報告書番号

M11016

タイトル（和文）

亜瀝青炭の粉砕特性評価

タイトル（英文）

Pulverizing characteristics of sub-bituminous coal

概要 （図表や脚注は「報告書全文」に掲載しております）

ローラミルを用いて、瀝青炭と亜瀝青炭の粉砕性について、動力原単位と微粉炭粒径で算出されるBondの粉砕仕事指数を用いて評価した。低水分の亜瀝青炭を粉砕した際のローラミルの粉砕仕事指数は、瀝青炭と同様にHGIを用いて粉砕性を評価できるが、付着水分の多い亜瀝青炭を粉砕した際は、同じHGIの石炭に比べて、粉砕仕事指数が大きくなった。これは、付着水分が多いとローラが滑りやすくなり、粉砕し難くなるためと考えられる。亜瀝青炭は、HGIに加えて、付着水分を考慮することで、粉砕仕事指数を推算できることを明らかにした。亜瀝青炭混炭時の粉砕仕事指数は、各炭種の単味粉砕時の粉砕仕事指数を推算し、混炭率に応じて加重平均することで推算可能になることがわかった。

概要 （英文）

In this investigation, we evaluated the pulverizing characteristics of both bituminous and sub-bituminous coals using a roller mill in CRIEPI. Here, the pulverizing characteristic means the pulverizing work index calculated by unit power ratio to feeding weight of coal and an average diameter of pulverized coal defined by Bond's equation. Pulverizing work index of sub-bituminous coal with low moisture has a good relation with HGI (Hardgrove Grindability Index) as well as that of bituminous coal. When sub-bituminous coal with high moisture is pulverized, this work index becomes much higher than that of low moisture content coal with same HGI. Sub-bituminous coal contains large amount of not only inherent moisture but also adherent moisture. It was found that the large amount of adherent moisture in coal led to the increase of pulverizing work index. Then, the rotation speed of roller in mill decreases. Therefore, it seems that adherent moisture of coal makes the slip of roller over the layer of pulverized coal on the table in mill and efficiency of pulverizing coal decreases. It was found that the increased ratio of pulverizing work index by adherent moisture content becomes high as HGI increases. By taking account of HGI and adherent moisture content, the pulverizing work index is able to be estimated. When sub-bituminous coal is utilized in Japanese coal fired power stations, it is blended with bituminous coal. It is cleared that the pulverizing work index during blending two kinds of coal is also able to be estimated as the weighted mean value between the calculated pulverizing work index of bituminous coal and that of sub-bituminous coal.

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