Coal briquette manufacturing method and coal briquettes manufactured using the same
Technology field
[1]
The present invention relates to a method for manufacturing coal briquettes and coal briquettes manufactured using the same, and more particularly, to a method for manufacturing coal briquettes capable of preventing clogging of a molten gas furnace pipe during manufacturing of molten iron and coal briquettes manufactured using the same.
Background
[2]
In the steel mills around the world, a molten-reduction iron-making method has been developed to directly use ordinary coal as a fuel and a reducing agent, and to manufacture molten iron by directly using iron ore, which occupies more than 80% of the world's ore production, as an iron source.
[3]
In the molten-reduction iron-making method, iron ore is reduced and charged coal is charged into a molten gasification furnace, oxygen-containing gas is injected into the molten gasification furnace to burn coal briquettes, and molten iron is melted using heat generated as the coal briquettes are burned. Prepare molten iron.
[4]
On the other hand, coal briquettes can be produced by mixing the pulverized coal and a binder, and pressure-molding a mixture of the pulverized coal and the binder in a molding machine. Coal briquettes are used as fuel materials in the manufacturing of molten iron, and it is necessary to have cold strength and hot strength in order to stably charge the inside of the molten gasifier. Accordingly, molasses and the like having excellent viscosity are used as a binder.
[5]
However, because molasses has different components depending on the production area, and it is difficult to control the components according to the sugar production process, when using molasses as a binder to manufacture coal briquettes, the quality of the coal briquettes cannot be constantly controlled.
[6]
In addition, because molasses contains a large amount of alkali components, when a coal briquette manufactured using molasses is used in a melt gasifier, a large amount of low-melting compounds such as KCl are generated. The low-melting-point compound thus generated is contained in a reducing gas to block the piping through which the reducing gas is discharged, and is attached to a fluidized bed reduction furnace to produce reduced iron using the reducing gas. plate), there is a problem of lowering the process efficiency.
[7]
(Prior Art Document 1) KR0627469 B
[8]
(Prior Art Document 2) KR10-2017-0018275 A
Detailed description of the invention
Technical challenges
[9]
The present invention provides a method for manufacturing coal briquettes capable of suppressing the production of a low-melting point compound and coal briquettes manufactured using the same.
[10]
The present invention provides a method for manufacturing coal briquettes capable of improving operation efficiency and productivity by suppressing equipment damage and coal briquettes manufactured using the same.
Task resolution
[11]
A method for manufacturing coal briquettes according to an embodiment of the present invention includes a process of preparing a raw material including pulverized coal and dextrin; Preparing a mixture by mixing the raw materials; Aging the mixture; It may include; the process of molding the aged mixture to produce coal briquettes.
[12]
In the process of preparing the raw material, a process of preparing dextrin having a DE (Dextrose Equivalent) of greater than 0 and less than or equal to 10 may be included.
[13]
In the process of preparing the raw material, a process of preparing a dextrin having a particle size of 10 to 20 μm may be included.
[14]
The process for preparing the mixture may include mixing 91 to 97 wt% of the pulverized coal and 3 to 9 wt% of the dextrin with respect to 100 wt% of the total weight of the pulverized coal and the dextrin.
[15]
The aging process may include heating the mixture using steam to maintain 50 to 100 ° C.
[16]
In the aging process, the mixture may include adjusting the mixture to have a water content of 3 to 10 wt% with respect to 100 wt% of the total mixture.
[17]
In the aging process, a process of adjusting the ratio of the amount of water to the amount of dextrin to 1 to 3 may be included.
[18]
The aging process may include a process of stirring the mixture.
[19]
The aging process can be performed for 7 to 20 minutes.
[20]
The coal briquettes according to the embodiment of the present invention include pulverized coal and dextrin, and the dextrin may exist in a gelatinized state.
Effects of the Invention
[21]
According to the embodiments of the present invention, it is possible to manufacture coal briquettes having excellent strength using a binder of dextrin that does not contain the alkali component calcium (K). Therefore, the strength of the coal briquettes can be secured, and when the molten iron is manufactured using the coal briquettes, the production of a low melting point compound by the alkali component can be suppressed or prevented. Through this, it is possible to suppress clogging of pipes due to a low melting point compound or generation of deposits in the facility. For example, clogging of the piping in the molten gasification furnace can be suppressed, and clogging such as a dispersion plate in a flow reduction furnace can be suppressed. In addition, since the equipment can be stably operated, maintenance of the equipment can be facilitated, and operation efficiency and productivity can be improved.
Brief description of the drawing
[22]
1 is a view schematically showing the configuration of a molten iron manufacturing apparatus according to an embodiment of the present invention.
[23]
2 is a view schematically showing the configuration of a coal briquette manufacturing apparatus according to an embodiment of the present invention.
[24]
3 is a flowchart sequentially showing a method for manufacturing coal briquettes according to an embodiment of the present invention.
Mode for carrying out the invention
[25]
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those skilled in the art is completely It is provided to inform you. In order to clearly express various elements in the drawings, the size is exaggerated or enlarged, and the same reference numerals in the drawings refer to the same elements.
[26]
[27]
Before explaining the present invention, the configuration of the molten iron manufacturing apparatus will be described.
[28]
1 is a view schematically showing the configuration of a molten iron manufacturing apparatus according to an embodiment of the present invention, Figure 2 is a view schematically showing the configuration of a coal briquette manufacturing apparatus according to an embodiment of the present invention. In Fig. 1, the solid line represents the movement path of the raw material, and the dotted line represents the movement path of the gas.
[29]
Referring to FIG. 1, the molten iron manufacturing apparatus includes a flow reduction furnace 200 for reducing iron ore to produce reduced iron, a coal briquette supply device 300, and a molten gasifier 100 for manufacturing molten iron using reduced iron and coal briquettes. It may include. In addition, the molten iron manufacturing apparatus may include a molding apparatus 400 for molding the reduced iron into a mass of light in a hot state.
[30]
The flow reduction furnace 200 is a means for reducing iron ore to produce reduced iron, and the iron ore may be iron ore, and may input auxiliary materials as necessary. That is, in the flow reduction furnace 200, a space for reducing iron ore may be formed therein, and a dispersion plate capable of uniformly diffusing the gas supplied into the flow reduction furnace 200, for example, reduction gas, may be formed therein. Can be installed. Accordingly, the flow reduction furnace 200 may be reduced while flowing iron ore by a reducing gas therein. A plurality of such flow reduction furnaces 200 may be provided, and iron ore may be made of reduced iron while sequentially moving the plurality of flow reduction furnaces 200. For example, the flow reduction furnace may include three flow reduction furnaces (hereinafter, a first flow reduction furnace 201, a second flow reduction furnace 202, and a third flow reduction furnace 203). At this time, the first flow reduction furnace 201 is a place where iron ore is initially charged, and the iron ore may be dried and preheated using exhaust gas and reduction gas discharged from the second flow reduction furnace 202. The iron ore dried and preheated in the first flow reduction furnace 201 is reduced or preliminarily reduced while passing through the second flow reduction furnace 202, and the second flow reduction furnace 202 is in the third flow reduction furnace 203. Iron ore can be reduced with exhaust gas and reducing gas. In addition, the third flow reduction furnace 203 may finally reduce the iron ore by the reducing gas discharged from the molten gasification furnace 100. The number of flow reduction furnaces 200 is not limited to this, and can be adjusted as necessary.
[31]
The molding apparatus 400 may compact the reduced iron produced in the flow reduction furnace 200, that is, the reduced iron in a fine state in a hot state. The molding apparatus 400 is a first reservoir 410 for storing the reduced iron discharged from the flow reduction furnace 200, and receiving the reduced iron from the first reservoir 410 to produce compacted reduced iron such as briquettes, etc. The first molding machine 420 may include a second storage machine (not shown) that temporarily stores the molded body manufactured by the first molding machine 420 and supplies it to the molten gasifier 100. At this time, the first molding machine 420 may be a twin-roll type molding machine having a pair of rolls installed to face each other. Accordingly, when the reduced iron in the powder state is charged between the pair of rolls, the reduced iron compacted by extrusion due to rotation of the pair of rolls can be manufactured.
[32]
The coal briquette manufacturing apparatus 300 may produce a coal briquette by pressure-molding a mixture of pulverized coal and a binder, and charge the produced coal briquettes into the melt gasifier 100. The coal briquette manufacturing apparatus 300 is a mixer 310 for mixing the pulverized coal and the binder, a aging machine 320 for aging the mixture of the pulverized coal and the binder mixed in the mixer 310, and press-molding the aged mixture It may include a second forming machine 330 for manufacturing coal briquettes and a third reservoir 340 for storing coal briquettes and charging the coal briquettes into the molten gasifier 100. Here, the mixer 310 may be a drum mixer in which a space for accommodating pulverized coal and a binder is formed and rotatable. In addition, the aging machine 320 is provided with a body 322 in which a space for accommodating a mixture of pulverized coal and a binder is formed, a stirrer 324 capable of stirring the mixture, and steam inside the body 322. Steam supply means 326 may be included.
[33]
The configuration and structure of the coal briquette supply device 300 is not limited thereto, and may be modified in various forms.
[34]
The molten gasifier 100 may manufacture molten iron by dissolving the reduced iron compacted in the molding apparatus, and an internal space in which a reducing gas to be supplied to the flow reducing furnace 200 may be produced may be formed. The molten gasifier 100 is a reducing space for receiving reduced iron and coal ashes such as coal briquettes and coals in the lower part, and a lower space in which molten iron is manufactured, and reducing gas for supplying flue gas generated in the process of manufacturing molten iron to the flow reducing furnace 200 It may include an upper space for gas production. At this time, the upper space may be formed in a dome shape wider than the lower space, and reduced iron and charcoal (molded coal) may be charged through the upper space. The molten gasifier 100 may be provided with a tuyere (not shown) for blowing oxygen-containing gas. The oxygen-containing gas can secure a heat source for burning the carbonaceous material and melting the reduced iron.
[35]
In addition, the melt gasifier 100 may be provided with a blowing nozzle (not shown) for supplying an oxygen-containing gas to remove volatile substances such as tar generated in the process of dissolving reduced iron. Volatile materials, such as tar, are generated in the process of heating up when the carbonaceous material such as molded water and coal is charged inside the molten gasifier 100. The problem arises. Accordingly, oxygen-containing gas may be blown into the upper space of the molten gasifier 100 into which volatile substances are introduced to burn carbon monoxide or carbon dust. At this time, the temperature of the upper space is raised to about 900 to 1100 ° C using the heat of combustion generated to convert the volatile material into high temperature chemical cracking , converting it into carbon monoxide (CO) and hydrogen gas (H 2 ), and then melt gasifier 100 Can be discharged from.
[36]
[37]
Hereinafter, a method of manufacturing coal briquettes according to an embodiment of the present invention will be described.
[38]
3 is a flowchart sequentially showing a method for manufacturing coal briquettes according to an embodiment of the present invention.
[39]
Referring to FIG. 3, the method for manufacturing coal briquettes according to an embodiment of the present invention includes a process of preparing a raw material including pulverized coal and a binder (S100), a process of mixing the raw materials to prepare a mixture (S110), and a mixture. It may include a process of aging (S120) and a process of manufacturing coal briquettes using the aged mixture (S130). At this time, the binder may include dextrin. In addition, the method for manufacturing coal briquettes according to an embodiment of the present invention may further include additional processes in addition to the processes presented as necessary.
[40]
In the process of preparing the raw material, pulverized coal may use raw materials containing carbon, such as bituminous coal, subbituminous coal, anthracite, and coke. The pulverized coal preferably has a uniform particle size distribution of pulverized coal in order to reduce variations in the quality of coal briquettes. It can have an average particle size of the degree. Accordingly, the pulverized coal can be used by crushing the raw coal so as to have a particle size within a specified range. The pulverized coal may contain about 3 to 10 wt% of water based on 100 wt% of the pulverized coal. At this time, in order to control the moisture content in the pulverized coal, the process of preparing the pulverized coal may further include drying the raw coal or pulverized coal.
[41]
And the binder may include dextrin. Dextrin is produced by hydrolyzing starch with acid, heat, enzymes, etc., and can be prepared by hydrolyzing various starches such as corn, wheat, tapioca, potatoes, and rice. Dextrins can be prepared in a wide range from slightly degraded starch to low molecular weight iodine-starch reactions. Depending on the degree of hydrolysis of starch, three types of dextrins are produced: white, pale yellow, and yellow, white is high molecular weight dextrin, and yellow is low molecular weight dextrin.
[42]
The dextrin's DE (dextose equivalent) may be on the order of 0 to 10, and preferably on the order of 0 to 5. The DE of dextrin represents a measure of how much glucose is produced by decomposition of starch composed of glucose. The higher the DE, the more decomposition, and when completely decomposed to glucose, the DE is denoted as 100. If the DE of the dextrin exceeds 10, the decomposition of the starch becomes too large, and the binding strength to the pulverized coal is lowered, which may cause a problem that the coal briquette strength is lowered. Therefore, it is possible to secure the strength of the coal briquettes by using dextrin having a DE in the suggested range.
[43]
Dextrin does not contain alkali components such as potassium (K). Accordingly, if the coal briquettes manufactured using dextrin are used as a fuel material in manufacturing molten iron, it is possible to suppress the formation of low-melting compounds such as KCl generated by alkali components in the flue gas. Accordingly, it is possible to suppress the phenomenon that the piping to the molten gasification furnace is blocked by the low-melting-point compound or the dispersion plate of the flow reduction furnace is blocked.
[44]
Dextrin may be provided in a powder state, and may have a particle size of about 10 to 20㎛. At this time, when the particle size of the dextrin is larger than the suggested range, when it is mixed with the pulverized coal, it is not uniformly distributed in the pulverized coal, so the binding force to the pulverized coal may be reduced. In addition, if the particle size of dextrin is included in the suggested range, the dextrin can be uniformly distributed in the pulverized coal to secure a sufficient contact area with the pulverized coal, and need not be smaller than the suggested range.
[45]
On the other hand, when a liquid binder is used, the flowability of the binder and the pulverized coal mixture is lowered due to the high moisture content, and adhesion occurs in the process of manufacturing coal briquettes, and the mixture is unevenly charged in the molding machine. This is because the phenomenon that the strength and shape of the coal briquettes become uneven occurs. In addition, since the coal briquettes manufactured in this way have a high moisture content, in order to secure the strength of the coal briquettes, a drying process must be additionally performed prior to charging the molten gasifier, thereby increasing the overall process time and cost, and lowering process efficiency. Because it is. In addition, the binder in the liquid state is difficult to uniformly maintain the binder component due to the layer separation, and a transport vehicle is high due to the need for a special transport vehicle such as a tank lorry during transport.
[46]
In contrast, when a powdery binder is used, the flowability of the pulverized coal and the binder mixture is improved, thereby making it possible to produce uniform coal briquettes. In addition, when a powdered binder is used in manufacturing coal briquettes, the strength of coal briquettes can be sufficiently secured without additional drying before being used for operation. In addition, the powdery binder is easy to store and transport by minimizing its volume, and there is no need to worry about freezing in the winter.
[47]
When raw materials, that is, pulverized coal and dextrin as a binder are provided, the mixture is uniformly mixed in the mixer 310 to prepare a mixture. At this time, the pulverized coal may be included in an amount of 91 to 97 wt% and dextrin in an amount of 3 to 9 wt% based on 100 wt% of the total mixture. Preferably, the pulverized coal may be included in 93 to 97 wt% and dextrin in 3 to 7 wt% based on 100 wt% of the total mixture. If the content of the binder is less than the suggested range, the strength of the coal briquettes to be manufactured cannot be sufficiently secured, and if the content of the binder is greater than the suggested range, there is a problem in that the cost of manufacturing the coal briquettes increases.
[48]
The thus prepared mixture may contain 3 to 10 wt% of moisture with respect to 100 wt% of the mixture. At this time, if the amount of water contained in the mixture is less than the suggested range, in the subsequent aging process, the inside of the ripening unit 320 may be made into supersaturated steam to additionally supply moisture to the mixture. The ratio of the amount of water to the amount of dextrin can be about 1 to 3. This is to ensure the viscosity by smoothly gelatinizing dextrins during the aging process, and when the moisture content is less than the suggested range, the dextrin gelatinization reaction does not occur smoothly to ensure sufficient strength of the coal briquettes manufactured. Can't. In addition, when the moisture content is greater than the suggested range, the moisture content of the coal briquettes is increased, and there is a problem in that a drying process must be additionally performed to secure strength. However, if the amount of water in the mixture in the process of preparing the mixture is less than the suggested range, the amount of moisture can be adjusted to the range provided by adjusting the vapor pressure inside the body 322 in the process of aging the mixture.
[49]
When the mixture is prepared, the mixture is charged into the body 322 of the aging machine 320, and the mixture is aged while supplying steam inside the body 322 through the steam supply means 326.
[50]
The aging process may be performed under the condition that the internal pressure of the body 322 is 5 to 10 bar, and the internal temperature of the body 322 is 110 ° C or higher. During the aging of the mixture, the environment inside the body 322 may be controlled so that the mixture maintains about 50 to 100 ° C, preferably about 50 to 100 ° C. If the temperature of the mixture is higher than the suggested range, it takes a lot of energy to increase the temperature of the mixture, which is undesirable in terms of process efficiency. When the temperature of the mixture is lower than the suggested range, the dextrin gelatinization reaction does not occur sufficiently and has the desired strength. It is difficult to produce coal briquettes.
[51]
In the aging process, the mixture may be stirred using the stirrer 324. When the mixture is stirred using the stirrer 324, the temperature of the mixture can be uniformly controlled as a whole. In addition, in the process of aging the mixture, dextrin undergoes a gelatinization reaction to produce viscosity, and when the mixture is stirred using the stirrer 324, friction heat is generated by contact between the mixture and the stirrer 324. The frictional heat generated in this way can be used as a heat source to cause the dextrin to react with the steam supplied into the body 322.
[52]
When the mixture is aged in this way, dextrin uniformly dispersed in the pulverized coal meets moisture, and when the temperature inside the body 322 of the maturator 320 rises, it expands to cause a gelatinization reaction that changes to a high viscosity state. do. As a result, the dextrin that has been gelatinized can express the binding force to the pulverized coal, thereby greatly improving the strength of the coal briquettes produced in a subsequent process.
[53]
The aging time of the mixture can be carried out for about 7 to 20 minutes. At this time, the aging time can be performed longer than the mixing time of the raw material, which is to ensure that the dextrin is uniformly and sufficiently gelatinized in the pulverized coal. In addition, since raw materials, that is, pulverized coal and dextrin are provided in powder form, it does not take much time to uniformly mix them, but in the aging process, it takes a lot of time to stir the mixture uniformly because dextrin is viscous and viscous. to be. Therefore, the aging time is preferably performed 2 to 5 times longer than the time for preparing a mixture of pulverized coal and dextrin.
[54]
When the aging process is completed, the mixture is withdrawn from the aging machine 320 and the body 322 to be charged to the second molding machine 330 to produce coal briquettes. Coal briquettes can be produced by loading and pressing a mixture aged between a pair of rollers, and can be formed in various forms such as a briquette or strip shape. When manufacturing coal briquettes, the molding pressure may be adjusted so that the coal briquettes produced have an apparent density of about 1.25 to 1.35 kg / m 3. Accordingly, coal briquettes having strength that can be used in a molten gasifier can be produced.
[55]
The coal briquettes manufactured in this way may be temporarily stored in the third reservoir 340 and then charged into the molten gasifier 100 for manufacturing molten iron.
[56]
[57]
Hereinafter, an experimental example for verifying the physical properties of the coal briquettes manufactured by the embodiment of the present invention and the effect obtained when the coal briquettes are applied to an actual operation will be described.
[58]
Experiment for measuring hot and cold strength of coal briquettes
[59]
The pulverized coal and dextrin powder having a particle size of less than 3.4 mm and 90% or more were uniformly mixed for 2 to 3 minutes, and then added to the aging machine, and steam was supplied to the inside of the aging machine to increase the temperature inside the aging machine, followed by aging mixing for a certain period of time. . At this time, as the pulverized coal, a mixture of strong coal, pulverized coal and pulverized coke was used, and the dextrin used WSCR Wheat Dextrin manufactured by MANILDRA. Upon aging, the mixture of pulverized coal and dextrin was stirred using a stirrer.
[60]
Then, the aged mixture was charged between a pair of rolls of a second molding machine to prepare coal briquettes. When manufacturing the coal briquettes, the rolls of the second molding machine pressurized the mixture at a pressure of 20 kN / cm to produce a pillow-shaped coal briquette having a size of 64.5 mm × 25.4 mm × 19.1 mm.
[61]
Experimental Example 1
[62]
95.5 wt% of pulverized coal having a water content of 7.6 wt% and 4.5 wt% of powdered dextrin were mixed for 3 minutes, and then added to the maturing machine for aging for 10 minutes. At this time, a dextrin having a DE of 2 was used, and the moisture content of the aged mixture discharged from the ripening machine was 7.4 wt%, and the temperature was 62 ° C. Then, the mixture was charged between a pair of rolls to produce coal briquettes. When the coal briquettes were produced, they were left at room temperature for about 1 hour, and then the drop strength and compressive load were measured. The drop strength of the coal briquettes was obtained from the proportion of coal briquettes having a particle size of 20 mm or more after 2 kg of coal briquettes prepared by each experimental example were free-falled at a height of 5 M eight times. In addition, the compression load of the coal briquettes was measured as the maximum load when compressed at a constant speed from the top of the coal briquettes while the lower part of the coal briquettes was fixed, and was measured as an average value of 20 samples of the coal briquettes.
[63]
Experimental Example 2
[64]
95.5 wt% of pulverized coal having a water content of 8.0 wt% and 4.5 wt% of powdered dextrin were mixed for 3 minutes, and then put into the maturing machine for 15 minutes of aging treatment. At this time, dextrin having a DE of 2 was used, and the moisture content of the aged mixture discharged from the ripening machine was 6.9 wt%, and the temperature was 68 ° C. Then, the mixture was charged between a pair of rolls to produce coal briquettes. When the coal briquettes were produced, the drop strength and the compressive load were measured in the same manner as in Experimental Example 1.
[65]
Experimental Example 3
[66]
95.5 wt% of pulverized coal having a water content of 6.2 wt% and 4.5 wt% of powdered dextrin were mixed for 3 minutes, and then put into the maturing machine for 10 minutes of aging treatment. At this time, dextrin having a DE of 2 was used, and the moisture content of the aged mixture discharged from the ripening machine was 5.4 wt%, and the temperature was 63 ° C. Then, the mixture was charged between a pair of rolls to produce coal briquettes. When the coal briquettes were produced, the drop strength and the compressive load were measured in the same manner as in Experimental Example 1.
[67]
Experimental Example 4
[68]
95.0 wt% of pulverized coal having a water content of 9.8 wt% and 5.0 wt% of powdered dextrin were mixed for 3 minutes, and then added to the maturing machine for aging for 10 minutes. At this time, dextrin having a DE of 2 was used, and the moisture content of the aged mixture discharged from the ripening machine was 8.5 wt%, and the temperature was 66 ° C. Then, the mixture was charged between a pair of rolls to produce coal briquettes. When the coal briquettes were produced, the drop strength and the compressive load were measured in the same manner as in Experimental Example 1.
[69]
Experimental Example 5
[70]
97.5 wt% of pulverized coal having a water content of 7.6 wt% and 2.5 wt% of powdered dextrin were mixed for 3 minutes, and then put into the maturing machine, followed by aging treatment for 10 minutes. At this time, dextrin having a DE of 2 was used, and the moisture content of the aged mixture discharged from the ripening machine was 7.2 wt% and the temperature was 63 ° C. Then, the mixture was charged between a pair of rolls to produce coal briquettes. When the coal briquettes were produced, the drop strength and the compressive load were measured in the same manner as in Experimental Example 1.
[71]
Experimental Example 6
[72]
95.5 wt% of pulverized coal having a water content of 6.0 wt% and 4.5 wt% of powdered dextrin were mixed for 3 minutes, and then added to a maturing machine for 5 minutes of aging treatment. At this time, dextrin having a DE of 2 was used, and the moisture content of the aged mixture discharged from the ripening machine was 5.8 wt%, and the temperature was 63 ° C. Then, the mixture was charged between a pair of rolls to produce coal briquettes. When the coal briquettes were manufactured, the drop strength and the compressive load were measured in the same manner as in Experimental Example 1.
[73]
Experimental Example 7
[74]
95.5 wt% of pulverized coal having a water content of 7.5 wt% and 4.5 wt% of powdered dextrin were mixed for 3 minutes, and the process of aging in a maturing machine was omitted. At this time, dextrin with a DE of 2 was used. Then, the aged mixture was charged between a pair of rolls to prepare coal briquettes. When the coal briquettes were manufactured, the drop strength and the compressive load were measured in the same manner as in Experimental Example 1.
[75]
Experimental Example 8
[76]
95.5 wt% of pulverized coal having a water content of 7.5 wt% and 4.5 wt% of powdered dextrin were mixed for 3 minutes, and then added to the maturing machine for treatment for 10 minutes. Dextrin having a DE of 42 was used, and the moisture content of the aged mixture discharged from the ripening machine was 7.1 wt% and the temperature was 62 ° C. Then, the mixture was charged between a pair of rolls to produce coal briquettes. When the coal briquettes were manufactured, the drop strength and the compressive load were measured in the same manner as in Experimental Example 1.
[77]
[78]
The results of Experimental Examples 1 to 8 are shown in Table 1 below.
[79]
[Table 1]
Experimental Example Mixing ratio (wt%) Aged mixture Coal quality
Pulverized coal dextrin Aging time (minutes) Moisture (wt%) Temperature (℃) Drop strength (%) Compressive load (㎏f)
Experimental Example 1 95.5 4.5 10 7.4 62 90 62
Experimental Example 2 95.5 4.5 15 6.9 68 88 78
Experimental Example 3 95.5 4.5 10 5.4 63 78 69
Experimental Example 4 95.0 5.0 10 8.5 66 97 74
Experimental Example 5 97.5 2.5 10 7.2 63 49 37
Experimental Example 6 95.5 4.5 5 5.8 63 62 49
Experimental Example 7 95.5 4.5 0 7.5 25 24 14
Experimental Example 8 95.5 4.5 10 7.1 62 57 44
[80]
Referring to Table 1, it can be seen that in the case of Experimental Examples 1 to 4 manufactured by the method for manufacturing coal briquettes according to the present invention, the drop stress and compression load of the coal briquettes were measured very well. That is, in the case of coal briquettes manufactured under the conditions suggested by the method for manufacturing coal briquettes of the present invention, the drop strength was 70% or more and the compressive load was 60 kgf or more.
[81]
However, in the case of Experimental Example 5 in which the content of dextrin was less than the range suggested in the present invention, the drop strength and compressive load of the briquettes were measured lower than those in Experimental Examples 1 to 4.
[82]
In addition, in the case of Experimental Example 6 in which aging was performed shorter than the range suggested in the present invention and Experimental Example 7 without aging, the drop strength and compressive load of the coal briquettes were measured lower than those in Experimental Examples 1 to 4.
[83]
In addition, although the content and aging time of the raw materials are included in the ranges presented in the present invention, in the case of Experimental Example 8 using dextrin having DE of 42, the drop strength and compressive load of coal briquettes were compared to Experimental Examples 1 to 4. Measured low.
[84]
Through this, it was found that the strength of the coal briquettes can be sufficiently secured when the content and process conditions of the raw materials suggested in the present invention are satisfied when manufacturing the coal briquettes.
[85]
[86]
When using the coal briquettes produced by the present invention in actual operation, an experiment for determining the degree of formation of low melting point compounds and the like will be described.
[87]
Experimental Example 9
[88]
The coal briquettes prepared by Experimental Example 4 were crushed to obtain a fine powder. Then, about 7 g of crushed coal briquettes, such as Sample 1, was charged into a 30 ml magnetic crucible. Then, the magnetic crucible was charged to a furnace at 850 ° C., and then heated for 10 hours to combust Sample 1. Subsequently, the components of the burned sample 1 were analyzed.
[89]
Experimental Example 10
[90]
2.7 parts by weight of quicklime and 11 parts by weight of molasses were uniformly mixed with 100 parts by weight of pulverized coal having a particle size of 3.4 mm or less and 90% or more. Then, the mixture was charged between a pair of rolls to prepare coal briquettes. At this time, when manufacturing coal briquettes, coal briquettes of the same size were manufactured using the same molding pressure as Experimental Example 4. The coal briquettes thus produced were crushed to obtain a fine powder. Then, about 7 g of crushed coal briquettes, for example, Sample 2, was charged into a 30 ml magnetic crucible. Then, the magnetic crucible was charged to a furnace at 850 ° C., and then heated for 10 hours to combust Sample 2. Subsequently, the components of the burned sample 2 were analyzed.
[91]
Table 2 below shows the results of analyzing the components of Samples 1 and 2.
[92]
[Table 2]
division Briquette Ash component (wt%)
SiO2 High Al 2 O 3 MgO TiO2 Fe 2 O 3 K2O Na 2 O
Experimental Example 9 50.9 8.2 24.3 2.2 1.3 8.2 1.9 0.8
Experimental Example 10 38.8 27.3 20.2 2.2 1.0 4.6 3.3 0.3
[93]
Looking at Table 2, it can be seen that in the case of coal briquettes manufactured using dextrin, the amount of the alkali component, that is, K 2 O , which generates deposits on piping or equipment, is significantly reduced compared to coal briquettes manufactured using molasses. . Since the dextrin used as the binder does not contain the K component, it is preferable that K 2 O is not detected after burning the sample 1, but the K 2 O component is detected because the K powder is partially contained in the pulverized coal. It seems to have been done.
[94]
When the coal briquettes manufactured using dextrin as described above are used in a molten gasifier, the production of low-melting compounds such as KCl (melting point 770 ° C) generated by alkali components can be suppressed. Therefore, during the manufacturing of the molten iron, the piping of the molten gasifier is blocked, or the production of stable deposits can be suppressed by suppressing the formation of deposits by low-melting compounds in the flow reduction furnace that reduces iron ore using the reducing gas generated in the molten gasifier. .
[95]
[96]
Although the technical spirit of the present invention has been specifically described according to the above-described embodiment, it should be noted that the above-described embodiment is for the purpose of explanation and not for the limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical spirit of the present invention.
Industrial availability
[97]
The method for manufacturing coal briquettes according to an embodiment of the present invention and the coal briquettes manufactured using the same can suppress clogging of piping by low-melting point compounds or generation of deposits in the facility, thereby suppressing clogging of the piping in the facility, and the dispersion plate of the flow reduction furnace. By suppressing clogging of the back, it is possible to stably operate the equipment, thereby improving operating efficiency and productivity.
[98]
Claim
[Claim 1]
Preparing a raw material containing pulverized coal and dextrin; Preparing a mixture by mixing the raw materials; Aging the mixture; Forming the coal briquettes by molding the aged mixture; Coal briquette manufacturing method comprising a.
[Claim 2]
The method according to claim 1, In the process of preparing the raw material, DE (Dextrose Equivalent) DE is more than 0, including the process of preparing a dextrin that comprises 10 or less.
[Claim 3]
The method according to claim 2, In the process of preparing the raw material, a method of manufacturing coal briquettes comprising a process of preparing a dextrin having a particle size of 10 to 20 μm.
[Claim 4]
The method according to claim 3, The process of preparing the mixture, for the total weight of 100wt% of the sum of the pulverized coal and the dextrin, the pulverized coal is 91 to 97wt% and the dextrin is 3 to 9wt% mixed coal manufacturing process Way.
[Claim 5]
The method of claim 4, wherein the aging process comprises heating the mixture using steam to maintain the mixture at 50 to 100 ° C.
[Claim 6]
The method of claim 5, wherein in the aging process, the mixture comprises a process of adjusting the mixture to have a water content of 3 to 10 wt% with respect to 100 wt% of the total mixture.
[Claim 7]
The method according to claim 6, In the aging process, the seonghyeongtan manufacturing method comprising the step of adjusting the ratio of the amount of water to the amount of dextrin to 1 to 3.
[Claim 8]
The method of claim 7, wherein the aging process includes a step of stirring the mixture.
[Claim 9]
The method of claim 8, wherein the aging process is performed for 7 to 20 minutes.
[Claim 10]
Coal briquettes comprising pulverized coal and dextrin, the dextrin being in a luxurious state.