Catalytic Cracking Method For Treating A Fraction Having A Low Amount of Conradson Carbon

摘要

The present invention discloses a process for the catalytic cracking of a weakly coking feedstock having a Conradson carbon residue of 0.1% by weight and a hydrogen content of greater than 12.7% by weight, comprising at least a feedstock cracking zone, a zone for separating/stripping the effluents from the coked catalyst particles and a zone for regenerating said particles, characterized in that at least a solid carbon material in the fluidized state, having a carbon content equal to or greater than 80% by weight, is injected upstream of and/or during the catalyst regeneration step into a dense bed of coked catalyst.

主权项

1. A process for the catalytic cracking of a weakly coking feedstock having a Conradson carbon residue equal to or less than 0.1% by weight and a hydrogen content equal to or greater than 12.7% by weight, implemented in a unit comprising at least a feedstock cracking zone, a separating/stripping zone for separating/stripping effluents from coked catalyst particles and a regeneration zone for regenerating said coked catalyst particles, characterized in that:
(a) at least a solid carbon material in a fluidized state, having a carbon content equal to or greater than 80% by weight, is dispersed on the coked catalyst particles,
(i) upstream of the regeneration zone and downstream of the separating/stripping zone, and/or(ii) in the regeneration zone for regenerating catalyst within the coked catalyst particles of a dense fluidized bed, (b) an amount of the solid carbon material in the fluidized state dispersed within the coked catalyst particles of the dense fluidized bed is adjusted so as to deliver an additional amount of coke QC to the catalyst so as to satisfy the following equation (I):
Qc=Qt−Qi  (I), in which Qi is an initial coke content of the coked catalyst particles after the feedstock has been cracked and Qt or delta coke is a coke content necessary for maintaining a temperature of regenerated catalyst and therefore a heat balance of the process, (c) a mixture of the coked catalyst particles and the solid carbon material is burnt in the regeneration zone to produce the regenerated catalyst having a reduced content of carbon material, (d) the regenerated catalyst is mixed with the weakly coking feedstock in the feedstock cracking zone to produce the coked catalyst particles and the effluents, (e) and the coked catalyst particles are separated from the effluents in the separating/stripping zone, then the coked catalyst particles are sent back to the regeneration zone.