A feed nozzle assembly for co-currently introducing gas and liquid into a reactor vessel which feed nozzle assembly comprises (a) an inner tube defining a gas conduit and an outer tube arranged around the inner tube, wherein the outer surface of the inner tube and the inner surface of the outer tube define an annular liquid conduit, and wherein each of the tubes have an inlet end and an opposite outlet end; (b) a first nozzle attached to the outlet end of the inner tube; (c) a second nozzle attached to the outlet end of the outer tube and arranged downstream of the first nozzle, wherein the inner tube contains purging orifices.