JP2004309067A - Method of using blast furnace gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve energy use efficiency by manufacturing reformed blast furnace gas by removing and separating CO<SB>2</SB>from blast furnace gas, and effectively combining the reformed blast furnace gas, coke oven gas and converter gas in a steel mill for use. <P>SOLUTION: In the method of using blast furnace gas, the reformed blast furnace gas of high calorific value manufactured by carrying out oxygen enriching blast furnace gas besides removal and separation of CO<SB>2</SB>from blast furnace gas of low calorific value is substituted for a part or all of any one or more kinds of blast furnace gas, coke oven gas, converter gas and LPG used as any one or more kinds of fuel gas out of air-heating furnace fuel gas, coke oven fuel gas and power generating fuel gas. A part or all of the economized coke oven gas is blasted from a blast furnace tuyere and used as a reducing agent in a blast furnace or used as reducing gas for reducing iron ore. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００７１】
【表２】

【００７２】
実施例１は、比較例の発熱量７６８ｋｃａｌ／Ｎｍ^３の高炉ガスからＣＯ_２を除去分離して発熱量９７２ｋｃａｌ／Ｎｍ^３の改質高炉ガスを製造した例である。
【００７３】
実施例１においては、改質高炉ガスの発熱量が９００ｋｃａｌ／Ｎｍ^３以上であるから、高炉送風用の熱風炉燃料ガスとして溶銑１トン当り必要な４３１Ｍｃａｌ／ｔ−ｐの全量に使用することが可能であり、比較例において、高炉送風用の熱風炉燃料ガスとして溶銑１トン当り使用していた高価な高カロリーガスであるコークス炉ガス６３Ｍｃａｌ／ｔ−ｐの全量と転炉ガス１７ Ｍｃａｌ／ｔ−ｐの全量とが改質高炉ガスを代替使用することによって節約できた。
【００７４】
また、実施例１においては、発熱量１０００ｋｃａｌ／Ｎｍ^３以上のコークス炉燃料ガスにするために、改質高炉ガスに溶銑１トン当り１９Ｍｃａｌ／ｔ−ｐの転炉ガスを混合すればよく、比較例において、コークス炉燃料ガスとして溶銑１トン当り使用していた高価な高カロリーガスであるコークス炉ガス７２Ｍｃａｌ／ｔ−ｐの全量と転炉ガス６３Ｍｃａｌ／ｔ−ｐのうちの４４Ｍｃａｌ／ｔ−ｐとが改質高炉ガスを代替使用することによって節約できた。
【００７５】
さらに、実施例１においては、節約したコークス炉ガスと転炉ガスの一部を改質高炉ガスに混合して他工程で必要な電力を製造するための発電用燃料ガスとしている。
【００７６】
この発電用燃料ガスは１０００ｋｃａｌ／Ｎｍ^３以上の発熱量となり、特許文献３で提示されているように、このガスをガスタービン用燃料に用いてガスタービンにて発電するとともに、ガスタービン発電とボイラー及びスチームタービン発電とを組み合わせたコンバインド・サイクル発電を行うことにより、発電効率を比較例の３５％から実施例１の４５％に高められた。
【００７７】
その結果、溶銑１トン当り他工程で使用する電力２８１ｋＷｈを製造するための発電用燃料ガスは溶銑１トン当り１５３Ｍｃａｌ／ｔ−ｐ節約できた。
【００７８】
実施例１で節約できたエネルギーは脱ＣＯ_２用エネルギーに使用することが可能である。実施例１では、溶銑１トン当りの高炉ガスからの脱ＣＯ_２量は３４８Ｎｍ^３／ｔ−ｐであり、ＣＯ_２単位体積当りの脱ＣＯ_２エネルギー原単位が１．３６Ｍｃａｌ／Ｎｍ^３−ＣＯ_２（２．９ＭＪ／ｋｇ−ＣＯ_２に相当する）なので、溶銑１トン当りの脱ＣＯ_２用エネルギーは４７３Ｍｃａｌ／ｔ−ｐ必要である。
【００７９】
比較例に対し、実施例１で節約できたエネルギー１５３Ｍｃａｌ／ｔ−ｐと高炉スラグからの回収顕熱８０Ｍｃａｌ／ｔ−ｐとを脱ＣＯ_２用エネルギーとして使用することによって、新規に調達すべきエネルギーは溶銑１トン当り２４０Ｍｃａｌ／ｔ−ｐでよい。
【００８０】
すなわち、実施例１では、溶銑１トン当り高炉ガスからＣＯ_２を３４８Ｎｍ^３／ｔ−ｐ除去分離するエネルギーとして必要な４７３Ｍｃａｌ／ｔ−ｐを含めた、溶銑１トン当りのエネルギー消費量の増加は、比較例に対し２４０Ｍｃａｌ／ｔ−ｐとなり、実質的にはＣＯ_２を３４８Ｎｍ^３／ｔ−ｐを２４０Ｍｃａｌ／ｔ−ｐで除去分離できたこととなり、ＣＯ_２単位体積当りの実質的な脱ＣＯ_２エネルギー原単位は０．６９Ｍｃａｌ／Ｎｍ^３−ＣＯ_２に低下することができた。
【００８１】
実施例２は、高炉ガスからＣＯ_２を除去分離して製造した改質高炉ガスを高炉送風用の熱風炉燃料ガス及びコークス炉燃料ガスとして、高価な高カロリーガスであるコークス炉ガスと転炉ガスに代替して使用することによって、節約できたコークス炉ガスを高炉羽口から吹込んで高価な購入コークス使用量の削減を実施したものである。
【００８２】
溶銑１トン当り２１５Ｍｃａｌ／ｔ−ｐのコークス炉ガスを高炉羽口から吹込むと同時に、酸素富化率を比較例の２．５％から５．６％に上昇させたことにより、高炉ガスからＣＯ_２を除去分離して製造した改質高炉ガスの発熱量は１１５６ｋｃａｌ／Ｎｍ^３となった。
【００８３】
その結果、高炉送風用の熱風炉燃料ガス及びコークス炉燃料ガスとして改質高炉ガスを全量使用することが可能となり、高炉送風用の熱風炉燃料ガスおよびコークス炉燃料ガスとして使用していた高価な高カロリーガスであるコークス炉ガスの全量と転炉ガスの全量とが節約できた。
【００８４】
さらに、実施例２においては、発熱量が１１５６ｋｃａｌ／Ｎｍ^３の改質高炉ガスを発電用燃料ガスとして使用することによって、特許文献３で提示されているように、これをガスタービン用燃料に用いてガスタービンにて発電するとともに、ガスタービン発電とボイラー及びスチームタービン発電とを組み合わせたコンバインド・サイクル発電を行うことにより、発電効率を比較例の３５％から実施例２の４５％に高められる。
【００８５】
その結果、他工程で使用する電力を製造するための発電用燃料ガスは溶銑１トン当り１１５Ｍｃａｌ／ｔ−ｐ節約できた。また、高炉プロセスにおいて使用している熱風炉燃料の減少と高炉ガス回収量の増加により、比較例に対し実施例２においては、溶銑１トン当り４９Ｍｃａｌ／ｔ−ｐの高炉プロセスでのエネルギー消費が節約できた。
【００８６】
実施例２で節約できたエネルギーは、脱ＣＯ_２用エネルギーに使用することが可能である。実施例２では、溶銑１トン当りの高炉ガスからの脱ＣＯ_２量は３２８Ｎｍ^３／ｔ−ｐであり、ＣＯ_２単位体積当りの脱ＣＯ_２エネルギー原単位が１．３６Ｍｃａｌ／Ｎｍ^３−ＣＯ_２であるから、溶銑１トン当りの脱ＣＯ_２用エネルギーは４４６Ｍｃａｌ／ｔ−ｐ必要である。
【００８７】
比較例に対し、実施例２で節約できたエネルギー１１５Ｍｃａｌ／ｔ−ｐと４９Ｍｃａｌ／ｔ−ｐ、及び、高炉スラグからの回収顕熱８０Ｍｃａｌ／ｔ−ｐを脱ＣＯ_２用エネルギーに使用することによって、新規に調達すべきエネルギーは溶銑１トン当り２０２Ｍｃａｌ／ｔ−ｐとなった。
【００８８】
さらに、高価な購入コークス使用量を約７ｋｇ／ｔ−ｐ節約でき、燃料比の低下による高炉プロセスでのエネルギー消費量の低下５０Ｍｃａｌ／ｔ−ｐも考慮すると、脱ＣＯ_２エネルギーも含めた銑鉄製造エネルギー全体の増分は、比較例に対し、溶銑１トン当り１５２Ｍｃａｌ／ｔ−ｐとなる。
【００８９】
すなわち、実施例２では、溶銑１トン当り高炉ガスからＣＯ_２を３２８Ｎｍ^３／ｔ−ｐ除去分離するエネルギーとして必要な４４６Ｍｃａｌ／ｔ−ｐを含めた、溶銑１トン当りのエネルギー消費量の増加は、比較例に対し１５２Ｍｃａｌ／ｔ−ｐとなり、実質的には、３２８Ｎｍ^３／ｔ−ｐのＣＯ_２を１５２Ｍｃａｌ／ｔ−ｐで除去分離できたこととなり、ＣＯ_２単位体積当りの実質的な脱ＣＯ_２エネルギー原単位は、０．４６Ｍｃａｌ／Ｎｍ^３−ＣＯ_２に低下することができた。
【００９０】
実施例３は、高炉ガスからＣＯ_２を除去分離して製造した改質高炉ガスを高炉送風用の熱風炉燃料ガス及びコークス炉燃料ガスとして、高価な高カロリーガスであるコークス炉ガスと転炉ガスに代替して使用することによって、節約できたコークス炉ガスと改質高炉ガスとを用いて鉄鉱石を還元して製造した還元鉄を高炉に使用して高価な購入コークス使用量の削減を実施したものである。
【００９１】
実施例３においては、改質高炉ガスの発熱量は９７６ｋｃａｌ／Ｎｍ^３となり、発熱量が９００ｋｃａｌ／Ｎｍ^３以上であるから、高炉送風用の熱風炉燃料ガスとして、この改質高炉ガスを全量使用することが可能であり、高価な高カロリーガスであるコークス炉ガス全量と転炉ガス全量とを節約できた。
【００９２】
また、実施例３においては、発熱量１０００ｋｃａｌ／Ｎｍ^３以上のコークス炉燃料ガスにするために、改質高炉ガスに溶銑１トン当り１６Ｍｃａｌ／ｔ−ｐの転炉ガスを混合すればよく、比較例において、コークス炉燃料ガスとして溶銑１トン当り使用していた高価な高カロリーガスであるコークス炉ガスの全量と転炉ガスの一部とが改質高炉ガスを代替使用することによって節約できた。
【００９３】
さらに、実施例３においては、節約した転炉ガスの一部を改質高炉ガスに混合して他工程で必要な電力を製造するための発電用燃料ガスとしている。この発電用燃料ガスは１０００ｋｃａｌ／Ｎｍ^３以上の発熱量となり、特許文献３で提示されているように、このガスをガスタービン用燃料に用いてガスタービンにて発電するとともに、ガスタービン発電とボイラー及びスチームタービン発電とを組み合わせたコンバインド・サイクル発電を行うことにより発電効率を比較例の３５％から実施例３の４５％に高められた。
【００９４】
その結果、溶銑１トン当り他工程で使用する電力２８１ｋＷｈを製造するための発電用燃料ガスは溶銑１トン当り１５３Ｍｃａｌ／ｔ−ｐ節約できた。また、高炉プロセスにおいて、燃料費が低下することによる高炉ガス発生量の減少により、エネルギー消費量は溶銑１トン当り１５Ｍｃａｌ／ｔ−ｐ増加した。
【００９５】
なお、実施例３の還元鉄製造プロセスでは、コークス炉ガスを酸素で部分燃焼して高温の還元ガスを製造するとともに、この高温の還元ガスに鉄鉱石を還元して金属鉄を生成させる能力のある常温の改質高炉ガスを混合して、還元炉での反応に適した温度に調整された還元ガスを製造し、これを使用して、還元率８５％の還元鉄を溶銑１トン当り４０ｋｇ／ｔ−ｐ製造した。
【００９６】
このとき、コークス炉ガスを１１４Ｍｃａｌ／ｔ−ｐ、改質高炉ガスを１７Ｍｃａｌ／ｔ−ｐ、及び、酸素を製造エネルギー換算して５Ｍｃａｌ／ｔ−ｐ使用した。
【００９７】
また、還元炉からの排出されるＣＯ及びＨ_２成分を含む高温の排ガスから回収した潜熱と顕熱、及び、還元炉から排出された高温の還元鉄から回収した顕熱の合計は８２Ｍｃａｌ／ｔ−ｐであった。使用したエネルギーから回収したエネルギーを控除した、この本還元鉄製造プロセスでのエネルギー消費量は、溶銑１トン当り５９Ｍｃａｌ／ｔ−ｐであった。
【００９８】
すなわち、実施例３では、高炉プロセスで溶銑１トン当り１５Ｍｃａｌ／ｔ−ｐのエネルギー消費量の増加と還元鉄製造プロセスで溶銑１トン当り５９Ｍｃａｌ／ｔ−ｐのエネルギー消費量の増加があるものの、他工程電力製造で溶銑１トン当り１５３Ｍｃａｌ／ｔ−ｐエネルギー消費量を節約できたので、比較例に対し、実施例３においては、溶銑１トン当り７９Ｍｃａｌ／ｔ−ｐエネルギー消費量を節約できた。
【００９９】
実施例３で節約できたエネルギーは、脱ＣＯ_２用エネルギーに使用することが可能である。実施例３では、溶銑１トン当りの高炉ガスからの脱ＣＯ_２量は３３９Ｎｍ^３／ｔ−ｐであり、ＣＯ_２単位体積当りの脱ＣＯ_２エネルギー原単位が１．３６Ｍｃａｌ／Ｎｍ^３−ＣＯ_２（２．９ＭＪ／ｋｇ−ＣＯ_２に相当する）なので、溶銑１トン当りの脱ＣＯ_２用エネルギーは４６１Ｍｃａｌ／ｔ−ｐ必要である。
【０１００】
比較例に対し、実施例３で節約できたエネルギー７９Ｍｃａｌ／ｔ−ｐと高炉スラグからの回収顕熱８０Ｍｃａｌ／ｔ−ｐとを脱ＣＯ_２用エネルギーとして使用することによって、新規に調達すべきエネルギーは溶銑１トン当り３０１Ｍｃａｌ／ｔ−ｐでよい。
【０１０１】
さらに、高価な購入コークス使用量を比較例に対し約１１ｋｇ／ｔ−ｐ節約でき、燃料比の低下による高炉プロセスでのエネルギー消費量の低下７９Ｍｃａｌ／ｔ−ｐも考慮すると、脱ＣＯ_２エネルギーも含めた銑鉄製造エネルギー全体の増分は、溶銑１トン当り２２２Ｍｃａｌ／ｔ−ｐとなる。
【０１０２】
すなわち、実施例３では、溶銑１トン当り高炉ガスからＣＯ_２を３３９Ｎｍ^３／ｔ−ｐ除去分離するエネルギーとして必要な４６１Ｍｃａｌ／ｔ−ｐを含めた、溶銑１トン当りのエネルギー消費量の増加は、比較例に対し２２２Ｍｃａｌ／ｔ−ｐとなり、実質的には、３３９Ｎｍ^３／ｔ−ｐのＣＯ_２を２２２Ｍｃａｌ／ｔ−ｐで除去分離できたこととなり、ＣＯ_２単位体積当りの実質的な脱ＣＯ_２エネルギー原単位は０．６６Ｍｃａｌ／Ｎｍ^３−ＣＯ_２に低下することができた。
【０１０３】
本発明の実施例によれば、製鉄所において、高炉送風用の熱風炉燃料ガス、コークス炉燃料ガス及び発電用燃料ガスの一部として利用されている高炉炉頂から排出される高炉ガスからＣＯ_２を除去分離することによって、発熱量の高い改質高炉ガスを製造し、これを、高炉送風用の熱風炉燃料ガス又はコーク炉燃料ガスの全部又は一部として利用することによって高価な高カロリーガスであるコークス炉ガス及び転炉ガスを節約し、発電効率を上昇可能とする発電用燃料ガスとして利用したり、高炉へのコークス炉ガス吹込みに利用して高価な購入コークス量を削減したり、還元鉄を製造し、これを高炉に装入して高価な購入コークス量を削減したり、地球温暖化防止のための対策としてのＣＯ_２の除去分離に必要なエネルギーを実質的に低減できるなどの有効な利用方法が可能であることが示された。
【０１０４】
【発明の効果】
以上述べたように、本発明によれば、高炉ガスからＣＯ_２を除去分離した改質高炉ガスを製造し、製鉄所において改質高炉ガス、コークス炉ガス及び転炉ガスとを有効に組み合わせて利用することによってエネルギー使用効率の向上が可能となり、工業上及び地球温暖化防止に有用な効果が期待できる。
【図面の簡単な説明】
【図１】現状の、高炉ガス、コークス炉ガス及び転炉ガスの利用形態を示す概念図である。
【図２】本発明の、改質高炉ガス、コークス炉ガス及び転炉ガスの利用形態を示す概念図である。
【図３】本発明の、コークス炉ガスを高炉に吹込んだときの、改質高炉ガス、コークス炉ガス及び転炉ガスの利用形態を示す概念図である。
【図４】本発明の、還元鉄を高炉に装入したときの、改質高炉ガス、コークス炉ガス及び転炉ガスの利用形態を示す概念図である。
【符号の説明】
１…高炉
２…熱風炉
３…コークス炉
４…焼結機
５…炉頂圧回収発電設備
６…転炉
７…発電所
８…加熱炉等
９…脱ＣＯ_２プロセス
１０…還元鉄製造還元炉
１１…高炉ガス
１２…炉頂圧回収回収電力
１３…コークス炉ガス
１４…転炉ガス
１５…コークス
１６…微粉炭
１７…購入コークス
１８…鉱石
１９…空気
２０…酸素
２１…熱風
２２…溶銑及び溶滓
２３…改質高炉ガス
２４…ＣＯ_２吸収液再生用エネルギー
２５…分離除去ＣＯ_２
２６…余剰改質高炉ガス
２７…酸素
２８…部分燃焼炉
２９…高温還元ガス
３０…還元ガス
３１…還元炉排ガス
３２…還元鉄[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a method for reducing CO 2 in blast furnace gas.₂The present invention relates to a method for producing a reformed blast furnace gas having a large calorific value by removing and separating the same, and using the gas as a fuel gas or a reducing gas.
[0002]
[Prior art]
In an ironworks, blast furnace gas discharged from the blast furnace furnace top is effectively used as a part of hot blast stove fuel gas, coke oven fuel gas, and fuel gas for power generation.
[0003]
However, in the above prior art, the calorific value of the blast furnace gas is 680 to 850 kcal / Nm.³(Refer to Non-patent Document 1), which is 900 kcal / Nm³Hot stove fuel gas with the above calorific value or 1000 kcal / Nm³When used as a coke oven fuel gas or a power generation fuel gas having the above calorific value, 2000 kcal / Nm of coke oven gas, converter gas, LPG, LNG, etc.³It is necessary to mix a high calorie gas having the above calorific value.
[0004]
Since coke oven gas and converter gas are by-product gases generated from the inside of steelworks, they are economical without additional external purchase costs, but coke oven gas and converter gas have a large calorific value. Therefore, it is used as a fuel gas for steel heating furnaces and the like in steelworks downstream processes.
[0005]
Therefore, depending on fluctuations in energy supply and demand at steelworks, expensive high-calorie gas such as LPG or LNG is newly purchased in order to supplement coke oven gas and converter gas, which are high calorie gases that are likely to be in short supply. In some cases, there is a problem that blast furnace gas, which is a low-calorie gas, is released.
[0006]
Patent Document 1 discloses a method of stabilizing the operation of a blast furnace when a large amount of pulverized coal is injected by blowing coke oven gas into a blast furnace in addition to pulverized coal injection.
[0007]
However, from the fuel balance of the entire steelworks, if coke oven gas is used in the blast furnace, the fuel such as the hot blast furnace fuel gas for blast furnace ventilation, the coke oven fuel gas, the fuel gas for power generation, or the steel heating furnace in the downstream process of the steelworks. The amount of coke oven gas used as gas or the like is insufficient, and expensive high-calorie gas such as LPG or LNG is newly purchased, which in turn increases the production cost of the entire steelworks.
[0008]
Furthermore, it is known that the blast furnace fuel ratio can be reduced by preliminarily reducing and charging the blast furnace raw material ore until metallic iron is produced and charging the ore into the blast furnace (see Non-Patent Document 2).₂Is reduced to only FeO because of its small reduction capacity, and it is impossible to use blast furnace gas as a reducing gas for pre-reducing the ore charged to the blast furnace until metallic iron is produced. is there.
[0009]
However, using inorganic solid matter from blast furnace gas₂A method for removing and separating is disclosed in Patent Document 2.
[0010]
However, the method disclosed in Patent Document 2 discloses that CO 2₂This method uses the time difference (retention time difference) between the adsorption and desorption of an inorganic solid substance with the other component gas. The reaction vessel alone filled with the inorganic solid substance is a batch process, and is a continuous process like blast furnace gas. When it is necessary to process a large amount of blast furnace gas, it is necessary to install a large number of reaction vessels in parallel and switch the gas flow path to allow the blast furnace gas to pass through the reaction vessels, which increases equipment costs.
[0011]
In addition, as shown in Non-Patent Document 3, coal is converted to CO₂Iron ore is reduced using the reducing gas produced by partial combustion in the furnace, and the exhaust gas used for the reduction is continuously CO2₂To remove CO2₂The latter gas (referred to as process gas) is reheated and recycled as a reducing gas.
[0012]
However, coal is₂The reduced gas partially burned by N₂Low concentration, N in the process gas₂The concentration is also low.
[0013]
On the other hand, in a blast furnace, coke or pulverized coal is burned at the tuyere with air or oxygen-enriched air to produce a high-temperature reducing gas.₂High concentration and still more than 30% N in reformed blast furnace gas₂Is included.
[0014]
But N₂Does not participate in the reduction reaction of iron ore,₂In highly reformed blast furnace gas, CO and H contribute to reduction.₂Is heated to the temperature required for the reduction reaction,₂Heating at the same time until the above N₂Since the energy required for heating is larger than that of a process gas having a low concentration,₂It is not energy efficient to use only the reformed blast furnace gas having a high concentration as the reducing gas.
[0015]
[Patent Document 1]
JP-A-4-268003
[Patent Document 2]
JP-A-8-141357
[Patent Document 3]
JP-A-11-35950
[Non-patent document 1]
The Iron and Steel Institute of Japan: Steel Handbook, 3rd Edition, Volume 2, Chapter 5, Section 6, Section 2
[Non-patent document 2]
Shigetomi Akitoshi: Ironmaking Handbook, Jinjinshokan, (1979), P.S. 200
[Non-Patent Document 3]
W. Schlebush: MPT International 5 (1997), p. 52
[Non-patent document 4]
Taiichiro Suda et al .: Energy and Resources, 23 (2002), p. 307
[0016]
[Problems to be solved by the invention]
In order to solve these problems, the present inventors have proposed a method of effectively utilizing blast furnace gas as a hot blast stove fuel gas for blast furnace blowing, a coke oven fuel gas, or a fuel gas for power generation, and a reforming blast furnace. The objective was to develop a method to utilize coke oven gas saved by effective use of gas.
[0017]
[Means for Solving the Problems]
The present invention has been made to solve the above problems in the conventional method, and the gist thereof is as follows.
[0018]
(1) 900 kcal / Nm discharged from the blast furnace top³Blast furnace gas less than CO₂900 kcal / Nm³The above reformed blast furnace gas is produced, and the reformed blast furnace gas is used as one or more of a hot blast furnace fuel gas, a coke oven fuel gas, and a fuel gas for power generation. 900kcal / Nm³Blast furnace gas of less than 2000 kcal / Nm³A method of using a blast furnace gas, wherein the method replaces any or all of the above coke oven gas, converter gas, and LPG.
[0019]
(2) Add oxygen to the air for blast furnace blast and add N₂While reducing the concentration to 50% or less, CO₂1000 kcal / Nm³The above reformed blast furnace gas is produced, and the reformed blast furnace gas is used as one or more of a hot blast furnace fuel gas, a coke oven fuel gas, and a fuel gas for power generation. 900kcal / Nm³Blast furnace gas of less than 2000 kcal / Nm³A method of using as a blast furnace gas, which is substituted for part or all of any one or more of the above coke oven gas, converter gas, and LPG.
[0020]
(3) The method for utilizing blast furnace gas according to (1) or (2), wherein part or all of the coke oven gas is blown from a blast furnace tuyere.
[0021]
(4) 900 kcal / Nm discharged from the blast furnace top³Blast furnace gas less than CO₂900kcal / Nm manufactured by removing and separating³Oxygen is added to the above reformed blast furnace gas or blast furnace blast air to add N to the blast furnace gas.₂While reducing the concentration to 50% or less, CO₂Kcal / Nm manufactured by removing and separating³A method of using blast furnace gas, wherein the reforming blast furnace gas and part or all of the coke oven gas are used in a reduction furnace as a reducing gas for reducing iron ore.
[0022]
(5) The method for utilizing blast furnace gas according to (4), wherein the reduced iron produced in the reduction furnace is charged into a blast furnace.
[0023]
(6) The CO₂The blast furnace gas according to any one of the above (1) to (5), wherein the separation of the blast furnace gas is performed by any one of a gas absorption method, a cryogenic separation method, a gas adsorption method, and a membrane separation method. How to Use.
[0024]
(7) The method for utilizing blast furnace gas according to (6), wherein the gas absorption method is a chemical absorption method using an amine-based absorbing solution.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
In order to solve the above-mentioned problem and to develop a method for effectively utilizing the blast furnace gas, the present inventor has found that the blast furnace gas discharged from the blast furnace₂It has been found that a high calorie reformed blast furnace gas having a higher calorific value per unit volume can be produced and used as a fuel or a reducing gas.
[0026]
19-25 vol% CO in blast furnace gas, CO₂Is 19 to 25 vol%, H₂Is contained in an amount of 3 to 6% by volume, and the remaining components are N₂And the calorific value of the blast furnace gas is 650-850 kcal / Nm³However, the gas absorption method, cryogenic separation method (distillation method), gas adsorption method (pressure swing adsorption method and temperature swing adsorption method), membrane separation method, etc.₂900 kcal / Nm³The reformed blast furnace gas having the above calorific value can be produced.
[0027]
The high-calorie reformed blast furnace gas can be used as a fuel or a reducing gas having higher added value than the low-calorie blast furnace gas.
[0028]
That is, 900 kcal / Nm³It is possible to use the entire amount of the reformed blast furnace gas having the above calorific value as a hot blast stove fuel gas, and to use coke oven gas, converter gas, LPG, LNG, etc. conventionally used as a hot blast stove gas in a blast furnace gas mixture. 2000kcal / Nm³It is possible to save all the amount of high calorie gas having the above calorific value.
[0029]
Also, this reformed blast furnace gas was supplied at 1000 kcal / Nm.³When used as a part of a coke oven fuel gas or a power generation fuel gas having the above calorific value, coke oven gas, converter gas, LPG which is conventionally used as a coke oven fuel gas or a power generation fuel gas in a blast furnace gas mixture is used. 2000kcal / Nm such as LNG³Part of the amount of expensive high-calorie gas having the above calorific value can be saved.
[0030]
Blast furnace gas to CO₂CO concentration in the reformed blast furnace gas produced by removing and separating₂The lower the concentration, the greater the calorific value of the reformed blast furnace gas and the higher the utility value of the reformed blast furnace gas. When the fuel ratio of the blast furnace is high, the calorific value of the blast furnace gas is large.₂The calorific value of the reformed blast furnace gas obtained by removing and separating the gas is large.
[0031]
However, increasing the fuel ratio of the blast furnace means that the input energy for producing pig iron increases, which is not preferable in terms of energy efficiency.
[0032]
On the other hand, O₂Blast furnace blasting O₂O concentration in air₂Concentration higher than 21%, N in blast furnace gas₂By reducing the concentration to 50% or less, CO₂1000 kcal / Nm³The reformed blast furnace gas having the above calorific value can be produced.
[0033]
This high-calorie reformed blast furnace gas can be used in its entirety as a hot blast stove fuel gas, a coke oven fuel gas or a fuel gas for power generation, and is conventionally used as a hot blast stove fuel gas, a coke oven fuel gas or a fuel gas for power generation. 2000 kcal / Nm of coke oven gas, converter gas, LPG, LNG, etc. mixed with blast furnace gas³It is possible to save all the amount of expensive high-calorie gas having the above calorific value.
[0034]
The coke oven gas and converter gas having a large calorific value saved here can be used as a heating furnace fuel gas. As a result, the purchase amount of expensive high-calorie gas such as LPG or LNG used as the heating furnace fuel gas can be reduced.
[0035]
Also, by blowing the saved coke oven gas as fuel from the blast furnace tuyere, the use of coke oven gas in the entire steelworks is balanced, and the purchase amount of expensive high calorie gas such as LPG or LNG is reduced. Without increasing, it is possible to reduce fuel and improve productivity of the blast furnace as disclosed in Patent Document 1.
[0036]
Blast furnace gas is CO₂, The iron ore has a low reducing ability and cannot produce metallic iron. However, from this blast furnace gas, CO₂Blast furnace gas from which CO was removed and separated was CO and H₂And N₂It has sufficient reducing ability to produce metallic iron, and it is possible to reduce iron ore using this reformed blast furnace gas to convert some or all of iron oxide in iron ore to metallic iron. it can.
[0037]
Furthermore, the blast furnace fuel ratio can be reduced by charging the iron ore generated by metallic iron into the blast furnace (see Non-Patent Document 2).
[0038]
In order to efficiently reduce the ore charged in the blast furnace using the reformed blast furnace gas as a reducing gas, it is necessary to react at 700 ° C. or higher, and it is necessary to raise the temperature of the reducing gas or the ore.
[0039]
The coke oven gas saved by using the reformed blast furnace gas as a hot blast stove fuel gas, a coke oven fuel gas or a fuel gas for power generation is partially burned with oxygen to generate a high-temperature reducing gas, which is then converted. By mixing high quality blast furnace gas, a reducing gas having a temperature required for reduction can be produced.
[0040]
It is also possible to use the combustion heat of woody biomass, which is a renewable energy, as the temperature rising energy of the reforming blast furnace gas.
[0041]
The calorific value is 650-850 kcal / Nm³When the blast furnace gas is used as a fuel gas for power generation, the calorific value is small. Therefore, the blast furnace gas is usually used as fuel for a boiler, and the steam produced by the boiler drives a steam turbine to generate power.
[0042]
However, as disclosed in Patent Document 3, the thermal efficiency of power generation by a boiler and a steam turbine is relatively low at 38 to 40%. Therefore, in Patent Document 3, coal as a boiler fuel is subjected to partial water gasification treatment to generate a calorific value of 1000 to 1500 kcal / Nm.³Gas is used as gas turbine fuel, and the gas is used as fuel for gas turbine to generate power. At the same time, combined cycle power generation combining gas turbine power generation with boiler and steam turbine power generation is performed to reduce power generation efficiency by about 46%. %.
[0043]
Therefore, as described in the present invention, the calorific value is 650 to 850 kcal / Nm.³Calorific value from blast furnace gas of 1000 kcal / Nm³Improving power generation efficiency by producing the above reformed blast furnace gas and performing combined cycle power generation combining gas turbine power generation using it as fuel for gas turbines and power generation using boilers and steam turbines Is done.
[0044]
If the power used in the steelworks is constant, the power generation efficiency is improved, and if the amount of reformed blast furnace gas used in the power plant is constant, the power generation increases and surplus power is generated, and the power can be sold outside.
[0045]
On the other hand, if the amount of power generation at the power plant is constant in accordance with the power used in the steelworks, the amount of reformed blast furnace gas used at the power plant will decrease, and the amount of reformed blast furnace gas will have a margin. This surplus reforming blast furnace gas can be newly used, and for example, CO 2 removal described below₂It can be used as energy required for the process.
[0046]
CO from blast furnace gas₂Removal of CO₂By using a chemical absorption method using an amine-based absorbing solution for the process, a large amount of gas can be efficiently treated.
[0047]
In the chemical absorption method, a blast furnace gas and an amine-based absorbing solution are brought into contact with each other at room temperature in an absorption tower to remove CO2 in the blast furnace gas.₂Absorbing CO2 into the absorbing solution;₂Is sent to a regeneration tower, where CO is absorbed.₂Is heated, and CO in the absorbing solution is heated.₂From the absorbing solution to regenerate the absorbing solution.
[0048]
The heating energy required to regenerate this absorbent is 2.8 to 3.0 MJ / kg-CO₂(See Non-Patent Document 4).
[0049]
A part or all of the fuel required as a source of this energy is supplied using surplus energy corresponding to the efficiency improvement obtained by using a high calorie reformed blast furnace gas at a steel mill, Utilizes unused waste sensible heat such as sintering machine exhaust gas, coke oven exhaust gas, hot blast oven exhaust gas, heating furnace exhaust gas, coke oven gas, converter gas, sinter, coke, blast furnace slag, and cooling water at steelworks Or by utilizing the heat of combustion of woody biomass,₂New release into the atmosphere can be suppressed.
[0050]
Further, when the reforming blast furnace gas is used in the reduction furnace as a reducing gas for iron ore, the sensible heat or combustion heat of the gas discharged from the reduction furnace and the sensible heat of₂It can be recovered and used effectively as thermal energy necessary for regeneration of the absorbing solution.
[0051]
Next, an embodiment of the present invention will be described. FIG. 1 is a conceptual diagram of the current use of blast furnace gas, coke oven gas and converter gas.
[0052]
A blast furnace gas 11, a coke oven gas 13 and a converter gas 14 are mixed and used as a fuel gas for heating the hot blast stove 2. The fuel gas for heating the coke oven 3 is a mixture of a blast furnace gas 11, a coke oven gas 13 and a converter gas 14.
[0053]
The blast furnace gas 11 excluding the amount used in the hot blast stove 2 and the coke oven 3 is used as a fuel gas for power generation in the power plant 7. The coke oven gas 13 and the converter gas 14 excluding the amounts used in the hot blast stove 2 and the coke oven 3 are mainly used as fuel gas in the heating furnace 8 or the like.
[0054]
Part of the coke 15 produced in the coke oven 3 is used in the sintering machine 4 and most is used in the blast furnace 1. In the blast furnace 1, the shortage of coke is supplemented by purchased coke 17. In the hot blast furnace 2, the air 19 and the oxygen 20 added thereto are heated, and the heated hot air 21 is sent to the blast furnace 1.
[0055]
The ore 18 produced by the sintering machine 4 and the ore 18 composed of lump ore and pellets are reduced and melted in the blast furnace 1 to become hot metal and slag 22. The blast furnace gas 11 discharged from the blast furnace top is recovered in the power 12 by the furnace pressure recovery power generation equipment 5.
[0056]
FIG. 2 shows the removal of CO from the blast furnace gas 11 by a chemical absorption method.₂Separation and removal of CO using energy 24 for regenerating the absorbent in process 9₂25 and calorific value 900 kcal / Nm³It is a conceptual diagram of the utilization form of reforming blast furnace gas, coke oven gas, and converter gas when the above-mentioned reforming blast furnace gas 23 is obtained.
[0057]
The entire amount of the reformed blast furnace gas 23 can be used as the fuel gas of the hot blast stove 2, and the coke oven gas and the converter gas, which are expensive high calorie gases required as the fuel gas of the hot stove 2 in the case of FIG. it can.
[0058]
The fuel gas of the coke oven 3 has a calorific value of 1000 kcal / Nm.³Because of the above requirements, it is necessary to mix a small amount of converter gas with the reforming blast furnace gas, but it is possible to save the coke oven gas and converter gas, which are expensive high-calorie gases, as compared with the case of FIG.
[0059]
However, in the hot blast stove 2 and the coke oven 3, the amount of gas used as blast furnace gas 11 increases, so that the power generation fuel gas required in the power plant 7 becomes insufficient, and the converter gas 14 is partially replenished. Need to be sent to the power plant 7.
[0060]
At this time, the fuel gas for power generation is a mixed gas of the reforming blast furnace gas 23 and the converter gas 14, and the calorific value of the mixed gas is 1000 kcal / Nm.³As described above, the fuel gas can be used as a gas turbine fuel gas.
[0061]
Therefore, by increasing the power generation equipment to the combined cycle power generation equipment, the power generation efficiency is improved, the surplus reformed blast furnace gas 26 can be obtained, and the purchase amount of expensive high calorie gas such as LPG and LNG can be reduced. It is possible, or alternatively, to use this excess reforming blast furnace gas 26 as CO2.₂It can be used for the energy 24 for absorbing liquid regeneration.
[0062]
FIG. 3 shows that the amount of oxygen 20 added to the air 19 is increased, the oxygen concentration of the hot air 21 is increased, the nitrogen concentration of the blast furnace gas 11 is reduced, and the calorific value is 1000 kcal / Nm.³The above reformed blast furnace gas 23 is obtained, and the resulting surplus coke oven gas 13 is blown into the blast furnace 1 from the tuyere to reduce the fuel ratio of the blast furnace 1, It is a key map of utilization form of gas and converter gas.
[0063]
Calorific value 1000 kcal / Nm³The above reforming blast furnace gas 23 can be used in its entirety as the fuel gas of the hot blast stove 2 and the fuel gas of the coke oven 3. In the case of FIG. It is possible to save the entire cost of the coke oven gas and converter gas, which are expensive and high calorie gases.
[0064]
By using the coke oven gas 13 in the blast furnace 1, the fuel ratio is reduced and the amount of expensive coke purchased can be reduced, thereby reducing costs. Further, by blowing the coke oven gas 13 into the blast furnace 1 from the tuyere, the calorific value and the generation amount of the blast furnace gas 11 increase, and as a result, the surplus reforming blast furnace gas 26 can be obtained.
[0065]
The surplus reforming blast furnace gas 26 contains CO 2₂It can be used for the energy 24 for absorbing liquid regeneration.
[0066]
FIG. 4 shows that the coke oven gas 23 and oxygen 27, which can be saved by using the reformed blast furnace gas 23 as the fuel gas for the hot blast furnace 2 and the fuel gas for the coke oven 3, are reacted in the partial combustion furnace 28 to produce a high-temperature reducing gas. The reduced iron 32 is obtained by using the reduced gas 30 whose temperature has been adjusted by mixing the reformed blast furnace gas 23 with the high-temperature reduced gas 29 in the reduced iron production reduction furnace 10. FIG. 2 is a conceptual diagram of a utilization form of a reforming blast furnace gas, a coke oven gas, and a converter gas when the fuel ratio of the blast furnace 1 is reduced by charging the blast furnace 1 with the blast furnace.
[0067]
By using the reduced iron 32 in the blast furnace 1, the fuel ratio is reduced, the amount of expensive coke used can be reduced, and the cost can be reduced.
[0068]
Further, by recovering the sensible heat and combustion heat of the reducing furnace exhaust gas 31 and the sensible heat of the reduced iron 32 in the reducing furnace 10 for reducing iron production, this energy is reduced to CO2.₂It can be used for the energy 24 for absorbing liquid regeneration.
[0069]
【Example】
Hereinafter, the blast furnace gas of the present invention is CO₂The method of removal and separation will be described in detail with reference to Comparative Examples and Examples 1, 2 and 3 shown in Tables 1 and 2.
[0070]
[Table 1]

[0071]
[Table 2]

[0072]
In Example 1, the heating value of the comparative example was 768 kcal / Nm.³From blast furnace gas to CO₂And calorific value 972 kcal / Nm³This is an example of producing a reformed blast furnace gas of the present invention.
[0073]
In Example 1, the calorific value of the reforming blast furnace gas was 900 kcal / Nm.³From the above, it is possible to use 431 Mcal / tp required for 1 ton of hot metal as hot air stove fuel gas for blast furnace blowing. The total amount of coke oven gas 63 Mcal / tp, which is an expensive high calorie gas used per ton, and the total amount of converter gas 17 Mcal / tp can be saved by replacing the reformed blast furnace gas. Was.
[0074]
In Example 1, the calorific value was 1000 kcal / Nm.³In order to obtain the above coke oven fuel gas, a converter gas of 19 Mcal / tp per ton of hot metal may be mixed with the reformed blast furnace gas. The total amount of 72 Mcal / tp of the coke oven gas, which is an expensive high calorie gas, and 44 Mcal / tp of the converter gas of 63 Mcal / tp can be saved by replacing the reformed blast furnace gas. Was.
[0075]
Further, in the first embodiment, a part of the coke oven gas and the converter gas saved is mixed with the reforming blast furnace gas to be used as a fuel gas for power generation for producing electric power required in another process.
[0076]
The fuel gas for power generation is 1000 kcal / Nm³As described in Patent Document 3, this calorific value is used to generate electric power by a gas turbine using this gas as a fuel for a gas turbine, and a combined turbine that combines gas turbine power generation with a boiler and steam turbine power generation. By performing the cycle power generation, the power generation efficiency was increased from 35% in the comparative example to 45% in Example 1.
[0077]
As a result, the fuel gas for power generation for producing 281 kWh of electric power to be used in another process per ton of hot metal could be saved by 153 Mcal / tp per ton of hot metal.
[0078]
The energy saved in Example 1 is CO 2₂It can be used for energy. In Example 1, CO2 removal from blast furnace gas per ton of hot metal₂The amount is 348Nm³/ Tp, and CO₂CO2 removal per unit volume₂Energy intensity is 1.36 Mcal / Nm³-CO₂(2.9 MJ / kg-CO₂), So CO removal per ton of hot metal₂The required energy is 473 Mcal / tp.
[0079]
In comparison with the comparative example, the energy saved in Example 1 of 153 Mcal / tp and the sensible heat recovered from the blast furnace slag of 80 Mcal / tp were removed from CO2.₂The energy to be newly procured by using it as energy for use may be 240 Mcal / tp per ton of hot metal.
[0080]
That is, in the first embodiment, the blast furnace gas₂Is 348 Nm³The increase in energy consumption per ton of hot metal, including 473 Mcal / tp required as energy for removal / tp removal, is 240 Mcal / tp relative to the comparative example, and is substantially CO 2₂Is 348 Nm³/ Tp was removed and separated at 240 Mcal / tp, and CO₂Substantial removal of CO per unit volume₂Energy intensity is 0.69Mcal / Nm³-CO₂Could be lowered.
[0081]
In Example 2, the blast furnace gas was₂By removing and separating the reformed blast furnace gas produced as a hot blast stove fuel gas and a coke oven fuel gas for blowing the blast furnace, by replacing the coke oven gas and the converter gas, which are expensive high calorie gases, The reduced coke oven gas is blown from the blast furnace tuyere to reduce the amount of expensive coke used.
[0082]
By injecting 215 Mcal / tp coke oven gas per ton of hot metal from the blast furnace tuyere and simultaneously increasing the oxygen enrichment rate from 2.5% of the comparative example to 5.6%, CO₂The calorific value of the reformed blast furnace gas produced by removing and separating is 1156 kcal / Nm³It became.
[0083]
As a result, it becomes possible to use all of the reformed blast furnace gas as the hot blast stove fuel gas and the coke oven fuel gas for the blast furnace blast, and the expensive blast furnace fuel gas and the coke oven fuel gas used for the blast furnace blast were used. The total amount of coke oven gas and converter gas, which are high calorie gases, was saved.
[0084]
Further, in Example 2, the calorific value was 1156 kcal / Nm.³As described in Patent Document 3, by using the reformed blast furnace gas as a fuel gas for power generation, the gas is used as a fuel for a gas turbine to generate power in a gas turbine, and gas turbine power generation and a boiler and By performing combined cycle power generation in combination with steam turbine power generation, the power generation efficiency can be increased from 35% in the comparative example to 45% in the second embodiment.
[0085]
As a result, fuel gas for power generation for producing electric power to be used in another process could be saved by 115 Mcal / tp per ton of hot metal. Also, due to the decrease in hot blast stove fuel used in the blast furnace process and the increase in the amount of blast furnace gas recovered, in Example 2 as compared with the comparative example, the energy consumption in the blast furnace process of 49 Mcal / tp per ton of hot metal was reduced. I was saved.
[0086]
The energy saved in Example 2 is₂It can be used for energy. In Example 2, CO2 removal from blast furnace gas per ton of hot metal₂The amount is 328Nm³/ Tp, and CO₂CO2 removal per unit volume₂Energy intensity is 1.36 Mcal / Nm³-CO₂Therefore, CO removal per ton of hot metal₂The required energy is 446 Mcal / tp.
[0087]
In comparison with the comparative example, the energy saved in Example 2 was 115 Mcal / tp and 49 Mcal / tp, and the sensible heat recovered from blast furnace slag of 80 Mcal / tp was removed from CO2.₂By using it for domestic energy, the energy to be newly procured was 202 Mcal / tp per ton of hot metal.
[0088]
Furthermore, the amount of expensive purchased coke can be saved by about 7 kg / tp, and a reduction in energy consumption in the blast furnace process due to a decrease in fuel ratio of 50 Mcal / tp is considered.₂The increase of the entire pig iron production energy including the energy is 152 Mcal / tp per ton of hot metal with respect to the comparative example.
[0089]
That is, in Example 2, the blast furnace gas per ton of hot metal₂Is 328 Nm³The increase in energy consumption per ton of hot metal, including 446 Mcal / tp required for the energy to separate / tp, is 152 Mcal / tp compared to the comparative example, and is substantially 328 Nm³/ Tp CO₂Was removed and separated at 152 Mcal / tp, and CO₂Substantial removal of CO per unit volume₂The unit energy consumption is 0.46 Mcal / Nm³-CO₂Could be lowered.
[0090]
Example 3 is based on the blast furnace gas₂By removing and separating the reformed blast furnace gas produced as a hot blast stove fuel gas and a coke oven fuel gas for blowing the blast furnace, by replacing the coke oven gas and the converter gas, which are expensive high calorie gases, The reduced iron produced by reducing iron ore using the saved coke oven gas and reformed blast furnace gas is used in a blast furnace to reduce the amount of expensive coke used.
[0091]
In Example 3, the calorific value of the reforming blast furnace gas was 976 kcal / Nm.³And the calorific value is 900 kcal / Nm³From the above, it is possible to use all of the reformed blast furnace gas as a hot blast furnace fuel gas for blast furnace blasting, thereby saving the total amount of coke oven gas and the total amount of converter gas, which are expensive high-calorie gases. Was.
[0092]
In the third embodiment, the calorific value is 1000 kcal / Nm.³In order to make the above-mentioned coke oven fuel gas, a converter gas of 16 Mcal / tp per ton of hot metal may be mixed with the reformed blast furnace gas. All of the expensive and high calorie gas, coke oven gas, and part of the converter gas were saved by replacing the reformed blast furnace gas.
[0093]
Further, in the third embodiment, a part of the saved converter gas is mixed with the reformed blast furnace gas to be used as a fuel gas for power generation for producing electric power required in another process. The fuel gas for power generation is 1000 kcal / Nm³As described in Patent Document 3, this calorific value is used to generate electric power by a gas turbine using this gas as a fuel for a gas turbine, and a combined turbine that combines gas turbine power generation with a boiler and steam turbine power generation. By performing the cycle power generation, the power generation efficiency was increased from 35% in the comparative example to 45% in Example 3.
[0094]
As a result, the fuel gas for power generation for producing 281 kWh of electric power to be used in another process per ton of hot metal could be saved by 153 Mcal / tp per ton of hot metal. In the blast furnace process, energy consumption increased by 15 Mcal / tp per ton of hot metal due to a decrease in blast furnace gas generation due to a decrease in fuel cost.
[0095]
In the reduced iron production process of Example 3, the coke oven gas was partially burned with oxygen to produce a high-temperature reduced gas, and the iron ore was reduced to the high-temperature reduced gas to produce metallic iron. A reforming blast furnace gas at a certain room temperature is mixed to produce a reducing gas adjusted to a temperature suitable for a reaction in a reducing furnace, and this is used to reduce reduced iron having a reduction rate of 85% to 40 kg per ton of hot metal. / Tp product.
[0096]
At this time, coke oven gas was used at 114 Mcal / tp, reforming blast furnace gas was used at 17 Mcal / tp, and oxygen was used at 5 Mcal / tp in terms of production energy.
[0097]
In addition, CO and H discharged from the reduction furnace₂The total of the latent heat and sensible heat recovered from the high-temperature exhaust gas containing the components and the sensible heat recovered from the high-temperature reduced iron discharged from the reduction furnace was 82 Mcal / tp. The energy consumption in this reduced iron production process, in which the recovered energy was subtracted from the energy used, was 59 Mcal / tp per ton of hot metal.
[0098]
That is, in Example 3, although there is an increase in energy consumption of 15 Mcal / tp per ton of hot metal in the blast furnace process and an increase in energy consumption of 59 Mcal / tp per ton of hot metal in the reduced iron production process, Since 153 Mcal / tp energy consumption per ton of hot metal could be saved by another process power production, 79 Mcal / tp energy consumption per 1 ton of hot metal could be saved in Example 3 in comparison with the comparative example. .
[0099]
The energy saved in Example 3 is the₂It can be used for energy. In Example 3, CO2 removal from blast furnace gas per ton of hot metal₂The amount is 339Nm³/ Tp, and CO₂CO2 removal per unit volume₂Energy intensity is 1.36 Mcal / Nm³-CO₂(2.9 MJ / kg-CO₂), So CO removal per ton of hot metal₂The required energy is 461 Mcal / tp.
[0100]
In comparison with the comparative example, the energy 79 Mcal / tp saved in Example 3 and the sensible heat recovered from the blast furnace slag 80 Mcal / tp were removed from CO 2.₂The energy to be newly procured by using it as energy for use may be 301 Mcal / tp per ton of hot metal.
[0101]
Furthermore, the amount of expensive coke used can be reduced by about 11 kg / tp compared to the comparative example, and considering the reduction of energy consumption in the blast furnace process due to the decrease in fuel ratio of 79 Mcal / tp, CO₂The total increase in pig iron production energy including energy is 222 Mcal / tp per ton of hot metal.
[0102]
That is, in the third embodiment, the blast furnace gas₂Is 339 Nm³The increase in energy consumption per ton of hot metal including 461 Mcal / tp required as energy for removing / tp removal is 222 Mcal / tp relative to the comparative example, which is substantially 339 Nm.³/ Tp CO₂Was removed and separated at 222 Mcal / tp, and CO₂Substantial removal of CO per unit volume₂Energy unit consumption is 0.66 Mcal / Nm³-CO₂Could be lowered.
[0103]
According to an embodiment of the present invention, in a steel mill, hot blast stove fuel gas for blast furnace blowing, coke oven fuel gas, and blast furnace gas discharged from the blast furnace top used as a part of the fuel gas for power generation use CO2.₂To produce a reformed blast furnace gas with a high calorific value, and use this as all or a part of the hot blast stove fuel gas or coke oven fuel gas for blowing the blast furnace, thereby increasing the cost of high calorie gas. It can be used as a fuel gas for power generation that can increase the power generation efficiency by saving coke oven gas and converter gas, and can be used to inject coke oven gas into the blast furnace to reduce the amount of expensive coke purchased. To produce reduced iron and put it into a blast furnace to reduce the amount of expensive coke purchased and CO as a measure to prevent global warming₂It has been shown that an effective utilization method is possible such that the energy required for the removal and separation of methane can be substantially reduced.
[0104]
【The invention's effect】
As described above, according to the present invention, CO2 is converted from blast furnace gas.₂The production of reformed blast furnace gas from which gas has been removed and separated, and the effective use of the reformed blast furnace gas, coke oven gas and converter gas at the steel works, enables the improvement of energy use efficiency, and enables industrial and global It can be expected to have a useful effect in preventing global warming.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a conceptual diagram showing a current utilization mode of a blast furnace gas, a coke oven gas, and a converter gas.
FIG. 2 is a conceptual diagram showing a utilization mode of a reforming blast furnace gas, a coke oven gas, and a converter gas according to the present invention.
FIG. 3 is a conceptual diagram showing a use form of a reforming blast furnace gas, a coke oven gas, and a converter gas when a coke oven gas is blown into a blast furnace according to the present invention.
FIG. 4 is a conceptual diagram showing a utilization mode of a reforming blast furnace gas, a coke oven gas, and a converter gas when reducing iron is charged into a blast furnace according to the present invention.
[Explanation of symbols]
1. Blast furnace
2. Hot air stove
3. Coke oven
4: Sintering machine
5 ... Furnace top pressure recovery power generation equipment
6 ... Converter
7 ... Power station
8. Heating furnace, etc.
9 ... CO2 removal₂process
10. Reduced iron production reduction furnace
11 Blast furnace gas
12: Furnace top pressure recovery power
13 ... Coke oven gas
14. Converter gas
15 ... Coke
16 ... Pulverized coal
17 ... Purchase coke
18 ore
19 ... air
20 ... oxygen
21 ... Hot air
22 ... Hot metal and slag
23 ... Reforming blast furnace gas
24 ... CO₂Absorbent regeneration energy
25: Separation and removal CO₂
26 ... Excess reforming blast furnace gas
27 ... oxygen
28 Partial combustion furnace
29 High-temperature reducing gas
30 ... Reducing gas
31: Reduction furnace exhaust gas
32 ... Reduced iron

Claims (7)

CO ₂ is removed and separated from blast furnace gas of less than 900 kcal / Nm ³ discharged from the blast furnace furnace top to produce a reformed blast furnace gas of 900 kcal / Nm ³ or more. coke oven fuel gas, and any one or are used as two or more of the fuel gas 900 kcal / Nm ³ less than blast furnace gas, 2000 kcal / Nm ³ or more coke oven gas power generation fuel gas, converter gas , And a method of using blast furnace gas characterized by replacing part or all of one or more of LPG. Oxygen is added to the blast furnace blast air to reduce the N ₂ concentration in the blast furnace gas to 50% or less, and CO ₂ is removed from the blast furnace gas and separated to produce a reformed blast furnace gas of 1000 kcal / Nm ³ or more. The blast furnace gas of less than 900 kcal / Nm ^{3, wherein the} reforming blast furnace gas is used as one or more of a hot blast stove fuel gas, a coke oven fuel gas, and a fuel gas for power generation, A method of using a blast furnace gas characterized by substituting a part or all of one or more of coke oven gas, converter gas, and LPG of Nm ³ or more. 3. The method according to claim 1, wherein a part or all of the coke oven gas is blown from a blast furnace tuyere. 900 kcal / Nm ³ or more reformed blast furnace gas produced by removing and separating CO ₂ from blast furnace gas of less than 900 kcal / Nm ³ discharged from the blast furnace furnace top, or oxygen is added to blast furnace blowing air and oxygen is added to the blast furnace gas. with lowering of _{N 2} concentrations below 50%, and 1000 kcal / Nm ³ or more in the reformed blast furnace gas produced by removing separating CO ₂ from the blast furnace gas, some or all of the coke oven gas, iron ore reducing A method of using blast furnace gas, which is used in a reduction furnace as a reducing gas for use. The method according to claim 4, wherein the reduced iron produced in the reduction furnace is charged into a blast furnace. The removal separation of the CO ₂ gas absorption method, cryogenic separation method, a gas adsorption method, and, blast furnace according to any one of claims 1 to 5, wherein the performing by either membrane separation method How to use gas. The method according to claim 6, wherein the gas absorption method is a chemical absorption method using an amine-based absorption liquid.

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