Abstract: The processing volume of high acid number residue oil is gradually increasing, and the problems of high yield of coke and low yield of light oils during processing of high acidic residue oil is attracting more attention. Up to now, there is still lack of clear and consistent understanding about the effects of acidity, asphaltene content and other factors on the thermal behavior of high acidic residue. The effects of carboxylic acid, asphaltene, metal, free radical initiator, coke powder, catalytic slurry on the thermal reaction of representative mixed heavy oil were compared. It was proved that the addition of carboxylic acid, free radical initiators and coke powder into heavy oil promoted the thermal cracking of heavy oil to a certain extent. While asphaltene, metal and the like accelerated the thermal condensation of heavy oil to coke, among which the asphaltene promoted the coke formation more obviously. The results show that the high coke yield of high acidic heavy oil is not caused by the carboxylic acid contained, but by the nature of asphaltene and carbon residue.

Key words: Mixed heavy oil, high acidIc number residue, carboxylic acid, asphaltene, coke yield