PROCESS FOR TREATING A STREAM OF CRACKED GAS COMING FROM A HYDROCARBON PYROLYSIS PLANT, AND ASSOCIATED PLANT

摘要

This method includes the separation of an upstream partly condensed cracked gas stream in an intermediate separator (44B) in order to recover an intermediate liquid (136), and an intermediate cracked gas stream (138) and the introduction of the intermediate liquid (140) into an intermediate demethanization column (68). The method comprises the sampling of a portion of the intermediate liquid (136) and the expansion of at least one first fraction (194) obtained from the sampled portion (190). It comprises the putting of the first expanded fraction in a heat exchange relationship with the intermediate head stream (146) from the column (68) for at least partly condensing the intermediate head stream (146). The method includes the separation of the intermediate partly condensed head stream in a first reflux separator (76) in order to form a liquid stream (148) introduced into the intermediate column (68) and a combustible gas stream (150).