Abstract Three Miocene-age coal seams - a lower seam (kM2, subbituminous), a middle seam (kM3, subbituminous), and an upper seam (kP1, lignite) - in the Kinik coalfield, located in the southwesternmost part of the Soma Basin in western Turkey, and factors controlling mesoporosity and microporosity characteristics, were investigated using low-pressure N2 and CO2 adsorption techniques, respectively. In addition, this study is also aimed to compare controlling factors on meso- and microporosity characteristics of Soma Basin and Late Carboniferous Zonguldak, and Late Miocene-Pliocene Dombayova Basins. It is found that distinct differences with regard to meso- and microporosity exist among the three seams (kM2, kM3 and kP1) investigated in the Kinik coalfield. Specifically, samples from kP1 have greater mesopore surface areas and volumes than those from kM3. In addition, samples from the upper part of kM2 have significantly lower mesopore surface area and volume than from the lower part of this seam and from kM3 and kP1. Samples from the lower part of kM2 have higher meso- and micropore surface area and volume values than kM3 and kP1 samples. The increase in mesopore surface area and volume, along with the increase in ash yield toward the lower part of kM2, suggests that mesoporosity characteristics in this seam appear to be controlled mainly by mineral matter content. The results of this study show that meso- and micropore surface area and volume of Miocene subbituminous coal (kM2) in Kinik and Eynez coalfields of the Soma Basin have higher values than lignite from the Dombayova Basin and bituminous coal from the Zonguldak Basin. The differences in mesopore characteristics between the Soma and the Zonguldak Basins could be related to differences in rank. In addition, the mesoporosity of coal seams in the Dombayova Basin is more similar to seams in the Zonguldak Basin. These conflicting data suggest that rank might not be a controlling factor on the meso- and micropore characteristics of the basins investigated in this paper. Nevertheless, the common presence of structured huminite macerals in the Soma Basin seems to have caused relatively higher microporosity surface area and volume values, whereas the common presence of illite, particularly in the lower parts of kM2, resulted in higher values of mesopore surface area and volume in the Soma Basin samples. Consequently, maceral and mineralogical compositions of the studied Turkish coals seem to exert major controls on meso- and micropore characteristics.

中文翻译：

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Kınık 煤田（土耳其西部索马盆地）中新世褐煤和亚烟煤的中孔和微孔特征

摘要 位于索马盆地西南部的 Kinik 煤田中的三个中新世煤层 - 下层煤层（kM2，亚烟煤）、中层煤层（kM3，亚烟煤）和上层煤层（kP1，褐煤）在土耳其西部，分别使用低压 N2 和 CO2 吸附技术研究了控制介孔和微孔特征的因素。此外，本研究还旨在比较索马盆地与晚石炭世宗古尔达克盆地和晚中新世-上新世东巴约瓦盆地中微孔特征的控制因素。发现在 Kinik 煤田调查的三个煤层（kM2、kM3 和 kP1）之间存在明显的中孔和微孔性差异。具体来说，来自 kP1 的样品比来自 kM3 的样品具有更大的中孔表面积和体积。此外，与来自该接缝下部以及来自 kM3 和 kP1 的样品相比，来自 kM2 上部的样品具有显着更低的中孔表面积和体积。来自 kM2 下部的样品比 kM3 和 kP1 样品具有更高的中孔和微孔表面积和体积值。中孔表面积和体积的增加，以及向 kM2 较低部分的灰分产量的增加，表明该煤层中的中孔特征似乎主要受矿物质含量控制。本研究结果表明，索马盆地 Kinik 和 Eynez 煤田中新世亚烟煤的中孔和微孔表面积和体积 (kM2) 的值高于 Dombayova 盆地的褐煤和 Zonguldak 盆地的烟煤。Soma 盆地和 Zonguldak 盆地之间介孔特征的差异可能与等级差异有关。此外，Dombayova 盆地煤层的介孔性与 Zonguldak 盆地的煤层更相似。这些相互矛盾的数据表明，等级可能不是本文所研究盆地的中孔和微孔特征的控制因素。尽管如此，在索马盆地普遍存在的结构化腐殖质微孔似乎导致了相对较高的微孔表面积和体积值，而伊利石的普遍存在，特别是在 kM2 的较低部分，导致索马盆地样品中孔表面积和体积的值更高。因此，所研究的土耳其煤的矿物成分和矿物成分似乎对中孔和微孔特征起到了主要控制作用。