KR102151535B1 - Coal briquettes and method for manufacturing the same - Google Patents

Abstract

In a molten iron manufacturing apparatus including a melting gasifier into which reduced iron is charged according to an embodiment of the present invention, and a reduction furnace that is connected to the melting gasification furnace and provides the reduced iron, it is charged to the dome of the melting gasifier and heated rapidly. As a manufacturing method of coal briquettes, the steps of preparing pulverized coal, preparing a mixed powder by mixing pulverized coal and starch powder, preparing a mixed coal by mixing polyvinyl acetate with the mixed powder, and heat treating the mixed coal And forming the heat-treated coal briquettes to produce coal briquettes.

Description

Coal briquettes and their manufacturing method {COAL BRIQUETTES AND METHOD FOR MANUFACTURING THE SAME}

It relates to coal briquettes and a method of manufacturing the same. In detail, it relates to coal briquettes to which bioplastics with improved long-term storage are applied and a manufacturing method thereof.

In the melt-reduction steelmaking method, a reduction furnace for iron ore and a melting gasification furnace for melting the reduced iron ore are used. In the case of melting iron ore in the melting gasifier, coal briquettes are charged into the melting gasifier as a heat source for melting the iron ore. Here, the reduced iron is melted in the melting gasifier, converted into molten iron and slag, and then discharged to the outside. The coal briquettes charged in the melter gasifier form a coal filling layer. Oxygen is blown in through the windpipe installed in the melter and then burns the coal-filled bed to generate combustion gas. As the combustion gas rises through the coal-filled bed, it is converted into a high-temperature reducing gas. The high-temperature reducing gas is discharged to the outside of the melting gasifier and supplied to the reduction furnace as a reducing gas.

Coal briquettes are manufactured by mixing coal and a binder. In this case, molasses is used as the binder. The composition of molasses varies depending on the production area, and it is difficult to control the composition according to the sugar manufacturing process. Therefore, when manufacturing coal briquettes using molasses as a binder, the quality of the briquettes cannot be uniformly controlled. In particular, when molasses having high moisture is used, the quality of coal briquettes deteriorates.

It provides coal briquettes using bioplastics with improved long-term storage and a manufacturing method thereof.

A method for manufacturing coal briquettes according to an embodiment of the present invention is a molten iron manufacturing apparatus including a melting gasification furnace into which reduced iron is charged, and a reduction furnace connected to the melting gasification furnace and providing the reduced iron, the dome portion of the melting gasification furnace As a method of manufacturing coal briquettes charged and heated rapidly,

Preparing pulverized coal, mixing pulverized coal and starch powder to prepare a blended powder, preparing a blended coal by mixing polyvinyl acetate with the blended powder, heat treating the blended coal, and the heat-treated blending It may include the step of manufacturing coal briquettes by molding coal.

The starch powder may be an acid-treated starch powder.

The step of preparing the mixed powder may include mixing 1 to 10 parts by weight of acid-treated starch powder with respect to 100 parts by weight of pulverized coal.

The step of preparing the blended coal may be mixing by adding 0.5 to 4 parts by weight of polyvinyl acetate based on 100 parts by weight of the pulverized coal.

The polyvinyl acetate may be represented by the following formula (1).

[Formula 1]

The polyvinyl acetate may have a weight average molecular weight (Mw) of 100 to 5000.

In the step of preparing the blended coal, the step of adding an aqueous alcohol solution may be further included.

The aqueous alcohol solution may be mixed with 12.5 to 100 parts by volume of alcohol based on 100 parts by volume of water.

In the step of heat-treating the blended coal, the temperature of the blended coal may be performed at 50 to 100°C.

Steam is supplied in the step of heat treating the coal briquettes, and the amount of steam supplied when producing 50 tons of coal briquettes may be 1000kg/h or less.

The coal briquettes according to an embodiment of the present invention are charged to the dome of the melting gasifier in a molten iron manufacturing apparatus including a melting gasification furnace into which reduced iron is charged, and a reduction furnace connected to the melting gasification furnace and providing the reduced iron. As a coal briquette that is rapidly heated,

It may include 2 to 4% by weight of bioplastic, 1 to 4% by weight of polyvinyl acetate, 1 to 5% by weight of moisture, and the balance as coal.

It may include 2.5 to 3.5% by weight of the bioplastic, 1 to 2% by weight of polyvinyl acetate, 1 to 5% by weight of moisture, and the balance of coal.

The seonghyeongtan may have a drop strength reduction rate of less than 30% for a period of 30 days from the time of manufacture.

The coal briquettes may have a compressive strength of 20kgf or more.

The seonghyeongtan may have a falling strength of 60kgf or more.

According to an embodiment of the present invention, long-term storage properties of coal briquettes to which bioplastics are applied are improved.

In addition, according to an embodiment of the present invention, since there is no K component in the binder, clogging of the pipe does not occur.

In addition, according to an embodiment of the present invention, since quicklime or slaked lime is not used, the reactivity of CO ₂ is reduced, thereby improving the fuel efficiency of coal.

1 is a schematic flowchart of a method of manufacturing coal briquettes according to an embodiment of the present invention.
FIG. 2 is a schematic view of an apparatus for manufacturing coal briquettes to which the method for manufacturing coal briquettes shown in FIG. 1 is applied.
3 is a schematic view of a molten iron manufacturing apparatus using the coal briquettes manufactured in FIG. 1.
4 is a schematic diagram of another apparatus for manufacturing molten iron using the coal briquettes manufactured in FIG. 1.
5 is a graph showing the falling strength of coal briquettes of Example 1 and Comparative Example 1.
6 is a graph showing the solubility of polyvinyl acetate according to the mixing volume ratio of ethanol and water.
7 is a graph showing the strength of the seonghyeongtan according to the mass ratio of polyvinyl acetate and bioplastic content of the seonghyeongtan according to an embodiment of the present invention.
8 is a graph showing the discharged briquettes temperature according to the amount of steam used in the heat treatment step according to an embodiment of the present invention.

Terms such as first, second and third are used to describe various parts, components, regions, layers, and/or sections, but are not limited thereto. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, a first part, component, region, layer or section described below may be referred to as a second part, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for referring only to specific embodiments and is not intended to limit the present invention. Singular forms as used herein also include plural forms unless the phrases clearly indicate the opposite. The meaning of “comprising” as used in the specification specifies a specific characteristic, region, integer, step, action, element and/or component, and the presence of another characteristic, region, integer, step, action, element and/or component, or It does not exclude additions.

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

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

How to make coal briquettes

1 schematically shows a flow chart of a method of manufacturing coal briquettes according to an embodiment of the present invention. The flow chart of the method of manufacturing coal briquettes of FIG. 1 is for illustrative purposes only, and the present invention is not limited thereto. Therefore, the manufacturing method of coal briquettes can be variously modified.

As shown in FIG. 1, the method of manufacturing coal briquettes includes preparing pulverized coal, preparing a mixed powder by mixing pulverized coal and starch powder, preparing a compounded coal by mixing polyvinyl acetate with the mixed powder, And heat-treating the blended coal, and forming the heat-treated blended coal to manufacture the coal briquettes. In addition, if necessary, the method of manufacturing coal briquettes may further include other steps.

In the case of conventional bioplastic-applied coal briquettes, shrinkage occurs at a rapid rate as moisture is dried after manufacturing, and accordingly, elasticity decreases and is easily broken by external impact. In other words, there is a problem that it is difficult to store and use the existing bioplastic-applied coal briquettes for a long time after mass manufacturing.

However, the seonghyeongtan manufacturing method according to an embodiment of the present invention is a bioplastic applied seonghyeongtan with improved drop strength and long-term storage due to the elasticity of the acetate group by mixing polyvinyl acetate, so that the elasticity of the seonghyeongtan is maintained even after long-term storage. It is possible to manufacture.

The polyvinyl acetate may be represented by the following formula (1).

[Formula 1]

In the stage of preparing pulverized coal, pulverized coal is the crushed coal, and in general, coal is peat with carbon content of about 60%, peat and lignite of about 70%, sub-bituminous coal of about 70% to 80%, depending on the degree of carbonization. It is divided into 90% bituminous coal and 90% anthracite coal. The type of coal used here is not particularly limited, and a single coal type or various types of coal may be mixed and used. In order to reduce the variation in quality, it is preferable that the particle size of the pulverized coal is constant, and as a specific criterion, pulverized coal having a particle size distribution in which a particle size of 3 mm or less is 80 wt% or more, and a particle size of 3 mm or less is 90 wt% or more may be used.

The polyvinyl acetate may have a weight average molecular weight (Mw) between 100 and 5000, specifically 3000 to 4000.

When the weight average molecular weight of polyvinyl acetate is small, the strength of the coal briquettes may decrease, and when it is large, adhesion problems may occur.

Next, pulverized coal and starch powder are mixed to prepare a mixed powder.

The starch may be one containing at least one of amylose and amylopectin. Alternatively, the starch may be an acid-treated starch powder.

The acid-treated starch powder may be prepared by pulverizing biomass, treating the pulverized biomass with an aqueous acid solution, separating it into a filtrate containing starch, and drying the filtrate. After separating into a filtrate containing starch, the filtrate may be washed with a pH of 3 to 5.5. When the acid-treated starch powder is used, the moisture content in the coal briquettes may be reduced as a result.

The mechanism by which starch is converted into bioplastics is briefly described.

Amylose and amylopectin present in starch have a crystal structure.

Amylose is linear, and amylopectin has branches in the amylose structure. Heat is applied here and water is added to allow water to penetrate into the crystal. It is difficult for water to penetrate between the crystals at room temperature. Water penetrating through the crystals binds amylose and amylopectin through hydrogen bonding. Amylopectin is formed into amylose when the branches are cut by acid. When water penetrates the amylose crystal gap, hydrogen bonding occurs, and the hydrophilic OH group is directed outward and the hydrophobic C-C bond is directed inward due to the hydrophilic hydrophobic interaction, resulting in transformation into a helix structure. And it combines with the polar lipids present in the starch to form a double helix structure around the polar lipids. The helix that is not combined with the polar fat forms a double helix structure between the helixes. In the case of amylose, it is also shared as a double helix, and water is discharged to the outside and a crystal structure is formed.

The mechanism by which amylopectin changes to amylose is as follows. Amylose consists of an alpha 1,4-bonding of glucose. Amylopectin has a main backbone structure of 1,4-bonding, and its branch parts are connected to the skeleton structure through alpha 1,6-bonding.

Between pH 3 and 5.5 and temperatures above 60° C., alpha 1,4-bonding does not incise, whereas α-1,6-bonding does incision. Therefore, it is possible to selectively perform α-1,6-bonding incisions in the presence of acid. Therefore, it is possible to cut the branch of amylopectin and make it linear similar to amylose.

Through this process, a bioplastic consisting of 25 to 70% by weight of amylopectin and 30 to 75% by weight of amylose may be synthesized. More specifically, the bioplastic is composed of 25 to 35% by weight of amylopectin and 65 to 75% by weight of amylose. Bioplastics have a relatively high density, which increases the strength of coal briquettes, and linear molecules form a helix structure, enabling effective adhesion to the surface of pulverized coal.

The acid-treated starch powder may have an average particle size of 0.01 to 1 mm.

The step of preparing the mixed powder may include mixing 1 to 10 parts by weight of acid-treated starch powder with respect to 100 parts by weight of pulverized coal.

If less mixed, the strength of the coal briquettes may be lowered. Even if it is mixed a lot, there is a limit to improving the strength of the coal briquettes, and there is a concern that moisture present in the binder may deteriorate the quality of the coal briquettes.

The step of preparing the blended coal may be mixing by adding 0.5 to 4 parts by weight of polyvinyl acetate based on 100 parts by weight of the pulverized coal. Specifically, the polyvinyl acetate may be included in 1 to 3 parts by weight, 1 to 2.5 parts by weight, or 1.5 to 2 parts by weight.

When the content range is satisfied, both drop strength and compressive strength can be secured.

The step of preparing the blended coal may be carried out at a temperature of 50 to 65 °C. If the temperature is too high, the starch can be transformed into bioplastics before being mixed with polyvinyl acetate in the next step.

When the pulverized coal and starch are first mixed to form a mixed powder and then polyvinyl acetate is mixed, uniform mixing is possible.

The step of preparing the blended coal may further include adding an aqueous alcohol solution. The aqueous alcohol solution may include one paper phase selected from ethanol or methanol.

When an aqueous alcohol solution is added in the step of preparing the blended coal, the solubility of polyvinyl acetate is increased, so that the binder can be evenly distributed.

The aqueous alcohol solution may be 12.5 to 100 parts by volume of alcohol based on 100 parts by volume of water. If the alcohol content is high, the strength of the coal briquettes may decrease, and if the alcohol content is low, the problem of uneven distribution of the binder may occur. It may be a mixture of alcohol and water in a volume ratio of 1:8 to 1:1. Specifically, 1:8 to 1:2, 1:8 to 1:3, 1:8 to 1:4, 1:8 to 1:5, 1:8 to 1:6, or 1:8 to 1: May be 7.

Next, the step of heat-treating the blended coal may be supplying steam to increase the temperature.

Starch is converted into bioplastics during the heat treatment of the coal blend.

In the step of heat-treating the blended coal, the temperature of the blended coal may be 50 to 100°C. Specifically, it may be 80 to 90 ℃.

When the temperature is low, sufficient energy cannot be supplied, so that starch cannot be converted to bioplastic, and the strength of the manufactured coal briquettes may decrease. If the temperature is high, the binder may decompose.

The amount of steam supplied in the step of heat-treating the blended coal may be 1000kg/h or less when producing 50 tons of coal briquettes. Specifically, it may be 400 kg/h to 800 kg/h. If the amount of steam supplied is large, the heat treatment temperature increases, and if the amount of steam is small, the binder is not melted, which may cause uneven distribution.

After the step of heat-treating the blended coal, it may further include drying the heat-treated blended coal. By further including the step of drying it is possible to control the moisture present in the blended coal.

After the step of heat-treating the coal briquettes, the step of manufacturing the coal briquettes by molding the heat-treated coal briquettes may be performed.

A mixture may be charged between twin rolls rotating in opposite directions to prepare a pocket-shaped or strip-shaped briquette. As a result, it is possible to manufacture coal briquettes having excellent strength and a desired shape.

After the step of manufacturing the coal briquettes, it may further include drying the coal briquettes. By further including the step of drying, the strength of the coal briquettes may be improved by controlling moisture present in the coal briquettes.

Coal briquettes

The coal briquettes according to an embodiment of the present invention may include 2 to 4% by weight of bioplastic, 0.5 to 4% by weight of polyvinyl acetate, 1 to 6% by weight of moisture, and coal as a balance. Specifically, the bioplastic may include 2.5 to 3.8% by weight, 2.5 to 3.5% by weight, or 2.9 to 3.3% by weight, and polyvinyl acetate may include 1 to 2.4% by weight, or 1 to 2% by weight. . If the above range is satisfied, both drop strength and compressive strength can be secured.

The seonghyeongtan according to an embodiment of the present invention may have a dropping strength reduction rate of less than 30% for a period of 30 days after manufacture from the time of manufacture. Specifically, the fall strength reduction rate may be more than 0% and less than 20%, more than 2% and less than 15% or more than 0% and less than 10%.

Briquettes according to an embodiment of the present invention have excellent elasticity and improved long-term storage even after a certain period of time after manufacture due to the elasticity of the acetate group.

Briquettes according to an embodiment of the present invention may have a compressive strength of 20kgf or more. Specifically, it may be 20kgf or more and 80kgf or less, 25kgf or more and 75kgf or less, 30kgf or more and 70kgf or less, 30kgf or more and 60kgf or less, 50kgf or more and 60kgf or less, or 55kgf or more and 60kgf or less.

The seonghyeongtan according to an embodiment of the present invention may have a fall strength of 60% or more. Specifically, it may be 50% or more and 95% or less, 60% or more and 90% or less, 70% or more and 90% or less, 80% or more and 90% or less, or 85% or more and 90% or less.

As described above, the coal briquettes according to an embodiment of the present invention have excellent elasticity and strength even after a certain period of time after manufacture.

2 schematically shows an apparatus for manufacturing coal briquettes to which the method for manufacturing coal briquettes shown in FIG. 1 is applied. The structure of the apparatus for manufacturing coal briquettes of FIG. 2 is for illustrative purposes only, and the present invention is not limited thereto. Accordingly, the apparatus for manufacturing coal briquettes of FIG. 2 can be modified in various forms.

The coal briquette manufacturing apparatus includes bins 10, 20, and 40. Beans 10 and 20 supply pulverized coal and starch powder. The bins 10 and 20 are connected to the mixer 30, and the pulverized coal and starch supplied from the bins 10 and 20 are mixed in the mixer 30. At this time, the mixer 30 maintains a temperature of 80 ~ 90 ℃ to manufacture the mixed powder.

The mixer 30 is connected to the mixer 50 and mixes the mixed powder supplied from the mixer 30 and the polyvinyl acetate supplied from the polyvinyl acetate supply bin 40 to produce a blended coal. At this time, the mixer 50 may maintain a temperature of 50 to 65°C.

The mixer 50 is connected to the kneader 60, and the blended coal supplied from the mixer 50 may be stirred through the kneader 60 for a certain period of time to perform heat treatment. At this time, the temperature of the blended coal in the kneader 60 is stirred while maintaining a temperature of 50 to 100°C, and the starch in the blended coal can be transformed into bioplastic. It may be stirred in the kneader 60 for 3 minutes or more. In this case, as a means for increasing the temperature, the temperature of the kneader 60 may be increased through steam.

The blended coal heat-treated in the kneader 60 is supplied to the molding machine 70 and formed into a coal briquette. The molding machine 70 can be operated at -5℃ or higher. More specifically, it can be operated at room temperature.

3 schematically shows a molten iron manufacturing apparatus 200 using the coal briquettes manufactured in FIG. 1. The structure of the apparatus 200 for manufacturing molten iron in FIG. 3 is for illustrative purposes only, and the present invention is not limited thereto. Accordingly, the apparatus 200 for manufacturing molten iron of FIG. 3 may be modified in various forms.

The molten iron manufacturing apparatus 200 of FIG. 3 includes a melting gasification furnace 110 and a reduction furnace 120. In addition, other devices may be included as necessary. Iron ore is charged and reduced in the reduction furnace 120. The iron ore charged to the reduction furnace 120 is made of reduced iron while passing through the reduction furnace 120 after being pre-dried. The reduction furnace 120 is a packed bed type reduction furnace, receiving reducing gas from the melting gasifier 110 and forming a packed bed therein.

Since the coal briquettes manufactured by the manufacturing method of FIG. 1 are charged into the melting gasifier 110, a coal filling layer is formed inside the melting gasifier 110. A dome 101 is formed on the upper part of the melting gasification furnace 110. That is, a wider space is formed compared to other parts of the melter gasifier 110, and there is a high-temperature reducing gas. Therefore, the coal briquettes charged into the dome 101 can be easily differentiated by the high-temperature reducing gas. However, since the coal briquettes manufactured by the method of FIG. 1 have excellent strength, they are not differentiated from the dome of the melting gasifier 110 and fall to the bottom of the melting gasifier 110. The char generated by the pyrolysis reaction of the coal briquettes moves to the lower portion of the melting gasifier 110 and reacts exothermicly with oxygen supplied through the air vent 130. As a result, coal briquettes can be used as a heat source for maintaining the melting gasification furnace 110 at a high temperature. On the other hand, since char provides ventilation, a large amount of gas generated in the lower part of the melting gasifier 110 and the reduced iron supplied from the reduction furnace 120 can more easily and uniformly pass through the coal-filled layer in the melting gasifier 110. I can.

In addition to the above-described coal briquettes, bulk carbon materials or coke may be charged into the melter gasifier 110 as necessary. A blow hole 130 is installed on the outer wall of the melter gasifier 110 to inject oxygen. Oxygen is blown into the coal-filled bed to form a combustion zone. Coal briquettes can be burned in a combustion zone to generate reducing gas.

4 schematically shows a molten iron manufacturing apparatus 300 using the coal briquettes manufactured in FIG. 1. The structure of the apparatus 300 for manufacturing molten iron of FIG. 4 is only for illustrating the present invention, and the present invention is not limited thereto. Therefore, the molten iron manufacturing apparatus 300 of FIG. 4 can be modified in various forms. Since the structure of the apparatus for manufacturing molten iron 300 of FIG. 4 is similar to that of the apparatus 200 for manufacturing molten iron of FIG. 3, the same reference numerals are used for the same parts, and detailed descriptions thereof are omitted.

As shown in FIG. 4, the molten iron manufacturing apparatus 300 includes a melting gasification furnace 110, a reduction furnace 122, a reduced iron compression device 140, and a compressed reduced iron storage tank 150. Here, the compressed reduced iron storage tank 150 may be omitted.

The manufactured coal briquettes are charged into the melting gasifier 110. Here, the coal briquettes generate a reducing gas in the melting gasifier 110, and the generated reducing gas is supplied to the fluidized bed type reduction furnace. Powdered iron ore is supplied to a plurality of reduction furnaces 122 having a fluidized bed, and is made of reduced iron while flowing by the reducing gas supplied from the melting gasifier 110 to the reduction furnaces 122. The reduced iron is compressed by the reduced iron compression device 140 and then stored in the compressed reduced iron storage tank 150. The compressed reduced iron is supplied from the compressed reduced iron storage tank 150 to the melting gasifier 110 and melted in the melting gasifier 110. Since the coal briquettes are supplied to the melting gasification furnace 110 and transformed into char with ventilation, a large amount of gas and compressed reduced iron generated in the lower portion of the melting gasification furnace 110 make the coal filling layer in the melting gasification furnace 110 easier and more uniform. It can pass through to produce high-quality molten iron.

Hereinafter, the present invention will be described in more detail through experimental examples. These experimental examples are only for illustrating the present invention, and the present invention is not limited thereto.

Experimental Example 1: Evaluation of falling strength of coal briquettes

(Example 1 Manufacture of coal briquettes) 20 kg of coal having average properties and a particle size of 4 mm or less and 90% was prepared as pulverized coal. 3 parts by weight of acid-treated starch powder and 3 parts by weight of polyvinyl acetate are prepared based on 100 parts by weight of pulverized coal.

100 parts by weight of pulverized coal and 3 parts by weight of acid-treated starch powder are mixed at 90°C for 15 minutes to form a mixed powder, and 3 parts by weight of the mixed powder and polyvinyl acetate are mixed for 15 minutes at a temperature of 90°C or higher. Was prepared. The blended coal was supplied to a kneader and stirred at 80-90°C for 15 minutes, and then coal briquettes were manufactured using a press roll.

(Comparative Example 1 Preparation of coal briquettes) Except for adding polyvinyl acetate in Example 1, briquettes were prepared in the same manner.

In order to check whether the elasticity is improved even after long-term storage of the coal briquettes according to an embodiment of the present invention, the drop strength was measured from 1 hour to 30 days after manufacture, and the results are shown in FIG. 5.

The drop strength is calculated by the following formula after dropping 2kg of coal briquettes repeatedly 8 times from a height of 5m.

Falling strength (%) = (Weight of coal briquettes with a size of 10 mm or more / weight before test) *100

In the case of Comparative Example 1, the drop strength remained constant until 7 days after manufacture, and after that, the drop strength started to decrease rapidly, and at the time of 30 days, the drop strength was approximately 30%.

On the contrary, in the case of Example 1, it was confirmed that the drop strength remained almost unreduced until 30 days elapsed after manufacture.

In the case of coal briquettes using starch as a binder, since the elasticity of the coal briquettes decreases as the starch dries, the falling strength of the briquettes according to the passage of time is greatly reduced. However, in the case of the briquettes according to an embodiment of the present invention, polyvinyl acetate is mixed during manufacture, It can be seen that even after long-term storage, the elastic force can be maintained, so that the dropping strength hardly decreases.

Experimental Example 2: Evaluation of the solubility of polyvinyl acetate

According to an embodiment of the present invention, an aqueous alcohol solution may be added to improve the solubility of polyvinyl acetate in the manufacturing step of the blended coal.

In order to confirm the effect of this, the polyvinyl acetate solubility was tested by using ethanol, which is a type of alcohol, while varying the mixing volume ratio of ethanol and water, and is shown in FIG. 6.

After mixing water in 100 ml of ethanol in the following ratio, passing through a filter paper to dry the remaining undissolved mass was evaluated as (Rockinyang-Nameunyang)/Rockinyang *100 to evaluate the solubility.

6, when the mixing volume ratio of ethanol and water is 1:20, 1:18, 1:14, and 1:10, it appears that the solubility increases little by little as the ratio of water decreases, but when the mixing ratio is 1:8 It was confirmed that the solubility increased more than twice as compared to the case of 1:10. This is because acetate dissolves well under conditions in which water and ethanol are properly mixed.

Experimental Example 3: Evaluation of the strength of seonghyeongtan according to the mass ratio of the contents of polyvinyl acetate and bioplastic in the prepared seonghyeongtan

In order to evaluate the strength of seonghyeongtan according to the content of polyvinyl acetate, seonghyeongtan was prepared by varying the blending amount of polyvinyl acetate and having different content ratios of polyvinyl acetate and bioplastic.

Coal 20kg pulverized coal having an average property of less than 4mm and a particle size of 90% or more was prepared. To 100 parts by weight of pulverized coal, acid-treated starch powder and polyvinyl acetate were prepared as shown in Table 1 below.

According to the blending table of Table 1 below, 100 parts by weight of pulverized coal and acid-treated starch powder were mixed at room temperature for 5 minutes to form a mixed powder, and the mixed powder and polyvinyl acetate were mixed at room temperature for 5 minutes to prepare a blended coal. . The blended coal was supplied to a kneader and stirred at 80 to 90°C for 15 minutes, and then coal briquettes of Examples 2 to 5 were prepared using a press roll.

Mixing amount when manufacturing coal briquettes Ingredient content in coal briquettes Content ratio in coal briquettes Pulverized coal
(100 parts by weight) Starch
(Part by weight) Polyvinyl acetate
(Part by weight) Pulverized coal
(weight%) Bioplastic (% by weight) Polyvinyl acetate
(weight%) Polyvinyl acetate: Bioplastic
(Weight ratio) Example 2 100 parts by weight 4 One 95 3.8 One 8:2 Example 3 100 parts by weight 3.5 1.5 95 3.3 One 7:3 Example 4 100 parts by weight 3 2 95 2.9 1.9 6:4 Example 5 100 parts by weight 2.5 2.5 95 2.5 2.4 5:5

The compressive strength (kgf) and dropping strength (%) of the coal briquettes of Examples 2 to 5 were measured and shown in FIG. 7.

Compressive strength (kgf) means resistance to weight per unit. Measure the maximum load until the seonghyeongtan is destroyed by applying a constant pressure to the top of the coal briquettes placed on the measuring device.

The drop strength (%) was measured in the same manner as described in Experimental Example 1.

Referring to FIG. 7, as the content of polyvinyl acetate decreases, the compressive strength increases, but the drop strength decreases. Securing the drop strength and compressive strength, and considering both the cost aspect, in the case of 7:3 and 6:4, it is possible to obtain coal briquettes having excellent strength characteristics, and it is judged to be advantageous in terms of manufacturing cost.

Experimental Example 4: Temperature measurement of the discharged coal according to the amount of steam used in the heat treatment step

According to an embodiment of the present invention, the temperature of the coal blended in the heat treatment step may be 50 to 100°C, and it has been described above that if the temperature is too high, a problem of decomposition of the binder may occur.

In this experiment, in order to check the amount of steam supply required to maintain the temperature of the coal blended at 50 to 100°C in the heat treatment step, 20 tons of the blended coal were injected into the kneader, and the discharged coal briquettes were discharged according to the amount of steam used. The temperature was measured. The results are shown in FIG. 8.

It can be seen that in order for the temperature of the coal briquettes discharged based on 50% of the latent heat utilization rate of steam to be 50 to 100° C., steam of 800 kg/h or less must be supplied.

However, in general, since the latent heat utilization rate of steam is less than 50%, it can be seen that the temperature of the blended coal can be properly maintained in the heat treatment step when the steam of 1000 kg/h or less is supplied.

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

10 Pulverized coal supply bin 20 Starch powder supply bin 30 Mixer
40 Polyvinyl acetate supply bin 50 Mixer
60 Kneader 70 Molding machine 61 Steam supply pipe
100 Briquette manufacturing equipment 101. Dome 110. Melting gasification furnace
120,122. Reduction furnace 130. Punggu 140. Reduced iron compression device
150. Compressed reduced iron storage tank 200, 300. Molten iron manufacturing equipment

Claims (15)

A melting gasifier into which reduced iron is charged, and
A reduction furnace connected to the melting gasification furnace and providing the reduced iron
As a method for manufacturing coal briquettes charged to the dome of the melter and rapidly heated in a molten iron manufacturing apparatus comprising a,
Preparing pulverized coal;
Mixing pulverized coal and acid-treated starch powder to prepare a mixed powder;
Preparing a blended coal by mixing polyvinyl acetate with the mixed powder;
Heat-treating the blended coal; And
Including; forming the seonghyeongtan by molding the heat-treated blended coal
The coal briquettes have a drop strength reduction rate of less than 30% for a period of 30 days after manufacture,
How to make coal briquettes.
delete The method of claim 1,
The step of preparing the mixed powder
Mixing 1 to 10 parts by weight of acid-treated starch powder based on 100 parts by weight of pulverized coal
How to make coal briquettes.
The method of claim 1,
The step of preparing the blended coal; The
To the mixing by adding 0.5 to 4 parts by weight of polyvinyl acetate based on 100 parts by weight of the pulverized coal,
How to make coal briquettes.
The method of claim 1,
The polyvinyl acetate is
It is represented by the following formula 1,
How to make coal briquettes.
[Formula 1]

The method of claim 1,
The polyvinyl acetate is
The weight average molecular weight (Mw) is 100 to 5000
How to make coal briquettes.
The method of claim 1,
In the step of preparing the blended coal;
Further comprising the step of adding an aqueous alcohol solution
How to make coal briquettes.
The method of claim 7,
The aqueous alcohol solution is
12.5 to 100 parts by volume of alcohol based on 100 parts by volume of water
How to make coal briquettes.
The method of claim 1,
In the step of heat treating the blended coal
The temperature of the coal blend is carried out at 50 to 100 ℃
How to make coal briquettes.
The method of claim 1,
Steam is supplied in the step of heat treating the blended coal,
When producing 50 tons of coal briquettes, the amount of steam supplied is 1000kg/h or less.
How to make coal briquettes.
A melting gasifier into which reduced iron is charged, and
A reduction furnace connected to the melting gasification furnace and providing the reduced iron
As the coal briquettes charged to the dome of the melting gasification furnace and rapidly heated in a molten iron manufacturing apparatus comprising a,
2 to 4% by weight of bioplastic, 1 to 4% by weight of polyvinyl acetate, 1 to 5% by weight of moisture, and coal as the balance,
The seonghyeongtan has a drop strength reduction rate of less than 30% for a period of 30 days after manufacture from the time of manufacture,
Seonghyeongtan.
The method of claim 11,
2.5 to 3.5% by weight of the bioplastic, 1 to 2% by weight of polyvinyl acetate, 1 to 5% by weight of moisture, and coal as the balance
Seonghyeongtan.
delete The method of claim 11,
The coal briquettes have a compressive strength of 20kgf or more.
Seonghyeongtan.
The method of claim 11,
Dropping strength of more than 60kgf
Seonghyeongtan.

Images