Abstract: The composition, microstructure and functional groups of coal-oil co-processing residue were analyzed by elemental analysis, industrial analysis, thermogravimetry, X ray diffraction, scanning electron microscopy and infrared spectroscopy. The content of functional groups was semi-quantitatively calculated by the peak fitting of infrared spectroscopy. The results showed that the organic matter of the residue are composed of lamellar stacking carbon particles, the inorganic matter of residue are composed of coal-oil co-processing catalyst fines and inorganic minerals in coal. The diameters of the residue particles are distributed in around 10 μm and 2 μm. The particles distribute disorderly in integer area and orderly in local area. Volatile, fixed carbon and ash contents were determined by industrial analysis; the results are close to that of thermogravimetric analysis. The hydroxyl self-associating groups in the hydrogen-bond in the residue account for 47.9%, the methylene groups of the aliphatic-hydrogen account for 64%. The oxygen-containing functional groups exist in the form of carbon oxygen bonds and carbonyl groups mainly, and contained tiny silicon oxygen bonds, but without carboxyl group. The aromatic groups contain more alkyl-side-chain substituents, while the aromatic groups with five substituted hydrogen account for only 4.5%.

Key words: coal-oil co-processing, residue, property analysis, functional group