Transalkylation – GT-TransAlk℠

Transalkylation Technology – GT-TransAlk
GT-TransAlk process technology produces benzene and xylenes through transalkylation of the methyl groups from toluene and/or heavy aromatics streams. The technology features a proprietary zeolite catalyst and can accommodate varying ratios of feedstock, while maintaining high activity and selectivity. GT-TransAlk is especially well-suited for processing heavy aromatics (C9-C10+) with a long run length, in order to maximize the production of xylenes from the aromatic feedstock. High purity benzene is produced by simple distillation.

Process Description
The technology encompasses three main processing areas: splitter, reactor, and stabilizer sections. The heavy-aromatics stream (C9+ feed) is fed to the splitter. The overhead C9/C10 aromatic product is the feed to the transalkylation reactor section. The splitter bottoms are exchanged with other streams for heat recovery before leaving the system. The aromatic product is mixed with toluene and hydrogen, vaporized, and fed to the reactor. The reactor gaseous product is primarily unreacted hydrogen, which is recycled to the reactor. The liquid product stream is subsequently stabilized to remove light components. The resulting aromatics are routed to product fractionation to produce the final benzene and xylene products. The reactor is charged with zeolite catalyst, which exhibits both long life and good flexibility to feed stream variations including substantial C10 aromatics. Depending on feed compositions and light components present, the xylene yield can vary from 25% to 32% and C9 conversion from 53% to 67%.

Process Advantages

  • Simple, low cost fixed-bed reactor design; drop in replacement for other catalysts
  • Very high selectivity; benzene purity is 99.9% without extraction
  • Physically stable catalyst
  • Flexible to handle up to 90+% C9+ components in feed with high conversion
  • Catalyst is resistant to impurities common to this service
  • Moderate operating parameters; catalyst can be used as replacement for other transalkylation units or in grass roots designs
  • Decreased hydrogen consumption due to low cracking rates
  • Significant decrease in energy consumption due to efficient heat integration scheme