Investigation of demetallization of Ni and V in crude oil using spherical polyelectrolyte brushes with adjuvant

Nickel and vanadium in crude oil adversely affects the quality of petroleum coke and refining process. Polymer brushes bearing high-density ligands have shown promising nickel removal ability. In this work, submicron polybutadiene (PB) grafted by aminodithio- carbamate acrylamide (PAMDTC@PB) was prepared and characterized by the infrared spectroscopy, dynamic light scattering, and elemental analysis. Based on results of molecular simulation, PAMDTC was selected as ligand molecule at first. Then the nickel and vanadium removal rates by PAMDTC@PB and traditional polyacrylic acid brushes (PAA@PB) were evaluated through the electric desalination process, both in the model and real oil samples. The result shows that S atom in AMDTC is most likely to chelate with metal porphyrin compounds and AMDTC molecule presents highest chelating activity. Compared with PAA@PB, the removal rate of Ni and V porphyrin compounds with the aid of PAMDTC@PB increases significantly, with an optimized removal rate of 46.91 % and 56.81 %. To achieve better metal removal efficiency and higher utilization rate of prepared polymer brushes, sodium dimethyl dithiocarbamate (SDD) is introduced into the electric desalination process as a adjuvant. The results indicate that the addition of SDD leads to a increment of 10–30 % to the removal rate of Ni and V and a reduction of brush dosage by 200–400 ppm in the electric desalination process, exhibiting great potential of industrial applications of novel desalination process with adjuvant.