MULTI-STAGE REFORMING PROCESS USING RHENIUM-CONTAINING CATALYST IN THE FINAL STAGE

摘要

This is a process for upgrading a petroleum naphtha fraction. The naphtha is subjected to reforming and the reformate is cascaded to a benzene and toluen e synthesis zone over a benzene and toluene synthesis catalyst comprising a molecular sieve of low acid activity. The preferred molecular sieve is steam ed ZSM-5. The benzene and toluene synthesis zone is operated under conditions compatible with the conditions of the reformer such as temperatures of above about 800 ~F (427 ~C). In one aspect of the invention, the benzene and tolue ne synthesis catalyst includes a metal hydrogenation component from group VII(B ), specifically rhenium. In one mode of operation, the benzene and toluene synthesis catalyst replaces at least a portion of the catalyst in the reformer. The process produces a product containing an increased proportion of benzene, toluene, and/or xylenes, and a reduced portion of alkylated aromatics, as compared to reformate.