JP2015174934A - Method of producing coke for plast furnace - Google Patents

Method of producing coke for plast furnace Download PDF

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JP2015174934A
JP2015174934A JP2014053093A JP2014053093A JP2015174934A JP 2015174934 A JP2015174934 A JP 2015174934A JP 2014053093 A JP2014053093 A JP 2014053093A JP 2014053093 A JP2014053093 A JP 2014053093A JP 2015174934 A JP2015174934 A JP 2015174934A
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JP6241336B2 (en
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孝 有馬
Takashi Arima
孝 有馬
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Nippon Steel Corp
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Nippon Steel and Sumitomo Metal Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a method of producing coke for blast furnaces which provides coke having large grain sizes while keeping coke strength by adding a binding material.SOLUTION: A method of producing coke for blast furnaces comprises charging a coal blend containing low-coalification-degree coals of an average reflectance of 0.65-0.9% and high-coalification-degree coals of an average reflectance of higher than 0.9% into a coke oven, with 5-15 mass%, in terms of the ratio to brand coals contained in the low-coalification-degree coal with respect to the average reflectance, of a binding material added, heating the brand coals and the binding material to a temperature equal to or higher than the softening point of the binding material and equal to or lower than 350°C and kneading, blending remaining coals of the coal blend and charging into the coke oven.

Description

本発明は、高炉用コークスの製造方法に関し、詳しくは、コークス強度を維持しながら、大きな粒径のコークスを得ることができる高炉用コークスの製造方法に関する。   The present invention relates to a method for producing coke for blast furnace, and more particularly, to a method for producing coke for blast furnace that can obtain coke having a large particle size while maintaining coke strength.

一般に、製鉄プロセスでは、高炉の上部から焼結鉱や鉄鉱石などの鉄含有原料とコークスとを交互に装入し、高炉の下部から熱風を吹き込むことで、コークスをガス化して一酸化炭素や水素などを含んだ高温ガスを発生させて、鉄含有原料を加熱溶融しつつ、還元反応により銑鉄を得る。   In general, in the steelmaking process, iron-containing raw materials such as sintered ore and iron ore and coke are alternately charged from the upper part of the blast furnace, and hot air is blown from the lower part of the blast furnace to gasify the coke to carbon monoxide and A hot gas containing hydrogen or the like is generated, and pig iron is obtained by a reduction reaction while heating and melting the iron-containing raw material.

このように高炉用コークスには、鉄含有原料を加熱溶融するための熱源、鉄含有原料を還元して鉄分を取り出すための還元材、及び、高炉中での高温ガスや溶けた鉄の通路を確保するための通気・通液材としての役割がある。従って、高炉内での通気・通液が確保されるようにするために、高炉用コークスは高強度であると共に、粒径が大きいことが有利である。   Thus, the blast furnace coke has a heat source for heating and melting the iron-containing raw material, a reducing material for reducing the iron-containing raw material to extract iron, and a passage of high-temperature gas or molten iron in the blast furnace. It has a role as a ventilation and liquid passing material to ensure. Accordingly, in order to ensure ventilation and liquid passage in the blast furnace, it is advantageous that the blast furnace coke has high strength and a large particle size.

通常、コークスを製造する際には、銘柄の異なる石炭を複数組み合わせて配合炭とし、コークス炉において高温で長時間乾留することで、高炉で要求されるような所望のコークス強度を有するコークスを得るようにしている。ところが、製造されるコークスの粒度は、用いる石炭の特性によっても変わってしまう。特に、近年では、非微粘結炭のような安価な石炭の使用量を増やすことで、コークス製造のコストを抑えるようにするが、品質が劣る石炭を配合することで、コークス粒度は低下する傾向にある。   Usually, when coke is produced, a combination of different brands of coal is blended into a blended coal, and coke having a desired coke strength as required in a blast furnace is obtained by high-temperature dry distillation in a coke oven. I am doing so. However, the particle size of the coke produced varies depending on the characteristics of the coal used. In particular, in recent years, the cost of coke production is reduced by increasing the amount of inexpensive coal used, such as non-slightly caking coal, but the coke particle size is reduced by blending coal with poor quality. There is a tendency.

そこで、従来、配合炭に粉コークスを添加することで、得られるコークスの粒径を制御する方法や(特許文献1参照)、粉コークスと共に石油系ピッチを配合炭に添加する方法(特許文献2参照)が知られている。しかしながら、配合炭に粉コークスを添加することによって、コークス粒度は拡大するものの、コークス強度は逆に低下してしまう。特許文献2のように、石油系ピッチなどの添加材を加えることで、粉コークス添加によるコークス強度の低下をある程度抑制することはできるが、高い強度を有して粒径を拡大させたコークスを安定して製造するのは難しい。   Therefore, conventionally, a method of controlling the particle size of coke obtained by adding powdered coke to blended coal (see Patent Document 1), and a method of adding petroleum-based pitch to blended coal together with powdered coke (Patent Document 2). See). However, by adding powdered coke to the blended coal, the coke particle size increases, but the coke strength decreases. As in Patent Document 2, by adding additives such as petroleum-based pitch, the reduction in coke strength due to the addition of powdered coke can be suppressed to some extent, but coke with high strength and expanded particle size can be obtained. It is difficult to manufacture stably.

また、通常タールよりも軟化点が高いタール重質留分、ソフトピッチ、石油ピッチ等の粘結材を配合炭に対する割合で2〜10質量%添加することで、粒径が大きなコークスを製造する方法も知られている(特許文献3参照)。この方法は、上記のような粘結材を添加して配合炭の再固化温度を上昇させることにより、コークス炉内での収縮量を低減させ、また、軟化溶融過程での石炭粒子同士の接着を高めて、亀裂の発生や伝播を抑制して得られるコークス粒径の向上を図るものである。   Moreover, coke with a large particle diameter is manufactured by adding caking materials, such as a heavy tar fraction with a softening point higher than tar, soft pitch, petroleum pitch, etc. in the ratio with respect to a combination charcoal. A method is also known (see Patent Document 3). In this method, the amount of shrinkage in the coke oven is reduced by adding a binder as described above to increase the resolidification temperature of the blended coal, and the coal particles are bonded to each other in the softening and melting process. In order to improve the coke particle size obtained by suppressing the generation and propagation of cracks.

特開昭60−69192号公報JP 60-69192 A 特開平6−17056号公報JP-A-6-17056 特開2008−120973号公報JP 2008-120973 A

上述したように、コークス強度を高めたり、粒径の大きなコークスを製造する上で、配合炭に粘結材を添加することは知られている。しかしながら、粘結材がもたらすコークスの強度を維持しながら、粒径を拡大させることについて、これまでに検討はなされていない。   As described above, it is known to add a caking additive to blended coal in order to increase coke strength or produce coke having a large particle size. However, no investigation has been made so far on increasing the particle size while maintaining the strength of coke provided by the binder.

すなわち、従来の高炉用コークスの製造方法では、配合炭に粘結材を添加してコークス炉に装入し、乾留してコークスを製造している。例えば上記特許文献2及び3においては、いずれも配合炭に対する割合で10質量%以下で粘結材を添加し(特許文献2の段落0021、特許文献3の段落0063参照)、コークス炉に装入してコークスを得るようにしている。ところが、本発明者らが得た知見によれば、複数銘柄の石炭を含む配合炭における粘結材の働きに着目すると、添加材によるコークス強度を維持しながら、粒径を拡大させることについては、更に改善の余地があることが分かった。   That is, in a conventional method for producing coke for blast furnace, a caking agent is added to blended coal, charged into a coke oven, and dry-distilled to produce coke. For example, in Patent Documents 2 and 3, the binder is added at a ratio of 10% by mass or less with respect to the blended coal (see Paragraph 0021 of Patent Document 2 and Paragraph 0063 of Patent Document 3) and charged into the coke oven. And try to get coke. However, according to the knowledge obtained by the present inventors, focusing on the action of the caking agent in the blended coal containing multiple brands of coal, while maintaining the coke strength by the additive, I found that there was room for further improvement.

そこで、本発明の目的は、粘結材の添加によって、コークス強度を維持しながら、粒径の大きなコークスを得ることができる高炉用コークスの製造方法を提供することにある。   Then, the objective of this invention is providing the manufacturing method of the coke for blast furnaces which can obtain coke with a large particle size, maintaining coke intensity | strength by addition of a caking additive.

本発明者らは、高炉用コークスの製造における粘結材の添加について詳細な検討を重ねた結果、従来のように、配合炭に対して粘結材をまとめて添加するのではなく、所定の粘結性を有する低石炭化度炭に粘結材を選択的に添加するようにし、しかも、添加対象の低石炭化度炭に対する割合で粘結材の添加量を決定するようにすることで、コークス強度を維持しながら、粒径の大きなコークスが得られるようになることを見出し、本発明を完成させた。   As a result of repeated detailed studies on the addition of the binder in the production of blast furnace coke, the present inventors do not collectively add the binder to the blended coal as in the past. By selectively adding a caking additive to low-carbonized coal with caking properties, and determining the amount of caking additive added in proportion to the low-carbonized coal to be added The present inventors have found that coke having a large particle diameter can be obtained while maintaining coke strength.

すなわち、本発明の要旨は以下に記したとおりである。
(1)少なくとも平均反射率が0.65%以上0.9%以下の低石炭化度炭と平均反射率が0.9%超の高石炭化度炭とを配合した配合炭をコークス炉に装入して、高炉用コークスを製造する方法において、平均反射率が前記の低石炭化度炭の範囲に含まれる銘柄の石炭に対する割合で5質量%以上15質量%以下の粘結材が添加された状態で、該銘柄の石炭と粘結材とを粘結材の軟化点以上350℃以下の範囲に加熱して混練したうえで、配合炭を構成する残りの石炭と配合して、コークス炉に装入することを特徴とする高炉用コークスの製造方法。
(2)平均反射率が前記の低石炭化度炭の範囲に含まれる石炭が複数銘柄存在し、そのうちの少なくとも1つ又は2つ以上の銘柄の石炭について、1銘柄の石炭に対する割合で5質量%以上15質量%以下の粘結材が添加された状態で加熱し混練して、配合炭を構成する残りの石炭と配合する(1)に記載の高炉用コークスの製造方法。
(3)粘結材を添加する前記の低石炭化度炭が、JIS M8801による最高流動度が10ddpm以上である(1)又は(2)に記載の高炉用コークスの製造方法。
(4)粘結材の揮発分が60質量%以下である(1)〜(3)のいずれかに記載の高炉用コークスの製造方法。
(5)粘結材が石炭系粘結材である(1)〜(4)のいずれかに記載の高炉用コークスの製造方法。
(6)粘結材が添加された状態で加熱し混練した低石炭化度炭を10mm以下の大きさに解砕した後、配合炭を構成する残りの石炭と配合する(1)〜(5)のいずれかに記載の高炉用コークスの製造方法。
That is, the gist of the present invention is as described below.
(1) A blended coal containing at least an average reflectance of 0.65% or more and 0.9% or less of low-coalized coal and an average reflectance of more than 0.9% of high-coalized coal is used as a coke oven. In the method of charging and producing coke for blast furnace, a caking agent having an average reflectance of 5% by mass or more and 15% by mass or less in terms of the ratio of brands included in the range of the low-coalizing coal is added. In this state, the coal of the brand and the binder are heated and kneaded in the range of the softening point of the binder to 350 ° C. or less, and then blended with the remaining coal constituting the blended coal. A method for producing coke for blast furnace, which is charged into a furnace.
(2) There are a plurality of coals whose average reflectivity is included in the range of the above-mentioned low-coalized coal, and at least one or more of the coals are 5 masses in proportion to one brand of coal. The method for producing coke for blast furnace according to (1), wherein the mixture is heated and kneaded in a state where a binder of not less than 15% and not more than 15% by mass is added, and blended with the remaining coal constituting the blended coal.
(3) The method for producing coke for blast furnace according to (1) or (2), wherein the low-coalizing coal to which the caking additive is added has a maximum fluidity of 10 ddpm or more according to JIS M8801.
(4) The method for producing coke for blast furnace according to any one of (1) to (3), wherein a volatile content of the binder is 60% by mass or less.
(5) The method for producing coke for blast furnace according to any one of (1) to (4), wherein the binder is a coal-based binder.
(6) After pulverizing the low-coalizing coal heated and kneaded in a state where the caking additive is added to a size of 10 mm or less, it is blended with the remaining coal constituting the blended coal (1) to (5 ) A method for producing coke for blast furnace as described in any of the above.

本発明によれば、所定の粘結性を有する低石炭化度炭に対して選択的に粘結材を添加することで、コークス強度を維持しながら、粒径の大きなコークスを得ることができるようになる。例えば、同量の粘結材を使用する場合で比較しても、本発明による方法で製造したコークスは、従来のように配合炭に粘結材を添加して得たコークスよりも強度の維持と粒径拡大との両立が図られ、粘結材の働きを効率良く引き出すことができる。そのため、本発明の方法は、粘結炭に比べて品質の劣る安価な石炭の増使用が進む高炉用コークスの製造において、極めて有用である。   According to the present invention, coke having a large particle size can be obtained while maintaining coke strength by selectively adding a caking agent to low-carbonized coal having a predetermined caking property. It becomes like this. For example, even when using the same amount of caking material, the coke produced by the method of the present invention maintains strength compared to coke obtained by adding caking material to blended coal as in the past. And particle size expansion can be achieved, and the action of the binder can be efficiently extracted. For this reason, the method of the present invention is extremely useful in the production of blast furnace coke in which the use of inexpensive coal, which is inferior in quality compared with caking coal, proceeds.

図1は、配合炭における粘結材の添加の様子を模式的に示す図である。FIG. 1 is a diagram schematically showing the state of addition of a binder in blended coal. 図2は、粘結材の添加によるコークスの強度指数と粒度の改善の様子を表す概念図である。FIG. 2 is a conceptual diagram showing how coke strength index and particle size are improved by the addition of a binder. 図3は、コークス製造試験1〜4で得られた各試験用コークスの平均粒度と低石炭化度炭Aの配合率との関係を示すグラフである。FIG. 3 is a graph showing the relationship between the average particle size of each test coke obtained in the coke production tests 1 to 4 and the blending ratio of the low-coalizing coal A. 図4は、コークス製造試験1〜4で得られた各試験用コークスのドラム強度指数と低石炭化度炭Aの配合率との関係を示すグラフである。FIG. 4 is a graph showing the relationship between the drum strength index of each test coke obtained in the coke production tests 1 to 4 and the blending ratio of the low-coalizing coal A.

以下、本発明について詳細に説明する。
先ず、本発明では、少なくとも平均反射率が0.65%以上0.9%以下の低石炭化度炭と平均反射率が0.9%超の高石炭化度炭とを配合した配合炭をコークス炉に装入して、高炉用コークスを製造する方法として、図1(1)に示したように、平均反射率が0.65%以上0.9%以下の低石炭化度炭と平均反射率が0.9%超の高石炭化度炭とを配合した際に、平均反射率が0.65%以上0.9%以下の低石炭化度炭側に粘結材を添加して、コークスを得る場合(すなわち、平均反射率が0.65%未満の石炭を配合しない場合)を例に挙げて説明する。
Hereinafter, the present invention will be described in detail.
First, in the present invention, a blended coal comprising at least an average reflectance of 0.65% or more and 0.9% or less of low coalified coal and an average reflectance of more than 0.9% of high coalified coal. As shown in FIG. 1 (1), a method for producing coke for a blast furnace by charging in a coke oven and an average reflectance of 0.65% or more and 0.9% or less of low coal degree coal and average When blending with high-coalized coal with a reflectance of over 0.9%, add a caking additive to the low-carbonized coal side with an average reflectance of 0.65% or more and 0.9% or less. The case where coke is obtained (that is, the case where coal having an average reflectance of less than 0.65% is not blended) will be described as an example.

本発明者らのこれまでの知見によれば、コークス粒度を拡大するには、強度指数(DI150 15)を改善する場合と比較して多量の粘結材を添加する必要がある。ここで、強度指数(DI150 15)は、JIS K 2151に基づき測定することができる。
ところが、図2に示した概念図のように、粘結材の添加量に対して、コークス粒度の拡大と強度指数の向上とは必ずしも一致せず、添加材を多く添加してコークス粒度をより大きくすると、逆にコークス強度は低下してしまうことが新たに判明した。これは、コークス炉に装入した装入炭の揮発分が増えて、コークスの気孔率が上昇してコークスの強度指数が低下するためと考えられる。
According to the present inventors' previous knowledge, in order to expand the coke particle size, it is necessary to add a large amount of binder compared with the case where the strength index (DI 150 15 ) is improved. Here, the strength index (DI 150 15 ) can be measured based on JIS K 2151.
However, as shown in the conceptual diagram of FIG. 2, the increase in the coke particle size and the improvement in the strength index do not always coincide with the amount of the caking additive added. On the contrary, it has been newly found that the coke strength decreases when the value is increased. This is considered to be because the volatile matter of the charging coal charged into the coke oven increases, the porosity of the coke increases, and the strength index of the coke decreases.

そこで、本発明の高炉用コークスの製造方法では、従来のように配合炭に粘結材を添加するのではなく、所定の粘結性を有する低石炭化度炭に対して、粘結材を選択的に添加することにより、コークス強度を維持しながら、粒径の大きなコークスを得ることができることを新たに見出した。
詳細には、本発明者らは、粘結材添加によるコークス粒度の拡大効果は、平均反射率が0.65%以上0.9%以下の低石炭化度炭の場合が大きいことを見出した。
Therefore, in the method for producing coke for blast furnace according to the present invention, rather than adding a caking additive to the blended coal as in the past, a caking additive is used for a low-coalizing coal having a predetermined caking property. It was newly found that by adding selectively, coke having a large particle size can be obtained while maintaining coke strength.
Specifically, the present inventors have found that the effect of expanding the coke particle size due to the addition of the binder is large in the case of low-rank coal having an average reflectance of 0.65% to 0.9%. .

粘結材添加によるコークス粒度の拡大効果は、平均反射率が0.65以上0.9以下の低石炭化度炭の場合が大きい理由については、以下の様に推察される。
石炭をコークス炉で乾留してコークスを得る際、一般に、石炭は400℃前後から軟化し、450〜500℃で再固化してセミコークスになる。セミコークスはそれ以降も加熱されコークスになるが、その過程で収縮する。この収縮の歪によりコークスに亀裂が発生すると考えられる。なかでも、平均反射率が0.9以下の低石炭化度炭のセミコークスは収縮率が大きく、コークスに亀裂が多く生成するため、コークス炉からの押し出しや搬送過程での衝撃等によって割れが発生し易く、得られるコークスの粒度が低下する原因になる。
The reason why the coke particle size expansion effect due to the addition of the binder is large in the case of low-coalized coal having an average reflectance of 0.65 to 0.9 is presumed as follows.
When coal is obtained by coking in a coke oven, generally the coal softens from around 400 ° C. and resolidifies at 450 to 500 ° C. to become semi-coke. Semi-coke is subsequently heated to coke, but shrinks in the process. It is thought that cracks are generated in the coke due to this shrinkage strain. Among them, semi-coke of low-carbonized coal with an average reflectivity of 0.9 or less has a large shrinkage rate and many cracks are generated in the coke. Therefore, cracking occurs due to extrusion from the coke oven or impact during the conveyance process. It is easy to generate | occur | produce and causes the particle size of the obtained coke to fall.

一方で、平均反射率が0.65%未満の石炭は粘結性がほとんどなく、粘結材との相互作用が弱いため、得られるコークスの粒度拡大効果は望めない。
そのため、本発明では、平均反射率が0.65%以上0.9%以下の低石炭化度炭に対して粘結材を選択的に添加することで、この低石炭化度炭の再固化後の収縮率を低下させて、上記のような亀裂生成を抑制することができる。平均反射率が0.9%超の高石炭化度炭は、そもそも低石炭化度炭に比べて収縮率が小さいため、粘結材を添加することによってその収縮率を低下させる効果に乏しい。
従って、亀裂抑制の効果の高い低石炭化度炭(平均反射率が0.65%以上0.9%以下)にのみ粘結材を添加し、その効果の低い高石炭化度炭や、平均反射率が0.65%未満の石炭には粘結材を添加しないようにすれば、粘結材の働きが効率良く得られるだけでなく、気孔率上昇に伴うコークス強度指数の低下を防ぐことができると考えられる。
On the other hand, coal having an average reflectance of less than 0.65% has almost no caking property and has a weak interaction with the caking material, so that the effect of expanding the particle size of the obtained coke cannot be expected.
Therefore, in the present invention, the low-coalizing coal is re-solidified by selectively adding a caking additive to the low-coalizing coal having an average reflectance of 0.65% or more and 0.9% or less. It is possible to reduce the subsequent shrinkage and suppress the generation of cracks as described above. Highly coalified coal with an average reflectance of more than 0.9% has a smaller shrinkage rate than low-coalized coals in the first place, so that the effect of lowering the shrinkage rate by adding caking additive is poor.
Therefore, a caking additive is added only to low-coalizing coal (average reflectance is 0.65% or more and 0.9% or less) with high crack-suppressing effect. If the caking agent is not added to coal with a reflectivity of less than 0.65%, not only can the caking agent function efficiently, but also prevent the coke strength index from decreasing with increasing porosity. It is thought that you can.

なお、石炭の平均反射率とは、後述する実施例の内容を含めて、ISO 7405−5の”Methods for the petrographic analysis of bituminous coal and anthracite”記載の方法で測定されるビトリニットの平均ランダム反射率(以下、Roと略称する場合がある)を意味する。   The average reflectance of coal is the average random reflectance of vitrinite measured by the method described in “Methods for the petrographic analysis of bituminous coal and anthracite” in ISO 7405-5, including the contents of Examples described later. (Hereinafter may be abbreviated as Ro).

また、粘結材の添加量については、添加対象の低石炭化度炭に対する割合(粘結材/対象低石炭化度炭)で5質量%以上15質量%以下、好ましくは7質量%以上12質量%以下となるようにする。添加対象の低石炭化度炭に対する粘結材の割合が5質量%未満では、当該低石炭化度炭の改質反応による収縮率の低下が十分に起こらない場合があり、反対に15質量%を超えて添加すると、粘結材由来の揮発分が増えてコークスの気孔率が上昇し、かえってコークス強度を低下させてしまうためである。   Moreover, about the addition amount of caking additive, it is 5 mass% or more and 15 mass% or less by the ratio with respect to the low coalification degree coal of addition object (caking material / object low coalification degree coal), Preferably 7 mass% or more 12 The mass should be not more than%. When the ratio of the caking additive to the low-carbonized coal to be added is less than 5% by mass, the shrinkage rate may not be sufficiently reduced due to the reforming reaction of the low-carbonized coal. This is because the volatile matter derived from the binder increases and the porosity of the coke increases, and the coke strength decreases.

ここで、粘結材としては公知のものを使用でき、例えば、コールタール、コールタールを蒸留して得られる軟ピッチや硬ピッチ、石油系のアスファルト、アスファルトを熱処理、抽出等して得られるピッチ等のような瀝青物を用いることができる。なかでも、コールタールやコールタールを蒸留して得られる軟ピッチ、硬ピッチ等の石炭系粘結材であれば、石炭との相互作用が強いため、改質反応によって低石炭化度炭の収縮率を低下させる効果が大きい。   Here, known binders can be used, for example, coal tar, soft pitch or hard pitch obtained by distillation of coal tar, petroleum-based asphalt, pitch obtained by heat treatment, extraction, etc. Bituminous materials such as can be used. In particular, coal-based caking materials such as coal pitch and coal pitch obtained by distilling coal tar have a strong interaction with coal, so the shrinkage of low-coalizing coal is reduced by the reforming reaction. The effect of reducing the rate is great.

また、上述したように、粘結材の揮発分が高いと、コークス炉に装入する装入炭の揮発分が高くなり、コークス収率が低下するため、コークスの気孔率が上昇してコークス強度が低下することがある。特に、低石炭化度炭は揮発分が高いため、低石炭化度炭を多量に配合すると、コークス炉装入炭の揮発分が高くなる傾向がある。そのため、コークス炉装入炭の揮発分の上昇を防ぐ必要がある場合には、揮発分が60質量%以下の粘結材を使用するのが望ましい。   In addition, as described above, when the volatile content of the binder is high, the volatile content of the charging coal charged in the coke oven increases and the coke yield decreases, so the coke porosity increases and the coke increases. The strength may decrease. In particular, since low-carbon coal has a high volatile content, when a large amount of low-carbon coal is blended, the volatile content of coke oven charging coal tends to increase. Therefore, when it is necessary to prevent an increase in the volatile content of the coke oven charging coal, it is desirable to use a binder having a volatile content of 60% by mass or less.

また、本発明において、配合炭として、平均反射率が0.65%以上0.9%以下の低石炭化度炭の範囲に含まれる石炭を複数銘柄で含む場合には、そのうちの少なくとも1つ又は2つ以上の銘柄の石炭に対して粘結材を添加してもよい。すなわち、平均反射率が0.65%以上0.9%以下の低石炭化度炭に分類される銘柄の石炭のうちの少なくとも1種について、1銘柄の石炭に対する割合で5質量%以上15質量%以下の粘結材を添加してもよい。   Moreover, in this invention, when coal included in the range of the low coalification degree coal with an average reflectance of 0.65% or more and 0.9% or less is included as a blended coal, at least one of them is included. Or you may add a caking additive with respect to two or more brands of coal. That is, 5% by mass or more and 15% by mass with respect to at least one type of coal classified as low-coalized coal having an average reflectance of 0.65% to 0.9%. % Or less of a caking additive may be added.

例えば、図1(2)には、7つの銘柄の石炭を配合した配合炭であって、そのうち石炭a〜aが平均反射率0.65%以上0.9%以下の低石炭化度炭、石炭b〜bが平均反射率0.9%超の高石炭化度炭である例を示している。ここで、粘結材の添加対象となり得る低石炭化度炭(0.65%≦Ro≦0.9%)はa〜aの3銘柄であるが、この例では、石炭a及びaに対してそれぞれ粘結材を添加する場合を示している(すなわち、高石炭化度炭b〜bと共に低石炭化度炭aが、配合炭を構成する残りの石炭である)。その際の粘結材の添加量は、石炭aに対して5質量%以上15質量%以下とすると共に、石炭aに対しても5質量%以上15質量%以下となるようにしている。また、石炭a〜aのなかから粘結材を添加するものを選択するにあたっては、配合比率が多いものを優先したり、平均反射率がより低いものを優先するようにするのが好適である。勿論、石炭a〜aのいずれか1つに粘結材を添加するようにしてもよく、石炭a〜aの全てに対して、それぞれ所定の割合で粘結材を添加するようにしてもよい。なお、本発明においては、配合炭を構成するにあたり、平均反射率が0.65%未満の石炭を含めるようにしてもよい。但し、その場合には、粘結材を添加する対象には含めず、配合炭を構成する残りの石炭として扱う。 For example, in FIG. 1 (2), seven a coal coal blend obtained by blending stock, of which coal a 1 ~a 3 low coal degree of average reflectance 0.65% to 0.9% or less coal, coal b 1 ~b 4 indicates an example is a high coalification degree charcoal 0.9 percent average reflectance. Here, low-coalizing coal (0.65% ≦ Ro ≦ 0.9%) that can be added to the binder is three brands a 1 to a 3 , but in this example, for coal a 1 and a 2 shows a case of adding each caking Te (i.e., Takaishi-carbonization coal b 1 ~b low coalification degree coal a 3 with 4, the remaining coal constituting the coal blend). In this case, the amount of the binder is 5% by mass to 15% by mass with respect to the coal a 1 and 5% by mass to 15% by mass with respect to the coal a 2 . . Moreover, in selecting the one of adding a caking additive from among coal a 1 ~a 3 is or give priority to those often compounding ratio, suitable to such priority to an average reflectance lower It is. Of course, the caking additive may be added to any one of the coals a 1 to a 3 , and the caking additive may be added to each of the coals a 1 to a 3 at a predetermined ratio. It may be. In the present invention, coal having an average reflectance of less than 0.65% may be included in composing the blended coal. However, in that case, it is not included in the target to which the caking additive is added, and is treated as the remaining coal constituting the blended coal.

また、本発明においては、粘結材を添加する低石炭化度炭として、JIS M8801による最高流動度が10ddpm以上であると、石炭の溶融性が向上するため好ましい。平均反射率が0.65%以上0.9%以下であって、かつ、最高流動度が10ddpm以上の低石炭化度炭であると、粘結材との相互作用によるコークスの粒度拡大効果をより確実に得ることができる。なお、この最高流動度については、後述の実施例を含めて、JIS M8801に記載の流動性試験方法(ギーセラープラストメータ法)により求められるものである。   In the present invention, as the low-coalizing coal to which the caking additive is added, it is preferable that the maximum fluidity according to JIS M8801 is 10 ddpm or more because the coal meltability is improved. If the average reflectivity is 0.65% or more and 0.9% or less and the low fluidity coal has a maximum fluidity of 10 ddpm or more, the effect of expanding the particle size of coke due to the interaction with the binder is obtained. It can be obtained more reliably. The maximum fluidity is determined by the fluidity test method (Gieseller Plastometer method) described in JIS M8801, including the examples described later.

本発明において、粘結材を添加する低石炭化度炭については、粘結材が添加された状態で、粘結材の軟化点以上かつ350℃以下に加熱して混練することで、改質反応の対象となる石炭に粘結材を付着させるようにする。粘結材を石炭に付着させるには、粘結材の軟化点以上に加熱する必要があるが、350℃より高い温度に加熱すると、石炭の劣化(熱分解反応)が進行してしまうおそれがある。混練の手段としては特に制限はなく、例えば、二軸混練機やパン型混練機を用いるなど、公知の手法を採用することができる。また、粘結材が添加された状態で加熱・混練されればよいため、例えば、添加対象の石炭に粘結材を添加したうえで、上記温度に加熱して混練するようにしてもよく、或いは、予め添加対象の石炭を上記温度に加熱しておき、それに粘結材を添加して混練するようにしてもよい。なお、粘結材の軟化点については、後述の実施例を含めて、JIS K2425に規定されている方法により測定することができる。   In the present invention, the low-carbonized coal to which the caking additive is added is modified by heating and kneading at a temperature not lower than the softening point of the caking additive and not higher than 350 ° C. with the caking additive added. A caking additive is allowed to adhere to the coal to be reacted. In order to attach the binder to the coal, it is necessary to heat it above the softening point of the binder, but if heated to a temperature higher than 350 ° C., the deterioration (pyrolysis reaction) of the coal may proceed. is there. The kneading means is not particularly limited, and a known method such as a biaxial kneader or a pan-type kneader can be employed. In addition, since it is only necessary to be heated and kneaded in a state in which the binder is added, for example, after adding the binder to the coal to be added, the mixture may be heated and kneaded to the above temperature, Alternatively, the coal to be added may be heated in advance to the above temperature, and a caking additive may be added thereto and kneaded. In addition, about the softening point of a caking additive, it can measure by the method prescribed | regulated to JISK2425 including the below-mentioned Example.

粘結材の添加対象の石炭と粘結材とを加熱して混練したあとは、配合炭を構成する残りの石炭と配合して、コークス炉に装入する。ここで、残りの石炭とは、粘結材を添加していない石炭であって、平均反射率が0.9%超の高石炭化度炭や、平均反射率が0.65%未満の石炭(本願では便宜上「極低石炭化度炭」と記載する場合がある。)のほか、平均反射率が0.65%以上0.9%以下の範囲の石炭であっても粘結材を添加しなかったものも含まれ〔図1(2)の例で言えば石炭a〕、これらは、配合炭を構成する残りの石炭として、粘結材の添加対象の石炭と粘結材とを加熱して混練したあとに配合する。 After heating and kneading the coal to which the binder is to be added and the binder, the coal is mixed with the remaining coal constituting the coal blend and charged into the coke oven. Here, the remaining coal is coal to which no caking additive is added, and coal with a high degree of coalification with an average reflectance of more than 0.9% or coal with an average reflectance of less than 0.65%. (In this application, for the sake of convenience, it may be described as “very low-coalized coal”.) In addition, a binder is added even if the average reflectance is 0.65% or more and 0.9% or less. What was not done is also included [coal a 3 in the example of FIG. 1 (2)], these are the remaining coal constituting the blended coal, the coal to be added to the binder and the binder. Blend after heating and kneading.

粘結材が添加された状態で加熱・混練した低石炭化度炭については、配合炭を構成する残りの石炭と配合するにあたって、粘結材が添加されていない石炭との粒径を揃えるために、好ましくは篩下で10mm以下の大きさ、より好ましくは6mm以下に解砕するのがよい。粘結材と石炭を混練すると、石炭粒子が固まって塊状になることがある。その場合、配合炭を構成する残りの石炭と配合した際に、低石炭化度炭が集中する部分が生じて、得られるコークスが均質にならなくなるおそれがあることから、残りの石炭と配合する際に、予め解砕しておくのが望ましい。   For low-coalized coal that has been heated and kneaded with the binder added, when blending with the remaining coal that makes up the blended coal, to match the particle size of the coal without the binder Furthermore, it is preferable to crush to a size of 10 mm or less, more preferably 6 mm or less under a sieve. When the binder and coal are kneaded, the coal particles may solidify and become a lump. In that case, when blended with the remaining coal that constitutes the blended coal, there is a possibility that the low-coalized coal will concentrate and the resulting coke may not be homogeneous, so blend with the remaining coal At that time, it is desirable to disintegrate in advance.

上述したように、本発明によれば、所定の低石炭化度炭に対して粘結材を選択的に添加して、加熱し混練したうえで、配合炭を構成する残りの石炭と配合することで、コークス強度を維持しながら、粒径の大きなコークスを効果的に得ることができる。そのため、配合炭を構成する各石炭の事前の粉砕処理やコークス炉での乾留する際の条件等は、公知の方法と同様にすることができる。   As described above, according to the present invention, a caking additive is selectively added to a predetermined low coal content coal, heated and kneaded, and then blended with the remaining coal constituting the blended coal. Thus, coke having a large particle size can be effectively obtained while maintaining the coke strength. Therefore, the prior pulverization treatment of each coal constituting the blended coal, the conditions for dry distillation in a coke oven, and the like can be the same as those of known methods.

以下、実施例に基づき本発明をより詳細に説明するが、本発明は以下の内容に制限されるものではない。   EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not restrict | limited to the following content.

[コークス製造試験1(試験No.1-1〜1-5)]
平均反射率が0.76%の低石炭化度炭A(揮発分35.6%、最高流動度110ddpm)と、平均反射率が1.23%の高石炭化度炭B(揮発分24.5%、最高流動度540ddpm)とを用いて配合炭とし、次のようにして試験No.1−1〜1−5の試験用コークスを製造するコークス製造試験1を行った。
[Coke production test 1 (Test Nos. 1-1 to 1-5)]
Low-coalized coal A with an average reflectance of 0.76% (volatile content 35.6%, maximum fluidity 110ddpm) and high-coalized coal B with an average reflectance of 1.23% (volatile content 24.5%, maximum) Coke production test 1 was conducted to produce test cokes of Test Nos. 1-1 to 1-5 as follows.

先ず、低石炭化度炭Aをハンマー粉砕機で3mm以下が80%になるように粉砕し、コールタールから製造された硬ピッチC(軟化点85℃、揮発分54.2%)を同じくハンマー粉砕機により3mm以下となるように粉砕して、表1に示した配合炭(A+B)での低石炭化度炭Aの質量に応じて、低石炭化度炭Aに対して硬ピッチCが外数で10質量%となるように添加した(すなわちC/Aが10質量%)。次いで、これら低石炭化度炭Aと硬ピッチCとを150℃に加熱しながら、二軸混練機を用いて2分間の混練を行った。得られた混練物については、塊状になったものが認められたため、ハンマー粉砕機を用いて6mm以下になるように解砕した。   First, low-coalized coal A is pulverized with a hammer pulverizer so that 3 mm or less is 80%, and a hard pitch C (softening point 85 ° C., volatile content 54.2%) manufactured from coal tar is also used as a hammer pulverizer. According to the mass of the low coal degree coal A in the blended coal (A + B) shown in Table 1, the hard pitch C is an external number with respect to the low coal degree coal A. So as to be 10% by mass (that is, C / A is 10% by mass). Next, kneading was performed for 2 minutes using a twin-screw kneader while heating the low-coalizing coal A and the hard pitch C to 150 ° C. Since the obtained kneaded material was found to be in a lump shape, it was pulverized to 6 mm or less using a hammer pulverizer.

次いで、高石炭化度炭Bをハンマー粉砕機で3mm以下が80%になるように粉砕し、表1に示した配合炭の配合割合になるようにしながら、上記で低石炭化度炭Aと硬ピッチCとを加熱・混練した混練物と配合し、硬ピッチCと配合炭(A+B)との合計82kgを嵩密度800kg/mで試験コークス炉に装入した。そして、加熱温度を1250℃、乾留時間を18.5時間とする条件で乾留し、試験No.1−1〜1−5に係る試験用コークスをそれぞれ製造した。 Next, the high-coalized coal B is pulverized with a hammer pulverizer so that 3 mm or less is 80%, and the blending ratio of the coal blends shown in Table 1 is adjusted. Hard pitch C was blended with a kneaded product obtained by heating and kneading, and a total of 82 kg of hard pitch C and blended coal (A + B) was charged into a test coke oven at a bulk density of 800 kg / m 3 . And it co-distilled on the conditions which make heating temperature 1250 degreeC and a carbonization time 18.5 hours, and manufactured the test coke which concerns on test No.1-1-1-5, respectively.

得られた各試験用コークスについて、JIS K 2151のコークス粒度試験方法に基づきコークス平均粒度を測定した。また、コークス強度として、JIS K 2151のドラム強度指数(DI150 15)を測定した。結果を表1に示す。 About each obtained coke for a test, the coke average particle size was measured based on the coke particle size test method of JISK2151. Further, as a coke strength, a drum strength index (DI 150 15 ) of JIS K 2151 was measured. The results are shown in Table 1.

[コークス製造試験2(試験No.2-1〜2-5)]
低石炭化度炭Aと高石炭化度炭Bとをそれぞれハンマー粉砕機で3mm以下が80%になるように粉砕し、これらを表1に示した試験No.2−1〜2−5の割合になるように配合した。また、硬ピッチCをハンマー粉砕機で3mm以下になるように粉砕して、低石炭化度炭Aと高石炭化度炭Bとの配合炭(A+B)の質量に対して硬ピッチCが外数で10質量%となるように添加して(すなわちC/(A+B)が10質量%)、これらを150℃に加熱しながら、二軸混練機を用いて2分間の混練を行った。
[Coke production test 2 (Test Nos. 2-1 to 2-5)]
The low-carbonized coal A and the high-carbonized coal B were each pulverized with a hammer pulverizer so that 3 mm or less would be 80%, and these were tested Nos. 2-1 to 2-5 shown in Table 1 It mix | blended so that it might become a ratio. In addition, the hard pitch C is pulverized to 3 mm or less with a hammer pulverizer, and the hard pitch C is outside the mass of the coal blend (A + B) of the low coal degree coal A and the high coal degree coal B. Were added so as to be 10% by mass (that is, C / (A + B) was 10% by mass), and these were kneaded for 2 minutes using a twin-screw kneader while heating to 150 ° C. .

次いで、得られた混練物をハンマー粉砕機で6mm以下になるように解砕し、硬ピッチCと配合炭(A+B)との合計82kgを嵩密度800kg/mで試験コークス炉に装入して、コークス製造試験1と同様にして試験No.2−1〜2−5に係る試験用コークスを製造した。得られた試験用コークスについて、それぞれコークス製造試験1と同様にコークス平均粒度及びドラム強度指数(DI150 15)を測定した。結果を表1に示す。 Next, the obtained kneaded material was pulverized to 6 mm or less with a hammer pulverizer, and a total of 82 kg of hard pitch C and blended coal (A + B) was charged into a test coke oven at a bulk density of 800 kg / m 3. In the same manner as in the coke production test 1, test cokes according to Test Nos. 2-1 to 2-5 were produced. About the obtained test coke, the coke average particle diameter and the drum strength index (DI 150 15 ) were measured in the same manner as in the coke production test 1, respectively. The results are shown in Table 1.

[コークス製造試験3(試験No.3-1〜3-5)]
コークス製造試験2と同様に低石炭化度炭Aと高石炭化度炭Bとを配合して配合炭とし、配合炭(A+B)に対して硬ピッチCを添加するが、このコークス製造試験3では、粘結材の添加量をコークス製造試験1の場合と同じになるようにした。すなわち、配合炭(A+B)に対して硬ピッチCを添加する際、配合炭中の低石炭化度炭Aの質量に対して外数で10質量%となるように硬ピッチCを添加した(C/Aが10質量%)。それ以外はコークス製造試験2と同様にして混練物を得てハンマー粉砕機で解砕し、硬ピッチCと配合炭(A+B)との合計82kgを嵩密度800kg/mで試験コークス炉に装入して、試験No.3−1〜3−5に係る試験用コークスを製造した。得られた各試験用コークスについて、コークス製造試験1と同様にしてコークス平均粒度及びドラム強度指数(DI150 15)を測定した。結果を表1に示す。
[Coke production test 3 (test No.3-1 to 3-5)]
In the same manner as in the coke production test 2, the low coal degree coal A and the high coal degree coal B are blended to form a blended coal, and the hard pitch C is added to the blended coal (A + B). Then, the addition amount of the caking additive was made to be the same as in the case of the coke production test 1. That is, when adding the hard pitch C to the blended coal (A + B), the hard pitch C was added so as to be 10% by mass with respect to the mass of the low coal degree coal A in the blended coal ( C / A is 10% by mass). Otherwise, a kneaded product was obtained in the same manner as in Coke Production Test 2, and crushed with a hammer pulverizer, and a total of 82 kg of hard pitch C and blended coal (A + B) was loaded in a test coke oven at a bulk density of 800 kg / m 3. The test coke according to Test Nos. 3-1 to 3-5 was manufactured. The obtained each test coke, in the same manner as coke production test 1 to measure the coke average particle size and the drum strength index (DI 150 15). The results are shown in Table 1.

[コークス製造試験4(試験No.4-1〜4-5)]
コークス製造試験2と同様に低石炭化度炭Aと高石炭化度炭Bとを配合して配合炭(A+B)としたのち、硬ピッチCを添加せずに、配合炭82kgを嵩密度800kg/mで試験コークス炉に装入して、コークス製造試験1と同様にして試験No.4−1〜4−5に係る試験用コークスを製造した。得られた各試験用コークスについて、コークス製造試験1と同様にしてコークス平均粒度及びドラム強度指数(DI150 15)を測定した。結果を表1に示す。
[Coke production test 4 (Test Nos. 4-1 to 4-5)]
In the same manner as in Coke Production Test 2, low coal grade coal A and high coal grade coal B are blended to form blended coal (A + B), and then 82 kg of blended coal is added to 800 kg bulk density without adding hard pitch C. / M 3 was charged into a test coke oven, and test cokes according to Test Nos. 4-1 to 4-5 were manufactured in the same manner as in the coke manufacturing test 1. The obtained each test coke, in the same manner as coke production test 1 to measure the coke average particle size and the drum strength index (DI 150 15). The results are shown in Table 1.

Figure 2015174934
Figure 2015174934

上記コークス製造試験1〜4で得られた各試験用コークスについて、配合炭(A+B)における低石炭化度炭Aの配合率(%)とコークス平均粒度(mm)との関係をグラフにしたものが図3である。また、同じく低石炭化度炭Aの配合率(%)とドラム強度指数(−)との関係をグラフにしたものが図4である。これらのグラフから分かるように、低石炭化度炭Aに対して選択的に硬ピッチC(粘結材)を添加して加熱・混練したうえで、配合炭を構成する残りの高石炭化度炭Bと配合して、コークス炉に装入してコークスを製造するコークス製造試験1で得られたコークスは、配合炭(A+B)に対して硬ピッチCを添加し、加熱・混練してコークスを製造したコークス製造試験2及び3に比べて、コークス平均粒度及びドラム強度指数のいずれもが高い結果を示した。   For each test coke obtained in the above coke production tests 1 to 4, a graph showing the relationship between the blending ratio (%) of low-coalizing coal A in blended coal (A + B) and coke average particle size (mm) Is FIG. Similarly, FIG. 4 is a graph showing the relationship between the blending ratio (%) of low-rank coal A and the drum strength index (−). As can be seen from these graphs, after selectively adding hard pitch C (binding agent) to low-coalizing coal A and heating and kneading, the remaining high-coalizing degree constituting the blended coal The coke obtained in the coke production test 1 in which coke is produced by mixing with charcoal B and charged in a coke oven is added to the mixed charcoal (A + B) with a hard pitch C, heated and kneaded to produce coke. Compared with the coke production tests 2 and 3 in which the coke was produced, both the average particle size of the coke and the drum strength index showed high results.

すなわち、コークス製造試験1の場合よりも試験コークス炉に装入した装入炭として硬ピッチCの添加量が多いコークス製造試験2では、コークス製造試験3やコークス製造試験4の場合よりもコークス平均粒度が大きくなり、コークス製造試験1に近い結果を示すが(図3)、ドラム強度指数は逆に低下してしまうことが分かる(図4)。一方、ドラム強度指数については、装入炭として硬ピッチCの添加量がコークス製造試験1の場合と等しいコークス製造試験3の場合が、コークス製造試験1に次いで高い結果を示しているが(図4)、このコークス製造試験3でのコークス平均粒度は、添加材を含まないコークス製造試験4に比べて拡大してはいるものの、その効果は小さい。   That is, in the coke production test 2 in which the addition amount of the hard pitch C is larger as the charging coal charged into the test coke oven than in the case of the coke production test 1, the coke average is larger than in the coke production test 3 and the coke production test 4. Although the particle size becomes large and the result is close to the coke production test 1 (FIG. 3), it can be seen that the drum strength index is conversely lowered (FIG. 4). On the other hand, as for the drum strength index, the case of coke production test 3 in which the addition amount of hard pitch C as charging coal is equal to that in coke production test 1 shows the highest result after coke production test 1 (Fig. 4) Although the average particle size of the coke in the coke production test 3 is larger than that in the coke production test 4 that does not include an additive, the effect is small.

これに対して、本発明の高炉用コークスの製造方法に係るコークス製造試験1では、コークス平均粒度及びドラム強度指数ともに最も高い結果を示した。これは、低石炭化度炭に対して選択的に粘結材を添加して、加熱・混練して粘結材を付着させることで、その低石炭化度炭の再固化後の収縮率を低下させて、亀裂の発生を抑制したことにより、装入炭として硬ピッチCの添加量が多いコークス製造試験2の場合よりもコークス粒度を拡大させることができたものと考えられる。
また、コークス製造試験1では、粘結材を低石炭化度炭に選択的に添加することで、気孔率上昇に伴うコークス強度指数の低下を防ぐことができ(コークス製造試験2では硬ピッチCの添加量が多く、粘結材由来の揮発分が増してコークス強度は低下している)、装入炭として硬ピッチCの添加量が同じコークス製造試験3と同等以上のドラム強度指数を得ることができたものと考えられる。ここで、コークス製造試験3に比べて、コークス製造試験1でのドラム強度指数が若干高くなっているのは、粘結材を低石炭化度炭に選択的に添加することで、高石炭化度炭よりも脆弱な構造のコークスになり易い低石炭化度炭の粘結性が改善されて、より良好な構造のコークスになったことがひとつの理由として考えられる。
On the other hand, in the coke production test 1 according to the method for producing blast furnace coke of the present invention, the coke average particle size and the drum strength index showed the highest results. This is because the caking agent is selectively added to the low-coalizing coal, and the caking agent is adhered by heating and kneading to reduce the shrinkage rate after re-solidification of the low-coalizing coal. It is considered that the coke particle size was able to be expanded as compared with the case of the coke production test 2 in which the amount of hard pitch C added is large as the charging coal by suppressing the occurrence of cracks.
Further, in the coke production test 1, the caking strength index can be prevented from decreasing due to the increase in porosity by selectively adding the caking additive to the low-coalizing coal (in the coke production test 2, the hard pitch C The amount of volatile matter derived from the binder is increased and the coke strength is reduced), and a drum strength index equivalent to or higher than the coke production test 3 in which the addition amount of the hard pitch C is the same as the charging coal is obtained. It is thought that it was possible. Here, the drum strength index in the coke production test 1 is slightly higher than that in the coke production test 3 because the caking material is selectively added to the low-coalizing coal to increase the coal strength. One reason is that the coking property of low-coalized coal, which tends to become coke with a weaker structure than that of pre-coal, has been improved, resulting in a coke with a better structure.

[コークス製造試験1(試験No.1-6〜1-9)]
表2に示した配合炭(A+B)での低石炭化度炭Aの量に応じて、低石炭化度炭Aに対して硬ピッチCを外数で15質量%添加した場合(試験No.1-6)、低石炭化度炭Aに対して硬ピッチCを外数で5質量%添加した場合(試験No.1-7)、低石炭化度炭Aに対して硬ピッチCを外数で20質量%添加した場合(試験No.1-8)、及び、低石炭化度炭Aに対して硬ピッチCを外数で3質量%添加した場合(試験No.1-9)について、それ以外は上記試験No.1−1〜1−5のコークス製造試験1と同様にして試験用コークスを製造した。得られた試験用コークスのコークス平均粒度及びドラム強度指数(DI150 15)をコークス製造試験1と同様に測定した。結果を表2に示す。
[Coke production test 1 (Test Nos. 1-6 to 1-9)]
According to the amount of the low coal degree coal A in the blended coal (A + B) shown in Table 2, when 15 mass% of the hard pitch C is added to the low coal degree coal A in an external number (test No. 1-6) When 5% by mass of hard pitch C is added to low-carbonized coal A (test No. 1-7), hard pitch C is removed from low-carbonized coal A When 20% by mass is added (test No. 1-8) and when 3% by mass of hard pitch C is added to low-carbonized coal A (test No. 1-9) Otherwise, a test coke was produced in the same manner as in the above-mentioned test Nos. 1-1 to 1-5. The coke average particle size and drum strength index (DI 150 15 ) of the obtained test coke were measured in the same manner as in the coke production test 1. The results are shown in Table 2.

Figure 2015174934
Figure 2015174934

表2に示したように、低石炭化度炭Aに対して硬ピッチCを20質量%(外数)添加した試験No.1−8では、コークスの平均粒度は向上するものの、ドラム強度指数は最も低い値であった。また、低石炭化度炭Aに対して硬ピッチCを3質量%(外数)添加した試験No.1−9では、コークスの平均粒度が最も低い値であった。それに対して、試験No.1−6及び試験No.1−7で得られたコークスは、コークス平均粒度及びドラム強度指数ともに比較的高い値を示し、これらの両立が図られていた。   As shown in Table 2, in test No. 1-8 in which 20% by mass (external number) of hard pitch C was added to low-coalized coal A, the average particle size of coke was improved, but the drum strength index Was the lowest value. Moreover, in test No. 1-9 in which 3% by mass (outer number) of hard pitch C was added to low-carbonized coal A, the average particle size of coke was the lowest value. On the other hand, the cokes obtained in Test No. 1-6 and Test No. 1-7 showed relatively high values for both the average coke particle size and the drum strength index, and both of these were achieved.

[コークス製造試験5、6]
平均反射率が0.77%の低石炭化度炭D(揮発分34.8%、最高流動度92ddpm)、平均反射率が0.86%の低石炭化度炭E(揮発分35.1%、最高流動度8250ddpm)、及び、平均反射率が1.38%の高石炭化度炭F(揮発分21.3%、最高流動度180ddpm)を用いて配合炭とし、次のようにして試験用コークスを製造するコークス製造試験5、6を行った。
[Coke production test 5, 6]
Low-coalized coal D with an average reflectance of 0.77% (volatile content 34.8%, maximum fluidity 92ddpm), low-carbonized coal E with an average reflectance of 0.86% (volatile content 35.1%, maximum fluidity) 8250 ddpm) and high-coalized coal F with an average reflectance of 1.38% (volatile content 21.3%, maximum fluidity 180 ddpm) is used as a blended coal, and test coke is produced as follows. Coke production tests 5 and 6 were conducted.

先ず、低石炭化度炭Dをハンマー粉砕機で3mm以下が80%になるように粉砕して、表3に示した配合炭(D+E+F)での低石炭化度炭Dの質量に対して、軟ピッチG(軟化点36.8℃、揮発分72.0%)を外数で8質量%となるように添加した(G/Dが8質量%)。次いで、これら低石炭化度炭Dと軟ピッチGとを90℃に加熱しながら、二軸混練機を用いて3分間の混練を行った。得られた混練物については、塊状になったものが認められたため、ハンマー粉砕機を用いて6mm以下になるように解砕した。   First, low-carbonized coal D is pulverized with a hammer pulverizer so that 3 mm or less is 80%, and the mass of low-carbonized coal D in the blended coal (D + E + F) shown in Table 3 is as follows. Soft pitch G (softening point 36.8 ° C., volatile content 72.0%) was added so that the external number was 8% by mass (G / D was 8% by mass). Next, kneading was carried out for 3 minutes using a twin-screw kneader while heating the low-rank coal D and soft pitch G to 90 ° C. Since the obtained kneaded material was found to be in a lump shape, it was pulverized to 6 mm or less using a hammer pulverizer.

次いで、低石炭化度炭Eをハンマー粉砕機で3mm以下が80%になるように粉砕すると共に、高石炭化度炭Fをハンマー粉砕機で3mm以下が80%になるように粉砕し、表3に示した配合炭(D+E+F)の配合割合になるようにしながら、上記で低石炭化度炭Dと軟ピッチGとを加熱・混練した混練物と配合し、軟ピッチGと配合炭(D+E+F)との合計82kgを嵩密度800kg/mで試験コークス炉に装入した。そして、加熱温度を1250℃、乾留時間を18.5時間とする条件で乾留し、コークス製造試験5に係る試験用コークスを製造した。 Next, the low-coalized coal E is pulverized with a hammer pulverizer so that 3 mm or less is 80%, and the high-coalized coal F is pulverized with a hammer pulverizer so that 3 mm or less is 80%. 3 is blended with the kneaded material obtained by heating and kneading the low-coalizing coal D and the soft pitch G as described above while maintaining the blending ratio of the blended coal (D + E + F) shown in FIG. ) Was charged into the test coke oven at a bulk density of 800 kg / m 3 . And it co-distilled on the conditions which make heating temperature 1250 degreeC and carbonization time 18.5 hours, and manufactured the test coke which concerns on the coke manufacturing test 5.

一方で、低石炭化度炭D、低石炭化度炭E、及び高石炭化度炭Fをそれぞれハンマー粉砕機で3mm以下が80%になるように粉砕し、これらを表3に示した配合炭(D+E+F)の割合になるように配合した。そして、配合炭(D+E+F)の質量に対して軟ピッチGが外数で3.2質量%となるように添加して(G/(D+E+F)が8質量%)、これらを90℃に加熱しながら、二軸混練機を用いて3分間の混練を行った。次いで、得られた混練物をハンマー粉砕機で6mm以下になるように解砕し、軟ピッチGと配合炭(D+E+F)との合計82kgを嵩密度800kg/mで試験コークス炉に装入して、コークス製造試験5と同様の乾留条件にてコークス製造試験6に係る試験用コークスを製造した。
コークス製造試験5及び6で得られた各試験用コークスについて、コークス製造試験1と同様にしてコークス平均粒度及びドラム強度指数(DI150 15)を測定した。結果を表3に示す。
On the other hand, the low coalized coal D, the low coalified coal E, and the high coal coal F are pulverized with a hammer pulverizer so that 3 mm or less is 80%, and these are shown in Table 3. It mix | blended so that it might become a ratio of charcoal (D + E + F). And it added so that the soft pitch G might be 3.2 mass% in an external number with respect to the mass of a combination charcoal (D + E + F) (G / (D + E + F) is 8 mass%), and these are added. While heating at 0 ° C., kneading was performed for 3 minutes using a twin-screw kneader. Next, the obtained kneaded material was pulverized to 6 mm or less with a hammer pulverizer, and a total of 82 kg of soft pitch G and blended coal (D + E + F) was charged into a test coke oven at a bulk density of 800 kg / m 3. Thus, coke for test according to coke production test 6 was produced under the same dry distillation conditions as in coke production test 5.
For each test coke obtained in coke production tests 5 and 6, the coke average particle size and drum strength index (DI 150 15 ) were measured in the same manner as in coke production test 1. The results are shown in Table 3.

Figure 2015174934
Figure 2015174934

表3に示した結果から明らかなように、ドラム強度指数はコークス製造試験5とコークス製造試験6とで大きな差はなかったが、コークス平均粒度については、低石炭化度の一部に対して軟ピッチG(粘結材)を選択的に添加したコークス製造試験5の方が優れることが分かった。すなわち、本発明に係る高炉用コークスの製造方法によれば、コークス平均粒度とドラム強度指数がともに良好なコークスの製造が可能であり、粘結材の働きを従来に比べて効率良く得ることができる。   As is apparent from the results shown in Table 3, the drum strength index was not significantly different between the coke production test 5 and the coke production test 6, but the coke average particle size was a part of the low coalification degree. It was found that the coke production test 5 to which soft pitch G (binding agent) was selectively added was superior. That is, according to the method for producing coke for blast furnace according to the present invention, coke having good coke average particle size and drum strength index can be produced, and the function of the binder can be obtained more efficiently than before. it can.

Claims (6)

少なくとも平均反射率が0.65%以上0.9%以下の低石炭化度炭と平均反射率が0.9%超の高石炭化度炭とを配合した配合炭をコークス炉に装入して、高炉用コークスを製造する方法において、平均反射率が前記の低石炭化度炭の範囲に含まれる銘柄の石炭に対する割合で5質量%以上15質量%以下の粘結材が添加された状態で、該銘柄の石炭と粘結材とを粘結材の軟化点以上350℃以下の範囲に加熱して混練したうえで、配合炭を構成する残りの石炭と配合して、コークス炉に装入することを特徴とする高炉用コークスの製造方法。   At least a coal blended with a low-coalized coal with an average reflectance of 0.65% or more and 0.9% or less and a high-carbonized coal with an average reflectance of more than 0.9% is charged into a coke oven. In the method for producing coke for blast furnace, a state in which a binder of 5 mass% or more and 15 mass% or less is added in terms of the ratio of the average reflectance to the coal of the brand included in the range of the low-coalizing coal. The coal and caking material of the brand are heated and kneaded in the range of the softening point of the caking additive to 350 ° C or less, and then blended with the remaining coal constituting the blended coal, and installed in the coke oven. A method for producing coke for a blast furnace, characterized by comprising: 平均反射率が前記の低石炭化度炭の範囲に含まれる石炭が複数銘柄存在し、そのうちの少なくとも1つ又は2つ以上の銘柄の石炭について、1銘柄の石炭に対する割合で5質量%以上15質量%以下の粘結材が添加された状態で加熱し混練して、配合炭を構成する残りの石炭と配合する請求項1に記載の高炉用コークスの製造方法。   There are a plurality of coals whose average reflectance is included in the range of the low-coalizing coal, and at least one or two or more of these coals are 5% by mass or more in proportion to one brand of coal. The manufacturing method of the coke for blast furnaces of Claim 1 which heats and knead | mixes in the state in which the binder of the mass% or less was added, and mix | blends with the remaining coal which comprises a blended coal. 粘結材を添加する前記の低石炭化度炭が、JIS M8801による最高流動度が10ddpm以上である請求項1又は2に記載の高炉用コークスの製造方法。   The method for producing coke for blast furnace according to claim 1 or 2, wherein the low-coalizing coal to which the binder is added has a maximum fluidity of 10 ddpm or more according to JIS M8801. 粘結材の揮発分が60質量%以下である請求項1〜3のいずれかに記載の高炉用コークスの製造方法。   The volatile matter of a caking additive is 60 mass% or less, The manufacturing method of the coke for blast furnaces in any one of Claims 1-3. 粘結材が石炭系粘結材である請求項1〜4のいずれかに記載の高炉用コークスの製造方法。   The method for producing coke for blast furnace according to any one of claims 1 to 4, wherein the binder is a coal-based binder. 粘結材が添加された状態で加熱し混練した低石炭化度炭を10mm以下の大きさに解砕した後、配合炭を構成する残りの石炭と配合する請求項1〜5のいずれかに記載の高炉用コークスの製造方法。   The low-coalized coal heated and kneaded in a state where the binder is added is crushed to a size of 10 mm or less, and then blended with the remaining coal constituting the blended coal. A method for producing the blast furnace coke as described.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018162427A (en) * 2017-03-27 2018-10-18 三菱ケミカル株式会社 Producing method of coke
JP2019002011A (en) * 2017-06-19 2019-01-10 新日鐵住金株式会社 Method for manufacturing coke
CN112831805A (en) * 2021-01-06 2021-05-25 山西沁新能源集团股份有限公司 Method for preparing prebaked anode by using bituminous coal, prebaked anode prepared by method and application of prebaked anode

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Publication number Priority date Publication date Assignee Title
JPS5212721B2 (en) * 1971-10-22 1977-04-09
JPS56135593A (en) * 1980-03-28 1981-10-23 Kansai Coke & Chem Co Ltd Production of coke
JPS5861177A (en) * 1981-10-09 1983-04-12 Kansai Coke & Chem Co Ltd Selection of pitch for softening and melting of coal

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5212721B2 (en) * 1971-10-22 1977-04-09
JPS56135593A (en) * 1980-03-28 1981-10-23 Kansai Coke & Chem Co Ltd Production of coke
JPS5861177A (en) * 1981-10-09 1983-04-12 Kansai Coke & Chem Co Ltd Selection of pitch for softening and melting of coal

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018162427A (en) * 2017-03-27 2018-10-18 三菱ケミカル株式会社 Producing method of coke
JP2019002011A (en) * 2017-06-19 2019-01-10 新日鐵住金株式会社 Method for manufacturing coke
CN112831805A (en) * 2021-01-06 2021-05-25 山西沁新能源集团股份有限公司 Method for preparing prebaked anode by using bituminous coal, prebaked anode prepared by method and application of prebaked anode

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