Jong Hyung Lee

Heavy aromatics upgrading using noble metal promoted zeolite catalyst

Publisher Summary Benzene, toluene, and xylenes (BTX) are valuable petrochemical feedstocks that can be produced from less valuable streams or byproducts, such as C 9 + heavy aromatics (HA), in the refinery processes. C 9 + HA can be transalkylated (TA) with toluene, to increase xylene production over zeolite catalysts. Commercially available zeolite catalysts, however, have low activity and tend to deactivate rapidly. The catalysts are also difficult to regenerate. This chapter presents the development of novel noble metal that promoted zeolite catalysts to maximize the conversion of the C 9 + HA and to improve the stability and regenerability of the catalyst. The effort has led to the successful commercialization of a catalyst named as ATA-11. The catalyst is effective in the conversion of C 9 + HA. Xylene yield is high, particularly in the case of toluene and C 9 + HA weight ratio of 30/70. The result is attributed to a complex reaction network. It is proposed that in addition to the transalkylation of toluene and TMB, other reactions such as toluene disproportionation and hydrodealkylation of ethylbenzene (EB), methylethylbenzene (MEB), and propylbenzene (PB) are also important. The catalyst is very stable over more than two years of operation even with H 2 /HC mole ratio as low as 2.8.