Patent ID: 8586809

Claim:
A process for producing xylenes by transalkylation of a feed comprising C9+ aromatic hydrocarbon and at least one of C6 and C7 aromatic hydrocarbon, by contact of said feed and hydrogen, optionally provided at least in part by a hydrogen make up stream, with a suitable transalkylation catalyst under suitable transalkylation conditions to produce xylenes, the improvement comprising passing at least one of (i) said feed or a component of said feed selected from the group consisting of C9+ aromatic hydrocarbon, C6 aromatic hydrocarbon, C7 aromatic hydrocarbon, and mixtures thereof, and (ii) said hydrogen make up stream, through an absorber, at ambient conditions and upstream of said contact, said absorber characterized as suitable for absorbing, at said ambient conditions, substantially all of any chloride and/or other halogen and/or halide species in said feed, said component of said feed and/or said make up source of hydrogen; further characterized by: (a) contacting said feed and said hydrogen, downstream of said absorber, with a first catalyst in the presence of hydrogen under conditions effective to dealkylate aromatic hydrocarbons in the feedstock containing C2+ alkyl groups and to saturate C2+ olefins formed so as to produce a first effluent, the first catalyst comprising (i) a first molecular sieve having a Constraint Index in the range of about 3 to about 12 and (ii) at least one first metal or compound thereof of Groups 6 to 12 of the Periodic Table; and then (b) contacting at least a portion of said first effluent with a second catalyst comprising a second molecular sieve having a Constraint Index less than 3 under suitable transalkylation conditions effective to transalkylate C9+ aromatic hydrocarbons with said at least one C6-C7 aromatic hydrocarbon to form a second effluent comprising xylene; and then (c) contacting at least a portion of said second effluent comprising xylene with a third catalyst comprising a third molecular sieve having a Constraint Index in the range of about 3 to about 12 under conditions effective to crack non-aromatic cyclic hydrocarbons in said second effluent and form a third effluent comprising xylene; and (d) recovering xylene from said third effluent.