Staged catalytic cracking process
AssigneeABB Lummus Crest Inc.
InventorRobert J. Gartside
Life of this patent
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Abstract
A staged catalytic cracking process and apparatus is disclosed where each stage has a catalyst to oil ratio of at least 15 and there are individual hydrocarbon feeds to each stage and product removal from each stage. There is a residence time profile with the first stage having a short residence time and the successive stages having progressively longer residence times. Further, there is a feed profile with the lighter components of the total feed going to the first stage and the heavier components being fed to the later stages. The apparatus has a generally vertical orientation which permits it to be incorporated into existing cracking units for upgrading and also easily provides for both short and long residence times.
Claims15
A method of cracking hydrocarbonaceous feedstock, the method comprising the steps of:
- a) separating said hydrocarbonaceous feedstock into at least a first feed portion having a lower molecular weight and a second feed portion having a higher molecular weight;
- b) passing hot regenerated catalyst particles from a catalyst regenerator to the bottom portion of a first riser reactor and injecting the first feed portion so as to form a catalyst to feed weight ratio of at least 15;
- c) passing said catalyst particles and first feed portion up through said first riser reactor and into a first reactor vessel whereby said first feed portion is cracked and said catalyst particles are partially spent;
- d) separating said cracked first feed portion from said catalyst particles and discharging said cracked first feed portion;
- e) passing said catalyst particles from said first reactor vessel to the bottom portion of a second riser reactor and injecting the second feed portion so as to form a catalyst to feed weight ratio of at least 15;
- f) passing said catalyst particles and second feed portion up through said second riser reactor and into a second reactor vessel whereby said second feed portion is cracked and said catalyst particles are further spent;
- g) separating said cracked second feed portion from said catalyst particles and discharging said cracked second feed portion;
- and
- h) returning said catalyst particles to said regenerator and regenerating said catalyst particles.
Dependencies are inferred from the claim text.