Manufacturing method of briquettes

Abstract

To provide briquettes of charcoal having improved combustion performance and allowing easy ignition, and a method for producing the briquettes. Briquette charcoal is made from aggregates containing graphite powder and wood flour, and a binder containing carboxymethyl cellulose or starch.

Description

[Technical field]

[0001] The present invention relates to briquettes containing graphite powder and a method for producing the same. [Background technology]

[0002] Charcoal produces little smoke, flames, or odors when burned, and the radiant heat, including infrared rays (near infrared and far infrared), can brown the surface of food and lock in the umami components. In addition, since no moisture is produced when charcoal is burned, food is cooked to a crisp on the surface. As charcoal has these favorable characteristics for cooking, it is widely used as a solid fuel for cooking.

[0003] For example, charcoal with excellent combustion performance such as Binchotan charcoal is expensive because it is produced at high temperatures by dry distilling (carbonizing) wood to remove as many components as possible other than carbon. Therefore, although alternative charcoal such as sawdust is available on the market, it does not have the same combustion performance as Binchotan charcoal.

[0004] Here, for example, charcoal for cooking is required to have a large calorific value and a relatively long burning time. In particular, charcoal used in ordinary households and camping is required to have high combustion performance, including easy ignition, in addition to the above.

[0005] For example, Patent Document 1 discloses the production of briquettes for fuel by mixing 5 to 25% of artificial graphite powder with raw material charcoal powder consisting of 80% or more carbonaceous carbide. The addition of artificial graphite powder is expected to improve the calorific value and burning time, and to improve the bulk density of the briquettes, so it is said that by controlling the density of the briquettes, it is possible to impart various properties to the briquettes, such as bringing the combustion performance closer to that of binchotan charcoal and making it easier to ignite. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2006-306925 A Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, in order to obtain the raw charcoal, it is necessary to dry distill organic matter such as coniferous trees, sawdust, and bark, which are the raw materials for charcoal, at around 400 to 700°C. It is also disclosed that wood vinegar tar and polyvinyl alcohol are used as binders (binding agents) in the molding. However, there is a problem in that potassium or calcium needs to be attached to the surface of the molded charcoal to make it easier to ignite. In addition, since the content of artificial graphite powder is a maximum of 25%, the improvement in combustion performance is limited.

[0008] The present invention has been made in view of the above problems, and has improved combustion performance that allows easy ignition. Manufacturing method of briquettes The purpose is to provide. [Means for solving the problem]

[0013] Claim 1 The method for producing briquettes of the invention includes a mixing step of forming a mixture of 100 parts by mass of aggregate containing graphite powder and wood powder, the graphite powder being 30 to 50 parts by mass, and a binder containing carboxymethyl cellulose or starch, the binder being 3 to 15 parts by mass relative to 100 parts by mass of the aggregate; a kneading step of forming a kneaded material by kneading the mixture at 110 to 200°C while adding water; and a molding step of molding the mixture into a predetermined shape.

[0014] According to the above-mentioned configuration, the graphite powder and the aggregate containing wood powder are bound together by the binder containing carboxymethyl cellulose or starch to form a robust briquettes. The briquettes contain wood powder, which has a lower ignition temperature than the graphite powder, and therefore can be easily ignited. Furthermore, since the proportion of graphite powder in the aggregate is high, the calorific value and burning time can be improved, thereby improving the burning performance.

[0015] Claim 2 The method for producing briquettes of the invention is as follows: 1 The present invention is characterized by having a heat treatment step of heat treating the molded product at 700 to 1000° C. in a non-oxidizing atmosphere. According to the above-mentioned configuration, the amount of fixed carbon in the briquettes of charcoal is increased by the heat treatment, so that the calorific value is increased and the combustion performance is improved. Effect of the Invention

[0016] The present invention According to the method for producing briquettes, The briquettes can be easily ignited, and the combustion performance of the briquettes can be improved. [Brief description of the drawings]

[0017] [Figure 1] 1 is a briquetted charcoal according to a first embodiment of the present invention. [Diagram 2] 1A-1D are diagrams illustrating the steps of forming briquettes of the present invention. [Diagram 3] 1A is a graph showing the TG curve of Example 1, and FIG. 1B is a graph showing the DTA curve of Example 1. [Figure 4] 1A is a graph showing the TG curve of Example 2, and FIG. 1B is a graph showing the DTA curve of Example 2. [Diagram 5] 1A is a graph showing the TG curve of Comparative Example 1, and FIG. 1B is a graph showing the DTA curve of Comparative Example 1. [Figure 6] 1A is a graph showing the TG curve of Comparative Example 2, and FIG. 1B is a graph showing the DTA curve of Comparative Example 2. [Figure 7] 1A is a graph showing the TG curve of Comparative Example 3, and FIG. 1B is a graph showing the DTA curve of Comparative Example 3. [Figure 8] 1 is a table showing the transition of combustion temperature in Examples 1 and 2 and Comparative Examples 1 to 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, the embodiment for carrying out the present invention will be described in detail, however, the present invention is not limited to the following embodiment.

[0019] The formed charcoal shown in FIG. 1 is formed by binding powdered aggregates including graphite powder and wood powder with a binder. As the graphite powder, powder of artificial graphite or powder of natural graphite such as flake graphite or soil graphite can be used. The powder of artificial graphite is shavings generated when cutting graphite products from an artificial graphite block, and is usually discarded. By using such shavings, waste or by-products can be effectively utilized at low cost.

[0020] The wood powder can be, for example, crushed wood that is discarded, or sawdust generated when cutting wood from logs or processing wood. Coniferous trees such as cedar, cypress, and hemlock are widely used as wood, and wood powder from these coniferous trees is easily available. Molded charcoal containing wood powder produces a scent unique to the trees that have been powdered during burning, so it is possible to tailor the scent to one's taste by selecting the type of tree. Note that wood powder from broad-leaved trees such as cherry trees may also be used, and the type of tree is not particularly limited.

[0021] Carboxymethylcellulose is preferred as the binder, but starch can also be used. A mixture of carboxymethylcellulose and starch can also be used as the binder. These are available in grades that can be used as food additives, do not produce harmful substances when burned, and can be used safely when heating food.

[0022] In the case of briquettes, 30 to 50 parts by mass of graphite powder is used out of 100 parts by mass of aggregate. Since the proportion of graphite powder that contains almost no components other than carbon is high, the combustion performance (calorific value, burning time, etc.) of the briquettes is improved. In addition, since the briquettes contain wood powder, ignition is easy.

[0023] Next, the process of forming the briquettes will be described with reference to FIG. 2. In the first mixing process, graphite powder and wood powder, which are aggregates, are mixed with a powdered binder in a predetermined ratio. For 100 parts by mass of aggregate, 30 to 50 parts by mass of graphite powder and the remainder is wood powder. The binder may be mixed in a ratio of 3 to 15 parts by mass with respect to 100 parts by mass of aggregate. Mixing may be performed manually using, for example, a stirring rod, or may be performed using, for example, a V-type mixer or a double cone type mixer. There is no particular limitation on the mixing means as long as the graphite powder, wood powder, and binder can be mixed sufficiently so as to be uniformly mixed.

[0024] In the kneading process, the mixture mixed in the mixing process is kneaded while adding water, and the aggregates are bound together by a binder. The kneading is performed using a commercially available mixer, and for example, a kneaded mixture is formed by adding water appropriately while applying friction to the mixture by rotating a screw. The temperature during this kneading is preferably 110 to 200°C, more preferably about 120 to 170°C, depending on the type of aggregate and binder.

[0025] In the molding step, the mixture formed in the kneading step is molded using a commercially available compression molding machine. The mixture is extruded from the nozzle of the compression molding machine and cut to an appropriate length by a rotary blade to become a molded product, and this molded product is the briquettes. The shape of the briquettes is not particularly limited, but it can be a cylindrical shape with a diameter of 20 to 40 mm and a length of 20 to 100 mm so that it is easy to mold and easy to handle.

[0026] The formed product (formed charcoal) may be heat-treated in a heat treatment step to carbonize the wood powder and binder. This heat treatment is preferably performed in a non-oxidizing atmosphere (reducing atmosphere or inert gas atmosphere such as nitrogen gas) at a heat treatment temperature of 700 to 1000°C. The heat treatment eliminates the aroma emitted from the wood powder during combustion, but reduces the moisture and other released during combustion, increases the amount of fixed carbon, and improves combustion performance.

[0027] Next, the briquettes of Examples 1 and 2 of the present invention will be described. The wood powder was 62 parts by mass (31 kg) of coniferous wood such as cedar, and the aggregate was 38 parts by mass (19 kg) of graphite powder obtained by cutting artificial graphite. 5 parts by mass (2.5 kg) of commercially available carboxymethyl cellulose was used as a binder for 100 parts by mass of the aggregate.

[0028] In the mixing process, the aggregate and binder were mixed uniformly in a metal container using a metal stirring rod. In the kneading process, a screw-type mixer was used to knead the aggregate and binder mixture at about 150°C while adding water appropriately. In the molding process, a commercially available compression molding machine was used to extrude the mixture from the kneading process through a cylindrical nozzle with an inner diameter of 30 mm to mold it into a cylindrical shape, and then cut it into lengths of about 30 to 100 mm with a rotary blade.

[0029] Example 1 is a briquetted charcoal in the form of a briquetted product, and has a bulk density of 0.83 g / cm 3 Example 2 is a shaped charcoal obtained by carbonizing the wood powder and binder contained in the shaped product in a heat treatment process, and the bulk density was 0.73 g / cm 3 In the heat treatment process, a commercially available vertical tubular furnace was used to perform heat treatment in a nitrogen atmosphere at 920°C for 10 minutes.

[0030] The briquettes of Examples 1 and 2 and the commercially available products (Comparative Examples 1 to 3) were subjected to industrial analysis (measurement of moisture, ash, volatile matter, and fixed carbon) in accordance with JIS M 8812, measurement of calorific value in accordance with JIS M 8814, and measurement using a differential thermobalance. A calorific value was measured using a Calorimeter C5000 2 / 12 (manufactured by IKA).

[0031] Thermogravimetric differential thermal analysis (TG-DTA: Thermo Gravity-Differential Thermal Analysis) was performed in an air atmosphere at a temperature range of 30 to 800°C at a heating rate of 10°C / min using a differential thermobalance TG-DTA7200 (manufactured by SII Nanotechnology Inc.). In the TG curve, mass loss due to vaporization of moisture and volatile matter before the sample combustion in the low temperature region and large mass loss due to combustion after the sample combustion starts are observed. In addition, an exothermic peak due to the combustion of the sample is observed in the DTA curve.

[0032] Table 1 shows the results of proximate analysis (moisture, ash, volatile matter, fixed carbon), calorific value, and ignition temperature for Examples 1 and 2 and Comparative Examples 1 to 3. The ignition temperature was determined as the intersection of the extension of the straight line portion of the mass change in the temperature region before combustion and the extension of the straight line portion of the initial mass change due to combustion in the TG curves for Examples 1 and 2 and Comparative Examples 1 to 3 in Figs. 3 to 7, and the temperature at that time was determined as the ignition temperature. Comparative Example 1 used Kishu Binchotan charcoal (bulk density 1.03 g / cm 3 ), and Comparative Example 2 is sawdust charcoal (bulk density 1.06 g / cm 3 ), and Comparative Example 3 is charcoal made from mangroves from the Malaysian Forestry Agency (bulk density 0.87 g / cm 3 ) and all of them are readily available commercially.

[0033] [Table 1]

[0034] The briquettes of Example 1 contained uncarbonized wood powder and a binder, and therefore had a large volatile content of 26.9% by mass and an ignition temperature of 260° C. This is believed to indicate the characteristics of having a lower ignition temperature and easier ignition than those of Example 2 and Comparative Examples 1 to 3. In addition, three exothermic peaks were observed in the DTA curve (see FIG. 3), and the two peaks on the low temperature side were believed to be due to the wood powder and the binder, and the exothermic peak on the highest temperature side was believed to be due to the graphite powder.

[0035] The briquettes of Example 2 had approximately the same ignition temperature and calorific value as the binchotan charcoal of Comparative Example 1. Moreover, compared to Comparative Example 1, Example 2 had a large volatile content of 7.5 mass%, which is considered to make it easier to ignite. Furthermore, two exothermic peaks were observed in the DTA curve (see FIG. 4), and the exothermic peak on the low temperature side is considered to be due to the carbonized wood powder and binder, and the exothermic peak on the high temperature side is considered to be due to the graphite powder. In addition, in Reference Examples 1 to 3, there was only one exothermic peak in each DTA curve (see FIG. 5, FIG. 6, and FIG. 7).

[0036] Next, a combustion experiment was carried out using each of Examples 1 and 2 and Comparative Examples 1 to 3 as fuel. Here, about 140 g of fuel was placed in a commercially available stove (Hida Stove 14 cm, manufactured by Wahei Freiz Co., Ltd.), and ignited and burned with a gas burner. Figure 8 shows the transition of the combustion temperature in Examples 1 and 2 and Comparative Examples 1 to 3. The combustion temperature was measured at five points on the surface of the fuel every 5 minutes from immediately after ignition (0 minutes) until 30 minutes had passed, and the highest temperature among them was recorded as the temperature at that time. A radiation thermometer (model IR-309, manufactured by Custom Co., Ltd.) was used to measure the combustion temperature.

[0037] Example 1 ignited in about 3 minutes without the need for air blowing, and produced very little ash after combustion. Example 2 ignited in about 3 minutes without the need for air blowing, burned at a higher temperature than Example 1, and produced very little ash after combustion.

[0038] In Comparative Example 1, ignition was difficult without blowing air, and ignition occurred in about 5 minutes when ignited while blowing air with a blower. After ignition, it burned stably at a higher temperature than in Example 2, and more ash remained after combustion compared to Examples 1 and 2. In Comparative Example 2, ignition occurred in about 3 minutes without the need for blowing air, it burned at a temperature similar to that of Example 1, and more ash remained after combustion compared to Examples 1 and 2. In Comparative Example 3, ignition occurred in about 3 minutes without the need for blowing air, the temperature during combustion fluctuated greatly, and more ash remained after combustion compared to Examples 1 and 2.

[0039] Example 1 has good ignition properties, can emit a scent according to the type of wood powder, burns at the same temperature as Comparative Example 2, and produces very little ash, making it easy to clean up after use. Example 2, while slightly inferior to Comparative Example 1, has a large calorific value, a high temperature during combustion, good ignition properties, and produces very little ash, making it easy to clean up after use.

[0040] In addition, a person skilled in the art can implement the present invention in a form in which various modifications are added to the above-described embodiment without departing from the spirit of the present invention, and the present invention includes such modifications.

Claims

1. A mixing step of forming a mixture by mixing 100 parts by mass of aggregate containing graphite powder and wood powder, in which the graphite powder is 30 to 50 parts by mass, with a binder containing carboxymethylcellulose or starch, and the binder is 3 to 15 parts by mass per 100 parts by mass of the aggregate; a kneading step of kneading the mixture at 110 to 200° C. while adding water to form a kneaded mixture; A method for producing briquettes, comprising a molding step of shaping the mixture into a product of a predetermined shape.

2. A method for producing molded charcoal as described in claim 1, characterized in that it includes a heat treatment process in which the molded product is heat treated at 700 to 1000°C in a non-oxidizing atmosphere.

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