KR100930680B1 - Molten iron manufacturing equipment and molten iron manufacturing method - Google Patents

Abstract

The present invention relates to a molten iron manufacturing apparatus and a molten iron manufacturing method. The molten iron manufacturing apparatus includes: i) one or more reduction furnaces for reducing iron ore to produce reduced iron; Iii) an exhaust gas supply pipe for circulating the exhaust gas discharged from the reduction furnace to the reduction furnace, and iii) one or more reformers installed in the exhaust gas supply pipe to increase the amount of hydrogen contained in the exhaust gas.

PSA, WGSR, Gas, Reform

Description

Apparatus for manufacturing molten iron and method for manufacturing molten iron {APPARATUS FOR MANUFACTURING MOLTEN IRON AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to an apparatus for manufacturing molten iron and a method for manufacturing molten iron, and more particularly, to an apparatus for manufacturing molten iron and a method for manufacturing molten iron, which improves reducing power of reducing gas.

Recently, a molten reduced iron production method which replaces the blast furnace method has been developed as a molten iron manufacturing method. In the molten iron reduction method, ordinary coal is directly used as a fuel and a reducing agent, and iron ore is directly used as an iron source to reduce iron ore in a reduction furnace and to produce molten iron in a melt gasifier.

Oxygen is blown into the melt gasifier to combust the coal packed bed in the melt gasifier. Oxygen is converted to reducing gas and discharged from the melt gasifier. The reducing gas discharged from the melt gasifier is sent to the reduction furnace. In the reduction furnace, iron ore is reduced by the reducing gas. The reducing gas which reduced iron ore is discharged | emitted from a reduction furnace as waste gas.

An object of the molten iron manufacturing apparatus for improving the reducing power of the reducing gas. In addition, an object of the present invention is to provide a method for manufacturing molten iron that improves reducing power of reducing gas.

In the molten iron manufacturing apparatus according to an embodiment of the present invention, iii) at least one reduction furnace for reducing iron ore to produce reduced iron, ii) is connected to a reduction furnace charged with iron, the bulk carbon is charged, oxygen is blown A melt gasification furnace for producing molten iron, i) comprising an exhaust gas supply pipe for circulating exhaust gas discharged from a reduction furnace to a reduction furnace, and iii) one or more reformers installed in the exhaust gas supply pipe to increase the amount of hydrogen contained in the exhaust gas.

One or more reformers may be a water gas shift reactor (WGSR) or a pressure swing absorber (PSA). One or more reformers include a plurality of reformers, and the plurality of reformers may include WGSR and PSA.

The compressor may further include a compressor installed at the exhaust gas supply pipe to compress the exhaust gas, and the compressor may be positioned alongside the WGSR at the front or the rear of the WGSR. WGSR converts carbon monoxide contained in flue gas to hydrogen, and PSA can adsorb carbon dioxide contained in flue gas. Hydrogen passing through the WGSR may be at least 38 vol% and less than 100 vol% of the exhaust gas.

PSA can extract and discharge hydrogen from flue gas. The hydrogen released from the PSA may be at least 97 vol% and less than 100 vol% of the flue gas. It may further include a steam blower connected to the reduction furnace to blow steam into the reduction furnace.

The reduction furnace may be a packed bed reduction furnace or a fluidized bed reduction furnace. When the reduction furnace is a fluidized bed reduction furnace, the one or more reduction furnaces may comprise a plurality of flow reduction reactors. The plurality of flow reduction reactors may include: a first flow reduction reactor for preheating iron ore, a second flow reduction reactor connected with the first flow reduction reactor, and preliminarily reducing preheated iron ore, and a second flow reduction reactor, and And a third flow reduction reactor for finally reducing the iron ore, and the molten iron manufacturing apparatus may further include a steam blower installed between the first flow reduction reactor and the second flow reduction reactor to blow steam into the first flow reduction reactor. have.

The molten iron manufacturing apparatus according to an embodiment of the present invention may further include a reducing gas supply pipe for supplying the reducing gas discharged from the molten gasifier to the reduction furnace. The reducing gas supply pipe may be connected to the exhaust gas supply pipe. The exhaust gas supply pipe is installed in the molten gasifier to supply the exhaust gas to the molten gasifier through a vent for blowing oxygen, and the exhaust gas may be circulated to the reduction furnace via the molten gasifier.

The method for manufacturing molten iron according to an embodiment of the present invention includes the steps of: i) charging iron ore into a reduction furnace to produce reduced iron, ii) charging the bulk carbonaceous material into a melting gasifier, and iii) charging reduced iron into a melt gasifier. (B) preparing molten iron by injecting oxygen into a molten gas furnace to melt reduced iron; and iii) at least one reformer installed in a flue gas supply pipe connected with a reduction furnace to supply exhaust gas discharged from the reduction furnace. Thereby increasing the amount of hydrogen contained in the flue-gas, and iii) feeding the reformed flue-gas to the reduction furnace.

In the step of increasing the amount of hydrogen contained in the flue-gas, one or more reformers may be WGSR or PSA. One or more reformers include a plurality of reformers, and the plurality of reformers may include WGSR and PSA.

The method may further include compressing the exhaust gas by a compressor installed in the exhaust gas supply pipe, and in the compressing the exhaust gas, the compressor may be positioned parallel to the WGSR at the front or the rear of the WGSR. After the step of compressing the exhaust gas, a step of increasing the amount of hydrogen contained in the exhaust gas may be made.

WGSR converts carbon monoxide contained in flue gas to hydrogen, and PSA can adsorb carbon dioxide contained in flue gas. Hydrogen passing through the WGSR may be at least 38 vol% and less than 100 vol% of the exhaust gas. PSA can extract and discharge hydrogen from flue gas. The hydrogen released from the PSA may be at least 97 vol% and less than 100 vol% of the flue gas. The method may further include injecting steam into the reduction furnace.

Preparing the reduced iron includes preheating the iron ore, preliminarily reducing the preheated iron ore, and finally reducing the prereduced iron ore, and steam may be used in the preheating of the iron ore. In the step of preparing iron ore by charging the iron ore into a reduction furnace, the reduction furnace may be a packed-bed reduction furnace or a fluidized-bed reduction furnace.

The molten iron manufacturing method according to an embodiment of the present invention may further comprise the step of supplying a reducing gas generated in the molten gasifier to the reduction furnace. In the step of supplying the reformed exhaust gas to the reduction furnace, the reformed exhaust gas may be mixed with the reducing gas and supplied to the reduction furnace. In the step of producing molten iron, oxygen may be supplied to the molten gasifier through the tuyere installed in the molten gasifier. In the step of supplying the reformed exhaust gas to the reduction furnace, the reformed exhaust gas may be supplied to the molten gasifier through the tuyere, and the reformed exhaust gas may be supplied to the reduction furnace via the molten gasifier.

By reducing the reducing gas by using WGSR and PSA, the reducing power of the reducing gas can be greatly improved. In addition, since the reducing gas is used to increase the hydrogen content, the melting point of the iron ore is significantly lowered, it is possible to significantly reduce the fuel cost when manufacturing molten iron.

With reference to the accompanying drawings, it will be described embodiments of the present invention to be easily implemented by those skilled in the art. As can be easily understood by those skilled in the art, the embodiments described below may be modified in various forms without departing from the concept and scope of the present invention. Where possible the same or similar parts are represented with the same reference numerals in the drawings.

All terms including technical terms and scientific terms used below have the same meaning as those commonly understood by those skilled in the art. Terms defined in advance 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.

1 schematically shows a molten iron manufacturing apparatus 100 according to a first embodiment of the present invention.

As illustrated in FIG. 1, the apparatus for manufacturing molten iron 100 includes a plurality of fluidized-bed reduction reactors 20, a melt gasifier 10, a reducing gas supply pipe 40, and reformers 70 and 80. In addition, the molten iron manufacturing apparatus 100 further includes a compacted material manufacturing apparatus 30, a high temperature uniform back pressure device 12 and a compacted material storage tank 16 as needed.

The molten iron manufacturing apparatus 100 manufactures molten iron by directly using iron ore and coal collected from a mountain region. First, iron ore is supplied to the fluidized-bed reduction furnace 20 to flow iron ore in the fluidized-bed reduction furnace 20. Iron ore can be used as iron ore, if necessary, can be used by mixing the side materials. A fluidized bed is formed inside the fluidized bed reduction furnace 20 to reduce iron ore. The fluidized-bed reduction reactor 20 includes a first flow reduction path 24, a second flow reduction path 25, a third flow reduction path 26, and a fourth flow reduction path 27. Although four flow reduction reactors are shown in FIG. 1, one or more flow reduction reactors may be used. In addition, although the flow reduction path is shown in FIG. 1, this is for illustrating the present invention and the present invention is not limited thereto. Therefore, other kinds of reduction furnaces may be used.

The first flow reduction path 24 preheats the iron ore with reducing gas discharged from the second flow reduction path 25. The second flow reduction path 25 and the third flow reduction path 26 preliminarily reduce the preheated iron ore. In addition, the fourth flow reduction path 27 converts the preliminarily reduced iron ore into reduced iron.

Iron ore is reduced and heated while passing through the fluidized-bed reduction furnace 20. The reducing gas generated and discharged from the melt gasifier 10 is supplied to the fluidized bed reduction furnace 20 through a reducing gas supply pipe 40. The cyclone 14 is installed to prevent the fine powder contained in the reducing gas discharged from the melt gasifier 10 from scattering. Therefore, the fine powder is collected by the cyclone 14 and flows back into the melt gasifier 10. Iron ore is reduced by a reducing gas in the fluidized bed reduction furnace 20 is made of reduced iron. Reduced iron is manufactured into compacted material by the compacted material manufacturing apparatus 30.

The compacted material manufacturing apparatus 30 includes the charging hopper 31, the pair of rolls 33, the crusher 35, and the storage tank 37. In addition, the compacted material manufacturing apparatus 30 may further include another apparatus as needed. The charging hopper 31 stores reduced iron. The reduced iron is press-molded in strip form while charging from the charging hopper 31 to the pair of rolls 33. The press-formed reduced iron is crushed in the crusher 35 and stored in the storage tank 37.

The reduced iron stored in the storage tank 37 is transferred to the molten gasifier (10). The high temperature uniform pressure-reducing apparatus 12 adjusts the pressure between the compacted body manufacturing apparatus 30 and the melt gasifier 10, and presses the compacted body to the melt gasifier 10. The compacted material storage tank 16 temporarily stores the compacted material and charges the compacted material into the melt gasifier 10.

The bulk carbonaceous material is charged into the molten gasifier 10 to form a coal filling layer therein. The bulk coal material includes lump coal or coal briquettes. Coal briquettes are produced by press-molding pulverized coal. In addition, coke may be charged as needed. Oxygen (O ₂ ) is blown into the molten gasifier 10. Oxygen (O ₂ ) is blown into the coal packed bed to form a combustion zone, and the bulk coal ash is burned in the combustion zone to generate reducing gas. The compacted material is melted by the combustion of the bulk carbon material, and molten iron is produced and then discharged to the outside.

The fine gas is discharged from the first flow reduction path 24 via the exhaust gas pipe 50. Therefore, as shown in FIG. 1, the fine dust is collected by water using a collector oscillator 51 installed in the exhaust gas pipe 50, and only the exhaust gas is discharged through the exhaust gas pipe 50. Dust collected by water is discharged to the outside as sludge.

Some of the exhaust gas is discharged to the outside, and the remainder is passed through the tar removal device 53, the tar contained in the exhaust gas is removed. Therefore, it is possible to prevent malfunction due to condensation of tar in the reformers 70 and 80 and the gas compressor 55 located at the rear end of the tar removing device 53.

The reformers 70 and 80 extract the specific gas by reforming the exhaust gas. The reformers 70 and 80 may use a pressure swing absorber (PSA) or a water gas shift reactor (WGSR). 1 illustrates the use of WGSR 70 and PSA 80 as reformers.

The PSA includes a plurality of adsorbents in which a plurality of micropores are formed in an elongated tube. The adsorbent acts as a filter. As the adsorbent, for example, carbon molecular sieve (CMS) or zeloite molecular sieve (ZMS) may be used. As the exhaust gas passes through the adsorbent, the degree of adsorption varies according to the gas components included in the exhaust gas according to the size of the micropores. That is, some gases are adsorbed by the adsorbent, while others are not adsorbed and pass through the PSA. After the exhaust gas has passed completely through the PSA, it releases the specific gas adsorbed on the adsorbent by lowering the pressure of the PSA. The size of the fine pores that can be adsorbed according to the type of gas can be easily understood by those skilled in the art, and a detailed description thereof will be omitted.

WGSR produces certain gases from flue gases. If the WGSR is installed at the front of the PSA, the function can be properly performed. In other words, after the specific gas is generated by the WGSR and the specific gas is extracted by the PSA, not only the extraction amount of the specific gas is increased but also the purity thereof is increased.

In one example, the WGSR replaces carbon monoxide with hydrogen by adding moisture to the carbon monoxide contained in the exhaust gas using a catalyst. This reaction is carried out at a temperature of 200 ℃ to 450 ℃, it is made as shown in formula (1).

CO + H ₂ O → CO ₂ + H ₂

Hydrogen and carbon dioxide may be generated by reacting moisture with carbon monoxide in WGSR based on Formula 1 described above. Since the structure and operation principle of the above-described WGSR can be easily understood by those skilled in the art, detailed description thereof will be omitted.

As shown in FIG. 1, the tar removal device 50, the WGSR 70, the gas compressor 55, and the PSA 80 are installed in the exhaust gas supply pipe 57 branched from the exhaust gas pipe 50. The WGSR 70 is located in front of the PSA 80, and a gas compressor 55 is located between the WGSR 70 and the PSA 80. The gas compressor 55 boosts the exhaust gas. The boosted gas is provided to the PSA 80 located at the rear end of the gas compressor 55. In order to operate the PSA 80 smoothly, the gas is boosted and supplied to the gas compressor 55.

The WGSR 70 generates carbon dioxide and hydrogen by adding moisture to the exhaust gas. The WGSR 70 is located at the rear end of the tar removing device 53 to receive the exhaust gas from which tar is removed.

PSA 80 removes carbon dioxide. That is, carbon dioxide contained in the exhaust gas passing through the PSA 80 is adsorbed and removed by the adsorbent of the PSA 80, and the remaining gas passes through the PSA 80. The carbon dioxide removed from the PSA 80 may be supplied to a power plant or an ironworks. Carbon dioxide is used for fire extinguishing in power plants or steel mills.

As the exhaust gas passes through the WGSR 70 and the PSA 80, the composition ratio of the gas changes. The exhaust gas before passing through the WGSR 70 and the PSA 80 includes carbon monoxide, carbon dioxide, hydrogen, nitrogen, and the like. As the exhaust gas passes through the WGSR 70, a large amount of carbon monoxide reacts with moisture to be converted into carbon dioxide and hydrogen. And while the exhaust gas with increased carbon dioxide and hydrogen content passes through the PSA 80, carbon dioxide is removed. Therefore, the hydrogen content of the flue gas increases.

The exhaust gas passing through the PSA 80 is circulated to the fluidized bed reduction reactor 20 through the exhaust gas supply pipe 57. Here, the reformed exhaust gas is mixed with the reducing gas generated in the melt gasifier 10 and supplied to the fluidized bed reduction furnace 20. Here, the exhaust gas supply pipe 57 is connected to the pipe connecting the melt gasifier 10 and the cyclone 14 to each other. Therefore, the reformed exhaust gas is discharged from the cyclone 14 and supplied to the fluidized bed reduction furnace 20 through the reducing gas supply pipe 40. On the other hand, the cyclone 14 collects the fine powder and returns the dust collection to the molten gasifier 10 through the pipe 18. Therefore, the hydrogen contained in the exhaust gas is supplied to the fluidized bed reduction furnace 20 through the reducing gas supply pipe 40. Hereinafter, as in the first embodiment of the present invention, the effect of the hydrogen content in the reducing gas on the reduction rate of iron ore will be described.

Figure 2 shows the reduction rate of iron ore according to the hydrogen content of the reducing gas in the fluidized bed reduction reactor. In FIG. 2, line A represents a case where the hydrogen content of the reducing gas is 100 vol%, and line B represents a case where the hydrogen content of the reducing gas is 50 vol% and the carbon monoxide content is 50 vol%. And the line C represents a case where the carbon monoxide content of the reducing gas is 100 vol%. In addition, the reduction rates of iron ores at 700 ° C., 800 ° C. and 900 ° C. are indicated by rhombuses, squares, and triangles at lines A, B, and C, respectively. Here, the temperature means the temperature inside the fluidized-bed reduction furnace.

Referring to line A, when the temperatures in the fluidized bed reduction furnace are 700 ° C., 800 ° C., and 900 ° C., respectively, the reduction rates of iron ore are 75%, 88%, and 90%, respectively. In addition, referring to line B, when the temperatures in the fluidized bed reduction furnace are 700 ° C., 800 ° C., and 900 ° C., respectively, the reduction rates of iron ore are 61%, 79%, and 80%, respectively. And referring to line C, when the temperatures in the melt gasifier are 700 ° C., 800 ° C., and 900 ° C., respectively, the reduction rates of iron ore are 35%, 43%, and 52%, respectively.

Referring to FIG. 2, the reduction rate of iron ore increases as the temperature in the fluidized bed reduction furnace increases. However, when the temperature in the fluidized-bed reduction furnace is increased, iron ore sticks inside the fluidized-bed reduction furnace and does not flow well. Therefore, the temperature inside the fluidized bed reduction furnace should be maintained properly.

As shown in FIG. 2, as the content of hydrogen in the reducing gas increases, the reduction rate of iron ore increases. In line C, when using a reducing gas having a carbon monoxide content of 100 vol%, the iron ore reduction rate is 52% when the temperature in the fluidized bed reduction furnace is 900 ° C. On the other hand, in the case of using a reducing gas having a hydrogen content of 100 vol% in line A, the iron ore has a reduction rate of 75% when the temperature in the fluidized bed reduction furnace is 700 ° C. That is, by increasing the content of hydrogen in the reducing gas, it is possible to increase the iron ore reduction rate while lowering the temperature in the fluidized bed reduction furnace.

Therefore, in the first embodiment of the present invention, the exhaust gas is reformed to increase the hydrogen content, and the exhaust gas is reused as the reducing gas. Therefore, it is possible to reduce the cost of manufacturing molten iron while maximizing the energy efficiency of the molten iron manufacturing apparatus.

3 schematically shows a molten iron manufacturing apparatus 200 according to a second embodiment of the present invention. Since the apparatus for manufacturing molten iron 200 shown in FIG. 3 is similar to the apparatus for manufacturing molten iron 100 of FIG. 1, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted.

As shown in FIG. 3, the gas compressor 55 is located at the front end of the WGSR 70. The gas compressor 55 boosts the exhaust gas, and the WGSR 70 generates hydrogen from the exhaust gas. When the compressed flue gas is supplied to the WGSR 70, the reaction rate of carbon monoxide and water is increased. That is, the WGSR 70 produces hydrogen and carbon dioxide more efficiently using the boosted exhaust gas. The PSA 80 removes carbon dioxide and supplies a flue gas having a higher hydrogen content to the melt gasifier 10.

4 schematically shows a molten iron manufacturing apparatus 300 according to a third embodiment of the present invention. Since the apparatus for manufacturing molten iron 300 of FIG. 4 is similar to the apparatus for manufacturing molten iron 100 of FIG. 1, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted.

As shown in FIG. 4, the steam blower 90 is located between the first flow reduction path 24 and the second flow reduction path 25. Although the steam blower 90 is shown in FIG. 4 as being located between the first flow reduction path 24 and the second flow reduction path 25, this is merely to illustrate the present invention, the present invention is It is not limited. Therefore, the steam blower 90 can be arrange | positioned also in another position. The steam blower 90 blows steam into the fluidized-bed reduction reactor 20. The steam blower 90 is disposed between the first flow reduction path 24 and the second flow reduction path 25 to determine the amount of reducing gas for preheating the iron ore charged into the first flow reduction path 24. Increase Therefore, the preheating efficiency of iron ore can be improved.

Some of the iron ore is present in the form of iron oxide (Fe ₃ O ₄ ) during the reduction process. Therefore, when steam is blown into the steam blower 90, iron oxide acts as a catalyst and the carbon monoxide in the reducing gas reacts. Therefore, the ratio of hydrogen and carbon dioxide in the reducing gas is increased by the reaction of Chemical Formula 1 described above. This is identical to the principle of using iron oxide (Fe ₃ O ₄ ) as a catalyst in the WGSR 70 of FIG. WGSR uses hydrogen oxide (Fe ₃ O ₄ ) catalysts to produce hydrogen and carbon dioxide.

As shown in FIG. 4, some of the hydrogen increased by the steam blower 90 preheats or pre-reduces iron ore in the first flow reduction path 24, and the remaining hydrogen is exhausted through the exhaust gas pipe 50. In addition, the hydrogen content in the flue-gas is increased. In addition to hydrogen in the exhaust gas, the carbon dioxide content is high, but the carbon dioxide is removed while passing through the PSA (80). That is, in the fourth embodiment of the present invention, since the hydrogen content in the exhaust gas is increased without using WGSR, the fuel cost of the apparatus for manufacturing molten iron 300 can be greatly reduced.

5 schematically shows a molten iron manufacturing apparatus 400 according to a fourth embodiment of the present invention. Since the apparatus for manufacturing molten iron 400 of FIG. 5 is similar to the apparatus for manufacturing molten iron 100 of FIG. 1, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted.

As the exhaust gas passes through the WGSR 70, the content of carbon dioxide and hydrogen in the exhaust gas increases. Thus, the PSA 81 is provided with flue gas having an increased hydrogen content. The PSA 81 discharges only hydrogen in the exhaust gas. Therefore, carbon monoxide, carbon dioxide, and nitrogen other than hydrogen are removed from the exhaust gas, and only hydrogen is supplied to the melt gasifier 10 by the PSA 81. Therefore, the hydrogen content in the reducing gas can be dramatically increased to increase the reduction rate of iron ore.

If carbon dioxide is adsorbed and removed with PSA, nitrogen is not adsorbed. Nitrogen is not used as a reducing gas, but diluting the reducing gas reduces the reduction rate of iron ore. When nitrogen is adsorbed by PSA, carbon monoxide, which has similar adsorption power to nitrogen, is also adsorbed and carbon monoxide required for iron ore reduction is also removed. However, in the fourth embodiment of the present invention, since the exhaust gas passes through the WGSR 70 and the hydrogen content of the exhaust gas is increased and the amount of carbon monoxide is very small, the carbon monoxide may be removed together with nitrogen using the PSA 81.

6 schematically shows a molten iron manufacturing apparatus 500 according to a fifth embodiment of the present invention. Since the apparatus for manufacturing molten iron 500 of FIG. 6 is similar to the apparatus for manufacturing molten iron 400 of FIG. 5, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted.

As shown in FIG. 6, the gas compressor 55 is located at the front end of the WGSR 70. The gas compressor 55 boosts the exhaust gas and reforms the WGSR 70. Therefore, the compressed flue gas is supplied to the WGSR 70 to increase the reaction rate of carbon monoxide and water. Thus, the WGSR 70 can produce hydrogen and carbon dioxide more efficiently.

The exhaust gas is separated into hydrogen and components other than hydrogen while passing through the PSA 81. Hydrogen is exhausted from the PSA 81 and supplied to the molten gasifier 10, and components other than hydrogen are removed. Therefore, since the hydrogen content in the reducing gas is dramatically increased, the reduction rate of iron ore can be increased.

7 schematically shows a molten iron manufacturing apparatus 600 according to a sixth embodiment of the present invention. Since the apparatus for manufacturing molten iron 600 of FIG. 7 is similar to the apparatus for manufacturing molten iron 100 of FIG. 1, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted. In addition, since the steam blower 90 is the same as the steam blower 90 of FIG. 4, the same reference numerals are used and detailed description thereof will be omitted.

As illustrated in FIG. 7, iron oxide acts as a catalyst by the steam blower 90 to react the steam blown with carbon monoxide in the reducing gas. Therefore, the content of hydrogen and carbon dioxide in the reducing gas is increased. The increased hydrogen passes through the first flow reduction path 24 and is exhausted through the exhaust gas pipe 50. As the exhaust gas passes through the WGSR 70, the contents of hydrogen and carbon dioxide in the exhaust gas are increased. That is, since hydrogen is generated twice while passing through the steam blower 90 and the WGSR 70, the content of hydrogen in the exhaust gas is further increased. Here, since carbon dioxide is adsorbed and removed by the PSA 80, the hydrogen content of the exhaust gas supplied to the melt gasifier 10 is very high.

8 schematically shows a molten iron manufacturing apparatus 700 according to a seventh embodiment of the present invention. Since the apparatus for manufacturing molten iron 700 of FIG. 8 is similar to the apparatus for manufacturing molten iron 200 of FIG. 3, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted. In addition, since the steam blower 90 is the same as the steam blower 90 of FIG. 4, the same reference numerals are used, and detailed description thereof will be omitted.

As shown in FIG. 8, the content of hydrogen in the reducing gas and the content of carbon dioxide are increased by the steam blower 90. The reducing gas passes through the first flow reduction path 24 and then passes through the exhaust gas pipe 50 to be exhausted as exhaust gas. The exhaust gas is boosted while passing through the gas compressor 55. When the boosted exhaust gas is supplied to the WGSR 70, hydrogen and carbon dioxide may be generated more efficiently. Since hydrogen is generated twice while passing through the steam blower 90 and the WGSR 70, the hydrogen content in the exhaust gas is higher. Here, since carbon dioxide is adsorbed and removed by the PSA 80, the hydrogen content of the exhaust gas supplied to the melt gasifier 10 is very high.

9 schematically shows a molten iron manufacturing apparatus 800 according to an eighth embodiment of the present invention. Since the apparatus for manufacturing molten iron 800 of FIG. 9 is similar to the apparatus for manufacturing molten iron 400 illustrated in FIG. 5, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted. In addition, since the steam blower 90 is the same as the steam blower 90 of FIG. 4, the same reference numerals are used, and detailed description thereof will be omitted.

As shown in FIG. 9, the content of hydrogen and carbon dioxide in the reducing gas is increased by the steam blower 90. The reducing gas is exhausted as exhaust gas through the exhaust gas pipe 50 after passing through the first flow reduction path 24. Since hydrogen is produced twice while passing through the steam blower 90 and the WGSR 70, the hydrogen content in the exhaust gas is higher. And while the exhaust gas passes through the PSA 81, only hydrogen is supplied through the exhaust gas supply pipe 57 and the remaining components are removed. The PSA 81 supplies hydrogen to the melting gasifier 10 and removes carbon monoxide, carbon dioxide, nitrogen, and the like. Therefore, since the hydrogen content in the reducing gas is dramatically increased, the reduction rate of iron ore can be greatly increased.

10 schematically shows a molten iron manufacturing apparatus 900 according to a ninth embodiment of the present invention. Since the apparatus for manufacturing molten iron 900 of FIG. 10 is similar to the apparatus for manufacturing molten iron 500 of FIG. 6, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted. In addition, since the steam blower 90 is the same as the steam blower 90 of Figure 4, the same reference numerals are used and the detailed description thereof will be omitted.

As shown in FIG. 10, the content of hydrogen in the reducing gas and the content of carbon dioxide are increased by the steam blower 90. The reducing gas is exhausted as exhaust gas through the exhaust gas pipe 50 after passing through the first flow reduction path 24. The exhaust gas is boosted while passing through the gas compressor 55. As the boosted exhaust gas is supplied to the WGSR 70 and reformed, hydrogen and carbon dioxide may be generated more efficiently. That is, since hydrogen is generated twice while passing through the steam blower 90 and the WGSR 70, the content of hydrogen in the exhaust gas is further increased.

Next, while exhaust gas passes through PSA 81, components other than hydrogen are removed. Therefore, the PSA 81 supplies only hydrogen to the melting gasifier 10 and removes carbon monoxide, carbon dioxide, nitrogen, and the like. As a result, the hydrogen content in the reducing gas is dramatically increased to increase the reduction rate of iron ore.

11 schematically shows a molten iron manufacturing apparatus 1000 according to a tenth embodiment of the present invention. Since the apparatus for manufacturing molten iron 1000 of FIG. 11 is similar to the apparatus for manufacturing molten iron 100 of FIG. 1, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted.

As shown in FIG. 11, the reformed reducing gas passing through the WGSR 70 and the PSA 81 may be directly supplied to the melting gasifier 10. That is, the reducing gas may be directly supplied to the molten gasifier 10 together with oxygen through a tuyere (not shown) installed in the molten gasifier 10. Therefore, the exhaust gas is supplied to the fluidized bed reduction furnace 20 via the melt gasifier 10. In this case, the melting point of the iron ore melted in the melt gasifier 10 can be significantly lowered. That is, since the reformed gas is used to increase the hydrogen content, the melting point of the iron ore is significantly lowered. As a result, fuel cost can be greatly reduced at the time of manufacturing molten iron.

12 schematically shows a molten iron manufacturing apparatus 1100 according to an eleventh embodiment of the present invention. Since the apparatus for manufacturing molten iron 1100 of FIG. 12 is similar to the apparatus for manufacturing molten iron 100 of FIG. 1, the same reference numerals are used for the same parts, and a detailed description thereof will be omitted.

As shown in FIG. 12, the apparatus for manufacturing molten iron 1100 includes a packed-bed reduction reactor 22. Although not shown in FIG. 12, the apparatus for manufacturing molten iron may include a packed-bed reduction reactor and a fluidized-bed reduction reactor together. In addition, the molten iron manufacturing apparatus may be provided with a plurality of packed-bed reduction reactors. Iron ore is charged into the packed-bed reduction furnace 22, and the reducing gas generated from the molten gasifier 10 is supplied to the packed-bed reduction reactor 22 through a reducing gas supply pipe 40. In the packed-bed reduction furnace 22, iron ore is reduced by reducing gas. Therefore, iron ore is converted into reduced iron, and the reduced iron is charged into the molten gasifier 10 and melted by a coal packed bed formed by the bulk coal ash. This method can be used to produce molten iron.

The exhaust gas discharged from the packed-bed reduction reactor 22 passes through the WGSR 70 and the PSA 80. As the exhaust gas passes through the WGSR 70, the hydrogen content and carbon dioxide content in the exhaust gas increase. Next, the exhaust gas passes through the PSA 80 to remove carbon dioxide in the exhaust gas. Therefore, the hydrogen content in the exhaust gas supplied to the packed-bed reduction furnace 22 is very high. As a result, the reduction rate of iron ore in the packed-bed reduction furnace 22 can be greatly increased.

On the other hand, although not shown in Figure 12, the reformed exhaust gas may be directly supplied to the melt gasifier (10). In this case, the melting point of the iron ore is significantly lowered, which can greatly reduce the fuel cost during the production of 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  One

After charging the iron ore into the chamber having the same conditions as the melting gas furnace of Figure 11, by supplying a reducing gas to the chamber to measure the melting point of the iron ore according to the temperature rise of the chamber four times, the shape change of the iron ore was photographed . The reducing gas contained 33 vol% hydrogen and 67 vol% carbon monoxide.

Experimental Example  Experiment result of 1

13 shows the shape change of the iron ore according to Experimental Example 1.

As shown in FIG. 13, iron ore melted as the temperature in the chamber increased to 1300 ° C, 1400 ° C, 1430 ° C, and 1440 ° C. When the temperature in the chamber was 1300 ° C., there was no change in the shape of the iron ore. Iron ore began to melt slightly when the temperature in the chamber was 1400 ° C. Most of the iron ore was melted when the temperature in the chamber was 1430 ° C, and the iron ore was completely melted at 1440 ° C. Therefore, the melting point of iron ore in Experimental Example 1 was confirmed to 1400 ℃.

Comparative example  One

After charging the iron ore into the chamber having the same conditions as the melt gasifier of Figure 1, by supplying a reducing gas to the chamber and measuring the melting point of the iron ore according to the temperature rise of the chamber four times, the shape change of the iron ore was photographed . The reducing gas contained 100 vol% carbon monoxide.

Comparative example  Experiment result of 1

14 shows the shape change of the iron ore according to Comparative Example 1.

As shown in FIG. 14, iron ore melted as the temperature in the chamber increased to 1300 ° C, 1400 ° C, 1490 ° C, and 1500 ° C. When the temperatures in the chamber were 1300 ° C. and 1400 ° C., there was little change in the shape of the iron ore. Melting started from the inside of the iron ore when the temperature in the chamber was 1490 ° C, and the iron ore was completely melted at 1500 ° C. Therefore, the melting point of iron ore in Comparative Example 1 was confirmed to 1490 ℃.

Comparing Experimental Example 1 and Comparative Example 1 described above, the iron ore of Experimental Example 1 had a melting point about 90 ° C. lower than that of Comparative Example 1. In other words, the iron ore has a lower melting point when using a reducing gas containing hydrogen than when using a reducing gas of carbon monoxide. Therefore, it is possible to lower the melting point of iron ore by increasing the hydrogen content in the reducing gas. As a result, fuel cost can be greatly reduced at the time of manufacturing molten iron.

Experimental Example  2

The components of the exhaust gas before passing through the WGSR and the components of the exhaust gas after passing through the WGSR were examined using the WGSR of FIG. 1.

Experimental Example  2 experimental results

15 shows the compositional changes of the exhaust gas before and after the exhaust gas passes through the WGSR.

As shown in FIG. 15, the 1.0 L / min flue gas contained 20 vol% nitrogen, 30 vol% carbon dioxide, 20 vol% hydrogen, and 30 vol% carbon monoxide before passing through WGSR. The exhaust gas passing through the WGSR increased the total flow rate to 1.25 L / min and contained 16 vol% nitrogen, 45 vol% carbon dioxide, 38 vol% hydrogen, and 0.5 vol% carbon monoxide. That is, after passing through the WGSR, the flow rate of carbon dioxide and hydrogen in the exhaust gas and their content in the reducing gas increased. On the other hand, the flow rate of carbon monoxide in exhaust gas and the content in reducing gas were decreased. Nitrogen decreased in the reducing gas to 16 vol%, but the flow rate was the same as before passing through the WGSR.

As described above, when the exhaust gas passes through the WGSR, the content and flow rate of hydrogen and carbon dioxide in the exhaust gas are increased, respectively, and the content and flow rate of carbon monoxide are decreased. Therefore, using WGSR it was possible to increase the content of hydrogen contained in the exhaust gas.

Experimental Example  3

Using the PSA of FIG. 5, the components of the exhaust gas before passing through the PSA and the components of the exhaust gas after passing through the PSA were displayed.

Experimental Example  3, experimental results

Fig. 16 shows changes in the composition of the exhaust gas before and after the exhaust gas passes through the PSA. Here, PSA exhausts only the hydrogen in the exhaust gas and removes all remaining components.

As shown in FIG. 16, the exhaust gas before passing through PSA contains 16 vol% of nitrogen, 45 vol% of this carbon oxide, 38 vol% of hydrogen, and 0.5 vol% of carbon monoxide. The content of carbon dioxide and hydrogen in the flue gas was high. On the other hand, the exhaust gas passing through the PSA contained 3 vol% nitrogen and 97 vol% hydrogen. Therefore, PSA was able to maximize the hydrogen content in the exhaust gas.

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

1 is a view schematically showing a molten iron manufacturing apparatus according to a first embodiment of the present invention.

2 is a graph showing the reduction rate of iron ore according to the composition of the reducing gas.

3 is a view schematically showing a molten iron manufacturing apparatus according to a second embodiment of the present invention.

4 is a view schematically showing a molten iron manufacturing apparatus according to a third embodiment of the present invention.

5 is a view schematically showing a molten iron manufacturing apparatus according to a fourth embodiment of the present invention.

6 is a view schematically showing a molten iron manufacturing apparatus according to a fifth embodiment of the present invention.

7 is a view schematically showing a molten iron manufacturing apparatus according to a sixth embodiment of the present invention.

8 is a view schematically showing a molten iron manufacturing apparatus according to a seventh embodiment of the present invention.

9 is a view schematically showing a molten iron manufacturing apparatus according to an eighth embodiment of the present invention.

10 is a view schematically showing a molten iron manufacturing apparatus according to a ninth embodiment of the present invention.

11 is a view schematically showing a molten iron manufacturing apparatus according to a tenth embodiment of the present invention.

12 is a view schematically showing a molten iron manufacturing apparatus according to an eleventh embodiment of the present invention.

13 and 14 are photographs showing the molten state of iron ore according to Experimental Example 1 and Comparative Example 1, respectively.

15 is a graph showing a change in composition of the exhaust gas according to Experimental Example 2. FIG.

16 is a graph showing a change in composition of the exhaust gas according to Experimental Example 3.

Claims (27)

At least one reduction furnace for reducing iron ore to produce reduced iron, A molten gasification furnace connected with the reduction furnace to charge the reduced iron, the bulk carbon material is charged, and the oxygen is blown to produce molten iron, An exhaust gas supply pipe for circulating the exhaust gas discharged from the reduction furnace to the reduction furnace, One or more reformers installed in the flue gas supply pipe to increase the amount of hydrogen contained in the flue gas; A compressor installed in the exhaust gas supply pipe to compress the exhaust gas Including, The at least one reformer is a water gas shift reactor (WGSR) or a pressure swing absorber (PSA), The one or more reformers comprise a plurality of reformers, the plurality of reformers comprise WGSR and PSA, The compressor is a molten iron manufacturing apparatus located in front of or behind the WGSR parallel to the WGSR. delete delete delete The method of claim 1, The WGSR converts carbon monoxide contained in the exhaust gas into the hydrogen, and the PSA adsorbs carbon dioxide contained in the exhaust gas. The method of claim 5, The hydrogen passing through the WGSR is more than 38vol% and less than 100vol% of the exhaust gas manufacturing apparatus. The method of claim 1, The PSA is a molten iron manufacturing apparatus for extracting and exhausting hydrogen from the exhaust gas. The method of claim 7, wherein Hydrogen discharged from the PSA is more than 97vol% and less than 100vol% of the exhaust gas manufacturing apparatus. The method of claim 1, And a steam blower connected to the reduction furnace to blow steam into the reduction furnace. The method of claim 1, The reduction furnace is a molten iron manufacturing apparatus is a packed-bed reduction furnace or fluidized bed reduction furnace. The method of claim 1, When the reduction furnace is a fluidized bed reduction furnace, the at least one reduction furnace includes a plurality of flow reduction reactors, The plurality of flow reduction paths, A first flow reduction furnace for preheating the iron ore, A second flow reduction path connected to the first flow reduction path to preliminarily reduce the preheated iron ore, and A third flow reduction reactor connected to the second flow reduction reactor to finally reduce the preliminarily reduced iron ore; Including; The apparatus for manufacturing molten iron further includes a steam blower installed between the first flow reduction path and the second flow reduction path to blow steam into the first flow reduction path. The method of claim 1, And a reducing gas supply pipe for supplying the reducing gas discharged from the melt gasifier to the reducing furnace, wherein the reducing gas supply pipe is connected to the exhaust gas supply pipe. The method of claim 1, The exhaust gas supply pipe is installed in the molten gasifier to supply the exhaust gas to the molten gasifier through a tuyere that blows the oxygen, and the exhaust gas is circulated through the molten gasifier to the reduction furnace. Charging iron ore into a reduction furnace to produce reduced iron; Charging the lumped carbonaceous material into the melting gasifier, Charging the reduced iron into the melt gasifier; Manufacturing molten iron by injecting oxygen into the molten gasifier to melt the reduced iron; At least one reformer installed in an exhaust gas supply pipe connected to the reduction furnace to supply the exhaust gas discharged from the reduction furnace to reform the exhaust gas to increase the amount of hydrogen contained in the exhaust gas; Supplying the reformed exhaust gas to the reduction furnace and Compressing the exhaust gas by a compressor installed in the exhaust gas supply pipe; In the step of increasing the amount of hydrogen contained in the exhaust gas, The at least one reformer is a WGSR or PSA, the at least one reformer comprises a plurality of reformers, the plurality of reformers comprises a WGSR and a PSA, In the step of compressing the exhaust gas, The compressor is a molten iron manufacturing method located in the front or rear end of the WGSR parallel to the WGSR. delete delete delete The method of claim 14, And after the compressing the exhaust gas, increasing the amount of hydrogen contained in the exhaust gas. The method of claim 14, The WGSR converts carbon monoxide contained in the exhaust gas into the hydrogen, and the PSA adsorbs carbon dioxide contained in the exhaust gas. The method of claim 19, Hydrogen passing through the WGSR is more than 38vol% and less than 100vol% of the exhaust gas manufacturing method. The method of claim 14, The PSA is a molten iron manufacturing method for extracting and discharging hydrogen from the exhaust gas. The method of claim 21, Hydrogen discharged from the PSA is more than 97vol% and less than 100vol% of the exhaust gas manufacturing method. The method of claim 14, The method of manufacturing molten iron further comprising the step of blowing steam into the reduction furnace. The method of claim 23, wherein Preparing the reduced iron, Preheating the iron ore, Preliminarily reducing the preheated iron ore, and Finally reducing the preliminarily reduced iron ore Including, The steam is a molten iron manufacturing method used in the step of preheating the iron ore. The method of claim 14, In the step of producing the reduced iron, the reduction furnace molten iron manufacturing method is a packed-bed reduction furnace or fluidized bed reduction furnace. The method of claim 14, And supplying the reducing gas generated in the melt gasifier to the reduction furnace, wherein the reformed exhaust gas is mixed with the reducing gas to supply the reformed exhaust gas to the reduction furnace. Supply method of molten iron. The method of claim 14, In the manufacturing of the molten iron, the oxygen is supplied to the molten gasifier through the tuyere installed in the molten gasifier, and in the step of supplying the reformed exhaust gas to the reducing furnace, the reformed exhaust gas is the And the reformed exhaust gas is supplied to the reduction furnace through the melt gasifier and supplied to the melting furnace.

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