Abstract: Hainan RDS feedstock and the third generation RHT series catalysts were used for studying RHT process. The optimized catalyst grading and the calculated metal capacity of RHT graded catalysts were investigated. The process experiments were conducted using the best gradation of catalysts and the results indicated that to produce hydrotreated oil with sulfur content lower than 0.20%, the volume space velocity is at least reduced to 0.20 h-1. The stability test to produce hydrotreated oil with the sulfur content lower than 0.17% showed that using the optimized catalysts gradation and the appropriate process conditions (the partial pressure of hydrogen of 15.0 MPa, the standard state volume ratio of hydrogen to oil 700, the volume space velocity 0.20 h-1), the average deactivation rate of third generation RHT series catalysts is 0.082 ℃/d from 1 000 h to 2 000 h, which meets requirement for the long period operation.

Key words: residue hydrotreating, RHT, catalyst grading, operating condition, stability