PROCESSES AND APPARATUSES FOR TOLUENE METHYLATION IN AN AROMATICS COMPLEX

摘要

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.

主权项

1. A process for producing paraxylene with no benzene byproduct, comprising:
passing a lighter aromatic stream containing benzene and a heavier aromatic stream containing C9-C10 aromatic compounds to a transalkylation zone; 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; 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; recycling at least a portion of the benzene from the transalkylation product stream back to the transalkylation zone; 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; separating by fractionation from the toluene methylation product stream the same fractions described in step c 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; subjecting the non-equilibrium mixture of C8 aromatics to xylene isomerization conditions including the presence of a second catalyst to provide an isomerization product; and separating by fractionation from the isomerization product stream the same fractions described in step c.