Back to results
US 7,288,687 B1Granted
Integrated process for aromatics production
AssigneeUop LLC
InventorsStanley J. Frey, Gavin P. Towler
Life of this patent
Estimating the term…
Abstract
An aromatics complex flow scheme has been developed in which C7-C8 aliphatic hydrocarbons are recycled to an isomerization unit of a xylene recovery zone to increase the efficiency of the isomerization unit. This improvement results in an aromatics complex with savings on capital and utility costs and an improvement on the return on investment.
Claims18
A process for isomerizing xylenes comprising:
- (a) introducing a feed stream comprising benzene, toluene, and C5-C8 aliphatic hydrocarbons into an extractive distillation zone and separating a bottoms aromatic hydrocarbons stream comprising benzene and toluene, a sidecut aliphatic hydrocarbons stream comprising C7-C8 aliphatic hydrocarbons, and an overhead aliphatic hydrocarbons stream comprising C5-C7 aliphatic hydrocarbons;
- (b) treating the sidecut aliphatic hydrocarbons stream comprising C7-C8 aliphatic hydrocarbons to generate a substantially solvent free sidecut aliphatic hydrocarbons stream comprising C7-C8 aliphatic hydrocarbons;
- (c) introducing the substantially solvent free sidecut aliphatic hydrocarbons stream comprising C7-C8 aliphatic hydrocarbons, hydrogen, and a non-equilibrium xylene stream comprising a non-equilibrium mixture of xylenes into an isomerization zone to contact an isomerization catalyst at isomerization conditions and generate an isomerization zone effluent comprising para-xylene.
A process for producing benzene and para-xylene from a naphtha feedstock comprising the steps of:
- (a) providing a naphtha feed feedstock stream to a hydrotreating zone, wherein the feedstock is contacted with a hydrotreating catalyst under hydrotreating conditions to produce a hydrotreated naphtha stream;
- (b) passing the hydrotreated naphtha stream to a reforming zone, wherein said hydrotreated naphtha is contacted with a reforming catalyst under reforming conditions to produce a reformate stream comprising aromatic components and wherein gases and C4 and lighter hydrocarbons are removed in the reforming zone resulting in the reformate stream being substantially free of gases and C4 and lighter hydrocarbons;
- (c) separating the reformate stream and an isomerization product stream, or a combined stream thereof, in a reformate splitter fractionation zone to produce a toluene and lighter hydrocarbon enriched stream and a xylene and heavier hydrocarbon enriched stream;
- (d) passing the toluene and lighter hydrocarbon enriched stream to an extractive-distillation zone to produce a raffinate stream, a stream containing C7 to C8 aliphatic hydrocarbons, and a benzene and toluene enriched stream;
- (e) separating the benzene and toluene enriched stream in a fractionation column to produce a benzene-enriched stream and a first toluene-enriched stream and recycling the first toluene-enriched stream to a transalkylation zone to contact a metal-stabilized transalkylation catalyst under transalkylation conditions and produce a transalkylation product stream;
- (f) separating the transalkylation product stream into a second toluene-enriched stream and a first xylene-enriched stream;
- (g) separating the first xylene-enriched stream and the xylene and heavier hydrocarbon enriched stream of step (c) in a xylene fractionation zone to produce a second xylene-enriched stream and a stream rich in C9 and C10 alkylaromatic hydrocarbons and C11+ components;
- (h) separating the a stream rich in C9 and C10 alkylaromatic hydrocarbons and C11+ components into a stream rich in C9 and C10 alkylaromatic hydrocarbons and a stream rich in C11+ components;
- (i) passing the second toluene-enriched stream and the stream rich in C9 and C10 alkylaromatic hydrocarbons, or the combination thereof, to the transalkylation zone;
- (j) passing the second xylene-enriched stream from the xylene fractionation zone to a para-xylene separation zone, wherein para-xylene is concentrated into a para-xylene enriched product stream and a para-xylene separation zone effluent stream;
- and
- (k) passing hydrogen, the para-xylene separation zone effluent stream, and the stream containing C7 to C8 aliphatic hydrocarbons, to a xylene isomerization zone wherein said stream is contacted with an isomerization catalyst under isomerization conditions to produce the isomerization product stream of step (c).
9 more elements
A process for producing benzene and para-xylene from a naphtha feedstock comprising the steps of:
- (a) providing a naphtha feed feedstock stream to a hydrotreating zone, wherein the feedstock is contacted with a hydrotreating catalyst under hydrotreating conditions to produce a hydrotreated naphtha stream;
- (b) passing the hydrotreated naphtha stream to a reforming zone, wherein said hydrotreated naphtha is contacted with a reforming catalyst under reforming conditions to produce a reformate stream comprising aromatic components and wherein gases and C4 and lighter hydrocarbons are removed in the reforming zone resulting in the reformats stream being substantially free of gases and C4 and lighter hydrocarbons;
- (c) separating the reformate stream and an isomerization product stream, or a combined stream thereof, in a reformate splitter fractionation zone to produce a toluene and lighter hydrocarbon enriched stream and a xylene and heavier hydrocarbon enriched stream;
- (d) passing the toluene and lighter hydrocarbon enriched stream to an extractive-distillation zone to produce a stream containing C5 to C8 aliphatic hydrocarbons, and a benzene and toluene enriched stream;
- (e) treating the stream containing C5 to C8 aliphatic hydrocarbons to generate a substantially solvent-free stream containing C5 to C8 aliphatic hydrocarbons;
- (f) separating the substantially solvent-free stream containing C5 to C8 aliphatic hydrocarbons into a C5-C7 aliphatic hydrocarbon stream and a C7-C8 aliphatic hydrocarbon stream;
- (g) separating the benzene and toluene enriched stream in a fractionation column to produce a benzene-enriched stream and a first toluene-enriched stream and recycling the first toluene-enriched stream to a transalkylation zone to contact a metal-stabilized transalkylation catalyst under transalkylation conditions and produce a transalkylation product stream;
- (h) separating the transalkylation product stream into a second toluene-enriched stream and a first xylene-enriched stream;
- (i) separating the first xylene-enriched stream and the xylene and heavier hydrocarbon enriched stream of step (c) in a xylene fractionation zone to produce a second xylene-enriched stream and a stream rich in C9 and C10 alkylaromatic hydrocarbons and C11+ components;
- (j) separating the stream rich in C9 and C10 alkylaromatic hydrocarbons and C11+ components into a stream rich in C9 and C10 alkylaromatic hydrocarbons and a stream rich in C11+ components;
- (k) passing the second toluene-enriched stream and the stream rich in C9 and C10 alkylaromatic hydrocarbons, or the combination thereof, to the transalkylation zone;
- (l) passing the second xylene-enriched stream from the xylene fractionation zone to a para-xylene separation zone, wherein para-xylene is concentrated into a para-xylene enriched product stream and a para-xylene separation zone effluent stream;
- and
- (m) passing hydrogen, the para-xylene separation zone effluent stream, and the C7-C8 aliphatic hydrocarbon stream to a xylene isomerization zone wherein said stream is contacted with an isomerization catalyst under isomerization conditions to produce the isomerization product stream of step (c).
11 more elements
Dependencies are inferred from the claim text.