Method for processing plastic pyrolysis oils with a view to their use in a steam-cracking unit

A process for treating a feedstock comprising a plastics pyrolysis oil, comprising:

• a) performing a selective hydrogenation in a reaction section fed with a liquid phase feedstock comprising a plastics pyrolysis oil and a gaseous stream comprising hydrogen, in the presence of at least one selective hydrogenation catalyst, under hydrogen partial pressure and temperature conditions that maintain the liquid phase, said selective hydrogenation being performed at a temperature of between 100 and 250° C., a partial pressure of hydrogen of between 1.0 and 10.0 MPa abs., and an hourly space velocity of between 1.0 and 10.0 h−1, to obtain a hydrogenated effluent;
• b) performing a hydrotreatment in a hydrotreatment reaction section, comprising a fixed-bed reactor containing n catalytic beds, n being an integer greater than or equal to 1, placed in series and each comprising at least one hydrotreatment catalyst, said hydrotreatment reaction section being fed, at the first catalytic bed, with said hydrogenated effluent obtained from a) and a gaseous stream comprising hydrogen, said hydrotreatment being performed at a temperature of between 250 and 430° C., a partial pressure of hydrogen of between 1.0 and 10.0 MPa abs., and an hourly space velocity of between 0.1 and 10.0 h−1, to obtain a hydrotreatment effluent;
• and
• c) performing a separation c) wherein the hydrotreatment effluent obtained from b) and an aqueous solution are fed to a washing and separation section, said separation being performed at a temperature of between 50 and 370° C., to obtain at least one gaseous effluent, an aqueous effluent, and a hydrocarbon effluent, wherein separation c) further comprises injection of the aqueous solution into the hydrotreatment effluent from b), upstream of the washing and separation section.