# US 7,611,622 B2 · FCC process for converting C3/C4 feeds to olefins and aromatics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,622 B2 - Document ID: US7611622B2 - Status: Granted - Kind: B2 - Application number: 11/648,031 - Filed: 2006-12-29 - Published: 2008-07-03 - Granted: 2009-11-03 - Earliest claimed: 2006-12-29 - Assignees: Kellogg Brown & Root LLC - Inventors: Phillip K. Niccum; Eusebius A. Gbordzoe - Web page: https://patentgrep.com/patent/US7611622B2 ## CPC - C10G 11/18: according to the "fluidised-bed" technique - C10G 11/04: Oxides - C10G 69/04: including at least one step of catalytic cracking in the absence of hydrogen - C10G 2400/30: Aromatics - C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES ## 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. ## Claims ### Claim 1 A fluid catalytic cracking (FCC) process for converting a C3/C4-rich feed to olefins and aromatics, comprising: cracking a first hydrocarbon feed comprising heavy hydrocarbons having greater than 12 carbon atoms 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 having 12 or less carbon atoms, 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 riser and the second riser contain gallium-promoted alumina catalyst; recovering the catalyst from the first riser and the second riser; separating hydrocarbons including light olefins and aromatics from the first and second FCC effluents, wherein the second hydrocarbon feed further comprises a recycle stream comprising propane recovered from the separated hydrocarbons; regenerating the recovered catalyst by combustion of coke in a common regenerator to obtain hot, regenerated catalyst; and recirculating the hot regenerated catalyst to the first and second risers. ### Claim 2 (depends on 1) The FCC process of claim 1, wherein the first hydrocarbon feed comprises gas oil. ### Claim 3 (depends on 1) The FCC process of claim 1 wherein the second hydrocarbon feed comprises liquefied petroleum gas (LPG). ### Claim 4 (depends on 1) The FCC process of claim 1 wherein the second-riser FCC conditions comprise, relative to the first-riser FCC conditions, a higher temperature, higher catalyst-to-oil ratio, lower hydrocarbon partial pressure, lower steam-to-oil ratio, longer residence time, or any combination thereof. ### Claim 5 (depends on 1) The FCC process of claim 1 wherein the recycle stream comprises paraffinic and cycloparaffinic hydrocarbons having from 3 to 12 carbon atoms. ### Claim 6 (depends on 1) The FCC process of claim 1, further comprising: conditioning gas separated from the first and second effluents to remove oxygenates, acid gases, water or a combination thereof to form a conditioned stream; and separating the conditioned stream into at least a tail gas stream, an ethylene product stream, a propylene product stream, a light stream comprising ethane, propane, or a combination thereof, an intermediate stream comprising olefin selected from C4 to C6 olefins and mixtures thereof, and a heavy stream comprising C6 and higher hydrocarbons. ### Claim 7 (depends on 6) The FCC process of claim 6, wherein the first and second effluents are mixed and conditioned together in a common conditioning unit. ### Claim 8 (depends on 6) The FCC process of claim 6, further comprising: hydrotreating at least a portion of the heavy stream to obtain a hydrotreated stream; extracting a product stream comprising benzene, toluene, xylenes or a mixture thereof from the hydrotreated stream to obtain a raffinate stream lean in aromatics; and recycling the raffinate stream to the second riser. ### Claim 9 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 hydrocarbon feed comprises heavy hydrocarbons having greater than 12 carbon atoms, and wherein the first-riser FCC conditions include a residence time from 0.1 to 10 seconds; cracking a second hydrocarbon feed comprising light hydrocarbons having 12 or less carbon atoms, 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 riser and the second riser contain gallium-promoted alumina catalyst; recovering the catalyst from the first riser and the second riser; separating hydrocarbons from the first and second FCC effluents to provide: a light stream comprising ethane, propane, or a combination thereof; an intermediate stream comprising one or more olefins selected from C4 to C6 olefins and mixtures thereof; and a heavy stream comprising C6 and higher hydrocarbons; 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; and recycling the light stream, intermediate stream, and heavy stream to the second riser. ### Claim 10 (depends on 9) The FCC process of claim 9, wherein the first hydrocarbon feed comprises gas oil and the second hydrocarbon feed comprises liquefied petroleum gas (LPG). ### Claim 11 (depends on 9) The FCC process of claim 9, wherein the first hydrocarbon feed comprises gas oil and the second hydrocarbon feed comprises liquefied petroleum gas (LPG). ### Claim 12 (depends on 9) The FCC process of claim 9, further comprising: hydrotreating at least a portion of the heavy stream to obtain a hydrotreated stream; extracting a product stream comprising benzene, toluene, xylenes or a mixture thereof from the hydrotreated stream to obtain a raffinate stream lean in aromatics; and recycling the raffinate stream to the second riser. ### Claim 13 (depends on 9) The FCC process of claim 9, further comprising: conditioning gas separated from the first and second effluents to remove oxygenates, acid gases, water or a combination thereof to form a conditioned stream; and separating the conditioned stream into at least a tail gas stream, an ethylene product stream, a propylene product stream, a light stream comprising ethane, propane, or a combination thereof, an intermediate stream comprising olefin selected from C4 to C6 olefins and mixtures thereof, and a heavy stream comprising C6 and higher hydrocarbons. ### Claim 14 A fluid catalytic cracking (FCC) process for converting a C3/C4-rich feed to olefins and aromatics, comprising: cracking a first hydrocarbon feed comprising a heavy hydrocarbon having greater than 12 carbon atoms 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 having 12 or less carbon atoms 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 riser and the second riser contain gallium-promoted alumina catalyst; recovering the catalyst from the first and second risers; separating hydrocarbons from the first and second FCC effluents to provide: a light stream comprising ethane, propane, or a combination thereof; an intermediate stream comprising one or more olefins selected from C4 to C6 olefins and mixtures thereof; and a heavy stream comprising C6 and higher hydrocarbons; regenerating the recovered catalyst by combustion of coke in a common regenerator to obtain hot, regenerated catalyst; spraying a solution of gallium onto the hot regenerated catalyst; recirculating the hot regenerated catalyst to the first and second risers; and recycling the light stream, the intermediate stream, and the heavy stream to the second riser. ### Claim 15 (depends on 14) The FCC process of claim 14, wherein the first hydrocarbon feed comprises gas oil and the second hydrocarbon feed comprises liquefied petroleum gas (LPG). ### Claim 16 (depends on 14) The FCC process of claim 14, wherein the first hydrocarbon feed comprises gas oil and the second hydrocarbon feed comprises liquefied petroleum gas (LPG). ### Claim 17 (depends on 14) The FCC process of claim 14, wherein the second hydrocarbon feed further comprises a recycle stream recovered from the separated hydrocarbons, wherein the recycle stream comprises propane. ### Claim 18 (depends on 14) The FCC process of claim 14, further comprising: hydrotreating at least a portion of the heavy stream to obtain a hydrotreated stream; extracting a product stream comprising benzene, toluene, xylenes or a mixture thereof from the hydrotreated stream to obtain a raffinate stream lean in aromatics; and recycling the raffinate stream to the second riser.