Coal volatile yield and element partition in rapid pyrolysis

Abstract

The volatile yields from thirteen coals, varying in rank from lignite to anthracite, were measured under conditions of high heating rate (10 5Ks −1) and high temperature (1600–2400 K) representative of pulverized coal combustion and were related to coal characteristics as determined in standard laboratory tests. Positive correlations with coal reflectance and elemental composition were obtained. The distribution of coal elements between the volatiles and residual char was also investigated. The results show that hydrogen and oxygen from the coal are preferentially distributed in the volatile phase. Coal nitrogen evolution parallels the total volatiles at high temperature, whereas coal sulphur is preferentially retained in the char and no relationship between S evolution and coal rank is evident. These results are discussed in relation to the prevalent active groups in the various ranks of coal.