Process for increased olefin yields from heavy feedstocks
AssigneeExxon Chemical Patents Inc.
InventorsLarry Lee Iaccino, Nicolas P. Coute
Life of this patent
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Abstract
A process for upgrading petroleum feedstocks boiling in the distillate plus range, which feedstocks, when cracked, result in unexpected high yields of olefins. The feedstock is hydroprocessed in at least one reaction zone countercurrent to the flow of a hydrogen-containing treat gas. The hydroprocessed feedstock is then subjected to thermal cracking in a steam cracker or to catalytic cracking in a fluid catalytic cracking process. The resulting product slate will contain an increase in olefins compared with the same feedstock, but processed in by a conventional co-current hydroprocessing process.
Claims20
A process for increasing the yield of olefins from a gas oil boiling range feed stream during cracking which process comprises:
- (a) passing said feed stream to an initial countercurrent reaction zone wherein the feed stream flows countercurrent to upflowing hydrogen-containing treat gas, in the presence of one or more hydrotreating catalysts, wherein said initial countercurrent reaction zone has a non-reaction zone immediately upstream and immediately downstream therefrom;
- (b) passing the liquid and vapor phase effluents from said initial reaction zone to a second countercurrent reaction zone downstream from said initial reaction zone in the presence of one or more hydrocracking catalysts, wherein said second countercurrent reaction zone has a non-reaction zone immediately upstream and immediately downstream therefrom;
- (c) recovering a vapor phase effluent from said second reaction zone in the immediate upstream non-reaction zone, which vapor phase effluent contains hydrogen-containing treat gas, gaseous reaction products, and a vaporized liquid reaction product;
- (d) recovering downstream from said initial reaction zone a heavy liquid product;
- and
- (e) passing the heavy liquid product to a cracking process unit which is selected from the group consisting of thermal cracking process units, and catalytic cracking process units wherein a vapor phase product stream is recovered comprising olefins.
A process for increasing the yield of olefins from a gas oil boiling range feed stream during cracking which process comprises:
- (a) passing said feed stream to an initial countercurrent reaction zone wherein the feed stream flows countercurrent to upflowing hydrogen-containing treat gas, in the presence of one or more hydrotreating catalysts, wherein said initial countercurrent reaction zone has a non-reaction zone immediately upstream and immediately downstream therefrom;
- (b) passing the liquid and vapor phase effluents from said initial reaction zone to a second countercurrent reaction zone downstream from said initial reaction zone in the presence of one or more catalysts selected from the group consisting of hydrocracking catalysts and aromatic saturation catalysts, wherein said second countercurrent reaction zone has a non-reaction zone immediately upstream and immediately downstream therefrom;
- (c) recovering a vapor phase effluent from said second reaction zone in the immediate upstream non-reaction zone, which vapor phase effluent contains hydrogen-containing treat gas, gaseous reaction products, and a vaporized liquid reaction product;
- (d) recovering downstream from said initial reaction zone a heavy liquid product;
- and
- (e) passing the heavy liquid product to a cracking process unit which is selected from the group consisting of thermal cracking process units, and catalytic cracking process units wherein a vapor phase product stream is recovered comprising olefins;
- wherein said liquid phase reaction product is passed to one or more downstream cocurrent reaction zones comprising hydroprocessing catalysts operated at hydroprocessing conditions;
- and
- wherein, downstream of all reaction zones, said vaporized liquid reaction product is condensed and combined with said heavy liquid product and sent to a cracking process unit.
Dependencies are inferred from the claim text.