Heat exchange apparatus for solid particles for double regeneration in catalytic cracking

In an apparatus for regeneration of a fluidized bed of a catalyst contaminated with coke, said apparatus comprising a first regenerator (1) which comprises an enclosure, intake means (2) for spent catalyst, fluidization means (5) and regeneration means for the catalyst using a gas containing oxygen, first separation means (6) in communication with said enclosure of said first regenerator for the regeneration fumes of the catalyst which has been partly regenerated and first removal means (7) for said fumes, a second regenerator superposed over and distinct from the first regenerator, transfer means (10) for said catalyst from the first regenerator to said superposed second regenerator (9) distinct from the first regenerator, the second regenerator comprising an enclosure, means for fluidization and for regeneration (12) of the catalyst which has been regenerated at least in part by a gas containing oxygen, second separation means (17) in communication with the second regenerator for the regeneration fumes from the regenerated catalyst and second means for removal (18) of said fumes separated by the second separation means, the improvement which comprises:

• an external, vertical, elongate heat exchanger (21) having an upper and a lower end, for receiving the hot regenerated catalyst, a valve-less inclined conduit (20) directly connecting said second regenerator to the exchanger (21), said heat exchanger having means (22) therein for cooling the hot catalyst circulating downwardly through the exchanger, said exchanger comprising means (24) for fluidization of the catalyst using a gas at the lower end, said inclined conduit (20) opening into the exchanger (21) at a junction point disposed between the upper end and the lower end of the second regenerator (9) and at a spacing from the upper end (26) thereof in such a way that separation is possible of any regeneration fumes and fluidization gas from the catalyst in the upper part (27) of the exchanger;
• wherein the height of the catalyst in the heat exchanger is maintained substantially the same as the height of the catalyst in the second regenerator;
• means (28) for removal of the fumes and fluidization gas from a discharge zone at the upper part of the exchanger, the means being connected to the second regenerator (9) at a point in the upper part of the of said second regenerator;
• and
• withdrawal and recycling means for circulating the cooled catalyst from the lower end of the exchanger to the first regenerator, said withdrawal and recycling means comprising a lift (36) for lifting the catalyst from below the first regenerator directly into the first regenerator.