DEASPHALTING AND CHARACTERIZATION OF A SYNCRUDE OBTAINED BY DIRECT LIQUEFACTION OF A SPANISH SUBBITUMINOUS COAL

A syncrude obtained by direct liquefaction of a Spanish subbituminous coal was deasphalted as a previous step of upgrading to get a better f eedstock for further processing. Deasphalting was carried out by ultra sonic extraction with n-hexane. Raw and deasphalted coal syncrudes hav e been fractionated into six fractions by an extrographic procedure th at utilizes six eluents of increasing polarity. Each fraction has been analyzed by FTIR, gas chromatography, GC-MS and high resolution mass spectrometry. Deasphalting removed 36 % of nitrogen, 44 % of sulphur a nd 47 % of oxygen. Nevertheless, the deasphalted liquids would require further removal of heteroatoms by hydroprocessing. Polynuclear aromat ic compounds appeared in all extrografic fractions. Nitrogen-containin g compounds have been found in the fractions III, IV and V, when polar solvents have been used. Some mixed heterocyclic compounds (N-O, N-S) have been observed in the most polar fractions (V and VI).