Formed coal and method for producing formed coal

Abstract

This formed coal contains a carbide of a bio-derived renewable resource, and is characterized in that: the ratio of the cumulative pore volume of pores having a pore diameter range of 2-1000 μm to the total pore volume is 60 vol.% or less; and the ratio of the cumulative specific surface area in pores having a pore diameter range of 0.001-0.200 μm to the total cumulative specific surface area in all the pores is 60-90%.

Description

Molded coal and method for manufacturing molded coal

[0001] This invention relates to molded charcoal and a method for producing molded charcoal.

[0002] Traditionally, various melting furnaces such as blast furnaces, cupola furnaces, and shaft-type gasification and melting furnaces have used coke, which is produced by carbonizing coal to increase its carbon concentration, as a heat source.

[0003] The above-mentioned cupola is a vertical melting furnace used to melt ingots (pig iron, steel scrap, cast iron scrap, etc.) to produce cast iron, and is used to produce cast iron, which is a raw material for automobile parts, etc. As shown in Figure 1, in the melting furnace F, in addition to coke, ingots and slag-forming agents (limestone) are sequentially introduced from the top of the furnace, so that a bed coke layer BC, an ingot layer I, and a slag-forming agent layer L are sequentially stacked in the melting zone of the melting furnace, and above that, a desired number of stacks consisting of coke layers C, ingot layers I, and slag-forming agent layers L, which are further introduced sequentially, are arranged.

[0004] During the production of cast iron, air or oxygen is blown in from tuyeres T attached to the lower part of the melting zone to burn the coke constituting the bed coke layer BC while melting the metal constituting the base metal layer I. Impurities are discharged as slag S and the metal is refined. Molten iron FE is then obtained from the tap port E located at the bottom of the melting furnace F, and subsequently cast into the desired shape using a mold. When the bed coke layer BC, base metal layer I, and slag-forming layer L located in the melting zone are burned or melted in the melting furnace F, the laminate consisting of the coke layer C, base metal layer I, and slag-forming layer L located in the upper part of the melting zone sequentially reaches the melting zone and is similarly subjected to the metal melting process. Therefore, by sequentially introducing the coke layer C, base metal layer I, and slag-forming layer L into the melting furnace F, a continuous metal melting process is made possible.

[0005] Incidentally, in recent years, with the growing awareness of the environment, biomass, a renewable resource derived from living organisms, has been attracting attention from the perspective of so-called carbon neutrality. Since coke, mentioned above, also generates a large amount of carbon dioxide when burned, it is conceivable to use biomass as a substitute for coke.

[0006] From this perspective, Patent Document 1 proposes a biomass molded product manufactured by a method comprising: a semi-carbonization step of heating woody biomass to 200°C or more and 330°C or less in an atmosphere where oxygen supply is cut off to obtain semi-carbonized material; a semi-carbonized material grinding step of grinding the semi-carbonized material to a particle size of 300 μm or less to obtain semi-carbonized material powder; and a molding step of heating the semi-carbonized material powder to a temperature in the range of 125°C or more and 300°C or less, and then pressurizing it to 100 MPa or more and 300 MPa or less to mold the semi-carbonized material powder and obtain a molded product.

[0007] Japanese Patent Publication No. 2024-25560

[0008] On the other hand, the inventors found that using conventionally proposed biomass molded products as a substitute for coke presents the following problems.

[0009] In other words, as explained using Figure 1, the coke used in the cupola (coke for foundrying) is required to be permeable when forming the bed coke layer BC and coke layer C in order to discharge the gas generated in the melting furnace F from the top of the melting furnace F, and also permeable when forming the bed coke layer BC and coke layer C in order to discharge the molten iron generated in the melting furnace F from the bottom of the melting furnace F. In other words, the coke used in the cupola is required to function as a spacer in the melting furnace F and be able to form passages for the gas and molten iron mentioned above.

[0010] However, the inventors found that when using biomass molded products, as previously proposed in Patent Document 1, etc., as a substitute for the above-mentioned coke, they lacked sufficient strength and were pulverized by the weight of the base metal, slag-forming agent, and the biomass molded product itself that accumulated in the melting furnace, making it difficult to ensure breathability and liquid permeability.

[0011] Figure 2 shows a scanning electron microscope (SEM) image of woody biomass char (cedar char) proposed in Patent Document 1. As shown in Figure 2, in woody biomass char, volatile components contained in the biomass are removed by heat treatment, forming cavities. According to the inventors' research, these cavities make it difficult to achieve sufficient strength when used as a substitute for coke.

[0012] Patent Document 1 proposes a method for improving the strength of a biomass molded product by granulating the semi-carbonized biomass and densifying the physical structure inside the biomass molded product. Therefore, it is conceivable that increasing the density of molded charcoal would improve its strength. However, the present inventors have found that simply densifying the physical structure inside the molded product by granulating the semi-carbonized biomass by increasing the density of the molded product does not necessarily yield the desired strength.

[0013] Furthermore, it was found that when biomass molded products, as conventionally proposed in Patent Document 1, etc., are used as a substitute for coke in cupolas, they do not exhibit the same level of flammability as coke due to differences in reactivity with oxygen.

[0014] The coke used in the cupola is first subjected to oxygen (O) blown in from the tuyer T (shown in Figure 1), as shown in the following reaction equation (1). ２ ) reacts with coke (C) that makes up the bed coke layer BC to produce carbon dioxide (CO2). ２ ) generates a large amount of heat. C + O ２ =CO ２ +409.19 kJ (1) Next, the carbon dioxide (CO) generated by equation (1) ２ As shown in the following reaction equation (2), the ) rises within the melting furnace F and comes into contact with coke (C), generating carbon monoxide (CO). ２ +C = 2CO - 156.48kJ (2) The carbon monoxide (CO) generated in equation (2) is reacted with the oxygen (O) in the furnace as shown in the following reaction equation (3). ２), combines with carbon dioxide (CO ２ ) to produce carbon dioxide, which is discharged from the upper part of the furnace to the outside of the furnace by the upward airflow generated in the melting furnace. 2CO + O ２ = 2CO ２ + 565.68 kJ (3)

[0015] Here, the heat generated in the reaction formula (1) that is the starting point of the chemical reaction is involved in the preheating, melting, and superheating of the metal placed in the melting furnace F, the slagging of impurities, the reduction of oxides, etc. Therefore, the reactivity of the coke used in the cupola with oxygen is extremely important, especially in the reaction formula (1).

[0016] However, as a result of investigations by the present inventors, the biomass formed body with a densified physical structure inside the formed body proposed in Patent Document 1 is difficult to react with oxygen in the cupola, leading to a decrease in the calorific value, a decrease in the temperature inside the cupola, a deterioration in the quality of cast iron associated therewith, and a complication of the manufacturing conditions due to the inability to charge various raw materials from the furnace top at a predetermined ratio and time interval, etc. It has been found that this occurs.

[0017] Under such circumstances, an object of the present invention is to provide a formed carbon containing a carbide of a bio-derived renewable resource that has a high strength capable of ensuring air permeability and liquid permeability even when used as a substitute for coke in a cupola, and has a reactivity with oxygen comparable to that of coke, and to provide a method for manufacturing the formed carbon containing a carbide of a bio-derived renewable resource.

[0018] As a result of intensive investigations by the present inventors to solve the above technical problems, the ratio of the integrated pore volume of pores with a pore diameter range of 2 μm or more and 1000 μm or less to the total pore volume is 60% by volume or less, and the ratio of the integrated specific surface area inside the pores of pores with a pore diameter range of 0.001 μm or more and 0.200 μm or less to the integrated specific surface area of all pores is 60% or more and 90% or less. It has been found that the above problems can be solved by a formed carbon containing a carbide of a bio-derived renewable resource, and based on this finding, the present invention has been completed.

[0019] In other words, the present invention relates to: (1) molded charcoal containing bio-derived renewable resource char, wherein the ratio of the cumulative pore volume in pores with a pore diameter range of 2 μm to 1000 μm to the total pore volume is 60 volume% or less, and the ratio of the cumulative specific surface area in pores with a pore diameter range of 0.001 μm to 0.200 μm to the cumulative specific surface area in all pores is 60% to 90%; (2) molded charcoal according to (1) above, wherein the cold compressive strength is 20 MPa or more; (3) molded charcoal according to (1) or (2) above, wherein the porosity is 15 to 60 volume%; (4) a method for producing molded charcoal according to (1) above, comprising: a mixing step of mixing bio-derived renewable resource charcoal with a binder; a molding step of molding the mixture obtained in the mixing step; and a heat treatment step of heat treating the molded product obtained in the molding step, wherein in the heat treatment step, the following formula (I) {(D １ -D ２ ) / D １} × 100 (I) (However, D １ This is the bulk density (g / cm³) of the molded product obtained in the molding process. ３ ) and D ２ This is the bulk density (g / cm³) of the heat-treated product obtained in the heat treatment process. ３ (5) The present invention provides a method for producing molded charcoal as described in (4) above, wherein the molding pressure in the molding step is 20 to 200 MPa and the molding time is 0.5 seconds to 60 minutes.

[0020] According to the present invention, it is possible to provide molded charcoal containing bio-derived renewable resource charcoal that has high strength to ensure permeability and liquid permeability even when used as a substitute for coke in a cupola, and has a reactivity with oxygen equivalent to that of coke, and to provide a method for producing molded charcoal containing bio-derived renewable resource charcoal.

[0021] This is a schematic cross-sectional view showing the structure inside the cupola. This is a scanning electron microscope (SEM) image showing that carbonized wood (Japanese cedar), a type of biomass, contains many cavities. This figure shows the relationship between pore diameter and pore volume in the molded charcoal obtained in the examples and comparative examples of the present invention. This figure shows the relationship between pore diameter and the ratio of the cumulative pore volume to the total pore volume (cumulative pore volume ratio) in the molded charcoal obtained in the examples and comparative examples of the present invention. This figure shows the relationship between pore diameter and the specific surface area within the pores in the molded charcoal obtained in the examples and comparative examples of the present invention. This figure shows the relationship between pore diameter and the ratio of the cumulative specific surface area within the pores to the cumulative specific surface area within the total pores (cumulative specific surface area ratio within the pores) in the molded charcoal obtained in the examples and comparative examples of the present invention.

[0022] First, the molded charcoal according to the present invention will be described. The molded charcoal according to the present invention is a molded charcoal containing carbonized material from bio-derived renewable resources, characterized in that the ratio of the cumulative pore volume in pores with a pore diameter range of 2 μm to 1000 μm to the total pore volume is 60% by volume or less, and the ratio of the cumulative specific surface area in pores with a pore diameter range of 0.001 μm to 0.200 μm to the cumulative specific surface area in all pores is 60% to 90%.

[0023] The bio-derived renewable resource charred material contained in the molded charcoal according to the present invention is a material obtained by carbonizing biomass (biomass charred material) and means a material that is solid at 20°C and 1 atm.

[0024] Furthermore, in the molded charcoal according to the present invention, the biomass that forms the carbonized material of bio-derived renewable resources refers to bio-derived resources other than fossil fuels.

[0025] In the molded charcoal according to the present invention, the biomass that forms carbonized biomass from renewable resources of biological origin includes one or more types of biomass that produce carbonized biomass through thermal decomposition, such as forestry biomass, agricultural biomass, livestock biomass, fishery biomass, and waste biomass.

[0026] In the molded charcoal according to the present invention, forestry biomass is preferred as the biomass that forms the carbonized material of bio-derived renewable resources, and woody biomass is a specific example of forestry biomass. Woody biomass can include one or more types of wood selected from cedar, cypress, pine, chestnut, oak, willow, acacia, poplar, pine, eucalyptus, etc. Papermaking by-products such as pulp black liquor and chip dust obtained from these types of wood, sawmilling by-products such as bark and sawdust, thinned wood, forest residues such as branches, leaves, tops, and scraps, and spent logs for edible fungi may also be selected from one or more types of woody general waste such as pruned branches from street trees of the national, prefectural, or municipal governments, or garden trees of private homes, or woody industrial waste such as pruned branches from garden trees of companies, or construction waste. Among woody biomass, coniferous trees are preferred, and Japanese cedar (Cryptomeria japonica) is even more preferred, due to their large domestic distribution volume and low impurity content.

[0027] In the molded charcoal according to the present invention, the method for producing carbonized bio-derived renewable resources by carbonizing biomass is not particularly limited and can be appropriately selected from known methods. For example, it can be produced by sequentially applying (1) a crushing step, (2) a carbonization step, and optionally a further (3) a pulverization step to the biomass (hereinafter referred to as method a for producing carbonized bio-derived renewable resources). The method a for producing carbonized bio-derived renewable resources will be described below.

[0028] (1) Crushing process In method a for producing carbonized biomass from renewable resources, (1) the crushing process is a process of crushing biomass to facilitate transportation and carbonization. The dimensions of the crushed biomass can be appropriately selected from the viewpoint of the cost and efficiency of the crushing process and the carbonization efficiency of the biomass in the subsequent carbonization process.

[0029] In this application, the dimensions of the biomass and the dimensions of the biomass charred material refer to the length of the longest part that represents the maximum dimension.

[0030] In method a for producing bio-derived renewable resources, (1) the crushing of biomass in the crushing step can be carried out using a known crusher, and examples of crushers include one or more selected from single-shaft crushers, multi-shaft crushers, hammer crushers, chain crushers, chippers, etc.

[0031] In method a for producing carbonized bio-based renewable resources, (1) it is desirable that the biomass used in the crushing process be pre-dried. In method a for producing carbonized bio-based renewable resources, (1) pre-dried biomass used in the crushing process can further improve the crushing efficiency in the biomass crushing process. One or more methods for drying the biomass can be selected from methods such as natural drying by exposure to the elements outdoors or heat drying using a dryer.

[0032] The biomass after drying is preferably 30% by mass or less, and more preferably 15% by mass or less. Furthermore, considering the cost and time required for drying, the biomass after drying is preferably 1% by mass or more.

[0033] In this application, the moisture content is measured in accordance with JIS M 8812:2006, and refers to the value calculated by measuring the mass loss of the sample before and after drying at 200°C, i.e., the moisture content on a dry basis. For example, the moisture content of biomass is calculated by the following formula: Moisture content (mass%) = {(Mass of biomass before drying (kg) - Mass of biomass after drying (kg)) / Mass of biomass before drying (kg)} × 100

[0034] (2) Carbonization process In method a of producing carbonized bio-derived renewable resources, (2) carbonization process is a process of carbonizing the biomass crushed in the crushing process described above in (1) in a carbonization furnace to obtain a biomass carbonized body. Here, biomass carbonization means a process in which biomass containing organic matter is thermally decomposed at a predetermined temperature to produce a solid material with a high carbon content and high heat per unit mass, i.e., a carbonized body.

[0035] Examples of carbonization furnaces used in the biomass carbonization process include one or more selected from electric furnaces, externally heated rotary kilns, internal combustion rotary kilns, fluidized bed heating furnaces, screw heating furnaces, shaft furnaces, and carbonization furnaces. From the viewpoint of productivity, it is preferable that the carbonization furnace be a continuous carbonization apparatus in which a transport conveyor is connected to the carbonization apparatus body and biomass is automatically fed into the carbonization apparatus body.

[0036] (2) The temperature at which biomass is carbonized in the carbonization process (carbonization temperature) is preferably 300°C to 1200°C, more preferably 350°C to 950°C, and even more preferably 400°C to 650°C. (2) By setting the temperature at which biomass is carbonized in the carbonization process to be above the lower limit, moisture and volatile matter contained in the biomass can be removed more effectively, and even if cavities with a pore diameter of several μm occur, the penetration of the binder during the production of molded charcoal can be made easier, making it easier to seal the generated cavities or to control the size of the cavities to be smaller. In addition, the hardness tends to increase as the carbonization of the biomass progresses, making it easier to increase the strength of the molded charcoal. By setting the temperature at which biomass is carbonized to be below the upper limit, moisture and volatile matter contained in the biomass can be removed more effectively while suppressing the energy and cost required for carbonization, and the yield of the resulting biomass carbonized material can be improved more easily.

[0037] (2) When raising the biomass to the carbonization temperature in the carbonization process, the heating rate is preferably 1°C / min to 200°C / min. By keeping the heating rate within the above range, it is possible to further suppress the granulation caused by unintended rupture due to rapid heating, improve productivity, and more easily reduce manufacturing costs.

[0038] The carbonization time is preferably 1 minute to 120 minutes, more preferably 5 minutes to 90 minutes, and even more preferably 10 minutes to 60 minutes. By having the biomass carbonization time within the above range, the biomass can be thermally decomposed in a shorter time, thereby further reducing manufacturing costs, improving productivity, and enabling uniform and easy carbonization throughout. In this application, carbonization time refers to the time from the moment the carbonization temperature is reached until that temperature is maintained.

[0039] (2) When cooling down the carbonized biomass after the carbonization process is completed, the cooling rate is preferably 1°C / min to 200°C / min. By cooling down the carbonized biomass within the above range, it is possible to more easily improve productivity while suppressing the formation of pores due to crack formation in the carbonized biomass by rapid cooling.

[0040] (2) The oxygen concentration in the atmosphere during the carbonization process is preferably 10% by volume or less, more preferably 5% by volume or less, and even more preferably 2% by volume or less, taking into account the consumption of biomass due to oxidation.

[0041] (2) The carbonization process is carried out in a container that forms a space in which the inflow of air is obstructed, for example, in order to reduce the oxygen concentration. If necessary, an inert gas such as nitrogen or argon may be circulated in the container, or oxygen may be discharged from the container using a vacuum pump.

[0042] (2) The moisture content of the biomass carbonized material obtained in the carbonization process is preferably 10% by mass or less, more preferably 6% by mass or less, and even more preferably 3% by mass or less, on a dry basis. (2) By having a moisture content of the biomass carbonized material obtained in the carbonization process that is below the above value, expansion and bursting during the heat treatment process when forming molded charcoal can be suppressed, thereby suppressing a decrease in yield.

[0043] (2) The lower limit of the moisture content of the biomass carbonized material obtained in the carbonization process is not particularly limited, but it is preferably 0.1% by mass or more. (2) By having a moisture content of 0.1% by mass or more of the biomass carbonized material obtained in the carbonization process, the moisture content can be easily controlled to a more appropriate range while further reducing the costs associated with drying and moisture protection.

[0044] (2) The volatile content of the biomass carbonized material obtained in the carbonization process is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, and even more preferably 5 to 20% by mass. (2) By having the volatile content of the biomass carbonized material obtained in the carbonization process within the above range, it is possible to suppress the energy cost required to reduce volatile content while suppressing expansion and bursting during the heat treatment process when forming the molded charcoal, thereby suppressing a decrease in yield.

[0045] In this application, the volatile content percentage refers to the value calculated by measuring the mass loss from room temperature to 1000°C under the conditions of a heating rate of 10°C / min and a nitrogen gas flow rate of 1.0 L / min.

[0046] (2) If the dimensions of the biomass carbonized material obtained in the carbonization process are between 10 and 5000 μm, the biomass carbonized material obtained through the above carbonization process shall be used as the carbonized material of the bio-derived renewable resource intended for that purpose. Furthermore, if the dimensions of the biomass carbonized material obtained in the carbonization process (2) exceed 5000 μm, the crushing process described in (3) below shall be carried out in addition.

[0047] (3) Crushing step In method a for producing bio-derived renewable resource carbon, (3) the crushing step is a step of crushing the biomass carbonized material obtained in the biomass carbonization step to obtain bio-derived renewable resource carbon. (2) The apparatus for crushing the biomass carbonized material obtained in the carbonization step is not particularly limited, but one or more can be selected from counter jet mills, swirling airflow jet mills, impact high-speed mills, hammer mills, Nara-type free crushers, ball mills, general-purpose cutter mills, fine cutter mills, crushing rotary mills, etc. Multiple crushing devices may be used in combination to efficiently obtain bio-derived renewable resource carbon of a desired size.

[0048] The particle size of the bio-derived renewable resource char obtained by crushing biomass char is preferably 10 to 5000 μm, more preferably 20 to 4000 μm, even more preferably 30 to 3000 μm, even more preferably 30 to 1000 μm, particularly preferably 40 to 500 μm, even more preferably 40 to 300 μm, even more preferably 40 to 200 μm, and especially preferably 40 to 100 μm.

[0049] By ensuring that the particle size of the bio-derived renewable resource char obtained by crushing biomass char is above the above lower limit, an excessive increase in specific surface area can be suppressed, and the adsorption of moisture, gases, etc., onto the surface of the bio-derived renewable resource char can be further suppressed. This effectively suppresses the decrease in strength caused by the volatilization of these substances during the formation of molded charcoal and the formation of pores.

[0050] Because the particle size of the bio-derived renewable resource char is below the above upper limit, the bio-derived renewable resource char has a moderately fine particle size range, which makes it easier for the physical structure of the molded charcoal according to the present invention to become dense and homogeneous, thus making it easier to improve its strength.

[0051] In this application, unless otherwise specified, the particle size of bio-derived renewable resource carbides refers to the maximum particle size and is the value measured in accordance with JIS Z 8825:2013.

[0052] (3) In the crushing process, the moisture content of the bio-derived renewable resource char obtained by crushing the biomass char is preferably 10% by mass or less, more preferably 6% by mass or less, even more preferably 4% by mass or less, and even more preferably 3% by mass or less, on a dry basis. By keeping the moisture content of the bio-derived renewable resource char below the above values, expansion and bursting during the heat treatment process when forming molded char can be suppressed, thereby further suppressing the decrease in yield.

[0053] There is no particular lower limit to the moisture content of bio-derived renewable resource char, but it is preferable that it be 0.1% by mass or more on a dry basis. By having a moisture content of 0.1% by mass or more of bio-derived renewable resource char, the moisture content can be more easily controlled within an appropriate range while further reducing the costs associated with drying and moisture protection.

[0054] The volatile content of bio-derived renewable resource char is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, and even more preferably 5 to 20% by mass. By having the volatile content of bio-derived renewable resource char within the above range, it is possible to further suppress the energy cost required to reduce volatile content while suppressing expansion and rupture during the heat treatment process when forming molded char, thereby further suppressing the decrease in yield.

[0055] In method a for producing bio-derived renewable resource char, in order to control the moisture content and volatile matter of the bio-derived renewable resource char obtained in step (3), a drying step or heat treatment step may be performed after step (3) as needed.

[0056] The molded charcoal according to the present invention preferably contains 50 to 95% by mass of bio-derived renewable resource char, more preferably 55 to 95% by mass, and even more preferably 60 to 95% by mass.

[0057] The molded charcoal according to the present invention has a content ratio of bio-derived renewable resource charred material within the above range, thereby enabling effective utilization of bio-derived renewable resource charred material to achieve carbon neutrality, and also allowing for easy expression of desired strength and reactivity with oxygen.

[0058] In the shaped charcoal according to the present invention, the content ratio of bio-derived renewable resource char is calculated from the mass of the shaped charcoal, the mass of bio-derived renewable resource char, and the volatile content ratio (mass%) of the bio-derived renewable resource char using the following formula: Content ratio (mass%) of bio-derived renewable resource char = [Mass of bio-derived renewable resource char (kg) × {(100 - Volatile content ratio (mass%) of bio-derived renewable resource char (mass%)) / 100} / Mass of shaped charcoal (kg)] × 100

[0059] The molded charcoal according to the present invention may contain carbon materials other than carbides of bio-derived renewable resources. Examples of carbon materials other than carbides of bio-derived renewable resources include graphite, coal, coke, carbon black, carbon nanotubes, carbon nanofibers, carbon fibers, carbides of chemical fibers, carbides of plastics, carbides of tires, and carbon materials produced from carbon monoxide, carbon dioxide, or hydrocarbons. Furthermore, from the viewpoint of achieving a more appropriate pore distribution, the coal content relative to the total carbon material is preferably 3.0% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less. More specifically, since coal does not have many pores, if the carbon material contains coal in an amount exceeding the above upper limit, it becomes difficult to adjust the pore distribution to an appropriate range, and the resulting molded charcoal tends to have reduced strength, permeability, and liquid permeability.

[0060] When the molded charcoal according to the present invention contains carbon materials other than carbides of bio-derived renewable resources, the molded charcoal according to the present invention preferably contains 0.1 to 70.0 parts by mass of carbon materials other than carbides of bio-derived renewable resources, more preferably 0.1 to 50.0 parts by mass, even more preferably 0.1 to 30.0 parts by mass, and particularly preferably 0.1 to 10.0 parts by mass, of 100 parts by mass of carbides of bio-derived renewable resources. In the molded charcoal according to the present invention, by having the content range of carbon materials other than carbides of bio-derived renewable resources within the above range, it is possible to contain a desired amount of carbides of bio-derived renewable resources and suitably achieve carbon neutrality.

[0061] The molded charcoal according to the present invention preferably contains a binder heat-treated product.

[0062] In the molded charcoal according to the present invention, the binder constituting the binder heat-treated product may be an organic binder derived from biomass, or an organic binder excluding biomass, but a biomass-derived organic binder is preferred from the viewpoint of achieving carbon neutrality. When the molded charcoal according to the present invention is formed, the organic binder penetrates into the cavities of the biomass and carbonizes, making it easier to control the volume and specific surface area of ​​the pores constituting the biomass.

[0063] In the molded charcoal according to the present invention, the binder is a binding agent for bonding substances together. When the binder constituting the heat-treated binder is an organic binder, the organic binder can be one or more selected from tar pitch, phenolic resin, lignin, kraft lignin, sodium lignin sulfonate, monosaccharides (glucose, fructose, galactose, etc.), disaccharides (maltose, sucrose, lactose, oligosaccharides, etc.), polysaccharides (dextrin, starch, cellulose, glycogen, etc.), black liquor, lignin-modified phenolic resin, plant-derived tar, vegetable oil, rosin resin, furan resin, etc. In particular, from the viewpoint of further improving binding properties and achieving a more appropriate pore distribution, the organic binder preferably contains one or more selected from the group consisting of monosaccharides, disaccharides, and polysaccharides, more preferably contains one or more selected from the group consisting of fructose and glucose, and even more preferably contains fructose. Furthermore, fructose has high solubility in water, and a high-concentration binder aqueous solution can be prepared with a small amount of water, thus further suppressing the introduction of moisture into the molded charcoal. As a result, crack formation (explosion) due to the vaporization of moisture during the heat treatment process can be further reduced, and the yield can be further improved. For this reason, it is even more preferable for the organic binder to contain fructose. In addition, coal tar pitch (the residue obtained when coal tar is fractionally distilled) can be mentioned as one of the tar pitches mentioned above. When emphasizing the importance of achieving a more appropriate pore distribution, the content of coal tar pitch relative to the total organic binder is preferably 3.0% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less.

[0064] In the molded charcoal according to the present invention, if the binder constituting the binder heat-treated product is an organic binder, the binder is carbonized by the heat treatment. In the molded charcoal according to the present invention, if the binder constituting the binder heat-treated product is an organic binder, it is preferable that the residual carbon content of the organic binder is 10% by mass or more and 80% by mass or less, more preferably 15% by mass or more and 75% by mass or less, even more preferably 20% by mass or more and 70% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less. In the molded charcoal according to the present invention, the residual carbon content of the organic binder and viscosity are correlated. Organic binders with a low residual carbon content have low viscosity and easily penetrate into the cavities of bio-derived renewable resource carbonized material, but the proportion that is carbonized in the heat treatment process described later is low. On the other hand, organic binders with a high residual carbon content have high viscosity, making it difficult to mix with bio-derived renewable resource carbonized material in order to mold the molded charcoal. In the molded charcoal according to the present invention, the residual charcoal rate of the organic binder constituting the binder heat-treated product is within the above range. Therefore, when mixed with carbonized material from bio-derived renewable resources to form the molded charcoal according to the present invention, it penetrates appropriately into the cavities of the carbonized material from bio-derived renewable resources to form molded charcoal having a desired porosity distribution, and mixing can be performed more efficiently in the mixing process.

[0065] In this application, the carbon residue rate of the binder is determined from the change in mass of the binder when it is heated from room temperature to 1000°C at a heating rate of 10°C / min and a nitrogen gas flow rate of 1.0 L / min, and the total mass of the organic binder before heat treatment is W. Ａ (g) The mass of the organic binder after heat treatment is W Ｃ When (g) is used, the residual carbon percentage (mass%) = (W Ｃ / W Ａ This refers to the value calculated by multiplying by ) × 100.

[0066] The molded charcoal according to the present invention preferably contains a binder heat-treated material content of 5 to 50% by mass, more preferably 5 to 45% by mass, and even more preferably 5 to 40% by mass, relative to the total amount of molded charcoal. In the molded charcoal according to the present invention, the binder heat-treated material content is determined from the mass of the molded charcoal, the mass of the binder, and the residual charcoal rate of the binder (mass%) using the following formula: Binder heat-treated material content (mass%) = {Binder mass (kg) × (Binder residual charcoal rate (mass%) / 100) / Molded charcoal mass (kg)} × 100

[0067] In the molded charcoal according to the present invention, by having the content ratio of the heat-treated binder within the above range, the resulting molded charcoal can easily exhibit higher strength, and the decrease in productivity, such as the binder seeping out of the mixture during the production of the molded charcoal making it difficult to transport, can be more easily suppressed.

[0068] The molded charcoal according to the present invention has a ratio of 60 volume% or less of the cumulative pore volume of pores with a diameter range of 2 μm to 1000 μm to the total pore volume. This makes it possible to easily exhibit high strength that suppresses collapse due to the weight of the deposit in the melting furnace and ensures air permeability and liquid permeability. From the viewpoint of more reliably exhibiting this effect, it is preferably 1 to 60 volume%, more preferably 3 to 55 volume%, even more preferably 5 to 50 volume%, even more preferably 10 to 45 volume%, and particularly preferably 15 to 40 volume%. Furthermore, the molded charcoal according to the present invention has a ratio of 60 volume% or less of the cumulative pore volume of pores with a diameter range of 2 μm to 1000 μm to the total pore volume, preferably 55 volume% or less, more preferably 50 volume%, even more preferably 45 volume%, and particularly preferably 40 volume%. Furthermore, in the molded charcoal according to the present invention, the ratio of the cumulative pore volume in pores with a pore diameter range of 2 μm to 1000 μm to the total pore volume is preferably 1 volume% or more, more preferably 3 volume% or more, even more preferably 5 volume% or more, even more preferably 10 volume% or more, and particularly preferably 15 volume% or more.

[0069] In the molded charcoal according to the present invention, the ratio of the cumulative pore volume in pores with a diameter range of 2 μm to 1000 μm to the total pore volume (volume %) refers to the value calculated by the following formula: Ratio of the cumulative pore volume in pores with a diameter range of 2 μm to 1000 μm to the total pore volume (volume %) = (Cumulative pore volume in pores with a diameter range of 2 μm to 1000 μm (mL / g) / Total pore volume (mL / g)) × 100

[0070] In the molded charcoal according to the present invention, pores with a pore diameter range of 2 μm to 1000 μm originate exclusively from voids formed between the carbonized particles of bio-derived renewable resources that constitute the molded charcoal. Among the pores inherent in the molded charcoal, pores with a pore diameter range of 2 μm to 1000 μm are thought to serve as the starting point for crack formation or promote crack propagation when a load is applied to the molded charcoal, and thus strongly affect the strength of the molded charcoal.

[0071] In the molded charcoal according to the present invention, the ratio of the cumulative pore volume in pores with a diameter range of 2 μm to 1000 μm to the total pore volume is less than or equal to the above upper limit. As a result, when used as a substitute for coke, it can easily exhibit high strength that suppresses collapse due to the weight of the deposits in the melting furnace and ensures air permeability and liquid permeability.

[0072] Furthermore, in the molded charcoal according to the present invention, the ratio of the cumulative pore volume in pores with a pore diameter range of 2 μm to 1000 μm to the total pore volume is equal to or greater than the lower limit mentioned above. Therefore, when molding forming materials such as carbonized bio-derived renewable resources to produce the molded charcoal according to the present invention, molding pressure and molding time can be suppressed to prevent molding cracks, and the charcoal can be easily manufactured with high productivity.

[0073] In the molded charcoal according to the present invention, for pores with a pore diameter range of 2 μm to 1000 μm, instead of defining the range of the absolute value of the cumulative pore volume, the ratio of the cumulative pore volume in the pore diameter range of 2 μm to 1000 μm to the total pore volume can be defined, thereby making it possible to grasp the proportion of pore diameters that strongly affect the strength of the molded charcoal and to easily control the strength of the molded charcoal.

[0074] In this application, the total pore volume is a value calculated from the pore size distribution measured in accordance with JIS R 1655:2003, and represents the cumulative volume within all pores in the pore size range of 0.001 μm to 1000 μm. The total pore volume of the molded charcoal according to the present invention is preferably 0.01 to 5.00 mL / g, and more preferably 0.10 to 1.00 mL / g.

[0075] The molded charcoal according to the present invention has a ratio of 60% to 90% of the total surface area of ​​pores with a diameter range of 0.001 μm to 0.200 μm to the total surface area of ​​all pores. This allows it to easily exhibit a reactivity with oxygen equivalent to that of coke, i.e., a combustibility equivalent to that of coke, when used as a substitute for coke. From the viewpoint of more reliably exhibiting this effect, a ratio of 63% to 87% is more preferable, 65% to 85% is particularly preferable, and 70% to 85% is even more preferable. Furthermore, the molded charcoal according to the present invention has a ratio of 60% or more, preferably 63% or more, more preferably 65% ​​or more, and even more preferably 70% or more, to the total surface area of ​​pores with a diameter range of 0.001 μm to 0.200 μm. Furthermore, in the molded charcoal according to the present invention, the ratio of the cumulative specific surface area in pores with a pore diameter range of 0.001 μm to 0.200 μm to the cumulative specific surface area in all pores is 90% or less, preferably 87% or less, and more preferably 85% or less.

[0076] In the molded coal according to the present invention, by controlling the ratio of the cumulative specific surface area within pores with a pore diameter range of 0.001 μm to 0.200 μm to the cumulative specific surface area within all pores to the above range, it is possible to easily exhibit a reactivity with oxygen equivalent to that of coke, i.e., a combustibility equivalent to that of coke, when used as a substitute for coke.

[0077] In the molded charcoal according to the present invention, pores with a pore diameter range of 0.001 μm to 0.200 μm mainly originate from voids formed when water, volatile components, air, and other gases contained in the biomass and binder used as raw materials are heated, vaporized, and expanded by heat treatment during the production of the molded charcoal according to the present invention, and then discharged outside the molded charcoal. The water, volatile components, air, and other gases contained in the forming material of the molded charcoal form very elongated pores by bypassing areas with high strength in the forming material. As a result, in the resulting molded charcoal, pores with a pore diameter range of 0.001 μm to 0.200 μm have a large specific surface area within the pores, and also a large proportion of the total specific surface area of ​​all pores. A large specific surface area within the pores means an increased contact area with oxygen, making it easier to react with oxygen. Therefore, to improve reactivity with oxygen, it is sufficient to increase the cumulative specific surface area within pores with a diameter range of 0.001 μm to 0.200 μm. For this purpose, in the molded coal according to the present invention, the ratio of the cumulative specific surface area within pores with a diameter range of 0.001 μm to 0.200 μm to the total cumulative specific surface area of ​​all pores is controlled to the above range. Thus, in the molded coal according to the present invention, the pores with a diameter range of 0.001 μm to 0.200 μm play a major role in exhibiting reactivity with oxygen equivalent to that of coke.

[0078] In the molded charcoal according to the present invention, for pores with a pore diameter range of 0.001 μm to 0.200 μm, instead of defining the range of the absolute value of the cumulative specific surface area, the ratio of the cumulative specific surface area within pores with a pore diameter range of 0.001 μm to 0.200 μm to the total cumulative specific surface area within all pores can be defined. This makes it possible to grasp the proportion of specific surface area of ​​pore diameters that strongly influence the reactivity of molded charcoal with oxygen, and to easily manage the reactivity of molded charcoal with oxygen.

[0079] In this application, the cumulative specific surface area within all pores is a value calculated from the pore diameter distribution measured in accordance with JIS R 1655:2003, and refers to the cumulative specific surface area within all pores in the pore diameter range of 0.001 μm to 1000 μm. In the molded charcoal according to the present invention, the cumulative specific surface area within all pores is 1 to 100 m². ２ It is preferable that the amount be / g, and 1 to 50 m ２ It is more preferable that it be / g.

[0080] Furthermore, in this application, the ratio of the cumulative specific surface area within pores with a pore diameter range of 0.001 μm to 0.200 μm to the cumulative specific surface area within all pores is defined as the cumulative specific surface area S within all pores. ａ and the cumulative specific surface area S within pores in pores with a pore diameter range of 0.001 μm to 0.200 μm. ｂ When we sought it, (S ｂ / S ａ This refers to the value calculated by multiplying by 100.

[0081] The cold compressive strength of the molded charcoal according to the present invention is preferably 20 MPa or more, more preferably 25 MPa or more, even more preferably 30 MPa or more, particularly preferably 40 MPa or more, and even more preferably 70 MPa or more. The molded charcoal according to the present invention, by satisfying the above-mentioned cold compressive strength, can exhibit high strength that can suppress collapse due to the weight of the deposits in the melting furnace. Furthermore, from the viewpoint of improving productivity and reducing manufacturing costs, the cold compressive strength of the molded charcoal according to the present invention is preferably 200 MPa or less, more preferably 150 MPa or less, even more preferably 100 MPa or less, even more preferably 85 MPa or less, and particularly preferably 77 MPa or less. Furthermore, the cold compressive strength of the molded charcoal according to the present invention is preferably 20 MPa or more and 200 MPa or less, more preferably 25 MPa or more and 150 MPa or less, even more preferably 25 MPa or more and 100 MPa or less, even more preferably 30 MPa or more and 85 MPa or less, particularly preferably 40 MPa or more and 77 MPa or less, and even more preferably 70 MPa or more and 77 MPa or less.

[0082] In this application, cold compressive strength refers to the maximum stress value when a load is continuously applied at a compression rate of 0.2 mm / second at room temperature until the test specimen breaks.

[0083] The molded charcoal according to the present invention preferably has a porosity of 15 to 60 volume%, more preferably 20 to 55 volume%, even more preferably 25 to 50 volume%, and even more preferably 30 to 45 volume%.

[0084] By having a porosity of the molded coal according to the present invention equal to or greater than the above lower limit, it is easier to achieve the desired bulk density, and crushing due to impact when the molded coal is dropped can be further suppressed. Also, by having a porosity of the molded coal according to the present invention equal to or less than the above upper limit, it is easier to achieve the desired bulk density, and when the molded coal is fed from the top of the cupola furnace, the upward flow of the heated gas in the furnace is further suppressed, and the molded coal can be more easily stacked in a predetermined position in the furnace.

[0085] In this application, porosity is a value calculated from the pore size distribution and pore volume measured in accordance with JIS R 1655:2003, and is the total pore volume V of pores in the pore size range of 0.001 μm to 1000 μm. ｂ (mL / g), volume V of the test specimen ａ (cm ３ When measuring porosity (volume %), {total porosity volume V ｂ (mL / g) × Mass of test specimen (g) / Volume of test specimen V ａ (cm ３ This refers to the value calculated by multiplying )} by 100.

[0086] The molded charcoal according to the present invention has a bulk density of 0.7 to 1.6 g / cm³. ３ Preferably, it is 0.8 to 1.5 g / cm³. ３ It is more preferable that it be 0.9 to 1.4 g / cm³. ３ It is even more preferable if it is [this].

[0087] By having a bulk density of the molded coal according to the present invention equal to or greater than the lower limit, when the molded coal is introduced from the top of the cupola furnace, it is possible to suppress the upward movement of the molded coal due to the rising airflow of the heated gas inside the furnace, and to stack the molded coal more easily in a predetermined position inside the furnace. Furthermore, by having a bulk density of the molded coal according to the present invention equal to or less than the upper limit, it is possible to further suppress the crushing of the molded coal due to impact when it falls.

[0088] In addition, in this application document, the bulk density (g / cm³) of the molded product and molded charcoal is specified. ３ The mass (g) of the sample is measured, and each dimension of the sample is measured with a micrometer to obtain the volume (cm³).３ This refers to the value calculated from the mass and volume of the obtained sample.

[0089] In the shaped charcoal according to the present invention, the absolute value of the difference in the oxidation loss rate between the shaped charcoal and the coke for foundry is preferably 8.0 or less, more preferably 7.0 or less, even more preferably 6.0 or less, and even more preferably 5.0 or less. In the shaped charcoal according to the present invention, there is no particular limit to the lower limit of the absolute value of the difference in the oxidation loss rate between the shaped charcoal and the coke for foundry, but it may be, for example, 1.0 or more, or 2.0 or more. In the shaped charcoal according to the present invention, by having the absolute value of the difference in the oxidation loss rate between the shaped charcoal and the coke for foundry below the above upper limit, it is shown that it has the same reactivity with oxygen as commercially available coke for foundry, and productivity can be further improved by further suppressing the temperature drop in the furnace and avoiding changes in operating conditions.

[0090] The oxidation loss rate of the molded charcoal according to the present invention is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, and even more preferably 10.0% by mass or less. The oxidation loss rate of the molded charcoal according to the present invention is preferably 6.0% by mass or more, and more preferably 7.0% by mass or more. By having the oxidation loss rate of the molded charcoal according to the present invention below the above upper limit, the absolute value of the difference with the oxidation loss rate of the coke used for foundrying can be made smaller, and the amount of molded charcoal used can be further reduced. By having the oxidation loss rate of the molded charcoal according to the present invention above the above lower limit, the reactivity with oxygen can be further improved, and productivity can be further improved.

[0091] In this application, the oxidation loss rate of molded products, molded charcoal, and coke for casting can be measured by heat-treating a test piece of known mass, cut to a size of 15 mm x 15 mm x 15 mm, in an atmospheric environment by raising the temperature from room temperature to 950°C over 2 hours, then holding it at 950°C for 4 hours, cooling it, then cooling it on a metal plate for 10 minutes, and then cooling it further in a desiccator for 20 minutes, and measuring its mass to determine the mass loss rate of the sample. The obtained mass loss rate is then defined as the oxidation loss rate (mass %). In addition, commercially available coke can be used as the coke for casting.

[0092] The shaped charcoal according to the present invention preferably has a total calorific value of 7,000 to 9,000 kcal / kg, more preferably 7,200 to 8,800 kcal / kg, even more preferably 7,200 to 8,000 kcal / kg, and still more preferably 7,300 to 7,500 kcal / kg.

[0093] Because the total calorific value of the shaped coal according to the present invention falls within the above range, it is possible to exhibit a total calorific value equivalent to that of coke for casting while further suppressing thermal damage to the iron shell of the housing portion constituting the cupola.

[0094] Furthermore, the total calorific value of the molded charcoal according to the present invention refers to the value measured after the material to be measured has been crushed to a predetermined particle size, in accordance with JIS M 8814:2003.

[0095] The molded charcoal according to the present invention preferably has an ash content of 10% by mass or less, more preferably 9% by mass or less, even more preferably 8% by mass or less, and even more preferably 7.2% by mass or less. In the molded charcoal according to the present invention, having an ash content below the above upper limit allows for a further reduction in the amount of slag, which is an impurity, discharged when the molded charcoal is used, enabling the production of cast iron with high productivity. In the molded charcoal according to the present invention, there is no particular lower limit for the ash content, but the molded charcoal according to the present invention preferably has an ash content of 1% by mass or more. Having an ash content of 1% by mass or more in the molded charcoal according to the present invention allows for a further reduction in the cost of removing impurities to reduce the ash content when producing the molded charcoal according to the present invention.

[0096] In this application, the ash content is a value measured in accordance with JIS M 8812:2006, and refers to the value calculated from the mass of the sample before and after heating in an electric furnace using the following formula: Ash content (mass%) = (mass of the sample after heating in an electric furnace / mass of the sample before heating in an electric furnace) × 100

[0097] The shape of the molded charcoal according to the present invention is not particularly limited, and examples include cylindrical, cylindrical, prismatic, spherical, or shapes obtained by cutting these shapes. The size of the molded charcoal according to the present invention is not particularly limited, but for example, in the case of a cylindrical shape, examples include a diameter of 30 mm or more and 500 mm or less, preferably 40 mm or more and 400 mm or less, and a height of 20 mm or more and 600 mm or less, preferably 30 mm or more and 500 mm or less.

[0098] According to the present invention, it is possible to provide molded charcoal containing bio-derived renewable resource char, which has high strength that ensures permeability and liquid permeability even when used as a substitute for coke in a cupola, and has a reactivity with oxygen equivalent to that of coke.

[0099] Next, a method for producing molded charcoal according to the present invention will be described. The production method according to the present invention is a method for producing molded charcoal according to the present invention as described above, comprising: a mixing step of mixing carbonized material of bio-derived renewable resources with a binder; a molding step of molding the mixture obtained in the mixing step; and a heat treatment step of heat treating the molded product obtained in the molding step, wherein in the heat treatment step, the following formula (I) {(D １ -D ２ ) / D １} × 100 (I) (However, D １ This is the bulk density (g / cm³) of the molded product obtained in the molding process. ３ ) and D ２ This is the bulk density (g / cm³) of the heat-treated product obtained in the heat treatment process. ３ The method is characterized by heat treatment such that the reduction rate of bulk density calculated by ) is between 3.0% and 30.0%.

[0100] <Mixing Process> In the method for producing molded charcoal according to the present invention, in the mixing process, carbonized material from bio-derived renewable resources and a binder are mixed. Details of the carbonized material from bio-derived renewable resources and its production method in the method for producing molded charcoal according to the present invention are as described above. Details of the binder in the method for producing molded charcoal according to the present invention are also as described above.

[0101] In the method for producing molded charcoal according to the present invention, in the mixing step, a mixture is obtained by mixing carbonized material from a bio-derived renewable resource with a binder that acts as a binder.

[0102] In the method for producing molded charcoal according to the present invention, the mixing apparatus can be one or more selected from, for example, a planetary mixer, a Banbury mixer, a plunger mixer, a ribbon blender, a single-screw extruder, a twin-screw extruder, a disc mixer, a pressurized kneader, a double-arm kneader, and the like.

[0103] In the method for producing molded charcoal according to the present invention, the amount of binder mixed is preferably 10 to 200 parts by mass, more preferably 15 to 180 parts by mass, even more preferably 20 to 150 parts by mass, even more preferably 30 to 100 parts by mass, and particularly preferably 40 to 80 parts by mass, per 100 parts by mass of bio-derived renewable resource charcoal. By having the amount of binder mixed within the above range, the resulting molded charcoal can more easily exhibit high strength, and a decrease in productivity, such as the binder seeping out of the mixture during the production of molded charcoal making it difficult to transport to subsequent processes, can be more easily suppressed.

[0104] In the method for producing molded charcoal according to the present invention, carbon materials other than charcoal from bio-derived renewable resources may be mixed in the mixing step, and the carbon materials other than charcoal from bio-derived renewable resources include those mentioned above.

[0105] The temperature in the mixing process (mixing temperature) is not particularly limited, but is preferably 15 to 400°C, more preferably 20 to 380°C, and even more preferably 25 to 350°C.

[0106] In the method for producing molded charcoal according to the present invention, by keeping the mixing temperature within the above range, the viscosity of the binder can be further reduced while the binder can be thoroughly mixed and spread evenly across the surface and into the cavities of the bio-derived renewable resource charcoal.

[0107] The time in the mixing process (mixing time) can be set appropriately according to the viscosity of the mixture, preferably 1 to 120 minutes, more preferably 5 to 90 minutes, and even more preferably 10 to 60 minutes.

[0108] In the method for producing molded charcoal according to the present invention, by having the mixing time within the above range, energy loss during mixing can be further suppressed, and water, volatile components, air, and other gases incorporated into the mixture can be sufficiently discharged to the outside through mixing. Furthermore, the binder can be more thoroughly distributed to the surface and cavity of the carbonized material, which is a renewable resource of biological origin.

[0109] In the method for producing molded charcoal according to the present invention, the volume ratio in the mixing step (the ratio of the volume of the mixture containing bio-derived renewable resource char and binder to the volume in the mixing tank of the mixing apparatus) is preferably 20 to 99% by volume, more preferably 30 to 95% by volume, and even more preferably 40 to 90% by volume.

[0110] In the method for producing molded charcoal according to the present invention, by having the volume ratio in the mixing step within the above range, the mixture containing carbonized material and binder from bio-derived renewable resources can be mixed under sufficient shear force, and water, volatile components, air, and other gases contained in the mixture can be sufficiently removed to suppress the generation of pores in the molded charcoal.

[0111] In the method for producing molded charcoal according to the present invention, when calculating the volume ratio in the mixing step, the volume of the mixture shall be a value theoretically determined from the amount of each component that makes up the mixture and the true specific gravity of each component.

[0112] <Molding Process> In the method for producing molded charcoal according to the present invention, the mixture obtained in the mixing process is molded in the molding process. One molding method is to press-molde the mixture obtained in the mixing process within a mold.

[0113] As a molding apparatus for the mixture, a pressure molding apparatus is preferred, which uses mechanical compression, that is, an apparatus that contains the mixture in a space enclosed by walls such as a mold, rubber mold, or compression roll, and compresses it through these walls. More specifically, as a pressure molding apparatus, one or more types selected from presses, pelletizers, double-roll molding machines, extrusion molding machines, cold isotropic press molding machines (CIP), hot isotropic press molding machines (HIP), etc.

[0114] In the method for producing molded charcoal according to the present invention, the pressure (molding pressure) when molding the mixture in the molding process is preferably 20 to 200 MPa, more preferably 25 to 180 MPa, even more preferably 30 to 150 MPa, even more preferably 30 to 100 MPa, and particularly preferably 35 to 50 MPa.

[0115] In the method for producing molded charcoal according to the present invention, by setting the molding pressure to be above the lower limit, the binder can be more sufficiently penetrated into cavities with a diameter of several μm that exist inside or between the carbonized material of bio-derived renewable resources, thereby reducing the diameter of the cavities or eliminating them. This can also be used to more easily improve the strength of the resulting molded charcoal by increasing its density and making it more compact. In the method for producing molded charcoal according to the present invention, by setting the molding pressure to be below the upper limit, residual stress in the resulting molded charcoal can be more suppressed, and gases generated during molding can be more easily removed, thereby further suppressing cracking of the resulting molded charcoal and malfunctions of the molding equipment due to excessive load.

[0116] In the method for producing molded charcoal according to the present invention, the temperature at which the mixture is molded in the molding process (molding temperature) is preferably 15 to 400°C, more preferably 20 to 380°C, and even more preferably 25 to 350°C.

[0117] In the method for producing molded charcoal according to the present invention, by setting the molding temperature to be above the above lower limit, the mixture obtained in the mixing step is more suitably heated, and the binder in the mixture is adjusted to a desired viscosity, thereby spreading the binder over the entire surface of the bio-derived renewable resource char to further enhance the binding effect. At the same time, the binder can be more sufficiently penetrated into cavities and pores with a diameter of several μm that exist inside and between the bio-derived renewable resource char, thereby reducing or eliminating the cavities and pores to control the pore distribution, and the bio-derived renewable resource char is densified to improve the strength of the molded charcoal.

[0118] In the method for producing molded charcoal according to the present invention, by keeping the molding temperature below the above upper limit, it is possible to prevent the outflow of binder components from the molded body and prevent quality deterioration, further suppress cost increases due to energy loss, and further suppress molding defects caused by the adhesion of binder to the molds and rubber molds of the pressure molding apparatus.

[0119] In the method for producing molded charcoal according to the present invention, the time for molding the mixture in the molding process (molding time) is preferably 0.5 seconds to 60 minutes, more preferably 1 second to 45 minutes, even more preferably 3 seconds to 30 minutes, even more preferably 3 seconds to 10 minutes, and particularly preferably 3 seconds to 1 minute. In this application, molding time means the time for which a predetermined molding pressure is maintained.

[0120] In the method for producing molded charcoal according to the present invention, by having the molding time within the above range, the binder can permeate into the voids inherent in the mixture obtained in the mixing step and into the cavities of the carbonized bio-derived renewable resources, making it easier to reduce the pore size and to more easily achieve sufficient productivity.

[0121] In the method for producing molded charcoal according to the present invention, the molded product may be dried after molding in the molding process. By drying the molded product and hardening its surface, deformation, chipping, crumbling, cracking, etc., during transportation or intermediate inspection can be suppressed. The temperature during the above drying process (drying temperature) is preferably 100°C or more and 200°C or less, and the time during the above drying process (drying time) is more preferably 30 minutes or more and 24 hours or less.

[0122] In the method for producing molded charcoal according to the present invention, the bulk density of the molded product obtained in the molding process is 0.9 g / cm³. ３ 1.8g / cm or more ３ Preferably, it is 1.0 g / cm³. ３ 1.7g / cm or more ３ It is more preferable that the following is the case: 1.1 g / cm³ ３ 1.6g / cm or more ３ The following is even more preferable:

[0123] <Heat Treatment Process> In the method for producing molded charcoal according to the present invention, the molded product obtained in the molding process is heat-treated in the heat treatment process.

[0124] In the method for producing molded charcoal according to the present invention, when the molded product obtained in the molding process is heat-treated, one or more heat treatment devices can be selected from electric furnaces, externally heated rotary kilns, internal combustion rotary kilns, fluidized bed heating furnaces, screw heating furnaces, shaft furnaces, reed hammer furnaces, carbonization furnaces, etc.

[0125] In the method for producing molded charcoal according to the present invention, when the molded product obtained in the molding process is heat-treated, the heat treatment is carried out in an atmosphere in which the supply of oxygen is blocked or suppressed. The heat treatment is preferably carried out, for example, in a space in which the inflow of air is obstructed or in a space in which an inert gas is introduced, or in a state in which a filler such as packing coke that serves as an antioxidant is placed around the molded product obtained in the molding process.

[0126] In the method for producing molded charcoal according to the present invention, the temperature at which the molded product obtained in the molding process is heat-treated (heat treatment temperature) is preferably 400 to 1700°C, more preferably 500 to 1300°C, and even more preferably 600 to 1000°C.

[0127] In the method for producing molded charcoal according to the present invention, by setting the heat treatment temperature to be above the lower limit, the carbonized material of bio-derived renewable resources can be further sufficiently carbonized, and the carbonized particles of bio-derived renewable resources can be sufficiently bound together, thereby further improving the strength of the resulting molded charcoal. In the method for producing molded charcoal according to the present invention, by setting the heat treatment temperature to be below the upper limit, the decrease in the reactivity of the resulting molded charcoal with oxygen can be suppressed, and the decrease in the amount of heat generated due to the decrease in volatile matter can be suppressed, making it easier to reduce heat treatment costs.

[0128] In the method for producing molded charcoal according to the present invention, the heating rate used to raise the temperature of the molded product obtained in the molding process to the heat treatment temperature is preferably 1°C / hour to 1000°C / hour. In the method for producing molded charcoal according to the present invention, by having the heating rate used to raise the temperature of the molded product obtained in the molding process to the heat treatment temperature within the above range, it is possible to suppress the occurrence of cracks due to the rapid generation of volatile components caused by rapid heating, thereby making it easier to improve productivity while further reducing heat treatment costs.

[0129] In the method for producing molded charcoal according to the present invention, the cooling rate when the molded product obtained in the molding process is cooled to room temperature after heat treatment is preferably 1°C / hour to 1000°C / hour. In the method for producing molded charcoal according to the present invention, by having the cooling rate when the molded product obtained in the molding process is cooled to room temperature after heat treatment within the above range, the occurrence of cracks due to rapid cooling can be suppressed, and productivity can be improved more easily.

[0130] In the method for producing molded charcoal according to the present invention, the time for heat-treating the molded product obtained in the molding process (heat treatment time) is preferably 1 minute to 120 hours, more preferably 30 minutes to 48 hours, and even more preferably 1 hour to 36 hours.

[0131] In the method for producing molded charcoal according to the present invention, if the heat treatment time is equal to or greater than the above lower limit, variations in the degree of carbonization within the resulting molded charcoal can be further suppressed. In the method for producing molded charcoal according to the present invention, if the heat treatment time is equal to or less than the above upper limit, the productivity of molded charcoal can be more easily improved while further suppressing heat treatment costs. In this application, heat treatment time means the time from the moment the heat treatment temperature is reached until that temperature is maintained.

[0132] In the method for producing molded charcoal according to the present invention, when heat-treating the molded product obtained in the molding process, the following formula (I) { (D １ -D ２ ) / D １} × 100 (I) (However, D １ This is the bulk density (g / cm³) of the molded product obtained in the molding process. ３ ) and D ２ This is the bulk density (g / cm³) of the heat-treated product obtained in the heat treatment process. ３It is preferable to heat-treat the material so that the reduction rate of bulk density calculated by formula (I) is 3.0% or more and 30.0% or less, more preferably 4.0% or more and 28.0% or less, even more preferably 4.5% or more and 25.0% or less, even more preferably 5.0% or more and 25.0% or less, particularly preferably 5.0% or more and 20.0% or less, and even more preferably 5.0% or more and 18.0% or less. More specifically, in the method for producing molded charcoal according to the present invention, when heat-treating the molded product obtained in the molding process, it is preferable to heat-treat the material so that the reduction rate of bulk density calculated by formula (I) is 3.0% or more, more preferably 4.0% or more, even more preferably 4.5% or more, and even more preferably 5.0% or more. Furthermore, in the method for producing molded charcoal according to the present invention, when heat-treating the molded product obtained in the molding process, it is preferable to heat-treat it so that the reduction rate of bulk density calculated by the above formula (I) is 30.0% or less, more preferably 28.0% or less, even more preferably 25.0% or less, even more preferably 20.0% or less, and particularly preferably 18.0% or less.

[0133] In the method for producing molded charcoal according to the present invention, when heat-treating the molded product obtained in the molding process, the reduction rate of bulk density represented by formula (I) above is controlled to be within the above range, thereby easily achieving a reactivity with oxygen equivalent to that of coke.

[0134] In the method for producing molded charcoal according to the present invention, the amount of water or volatile matter contained in the resulting mixture, and the amount of gas such as air adsorbed onto the carbonized material of bio-derived renewable resources, can be controlled by appropriately controlling the mixing time and mixing temperature in the mixing step described above. On the other hand, if there is a large amount of water or volatile matter contained in the mixture, or gas such as air adsorbed onto the carbonized material of bio-derived renewable resources, the heat treatment material may explode due to their expansion during the heat treatment step, reducing the yield, or excessive pores with a pore size range of 0.001 μm to 0.200 μm may be generated, resulting in the resulting molded charcoal becoming excessively reactive with oxygen compared to coke and easily consumed. However, if too much water or volatile matter contained in the mixture, or gas such as air adsorbed onto the carbonized material of bio-derived renewable resources is removed, it becomes difficult to form pores with a pore size range of 0.001 μm to 0.200 μm, making it difficult to obtain the desired reactivity with oxygen in the resulting molded charcoal. Furthermore, the viscosity of the mixture increases, which can cause the mixer to stop due to overload during the mixing process. Additionally, the mixture may not flow sufficiently within the mold during the molding process, resulting in molding defects. Alternatively, the need to set a higher molding pressure can easily cause malfunctions in the molding equipment and molds. Under these circumstances, the inventors conducted extensive research and discovered that by controlling the rate of decrease in bulk density calculated from the bulk density of the molded product obtained in the molding process and the bulk density of the heat-treated product obtained in the heat-treatment process to within a predetermined range, it is possible to control the amount of water or volatile components contained in the mixture, as well as gases such as air adsorbed on the carbonized material of bio-derived renewable resources, to a desired range, thereby producing molded charcoal that exhibits the same reactivity with oxygen as coke. This led to the completion of the present invention.

[0135] In the method for producing molded charcoal according to the present invention, in the embodiment that includes a binder, it is particularly important to control the rate of decrease in bulk density within the above range. When molded charcoal contains a binder, the state of each component in the mixture tends to become uneven during the mixing process of carbonized material from bio-derived renewable resources and the binder, and variations in the bulk density of the molded product before the heat treatment process tend to occur. This variation in the bulk density of the molded product (initial state) before the heat treatment process affects the rate of volatile matter release and the state of shrinkage, so the rate of decrease in bulk density tends to fluctuate more easily compared to the case without a binder, and manufacturing variations tend to be larger. Therefore, by controlling the rate of decrease in bulk density during the heat treatment process within the above range, manufacturing variations when molded charcoal contains a binder can be controlled. As a result, the pore distribution of the obtained molded charcoal can be adjusted to a more appropriate range, and high strength that ensures air permeability and liquid permeability while having reactivity with oxygen can be maintained more stably.

[0136] In the method for producing molded charcoal according to the present invention, the bulk density of the heat-treated product obtained in the heat treatment step is 0.7 g / cm³. ３ 1.6g / cm or more ３ Preferably, the following: 0.8 to 1.5 g / cm³ ３ It is more preferable that the concentration be 0.9 to 1.4 g / cm³. ３ It is even more preferable that this be the case.

[0137] In the method for producing molded charcoal according to the present invention, the heat-treated product obtained in the heat treatment step may be used as the target molded charcoal as is, or the heat-treated product obtained in the heat treatment step may be further processed by cutting, machining, or other processes to obtain the desired dimensions and shape.

[0138] In the method for producing molded charcoal according to the present invention, the details of the molded charcoal obtained are as described in the description of the molded charcoal according to the present invention.

[0139] According to the present invention, it is possible to provide a method for easily producing molded charcoal containing bio-derived renewable resource char, which has high strength that ensures permeability and liquid permeability even when used as a substitute for coke in a cupola, and has a reactivity with oxygen equivalent to that of coke.

[0140] Next, the present invention will be described in more detail with reference to examples, but these are merely illustrative and not intended to limit the present invention.

[0141] (Examples 1-4, Comparative Example 1 and Comparative Example 2) Molded charcoal was prepared for Examples 1-4, Comparative Example 1 and Comparative Example 2 under the following conditions. In Examples 1-4, Comparative Example 1 and Comparative Example 2, molded charcoal was prepared under the same conditions for all steps except for "(2) Carbonization process" in "1. Preparation of bio-derived renewable resource carbonized material" and "(1) Mixing process" and "(2) Molding process" in "2. Preparation of molded charcoal".

[0142] 1. Preparation of bio-derived renewable resource charred material The bio-derived renewable resource charred material was prepared by the following method: (1) Crushing process Wood (Japanese cedar) that had been dried in advance to a moisture content of 15% by mass was selected as biomass, and this wood was crushed to a size of 20 to 50 mm using a chipper. (2) Carbonization process The crushed biomass obtained in the crushing process in (1) above was placed in a graphite crucible, and the lid was closed. Packing coke, which is an antioxidant, was placed around the crucible, and it was placed in an electric furnace. Next, nitrogen gas was flowed into the electric furnace (flow rate: 3 to 5 liters / minute), and the crushed biomass was carbonized by heating in a non-oxidizing atmosphere to obtain biomass charred material. In Example 1, the carbonization temperature was 600°C. In Example 2, the carbonization temperature was 400°C. In Example 3, the carbonization temperature was 380°C. In Example 4, the carbonization temperature was 320°C. In Comparative Example 1, the carbonization temperature was 300°C. In Comparative Example 2, the carbonization temperature was 650°C. In all cases, the heating rate from room temperature to the carbonization temperature was 5°C / minute, the carbonization time was 60 minutes, and the cooling rate from the carbonization temperature to room temperature was 10°C / minute. The oxygen concentration inside the electric furnace from the start to the end of heating was less than 1% in all cases. (3) Grinding Process The biomass carbonized material obtained in the carbonization process described in (2) above was ground down in stages using a plastic pulverizer (model: JC-5) manufactured by Morita Seiki Kogyo Co., Ltd., a hammer mill (model: HM-100) manufactured by Daiki Sangyo Co., Ltd., and an ACM pulverizer (model: ACM-H) manufactured by Hosokawa Micron Corporation, in sequence, to produce bio-derived renewable resource carbonized material with a maximum particle size of 50 μm and a median particle size of 15 μm. Furthermore, the maximum particle size and median particle size of the above-mentioned bio-derived renewable resource char are, respectively, the cumulative particle size in the volume-integrated particle size distribution obtained using a laser diffraction / scattering particle size distribution analyzer (model: Partica LA-960) manufactured by Horiba, Ltd., where 100% of the particle size (volume-integrated particle size at 100% of the cumulative volume, D １００ ) and 50% particle size (volume cumulative particle size at 50% cumulative volume, D ５０ ) means.

[0143] 2. Preparation of molded charcoal (1) Mixing process A mixture was prepared by mixing 100 parts by mass of each bio-derived renewable resource charcoal obtained in "1. Preparation of bio-derived renewable resource charcoal" with 60 parts by mass of fructose (residual charcoal content: 40% by mass) as a binder, while heating using a mixer manufactured by Inoue Seisakusho Co., Ltd. (model: Trimix® TX-0.5). In Example 1, mixing was carried out at a mixing temperature of 70°C for 30 minutes. In Example 2, mixing was carried out at a mixing temperature of 120°C for 60 minutes. In Example 3, mixing was carried out at a mixing temperature of 100°C for 50 minutes. In Example 4, mixing was carried out at a mixing temperature of 50°C for 20 minutes. In Comparative Example 1, mixing was carried out at a mixing temperature of 20°C for 5 minutes. In Comparative Example 2, mixing was carried out at a mixing temperature of 150°C for 130 minutes. In all examples, the volume ratio in the mixing process was 85% by volume. (2) Molding Process The mixture obtained in the mixing process described above was filled into the molding space of a mold having one hollow female mold (outer diameter: 100 mm, inner diameter: 50 mm, length: 100 mm) and two solid male molds (outer diameter: 50 mm, length: 25 mm) (for being pressed into the hollow part of the female mold). A predetermined pressure was applied to the mixture by pressing one of the male molds with a 150-ton press machine to produce a cylindrical molded product (shape: outer diameter approximately 50 mm, height approximately 25 mm). In Example 1, molding was performed by applying pressure at a molding pressure of 40 MPa for 30 seconds. In Example 2, molding was performed by applying pressure at a molding pressure of 30 MPa for 5 seconds. In Example 3, molding was performed by applying pressure at a molding pressure of 35 MPa for 15 seconds. In Example 4, molding was performed by applying pressure at a molding pressure of 50 MPa for 10 seconds. In Comparative Example 1, molding was performed by applying pressure at a molding pressure of 10 MPa for 4200 seconds. In Comparative Example 2, the molding was performed by applying pressure at a molding pressure of 160 MPa for 0.3 seconds. In both cases, the molding temperature was 25°C. (3) Heat treatment process The molded product obtained in (2) the molding process was placed in an electric furnace while packing coke, which is an antioxidant, was placed around the molded product.Next, nitrogen gas was flowed into the electric furnace (flow rate: 3-5 liters / minute) to create a non-oxidizing atmosphere with an oxygen concentration of less than 1%. The temperature was then raised from room temperature to 1000°C at a heating rate of 25°C / hour, heated at the same temperature for 2 hours, and then cooled down to room temperature at a cooling rate of 30°C / hour. In Example 1, under the above conditions, the molded charcoal (V.) was heat-treated so that the reduction in bulk density was 16.0%. ｂ :0.41mL / g, S ａ : 12.2m ２ A mass of 1 / g was obtained. In Example 2, the above conditions were used to heat-treat the material so that the reduction in bulk density was 4.8%, thereby obtaining molded carbon (V ｂ :0.38mL / g, S ａ : 4.49m ２ A mass of 1 / g was obtained. In Example 3, the above conditions were used to heat-treat the material so that the reduction in bulk density was 15.3%, thereby obtaining molded carbon (V ｂ :0.50mL / g, S ａ : 6.70m ２ A mass of 1 / g was obtained. In Example 4, under the above conditions, the mass of molten carbon (V) was heat-treated so that the reduction rate of bulk density was 12.7%. ｂ :0.56mL / g, S ａ : 8.96m ２ A charred carbon (V) was obtained by heat treatment under the above conditions so that the reduction rate of bulk density was 35.5%. In Comparative Example 1, charred carbon (V) was obtained by heat treatment under the above conditions so that the reduction rate of bulk density was 35.5%. ｂ :0.89mL / g, S ａ : 16.6m ２ In Comparative Example 2, the above conditions were used to heat-treat the material so that the reduction in bulk density was 1.5%, thereby obtaining molded carbon (V ｂ :0.38mL / g, S ａ : 5.29m ２ The result was obtained ( / g). The cumulative volume within all pores in the pore diameter range of 0.001 μm to 1000 μm was V ｂ The cumulative specific surface area within all pores in the pore diameter range of 0.001 μm to 1000 μm is S. ａ Let's assume that.

[0144] Table 1 shows the manufacturing conditions for the above manufacturing method (in Table 1, only the differences between the examples and comparative examples are shown for the molten charcoal production conditions). Note that the molten product obtained in "(2) Molding Process" of "2. Production of Molded Charcoal" above is soft, and there is a risk that its shape will be deformed when measuring the dimensions of the molten product, making it impossible to accurately measure the bulk density. Therefore, the molten product was dried at 110°C for 12 hours using a dryer manufactured by Advantec Toyo Co., Ltd. (model: FC-410) to harden the surface of the molten product, and then the dimensions of the obtained molten product were measured. Furthermore, for each molded coal obtained, the ratio of the cumulative pore volume in pores with a diameter range of 2 μm to 1000 μm to the total pore volume, the ratio of the cumulative specific surface area in pores with a diameter range of 0.001 μm to 0.200 μm to the cumulative specific surface area in all pores, cold compressive strength, porosity, oxidation loss rate, absolute value of the difference in oxidation loss rates, evaluation of oxidation loss rate, total calorific value, and ash content were determined. The results are listed in Table 2, and various measurement results are shown in Figures 3, 4, 5, and 6. Figure 3 shows the relationship between pore diameter and pore volume in the molded coal obtained in the examples and comparative examples. Figure 4 shows the relationship between pore diameter and the ratio of cumulative pore volume to total pore volume (cumulative pore volume ratio) in the molded coal obtained in the examples and comparative examples. Figure 5 shows the relationship between pore diameter and specific surface area in pores in the molded coal obtained in the examples and comparative examples. Figure 6 shows the relationship between pore diameter and the ratio of the total specific surface area to the total specific surface area within all pores (total specific surface area ratio within pores) in the molded coal obtained in the examples and comparative examples. For comparison, Table 2, Figures 3, 4, 5, and 6 also include the results of measurements of each physical property of commercially available coke for foundrying.

[0145] The evaluation methods for each physical property in the examples and comparative examples are described below.

[0146] <Total pore volume> The total pore volume was measured in accordance with JIS R 1655:2003 as follows. A test piece cut from the formed carbon into a size of about 5 mm × 5 mm × 10 mm was used. After degreasing with acetone, it was processed in a vacuum dryer (model: VO-320) manufactured by Advantec Toyo Co., Ltd. at an absolute pressure of 11.3 kPa, a drying temperature of 130°C, and a drying time of 10 hours. Next, the mass of the test piece was measured with an electronic balance. Then, using an automatic mercury porosimeter pore size distribution measuring device (model: AutoPore V) manufactured by Micromeritics Instrument Corp., the integrated volume within all pores in the pore size range of 0.001 μm or more and 1000 μm or less, which is the measurement range, was measured.

[0147] <Ratio of integrated pore volume> The total pore volume V ｂ and the integrated volume V within the pores with a pore size of 2 μm or more and 1000 μm or less ｃ When obtained, it was calculated by (V ｃ / V ｂ ) × 100.

[0148] <Specific surface area within all pores> The specific surface area within all pores was measured in accordance with JIS R 1655:2003 as follows. A test piece cut from the formed carbon into a size of about 5 mm × 5 mm × 10 mm was used. After degreasing with acetone, it was processed in a vacuum dryer (model: VO-320) manufactured by Advantec Toyo Co., Ltd. at an absolute pressure of 11.3 kPa, a drying temperature of 130°C, and a drying time of 10 hours. Next, the mass of the test piece was measured with an electronic balance. Then, using an automatic mercury porosimeter pore size distribution measuring device (model: AutoPore V) manufactured by Micromeritics Instrument Corp., the integrated specific surface area within all pores in the pore size range of 0.001 μm or more and 1000 μm or less, which is the measurement range, was measured.

[0149] <Ratio of integrated specific surface area> The integrated specific surface area S within all pores ａ and the integrated specific surface area S within the pores in the pore size range of 0.001 μm or more and 0.200 μm or less ｂ When obtained, it was calculated by (S ｂ / S ａ ) × 100.

[0150] <Cold Compressive Strength> Using a test piece cut from the formed carbon to a size of 10 mm × 10 mm × 20 mm with JIS intermediate machining accuracy, and using a universal testing machine (model: AG-Xplus 100 kN) manufactured by Shimadzu Corporation, at room temperature, a stress-strain diagram was obtained by continuously applying a load at a compression speed of 0.2 mm / second until the test piece was destroyed, and the maximum stress value obtained from the stress-strain diagram obtained at this time was determined as the cold compressive strength value.

[0151] <Porosity> The porosity was measured in accordance with JIS R 1655:2003 as follows. Using a test piece cut from the formed carbon to a size of about 5 mm × 5 mm × 10 mm, after degreasing with acetone, it was treated with a vacuum dryer (model: VO-320) manufactured by Advantec Toyo Co., Ltd. at an absolute pressure of 11.3 kPa, a drying temperature of 130 °C, and a drying time of 10 hours. Next, the mass of the test piece was measured with an electronic balance. Then, using an automatic mercury porosimeter pore size distribution measuring device (model: AutoPore V) manufactured by Micromeritics, the total pore volume V within the pores of the pores within the measurement range of pore diameters from 0.001 μm or more to 1000 μm or less ｂ (mL / g), the volume V of the test piece ａ (cm ３ ) was measured, and the porosity (volume %) = {total pore volume V ｂ (mL / g) × mass of the test piece (g) / volume V of the test piece ａ (cm ３ )} × 100 was calculated.

[0152] <Apparent Density> The mass (g) of a formed product or heat-treated product with an outer diameter of about 50 mm and a length of about 25 mm was measured with an electronic balance (model: LE244S) manufactured by Sartorius AG, and the dimensions of the formed product or heat-treated product after drying were measured with a micrometer to obtain the volume (cm ３ ), and it was calculated from the mass and volume of the obtained measurement sample, respectively. <00​​​​​​​​​It was calculated using the following formula: {(D １ -D ２ ) / D １} × 100

[0154] <Moisture Content> The moisture content was measured in accordance with JIS M 8812:2006 as follows. The sample was placed on a dried porcelain dish of known mass and dried at 200°C for 4 hours. After that, the porcelain dish was cooled on a cold metal plate for 1 minute, and then cooled further in a desiccator for 10 minutes. The mass of the porcelain dish was measured using a Sartorius AG electronic balance (model: LE244S) to determine the mass loss of the sample before and after drying, and the moisture content was calculated.

[0155] <Volatile Content> The volatile content was calculated by placing carbonized bio-derived renewable resources on a dried porcelain plate and placing it in an electric furnace, drying it at 200°C for 4 hours to remove moisture, and then measuring the mass loss from room temperature to 1000°C using a Rigaku Corporation differential thermal balance TG-DTA (model: TG8120) under the conditions of a heating rate of 10°C / min and a nitrogen gas flow rate of 1 L / min.

[0156] <Particle Size of Bio-derived Renewable Resources> The particle size of bio-derived renewable resources was measured in accordance with JIS Z 8825:2013 as follows. Bio-derived renewable resources were dispersed by ultrasound in an aqueous solution of 10 parts by mass of amphoteric surfactant added to 100 parts by mass of distilled water. The dispersed particles of bio-derived renewable resources were flowed into a measurement cell in a laser diffraction / scattering particle size distribution analyzer (model: Partica LA-960) manufactured by Horiba, Ltd., and a semiconductor laser (650 nm) was irradiated as a light source. The scattered light was detected and analyzed by a ring-shaped detector, and the cumulative particle size in the volume cumulative particle size distribution was determined as the particle size at 100% (volume cumulative particle size at 100% cumulative volume, D １００ ) and 50% particle size (volume cumulative particle size at 50% cumulative volume, D ５０ ) was measured.

[0157] <Carbon Residue Rate> The binder was placed on a dried porcelain plate and placed in an electric furnace. After drying at 200°C for 4 hours to remove moisture, the carbon residue rate was determined from the change in mass of the binder when it was heated from room temperature to 1000°C using a Rigaku differential thermometer TG-DTA (model: TG8120) under the conditions of a heating rate of 10°C / min and a nitrogen gas flow rate of 1 L / min. The total mass of the binder before heat treatment was W. Ａ (g) The mass of the binder after heat treatment is W Ｃ When (g) is used, the residual carbon percentage (mass%) = (W Ｃ / W Ａ It was calculated by multiplying by ) × 100.

[0158] <Total Calorific Value> The total calorific value was measured in accordance with JIS M 8814:2003 as follows. The sample was reduced in size while being pulverized, and the material that passed through a 212 μm sieve was spread into a thin layer at room temperature and allowed to roughly equilibrate with the atmosphere of the measurement room. Then, it was measured using an IKA cylinder-type calorimeter (model: C 6000 global standards).

[0159] <Ash Content> The ash content was measured in accordance with JIS M 8812:2006 as follows. The sample was placed on a dried porcelain dish of known mass, and dried at 200°C for 4 hours using an Advantec Toyo Co., Ltd. dryer (model: FC-410) to remove moisture. The mass of the porcelain dish was then measured using a Sartorius AG electronic balance (model: LE244S). Subsequently, the dried sample, still on the porcelain dish, was placed in a Denken Highdental Co., Ltd. electric furnace (model: KDF-500Plus), air (flow rate: 5 liters / min) was introduced into the electric furnace to create an oxidizing atmosphere, and the furnace was heated at 815°C for 2 hours. The mass of the porcelain dish was then measured using a Sartorius AG electronic balance (model: LE244S). The ash content was calculated from the mass of the sample before and after heating in the electric furnace using the following formula. Ash content (mass %) = (mass of the sample after heating in the electric furnace / mass of the sample before heating in the electric furnace) × 100

[0160] <Oxidation Loss Rate> The mass of a test specimen cut to a size of 15 mm x 15 mm x 15 mm was measured using a Sartorius AG electronic balance (model: LE244S). Next, the test specimen was placed on a dried porcelain dish of known mass and placed in an electric furnace (model: KDF-500Plus) manufactured by Denken Heidental Co., Ltd. Heat treatment was performed in an atmospheric environment by raising the temperature inside the furnace from room temperature to 950°C over 2 hours, and then holding it at 950°C for 4 hours. After the heat treatment, the test specimen, along with the porcelain dish, was removed from the electric furnace and cooled on a cold metal plate for 10 minutes, then cooled further in a desiccator for 20 minutes. The mass of the porcelain dish, along with the test specimen, was measured using a Sartorius AG electronic balance (model: LE244S) to determine the mass loss rate of the measured sample, and the obtained mass loss rate was defined as the oxidation loss rate (mass%).

[0161] <Absolute Value of Difference in Oxidation Loss Rate> The difference between the oxidation loss rate (mass%) of each molded coal obtained by the method described above and the oxidation loss rate (mass%) of commercially available foundry coke was calculated, and the absolute value of the obtained difference was taken as the absolute value of the difference in oxidation loss rate. Based on the obtained absolute value of the difference in oxidation loss rate, the following criteria were used for evaluation: A: The absolute value of the difference in oxidation loss rate is 5.0 or less. B: The absolute value of the difference in oxidation loss rate is greater than 5.0 and 8.0 or less. C: The absolute value of the difference in oxidation loss rate is greater than 8.0. The smaller the absolute value of the difference in oxidation loss rate, the more likely it is to exhibit reactivity with oxygen similar to commercially available foundry coke. Therefore, in the above evaluation criteria, A > B > C means that the reactivity with oxygen is similar to that of commercially available foundry coke and is preferable as a substitute for commercially available foundry coke. Furthermore, if the oxidation loss rate of shaped charcoal is too high compared to that of commercially available coke for casting, resulting in a large absolute difference in the oxidation loss rates, the amount of shaped charcoal to be fed into the cupola will increase, leading to higher costs. Conversely, if the oxidation loss rate of shaped charcoal is too low compared to that of commercially available coke for casting, resulting in a large absolute difference in the oxidation loss rates, it means that the shaped charcoal does not react easily with oxygen. This can easily lead to a decrease in the quality of the castings due to a drop in furnace temperature, and increased complexity of manufacturing conditions due to changes in the input ratio of ingot, coke for casting, and slag-forming agent.

[0162]

[0163]

[0164] Table 2 shows that the molded charcoal containing bio-derived renewable resource char obtained in Examples 1 to 4 has a cumulative pore volume ratio of pores with a diameter range of 2 μm to 1000 μm to the total pore volume of 60 volume% or less, and a cumulative specific surface area ratio within pores with a diameter range of 0.001 μm to 0.200 μm to the total pore volume of pores of 60% to 90%. It has high cold compressive strength and an oxidation loss rate similar to that of coke for foundrying, and therefore, even when used as a substitute for coke in a cupola, it has high strength that ensures permeability and liquid permeability, and it has a reactivity with oxygen of a similar degree to that of coke.

[0165] Furthermore, as can be seen from Table 2, the molded charcoal containing bio-derived renewable resource char obtained in Comparative Example 1 has a low cold compressive strength because the ratio of the cumulative pore volume in pores with a diameter range of 2 μm to 1000 μm to the total pore volume exceeds 60 volume%, and the ratio of the cumulative specific surface area in pores with a diameter range of 0.001 μm to 0.200 μm to the total specific surface area exceeds 90%, resulting in an oxidation loss rate evaluation of "C". Therefore, when used as a substitute for coke in a cupola, it is clear that the desired strength and reactivity with oxygen equivalent to that of coke cannot be obtained. Similarly, as shown in Table 2, the molded charcoal obtained in Comparative Example 2, which contains biomass charcoal derived from renewable resources, has a high cold compressive strength because the ratio of the cumulative pore volume in pores with a diameter range of 2 μm to 1000 μm to the total pore volume is 60 volume% or less. However, the ratio of the cumulative specific surface area in pores with a diameter range of 0.001 μm to 0.200 μm to the total specific surface area in pores is less than 60%, resulting in an oxidation loss rate evaluation of "C". Therefore, when used as a substitute for coke in a cupola, the desired strength can be obtained, but the reactivity with oxygen equivalent to that of coke cannot be obtained.

[0166] Figure 4 shows the relationship between pore size and the ratio of cumulative pore volume to total pore volume (cumulative pore volume ratio) in foundry coke and shaped charcoal containing bio-derived renewable resource carbides according to the present invention (examples and comparative examples). From Figure 4, the difference between foundry coke and shaped charcoal containing bio-derived renewable resource carbides can be seen. The curve for foundry coke rises sharply at a pore size of 100 to 200 μm, then rises in a gradual curve, while the curve for shaped charcoal according to the present invention rises in stages, rising at a pore size of 100 to 300 μm, then rising gradually to a pore size of 3 to 100 μm, then rising sharply at a pore size of 2 to 3 μm, and then rising again gently at a pore size of around 0.3 μm. This difference is thought to stem from the fact that coke for foundrying consists solely of raw coal and is produced by carbonization, while the molded charcoal in the examples and comparative examples is composed of bio-derived renewable resource charcoal and heat-treated binder material, and is produced through multiple processes such as mixing, molding, and heat treatment. The bio-derived renewable resource charcoal that mainly constitutes molded charcoal has pores with a diameter of several μm to about 10 μm, which originate from the water and volatile components removed during the biomass carbonization process. Furthermore, the heat treatment process removes water, volatile components contained in the binder, and air incorporated during mixing, and it is thought that fine pores with a diameter of around 1 μm and less than 1 μm, which are thought to originate from these, are also formed in the molded charcoal containing bio-derived renewable resource charcoal.

[0167] According to the present invention, it is possible to provide molded charcoal containing bio-derived renewable resource charcoal that has high strength to ensure permeability and liquid permeability even when used as a substitute for coke in a cupola, and has a reactivity with oxygen equivalent to that of coke, and to provide a method for producing molded charcoal containing bio-derived renewable resource charcoal.

[0168] This application claims priority based on Japanese Patent Application No. 2025-024794, filed on 19 February 2025, and incorporates all of its disclosures herein.

[0169] BC Bed coke layer I Ingot layer L Slag-forming layer C Coke layer T Tuyer F Melting furnace S Slag E Tappot FE Molten iron

Claims

1. Molded charcoal containing bio-derived renewable resource char, characterized in that the ratio of the cumulative pore volume in pores with a pore diameter range of 2 μm to 1000 μm to the total pore volume is 60% by volume or less, and the ratio of the cumulative specific surface area in pores with a pore diameter range of 0.001 μm to 0.200 μm to the cumulative specific surface area in all pores is 60% to 90%.

2. The molded charcoal according to claim 1, characterized in that its cold compressive strength is 20 MPa or more.

3. Molded charcoal according to claim 1 or 2, characterized in that the porosity is 15 to 60 volume percent.

4. A method for producing molded charcoal according to claim 1, comprising: a mixing step of mixing carbonized material of a bio-derived renewable resource with a binder; a molding step of molding the mixture obtained in the mixing step; and a heat treatment step of heat treating the molded product obtained in the molding step, wherein in the heat treatment step, the following formula (I) {(D １ -D ２ ) / D １ } × 100 (I) (However, D １ This is the bulk density (g / cm³) of the molded product obtained in the molding process. ３ ) and D ２ This is the bulk density (g / cm³) of the heat-treated product obtained in the heat treatment process. ３ A method for producing molded charcoal, characterized by heat treatment such that the rate of decrease in bulk density calculated by ) is 3.0% or more and 30.0% or less.

5. The method for producing molded charcoal according to claim 4, wherein the molding pressure in the molding step is 20 to 200 MPa and the molding time is 0.5 seconds to 60 minutes.

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