Exploratory Research On The Demetallization Of Crude Oil By Strengthening Electro-desalting

In the refining process of crude oil, the heavy metals such as nickel and vanadium usually get access to heavy distillate oil like atmospheric pressure residual oil and vacuum residual oil. It's very harmful for the crude oil processing process. When deposited on cracking catalyst, it will affect activity and selectivity, making the target yield dropping; it will also deactivate hydrogenation catalysts; in the process of delay coking, it will cause the increasing yield of coke and gas at the expense of light oil and petroleum coke. Therefore, the demetallization technologies of nickel and vanadium in crude oil have been more and more emphasized both by industry and academic community.Nickel and vanadium in crude oil most exist with the form of large ring of porphyrin compounds. They usually associate with gelatin and asphaltene to make the chemical properties extremely stable, so it is very difficult to remove them by the conventional electro-desalting method. Therefore, in the pretreatment of electro-desalting and dehydration process, a new method is developed to add some demetallization agents, making nickel and vanadium porphyrin and non-porphyrinoil-soluble polymers react with demetallization agents under certain conditions, forming water-soluble chelates to remove them from crude oil.The existing demetallization agents were investigated at first, and the chelations of different coordination atoms such as N, O, S, P with nickel and vanadium were discussed. Then, four functional demetallization agents were synthesized. Two demetallization agents were selected from them to optimize experimental conditions employing YS-3 electro-desalting instrument. The conclusions were as follows:at the conditions of water injection rate of 10%, dosage of demulsifier of lOμg·g-1, dosage of demetallization agents of 2000μg·g-1, the emulsifying machine speed of 8000r·min-1, the emulsification time of 1min, temperature of 110℃, the low electric field intensity of 500V·cm-1, the high electric field intensity of 1200V·cm-1, residence time of 10min and settling time of 30min, the dehydration rate was up to 90%, the demetallization rates of nickel and vanadium wre about 75% and 25% respectively.