KR101676629B1 - Coal briquettes and method for manufacturing the same - Google Patents

Abstract

There is provided a molten iron manufacturing apparatus including a melter-gasifier furnished with reduced iron and a reducing furnace connected to the melter-gasifier furnishing a reduced iron, the molten iron being charged into the dome of the melter- The method for producing a molded coal includes the steps of providing a mixture of a raw coal and a binder, applying a heat absorbing material to the surfaces of a pair of forming rolls adapted to mold the mixture, and charging the mixture between the pair of forming rolls, And compressing and molding the mixture by a pair of forming rolls to provide a molded carbon coated with the endothermic material. In the step of applying the endothermic material, the endothermic material is at least one material selected from the group consisting of metal hydroxides, limestone, and dolomite.

Description

TECHNICAL FIELD [0001] The present invention relates to a blanket,

And a method of manufacturing the same. More particularly, the present invention relates to a briquette coated with an endothermic material and not being well differentiated when introduced into a melter-gasifier, and a method for producing the same.

In the melt reduction steelmaking method, a melting furnace for melting iron ores and a reduced iron ore is used. When molten iron ore is melted in a melter-gasifier, molten coal is charged into the melter-gasifier as a heat source for melting iron ore. Here, the reduced iron is melted in a melter-gasifier, converted to molten iron and slag, and then discharged to the outside. The briquetted coal charged into the melter-gasifier furnishes a coal-filled bed. Oxygen is blown through the tuyere installed in the melter-gasifier, and then the coal-packed bed is combusted to generate combustion gas. The combustion gas is converted into a hot reducing gas while rising through the coal packed bed. The high-temperature reducing gas is discharged to the outside of the melter-gasifier and supplied to the reducing furnace as a reducing gas.

The briquettes charged in the melter-gasifier are charged into the melter-gasifier and can be easily differentiated while meeting with the high-temperature gas present in the melter-gasifier. When the molded fuel is differentiated at a high temperature, the combustion heat required for melting the reduced iron located in the lower portion of the melter-gasifier can not be provided. Therefore, since a large amount of briquettes must be used, the fuel cost rises and the amount of the fine particles in the melter-gasification furnace increases, thereby deteriorating the air permeability in the melter-gasifier.

And to provide a briquetted coal which is not well differentiated when it is introduced into a melter-gasifier. Further, it is intended to provide a method for producing the above-described molded charcoal.

The present invention relates to a method of manufacturing a molten steel that is charged into a dome of a melter-gasifying furnace and rapidly heated in a molten steel making furnace including a melter-gasifier furnished with reduced iron and a reducing furnace connected to the melter- (S20) of applying a heat absorbing material to a surface of a pair of forming rolls which are applied to form a mixture, and a step (S20) of applying a heat absorbing material to the surface of a pair of forming rolls Charging the mixture between a pair of shaping rolls, and pressing the mixture by a pair of shaping rolls to provide a molded carbon coated with a heat absorbing material (S30).

In the step of applying the endothermic material, the endothermic material may be at least one material selected from the group consisting of metal hydroxides, limestone and dolomite.

The amount of the endothermic material may be 3 wt% to 15 wt% of the molded carbon, and more specifically, the amount of the endothermic material may be 4 wt% to 8 wt% of the molded carbon.

In the step of providing the mixture, the binder may be at least one material selected from the group consisting of molasses, raw sugar, cellulose, starch and bitumen.

In the step of providing the mixture, the amount of the pulverized coal having a particle size of 5 mm or less contained in the coking coal may be 90 wt% to 100 wt%.

In the step of applying the endothermic material, the surfaces of the pair of forming rolls can be kept at room temperature.

In providing the mixture, the mixture may comprise from 3 wt% to 15 wt% binder and the balance cokes.

And a reducing furnace connected to the melter-gasifier for supplying reduced iron to the dome of the melter-gasifying furnace to rapidly heat the melter-gasifier. Examples of the molded bodys include a mixture of cyanide and a binder, and a heat absorbing material coated on the mixture.

The endothermic material may be one or more materials selected from the group consisting of metal hydroxides, limestone, and dolomite.

The amount of the endothermic material may be 3 wt% to 15 wt% of the molded carbon, and more specifically, the amount of the endothermic material may be 4 wt% to 8 wt% of the molded carbon.

The mixture may comprise from 3 wt% to 15 wt% binder and the balance cokes.

The briquettes coated with the endothermic material are charged into the melter-gasifier, so that the briquettes are not well differentiated in the melter-gasifier. Therefore, the combustion heat required for melting the reduced iron can be sufficiently provided to improve the fuel cost. Further, the gas permeability in the melter-gasifier can be improved.

Fig. 1 is a schematic flow chart of a method of manufacturing a briquette according to an embodiment of the present invention.
Fig. 2 is a photograph of the surface morphology of the formed briquettes formed at various temperatures of the hot gas.
Fig. 3 is a schematic partial perspective view of a molding apparatus for producing the molded charcoal of Fig. 1;
4 is a schematic cross-sectional view of a molding apparatus cut along line IV-IV in Fig.
FIG. 5 is a schematic view of a molten iron manufacturing apparatus using the shaped coal produced in FIG. 1. FIG.
Fig. 6 is a schematic view of another molten iron manufacturing apparatus using the briquettes produced in Fig. 1. Fig.

The terms first, second and third, etc. are used to describe various portions, components, regions, layers and / or sections, but are not limited thereto. These terms are only used to distinguish any moiety, element, region, layer or section from another moiety, moiety, region, layer or section. Thus, a first portion, component, region, layer or section described below may be referred to as a second portion, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified and that the presence or absence of other features, regions, integers, steps, operations, elements, and / It does not exclude addition.

Unless otherwise defined, 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 this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows a flow chart of a method of manufacturing a briquette according to an embodiment of the present invention. The flow chart of the method of manufacturing the briquette of Fig. 1 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the method of manufacturing the briquette can be variously modified.

As shown in FIG. 1, the method for producing molded carbon includes the steps of providing a mixture of a raw coal and a binder (S10), applying a heat absorbing material to the surface of a pair of forming rolls, And a step (S30) of charging the mixture between the pair of shaping rolls and pressing the mixture by a pair of shaping rolls to provide a molded carbon coated with the endothermic material. In addition, the method of manufacturing the briquette may further comprise other steps.

First, in step S10, a mixture obtained by mixing coke and a binder is provided. Pulverized coal can be used as the coking coal. In order to reduce variation in quality, it is desirable that the particle size of the pulverized coal is constant. As a specific criterion, pulverized coal having a particle size of 5 mm or less and 90 wt% to 100 wt% can be used.

The amount of water mixed into the pulverized coal can be kept at 2 wt% to 12 wt%. When the amount of water mixed in the pulverized coal is adjusted to the above-mentioned range, the moisture blocks the pores of the pulverized coal particles. As a result, since the binder can not penetrate into the pulverized particle and is present outside the pulverized particle, the pulverized coal particles can be bonded well to each other to efficiently improve the hot strength and the cold strength of the shaped coal. As the binder, molasses, raw sugar, cellulose, starch or bitumen can be used. The amount of binder may be from 3 wt% to 15 wt% of the mixture. If the amount of the binder is too small, the strength of the briquette may be deteriorated. In addition, when the amount of the binder is too large, problems such as adherence occur when the pulverized coal and the binder are mixed. Therefore, the amount of the binder is adjusted to the above-mentioned range.

On the other hand, the mixture may further contain 1 wt% to 5 wt% of a curing agent. As the hardening agent, calcium oxide, calcium hydroxide, calcium carbonate, cement, bentonite, clay or limestone can be used. When the amount of the curing agent is too small, the bonding strength between the binder and the curing agent does not sufficiently take place and the strength of the molded cement can not be sufficiently secured. In addition, when the amount of the curing agent is too large, the amount of ash in the briquette is increased, and the fuel can not sufficiently serve as a fuel in the melting-gasification furnace. Accordingly, the amount of the curing agent is appropriately controlled. When molasses is used as the binder and quicklime or slaked lime is used as the hardening agent, it is preferable to mix the hardening agent uniformly with the pulverized coal and then add the molasses. In this case, the saccharide bonding can improve the cold strength of the briquettes produced in the subsequent process.

Returning again to Fig. 1, in step S20, a heat absorbing material is applied to the surfaces of the pair of forming rolls for molding the mixture. Here, metal hydroxides, limestone or dolomite can be used as the endothermic material. As the metal hydroxide, aluminum hydroxide or magnesium hydroxide can be used. The endothermic material is coated on the surface of the molded body in a step S30 to be described later. When the briquettes are charged into the melter gasification furnace and reacted, the endothermic material coated on the surface of the briquette causes an endothermic reaction, thereby locally forming the surface of the briquette into a low temperature region. As a result, by lowering the reaction temperature, the particle diameter of the quartz becomes larger, the number of surface cracks decreases, and the number of quarts separated from the unit shaped coal decreases. This will be described in more detail with reference to FIG.

The blast furnace is charged into the melter-gasifier furnace and pyrolyzed at the upper part of the furnace bed by the hot gas coming from the lower part of the melter-gasifier furnace. At this time, the temperature of the high-temperature gas for pyrolyzing the briquette greatly affects the surface shape and the average particle diameter of the molded briquette.

Fig. 2 shows a photograph of the surface shape of the formed briquettes when the temperature of the hot gas is 900 ° C, 1000 ° C, and 1100 ° C, respectively. Fig. 2 (a) shows a photograph of the surface of the formed briquette formed at 900 DEG C, Fig. 2 (b) shows a photograph of the surface of the briquette formed at 1000 DEG C, and Fig. 2 This figure shows the surface photograph of the briquette formed.

As shown in Fig. 2, the lower the reaction temperature is, the larger the particle diameter of the molded product is. And the number of surface cracks decreases, and the number of cracks separated from the unit molded charcoal tends to decrease.

Since the endothermic material is coated on the surface of the briquettes according to an embodiment of the present invention, the endothermic material undergoes an endothermic reaction when placed in the melter-gasifier, thereby localizing the surface of the briquettes to a low temperature region. As a result, the reaction temperature of the blast furnace is lowered to increase the particle size of the blast furnace, the number of surface cracks decreases, and the number of blast furnaces separated from the unit blast furnace decreases.

Aluminum hydroxide, which is a heat absorbing material, undergoes a dehydration reaction together with an endothermic reaction at 180 ° C to 220 ° C, and magnesium hydroxide undergoes a dehydration reaction together with an endothermic reaction at about 330 ° C. The calcite reacts with the endothermic reaction at about 900 ° C, and the dolomite undergoes the first calcination reaction with the endothermic reaction at 650 ° C to 750 ° C, and the second calcination reaction occurs with the endothermic reaction at about 900 ° C . Through this endothermic reaction, the surface of the burnt carbon can locally be made into a low temperature region.

When the endothermic material is applied, the surfaces of the pair of forming rolls are kept at room temperature. More specifically, the surface temperature of a pair of forming rolls can be maintained at 20 ° C to 30 ° C. More preferably, the surface temperature of the pair of forming rolls can be maintained at 25 占 폚. If the surface temperature of the forming rolls is too high, the endothermic material may be vaporized before it is coated on the surface of the briquette.

Finally, in step S30, the mixture is charged into a pair of shaping rolls, and the mixture is compression-molded by a pair of shaping rolls to provide a molded carbon coated with a heat absorbing material. In this case, the amount of coated endothermic material may be between 3 wt% and 15 wt% of the shaped coal. If the amount of the endothermic material is too small, the briquette burrs into the melter-gasifier and is easily differentiated. Also, if the amount of the endothermic material is too large, the endothermic material is not coated on the molded carbon but remains on the outside. Therefore, the amount of the endothermic material is adjusted to the aforementioned range. More specifically, the amount of endothermic material may be from 4 wt% to 8 wt%.

Fig. 3 schematically shows a molding apparatus 100 for producing the molded charcoal of Fig. Figure 3 partially depicts the forming rolls 11 and 12, and for the sake of simplicity, the other parts are not shown.

The mixture is charged into a pair of forming rolls 11, 12 to which the heat absorbing material 10 is applied. A heat absorbing material 10 is applied to the concave grooves 111, 121 of the pair of forming rolls 11, 12. Thus, the mixture is press-molded by the pair of forming rolls 11 and 12 to produce molded-on-carbon coated with the heat absorbing material 10. [ As the pressurization is effected by a pair of shaping rolls 11, 12 as appropriate to compress the mixture, the surface of the briquettes is well coated with the endothermic material 10.

Fig. 4 schematically shows a sectional structure of the molding apparatus 100 cut along the line IV-IV in Fig. More specifically, FIG. 4 shows a process in which a molded product to which the heat absorbing material 10 is applied by the molding apparatus 100 is produced.

As shown in Fig. 4, the heat absorbing material 10 is sprayed from the nozzles provided on both sides of the pair of forming rolls 11 and 12. As a result, the heat absorbing material 10 is coated on the concave grooves 111 and 121 of the pair of forming rolls 11 and 12, respectively, rotating in mutually opposite directions.

A pair of forming rolls 11 and 12 compresses and forms the mixture to be charged therebetween. Accordingly, the surface of the briquettes compressed by the pair of forming rolls 11 and 12 is uniformly coated with the heat absorbing material 10. [ Therefore, it is possible to produce a molded carbon coated with a heat absorbing material.

Fig. 5 schematically shows an apparatus 200 for manufacturing molten iron using the shaped coal produced in Fig. The structure of the molten iron manufacturing apparatus 200 of FIG. 5 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the molten iron manufacturing apparatus 200 of FIG. 5 can be modified into various forms.

5, the molten iron manufacturing apparatus 200 includes a melter-gasifier 210, a fluidized bed reduction reactor 222, a reduced iron compactor 240, and a compacted iron storage tank 250. Here, the compressed reduced iron storage tank 250 may be omitted.

The produced briquettes are charged into a melter-gasifier (210) to form a coal-filled layer inside the melter-gasifier (210). Here, the blanket generates a reducing gas in the melter-gasifier 210, and the generated reducing gas is supplied to the fluidized-bed reduction reactors 222. The minute iron ores are supplied to a plurality of fluidized bed reduction reactors 222 having a fluidized bed and are made of reduced iron while flowing by the reducing gas supplied from the melter-gasifier 210 to the fluidized bed reduction reactors 222. The reduced iron is compressed by the reduced iron compactor 240 and then stored in the compressed reduced iron storage tank 250. The compressed reduced iron is supplied to the melter-gasifier 210 from the compressed-reduced iron storage tank 250 and melted in the melter-gasifier 210.

A dome portion 201 is formed on the upper portion of the melter-gasifier 210. That is, a wider space is formed compared with other portions of the melter-gasifier 210, and a high-temperature reducing gas is present therein. Therefore, the briquettes charged into the dome portion 201 by the high-temperature reducing gas can be easily differentiated. That is, since the briquettes are injected into the upper portion of the melter-gasifier maintained at 1000 캜, the briquettes undergo rapid thermal shock. Therefore, the blast furnace can be differentiated while moving to the lower portion of the melter-gasifier.

However, since the molded carbon produced by the method of FIG. 1 is coated with the endothermic material, the endothermic material locally lowers the temperature of the surface of the molded carbon through the endothermic reaction. Therefore, the briquetting coal is not differentiated in the dome portion 201 of the melter-gasifier 210 but drops to the lower portion of the melter-gasifier 210. The ozone produced by the pyrolysis reaction of the briquettes moves to the lower part of the melter-gasifier 210 and exothermically reacts with oxygen supplied through the ozone 230. As a result, the briquettes can be used as a heat source for keeping the melter-gasifier 210 at a high temperature. In the meantime, since the ladle provides air permeability, a large amount of gas generated in the lower portion of the melter-gasifier 210 and the reduced iron supplied from the fluidized-bed reduction reactor 222 make the coal-filled layer in the melter- It can pass.

The lump gasification furnace 210 may be charged with the lumpy carbonaceous material or the coke as needed in addition to the above-mentioned shaped coal. A tuyere (230) is installed on the outer wall of the melter-gasifier (210) to blow oxygen. Oxygen is blown into the coal packed bed to form a combustion zone. The briquettes can be burned in the combustion zone to generate reducing gas.

FIG. 6 schematically shows another molten iron manufacturing apparatus 300 using the shaped coal produced in FIG. The structure of the molten iron manufacturing apparatus 300 of FIG. 6 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the molten iron manufacturing apparatus 300 of FIG. 6 can be modified into various forms. Since the structure of the molten iron manufacturing apparatus 300 of FIG. 6 is similar to that of the molten iron manufacturing apparatus 200 of FIG. 5, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted.

The molten iron manufacturing apparatus 300 of FIG. 6 includes a melter-gasifier 210 and a packed-bed reduction reactor 220. In addition, the molten iron manufacturing apparatus 300 may include other apparatuses as required. In the packed-bed reduction reactor 220, iron ore is charged and reduced. The iron ore to be charged into the packed-bed reduction reactor 220 is pre-dried and then made into reduced iron by passing through the packed-bed reduction reactor 220. The packed-bed reduction reactor (220) receives a reducing gas from the melter-gasifier (210) and forms a packed bed in the furnace.

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

Experimental Example 1

Coal A having a mean particle size of 5 mm or less was prepared as raw coal. The properties of the coal A used are shown in Table 1 below.

Industrial analysis, dry base wt% Ashes (Ash) Volatile matter (VM) Fixed Carbon Coal A 9.1 25.1 65.8

8 parts by weight of molasses was added as a binder to uniformly mix coal A and molasses. 6.2 parts by weight of limestone as a heat absorbing material was applied to the surface of a pair of forming rolls. A pair of molding rolls coated with a heat absorbing material were charged with a mixture of coal A and a molasses mixture and compressed to prepare 100 parts by weight of pellets in the shape of pillows of 64.5 mm X 25.4 mm X 19.1 mm.

Experimental Example 2

6.5 parts by weight of dolomite was applied as a heat absorbing material to the surface of a pair of forming rolls. The remaining experimental procedure was the same as Experimental Example 1 described above.

Comparative Example 1

No endothermic material was applied to the surfaces of the pair of forming rolls. The remaining experimental procedure was the same as Experimental Example 1 described above.

Comparative Example 2

2 parts by weight of limestone as a hardening agent was further mixed into the coal A and molasses mixture, and the endothermic material was not applied to the surfaces of the pair of forming rolls. The remaining experimental procedure was the same as Experimental Example 1 described above.

Evaluation test of physical properties

In order to evaluate the briquettes produced according to Experimental Example 1, Experimental Example 2, and Comparative Example 1 and Comparative Example 2 described above, one briquette was charged into a rapid heating furnace maintained at a temperature of 1000 캜 and heat treated for 15 minutes, . Table 2 summarizes the total number of pieces of the obtained 촤 and the ratio of the pieces having a particle diameter of 13 mm or more among them.

Endothermic material
(Parts by weight) Total number of pieces
(Canned / molded) Percentage of pieces with a diameter of 13 mm or more (%) Experimental Example 1 Limestone
6.2 parts by weight 18 33.3 Experimental Example 2 dolomite
6.5 parts by weight 17 47.1 Comparative Example 1 - 22 27.3 Comparative Example 2 - 21 28.4

As shown in Table 2, the total number of filaments produced in the briquettes produced according to Experimental Example 1 was reduced compared to the total number of filaments produced in the briquettes produced according to Comparative Example 1 and Comparative Example 2, Of the total number of patients. In addition, it was found that the total number of scraps generated from the briquettes produced according to Experimental Example 2 was reduced compared to the total scraps generated from the briquettes produced according to the Comparative Example, and the proportion of sculptures having a diameter of 13 mm or more was increased.

As described above, it can be seen that the molded fuel according to an embodiment of the present invention can improve the fuel cost by sufficiently supplying the combustion heat required for melting the reduced iron without being well differentiated in the melter-gasifying furnace and improving the air permeability in the melter- I could.

It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the following claims.

10. Endothermic material
11. 12. Molding roll
111. 121. Concave groove
100. Molding device
210. Melting-gasification furnace
220. Packed bed type reduction furnace
222. A fluidized-bed reduction reactor
230. Tungus
240. Reduction iron compression unit
250. Compressed reduced iron storage tank
200, 300. Molten iron manufacturing equipment
201. Dome

Claims (11)

A melter-gasifier furnished with reduced iron, and
A reducing furnace connected to the melter-gasifier and supplied with a reducing gas from the melter-gasifier and providing the reduced iron to the melter-
Wherein the molten iron is charged into a dome portion of the melter-gasifying furnace and rapidly heated to generate a reducing gas,
Providing a mixture of a coking coal and a binder,
Applying a heat absorbing material to the surface of a pair of forming rolls adapted to form the mixture, and
Charging the mixture between the pair of shaping rolls and pressing the mixture by the pair of shaping rolls to provide a molded carbon coated with the heat absorbing material
Lt; / RTI >
Wherein the endothermic material is at least one material selected from the group consisting of metal hydroxides, limestone, and dolomite in the step of applying the endothermic material. The method according to claim 1,
Wherein the amount of the endothermic material is 3 wt% to 15 wt% of the briquette. 3. The method of claim 2,
Wherein the amount of the endothermic material is 4 wt% to 8 wt% of the briquette. The method according to claim 1,
Wherein the binder is at least one selected from the group consisting of molasses, raw sugar, cellulose, starch, and bitumen. The method according to claim 1,
In the step of providing the mixture, the amount of the pulverized coal having a particle size of 5 mm or less contained in the coking coal is 90 wt% to 100 wt%. The method according to claim 1,
Wherein the surface of the pair of forming rolls is kept at a normal temperature in the step of applying the heat absorbing material. The method according to claim 1,
In the step of providing the mixture, the mixture comprises 3 wt% to 15 wt% binder and the remaining cokes. A melter-gasifier furnished with reduced iron, and
A reducing furnace connected to the melter-gasifier and supplied with a reducing gas from the melter-gasifier and providing the reduced iron to the melter-
Wherein the molten steel is charged into a dome of the melting and gasifying furnace and rapidly heated to generate a reducing gas,
A mixture of a raw material and a binder, and
The endothermic material coated on the mixture
/ RTI >
Wherein said endothermic material is at least one material selected from the group consisting of metal hydroxides, limestone, and dolomite. 9. The method of claim 8,
Wherein the amount of the endothermic material is 3 wt% to 15 wt% of the briquette. 10. The method of claim 9,
Wherein the amount of the endothermic material is 4 wt% to 8 wt% of the briquette. 9. The method of claim 8,
Wherein the mixture comprises 3 wt% to 15 wt% of a binder and the balance cokes.

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