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US 5,043,502 AGranted
Production of xylenes from light aliphatic hydrocarbons via dehydrocyclodimerization and methylation
AssigneeUop LLC
InventorsDavid C. Martindale, Paul J. Kuchar
Life of this patent
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Abstract
Aromatic hydrocarbons containing controlled proportions of xylene isomers and benzene may be produced by a process combining dehydrocyclodimerization of C.sub.2 -C.sub.5 aliphatic hydrocarbons, separation of benzene and toluene, and selective methylation.
Claims14
A process for producing benzene and xylenes enriched in a C.sub.8 isomer comprising:
- (a) charging a feed stream comprising a C.sub.2 -C.sub.5 aliphatic hydrocarbon into a dehydrocyclodimerization zone maintained at dehydrocyclodimerization conditions effective to produce a dehydrocyclodimerization zone effluent stream comprising hydrogen, light hydrocarbons, benzene, toluene, and C.sub.8.sup.+ aromatics;
- (b) passing the dehydrocyclodimerization zone effluent stream into a first separation zone maintained at conditions effective to separate entering hydrocarbons into a first process stream comprising benzene and toluene, and a second process stream comprising C.sub.8 aromatics;
- (c) methylating a portion of the benzene and toluene in said first process stream with a methylating compound in a methylation zone maintained at methylation conditions effective to produce a methylation zone effluent stream comprising benzene, toluene, and C.sub.8 aromatics;
- (d) returning at least a portion of the methylation zone effluent stream to the first separation zone;
- (e) passing the second process stream comprising C.sub.8 aromatics to a second separation zone maintained at conditions effective to recover a first product stream comprising said C.sub.8 aromatic isomer.
2 more elements
A process for producing benzene and xylenes enriched in a C.sub.8 isomer comprising:
- (a) charging a feed stream containing a C.sub.2 -C.sub.5 aliphatic hydrocarbon into a dehydrocyclodimerization zone maintained at dehydrocyclodimerization conditions effective to produce a dehydrocyclodimerization zone effluent stream comprising hydrogen, light hydrocarbons, benzene, toluene, and C.sub.8 +aromatics;
- (b) passing the dehydrocyclodimerization zone effluent stream into a first separation zone maintained at conditions effective to separate entering hydrocarbons into a first process stream comprising benzene and toluene, a second process stream comprising C.sub.8 aromatics, and a third process stream comprising hydrogen;
- (c) methylating a portion of the benzene and toluene in said first process stream with a methylating compound in a methylation zone maintained at methylation conditions effective to produce a methylation zone effluent stream comprising benzene, toluene, and C.sub.8 aromatics;
- (d) returning at least a portion of the methylation zone effluent stream to the first separation zone;
- (e) passing the second process stream comprising C.sub.8 aromatics to a second separation zone maintained at conditions effective to separate entering hydrocarbons into a first product stream comprising said C.sub.8 aromatic isomer and a fourth process stream which is depleted in said C.sub.8 aromatic isomer;
- (f) passing the fourth process stream and at least a portion of the third process stream from (b) into an isomerization zone maintained at conditions effective to produce an isomerization zone effluent stream comprising said C.sub.8 isomer;
- and,
- (g) returning at least a portion of the isomerization zone effluent stream to the second separation zone of step (e).
5 more elements
Dependencies are inferred from the claim text.