JPH03177513A - Smelting reduction method for metal and smelting reduction furnace - Google Patents
Smelting reduction method for metal and smelting reduction furnaceInfo
- Publication number
- JPH03177513A JPH03177513A JP33326289A JP33326289A JPH03177513A JP H03177513 A JPH03177513 A JP H03177513A JP 33326289 A JP33326289 A JP 33326289A JP 33326289 A JP33326289 A JP 33326289A JP H03177513 A JPH03177513 A JP H03177513A
- Authority
- JP
- Japan
- Prior art keywords
- furnace
- gas
- coal
- smelting reduction
- ore
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000009467 reduction Effects 0.000 title claims abstract description 153
- 238000003723 Smelting Methods 0.000 title claims abstract description 82
- 238000000034 method Methods 0.000 title claims abstract description 56
- 229910052751 metal Inorganic materials 0.000 title claims description 35
- 239000002184 metal Substances 0.000 title claims description 35
- 239000007789 gas Substances 0.000 claims abstract description 237
- 239000003245 coal Substances 0.000 claims abstract description 190
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 55
- 238000007664 blowing Methods 0.000 claims abstract description 47
- 229910052742 iron Inorganic materials 0.000 claims abstract description 25
- 239000002994 raw material Substances 0.000 claims abstract description 20
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000001301 oxygen Substances 0.000 claims abstract description 15
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 15
- 239000011449 brick Substances 0.000 claims description 35
- 239000002245 particle Substances 0.000 claims description 30
- 238000001816 cooling Methods 0.000 claims description 14
- 238000002844 melting Methods 0.000 claims description 7
- 230000008018 melting Effects 0.000 claims description 7
- 239000002826 coolant Substances 0.000 claims description 6
- 230000007246 mechanism Effects 0.000 claims description 4
- 230000000630 rising effect Effects 0.000 claims description 2
- 150000002739 metals Chemical class 0.000 claims 2
- 238000002485 combustion reaction Methods 0.000 abstract description 73
- 230000001174 ascending effect Effects 0.000 abstract 2
- 238000006722 reduction reaction Methods 0.000 description 142
- 238000002407 reforming Methods 0.000 description 27
- 238000000197 pyrolysis Methods 0.000 description 25
- 230000003647 oxidation Effects 0.000 description 22
- 238000007254 oxidation reaction Methods 0.000 description 22
- 238000006243 chemical reaction Methods 0.000 description 17
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 16
- 238000002347 injection Methods 0.000 description 15
- 239000007924 injection Substances 0.000 description 15
- 239000002893 slag Substances 0.000 description 15
- 230000000694 effects Effects 0.000 description 14
- 238000012546 transfer Methods 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 12
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 10
- 239000011819 refractory material Substances 0.000 description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- 239000003575 carbonaceous material Substances 0.000 description 9
- 239000000843 powder Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 8
- 229910002092 carbon dioxide Inorganic materials 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 239000000571 coke Substances 0.000 description 7
- 238000007796 conventional method Methods 0.000 description 6
- 239000000428 dust Substances 0.000 description 6
- 229930195733 hydrocarbon Natural products 0.000 description 6
- 150000002430 hydrocarbons Chemical class 0.000 description 6
- 235000013980 iron oxide Nutrition 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- 230000001590 oxidative effect Effects 0.000 description 5
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 4
- 239000001569 carbon dioxide Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- 238000006114 decarboxylation reaction Methods 0.000 description 3
- 229910001873 dinitrogen Inorganic materials 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 230000008439 repair process Effects 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 2
- 229910001021 Ferroalloy Inorganic materials 0.000 description 2
- 235000019738 Limestone Nutrition 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- 235000012255 calcium oxide Nutrition 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000002309 gasification Methods 0.000 description 2
- 229910052595 hematite Inorganic materials 0.000 description 2
- 239000011019 hematite Substances 0.000 description 2
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 2
- 239000006028 limestone Substances 0.000 description 2
- 238000011017 operating method Methods 0.000 description 2
- 230000036284 oxygen consumption Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000006057 reforming reaction Methods 0.000 description 2
- 238000003303 reheating Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000002678 semianthracite Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 101100243025 Arabidopsis thaliana PCO2 gene Proteins 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- 102100021102 Hyaluronidase PH-20 Human genes 0.000 description 1
- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 101150055528 SPAM1 gene Proteins 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 229910002090 carbon oxide Inorganic materials 0.000 description 1
- 239000003610 charcoal Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 239000003034 coal gas Substances 0.000 description 1
- 239000000112 cooling gas Substances 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 239000010459 dolomite Substances 0.000 description 1
- 229910000514 dolomite Inorganic materials 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000005188 flotation Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000004313 glare Effects 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 230000009291 secondary effect Effects 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Landscapes
- Manufacture Of Iron (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は金属酸化物の溶融還元法に関し、特に鉄、合金
鉄の溶融還元法に係わるものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for melting and reducing metal oxides, and particularly to a method for melting and reducing iron and iron alloys.
（従来の技術）
溶融還元法においては、炉内で多量に消費される熱量を
効率的かつ安価に供給するために、二次燃焼の比率を向
上させ、石炭単位量あたりの発り＾量を増加させる試み
が多くなされている。つまり、炭素を一酸化炭素まで酸
化する時に発生する熱量は、約２２００ｋｃａｉ） ／
ｋｇ −Ｃであるのに対して、二酸化炭素まで酸化する
時に発生する熱量は、約７８００ｋｃａｊＪ ／ｋｇ
−Ｃであるため、炭素眩あたり、酸素Ｎｍ３あたりの発
生熱量が大きいことが理由である。また、水素は、二次
燃焼でしか燃焼しないため、水素の燃焼熱を有効利用す
るためには、二次燃焼が不可欠である。(Conventional technology) In the smelting reduction method, in order to efficiently and inexpensively supply the large amount of heat consumed in the furnace, the ratio of secondary combustion is improved and the amount of emissions per unit amount of coal is reduced. Many attempts have been made to increase it. In other words, the amount of heat generated when carbon is oxidized to carbon monoxide is approximately 2200 kcai) /
kg -C, whereas the amount of heat generated when oxidizing to carbon dioxide is approximately 7800 kcajJ / kg
-C, the amount of heat generated per carbon glare and per oxygen Nm3 is large. Furthermore, since hydrogen is combusted only through secondary combustion, secondary combustion is essential in order to effectively utilize the combustion heat of hydrogen.
例えば、特開昭６２−２８０３１１号公報に見られるよ
うに、溶融還元炉において高い二次燃焼率を得てこの燃
焼熱を効率よく鉄浴に伝達することにより、石炭の発生
熱量を高めかつ熱効率を高めることを目的とした操業法
がある。For example, as seen in Japanese Patent Application Laid-Open No. 62-280311, by obtaining a high secondary combustion rate in a smelting reduction furnace and efficiently transmitting this combustion heat to the iron bath, the amount of heat generated from coal is increased and the thermal efficiency is increased. There are operating methods aimed at increasing the
しかし、溶融還元炉での二次燃焼率を高めたとしても、
燃料として揮発分（以下ＶＭという）が２５〜４０％と
高い一般炭を直接に炉に使用した場合は、二次燃焼率の
実用的な限界値は、４０〜５０％程度である。なぜなら
ば、ＶＭを多量に含む一般炭は、溶融還元炉内では燃焼
特性が悪く、高二次燃焼率操業を実施すると、着熱効率
が悪化することが一般に認められている。However, even if the secondary combustion rate in the smelting reduction furnace is increased,
When steam coal with a high volatile content (hereinafter referred to as VM) of 25 to 40% is used directly in the furnace as fuel, the practical limit value of the secondary combustion rate is about 40 to 50%. This is because steam coal containing a large amount of VM has poor combustion characteristics in a smelting reduction furnace, and it is generally recognized that heat transfer efficiency deteriorates when high secondary combustion rate operation is performed.
このように一般炭では高二次燃焼の操業において、急激
に着熱効率が悪化することから、一般炭を使用して溶融
還元炉で二次燃焼率を上げた場合は、炉内のスラグ上の
空間での単位体積あたりの発生熱量が増加して、ガスの
温度が急激に上昇することが操業上の問題点としてあげ
られる。In this way, heat transfer efficiency deteriorates rapidly with steam coal during high secondary combustion operations, so when steam coal is used to increase the secondary combustion rate in a smelting reduction furnace, the space above the slag in the furnace An operational problem is that the amount of heat generated per unit volume increases, causing the temperature of the gas to rise rapidly.
例えば、二次燃焼率が５０％の場合に、この二次燃焼の
着熱効率がたとえ８０％と比較的良好な操業が行えた場
合でも、炉上部のガス温度は１９００℃以上となり、炉
の上部の煉瓦の耐用温度をはるかに超えた温度となって
しまい、安価に金属を製造する方法とは言えない。For example, when the secondary combustion rate is 50%, even if the heat transfer efficiency of this secondary combustion is 80% and relatively good operation is possible, the gas temperature in the upper part of the furnace will exceed 1900°C, and the upper part of the furnace will The temperature far exceeds the withstand temperature of bricks, so it cannot be said to be an inexpensive method of manufacturing metal.
つまり、一般に鉄や合金鉄を経済的に製造するためには
煉瓦の費用は数百円／Ｔから、数千円／Ｔ程度に抑える
ことが必須であり、この価格に引き合う耐火物の材質と
しては、酸化マグネシウム、焼成ドロマイト質、酸化ア
ルミニウム、酸化珪素および酸化クロム等の比較的に安
価な材質の煉瓦を用いることが不可欠の条件となる。In other words, in general, in order to economically produce iron and ferroalloys, it is essential to keep the cost of bricks from a few hundred yen/T to several thousand yen/T. It is essential to use bricks made of relatively inexpensive materials such as magnesium oxide, calcined dolomite, aluminum oxide, silicon oxide, and chromium oxide.
しかし、これらの材質では、製鉄や合金鉄の製造の条件
では、耐用温度は１７００〜１８００℃でしかなく、溶
融還元においては、製造費用の増加が大きな問題となる
。However, these materials can only withstand temperatures of 1,700 to 1,800° C. under the conditions of iron manufacturing and ferroalloy manufacturing, and an increase in manufacturing costs becomes a major problem in smelting reduction.
つまり、溶融還元炉で二次燃焼率が４０〜５０％以上の
高二次燃焼率操業における問題点としては、高温でかつ
酸化力の強いガスによる炉壁耐大物の損耗速度が大きい
という点である。In other words, the problem with high secondary combustion rate operation in smelting reduction furnaces where the secondary combustion rate is 40 to 50% or more is that the high temperature and strong oxidizing gas causes a high rate of wear and tear on the large parts of the furnace wall. .
一般炭使用の操業では二次燃焼率的５０％では、二次燃
焼の着熱効率が８５％程度の着熱効率の操業でしかない
ことから、炉上部空間のガス温度が１８００〜２０００
℃となり、かつ、グラファイトを含む耐火物への劣化効
果の大きい酸化性ガスであるＨ２ＯとＣＯ２の比率の高
いガスが溶融還元炉から発生する結果、高二次燃焼率の
操業では炉上部の煉瓦損耗は激しい。In operations using steam coal, if the secondary combustion rate is 50%, the heat transfer efficiency of the secondary combustion is only about 85%, so the gas temperature in the upper space of the furnace is 1800 to 2000.
℃ and has a high ratio of H2O and CO2, which are oxidizing gases that have a large deteriorating effect on refractories including graphite, generated from the smelting reduction furnace. As a result, during operation with a high secondary combustion rate, the bricks in the upper part of the furnace are worn out. is intense.
一般に耐火物の損耗速度を低減するためには、いくつか
の操業的な要因があるが、耐火物の稼働面の温度を低下
させることが最も効果的な方法である。また、ガスに触
れる部分の耐火物は酸化力の強いガスに曝された場合も
損耗速度が増加することが認められており、ガスの酸化
度を低減することも耐火物保護のために効果的な方法で
ある。Generally, there are several operational factors to reduce the wear rate of refractories, but the most effective method is to lower the temperature of the working surface of the refractories. In addition, it is recognized that the rate of wear and tear of refractories in parts that come into contact with gas increases when exposed to gases with strong oxidizing power, and reducing the degree of oxidation of gas is also effective for protecting refractories. This is a great method.
しかしながら、ガス温度を下げて、かつ、ガスの酸化度
を低下させることは、二次燃焼率を増やして、鉄浴に多
量の熱を供給して、石炭原単位を低減することと矛盾す
ることとなり、従来広では、石炭原単位が少なく、耐火
物の寿命も長い操業ということは困難であった。However, lowering the gas temperature and the degree of oxidation of the gas is inconsistent with increasing the secondary combustion rate, supplying a large amount of heat to the iron bath, and reducing the coal consumption rate. Therefore, in the past, it was difficult to operate with low coal consumption and long life of refractories.
従って、煉瓦の耐用を考慮すると溶融還元法の二次燃焼
率は前述の４０％程度にしか高めることはできなく、つ
まり、低二次燃焼で操業する結果、鉄の溶融還元の場合
は、もしも鉱石を予備還元なく使用する場合は、石炭原
単位も１０００〜１２００ｋｇ／Ｔと多くなってしまい
、経済的な溶銑の製造方法はできなかった。Therefore, considering the durability of the bricks, the secondary combustion rate of the smelting reduction method can only be increased to about 40%, as mentioned above.In other words, as a result of operating at a low secondary combustion When ore is used without preliminary reduction, the coal consumption rate also increases to 1000 to 1200 kg/T, making it impossible to create an economical method for producing hot metal.
一方、石炭原単位を低減するためには、原料の鉱石を予
備還元することは効果的な方法の一つである。つまり、
溶銑の製造に用いる鉄鉱石は主として、ヘマタイト鉱石
（Ｆｅ２０３）もしくはマグネタイト鉱石（Ｆｅ３０４
）であり、これらの酸化鉄の還元のためにＣを消費する
ことと、還元熱が膨大であることにより、石炭原単位を
低減できない問題があった。On the other hand, in order to reduce the coal consumption rate, one effective method is to pre-reduce raw material ore. In other words,
The iron ore used for producing hot metal is mainly hematite ore (Fe203) or magnetite ore (Fe304).
), and there was a problem in that the coal consumption rate could not be reduced due to the consumption of C for the reduction of these iron oxides and the enormous amount of reduction heat.
しかし、鉱石を予備還元することにより、酸化鉄中の酸
素量を低減し、還元により消費される炭素量が低減でき
るとともに、酸化鉄の還元の際に必要とされる還元熱が
低減されるため、石炭の燃焼熱も低減できる。これらの
理由から鉱石の予備還元は石炭原単位の低減方法として
非常に有効な方法である。However, by pre-reducing the ore, the amount of oxygen in the iron oxide can be reduced, and the amount of carbon consumed by reduction can be reduced, as well as the reduction heat required when reducing the iron oxide. , the combustion heat of coal can also be reduced. For these reasons, preliminary reduction of ore is a very effective method for reducing coal consumption.
また、溶融還元炉から発生するガスは、Ｎ２０゜ＨＣｏ
、Ｃｏ２．Ｎ２から構成されており、２ ′
鉄の溶融還元法では鉄鉱石の予備還元を実施する方法と
しては、このガスを有効利用することが最も望ましいこ
とは明らかであり、種々方法が提案されている。In addition, the gas generated from the melting reduction furnace is N20°HCo
, Co2. It is clear that effective use of this gas is the most desirable method for preliminary reduction of iron ore in the 2' iron smelting reduction method, and various methods have been proposed. .
効率的な鉱石の予備還元の一つの方法として、ガスを冷
却することにより鉱石の還元を阻害するＮ２０を水とし
て除去した後、これもまた、還元を阻害するＣＯ２の比
率を低減する目的で、ガスを脱炭酸して予備還元炉での
還元効率を高める方法もある。As one method of efficient ore pre-reduction, after removing N20, which inhibits ore reduction, as water by cooling the gas, it is also possible to reduce the proportion of CO2, which inhibits reduction. Another method is to decarboxylate the gas to increase the reduction efficiency in the pre-reduction furnace.
しかし、脱水、脱炭酸を実施するためには、ガスは常温
まで冷却されなければならず、このガスを予備還元に必
要な温度である８００〜ｔｏ００℃に再加熱して鉱石を
予備還元することが必要である。However, in order to perform dehydration and decarboxylation, the gas must be cooled to room temperature, and this gas must be reheated to 800 to 00°C, the temperature required for preliminary reduction, to pre-reduce the ore. is necessary.
この方法においては、溶融還元炉の二次燃焼率に係わら
ず予備還元のガス酸化度（（Ｐｃｏ２＋ＰＨ２０）／（
ＰＣＯ２＋ＰＣＯ＋ＰＨ２＋ＰＩＩ２０））を鉱石の還
元に適正な比率まで低減でき、鉱石還元の化学平衡およ
び反応速度を向上することができることから、溶融還元
炉に望ましい還元率を得ることができる。In this method, the gas oxidation degree ((Pco2+PH20)/(
PCO2 + PCO + PH2 + PII20)) can be reduced to an appropriate ratio for ore reduction, and the chemical equilibrium and reaction rate of ore reduction can be improved, making it possible to obtain a desirable reduction rate for the smelting reduction furnace.
しかしながら、この方法では、溶融還元炉から発生した
ガスを冷却する排熱ボイラー、集塵設備、除水設備、脱
炭酸設備、需給変動防止のためのガスホルダー、ガスの
昇圧機およびガス加熱用の熱交換設備等の膨大な設備費
が必要となり、経済的な予備還元法とは言い難い。However, this method requires a waste heat boiler to cool the gas generated from the smelting reduction furnace, dust collection equipment, water removal equipment, decarbonation equipment, a gas holder to prevent fluctuations in supply and demand, a gas booster, and a gas heating equipment. This method requires a huge amount of equipment costs such as heat exchange equipment, and cannot be called an economical preliminary reduction method.
また一方では、このような膨大な設備を用いずに、設備
費を低減することを目的として、溶融還元炉から発生す
るガスを常温まで冷却せず、予備還元に適当な温度まで
の冷却に止め、ガスを直接予備還元炉に導き、鉱石を予
備還元する方法もある。この方法では、ガス処理設備と
して発生ガスの回収ダクトと除塵機程度の簡単な設備で
済み、設備費が低減される効果がある。On the other hand, with the aim of reducing equipment costs without using such huge equipment, the gas generated from the smelting reduction furnace is not cooled to room temperature, but is only cooled to a temperature suitable for preliminary reduction. There is also a method to lead the gas directly to the pre-reduction furnace and pre-reduce the ore. This method requires simple equipment such as a recovery duct for generated gas and a dust remover as gas processing equipment, and has the effect of reducing equipment costs.
しかし、一方では、この方法では溶融還元炉から発生す
るガスの酸化度は、溶融還元炉の二次燃焼率で決まって
しまい、酸化度を低めることができない問題が存在する
。However, on the other hand, in this method, the degree of oxidation of the gas generated from the smelting reduction furnace is determined by the secondary combustion rate of the smelting reduction furnace, and there is a problem that the oxidation degree cannot be lowered.
この方法においては、溶融還元炉で二次燃焼率が低い操
業、つま、す、２０〜３０％程度の操業であれば、予備
還元温度８００〜１０００℃の化学平衡から予想される
ように、鉄鉱石（Ｆｅ２０３）は、一部は金属鉄まで還
元され、鉱石の予備還元率として約４０％が可能である
。In this method, if the smelting reduction furnace is operated with a low secondary combustion rate of about 20 to 30%, the iron ore A portion of the stone (Fe203) is reduced to metallic iron, and a preliminary reduction rate of about 40% is possible for the ore.
しかしながら、予備還元率が約４０％で溶融還元炉の二
次燃焼率が約２０％では、操業に必要な石炭原単位は、
１１００ｋｇ／Ｔ以上となり、コークス炉高炉法の石炭
原単位の７００〜８００ｋｇ／ Ｔよりも大幅に多い操
業となり、この方法でも経済的に溶銑を製造することは
できない。However, when the preliminary reduction rate is about 40% and the secondary combustion rate of the smelting reduction furnace is about 20%, the coal consumption rate required for operation is:
The amount is 1,100 kg/T or more, which is significantly higher than the 700 to 800 kg/T of coal consumption in the coke oven blast furnace method, and hot metal cannot be produced economically even with this method.
さて、一方で、溶融還元炉での二次燃焼率を高めて、鉄
浴への石炭単位重量当たりの熱供給量を増加させて、石
炭原単位を低減する操業法では、溶融還元炉の熱供給は
改善される。しかしながら、４０〜５０％程度の高二次
燃焼により得られた溶融還元の発生ガスのガス酸化度で
は、このガスを除水や脱炭酸なしで直接予備還元に用い
た場合は、鉄鉱石を十分に予備還元することはできない
。On the other hand, in an operation method that reduces the coal consumption rate by increasing the secondary combustion rate in the smelting reduction furnace and increasing the amount of heat supplied per unit weight of coal to the iron bath, Supply will be improved. However, with the gas oxidation degree of the gas generated by smelting reduction obtained by high secondary combustion of about 40 to 50%, if this gas is used for direct preliminary reduction without water removal or decarboxylation, iron ore cannot be sufficiently removed. Preliminary refunds are not possible.
なぜならば、このような酸化度のガスを用いた場合、予
備還元炉で通常用いられる還元温度である８００〜１０
００℃においては、化学平衡的にＦｅ５０．までしか還
元できない。つまり、通常の鉄鉱石であるヘマタイト鉱
石（Ｆｅ２０３）では、予備還元率は約ｎ％までであり
、砂鉄等のマグネタイト鉱石（Ｆｅ３０４）ではまった
く還元できない結果となる。つまり、二次燃焼後のガス
組成できまる化学平衡に支配されてしまい、予備還元炉
での鉱石の還元到達が制限されてしまうため、高い予備
還元率が得られない欠点がある。This is because when using a gas with such an oxidation degree, the reduction temperature normally used in a preliminary reduction furnace is 800 to 10.
At 00°C, Fe50. It can only be returned up to. That is, with hematite ore (Fe203), which is a normal iron ore, the preliminary reduction rate is up to about n%, and with magnetite ore (Fe304) such as iron sand, the result is that it cannot be reduced at all. In other words, it is dominated by the chemical equilibrium determined by the gas composition after secondary combustion, and the reduction of the ore in the pre-reduction furnace is limited, so there is a drawback that a high pre-reduction rate cannot be obtained.
したがって、一般炭を直接使用する溶融還元炉では、二
次燃焼率を４０〜５０％まで向上しても鉄鉱石の予備還
元率が低位のまま留まることから、十分に石炭原単位を
低減できず、この方法でも石炭原単位は９００ｋｇ／Ｔ
程度にしかならない。Therefore, in a smelting reduction furnace that directly uses steam coal, even if the secondary combustion rate is improved to 40-50%, the preliminary reduction rate of iron ore remains low, making it impossible to sufficiently reduce the coal consumption rate. Even with this method, the coal consumption rate is 900kg/T.
It will only be to a certain extent.
ところで、先に述べたように、溶融還元炉での二次燃焼
率は、使用する炭材の平均の揮発分含有率に強く影響さ
れることも判明している。By the way, as mentioned above, it has also been found that the secondary combustion rate in the smelting reduction furnace is strongly influenced by the average volatile content of the carbon material used.
安価でかつ産出量も多い一般炭は、通常はＶＭを２５〜
４０％含んでいる。一般炭を使用して安価に溶銑を製造
しようとする場合、一般炭をそのまま溶融還元炉で使用
すると、熱効率が比較的高い状態で到達できる二次燃焼
率は４０〜５０％であり、鉄鉱石の溶融還元に必要な熱
を供給するためには、さらに二次燃焼率と着熱効率を同
時に高めることにより、石炭原単位を低減することも必
要となる。Thermal coal, which is cheap and produced in large quantities, usually has a VM of 25~
Contains 40%. When trying to produce hot metal cheaply using steam coal, if steam coal is used as is in a smelting reduction furnace, the secondary combustion rate that can be achieved with relatively high thermal efficiency is 40 to 50%, and iron ore In order to supply the heat necessary for smelting and reduction, it is also necessary to reduce the coal consumption rate by simultaneously increasing the secondary combustion rate and heat transfer efficiency.
このための−法として石炭を部分的に乾溜してＶＭの含
有率を低下させる方法もある。しかし、通常の石炭乾溜
法では特別の石炭の乾溜炉が必要となり、また、乾溜の
ために熱量が必要であり、このために増分の設備費がか
かる。As a method for this purpose, there is also a method of partially dry distilling the coal to reduce the VM content. However, conventional coal dry distillation methods require special coal dry distillation furnaces and require additional heat for dry distillation, which incurs incremental equipment costs.
したがって、特別の乾溜炉を用いずに、また、乾溜熱も
経済的に調達できる方法の考案がなければ、石炭を乾溜
する方法を経済的に部分的に乾溜した石炭を溶融還元炉
に使用して、溶銑を製造することはできない。Therefore, without using a special dry distillation furnace, and without devising a method that can economically procure dry distillation heat, it is economically possible to use partially dry distilled coal in a smelting reduction furnace. Therefore, it is not possible to produce hot metal.
つまり、石炭の乾溜と溶融還元炉から発生するガスの酸
化度の低減が同時にでき、かつ、経済的な石炭の乾溜お
よびガスの改質の方法で、変動コスト、設備費の増分な
しに石炭原単位が低減できる技術が望まれていた。In other words, it is an economical method for dry distilling coal and reducing the degree of oxidation of the gas generated from the smelting reduction furnace at the same time, without increasing variable costs or equipment costs. A technology that could reduce the number of units was desired.
言い換えれば、経済的に溶銑を製造するためには、簡易
かつ安価な設備で、溶融還元炉からの発生ガスの酸化を
低下させるとともに、石炭の一部を乾溜することができ
る方法が必要となる。In other words, in order to produce hot metal economically, a method is needed that can reduce the oxidation of the gas generated from the smelting reduction furnace and dry distill a portion of the coal using simple and inexpensive equipment. .
また、石炭の採鉱は（００万〜５００万Ｔ／年程度の多
量に行われることから、石炭の輸送による一部の粉化や
選炭による粉の増加等の要因が重なって、製鉄所に荷揚
げされる際には、約ｌＯ〜２０％が２ｍ１１以下の粉の
状態となっている。In addition, since coal mining is carried out in large quantities (approximately 5 million to 5 million tons per year), factors such as some pulverization during coal transportation and an increase in the amount of powder during coal preparation occur, resulting in unloading at steel mills. When used, approximately 10 to 20% of the powder is in the form of powder of 2 ml or less.
この粉炭を有効に利用することができなければ、余剰の
石炭の処分をしなければならず、処分のための設備や費
用が発生することの問題点もある。If this pulverized coal cannot be used effectively, surplus coal must be disposed of, which poses a problem in that disposal equipment and costs are incurred.
したがって、経済的に溶銑を製造するためには、この粉
炭を有効利用することが重要であるが、粉炭を溶融還元
炉に上方から投入する際に、溶融還元炉から発生するガ
スの上昇流により、粉炭の一部が飛散してしまい、有効
利用できない問題点があった。Therefore, in order to economically produce hot metal, it is important to make effective use of this powdered coal. However, there was a problem in that some of the powdered coal was scattered and could not be used effectively.
石炭乾溜とガス改質（ガスの酸化度の低減法）としては
、例えば、溶融還元炉もしくは、石炭のガス化炉の発生
ガスを利用してコークスをガス化する方法について、特
開昭８２−２８３１９０号公報に示されるような技術が
あるが、この方法ではガス化に用いる炭材としては、通
気性の良い塊状のコークスしか用いることはできない。As for dry distillation of coal and gas reforming (a method for reducing the degree of oxidation of gas), for example, a method of gasifying coke using gas generated from a smelting reduction furnace or a coal gasification furnace is described in Japanese Patent Laid-Open No. 1982- There is a technique as shown in Japanese Patent No. 283190, but in this method, only lump coke with good air permeability can be used as the carbon material used for gasification.
つまり、このような方法においてＶＭを含む石炭を使用
した場合は、乾溜時にタールが発生してガスが低温に成
った部分でタールが戒化し、ガスの通気を阻害する問題
がある。したがって、この方法では、粉の混在する石炭
を乾溜することは困難である。That is, when coal containing VM is used in such a method, there is a problem in that tar is generated during dry distillation, and the tar condenses in the areas where the gas is at a low temperature, impeding the ventilation of the gas. Therefore, with this method, it is difficult to dry distill coal containing powder.
一方、粉鉱石は塊鉱石に比べて採鉱が容易であり、また
水洗や浮遊選と言った手段により品質を高めることが可
能であることが知られている。而してこの粉鉱石を上手
に利用することは安価に銑鉄を製造するために重要であ
る。On the other hand, it is known that fine ore is easier to mine than lump ore, and that its quality can be improved by means such as washing and flotation. Therefore, it is important to make good use of this fine ore in order to produce pig iron at low cost.
また粉鉱石を煉瓦の冷却等に使用できれば余分の物質を
炉内に供給する増分コストが無く、熱的に不利も少ない
。同様のことが粉状の生石灰等の副原料にも適用できる
。Moreover, if the fine ore can be used for cooling bricks, etc., there is no additional cost of supplying extra material into the furnace, and there is little thermal disadvantage. The same thing can be applied to auxiliary raw materials such as powdered quicklime.
（発明が解決しようとする課題）
本発明においては、かかる問題を解決して、設備を簡略
にして、かつ、予備還元炉での鉄鉱石の還元効率を高め
るとともに、溶融還元炉での二次燃焼率も高めることに
より、溶融還元法における石炭原１４位を低減し、また
耐火物の寿命も長く設備費が安価であり、かつ製造原価
も安価な溶銑製造を行う技術を提供するものである。(Problems to be Solved by the Invention) The present invention solves these problems, simplifies the equipment, increases the reduction efficiency of iron ore in the preliminary reduction furnace, and By increasing the combustion rate, it reduces the number of coal sources in the smelting reduction method, and also provides a technology for producing hot metal that has a long life for refractories, low equipment costs, and low production costs. .
（課題を解決するための手段）
本発明においては、溶融還元に使用される粉状の原料を
炉上部の燃焼ガス空間に吹込み、この原料の顕熱及び反
応の吸熱によりガス温度を低下させる。特に必然的に発
生する粉状の石炭を炉上部の燃焼ガス空間に吹込み、こ
の石炭を乾溜し、乾溜される際に発生する炭化水素系の
ガスと溶融還元炉から発生するＨＯとＣＯ２を多量に含
む高温ガスを反応させる。即ち、ガスの酸化度を下げ、
かつ反応熱（吸熱反応）によりガス温度を低下させる。(Means for Solving the Problems) In the present invention, a powdered raw material used for smelting reduction is blown into the combustion gas space in the upper part of the furnace, and the gas temperature is lowered by the sensible heat of the raw material and the endotherm of the reaction. . In particular, the powdered coal that is inevitably generated is blown into the combustion gas space in the upper part of the furnace, and this coal is dry distilled, and the hydrocarbon gas generated during dry distillation and the HO and CO2 generated from the smelting reduction furnace are removed. Reacts with a large amount of high-temperature gas. In other words, the degree of oxidation of the gas is lowered,
In addition, the gas temperature is lowered by the heat of reaction (endothermic reaction).
従って煉瓦の耐用寿命を延長し、かつ低酸化度のガスに
よる効率的な予備還元が実施できる。又乾瑠された石炭
を溶融還元炉に供給することにより、二次燃焼率の高い
操業を実施し、安価な溶銑を製造する。さらに又粉状の
原料として粉鉱石を用いる場合には、この粉鉱石が炉内
の高温ガスと接触して予熱され、部分的には予備還元も
される。Therefore, the service life of the bricks can be extended, and efficient preliminary reduction can be carried out using a gas with a low oxidation degree. Furthermore, by supplying the dry-roasted coal to the smelting reduction furnace, an operation with a high secondary combustion rate is carried out and cheap hot metal is produced. Furthermore, when fine ore is used as a powdered raw material, this fine ore is brought into contact with the high temperature gas in the furnace to be preheated and partially pre-reduced.
以下本発明を詳述する。The present invention will be explained in detail below.
溶融還元炉の操業においては、第１図の炉体１に耐火煉
瓦の内張り８をされた炉の下部に、溶銑１３とスラグ１
４がそれぞれ浴を形成している。この溶銑およびスラグ
は、１４００〜１７００℃程度の高温であり、この中に
鉱石を供給して、酸化鉄を溶融した後に、スラグ内の混
在しているコークスもしくはチャーの形態をしている炭
材および溶銑中の溶存炭素がこの溶融酸化鉄を還元して
、溶銑が製造される。In the operation of a smelting reduction furnace, hot metal 13 and slag 1 are placed in the lower part of the furnace body 1 shown in FIG. 1 lined with refractory bricks 8.
4 each form a bath. This hot metal and slag have a high temperature of about 1,400 to 1,700 degrees Celsius, and after ore is fed into this and iron oxide is melted, carbonaceous material in the form of coke or char mixed in the slag is extracted. Dissolved carbon in the hot metal reduces this molten iron oxide to produce hot metal.
鉱石の供給方法としては、炉の上部のホッパーから落下
投入する方法、炉の側壁から吹付ける方法、およびスラ
グもしくは溶銑中に吹込む方法等があるが、第１図には
、代表例として炉上方のホッパー５から鉱石を供給する
方法を記述した。There are several ways to supply ore, such as dropping it from a hopper at the top of the furnace, blowing it from the side wall of the furnace, and blowing it into slag or hot metal. A method for supplying ore from the upper hopper 5 has been described.
還元熱および生成物の顕熱を補うために炉内の溶銑およ
びスラグ内の炭材に上吹ランス２から酸素（また、これ
は酸素富化空気、もしくは加熱空気でも良い）が供給さ
れる。供給された酸素は、石炭および溶銑内の溶存炭素
を燃焼して熱を発生する。また、これらのガスとも燃焼
反応を起こし、さらに熱を発生する。前者の燃焼を一次
燃焼、後者の燃焼を二次燃焼と称する。Oxygen (this may also be oxygen-enriched air or heated air) is supplied from the top blowing lance 2 to the hot metal in the furnace and the carbonaceous material in the slag in order to supplement the heat of reduction and the sensible heat of the product. The supplied oxygen burns dissolved carbon in the coal and hot metal to generate heat. In addition, combustion reactions occur with these gases, further generating heat. The former combustion is called primary combustion, and the latter combustion is called secondary combustion.
また、鉱石の溶解、還元反応および熱移動の促進を目的
として、炉の底から羽口３を通して撹拌のためにガスを
供給する。このガスは撹拌を目的としていることから、
ガス種は特に限定されるものでなく、一般には、窒素、
アルゴン、酸素、プロパン等の炭化水素が用いられる。In addition, gas is supplied from the bottom of the furnace through the tuyere 3 for stirring in order to promote melting of the ore, reduction reaction, and heat transfer. Since this gas is intended for stirring,
The type of gas is not particularly limited, and in general, nitrogen,
Hydrocarbons such as argon, oxygen and propane are used.
石炭の供給は、溶融還元炉内の炭素バランスをほぼ一定
に保つように供給される。供給方法としては、鉱石と同
様の方法があり、第１図には、代表例として炉上方のホ
ッパー４から石炭を供給する方法を記述した。The coal supply is such that the carbon balance within the smelting reduction furnace is maintained approximately constant. As a feeding method, there are methods similar to those for ore, and FIG. 1 shows a method of feeding coal from a hopper 4 above the furnace as a typical example.
溶融還元の操業中には、鉱石はホッパー５から、また石
炭はホッパー４から連続的に供給され、酸素も上吹きの
ランス２からスラグおよび溶銑の方向に吹付けられ、供
給された鉱石は溶解、還元され、溶銑として炉下部の溶
銑浴に沈降する。During the smelting reduction operation, ore is continuously supplied from hopper 5 and coal from hopper 4, and oxygen is also blown from top-blowing lance 2 in the direction of the slag and hot metal, so that the supplied ore is melted. , is reduced and settles as hot metal in the hot metal bath at the bottom of the furnace.
また、石炭が燃焼したガスは、排ガスダクト１２を経由
して回収されて、ガス中のダストは集塵機って除塵され
、予備還元炉１０で鉱石の予備還元の還元ガス、もしく
は、燃料として使用される。この時、ガスは多量の顕熱
を持っていることから、この顕熱を蒸気発生等の熱とし
て有効利用しても良い。Further, the gas from the combustion of coal is collected via the exhaust gas duct 12, the dust in the gas is removed by a dust collector, and is used as reducing gas for preliminary reduction of ore or as fuel in the preliminary reduction furnace 10. Ru. At this time, since the gas has a large amount of sensible heat, this sensible heat may be effectively used as heat for steam generation, etc.
次に、溶融還元の操業が進行していくと炉内に溶銑とス
ラグが蓄積していくことから、定期的に溶銑およびスラ
グは排出される。Next, as the smelting reduction operation progresses, hot metal and slag accumulate in the furnace, so the hot metal and slag are periodically discharged.
第２図は１００Ｔ浴の溶融還元炉にて、溶融還元に用い
る炭材の二次燃焼率と、同着熱効率の関係を調査した結
果を示す。FIG. 2 shows the results of an investigation into the relationship between the secondary combustion rate of the carbon material used for melt reduction and the heat transfer efficiency in a melt reduction furnace with a 100T bath.
この実験では、炭材としては、ＶＭを含まないものとし
て、コークス、ＶＭを１７％含む半無煙炭およびＶＭを
３１％含む一般炭の３種類の炭材を使用した操業を示す
。第２図かられかるように、ＶＭを含まないコークスで
は、二次燃焼率６０％までは着熱効率が９０〜９５％で
あるのに対して、半無煙炭では二次燃焼率５５％から着
熱が悪化している。In this experiment, an operation using three types of carbon materials including coke, semi-anthracite coal containing 17% VM, and steam coal containing 31% VM will be shown. As can be seen from Figure 2, with coke that does not contain VM, the heat transfer efficiency is 90-95% up to a secondary combustion rate of 60%, whereas with semi-anthracite coal, heat transfer efficiency is from 55% to a secondary combustion rate. is getting worse.
また、ＶＭを３１％含む一般炭では二次燃焼率が約４５
％から着熱が悪化していることが認められる。In addition, the secondary combustion rate of steam coal containing 31% VM is approximately 45%.
%, it is recognized that heat transfer has worsened.
更に本発明者らは、溶融還元炉における流体の流動と反
応をシミュレーションした。Furthermore, the present inventors simulated the fluid flow and reaction in a smelting reduction furnace.
その結果を第３図に示す。The results are shown in FIG.
即ちこのシミュレーションの条件と同様の操業を行った
結果、１００Ｔ７８Ｅｊ１還元炉において、通常製鉄に
用いられる耐火物の中で最も高温に強くかつ酸化性のガ
ス雰囲気に強い材質として、ｘｉｇＯ−Ｃｒ２０３から
なる煉瓦を炉の上部に張付けた。That is, as a result of carrying out operations similar to the conditions of this simulation, in a 100T78Ej1 reduction furnace, bricks made of xigO-Cr203 were found to be the most resistant to high temperatures and resistant to oxidizing gas atmospheres among the refractories normally used in steelmaking. was attached to the top of the furnace.
この試験結果では、損耗速度は溶融還元の操業時間に対
して、２〜５ｍｍ／Ｈｒと非常に大きい。According to the test results, the wear rate is extremely large, 2 to 5 mm/Hr, relative to the operation time of melt reduction.
特に炉の上部空間の壁際が、ガス温度が２０００’Ｃ以
上と最も高く、かつガスが上昇流を形成している。また
、煉瓦の損耗速度もこの部位が最も大きい。In particular, the gas temperature is the highest at 2000'C or more near the wall of the upper space of the furnace, and the gas forms an upward flow. This area also has the highest rate of brick wear.
又炉内上部空間のガスの流れは、炉壁から中心方向１／
３以内は上昇流であり、炉中心から２／３内は下降流で
あることを確認した。Also, the gas flow in the upper space inside the furnace is from the furnace wall to the center direction.
It was confirmed that the flow within 3 was an upward flow, and the flow within 2/3 from the center of the furnace was a downward flow.
従って本発明においては、炉壁から中心方向１／３以内
の炉内ガス上昇流に粉状の原料を吹込むこととする。Therefore, in the present invention, the powdered raw material is blown into the upward flow of gas in the furnace within 1/3 of the furnace wall in the direction of the center.
第３図中左は温度（℃）、右はガス流速（ｍ／５ｅｅ）
を−は上昇流、＋は下降流を示す。In Figure 3, the left is temperature (℃), the right is gas flow velocity (m/5ee)
- indicates upward flow, + indicates downward flow.
溶融還元炉では、石炭に後述の方法で製造するチャー（
石炭の乾溜物）を混合して、使用する炭材の平均ＶＭを
低下させ、高二次燃焼率の操業を実施する。この場合の
二次燃焼率は、４０〜５０％とすることが望ましいが、
５０％以上でも実施は可能である。In the smelting reduction furnace, coal is mixed with char (which is produced by the method described below).
(dry distillate of coal) is mixed to lower the average VM of the carbon material used and to operate with a high secondary combustion rate. The secondary combustion rate in this case is preferably 40 to 50%, but
It is possible to implement it even if it is 50% or more.
ここで、二次燃焼率が高いため、溶融還元炉上部のガス
温度は２０００℃以上となる。この高温のガスの顕熱を
有効利用することを目的として、この部分、つまり炉内
の上部空間に、粉体供給タンク６から粉体吹込みノズル
７を介して粉炭、粉鉱石、粉石灰石等の粉状原料を吹込
み、高温のガスによりこの粉状原料を加熱し、反応させ
る。これによってガスの冷却が可能となる。Here, since the secondary combustion rate is high, the gas temperature in the upper part of the smelting reduction furnace is 2000° C. or higher. In order to effectively utilize the sensible heat of this high-temperature gas, powdered coal, powdered ore, powdered limestone, etc. A powdery raw material is blown into the reactor, and the powdery raw material is heated by high-temperature gas and reacted. This allows cooling of the gas.
更に粉状原料が粉炭である場合はその効果が大きく、高
温のガスと接触することにより、粉炭は乾留するととも
にガスを改質し、このときの反応によりガス温度を著し
く低下させることができる。Furthermore, when the powdered raw material is powdered coal, the effect is great, and when it comes into contact with high-temperature gas, the powdered coal is carbonized and the gas is reformed, and the reaction at this time can significantly lower the gas temperature.
以下粉炭の吹込みを例として説明する。The following will explain the injection of powdered coal as an example.
第４図は第１図の部分拡大図である。FIG. 4 is a partially enlarged view of FIG. 1.
吹込みノズルを第５図に模式的に示した。図中矢印で粉
炭吐出方向を示す。７は吹込みノズル、１Ｇは噴出口で
ある。The blowing nozzle is schematically shown in FIG. The arrow in the figure indicates the direction of pulverized coal discharge. 7 is a blowing nozzle, and 1G is a spout.
尚、第４図に示す角度θは、噴出口１６の中心線ｘ１と
炉壁に平行な線ｘ２とで形成される角であり、炉壁に対
する粉炭の噴出方向を表わすものである。Incidentally, the angle θ shown in FIG. 4 is an angle formed by the center line x1 of the jet nozzle 16 and a line x2 parallel to the furnace wall, and represents the direction in which the pulverized coal is jetted with respect to the furnace wall.
吹込まれた粉炭は高温のガスにより急速に加熱されて、
速やかに石炭のＶＭを発生する。このＶＭの発生速度は
石炭の粒径によっても異なるが、ある粒度以下の粉炭で
は、伝熱が速いことからＶＭの分離速度も速く、０．２
〜２秒程度の短時間でＶＭの分離は終了する。粉炭の粒
径を限定した理由は後で述べる。The injected pulverized coal is rapidly heated by high-temperature gas,
Promptly generate VM of coal. The rate of generation of VM varies depending on the particle size of the coal, but for powdered coal below a certain particle size, heat transfer is fast, so the separation rate of VM is also fast, 0.2
The separation of VMs is completed in a short time of about 2 seconds. The reason for limiting the particle size of the powdered coal will be discussed later.
また、ＶＭが放出される形態は炭化水素、−酸化炭素お
よび水素から構成されるガスであるが、本発明での溶融
還元炉内のような２０００℃以上といった高温では、コ
ークス炉等の石炭乾溜炉とは異なり、タールの生成はほ
とんど認められず、本発明の操業では、タール処理が不
要である利点も有している。このＶＭが石炭から放出さ
れた直後に、このガスは炉から発生する比較的酸化度が
高く、温度の高いガスと反応する。石炭から発生するガ
スの内で溶融還元炉からのガスと反応するガス種は炭化
水素であり、炭化水素は発生ガスの二酸化炭素と水蒸気
と改質反応を起こし、水素と一酸化炭素に分解される。In addition, VM is released in the form of a gas composed of hydrocarbons, carbon oxides, and hydrogen, but at high temperatures of 2000°C or higher, such as in the smelting reduction furnace of the present invention, it is Unlike a furnace, almost no tar is produced, and the operation of the present invention also has the advantage of not requiring tar treatment. Immediately after this VM is released from the coal, it reacts with the relatively highly oxidized and hot gases emanating from the furnace. Among the gases generated from coal, the gas species that reacts with the gas from the smelting reduction furnace is hydrocarbons. Hydrocarbons undergo a reforming reaction with carbon dioxide and water vapor in the generated gas, and are decomposed into hydrogen and carbon monoxide. Ru.
この反応は、下式の例に示されるように吸熱反応であり
、この反応が発生することから炉内のガスの平均温度は
低下する。This reaction is an endothermic reaction as shown in the example of the formula below, and as this reaction occurs, the average temperature of the gas in the furnace decreases.
ＣＨ４＋ＣＯ２→２ＣＯ＋２Ｈ２
つまり、石炭乾溜とガス改質の反応を溶融還元炉からの
発生するガスの顕熱を利用して行うことができ、排熱回
収を行うと同時に、ガスを冷却することができる。CH4+CO2→2CO+2H2 In other words, the reaction of coal dry distillation and gas reforming can be performed using the sensible heat of the gas generated from the smelting reduction furnace, and the gas can be cooled at the same time as exhaust heat recovery.
次に、本発明による１００Ｔ鉄浴０溶融還元炉における
操業の例を説明する。Next, an example of operation in a 100T iron bath zero smelting reduction furnace according to the present invention will be explained.
まず、溶融還元炉には、鉄源として予備還元鉱、および
一般炭とこの一般炭を乾溜して得られたチャーの混合物
を連続して供給する。また、スラグの成分を調整する副
原料として生石灰も予備還元鉱と混合して供給する。酸
素は全量上吹ランスから吹付けられ、鉄浴およびスラグ
浴の撹拌のために窒素ガスを炉底部の羽口から供給する
。First, the smelting reduction furnace is continuously supplied with a pre-reduced ore as an iron source, and a mixture of steam coal and char obtained by dry distilling the steam coal. In addition, quicklime is also mixed with the preliminary reduced ore and supplied as an auxiliary raw material for adjusting the components of the slag. Oxygen is fully blown from the top blowing lance, and nitrogen gas is supplied from the tuyere at the bottom of the furnace for stirring the iron bath and slag bath.
溶融還元炉の操業では、比較的高二次燃焼の操業を行い
、二次燃焼率は４７．６％であり、この時の発生ガスｆ
ｆ１ｆｆｉは、５７９０ＯＮｍ３／ Ｈであった。粉炭
は粉体供給タンク６から吹込みノズル７を用いて炉内に
吹込んだ。吹込みノズル７はスラグ面から約１ｍの高さ
に円周方向に均等に８本配置した。In the operation of the smelting reduction furnace, a relatively high secondary combustion operation is performed, and the secondary combustion rate is 47.6%, and the gas generated at this time f
f1ffi was 5790 ONm3/H. Powdered coal was blown into the furnace from a powder supply tank 6 using a blowing nozzle 7. Eight blowing nozzles 7 were arranged evenly in the circumferential direction at a height of about 1 m from the slag surface.
これらの吹込みノズル７は、第５図（ｂ）に示される形
状のもので、先に示Ｕた炉内のガス流れの分布図の解析
結果に基づき、粉炭が飛散し易いように、炉壁に向かっ
て平行につまり前記角度θを零として、鉛直上方の半円
の扇状に吹込んだ。These blowing nozzles 7 have the shape shown in FIG. The air was blown parallel to the wall, that is, with the angle θ set to zero, in a vertically upward semicircular fan shape.
吹込まれた粉炭はこの操業条件での石炭の飛散粒径より
も小さい、２關以下に調整した。粉炭は炉内および排ガ
スダクト内で乾溜されて、そのＶＭが大幅に減少された
。表−２に示されるように、排ガスダクト出口の集塵機
で捕集された炭素系のダクトは、はとんどＶＭを含んで
いないことが判った。つまり、吹込まれた粉炭は十分に
乾溜されて、はとんどＶＭを含まないチャー状の炭材に
変化していた。The injected powdered coal was adjusted to a size smaller than 2 degrees, which is smaller than the scattered particle size of the coal under these operating conditions. The pulverized coal was dry distilled in the furnace and in the exhaust gas duct, and its VM was significantly reduced. As shown in Table 2, it was found that the carbon-based duct collected by the dust collector at the exhaust gas duct outlet hardly contained VM. In other words, the injected powdered coal was sufficiently dry distilled and changed into a char-like carbon material containing almost no VM.
また、この粉炭を吹込んだことによるＶＭによるガスの
改質の効果を炉内のサンプリングガスと排ガスダクト出
口のガスの成分の比較から求めた。In addition, the effect of gas reforming by VM caused by injecting this powdered coal was determined from a comparison of the components of the sampling gas in the furnace and the gas at the outlet of the exhaust gas duct.
この結果を次の表−３に示す。The results are shown in Table 3 below.
炉内のガスの酸化度は、０．４７６であったが、粉炭の
ＶＭがガスの二酸化炭素および水蒸気と反応した結果、
排ガスダクト出口では０．３４５に低減されており、発
生ガスが鉱石の予備還元に適当な酸化度まで改質されて
いることが判明した。また、排ガスダクト出口で採取し
たガスには、メタン、エタン等の炭化水素は検出されな
かった。このことから、排ガスとＶＭは、はぼ完全に排
ガスダクト内で反応を終了していることが判明した。The degree of oxidation of the gas in the furnace was 0.476, but as a result of the VM of the powdered coal reacting with the carbon dioxide and water vapor of the gas,
At the exit of the exhaust gas duct, the oxidation level was reduced to 0.345, indicating that the generated gas had been reformed to an oxidation degree suitable for preliminary reduction of ore. Furthermore, hydrocarbons such as methane and ethane were not detected in the gas sampled at the exhaust gas duct outlet. From this, it was found that the reaction between the exhaust gas and VM was almost completely completed within the exhaust gas duct.
この操業の時のガスの温度についても測定を実施した。The temperature of the gas during this operation was also measured.
炉上部の煉瓦壁周囲のガス温度と排ガスダクト出口の温
度を測定した。また、比較のためにほぼ同等の溶融還元
炉の操業を行い、粉炭を吹込まなかった従来法による操
業例での測定結果も表−１に示した。The gas temperature around the brick wall at the top of the furnace and the temperature at the exhaust gas duct outlet were measured. For comparison, Table 1 also shows the measurement results of an example of operation using a conventional method in which almost the same smelting reduction furnace was operated and no pulverized coal was injected.
表−１から判るように、従来法と比較して、溶融還元炉
の操業条件はほぼ同等であるが、炉内および排ガスダク
ト出口のガス温度に差があり、粉炭を吹込み、ガス改質
を行った本発明の操業法では、炉内の平均ガス温度は、
約１１０℃低下し、また排ガスダクト出口のガス温度は
約１６０℃低下している。As can be seen from Table 1, compared to the conventional method, the operating conditions of the smelting reduction furnace are almost the same, but there is a difference in gas temperature inside the furnace and at the exit of the exhaust gas duct. In the operating method of the present invention, the average gas temperature in the furnace is
The temperature of the gas at the outlet of the exhaust gas duct has decreased by approximately 160°C.
つまり、粉炭を吹込み石炭の乾溜でガス改質を行った結
果、乾溜熱およびガス改質の吸熱にガスの顕部を効果的
に利用できていることが示されている。In other words, as a result of gas reforming by blowing powdered coal and dry distillation of coal, it has been shown that the sensitive part of the gas can be effectively utilized for the heat of dry distillation and the heat absorption of gas reforming.
次に、石炭が効率的に乾溜されていることが本発明の操
業において重要であるが、本発明者らの研究により、石
炭の反応率は石炭粒径に強く影響されることも解明され
た。ガス改質に使用する石炭の粒径については、本発明
で効果的に利用できる条件として、まず第一に、ガスと
粉炭の接触時間を確保するために、粉炭は発生ガスに同
伴されて、炉内から排ガスダクトに飛散されることが望
ましく、実施例ではこの条件を満たす石炭粒径と吹込条
件で操業を行った。Next, although it is important for the operation of the present invention that the coal be efficiently dry distilled, the inventors' research also revealed that the reaction rate of the coal is strongly influenced by the coal particle size. . Regarding the particle size of the coal used for gas reforming, the conditions that can be effectively used in the present invention are, first of all, in order to ensure the contact time between the gas and the pulverized coal, the pulverized coal is entrained in the generated gas, It is desirable that the coal be dispersed from inside the furnace to the exhaust gas duct, and in the Examples, operations were carried out under coal particle diameters and blowing conditions that satisfied this condition.
つまり、発生ガスの上昇流により、ガスと同伴していく
粒径の石炭を吹込むことにより、粉炭は高温のガスとと
もに排ガスダクト内を移動することから、石炭と高温の
ガスの接触時間が増加して、粉炭は乾溜されやすくなる
。In other words, by injecting coal with a particle size that accompanies the gas due to the upward flow of generated gas, the powdered coal moves in the exhaust gas duct together with the high-temperature gas, increasing the contact time between the coal and the high-temperature gas. As a result, powdered coal is easily dry distilled.
まず、本発明者らは、石炭粒径とガス改質効果に関係が
あることを見出した。また、ガス改質の効率の良い実験
においては、排ガス中のダクトにより多くの粉状のチャ
ーが混入している事実を突き止め、粉炭の飛散とガス改
質の比較試験を実施した。First, the present inventors discovered that there is a relationship between coal particle size and gas reforming effect. In addition, in an experiment to improve the efficiency of gas reforming, it was discovered that a large amount of powdered char was mixed into the ducts in the exhaust gas, and a comparative test was conducted between scattering of powdered coal and gas reforming.
この結果を表 ４に示す。Show this result 4.
表 −４
実験条件
排ガスａＱ ５７３０ＯＮｍ３７１１．吹込石炭ｆｆ
ｉ理論ガス酸化度低下−１２，８％
１１、ｏｔ／ｈ。Table-4 Experimental conditions Exhaust gas aQ 5730ONm3711. Blown coal ff
i Theoretical gas oxidation degree decrease - 12.8% 11, ot/h.
テスト−Ａ ＜１．０ ８９．５ １１
．９ ９３．０＊）（実績のガス酸化度低下）／（理
論ガス酸化度低下）つまり、粉炭が飛散率の高い粒径の
小さい石炭の方かガス改質が効率的に実施されている事
実を解明した。Test-A <1.0 89.5 11
．． 9 93.0*) (Actual gas oxidation degree decrease) / (Theoretical gas oxidation degree decrease) In other words, the fact that gas reforming is carried out more efficiently in coal with a small particle size that has a high scattering rate. was clarified.
ここで、本発明者らは、石炭の飛散率を予想するために
、石炭のガス中で受ける上向きの力と重力を比較検討し
た結果、次の関係が成り立つことを求めた。Here, in order to predict the scattering rate of coal, the present inventors compared and studied the upward force exerted in coal gas and gravity, and found that the following relationship holds true.
粉炭は次の（１）式で求められる粒径、つまり、排ガス
ダクト内の排ガスの流速と石炭の終末沈降速度（石炭が
ガス中を自由落下する際の無限時間後の落下速度）が等
しい粒径よりも小さいことが望ましいことが判明した。Powdered coal has a particle size determined by the following equation (1), that is, the particle size is equal to the flow velocity of exhaust gas in the exhaust gas duct and the final settling velocity of coal (the falling velocity after an infinite time when coal falls freely through gas). It has been found that it is desirable to be smaller than the diameter.
２ ’ ２ １／２ｕ＝
（４ｇ Ｃｐ −ｐ ） Ｄｐ３ ／２２５
μρ）９ｇ
（１）
ここで、
Ｕ ：終末沈降速度、
μ ：ガスの粘度、
Ｄｐ：粒径、
ρ ：ガス密度、
ρ ：石炭密度、
石炭の場合、見掛は密度は１．３〜１，６であることと
、（１）式にこの数値を代入した（２）式の値か条件と
なる。また、１．８００℃の温度での炉口でのガスの物
性値を用いて、Ｄｐを計算すると、２／３
Ｄｐ＝０．４７・Ｖ （ｍｍ） （
２）（Ｖ：排ガスダクト内ガス流速（ｍ／５ｅｅ））と
なり、このＤｐよりも小さい粒径の石炭を吹込めば、石
炭は炉内から排ガスダクトへガスとともに同伴されて、
効果的に乾溜・ガス改質が行われる。2' 2 1/2u=
(4g Cp -p) Dp3 /225
μρ) 9g (1) Where, U: Terminal sedimentation velocity, μ: Gas viscosity, Dp: Particle size, ρ: Gas density, ρ: Coal density, In the case of coal, the apparent density is 1.3 to 1. , 6, and the value of equation (2), which is obtained by substituting this numerical value into equation (1). Also, when calculating Dp using the physical property values of the gas at the furnace mouth at a temperature of 1.800°C, 2/3 Dp=0.47・V (mm) (
2) (V: gas flow velocity in the exhaust gas duct (m/5ee)), and if coal with a particle size smaller than this Dp is injected, the coal will be entrained with the gas from the furnace to the exhaust gas duct,
Dry distillation and gas reforming are carried out effectively.
この関係式に表−４の実験条件をあてはめれば、Ｖ＝４
．０ｍ／ｓとなり、Ｄｐは１．２關となる。つまり、テ
スト−Ａでは、粉炭は飛散される条件であったのに対し
て、テスト−Ｂでは、粉炭は飛散されずらい試験条件で
あったことが判明した。このことは、粉炭の飛散率の差
にも表れている。If we apply the experimental conditions in Table 4 to this relational expression, V=4
．． The speed becomes 0 m/s, and Dp becomes 1.2 degrees. In other words, it was found that in Test-A, the conditions were such that pulverized coal was scattered, whereas in Test-B, the test conditions were such that pulverized coal was difficult to be scattered. This is also reflected in the difference in the scattering rate of powdered coal.
また、石炭の乾溜とガスとの反応は、ガスが高温の排ガ
スダクト内で終了する必要があるが、発生ガス処理の排
ガスダクトは１５〜３０ｍの設計が通常であり、かつ、
ガスの流速の設計条件は、１０〜２０ｍｍ／ｓであるこ
とから、石炭がガスとともに排ガスダクト内の滞留時間
は１〜２秒となり、本発明に規定される石炭の粒径は、
排ガスダクト内で石炭の乾溜は完全に終了することが可
能な条件を満たす必要がある。つまり、炉内から排ガス
ダクトの出口の間でのガスと粉炭の接触時間は２秒程度
であることから、この時間内に粉炭の乾溜は終了してい
なければならない。In addition, the reaction between the dry distillation of coal and the gas needs to be completed in the exhaust gas duct where the gas is at high temperature, but the exhaust gas duct for processing the generated gas is usually designed to be 15 to 30 m long, and
Since the design condition for the gas flow velocity is 10 to 20 mm/s, the residence time of coal and gas in the exhaust gas duct is 1 to 2 seconds, and the particle size of coal specified in the present invention is:
It is necessary to satisfy conditions that allow dry distillation of coal to be completely completed in the exhaust gas duct. That is, since the contact time between the gas and the pulverized coal between the inside of the furnace and the outlet of the exhaust gas duct is about 2 seconds, the dry distillation of the pulverized coal must be completed within this time.
一方、石炭の乾溜時間は粒径に強く依存することを本発
明者らは研究で解明した。つまり、排ガスダクト内で乾
溜が終了するための石炭粒径を求めるために、高温ガス
内での乾溜実験を行った。On the other hand, the present inventors have discovered through research that the dry distillation time of coal strongly depends on the particle size. In other words, in order to determine the coal particle size required to complete dry distillation in the exhaust gas duct, we conducted a dry distillation experiment in high-temperature gas.
この結果を表−５に示す。The results are shown in Table-5.
石炭の乾溜は伝熱が律速となるため、内部まで急速に加
熱されやすい微粉炭の方が乾溜時間は短くなった。この
結果、約２秒間で残留ＶＭが２％になるためには、石炭
の粒径が２ｍｍ以下であれば良いことを解明した。Heat transfer is the rate-limiting factor in dry distillation of coal, so the dry distillation time was shorter for pulverized coal, which is more likely to be heated rapidly to the inside. As a result, it was found that in order to reduce the residual VM to 2% in about 2 seconds, the particle size of the coal should be 2 mm or less.
表 −５
実験条件；窒素ガス雰囲気でガス温度１４００℃の電気
炉の中に所定の粒径の一般炭を
投入して、２秒後の成分を調査した。Table 5 Experimental conditions: Steam coal of a predetermined particle size was put into an electric furnace at a gas temperature of 1400° C. in a nitrogen gas atmosphere, and the components were investigated after 2 seconds.
石炭粒径（ａ＋ｍ）
１．０
１．５
２．０
２．７
３．５
５．０
以上の事実から、
本発明者らは、
粉炭を効果的
にガス改質に利用するためには、まず、粉炭がガスに同
伴して排ガスダクト内を上昇すべきこと、粉炭の粒径は
、排ガスダクト内で反応が終了するほど小さいことの２
点が本発明の重要な要件であることを解明した。Coal particle size (a+m) 1.0 1.5 2.0 2.7 3.5 5.0 Based on the above facts, the present inventors believe that in order to effectively utilize powdered coal for gas reforming, First, the pulverized coal should rise along with the gas in the exhaust gas duct, and the particle size of the pulverized coal must be small enough to complete the reaction within the exhaust gas duct.
It has been clarified that this point is an important requirement of the present invention.
また、溶融還元炉へ吹込む粉炭が耐火物を保護する効果
をもたらすためには、粉炭は炉内に吹込まれなければな
らず、炉内のガスの上昇部分に吹込まれる必要がある。In addition, in order for the pulverized coal blown into the smelting reduction furnace to have the effect of protecting the refractories, the pulverized coal must be blown into the furnace and must be blown into the rising portion of the gas in the furnace.
つまり、石炭の粒径、吹込み位置および吹込み方向がガ
ス改質効果を得るためには、重要であることが分かった
。In other words, it was found that the particle size of coal, the injection position, and the injection direction are important in order to obtain the gas reforming effect.
つまり、炉内のガス流れの解析結果を基に考察すると、
本発明での粉炭を発生ガスに同伴させ、ガスの顕熱を利
用して乾溜しようとする操業においては、粉炭は壁際の
上昇流の中に、適当な粒径で吹込まれなければならない
。In other words, based on the analysis results of the gas flow inside the furnace,
In the operation of the present invention in which pulverized coal is entrained in the generated gas and dry distillation is attempted using the sensible heat of the gas, the pulverized coal must be blown into the upward flow near the wall in an appropriate particle size.
粉炭が排ガスダクト内に飛散する吹込み条件が、粉炭が
排ガスダクト内でガスに同伴されるか、粉炭が排ガスダ
クト内で反応が終了するか否かの３項目を条件差として
、ガス改質効果を比較した結果を表−６の実施例に示し
た。Gas reforming is performed based on three conditions: whether the pulverized coal is dispersed into the exhaust gas duct, whether the pulverized coal is entrained in the gas in the duct, and whether the reaction of the pulverized coal is completed within the duct. The results of comparing the effects are shown in Examples in Table 6.
表−６の実施例１では、粉炭がガスの上昇流に同伴され
る吹込み条件で、かつ、排ガスの流速よりも石炭の終端
速度が遅い粒径である１、２ｍｍ以下の石炭を使用し、
また、比較例２では同一のノズルを使用して、石炭の粒
径を１．５〜２關として、Ｄｐよりも大きい、飛散しず
らい石炭を使用した。In Example 1 shown in Table 6, the blowing conditions were such that the powdered coal was accompanied by the upward flow of gas, and coal with a particle size of 1 to 2 mm or less was used, and the terminal velocity of the coal was slower than the flow velocity of the exhaust gas. ,
Further, in Comparative Example 2, the same nozzle was used, the particle size of coal was set to 1.5 to 2 degrees, and coal that was larger than Dp and hard to scatter was used.
実施例１では、９０％以上の石炭飛散率でガス改質効果
も大きいのに対して、比較例２では、石炭飛散率が半分
しかなく、ガス改質効果も５０％程度しかないことから
、石炭乾溜およびガス改質が効率的に実施できなかった
ことが判る。In Example 1, the coal scattering rate was 90% or more and the gas reforming effect was large, whereas in Comparative Example 2, the coal scattering rate was only half, and the gas reforming effect was only about 50%. It can be seen that coal dry distillation and gas reforming could not be carried out efficiently.
本発明において、吹込む粉炭の粒径を２■もしくは、ガ
ス回収装置内のガス流速により吹飛ばされる粒径のいず
れかよりも、小さいこととしたのは以上の理由による。In the present invention, the particle size of the blown coal is set to be smaller than either 2 mm or the particle size blown away by the gas flow rate in the gas recovery device for the reasons described above.
次に、粉炭の吹込み位置と吹込み条件も本発明において
は重要な要件である。Next, the pulverized coal injection position and injection conditions are also important requirements in the present invention.
先に示した第３図の如く、炉内のガスの流れは一様でな
く、炉の中心部は上吹ランスから吹付ける酸素ガスジェ
ットの影響を受けて、下降流となっている。また発生ガ
スは壁際を上昇する。As shown in FIG. 3 above, the flow of gas in the furnace is not uniform, and the center of the furnace is influenced by the oxygen gas jet blown from the top blowing lance, resulting in a downward flow. Also, the generated gas rises along the wall.
第３図において判るように、炉壁の周囲、炉の中心から
見て２／３の位置が上昇流と下降流の境界となっている
。また、このような上昇流と下降流が生じているのは炉
内に限られ、特に−１０ｍ ／Ｓ以上の強い上昇流が生
じているのは、スラグ上面１４ａ （第１図）を基準と
すると、炉内半径の約１．５倍の高さ迄である。As can be seen in FIG. 3, the boundary between the upward flow and the downward flow is located around the furnace wall, two-thirds of the way from the center of the furnace. Furthermore, such upward and downward flows occur only within the furnace, and in particular, strong upward flows of -10 m/S or more occur when the slag upper surface 14a (Fig. 1) is used as a reference. Then, the height is approximately 1.5 times the radius inside the furnace.
このガスの流動シミュレーションの結果を反映して、前
記−１（１ｍ／ｓ以上の上昇流が生じている炉の中心か
ら見て、２／３よりも炉壁側に吹込むノズルと、この範
囲より炉の中心側に向かって吹込むノズルによって粉炭
を吹込む比較試験を実施した。Reflecting the results of this gas flow simulation, we decided to design a nozzle that injects air closer to the furnace wall than 2/3 when viewed from the center of the furnace where an upward flow of -1 (1 m/s or more is occurring) and this area. A comparative test was conducted in which powdered coal was injected using a nozzle that injected coal toward the center of the furnace.
表−６における実施例１は、第５図（ａ）に示される吹
込みノズル７ａの形状で、前記炉壁に対する角度θを１
０’とした吹込みノズル（以下この吹込み条件のノズル
を、吹込みノズルＡと言う）を用い、炉口の壁から４３
０ ｉｎまでのところに粉炭を吹込んだものであり、炉
口の内径が３ｍであることから、前述した上昇流への吹
込み条件を満たしている。Example 1 in Table 6 has the shape of the blowing nozzle 7a shown in FIG. 5(a), and the angle θ with respect to the furnace wall is 1.
Using a blowing nozzle set to 0' (hereinafter, the nozzle with this blowing condition will be referred to as blowing nozzle A),
Since pulverized coal was injected up to 0 in. and the inner diameter of the furnace mouth was 3 m, it satisfied the above-mentioned conditions for blowing into an upward flow.
次に実施例２は、第５図（ｂ）に示される吹込みノズル
７ｂの形状で、前記炉壁に対する角度θをＯ″とした吹
込みノズル（以下この吹込み条件のノズルを、吹込みノ
ズルＢと言う）を用いて、炉口の壁から１００ｍｍの位
置で炉壁に平行に、かつ上方１８０°の角度で扇形に粉
炭を吹込んだものである。Next, in Example 2, the shape of the blowing nozzle 7b shown in FIG. Using a nozzle B), powdered coal was injected in a fan shape at a position 100 mm from the wall of the furnace mouth, parallel to the furnace wall, and at an angle of 180° upward.
本実施例も前記実施例１と同様に本発明の吹込み条件を
満たしている。Like Example 1, this example also satisfies the blowing conditions of the present invention.
一方、比較例１は、第５図（ｃ）に示される吹込みノズ
ル７ｃの形状で、炉口の壁から８００ｍｍのところに吹
込めるよう前記炉壁に対する角度θを１８″とした吹込
みノズル（以下この吹込み条件のノズルを、吹込みノズ
ルＣと言う）での試験結果である。この比較例１では、
炉壁から１７３の位置の条件を満たしていない。On the other hand, in Comparative Example 1, the blowing nozzle 7c has the shape shown in FIG. (Hereinafter, the nozzle under this blowing condition will be referred to as blowing nozzle C.) In this comparative example 1,
The condition for position 173 from the furnace wall is not met.
表−６に示すようにこの比較試験の結果では、吹込みノ
ズルＡおよびＢを使用した場合、粉炭が排ガスダクト後
の集塵磯で捕集される比率は９０％以上であるが、吹込
みノズルＣを使用した比較例１の場合では、約７０％と
低く、またガスの改質も十分に成されていないことが判
明した。As shown in Table 6, the results of this comparative test show that when blowing nozzles A and B are used, the ratio of pulverized coal being collected at the dust collecting rock after the exhaust gas duct is over 90%; In the case of Comparative Example 1 using Nozzle C, the ratio was as low as about 70%, and it was found that gas reformation was not sufficiently achieved.
本発明において粉炭の吹込み方向を粉炭が炉内から排出
されるまでは炉壁から中心方向の（７３以内の空間にガ
ス改質用の粉炭を吹込むことと限定したのは、以上の理
由からである。The reason why in the present invention, the blowing direction of the pulverized coal is limited to injecting the pulverized coal for gas reforming into the space (within 73 cm) from the furnace wall toward the center until the pulverized coal is discharged from the furnace is as follows. It is from.
次に、粉炭は飛散するが、排ガスダクト内で反応が終了
しない粒径の粉炭を吹込んだ場合の比較試験の結果を比
較例３として示す。Next, Comparative Example 3 shows the results of a comparative test in which powdered coal was injected with a particle size that caused the powder to scatter but the reaction did not complete in the exhaust gas duct.
比較例３では、排ガスダクト内のガス流速を早くして、
排ガスダクト内で反応が終了しない粒径の粉炭も飛散す
る条件で実験を実施した。この結果粉炭は飛散している
ものの、ガスの改質反応は十分には進行しておらず、ガ
スの改質効果も約７０％に止まっている。In Comparative Example 3, the gas flow rate in the exhaust gas duct was increased,
The experiment was conducted under conditions in which powdered coal of a particle size that did not complete the reaction in the exhaust gas duct was scattered. As a result, although the powdered coal is scattered, the gas reforming reaction has not progressed sufficiently, and the gas reforming effect remains at about 70%.
また、本発明者らは、粉炭のノズル形状として、実施例
１．２以外にも種々、検討したが、粉炭を前述の条件で
飛散させれば、ガスの改質効果については、さほどの差
はないことが判明しており、また、炉形状として、第４
図に示すような炉上部のコーン部のない炉でも実施した
が、本発明の条件さえ満たしていれば、ガス改質が十分
効率的に実施されることも解明した。In addition, the present inventors have investigated various nozzle shapes for powdered coal other than Example 1.2, but if powdered coal is scattered under the above conditions, there is no significant difference in the gas reforming effect. It has been found that there is no
The experiment was also carried out using a furnace without a cone in the upper part of the furnace as shown in the figure, and it was also found that gas reforming could be carried out efficiently as long as the conditions of the present invention were met.
本発明により得られたガスを用いて一段式の流動層型予
備還元炉で鉄鉱石の予備還元を実施したところ、ガスの
酸化度が低減することから、高効率の操業が行えた。こ
の結果は表−７に示されており、従来法２の高二次燃焼
操業での予備還元率が９％であるのに対して、本発明で
の操業例では、同様に溶融還元炉では高二次燃焼である
にも関わらず予備還元が４０％まで向上されている。When iron ore was pre-reduced in a single-stage fluidized bed pre-reduction furnace using the gas obtained according to the present invention, highly efficient operation was possible because the degree of oxidation of the gas was reduced. The results are shown in Table 7, and while the preliminary reduction rate in the high secondary combustion operation of conventional method 2 is 9%, in the operation example of the present invention, the high secondary combustion Even though it is a secondary combustion, the preliminary reduction is improved to 40%.
本発明によるガスの改質により得られたガスは、通常、
１１００〜１３００℃であることから、予備還元炉の入
口で必要なガス温度の約１０００℃以上となっており、
ガス温度の調整には、少量の冷却ガスを混合したりする
簡単な操作ですみ、ガスを再加熱する必要はなくなった
。The gas obtained by reforming the gas according to the present invention is usually
Since the temperature is 1100 to 1300°C, the gas temperature is approximately 1000°C or higher, which is the required gas temperature at the entrance of the preliminary reduction furnace.
Adjusting the gas temperature requires a simple operation such as mixing a small amount of cooling gas, eliminating the need to reheat the gas.
つまり、本発明による予備還元の実施において、膨大な
ガスの冷却、再加熱の設備が不要にでき、予備還元炉と
溶融還元炉を熱ガスで直結しても、高効率の予備還元法
と、高二次燃焼率の溶融還元性を両立することができた
。In other words, in carrying out preliminary reduction according to the present invention, a huge amount of gas cooling and reheating equipment is not required, and even if the preliminary reduction furnace and the smelting reduction furnace are directly connected using hot gas, a highly efficient preliminary reduction method can be achieved. It was possible to achieve both high secondary combustion rate and melt reduction properties.
次に石炭以外の粉状原料を吹込んだ場合について説明す
る。Next, a case will be explained in which a powdery raw material other than coal is blown into the reactor.
先ず粉鉱石を吹込む操業について説明する。第５図（ａ
）の吹込みノズル７ａを用いて粉鉱石を吹込んだところ
炉壁に沿って流動し、炉内ガスから炉壁への輻射光を遮
断し、炉壁への入熱量が低下していることが判明された
。そこで炉上部より粉鉱石を炉壁に平行して、４００ｋ
ｇ／＋ｎｉｎの条件で吹込むとともに、炉壁煉瓦に熱流
束計を埋設し、炉壁への入熱量を測定した。First, we will explain the operation of injecting fine ore. Figure 5 (a
) When fine ore was injected using the injection nozzle 7a, it flowed along the furnace wall, blocking the radiation from the furnace gas to the furnace wall, and reducing the amount of heat input to the furnace wall. It was revealed that Therefore, fine ore was poured from the upper part of the furnace parallel to the furnace wall for 400km.
While blowing under the condition of g/+nin, a heat flux meter was embedded in the furnace wall brick to measure the amount of heat input to the furnace wall.
この結果、粉鉱石吹込み前の前記入熱量は１９、ＢＯＯ
ｋｃａｆ ／ｒｒｒ ・ｈｒであったのに対して、粉鉱
石吹込み後はＩＩ、０００ｋｃａｇ／ｒｒｒ・ｈｒと大
幅に低下していた。また、表−８に示すように炉壁近傍
のガス温度も粉鉱石吹込み前に比し、１１５℃低下して
いることが確認された。このような操業を実施した際の
耐火煉瓦の損耗速度は粉鉱石吹込みによって約半分にな
るなどその優れた効果が認められた。As a result, the amount of heat input before fine ore injection is 19, BOO
kcaf/rrr・hr, but after the injection of fine ore, it significantly decreased to II, 000 kcaf/rrr・hr. Furthermore, as shown in Table 8, it was confirmed that the gas temperature near the furnace wall was also lowered by 115°C compared to before the fine ore injection. When such operations were carried out, the rate of wear and tear of refractory bricks was approximately halved by injecting fine ore, demonstrating its excellent effects.
更に、粉炭、粉鉱石以外の粉状原料として、粉石灰石を
吹込んだ操業でも、吹込みノズル１本当たり約１５０ｋ
ｇ／ｒＡｉｎを吹込んだ場合、前述した粉鉱石の吹込み
と同様の効果が得られた。Furthermore, even in operations where powdered limestone is injected as a powdered raw material other than powdered coal and powdered ore, the injection nozzle costs approximately 150 kg.
When g/rAin was injected, the same effect as the above-mentioned injection of fine ore was obtained.
次に前述した条件で粉状原料を効率的に吹込むための吹
込みノズルについて説明する。Next, a blowing nozzle for efficiently blowing the powdery raw material under the above-mentioned conditions will be explained.
吹込みノズルは粉体による激しい摩耗作用を受けるとと
もに、炉内の高温ガスに晒されるなどきわめて苛酷な状
態で使用される。このため短期間で損耗し、その取替え
を余儀無くされている。The blowing nozzle is subjected to severe abrasion from the powder and is used under extremely harsh conditions, such as being exposed to high-temperature gas in the furnace. As a result, they wear out in a short period of time and have to be replaced.
この吹込みノズルの取替えにおいては、吹込みノズル周
辺の耐火物を損傷させることが多く、また取替えのため
に炉を冷却させる必要があることから、稼働率低下に繋
がるなど多くの問題を抱えていた。Replacement of the injection nozzle often causes damage to the refractories around the injection nozzle, and the furnace needs to be cooled down for replacement, which poses many problems, including a reduction in operating efficiency. Ta.
而して本発明においては、第６図に示すように、炉体１
の耐火煉瓦８、つまり炉壁上部に開口２１を論け、この
間口２１に前述した吹込みノズル７を進退可能に装着す
ることによって、前記問題を効果的に解決した。Accordingly, in the present invention, as shown in FIG.
The above-mentioned problem was effectively solved by forming an opening 21 in the upper part of the refractory brick 8, that is, the furnace wall, and installing the above-mentioned blowing nozzle 7 in this opening 21 so as to be able to move forward and backward.
吹込みノズル７を進退させるには、例えば前記開口２１
に近接して配設された架台２２上を、自在に走行する台
車２３で吹込みノズル７を保持するとともに、前記台車
２３に、液圧、気圧あるいは電動駆動方式のシリンダー
装置、又は電動モーター等の走行駆動装置２４を連設し
た機構とすることによって可能である。３０は粉原料供
給用のフレキシブルホースである。In order to move the blowing nozzle 7 forward and backward, for example, the opening 21
The blowing nozzle 7 is held by a trolley 23 that freely runs on a pedestal 22 disposed close to the chassis 22, and the trolley 23 is equipped with a hydraulic, pneumatic or electrically driven cylinder device, an electric motor, etc. This is possible by using a mechanism in which two travel drive devices 24 are arranged in series. 30 is a flexible hose for supplying powder raw materials.
また吹込みノズル７が進退する開口２１の周辺の耐火煉
瓦８０は、例えば前記水、気液混合体、圧縮気体等の冷
却媒体を流通する冷却盤８１．あるいは図示はしないが
冷却バイブを耐火煉瓦中に埋設するか、図示はしないが
耐火煉瓦８０の近傍の炉体（鉄皮）１を水冷構造とし、
耐火煉瓦８０を冷却するなどの冷却構造機構を備えさせ
た。The refractory bricks 80 around the opening 21 through which the blowing nozzle 7 advances and retreats are connected to a cooling plate 81 through which a cooling medium such as water, gas-liquid mixture, compressed gas, etc., flows. Alternatively, although not shown, a cooling vibe may be buried in the refractory bricks, or the furnace body (iron shell) 1 near the refractory bricks 80 may have a water-cooled structure, although not shown.
A cooling structure mechanism for cooling the refractory bricks 80 is provided.
このような構造とすることにより吹込みノズル７を稼働
中のみ炉体１に装着し、非稼働中は高温の炉体１から離
れたところで待機させることができる。また損耗した吹
込みノズル７を炉を冷却することなく取替えすることが
可能であり、更に耐火煉瓦８０の耐用寿命も大幅に延ば
すことができ、稼働率を著しく高めることができる。With such a structure, the blowing nozzle 7 can be attached to the furnace body 1 only when it is in operation, and can be kept on standby at a place away from the high-temperature furnace body 1 when it is not in operation. Further, it is possible to replace the worn out blowing nozzle 7 without cooling the furnace, and furthermore, the service life of the refractory bricks 80 can be greatly extended, and the operating rate can be significantly increased.
前記冷却構造機構としては、例えば第７図に示すように
、炉内側に開口面８２ａを有する複数個の冷却媒体噴出
管８２を埋設して構成したものが、後述するようにさら
に優れた機能を発揮する。For example, as shown in FIG. 7, the cooling structure is constructed by embedding a plurality of cooling medium ejection pipes 82 having an opening surface 82a inside the furnace, which has even better functions as described later. Demonstrate.
即ち冷却媒体をヘッダ一部８３を介して噴出管８２の炉
内側に位置する開口面８２ａから噴出させることにより
、吹込みノズル７近傍の耐火煉瓦８０をより強力に冷却
することが可能となる。That is, by ejecting the cooling medium from the opening surface 82a of the ejection pipe 82 located on the inside of the furnace through the header part 83, it becomes possible to more powerfully cool the refractory bricks 80 in the vicinity of the blowing nozzle 7.
加えて前記冷却媒体に酸素ガスを添加すれば、開口２１
近傍へのスラグ等の付着を抑制する副次的効果も得られ
る。この場合冷却媒体としては炉内に噴出されることか
ら窒素ガス、炭酸ガス、溶融還元炉からの発生ガスを冷
却したもの、圧縮気体に適宜量の水を添加した気水等を
用いることができる。In addition, if oxygen gas is added to the cooling medium, the opening 21
A secondary effect of suppressing the adhesion of slag etc. to the vicinity can also be obtained. In this case, the cooling medium can be nitrogen gas, carbon dioxide gas, cooled gas generated from the smelting-reduction furnace, or air water obtained by adding an appropriate amount of water to compressed gas, since it is injected into the furnace. .
（実 施 例）
溶融還元炉と予備還元炉を直結した一部プラントにおい
て本発明を実施した。(Example) The present invention was implemented in some plants in which a smelting reduction furnace and a preliminary reduction furnace were directly connected.
粉炭を用いた操業は第１図に示すように、溶融還元炉で
は、予備還元炉で酸化鉄を一部還元した鉱石を被還元鉄
源として使用し、また一般炭と本発明により得た同石炭
のチャーの混合物を炭材として使用する。溶融還元炉か
ら発生するガスを粉炭で改質して、これを高温のまま流
動層型の予備還元炉に導き、鉱石を一部還元する。As shown in Figure 1, the operation using pulverized coal is as follows: In the smelting reduction furnace, ore with partially reduced iron oxide in the pre-reduction furnace is used as a source of reduced iron, and steam coal and the oxidized iron obtained by the present invention are used as a source of reduced iron. A mixture of coal char is used as charcoal material. The gas generated from the smelting reduction furnace is reformed with powdered coal, and the gas is led to a fluidized bed pre-reduction furnace while still at high temperature, where the ore is partially reduced.
実施例としては、１００Ｔ浴の溶融還元設備を用いて、
鉄鉱石を溶融還元して溶銑を製遺した結果であり、操業
条件は３例ともに、同一の銘柄の鉱石、石炭を使用して
、溶銑温度−１５００℃、溶銑炭素は飽和、スラグの塩
基度−１，２〜１．３の条件で操業した結果である。As an example, using a 100T bath melting reduction equipment,
This is the result of melting and reducing iron ore to produce hot metal.The operating conditions for all three cases were the same brand of ore and coal, hot metal temperature -1500℃, hot metal carbon saturation, and slag basicity. This is the result of operation under conditions of −1.2 to 1.3.
経済的な操業の実施のため、溶融還元炉では、石炭にガ
ス改質の際に生成したＶＭをほとんど含まないチャーを
混合して使用することと粉炭の乾溜とガス改質により、
耐火煉瓦の損耗を抑えられる上限の二次燃焼率である約
５０％の操業をして、このガスをガス改質用の粉炭にて
ガスの酸化度および温度を低減して、効率的な予備還元
を実施した。In order to carry out economical operation, the smelting reduction furnace mixes coal with char, which contains almost no VM generated during gas reforming, and uses dry distillation of powdered coal and gas reforming.
We operate at a secondary combustion rate of approximately 50%, which is the upper limit that prevents wear and tear on the refractory bricks, and use powdered coal for gas reforming to reduce the degree of oxidation and temperature of the gas, making it an efficient reserve. Reduction was carried out.
粉炭によるガス改質を行わない従来法による操業の比較
例として、高二次燃焼率の操業と低二次燃焼率の操業の
２例を示す。As a comparative example of conventional operation without gas reforming using powdered coal, two examples are shown: operation with a high secondary combustion rate and operation with a low secondary combustion rate.
従来法１の操業では、溶融還元炉が低二次燃焼率操業で
あることから、溶融還元炉内のガス温度が約１７２０℃
に止まっており、煉瓦の損耗速度は小さい。また、予備
還元炉入口でのガス酸化度が低いことから、鉱石の予備
還元率は、４１％と高くできた。In the operation of conventional method 1, the smelting reduction furnace operates at a low secondary combustion rate, so the gas temperature in the smelting reduction furnace is approximately 1720°C.
The rate of wear and tear of the bricks remains low. In addition, since the degree of gas oxidation at the inlet of the preliminary reduction furnace was low, the preliminary reduction rate of the ore could be as high as 41%.
しかしながら、この操業においては、予備還元率は高い
ものの二次燃焼率が低いことから、溶融還元炉での熱の
発生量が少なく、生産性が低くなり、石炭原単位と酸素
原単位が多くなっており、経済的な溶銑の製造法ではな
いことがわかる。However, in this operation, the preliminary reduction rate is high but the secondary combustion rate is low, so the amount of heat generated in the smelting reduction furnace is low, productivity is low, and the coal consumption rate and oxygen consumption rate are high. This shows that it is not an economical method for producing hot metal.
また、従来法２では、高二次燃焼率操業であることから
、炉内のガス温度が約１９１０℃と高くなっている。こ
の結果、炉上部の煉瓦の損耗速度が３．２ｍ＋ｓ／Ｈｒ
と他の操業に比べて、約４倍と大きくなっており、煉瓦
原単位も５．７ｋｇ／Ｔと悪く、溶銑の製造の費用が増
加するとともに、煉瓦の補修の増加による設備の稼働率
の低下、整備費用の増加の問題があった。Furthermore, in Conventional Method 2, the gas temperature in the furnace is as high as about 1910° C. due to the high secondary combustion rate operation. As a result, the wear rate of the bricks in the upper part of the furnace was 3.2m+s/Hr.
This is about 4 times larger than other operations, and the brick consumption rate is also poor at 5.7 kg/T, which increases the cost of producing hot metal and lowers the operating rate of equipment due to the increase in brick repair. There was a problem of deterioration and increase in maintenance costs.
さらに、二次燃焼率が高いことから、予備還元炉の入口
のガス酸化度が高（、鉱石の予備還元率は、９％と低位
に止まっている。このように、二次燃焼率が高く、溶融
還元炉での熱の発生は多いものの、鉱石の予備還元率が
低いことから、生産性もさほど向上しておらず、石炭原
単位と酸素原単位も比較的多い操業結果となっている。Furthermore, because the secondary combustion rate is high, the degree of gas oxidation at the inlet of the preliminary reduction furnace is high (and the preliminary reduction rate of ore remains at a low level of 9%. Although the smelting reduction furnace generates a lot of heat, the preliminary reduction rate of the ore is low, so productivity has not improved much, and the coal consumption rate and oxygen consumption rate are relatively high. .
従来法による操業に対して、本発明での実施例では、溶
融還元炉のガスを溶融還元炉内および予備還元炉に送る
排ガスダクト内でガス改質を実施することから、高二次
燃焼と高予備還元を両立させることができ、かつ、粉炭
の吹込み条件を良好にしていることから、粉炭を効率的
に乾溜し、かつ、溶融還元炉から発生する高温のガスの
顕熱を有効に活用することで、特別に大掛かりなガス改
質の設備がいらない。In contrast to the conventional operation, in the embodiment of the present invention, the gas from the smelting reduction furnace is reformed in the exhaust gas duct that sends it to the smelting reduction furnace and the preliminary reduction furnace, resulting in high secondary combustion and high Since it is possible to achieve both preliminary reduction and favorable injection conditions for pulverized coal, it is possible to efficiently dry distill pulverized coal and effectively utilize the sensible heat of the high-temperature gas generated from the smelting reduction furnace. This eliminates the need for special large-scale gas reforming equipment.
また、石炭の乾溜とガス改質のために必要な熱を溶融還
元炉から排出される高温ガスの顕熱を利用することがで
きるため、設備費も安くすみ、またエネルギー的にも有
利である。In addition, the sensible heat of the high-temperature gas discharged from the smelting-reduction furnace can be used to generate the heat required for dry distillation of coal and gas reformation, which reduces equipment costs and is also advantageous in terms of energy. .
本発明による操業結果では、実施例に示すように予備還
元炉で約４０％の高予備還元率を実現できており、かつ
石炭の約２０％を乾溜して、生成したチャーを溶融還元
炉で石炭に混合して使用することから、二次燃焼に不利
な炭材のＶＭを低減して、溶融還元炉で高二次燃焼率で
も着熱効率を向上できた。According to the operation results of the present invention, as shown in the examples, a high pre-reduction rate of about 40% can be achieved in the pre-reduction furnace, and about 20% of the coal is dry distilled, and the generated char is transferred to the smelting reduction furnace. Since it is mixed with coal, the VM of the carbonaceous material, which is unfavorable to secondary combustion, can be reduced, and the heat transfer efficiency can be improved even at a high secondary combustion rate in a smelting reduction furnace.
また、溶融還元炉内の最もガス温度の高い炉の上部のガ
ス燃焼部に石炭を吹込み、乾溜とガス改質を行うことに
より、ガス温度を低下させ高二次燃焼率にもかかわらず
、煉瓦の損耗速度を低位に保つことができた。In addition, by injecting coal into the gas combustion section at the top of the furnace, where the gas temperature is the highest in the smelting reduction furnace, and performing dry distillation and gas reformation, the gas temperature is lowered and the bricks can be fired despite the high secondary combustion rate. We were able to keep the rate of wear and tear at a low level.
この結果、高予備還元鉱石を使用することにより、溶融
還元炉での溶銑ｔｏｎあたりの消費熱量を低減し、かつ
、高二次燃焼率の操業により酸素および石炭の単位Ω５
たりの発生熱量も多くでき、生産性も従来法による操業
よりも約２７％以上高く、酸素原単位・石炭原単位とも
に大幅に少なくなっている。As a result, by using highly pre-reduced ore, the amount of heat consumed per ton of hot metal in the smelting reduction furnace is reduced, and by operating at a high secondary combustion rate, the unit of oxygen and coal is Ω5.
The amount of heat generated can be increased, and productivity is approximately 27% higher than in conventional operations, and both the oxygen and coal consumption rates are significantly lower.
また、粉炭の吹込みにより、炉内のガス温度が約１７３
０℃であることから、耐火煉瓦の損耗速度も、従来法の
低二次燃焼率の操業とほぼ同じ程度まで低減でき、煉瓦
原単位も２．０ｋｇ／Ｔと少なく煉瓦寿命も問題なかっ
た。In addition, due to the injection of powdered coal, the gas temperature inside the furnace increased to approximately 173℃.
Since the temperature was 0°C, the wear rate of the refractory bricks could be reduced to almost the same level as in the conventional low secondary combustion rate operation, and the brick unit consumption was as low as 2.0 kg/T, so there was no problem with the life of the bricks.
次に粉炭に代えて粉鉱石を用いて操業した。粉鉱石は粉
体供給タンク６ｂから吹込みノズル７を介して炉口の壁
より１００ｍｍの部位に吹込んだ。Next, it was operated using powdered ore instead of powdered coal. The fine ore was blown from the powder supply tank 6b through the blowing nozzle 7 into a region 100 mm from the wall of the furnace mouth.
粉鉱石としては通常シンターフィードと称される焼結用
粉鉱石を用いた。この操業時に炉内壁面より２００ ｍ
ｍのところのガス温度を測定したところ表−８に示す通
り１１５℃の温度低下が認められた。As the fine ore, a fine ore for sintering commonly called sinter feed was used. During this operation, 200 m from the furnace inner wall surface.
When the gas temperature at point m was measured, a decrease in temperature of 115°C was observed as shown in Table 8.
また発生ガス中の飛散鉱石を採取して分析した結果、約
６％還元していることも判明し、炉壁への熱負荷を低減
できることが確認された。In addition, as a result of collecting and analyzing the scattered ore in the generated gas, it was found that it was reduced by about 6%, confirming that the heat load on the furnace wall can be reduced.
（発明の効果）
本発明による溶融還元操業において、粉炭を吹込む方法
では、発生ガス冷却、脱炭酸、ガスの再加熱といった複
雑で膨大な設備を必要とせず、排ガスダクト内でガス改
質することにより、設備費と運転費ともに安価な高予備
還元、かつ、高二次燃焼の操業が可能となる。(Effect of the invention) In the smelting reduction operation according to the present invention, the method of injecting pulverized coal does not require complicated and enormous equipment for cooling generated gas, decarboxylation, and reheating the gas, and the gas is reformed in the exhaust gas duct. This makes it possible to operate with high preliminary reduction and high secondary combustion with low equipment costs and operating costs.
また、従来法の溶融還元炉から発生するガスを予備還元
炉に熱いままで直結する方法においてはどうしても解決
できなかった溶融還元炉での高二次燃焼による炉内の発
生熱量の増加と、予備還元の比率を高めて、溶融還元炉
の消費熱量を低減することの両立が可能となり、石炭原
単位もコークス炉−高炉法と同等まで低減できた。In addition, the increase in the amount of heat generated in the furnace due to high secondary combustion in the smelting reduction furnace, which could not be solved with the conventional method of directly connecting the gas generated from the smelting reduction furnace to the pre-reduction furnace while still hot, and the pre-reduction It became possible to simultaneously reduce the amount of heat consumed by the smelting reduction furnace by increasing the ratio of
溶融還元法においては、コークス炉−高炉法では使用で
きない安価な一般炭を使用できることと、鉱石及び石炭
の事前処理が不要なことから、石炭原単位を高炉法と同
等とすることにより、溶銑の製造費用は高炉法に比較し
て１０〜２０％程度も低減することができた。In the smelting reduction method, cheap steam coal that cannot be used in the coke oven-blast furnace method can be used, and pre-treatment of ore and coal is not required. The manufacturing cost was able to be reduced by about 10 to 20% compared to the blast furnace method.
また、溶融還元炉のガス温度を低下させたことから、煉
瓦の寿命も延長されて、煉瓦費用が安価になったばかり
でなく、炉の補修周期も延長され、従来法２の操業では
連続Ｉ５日程度しか操業を続行できなかったが、本発明
により２ケ月以上の連続操業も可能となり、設備の稼働
率が２０％以上も向上し、また、修繕費用も低減された
。In addition, by lowering the gas temperature in the smelting reduction furnace, the life of the bricks is extended, which not only reduces the cost of the bricks, but also extends the furnace repair cycle. However, the present invention has made it possible to continue operation for more than two months, improving the operating rate of the equipment by more than 20% and reducing repair costs.
更に粉鉱石を吹込む方法においても、炉壁周囲のガス温
度を低下させることができ、この耐火煉瓦の耐用寿命を
大幅に延ばすことができた。加えて粉鉱石を部分的に還
元できたことから石炭及び酸素の原単位が向上した。Furthermore, with the method of injecting fine ore, the gas temperature around the furnace wall could be lowered, and the service life of the refractory bricks could be significantly extended. In addition, because the fine ore could be partially reduced, the unit consumption of coal and oxygen improved.
第１図は本発明の全体説明図、第２図は着熱効率と二次
燃焼率の図表、第３図は本発明の溶融還元炉の部分解析
図、第４図は本発明の溶融還元炉の部分説明図、第５図
（ａ） 、 （ｂ）及び（ｅ）は本発明の粉炭用バイブ
の模式図で０）は側面図、（０）は正面図、第６図は進
退可能な吹込みノズルの一実施例を示す構造図、第７図
は吹込みノズル近傍耐火煉瓦の冷却構造機構の一実施例
を示す断面図である。
代
理
人Figure 1 is an overall explanatory diagram of the present invention, Figure 2 is a chart of heat transfer efficiency and secondary combustion rate, Figure 3 is a partial analysis diagram of the smelting reduction furnace of the present invention, and Figure 4 is the smelting reduction furnace of the present invention. 5(a), (b) and (e) are schematic diagrams of the vibrator for pulverized coal of the present invention, 0) is a side view, (0) is a front view, and FIG. 6 is a vibrator that can move forward and backward. FIG. 7 is a structural diagram showing one embodiment of the blowing nozzle, and FIG. 7 is a sectional view showing one embodiment of the cooling structure mechanism for the refractory bricks near the blowing nozzle. agent
Claims (1)
ら吹付ける鉄浴式の溶融還元炉において、上吹酸素の吹
錬時に、炉壁から中心方向に１／３以内の炉内上昇ガス
流に粉状の原料を吹込むことを特徴とする金属の溶融還
元法。 ２、吹込む粉状の原料が粉炭であることを特徴とする請
求項１項記載の金属の溶融還元法。 ３、吹込む粉状の原料が粉鉱石であることを特徴とする
請求項１項記載の金属の溶融還元法。 ４、吹込む石炭の粒（Ｄｐ）を２ｍｍ、もしくは次式に
より求まる値の何れか小さいもの以下とすることを特徴
とする請求項１項又は２項記載の金属の溶融還元法。 Ｄｐ＝０．４７・Ｖ＾２＾／＾３（ｍｍ） （Ｖ：排ガスダクト内ガス流速（ｍ／ｓｅｃ））５、溶
融還元炉から得られた発生ガスを常温まで冷却すること
なしに鉱石の予備還元炉に導くことを特徴とする請求項
１項、２項及び４項記載の金属の溶融還元法。 ６、粉状原料の吹込みノズルが炉壁上部に進退可能に装
着され、前記ノズル周辺の耐火煉瓦が冷却構造機構を備
えていることを特徴とする請求項１項〜５項記載の溶融
還元炉。 ７、ノズル周辺耐火煉瓦の冷却構造機構が、炉内側に開
口面を有する複数個の冷却媒体噴出管を埋設して構成さ
れたことを特徴とする請求項６項記載の溶融還元炉。[Claims] 1. In an iron bath-type smelting reduction furnace that uses ore and coal and blows at least a portion of oxygen from above, during top-blown oxygen blowing, 1/3 of the furnace wall is blown toward the center. A metal smelting reduction method characterized by injecting powdered raw materials into the rising gas flow inside the furnace. 2. The method for smelting and reducing metals according to claim 1, wherein the powdered raw material to be blown in is powdered coal. 3. The metal smelting reduction method according to claim 1, wherein the powdered raw material to be blown into is powdered ore. 4. The metal smelting reduction method according to claim 1 or 2, characterized in that the injected coal particles (Dp) are equal to or smaller than 2 mm or a value determined by the following formula, whichever is smaller. Dp=0.47・V^2^/^3 (mm) (V: gas flow velocity in exhaust gas duct (m/sec)) 5. The method for melting and reducing metals according to claim 1, 2, and 4, wherein the metal is introduced into a preliminary reduction furnace. 6. The smelting reduction according to any one of claims 1 to 5, characterized in that a blowing nozzle for the powdered raw material is attached to the upper part of the furnace wall so as to be movable back and forth, and the refractory bricks around the nozzle are provided with a cooling structure mechanism. Furnace. 7. The smelting reduction furnace according to claim 6, wherein the cooling structure for the refractory bricks around the nozzle is constructed by embedding a plurality of cooling medium ejection pipes each having an opening surface inside the furnace.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1333262A JP2768775B2 (en) | 1989-09-04 | 1989-12-22 | Metal smelting reduction method and smelting reduction furnace |
| US07/569,282 US5135572A (en) | 1989-08-29 | 1990-08-17 | Method for in-bath smelting reduction of metals |
| EP90116468A EP0419868B1 (en) | 1989-08-29 | 1990-08-28 | Method of in-bath smelting reduction of metals and in-bath smelting reduction furnace |
| DE69014057T DE69014057T2 (en) | 1989-08-29 | 1990-08-28 | Metal smelting reduction process and smelting reduction furnace. |
| CA002024184A CA2024184A1 (en) | 1989-08-29 | 1990-08-28 | Method of in-bath smelting reduction of metals and in-bath smelting reduction furnace |
| AU61904/90A AU632161B2 (en) | 1989-08-29 | 1990-08-29 | Method of in-bath smelting reduction of metals and in-bath smelting reduction furnace |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22755389 | 1989-09-04 | ||
| JP1-227553 | 1989-09-04 | ||
| JP1333262A JP2768775B2 (en) | 1989-09-04 | 1989-12-22 | Metal smelting reduction method and smelting reduction furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03177513A true JPH03177513A (en) | 1991-08-01 |
| JP2768775B2 JP2768775B2 (en) | 1998-06-25 |
Family
ID=26527749
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1333262A Expired - Fee Related JP2768775B2 (en) | 1989-08-29 | 1989-12-22 | Metal smelting reduction method and smelting reduction furnace |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2768775B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015178930A (en) * | 2014-03-19 | 2015-10-08 | 株式会社神戸製鋼所 | Furnace refractory product life prediction method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63140014A (en) * | 1986-12-02 | 1988-06-11 | Nkk Corp | Smelting reduction refining device |
| JPH01147009A (en) * | 1987-11-30 | 1989-06-08 | Nkk Corp | Melting and reducing method |
| JPH01191719A (en) * | 1988-01-27 | 1989-08-01 | Nippon Steel Corp | Method for operating smelting reduction furnace |
-
1989
- 1989-12-22 JP JP1333262A patent/JP2768775B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63140014A (en) * | 1986-12-02 | 1988-06-11 | Nkk Corp | Smelting reduction refining device |
| JPH01147009A (en) * | 1987-11-30 | 1989-06-08 | Nkk Corp | Melting and reducing method |
| JPH01191719A (en) * | 1988-01-27 | 1989-08-01 | Nippon Steel Corp | Method for operating smelting reduction furnace |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015178930A (en) * | 2014-03-19 | 2015-10-08 | 株式会社神戸製鋼所 | Furnace refractory product life prediction method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2768775B2 (en) | 1998-06-25 |
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