Depolymerization method and system

Depolymerization method for recovering a monomer from a polymer, the depolymerization method comprising the successive steps of pyrolizing a feed material containing the polymer in a pyrolysis reactor so as to generate a hot gas stream, removing solid and liquid impurities from the gas stream in a separator and condensing the monomer contained in the gas stream in a condenser,

• wherein the gas stream is transferred from the separator to the condenser via a transfer column extending upwardly from a lower end fluidly connected to an outlet of the separator to an upper end fluidly connected to an inlet of the condenser,
• wherein cold monomer in liquid state is injected into the transfer column, the transfer column being provided with internals configured such that the cold monomer flows downwardly inside the transfer column by gravity, heavy contaminants contained in the gas stream condense in liquid state on the internals and flow back down by gravity towards the bottom of the transfer column with being then transferred to the separator and the temperature of the gas stream decreases from the lower end to the upper end of the transfer column, and wherein the temperature of the gas stream at the outlet of the separator and the inlet of the transfer column is maintained above the boiling point of the monomer and the temperature of the gas stream at the outlet of the transfer column is maintained between the boiling point of the monomer and the boiling point of the monomer+50° C.