JP6874502B2 - Coke strength estimation method - Google Patents
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本発明は、膨張性を有さない劣質炭が配合された配合炭を用いて製造される高炉用コークスの強度を推定する方法に関する。 The present invention relates to a method for estimating the strength of coke for a blast furnace produced by using a blended coal containing a non-expandable inferior coal.
高炉の通気性を確保し、安定的に操業するために、高炉で用いられるコークスには、所要の強度が求められる。近年、高炉容積の大型化やＣＯ2削減を目指して低還元材比で操業するために、益々高強度のコークスが求められている。 The coke used in the blast furnace is required to have the required strength in order to ensure the air permeability of the blast furnace and to operate it stably. In recent years, more and more high-strength coke has been required in order to operate with a low reducing agent ratio with the aim of increasing the volume of the blast furnace and reducing CO 2.
高炉用コークスを製造する際には、多種多様な銘柄の石炭を配合した原料石炭（配合炭）をコークス炉内に装入し、乾留する。コークス炉の中で加熱された配合炭は、３５０〜５００℃の温度域で一旦軟化溶融・膨張して、石炭粒子同士が結合した後、再度固化することで、コークスを生成する。 When producing coke for a blast furnace, raw material coal (blended coal) containing a wide variety of brands of coal is charged into the coke oven and carbonized. The compound coal heated in the coke oven is once softened, melted and expanded in a temperature range of 350 to 500 ° C., the coal particles are bonded to each other, and then solidified again to generate coke.
石炭が軟化溶融する性質のことを粘結性といい、配合炭は、通常、粘結性の高い石炭（粘結炭）と粘結性の低い石炭（非微粘結炭）が十数種類配合された構成となっている。なお、粘結炭は高石炭化度炭であり、非微粘結炭は全てが低石炭化度炭とは限らないが、低石炭化度炭が多い。 The property of softening and melting coal is called cohesiveness, and compound coal usually contains more than a dozen types of coal with high cohesiveness (coal caking) and coal with low cohesiveness (non-slightly coagulating coal). It has a structure that has been set. The caking coal is a high-coalization degree coal, and not all non-slightly caking coals are low-coalization degree coals, but most of them are low-coalization degree coals.
強度の高いコークスを製造するには、配合炭に一定の粘結性が必要とされることから、粘結炭を多く配合することが必要である。しかし、良質な粘結炭は高価であり、また資源的に枯渇状態にあるのに対して、粘結性の劣る非微粘結炭は、埋蔵量が豊富であり、安価に入手できることから、非微粘結炭の配合率を高くすることが望まれている。更に、より劣質な非微粘結炭を配合する傾向が近年強まっている。 In order to produce high-strength coke, it is necessary to add a large amount of caking coal because the compounded coal needs to have a certain degree of caking property. However, good quality caking coal is expensive and depleted in terms of resources, whereas non-slightly caking coal, which has poor caking properties, has abundant reserves and can be obtained at low cost. It is desired to increase the blending ratio of non-slightly caking coal. Furthermore, there has been an increasing tendency in recent years to blend inferior non-slightly caking coal.
しかし、粘結性に乏しい非微粘結炭を配合すると、上記のコークス化機構から理解されるように、石炭粒子の膨張及び結合が不十分となり、コークス強度の低下を招く。コークス強度の低下は、高炉操業に多大なる影響を及ぼすため、配合する石炭の性状から事前にコークス強度を予測する技術は、粘結性に乏しい非微粘結炭を配合する、現在の石炭配合事情において非常に重要である。 However, when non-slightly caking coal having poor cohesiveness is blended, as can be understood from the above-mentioned coking mechanism, the expansion and bonding of coal particles become insufficient, resulting in a decrease in coke strength. Since a decrease in coke strength has a great impact on blast furnace operation, the technology for predicting coke strength in advance from the properties of the coal to be blended is the current coal blending, which blends non-slightly caking coal with poor cohesiveness. Very important in the circumstances.
一方、コークス強度の指標として、ＪＩＳ Ｋ２１５１に記載のドラム強度が使用されている。ドラム強度は、所定量のコークス（１０ｋｇ）を装入した回転ドラムを１５０回転させた後、篩目１５ｍｍの篩でふるい分けた篩上（粒径１５ｍｍ超）のコークス質量の全装入コークス質量に対する百分率（１５ｍｍ指数）で評価するものであり、ＤＩ150 15と表記している。 On the other hand, the drum strength described in JIS K2151 is used as an index of coke strength. The drum strength is the total coke mass on the sieve (grain size over 15 mm) sieved with a sieve having a mesh size of 15 mm after rotating a rotating drum charged with a predetermined amount of coke (10 kg) 150 times. It is evaluated by a percentage (15 mm index) and is described as DI 150 15 .
また、ドラム回転時に発生する篩目１５ｍｍの篩でふるい分けた篩下（粒径１５ｍｍ以下）の粉には、表面破壊により生成する粉（表面破壊粉：粒径６ｍｍ以下）及び体積破壊により生成する粉（体積破壊粉：粒径６−１５ｍｍ）が混在していることも明らかにされている。
In addition, the powder under the sieve (
表面破壊は、平均粒度１ｍｍ程度に粉砕された原料石炭の軟化溶融・膨張が不十分なことに起因し、原料石炭の粒子同士の不完全な接着や、装炭時の原料石炭の粒子間空隙の不十分な充填が、欠陥としてコークス中に残存することにより生じる。また、体積破壊は、コークス全体の収縮の不均一さから発生する熱応力によって生成する亀裂により生じ、その生成量は、コークス炉内の温度分布やコークス収縮係数（単位温度あたりの収縮量の大小）に影響される。 Surface destruction is caused by insufficient softening, melting, and expansion of the raw material coal crushed to an average particle size of about 1 mm, resulting in incomplete adhesion between the particles of the raw material coal and interparticle voids of the raw material coal during coal loading. Inadequate filling of the coal is caused by remaining in the coke as defects. In addition, volumetric fracture is caused by cracks generated by thermal stress generated from the non-uniform shrinkage of the entire coke, and the amount of the cracks generated is the temperature distribution in the coke oven and the coke shrinkage coefficient (the magnitude of the shrinkage amount per unit temperature). ) Is affected.
このような、表面破壊に関する強度（表面破壊強度）及び体積破壊に関する強度（体積破壊強度）を個々に求めることで、コークス強度ＤＩ150 15を推定する方法が知られている。
例えば、特許文献１には、石炭の膨張比容積と装入嵩密度から石炭軟化溶融時の空隙充填度を求め、この空隙充填度からコークスの表面破壊強度を推定する方法が開示されている。また、コークスの表面破壊強度を推定するに際し、石炭軟化時の膨張比容積は、配合炭の場合、各石炭の実測値の加重平均値を用いればよいとされている。
A method of estimating the coke strength DI 150 15 is known by individually determining the strength related to surface fracture (surface fracture strength) and the strength related to volume fracture (volume fracture strength).
For example, Patent Document 1 discloses a method of obtaining the void filling degree at the time of softening and melting coal from the expansion specific volume of coal and the charging bulk density, and estimating the surface fracture strength of coke from the void filling degree. Further, when estimating the surface fracture strength of coke, in the case of compound coal, the weighted average value of the measured values of each coal may be used as the expansion specific volume at the time of coal softening.
なお、表面破壊強度とは、ドラム強度の６ｍｍ指数（ＤＩ150 6）、すなわちドラムを１５０回転させた後の篩目６ｍｍの篩でふるい分けた篩上（粒径６ｍｍ超）のコークス質量の全装入コークス質量に対する百分率である。以下では、表面破壊強度をＤＩ150 6と表記することがある。
The surface breaking strength is a 6 mm index of drum strength (DI 150 6 ), that is, the total coke mass on the sieve (grain size over 6 mm) sieved with a sieve having a mesh size of 6 mm after rotating the
しかしながら、非微粘結炭の配合割合が増大すると、石炭の膨張比容積には加成性が成立しないため、特許文献１に開示の方法では、十分な正確性で表面破壊強度を推定できないことがあった。 However, when the blending ratio of the non-slightly caking coal increases, the expansion specific volume of the coal is not additive, so that the method disclosed in Patent Document 1 cannot estimate the surface fracture strength with sufficient accuracy. was there.
そこで、特許文献２では、高石炭化度炭（粘結炭）と、低石炭化度炭（非微粘結炭）のそれぞれに基づく表面破壊強度を、それぞれの膨張比容積と装入嵩密度から推定し、これらを高石炭化度炭と低石炭化度炭の配合割合で加重平均することにより、コークスの表面破壊強度を推定する方法が開示されている。
Therefore, in
また、特許文献３では、膨張性を有しない低石炭化度炭を配合炭の一部に用いて製造するコークスの表面破壊強度の推定をするにあたり、３℃／分以上の昇温速度で測定した低石炭化度炭の膨張比容積の値を用いて粘結炭の表面破壊強度に関するイナートファクターを求め、これを用いて粘結炭の表面破壊強度の推定値を算出し、低石炭化度炭の表面破壊強度の推定値を用いて、配合炭中の粘結炭と低石炭化度炭の配合割合で加重平均することにより、コークスの表面破壊強度を推定する方法が開示されている。 Further, in Patent Document 3, in estimating the surface breaking strength of coke produced by using low coalification coal having no expandability as a part of the blended coal, it is measured at a temperature rising rate of 3 ° C./min or more. The inertia factor for the surface breaking strength of the caking coal was obtained using the value of the expansion ratio volume of the low coal conversion coal, and the estimated value of the surface breaking strength of the caking coal was calculated using this to calculate the low coalification degree. A method of estimating the surface breaking strength of coke by weight averaging the blending ratio of caking coal and low-coalization coal in the blended coal using the estimated value of the surface breaking strength of coal is disclosed.
特許文献２に開示の方法は、コークスの表面破壊強度の推定において有効な技術である。しかし、ＪＩＳ ８８０１に規定されているジラトメータにより測定される全膨張率が０％である粘結性を僅かしか有さない非微粘結炭（以下、「劣質炭」という）を配合した配合炭において、膨張比容積と装入嵩密度の積から求められた空隙充填度を用いて、コークスの表面破壊強度を推定したところ、十分な正確性で推定できないことがあった。
The method disclosed in
特許文献３に開示の手法は、ＪＩＳ ８８０１に規定されているジラトメータにより測定される全膨張率が０％である低石炭化度炭、所謂劣質炭を配合炭の一部に用いる際のコークス表面破壊強度推定において有効な手法であるが、劣質炭の配合率が多い場合や３℃／分以上の昇温速度で測定した膨張比容積が著しく低い銘柄を用いた場合などは、十分な正確性で推定できないことがあった。 The method disclosed in Patent Document 3 is a coke surface when low coalification coal, so-called inferior coal, having a total expansion ratio of 0% measured by a dilatometer specified in JIS 8801 is used as a part of the blended coal. This is an effective method for estimating fracture strength, but it is sufficiently accurate when the blending ratio of inferior coal is high or when a brand with a significantly low expansion specific volume measured at a temperature rise rate of 3 ° C / min or higher is used. There was something that could not be estimated.
本発明は、このような実情に鑑み、劣質炭を多く配合した配合炭や、膨張比容積が著しく低い劣質炭を配合した配合炭を用いて製造するコークスであっても、その表面破壊強度を正確に推定する方法を提供することを課題とする。 In view of such circumstances, the present invention can determine the surface fracture strength of coke produced by using a blended coal containing a large amount of inferior coal or a blended coal containing a poor quality coal having an extremely low expansion specific volume. An object of the present invention is to provide a method for accurate estimation.
本発明者らは、上記課題を解決する手段について鋭意検討した。劣質炭は、全膨張率が０％であるため、膨張性では劣質炭同士を区別することができない。そこで、３℃／分よりも高い昇温速度で劣質炭の膨張比容積（以下、「高速昇温膨張比容積」という）を測定して、劣質炭同士を区別した。 The present inventors have diligently studied means for solving the above problems. Since the total expansion rate of the inferior coal is 0%, the inferior coal cannot be distinguished from each other in terms of expandability. Therefore, the expansion specific volume of the inferior coal (hereinafter referred to as "high-speed heating expansion specific volume") was measured at a heating rate higher than 3 ° C./min to distinguish the inferior coals from each other.
そして、非微粘結炭と劣質炭とを配合した劣質な石炭中の劣質炭の配合率及び劣質炭の高速昇温膨張比容積に対する、表面破壊強度の実測値と推定値との誤差について調査したところ、高速昇温膨張比容積が低いほど、また劣質炭の配合率が高いほど、誤差が大きくなることを知見し、その誤差を解消する手段についてさらに検討した。 Then, the error between the measured value and the estimated value of the surface fracture strength with respect to the mixing ratio of the inferior coal in the inferior coal in which the non-slightly caking coal and the inferior coal are mixed and the high-speed temperature rising expansion ratio volume of the inferior coal is investigated. As a result, it was found that the lower the high-speed heating / expansion ratio volume and the higher the blending ratio of the inferior coal, the larger the error, and the means for eliminating the error was further investigated.
そこで、高速昇温膨張比容積が後述の閾値（Ｔ）よりも大きい石炭を用いた場合は、予め、劣質炭の高速昇温膨張比容積及び劣質な石炭中の劣質炭の配合率を強度発現阻害要因とする劣質炭に関する粒子間接着影響（補正値）の関係を求めておき、用いる劣質炭の高速昇温膨張比容積及び劣質な石炭中の劣質炭の配合率と、該関係から補正値を求め、劣質な石炭に基づく表面破壊強度の推定値から該補正値を減じたところ、コークスの表面破壊強度を正確に推定できることを見出した。 Therefore, when coal having a high-speed heating / expansion ratio volume larger than the threshold value (T) described later is used, the high-speed heating / expansion ratio volume of the inferior coal and the blending ratio of the inferior coal in the inferior coal are expressed in advance. The relationship between the interparticle adhesion effect (correction value) on the inferior coal as an inhibitory factor is obtained, and the high-speed temperature rise / expansion ratio volume of the inferior coal used, the mixing ratio of the inferior coal in the inferior coal, and the correction value from the relationship. It was found that the surface breaking strength of coke can be accurately estimated by subtracting the correction value from the estimated value of the surface breaking strength based on inferior coal.
また、高速昇温膨張比容積が閾値（Ｔ）以下の低い石炭を用いた場合は、上記の補正値でも誤差が生じることが判明した。このため、前記の閾値（Ｔ）よりも低い石炭を用いた場合は、劣質炭の粘結力指数（ＣＩ）及び劣質な石炭中の劣質炭の配合率を強度発現阻害要因とする劣質炭に関する粒子間接着影響（補正値）の関係を求めておき、用いる劣質炭の粘結力指数（ＣＩ）及び劣質な石炭中の劣質炭の配合率と、該関係から補正値を求め、劣質な石炭に基づく表面破壊強度の推定値から該補正値を減じたところ、コークスの表面破壊強度を正確に推定できることを見出した。 Further, it was found that when coal having a low high-speed heating / expansion specific volume of the threshold value (T) or less was used, an error occurred even with the above correction value. Therefore, when coal lower than the above threshold (T) is used, the cohesive strength index (CI) of the inferior coal and the blending ratio of the inferior coal in the inferior coal are the factors that inhibit the development of strength. Obtain the relationship of the adhesion effect (correction value) between particles, and obtain the correction value from the cohesive strength index (CI) of the inferior coal to be used, the mixing ratio of the inferior coal in the inferior coal, and the inferior coal. It was found that the surface breaking strength of coke can be accurately estimated by subtracting the correction value from the estimated value of the surface breaking strength based on.
このような検討を通してなされた本発明の要旨は、以下の通りである。
［１］ 劣質炭を配合した配合炭を用いて製造するコークスの表面破壊強度の推定方法において、
前記配合炭は、ビトリニット平均反射率Ｒｏが０.８％以上、ＪＩＳ Ｍ ８８０１で規定される方法によって測定される全膨張率が０％超の粘結炭、及び、劣質な石炭として、ビトリニット平均反射率Ｒｏが０.８％未満で当該全膨張率が０％超の非微粘結炭と当該全膨張率が０％の劣質炭からなり、
（ａ）予め、複数の粘結炭の膨張比容積と装入嵩密度との積から求められる空隙充填度と、得られるコークスの表面破壊強度との関係を求め、
（ｂ）予め、複数の非微粘結炭と劣質炭とを配合した劣質な石炭の膨張比容積と装入嵩密度との積から求められる空隙充填度と、得られるコークスの表面破壊強度との関係を求め、
（ｃ）予め、劣質炭の強度発現阻害要因と粒子間接着影響の補正値との関係を以下のようにして求め、
（c1）劣質炭を３℃／分よりも高い所定の昇温速度で昇温したときの膨張比容積を高速昇温膨張比容積ＳV’として測定し、
（c2）測定した劣質炭の膨張比容積ＳV’が閾値Ｔよりも大きい場合、予め、当該膨張比容積ＳV’と劣質な石炭中の当該劣質炭の配合率とを強度発現阻害要因とし、その要因に基づく劣質炭に関する粒子間接着影響を表す補正値１との関係を求め、
（c3）測定した劣質炭の膨張比容積ＳV’が前記閾値Ｔ以下の場合、さらに当該劣質炭の粘結力指数ＣＩを測定し、予め、測定した粘結力指数ＣＩと劣質な石炭中の当該劣質炭の配合率とを強度発現阻害要因とし、その要因に基づく劣質炭に関する粒子間接着影響を補正値２との関係を求め、
コークスの表面破壊強度の推定にあたり、
（ｄ）用いる配合炭中の粘結炭の空隙充填度を同様に求め、前記（ａ）の関係から当該粘結炭に基づく表面破壊強度の推定値を求め、
（ｅ）用いる配合炭中の劣質な石炭の空隙充填度を同様に求め、前記（ｂ）の関係から当該劣質な石炭に基づく表面破壊強度の推定値を求め、
（ｆ）用いる配合炭中の劣質炭の膨張比容積ＳV’を求め、前記閾値Ｔとの関係に応じて、以下のようにして補正値を求め、
（f1）用いる配合炭中の劣質炭の膨張比容積ＳV’が前記閾値Ｔよりも大きい場合は、当該膨張比容積ＳV’と劣質な石炭中の当該劣質炭の配合率を求め、前記（c2）の関係から補正値１を求め、
（f2）用いる配合炭中の劣質炭の膨張比容積ＳV’が前記閾値Ｔ以下の場合は、当該劣質炭の粘結力指数ＣＩと劣質な石炭中の当該劣質炭の配合率を求め、前記（c3）の関係から補正値２を求め、
（ｇ）前記（ｅ）で求めた劣質な石炭に基づく表面破壊強度の推定値から、劣質炭の膨張比容積ＳV’に応じて、前記（f1）または（f2）で求めた補正値１または補正値２を減じて劣質な石炭に基づく表面破壊強度の補正推定値を求め、
（ｈ）前記（ｄ）で求めた粘結炭に基づく表面破壊強度の推定値と、前記（ｇ）で求めた劣質な石炭に基づく表面破壊強度の補正推定値とを、用いる配合炭中の粘結炭と劣質な石炭の配合率で加重平均する
ことを特徴とするコークス表面破壊強度の推定方法。
The gist of the present invention made through such studies is as follows.
[1] In a method for estimating the surface fracture strength of coke produced using a blended coal containing inferior coal.
The compound coal has a Vitrinit average reflectance Ro of 0.8% or more, a caking coal having a total expansion coefficient of more than 0% measured by the method specified by JIS M 8801, and a Vitrinit average as a poor quality coal. It consists of non-slightly caking coal with a reflectance Ro of less than 0.8% and a total expansion rate of more than 0% and inferior coal with a total expansion rate of 0%.
(A) The relationship between the void filling degree obtained from the product of the expansion specific volume of a plurality of caking coals and the charged bulk density and the surface fracture strength of the obtained coke was obtained in advance.
(B) The void filling degree obtained from the product of the expansion specific volume and the charged bulk density of the inferior coal in which a plurality of non-slightly caking coals and the inferior coal are mixed in advance, and the surface fracture strength of the obtained coke. Seeking a relationship,
(C) The relationship between the factor that inhibits the strength development of inferior coal and the correction value of the effect of adhesion between particles is obtained in advance as follows.
(C1) The expansion specific volume when the inferior coal is heated at a predetermined temperature rising rate higher than 3 ° C./min is measured as the high-speed heating expansion specific volume SV'.
(C2) When the measured expansion specific volume SV'of the inferior coal is larger than the threshold value T, the expansion specific volume SV'and the mixing ratio of the inferior coal in the inferior coal are set as strength development inhibitory factors in advance. Find the relationship with the correction value 1 that represents the effect of adhesion between particles on poor quality coal based on factors.
(C3) When the measured expansion specific volume SV'of the inferior coal is equal to or less than the threshold value T, the cohesive force index CI of the inferior coal is further measured, and the cohesive force index CI measured in advance and the inferior coal The mixing ratio of the inferior coal was used as a factor for inhibiting the development of strength, and the relationship between the interparticle adhesion effect on the inferior coal based on that factor and the
In estimating the surface fracture strength of coke,
(D) The void filling degree of the caking coal in the compound coal to be used was obtained in the same manner, and the estimated value of the surface fracture strength based on the caking coal was obtained from the relationship of (a) above.
(E) The void filling degree of the inferior coal in the compound coal to be used was obtained in the same manner, and the estimated value of the surface fracture strength based on the inferior coal was obtained from the relation of the above (b).
(F) The expansion specific volume SV'of the inferior coal in the compound coal to be used was obtained, and the correction value was obtained as follows according to the relationship with the threshold value T.
(F1) When the expansion specific volume SV'of the inferior coal in the blended coal to be used is larger than the threshold value T, the blending ratio of the expansion specific volume SV'and the inferior coal in the inferior coal is obtained, and the above (c2) ), Find the correction value 1 and
(F2) When the expansion specific volume SV'of the inferior coal in the compound coal to be used is equal to or less than the threshold value T , the cohesive strength index CI of the inferior coal and the compounding ratio of the inferior coal in the inferior coal are obtained. Obtain the
(G) From the estimated value of surface fracture strength based on the inferior coal obtained in the above (e), the correction value 1 or the correction value 1 obtained in the above (f1) or (f2) according to the expansion specific volume SV'of the inferior coal. Subtract the
(H) The estimated value of the surface fracture strength based on the caking coal obtained in the above (d) and the corrected estimated value of the surface fracture strength based on the inferior coal obtained in the above (g) are used in the compound coal to be used. A method for estimating the surface fracture strength of coke, which is characterized by weighted averaging based on the blending ratio of caking coal and inferior coal.
［２］前記の３℃／分よりも高い所定の昇温速度が１２℃／分であり、その場合の高速昇温膨張比容積ＳＶ’の閾値Ｔが１．２０であることを特徴とする上記［１］に記載のコークス表面破壊強度の推定方法。 [2] A predetermined heating rate higher than the above 3 ° C./min is 12 ° C./min, and the threshold value T of the high-speed heating / expansion ratio volume SV'in that case is 1.20. The method for estimating the coke surface fracture strength according to the above [1].
本発明によれば、劣質炭に関する粒子間接着影響を補正値として、劣質な石炭に基づく表面破壊強度の推定値から減じるので、劣質炭を配合した配合炭を用いて製造するコークスの表面破壊強度を正確に推定することができる。 According to the present invention, the effect of interparticle adhesion on the inferior coal is used as a correction value and is subtracted from the estimated value of the surface fracture strength based on the inferior coal. Can be estimated accurately.
本発明のコークスの表面破壊強度の推定方法（以下、「本発明の推定法」という）は、粘結炭、非微粘結炭、及び、劣質炭とからなる配合炭を用いて製造するコークスの表面破壊強度の推定方法であり、
（i）粘結炭に基づく表面破壊強度の推定値を求め、
（ii）非微粘結炭と劣質炭とを配合した劣質な石炭に基づく表面破壊強度の推定値を求め、
（iii）劣質炭の高速昇温膨張比容積（ＳV’）が閾値（Ｔ）よりも大きい場合、劣質炭の高速昇温膨張比容積及び劣質な石炭中の配合率を求め、高速昇温膨張比容積及び劣質な石炭中の配合率を強度発現阻害要因とする劣質炭に関する粒子間接着影響の関係から補正値１を求め、
劣質炭の高速昇温膨張比容積（ＳV’）が閾値（Ｔ）以下の場合、劣質炭の粘結力指数（ＣＩ）及び劣質な石炭中の配合率を求め、劣質炭の粘結力指数（ＣＩ）及び劣質な石炭中の配合率を強度発現阻害要因とする劣質炭に関する粒子間接着影響の関係から補正値２を求め、
（iv）劣質な石炭に基づく表面破壊強度の推定値から補正値を減じて補正推定値を求め、
（v）粘結炭に基づく表面破壊強度の推定値と劣質な石炭に基づく表面破壊強度の補正推定値とを、粘結炭と劣質な石炭の配合率で加重平均する
ものである。
The method for estimating the surface fracture strength of coke of the present invention (hereinafter referred to as "estimation method of the present invention") is coke produced using a blended coal composed of caking coal, non-slightly caking coal, and inferior coal. It is a method of estimating the surface fracture strength of
(I) Obtain an estimate of surface fracture strength based on caking coal.
(Ii) Obtain an estimate of the surface fracture strength based on inferior coal, which is a mixture of non-slightly caking coal and inferior coal.
(Iii) When the high-speed temperature-increasing expansion ratio volume (SV') of the inferior coal is larger than the threshold value (T), the high-speed temperature-increasing expansion ratio volume of the inferior coal and the blending ratio in the inferior coal are obtained, and the high-speed temperature-increasing expansion The correction value 1 was obtained from the relationship between the interparticle adhesion effect on the inferior coal with the specific volume and the blending ratio in the inferior coal as factors that inhibit the development of strength.
When the high-speed temperature-increasing expansion ratio volume (SV') of the inferior coal is equal to or less than the threshold value (T), the cohesive strength index (CI) of the inferior coal and the blending ratio in the inferior coal are obtained, and the cohesive strength index of the inferior coal. The
(Iv) Obtain the corrected estimated value by subtracting the corrected value from the estimated value of surface fracture strength based on poor quality coal.
(V) The estimated value of surface fracture strength based on caking coal and the corrected estimated value of surface fracture strength based on inferior coal are weighted averaged by the mixing ratio of caking coal and inferior coal.
以下、本発明の推定法に至った検討の経緯について説明するとともに、本発明の推定法について説明する。
従来、表面破壊強度は、粘結炭と非微粘結炭のそれぞれについて、膨張比容積と装入嵩密度の積から求められた空隙充填度を用いて、それぞれに基づく表面破壊強度を推定し、粘結炭と非微粘結炭の配合率で加重平均することにより、推定されていた。石炭軟化時の膨張比容積ＳＶは、ＪＩＳ Ｍ８８０１の膨張性試験に用いるジラトメータ装置を用いた試験（昇温速度３℃／分）により、以下の（１）式で算出される。
Hereinafter, the background of the study leading to the estimation method of the present invention will be described, and the estimation method of the present invention will be described.
Conventionally, the surface fracture strength is estimated based on the void filling degree obtained from the product of the expansion specific volume and the charge bulk density for each of the caking coal and the non-slightly caking coal. , It was estimated by weighted averaging by the mixing ratio of caking coal and non-slightly caking coal. The expansion specific volume SV at the time of coal softening is calculated by the following equation (1) by a test (heating rate 3 ° C./min) using a dilatometer device used for the expansion test of JIS M8801.
膨張比容積ＳＶ［ｃｍ3／ｇ］＝最大膨張時の石炭体積［ｃｍ3］／石炭装入量［ｇ］
・・・（１）
Expansion specific volume SV [cm 3 / g] = coal volume at maximum expansion [cm 3 ] / coal charge [g]
... (1)
また、石炭軟化時の空隙充填度は、（１）式により求めた膨張比容積ＳＶと装入嵩密度ＢＤを用い、以下の（２）式から算出することができる。 Further, the void filling degree at the time of coal softening can be calculated from the following equation (2) using the expansion specific volume SV obtained by the equation (1) and the charging bulk density BD.
空隙充填度［−］＝膨張比容積ＳＶ［ｃｍ3／ｇ］×装入嵩密度ＢＤ［ｇ／ｃｍ3］
・・・（２）
Void filling degree [-] = expansion specific volume SV [cm 3 / g] x charging bulk density BD [g / cm 3 ]
... (2)
しかしながら、全膨張率が０％の劣質炭を配合した配合炭に対して、粘結炭と非微粘結炭（劣質炭を含む）のそれぞれに基づく表面破壊強度を推定し、粘結炭と非微粘結炭の配合率で加重平均することによりコークスの表面破壊強度を推定したところ、正確に推定できないことがあった。 However, the surface fracture strength based on each of the caking coal and the non-slightly caking coal (including the inferior coal) is estimated with respect to the blended coal containing the inferior coal having a total expansion rate of 0%, and the caking coal is used. When the surface fracture strength of coke was estimated by weight averaging with the blending ratio of non-slightly caking coal, it was sometimes not possible to estimate it accurately.
これは、全膨張率が０％の同じ劣質炭の括りの中でも、実際には僅かな粘結性の違いが存在し、接着不良の度合いが異なるためと考えた。すなわち、劣質炭の性状により、同一の配合率でも強度低下への影響が異なると考えた。 It was considered that this was because there was actually a slight difference in cohesiveness and the degree of poor adhesion was different even in the same inferior coal bundle with a total expansion rate of 0%. That is, it was considered that the effect on the decrease in strength differs depending on the properties of the inferior coal even if the blending ratio is the same.
そこで、３℃／分よりも高い昇温速度で劣質炭の高速昇温膨張比容積を求め、劣質炭同士を区別し、劣質炭間の性状の違いによる強度低下への影響について次のような試験を行った。 Therefore, the high-speed temperature-increasing expansion ratio volume of the inferior coal was obtained at a heating rate higher than 3 ° C./min, the inferior coals were distinguished from each other, and the effect on the strength decrease due to the difference in the properties between the inferior coals was as follows. The test was conducted.
まず、非微粘結炭及び４種の劣質炭を準備した。非微粘結炭のビトリニット平均反射率Ｒｏは０.７％である。表１に、非微粘結炭及び劣質炭の揮発分量ＶＭ、全膨張率ＴＤ、及び、高速昇温膨張比容積（ＳV’）を示す。
以下、揮発分ＶＭは、ＪＩＳ Ｍ８８１２で規定される方法、全膨張率ＴＤは、ＪＩＳ Ｍ ８８０１で規定される方法により測定したものを示す。高速昇温膨張比容積の測定法については、以下に簡潔に説明する。
First, non-slightly caking coal and four types of inferior coal were prepared. The average reflectance Ro of Vitrinit of non-slightly caking coal is 0.7%. Table 1 shows the volatile content VM of the non-slightly caking coal and the inferior coal, the total expansion coefficient TD, and the high-speed heating expansion specific volume (SV').
Hereinafter, the volatile content VM is shown by the method specified by JIS M8812, and the total expansion coefficient TD is shown by the method specified by JIS M 8801. The method for measuring the high-speed heating-expansion specific volume will be briefly described below.
高速昇温膨張比容積（ＳV’）は、ＪＩＳ Ｍ８８０１で規定される膨張性試験方法に用いる細管に、劣質炭を粒度１ｍｍ篩下１００％及び嵩密度０．８５ｇ／ｃｍ3で充填し、少なくとも４００℃に達した時点から５００℃に達するまでの平均昇温速度が３℃／分よりも高い昇温速度（ここでは、１２℃／ｍｉｎ）になるように昇温させ、その際のピストンの変位量を測定し、この変位量から膨張率を求め、この膨張率から求めた。 The high-speed heating / expansion ratio volume (SV') is such that a thin tube used in the expansion test method specified by JIS M8801 is filled with inferior carbon under a sieve having a particle size of 1 mm and a bulk density of 0.85 g / cm 3 , and at least. The temperature is raised so that the average temperature rise rate from the time when the temperature reaches 400 ° C. to reach 500 ° C. is higher than 3 ° C./min (here, 12 ° C./min), and the temperature of the piston at that time is increased. The amount of displacement was measured, the expansion rate was obtained from this amount of displacement, and the expansion rate was obtained.
表２に示す配合率及び装入嵩密度の条件において、石炭約５０ｋｇを有効寸法Ｗ２４０ｍｍ×Ｌ５４０ｍｍ×Ｈ５００ｍｍのＳＵＳ製乾留容器に充填し、石炭中部の昇温パターンが実コークス炉のそれとほぼ対応するよう、初期炉温８２０℃−最終炉温１０４０℃で昇温し１８時間乾留を行った。乾留後のコークスは窒素冷却後、表面破壊強度（ＤＩ150 6）を測定した。 Under the conditions of the compounding ratio and the charging bulk density shown in Table 2, about 50 kg of coal is filled in a SUS carbonization container having effective dimensions of W240 mm × L540 mm × H500 mm, and the temperature rise pattern in the central part of the coal almost corresponds to that of the actual coke oven. The temperature was raised at an initial furnace temperature of 820 ° C. and a final furnace temperature of 1040 ° C., and carbonization was performed for 18 hours. The surface fracture strength (DI 150 6 ) of coke after carbonization was measured after cooling with nitrogen.
図１に、非微粘結炭単味及び非微粘結炭と劣質炭からなる劣質な石炭の空隙充填度（ＳＶ×ＢＤ）に対する、表面破壊強度（ＤＩ150 6）の関係を示す。なお、膨張比容積ＳＶ［ｃｍ3／ｇ］は、通常測定時の昇温速度である３℃／分で昇温することにより測定したものである。 FIG. 1 shows the relationship of the surface fracture strength (DI 150 6 ) with respect to the void filling degree (SV × BD) of the non-slightly caking coal simple and the poor quality coal composed of the non-slightly caking coal and the inferior coal. The expansion specific volume SV [cm 3 / g] was measured by raising the temperature at 3 ° C./min, which is the rate of temperature rise during normal measurement.
図１に点線で示す関係線は、別途に複数の非微粘結炭を用いて求められた、空隙充填度（ＳＶ×ＢＤ）と表面壊強度（ＤＩ150 6）との関係であり、空隙充填度（ＳＶ×ＢＤ）の低下に伴って、表面破壊強度（ＤＩ150 6）は低下する。一方、劣質炭は、膨張性を有さないため、膨張性を有する非微粘結炭に配合すると、膨張比容積ＳＶは低下する。 The relationship line shown by the dotted line in FIG. 1 is the relationship between the void filling degree (SV × BD) and the surface fracture strength (DI 150 6 ), which was separately obtained by using a plurality of non-slightly caking coals. As the filling degree (SV × BD) decreases, the surface fracture strength (DI 150 6 ) decreases. On the other hand, inferior coal does not have expandability, so when it is mixed with non-slightly caking coal having expandability, the expansion specific volume SV decreases.
図１において、銘柄Ｂ３の劣質炭を配合した場合に、１５質量％、３０質量％と配合するに従い、つまり、空隙充填度（ＳＶ×ＢＤ）が低下するに従い、関係線から乖離する現象が確認された。また、銘柄Ｂ４の劣質炭を配合した場合は、１５質量％、３０質量％と配合するに従い、関係線から乖離する現象が確認された。すなわち、銘柄Ｂ３およびＢ４の劣質炭において、膨張性以外の強度影響因子が顕在化することを知見した。 In FIG. 1, when the inferior coal of brand B3 is blended, a phenomenon of deviation from the relational line is confirmed as the blending of 15% by mass and 30% by mass, that is, as the void filling degree (SV × BD) decreases. Was done. In addition, when the inferior coal of brand B4 was blended, a phenomenon of deviating from the relational line was confirmed as the blending was 15% by mass and 30% by mass. That is, it was found that strength influencing factors other than expansiveness became apparent in the inferior coals of brands B3 and B4.
図２に、銘柄Ｂ３の劣質炭を配合して得られたコークスのＳＥＭ写真の撮像を示す。図２（ａ）は、粒子間の状態を示す撮像であり、図２（ｂ）は、粒子表面の撮像である。図２（ａ）に示すように、劣質炭粒子を配合して得られたコークスの粒子同士は、接触しているが融着していない部分があり、図２（ｂ）に示すように、コークスの表面から剥がれ落ちた形跡がみられ、劣質炭粒子間の接着不良が示唆される。 FIG. 2 shows an SEM photograph of coke obtained by blending inferior coal of brand B3. FIG. 2A is an image showing the state between particles, and FIG. 2B is an image of the surface of the particles. As shown in FIG. 2 (a), the coke particles obtained by blending the inferior carbon particles have some parts that are in contact with each other but are not fused, and as shown in FIG. 2 (b). Evidence of peeling off from the surface of the coke suggests poor adhesion between the inferior coal particles.
そこで、本発明者らは、非微粘結炭単味および劣質炭からなる配合炭中の、劣質炭配合率及び劣質炭の性状（昇温速度１２℃／分での高速昇温膨張比容積）に対する、表面破壊強度（ＤＩ150 6）の実測値と推定値（図１の関係線）との誤差（ＤＩ150 6実計差）について調査した。図３に、劣質炭の配合率Ｘに対するＤＩ150 6実計差の関係を示す。図４に、劣質炭の高速昇温膨張比容積ＳＶ’に対するＤＩ150 6実計差の関係を示す。 Therefore, the present inventors have described the mixing ratio of the inferior coal and the properties of the inferior coal in the compounded coal composed of the non-slightly caking coal simple substance and the inferior coal (high-speed heating expansion specific volume at a heating rate of 12 ° C./min). ), The error (DI 150 6 actual difference) between the measured value of the surface fracture strength (DI 150 6 ) and the estimated value (relationship line in FIG. 1) was investigated. FIG. 3 shows the relationship between the actual difference of DI 150 6 with respect to the mixing ratio X of the inferior coal. FIG. 4 shows the relationship between the actual difference of DI 150 6 with respect to the high-speed temperature-increasing expansion ratio volume SV'of the inferior coal.
図３及び図４に示すように、配合率Ｘが高いほど、高速昇温膨張比容積ＳＶ’が低いほど、ＤＩ150 6実計差が大きくなった。そこで、本発明者らは、この知見に基づき、劣質炭の配合率Ｘと高速昇温膨張比容積ＳＶ’とを強度発現阻害要因とし、その要因と劣質炭の粒子間接着影響の相互の関係を求め、この関係を用いて劣質な石炭に基づく表面破壊強度の推定値を補正することに着想した。そして、それを実現するために劣質炭の粒子間接着影響（補正値）を以下のように式化した。 As shown in FIGS. 3 and 4, the higher the compounding ratio X and the lower the high-speed heating / expansion specific volume SV', the larger the actual difference in DI 150 6. Therefore, based on this finding, the present inventors set the compounding ratio X of the inferior coal and the high-speed heating / expansion specific volume SV'as factors for inhibiting the development of strength, and the mutual relationship between these factors and the effect of adhesion between particles of the inferior coal. And used this relationship to correct the estimated surface fracture strength based on poor coal. Then, in order to realize this, the interparticle adhesion effect (correction value) of the inferior coal was formulated as follows.
粒子間接着影響＝ａ×（Ｘ／ｂ）ｃ×（ｄ／ＳＶ’）ｅ ・・・（３）
Ｘ：劣質炭の配合率［質量％］
ＳＶ’：劣質炭の高速昇温膨張比容積ＳＶ’［ｇ／ｃｍ3］
Effect of adhesion between particles = a × (X / b) c × (d / SV') e ... (3)
X: Mixing ratio of inferior charcoal [mass%]
SV': High-speed heating and expansion ratio volume of inferior coal SV'[g / cm 3 ]
この（３）式において定数ａ、ｂ、ｃ、ｄ及びｅは、試行錯誤的に決定することができ、劣質な石炭の膨張比容積ＳＶの測定時の昇温速度が１２℃／分の条件において、ａ＝０．４、ｂ＝１５、ｃ＝３、ｄ＝１．２４、ｅ＝２０であった。 In this equation (3), the constants a, b, c, d and e can be determined by trial and error, and the temperature rising rate at the time of measuring the expansion specific volume SV of poor quality coal is 12 ° C./min. In, a = 0.4, b = 15, c = 3, d = 1.24, and e = 20.
図４中の点線は、（３）式における計算値（上側の点線：Ｘが１５質量％、下側の点線：Ｘが３０質量％）であり、劣質炭Ｂ３（ＳＶ’＝１．２４）は、配合率１５％、３０％ともＤＩ150 6実計差をよく推定できているが、劣質炭Ｂ４（ＳＶ’＝１．１８）については、いずれの配合率とも推定できないことが確認された。 The dotted line in FIG. 4 is the calculated value in the equation (3) (upper dotted line: X is 15% by mass, lower dotted line: X is 30% by mass), and is inferior coal B3 (SV'= 1.24). Although the actual difference in DI 150 6 can be estimated well for both the compounding ratios of 15% and 30%, it was confirmed that neither of the compounding ratios can be estimated for the inferior coal B4 (SV'= 1.18). ..
そこで、発明者らは劣質炭Ｂ４に関しては、強度発現阻害要因を劣質炭の粘結力指数(ＣＩ)と配合率として粒子間接着影響を（４）式のように式化した。
なお、粘結力指数ＣＩとは、石炭１ｇ（粒度０．２５mm以下）に粉コークス９ｇ（粒度０．２５〜０．３mm）を配合したものを磁性るつぼ内に入れ９００℃で７分間乾留して得られたコークスを０．４２mmの篩にかけて、その篩上に溜まった質量を百分率で表した値である。
Therefore, with respect to the inferior coal B4, the inventors formulated the interparticle adhesion effect as the equation (4) with the strength development inhibitory factor as the cohesive strength index (CI) of the inferior coal and the blending ratio.
The cohesive strength index CI is a mixture of 1 g of coal (particle size of 0.25 mm or less) and 9 g of coke breeze (particle size of 0.25 to 0.3 mm) in a magnetic crucible and carbonized at 900 ° C. for 7 minutes. The coke obtained was subjected to a 0.42 mm sieve, and the mass accumulated on the sieve was expressed as a percentage.
粒子間接着影響＝ｆ＋ｇ×ＣＩ＋ｈ×Ｘ ・・・（４）
X：劣質炭の配合率［質量％］
ＣＩ：劣質炭の粘結力指数［−］
この（４）式において、定数ｆ、ｇ、ｈは試行錯誤的に求めることができ、本実験結果からは、ｆ＝−１３．９７、ｇ＝０．３５、ｈ＝−０．３９であった。
Effect of adhesion between particles = f + g × CI + h × X ・ ・ ・ (4)
X: Inferior coal content [mass%]
CI: Cohesiveness index of inferior coal [-]
In this equation (4), the constants f, g, and h can be obtained by trial and error, and from the results of this experiment, f = -13.97, g = 0.35, and h = -0.39. It was.
次に、この粒子間接着影響を加味したコークスの表面破壊強度の推定値と、コークスの表面破壊強度の実測値との関係を調査した。
まず、粘結炭Ｘと、表１に示す非微粘結炭及び劣質炭を準備した。粘結炭のビトリニット平均反射率Ｒｏは１．２４％で、全膨張率は１０１％である。表３に示す配合率の配合炭とした。そして、配合炭を前述と同様の条件により乾留容器で乾留し、表面破壊強度（ＤＩ150 6）を測定した。
Next, the relationship between the estimated value of the surface fracture strength of coke, which takes into account the effect of adhesion between particles, and the measured value of the surface fracture strength of coke was investigated.
First, caking coal X and non-slightly caking coal and inferior coal shown in Table 1 were prepared. The Vitrinit average reflectance Ro of the caking coal is 1.24%, and the total expansion coefficient is 101%. The blended coal having the blending ratio shown in Table 3 was used. Then, the mixed coal was carbonized in a carbonization container under the same conditions as described above, and the surface fracture strength (DI 150 6 ) was measured.
また、粘結炭Ｘと、表３に示す配合率で、非微粘結炭Ａと、劣質炭Ｂ１、Ｂ３、Ｂ４のいずれかとが配合された劣質な石炭について、それぞれの膨張比容積と装入嵩密度を求め、それらの積から求められた空隙充填度と、予め求められた空隙充填度と表面破壊強度の関係とから、粘結炭と劣質な石炭それぞれに基づく表面破壊強度の推定値を得た。そして、コークスの表面破壊強度の推定値は、次のようにして求めた。 Further, for the inferior coal in which the caking coal X and the non-slightly caking coal A and any of the inferior coals B1, B3, and B4 are mixed at the blending ratio shown in Table 3, the expansion specific volume and the load of each are increased. Estimated value of surface fracture strength based on caking coal and inferior coal, respectively, from the relationship between the void filling degree obtained by determining the bulk density and the void filling degree obtained in advance and the surface breaking strength. Got Then, the estimated value of the surface fracture strength of coke was obtained as follows.
従来の推定値１として、粘結炭に基づく表面破壊強度の推定値を膨張比容積にイナートファクターを加味して求め、劣質な石炭に基づく表面破壊強度の推定値とを配合炭中の粘結炭と劣質な石炭の配合率で加重平均して求めた。
従来の推定値２として、粘結炭に基づく表面破壊強度の推定において、膨張比容積に加味するイナートファクターを、劣質炭についてはＳＶ’の関数から求め（特許文献３の手法による）、その粘結炭に基づく表面破壊強度の推定と、劣質な石炭に基づく表面破壊強度の推定値とを配合炭中の粘結炭と劣質な石炭の配合率で加重平均して求めた。
As the conventional estimated value 1, the estimated value of the surface fracture strength based on the caking coal is obtained by adding the inertia factor to the expansion ratio volume, and the estimated value of the surface fracture strength based on the inferior coal is obtained as the caking in the compound coal. It was calculated by weighted averaging with the mixing ratio of coal and inferior coal.
As the
一方、粒子間接着影響を加味した推定値１として、（３）式を用い、劣質炭の粒子間接着影響（補正値１）を求め、劣質な石炭に基づく表面破壊強度の推定値から補正値１を減じて補正推定値とし、粘結炭に基づく表面破壊強度の推定値と、劣質な石炭に基づく表面破壊強度の補正推定値とを配合炭中の粘結炭と劣質な石炭の配合率で加重平均して求めた。 On the other hand, as the estimated value 1 in consideration of the inter-particle adhesion effect, the inter-particle adhesion effect (correction value 1) of the inferior coal is obtained by using the equation (3), and the correction value is obtained from the estimated value of the surface fracture strength based on the inferior coal. 1 is subtracted to obtain the corrected estimated value, and the estimated value of the surface breaking strength based on the caking coal and the corrected estimated value of the surface breaking strength based on the inferior coal are the compounding ratio of the caking coal and the inferior coal in the compounded coal. It was calculated by weighted averaging.
また、粒子間接着影響を加味した推定値２として、劣質炭Ｂ４については（４）式を用い、劣質炭の粒子間接着影響（補正値２）を求め、劣質な石炭に基づく表面破壊強度の推定値から補正値２を減じて補正推定値とし、粘結炭に基づく表面破壊強度の推定値と、劣質な石炭に基づく表面破壊強度の補正推定値とを配合炭中の粘結炭と劣質な石炭の配合率で加重平均して求めた。
Further, as an estimated
図５に、ＤＩ150 6実測値とＤＩ150 6推定値との関係を示す。このように、従来の推定値１、従来の推定値２では、実測値との誤差が大きくなる場合があったが、（３）式により粒子間接着影響を加味した推定値１では、Ｎｏ．１〜５のいずれの配合炭においても実測値とほぼ一致した。また、（４）式により粒子間接着影響を加味した推定値２では、No.６〜７の配合炭においても推定値は実測値とほぼ一致した。
Figure 5 shows the relationship between DI 0.99 6 actual measured value and the DI 0.99 6 estimated value. As described above, in the conventional estimated value 1 and the conventional estimated
このように、粒子間接着影響を、劣質な石炭に基づく表面破壊強度の推定値からから減ずることで、コークスの表面破壊強度を正確に推定することができることを見出した。 As described above, it has been found that the surface fracture strength of coke can be accurately estimated by reducing the effect of adhesion between particles from the estimated value of the surface fracture strength based on poor quality coal.
本発明は、以上のような検討過程を経て上記（１）に記載の発明に至ったものであり、そのような本発明について、本発明の推定法の流れを説明するとともに、必要な要件や好ましい要件について順次説明する。 The present invention has reached the invention described in (1) above through the above-mentioned examination process. Regarding the present invention, the flow of the estimation method of the present invention will be explained, and necessary requirements and necessary requirements will be described. The preferred requirements will be described in sequence.
まず、表面破壊強度を推定するコークスを製造する配合炭は、次の石炭とする。
粘結炭：ビトリニット平均反射率Ｒｏが０.８％以上、全膨張率が０％超
非微粘結炭：ビトリニット平均反射率Ｒｏが０.８％未満、全膨張率が０％超
劣質炭：全膨張率が０％
なお、ビトリニット反射率Ｒｏは、ＪＩＳ Ｍ８８１６で規定される方法によって測定されるものである。
First, the compound coal for producing coke for which the surface fracture strength is estimated is the following coal.
Caking coal: Vitrinit average reflectance Ro is 0.8% or more, total expansion rate is more than 0% Non-slightly caking coal: Vitrinit average reflectance Ro is less than 0.8%, total expansion rate is more than 0% Poor coal : Total expansion rate is 0%
The Vitrinit reflectance Ro is measured by the method specified by JIS M8816.
そして、粘結炭と、非微粘結炭及び劣質炭を配合した劣質な石炭とに分けて、それぞれに関する表面破壊強度を推定する。これは、上記の性状の非微粘結炭及び劣質炭の場合、粘結炭の膨張を阻害するため、膨張比容積の加成性が成立せず、表面破壊強度の推定に影響を与えるためである。また、劣質な石炭を、非微粘結炭と劣質炭とに分けることで、非微粘結炭に基づく表面破壊強度の推定に影響する劣質炭による粒子間接着影響を補正する。 Then, the surface fracture strength of each of the caking coal and the inferior coal containing the non-slightly caking coal and the inferior coal is estimated. This is because, in the case of non-slightly caking coal and inferior coal having the above properties, the expansion of the caking coal is hindered, so that the additionability of the expansion specific volume is not established, which affects the estimation of the surface fracture strength. Is. Further, by dividing the inferior coal into non-slightly caking coal and inferior coal, the effect of interparticle adhesion by the inferior coal, which affects the estimation of the surface fracture strength based on the non-slightly caking coal, is corrected.
＜（ａ）予め求める粘結炭の空隙充填度とコークスの表面破壊強度との関係＞
複数種の粘結炭の膨張比容積を、ＪＩＳ Ｍ８８０１に規定されている測定法により測定し、複数種の粘結炭をコークス炉に装入する時の装入嵩密度を求め、上記（２）式で定義される石炭軟化時の空隙充填度を求めるとともに、乾留して表面破壊強度ＤＩ150 15を測定し、空隙充填度と粘結炭に基づく表面破壊強度との関係を予め求める。なお、粘結炭が複数銘柄の石炭を含む場合には、粘結炭の膨張比容積は、各石炭の膨張比容積を配合比率で加重平均して求めることができる。
<(A) Relationship between the void filling degree of coking coal and the surface fracture strength of coke obtained in advance>
The expansion specific volume of multiple types of caking coal was measured by the measuring method specified in JIS M8801, and the charging bulk density when charging multiple types of caking coal into a coke oven was determined. ), The void filling degree at the time of coal softening is obtained, and the surface breaking strength DI 150 15 is measured by carbonization, and the relationship between the void filling degree and the surface breaking strength based on the caking coal is obtained in advance. When the caking coal contains a plurality of brands of coal, the expansion specific volume of the caking coal can be obtained by weighted averaging the expansion specific volume of each coal by the compounding ratio.
＜（ｂ）予め求める劣質な石炭の空隙充填度とコークスの表面破壊強度との関係＞
上述の予め求める粘結炭の空隙充填度とコークスの表面破壊強度との関係の求め方と同様に、複数種の劣質な石炭の膨張比容積を測定し、複数種の劣質な石炭をコークス炉に装入する時の装入嵩密度を求め、空隙充填度を求めるとともに、乾留して表面破壊強度ＤＩ150 15を測定し、空隙充填度と劣質な石炭に基づく表面破壊強度との関係を予め求める。なお、非微粘結炭が複数銘柄の石炭を含む場合には、非微粘結炭の膨張比容積は、各石炭の膨張比容積を配合比率で加重平均して求めることができる。
<(B) Relationship between the void filling degree of inferior coal and the surface fracture strength of coke obtained in advance>
Similar to the above-mentioned method for determining the relationship between the void filling degree of caking coal and the surface breaking strength of coke, the expansion ratio volume of a plurality of types of inferior coal is measured, and a plurality of types of inferior coal are used in a coke oven. The bulk density of the charge to be charged into the coal is determined, the void filling degree is determined, and the surface breaking strength DI 150 15 is measured by carbonization, and the relationship between the void filling degree and the surface breaking strength based on poor quality coal is determined in advance. Ask. When the non-slightly caking coal contains a plurality of brands of coal, the expansion specific volume of the non-slightly caking coal can be obtained by weighted averaging the expansion specific volume of each coal by the compounding ratio.
＜（ｃ）予め求める劣質炭の強度発現阻害要因と粒子間接着影響の関係＞
［（ｃ１）劣質炭の高速昇温膨張比容積（ＳV’）の測定］
劣質炭を３℃／分よりも高い所定の昇温速度（ｖ’）で昇温して、その比容積を高速昇温膨張比容積（ＳV’）として測定する。測定した劣質炭の膨張比容積（ＳV’）と閾値（Ｔ）を比較する。
<(C) Relationship between factors that inhibit the strength development of inferior coal and the effect of adhesion between particles>
[(C1) Measurement of high-speed temperature-increasing expansion ratio volume (SV') of inferior coal]
The inferior coal is heated at a predetermined heating rate (v') higher than 3 ° C./min, and its specific volume is measured as a high-speed temperature-increasing expansion ratio volume (SV'). The measured expansion specific volume (SV') of the inferior coal and the threshold value (T) are compared.
ここで、閾値（Ｔ）は、３℃／分よりも高い所定の昇温温度（例えば１２℃／分）で測定した劣質炭の膨張比容積を用いて、上記（３）式により粒子間接着影響を加味した推定値１が、実測値とほぼ一致する領域と、推定値１と実測値が乖離する領域とを区分する値である。
この閾値（Ｔ）は、全膨張率が０％の複数の劣質炭を対象として、３℃／minよりも高い所定の昇温温度（例えば１２℃／分）で測定した劣質炭の膨張比容積を用いて、前記の推定値１と実測値とを比較することで、求めることができる。
ちなみに、昇温温度が１２℃／分であれば、閾値（Ｔ）は１．２０であることを、本発明者は実験的に確認している。
Here, the threshold value (T) is the interparticle adhesion according to the above equation (3) using the expansion specific volume of the inferior coal measured at a predetermined temperature rise temperature (for example, 12 ° C./min) higher than 3 ° C./min. The estimated value 1 in consideration of the influence is a value that separates a region that substantially matches the measured value and a region where the estimated value 1 and the measured value deviate from each other.
This threshold value (T) is the expansion specific volume of the inferior coal measured at a predetermined temperature rise temperature (for example, 12 ° C./min) higher than 3 ° C./min for a plurality of inferior coals having a total expansion rate of 0%. Can be obtained by comparing the estimated value 1 with the measured value using.
Incidentally, the present inventor has experimentally confirmed that the threshold value (T) is 1.20 when the temperature rise temperature is 12 ° C./min.
［（ｃ２）予め求める高速昇温膨張比容積と配合率とを強度発現阻害要因とする粒子間接着影響の関係］
膨張比容積（ＳＶ’）が閾値（T）よりも大きい場合、当該膨張比容積ＳＶ’と劣質な石炭中の劣質炭の配合率Ｘとを強度発現阻害要因とし、その要因と劣質炭に関する粒子間接着影響（補正値）の関係を予め求める。
[(C2) Relationship between particle-to-particle adhesion effect with preliminarily determined high-speed heating / expansion specific volume and compounding ratio as factors that inhibit strength development]
When the expansion specific volume (SV') is larger than the threshold value (T), the expansion specific volume SV'and the mixing ratio X of the inferior coal in the inferior coal are used as strength development inhibitory factors, and the factors and particles related to the inferior coal are taken as factors. The relationship of the effect of interbonding (correction value) is obtained in advance.
まず、複数種の劣質炭を用い、図３及び図４に示すような、劣質な石炭中の劣質炭の配合率Ｘ及び膨張比容積ＳＶ’に対する、表面破壊強度（ＤＩ150 6）の実測値と推定値と誤差（ＤＩ150 6実計差）の関係を求める。 First, using a plurality of types of inferior coal, the measured values of the surface fracture strength (DI 150 6 ) with respect to the compounding ratio X of the inferior coal in the inferior coal and the expansion specific volume SV'as shown in FIGS. 3 and 4. And the relationship between the estimated value and the error (DI 150 6 actual difference).
次に、劣質炭の配合率Ｘに対するＤＩ150 6実計差の関係及び劣質炭の膨張比容積ＳＶ’に対するＤＩ150 6実計差の関係において、該関係を表現できる粒子間接着影響（補正値）の式の関数形を決める。関数形は任意であり、上記（３）式の形に限定されるものではない。ここでは、上記（３）式の関数形を選択し、説明する。 Next, the relationship between DI 0.99 6 real meter difference for DI 0.99 6 expansion ratio volume SV relationships and poor quality coal real meter difference 'for blending ratio X of poor quality coal, among the particles can be expressed the relationship adhesion effect (correction value ) Determines the functional form of the expression. The functional form is arbitrary and is not limited to the form of the above equation (3). Here, the functional form of the above equation (3) is selected and described.
次に、（３）式において、定数ａ、ｂ、ｃ、ｄ及びｅを求める。
まず、図３及び図４に示すような、関係を求める試験を行った中で、最も高速昇温膨張比容積ＳＶ’の値が小さい銘柄の石炭、図３では、銘柄Ｂ３の石炭（ＳＶ’＝１．２４）について、ａ×（Ｘ／ｂ）ｃの定数を決める。試験条件の中で任意の配合率の数値を定数ｂとすると、Ｘ＝ｂのときのＤＩ150 6実計差が定数ａとなる。次に、他の配合率において、先述のａ及びｂを適用した場合、配合率の影響を説明できる乗数ｃを試行錯誤的に決定する。
Next, in the equation (3), the constants a, b, c, d and e are obtained.
First, among the tests for determining the relationship as shown in FIGS. 3 and 4, the coal of the brand having the smallest value of the high-speed heating / expansion specific volume SV', and in FIG. 3, the coal of the brand B3 (SV'). = 1.24), determine the constant of a × (X / b) c. Assuming that the numerical value of an arbitrary compounding ratio is a constant b in the test conditions, the DI 150 6 actual total difference when X = b is a constant a. Next, when the above-mentioned a and b are applied to other compounding ratios, a multiplier c that can explain the influence of the compounding ratio is determined by trial and error.
次に、劣質炭の配合率Ｘを固定した場合に、図４の変化を説明できるｄ及びｅを試行錯誤的に決定する。これらは、劣質炭の配合率Ｘと高速昇温膨張比容積ＳＶ’のＤＩ150 6実計差に及ぼす影響感度がひとつの乗数で説明できないために行うのであり、式中の定数ａ、ｂ、ｃ、ｄ、及びｅは、図３及び図４に示す関係を求める試験の条件により異なる。 Next, when the blending ratio X of the inferior coal is fixed, d and e that can explain the change in FIG. 4 are determined by trial and error. This is done because the sensitivity of the influence of the mixing ratio X of the inferior coal and the high-speed heating / expansion specific volume SV'on the DI 150 6 actual measurement difference cannot be explained by a single multiplier. c, d, and e differ depending on the test conditions for determining the relationship shown in FIGS. 3 and 4.
図３の例では、劣質な石炭の膨張比容積ＳＶの測定時の昇温速度は１２℃／ｍｉｎとし、その条件においては、ａ＝０．４、ｂ＝１５、ｃ＝３、ｄ＝１．２４、ｅ＝２０となった。 In the example of FIG. 3, the heating rate at the time of measuring the expansion specific volume SV of inferior coal is 12 ° C./min, and under that condition, a = 0.4, b = 15, c = 3, d = 1. .24, e = 20.
［（ｃ３）予め求める石炭粘結力指数と配合率とを強度発現阻害要因とする粒子間接着影響の関係］
膨張比容積(ＳＶ’)が閾値（Ｔ）以下の場合、さらに劣質炭の粘結力指数ＣＩを測定しておき、該粘結力指数ＣＩと劣質な石炭中の劣質炭の配合率Ｘとを強度発現阻害要因とし、その要因と劣質炭に関する粒子間接着影響（補正値）の関係を予め求める。
[(C3) Relationship between the coal cohesive strength index and the blending ratio obtained in advance and the effect of adhesion between particles with the strength development inhibitory factor]
When the expansion specific volume (SV') is equal to or less than the threshold value (T), the cohesive strength index CI of the inferior coal is further measured, and the cohesive strength index CI and the blending ratio X of the inferior coal in the inferior coal are combined with each other. Is a factor that inhibits the development of strength, and the relationship between that factor and the interparticle adhesion effect (correction value) for inferior coal is determined in advance.
配合炭中の膨張比容積(ＳＶ’)が閾値（Ｔ）以下の劣質炭について、上記（ｃ２）と同様に、配合率Ｘ及び粘結力指数ＣＩに対する表面破壊強度（ＤＩ150 6）の実測値と推定値と誤差（ＤＩ150 6実計差）の関係を求め、次に、劣質炭の配合率Ｘに対するＤＩ150 6実計差の関係及び劣質炭の粘結力指数ＣＩに対するＤＩ150 6実計差の関係において、該関係を表現できる粒子間接着影響（補正値）の式の関数形を決める。そして、その関数を用いて補正値を求める。
用いる関数形は任意であり、前記（４）式の形に限定されるものではないが、（４）式を用いる場合は、定数ｆ、ｇ、ｈは試行錯誤的に求めることができ、本実験結果からはｆ＝−１３．９７、ｇ＝０．３５、ｈ＝−０．３９であった。
For inferior coal having an expansion specific volume (SV') of less than the threshold value (T) in the blended coal, the actual measurement of the surface fracture strength (DI 150 6) with respect to the blending ratio X and the cohesive strength index CI is the same as in the above (c2). The relationship between the value, the estimated value, and the error (DI 150 6 actual difference) was obtained, and then the relationship between the actual difference and the DI 150 6 actual difference with respect to the mixing ratio X of the inferior coal and the DI 150 6 with respect to the cohesive strength index CI of the inferior coal. In relation to the actual difference, the functional form of the equation of the interparticle adhesion effect (correction value) that can express the relationship is determined. Then, the correction value is obtained using the function.
The functional form used is arbitrary and is not limited to the form of the above equation (4), but when the equation (4) is used, the constants f, g, and h can be obtained by trial and error. From the experimental results, f = -13.97, g = 0.35, and h = -0.39.
上記のように、実際に使用を想定している劣質炭の性状範囲において、上記関係を求める試験を実施し、粒子間接着影響を式化しておけば、使用に際して劣質炭の膨張比容積ＳＶ’を（３）式を導出する際の条件にて測定し、膨張比容積SV’の閾値Ｔに応じて（３）式あるいは（４）式を選択し用いるのみで、粒子間接着影響を評価することができる。 As described above, if the test for obtaining the above relationship is carried out in the property range of the inferior coal that is actually supposed to be used and the effect of adhesion between particles is formulated, the expansion specific volume SV'of the inferior coal will be used. (3) is measured under the conditions for deriving the equation (3), and the effect of adhesion between particles is evaluated only by selecting and using the equation (3) or the equation (4) according to the threshold value T of the expansion specific volume SV'. be able to.
＜（ｄ）用いる配合炭中の粘結炭に基づく表面破壊強度の推定＞
用いる配合炭中の粘結炭に基づく表面破壊強度を、その膨張比容積と装入嵩密度との積から空隙充填度を求め、該空隙充填度と（ａ）の関係から推定する。なお、粘結炭が複数銘柄の石炭を含む場合には、粘結炭の膨張比容積は、各石炭の膨張比容積を配合比率で加重平均して求めることができる。
<(D) Estimating surface fracture strength based on caking coal in the compound coal used>
The surface fracture strength based on the caking coal in the compound coal to be used is estimated from the relationship between the void filling degree and (a) by obtaining the void filling degree from the product of the expansion specific volume and the charging bulk density. When the caking coal contains a plurality of brands of coal, the expansion specific volume of the caking coal can be obtained by weighted averaging the expansion specific volume of each coal by the compounding ratio.
また、非微粘結炭及び劣質炭は、粘結炭よりも再固化温度が低いものが多く、粘結炭が軟化溶融しているときには、非微粘結炭及び劣質炭は既に再固化しており、粘結炭の膨張が抑制される。そこで、特許文献２に開示されるように、非微粘結炭及び劣質炭の配合率に対して、粘結炭の膨張抑制効果をイナートファクターＩＦとして式化しておき、粘結炭の膨張比容積にイナートファクターＩＦを掛けて、空隙充填度を求める際の膨張比容積としてもよい。これにより、粘結炭に基づく表面破壊強度の推定値の正確性を向上させることができるため好ましい。
In addition, many non-slightly caking coals and inferior coals have a lower resolidification temperature than caking coals, and when the caking coals are softened and melted, the non-slightly caking coals and inferior coals are already resolidified. The expansion of the caking coal is suppressed. Therefore, as disclosed in
＜（ｅ）用いる配合炭中の劣質な石炭に基づく表面破壊強度の推定＞
劣質な石炭に基づく表面破壊強度を、その膨張比容積と装入嵩密度との積から空隙充填度を求め、該空隙充填度と（ｂ）の関係から推定する。なお、非微粘結炭が複数銘柄の石炭を含む場合には、非微粘結炭の膨張比容積は、各石炭の膨張比容積を配合比率で加重平均して求めることができる。
<(E) Estimating surface fracture strength based on inferior coal in the compound coal used>
The surface fracture strength based on poor quality coal is estimated from the relationship between the void filling degree and (b) by obtaining the void filling degree from the product of the expansion specific volume and the charged bulk density. When the non-slightly caking coal contains a plurality of brands of coal, the expansion specific volume of the non-slightly caking coal can be obtained by weighted averaging the expansion specific volume of each coal by the compounding ratio.
＜（ｆ）用いる配合炭中の劣質炭について補正値の導出＞
（f1）用いる劣質炭について、３℃／分よりも高い所定の昇温速度（v’）で測定した高速昇温膨張比容積（SV’）が閾値（Ｔ）よりも大きい場合、当該膨張比容積ＳV’と劣質な石炭中の当該劣質炭の配合率を求める。そして、膨張比容積及び劣質炭の配合率と、前記（ｃ２）の関係とから、粒子間接着影響（補正値１）を求める。なお、３℃／分よりも高い昇温速度としては、６℃／分が好ましく、１２℃／分がより好ましい。
<(F) Derivation of correction values for inferior coal in the compound coal used>
(F1) When the high-speed heating expansion specific volume (SV') measured at a predetermined temperature rising rate (v') higher than 3 ° C./min is larger than the threshold value (T) for the inferior coal used, the expansion ratio is concerned. The volume SV'and the mixing ratio of the inferior coal in the inferior coal are obtained. Then, the effect of adhesion between particles (correction value 1) is obtained from the relationship between the expansion specific volume and the blending ratio of the inferior coal and the above (c2). The rate of temperature rise higher than 3 ° C./min is preferably 6 ° C./min, more preferably 12 ° C./min.
また、１２℃／分でも劣質炭間の高速昇温膨張比容積の差が大きくない場合は、さらに高速で昇温してもよく、例えば、５０℃／分、さらには１００℃／分が例示できる。
この様に、大きな昇温速度として、例えば、１００℃／分で高速昇温膨張比容積を測定する場合は、特開２０１４−０１９８１４号公報に開示されている方法が推奨される。すなわち、劣質炭を細管に入れ、この細管にピストンを挿入し、少なくとも４００℃に達した時点から５００℃に達するまでの間の平均昇温速度が１００℃／分になるように、５５０℃に保持した加熱炉に細管を装入し、その際のピストンの変位量を測定し、この変位量から膨張率を求め、この膨張率から求める方法が、推奨される。
Further, if the difference in high-speed heating / expansion ratio volume between the inferior coals is not large even at 12 ° C./min, the temperature may be raised at a higher speed, for example, 50 ° C./min and further 100 ° C./min. it can.
As described above, when measuring the high-speed heating / expansion ratio volume at 100 ° C./min, for example, as a large heating rate, the method disclosed in Japanese Patent Application Laid-Open No. 2014-019814 is recommended. That is, inferior charcoal is put into a thin tube, a piston is inserted into the thin tube, and the temperature is set to 550 ° C. so that the average heating rate from at least 400 ° C. to 500 ° C. is 100 ° C./min. A method is recommended in which a thin tube is charged into the holding heating furnace, the displacement amount of the piston at that time is measured, the expansion rate is obtained from this displacement amount, and the expansion rate is obtained from this expansion rate.
なお、３℃／分よりも高い所定の昇温速度（v’）で測定した高速昇温膨張比容積（ＳＶ’）が閾値（Ｔ）よりも大きい劣質炭として、高速昇温膨張比容積（ＳＶ’）の上限は特に限定されない。但し、例えば、１２℃／分で測定した場合に１．３５よりも大きい劣質炭は、従来推定値との差があまり大きくないことから、高速昇温膨張比容積（ＳＶ’）の１２℃／分での好ましい上限値としては１．３５が例示される。 The high-speed heating-expansion specific volume (SV') measured at a predetermined heating rate (v') higher than 3 ° C./min is a poor quality coal having a larger high-speed heating-expansion specific volume (SV') than the threshold value (T). The upper limit of SV') is not particularly limited. However, for example, inferior coal larger than 1.35 when measured at 12 ° C./min has a small difference from the conventional estimated value, and therefore has a high-speed heating / expansion specific volume (SV') of 12 ° C./. 1.35 is exemplified as a preferable upper limit value in minutes.
（f2）一方、用いる劣質炭について、３℃／分よりも高い所定の昇温速度（v’）で測定した高速昇温膨張比容積（SV’）が閾値（Ｔ）以下の場合、当該劣質炭について、粘結力指数（ＣＩ）を求め、また、劣質な石炭中の劣質炭の配合率を求める。そして、粘結力指数（ＣＩ）及び劣質炭の配合率と、前記（ｃ３）の関係とから、粒子間接着影響（補正値２）を求める。 (F2) On the other hand, when the high-speed heating / expansion specific volume (SV') measured at a predetermined temperature rising rate (v') higher than 3 ° C./min is equal to or less than the threshold value (T), the poor quality coal is used. For charcoal, the cohesiveness index (CI) is determined, and the mixing ratio of inferior coal in inferior coal is determined. Then, the effect of adhesion between particles (correction value 2) is obtained from the relationship between the cohesive strength index (CI) and the blending ratio of the inferior coal and the above (c3).
＜（ｇ）劣質な石炭に基づく表面破壊強度の補正推定値の導出＞
（ｅ）で求めた劣質な石炭に基づく表面破壊強度の推定値から、（ｆ）で求めた補正値１または補正値２を減じて、劣質な石炭に基づく表面破壊強度の補正推定値を求める。
<(G) Derivation of corrected estimated value of surface fracture strength based on poor quality coal>
The correction value 1 or the
＜（ｈ）コークス表面破壊強度の推定＞
（ｄ）で求めた粘結炭に基づく表面破壊強度の推定値と、（ｇ）で求めた劣質な石炭に基づく表面破壊強度の補正推定値とを、用いる配合炭中の粘結炭と劣質な石炭の配合率で加重平均して、コークス表面破壊強度を推定する。
なお、求められたコークス表面破壊強度と、例えば、特許文献２に記載された方法に従い求められる体積破壊強度とから、ドラム強度ＤＩ150 15を推定してもよい。
<(H) Estimation of coke surface fracture strength>
The estimated value of the surface fracture strength based on the caking coal obtained in (d) and the corrected estimated value of the surface fracture strength based on the inferior coal obtained in (g) are used as the caking coal and inferior quality in the compound coal to be used. The coke surface fracture strength is estimated by weighted averaging with the blending ratio of coal.
The drum strength DI 150 15 may be estimated from the obtained coke surface breaking strength and, for example, the volume breaking strength obtained according to the method described in
（粘結炭と劣質な石炭との配合比）
粘結炭と劣質な石炭との配合比は、特に限定されるものでないが、粘結炭と劣質な石炭に分けずに表面破壊強度を推定していた場合、配合炭中の劣質な石炭の配合率が３０質量％以上の場合、推定値の正確性が低かったため、本発明の推定法において、配合炭中の劣質な石炭の配合率を３０質量％以上としてもよい。より好ましくは配合率を４５質量％以上としてもよい。
(Mixing ratio of caking coal and inferior coal)
The compounding ratio of the caking coal and the inferior coal is not particularly limited, but when the surface fracture strength is estimated without dividing the caking coal and the inferior coal, the inferior coal in the compounded coal When the blending ratio is 30% by mass or more, the accuracy of the estimated value is low. Therefore, in the estimation method of the present invention, the blending ratio of inferior coal in the blended coal may be 30% by mass or more. More preferably, the blending ratio may be 45% by mass or more.
（劣質な石炭中の劣質炭の配合率）
劣質な石炭中の劣質炭の配合率は、特に限定されるものでないが、劣質な石炭中の劣質炭の配合率が１０質量％以上の場合、劣質な石炭の表面強度の推定値の正確性が低くなることがあるため、本発明の推定法において、劣質な石炭中の劣質炭の配合率を１０質量％以上としてもよい。
(Mixing ratio of inferior coal in inferior coal)
The mixing ratio of the inferior coal in the inferior coal is not particularly limited, but when the mixing ratio of the inferior coal in the inferior coal is 10% by mass or more, the accuracy of the estimated value of the surface strength of the inferior coal In the estimation method of the present invention, the blending ratio of the inferior coal in the inferior coal may be 10% by mass or more.
次に、本発明の実施例について説明するが、実施例での条件は、本発明の実施可能性及び効果を確認するために採用した一条件例であり、本発明は、この一条件例に限定されるものではない。本発明は、本発明の要旨を逸脱せず、本発明の目的を達成する限りにおいて、種々の条件を採用し得るものである。 Next, an example of the present invention will be described. The conditions in the examples are one condition example adopted for confirming the feasibility and effect of the present invention, and the present invention is described in this one condition example. It is not limited. The present invention can adopt various conditions as long as the gist of the present invention is not deviated and the object of the present invention is achieved.
まず、粘結炭、非微粘結炭及び４種の劣質炭を準備した。表４に、粘結炭、非微粘結炭及び劣質炭の揮発分量ＶＭ、全膨張率ＴＤ、及び、高速昇温膨張比容積ＳＶ’を示す（ここで、高速昇温膨張比容積ＳＶ’は１２℃／分の昇温速度で測定した。また、膨張比容積ＳＶ´の閾値（Ｔ）は１．２０である。）。粘結炭Ｙのビトリニット平均反射率Ｒｏは１．２４％で、非微粘結炭Ｃのビトリニット平均反射率Ｒｏは０．７０％である。 First, caking coal, non-slightly caking coal and four kinds of inferior coal were prepared. Table 4 shows the volatile content VM of the caking coal, the non-slightly caking coal and the inferior coal, the total expansion ratio TD, and the high-speed heating expansion expansion specific volume SV'(here, the high-speed heating expansion expansion specific volume SV'). Was measured at a heating rate of 12 ° C./min. The threshold value (T) of the expansion specific volume SV'is 1.20). The average reflectance Ro of the vitrinit of the caking coal Y is 1.24%, and the average reflectance Ro of the vitrinit of the non-slightly caking coal C is 0.70%.
表５に示す配合率において、石炭約９０ｋｇを有効寸法Ｗ４２０×Ｌ６１０×Ｈ４００ｍｍの焼成缶に充填し、０．８５ｔ／ｍ3（実機０．８０ｔ／ｍ3相当）の嵩密度で装入した後、試験コークス炉にて乾留した。そして、乾留後のコークスについて、表面破壊強度（ＤＩ150 6）を測定した。 In the blending ratio shown in Table 5, after about 90 kg of coal was filled in a baking can with effective dimensions W420 × L610 × H400 mm and charged at a bulk density of 0.85 t / m 3 (equivalent to 0.80 t / m 3 of the actual machine). , Distilled in a test coke oven. Then, the surface fracture strength (DI 150 6 ) of the coke after carbonization was measured.
予め粘結炭の空隙充填度とコークスの表面破壊強度との関係及び劣質な石炭の空隙充填度とコークスの表面破壊強度との関係を求めた。そして、粘結炭Ｙと、表５に示す配合率で、非微粘結炭Ｃと、劣質炭Ｄ１、Ｄ２、Ｄ３、Ｄ４、Ｄ５とが配合された劣質な石炭の膨張比容積と装入嵩密度を求め、それから求められた空隙充填度と、前記関係から、粘結炭と劣質な石炭それぞれに基づく表面破壊強度の推定値を得た。そして、コークスの表面破壊強度の推定値を次のように求めた。 The relationship between the void filling degree of the caking coal and the surface fracture strength of coke and the relationship between the void filling degree of poor quality coal and the surface fracture strength of coke were obtained in advance. Then, the expansion ratio volume and charge of the caking coal Y, the non-slightly caking coal C, and the inferior coals D1, D2, D3, D4, and D5 in the blending ratio shown in Table 5 are blended. The bulk density was obtained, and the estimated value of the surface fracture strength based on the caking coal and the inferior coal was obtained from the obtained void filling degree and the above relationship. Then, the estimated value of the surface fracture strength of coke was obtained as follows.
比較例では、粘結炭に基づく表面破壊強度を、劣質な石炭による粘結炭の膨張抑制効果を考慮して、すなわちイナートファクターＩＦを粘結炭の膨張比容積に掛けたものから推定し、この粘結炭に基づく表面破壊強度の推定値と、劣質な石炭に基づく表面破壊強度の推定値とを、配合炭中の粘結炭と劣質な石炭の配合率で加重平均して、コークスの表面破壊強度の推定値を求めた。図６に、比較例のＤＩ150 6実測値とＤＩ150 6推定値との関係を示す。 In the comparative example, the surface breaking strength based on the caking coal is estimated by considering the expansion suppressing effect of the caking coal by the inferior coal, that is, the inert factor IF is multiplied by the expansion ratio volume of the caking coal. The estimated value of the surface breaking strength based on this caking coal and the estimated value of the surface breaking strength based on inferior coal are weighted and averaged by the mixing ratio of the caking coal and the inferior coal in the blended coal, and the coke is used. An estimated value of surface fracture strength was obtained. FIG. 6 shows the relationship between the DI 150 6 measured value and the DI 150 6 estimated value in the comparative example.
発明例では、１２℃／分で測定した膨張比容積ＳＶ’が１．２０超である劣質炭Ｄ１〜Ｄ４を配合したケースNo.１〜No.７については上記（３）式を、１２℃／分で測定したＳＶ’が１．２０以下である劣質炭Ｄ５を配合したケースNo.８については（４）式を用い、劣質炭の粒子間接着影響（補正値）を求め、劣質な石炭に基づく表面破壊強度の推定値から補正値を減じて補正推定値とし、劣質な石炭による粘結炭の膨張抑制効果を考慮、すなわちイナートファクターＩＦを粘結炭の膨張比容積に掛けたものから求めた粘結炭の表面破壊強度とを、劣質な石炭に基づく表面破壊強度の補正推定値とを配合炭中の粘結炭と劣質な石炭の配合率で加重平均して、コークスの表面破壊強度の推定値を求めた。図７に、発明例のＤＩ150 6実測値とＤＩ150 6推定値との関係を示す。 In the example of the invention, for the cases No. 1 to No. 7 containing the inferior coals D1 to D4 having the expansion ratio volume SV'measured at 12 ° C./min exceeding 1.20, the above formula (3) was used at 12 ° C. For case No. 8 containing the inferior coal D5 with an SV'measured at / min of 1.20 or less, the interparticle adhesion effect (correction value) of the inferior coal was obtained using equation (4), and the inferior coal was obtained. The correction value is subtracted from the estimated value of the surface fracture strength based on the above to obtain the correction estimation value, and the expansion suppression effect of the caking coal due to inferior coal is taken into consideration, that is, the inert factor IF is multiplied by the expansion ratio volume of the caking coal. The surface breaking strength of the obtained caking coal and the corrected estimated value of the surface breaking strength based on the inferior coal are weighted and averaged by the mixing ratio of the caking coal and the inferior coal in the compounded coal, and the surface fracture of the coke. An estimated value of intensity was obtained. FIG. 7 shows the relationship between the measured value of DI 150 6 and the estimated value of DI 150 6 of the invention example.
図６に示すように、比較例の表面破壊強度のＤＩ150 6推定値は、ＤＩ150 6実測値と大きく乖離している。それに対して、図７に示すように、発明例の表面破壊強度のＤＩ150 6推定値は、粒子間接着影響項を反映しているため、ＤＩ150 6実測値と非常に良く一致しており、劣質炭配合時の表面破壊強度急落に対する推定値の正確性が大幅に向上した。 As shown in FIG. 6, the DI 150 6 estimated value of the surface fracture strength of the comparative example greatly deviates from the DI 150 6 measured value. On the other hand, as shown in FIG. 7, the DI 150 6 estimated value of the surface fracture strength of the invention example reflects the interparticle adhesion influence term, and therefore is very in agreement with the DI 150 6 measured value. , The accuracy of the estimated value for the sudden drop in surface fracture strength when compounding inferior coal has been greatly improved.
本発明によれば、劣質炭に関する粒子間接着影響を補正値として、劣質な石炭に基づく表面破壊強度の推定値から減じるので、劣質炭を配合した配合炭を用いて製造するコークスの表面破壊強度を正確に推定することができる。よって、本発明は、産業上の利用可能性が高いものである。 According to the present invention, the effect of interparticle adhesion on the inferior coal is used as a correction value and is subtracted from the estimated value of the surface fracture strength based on the inferior coal. Can be estimated accurately. Therefore, the present invention has high industrial applicability.
Claims (2)
前記配合炭は、ビトリニット平均反射率Ｒｏが０.８％以上、ＪＩＳ Ｍ ８８０１で規定される方法によって測定される全膨張率が０％超の粘結炭、及び、劣質な石炭として、ビトリニット平均反射率Ｒｏが０.８％未満で当該全膨張率が０％超の非微粘結炭と当該全膨張率が０％の劣質炭からなり、
（ａ）予め、複数の粘結炭の膨張比容積と装入嵩密度との積から求められる空隙充填度と、得られるコークスの表面破壊強度との関係を求め、
（ｂ）予め、複数の非微粘結炭と劣質炭とを配合した劣質な石炭の膨張比容積と装入嵩密度との積から求められる空隙充填度と、得られるコークスの表面破壊強度との関係を求め、
（ｃ）予め、劣質炭の強度発現阻害要因と粒子間接着影響の補正値との関係を以下のようにして求め、
（c1）劣質炭を３℃／分よりも高い所定の昇温速度で昇温したときの膨張比容積を高速昇温膨張比容積ＳV’として測定し、
（c2）測定した劣質炭の膨張比容積ＳV’が閾値Ｔよりも大きい場合、予め、当該膨張比容積ＳV’と劣質な石炭中の当該劣質炭の配合率とを強度発現阻害要因とし、その要因に基づく劣質炭に関する粒子間接着影響を補正値１とする相互の関係を求め、
（c3）測定した劣質炭の膨張比容積ＳV’が前記閾値Ｔ以下の場合、さらに当該劣質炭の粘結力指数ＣＩを測定し、予め、測定した粘結力指数ＣＩと劣質な石炭中の当該劣質炭の配合率とを強度発現阻害要因とし、その要因に基づく劣質炭に関する粒子間接着影響を補正値２とする相互の関係を求め、
コークスの表面破壊強度の推定にあたり、
（ｄ）用いる配合炭中の粘結炭の空隙充填度を同様に求め、前記（ａ）の関係から当該粘結炭に基づく表面破壊強度の推定値を求め、
（ｅ）用いる配合炭中の劣質な石炭の空隙充填度を同様に求め、前記（ｂ）の関係から当該劣質な石炭に基づく表面破壊強度の推定値を求め、
（ｆ）用いる配合炭中の劣質炭の膨張比容積ＳV’を求め、前記閾値Ｔとの関係に応じて、以下のようにして補正値を求め、
（f1）用いる配合炭中の劣質炭の膨張比容積ＳV’が前記閾値Ｔよりも大きい場合は、当該膨張比容積ＳV’と劣質な石炭中の当該劣質炭の配合率を求め、前記（c2）の関係から補正値１を求め、
（f2）用いる配合炭中の劣質炭の膨張比容積ＳV’が前記閾値Ｔ以下の場合は、当該劣質炭の粘結力指数ＣＩと劣質な石炭中の当該劣質炭の配合率を求め、前記（c3）の関係から補正値２を求め、
（ｇ）前記（ｅ）で求めた劣質な石炭に基づく表面破壊強度の推定値から、劣質炭の膨張比容積ＳV’に応じて、前記（f1）または（f2）で求めた補正値１または補正値２を減じて劣質な石炭に基づく表面破壊強度の補正推定値を求め、
（ｈ）前記（ｄ）で求めた粘結炭に基づく表面破壊強度の推定値と、前記（ｇ）で求めた劣質な石炭に基づく表面破壊強度の補正推定値とを、用いる配合炭中の粘結炭と劣質な石炭の配合率で加重平均する
ことを特徴とするコークス表面破壊強度の推定方法。 In the method for estimating the surface fracture strength of coke produced using a blended coal containing inferior charcoal,
The compound coal has a Vitrinit average reflectance Ro of 0.8% or more, a caking coal having a total expansion coefficient of more than 0% measured by the method specified by JIS M 8801, and a Vitrinit average as a poor quality coal. It consists of non-slightly caking coal with a reflectance Ro of less than 0.8% and a total expansion rate of more than 0% and inferior coal with a total expansion rate of 0%.
(A) The relationship between the void filling degree obtained from the product of the expansion specific volume of a plurality of caking coals and the charged bulk density and the surface fracture strength of the obtained coke was obtained in advance.
(B) The void filling degree obtained from the product of the expansion specific volume and the charged bulk density of the inferior coal in which a plurality of non-slightly caking coals and the inferior coal are mixed in advance, and the surface fracture strength of the obtained coke. Seeking a relationship,
(C) The relationship between the factor that inhibits the strength development of inferior coal and the correction value of the effect of adhesion between particles is obtained in advance as follows.
(C1) The expansion specific volume when the inferior coal is heated at a predetermined temperature rising rate higher than 3 ° C./min is measured as the high-speed heating expansion specific volume SV'.
(C2) When the measured expansion specific volume SV'of the inferior coal is larger than the threshold value T, the expansion specific volume SV'and the mixing ratio of the inferior coal in the inferior coal are set as strength development inhibitory factors in advance. Find the mutual relationship with the correction value 1 for the interparticle adhesion effect on the inferior coal based on the factor.
(C3) When the measured expansion specific volume SV'of the inferior coal is equal to or less than the threshold value T, the cohesive force index CI of the inferior coal is further measured, and the cohesive force index CI measured in advance and the inferior coal The mutual relationship was obtained by using the compounding ratio of the inferior coal as a factor that inhibits the development of strength and the effect of interparticle adhesion on the inferior coal based on that factor as the correction value 2.
In estimating the surface fracture strength of coke,
(D) The void filling degree of the caking coal in the compound coal to be used was obtained in the same manner, and the estimated value of the surface fracture strength based on the caking coal was obtained from the relationship of (a) above.
(E) The void filling degree of the inferior coal in the compound coal to be used was obtained in the same manner, and the estimated value of the surface fracture strength based on the inferior coal was obtained from the relation of the above (b).
(F) The expansion specific volume SV'of the inferior coal in the compound coal to be used was obtained, and the correction value was obtained as follows according to the relationship with the threshold value T.
(F1) When the expansion specific volume SV'of the inferior coal in the blended coal to be used is larger than the threshold value T, the blending ratio of the expansion specific volume SV'and the inferior coal in the inferior coal is obtained, and the above (c2) ), Find the correction value 1 and
(F2) When the expansion specific volume SV'of the inferior coal in the compound coal to be used is equal to or less than the threshold value T , the cohesive strength index CI of the inferior coal and the compounding ratio of the inferior coal in the inferior coal are obtained. Obtain the correction value 2 from the relationship of (c3),
(G) From the estimated value of surface fracture strength based on the inferior coal obtained in the above (e), the correction value 1 or the correction value 1 obtained in the above (f1) or (f2) according to the expansion specific volume SV'of the inferior coal. Subtract the correction value 2 to obtain the correction estimate of the surface fracture strength based on inferior coal.
(H) The estimated value of the surface fracture strength based on the caking coal obtained in the above (d) and the corrected estimated value of the surface fracture strength based on the inferior coal obtained in the above (g) are used in the compound coal to be used. A method for estimating the surface fracture strength of coke, which is characterized by weighted averaging based on the blending ratio of caking coal and inferior coal.
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