _25b , and metal sulfates 27 recovered from the combustion gas 24 and stored in the silos 16a, _16a1 , 16a2, 16b and tank 23 are shipped at appropriate times depending on their intended use.

However, the balance between supply and demand for the fly ash 25a and clinker ash 25b produced in this way is actually biased towards the supply side, so the excess fly ash 25a and clinker ash 25b produced and the fly ash _25a3 (JIS non-compliant ash) remaining in the classifier 21 are buried in a dedicated disposal site 20.

Coal ash 25 buried in the dedicated disposal site 20 in this way is called ready-made ash 26. In contrast, coal ash 25 stored in silos 16a, _16a1 , _16a2 , and 16b and retaining the properties it had immediately after discharge is called "new ash" to distinguish it. This ready-made ash 26 is characterized by less pozzolanic reactivity and greater stability when used compared to new ash, as a result of the pozzolanic action caused by natural moisture and pressure during the disposal process.

The resin composite product manufacturing apparatus 50A (50) (simply referred to as "manufacturing apparatus 50A") applied to the first embodiment is composed of a raw material supply unit 40A (40) and an extruder 30A (30). The raw material supply unit 40A includes an adjustment unit 41 that adjusts the particle size, composition, and moisture content of the pre-formed ash 26 recovered from the dedicated disposal site 20, and a resin container 45 that stores pelletized synthetic resin 29. A separate mixing tank (not shown) may be provided in which the recycled powder 28 and synthetic resin 29 are mixed to form a mixture 43.

Suitable synthetic resin 29 is a polyolefin-based thermoplastic resin such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), or ethylene-ethyl acrylate copolymer (EEA), molded into pellets.

In addition to these, other materials that have the property of flowing when heated and can generally be extruded can be used without particular restrictions, such as polycarbonate resin (PC), polyethylene terephthalate resin (PET), acrylic butylene styrene (ABS), polyvinyl chloride (PVC), polystyrene (PS), polyamide (PA), etc. Furthermore, synthetic resin 29 may be a mixture of two or more of these thermoplastic resins, or recycled products of these thermoplastic resins can also be used.

Here, the adjustment unit 41 uses equipment with various functions depending on the adjustment function to be performed. The properties of the ready-made ash 26 differ depending on the origin (fly ash 25a, _25a1 , _25a2 , _25a3 , clinker ash 25b) of the coal ash 25 buried in the dedicated disposal site 20. Therefore, the blending adjustment in the adjustment unit 41 involves mixing multiple types of coal ash 25 of different origins while adjusting the blending ratio according to the intended use.

The blending adjustment by the adjusting unit 41 may use not only existing ash 26 buried at the dedicated disposal site 20, but also new ash stored in silos 16a, _16a1 , _16a2 , 16b, etc. without being buried. Furthermore, the blending adjustment may also use incineration ash from combustion equipment. Furthermore, the blending adjustment may also use metal sulfates 27 (gypsum ( _CaSO4 ), magnesium sulfate ( _MgSO4 )) stored in the tank 23.

The particle size distribution of the pre-made ash 26 becomes coarse due to the granulation caused by the pozzolanic action that progresses during its residence at the dedicated disposal site 20. Therefore, particle size adjustment in the adjustment unit 41 specifically uses a high-speed rotary crusher such as a hammer mill or pin mill, or a container-driven mill that uses crushing media (rods, balls, beads, etc.) such as a rotary mill, vibration mill, or planetary mill, to cause the particles of the pre-made ash 26 to collide with each other and grind them, thereby miniaturizing the particles and achieving a uniform particle size distribution. This particle size adjustment can be made more efficient by blending coal ash 25 with a smaller particle size in advance.

In addition, it is known that the presence of a liquid medium such as water is effective in uniformly dispersing pre-formed ash 26 at a high blending ratio in synthetic resin 29 during the process of heating and kneading the molten mixture 36. This is because when pre-formed ash 26 powder, synthetic resin 29, and liquid medium are heated and kneaded in a sealed state, water acts to form a fine dispersed phase of pre-formed ash 26 in the fluid matrix phase of synthetic resin 29. In other words, the liquid medium prevents the powder from agglomerating in the synthetic resin fluid during heating and kneading, homogenizing the composite at a microscopic level. The pre-formed ash 26 powder is prevented from re-agglomerating by the action of the liquid medium in a high-temperature, high-pressure state in a sealed system, and is finely and uniformly dispersed in the molten matrix.

A certain amount of moisture may be added to the newly formed ash 26 during the burial period at the dedicated disposal site 20 or during the particle size adjustment process described above. Furthermore, because clinker ash 25b is crushed into sand using a crusher (not shown) in the presence of a large amount of water, it is stored in silo 16b in a moist state even after being dehydrated in the dehydration tank 18. On the other hand, raw powder fly ash 25a is stored in silo 16a in an almost completely dry state with no moisture content, as can be seen from the production process shown in Figure 1.

The adjustment unit 41 therefore adjusts the moisture content of the recycled powder 28 to an appropriate level. This adjustment of the moisture content of the recycled powder 28 includes not only the addition of new liquid medium (water, alcohol, etc.), but also the dehydration of moisture already contained in the powder.

In the above, the blending of recycled powder 28 has been explained on the assumption that pre-formed ash 26 is used as the main component. However, recycled powder 28 may also be blended using metal sulfate 27 produced in flue gas desulfurizer 22 and stored in tank 23 as the main component, without using pre-formed ash 26.

The extruder 30 is composed of an input section 31 into which a mixture 43 of recycled powder 28 and synthetic resin 29 is input; a cylinder 33 that forms a sealed container and has an input section 31 located upstream and a die section 35 located downstream from which a molten kneaded body 36 is extruded; a drive section 32 that rotates a screw (not shown) around its axis inside the cylinder 33 to extrude the heated mixture 43 from upstream to downstream to form the molten kneaded body 36; and a vent section 34 that opens the cylinder 33, which is a sealed container, to the atmosphere and allows moisture contained in the molten kneaded body 36 to be discharged to the outside.

The extruder 30 can be any suitable device that places the mixture 43 inside a sealed container, heats and kneads it at a temperature at which the synthetic resin 29 melts, and produces a molten kneaded mixture 36. Therefore, the kneading means is not limited to a continuous type like the illustrated extruder 30, and may be a batch type such as a Banbury, kneader, or roller, although not shown.

At the vent section 34, the liquid medium 37 contained in the molten kneaded material 36 is discharged to the outside of the sealed container at a pressure equivalent to atmospheric pressure. The molten kneaded material 36 thus dehydrated is removed from the most downstream end of the cylinder 33. The molten kneaded material 36 removed from the extruder 30 is then branched into bundles at the die section 35, cooled and solidified, and then shredded into pellet-shaped resin composite material.

The pellets formed in this manner are melted again using a known method and molded in a resin molding machine to form a resin composite product. Alternatively, the molten mixture 36 removed from the extruder 30 can be fed directly into a resin molding machine to form a resin composite product.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a side view showing a resin composite product manufacturing apparatus 50B (50) (hereinafter referred to as "manufacturing apparatus 50B") equipped with a raw material supply unit 40B (40) applied to the second embodiment of the present invention.

The raw material supply unit 40B (40) of the second embodiment differs from the raw material supply unit 40A of the first embodiment in that it is configured to blend a dispersion 48, in which at least one of metal sulfate 27, layered silicate, polysaccharide nanofiber, and hydrophilic cellulose derivative is dispersed in water or a polyhydric alcohol, with the recycled powder 28. Note that in Figure 2, parts that have the same configuration or function as those in Figure 1 are indicated by the same reference numerals, and redundant explanations will be omitted.

The raw material supply unit 40B of the second embodiment includes an adjustment unit 41 and resin container 45 common to the raw material supply unit 40A (Figure 1), as well as a supply unit 46 that supplies dispersion 48 and a mixing tank 42 that mixes the recycled powder 28 and dispersion 48. There are no particular limitations on the process by which the recycled powder 28, dispersion 48, and synthetic resin 29 are finally mixed into the mixture 43. While the embodiment shows an example in which the recycled powder 28 and dispersion 48 are mixed first and then the synthetic resin 29 is mixed, the recycled powder 28 and synthetic resin 29 may be mixed first and then the dispersion 48 may be mixed, or the dispersion 48 and synthetic resin 29 may be mixed first and then the recycled powder 28 may be mixed, or the dispersion 48, synthetic resin 29, and recycled powder 28 may be mixed together.

Bentonite, which is primarily composed of montmorillonite, is preferably used as the layered silicate. When layered silicate swells and gels in a liquid medium, it exfoliates into single layers, forming nano-sized sheets. When this gel-like layered silicate is mixed with pelleted synthetic resin 29, the viscosity of the gel-like layered silicate causes the layered silicate to spread onto the surface of the pelleted synthetic resin 29.

When the mixture 43 is kneaded at the melting temperature of the synthetic resin 29, the excess moisture (liquid medium) acts to uniformly disperse the recycled powder 28 into the molten synthetic resin 29. When the excess moisture contained in the molten mixture 36 is vaporized and discharged, the recycled powder 28 is finely and uniformly dispersed in the continuous phase of the synthetic resin 29. At this time, the nanosheets of the layered silicate bridge the molecular chains of the synthetic resin 29 and the recycled powder 28, thereby improving the interfacial adhesion between the synthetic resin 29 and the recycled powder 28. Similar to the layered silicate, the metal sulfate 27 also improves the interfacial adhesion between the synthetic resin 29 and the recycled powder 28.

Preferably, polysaccharide nanofibers are cellulose nanofibers, chitin nanofibers, or nanofibers with similar molecular chain structures. Because these polysaccharide nanofibers are highly hydrophilic, they are often defibrated using water as a dispersion medium, and may be prepared as a dispersion 48 dissolved in a liquid medium (water) from the beginning. The polysaccharide nanofibers are unevenly distributed at the interface between the synthetic resin 29 and the recycled powder 28, improving adhesion.

Hydrophilic cellulose derivatives are obtained by introducing functional groups or substituting atoms into the hydroxyl groups of cellulose molecules. A suitable example is cellulose ether, which is widely used as a thickener in food and pharmaceutical applications. Cellulose ether has a significantly greater affinity for water than cellulose fiber, so it dissolves in water to form dispersion 48.

Such cellulose ethers include methyl cellulose, ethyl cellulose, ethyl methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, benzyl cellulose, trityl cellulose, cyanoethyl cellulose, and aminoethyl cellulose. Furthermore, the hydrophilic cellulose derivative is not limited to such cellulose ethers, and any suitable derivative can be used as long as it can be dissolved in a solvent to form dispersion 48.

Glycols such as ethylene glycol and 1,4-butanediol are suitable polyhydric alcohols. Two or more of these polyhydric alcohols can be used. This polyhydric alcohol acts to uniformly disperse the recycled powder 28 in the molten mixture 36 that is being heated and kneaded. In this way, resin composite products manufactured using the dispersion 48 exhibit excellent mechanical strength.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a side view showing a manufacturing apparatus 50B (50) equipped with an extruder 30B (30) applied to the third embodiment of the present invention.

In the third embodiment, the extruder 30B differs from the extruder 30A of the first embodiment in that it is configured to perform dehydration at a set pressure higher than atmospheric pressure in a dehydration section 52 located above the outlet 55 for the molten kneaded material 36. Note that in Figure 2, parts that have the same configuration or function as those in Figure 1 are indicated by the same reference numerals, and redundant explanations will be omitted.

The extruder 30B shown in Fig. 2 has three dehydration sections 52 ( ₅₂₁ , ₅₂₂ , ₅₂₃ ) arranged in three stages. The moisture contained in the molten kneaded material 36 is sequentially discharged from the dehydration sections 52 ( ₅₂₁ , ₅₂₂ , ₅₂₃ ) in which the throttle amounts of the open valves 51 ( ₅₁₁ , ₅₁₂ , ₅₁₃ ) are adjusted. The most downstream dehydration section ₅₂₃ is provided with a pressure reducing pump 39 and a trap 38.

In Figure 2, the opening of the open valves 51 ( ₅₁₁ , ₅₁₂ , ₅₁₃ ) provided in each dehydration section 52 (521, 522, 523) is adjusted so that the internal pressure in the dehydration section 52 ( ₅₂₁ , ₅₂₂ , ₅₂₃ ) is set so that it slopes from upstream as P1 > P2 = P0 > P3. In this case, the open valve 51 for setting the internal pressures P2 and P3 is set to be fully open. Dehydration at a higher pressure than atmospheric pressure P0, such as this internal pressure P1, is effective in preventing excessive evaporation of water and suppressing aggregation of the filler when the molten kneaded body contains a large amount of water.

It is desirable that dehydration in the dehydration section 52 be carried out so that the moisture content at the thermal flow temperature is 1% or less. In this way, molded products made using resin composite products with a moisture content controlled below a certain level will not suffer from molding defects due to water foaming, etc.

In this embodiment, in addition to pellets, various resin composite products listed below can be produced from the molten kneaded material 36 removed from the extruder 30.

Products for underground burial, products with a density of 1.5 g/cm3 or ^more , flat yarn, products used for storage or transportation, bags or boxes used for packaging or delivery, products whose resin is polyolefin and has flame retardancy with an oxygen index of 26 or more, products whose resin is polyvinyl chloride and is used for building materials or civil engineering purposes, products whose resin is polystyrene or polyolefin and is microwave-safe, and products whose resin is polyethylene and is used for frozen foods.

The above-mentioned products having a density of 1.5 g/cm ^or more have excellent injection moldability because the fluidity of the molten kneaded body 36 is not easily reduced even when the fly ash 25a is heavily filled. This makes it possible to take advantage of the high density and manufacture resin composite products such as weights used at construction sites.

Until now, it has been thought impossible to use resin composite materials containing fillers in the flat yarn products mentioned above. However, by incorporating recycled powders such as pre-made ash, it is possible to provide flat yarns using resin composite materials with performance that is fully suitable for practical use.

In addition, resin composite products with a synthetic resin content of less than 50% are considered non-plastic products, which can provide incentives for their active use. Furthermore, resin composite products containing clinker ash as a filler have excellent rigidity and buckling strength, making them suitable for resin composite products such as the corrugated pipes needed for undergrounding electric cables. They also exhibit sufficient rigidity when using LLDPE, LDPE, or recycled resins of these materials as the matrix.

In addition, resin composite products containing gypsum, especially when polyvinyl chloride is used as the synthetic resin 29, can be made highly flame-retardant. This makes them suitable for building materials and civil engineering applications. Gypsum, a metal sulfate 27 produced by desulfurizing combustion flue gas 24 in thermal power plants 10, is highly safe and has a high degree of whiteness, making it suitable for food applications. Furthermore, because gypsum contains a large amount of bound water, it is highly heat-resistant, making it suitable for use in microwave ovens. In particular, when polyethylene is used as the synthetic resin 29, it is suitable for use in resin composite products for frozen foods. Furthermore, when a polyhydric alcohol is used as a liquid medium during the heating and kneading process of the molten kneaded body 36, the adhering water, which functions as a plasticizer, can be more effectively removed, resulting in a resin composite product suitable for frozen foods.

Furthermore, when these resin composite products are incinerated, the amount of carbon dioxide generated by the synthetic resin 29 equivalent to the amount of recycled powder 28 (pre-formed ash 26, metal sulfate 27) filled in them can be considered to have reduced emissions. For this reason, the amount of carbon dioxide emission reduction can be set according to the amount of recycled powder 28 filled in, and this can be attached to the resin composite product as a point where separation and storage are possible.

As a result, the more a product with a higher blend ratio of recycled powder 28 is used, the more points will be accumulated for its carbon dioxide emission reduction performance. This provides an incentive for users of resin composite products to use resin composite products with a higher blend ratio, and for manufacturers to actively develop resin composite products with a higher blend ratio.

In this way, by effectively utilizing the existing ash 26 and/or metal sulfate 27 (gypsum) produced by flue gas desulfurization, which are buried in large quantities in dedicated disposal sites 20, as fillers for resin composite products, it is possible to reduce greenhouse gases released into the environment and make a significant contribution to preventing global warming.

The manufacturing method for resin composite products according to the embodiment described above allows for the reuse of buried pre-made ash 26, which leads to the extension of the life of the dedicated coal ash disposal site 20 currently in operation. Furthermore, because pre-made ash 26 is already stocked in large quantities at the dedicated disposal site 20, shipments can be flexibly adjusted according to demand. Furthermore, by dispersing and compounding pre-made ash 26 and metal sulfates 27, which are by-products of thermal power generation 10, into synthetic resin 29 as fillers, the amount of synthetic resin 29 produced from fossil resources can be reduced, leading to the development of a resin composite product that contributes to the realization of the SDGs.

10... Coal-fired power generation, 11... Boiler, 12... Turbine, 13... Generator, 14... Electrostatic precipitator, 15... Chimney, 16a, 16a ₁ , 16a ₂ , 16b... Silo, 17... Clinker hopper, 18... Dehydration tank, 20... Dedicated disposal site, 21... Classifier, 22... Flue gas desulfurizer, 23... Tank, 24... Combustion flue gas, 25... Coal ash, 25a... Fly ash, 25b... Clinker ash, 26... Pre-formed ash, 27... Metal sulfate, 28... Recycled powder, 29... Synthetic resin, 30 (30A, 30B)... Extruder, 31... Feeding section, 32... Drive unit, 33...cylinder, 34...vent unit, 35...die unit, 36...molten kneaded body, 37...liquid medium, 38...trap, 39...vacuum pump, 40 (40A, 40B)...raw material supply unit, 41...adjustment unit, 42...mixing tank, 43...mixture, 45...resin container, 46...supply unit, 48...dispersion body, 50 (50A, 50B)...manufacturing apparatus, 51...open valve, 52...dehydration unit, 55...outlet.

Claims (5)

A process of collecting coal ash, which is a residue of coal combustion in thermal power generation, by burying it at a dedicated disposal site and generating ash ;
A step of adjusting at least one of the particle size, composition, and moisture content of the recovered ash to make it into a recycled powder;
A method for producing a resin composite product , comprising: a step of heating and kneading the mixture of the recycled powder and the synthetic resin at a temperature at which the synthetic resin melts, and removing the molten kneaded mixture;
A method for manufacturing a resin composite product, in which the recycled powder is further blended with a dispersion in which at least one of layered silicate, polysaccharide nanofiber, and hydrophilic cellulose derivative is dispersed in water or a polyhydric alcohol to form the mixture . The method for producing a resin composite product according to claim 1 ,
A method for producing a resin composite product, comprising the step of dehydrating the molten kneaded body at a set pressure higher than atmospheric pressure in a dehydration section provided above the outlet of the molten kneaded body. The method for producing a resin composite product according to claim 1 ,
In the step of preparing the regenerated powder,
The method for producing a resin composite product further comprises blending the coal ash or incineration ash from a combustion facility that has been stored without being buried. The method for producing a resin composite product according to claim 1 ,
The coal ash is at least one of clinker ash and fly ash. The method for producing a resin composite product according to claim 1 ,
The method for producing a resin composite product comprises converting the removed molten kneaded product into pellets, a molded product, or a molded product via the pellets.