Method for treating pyrolysis oils for recycling in a catalytic cracking unit of hydrorefining units

A process for treating a pyrolysis feedstock, comprising a plastic and/or tire and/or solid recovered fuel pyrolysis oil comprising halogenated compounds, said process comprising:

• a) a hydrotreating step carried out in a hydrotreating reaction section comprising at least one hydrotreating catalyst, said hydrotreating reaction section being fed at least with the pyrolysis feedstock and a gas stream comprising hydrogen, said hydrotreating reaction section being used at an average temperature of between 100° C. and 220° C., a partial pressure of hydrogen of between 1.0 and 3.0 MPa abs., and an hourly space velocity of between 0.05 and 5 h−1, the hydrogen coverage being between 5 and 50 Nm3 of hydrogen per m3 of pyrolysis feedstock, in order to obtain a partially hydrotreated effluent having hydrocarbon compounds with a reduced halogen content,
• b) a separation step, fed with the partially hydrotreated effluent from step a) and an aqueous solution in order to obtain at least a gaseous effluent, an aqueous effluent and a partially hydrotreated hydrocarbon effluent, and
• c) a step of fluid catalytic cracking or hydrorefining of a petroleum feedstock and/or a feedstock resulting from biomass conversion in which at least one portion of the partially hydrotreated hydrocarbon effluent from step b) is introduced as a co-feedstock, said partially hydrotreated hydrocarbon effluent from step b) being introduced without first undergoing another hydrotreating step carried out at higher temperature and/or pressure than the temperature and/or pressure of step a), the mixture of said petroleum feedstock and/or said feedstock resulting from biomass conversion and the partially hydrotreated hydrocarbon effluent from step b) having a halogen content of less than or equal to 10 ppm by weight.