TW202340483A - Blast furnace operation method - Google Patents
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- TW202340483A TW202340483A TW111149331A TW111149331A TW202340483A TW 202340483 A TW202340483 A TW 202340483A TW 111149331 A TW111149331 A TW 111149331A TW 111149331 A TW111149331 A TW 111149331A TW 202340483 A TW202340483 A TW 202340483A
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- 238000000034 method Methods 0.000 title abstract description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 369
- 229910052742 iron Inorganic materials 0.000 claims abstract description 183
- 239000002994 raw material Substances 0.000 claims abstract description 133
- 239000000571 coke Substances 0.000 claims abstract description 96
- MUMGGOZAMZWBJJ-DYKIIFRCSA-N Testostosterone Chemical compound O=C1CC[C@]2(C)[C@H]3CC[C@](C)([C@H](CC4)O)[C@@H]4[C@@H]3CCC2=C1 MUMGGOZAMZWBJJ-DYKIIFRCSA-N 0.000 claims abstract description 14
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 38
- 239000000203 mixture Substances 0.000 claims description 33
- 238000011017 operating method Methods 0.000 claims description 27
- 239000002245 particle Substances 0.000 claims description 22
- 238000010586 diagram Methods 0.000 claims description 18
- 230000035699 permeability Effects 0.000 abstract description 21
- 239000007788 liquid Substances 0.000 abstract description 13
- 239000007789 gas Substances 0.000 description 208
- 238000006722 reduction reaction Methods 0.000 description 24
- 238000012360 testing method Methods 0.000 description 20
- 238000009423 ventilation Methods 0.000 description 17
- 238000002844 melting Methods 0.000 description 11
- 230000008018 melting Effects 0.000 description 11
- 239000000463 material Substances 0.000 description 9
- 239000003245 coal Substances 0.000 description 6
- 229910052739 hydrogen Inorganic materials 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000001965 increasing effect Effects 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 238000005255 carburizing Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000012768 molten material Substances 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 239000005431 greenhouse gas Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B5/00—Making pig-iron in the blast furnace
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture Of Iron (AREA)
Abstract
Description
本發明是有關於一種使風口前的高爐內產生高濃度還原氣體的高爐操作方法，詳細而言，是有關於一種提高高爐內的熔著帶及滴落帶中的金屬鐵的通液性、以及高爐內氣體的通氣性的高爐操作方法。The present invention relates to a blast furnace operating method that generates high-concentration reducing gas in the blast furnace before the tuyere. Specifically, it relates to a method for improving the liquid permeability of metallic iron in the melting zone and dripping zone in the blast furnace. and blast furnace operating methods for gas permeability within the blast furnace.
近年來，削減作為溫室效應氣體之一的CO 2氣體（二氧化碳氣體）的排放量的動態高漲。於利用高爐進行的煉鐵法中，使用炭材作為還原材料，因此產生大量的CO 2氣體。因此，鋼鐵業於CO 2氣體的排放量中成為主要的產業之一，必須響應削減CO 2氣體的排放量這一社會要求。具體而言，高爐操作中的源自煤炭的還原材料比的進一步削減已成為當務之急。所謂源自煤炭的還原材料比，是指製造1噸熔鐵所需的源自煤炭的焦炭及源自煤炭的還原氣體的合計質量。 In recent years, there has been an increasing trend to reduce the emission of CO 2 gas (carbon dioxide gas), which is one of the greenhouse gases. In the iron-making method using a blast furnace, carbon material is used as a reducing material, so a large amount of CO 2 gas is generated. Therefore, the steel industry has become one of the major industries in terms of CO 2 gas emissions and must respond to the social demand for reducing CO 2 gas emissions. Specifically, further reduction in the ratio of coal-derived reducing materials in blast furnace operations has become a top priority. The ratio of coal-derived reducing materials refers to the total mass of coal-derived coke and coal-derived reducing gas required to produce 1 ton of molten iron.
還原材料具有於爐內變成熱而使裝入物升溫的作用、以及將爐內的作為鐵系原料的鐵礦石、鐵礦石的燒結礦、鐵礦石的顆粒還原的作用。為了降低還原材料比以削減CO 2氣體的排放量，需要一邊保持爐內的熱量，一邊提高還原材料的還原效率。 The reducing material has the function of turning into heat in the furnace to raise the temperature of the charge, and the function of reducing iron ore, iron ore sinter, and iron ore particles that are iron-based raw materials in the furnace. In order to lower the reducing material ratio and reduce CO2 gas emissions, it is necessary to increase the reduction efficiency of the reducing material while maintaining the heat in the furnace.
作為以削減CO 2氣體的排放量為目的的還原材料，氫備受矚目。利用氫進行的鐵礦石的還原為吸熱反應，但其吸熱量小於直接還原反應（反應式：FeO+C→Fe+CO），基於氫的還原速度快於基於CO氣體的還原速度。因此，藉由向高爐吹入氫系氣體，可同時實現CO 2氣體的排放量的削減以及還原效率的提高。 Hydrogen is attracting attention as a reducing material aimed at reducing CO 2 gas emissions. The reduction of iron ore using hydrogen is an endothermic reaction, but its heat absorption is smaller than that of the direct reduction reaction (reaction formula: FeO+C→Fe+CO). The reduction speed based on hydrogen is faster than the reduction speed based on CO gas. Therefore, by blowing hydrogen-based gas into the blast furnace, it is possible to simultaneously reduce CO 2 gas emissions and improve reduction efficiency.
為了高爐的穩定操作，需要確保高爐內的鐵系原料熔著的熔著帶的通氣性。但是，於使風口前的爐內產生高濃度還原氣體的高爐操作、以及較先前的操作而言爐內還原氣體濃度高並且還原反應速度快的高爐操作中，高爐內的通氣性並不清楚。In order to operate the blast furnace stably, it is necessary to ensure the permeability of the melting zone where the iron-based raw materials are melted in the blast furnace. However, in blast furnace operations in which a high concentration of reducing gas is generated in the furnace in front of the tuyere, and in blast furnace operations in which the concentration of reducing gas in the furnace is higher and the reduction reaction rate is faster than in previous operations, the ventilation in the blast furnace is not clear.
於利用氫進行還原時，與CO氣體還原時相比，鐵系原料的還原率變高。因此，即便於高還原率時的高爐操作中，亦需要於可確保適當的金屬鐵（經還原而生成的金屬鐵）的通液性及氣體通氣性的原料裝入條件下進行操作。When reduction is performed using hydrogen, the reduction rate of the iron-based raw material becomes higher compared to when reduction is performed with CO gas. Therefore, even when operating a blast furnace at a high reduction rate, it is necessary to operate under raw material charging conditions that ensure appropriate liquid permeability and gas permeability of metallic iron (metal iron produced by reduction).
作為用於解決與所述課題類似的問題的現有技術，提出有專利文獻1、專利文獻2中所揭示的技術。As conventional technologies for solving problems similar to the above-mentioned problems, technologies disclosed in Patent Document 1 and Patent Document 2 have been proposed.
於專利文獻1中，揭示有一種裝入物分佈控制方法，其中於礦石層/焦炭層的周邊區域中的相對層厚比為0.50～0.70的高爐中，可靠且準確地調整爐頂裝入物沿爐口半徑方向的裝入模式，從而實現高爐的穩定操作。Patent Document 1 discloses a charging material distribution control method in which the furnace top charging material is reliably and accurately adjusted in a blast furnace in which the relative layer thickness ratio in the peripheral area of the ore layer/coke layer is 0.50 to 0.70. Loading pattern along the radius of the furnace mouth, thereby achieving stable operation of the blast furnace.
於專利文獻2中，揭示有一種高爐操作方法，其中於自風口吹入相對於每噸熔鐵而為180 kg以上的粉煤的高爐操作中，以使焦炭層厚Lc、與將焦炭層厚Lc及礦石層厚Lo加以合計而得的裝入層厚的比在爐半徑方向上的各區域中滿足規定值的方式，自爐頂裝入焦炭及鐵礦石。根據專利文獻2，可降低高爐上部的裝入物層中的壓力損失，良好地保持爐內通氣性，能夠進行穩定的高粉煤吹入操作。 [現有技術文獻] [專利文獻] Patent Document 2 discloses a blast furnace operation method in which 180 kg or more of pulverized coal per ton of molten iron is blown from a tuyere so that the coke layer thickness Lc and the coke layer thickness are Coke and iron ore are charged from the top of the furnace so that the ratio of the charged layer thickness obtained by adding the total of Lc and the ore layer thickness Lo satisfies a prescribed value in each area in the furnace radial direction. According to Patent Document 2, the pressure loss in the charge layer in the upper part of the blast furnace can be reduced, the ventilation in the furnace can be maintained well, and a stable high-pulverized coal injection operation can be performed. [Prior Art Document] [Patent Document]
專利文獻1：日本專利特開2000-256712號公報 專利文獻2：日本專利特開2002-129211號公報 Patent Document 1: Japanese Patent Application Laid-Open No. 2000-256712 Patent Document 2: Japanese Patent Application Publication No. 2002-129211
[發明所欲解決之課題] 但是，該些現有技術均是將鐵系原料的還原率低的條件下的操作設為對象的技術。因此，該些現有技術對於消除如下高爐操作、即、使風口前的高爐內產生高濃度還原氣體來提高鐵系原料的還原率，因此金屬鐵的通液性惡化而產生熔著帶中的通氣性的降低的高爐操作而言無效。 [Problem to be solved by the invention] However, these conventional technologies all target operations under conditions in which the reduction rate of iron-based raw materials is low. Therefore, these prior art techniques eliminate the following blast furnace operations, that is, generating high-concentration reducing gas in the blast furnace before the tuyere to increase the reduction rate of iron-based raw materials, thereby deteriorating the liquid permeability of metallic iron and causing ventilation in the welding zone. Ineffective for reducing blast furnace operation.
即，於以風口前的爐內產生的高濃度還原氣體成為圖1（圖1的說明將於以後敘述）的區域A的範圍內（包含H 2氣體=0體積%～100體積%、N 2氣體=0體積%～71體積%、CO氣體=0體積%～100體積%的範圍內）的方式進行操作時，比先前的操作更促進鐵系原料自低溫的還原，因此到達還原率變高。藉此，高爐內所生成的金屬鐵量增加。 That is, the high-concentration reducing gas generated in the furnace in front of the tuyere falls within the range of area A in Figure 1 (the description of Figure 1 will be described later) (including H 2 gas = 0 volume % to 100 volume %, N 2 When the operation is performed in the range of gas = 0 volume % to 71 volume %, CO gas = 0 volume % to 100 volume %), the reduction of iron-based raw materials from low temperature is promoted more than the previous operation, so the reduction rate becomes higher. . Thereby, the amount of metallic iron produced in the blast furnace increases.
鐵（Fe）的熔點為1538℃，比FeO的熔點即1377℃高。因此，於先前的操作方法的原材料裝入方法中，存在金屬鐵的通液性降低，應滴落到爐床部的金屬鐵會滯留於焦炭層的空隙中的問題。因此，高爐內的通氣阻力增加，有可能會誘發竄氣。The melting point of iron (Fe) is 1538°C, which is higher than the melting point of FeO, which is 1377°C. Therefore, in the raw material charging method of the previous operating method, there is a problem that the liquid permeability of the metallic iron is reduced, and the metallic iron that should drip to the hearth portion is retained in the gaps of the coke layer. Therefore, the ventilation resistance in the blast furnace increases, possibly inducing blow-by gas.
本發明是鑒於所述情況而成，其目的在於提供一種高爐操作方法，其於實施使風口前的爐內產生高濃度還原氣體的高爐操作時，可在高爐內的熔著帶及滴落帶適當地保持金屬鐵的通液性，並將高爐內的氣體通氣性確保為能夠操作的範圍內。 [解決課題之手段] The present invention was made in view of the above situation, and its object is to provide a blast furnace operating method that can operate the blast furnace in which a high-concentration reducing gas is generated in the furnace in front of the tuyere. The liquid permeability of metallic iron is appropriately maintained, and the gas permeability in the blast furnace is ensured within an operable range. [Means to solve the problem]
為了解決所述課題，本發明者等人進行了努力研究。結果，獲得如下見解：於使風口前的高爐內產生高濃度還原氣體的高爐操作中，控制鐵系原料與焦炭的邊界面積，增加焦炭中的碳向爐內生成的金屬鐵的滲碳面積，並藉由碳的滲碳來促進金屬鐵的熔點降低；藉此，良好地保持高爐內的熔著帶及滴落帶中的金屬鐵的通液性及氣體通氣性。本發明是基於所述見解而成，其主旨如以下般。In order to solve the above-mentioned problems, the inventors of the present invention have conducted diligent research. As a result, the following findings were obtained: In a blast furnace operation in which a high-concentration reducing gas is generated in the blast furnace in front of the tuyere, the boundary area between the iron-based raw material and the coke can be controlled to increase the carburizing area of the carbon in the coke to the metallic iron generated in the furnace. It also promotes the lowering of the melting point of metallic iron through carburization of carbon; thus, the liquid permeability and gas permeability of metallic iron in the melting zone and dripping zone in the blast furnace are well maintained. The present invention is based on the above findings, and its gist is as follows.
[1] 一種高爐操作方法，自高爐的爐頂交替裝入鐵系原料以及焦炭，並自高爐的風口吹入使風口前的爐內產生高濃度還原氣體的氣體，所述高爐操作方法將所述鐵系原料與所述焦炭的每單位鐵系原料的邊界面積設為規定範圍內。 [2] 如[1]所述的高爐操作方法，其中所述每單位鐵系原料的邊界面積為每單位鐵系原料的鐵系原料層與焦炭層的邊界面積、和鐵系原料與混合裝入至鐵系原料層的焦炭粒子的邊界面積的合計值。 [3] 如[2]所述的高爐操作方法，其中將所述每單位鐵系原料的邊界面積設為25 m 2/礦石-噸以上。 [4] 如[1]所述的高爐操作方法，其中所述高濃度還原氣體於以爐腹氣體（Bosh gas）組成來表示時為如下組成、即包含H 2氣體、N 2氣體及CO氣體、且H 2氣體、N 2氣體及CO氣體的比例處於H 2氣體-N 2氣體-CO氣體的三元系圖表中的由H 2氣體：0體積%、N 2氣體：0體積%、CO氣體：100體積%的點、H 2氣體：100體積%、N 2氣體：0體積%、CO氣體：0體積%的點、H 2氣體：29體積%、N 2氣體：71體積%、CO氣體：0體積%的點、以及H 2氣體：0體積%、N 2氣體：37體積%、CO氣體：63體積%的點此四點包圍的區域內的組成，且包含0體積%～100體積%的範圍內的H 2氣體、0體積%～71體積%的範圍內的N 2氣體、以及0體積%～100體積%的範圍內的CO氣體。 [5] 如[2]所述的高爐操作方法，其中所述高濃度還原氣體於以爐腹氣體組成來表示時為如下組成、即包含H 2氣體、N 2氣體及CO氣體、且H 2氣體、N 2氣體及CO氣體的比例處於H 2氣體-N 2氣體-CO氣體的三元系圖表中的由H 2氣體：0體積%、N 2氣體：0體積%、CO氣體：100體積%的點、H 2氣體：100體積%、N 2氣體：0體積%、CO氣體：0體積%的點、H 2氣體：29體積%、N 2氣體：71體積%、CO氣體：0體積%的點、以及H 2氣體：0體積%、N 2氣體：37體積%、CO氣體：63體積%的點此四點包圍的區域內的組成，且包含0體積%～100體積%的範圍內的H 2氣體、0體積%～71體積%的範圍內的N 2氣體、以及0體積%～100體積%的範圍內的CO氣體。 [6] 如[3]所述的高爐操作方法，其中所述高濃度還原氣體於以爐腹氣體組成來表示時為如下組成、即包含H 2氣體、N 2氣體及CO氣體、且H 2氣體、N 2氣體及CO氣體的比例處於H 2氣體-N 2氣體-CO氣體的三元系圖表中的由H 2氣體：0體積%、N 2氣體：0體積%、CO氣體：100體積%的點、H 2氣體：100體積%、N 2氣體：0體積%、CO氣體：0體積%的點、H 2氣體：29體積%、N 2氣體：71體積%、CO氣體：0體積%的點、以及H 2氣體：0體積%、N 2氣體：37體積%、CO氣體：63體積%的點此四點包圍的區域內的組成，且包含0體積%～100體積%的範圍內的H 2氣體、0體積%～71體積%的範圍內的N 2氣體、以及0體積%～100體積%的範圍內的CO氣體。 [7] 如[1]至[6]中任一項所述的高爐操作方法，其中所述高濃度還原氣體中的H 2量為0 Nm 3/熔鐵-噸～500 Nm 3/熔鐵-噸的範圍內。 [發明的效果] [1] A blast furnace operating method that alternately charges iron-based raw materials and coke from the top of the blast furnace, and blows gas from the tuyere of the blast furnace to generate a high-concentration reducing gas in the furnace in front of the tuyere. The boundary area per unit of iron-based raw material between the iron-based raw material and the coke is set to be within a predetermined range. [2] The blast furnace operating method according to [1], wherein the boundary area per unit of iron-based raw material is the boundary area between the iron-based raw material layer and the coke layer per unit of iron-based raw material, and the boundary area between the iron-based raw material and the mixing device. The total value of the boundary area of coke particles entering the iron-based raw material layer. [3] The blast furnace operating method according to [2], wherein the boundary area per unit of iron-based raw material is set to 25 m 2 /ore-ton or more. [4] The blast furnace operating method as described in [1], wherein the high-concentration reducing gas has the following composition when represented by the composition of bosh gas (Bosh gas), that is, including H 2 gas, N 2 gas and CO gas , and the proportions of H 2 gas, N 2 gas and CO gas are in the ternary system diagram of H 2 gas - N 2 gas - CO gas: H 2 gas: 0 volume %, N 2 gas: 0 volume %, CO Gas: 100 volume % point, H 2 gas: 100 volume %, N 2 gas: 0 volume %, CO gas: 0 volume % point, H 2 gas: 29 volume %, N 2 gas: 71 volume %, CO Gas: 0 volume % point, H 2 gas: 0 volume %, N 2 gas: 37 volume %, CO gas: 63 volume % point. The composition of the area surrounded by these four points, and contains 0 volume % to 100 H 2 gas in the range of volume %, N 2 gas in the range of 0 volume % to 71 volume %, and CO gas in the range of 0 volume % to 100 volume %. [5] The blast furnace operating method as described in [2], wherein the high-concentration reducing gas has the following composition when expressed as a furnace gas composition, that is, it contains H 2 gas, N 2 gas and CO gas, and H 2 The proportions of gas, N 2 gas and CO gas are in the ternary system diagram of H 2 gas - N 2 gas - CO gas: H 2 gas: 0 volume %, N 2 gas: 0 volume %, CO gas: 100 volume % point, H 2 gas: 100 volume %, N 2 gas: 0 volume %, CO gas: 0 volume % point, H 2 gas: 29 volume %, N 2 gas: 71 volume %, CO gas: 0 volume % point, H 2 gas: 0 volume %, N 2 gas: 37 volume %, CO gas: 63 volume %, and the composition in the area surrounded by these four points, and includes the range of 0 volume % to 100 volume %. H 2 gas in the range, N 2 gas in the range of 0 volume % to 71 volume %, and CO gas in the range of 0 volume % to 100 volume %. [6] The blast furnace operating method as described in [3], wherein the high-concentration reducing gas has the following composition when expressed as a furnace gas composition, that is, it contains H 2 gas, N 2 gas and CO gas, and H 2 The proportions of gas, N 2 gas and CO gas are in the ternary system diagram of H 2 gas - N 2 gas - CO gas: H 2 gas: 0 volume %, N 2 gas: 0 volume %, CO gas: 100 volume % point, H 2 gas: 100 volume %, N 2 gas: 0 volume %, CO gas: 0 volume % point, H 2 gas: 29 volume %, N 2 gas: 71 volume %, CO gas: 0 volume % point, H 2 gas: 0 volume %, N 2 gas: 37 volume %, CO gas: 63 volume %, and the composition in the area surrounded by these four points, and includes the range of 0 volume % to 100 volume %. H 2 gas in the range, N 2 gas in the range of 0 volume % to 71 volume %, and CO gas in the range of 0 volume % to 100 volume %. [7] The blast furnace operating method according to any one of [1] to [6], wherein the amount of H2 in the high-concentration reducing gas is 0 Nm 3 /molten iron-ton ~ 500 Nm 3 /molten iron-ton -ton range. [Effects of the invention]
於本發明中，在實施使風口前的爐內產生高濃度還原氣體的高爐操作時，將自爐頂裝入的鐵系原料與焦炭的每單位鐵系原料的邊界面積設為規定範圍內。藉此，所生成的金屬鐵的滲碳得到促進，金屬鐵的熔點降低，並且恰當地保持高爐內的熔著帶及滴落帶中的金屬鐵的通液性。結果，可將高爐內的氣體通氣性確保為能夠操作的範圍內，可實現高爐的穩定操作。In the present invention, when performing a blast furnace operation in which a high-concentration reducing gas is generated in the furnace before the tuyere, the boundary area per unit of the iron-based raw material and coke charged from the furnace top is within a predetermined range. Thereby, carburization of the generated metallic iron is promoted, the melting point of the metallic iron is lowered, and the liquid permeability of the metallic iron in the molten zone and the dripping zone in the blast furnace is appropriately maintained. As a result, the gas permeability in the blast furnace can be ensured within an operable range, and stable operation of the blast furnace can be achieved.
以下，具體說明本發明的實施形態。本實施形態的高爐操作方法為如下高爐操作方法，其自高爐的爐頂將鐵系原料以及焦炭交替且呈層狀地裝入至高爐內，並且自設置於高爐下部的風口向高爐內吹入氣體，利用自風口吹入的氣體使風口前的高爐內生成高濃度還原氣體。鐵系原料中例如包含鐵礦石、鐵礦石的燒結礦、鐵礦石的顆粒、還原鐵及廢鐵。使用的鐵系原料以及焦炭的種類並無特別限制，若為先前的高爐操作中所使用的鐵系原料以及焦炭，則於本發明中亦可適宜地使用。Hereinafter, embodiments of the present invention will be described in detail. The blast furnace operating method of this embodiment is a blast furnace operating method in which iron-based raw materials and coke are alternately charged into the blast furnace in layers from the top of the blast furnace, and are blown into the blast furnace from tuyeres provided at the lower part of the blast furnace. Gas, the gas blown from the tuyere is used to generate high-concentration reducing gas in the blast furnace in front of the tuyere. Iron-based raw materials include, for example, iron ore, iron ore sinter, iron ore particles, reduced iron, and scrap iron. The types of iron-based raw materials and coke used are not particularly limited. If they are iron-based raw materials and coke used in previous blast furnace operations, they can also be suitably used in the present invention.
用於生成高濃度還原氣體的氣體包含將高爐內的鐵系原料還原的還原成分。此處，所謂將高爐內的鐵系原料還原的還原成分，不僅包含其自身可將鐵系原料還原的成分即CO氣體、H 2氣體、烴氣體，而且亦包含藉由與焦炭的反應或分解反應等而生成還原氣體的成分即CO 2氣體、H 2O氣體等。 The gas used to generate the high-concentration reducing gas contains reducing components that reduce the iron-based raw materials in the blast furnace. Here, the reducing components that reduce the iron-based raw materials in the blast furnace include not only components that can reduce the iron-based raw materials by themselves, that is, CO gas, H 2 gas, and hydrocarbon gases, but also components that reduce the iron-based raw materials through reaction or decomposition with coke. CO 2 gas, H 2 O gas, etc. are components that generate reducing gases through reactions.
圖1是於H 2氣體-N 2氣體-CO氣體的三元系圖表的氣體成分組成中，表示藉由本實施形態的高爐操作方法使風口前的爐內生成的高濃度還原氣體的成分範圍的圖。所謂本實施形態中的高濃度還原氣體，為使用該高濃度還原氣體將鐵系原料於900℃下還原180分鐘時的平均還原率為80%以上的還原氣體。於以爐腹氣體組成表示該還原氣體時，為如下組成、即包含H 2氣體、N 2氣體以及CO氣體、且H 2氣體、N 2氣體以及CO氣體的比例（其中，設為H 2氣體+N 2氣體+CO氣體=100體積%時的比例）為圖1中斜線部所表示的區域A（本發明的操作範圍）的範圍內、並且包含0體積%～100體積%的範圍內的H 2氣體、0體積%～71體積%的範圍內的N 2氣體、以及0體積%～100體積%的範圍內的CO氣體的氣體組成。 Fig. 1 shows the composition range of the high-concentration reducing gas generated in the furnace before the tuyere by the blast furnace operating method of this embodiment in the gas component composition of the ternary system diagram of H 2 gas-N 2 gas-CO gas. Figure. The high-concentration reducing gas in this embodiment is a reducing gas with an average reduction rate of 80% or more when the iron-based raw material is reduced at 900° C. for 180 minutes using the high-concentration reducing gas. When the reducing gas is expressed as a furnace gas composition, it is a composition including H 2 gas, N 2 gas and CO gas, and the ratio of H 2 gas, N 2 gas and CO gas (where H 2 gas is + N 2 gas + CO gas = 100 volume %) is within the range of area A (the operating range of the present invention) indicated by the hatched portion in Figure 1 and includes the range of 0 volume % to 100 volume % The gas composition is H 2 gas, N 2 gas in the range of 0 volume % to 71 volume %, and CO gas in the range of 0 volume % to 100 volume %.
區域A為於H 2氣體-N 2氣體-CO氣體的三元系圖表中，由點O（H 2氣體：0體積%、N 2氣體：0體積%、CO氣體：100體積%）、點P（H 2氣體：100體積%、N 2氣體：0體積%、CO氣體：0體積%）、點Q（H 2氣體：29體積%、N 2氣體：71體積%、CO氣體：0體積%）及點R（H 2氣體：0體積%、N 2氣體：37體積%、CO氣體：63體積%）此四點包圍的範圍內。另外，圖1中比較示出先前的一般的高爐操作範圍的氣體組成。 Area A is in the ternary system diagram of H 2 gas-N 2 gas-CO gas, consisting of point O (H 2 gas: 0 volume %, N 2 gas: 0 volume %, CO gas: 100 volume %), point P ( H gas: 100 volume %, N gas: 0 volume %, CO gas: 0 volume %), point Q ( H gas: 29 volume %, N gas: 71 volume %, CO gas: 0 volume %) and point R (H 2 gas: 0 volume %, N 2 gas: 37 volume %, CO gas: 63 volume %) within the range surrounded by these four points. In addition, the gas composition in the previous general blast furnace operating range is comparatively shown in FIG. 1 .
於該區域A中的由點O（H 2氣體：0體積%、N 2氣體：0體積%、CO氣體：100體積%）、點P（H 2氣體：100體積%、N 2氣體：0體積%、CO氣體：0體積%）、點Q'（H 2氣體：43體積%、N 2氣體：57體積%、CO氣體：0體積%）及點R'（H 2氣體：0體積%、N 2氣體：14體積%、CO氣體：86體積%）此四點包圍的範圍內，將鐵系原料於900℃下還原180分鐘時的平均還原率為90%以上，因此爐內的熔著帶中的熔渣成分中的FeO量明顯降低。因此，於使風口前的爐內生成該成分範圍內的高濃度還原氣體時，將鐵系原料與焦炭的每單位鐵系原料的邊界面積設為規定範圍內，恰當地保持金屬鐵的通液性的效果進一步變高。 In this area A, point O (H 2 gas: 0 volume %, N 2 gas: 0 volume %, CO gas: 100 volume %), point P (H 2 gas: 100 volume %, N 2 gas: 0 Volume %, CO gas: 0 volume %), point Q' (H 2 gas: 43 volume %, N 2 gas: 57 volume %, CO gas: 0 volume %) and point R' (H 2 gas: 0 volume % , N 2 gas: 14 volume %, CO gas: 86 volume %) Within the range surrounded by these four points, the average reduction rate when the iron-based raw materials are reduced at 900°C for 180 minutes is more than 90%, so the melt in the furnace The amount of FeO in the slag component in the belt is significantly reduced. Therefore, when generating a high-concentration reducing gas within the composition range in the furnace before the tuyere, the boundary area per unit iron-based raw material of the iron-based raw material and coke is set within a predetermined range to appropriately maintain the flow of metallic iron. The effect of sex becomes even higher.
本發明者等人使用模擬高爐的比例尺1/4的小型試驗爐，進行使風口前的爐內產生高濃度還原氣體的試驗，進行對爐內的熔著帶及滴落帶中的鐵系原料與焦炭的邊界面積、和金屬鐵（經還原而生成的金屬）的滴落量的關係進行調查的試驗。此處，所謂鐵系原料與焦炭的邊界面積，是指將鐵系原料層與焦炭層的邊界面積S、和鐵系原料與混合裝入至鐵系原料層的焦炭粒子的邊界面積S mix加以合計而得的邊界面積S total即（S total=S+S mix）。 The present inventors used a small test furnace with a scale of 1/4 that simulated a blast furnace to conduct a test to generate a high-concentration reducing gas in the furnace in front of the tuyere, and tested the iron-based raw materials in the melting zone and dripping zone in the furnace. An experiment to investigate the relationship between the boundary area of coke and the dripping amount of metallic iron (metal produced by reduction). Here, the boundary area between the iron-based raw material and coke refers to the boundary area S between the iron-based raw material layer and the coke layer, and the boundary area S mix between the iron-based raw material and the coke particles mixed and charged into the iron-based raw material layer. The total boundary area S total is (S total =S+S mix ).
圖2是示意性地表示爐內的鐵系原料層及焦炭層的形狀的圖。如圖2所示，確認到鐵系原料層及焦炭層保持層狀在高爐內下降。該情況下，鐵系原料層與焦炭層的邊界成為鐵系原料層下表面與焦炭層上表面的邊界（圖2的邊界1）、以及鐵系原料層上表面與焦炭層下表面的邊界（圖2的邊界2）此兩處邊界。邊界1及邊界2的面積相等，藉由下述（1）式算出鐵系原料層與焦炭層的邊界面積S。FIG. 2 is a diagram schematically showing the shapes of the iron-based raw material layer and the coke layer in the furnace. As shown in Figure 2, it was confirmed that the iron-based raw material layer and the coke layer were descending in the blast furnace while maintaining their layered shape. In this case, the boundary between the iron-based raw material layer and the coke layer becomes the boundary between the lower surface of the iron-based raw material layer and the upper surface of the coke layer (boundary 1 in FIG. 2 ), and the boundary between the upper surface of the iron-based raw material layer and the lower surface of the coke layer ( Boundary 2 in Figure 2) These two boundaries. The areas of boundary 1 and boundary 2 are equal, and the boundary area S between the iron-based raw material layer and the coke layer is calculated according to the following equation (1).
[數1] …（1） [Number 1] …(1)
於所述（1）式中，D為試驗爐的爐徑（m），θ為爐內裝入物（鐵系原料層及焦炭層）相對於水平線的傾斜角度（°），π為圓周率。爐徑D使用根據試驗爐的設計圖而得的爐腹徑，傾斜角度θ使用於爐內塊狀帶所測定的值。於鐵系原料層與焦炭層的邊界無法利用直線近似時，例如，在半徑方向上將邊界分割為多個區域，並使用各區域中的傾斜角度的平均值算出傾斜角度θ，以便能夠利用直線近似。In the formula (1), D is the furnace diameter (m) of the test furnace, θ is the inclination angle (°) of the furnace charge (iron-based raw material layer and coke layer) relative to the horizontal line, and π is the pi. The furnace diameter D is the furnace diameter obtained from the design drawing of the test furnace, and the inclination angle θ is the value measured for the block zone in the furnace. When the boundary between the iron-based raw material layer and the coke layer cannot be approximated by a straight line, for example, the boundary is divided into a plurality of regions in the radial direction and the inclination angle θ is calculated using the average of the inclination angles in each region so that a straight line can be used. approximate.
圖3的（A）是示意性地表示鐵系原料層與混合裝入至鐵系原料層的焦炭粒子的圖，圖3的（B）是示意性地表示混合裝入至鐵系原料層的焦炭粒子的形狀的圖。如圖3的（B）所示，將混合裝入至鐵系原料層中的焦炭粒子看作正八面體，藉此利用下述（2）式及（3）式算出鐵系原料與混合裝入至鐵系原料層的焦炭粒子的邊界面積S mix。 FIG. 3(A) is a diagram schematically showing an iron-based raw material layer and coke particles mixed and charged into the iron-based raw material layer. FIG. 3(B) is a diagram schematically showing a layer of coke particles mixed and charged into the iron-based raw material layer. Diagram of the shape of coke particles. As shown in FIG. 3(B) , the coke particles mixed and charged into the iron-based raw material layer are regarded as regular octahedrons, and the following formulas (2) and (3) are used to calculate the relationship between the iron-based raw material and the mixing device. The boundary area S mix of coke particles entering the iron-based raw material layer.
[數2] …（2） …（3） [Number 2] …(2) …(3)
於所述（2）式、（3）式中，a為正八面體的一邊的長度（m），W c為爐內的每1層鐵系原料層中所混合的混合焦炭的質量（噸/進料（ton/charge）），ρ c為焦炭的表觀密度（kg/m 3），d為混合焦炭的粒徑（m）。焦炭的表觀密度ρ c是基於包括粒子內的空隙在內的每單位容積的質量，利用液浸法進行測定。混合焦炭的粒徑d是設為自混合裝入層採集的焦炭的平均粒徑。 In the above formulas (2) and (3), a is the length of one side of the regular octahedron (m), and W c is the mass (tons) of the mixed coke mixed in each iron-based raw material layer in the furnace. /feed (ton/charge)), ρ c is the apparent density of coke (kg/m 3 ), and d is the particle size of mixed coke (m). The apparent density ρ c of coke is based on the mass per unit volume including the voids in the particles, and is measured by the liquid immersion method. The particle size d of the mixed coke is the average particle size of the coke collected from the mixed charging layer.
鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit由下述（4）式表示。 The boundary area S unit per unit of iron-based raw material and coke is represented by the following formula (4).
[式3] …（4） 於所述（4）式中，W Iron為爐內的每1層鐵系原料層的鐵系原料的質量（噸/進料）。 [Formula 3] ...(4) In the above formula (4), W Iron is the mass (ton/feed) of iron-based raw materials per iron-based raw material layer in the furnace.
所謂鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit，是計算出鐵系原料層下表面與焦炭層上表面的邊界面積和鐵系原料層上表面與焦炭層下表面的邊界面積，並且將在鐵系原料層中混合裝入焦炭粒子時的焦炭粒子看作正八面體，計算出與焦炭粒子數相應的正八面體的表面積作為鐵系原料與焦炭粒子的邊界面積，將兩者加以合計而獲得邊界面積S total，且邊界面積S total除以W Iron而得的值。 The boundary area S unit per unit iron-based raw material between the iron-based raw material and coke is calculated by calculating the boundary area between the lower surface of the iron-based raw material layer and the upper surface of the coke layer and the boundary area between the upper surface of the iron-based raw material layer and the lower surface of the coke layer. , and the coke particles when coke particles are mixed and charged into the iron-based raw material layer are regarded as regular octahedrons, and the surface area of the regular octahedron corresponding to the number of coke particles is calculated as the boundary area between the iron-based raw materials and the coke particles, and the two are added together to obtain the boundary area S total , and the boundary area S total is divided by W Iron .
於小型試驗爐中，進行如下試驗，即，將原料裝入條件設為現有方法的操作條件、且鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit為約14 m 2/礦石-噸的條件，並使風口前的爐內生成高濃度還原氣體。於該原料裝入條件下，熔著帶中的熔融物的滴落量減少至先前試驗的十分之一左右，因此通氣性劣化至能夠繼續穩定的試驗的範圍外。該情況示出必需重新設定與使風口前的爐內生成高濃度還原氣體的高爐操作相適的原料裝入條件。 In a small-scale test furnace, a test was conducted in which the raw material charging conditions were set to the operating conditions of the conventional method, and the boundary area S unit per unit of iron-based raw material and coke was approximately 14 m 2 /ore- tons of conditions, and generate high concentration reducing gas in the furnace in front of the tuyere. Under these raw material loading conditions, the dripping amount of the molten material in the bonding tape was reduced to about one-tenth of that in the previous test, so the air permeability was deteriorated beyond the range where stable testing could be continued. This situation shows that it is necessary to reset the raw material charging conditions suitable for the blast furnace operation in which high-concentration reducing gas is generated in the furnace in front of the tuyere.
基於在提高金屬鐵的通液性時需要增加對於高爐內經還原而生成的金屬鐵的滲碳面積的見解，進行如下試驗、即變更鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit並使小型試驗爐的風口前的爐內生成高濃度還原氣體。於該試驗中，使鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit於12 m 2/礦石-噸～35 m 2/礦石-噸的範圍內變更，調查每單位鐵系原料的邊界面積S unit對金屬鐵滴落量及通氣阻力指數KS造成的影響。 Based on the finding that it is necessary to increase the carburizing area of metallic iron produced by reduction in a blast furnace in order to improve the liquid permeability of metallic iron, an experiment was conducted to change the boundary area S unit of the iron-based raw material and coke per unit of the iron-based raw material. And generate high concentration reducing gas in the furnace in front of the tuyere of the small test furnace. In this test, the boundary area S unit per unit of iron-based raw material and coke was changed within the range of 12 m 2 /ore-ton to 35 m 2 /ore-ton, and the boundary area per unit of iron-based raw material was investigated. The impact of the boundary area S unit on the amount of metallic iron dripping and the ventilation resistance index KS.
關於金屬鐵滴落量，於實驗後回收試驗中滴落的熔融物，將金屬鐵與熔渣分離後，利用重量計測定金屬鐵的重量。通氣阻力指數KS是作為以在爐內溫度為1000℃以上的區域中測定的壓力損失、與根據操作條件推測的物性值為基礎而算出的通氣阻力K值（1/m）的積分值來算出。Regarding the amount of metallic iron dripping, the molten material dripping during the test was recovered after the experiment, the metallic iron and the slag were separated, and the weight of the metallic iron was measured using a gravimeter. The ventilation resistance index KS is calculated as the integrated value of the ventilation resistance K value (1/m) calculated based on the pressure loss measured in a region where the furnace temperature is 1000°C or higher and the physical property values estimated based on the operating conditions. .
＜通氣阻力指數KS的算出方法＞ 通氣阻力K值（1/m）是藉由下述（5）式來算出。 K=（ΔP/H）/（ρ gas 0.7×μ gas 0.3×v gas 1.7） …（5） 此處，ΔP為壓力損失（Pa），H為爐內填充層層厚（m），ρ gas為氣體密度（kg/m 3），μ gas為氣體黏度（Pa･s），v gas為氣體流速（m/s）。ΔP是藉由在風口與試驗爐上部（比填充層更靠上部的空間）的爐壁設置壓力計並計算壓力的差量而求出。關於H，自例如於試驗爐上部穿孔的孔***測定用夾具來測定填充層表面的位置，並使用填充層表面位置與設置有風口的位置於高度方向上的距離作為H。可使用雷射距離計測定填充層表面的位置。ρ gas可根據自風口導入的氣體成分、爐內的溫度、以及爐內的壓力來算出。μ gas可根據自風口導入的氣體成分、與爐內的溫度來算出。v gas可根據自風口導入的氣體流量、爐內的溫度、以及爐內的壓力來算出。此處，爐內的溫度是於與填充層對應的位置的爐壁設置多個溫度計，並使用該溫度計的測定值的平均值。同樣地，爐內的壓力是於與填充層對應的位置的爐壁設置多個壓力計，並使用該壓力計的測定值的平均值。亦可使用ΔP的算出中使用的風口的壓力與填充層上部的壓力的平均值作為爐內的壓力。 <Calculation method of ventilation resistance index KS> The ventilation resistance K value (1/m) is calculated by the following formula (5). K=(ΔP/H)/(ρ gas 0.7 ×μ gas 0.3 ×v gas 1.7 )…(5) Here, ΔP is the pressure loss (Pa), H is the thickness of the filling layer in the furnace (m), ρ gas is the gas density (kg/m 3 ), μ gas is the gas viscosity (Pa･s), and v gas is the gas flow rate (m/s). ΔP is found by installing a pressure gauge on the tuyere and the furnace wall at the upper part of the test furnace (the space above the filling layer) and calculating the pressure difference. Regarding H, for example, a measuring jig is inserted into a hole punched in the upper part of the test furnace to measure the position of the filling layer surface, and the distance in the height direction between the filling layer surface position and the position where the tuyere is installed is used as H. A laser distance meter can be used to determine the position of the filling layer surface. ρ gas can be calculated based on the gas composition introduced from the tuyere, the temperature in the furnace, and the pressure in the furnace. μ gas can be calculated based on the gas composition introduced from the tuyere and the temperature in the furnace. v gas can be calculated based on the gas flow rate introduced from the tuyere, the temperature in the furnace, and the pressure in the furnace. Here, the temperature in the furnace is determined by placing a plurality of thermometers on the furnace wall at a position corresponding to the filled layer, and using the average value of the measured values of the thermometers. Similarly, the pressure in the furnace is determined by installing a plurality of pressure gauges on the furnace wall at positions corresponding to the filling layer and using the average value of the measured values of the pressure gauges. The average value of the pressure at the tuyeres used for calculation of ΔP and the pressure at the upper part of the packed bed may be used as the pressure in the furnace.
通氣阻力指數KS是藉由下述（6）式來算出。The ventilation resistance index KS is calculated by the following equation (6).
[數4] …（6） 於（6）式中，Tmax為測定爐內壓力損失的最高溫度，雖然每次測定均不同，但為1500℃～1650℃左右。 [Number 4] …(6) In the formula (6), Tmax is the maximum temperature at which the pressure loss in the furnace is measured. Although it varies from measurement to measurement, it is approximately 1500°C to 1650°C.
圖4是表示金屬鐵滴落量、和鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit的關係的圖形。圖4的橫軸為鐵系原料與焦炭的每單位鐵系原料的邊界面積（m 2/礦石-噸），縱軸為無因次金屬鐵滴落量（-）。所謂無因次金屬鐵滴落量，是將每單位鐵系原料的邊界面積S unit為25 m 2/礦石-噸時的金屬鐵滴落量設為1.0的無因次的金屬鐵滴落量。單位（-）是指為無因次。 FIG. 4 is a graph showing the relationship between the amount of metallic iron dripping and the boundary area S unit per unit of iron-based raw material between the iron-based raw material and coke. The horizontal axis of Figure 4 is the boundary area per unit of iron-based raw material and coke (m 2 /ore-ton), and the vertical axis is the dimensionless metallic iron dripping amount (-). The dimensionless metallic iron dripping amount is the dimensionless metallic iron dripping amount when the boundary area S unit per unit iron-based raw material is 25 m 2 /ore-ton and the metallic iron dripping amount is 1.0. . Unit (-) means dimensionless.
圖5是表示通氣阻力指數KS、和鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit的關係的圖形。圖5的橫軸為鐵系原料與焦炭的每單位鐵系原料的邊界面積（m 2/礦石-噸），縱軸為通氣阻力指數KS（10 5℃/m）。 FIG. 5 is a graph showing the relationship between the ventilation resistance index KS and the boundary area S unit per unit iron-based raw material between the iron-based raw material and coke. The horizontal axis of Figure 5 is the boundary area per unit of iron-based raw materials and coke (m 2 /ore-ton), and the vertical axis is the ventilation resistance index KS (10 5 °C/m).
如圖4所示，於鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit成為25 m 2/礦石-噸以上時，確認到金屬鐵的滴落量增加。認為其原因在於：經還原而生成的金屬鐵與焦炭中的碳接觸的機會增加，金屬鐵被滲碳而金屬鐵的熔點降低。 As shown in FIG. 4 , when the boundary area S unit per unit iron-based raw material between the iron-based raw material and coke becomes 25 m 2 /ore-ton or more, it is confirmed that the amount of metallic iron dripping increases. The reason is considered to be that the metallic iron produced by reduction has an increased chance of coming into contact with the carbon in the coke, so that the metallic iron is carburized and the melting point of the metallic iron is lowered.
另外，如圖5所示，於鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit成為25 m 2/礦石-噸以上時，隨著金屬鐵的滴落量增加，通氣阻力指數KS降低至作為目標值的2000以下。通氣阻力指數KS的目標值2000為能夠繼續穩定的試驗的閾值。所謂穩定的試驗，是指填充層表面高度相對於時間而言均勻地降低，不會產生竄氣等故障的試驗。 In addition, as shown in Figure 5, when the boundary area S unit per unit iron-based raw material between the iron-based raw material and coke becomes 25 m 2 /ore-ton or more, the ventilation resistance index KS increases as the dripping amount of metallic iron increases. Reduced to below the target value of 2,000. The target value of 2000 for the ventilation resistance index KS is the threshold value at which a stable test can be continued. The so-called stable test refers to a test in which the surface height of the filling layer decreases uniformly with respect to time and does not cause problems such as blow-by.
根據該些結果，得知，藉由將鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit設為25 m 2/礦石-噸以上，可穩定地進行使風口前的爐內生成高濃度還原氣體的試驗。 From these results, it was found that by setting the boundary area S unit of the iron-based raw material and the coke per unit of the iron-based raw material to 25 m 2 /ore-ton or more, it is possible to stably increase the high temperature generated in the furnace in front of the tuyere. Test of reducing gas concentration.
本實施形態的高爐操作方法是基於所述試驗結果而成者，且為如下高爐操作方法，其中自高爐的爐頂裝入鐵系原料以及焦炭，並自高爐的風口吹入使風口前的爐內產生高濃度還原氣體的氣體，所述高爐操作方法將鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit設為規定範圍內。 The blast furnace operating method of this embodiment is based on the above test results, and is a blast furnace operating method in which iron-based raw materials and coke are charged from the top of the blast furnace and blown into the furnace from the tuyere of the blast furnace. A gas with a high concentration of reducing gas is generated in the blast furnace operating method so that the boundary area S unit per unit of the iron-based raw material and the coke is within a prescribed range.
此處，較佳為將鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit設為25 m 2/礦石-噸以上。藉此，可獲得充分的金屬鐵的滴落量，可實現高爐的穩定操作。另一方面，於鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit小於25 m 2/礦石-噸時，無法獲得充分的金屬鐵的滴落量，通氣阻力指數KS值變高。 Here, it is preferable to set the boundary area S unit per unit iron-based raw material between the iron-based raw material and coke to be 25 m 2 /ore-ton or more. Thereby, a sufficient dripping amount of metallic iron can be obtained, and stable operation of the blast furnace can be achieved. On the other hand, when the boundary area S unit per unit iron-based raw material and coke is less than 25 m 2 /ore-ton, a sufficient dripping amount of metallic iron cannot be obtained, and the ventilation resistance index KS value becomes high.
另外，邊界面積S unit是藉由增加爐內的每1層鐵系原料層中所混合的混合焦炭的質量W c、或減少爐內的每1層鐵系原料層的鐵系原料的質量W Iron而增加。通常，於高爐操作中，在增加爐內的每1層鐵系原料層中所混合的混合焦炭的質量W c時，為了使焦炭相對於鐵系原料的比率固定，而減少裝入至焦炭層的焦炭量，因此焦炭層薄層化。另一方面，於減少爐內的每1層鐵系原料層的鐵系原料的質量W Iron時，鐵系原料層薄層化。由於原料在高爐半徑方向上的下降速度未必固定，因此若焦炭層或鐵系原料層過度薄層化，則焦炭層或鐵系原料層的層結構有時會崩塌。因此，於將鐵系原料以及焦炭交替且呈層狀地裝入至高爐內，並使該些維持層狀在高爐內下降時，較佳為將邊界面積S unit設為53.1 m 2/礦石-噸以下。 In addition, the boundary area S unit is determined by increasing the mass W c of the mixed coke mixed in each iron-based raw material layer in the furnace, or decreasing the mass W of the iron-based raw material in each iron-based raw material layer in the furnace. Iron and increase. Normally, in a blast furnace operation, when increasing the mass W c of mixed coke mixed in each iron-based raw material layer in the furnace, in order to keep the ratio of coke to iron-based raw materials constant, the amount of water charged into the coke layer is reduced. The amount of coke results in a thinner coke layer. On the other hand, when the mass W Iron of the iron-based raw material per iron-based raw material layer in the furnace is reduced, the iron-based raw material layer becomes thinner. Since the falling speed of the raw material in the radial direction of the blast furnace is not necessarily constant, if the coke layer or the iron-based raw material layer becomes excessively thin, the layer structure of the coke layer or the iron-based raw material layer may collapse. Therefore, when the iron-based raw materials and coke are alternately charged into the blast furnace in layers, and the layers are maintained in the blast furnace while descending, it is preferable to set the boundary area S unit to 53.1 m 2 /ore- tons or less.
另外，高濃度還原氣體較佳為該高濃度還原氣體中的H 2氣體量（包含烴中的氫在內）為0 Nm 3/熔鐵-噸～500 Nm 3/熔鐵-噸的範圍內。藉此，可抑制爐內溫度的降低及還原反應速度的降低。另一方面，若高濃度還原氣體中的H 2氣體量超過500 Nm 3/熔鐵-噸，則爐內溫度降低，還原反應速度降低，因此欠佳。另外，於以單質的形式吹入H 2氣體的情況下，為了將風口前溫度保持為操作範圍內，較佳為於對H 2氣體進行加熱後予以送風。 In addition, the high-concentration reducing gas is preferably such that the amount of H 2 gas (including hydrogen in hydrocarbons) in the high-concentration reducing gas is in the range of 0 Nm 3 /ton of molten iron to 500 Nm 3 /ton of molten iron. . Thereby, it is possible to suppress a decrease in the temperature inside the furnace and a decrease in the reduction reaction rate. On the other hand, if the amount of H 2 gas in the high-concentration reducing gas exceeds 500 Nm 3 /molten iron-ton, the temperature in the furnace will decrease and the reduction reaction rate will decrease, which is undesirable. In addition, when H 2 gas is blown in as a simple substance, in order to maintain the temperature in front of the tuyere within the operating range, it is preferable to heat the H 2 gas and then blow it.
如以上所說明般，於本實施形態的高爐操作方法中，在實施使風口前的爐內產生高濃度還原氣體的高爐操作時，將自爐頂裝入的鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit設為規定範圍內。藉此，所生成的金屬鐵的滲碳得到促進，金屬鐵的熔點降低，並且恰當地保持高爐內的熔著帶及滴落帶中的金屬鐵的通液性，可將高爐內的氣體通氣性確保為能夠操作的範圍內，可實現高爐的穩定操作。 [實施例] As explained above, in the blast furnace operating method of this embodiment, when performing the blast furnace operation to generate a high-concentration reducing gas in the furnace before the tuyere, the iron-based raw materials and coke charged from the furnace top are mixed with each unit of iron. The boundary area S unit of the raw material is set within the specified range. Thereby, the carburization of the generated metallic iron is promoted, the melting point of the metallic iron is lowered, the liquid permeability of the metallic iron in the melting zone and the dripping zone in the blast furnace is properly maintained, and the gas in the blast furnace can be ventilated. The performance is ensured within the operable range to achieve stable operation of the blast furnace. [Example]
使用大型高爐實施如下高爐操作試驗，即，自爐頂交替裝入鐵系原料以及焦炭，使鐵系原料的質量以及焦炭原料的質量固定，使自爐頂裝入的鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit發生變化，並使風口前的爐內生成高濃度還原氣體。將操作條件及試驗結果示於下述表1中。 A large blast furnace was used to conduct a blast furnace operation test in which iron-based raw materials and coke were alternately charged from the top of the furnace, so that the mass of the iron-based raw materials and the mass of coke raw materials were fixed, and the iron-based raw materials and coke were charged from the top of the furnace. The boundary area S unit of the unit iron-based raw material changes, causing high-concentration reducing gas to be generated in the furnace in front of the tuyere. The operating conditions and test results are shown in Table 1 below.
[表1]
如表1所示般，確認到於將自爐頂裝入的鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit設為本發明的範圍的發明例1、發明例2中，金屬鐵的通液性及通氣性良好，能夠進行穩定操作。另一方面，於自爐頂裝入的鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit為本發明的範圍外的比較例1中，無法獲得充分的金屬鐵的通液性，通氣性亦不良。 As shown in Table 1, it was confirmed that in Invention Example 1 and Invention Example 2 in which the boundary area S unit per unit of the iron-based raw material and coke charged from the furnace top was within the range of the present invention, the metal Iron has good liquid permeability and air permeability, enabling stable operation. On the other hand, in Comparative Example 1 in which the boundary area S unit per unit of the iron-based raw material and coke charged from the furnace top was outside the range of the present invention, sufficient liquid permeability of metallic iron could not be obtained. Ventilation is also poor.
θ:傾斜角度θ:tilt angle
圖1是於H 2氣體-N 2氣體-CO氣體的三元系圖表的氣體成分組成中，以爐腹氣體組成表示藉由本實施形態的高爐操作方法使風口前的爐內生成的高濃度還原氣體的成分範圍的圖。 圖2是示意性地表示高爐內的鐵系原料層及焦炭層的形狀的圖。 圖3的（A）是示意性地表示鐵系原料層與混合裝入至鐵系原料層的焦炭粒子的圖，圖3的（B）是示意性地表示混合裝入至鐵系原料層的焦炭粒子的形狀的圖。 圖4是表示金屬鐵滴落量、和鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit的關係的圖形。 圖5是表示通氣阻力指數KS、和鐵系原料與焦炭的每單位鐵系原料的邊界面積S unit的關係的圖形。 Figure 1 shows the gas component composition in the ternary system diagram of H 2 gas-N 2 gas-CO gas, showing the furnace bosh gas composition to reduce the high concentration generated in the furnace before the tuyere by the blast furnace operating method of this embodiment. A diagram of the composition range of a gas. FIG. 2 is a diagram schematically showing the shapes of the iron-based raw material layer and the coke layer in the blast furnace. FIG. 3(A) is a diagram schematically showing an iron-based raw material layer and coke particles mixed and charged into the iron-based raw material layer. FIG. 3(B) is a diagram schematically showing a layer of coke particles mixed and charged into the iron-based raw material layer. Diagram of the shape of coke particles. FIG. 4 is a graph showing the relationship between the amount of metallic iron dripping and the boundary area S unit per unit of iron-based raw material between the iron-based raw material and coke. FIG. 5 is a graph showing the relationship between the ventilation resistance index KS and the boundary area S unit per unit iron-based raw material between the iron-based raw material and coke.
Claims (7)
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| JP2022064978 | 2022-04-11 | ||
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| JPS60228610A (en) * | 1984-04-26 | 1985-11-13 | Nippon Kokan Kk <Nkk> | Method for operating blast furnace |
| JPS63161104A (en) * | 1986-12-23 | 1988-07-04 | Kawasaki Steel Corp | Method for charging raw material into vertical type furnace |
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