JP3572645B2

JP3572645B2 - Raw material charging method for vertical smelting furnace

Info

Publication number: JP3572645B2
Application number: JP29546493A
Authority: JP
Inventors: 昌治宮川; 幹治武田; 宏板谷; 崇牛島; 精祐兒子
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 1993-11-25
Filing date: 1993-11-25
Publication date: 2004-10-06
Anticipated expiration: 2019-10-06
Also published as: JPH07146080A

Description

【０００１】
【産業上の利用分野】
本発明は、竪型炉により溶融金属を製造する製錬技術に関し、とくに竪型製錬炉内への原料装入方法に関する。
【０００２】
【従来の技術】
竪型製錬炉の一つである高炉では、炉内が固・気・液体の向流する高温移動層になっており、その操業を安定に維持することを目的として、原料装入時には原料の装入物分布制御が行われている。
この場合の装入物分布制御とは、高炉内に装入される鉱石，焼結鉱，コークスなどの装入原燃料（以下原料と呼ぶ）の炉半径方向や炉円周方向での
（１）鉱石層厚やコークス層厚、あるいは鉱石層厚とコークス層厚の比、
（２）鉱石粒径やコークス粒径、あるいは鉱石粒径とコークス粒径の比、
を目標値に制御することであり、
１）炉円周方向での原料の堆積分布については、上記（１）、（２）の値が炉円周方向で均一に分布することが望ましく、
２）炉半径方向での原料の堆積分布については、（１）と（２）の値から決定される通気抵抗分布を適正に制御することが肝要である。
【０００３】
そして、ベル式装入装置をもつ高炉では所謂ムーバブル・アーマを用いて、また、ベルレス式装入装置をもつ高炉では旋回シュートの傾動角あるいは複数の傾動角を組合せることによって、原料の装入物分布制御が行われている。
一方、高炉以外の竪型製錬炉では、高炉と異なる炭材を用いるため炉頂から装入する原料の落下強度が弱く、上記ムーバブル・アーマや旋回シュートを使用した場合には、炉頂で原料が粉化して
ａ）ダストとしての飛散が多くなる、
ｂ）竪型精錬炉内の固体移動層の降下異常の原因となり、安定な操業ができない、
ｃ）炉頂温度が高くなった場合には、上記ムーバブル・アーマやベルレス式炉頂装入装置は使えない
等の理由で、炉頂からの原料装入を炉頂に設けた単数あるいは複数本数の筒もしくは管（以下、このような筒，管を合わせて装入管と称する）から行うことが試みられている。
【０００４】
たとえば、ＩｒｏｎＳｔｅｅｌＥｎｇ．，４５（１９６８）第１９７〜２０１頁に開示され、また、第３版鉄鋼便覧ＩＩ製銑・製鋼（日本鉄鋼協会編；昭和５４年発行〔丸善〕）第３３３頁にも引用されている還元鉄の製造法（Ｍｉｄｒｅｘ法）では、炉頂ホッパ下部の原料排出口から炉頂全域に渡って多岐に分岐した装入管を用いた原料装入装置が配設されている。
【０００５】
しかしながら、この方法では、炉頂ホッパ排出口から供給される広い粒度分布をもった原料を、炉頂半径方向に所望する粒度分布を持たせることはできない。すなわち、上記方法では、実質上、炉頂で原料粒度分布の半径方向制御は不可能であり、その結果、該竪型製錬炉内の半径方向ガス流れは極端な炉壁流となり、炉壁の熱負荷が多くなり、耐火物の損耗が多くなるとともに、熱損失も多くなり、燃料比が高く、不経済な操業となる。
【０００６】
また、ＮｉｐｐｏｎＳｔｅｅｌＴｅｃｈｎｉｃａｌＲｅｐｏｒｔ，Ｎｏ．１２（１９７８）Ｄｅｃ．に開示された還元鉄の製造法（新日鉄法）では、炉頂に配設された装入管は、竪型製錬炉の軸芯に一致して配設された１本の装入管である。そのため、装入管下端からの粒度分布をもった原料装入物の炉壁に向かう降下流れは、装入前の粒度分布をもった炉頂粒子堆積群が１種のスクリーン作用をするので、新規に装入したより小さな粒子は装入前のより大きな堆積粒子群の間を通過して下に落ちるため、装入管直下の中心位置で細粒が最も多くなり、炉壁部で粗粒の粒子が最も多くなる粒度分布となる。その結果、該竪型製錬炉内の半径方向ガス流れも極端な炉壁流となり、炉壁の熱負荷が多くなり、耐火物の損耗が多くなるとともに、熱損失も多くなり、燃料比が高く、不経済な操業となる。
【０００７】
さらに、特開昭５９−１４３００９に開示された、粉状原料からの溶融金属製造法に用いられた装入装置は、竪型製錬炉内に装入するのは炭材のみであるため、還元鉄製造のための竪型炉よりは炉頂温度が上昇し、場合によっては１０００℃以上の高温となる場合もあり、装入管方式の原料装入装置が必須であった。
しかしながら、この場合においても上記と同様、１本の装入管であり、該竪型炉内の半径方向ガス流れは炉壁流となり、炉壁の熱負荷が多くなり、耐火物の損耗が多くなるとともに、熱損失も多くなり、燃料比が高くなり不経済な操業となった。
【０００８】
【発明が解決しようとする課題】
本発明は、かかる事情を鑑みてなされたもので、還元鉄の製造や粉状鉱石からの溶融金属製造に使われる竪型製錬炉において、炉頂ではムーバブル・アーマや旋回シュートを用いずに、炉頂で装入原料の半径方向での粒度分布を制御できる原料装入方法の提供を目的とする。その結果、本発明は、最終的に該竪型製錬炉内の半径方向ガス流れを中心流から炉壁流まで自由に制御でき、極端な炉壁流に伴う炉壁の熱負荷の増大、炉壁耐火物の損耗の増大、炉壁熱負荷の増大、燃料比の増大等を避け、且つ安定した竪型製錬炉の操業を維持することを狙いにしている。
【０００９】
【課題を解決するための手段】
発明者は、上記目的を達成するために、多数の実験、研究を繰り返し、本発明を完成させた。すなわち、本発明は、竪型製錬炉の炉上方に設けた均排圧ホッパ、装入ホッパ及び装入管を経て炉内へ原料を装入するに際し、該装入ホッパ内に堆積する原料を、該原料の半径方向粒度偏析が該竪型製錬炉炉頂部での原料の半径方向粒度偏析とほぼ同じになるよう調整し、複数の装入管を経て炉内へ装入することを特徴とする竪型製錬炉の原料装入方法である。その際、好ましくは装入ホッパ内に堆積する原料の半径方向粒度偏析を装入ホッパ内に配設したベル、ベルとベルカップの組み合わせ、あるいは旋回シュートにより調整することを特徴とする竪型製錬炉の原料装入方法である。また、実際に際して、本発明は、竪型製錬炉が、炉内に炭素系固体還元剤の充填層が形成され、該充填層に高温空気や粉体原料を吹込む上下少なくとも２段に設けられたそれぞれ複数の羽口を有する炉であり、装入原料が炭材であることを特徴とする請求項１記載の竪型製錬炉の原料装入方法である。
【００１０】
【作用】
本発明では、竪型製錬炉に原料を装入するに際し、炉上方に設けた装入ホッパ内に堆積する原料を半径方向でムーバブル・アーマ、旋回シュート又は他の手段を用いて粒度偏析させ、装入管を経て炉頂に装入された場合には、そのままの偏析状態を維持して炉内へ該原料を装入できるようにしたので、炉内で原料の半径方向の粒度偏析が得られるようになる。また、本発明を炭素系固体充填層を形成し、該充填層に高温空気や粉体原料を吹込む上下２段に設けた羽口を有する竪型製錬炉に適用しても、上記と同じ効果が得られる。
【００１１】
その結果、操業者が炉内のガス流れを「中心流を抑制し、炉壁流を促進」したい時は、装入ホッパ内の炉壁側に粗粒コークスを分布させ、装入ホッパの炉中心側には細粒コークスを分布させることで、その目的を達成できる。逆に、炉内のガス流れを「中心流を促進し、炉壁流を抑制したい」ときは、装入ホッパ内の炉壁側に細粒コークスを分布させ、装入管ホッパの炉中心側には粗粒コークスを分布させることで良い。
【００１２】
以下、図１〜７に基づき、本発明に至る経緯と内容を説明する。
発明者らは、図１に示すような本発明に係る原料装入方法の概念で模型装置を製作し、炉中心軸に対して同心円上に配設され、かつ重力作用により、原料をその炉頂部に降下・充填させる４本の鉛直原料装入管を用いた原料の装入実験を行った。その実験では、
（Ａ）装入ホッパに装入した原料の半径方向の粒径分布と、装入管を介して竪型製錬炉の炉頂に実現される原料の半径方向の粒径分布との関係、
（Ｂ）（Ａ）の関係に対する装入物降下速度の影響、
（Ｃ）装入管構造や、装入ホッパの構造についての好ましい条件、等に焦点をあて、広範かつ網羅的な検討がなされた。
【００１３】
まず、図４は、本発明に係る竪型製錬炉の概略を示す図であり、上記模型実験は実際の炉に対して縮尺１／７．５の冷間模型（高温で還元をせず、原料の装入のみ）で行った。
装入コンベア１から装入された原料は、レシービングシュート２を経由して、均排圧ホッパ３に一時貯えられる。均排圧ホッパへの原料の装入を完了した後、レシービングシュート２の下端に設けられた上部シール弁４を閉じ、均排圧ホッパ３内部と装入ホッパ５内部の圧力が等しくなるように均排圧ホッパ３内部を加圧する。ついで、下部シール弁６、ゲート弁７の順で開放し、均排圧ホッパ３に一時貯えられた装入炭材を装入ホッパ５に排出する。ここでゲート弁７の開口部の大きさは、装入スケジュールで決められた時間内に原料の排出が完了するように調整できることが望ましい。均排圧ホッパ３から装入ホッパ５への原料の排出完了後、ゲート弁７、下部シール弁６の順で閉じる。装入ホッパ５に堆積したコークスあるいは石炭などの装入原料は、炉本体８での酸素あるいは二酸化炭素などとの反応によって消費されるので、その消費量に応じて装入ホッパ５下端に設けられた装入管９内を降下して装入管９先端から炉内に供給される（模型装置では、炉本体の下に設けた電磁フィーダーで炉内の原料を抜き出して消費量とする）。装入ホッパ５内には常に所定量の原料を堆積させることとし、装入ホッパ５内の原料量があらかじめ設定した下限値にいたった時に、再度、原料装入操作を繰り返す。
【００１４】
以下、上記（Ａ）〜（Ｃ）に記した広範な検討で行った実験の条件及び結果の一例を、原料がコークスである場合について述べる。
Ｉ．一般的な実験条件
（ａ）実験で用いたコークスは事前に乾燥−破砕−篩い分けを行ったもので、実操業で使用しているコークスに対して、できるだけ固体流れの相似を満たすように、調和平均径で２．５ｍｍになるよう粒度別に篩い分けたコークス試料を配合した。
（ｂ）１チャージ当たりのコークス重量は３．２ｋｇとし、これは実機では１３５０ｋｇに相当する。
（ｃ）実操業でのコークスの水分量は天候に大きく左右されるが、模型実験ではコークスの水分は特に調整せず、乾燥したままで用いた。
（ｄ）この場合、該コークスの諸特性を測定したところ、コークス付着水分量は１％以下であり、嵩密度は５．３ｇ／ｃｍ^３、安息角は３６°であった。
（ｅ）着色したコークスをトレーサとして用いて、「装入ホッパ〜装入管〜炉内」での装入炭材の降下状況を調べた。
（ｆ）この場合、図５に示すように、装入ホッパの底面（フラット部）の上端までコークスを充填し、次に装入ホッパ内に２枚の薄鉄板製円筒１０を同心円状に置いて装入ホッパ内部を３つの領域に分割し、領域毎に色の異なるコークスを入れ、装入ホッパの上端までコークスで満たした。
（ｇ）炉本体の下に設けた電磁フィーダ（図示せず）で炉内のコークスを抜き出し、炉内のコークスを連続的に降下させると、装入ホッパ内の試料は装入管を経由して降下し、装入管の下端に到って、炉内に装入される。装入ホッパ内のコークス試料の減少に対応して、同心円状の３つの領域の各々にすでに装入してあるコークスと同じ色のコークスを追加した。
（ｈ）実験では、実機の炭材２０チャージ分に相当する６４ｋｇのコークスを炉内から抜き出した。抜き出し時間はおおよそ８０分であった。
（ｉ）試料抜き出し終了後、炉内の堆積面表面あるいは炉内の垂直断面でコークスの分布状況を観察した。断面観察の場合は、実験前に炉内の観察面の位置の直径方向に透明塩ビ製の板を垂直に固定し、実験後に炉内を半分に仕切っている塩ビ板の片側半分の試料を掘り出し、半裁断面を観察した。
ＩＩ．実験結果
実験後の炉内表面の原料の分布状態は、装入ホッパの壁側に堆積したコークスは炉頂では炉壁部に堆積し、装入ホッパの中心部に堆積したコークスは炉頂では中心部に堆積していることが明らかになった。この事実と装入管直下部の炉内の垂直断面での原料の分布状態とを合わせると、装入ホッパから排出されたコークスが装入管を経由して降下する時、装入ホッパの壁側に分布したコークスは装入管内の外側を降下し、装入ホッパの中心部に分布したコークスは装入管内の内側を降下し、コークスが炉内に供給される際に、装入管内の外側を降下してきたコークスは装入管先端の外側の部分から炉壁側に向けて排出され、これに対して、装入管内の内側を降下してきたコークスは装入管先端の炉中心側の部分から炉中心部に向けて排出される。これを図示すると図６のようになる。なお、図６中の記号９−１、９−２等は装入管を示している。
【００１５】
また、図７に示すように、コークス排出速度を変化させても、装入ホッパ内の壁側に堆積したコークスの装入ホッパからの排出速度と、装入ホッパの中心部に堆積したコークスの装入ホッパからの排出速度の比率は大きくは変化せず、やはり、装入ホッパの壁側に堆積したコークスは炉内の炉壁に堆積し、装入ホッパの中心部に堆積したコークスは炉内の中心部に堆積する。
【００１６】
ここで、「従来の技術」の項でも述べたように、装入管が１本の場合は中央に設置すると、図３（ａ）に示したように、炉中心部に細粒が分布し、かつ炉壁部に粗粒が分布して操業上好ましくない。中心からずれた位置に装入管を設置することで細粒の分布を炉中心からずらすことはできても、炭材の粒度分布の対称の中心が炉の中心軸と一致せず、炉内の炭材の粒度分布の対称性が乱れ、操業に対する外乱要因になるのみと推定された。装入管２本の場合も、炭材の粒度分布の対称性は改善効果は少なく、装入管を用いた竪型炉内への炭材の供給は、炭材の粒度分布の対称性の観点からは、装入管の本数が多い方が好ましいといえる。しかし、無制限に多くすることは設備の取り合いからできないから、少なくとも３本以上の装入管から構成することが適当である。さらに、複数本の装入管を装入ホッパに同心円上に配置することで、炭材の粒度分布の対称性を乱さず、目標装入物分布の確保を効果的に実施できる。
【００１７】
装入管４本を用い、装入ホッパ内の半径方向での堆積コークスの粒度分布を制御しない場合の各サンプリング点での平均粒径値を全体の平均粒径値で除した無次元粒径の炉直径方向の分布、並びに装入ホッパーの半径方向での堆積コークスの粒径分布を制御した場合の分布を図３（ｂ）及び（ｃ）に示した。なお、図２はこの実験での装入管位置を方位で示す図である。図３（ｂ）よりあきらかなように、均排圧ホッパに制御板を入れずに装入管を４本用いても、炉中心部と炉壁部に粗粒が堆積する粒度分布が形成されている。このことは、炉壁部に堆積した粗粒によって炉内の高温のガスが炉壁部に優先的に流れる（炉壁流になる）ことになるから、耐火物の保護、経済性の観点から、この粒度分布は一般的に好ましくない。
【００１８】
一方、均排圧ホッパに制御板を入れて装入ホッパ内の粒度分布を制御した場合は、炉中心部のコークス粒径を大きく、炉壁部のコークス粒径を小さくできることから炉内でのガス流分布を操業上好ましい状態にできると推定される。その際、均排圧ホッパ内に設ける原料の半径方向粒度偏析の制御装置としては、制御板、回転分配器等、どのようなものでも良いが、特に制御板の場合には、円形、正方形、あるいは円錐形状であってもかまわない。ただし、炉の中心軸と制御板の重心を一致させ、炉の中心軸に対して対称形であることが好ましい。また、装入ホッパ内にベル、ベルとベルカップの組み合わせあるいは旋回シュートを配設して原料の半径方向粒度偏析の制御を行っても良い。
【００１９】
さらに、上記の結果は、原料がコークスでなく、塊鉱石、焼結鉱、他の炭材でも同様の傾向・効果が得られ、粒径分布を持つ原料装入物の炉頂装入時に共通する粒度偏析現象であることが多くの実験から明らかになった。
装入ホッパの形状は、円筒に４個のコーン部が配置され、各ホッパの先端に装入管が取り付けられており、この装入管を経由して炉内にコークスが供給される形式のものを用いた。あるいは装入ホッパの形状として、ホッパ中心部に円錐台形状の突起を有し、円錐台形状の突起とホッパの外壁との間で漏斗状の空間を形成し、漏斗状の空間の底部に装入管を配置したものであってもよい。また、装入管自体の構造としては、円筒状でも良いが、管内でのブリッジの発生を防止する意味から若干末拡がりのテーパーを付けた円筒管が好ましい。その材質は、炉頂ガスと反応しないもので、特に、該竪型製錬炉の炉頂温度が上昇する可能性のある場合には、耐熱合金製又はセラミックスや耐火物製のものが好ましい。
【００２０】
発明者は、以上のような模型実験で得た新規な知見にもとづいて、装入ホッパ内の半径方向のコークス粒度分布を制御し、その粒度分布を維持するように多数の装入管を通して原料を落下させることによって、炉内半径方向のコークス粒度分布を制御技術を完成させたのである。
装入ホッパ内でのコークスの粒度分布を制御するには、装入ホッパ内での炭材の堆積状態を調整する方策が有効であり、具体的には、装入ホッパ下端に有する複数本の装入管を装入ホッパの中心軸あるいは製錬炉の中心軸を中心とする同心円上に配置するとともに、図１に示すように均排圧ホッパ内に制御板を設けて、装入ホッパに炭材を供給する均排圧ホッパ内での炭材堆積時と、均排圧ホッパからの炭材排出時の炭材の運動を制御すればよいとの結論に達したのである。
【００２１】
【実施例】
内容積１４０ｍ^３の竪型製錬炉８の炉頂部に、該製錬炉の中心軸に対して同心円上９０°の等間隔に配設され、かつ重力作用により、原料１１を製錬炉８炉頂部に降下・充填させる４本の鉛直原料装入管９と、該装入管９に連結された装入ホッパ５、該装入ホッパ５に原料１１の粒度偏析を半径方向につける手段及び該原料１１の半径方向の粒度偏析を検知する手段を有する均排圧ホッパ３からなる原料装入装置を用いて炭材を炉内に装入し、装入物の填充状態を調査をした。
【００２２】
均排圧ホッパ３は、内径２２００ｍｍ、排出部直径５００ｍｍ、制御板１２の径は７５０ｍｍで、かつその取付け位置は均排圧ホッパ３の原料１１排出部下端から上方に８００ｍｍの位置である。この時、制御板１２と均排圧ホッパ３の間隔は２５０ｍｍであった。炭材の平均粒径は２５ｍｍであったが、制御板１２と均排圧ホッパ３間での炭材の詰まりの問題はおこらなかった。
【００２３】
装入ベルトコンベア１から装入されたコークス１１を、レシービングシュート２を経由して、均排圧ホッパ３に一時貯え、レシービングシュート２の下端に設けられた上部シール弁４を閉じて、均排圧ホッパ３内部と装入ホッパ５内部の圧力が等しくする操作を行った。ついで、下部シール弁６、ゲート弁７の順で開放し、均排圧ホッパ３に一時貯蔵したコークス１１を装入ホッパ５に排出した。ここでゲート弁７の開口部の形状は３００ｍｍの正方形であり、原料１１の排出平均時間は１０１．５秒（実験回数ｎ＝１０）であった。均排圧ホッパ３から装入ホッパ５への原料の排出完了後、ゲート弁７、下部シール弁６の順で閉じた。
【００２４】
この実験結果をまとめると先に模型実験で得た図３（ｂ）〜（ｃ）と同様になり、単純に４本足装入管９から原料１１を炉内に供給したベース（図３（ｂ））と比較して、均排圧ホッパ３内の制御板１２を設けた場合は（図３（ａ））、炉壁部の粗粒の抑制に効果が認められた。すなわち、均排圧ホッパ３内の制御板１２の有無によって竪型製錬炉８内の半径方向の炭材粒径分布の制御が可能であった。
【００２５】
さらに、装入ホッパ５に原料を供給する均排圧ホッパ３に配設した装入管ホッパ５内の原料粒度偏析を半径方向に制御する制御板１２を具体的に作用させるにあたって、竪型製錬炉８内炉頂に設けた観察用カメラの撮像結果から該原料１１の半径方向の粒度偏析状況を求めた。これと予め設定した竪型製錬炉炉頂部での原料１１の半径方向粒度分布の目標値を比較するとほぼ一致していた。この装入状態で操業を行った場合、竪型製錬炉８の高さ方向３ケ所、円周方向４５°ピッチ８ケ所の計２４ケ所での炉壁耐火物の損耗速度は前者を基準として、１０％の低減効果があった。
【００２６】
また、均排圧ホッパ３に配設した制御板１２を作用させるにあたって、竪型製錬炉８の炉頂部直径方向に差し渡した水平ゾンデ（温度、ガス組成のセンサ）を用いて竪型製錬炉８の半径方向のガス組成分布とガス温度分布を検出し、これが目標とするガス組成、ガス温度分布のいづれかもしくは両者と一致するように制御すると更に効果的である。
【００２７】
本実施例においては、制御板１２が無い場合と比較して原料排出制御板１２が有る場合は、炉中心部の炭材の平均粒径を大きくでき、かつ炉壁部の炭材の平均粒径を抑制できる。すなわち、炉壁部のみに優先的にガスが流れる条件では炉壁に対する熱的な負荷が上昇し炉壁の損耗を早めることになるから、制御板１２を設置し炉壁部の炭材の平均粒径を抑制すればよい。逆に炉壁部にほとんどガスが流れない条件では、炉壁での付着物の形成が進むと、やがて炉壁から付着物が脱落し、安定操業に対する著しい阻害要因となるから、制御板１２を使用せず炉壁部の炭材の平均粒径を促進すればよい。
【００２８】
また、制御板１２の大きさ・取付け位置を変更することで装入ホッパ５内の炭材の堆積・排出状態を変化させることができ、ホッパ内の炭材粒度分布を制御し、ホッパの炉壁部に堆積したコークスは炉内の炉壁に堆積し、ホッパの中心部に堆積したコークスは炉内の中心部に堆積するから、炉内の炭材の粒度分布が制御できることはいうまでもない。
【００２９】
次に、上記実施例と同じ内容積１４０ｍ^３の竪型炉を用いて、別の填充調査を行った。その際、図８に示すように、装入ホッパ５には、底面直径２４００ｍｍで高さ１２００ｍｍの円錐形状の耐摩耗鋳鋼製のベル１３を取付けた。ベル１３下端と装入ホッパ５の底面フラット部１４との距離を１０００ｍｍとして、ベル１３の中心軸と竪型製錬炉８の中心軸が一致するように、ベル１３を固定した。装入ホッパ５の内径は３３００ｍｍ，ベル１３底面の直径は２４００ｍｍであり、装入管９の内壁とベル１３との間のクリアランスは４５０ｍｍであったが、均排圧ホッパ３から排出した炭材１１は、特に問題なく装入ホッパ５内に堆積し、かつ装入管９を降下した。装入管の本数はこの場合も４本であって、それらは竪型製錬炉の中心軸に対して同心円上に配置されている。但し、図８（ｂ）に示した装入ホッパ５内にベル１３のみを設けた条件では、均排圧ホッパ３からの炭材１１の落下具合によって、ベル１３の特定の斜面からの炭材１１の落下が優先し、竪型製錬炉８内円周方向で炭材１１の堆積状態が不均一になることがあった。
【００３０】
装入ベルトコンベア１から装入された炭材１１を、レシービングシュート２を経由して、均排圧ホッパ３に一時貯えた。レシービングシュート２の下端に設けられた上部シール弁４を閉じて、均排圧ホッパ３内部と装入ホッパ５内部の圧力を等しくする操作を行った。ついで、下部シール弁６、ゲート弁７の順で開放し、均排圧ホッパ３に一時貯蔵した炭材１１を装入ホッパ５に排出した。ここで、ゲート弁７の開口部の径は３００ｍｍであり、炭材１１の排出平均時間は１０３．７秒（実験回数ｎ＝１０）であった。均排圧ホッパ３から装入ホッパ５への炭材１１の排出完了後、ゲート弁７、下部シール弁６の順で閉じる。図３（ｄ）はこの時の実験結果をまとめたものであり、本発明者の推論に違わず、単純に４本足装入管から炭材１１を炉内に供給したベース条件と比較して、装入ホッパ５内の炭材１１の堆積形状を制御することで、炉中心部の平均粒径の増加と炉壁部の粗粒の抑制の効果が認められた。
【００３１】
装入ホッパ５内にベル１３を設置するだけの図８（ｂ）のような場合は、均排圧ホッパ３からの炭材１１の落下の具合によって、炭材１１がベル１３の特定の斜面から落下し、炉内円周方向で炭材１１の堆積量が不均一になることがある。これに対して、図８（ｃ）に示すように、装入ホッパ５内に設置したベル１３にベルカップ１５を組み合わせ、一度ベル１３とベルカップ１５の間に炭材１１を堆積させた後に、ベル１３を降下することでベル１３とベルカップ１５の間隙から炭材１１が落下するようにベルカップ１５を配置すると（図９参照）、ベル１３上での炭材１１の偏流に起因した円周方向の炭材落下量のばらつきを小さくできた。この場合は、装入ホッパ５内に設置するベル１３あるいはベルカップ１５を可動構造にする必要があり、例えば高炉で見られるように上下に駆動できる構造のベルにする。
【００３２】
装入ホッパ５内にベル１３を設置する、あるいはベル１３とベルカップ１５を設置した上記実施例に対して、図８（ｄ）に示すように、炉半径方向に可動するムーバブル・アーマ１６を円周方向に配置した場合も調査した。そこでは、炭材１１がベル１３先端から炉内に落下する際、図９に示すように、炉半径方向でその位置を調整したムーバブル・アーマ１６に炭材１１がぶつかった後に、竪型製錬炉８内に落下するようになるので、炭材１１の炉半径方向での落下位置は容易に制御することができた。さらに、装入ホッパ５内での炭材１１の堆積形状の調節に図８（ｅ）に示すように、装入ホッパ５内に傾動旋回自在のベルレスシュート１７を設置すると、竪型製錬炉８内に落下する炭材１１の落下位置は、図８（ｄ）の場合と比較してみてもさらに精度の良い制御が可能となった。ベル、ベルカップさらにムーバブル・アーマあるいはベルレスシュートを用いたこの実施例においては、これら装置は炉頂部ではなく、装入ホッパ内に配置され、炉内とは装入管によって連絡するものの高温のガスが炉頂部から装入ホッパに入らないので、設備上の耐使用温度に関する問題はない。
【００３３】
【発明の効果】
竪型製錬炉において装入管方式で行う原料装入は、高炉のようにムーバブル・アーマや旋回シュートを持たないので、設備構造が比較的簡単であり、製錬炉における設備費を相対的に安価なものにでき、且つ設備のメンテも容易である。本発明では、かかる利点を活かしながら、従来できなかった炭材の粒度偏析分布を実現したことになる。
【００３４】
その結果、高温度にも耐え、炉壁部のみに優先的にガスが流れることを防いで炉壁に対する熱的な負荷の上昇を低減し、炉壁損耗の抑制が期待できる。
【図面の簡単な説明】
【図１】本発明に係る原料装入方法の概念を示す模式図である。
【図２】モデル実験での装入管位置を方位で示す図である。
【図３】図１に示した装置を用いて本発明を実験した時の炉頂における炉半径方向の平均粒度分布（ｃ）（ｄ）、ならびに比較例（ａ），（ｂ）を示す図である。
【図４】竪型製錬炉の具体的な装置構成を示す図である。
【図５】模型実験の実施方法を示す図である。
【図６】模型実験による装入ホッパから炉内への原料降下状況の調査結果であり、（ａ）は装入ホッパ内の原料分布、（ｂ）は製錬炉内装入物の表面における原料分布を示す図である。
【図７】模型実験による装入ホッパからの原料排出速度の影響を調査した結果である。
【図８】本発明に係る原料装入方法の実施態様を示す図であり、（ａ）は従来例、（ｂ）は装入ホッパ内の堆積原料の粒度偏析を起こさせるためにベル、（ｃ）はベルとベルカップ、（ｄ）はベルとムーバブル・アーマ、（ｅ）はベルレス・シュートをそれぞれ用いた場合である。なお、図中の矢印は炭材の運動を示している。
【図９】ベルとベルカップ間から炭材が落下する様子を示し、（ｄ）の装置を用いての（ａ）はベルとベルとベルカップ間に炭材を堆積した状況、（ｂ）はムーバブル・アーマ使用なし、（ｃ）はムーバブル・アーマ使用時の炭材落下状況を示す図である。
【図１０】ベルレス・シュートを用いた装入ホッパ内での炭材堆積状況である。
【符号の説明】
１装入コンベア
２レシービングシュート
３均排圧ホッパ
４上部シール弁
５装入ホッパ
６下部シール弁
７ゲート弁
８炉本体（竪型精錬炉）
９装入管
１０薄い鉄板の仕切り
１１原料（コークス）
１２制御板
１３ベル
１４装入ホッパの底面フラット部
１５ベルカップ
１６ムーバブル・アーマ
１７ベルレス・シュート[0001]
[Industrial applications]
The present invention relates to a smelting technique for producing molten metal by a vertical furnace, and particularly to a method for charging raw materials into a vertical smelting furnace.To the lawRelated.
[0002]
[Prior art]
In a blast furnace, one of the vertical smelting furnaces, the inside of the furnace is a high-temperature moving bed in which solids, gas, and liquid flow in countercurrent. Is controlled.
In this case, the charge distribution control means the ore, sinter, coke, and other charged raw fuel (hereinafter referred to as “raw material”) charged in the blast furnace in the furnace radial direction or furnace circumferential direction.
(1) ore layer thickness, coke layer thickness, or ratio of ore layer to coke layer thickness,
(2) ore particle size or coke particle size, or ratio of ore particle size to coke particle size,
Is controlled to a target value,
1) Regarding the deposition distribution of the raw material in the furnace circumferential direction, it is desirable that the values of (1) and (2) are uniformly distributed in the furnace circumferential direction.
2) Regarding the deposition distribution of the raw material in the furnace radial direction, it is important to appropriately control the ventilation resistance distribution determined from the values of (1) and (2).
[0003]
In a blast furnace having a bell-type charging device, a so-called movable armor is used. In a blast furnace having a bell-less charging device, the tilting angle of a turning chute or a combination of a plurality of tilt angles is used to charge the raw material. Object distribution control is performed.
On the other hand, in vertical smelting furnaces other than blast furnaces, since the carbon material different from that of the blast furnace is used, the drop strength of the raw material charged from the furnace top is weak. The raw material is powdered
a) scattering as dust increases,
b) It causes abnormal lowering of the solid moving bed in the vertical smelting furnace, so that stable operation cannot be performed.
c) If the furnace top temperature becomes high, the above movable armor or bellless type furnace top charging device cannot be used.
For such reasons, it has been attempted to charge the raw material from the furnace top from one or more tubes or tubes provided on the furnace top (hereinafter, such tubes and tubes are collectively referred to as a charging tube). ing.
[0004]
For example, Iron Steel Eng. , 45 (1968) pp. 197-201, and also cited in Iron and Steel Handbook II, Iron and Steelmaking, Third Edition (edited by the Iron and Steel Institute of Japan; published in 1979 [Maruzen]), p. 333. In the iron production method (Midrex method), a raw material charging device using a charging pipe branched from the raw material discharge port at the lower part of the furnace top hopper to the entire furnace top is provided.
[0005]
However, in this method, the raw material having a wide particle size distribution supplied from the furnace top hopper outlet cannot have a desired particle size distribution in the furnace top radial direction. That is, in the above method, it is practically impossible to control the raw material particle size distribution in the radial direction at the furnace top, and as a result, the radial gas flow in the vertical smelting furnace becomes an extreme furnace wall flow, As a result, the heat load increases, the refractory wear increases, and the heat loss also increases, resulting in a high fuel ratio and uneconomical operation.
[0006]
Also, Nippon Steel Technical Report, No. 12 (1978) Dec. In the method for producing reduced iron (Nippon Steel) disclosed in the above, the charging pipe disposed on the furnace top is a single charging pipe disposed in line with the axis of the vertical smelting furnace. is there. Therefore, the descending flow of the raw material charge having the particle size distribution from the lower end of the charging pipe toward the furnace wall is performed because the furnace top particle accumulation group having the particle size distribution before the charging acts as one type of screen. The newly charged smaller particles pass between the larger sediment particles before charging and fall down, so the fines are the most at the center just below the charging pipe and the coarse particles are at the furnace wall. Has the largest particle size distribution. As a result, the gas flow in the radial direction in the vertical smelting furnace also becomes an extreme furnace wall flow, the heat load on the furnace wall increases, the refractory wear increases, the heat loss increases, and the fuel ratio increases. High and uneconomical operation.
[0007]
Furthermore, the charging apparatus used in the method for producing a molten metal from a powdery raw material disclosed in JP-A-59-143909 is because only the carbon material is charged into the vertical smelting furnace, The furnace top temperature is higher than that of a vertical furnace for the production of reduced iron, and in some cases the temperature may be as high as 1000 ° C. or more.
However, also in this case, as in the above case, a single charging pipe is used, and the gas flow in the radial direction in the vertical furnace becomes a furnace wall flow, the heat load on the furnace wall increases, and the wear of refractories increases. At the same time, heat loss increased, the fuel ratio increased, and the operation became uneconomical.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and in a vertical smelting furnace used for the production of reduced iron and the production of molten metal from powdery ore, without using a movable armor or a rotating chute at the furnace top. To provide a raw material charging method capable of controlling the particle size distribution in the radial direction of the raw material charged at the furnace top. SoAs a result, the present invention can finally control the radial gas flow in the vertical smelting furnace freely from the central flow to the furnace wall flow, increase the heat load on the furnace wall accompanying the extreme furnace wall flow, It aims at avoiding an increase in wear of the furnace wall refractories, an increase in the furnace wall heat load, an increase in the fuel ratio, and the like, and maintaining stable operation of the vertical smelting furnace.
[0009]
[Means for Solving the Problems]
The inventor repeated many experiments and studies to achieve the above object, and completed the present invention. That is, according to the present invention, when the raw material is charged into the furnace via the equalizing / discharge hopper, the charging hopper, and the charging pipe provided above the furnace of the vertical smelting furnace, the raw material deposited in the charging hopper is Is adjusted so that the radial grain size segregation of the raw material is substantially the same as the radial grain size segregation of the raw material at the top of the vertical smelting furnace, and charged into the furnace through a plurality of charging pipes. This is a method for charging raw materials for a vertical smelting furnace. At this time, preferably, the radial particle size segregation of the raw material deposited in the charging hopper is adjusted by a bell disposed in the charging hopper, a combination of a bell and a bell cup, or a swiveling chute. This is a method for charging raw materials for a smelting furnace. Further, in practice, the present invention relates to a vertical smelting furnace in which a packed bed of a carbon-based solid reducing agent is formed in a furnace, and the packed bed is provided with at least two upper and lower stages of blowing high-temperature air or powdered raw material into the packed bed. 2. The method for charging a vertical smelting furnace according to claim 1, wherein the furnace is a furnace having a plurality of tuyeres, and the charged raw material is a carbonaceous material..
[0010]
[Action]
In the present invention, when charging the raw material into the vertical smelting furnace, the raw material deposited in a charging hopper provided above the furnace is radially segregated using a movable armor, a rotating chute or other means. In the case where the raw material is charged into the furnace top via the charging pipe, the raw material can be charged into the furnace while maintaining the segregation state as it is, so that the radial particle size segregation of the raw material in the furnace is reduced. You will be able to obtain. Further, the present invention may be applied to a vertical smelting furnace having a tuyere provided in two upper and lower stages in which a carbon-based solid packed bed is formed and high-temperature air or powder material is blown into the packed bed. Same effect.
[0011]
As a result, when the operator wants to suppress the gas flow in the furnace and suppress the central flow and promote the furnace wall flow, the coarse coke is distributed on the furnace wall side in the charging hopper, and the furnace The purpose can be achieved by distributing fine-grain coke on the center side. Conversely, when the gas flow in the furnace is "to promote the central flow and suppress the furnace wall flow", fine-grain coke is distributed on the furnace wall side in the charging hopper, and the furnace center side of the charging pipe hopper. In this case, coarse coke may be distributed.
[0012]
Hereinafter, the process and contents leading to the present invention will be described with reference to FIGS.
The inventors manufactured a model apparatus based on the concept of the raw material charging method according to the present invention as shown in FIG. 1 and disposed on a concentric circle with respect to the central axis of the furnace, and the raw material was placed in the furnace by the action of gravity. A raw material charging experiment was performed using four vertical raw material charging pipes to be lowered and filled at the top. In that experiment,
(A) the relation between the radial particle size distribution of the raw material charged into the charging hopper and the radial particle size distribution of the raw material realized on the top of the vertical smelting furnace via the charging pipe;
(B) the effect of the charge descent speed on the relationship of (A);
(C) Extensive and exhaustive studies were made focusing on the preferred conditions for the charging pipe structure and the structure of the charging hopper.
[0013]
First, FIG. 4 is a view schematically showing a vertical smelting furnace according to the present invention. In the above-mentioned model experiment, a cold model of 1 / 7.5 scale (without reduction at high temperature) was used for an actual furnace. , Raw materials only).
The raw material charged from the charging conveyor 1 is temporarily stored in the equalizing / discharge hopper 3 via the receiving chute 2. After the charging of the raw material into the equalizing / discharge hopper is completed, the upper seal valve 4 provided at the lower end of the receiving chute 2 is closed so that the pressure inside the equalizing / discharge hopper 3 and the inside of the charging hopper 5 become equal. The inside of the equalizing pressure hopper 3 is pressurized. Then, the lower seal valve 6 and the gate valve 7 are opened in this order, and the charged carbon material temporarily stored in the equalizing pressure hopper 3 is discharged to the charging hopper 5. Here, it is desirable that the size of the opening of the gate valve 7 can be adjusted so that the discharge of the raw material is completed within the time determined by the charging schedule. After the discharge of the raw material from the equalizing pressure hopper 3 to the charging hopper 5 is completed, the gate valve 7 and the lower seal valve 6 are closed in this order. Charged material such as coke or coal deposited on the charging hopper 5 is consumed by reaction with oxygen or carbon dioxide in the furnace body 8, and is provided at the lower end of the charging hopper 5 in accordance with the consumption amount. Then, the raw material is supplied into the furnace from the tip of the charging pipe 9 by lowering the charged charging pipe 9 (in the model apparatus, the raw material in the furnace is extracted by an electromagnetic feeder provided below the furnace main body to be used as a consumption amount). A predetermined amount of raw material is always deposited in the charging hopper 5, and when the raw material amount in the charging hopper 5 reaches a preset lower limit, the raw material charging operation is repeated again.
[0014]
Hereinafter, examples of the conditions and results of the experiments performed in the extensive studies described in the above (A) to (C) will be described for the case where the raw material is coke.
I. General experimental conditions
(A) The coke used in the experiment was previously dried, crushed, and sieved. The coke used in the actual operation had a harmonic mean diameter of 2 to satisfy the similarity of the solid flow as much as possible. A coke sample sieved according to particle size was adjusted to 0.5 mm.
(B) The coke weight per charge is 3.2 kg, which corresponds to 1350 kg in the actual machine.
(C) The water content of the coke in the actual operation greatly depends on the weather, but in the model test, the water content of the coke was not particularly adjusted, and was used in a dry state.
(D) In this case, when various properties of the coke were measured, the amount of water adhering to the coke was 1% or less, and the bulk density was 5.3 g / cm.³  The angle of repose was 36 °.
(E) Using the colored coke as a tracer, the dropping state of the charged carbonaceous material in “the charging hopper—the charging pipe—the inside of the furnace” was examined.
(F) In this case, as shown in FIG. 5, coke is filled up to the upper end of the bottom surface (flat portion) of the charging hopper, and then two thin steel plate cylinders 10 are concentrically placed in the charging hopper. The inside of the charging hopper was divided into three regions, and coke of a different color was put into each region, and the upper end of the charging hopper was filled with coke.
(G) When coke in the furnace is extracted with an electromagnetic feeder (not shown) provided below the furnace body and the coke in the furnace is continuously lowered, the sample in the charging hopper passes through the charging pipe. To reach the lower end of the charging pipe and be charged into the furnace. Corresponding to the decrease in coke sample in the charging hopper, coke of the same color as coke already charged was added to each of the three concentric regions.
(H) In the experiment, 64 kg of coke corresponding to 20 charges of the carbon material of the actual machine was extracted from the furnace. The withdrawal time was approximately 80 minutes.
(I) After the sample was taken out, the distribution of coke was observed on the surface of the deposition surface in the furnace or on a vertical cross section in the furnace. In the case of cross-section observation, a transparent PVC plate is fixed vertically in the diameter direction of the observation surface in the furnace before the experiment, and after the experiment, a sample of one half of the PVC plate that divides the inside of the furnace into half is excavated. The half-section was observed.
II. Experimental result
After the experiment, the distribution of the raw materials on the furnace inner surface was such that the coke deposited on the wall side of the charging hopper was deposited on the furnace wall at the furnace top, and the coke deposited on the center of the charging hopper was in the center at the furnace top. Was found to have accumulated on Combining this fact with the distribution of the raw material in the vertical cross section of the furnace immediately below the charging pipe, the coke discharged from the charging hopper descends via the charging pipe and the wall of the charging hopper The coke distributed on the side descends inside the charging pipe, the coke distributed in the center of the charging hopper descends inside the charging pipe, and when the coke is fed into the furnace, The coke that has descended outside is discharged toward the furnace wall from the outside of the tip of the charging pipe, whereas the coke that has descended inside the charging pipe is located at the center of the furnace at the tip of the charging pipe. It is discharged from the part toward the furnace center. This is illustrated in FIG. Symbols 9-1 and 9-2 in FIG. 6 indicate charging pipes.
[0015]
Also, as shown in FIG. 7, even when the coke discharge speed is changed, the discharge speed of the coke deposited on the wall side in the charging hopper from the charging hopper and the coke deposited in the center of the charging hopper are not changed. The ratio of the discharge speed from the charging hopper does not change much, again, the coke deposited on the wall side of the charging hopper is deposited on the furnace wall in the furnace, and the coke deposited on the center of the charging hopper is Accumulates in the center.
[0016]
Here, as described in the section of “Prior Art”, when one charging pipe is installed in the center, fine grains are distributed in the center of the furnace as shown in FIG. In addition, coarse particles are distributed on the furnace wall, which is not preferable in operation. Although the distribution of fine particles can be shifted from the center of the furnace by installing a charging pipe at a position off the center, the center of symmetry of the particle size distribution of the carbonaceous material does not match the center axis of the furnace, and It was presumed that the symmetry of the particle size distribution of the carbonaceous material was disturbed, and it was only a disturbance factor for the operation. Even in the case of two charging pipes, the symmetry of the particle size distribution of the carbonaceous material has little effect of improvement, and the supply of the carbonaceous material into the vertical furnace using the charging pipe requires the symmetry of the particle size distribution of the carbonaceous material. From a viewpoint, it can be said that a larger number of charging pipes is preferable. However, since it is not possible to increase the number indefinitely due to the arrangement of the equipment, it is appropriate to configure at least three or more charging pipes. Furthermore, by arranging a plurality of charging pipes concentrically on the charging hopper, it is possible to effectively secure the target charging material distribution without disturbing the symmetry of the particle size distribution of the carbonaceous material.
[0017]
Non-dimensional particle size obtained by dividing the average particle size value at each sampling point by the average particle size value when not controlling the particle size distribution of the deposited coke in the radial direction in the charging hopper using four charging tubes. 3 (b) and 3 (c) show the distribution in the furnace diameter direction and the distribution in the case where the particle size distribution of the deposited coke in the radial direction of the charging hopper was controlled. FIG. 2 is a diagram showing the charging pipe position in this experiment in an azimuth direction. As apparent from FIG. 3 (b), even if four charging pipes are used without the control plate in the equalizing / discharge pressure hopper, a particle size distribution in which coarse particles accumulate in the furnace center and the furnace wall is formed. ing. This means that the high temperature gas in the furnace flows preferentially to the furnace wall due to the coarse particles deposited on the furnace wall (furnace wall flow), so from the viewpoint of protection of refractories and economy. This particle size distribution is generally not preferred.
[0018]
On the other hand, when the control plate is placed in the equalizing pressure hopper to control the particle size distribution in the charging hopper, the coke particle size in the center of the furnace can be increased and the coke particle size in the furnace wall can be reduced. It is estimated that the gas flow distribution can be brought to an operationally favorable state. At that time, as a control device of the radial particle size segregation of the raw material provided in the equalizing pressure hopper, any control plate, a rotary distributor, etc. may be used, but in particular, in the case of the control plate, a circle, a square, Alternatively, the shape may be conical. However, it is preferable that the center axis of the furnace coincides with the center of gravity of the control plate and that the center axis of the control plate is symmetric with respect to the center axis of the furnace. A bell, a combination of a bell and a bell cup, or a swirling chute may be provided in the charging hopper to control the radial grain size segregation of the raw material.
[0019]
In addition, the above results indicate that the same tendency and effect can be obtained with lump ore, sintered ore, and other carbonaceous materials instead of coke as a raw material. Many experiments have revealed that this is a phenomenon of particle size segregation.
The shape of the charging hopper is such that four cones are arranged in a cylinder, a charging pipe is attached to the tip of each hopper, and coke is supplied into the furnace via the charging pipe. Was used. Alternatively, as the shape of the charging hopper, a frustoconical projection is provided at the center of the hopper, a funnel-shaped space is formed between the frustoconical projection and the outer wall of the hopper, and a funnel-shaped space is provided at the bottom of the funnel-shaped space. It may have an inlet pipe. In addition, the structure of the charging pipe itself may be cylindrical, but a cylindrical pipe having a slightly divergent taper is preferable in order to prevent the occurrence of a bridge in the pipe. The material does not react with the furnace top gas, and especially when the furnace top temperature of the vertical smelting furnace is likely to rise, a material made of a heat-resistant alloy or a ceramic or refractory is preferable.
[0020]
Based on the novel knowledge obtained in the above model experiment, the inventor controlled the coke particle size distribution in the radial direction in the charging hopper and fed the raw material through a large number of charging pipes so as to maintain the particle size distribution. The technology for controlling the coke particle size distribution in the radial direction inside the furnace was completed by dropping the coke.
In order to control the particle size distribution of coke in the charging hopper, it is effective to adjust the deposition state of the carbonaceous material in the charging hopper. The charging pipe is arranged on a concentric circle centered on the center axis of the charging hopper or the center axis of the smelting furnace, and a control plate is provided in the equalizing pressure hopper as shown in FIG. They concluded that it was only necessary to control the movement of the carbon material when depositing the carbon material in the equalizing / discharge hopper for supplying the carbon material and when discharging the carbon material from the equalizing pressure hopper.
[0021]
【Example】
140m internal volume³  The raw material 11 is disposed on the top of the vertical smelting furnace 8 at an equal interval of 90 ° concentrically with respect to the center axis of the smelting furnace, and the raw material 11 is lowered to the top of the smelting furnace 8 by gravity. -Four vertical raw material charging pipes 9 to be filled, a charging hopper 5 connected to the charging pipe 9, means for radially applying the particle size segregation of the raw material 11 to the charging hopper 5, and A carbonaceous material was charged into the furnace using a raw material charging device including a soaking / discharging hopper 3 having means for detecting particle size segregation in the radial direction, and the charged state of the charged material was investigated.
[0022]
The equalizing / discharge hopper 3 has an inner diameter of 2200 mm, a discharge part diameter of 500 mm, a diameter of the control plate 12 of 750 mm, and a mounting position 800 mm above the lower end of the raw material 11 discharge part of the equalizing / discharge hopper 3. At this time, the distance between the control plate 12 and the equalizing pressure hopper 3 was 250 mm. Although the average particle diameter of the carbon material was 25 mm, no problem of the carbon material clogging between the control plate 12 and the equalizing pressure hopper 3 occurred.
[0023]
The coke 11 charged from the charging belt conveyor 1 is temporarily stored in the leveling hopper 3 via the receiving chute 2, and the upper seal valve 4 provided at the lower end of the receiving chute 2 is closed to discharge the coke 11. An operation for equalizing the pressures inside the pressure hopper 3 and the charging hopper 5 was performed. Subsequently, the lower seal valve 6 and the gate valve 7 were opened in this order, and the coke 11 temporarily stored in the equalizing pressure hopper 3 was discharged to the charging hopper 5. Here, the shape of the opening of the gate valve 7 was a 300 mm square, and the average discharge time of the raw material 11 was 101.5 seconds (the number of experiments n = 10). After the discharge of the raw material from the equalizing pressure hopper 3 to the charging hopper 5 was completed, the gate valve 7 and the lower seal valve 6 were closed in this order.
[0024]
The results of the experiment are summarized as shown in FIGS. 3B to 3C obtained in the model experiment, and the base (FIG. 3 (A)) in which the raw material 11 is simply supplied from the four-legged charging pipe 9 into the furnace. Compared with b)), when the control plate 12 in the equalizing pressure hopper 3 was provided (FIG. 3A), the effect of suppressing coarse particles in the furnace wall was recognized. That is, it was possible to control the carbon material particle size distribution in the radial direction in the vertical smelting furnace 8 by the presence or absence of the control plate 12 in the equalizing pressure hopper 3.
[0025]
Further, when the control plate 12 for radially controlling the raw material particle size segregation in the charging pipe hopper 5 disposed in the equalizing pressure hopper 3 for supplying the raw material to the charging hopper 5 is operated, From the imaging result of the observation camera provided at the furnace top in the smelting furnace 8, the state of the particle size segregation in the radial direction of the raw material 11 was obtained. When this was compared with the preset target value of the particle size distribution in the radial direction of the raw material 11 at the top of the vertical smelting furnace, they were almost the same. When the operation is performed in this charged state, the wear rate of the furnace wall refractories in the vertical smelting furnace 8 at three locations in the height direction and eight locations at a pitch of 45 ° in the circumferential direction at a total of 24 locations is based on the former. , There was a 10% reduction effect.
[0026]
Further, when the control plate 12 disposed on the equalizing / discharge hopper 3 is operated, the vertical smelting is performed using a horizontal sonde (a sensor for temperature and gas composition) which extends across the diameter of the top of the vertical smelting furnace 8. It is more effective to detect the gas composition distribution and the gas temperature distribution in the radial direction of the furnace 8 and to control the gas composition distribution and / or the gas temperature distribution to coincide with the target gas composition and / or the gas temperature distribution.
[0027]
In the present embodiment, in the case where the raw material discharge control plate 12 is provided as compared with the case where the control plate 12 is not provided, the average particle size of the carbon material in the central portion of the furnace can be increased and the average particle size of the carbon material in the furnace wall portion can be increased. The diameter can be suppressed. That is, under the condition that the gas flows preferentially only in the furnace wall, the thermal load on the furnace wall increases and the wear of the furnace wall is accelerated. What is necessary is just to suppress a particle size. Conversely, under the condition that almost no gas flows through the furnace wall, if the formation of the deposits on the furnace wall progresses, the deposits eventually fall off from the furnace wall, which is a significant hindrance to stable operation. It is only necessary to promote the average particle size of the carbon material on the furnace wall without using it.
[0028]
Further, by changing the size and the mounting position of the control plate 12, the state of accumulation and discharge of the carbon material in the charging hopper 5 can be changed, and the particle size distribution of the carbon material in the hopper can be controlled. The coke deposited on the wall deposits on the furnace wall in the furnace, and the coke deposited on the center of the hopper deposits on the center of the furnace.Therefore, the particle size distribution of the carbon material in the furnace can be controlled. Absent.
[0029]
Next, the same internal volume 140 m as in the above embodiment³  Another filling survey was conducted using a vertical furnace. At that time, as shown in FIG. 8, a conical wear-resistant cast steel bell 13 having a bottom diameter of 2400 mm and a height of 1200 mm was attached to the charging hopper 5. The distance between the lower end of the bell 13 and the flat bottom portion 14 of the charging hopper 5 was 1000 mm, and the bell 13 was fixed so that the center axis of the bell 13 and the center axis of the vertical smelting furnace 8 coincided with each other. The inner diameter of the charging hopper 5 was 3300 mm, the diameter of the bottom of the bell 13 was 2400 mm, and the clearance between the inner wall of the charging pipe 9 and the bell 13 was 450 mm. No. 11 was deposited in the charging hopper 5 without any problem, and dropped down the charging pipe 9. The number of charging tubes is also four in this case, and they are arranged concentrically with respect to the central axis of the vertical smelting furnace. However, under the condition in which only the bell 13 is provided in the charging hopper 5 shown in FIG. 8B, the carbon material from a specific slope of the bell 13 depends on the state of the carbon material 11 falling from the equalizing pressure hopper 3. There was a case where the deposition of the carbonaceous material 11 was uneven in the circumferential direction inside the vertical smelting furnace 8 in some cases.
[0030]
The carbonaceous material 11 charged from the charging belt conveyor 1 was temporarily stored in the equalizing / discharge pressure hopper 3 via the receiving chute 2. The upper seal valve 4 provided at the lower end of the receiving chute 2 was closed, and the operation of equalizing the pressure inside the equalizing pressure hopper 3 and the inside of the charging hopper 5 was performed. Next, the lower seal valve 6 and the gate valve 7 were opened in this order, and the carbonaceous material 11 temporarily stored in the equalizing pressure hopper 3 was discharged to the charging hopper 5. Here, the diameter of the opening of the gate valve 7 was 300 mm, and the average discharge time of the carbonaceous material 11 was 103.7 seconds (the number of experiments n = 10). After the discharge of the carbonaceous material 11 from the equalizing pressure hopper 3 to the charging hopper 5 is completed, the gate valve 7 and the lower seal valve 6 are closed in this order. FIG. 3 (d) summarizes the results of the experiment at this time. Compared to the base condition in which the carbonaceous material 11 was simply supplied from the four-legged charging pipe into the furnace without inferring the inference of the present inventors. Thus, by controlling the shape of the carbon material 11 deposited in the charging hopper 5, the effect of increasing the average particle size in the center of the furnace and suppressing coarse particles in the furnace wall was recognized.
[0031]
In the case as shown in FIG. 8B in which the bell 13 is merely installed in the charging hopper 5, the carbon material 11 falls on the specific slope of the bell 13 depending on the state of the carbon material 11 dropping from the equalizing pressure hopper 3. , And the amount of the carbonaceous material 11 accumulated in the circumferential direction in the furnace may become uneven. On the other hand, as shown in FIG. 8C, the bell cup 15 is combined with the bell 13 installed in the charging hopper 5, and once the carbonaceous material 11 is deposited between the bell 13 and the bell cup 15, When the bell cup 15 is disposed so that the carbon material 11 falls from the gap between the bell 13 and the bell cup 15 by descending the bell 13 (see FIG. 9), the carbon material 11 is caused to drift on the bell 13. The variation in the amount of carbon material falling in the circumferential direction was reduced. In this case, the bell 13 or the bell cup 15 installed in the charging hopper 5 needs to have a movable structure, for example, a bell that can be driven up and down as seen in a blast furnace.
[0032]
In contrast to the above-described embodiment in which the bell 13 is installed in the charging hopper 5 or the bell 13 and the bell cup 15 are installed, as shown in FIG. Investigations were also made when placed in the circumferential direction. There, when the carbonaceous material 11 falls into the furnace from the tip of the bell 13, as shown in FIG. 9, after the carbonaceous material 11 collides with the movable armor 16 whose position is adjusted in the furnace radial direction, the vertical type Since the carbon material 11 comes to fall into the smelting furnace 8, the falling position of the carbonaceous material 11 in the furnace radial direction could be easily controlled. Further, as shown in FIG. 8 (e), when a bellless chute 17 that can be tilted and turned is installed in the charging hopper 5 to adjust the shape of the deposited carbon material 11 in the charging hopper 5, a vertical smelting furnace is provided. The falling position of the carbonaceous material 11 falling into the inside 8 can be controlled with higher accuracy than in the case of FIG. In this embodiment using bells, bell cups and removable armor or bellless chutes, these devices are located in the charging hopper, not at the top of the furnace, and communicate with the furnace through the charging tube but with hot gas. Does not enter the charging hopper from the top of the furnace, so there is no problem regarding the service temperature in the equipment.
[0033]
【The invention's effect】
In the vertical smelting furnace, raw material charging using the charging tube method does not have a movable armor or a rotating chute like a blast furnace, so the equipment structure is relatively simple, and the equipment cost in the smelting furnace is relatively low. Inexpensive and easy maintenance of equipment. In the present invention, while taking advantage of such advantages, the particle size segregation distribution of carbonRealIt has been revealed.
[0034]
As a result, it is possible to withstand high temperatures, prevent gas from flowing preferentially only to the furnace wall, reduce the increase in thermal load on the furnace wall, and suppress furnace wall wear.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the concept of a raw material charging method according to the present invention.
FIG. 2 is a diagram showing a charging pipe position in a model experiment in an azimuth direction.
FIG. 3 is a diagram showing average particle size distributions (c) and (d) in the furnace radial direction at the furnace top when the present invention was tested using the apparatus shown in FIG. 1, and comparative examples (a) and (b). It is.
FIG. 4 is a diagram showing a specific device configuration of a vertical smelting furnace.
FIG. 5 is a diagram showing a method of performing a model experiment.
FIG. 6 shows the results of an investigation of the state of falling of the raw material from the charging hopper into the furnace by a model experiment. It is a figure showing distribution.
FIG. 7 is a result of investigating an influence of a raw material discharging speed from a charging hopper by a model experiment.
8A and 8B are diagrams showing an embodiment of a raw material charging method according to the present invention, wherein FIG. 8A is a conventional example, and FIG. 8B is a bell for causing particle size segregation of deposited raw material in a charging hopper; (c) shows a case using a bell and a bell cup, (d) shows a case using a bell and a movable armor, and (e) shows a case using a bellless shoot. The arrows in the figure indicate the movement of the carbonaceous material.
FIG. 9 shows a state in which the carbon material falls from between the bell and the bell cup. FIG. 9 (a) shows the situation where the carbon material is deposited between the bell, the bell and the bell cup using the apparatus of FIG. FIG. 7C is a diagram showing a state of carbon material falling when a movable armor is not used, and FIG.
FIG. 10 shows a carbon material accumulation state in a charging hopper using a bellless chute.
[Explanation of symbols]
1 charging conveyor
2 Receiving chute
3 Equal discharge hopper
4 Upper seal valve
5 Loading hopper
6 Lower seal valve
7 Gate valve
8 Furnace body (vertical refining furnace)
9 Charge pipe
10 Thin iron plate partitions
11 Raw materials (coke)
12 Control board
13 Bell
14 Flat bottom of charging hopper
15 Bell Cup
16 Movable Armor
17 Bellless Shoot

Claims

When the raw material is charged into the furnace through the equalizing / discharge hopper, the charging hopper, and the charging pipe provided above the furnace of the vertical smelting furnace, the raw material deposited in the charging hopper is reduced by the radius of the raw material. The directional smelting furnace is adjusted so that it is almost the same as the radial grain size segregation of the target raw material at the top of the vertical smelting furnace, and is charged into the furnace through a plurality of charging pipes. Material loading method for vertical smelting furnaces.

The vertical smelting furnace has a plurality of tuyeres provided in at least two upper and lower stages in which a packed layer of a carbon-based solid reducing agent is formed in the furnace and high-temperature air or powder material is blown into the packed layer. The method for charging a raw material for a vertical smelting furnace according to claim 1, wherein the raw material is a carbon material.

3. The vertical as claimed in claim 1, wherein the segregation in the radial direction of the raw material deposited in the charging hopper is adjusted by a bell, a combination of a bell and a bell cup, or a swiveling chute disposed in the charging hopper. How to charge raw materials for mold smelting furnace.