Abstract: The conversion of a charge comprising at least one oxygen compound is performed in a reactor C, into which the charge is introduced by the pipe (11), the solid catalytic particles forming the dense phase D1 by the pipe (14) and the solid entrainment gas by the pipe (12). The reactor is connected by a pipe (1) to a cocurrent cyclone separator-mixer (MS) making it possible to separate a solid phase from a gaseous phase containing the conversion products recovered by the pipe (4'), while carrying out a quenching of said gaseous phase by a product M2 introduced by the pipe (3). The phase D1 is fed by the pipe (7) to a regenerator R before being returned by the pipe (13) into the reactor C. The mixture of the gaseous phase and the product M2 is separated in a separator and the product M2, optionally after cooling, is recycled to the mixer-separator (MS).