open access

https://hdl.handle.net/2115/79338

Functional Forms of Nitrogen and Sulfur in Coals and Fate of Heteroatoms during Coal Carbonization

日本語

sulfur distribution

2012-05

日本鉄鋼協会

鉄と鋼

98(5)

161-169

The functionalities of the nitrogen (coal-N) and sulfur (coal-S) present in three caking coals with carbon contents of 76-81 wt%-dry and the fate of these heteroatoms during coal carbonization have mainly been studied by the X-ray photoelectron spectroscopy (XPS) and with a fixed bed quartz reactor, respectively. The XPS measurements exhibit that about 80-90 % of the coal-N exists as pyrrolic-N and pyridinic-N, and the rest can be assigned to quaternary-N (pyridinic-N associated with the hydroxyl groups from phenols or carboxylic acids), whereas the coal-S consists of thiophenic-S, alkyl-S and FeS2, and the proportion of the former is as high as 60-70 %. When the coal sample is carbonized in He at a heating rate of 3°C/min, yield of N-containing species observed at 1000°C increases in the order of HCN ≤ tar-N < NH3 < N2 < oil-N < coke-N, regardless of the type of coal, and the latter two are present predominantly as NH4+ and in polynuclear aromatic structures, respectively. On the other hand, yield of S-containing species at 1000°C increases in the order of COS < CS2 < tar-S < oil-S < H2S < coke-S with all coals, and more than 95 % of the coke-S can be regarded as thiophenic-S. These tendencies are also observed with physical mixtures of each coal investigated. Possible mechanisms for the formation of gaseous N- or S-containing compounds in the carbonization process are discussed on the basis of the results of some thermodynamic calculations.

学術雑誌論文

Version of Record

著作権は日本鉄鋼協会にある

0021-1575

1883-2954

AN00151251