JP6737259B2 - Coke production method - Google Patents
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本発明は、コークスの製造に関するものであり、石炭の粘結性を向上させて高強度なコークスを製造できるコークスの製造方法に関するものである。 TECHNICAL FIELD The present invention relates to coke production, and relates to a coke production method capable of producing high-strength coke by improving the caking property of coal.
高炉で銑鉄を製造するには、高炉に鉄鉱石類とコークスを交互に装入することでそれぞれを層状に充填し、羽口から吹き込まれる高温の熱風で鉄鉱石類やコークスを加熱すると共に、主にコークスから発生したＣＯガスで鉄鉱石類を還元し溶製することが必要である。こうした高炉の操業を安定して行なうには、炉内での通気性や通液性を向上させることが有効であり、このためには強度、粒度および反応後強度等の諸特性に優れたコークスの使用が不可欠である。 To produce pig iron in a blast furnace, iron ores and coke are alternately charged into the blast furnace to fill each in layers, and the iron ore and coke are heated by the hot air blown from the tuyere, It is necessary to reduce iron ores mainly with CO gas generated from coke and to produce them. For stable operation of such a blast furnace, it is effective to improve air permeability and liquid permeability in the furnace. For this purpose, coke having excellent characteristics such as strength, particle size and strength after reaction. The use of is essential.
高炉等の竪型炉内の通気性や通液性を向上させるには、高強度のコークスを使用することが有効である。コークスは、通常、ＪＩＳ Ｋ ２１５１に規定されている回転強度試験により測定されるドラム強度ＤＩ（１５０／１５）などを指標として強度管理が行われている。 The use of high-strength coke is effective for improving air permeability and liquid permeability in a vertical furnace such as a blast furnace. Coke is generally subjected to strength management by using, for example, a drum strength DI (150/15) measured by a rotation strength test defined in JIS K 2151 as an index.
高強度なコークスを製造するには、主たる原料として強粘結炭を用いる必要がある。しかし、近年、世界的な鉄鋼需要の増加に伴い、強粘結炭の需要増大を招き、将来的にはその枯渇を想定しなければならなくなっている。このため、今後のコークス製造においては、微粘結炭や非粘結炭などの、より低品位の石炭を多量に使用することが重要となる。しかしながら、低品位の石炭は粘結性が低いので、低品位の石炭を使用するとコークス化する際に石炭粒子の接着が不十分となりコークス強度が低下する。したがって、低品位の石炭の粘結性を向上させる石炭改質の技術開発が進められている。 In order to produce high-strength coke, it is necessary to use strong coking coal as a main raw material. However, in recent years, the demand for strong coking coal has increased as the global demand for steel has increased, and it has become necessary to anticipate its exhaustion in the future. Therefore, in the future coke production, it is important to use a large amount of lower-grade coal such as slightly caking coal and non-caking coal. However, since low-grade coal has low caking properties, when low-grade coal is used, the adhesion of coal particles becomes insufficient when coking and the coke strength decreases. Therefore, technological development of coal reforming for improving the caking property of low-grade coal is underway.
石炭改質の技術として、例えば、特許文献１には、低品位炭を粘結炭より細かく粉砕して乾燥させ、タール、重質油、ピッチ類などのバインダーを混練することで低品位炭を改質する原料炭の事前処理方法が開示されている。特許文献２には、低品位炭を重質油類とともに加熱し、低品位炭表面に重質油類の分解生成物を付着させることで、処理過程で水を多量に発生させずに低品位炭を人造粘結炭に改質する方法が開示されている。また、特許文献３には、改質剤としてＮ、Ｎ’−ジ−２−ナフチル−ｐ−フェニレンジアミンを配合炭に添加する石炭の改質方法が開示されている。 As a technique of coal reforming, for example, in Patent Document 1, low-grade coal is finely crushed from caking coal and dried, and low-grade coal is obtained by kneading a binder such as tar, heavy oil, and pitches. A method of pre-treating a coking coal to be reformed is disclosed. In Patent Document 2, low-grade coal is heated together with heavy oils, and the decomposition products of the heavy oils are attached to the surface of the low-grade coals so that a large amount of water is not generated in the treatment process and low-grade coals are produced. A method for modifying charcoal into artificial coking coal is disclosed. Further, Patent Document 3 discloses a method for reforming coal in which N,N'-di-2-naphthyl-p-phenylenediamine is added to blended coal as a modifier.
石炭を改質するには、改質剤となる物質を石炭に添加する必要がある。例えば、特許文献１では、タール、重質油およびピッチ類、特許文献２では重質油類、特許文献３ではＮ，Ｎ’−ジ−２−ナフチル−ｐ−フェニレンジアミンが改質剤にあたる。このような改質剤を入手するにはコストがかかり、したがって、改質剤の価格と、粘結炭と低品位炭の価格差次第では、改質剤の添加によりかえって配合炭のコストが高くなる。また、特許文献１、２については、複雑な改質処理工程を経る必要があるので、改質処理設備の建設費やランニングコストなども考慮する必要がある。本発明は、このような従来技術を鑑みてなされたものであり、その目的とするところは、改質剤を添加することなく単純なプロセスで石炭を改質し、改質された石炭を用いて高強度なコークスを製造するコークスの製造方法を提供することにある。 In order to modify coal, it is necessary to add a substance that serves as a modifier to the coal. For example, in Patent Document 1, tar, heavy oil, and pitches, in Patent Document 2, heavy oils, and in Patent Document 3, N,N'-di-2-naphthyl-p-phenylenediamine is a modifier. It is expensive to obtain such a modifier, and therefore, depending on the price of the modifier and the price difference between the coking coal and the low-grade coal, the cost of the blended coal is rather high due to the addition of the modifier. Become. Further, in Patent Documents 1 and 2, since it is necessary to go through a complicated reforming treatment step, it is necessary to consider the construction cost and running cost of the reforming treatment facility. The present invention has been made in view of such a conventional technique, and an object thereof is to reform coal by a simple process without adding a modifier, and use the reformed coal. Another object of the present invention is to provide a coke manufacturing method for manufacturing coke having high strength.
［１］水に浸漬させた浸漬水のｐＨが７．０未満となる酸滲出石炭と他の石炭とを水中に保持する保持ステップと、前記保持ステップで水に保持された他の石炭を、コークスを製造する際に用いる配合炭の一部または全部に配合する配合ステップと、前記配合ステップで配合された前記配合炭をコークス炉で乾留するコークス製造ステップと、を含む、コークスの製造方法。
［２］前記酸滲出石炭は、浸漬水における前記酸滲出石炭１ｇあたりの水素イオンのモル数が８．０×１０−７ｍоｌ／ｇ以上である、［１］に記載のコークスの製造方法。
［３］前記酸滲出石炭は、浸漬水における前記酸滲出石炭１ｇあたりの硫酸イオン量が０．４ｍｇ／ｇ以上である、［１］または［２］に記載のコークスの製造方法。
［４］前記保持ステップにおける水に保持する前記酸滲出石炭の質量と前記他の石炭との質量は、下記（１）式を満足する、［１］から［３］の何れか１つに記載のコークスの製造方法。
酸滲出石炭の質量／他の石炭の質量≧１・・・（１）
［５］前記保持ステップにおける前記酸滲出石炭と前記他の石炭とを水に保持する時間は、１時間以上１４日以下である、［１］から［４］の何れか１つに記載のコークスの製造方法。
［６］前記保持ステップにおける前記酸滲出石炭と前記他の石炭とを保持する水の温度は、０℃以上６０℃以下である、［１］から［５］の何れか１つに記載のコークスの製造方法。
[1] A holding step of holding the acid-leached coal having pH of less than 7.0 and another coal soaked in water in water, and another coal held in water in the holding step, A method for producing coke, comprising: a blending step of blending a part or all of the blended coal used when producing coke, and a coke producing step of carbonizing the blended coal blended in the blending step in a coke oven.
[2] The method for producing coke according to [1], wherein the acid-leached coal has a molar number of hydrogen ions per 1 g of the acid-leached coal in immersion water of 8.0×10 −7 mol/g or more.
[3] The method for producing coke according to [1] or [2], wherein the acid-leached coal has a sulfate ion amount of 0.4 mg/g or more per 1 g of the acid-leached coal in immersion water.
[4] The mass of the acid-leached coal retained in water and the mass of the other coal in the retaining step satisfy the following equation (1), and are described in any one of [1] to [3]. Manufacturing method of coke.
Mass of acid-leached coal/mass of other coal ≧1...(1)
[5] The coke according to any one of [1] to [4], wherein a time for holding the acid-leached coal and the other coal in water in the holding step is 1 hour or more and 14 days or less. Manufacturing method.
[6] The coke according to any one of [1] to [5], wherein the temperature of the water holding the acid-leached coal and the other coal in the holding step is 0° C. or higher and 60° C. or lower. Manufacturing method.
本発明の実施により、改質剤を添加することなく水に石炭を浸漬させるという単純なプロセスで石炭を改質でき、当該改質された石炭を用いて高強度なコークスを製造できる。 By carrying out the present invention, coal can be modified by a simple process of immersing coal in water without adding a modifier, and high-strength coke can be produced using the modified coal.
まず、本発明をするに至った経緯について説明する。本発明者らは、改質剤を用いることなく石炭の粘結性を向上させることを目的として石炭の粘結性への影響因子を調査した。非特許文献１には、石炭に含まれる無機物質である鉱物質が軟化溶融性に影響を及ぼすことが記載されている。非特許文献２には、石炭に無機物質であるカルシウム塩や鉄の塩などを添加すると、石炭の軟化溶融性が低下することが記載されている。これら文献の記載から、本発明者らは、石炭中の鉱物質を除去することで石炭の粘結性を改善できると考えた。 First, the background of the invention will be described. The present inventors investigated the influencing factors on the caking property of coal for the purpose of improving the caking property of coal without using a modifier. Non-Patent Document 1 describes that an inorganic substance, which is an inorganic substance contained in coal, affects the softening and melting property. Non-Patent Document 2 describes that the softening and melting property of coal decreases when an inorganic substance such as calcium salt or iron salt is added to coal. From the description of these documents, the present inventors considered that the caking property of coal could be improved by removing the mineral substances in the coal.
灰分の除去については、コークス製造分野だけでなく、さまざまな分野で灰分除去技術が報告されている。例えば、特許文献４には、石炭の化学的脱灰処理として、酸やアルカリによる処理や、フッ酸やフッ化水素ガスによる処理が記載されている。ただし、特許文献４には、酸もしくはアルカリによる脱灰処理は、加圧下および加熱条件下で行わないと効果が小さいことも記載されている。 Regarding ash removal, ash removal technology has been reported not only in the coke manufacturing field but also in various fields. For example, in Patent Document 4, as a chemical deashing treatment of coal, a treatment with an acid or an alkali or a treatment with hydrofluoric acid or hydrogen fluoride gas is described. However, Patent Document 4 also describes that the effect of deashing with an acid or an alkali is small unless it is performed under pressure and under heating conditions.
一方、非特許文献３には、常圧、常温条件下で石炭に酸処理を施すことで、石炭の灰分中のカルシウム、マグネシウムといったアルカリ土類金属や鉄を取り除くことができ、これによりコークス化した際の組織の発達が促進されることが記載されている。この文献の記載から、本発明者らは、石炭に酸処理を施すことで、石炭に含まれる鉱物質のうち、カルシウム、マグネシウム、鉄などの成分を取り除くことができれば、石炭の粘結性を向上できる可能性があると考えた。しかしながら、酸処理するには塩酸などの酸が必要であり、酸溶液を用いることは改質剤を添加する場合と同じく製造コストの上昇を招く。 On the other hand, in Non-Patent Document 3, alkaline earth metals such as calcium and magnesium and iron in coal ash can be removed by subjecting coal to acid treatment under normal pressure and room temperature conditions, thereby coking. It is described that tissue development is promoted when the treatment is performed. From the description of this document, the present inventors, by subjecting the coal to an acid treatment, of the mineral substances contained in the coal, if the components such as calcium, magnesium, and iron can be removed, the caking property of the coal will be improved. I thought it could be improved. However, acid treatment requires an acid such as hydrochloric acid, and the use of an acid solution causes an increase in manufacturing cost as in the case of adding a modifier.
製造コストの上昇を回避するために、本発明者らは石炭由来の酸を用いることを考えた。図１は、石炭を浸漬させた浸漬水のｐＨの経時変化を示すグラフである。図１でｐＨの経時変化を確認した浸漬水は、Ａ〜Ｎ銘柄の石炭５０ｇを４００ｍｌの純水に完全に浸漬させ６０℃まで加熱した浸漬水である。また、２時間経過後のＡ〜Ｎ銘柄の石炭を浸漬させた浸漬水のｐＨを下記表１に示す。 In order to avoid an increase in manufacturing costs, the inventors considered using coal-derived acid. FIG. 1 is a graph showing a change with time in pH of immersion water in which coal is immersed. The immersion water whose pH has been confirmed to change with time in FIG. 1 is immersion water obtained by completely immersing 50 g of A to N brand coal in 400 ml of pure water and heating it to 60°C. Further, the pH of the immersion water in which the coals of A to N brands are immersed after 2 hours is shown in Table 1 below.
図１および表１に示すように、石炭の銘柄によっては石炭を浸漬させた浸漬水のｐＨが７．０未満、すなわち、浸漬水が酸性になることが確認された。浸漬水が酸性になる理由は、石炭中に含まれる、水に溶解して酸性を示す鉱物が浸漬水に溶出することによると考えられる。 As shown in FIG. 1 and Table 1, it was confirmed that the pH of the immersion water in which the coal was immersed was less than 7.0, that is, the immersion water became acidic depending on the brand of coal. It is considered that the reason why the immersion water becomes acidic is that the minerals contained in the coal, which dissolve in water and exhibit acidity, are eluted into the immersion water.
図２は、石炭を２時間浸漬させた後の浸漬水のｐＨと、浸漬水の硫酸イオン濃度との関係を示すグラフである。図２において、縦軸は硫酸イオン濃度（ｍｇ／Ｌ）であり、横軸はｐＨである。また、縦軸に石炭１ｇあたりの浸漬水の硫酸イオン量（ｍｇ／ｇ）を併記し、横軸に石炭１ｇあたりの浸漬水の水素イオンのモル数（ｍоｌ／ｇ）を併記した。 FIG. 2 is a graph showing the relationship between the pH of immersion water after immersing coal for 2 hours and the sulfate ion concentration of the immersion water. In FIG. 2, the vertical axis represents sulfate ion concentration (mg/L), and the horizontal axis represents pH. The vertical axis also shows the amount of sulfate ions (mg/g) of immersion water per 1 g of coal, and the horizontal axis also shows the number of moles of hydrogen ions (mol/g) of immersion water per 1 g of coal.
図２に示すように、浸漬水のｐＨが７．０以上となる石炭では、浸漬水の硫酸イオン濃度が５０ｍｇ／Ｌより低くなり、浸漬水のｐＨが７．０未満の酸滲出石炭では、浸漬水の硫酸イオン濃度が５０ｍｇ／Ｌ以上になった。このことから、石炭から浸漬水に溶出した硫酸塩鉱物が石炭を浸漬させた浸漬水のｐＨを７．０未満にする、すなわち、石炭を浸漬させた浸漬水が酸性になることに関係していることがわかる。 As shown in FIG. 2, in the coal in which the pH of the immersion water is 7.0 or more, the sulfate ion concentration of the immersion water is lower than 50 mg/L, and in the acid-leached coal in which the pH of the immersion water is less than 7.0, The sulfate ion concentration of the immersion water became 50 mg/L or more. From this, it is related to that the sulfate mineral eluted from the coal into the immersion water makes the pH of the immersion water in which the coal is immersed less than 7.0, that is, the immersion water in which the coal is immersed becomes acidic. You can see that
このように、石炭の銘柄によっては、石炭を浸漬させた浸漬水が酸性になる酸滲出石炭が存在する。そして、当該酸滲出石炭を用いることで、改質剤や酸溶液を新たに用いることなく石炭由来の酸を用いて低品位炭を改質できる。また、石炭由来の酸を用いることで、酸滲出石炭と低品位炭とを水中に保持するという単純なプロセスで低品位炭を改質でき、当該改質された低品位炭を用いることで高強度なコークスが製造できることを見出して本発明を完成させた。以下、本発明を発明の実施形態を通じて説明する。 Thus, depending on the brand of coal, there is acid-leached coal in which the immersion water in which the coal is immersed becomes acidic. Then, by using the acid-leached coal, it is possible to reform low-grade coal by using coal-derived acid without newly using a modifier or an acid solution. Moreover, by using the acid derived from coal, the low-grade coal can be reformed by a simple process of keeping the acid-leached coal and the low-grade coal in water, and by using the modified low-grade coal, The present invention has been completed by finding that strong coke can be produced. Hereinafter, the present invention will be described through embodiments of the invention.
本実施形態に係るコークスの製造方法は、水に浸漬させた浸漬水のｐＨが７．０未満となる酸滲出石炭と低品位炭とを所定量の水の中に保持する保持ステップと、コークスを製造する際に用いる配合炭の一部または全部に、保持ステップで保持された低品位炭を配合する配合ステップと、配合ステップで配合された配合炭をコークス炉で乾留してコークスを製造するコークス製造ステップとを含む。なお、本実施形態において、低品位炭とは、粘結性の低い石炭であって、酸滲出石炭とは異なる他の石炭である。 The method for producing coke according to the present embodiment, a holding step of holding in a predetermined amount of water the acid-leached coal and the low-grade coal in which the pH of the immersion water immersed in water is less than 7.0, and coke. To produce coke by partially distilling the coal blend blended in the blending step and the blend coal blended in the blending step in a coke oven to a part or all of the coal blend used in manufacturing A coke making step. In the present embodiment, the low-grade coal is a coal having low caking property and is another coal different from the acid-leached coal.
本実施形態における保持ステップでは、酸滲出石炭と低品位炭とを所定量の水に入れ、水中に数時間から数日間保持する。ここで、所定量の水とは、酸滲出石炭と低品位炭と完全に浸漬する水量であることが好ましいが、必ずしも完全に浸漬しなくてもよく、酸滲出石炭と低品位炭の一部が浸漬する水量であればよい。酸滲出石炭の少なくとも一部が浸漬していれば、酸滲出石炭から滲出する酸により浸漬水のｐＨが低下し、浸漬水に浸漬されている低品位炭からカルシウム、マグネシウムおよび鉄などが浸漬水中に溶出する。これにより、低品位炭からカルシウム、マグネシウムおよび鉄などの成分が取り除かれ、低品位炭の少なくとも一部が改質されて、当該部分の粘結性が向上する。 In the holding step in this embodiment, the acid-leached coal and the low-grade coal are put in a predetermined amount of water and held in the water for several hours to several days. Here, the predetermined amount of water is preferably the amount of water that is completely immersed in the acid-leached coal and the low-grade coal, but does not necessarily have to be completely immersed, and part of the acid-leached coal and the low-grade coal. Any amount of water can be used. If at least a part of the acid-leached coal is immersed, the pH of the steep water is lowered by the acid that is exuded from the acid-leached coal, and calcium, magnesium, iron, etc. from the low-grade coal that is soaked in the steep water Elute into. As a result, components such as calcium, magnesium and iron are removed from the low-grade coal, at least a part of the low-grade coal is modified, and the caking property of the part is improved.
保持ステップにおける酸滲出石炭と低品位炭とを保持する水の温度は、０℃以上６０℃以下の範囲内であることが好ましい。水の温度が６０℃を超えると、石炭の風化が助長されるので好ましくない。また、０℃以下になると水が凝固し、低品炭からカルシウム、マグネシウムおよび鉄などの成分が取り除かれにくくなるので好ましくない。 The temperature of the water holding the acid-leached coal and the low-grade coal in the holding step is preferably in the range of 0°C or higher and 60°C or lower. When the temperature of water exceeds 60°C, weathering of coal is promoted, which is not preferable. Further, if the temperature is 0° C. or lower, water is solidified and it becomes difficult to remove components such as calcium, magnesium and iron from low-grade coal, which is not preferable.
保持ステップにおける水に酸滲出石炭と低品位炭を保持する時間は、１時間以上１４日以下の範囲内であることが好ましい。酸滲出石炭と低品位炭とを浸漬水に１時間保持すれば、低品位炭からカルシウム、マグネシウムおよび鉄が浸漬水中に溶出され、低品位炭を改質できる。一方、酸滲出石炭と低品位炭とを水に１４日以上保持すると、低品位炭が酸化され、低品位炭の粘結性が逆に低下するので好ましくない。酸滲出石炭と低品位炭とは、浸漬水で所定時間保持された後に、浸漬水から取り出されて脱水される。 The time for holding the acid-leached coal and the low-grade coal in water in the holding step is preferably in the range of 1 hour or more and 14 days or less. When the acid-leached coal and the low-grade coal are kept in the immersion water for 1 hour, calcium, magnesium and iron are eluted from the low-grade coal into the immersion water, and the low-grade coal can be reformed. On the other hand, if the acid-leached coal and the low-grade coal are kept in water for 14 days or more, the low-grade coal is oxidized and the caking property of the low-grade coal is lowered, which is not preferable. The acid-leached coal and the low-grade coal are held in the immersion water for a predetermined time, then taken out from the immersion water and dehydrated.
配合ステップでは、コークスを製造する際に用いられる配合炭の一部または全部に、保持ステップで改質された低品位炭が配合される。配合炭は、その後、コークスの製造に適するような粒度および水分に調整される。保持ステップで浸漬水中に保持された低品位炭は、カルシウム、マグネシウムおよび鉄などが除去されて粘結性が向上しているので、当該低品位炭を配合炭に用いてコークスを製造することで、粘結性が向上されていない低品位炭が配合された配合炭を用いて製造されたコークスよりも強度の高いコークスが製造できる。 In the blending step, the low-grade coal modified in the holding step is blended with a part or all of the blended coal used when producing the coke. The coal blend is then adjusted to a particle size and water content suitable for coke production. The low-grade coal retained in the immersion water in the retaining step has calcium, magnesium, iron, etc. removed and improved caking properties, so by using the low-grade coal as blended coal to produce coke. It is possible to produce a coke having a higher strength than the coke produced using the blended coal blended with the low-grade coal having an improved caking property.
また、酸滲出石炭も通常の原料炭と同じくコークスの製造に用いることができるので、配合ステップでは、保持ステップで浸漬水中に保持された低品位炭とともに酸滲出石炭を配合炭に配合してもよい。低品位炭とともに酸滲出石炭を配合炭に配合することで、保持ステップで酸滲出石炭と低品位炭を混合して浸漬水中に保持させた場合においても、酸滲出石炭と低品位炭とを分離することなく配合炭に配合できる。コークス製造ステップでは、配合ステップで配合された配合炭をコークス炉に装炭し、乾留してコークスを製造する。 Further, since acid-leached coal can be used for the production of coke as with ordinary coking coal, in the blending step, even if the acid-leached coal is blended in the blended coal with the low-grade coal held in the immersion water in the holding step. Good. By mixing acid-leached coal with blended coal together with low-grade coal, the acid-leached coal and low-grade coal are separated even when the acid-leached coal and low-grade coal are mixed and held in the immersion water in the holding step. Can be blended into blended coal without doing. In the coke production step, the blended coal blended in the blending step is charged into a coke oven and carbonized to produce coke.
次に、酸性溶液中に石炭を保持することで改質し、当該改質された石炭を用いて製造されたコークスのコークス強度を確認した実験について説明する。容器にｐＨ３．８の塩酸溶液を１Ｌ入れ、当該塩酸溶液に石炭２２０ｇを完全に浸漬させた。塩酸溶液の質量は石炭質量の約４．５倍であった。使用した石炭は、表１における石炭Ｊおよび石炭Ｎである。石炭Ｊおよび石炭Ｎの石炭性状を下記表２に示す。なお、石炭Ｊおよび石炭Ｎは、酸滲出石炭ではない。 Next, description will be made on an experiment in which coal was modified by holding it in an acidic solution and the coke strength of the coke produced by using the modified coal was confirmed. 1 L of a hydrochloric acid solution having a pH of 3.8 was put in the container, and 220 g of coal was completely immersed in the hydrochloric acid solution. The mass of the hydrochloric acid solution was about 4.5 times the mass of coal. The coals used were coal J and coal N in Table 1. The coal properties of Coal J and Coal N are shown in Table 2 below. Coal J and coal N are not acid-leached coals.
塩酸溶液に石炭Ｊまたは石炭Ｎを浸漬させた時点を保持時間０とし、所定時間経過するごとに容器内から石炭の一部を取り出すことで、塩酸溶液中に保持する保持時間を変えた石炭を調整した。このように塩酸溶液に保持する時間を変えた石炭を、直径２０ｍｍ、高さ１０ｍｍの円筒状容器に充填密度が８００ｋｇ／ｍ３となるように充填し、加熱温度１０５０℃で６時間乾留してコークス化し、得られた円柱状のコークスの間接引張強度を測定した。間接引張強度は、非特許文献４に記載された方法で測定した。 The holding time is set to 0 when the coal J or coal N is immersed in the hydrochloric acid solution, and a portion of the coal is taken out from the container every time a predetermined time elapses. It was adjusted. In this way, the coal, which was kept in the hydrochloric acid solution for different times, was filled into a cylindrical container having a diameter of 20 mm and a height of 10 mm so that the packing density was 800 kg/m 3, and the carbon was distilled at a heating temperature of 1050° C. for 6 hours. The coke was made into coke, and the indirect tensile strength of the obtained columnar coke was measured. The indirect tensile strength was measured by the method described in Non-Patent Document 4.
図３は、塩酸溶液に保持した保持時間とコークスの間接引張強度との関係を示すグラフである。図３において、縦軸はコークスの間接引張強度（ＭＰａ）であり、横軸は保持時間（ｈ）である。図３に示すように、石炭Ｎおよび石炭Ｊの何れも保持時間１０時間迄は、塩酸溶液に保持する時間の増加に伴ってコークスの間接引張強度は向上した。一方、保持時間が１０時間を超えると、石炭が酸化され、コークスの間接引張強度は低下し始めるが、保持時間が１４日の石炭Ｊを用いて製造されたコークスの間接引張強度は、塩酸溶液に保持されていない石炭Ｊを用いて製造されたコークスの間接引張強度よりもわずかに高かった。このため、酸性溶液に保持する保持時間は、１時間以上１４日以下の範囲内であればよく、当該範囲内で酸性溶液に保持された石炭を用いて製造されたコークスの強度は、酸性溶液に保持されていない石炭を用いて製造されたコークスよりも高くなる。なお、図３から、酸性溶液に保持する保持時間は、１時間以上１０時間以下であることがより好ましいことがわかる。 FIG. 3 is a graph showing the relationship between the holding time of the coke and the indirect tensile strength of the coke. In FIG. 3, the vertical axis represents the indirect tensile strength of coke (MPa), and the horizontal axis represents the holding time (h). As shown in FIG. 3, the indirect tensile strength of the coke improved with the increase in the time of holding in the hydrochloric acid solution for both coal N and coal J until the holding time of 10 hours. On the other hand, when the holding time exceeds 10 hours, the coal is oxidized and the indirect tensile strength of the coke begins to decrease. However, the indirect tensile strength of the coke produced using the coal J of 14 days has a hydrochloric acid solution. It was slightly higher than the indirect tensile strength of coke made with Coal J not retained in. Therefore, the holding time for holding in the acidic solution may be in the range of 1 hour or more and 14 days or less, and the strength of the coke produced using the coal held in the acidic solution within the range is the same as that of the acidic solution. Higher than coke made with coal not retained in. From FIG. 3, it can be seen that the holding time for holding in the acidic solution is more preferably 1 hour or more and 10 hours or less.
図３に示した実験結果から、石炭を酸性溶液中に保持することで石炭が改質され、当該改質された石炭を用いてコークスを製造することで、改質されていない石炭を用いて製造されたコークスよりも高い強度のコークスが製造できることが確認された。 From the experimental results shown in FIG. 3, by holding the coal in an acidic solution, the coal was reformed, and by using the reformed coal to produce coke, unmodified coal was used. It was confirmed that coke having a higher strength than the coke produced can be produced.
なお、本実施形態では、酸滲出石炭とともに水中に保持する石炭を低品位炭としたが、これに限られない。酸滲出石炭とともに浸漬する石炭は低品位炭でなくてもよく、コークスの製造に用いられる原料炭であればよい。これら原料炭も、酸性溶液に浸漬されることでカルシウム、マグネシウムおよび鉄などの成分が取り除かれるので、当該原料炭の粘結性は向上し、当該原料炭を含む配合炭を用いて製造されたコークスの強度は向上する。 In the present embodiment, the coal retained in water together with the acid-leached coal is low-grade coal, but the present invention is not limited to this. The coal that is dipped with the acid-leached coal does not have to be low-grade coal, and may be raw coal used for coke production. Since these raw coals are also immersed in an acidic solution to remove components such as calcium, magnesium and iron, the caking properties of the raw coals are improved, and the raw coals were produced using blended coals containing the raw coals. The coke strength is improved.
次に、実施例を説明する。表１の石炭Ｃおよび石炭Ｌを用い、これら石炭それぞれ１５０ｇを純水が入った容器Ａに浸漬させるとともに、容器Ａの上部を石炭が通過できないろ紙で覆った。表１から石炭Ｃおよび石炭Ｌは、水に浸漬させた浸漬水のｐＨが７．０未満である酸滲出石炭である。 Next, examples will be described. Using coal C and coal L in Table 1, 150 g of each of these coals was immersed in a container A containing pure water, and the upper part of the container A was covered with a filter paper through which coal could not pass. From Table 1, coal C and coal L are acid-leached coals having a pH of immersion water immersed in water of less than 7.0.
容器Ａよりも大きな容器Ｂに純水を入れ、石炭Ｃまたは石炭Ｌを浸漬させた容器Ａと石炭Ｉとを容器Ｂの純水中に入れた。容器Ａの上部のろ紙が、容器Ｂの純水に完全に浸漬するまで容器Ａを容器Ｂに浸漬させた。容器Ａおよび容器Ｂに入れた純水の合計体積は０．９５Ｌであり、純水の合計質量は全石炭質量の約３．２倍である。容器Ａの石炭と容器Ｂの石炭とは、容器Ａ、容器Ｂおよびろ紙で仕切られている。このため、石炭Ｃまたは石炭Ｌと、石炭Ｉとは直接接触せず、水のみがろ紙を通過して容器Ａと容器Ｂとの間を移動する。 Pure water was put into a container B larger than the container A, and the container A and the coal I in which the coal C or the coal L was immersed were put into the pure water of the container B. The container A was immersed in the container B until the filter paper on the upper part of the container A was completely immersed in the pure water in the container B. The total volume of pure water in the containers A and B was 0.95 L, and the total mass of pure water was about 3.2 times the total mass of coal. The coal in container A and the coal in container B are separated by container A, container B, and filter paper. Therefore, the coal C or the coal L and the coal I do not come into direct contact with each other, and only water moves between the container A and the container B through the filter paper.
このように構成された装置を用いて、石炭Ｃまたは石炭Ｌと、石炭Ｉとを水中に保持する効果を確認した。石炭Ｃ、石炭Ｌおよび石炭Ｉの石炭性状を下記表３に示す。 The effect of holding coal C or coal L and coal I in water was confirmed using the apparatus configured in this way. The coal properties of Coal C, Coal L and Coal I are shown in Table 3 below.
容器Ａおよび石炭Ｉを容器Ｂに完全に浸漬させた時点を保持時間０とし、所定時間経過するごとに容器Ｂから浸漬水と石炭Ｉの一部を取り出すことで、保持時間を変えた浸漬水と石炭Ｉとを採取した。ＩＣＰ発光分析を用いて採取した浸漬水のカルシウムイオンおよびマグネシウムイオン濃度を測定した。採取した石炭Ｉを直径２０ｍｍ、高さ１０ｍｍの円筒状容器に充填密度が８００ｋｇ／ｍ３となるように充填し、加熱温度１０５０℃で６時間乾留してコークス化し、得られた円柱状のコークスの間接引張強度を非特許文献４に記載された方法で測定した。 The holding time is 0 when the container A and the coal I are completely immersed in the container B, and the immersion water and a part of the coal I are taken out from the container B every time a predetermined time elapses. And coal I were collected. The calcium ion and magnesium ion concentrations of the soaked water collected were measured using ICP emission spectrometry. The collected coal I was filled in a cylindrical container having a diameter of 20 mm and a height of 10 mm so that the packing density would be 800 kg/m 3, and was carbonized at a heating temperature of 1050° C. for 6 hours to form coke, and the obtained columnar coke Was measured by the method described in Non-Patent Document 4.
図４は、容器Ｂに保持した保持時間と浸漬水のカルシウムイオンとマグネシウムイオンとを合算した濃度との関係を示すグラフである。図４において、縦軸はカルシウムイオンとマグネシウムイオンとを合算した濃度（以後、カルシウムイオン＋マグネシウムイオン濃度と記載する）（ｍｇ／Ｌ）であり、横軸は保持時間（ｈ）である。図４に示すように、酸滲出石炭である石炭Ｃまたは石炭Ｌを浸漬させた浸漬水では、保持時間とともにカルシウムイオン＋マグネシウムイオン濃度が高くなった。このことから、酸滲出石炭である石炭Ｃまたは石炭Ｌから滲出した酸によって石炭に含まれるカルシウムおよびマグネシウムが脱離することが確認された。 FIG. 4 is a graph showing the relationship between the holding time of the container B and the concentration of calcium ions and magnesium ions in the immersion water. In FIG. 4, the vertical axis represents the concentration of calcium ions and magnesium ions (hereinafter referred to as calcium ion+magnesium ion concentration) (mg/L), and the horizontal axis represents the retention time (h). As shown in FIG. 4, in the immersion water in which coal C or coal L, which is acid-leached coal, was immersed, the calcium ion+magnesium ion concentration increased with the holding time. From this, it was confirmed that calcium and magnesium contained in coal are desorbed by the acid leached from coal C or coal L which is acid-leached coal.
図５は、浸漬水に保持した保持時間とコークスの間接引張強度との関係を示すグラフである。図５において、縦軸は間接引張強度であり、横軸は保持時間（ｈ）である。なお、図５の横軸は対数軸であるため、保持時間０ｈの場合のデータを便宜的に０．１ｈの位置にプロットしている。図５に示すように、酸滲出石炭である石炭Ｃ、石炭Ｌを用いた場合は、保持時間の増加に伴い、石炭Ｉを用いて製造されたコークスの間接引張強度は向上した。 FIG. 5 is a graph showing the relationship between the holding time held in immersion water and the indirect tensile strength of coke. In FIG. 5, the vertical axis represents indirect tensile strength and the horizontal axis represents holding time (h). Since the horizontal axis of FIG. 5 is a logarithmic axis, the data when the holding time is 0 h is plotted at the position of 0.1 h for convenience. As shown in FIG. 5, in the case of using the acid-leached coals C and L, the indirect tensile strength of the coke produced using the coal I was improved as the holding time was increased.
比較例として、酸滲出石炭ではない石炭Ｍを用いて実施例と同じ条件で石炭Ｍと石炭Ｉとを水中に保持し、その効果を確認した。石炭Ｍの石炭性状を下記表４に示す。 As a comparative example, coal M and coal I, which were not acid-leached coals, were held in water under the same conditions as in the examples, and the effect was confirmed. The coal properties of Coal M are shown in Table 4 below.
図５に示すように、酸滲出石炭ではない石炭Ｍを用いた場合には、石炭Ｉを用いて製造されたコークスの間接引張強度は向上しなかった。このように、酸滲出石炭である石炭Ｃまたは石炭Ｌと、酸滲出石炭ではない石炭Ｉとを水に保持することで石炭Ｉを改質でき、当該石炭Ｉを用いることで、改質されていない保持時間０の石炭Ｉを用いて製造されたコークスよりも高い強度のコークスが製造できることが確認された。また、約１４日間改質された石炭Ｉと、改質されていない石炭Ｉを１：１で配合した配合炭から製造したコークスの強度は２．５ＭＰａとなり、Ｉ炭のみを乾留した場合と同様、保持時間０の場合に比較して高い強度のコークスが製造できた。 As shown in FIG. 5, when the coal M which is not the acid-leached coal was used, the indirect tensile strength of the coke produced using the coal I was not improved. In this way, the coal I can be reformed by holding the coal C or the coal L which is the acid-leached coal and the coal I which is not the acid-leached coal in water, and the coal I is reformed by using the coal I. It was confirmed that higher strength coke could be produced than coke produced using coal I with no holding time of 0. Further, the strength of the coke produced from the blended coal in which the reformed coal I and unmodified coal I were blended at a ratio of 1:1 for about 14 days was 2.5 MPa, which is the same as when carbonizing only the I coal. , A coke having a higher strength than the case where the holding time was 0 could be produced.
なお、本実施例で石炭Ｉを改質した石炭Ｃおよび石炭Ｌは、図２から、４００ｍｌの水に５０ｇの石炭を浸漬させた場合に当該浸漬水のｐＨが４．０以下となる石炭である。酸滲出石炭としては、浸漬水のｐＨが７．０未満となる石炭であれば低品位炭を改質する効果が得られるが、石炭Ｃおよび石炭ＬのようにｐＨが４．０以下となる酸滲出石炭を用いることがより好ましい。 It should be noted that the coal C and the coal L obtained by modifying the coal I in this example are coals in which the pH of the immersion water becomes 4.0 or less when 50 g of coal is immersed in 400 ml of water from FIG. is there. As the acid-leached coal, if the immersion water has a pH of less than 7.0, the effect of reforming the low-grade coal can be obtained, but as with the coal C and the coal L, the pH becomes 4.0 or less. More preferably, acid-leached coal is used.
浸漬水のｐＨや硫酸イオン濃度は、浸漬する石炭の質量や、浸漬する純水の量に影響される値である。これらの影響を除くために、ｐＨ（水素イオン濃度）または硫酸イオン濃度に浸漬水の体積を乗じ、浸漬させた石炭の質量で除した石炭１ｇあたりの水素イオンのモル数または硫酸イオン量で酸滲出石炭を定義することが好ましい。 The pH of the immersion water and the sulfate ion concentration are values that are affected by the mass of the coal to be immersed and the amount of pure water to be immersed. In order to eliminate these effects, the pH (hydrogen ion concentration) or sulfate ion concentration is multiplied by the volume of immersion water, and the number of moles of hydrogen ions per 1 g of coal divided by the mass of immersed coal or the amount of sulfate ions It is preferred to define exuded coal.
図２に示すように、石炭Ｃおよび石炭Ｌのように浸漬水のｐＨが４．０以下となる石炭は、浸漬水における石炭１ｇあたりの水素イオンのモル数で８．０×１０−７ｍоｌ／ｇ以上となる石炭である。このため、浸漬水における石炭１ｇあたりの水素イオンのモル数で８．０×１０−７ｍоｌ／ｇ以上となる酸滲出石炭を用いることが好ましい。 As shown in FIG. 2, coals such as coal C and coal L in which the pH of the immersion water is 4.0 or less are 8.0×10 −7 mol per mol of hydrogen ion in the immersion water. /G or more coal. For this reason, it is preferable to use acid-leached coal in which the number of moles of hydrogen ions per 1 g of coal in the immersion water is 8.0×10 −7 mol/g or more.
また、図２に示すように、浸漬水のｐＨが４．０以下となる石炭Ｃおよび石炭Ｌは、４００ｍｌの水に５０ｇの石炭を浸漬させた場合に当該浸漬水の硫酸イオン濃度が５０．０ｍｇ／Ｌ以上となる石炭である。硫酸イオン濃度５０．０ｍｇ／Ｌは、石炭１ｇあたりの浸漬水の硫酸イオン量０．４ｍｇ／ｇに相当するので、石炭１ｇあたりの浸漬水の硫酸イオン量が０．４ｍｇ／ｇ以上となる酸滲出石炭を用いることが好ましい。 Further, as shown in FIG. 2, when the immersion water has a pH of 4.0 or less, coal C and coal L have a sulfate ion concentration of 50.50 when the 50 g of coal is immersed in 400 ml of water. It is a coal of 0 mg/L or more. Since the sulfate ion concentration of 50.0 mg/L corresponds to the sulfate ion amount of 0.4 mg/g of the immersion water per 1 g of coal, an acid whose sulfate ion amount of the immersion water per 1 g of coal is 0.4 mg/g or more It is preferred to use exuded coal.
また、本実施例において、酸滲出石炭である石炭Ｃおよび石炭Ｌと、改質する石炭Ｉとの質量比を１：１とした。保持ステップで水に保持する石炭Ｃおよび石炭Ｌの質量が改質する石炭Ｉの質量以上であれば、本実施例で確認された以上の改質効果が得られるので、石炭Ｃまたは石炭Ｌの質量（酸滲出石炭質量）と石炭Ｉの質量（他の石炭の質量）は、下記（１）式を満足することが好ましいといえる。 Further, in the present example, the mass ratio between the coal C and the coal L, which are acid-leached coals, and the coal I to be reformed was set to 1:1. If the mass of the coal C and the coal L held in the water in the holding step is equal to or more than the mass of the coal I to be reformed, the above-described reforming effect confirmed in this example can be obtained. It can be said that the mass (mass of acid-leached coal) and the mass of coal I (mass of other coal) preferably satisfy the following formula (1).
酸滲出石炭の質量／他の石炭の質量≧１・・・（１） Mass of acid-leached coal/mass of other coal ≧1...(1)
以上説明したように、本実施形態に係るコークスの製造方法を実施することで、改質剤および酸性溶液を新たに用いることなく、水に石炭を浸漬させるという単純なプロセスで石炭を改質でき、当該改質された石炭を用いて高強度なコークスを製造できることが確認された。 As described above, by carrying out the coke production method according to the present embodiment, coal can be reformed by a simple process of immersing coal in water without newly using a modifier and an acidic solution. It was confirmed that high-strength coke can be produced using the modified coal.
Claims (6)
前記保持ステップで水に保持された他の石炭を、コークスを製造する際に用いる配合炭の一部または全部に配合する配合ステップと、
前記配合ステップで配合された前記配合炭をコークス炉で乾留するコークス製造ステップと、を含む、コークスの製造方法。 A holding step of holding in water the acid-leached coal and another coal in which the immersion water immersed in water has a pH of less than 7.0;
Other coal held in water in the holding step, a blending step of blending a part or all of the coal blend used in the production of coke,
A coke production step of dry-distilling the blended coal blended in the blending step in a coke oven.
酸滲出石炭の質量／他の石炭の質量≧１・・・（１） The mass of the acid-leached coal held in water and the mass of the other coal in the holding step satisfy the following formula (1), wherein the coke according to any one of claims 1 to 3 is used. Production method.
Mass of acid-leached coal/mass of other coal ≧1...(1)
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