Integrated products separation from fluid catalytic cracking and aromatization processes
First Claim
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1. A method for improving the gasoline product yield in a catalytic cracking process comprising the steps of:
- (a) catalytically cracking a hydrocarbon feedstock containing gas oil or heavier fractions to a cracked product stream containing distillate, gasoline, lighter boiling range hydrocarbon fractions, and H2 S, CO2, or both H2 S and CO2 ;
(b) providing a product fractionation section for separating and recovering gasoline and lighter components from said product stream, said product fractionation section including a primary cracked product separation zone, a multistage compressor, and a central debutanizer separator;
(c) flowing a stream containing cracked gasoline and lighter boiling hydrocarbons withdrawn from an upper section of said primary cracked product separation zone to a first accumulation zone to provide a vapor stream enriched in C4 -cracked hydrocarbons containing H2 S, CO2, or both H2 S and CO2, and a liquid stream enriched in C5 +hydrocarbons;
(d) compressing said vapor stream of step (c) in a first stage of said multistage compressor of step (b) to evolve a deacidification charge stream;
(e) deacidifying said deacidification charge stream of step (d) by countercurrently contacting said vapor deacidification charge stream in a first sorption zone with an acid sorbent whereby said acid sorbent becomes enriched in H2 S, CO2, or both H2 S and CO2 ;
(f) withdrawing a deacidified stream enriched in C4 -cracked hydrocarbons from said first sorption zone and flowing said deacidified stream to a second accumulation zone;
(g) contacting a deacidified vapor stream withdrawn from said second accumulation zone of step (f) with a catalyst comprising a zeolite under conversion conditions to convert C4 -cracked hydrocarbon products to a reactor effluent stream containing gasoline boiling range constituents including aromatics;
(h) cooling and at least partially condensing said reactor effluent stream and flowing said cooled reactor effluent stream to a third accumulation zone;
(i) compressing a vapor stream withdrawn from said third accumulation zone in a second stage of said multistage compressor of step (b);
(j) cooling said second stage compressor effluent of step (i) to at least partially condense said second stage compressor effluent;
(k) flowing said at least partially condensed second stage compressor effluent to a fourth accumulation zone to separate said at least partially condensed second stage compressor effluent into a vapor stream enriched in C3 -components and a liquid stream containing C4 +components;
(l) charging liquid product streams from said first accumulation zone, said second accumulation zone, said third accumulation zone, and said fourth accumulation zone to said central debutanizer separator to separate said liquid product streams into a central debutanizer overhead stream enriched in C4 -components and a bottom stream enriched in C5 +gasoline boiling range components; and
(m) flowing a portion of said central debutanizer bottom stream to a second sorption zone to countercurrently sorb and remove C3 +components from said fourth accumulation zone overhead stream of step (l) and recycling said sorbed C3 +components to said fourth accumulation zone.
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Abstract
The present invention provides a process for decreasing the energy consumption of a catalytic cracking process product recovery section while improving gasoline yield by integrating multistage vapor compression and product recovery with deacidification and conversion of C2 -C4 aliphatics to C5 + normally liquid hydrocarbons.
15 Citations
12 Claims
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1. A method for improving the gasoline product yield in a catalytic cracking process comprising the steps of:
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(a) catalytically cracking a hydrocarbon feedstock containing gas oil or heavier fractions to a cracked product stream containing distillate, gasoline, lighter boiling range hydrocarbon fractions, and H2 S, CO2, or both H2 S and CO2 ; (b) providing a product fractionation section for separating and recovering gasoline and lighter components from said product stream, said product fractionation section including a primary cracked product separation zone, a multistage compressor, and a central debutanizer separator; (c) flowing a stream containing cracked gasoline and lighter boiling hydrocarbons withdrawn from an upper section of said primary cracked product separation zone to a first accumulation zone to provide a vapor stream enriched in C4 -cracked hydrocarbons containing H2 S, CO2, or both H2 S and CO2, and a liquid stream enriched in C5 +hydrocarbons; (d) compressing said vapor stream of step (c) in a first stage of said multistage compressor of step (b) to evolve a deacidification charge stream; (e) deacidifying said deacidification charge stream of step (d) by countercurrently contacting said vapor deacidification charge stream in a first sorption zone with an acid sorbent whereby said acid sorbent becomes enriched in H2 S, CO2, or both H2 S and CO2 ; (f) withdrawing a deacidified stream enriched in C4 -cracked hydrocarbons from said first sorption zone and flowing said deacidified stream to a second accumulation zone; (g) contacting a deacidified vapor stream withdrawn from said second accumulation zone of step (f) with a catalyst comprising a zeolite under conversion conditions to convert C4 -cracked hydrocarbon products to a reactor effluent stream containing gasoline boiling range constituents including aromatics; (h) cooling and at least partially condensing said reactor effluent stream and flowing said cooled reactor effluent stream to a third accumulation zone; (i) compressing a vapor stream withdrawn from said third accumulation zone in a second stage of said multistage compressor of step (b); (j) cooling said second stage compressor effluent of step (i) to at least partially condense said second stage compressor effluent; (k) flowing said at least partially condensed second stage compressor effluent to a fourth accumulation zone to separate said at least partially condensed second stage compressor effluent into a vapor stream enriched in C3 -components and a liquid stream containing C4 +components; (l) charging liquid product streams from said first accumulation zone, said second accumulation zone, said third accumulation zone, and said fourth accumulation zone to said central debutanizer separator to separate said liquid product streams into a central debutanizer overhead stream enriched in C4 -components and a bottom stream enriched in C5 +gasoline boiling range components; and (m) flowing a portion of said central debutanizer bottom stream to a second sorption zone to countercurrently sorb and remove C3 +components from said fourth accumulation zone overhead stream of step (l) and recycling said sorbed C3 +components to said fourth accumulation zone. - View Dependent Claims (2, 3, 4)
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5. A method for improving the gasoline product yield in a catalytic cracking process comprising the steps of:
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(a) catalytically cracking a hydrocarbon feedstock containing gas oil or heavier fractions to a cracked product stream containing distillate, gasoline, lighter boiling range hydrocarbon fractions, and H2 S, CO2, or both H2 S and CO2 ; (b) providing a product fractionation section for separating and recovering gasoline and lighter components from said product stream, said product fractionation section including a primary cracked product separation zone, a multistage compressor, and a central debutanizer separator; (c) flowing a stream containing cracked gasoline and lighter boiling hydrocarbons withdrawn from an upper section of said primary cracked product separation zone to a first accumulation zone to provide a vapor stream enriched in C4 -cracked hydrocarbons containing H2 S, CO2, or both H2 S and CO2, and a liquid stream enriched in C5 +hydrocarbons; (d) compressing said vapor stream of step (c) in a first stage of said multistage compressor of step (b); (e) cooling said first stage compressor effluent of step (d) to at least partially condense said first stage compressor effluent; (f) flowing said at least partially condensed first stage compressor effluent to a second accumulation zone to provide a vapor deacidification charge stream containing H2 S, CO2, or both H2 S and CO2, and a second accumulation zone liquid stream enriched in C4 +hydrocarbons; (g) deacidifying said vapor deacidification charge stream of step (f) by countercurrently contacting said vapor deacidification charge stream in a first sorption zone with an acid sorbent whereby said acid sorbent becomes enriched in H2 S, CO2, or both H2 S and CO2 ; (h) withdrawing a deacidified vapor stream enriched in C4 -cracked hydrocarbons from first sorption zone and flowing said deacidified vapor stream to a third accumulation zone; (i) contacting at least a portion of said deacidified vapor stream with a catalyst comprising a zeolite under conversion conditions to convert C4 -cracked hydrocarbon products to a reactor effluent stream containing gasoline boiling range constituents including aromatics; (j) cooling and at least partially condensing said reactor effluent stream and flowing said cooled reactor effluent stream to a fourth accumulation zone; (k) compressing a vapor stream withdrawn from said fourth accumulation zone in a second stage of said multistage compressor of step (b); (l) cooling said second stage compressor effluent of step (k) to at least partially condense said second stage compressor effluent; (m) flowing said at least partially condensed second stage compressor effluent to a fifth accumulation zone to separate said at least partially condensed second stage compressor effluent into a vapor stream enriched in C3 -components and a liquid stream containing C4 +components; (n) charging liquid product streams from said first accumulation zone, said second accumulation zone, said fourth accumulation zone, and said fifth accumulation zone to said central debutanizer separator to separate said liquid product streams into a central debutanizer overhead stream enriched in C4 -components and a bottom stream enriched in C5 +gasoline boiling range components; (o) flowing a portion of said central debutanizer bottom stream to a second sorption zone to countercurrently sorb and remove C3 +components from said fifth accumulation zone overhead stream of step (m) and recycling said sorbed C3 +components to said fifth accumulation zone; and (p) recycling at least a portion of said central debutanizer overhead stream to said catalytic conversion step (i). - View Dependent Claims (6, 7, 8)
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9. A method for improving the gasoline product yield in a catalytic cracking process comprising the steps of:
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(a) catalytically cracking a hydrocarbon feedstock containing gas oil or heavier fractions to a cracked product stream containing distillate, gasoline, lighter boiling range hydrocarbon fractions, and H2 S, CO2, or both H2 S and CO2 ; (b) providing a product fractionation section for separating and recovering gasoline and lighter components from said product stream, said product fractionation section including a primary cracked product separation zone, a multistage compressor, and a central debutanizer separator; (c) flowing a stream containing cracked gasoline and lighter boiling hydrocarbons withdrawn from an upper section of said primary cracked product separation zone to a first accumulation zone to provide a vapor stream enriched in C4 -cracked hydrocarbons containing H2 S, CO2, or both H2 S and CO2, and a liquid stream enriched in C5 +hydrocarbons; (d) compressing said vapor stream of step (c) in a first stage of said multistage compressor of step (b); (e) cooling said first stage compressor effluent of step (d) to at least partially condense said first stage compressor effluent; (f) flowing said at least partially condensed first stage compressor effluent to a second accumulation zone to provide a vapor deacidification charge stream containing H2 S, CO2, or both H2 S and CO2, and a second accumulation zone liquid stream enriched in C4 +hydrocarbons; (g) deacidifying said vapor deacidification charge stream of step (f) by countercurrently contacting said vapor deacidification charge stream in a first sorption zone with an acid sorbent whereby said acid sorbent becomes enriched in H2 S, CO2, or both H2 S and CO2 ; (h) withdrawing a deacidified vapor stream enriched in C4 -cracked hydrocarbons from first sorption zone and flowing said deacidified vapor stream to a third accumulation zone; (i) contacting a deacidified vapor stream withdrawn from said third accumulation zone of step (h) with a catalyst comprising a zeolite under conversion conditions to convert C4 -cracked hydrocarbon products to a reactor effluent stream containing gasoline boiling range constituents including aromatics; (j) cooling and at least partially condensing said reactor effluent stream and flowing said cooled reactor effluent stream to a fourth accumulation zone; (k) compressing a vapor stream withdrawn from said fourth accumulation zone in a second stage of said multistage compressor of step (b); (l) cooling said second stage compressor effluent of step (k) to at least partially condense said second stage compressor effluent; (m) flowing said at least partially condensed second stage compressor effluent to a fifth accumulation zone to separate said at least partially condensed second stage compressor effluent into a vapor stream enriched in C3 -components and a liquid stream containing C4 +components; (n) charging liquid product streams from said first accumulation zone, said second accumulation zone, said fourth accumulation zone, and said fifth accumulation zone to said central debutanizer separator to separate said liquid product streams into a central debutanizer overhead stream enriched in C4 -components and a bottom stream enriched in C5 +gasoline boiling range components; (o) flowing a portion of said central debutanizer bottom stream to a second sorption zone to countercurrently sorb and remove C3 +components from said fifth accumulation zone overhead stream of step (m) and recycling said sorbed C3 +components to said fifth accumulation zone; and (p) recycling at least a portion of said central debutanizer overhead stream to said catalytic conversion step (i). - View Dependent Claims (10, 11, 12)
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Specification