Regenerator for catalytic cracking unit with external cyclones

Method of separating a mixture of gas and solid particles derived from a regenerator of a catalytic cracking unit, the said regenerator comprising a vessel of which a first part is occupied by a dense fluidized bed of catalyst particles and a second part, arranged above the first part, is occupied by a fluidized bed of low catalyst-particle density with respect to the dense bed,

• in which the gases and solids from the low-density bed pass through an internal device situated inside the vessel of the regenerator and are then collected at the outlet of the vessel by at least one separation cyclone situated outside the said vessel,
• in which the solid particles recovered by the external cyclone(s) are returned into the vessel, under the internal device, without passing through the latter, and
• in which the said internal device covers, by projection onto the plane of the cross section of the vessel of the regenerator, at least 80% of the free area of the vessel of the regenerator, the said internal device being made up of one or more individual elements, each individual element being made up of one or more stages of plates which are inclined, each stage being made up of plates that criss-cross one another.