Fluid catalytic cracking to produce and recover light olefins
First Claim
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1. A process for catalytic cracking a heavy hydrocarbon feedstock and recovering select hydrocarbons including light olefins, the process comprising:
- contacting a heavy hydrocarbon feedstock with a hydrocarbon cracking catalyst in a fluidized reactor zone at effective conditions to produce light olefins to form a fluid catalytic cracker effluent stream comprising a range of hydrocarbons;
separating the fluid catalytic cracker effluent stream in a separation system to form a first separation system stream comprising primarily C4−
hydrocarbons and at least a second separation system stream comprising primarily C5+ hydrocarbons;
cooling at least a portion of the first separation system stream;
then compressing at least a portion of the first separation system stream;
then contacting at least a portion of the first separation system stream in an absorption system with an absorption solvent at effective conditions to absorb a significant portion of C2+ hydrocarbons from the first separation process stream to form a first absorption system stream comprising primarily methane and hydrogen and to form a second absorption system stream comprising a portion of the absorption solvent and C2+ hydrocarbons, wherein the effective conditions to absorb a significant portion of C2+ hydrocarbons in the absorption system comprise a temperature of about 4°
C. to about 27°
C. (about 40°
F. to about 80°
F.);
separating at least a portion of the second absorption system stream to form at least a first process stream comprising at least a portion of the absorption solvent and at least one second process stream comprising a remaining portion of the second absorption system stream; and
returning at least a portion of the first process stream to the absorption system as the absorption solvent.
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Abstract
Processing schemes and arrangements are provided for the processing a heavy hydrocarbon feedstock via fluidized catalytic cracking with selected hydrocarbon fractions including light olefins being obtained via absorption and separation product recovery.
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Citations
20 Claims
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1. A process for catalytic cracking a heavy hydrocarbon feedstock and recovering select hydrocarbons including light olefins, the process comprising:
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contacting a heavy hydrocarbon feedstock with a hydrocarbon cracking catalyst in a fluidized reactor zone at effective conditions to produce light olefins to form a fluid catalytic cracker effluent stream comprising a range of hydrocarbons; separating the fluid catalytic cracker effluent stream in a separation system to form a first separation system stream comprising primarily C4−
hydrocarbons and at least a second separation system stream comprising primarily C5+ hydrocarbons;cooling at least a portion of the first separation system stream; then compressing at least a portion of the first separation system stream; then contacting at least a portion of the first separation system stream in an absorption system with an absorption solvent at effective conditions to absorb a significant portion of C2+ hydrocarbons from the first separation process stream to form a first absorption system stream comprising primarily methane and hydrogen and to form a second absorption system stream comprising a portion of the absorption solvent and C2+ hydrocarbons, wherein the effective conditions to absorb a significant portion of C2+ hydrocarbons in the absorption system comprise a temperature of about 4°
C. to about 27°
C. (about 40°
F. to about 80°
F.);separating at least a portion of the second absorption system stream to form at least a first process stream comprising at least a portion of the absorption solvent and at least one second process stream comprising a remaining portion of the second absorption system stream; and returning at least a portion of the first process stream to the absorption system as the absorption solvent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A process for catalytic cracking a heavy hydrocarbon feedstock and recovering select hydrocarbons including light olefins, the process comprising:
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contacting a heavy hydrocarbon feedstock with a hydrocarbon cracking catalyst in a fluidized reactor zone at effective conditions to produce light olefins to form a fluid catalytic cracker effluent stream comprising a range of hydrocarbons wherein the hydrocarbon cracking catalyst comprises contacting the heavy hydrocarbon feedstock with a catalyst in a fluidized reactor zone at hydrocarbon cracking reaction conditions to produce a cracked stream containing hydrocarbon products including light olefins, the catalyst having a catalyst composition including a first component comprising a large pore molecular sieve and a second component comprising a zeolite with no greater than medium pore size, the zeolite with no greater than medium pore size comprising at least 1.0 wt. % of the catalyst composition; separating the fluid catalytic cracker effluent stream in a separation system to form a first separation system stream comprising primarily C4−
hydrocarbons and at least a second separation system stream comprising primarily C5+ hydrocarbons;contacting at least a portion of the first separation system stream in an absorption system with an absorption solvent at effective conditions to absorb a significant portion of C2+ hydrocarbons from the first separation system stream to form a first absorption system stream comprising primarily methane and hydrogen, and to form a second absorption system stream comprising at least a portion of the absorption solvent, C2+ hydrocarbons and a quantity of at least one impurity selected from the group consisting of hydrogen sulfide, mercaptan, sulfur, water, carbon dioxide, and acetylene; treating at least a portion of the second absorption system stream in a treatment system to remove at least a portion of the impurity; separating at least a portion of the treated second absorption system stream to form a first process stream comprising at least a portion of the absorption solvent, a first separated process stream comprising primarily C2 hydrocarbons, a second separated process stream comprising primarily C3 hydrocarbons, and a residual separated process stream comprising a remaining portion of the second absorption system stream; returning at least a portion of the first process stream to the absorption system as the absorption solvent; separating the first separated process stream in a C2 separation unit to form a first C2 separation unit stream comprising primarily ethylene and a second C2 separation unit stream comprising primarily ethane; and separating the second separated process stream in a C3 separation unit to form a first C3 separation unit stream comprising primarily propylene and a second C3 separation unit stream comprising primarily propane. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A process for catalytic cracking a heavy hydrocarbon feedstock and recovering select hydrocarbons including light olefins, the process comprising:
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contacting a heavy hydrocarbon feedstock with a hydrocarbon cracking catalyst in a fluidized reactor zone at effective conditions to produce light olefins to form a fluid catalytic cracker effluent stream comprising a range of hydrocarbons; separating the fluid catalytic cracker effluent stream in a separation system to form a first separation system stream comprising primarily C4−
hydrocarbons and at least a second separation system stream comprising primarily C5+ hydrocarbons;contacting at least a portion of the first separation system stream in a primary absorption unit with a primary absorption solvent at effective conditions to absorb a significant portion of C2+ hydrocarbons to form a first primary absorption unit stream comprising primarily methane and hydrogen and to form a second primary absorption unit stream comprising at least a portion of the primary absorption solvent, C2+ hydrocarbons, a quantity of light olefins and a reduced quantity of hydrogen and methane; contacting at least a portion of the first primary absorption unit stream in a secondary absorption unit with a secondary absorption solvent comprising a liquid portion of the first separation system stream at effective conditions to absorb light olefins to form a first secondary absorption unit stream comprising primarily methane and hydrogen and a second secondary absorption unit stream comprising a quantity of C2+ hydrocarbons including light olefins; stripping at least a quantity of methane and hydrogen from at least a portion of the second primary absorption unit stream in a stripper unit at effective conditions to form a first stripper unit stream comprising a quantity of hydrogen and methane and a second stripper unit stream comprising at least a portion of the primary absorption solvent and C2+ hydrocarbons including light olefins; and returning at least a portion of the first stripper unit stream to the primary absorption unit; separating at least a portion of the second stripper unit stream to form at least a first process stream comprising at least a portion of the primary absorption solvent and at least one second process stream comprising a remaining portion of the second absorption system stream; and returning at least a portion of the first process stream to the absorption system as the primary absorption solvent. - View Dependent Claims (18, 19, 20)
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Specification