KR102311318B1 - Coal briquettes, and method for manufacturing the same - Google Patents

Abstract

In an embodiment of the present invention, in an apparatus for manufacturing molten iron including i) a melter-gasifier in which reduced iron is charged, and ii) a reduction furnace connected to the melter-gasifier and providing reduced iron, it is charged into the dome of the melter and gasifier for rapid heating As a coal briquette to be used, it provides a coal briquette comprising raw coal, and a rice powder binder, wherein the damaged starch content in the rice powder binder is more than 5 wt%, a manufacturing method thereof, and an apparatus for manufacturing the coal briquettes.

Description

Coal briquettes, and manufacturing method thereof

It relates to coal briquettes, and a method for manufacturing the same. More specifically, it relates to coal briquettes to which a rice powder binder is applied, and a manufacturing method thereof.

In the smelting reduction ironmaking method, a reduction furnace for reducing iron ore and a melter-gasifier for melting the reduced iron ore are used. When iron ore is melted in the melter-gasifier, coal briquettes are charged into the melter-gasifier as a heat source to melt the iron ore. After the reduced iron is melted in the melter and gasifier, it is converted into molten iron and slag and then discharged to the outside. The coal briquettes charged into the melter-gasifier form a coal-packed bed. After oxygen is blown in through a tuyere installed in the melter-gasifier, the coal-packed bed is burned to produce combustion gas. The combustion gas is converted into a high-temperature reducing gas as it rises through the coal-packed bed. The high-temperature reducing gas is discharged to the outside of the melter-gasifier and is supplied to the reduction furnace as a reducing gas.

Coal briquettes are prepared by mixing pulverized coal and a binder and then compressing them. In order to be used for manufacturing molten iron, it is necessary to manufacture coal briquettes having excellent cold strength and hot strength. Therefore, the binder used for coal briquettes is required to have excellent adhesion and maintain high strength at high temperatures.

In the case of the binder used in the existing coal briquettes for manufacturing molten iron, corn starch containing more than 99% of starch on a dry basis is mainly used. However, in order to manufacture corn starch, it undergoes complex processes such as selection (removal of foreign substances), immersion (acid treatment), crushing, germ separation, okpi separation, and gluten separation. .

In order to solve the above problems, it is intended to provide a method for producing coal briquettes having excellent hot strength and cold strength by providing moisture content and grinding conditions that can secure the necessary adhesive force to use rice as a binder.

The coal briquettes according to an embodiment of the present invention are charged into the dome of the melter and gasifier in a molten iron manufacturing apparatus including a melter-gasifier in which reduced iron is charged, and a reduction furnace connected to the melter-gasifier and providing the reduced iron. As the rapidly heated coal briquettes, it includes raw coal, and a rice powder binder.

The damaged starch content in the rice powder binder may be more than 5% by weight.

The rice powder binder may be more than 3% by weight, based on 100% by weight of the total coal briquettes.

The starch content in the rice powder binder may be 85 to 95% by weight based on dry weight.

The amylose content in the starch may be 12 to 24 wt%.

The method for manufacturing coal briquettes according to an embodiment of the present invention comprises a melter-gasifier in which reduced iron is charged, and a reduction furnace connected to the melter-gasifier and providing the reduced iron, in the dome portion of the melter-gasifier. It is a method of manufacturing coal briquettes that are charged and heated rapidly.

The method for producing coal briquettes includes preparing raw coal, preparing a rice powder binder by adjusting the damaged starch content in rice powder to more than 5% by weight, and mixing the raw coal and the rice powder binder to prepare coal blends , gelatinizing the binder in the coal blend, and forming the coal blend.

The step of preparing coal blends by mixing the raw coal and the rice powder binder

With respect to 100% by weight of the total coal blended coal, it may be to mix the rice powder binder in an amount of more than 3% by weight.

The manufacturing of the rice powder binder may include drying the rice to adjust the moisture content, and pulverizing the rice whose moisture content is adjusted to adjust the particle size.

The step of adjusting the moisture content of the rice may be adjusting the moisture content to 10% by weight or less.

The step of adjusting the particle size of the rice powder may be pulverizing so that the average particle size of the rice powder is 20 to 100 μm.

The rice powder binder prepared in the step of preparing the rice powder binder may satisfy Equation 1 below.

[Formula 1] Water content of dried rice (% by weight) / Damaged starch content in the prepared rice powder binder (% by weight) < 0.92

The rice powder binder prepared in the step of preparing the rice powder binder may satisfy Equation 2 below.

[Formula 2] Prepared rice powder binder particle size (㎛) / Damaged starch content (wt%) in the prepared rice powder binder < 10

The rice powder binder prepared in the step of preparing the rice powder binder may have a maximum gelatinization viscosity of 300 cP or more at 30 to 95°C.

The step of gelatinizing the binder in the coal blend may be heat treatment by applying heat and moisture to the coal blend.

The heat treatment step may be performed at a temperature of 70 to 150° C. for 5 to 30 minutes.

According to an embodiment of the present invention, there is provided a coal briquette having excellent cold strength and hot strength using rice powder as a binder, and a method for manufacturing the same.

Specifically, by controlling the damaged starch content of the rice powder binder, it is possible to improve the viscosity of the binder and secure the strength of the coal briquettes.

It provides specific conditions that can control the damaged starch content of the rice powder binder.

Diversity in the supply and demand of binder raw materials can be secured, and the binder can be manufactured in a simple way, thereby reducing the cost of manufacturing coal briquettes.

1 shows the starch content of each of corn starch, rice flour, corn flour, and corn flour.
2 is a schematic diagram of a method for manufacturing coal briquettes according to an embodiment of the present invention.
3 is an SEM image at 5000 magnification of undamaged starch.
Figure 4 is a 5000x magnification SEM image of the damaged starch.
5 is a 5000 magnification SEM image of corn starch.
6 is a 5000 magnification SEM image of rice powder having an average particle size of 81 μm.
7 is a 5000 magnification SEM image of rice powder having an average particle size of 28 μm.
8 is a schematic diagram of an apparatus for manufacturing coal briquettes according to an embodiment of the present invention.
9 is a schematic diagram of an apparatus for manufacturing molten iron.
10 is a schematic diagram of an apparatus for manufacturing molten iron.
11 is a graph relating to starch gelatinization properties.

Hereinafter, embodiments of the present invention will be described in detail. However, this is provided as an example, and the present invention is not limited thereto, and the present invention is only defined by the scope of the claims to be described later.

The terminology used herein is for the purpose of referring to specific embodiments only, and is not intended to limit the present invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. The meaning of "comprising," as used herein, specifies a particular characteristic, region, integer, step, operation, element and/or component, and includes the presence or absence of another characteristic, region, integer, step, operation, element and/or component. It does not exclude additions.

In the present invention, the damaged starch means starch with damage to the particle surface. Such damage to the surface of the starch particles may occur due to mechanical damage to the surface of the starch grains during the milling process.

Although not defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Commonly used terms defined in the dictionary are additionally interpreted as having a meaning consistent with the related art literature and the presently disclosed content, and unless defined, are not interpreted in an ideal or very formal meaning.

The present invention relates to coal briquettes for manufacturing molten iron requiring high strength, and a method for manufacturing the same, wherein, instead of using pure starch as a binder, pulverized rice uses rice powder as a binder, and pure corn starch is applied as a binder; It relates to coal briquettes capable of securing equal or higher strength and quality, and a method for manufacturing the same.

Specifically, in order to use rice powder with a low starch content as a binder, by controlling the moisture content and the pulverized particle size to control the damaged starch content in the rice powder, a rice powder binder with easy viscosity expression is prepared and used as a binder. The present invention relates to coal briquettes for manufacturing molten iron having sufficient strength, and a method for manufacturing the same.

In the case of the binder used in the existing coal briquettes for manufacturing molten iron, corn starch containing more than 99% of starch on a dry basis is mainly used. However, in order to manufacture corn starch, complex processes such as selection (removal of foreign substances), immersion (acid treatment), pulverization, germ separation, husk separation, and gluten separation are required, and large-scale equipment is required and manufacturing cost increases.

In the case of rice, there are cases where it cannot be used for food due to long-term storage, or it must be discarded due to heavy metal contamination. .

However, in the case of rice, since it has a lower starch content than pure starch, there is a problem in that it is difficult to secure a sufficient level of strength of the coal briquettes when used as a binder for the coal briquettes for manufacturing molten iron.

The present invention can simplify the process required for binder manufacturing by manufacturing a rice powder binder by simply grinding rice. In addition, the rice used at this time is stored for a long time or by using raw materials that are not edible because they are contaminated with heavy metals, it is possible to reduce the cost of binders used in coal briquettes, and to stabilize supply and demand through diversification of raw materials. In addition, by changing the characteristics of the rice powder to facilitate the expression of adhesive strength, it is possible to secure the strength of the coal briquettes.

When rice is pulverized, the starch particles contained therein are physically damaged depending on the moisture content of the rice, the grinding method and the particle size, and the damage to the starch particles changes the gelatinization properties of the starch. In the present invention, the performance as a binder can be improved and the strength of coal briquettes can be secured by controlling the damaged starch content in the rice powder according to the control of the pulverized particle size and moisture content of the rice powder.

coal briquettes

Coal briquettes according to an embodiment of the present invention include raw coal, and a rice powder binder. The damaged starch content in the rice powder binder may be more than 5% by weight.

The damaged starch content may increase the moisture absorption rate of the starch, thereby increasing adhesion.

Starch does not dissolve in cold water, but in hot water it dissolves in gel form. It is not simply dissolved like sugar or salt, but goes through a process called alpha (α) or gelatinization. Starch originally has a semi-crystalline structure. When starch is placed in hot water, water permeates between the starch particles, causing the starch particles to swell and eventually collapse the semi-crystalline structure of the starch. At this time, the trapped amylose molecules are released from the starch particles, and when these amylose molecules are connected to each other, the viscosity of the starch solution increases and becomes sticky like glue. The damaged starch content in the rice powder binder may be more than 5% by weight. Specifically, the content of damaged starch is more than 5 wt%, and 30 wt% or less, more than 5 wt% and 25 wt% or less, more than 5 wt% and 20 wt% or less, 8 to 20 wt%, 10 to 20 wt%, 11 to 20% by weight, 14 to 20% by weight, 17 to 20% by weight. In this case, despite the low starch content compared to the conventional corn starch binder, excellent coal briquette strength can be secured. The higher the content of damaged starch in the rice powder binder, the better, but when it contains more than 5% by weight, strength similar to or higher than that of the conventional binder can be secured. When the damaged starch content is too low, the strength of the coal briquettes to which it is applied may be reduced, and if the damaged starch content is too high, it may be advantageous to secure the strength of the damaged starch briquettes, but economic feasibility may be lowered due to an increase in the binder manufacturing cost.

The rice powder binder may be more than 3% by weight, based on 100% by weight of the total briquettes. When the above range is satisfied, the strength of the coal briquettes can be secured. As the content of the binder increases, the strength of the coal briquettes may be improved, but the cost of the binder may increase and thus economic efficiency may be lowered. If the rice powder binder content is too small, the strength of the coal briquettes may be reduced. Specifically, it may be more than 3% by weight and not more than 10% by weight, 4 to 10% by weight, 4 to 8% by weight, or 4 to 7% by weight.

The starch content in the rice powder binder may be 85 to 95% by weight based on dry weight.

The amylose content in the starch may be 12 wt% or more. Specifically, it may be 12 to 24 wt%, 13 to 18 wt%, 13 to 17 wt%, or 14 to 16 wt%. In general, the higher the amylose content in the starch, the better the gelatinization and the adhesive force may increase. However, the starch content and the amylose content in the starch may vary depending on the type of grain, the type of rice, or whether it is improved. When the amylose content is 12 wt% or more, the strength of the coal briquettes can be secured. When the content of starch in the binder or the content of amylose in the starch is too small, the strength of the coal briquettes may decrease due to insufficient adhesion.

Starch content or amylose content may vary depending on the type of binder raw material grain.

In the case of rice, the amylose content may vary depending on the variety or whether it is improved. Journal Korean J. Food Cookery Sci. Vol. 29, No. Table 1 shows the approximate content of amylose in major varieties published in 6 (2013).

Amylose content (wt%) Hope 13.61 Ilmi 14.45 Koshihikari 13.16 Huitomebore 13.55 Mipum 16.53

However, this is for helping understanding of the invention, and does not mean that the variety or amylose content of the rice of the present invention is limited thereto.

The raw coal may be pulverized coal. As the pulverized coal, a raw material containing carbon, such as bituminous coal, subbituminous coal, anthracite, and coke, may be used.

1 is a measurement of the starch content in corn starch, rice powder, corn flour, and corn powder. It can be seen that the starch content of rice powder, corn flour, and corn powder is lower than that of corn starch. The higher the starch content, the higher the adhesive strength of the binder. Corn starch used as a conventional binder has a very high starch content of 99% by weight or more, but as shown in FIG. 1, rice powder has a lower starch content than corn starch, making it difficult to apply as a binder. .

In the present invention, although the starch content of the rice powder is relatively low, the content of damaged starch in the rice powder is high, the gelatinization properties of starch are changed, the adhesiveness of the binder is improved, and consequently the strength of the coal briquettes is improved.

The amylose content in the starch may vary depending on the type of rice, and the higher the amylose content in the starch, the higher the adhesive strength of the binder. When the amylose content in the starch is satisfied, the rice powder binder can secure sufficient adhesion by controlling the damaged starch content, and it is possible to secure the strength of the coal briquettes.

The moisture content in the coal briquettes may be 5 to 10% by weight. If the moisture content is too small, the strength of the coal briquettes may decrease, and if the moisture content is too high, the efficiency may decrease when used for manufacturing molten iron.

Since rice powder, not corn starch, is used in the coal briquettes according to an embodiment of the present invention, there may be differences in the contents of amylose and amylopectin in the separated starch binder. Corn starch generally has an amylose content of 25 to 31%, whereas rice powder has a lower amylose content than corn starch. In the case of short-grain rice, the amylose content is 12 to 24% by weight, specifically 13 to 18% by weight. By analyzing the amylose content of the starch binder separated from the coal briquettes, it is possible to distinguish between coal briquettes using corn starch as a binder and coal briquettes using rice powder as a binder.

Specifically, the content of damaged starch in the prepared coal briquettes can be determined by the following method. Coal and starch are physically separated, the starch content is measured, and the damaged starch content in the separated starch is measured.

The starch content can be determined using enzymatic digestion. First, the starch and coal in the coal briquettes are treated with a starch decomposing enzyme to decompose the starch, and then separated through a 5A to 5C filter to check the total starch content.

Next, for the measurement of the damaged starch content in the starch, the starch separated from coal was decomposed into maltodextrin using Fungal α-amylase, and the damaged starch content was measured using a damaged starch content measurement kit. When measured, the damaged starch content among the total starch content of the starch binder used in the coal briquettes can be determined.

How to make coal briquettes

It relates to a method for manufacturing coal briquettes in which reduced iron is charged and rapidly heated by being charged into a dome of the melter-gasifier in a molten iron manufacturing apparatus including a melter-gasifier connected to the melter-gasifier and a reduction furnace for providing the reduced iron .

2 schematically shows a sequence of a method for manufacturing coal briquettes according to an embodiment of the present invention.

The method for manufacturing coal briquettes according to an embodiment of the present invention includes the steps of i) preparing raw coal (S10), ii) adjusting the damaged starch content in the rice powder to more than 5% by weight to prepare a rice powder binder (S20), iii) mixing raw coal and the rice powder binder to prepare coal blended coal (S30), iv) gluing the binder in the coal blended coal (S40), and v) forming the coal blended coal (S50) include

The present invention can provide a method for manufacturing high-strength coal briquettes using rice having a low starch content as a binder by including the step (S20) of preparing a rice powder binder by adjusting the damaged starch content in the rice powder.

Specifically, the step of preparing a rice powder binder by adjusting the damaged starch content in the rice powder (S20) is a step of drying the rice to adjust the moisture content, and pulverizing the rice whose moisture content is adjusted to adjust the particle size. may include

In addition, it may include a step (S40) of gelatinizing the binder in the coal blend after the step (S30) of preparing the coal blend.

First, in the step of preparing the raw coal ( S10 ), pulverized coal may be used as the raw coal. As pulverized coal, a raw material containing carbon such as bituminous coal, subbituminous coal, anthracite, and coke may be used. The particle size of the pulverized coal can be adjusted to 4 mm or less. When the particle size of the pulverized coal is satisfied, mixability with the binder, uniformity, and handling may be improved, and the strength of the coal briquettes may be improved.

Next, a step (S20) of preparing a rice powder binder is performed by adjusting the damaged starch content in the rice powder to more than 5% by weight. Specifically, the content of damaged starch is more than 5 wt%, and 30 wt% or less, more than 5 wt% and 25 wt% or less, more than 5 wt% and 20 wt% or less, 8 to 20 wt%, 10 to 20 wt%, 11 to 20% by weight, 14 to 20% by weight, 17 to 20% by weight.

The damaged starch content in the rice powder binder may be adjusted according to the moisture content of the rice before grinding, the grinding temperature, the grinding particle size, and the type of grinder. In the case of damaged starch, it can be generated during the grinding process of grains, and by controlling the content of damaged starch, the temperature at which the viscosity develops during the coal briquettes manufacturing process is lowered, and the water-absorbing ability is improved to improve the water-binding power. increased, and the enthalpy for starch gelatinization is lowered, thereby improving the function as a binder for coal briquettes.

Therefore, the higher the damaged starch content in the rice powder, the more advantageous in terms of the adhesive strength of the binder and the strength of the coal briquettes.

3 shows an SEM image (magnification of 5000) of undamaged starch, and FIG. 4 shows an SEM image (magnification of 5000) of damaged starch. As shown in FIG. 4 , damaged starch means starch having damage to the starch surface, and such damage to the starch surface may improve water absorption into the starch. In the case of corn starch having a particle size of 14 μm in FIG. 5, the damaged starch content is only 1%, but in the case of the rice powder binder of FIGS. 6 and 7 prepared according to an embodiment of the present application, the content of damaged starch is 9.9% by weight. , it can be seen that the damaged starch content is remarkably high despite the larger particle size compared to corn starch at 17.2 wt%.

Since the portion having a small starch content in the outer shell is removed according to the degree of milling of the rice before milling, the degree of milling of the rice before milling may affect the components of the prepared rice powder binder. Specifically, rice that has been milled for 9 to 12 minutes can be used. In an embodiment of the present invention to be described later, a rice powder binder was prepared using rice polished for about 12 minutes.

Preparing the rice powder binder by adjusting the damaged starch content to more than 5 wt% (S20) may include drying the rice to adjust the moisture content, and pulverizing the rice to adjust the particle size.

In the step of controlling the moisture content by drying the rice, the moisture content may be adjusted to 10% by weight or less. According to the moisture content of the rice, the damaged starch content of the rice powder binder produced during the grinding process changes, which greatly affects the quality of the binder.

If the moisture content is too high, the damaged starch content in the rice powder binder obtained by the subsequent grinding process may be reduced. As the moisture content is lower, the damaged starch content may increase, but economic feasibility may be reduced due to an increase in the cost required for the process, and the risk of fire may increase during pulverization. Specifically, the moisture content of the rice may be 4 to 10% by weight or 5 to 10% by weight. Drying for controlling the moisture content may be performed by hot air or natural drying. In an embodiment of the present invention to be described later, moisture was controlled by drying in an oven at 80°C. At this time, the lower the moisture content, the better, but considering the fire risk and drying cost increase during pulverization, it was divided into 5%, 10%, and 14% (undried).

Next, the step of pulverizing the rice to adjust the particle size may be to control the grain size of the rice powder by pulverizing so that the average particle size of the rice powder is 20 to 100 μm. In the process of pulverizing rice to control the particle size, the content of damaged starch in the powder may increase. If the pulverized particle size is too small, the possibility of loss due to dust collection during the coal briquettes manufacturing process increases, and if it is too large, the dispersion degree of the binder may decrease, or the adhesive strength may be reduced due to the small amount of damaged starch in the prepared rice powder binder.

In the case of grinding, it can be carried out using a general grinder such as a pin mill, a blade mill, or a fine mill, and before fine grinding, a hammer mill or a roll mill (Roll Mill) can be carried out coarse grinding. The pulverization may be by dry pulverization, and it is possible to simplify and simplify the manufacturing process in that it does not require complicated process condition control, and the damaged starch content can be adjusted simply by dry pulverization. In the case of dry grinding, there is an advantage in that the moisture content of the rice adjusted in the previous step is not changed.

In an embodiment of the present invention, which will be described later, in order to find a range in which the quality of coal briquettes is easy to secure and the loss of dust collection during the process is not large, rice powder having an average particle size of 30 μm, 70 μm, 100 μm, and 200 μm is manufactured and binder performance is confirmed. did.

The rice powder binder prepared in the step (S20) of preparing the rice powder binder may have a starch content of 85 to 95% by weight based on dry weight, and an amylose content of 12 to 24% by weight in the starch. When the above range is satisfied, high-strength coal briquettes can be manufactured by using rice powder as a binder. Specifically, the amylose content in the starch may be 12 to 24 wt%, 12 to 24 wt%, 12 to 20 wt%, 12 to 18 wt%, 13 to 16 wt%, or 14 to 16 wt%. The rice powder binder satisfying the starch content and the amylose content in starch can secure the strength of coal briquettes when applied as a binder even if the amylose content is lower than that of the corn starch binder. This is because the rice powder binder contains damaged starch at a certain level or more.

In the step of preparing the rice powder binder, the prepared rice powder binder may satisfy Equation 1 below.

[Formula 1]

Moisture content of dried rice (% by weight) / Damaged starch content in the prepared rice powder binder (% by weight) < 0.92

When the above range is satisfied, coal briquettes having a level similar to or higher than that of coal briquettes using a conventional corn starch binder may be manufactured.

In the step of preparing the rice powder binder, the prepared rice powder binder may satisfy Equation 2 below.

[Formula 2]

Particle size of the prepared rice powder binder (㎛) / Damaged starch content (% by weight) in the prepared rice powder binder < 10

When the above range is satisfied, coal briquettes having a level similar to or higher than that of coal briquettes using a conventional corn starch binder may be manufactured.

The rice powder binder prepared in the step (S20) of preparing the rice powder binder may have a maximum gelatinization viscosity of 300 cP or more in a state of an 8% aqueous solution at a concentration of 30 to 95°C. Specifically, the maximum gelatinization viscosity at 30 to 95 ° C is 350 cP or more, 350 to 1000 cP, 350 to 800 cP, 400 to 800 cP, 400 to 764 cP, 600 to 800 cP, 700 to 800 cP, 760 to 800 cP, or 700 cP or more. When the maximum gelatinization viscosity range is satisfied, the strength of coal briquettes can be secured. When it is lower than the above range, the strength of the coal briquettes may decrease, or the manufacturing cost may increase due to an increase in the amount of binder required for manufacturing the coal briquettes. The higher the maximum gelatinization viscosity, the more advantageous, but when the maximum gelatinization viscosity is too high, the cost of the binder manufacturing process rises, thereby reducing economic feasibility, or attaching to the device may occur.

The rice powder binder prepared in the step of preparing the rice powder binder may have a gelatinization start temperature of 40 to 75 ℃. Specifically, the gelatinization initiation temperature may be 40 to 70 °C, 40 to 68.2 °C, 40 to 60 °C, or 50 to 60 °C.

When the gelatinization initiation temperature range and the maximum gelatinization viscosity range are satisfied at 30 to 95° C., there is an advantage that a conventional apparatus can be used.

Next, in the step (S30) of preparing coal blended coal by mixing the rice powder binder and the raw coal, the binder is added to the pulverized coal according to the determined ratio, and then the coal blend is uniformly mixed to prepare the coal blend.

In the step of preparing the coal blended coal (S30), the rice powder binder may be added and mixed in an amount of more than 3 wt%, and 7 wt% or less based on 100 wt% of the total coal blended coal.

If the amount of the binder is too small, the strength of the coal briquettes may be lowered, and if the amount of the binder is too large, problems such as adhesion to the device in the process of molding the mixture may occur, and economic feasibility due to the increase in the cost of the binder may be lowered.

In the step (S30) of preparing the coal blend, other types of binders such as rice powder binder and corn starch may be used together.

Next, the step of gelatinizing the binder in the coal blend (S40) may be performed. The step of gelatinizing the binder in the coal blend may be to increase the adhesive force through the gelatinization reaction between the moisture and the binder in the coal blend by heat-treating the coal blend.

The heat treatment may be to apply heat and moisture to the coal blended coal, or to supply steam to the coal blended coal.

The heat treatment may be performed at a temperature of 70 to 150 °C for 5 to 30 minutes. Specifically, it may be carried out for 5 to 20 minutes. When it satisfies the above range, by effectively gelatinizing the starch in the rice powder binder, it is possible to improve the binder adhesion and secure the strength of the coal briquettes.

Next, forming the coal blend (S50) is performed. The coal briquettes may be compressed by charging the mixture between a pair of rollers, thereby manufacturing coal briquettes in the form of pockets or strips. However, this is only an example of the present invention, and does not mean that it is limited to the above-described molding apparatus and molding form.

Drying the molded body may be further performed after the step (S50) of forming the coal blend, and drying is not limited to a drying method such as natural drying or hot air drying, and may be performed by an appropriate method.

coal briquette manufacturing device

The present invention relates to an apparatus for manufacturing coal briquettes which is charged into a dome of the melter and rapidly heated in a molten iron manufacturing apparatus including a melter-gasifier in which reduced iron is charged, and a reduction furnace connected to the melter-gasifier and providing the reduced iron. is about

The apparatus for manufacturing coal briquettes according to an embodiment of the present invention includes a raw coal supply bin (1), a rice supply bin (2), a drying device connected to the rice supply bin (2), and a drying device (3) for receiving and drying rice, the A grinding device (4) connected to a drying device and grinding the dried rice raw material to produce a rice powder binder, a rice powder binder supply bin (5) connected to the grinding device and storing a rice powder binder, the raw coal supply bin ( 1) and a mixing device 6 connected to each of the rice powder binder supply bins 5, mixing the raw coal and the rice powder binder to produce coal blended coal, and receiving the coal blended coal from the mixing device 6 and heat treatment and a molding device 8 for molding the blended coal for a kneader 7 to do so.

The kneader 7 may supply heat and moisture.

The kneader 7 is connected to a steam supply pipe, and may be to receive steam from the steam supply pipe to heat-treat the coal blend.

8 schematically shows an apparatus for manufacturing coal briquettes according to an embodiment of the present invention.

As shown in FIG. 8 , the coal briquettes manufacturing apparatus 60 includes a raw coal supply bin 1 and a rice supply bin 2 for storing raw coal, a drying device 3 for adjusting an appropriate moisture content, and dried raw materials. A pulverizing device (4) for pulverizing, a rice powder binder supply bin (5) for storing and supplying a rice powder binder, a mixing device (6) for mixing raw coal and rice powder binder, heat and heat to the mixture mixed in the mixer (6) It includes a kneader 7 for supplying moisture to impart adhesion, and a molding device 8 for manufacturing coal briquettes by molding the mixed mixture.

The molding device 8 compresses the mixture to manufacture coal briquettes. For example, the molding apparatus 8 may include a pair of rollers, and may manufacture pocket or strip-shaped coal briquettes by charging the mixture between the rollers and pressing the mixture.

9 schematically shows an apparatus 100 for manufacturing molten iron using coal briquettes manufactured according to the present embodiment. The structure of the apparatus 100 for manufacturing molten iron in FIG. 9 is merely to illustrate the present invention, and the present invention is not limited thereto. Accordingly, the molten iron manufacturing apparatus 100 of FIG. 9 may be modified in various forms.

The molten iron manufacturing apparatus 100 of FIG. 9 includes a melter-gasifier 10 and a packed-bed reduction furnace 20 . In addition, other devices may be included as needed. In the packed bed reduction furnace 20, iron ore is charged and reduced. The iron ore charged into the packed-bed reduction furnace 20 is pre-dried and then passed through the packed-bed reduction furnace 20 to be produced as reduced iron. The packed-bed reduction furnace 20 is a packed-bed reduction furnace, which receives a reducing gas from the melter-gasifier 10 and forms a packed layer therein.

Since the coal briquettes manufactured according to this embodiment are charged into the melter-gasifier 10 , a coal-packed layer is formed inside the melter-gasifier 10 . A dome portion 101 is formed in the upper portion of the melter and gasifier 10 . That is, a wider space is formed compared to other parts of the melter-gasifier 10, and there is a high-temperature reducing gas there. Therefore, the coal briquettes charged into the dome 101 by the high-temperature reducing gas are converted into char by a thermal decomposition reaction. The char produced by the thermal decomposition reaction of coal briquettes moves to the lower part of the melter-gasifier 10 and exothermicly reacts with oxygen supplied through the tuyere 30 . As a result, the coal briquettes can be used as a heat source for maintaining the melter-gasifier 10 at a high temperature. On the other hand, since char provides air permeability, a large amount of gas generated in the lower part of the melter-gasifier 10 and reduced iron supplied from the packed-bed reduction reactor 20 make the coal-packed bed in the melter-gasifier 10 easier and more uniformly. can pass

In addition to the above-described coal briquettes, bulk carbon material or coke may be charged into the melter-gasifier 10 as necessary. A tuyere 30 is installed on the outer wall of the melter and gasifier 10 to blow oxygen. Oxygen is blown into the coal packed bed to form a combustion zone. The coal briquettes may be combusted in the combustion zone to generate reducing gas.

10 schematically shows an apparatus 200 for manufacturing molten iron using coal briquettes manufactured according to the present embodiment. The structure of the molten iron manufacturing apparatus 200 of FIG. 10 is only for illustrating the present invention, and the present invention is not limited thereto. Therefore, the molten iron manufacturing apparatus 200 of FIG. 10 may be modified in various forms. Since the structure of the molten iron manufacturing apparatus 200 of FIG. 10 is similar to that of the molten iron manufacturing apparatus 100 of FIG. 9 , the same reference numerals are used for the same parts, and a detailed description thereof will be omitted.

As shown in FIG. 10 , the molten iron manufacturing apparatus 200 includes a melter-gasifier 10 , a fluidized-bed reduction furnace 22 , a reduced iron compression device 40 , and a compressed reduced iron storage tank 50 . Here, the compressed reduced iron storage tank 50 may be omitted.

The prepared coal briquettes are charged into the melter and gasifier 10 . Here, the coal briquettes generate a reducing gas in the melter-gasifier 10 , and the generated reducing gas is supplied to the fluidized-bed reduction reactor 22 . The powder iron ore is supplied to a plurality of reduction furnaces 22 having a fluidized bed, and is produced as reduced iron while flowing by the reducing gas supplied from the melter-gasifier 10 to the fluidized-bed reduction furnace 22 . Reduced iron is compressed by the reduced iron compression device 40 and then stored in the compressed reduced iron storage tank (50). The compressed reduced iron is charged together with the coal briquettes from the compressed reduced iron storage tank 50 to the melter-gasifier 10 and melted in the melter-gasifier 10 . Since the coal briquettes are supplied to the melter-gasifier 10 and change into char with air permeability, a large amount of gas generated from the lower part of the melter-gasifier 10 and compressed reduced iron make the coal-packed layer in the melter-gasifier 10 easier and more uniform. It is possible to provide good quality molten iron by passing through it.

Hereinafter, preferred examples and comparative examples of the present invention will be described. However, the following examples are only preferred examples of the present invention, and the present invention is not limited thereto.

Evaluation Example 1 - Evaluation of binder gelatinization properties

(Corn Starch (CS): Comparative Example 1 (CS)) As a comparative example, powdered corn starch was used. The corn starch has high purity with a dry (Dry) standard starch content of 99% or more. 5 shows a 5000 magnification SEM image of corn starch (CS). The measured average particle size of the corn starch binder (CS) was 14 μm, and the damaged starch content in the corn starch binder (CS) was approximately 1.0% by weight.

(Rice powder (RP): Experimental Example 1-1 (RP70), Experimental Example 1-2 (RP500)) Rice polished for about 12 minutes was used, the starch content was about 90 wt%, and the amylose content was about 15 The weight % of domestic short-grain seeds were used. After adjusting the moisture content to 10% by weight or less through a drying process, the particles were pulverized into 70 meshes (Experimental Example 1-1: RP70, 81㎛) and 500 meshes (Experimental Example 1-2: RP500, 28㎛). adjusted.

6 is a 5000 magnification SEM image of the rice powder binder Experimental Example 1-1 (RP70) prepared according to an embodiment of the present invention, and FIG. 7 is a 5000 magnification of the prepared rice powder binder Experimental Example 1-2 (RP500). SEM image.

The damaged starch content of the prepared rice powder binder Experimental Example 1-1 (RP70) and Experimental Example 1-2 (RP500) was 9.9% by weight and 17.2% by weight, respectively. It can be confirmed that the rice powder binder prepared according to an embodiment of the present invention has a higher content of damaged starch as the particle size is smaller. In addition, it can be seen that, despite having a larger particle size than the corn starch of Comparative Example 1 (CS), it has a higher content of damaged starch.

(Method for measuring damaged starch content) The prepared rice powder binder was measured at 40° C. using a Megazyme assay kit using Fungal α-amylase. Specifically, according to the method for measuring damaged starch provided by Megazyme, 50 Unit/ml of Fungal α-amylase was added to 100 mg of a sample containing damaged starch, and the damaged starch was treated with maltodextrins at 40°C. React for 10 minutes. Next, dilute sulfuric acid is added to terminate the reaction. After separation through centrifugation, 0.1 ml of amyloglucosidase solution was reacted with 0.1 ml of supernatant on the surface at 40° C. for 10 minutes, then 4.0 ml of GOPOD additive solution was added, followed by further reaction for 20 minutes. . Put it in a spectrophotometer and read the absorbance at 510 nm to determine the damaged starch content from the value compared with the absorbance of the standard sample.

(Method for measuring maximum gelatinization viscosity) The maximum gelatinization viscosity of the binder was measured using Brabender's Micro Visco-Amylo-Graph®-U, and the binder was made into an 8% aqueous solution and heated from 30℃ to 5℃ per minute. The maximum measured value among the viscosities up to the maximum temperature of 95°C was taken as the maximum viscosity.

When the maximum gelatinization viscosity during gelatinization of starch is too low, the binding force to the pulverized coal may be reduced, and thus the strength of the coal briquettes may be reduced.

Table 2 shows the components, content, particle size, and density of binders used in Experimental Examples and Comparative Examples.

binder type corn starch rice powder Comparative Example 1-1
(CS) Experimental Example 1-1
(RP70) Experimental Example 1-2
(RP500) Moisture (%, 110℃, 3hr) 9.6 10 4.5 starch content (wt%) Dry base 99.6 90.7 90.7 (wt%) Wet base 90.1 81.5 86.0 Damaged starch content (wt%) 1.0 9.9 17.2 starch component Amylose (wt%) 25.1 15.9 14.6 Amylopectin (% by weight) 74.9 84.1 85.4 granularity
(μm) Dx (10%) 7.9 11.5 6.26 Dx (50%) 14.2 61.3 22.1 Dx (90%) 21.9 181 51.9 average particle size 14.3 84 28 density
(g/cc) Bulk Density 0.498 0.637 0.531 Tap Density 0.701 0.887 0.807 Compressibility (%) 29.0 28.1 34.2 wet
analysis
(weight%) K ₂ O 0.0105 0.19 0.17 Na ₂ O 0.0243 0.011 0.011

11 is an experiment of gelatinization properties using the corn starch binder (CS) of Comparative Example 1 of Table 2 and the rice powder binder of Experimental Example 1-1 (RP70) and Experimental Example 1-2 (RP500) having different crushed particle sizes. .

11 , it can be seen that all of the experimental examples and comparative examples satisfy the range of 200 to 2000 cPs at 30 to 95°C. More specifically, in Experimental Example 1-1 (RP70) and Experimental Example 1-2 (RP500), it was confirmed that the maximum gelatinization viscosities at 30 to 95°C were 400 cP and 764 cP, respectively.

It was confirmed that Experimental Example 1-1 (RP70) had a slightly higher gelatinization initiation temperature and a slightly lower maximum gelatinization viscosity than Comparative Example 1 corn starch binder (CS). However, in the case of Experimental Example 1-1 (RP70) through Evaluation Example 2, which will be described later, it can be confirmed that it is possible to secure the necessary viscosity for application to the coal briquette binder.

It can be seen that in Experimental Example 1-2 (RP500), the gelatinization initiation temperature was lowered from 68.2°C to 52.3°C compared to the corn starch (CS) of Comparative Example 1, and the maximum gelatinization viscosity was increased from 590cPs to 764cPs. When applied as a binder to coal briquettes, sufficient viscosity can be secured, and when applied as a binder, sufficient viscosity can be secured even when gelatinized at a relatively low temperature, which can be an advantage in the manufacturing process of coal briquettes.

In addition, it can be seen from the experimental results that the starch gelatinization properties may vary depending on the pulverized particle size.

Evaluation Example 2 - Evaluation of cold strength of coal briquettes according to damaged starch content

(Production of coal briquettes) Prepare coal briquettes by mixing pulverized coal of 3.4 mm or less with a rice powder binder. As the pulverized coal, a mixture of hard coal, pulverized coke, and coke was used. As a binder, short-grain domestic rice, polished for about 12 minutes, is dried in an oven for a certain period of time to adjust the moisture content, and then pulverized to a constant particle size using a grinder. Rice powder containing 5 to 20 wt% of damaged starch was used to prepare a binder. Table 3 shows specific conditions of the binders used.

The particle size of rice powder was measured using HELOS particle size analyzer of Sympatec GmbH.

The damaged starch content of the rice powder was measured in the same manner as described in Evaluation Example 1 using a Megazyme assay kit using Fungal α-amylase at 40°C.

Next, the mixture was put into a kneader and heat was applied from the outside so that the moisture and binder dispersed in the coal blend increased adhesive strength through a gelatinization reaction. At the kneader temperature of 150°C, the residence time was constant at 15 minutes.

Next, the uniformly mixed mixture was charged between a pair of rolls to prepare coal briquettes. In this case, a pair of rolls pressurized the mixture at a pressure of 20 kN/cm to prepare a pillow-shaped coal briquettes having a size of 64.5 mm × 25.4 mm × 19.1 mm. The prepared coal briquettes were stored at room temperature for 1 hour and then their strength was measured.

Since the detailed manufacturing process of the remaining coal briquettes can be easily understood by those of ordinary skill in the art to which the present invention pertains, a detailed description thereof will be omitted.

(Experimental Example 2-1) The moisture content of the rice is dried to 5% by weight to prepare a rice powder binder having a particle size of about 30㎛, and 4.5% by weight of the rice powder binder is mixed based on 100% by weight of the coal blended coal, and then the coal briquettes are manufactured in the manner described above. did.

(Experimental Example 2-2) The moisture content of the rice is dried to 10% by weight to prepare a rice powder binder having a particle size of about 30㎛, and 4.5% by weight of the rice powder binder is mixed based on 100% by weight of the coal blended coal, and then the coal briquettes are manufactured in the above-described manner did.

(Experimental Example 2-3) The moisture content of the rice was dried to 5%, a rice powder binder having a particle size of about 70 μm was prepared, and 4.5 wt% of the rice powder binder was mixed based on 100 wt% of the coal blended coal, and then coal briquettes were prepared in the manner described above. .

(Experimental Example 2-4) The moisture content of the rice was dried to 10%, a rice powder binder having a particle size of about 70 μm was prepared, and 4.5 wt% of the rice powder binder was mixed based on 100 wt% of the coal blended coal, and then the coal briquettes were prepared in the manner described above. . (Experimental Example 2-5) After drying the moisture content of rice to 5% to prepare a rice powder binder having an average particle size of 96 μm, and mixing 4.5 wt% of the rice powder binder based on 100 wt% of coal blended coal, The coal briquettes were manufactured according to the method.

(Experimental Example 2-6) The moisture content of the rice was dried to 5%, a rice powder binder having a particle size of 31 μm was prepared, and 8% by weight of the rice powder binder was mixed based on 100% by weight of the coal blended coal, and then coal briquettes were prepared in the manner described above.

(Comparative Example 2-1) After mixing 4.5wt% of corn starch in the form of powder based on 100% by weight of coal blended coal, coal briquettes were prepared in the manner described above. (Comparative Example 2-2) After drying the moisture content of the rice to 5% by weight, preparing a rice powder binder having an average particle size of 193 μm, and mixing 4.5% by weight of the rice powder binder based on 100% by weight of the coal blend, The coal briquettes were prepared in the manner described above.

(Comparative Example 2-3) The moisture content of the rice was dried to 5% by weight, to prepare a rice powder binder having an average particle size of 31㎛, 3% by weight of the rice powder binder was mixed based on 100% by weight of the coal blend, and then the coal briquettes were prepared in the manner described above. . (Comparative Example 2-4) In a state where the moisture content of 14 wt% without drying the rice, a rice powder binder having an average particle size of about 100 μm was prepared, and after mixing 4.5 wt% of the rice powder binder based on 100 wt% of the coal blend , coal briquettes were prepared in the manner described above.

(Method for measuring the compressive strength of coal briquettes) The compressive load of the coal briquettes was measured as the maximum load when the coal briquettes were compressed at a speed of 50 mm/min, and was measured as the average value of 20 samples of the coal briquettes.

(Method for measuring the drop strength of coal briquettes) The quality of cold strength was evaluated by measuring the drop strength index of the prepared coal briquettes. The drop strength index was expressed as a weight percentage of a particle size of 20 mm or more after 2 kg of the prepared coal briquettes were free-falling 4 times from a height of 5 m.

division Comparative Example 2-1 Comparative Example 2-2 Comparative Example 2-3 Comparative Example 2-4 Experimental Example 2-1 Experimental Example 2-2 Experimental Example 2-3 Experimental Example 2-4 Experimental Example 2-5 Experimental Example 2-6 Grinding total moisture content (%) - 5 5 14 5 10 5 10 5 5 Binder particle size (㎛) 14 193 31 98 28 33 70 69 96 31 Damaged starch (wt%) One 3 19 5 20 17 14 11 10 19 Binder (wt%) 4.5 4.5 3.0 4.5 4.5 4.5 4.5 4.5 4.5 8.0 Calculation 1 - 1.67 0.26 2.80 0.25 0.59 0.36 0.91 0.50 0.26 Calculation 2 14 64.33 1.63 19.60 1.40 1.94 5.00 6.27 9.60 1.63 Compressive strength (kgf) 69 49 45 58 74 69 68 65 67 112 Drop strength (%) 81 63 55 76 85 83 83 81 80 98

In the case of Comparative Example 2-1, the strength test result of coal briquettes when conventional corn starch was used. When the compressive strength is 60kgf or more and the drop strength is 80% or more, the coal briquette strength suitable for manufacturing molten iron is secured.

In the case of Comparative Example 2-2, rice powder was used as a binder, but when the particle size of the powder was coarse to 200 μm, the content of damaged starch was as low as 3 wt %, and it was confirmed that the strength of coal briquettes was not secured.

In the case of Comparative Example 2-3, a high level of damaged starch content was exhibited through sufficient drying and pulverization, but it was confirmed that the strength of the coal briquettes was not secured because the amount of binder used was too small at 3 wt%.

In the case of Comparative Example 2-4, it was confirmed that the average particle size of the rice powder was 98㎛, but when pulverized with a high moisture content of 14% by weight, the damaged starch content was as low as 5% by weight, and it was confirmed that the standard coal briquette strength was not satisfied. can

In the case of Experimental Example 2-1 of the present invention, rice powder having an average particle size of 28 μm was prepared through fine grinding after drying the raw material rice before grinding to lower the moisture content, and this was blended in 4.5 wt%. In this case, the rice powder was able to secure a higher strength of coal briquettes compared to Comparative Example 1, although the starch content was lower than that of corn starch.

By comparing Experimental Examples 2-1 and 2-2 and Experimental Examples 2-3 and 2-4, the effect of moisture content before grinding can be confirmed on similar rice powder particle sizes. In both cases, it can be seen that even if the pulverized grain size is the same, if pulverization is performed under a low moisture content, the content of damaged starch increases and the strength of coal briquettes is increased compared to the same pulverized grain size.

In Experimental Example 2-5, the grain size of the rice powder is large, but if the damaged starch content is increased compared to Comparative Example 2-4 through drying before pulverization, a higher level of strength can be secured even at the binder mixing ratio.

By comparing Experimental Example 2-1 and Experimental Example 2-6, the strength of coal briquettes according to the binder content can be confirmed. In the case of Experimental Example 2-6, coal briquettes with significantly improved strength can be manufactured. However, since approximately twice as much binder is used as compared to Experimental Example 2-1 having similar conditions, the cost of the binder may increase.

Equation 1 is an expression showing the relationship between the moisture content (wt%) of the dried rice and the damaged starch content (wt%) in the prepared rice powder binder under the condition that the binder content in the coal blend exceeds 3 wt%.

In the case of Experimental Examples 2-1 to 2-6, it can be seen that the binder content in the coal blend is more than 3 wt%, the value of Equation 1 is less than 0.92, and sufficient strength of the coal briquettes can be secured. On the other hand, in Experimental Example 2-3, since the binder content is 3 wt% or less, it can be seen that the strength of the coal briquettes is low. In addition, in the case of Experimental Examples 2-1, 2-2, and 2-4, the binder content in the coal blend exceeds 3% by weight, but it can be seen that the value of Equation 1 is 0.92 or more.

Equation 2 is an expression showing the relationship between the particle size (㎛) of the prepared rice powder binder and the damaged starch content (% by weight) in the prepared rice powder binder under the condition that the binder content in the coal blend exceeds 3 wt%.

In the case of Experimental Examples 2-1 to 2-6, it can be seen that the binder content in the coal briquettes is more than 3 wt %, the value of Equation 2 is less than 10, and sufficient strength of the coal briquettes can be secured. On the other hand, in Experimental Example 2-3, since the binder content is 3% by weight or less, it can be seen that the strength of the coal briquettes is low even if the value of Equation 2 is less than 10. In addition, in the case of Experimental Examples 2-1, 2-2, and 2-4, the binder content in the coal blend exceeds 3 wt%, but it can be seen that the value of Equation 2 is 10 or more.

The present invention is not limited to the above embodiments, but can be manufactured in a variety of different forms, and those of ordinary skill in the art to which the present invention pertains can take other specific forms without changing the technical spirit or essential features of the present invention. It will be understood that it can be implemented as Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

1: Coal supply bin 2: Rice supply bin
3: drying device 4: crushing device
5: Rice powder binder supply bin 6: Mixing device
7: kneader 8: molding device
10: melter-gasifier 20: packed bed reduction furnace
22: fluidized bed reduction furnace 30: tuyere
40: reduced iron compression device 50: compressed reduced iron storage tank
100, 200: Molten iron manufacturing device

Claims (13)

a melter-gasifier in which reduced iron is charged, and
As coal briquettes connected to the melter and gasifier and charged into a dome of the melter and gasifier in a molten iron manufacturing apparatus including a reduction furnace for providing the reduced iron and rapidly heated,
It contains raw coal, and a rice powder binder,
The damaged starch content in the rice powder binder is more than 5% by weight,
The rice powder binder is more than 3% by weight, based on 100% by weight of the total coal briquettes,
The starch content in the rice powder binder is 85 to 95% by weight based on dry weight,
The amylose content in the starch is 12 to 24% by weight of coal briquettes.
delete delete a melter-gasifier in which reduced iron is charged, and
In an apparatus for manufacturing molten iron connected to the melter-gasifier and including a reduction furnace for providing the reduced iron,
As a method of manufacturing coal briquettes which are charged in the dome of the melter and gasifier and rapidly heated,
preparing raw coal;
preparing a rice powder binder by adjusting the damaged starch content in the rice powder to more than 5% by weight;
preparing coal blends by mixing the raw coal and the rice powder binder;
gelatinizing the binder in the coal blend; and
Comprising the step of molding the coal blend,
The step of preparing coal blends by mixing the raw coal and the rice powder binder
With respect to 100% by weight of the total blended coal, the rice powder binder is mixed in an amount of more than 3% by weight,
The starch content in the rice powder binder is 85 to 95% by weight based on dry weight,
The amylose content in the starch is 12 to 24 wt%, the method for producing coal briquettes.
delete 5. The method of claim 4,
The step of preparing the rice powder binder is
controlling the moisture content by drying the rice; and
A method for producing coal briquettes comprising the step of controlling the particle size by pulverizing the rice whose moisture content is controlled.
7. The method of claim 6,
The step of adjusting the moisture content of the rice is
A method for producing coal briquettes, wherein the moisture content is adjusted to 10% by weight or less.
7. The method of claim 6,
The step of adjusting the particle size of the rice powder is
The method for producing coal briquettes is to pulverize the rice powder to have an average particle size of 20 to 100 μm.
7. The method of claim 6,
In the step of preparing the rice powder binder
The prepared rice powder binder is a method for producing coal briquettes that satisfy the following formula 1.
[Formula 1]
Moisture content of dried rice (% by weight) / Damaged starch content in the prepared rice powder binder (% by weight) < 0.92
7. The method of claim 6,
In the step of preparing the rice powder binder
The prepared rice powder binder is a method for producing coal briquettes that satisfy the following formula 2.
[Formula 2]
Particle size of the prepared rice powder binder (㎛) / Damaged starch content (% by weight) in the prepared rice powder binder < 10
5. The method of claim 4,
In the step of preparing the rice powder binder
The prepared rice powder binder is a method for producing coal briquettes that is at least 300 cP maximum gelatinization viscosity at 30 to 95 ℃.
5. The method of claim 4,
The step of gelatinizing the binder in the coal briquettes is a method for producing coal briquettes that is heat-treated by applying heat and moisture to the coal briquettes.
13. The method of claim 12,
The heat treatment step
A method for producing coal briquettes performed at a temperature of 70 to 150° C. for 5 to 30 minutes.

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