Abstract: The toluene disproportionation and alkylbenzene transalkylation unit of a aromatics plant adopts ExxonMobil's Transplus technology and the three-bed catalyst EM-1100 system. After a year of stable running, in order to improve the flexibility of the plant and to make full use of the remaining space in the reactor, 40 t of HAT-099 catalysts developped by Shanghai Petrochemical Research Institute of SINOPEC were added to the top layer on the existing catalyst in the reactor. By analyzing the conversion, selectivity, aromatics loss rate and C₈ aromatics product quality, the performance of the two catalysts used in the disproportionation unit was investigated. The results show that the combined use of the two catalysts is effective, and the operating conditions and main performance indexes are improved under the condition of constant feed rate.

Key words: toluene disproportionation, catalysts, aromatics, transalkylation, xylene