Abstract: The heavy unstable components rich in asphaltene and toluene insoluble matter in unconverted oil from ebullated-bed residue hydrotreater are important factors affecting the secondary processing performance of unconverted oil. Based on the polarity and charged characteristics of these components, a method of electric field treatment was proposed to remove the heavy unstable components rich in asphaltene and coke from the products of ebullated-bed hydrotreater. The effects of temperature, time, and voltage on removing the unstable components in unconverted oil  from ebullated-bed hydrotreater were investigated. The results showed that under the action of an electric field, increasing temperature, time, and voltage were beneficial to the removal of unstable components; the higher the temperature and voltage, and the longer the time, the higher the content of n-heptane insoluble and toluene insoluble in the precipitate, and the less toluene-insoluble matter in the purified oil. Under the test conditions, the maximum precipitation removal rate(mass fraction) reached 1.4%, the maximum removal rate of toluene insoluble matter in the purified oil was 96.32%, and the highest contents of n-heptane insoluble and toluene insoluble in the precipitates reached 54.66% and 51.55%, respectively. Applying the electric field to remove unstable components in the unconverted oil has little effect on the four component composition of the unconverted oil. The removal of unstable components can greatly reduce the coking tendency of unconverted oil.

Key words: electric field, ebullated-bed, unconverted oil, coking, asphaltene, coke