Abstract: With the deterioration and heaviness of crude oil, the metal content in crude oil has increased significantly. PetroChina Sichuan Petrochemical Co., Ltd.frequently experiences excessive iron and calcium content in the feedstock of residue hydrotreating and catalytic cracking units, which seriously affects the operation and efficiency improvement of refinery units. After technical research, the NS-736 crude oil demetallization agent was selected and used in 10 Mt/a atmospheric and vacuum distillation unit. With all operating parameters of the unit unchanged, the removal effect of the demetallization agent on iron and calcium in crude oil was investigated. The crude oil acid value, drainage pH and COD remained stable without adverse effects, and the equilibrium catalyst index of the catalytic cracking unit was significantly improved. The results show that the removal rates of iron and calcium in crude oil by NS-736 demetallization agent reached 73.1% and 84.9% respectively, which were higher than thatby other agents. The iron content in catalytic cracking feedstock decreased from 16.9mg/L to 6.6mg/L, the efficiency of catalytic cracking unit was significantly improved, and the "bottleneck" problem was solved.

Key words: demetallization agent, catalytic cracking, iron contamination, catalyst