Process for the production of xylenes

摘要

In a process for producing para-xylene, a feed stream comprising C6+ aromatic hydrocarbons is separated into a toluene-containing stream, a C8 aromatic hydrocarbon-containing stream and a C9+ aromatic hydrocarbon-containing stream. The toluene-containing stream is contacted with a methylating agent to convert toluene to xylenes and produce a methylated effluent stream. Para-xylene is recovered from the C8 aromatic hydrocarbon-containing stream and the methylated effluent stream in a para-xylene recovery section to produce a para-xylene depleted stream, which is then contacted with a xylene isomerization catalyst under liquid phase conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream. The C9+-containing stream with a transalkylation catalyst under conditions effective to convert C9+-aromatics to C8−-aromatics and produce a transalkylated stream, which is recycled together with the isomerized stream to the para-xylene recovery section.

主权项

1. A process for producing para-xylene, the process comprising:
(a1) separating a feed stream comprising C6+ aromatic hydrocarbons into at least a toluene-containing stream, a C8 aromatic hydrocarbon-containing stream and a C9+ aromatic hydrocarbon-containing stream; (b1) contacting at least part of the toluene-containing stream with a methylating agent under conditions effective to convert toluene to xylenes and produce a methylated effluent stream; (c1) recovering para-xylene from the C8 aromatic hydrocarbon-containing stream and the methylated effluent stream to produce at least one para-xylene depleted stream; (d1) contacting at least part of the at least one para-xylene depleted stream with a xylene isomerization catalyst under liquid phase conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream; (e1) recycling at least part of the isomerized stream to (c1); (f1) contacting at least part of the C9+-containing stream with a transalkylation catalyst under conditions effective to convert C9+-aromatics to C8−-aromatics and produce a transalkylated stream; and (g1) recycling at least part of the transalkylated stream to (b1) and (c1).