WO2014098413A1 - Coal briquette and production method therefor - Google Patents

Abstract

Provided is a production method for coal briquettes which are charged into and rapidly heated in the dome part of a melting and gasification furnace, into which reduced iron is charged, in a molten iron production device comprising the melting and gasification furnace and a reduction furnace which is connected to the melting and gasification furnace and to which the reduced iron is provided. The production method for coal briquettes comprises the steps of i) providing pulverized coal, ii) producing a mixture obtained by the mixing of between 1 and 5 parts by weight of a hardening agent and between 5 and 15 parts by weight of a binder with respect to 100 parts by weight of the pulverized coal, and iii) moulding the mixture. In the step of providing the pulverized coal, the pulverized coal comprises i) more than 0 and no more than 50 wt% of low-grade coal, and ii) a balance of coal ash. The low-grade coal has between 25 wt% and 40 wt% of a volatile fraction (dry basis) and has a crucible swelling number of more than 0 and less than 3.

Description

Coal briquettes and manufacturing method thereof

The present invention relates to coal briquettes and a method of manufacturing the same. More specifically, the present invention relates to coal briquettes containing low grade coal and a method of manufacturing the same.

In the molten iron reduction method, iron ore is used as a reducing furnace and a molten gasifier for melting the reduced iron ore. When iron ore is melted in a melt gasifier, coal briquettes are charged into a melt gasifier as a heat source for melting iron ore. Here, the reduced iron is melted in the molten gasifier, converted to molten iron and slag and then discharged to the outside. The coal briquettes charged into the melt gasifier form a coal filling layer. Oxygen is blown through the tuyere installed in the melt gasifier and then burns the coal packed bed to produce combustion gas. Combustion gas is converted into hot reducing gas while rising through the coal-filled bed. The high temperature reducing gas is discharged to the outside of the melt gasification furnace and supplied to the reduction furnace as reducing gas.

Coal briquettes can be produced using bituminous coal. Bituminous coal is very low in coal, while bituminous coal is not produced in Korea. Therefore, all of the bituminous coal required for manufacturing molten iron is imported from overseas. Since most bituminous coals are produced only in some countries, such as Australia, Canada, and the United States, high-quality bituminous coal used for metallurgy is gradually depleted, resulting in supply and demand imbalances and fluctuating prices.

An object of the present invention is to provide a method for producing coal briquettes containing low quality coal.

Method for producing coal briquettes according to an embodiment of the present invention, the molten gas in which the reduced iron is charged, and is connected to the molten gasifier in the molten iron manufacturing apparatus including a reducing furnace for providing reduced iron is charged in the dome portion of the molten gasifier Is rapidly heated. The process for producing coal briquettes includes the steps of i) providing pulverized coal, ii) mixing 1-5 parts by weight of a curing agent and 5-15 parts by weight of a binder with respect to 100 parts by weight of pulverized coal, and iii) forming a mixture. Steps. In the step of providing pulverized coal, pulverized coal comprises i) low grade coal which is greater than 0 and 50 wt% or less, and ii) the remaining coal ash. Low quality coal has a volatility (dry basis) of 25 wt% to 40 wt% and has a crucible expansion index of greater than 0 and less than 3.

In the step of providing pulverized coal, the anhydrous baseline gross calorific value may be 5,500 Kcal / kg to 7,000 Kcal / kg. In the step of providing pulverized coal, a carbon source additive greater than 0 and up to 20 wt% may be added to the pulverized coal. The carbon source additive may include one or more carbon sources selected from the group consisting of powdered coke, coke dust, graphite, activated carbon and carbon black. The amount of the first carbon included in the carbon source additive may be greater than the amount of the second carbon included in the carbonaceous material.

In the step of providing pulverized coal, the amount of low-grade coal may be 10wt% to 40wt%. More preferably, the amount of low quality coal may be 15wt% to 30wt%.

In the step of preparing the mixture, the curing agent may be at least one material selected from the group consisting of quicklime, slaked lime, limestone, calcium carbonate, cement, bentonite, clay, silica, silicate, dolomite, phosphoric acid, sulfuric acid and oxides. In the step of preparing the mixture, the binder may be one or more materials selected from the group consisting of molasses, bitumen, asphalt, coal tar, pitch, starch, water glass, plastics, polymer resins and oils.

Since coal briquettes are manufactured using low grade coal, the production cost of the coal briquettes can be greatly reduced. In addition, the use of low-grade coal can increase the area of resource utilization.

1 is a schematic flowchart of a method of manufacturing coal briquettes according to an exemplary embodiment of the present invention.

FIG. 2 is a schematic diagram of an apparatus for manufacturing molten iron using the coal briquettes manufactured in FIG. 1.

3 is a schematic diagram of another apparatus for manufacturing molten iron using the coal briquettes manufactured in FIG. 1.

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

The terminology used herein is for reference only to specific embodiments and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the meaning of "comprising" embodies a particular characteristic, region, integer, step, operation, element and / or component, and the presence of other characteristics, region, integer, step, operation, element and / or component It does not exclude the addition.

Unless defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Commonly defined terms used are additionally interpreted to have a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted in an ideal or very formal sense unless defined.

As used herein, the term "hole" is to be interpreted to include all shapes that are drilled or dug in the form of points, lines or faces. Thus, a "hole" includes both shapes formed as holes or shaped like channels.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Figure 1 schematically shows a flow chart of a method for producing coal briquettes according to an embodiment of the present invention. The flowchart of the manufacturing method of the coal briquette of FIG. 1 is only for illustration of this invention, Comprising: This invention is not limited to this. Therefore, the manufacturing method of the coal briquettes can be variously modified.

As shown in FIG. 1, the method for producing coal briquettes includes the steps of i) providing pulverized coal, ii) mixing 1-5 parts by weight of a curing agent and 5-15 parts by weight of a binder with respect to 100 parts by weight of pulverized coal. And iii) molding the mixture. In addition, if necessary, the method of manufacturing coal briquettes may further include other steps.

First, in step S10, pulverized coal is provided. Pulverized coal includes low grade coal and the remaining coal ash. The amount of volatile matter contained in the pulverized coal is 20wt% to 35wt%. If the amount of volatile matter is too small, coal briquettes made of pulverized coal cannot be charged into a molten gasifier to produce a sufficient amount of reducing gas for the reduction of iron ore. In addition, when the amount of volatile matter is too large, the coal briquettes charged into the molten gasifier are easily differentiated, so that the heat source necessary for melting the reduced iron charged into the molten gasifier cannot be sufficiently secured. Therefore, the amount of volatile matter is adjusted to the above-mentioned range.

Coal can be classified in various ways. The criteria for coalification can be used for the classification of coal. Coalization degree refers to a process in which plant volatile matter decreases and the amount of fixed carbon increases as time, pressure, and temperature change underground. Coal can be classified as follows according to the degree of coalification. That is, coal has a carbon content (dry ash free basis) of less than about 60% peat, about 60 ~ 70% lignite, about 70 ~ 75% sub-bituminous coal, about 75 ~ 85% depending on the degree of coalification. It is divided into bituminous coal and anthracite coal of about 85% to 94%.

On the other hand, coal may be classified into coking coal and non-coking coal depending on the coking property. Coking bituminous coal has the property that coal particles bind to each other when dry. Coking property means that when coal is heated, it shows thermosoftening property and flow phenomenon around 350 ~ 400 ℃ and coal particles are bonded to each other and expand by pyrolysis gas generation and exhibit shrinkage phenomenon by solidification around 450 ~ 500 ℃. The coking property is evaluated by a free swelling index (FSI) by the Coal-Crucel Expansion Index Measurement (KS E ISO 501), which measures coal's expansion characteristics by heating coal to a final temperature of 820 W 5 ° C. Coal with a crucible expansion index of 3 or more is classified as coking coal, and coal with a crucible expansion index of less than 3 is classified as non-coking coal.

Coking bitumen is mainly used for metallurgy for coke production. On the other hand, non-coking coal has no binding capacity between the coal particles, so the coke quality is reduced when used for the production of coke was not used for metallurgy. Therefore, lignite, sub-bituminous coal, and non-caking bituminous coal, which are non-caking coal and have a high volatile content, have been mainly used for power generation. On the other hand, anthracite coal, which is non-coking coal, and has high fixed carbon and calorific value, has been mainly used in pulverized coal injection (PCI).

Low-grade coal is non-coking coal having a crucible expansion index (FSI) of less than 3, which means low-cost coal having a high volatile content. Low quality coal has been pulverized into pulverized coal and used for power generation. In one embodiment of the present invention, low-cost coal is used that is not used as metallurgical coal.

The coal briquettes charged into the melt gasifier are rapidly heated to 30 ° C./min or more in direct contact with a hot gas stream of about 1000 ° C. in a dome located at the top of the melt gas furnace. As the heating rate increases, the softening zone rises to high temperatures and the flow rate increases rapidly. Non-caking coal that does not melt at extremely low heating rates of 3 ° C./min also melts at rapid heating rates. When the viscosity change is large with respect to the temperature of coal, and the tar particles are large and the heating rate is high, the flow rate changes with the release of the tar, and the oxygen is high and crosslinking easily occurs at a low heating rate. As a result, the fluidity of coal increases by rapid heating. Therefore, soft melting occurs by rapid heating even when melting is not easy.

Since metallurgical coke is manufactured by heating at a low rate of 3 ° C./min, high flowability of coal itself can be used to produce high quality coke. Therefore, in the case of using low-cost, low-quality coal having low cohesiveness and fluidity, the quality of the coke is deteriorated. In contrast, the coal briquettes are rapidly heated to 30 ° C./min or more in direct contact with a hot gas stream of about 1000 ° C. in the dome section of the melt gasifier. Therefore, coal briquettes can be manufactured using low-cost, low-cost coal, which could not be used in the manufacture of metallurgical coke. For example, power generation coal can be used as a low grade coal.

The pulverized coal forming the coal briquettes charged into the melt gasifier determines the behavior of the melt gasifier. Therefore, only pulverized coal with limited properties can be used in the melt gasifier. Here, the pulverized coal must satisfy various conditions in terms of cold strength, hot strength, high temperature differentiation rate, ash content and fixed carbon amount. On the other hand, good quality coal can be produced by mixing coal for quality control with a high average reflectance to pulverized coal, but there is a problem that the cost of manufacturing coal briquettes increases.

The amount of low quality coal may be greater than zero and less than or equal to 50 wt%. If the amount of low-grade coal is too large, the quality of the coal briquettes to be produced is deteriorated, so the coal briquettes are well differentiated at high temperatures, the coal briquette strength is lowered, and the operation of the molten gasifier may become unstable. Therefore, the quantity of low quality coal is adjusted to the above-mentioned range. Preferably, the amount of low grade coal may be 10 wt% to 40 wt%. More preferably, the amount of low-grade coal may be 15wt% to 30wt%.

Anhydrous base high calorific value of low-grade coal may be 5,500 Kcal / kg to 7,000 Kcal / kg. The calorific value indicates the amount of heat released when a unit mass of coal is completely burned. The calorific value is measured by the KS E3707 standard and is represented by the gross calorific value on the anhydrous basis. Among the bituminous coals mainly used for metallurgy, hard coking coal having a high coking force has a high calorific value of about 7,500 Kcal / kg or more, and uncoal coal has a calorific value of 7,000 Kcal / kg to 7,500 Kcal / kg. Metallurgical coal has a high calorific value of more than 7,000 kcal / kg, while low-grade coal has 25 wt% to 40 wt% of volatile matter (dry basis), crucible expansion index greater than 0 and less than 3 and 5,500 Kcal / kg to 7,000 Kcal / It has a low calorific value of kg.

If the volatile matter content of the low-grade coal is too high, when the coal briquettes are charged into the molten gasifier, the volatile components contained in the coal briquettes are rapidly released to differentiate the coal briquettes. As a result, the operation of the melt gasification furnace may become unstable. Coking coal having a high crucible expansion index among coals having a volatile content of less than 25% is an expensive high-quality coal mainly used for metallurgy for coke production. On the contrary, non-coking coal having a low crucible expansion index is anthracite coal mainly used in pulverized coal blowing processes and is a coal having a high calorific value. Accordingly, there is no coal having a low volatile content and a low crucible expansion index and a low calorific value in the low-grade coal.

Coal with a high crucible expansion index can be used for coke production and is traded at high prices. If coal with high crucible expansion index is used for power generation, coal is expanded as the temperature rises in the process of blowing pulverized coal and the blowing nozzle is blocked. Therefore, only non-caking coal can be used for power generation or pulverized coal injection process so that the crucible expansion index is larger than 0 and less than 3 so that the blowing nozzle is not blocked during blowing.

If the calorific value of the low grade coal is too low, sufficient heat amount for melting the reduced iron when the coal briquettes are charged into the melt gasifier cannot be secured. In addition, although low-grade coal having a high calorific value may be used, non-coking coal having a high calorific value has a low volatile content as anthracite coal mainly used in pulverized coal blowing processes. Therefore, there is no coal having high calorific value as non-coking coal having a volatile matter content (dry basis) of 25% to 40% in low-grade coal and having a low crucible expansion index. Therefore, the calorific value of low-grade coal is maintained in the above-mentioned range.

On the other hand, to the pulverized coal can be added a carbon source additive of greater than zero and 20wt% or less. As the carbon source additive, powdered coke, coke dust, graphite, activated carbon or carbon black may be used. Here, the amount of the first carbon included in the carbon source additive may be greater than the amount of the second carbon included in the carbonaceous material. Therefore, the amount of fixed carbon of the coal briquettes can be increased by the carbon source additive.

That is, low-grade coal has a high volatile matter content and the content of fixed carbon is less than that of bituminous coal, and thus it cannot be used to manufacture molten iron. When the coal briquettes containing such low-grade coal are used in a molten gasifier, the amount of reducing gas generated by the coal briquettes is large, but the amount of coal produced is relatively low. In this case, more coal briquettes have to be put into the melt gasifier in order to supply sufficient amount of coal to the melt gasifier. In this case, the reducing gas is in a surplus state, but since the amount of coal used per tonne of molten iron is increased, the cost of manufacturing molten iron increases. Therefore, the carbon source additive having a high carbon content is partially mixed with the pulverized coal to secure the amount of fixed carbon required for the coal briquettes.

Next, a mixture of 1 to 5 parts by weight of a curing agent and 5 to 15 parts by weight of a binder is prepared based on 100 parts by weight of pulverized coal in step S20. As the hardener, quicklime, hydrated lime, limestone, calcium carbonate, cement, bentonite, clay, silica, silicate, dolomite, phosphoric acid, sulfuric acid, or an oxide may be used. If the amount of the curing agent is too small, the compound bonding of the binder and the curing agent does not sufficiently occur, and the strength of the coal briquettes cannot be sufficiently secured. In addition, when the amount of the curing agent is too large, the ash in the coal briquettes increases, so that it cannot play a sufficient role as fuel in the molten gasifier. Therefore, the amount of curing agent is adjusted to the above-mentioned range.

As the binder, molasses, bitumen, asphalt, coal tar, pitch, starch, water glass, plastic, polymer resin or oil may be used. On the other hand, when the amount of the binder is too small, the strength of the coal briquettes may deteriorate. In addition, when the amount of the binder is too large, problems such as adhesion during the mixing of the pulverized coal and the binder occur. Therefore, the amount of binder is adjusted to the above range.

In addition, a hardening | curing agent and a binder can arbitrarily set the mixing order. Therefore, the curing agent may be mixed with pulverized coal and then a binder may be mixed therein or the binder may be mixed with pulverized coal and then the curing agent may be mixed therein.

Finally, in step S30, the mixture is molded. Although not illustrated in FIG. 1, the coal briquettes in the form of pockets or strips may be manufactured by charging a mixture between paired rolls rotating in opposite directions. As a result, coal briquettes having excellent hot strength and cold strength can be produced.

FIG. 2 schematically shows an apparatus for manufacturing molten iron 100 using the coal briquettes manufactured in FIG. 1. The structure of the apparatus for manufacturing molten iron 100 of FIG. 2 is merely for illustrating the present invention, but the present invention is not limited thereto. Therefore, the apparatus for manufacturing molten iron 100 of FIG. 2 may be modified in various forms.

The molten iron manufacturing apparatus 100 of FIG. 2 includes a melt gasifier 10 and a reduction furnace 20. In addition, other devices may be included as needed. Iron ore is charged and reduced in the reduction furnace 20. Iron ore charged into the reduction furnace 20 is made of reduced iron while passing through the reduction furnace 20 after being pre-dried. Reduction furnace 20 is a packed-bed reduction reactor, receives a reducing gas from the melt gasifier 10 to form a packed bed therein.

Since the coal briquettes manufactured by the manufacturing method of FIG. 1 are charged into the molten gasifier 10, a coal filling layer is formed inside the molten gasifier 10. The dome part 101 is formed in the upper part of the melt gasifier 10. That is, a wider space is formed than the other parts of the melt gasifier 10, where a high temperature reducing gas exists. Therefore, the coal briquettes charged to the dome portion 101 by the high temperature reducing gas may be easily differentiated. However, since the coal briquettes manufactured by the method of FIG. 1 have high hot strength, the coal briquettes do not differentiate from the dome portion of the melt gasifier 10, and fall to the lower portion of the melt gasifier 10. The char generated by the pyrolysis reaction of the coal briquettes moves to the lower portion of the molten gasifier 10 and exothermicly reacts with oxygen supplied through the coal gas. As a result, the coal briquettes can be used as a heat source for keeping the molten gasifier 10 at a high temperature. On the other hand, because it provides air permeability, a large amount of gas generated in the lower portion of the melt gasifier 10 and the reduced iron supplied from the reducing furnace 20 can pass through the coal filling layer in the melt gasifier 10 more easily and uniformly. Can be.

In addition to the coal briquettes described above, a bulk coal material or coke may be charged into the melt gasifier 60 as necessary. An air vent 80 is provided on the outer wall of the melt gasifier 60 to blow in oxygen. Oxygen is blown into the coal packed bed to form a combustion zone. The coal briquettes may be burned in a combustion zone to generate reducing gas.

FIG. 3 schematically shows an apparatus for manufacturing molten iron 200 using the coal briquettes manufactured in FIG. 1. The structure of the apparatus for manufacturing molten iron 200 of FIG. 3 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the apparatus for manufacturing molten iron 200 of FIG. 3 may be modified in various forms. Since the structure of the apparatus for manufacturing molten iron 200 of FIG. 3 is similar to that of the apparatus for manufacturing molten iron 100 of FIG. 2, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted.

As shown in FIG. 3, the apparatus for manufacturing molten iron 100 includes a molten gasifier 10, a reducing furnace 22, a reduced iron compression device 40, and a compressed reduced iron storage tank 50. Here, the reduced reduced iron storage tank 50 can be omitted.

The manufactured coal briquettes are charged into a molten gasifier 10. Here, the coal briquettes generate a reducing gas in the molten gasifier 10 and the generated reducing gas is supplied to a fluidized bed reducing furnace. The iron ore is supplied to a plurality of reducing furnaces 22 having a fluidized bed, and is made of reduced iron while flowing by the reducing gas supplied from the melt gasifier 10 to the reducing furnaces 22. The reduced iron is compressed by the reduced iron compression device 40 and then stored in the reduced reduced iron storage tank (50). The compressed reduced iron is supplied from the compressed reduced iron storage tank 50 to the melt gasifier 10 and melted in the melt gasifier 10. Since the coal briquettes are supplied to the molten gasifier 10 and turned into air permeable, a large amount of gas and compressed reduced iron generated in the lower part of the molten gasifier 10 make the coal filling layer in the molten gasifier 10 easier and more uniform. It can be passed 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

Pulverized coal having an average property and having a particle size of 3.4 mm or less was prepared. Pulverized coal was prepared by mixing metallurgical coal and low grade coal. The pulverized coal was further mixed with a carbon source additive. The properties of the used metallurgical coal, low quality coal and carbon source additives are shown in Table 1 below. The volatile matter content of low-grade coal D and low-grade coal E was 30% or more, and the free swelling index was 1.

Table 1

After mixing 2.7 parts by weight of quicklime as a curing agent with respect to 100 parts by weight of pulverized coal, 10 parts by weight of molasses was uniformly mixed as a binder to prepare a mixture. The mixture was compressed with a roll press to produce pillow-shaped coal briquettes having a size of 64.5 mm × 25.4 mm × 19.1 mm. And the hot strength of the coal briquettes was measured.

Comparative example

Pulverized coal was prepared using metallurgical coal and carbon source additives without using low-grade coal for comparison with the above-described experimental example. The manufacturing process of the remaining coal briquettes was the same as the above-described experimental example.

Experimental Example 1

Pulverized coal was prepared by mixing 35 wt% metallurgical coal A, 25 wt% metallurgical coal B, 30 wt% low-grade coal E, and 10 wt% carbon source additive.

Experimental Example 2

Pulverized coal was prepared by mixing 35 wt% metallurgical coal A, 20 wt% metallurgical coal B, 30 wt% low grade E, and 15 wt% carbon source additive.

Experimental Example 3

Pulverized coal was prepared by mixing 60 wt% of metallurgical coal A, 30 wt% of low grade D, and 10 wt% of a carbon source additive.

Experimental Example 4

Pulverized coal was prepared by mixing 40 wt% metallurgical coal A, 50 wt% low-grade coal D, and 10 wt% carbon source additive.

Experimental Example 5

Pulverized coal was prepared by mixing 40 wt% metallurgical coal A, 30 wt% metallurgical coal B, and 30 wt% low grade coal D.

Experimental Example 6

Pulverized coal was prepared by mixing 20 wt% of metallurgical coal A, 70 wt% of low grade coal D, and 10 wt% of a carbon source additive.

Experimental Example 7

Pulverized coal was prepared by mixing 20 wt% of metallurgical coal C, 70 wt% of low-grade coal D, and 10 wt% of a carbon source additive.

Comparative Example 1

Pulverized coal was prepared by mixing 35 wt% metallurgical coal A, 25 wt% metallurgical coal B, 30 wt% metallurgical coal C, and 10 wt% carbon source additive.

Experiment result

Hot strength, shear strength and fixed carbon of the coal briquettes prepared according to Experimental Examples 1 to 7 and Comparative Example 1 were measured.

Hot strength measurement experiment

The hot strength of the coal briquettes was measured to determine the degree of differentiation of the coal briquettes generated in the melt gasification furnace. To this end, about 1 kg of coal briquettes at room temperature were introduced into a cylindrical reactor having a diameter of 280 mm under heating conditions set at 1000 ° C. and a nitrogen inert atmosphere, and the cylindrical reactor was rotated for 15 minutes at a rotation speed of 2 rpm. Then, by rotating the cylindrical reactor for 30 minutes at a rotation speed of 20rpm to produce a char briquette (char). The less the degree of differentiation of coal briquettes, the better the hot strength was. Therefore, the hot strength was measured by the ratio of char with a grain size of 10mm or more as an opposing ratio.

Ultimate Measurement Experiment

The strength of the coal briquettes was evaluated by using an I-type drum device for measuring the hot strength of metallurgical coke in order to determine whether the strength of the coal produced in the coal briquette hot strength measuring device was lowered. That is, 200g of coal briquettes having a particle size of 16 mm or more are put in a type I drum for measuring coke hot strength having a length of 600 mm, rotated 600 at a speed of 20 revolutions per minute, and the residual ratio of 10 mm or more is measured and the wear resistance of the coal briquettes is measured. And impact strength were measured. The larger the opposing ratio of the coal briquettes obtained by the hot strength measuring method and the higher the coal briquette strength is, the lower the coal briquette differentiation in the molten gasifier is, and the high strength of the coal briquettes can be ensured. The measurement results of the above-described hot strength and the highest strength and the amount of fixed carbon measured are shown in Table 2 below.

TABLE 2

As shown in Table 2, the hot strength, shear strength, and fixed carbon of the coal briquettes prepared according to Experimental Examples 1 to 5 were almost similar to the hot strength, shear strength, and fixed carbon of the coal briquettes prepared according to Comparative Example 1. It was. Therefore, even when fine coal was produced by mixing low-grade coal, coal briquettes having the same characteristics as those of coal briquettes containing no low-grade coal could be produced. However, when the coal briquettes were manufactured using a large amount of low-grade coal as in Experimental Example 6 and Experimental Example 7, the highest strength was lower than that of the coal briquettes manufactured according to Experimental Examples 1 to 5, and the hot strength thereof. Since it also fell, it was not suitable for use as coal briquettes. Therefore, when a certain amount of low-grade coal was blended, it was confirmed that the characteristics of the coal briquettes were kept as they were while lowering the production cost of coal briquettes.

Although the present invention has been described above, it will be readily understood by those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the claims set out below.

[Description of the code]

10. Melt Gasification Furnace

20, 22. Reduction Furnace

30. Flute

40. Reduced iron compression device

50. Compressed Reduced Iron Storage Tank

100, 200. molten iron manufacturing equipment

101. Dome

Claims (8)

A molten gas furnace in which reduced iron is charged, and A reducing furnace connected to the melt gasifier and providing the reduced iron In the molten iron manufacturing apparatus comprising a method for manufacturing coal briquettes which is charged into the dome portion of the molten gasifier rapidly heated; Providing pulverized coal, Preparing a mixture by mixing 1 to 5 parts by weight of a curing agent and 5 to 15 parts by weight of a binder with respect to 100 parts by weight of the pulverized coal, and Shaping the mixture Including, In the step of providing the pulverized coal, the pulverized coal includes a lower quality coal which is greater than 0 and 50 wt% or less, and the remaining carbon material, and the low quality coal has a volatile matter (anhydrous basis, dry basis) of 25 wt% to 40 wt%. A method for producing coal briquettes having a large and less than 3 crucible expansion index. The method of claim 1, In the step of providing the pulverized coal, the anhydrous reference high calorific value (gross calorific value) of the low-grade coal is 5,500 Kcal / kg to 7,000 Kcal / kg manufacturing method of coal briquettes. The method of claim 1, In the step of providing the pulverized coal, a method for producing coal briquettes is added to the pulverized coal is greater than 0 and less than 20wt% carbon source additive. The method of claim 3, The carbon source additive includes at least one carbon source selected from the group consisting of powdered coke, coke dust, graphite, activated carbon, and carbon black, and the amount of the first carbon included in the carbon source additive is greater than the amount of the second carbon included in the carbonaceous material. How to make a lot of coal briquettes. The method of claim 1, In the step of providing the pulverized coal, the amount of low-grade coal is a manufacturing method of coal briquettes 10wt% to 40wt%. The method of claim 5, The amount of low-grade coal is a method of producing coal briquettes of 15wt% to 30wt%. The method of claim 1, In the step of preparing the mixture, the hardening agent is coal briquette which is at least one material selected from the group consisting of quicklime, slaked lime, limestone, calcium carbonate, cement, bentonite, clay, silica, silicate, dolomite, phosphoric acid, sulfuric acid and oxide Method of preparation. The method of claim 1, In the step of preparing the mixture, the binder is molten, bitumen, asphalt, coal tar, pitch, starch, water glass, plastics, polymer resin and a method for producing coal briquettes selected from the group consisting of oil.

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