Resid cracking apparatus with catalyst and adsorbent regenerators and a process thereof

A fluidized bed catalytic cracking apparatus, said apparatus comprising:

• a riser (5) containing a feed stock, regenerated catalyst and adsorbent and having a first inlet means (1) for introduction of high velocity steam, a second inlet means (2) for introduction of the reactivated adsorbent, a third inlet means (3) for introduction of the feed stock containing heavy residual fractions with high concentrations of conradson carbon content, metals including vanadium and nickel and additional poisons including nitrogen, a fourth inlet means (4) for introduction of the regenerated catalyst, an outlet (5A) of riser is connected to riser termination devices/cyclones (9A, 9B, 10A, 10B) for causing separation of hydrocarbon vapors from adsorbent-catalyst mixture, cyclones having dip legs extended towards stripper cum separator (7) drops catalyst-adsorbent mixture close to the interface of catalyst and adsorbent bed;
• a reactor (8) comprising said cyclones and having an outlet means (11) for taking out hydrocarbon vapors and steam mixture to fractionator(s);
• a stripper cum separator (7) located at the bottom of the reactor for causing removal of strippable hydrocarbons from spent catalyst, and coked adsorbent mixture and segregating catalyst from adsorbent;
• said stripper cum separator is with or without baffles/internals, an inlet means (6) at its base for introduction of steam in the upward direction so as to provide a superficial velocity sufficient to strip off all hydrocarbons and to segregate solids into two layers i.e., layer of spent catalyst (33) and another layer of coked adsorbent (32), an outlet means (12) at the bottom of the stripper cum separator for taking out spent catalyst through standpipe via valve means (13), another outlet means (22) at an intermediate location for removing coked adsorbent through stand pipe (22) via valve means (23);
• an adsorbent regenerator (24) located below the level of the lower portion of the stripper cum separator for receiving the coked adsorbent from the intermediate location of the stripper cum separator and causing reactivation of the adsorbent thereof;
• an inlet means (29) in the adsorbent regenerator for introduction of air or oxygen containing gas or steam, an outlet means (30) in flow communication with the second inlet means (2) of the riser for introduction of reactivated adsorbent via stand pipe (31), another outlet means (27) at its top for disposal of flue gas;
• a catalyst regenerator (14) situated above the adsorbent regenerator is connected to stripper cum separator, an inlet (19) at the base of the regenerator for introducing air or oxygen containing gas for effectively burning coke deposited on the catalyst, an outlet (20) in flow communication with the fourth inlet (4) of riser for introduction of regenerated catalyst via slide valve (21) and an outlet means (17) at its top for disposal of flue gas.

A Fluidized catalytic cracking process for converting hydrocarbon residues containing higher concentrations of conradson carbon content, metals including nickel, vanadium, sodium and basic nitrogen into lighter products, said process comprising the steps of;

• a) contacting heavy residue feed stock with hot adsorbent, said adsorbent is lifted with steam from the riser bottom for such contact, to make the heavy residue feed, free from all contaminants;
• b) contacting the feed depleted of contaminants with the catalyst at an intermediate location of the riser to cause catalytic cracking reaction;
• c) transporting the vapor products, the spent catalyst and the coked adsorbent mixture to the riser top pneumatically;
• d) separating the catalyst and the adsorbent from product hydrocarbon vapors in the riser termination device;
• e) separating the spent catalyst and coked adsorbent in a stripper cum separator located below the reactor, at a low temperature, as two distinct layers of spent catalyst and coked adsorbent depending upon the particle size, density and differences in their minimum fluidization velocity, by using steam, so that heavier particles of coked adsorbent are settled at the bottom of the stripper cum separator and the lighter particles of spent catalyst are settled at the intermediate location of the stripper cum separator and all the strippable interstitial hydrocarbons are stripped off from the cracking catalyst and adsorbent mixture in said stripper cum separator;
• f) introducing the coked adsorbent into adsorbent regenerator for partial or complete removal of coke by using air or oxygen containing gas for reactivation;
• g) transporting the reactivated adsorbent into the riser;
• h) transporting portion or full of coked adsorbent into the riser without reactivation;
• i) introducing the spent catalyst into catalyst regenerator for partial or complete regeneration of catalyst using air, oxygen or oxygen containing gases;
• and
• j) transporting the regenerated catalyst into the riser;