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US 10,239,802 B2Granted
Processes and apparatuses for toluene methylation in an aromatics complex
AssigneeUop LLC
InventorsDavid S. Krimsky, Robert B. Larson
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Abstract
This present disclosure relates to processes and apparatuses for toluene methylation in an aromatics complex for producing paraxylene. More specifically, the present disclosure relates to processes and apparatuses wherein a toluene methylation zone is integrated within an aromatics complex for producing paraxylene thus allowing no benzene byproduct to be produced. This may be accomplished by incorporating a toluene methylation process into the aromatics complex and recycling the benzene to the transalkylation unit the aromatics complex.
Claims18
A process for producing paraxylene with no benzene byproduct, comprising:
- a) passing a lighter aromatic stream containing benzene and a heavier aromatic stream containing C9-C10 aromatic compounds to a transalkylation zone;
- b) subjecting the lighter aromatic stream and the heavier aromatic stream in the transalkylation zone to transalkylation conditions including the presence of a first catalyst to provide a transalkylation product stream having a greater concentration of toluene to C8 aromatics;
- c) separating by fractionation from the transalkylation product stream a first boiling fraction comprising benzene, a second boiling fraction comprising toluene, a third boiling fraction comprising C8 aromatics and a fourth boiling fraction comprising C9+ aromatics;
- d) recycling at least a portion of the benzene from the transalkylation product stream back to the transalkylation zone;
- e) passing at least a portion of the second boiling fraction from steps c, g and i and a methanol stream to a toluene methylation zone operating under toluene methylation conditions to produce a toluene methylation product stream;
- f) separating by fractionation from the toluene methylation product stream the same fractions described in step c;
- g) subjecting at least a portion of the third boiling fraction comprising C8 aromatics of steps c, g and i to a separation zone to selectively remove a para-xylene product and provide a non-equilibrium mixture of C8 aromatics;
- and
- h) passing the non-equilibrium mixture of C8 aromatics from step g to the transalkylation zone.
6 more elements
A process for producing paraxylene with no benzene byproduct, comprising:
- a) passing a lighter aromatic stream containing benzene and a heavier aromatic stream containing C9-C10 aromatic compounds to a transalkylation zone;
- b) subjecting the lighter aromatic stream and the heavier aromatic stream in the transalkylation zone to transalkylation conditions including the presence of a first catalyst to provide a transalkylation product stream having a greater concentration of toluene to C8 aromatics;
- c) separating by fractionation from the transalkylation product stream a first boiling fraction comprising benzene, a second boiling fraction comprising toluene, a third boiling fraction comprising C8 aromatics and a fourth boiling fraction comprising C9+ aromatics;
- d) recycling at least a portion of the benzene from the transalkylation product stream back to the transalkylation zone;
- e) passing at least a portion of the second boiling fraction from steps c, g and i and a methanol stream to a toluene methylation zone operating under toluene methylation conditions to produce a toluene methylation product stream;
- f) separating by fractionation from the toluene methylation product stream the same fractions described in step c;
- g) subjecting at least a portion of the third boiling fraction comprising C8 aromatics of steps c, g and i to a separation zone to selectively remove a para-xylene product and provide a non-equilibrium mixture of C8 aromatics;
- h) subjecting a portion of the non-equilibrium mixture of C8 aromatics to xylene isomerization conditions including the presence of a second catalyst to provide an isomerization product;
- i) passing a portion of the non-equilibrium mixture of C8 aromatics form step g to the transalkylation zone;
- and
- j) separating by fractionation from the isomerization product stream the same fractions described in step c.
8 more elements
Dependencies are inferred from the claim text.