FCC process for converting C3/C4 feeds to olefins and aromatics
AssigneeKellogg Brown & Root LLC
InventorsPhillip K. Niccum, Eusebius A. Gbordzoe
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Abstract
A dual riser FCC process for converting C3/C4-containing feedstocks to aromatics. First and second hydrocarbon feeds (5, 6) are supplied to the respective first and second risers (2, 4) in a dual-riser FCC unit with a gallium enriched catalyst to make an effluent rich in ethylene, propylene and aromatics. The first riser (2) is operated at less severe conditions than the second riser (4) and can receive a relatively heavy feed such as gas oil. The feed to the second riser (4) includes propane, for example LPG, propane recycle from the C3 splitter (72), etc. The FCC catalyst can include gallium to promote aromatics formation.
Claims10
1) A fluid catalytic cracking (FCC) process for converting a C3/C4-rich feed to olefins and aromatics, comprising:
- cracking a first hydrocarbon feed in a first riser under first-riser FCC conditions to form a first effluent enriched in cracked hydrocarbons, wherein the first-riser FCC conditions include a residence time from 0.1 to 10 seconds;
- cracking a second hydrocarbon feed comprising light hydrocarbons including hydrocarbons having three carbon atoms, four carbon atoms, or a combination thereof, in a second riser under second-riser FCC conditions to form a second effluent enriched in light olefins and aromatics, wherein the second-riser FCC conditions have a higher severity than the first-riser FCC conditions and include a residence time from 0.1 to 10 seconds and a temperature from 510° C. to 710° C. (950° F. to 1300° F.), wherein the first- and second-riser FCC conditions include a gallium-promoted alumina catalyst;
- recovering the catalyst and separating hydrocarbons including light olefins and aromatics from the first and second FCC effluents;
- regenerating the recovered catalyst by combustion of coke in a common regenerator to obtain hot, regenerated catalyst;
- recirculating the hot regenerated catalyst to the first and second risers.
Dependencies are inferred from the claim text.