FLASH PYROLYSIS OF COALS - A NEW APPROACH OF CLASSIFICATION

Flash pyrolysis-gas chromatography/mass spectrometry constitutes, in c ombination with statistical methods such as principal component analys is (PCA) and hierachical cluster analysis (HCA), an advantageous techn ique in an attempt to characterize and classify coals of different ori gin. Eight coals comprising three from South Africa, two from Australi a, and one from U.S.A., Columbia and Indonesia, respectively, have bee n pyrolyzed at 750 degrees C. Observed differences in the composition of the pyrolyzate have been elucidated by studying nine parameters: (A ) the content of long-chain aliphatic compounds; (B) the content of be nzene; (C) the content of toluene; (D) the content of toluene in the a romatic fraction; (E) the content of naphthalene relative to the conte nt of benzene + naphthalene; (F) the content of cresols in the aromati c fraction; (G) the content of cresols relative to the content of tolu ene + cresols; (H) the content of o-cresol in the cresol fraction; and (I) the content of styrene relative to the content of naphthalene + s tyrene. The data obtained have been treated statistically by means of PCA and HCA, demonstrating a high degree of similarity between the thr ee South African coals, whereas a somewhat less pronounced similarity between the Australian coals was shown. The results are discussed base d on an analogous study applying conventional coal analyses such as el emental analysis, maceral composition, vitrinite reflectance, ash cont ent, etc. A further comparison with studies applying ash composition d ata has been included.