Integrated process for producing xylenes and high purity benzene
AssigneeUop LLC
InventorsEdward M. Casey, Patrick J. Silady, Antoine Negiz, Gregory R. Werba
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Abstract
Processes and apparatus are provided that provide high yields of xylenes per unit of aromatic-containing feed while enabling a high purity benzene co-product to be obtained without the need for an extraction or distillation to remove C6 naphthenes. The processes of this invention include a transalkylation section and a disproportionation section in the benzene and toluene-containing feed is directly provided to the transalkylation section and in which a benzene recycle loop in the transalkylation section isolates the disproportionation section from C6 naphthenes.
Claims7
An integrated process for the production of xylenes and highly pure benzene from aromatic feedstocks containing benzene co-boilers comprising:
- a. separating by fractionation a benzene and toluene-containing fraction from said feedstock, said fraction containing benzene co-boilers;
- b. subjecting said benzene and toluene-containing fraction to transalkylation conditions including the presence of C9 and C10 aromatics and a metal-stabilized transalkylation reaction catalyst to provide a transalkylation product stream having a greater concentration of toluene and C8 aromatics;
- c. separating by fractionation from said transalkylation reaction product stream a lower boiling fraction comprising benzene and co-boilers and a higher boiling fraction comprising toluene and having a substantial absence of benzene co-boilers;
- d. recycling at least a portion of the lower boiling fraction from step c to step b sufficient to maintain a benzene to total aromatics mole ratio to step b at least about 0.2:1;
- e. subjecting at least a portion of the higher boiling fraction from step c to disproportionation conditions including the presence of a disproportionation catalyst to provide a disproportionation reaction product containing benzene, toluene, C8 aromatics and less than about 100 ppm-mass-percent benzene co-boilers;
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- f. separating by fractionation from at least a portion of the disproportionation reaction product a lower boiling fraction comprising benzene and less than 2000 ppm-mass benzene co-boilers and a higher boiling fraction comprising C8 aromatics.
Dependencies are inferred from the claim text.