Tatoray process

The Tatoray process was originally developed by Toray and is currendy Hcensed by UOP (53—57). A schematic of the process is shown in Figure 4. In this process, toluene or a mixture of toluene and Cg aromatics are reacted to form primarily xylenes and benzene. An equiUbrium distribution of xylenes is produced. As shown in Table 4, the ratio of xylenes to benzene can be adjusted by altering the feed ratio to toluene to aromatics. Trimethylbenzenes are the preferred aromatic compound. 

Xylenes. The main appHcation of xylene isomers, primarily p- and 0-xylenes, is in the manufacture of plasticizers and polyester fibers and resins. Demands for xylene isomers and other aromatics such as benzene have steadily been increasing over the last two decades. The major source of xylenes is the catalytic reforming of naphtha and the pyrolysis of naphtha and gas oils. A significant amount of toluene and Cg aromatics, which have lower petrochemical value, is also produced by these processes. More valuable p- or 0-xylene isomers can be manufactured from these low value aromatics in a process complex consisting of transalkylation, eg, the Tatoray process and Mobil s toluene disproportionation (M lDP) and selective toluene disproportionation (MSTDP) processes isomerization, eg, the UOP Isomar process (88) and Mobil s high temperature isomerization (MHTI), low pressure isomerization (MLPI), and vapor-phase isomerization (MVPI) processes (89) and xylene isomer separation, eg, the UOP Parex process (90). 

The Tatoray process, which was developed by Toray Industries, Inc., and is available for Hcense through UOP, can be appHed to the production of xylenes and benzene from feedstock that consists typically of toluene [108-88-3] either alone or blended with aromatics (particularly trimethylbenzenes and ethyl-toluenes). The main reactions are transalkylation (or disproportionation) of toluene to xylene and benzene or of toluene and trimethylbenzenes to xylenes in the vapor phase over a highly selective fixed-bed catalyst in a hydrogen atmosphere at 350—500°C and 1—5 MPa (10—50 atm). Ethyl groups are... 

The MTDP process, which is similar to the Tatoray process, produces an equilibrium composition of xylene isomers. A -xylene yield of 24% in the xylene product is formed at 42—48 wt % toluene conversion over the heterogeneous catalyst at 390—495°C, 4.2 MPa (600 psig), 1 2 Hquid hourly space velocity, and 4 H2/hydrocarbon molar feed ratio. A new ZSM-5 catalyst, which has higher activity and stability than the current catalyst, has been reported (93). 

Xylenes-plus A catalytic process for isomerizing toluene to a mixture of benzene and xylenes. A silica/alumina catalyst is used in a moving bed. It is unlike the related Tatoray process, in that no hydrogen is required. Developed by Sinclair Research in 1964 and then licensed by Atlantic Richfield. 

The catalyst used in the TransPlus process jointly developed by ExxonMobil and CPC uses a proprietary zeolite [76]. From the literature, the SK Energy ATA-11 catalyst appears to be based on either mordenite or beta zeolite using attenuated noble metals. The UOP TAC9 process was developed by UOP and Toray and is licensed by UOP (outside Japan and Korea). The UOP Tatoray process is based on a bi-functional catalyst with long catalyst life, minimal ring loss and hydrogen consumption in comparison with noble metal catalyst systems. 

Application The Tatoray process produces mixed xylenes and petrochemical grade benzene by disproportionation of toluene and transalk-lyation of toluene and C9+ aromatics. 

Description The Tatoray process consists of a fixed-bed reactor and product separation section. The fresh feed is combined with hydrogen-rich recycle gas, preheated in a combined feed exchanger (1) and heated in a fired heater (2). The hot feed vapor goes to the reactor (3). The reactor effluent is cooled in a combined feed exchanger and sent to a product separator (4). 

The Tatoray process unit is capable of processing feedstocks ranging from 100 wt% toluene to 100 wt% Ag+. The optimal concentration of Ag+ in the feed is typically 40-60 wt%. The Tatoray process provides an ideal way to produce additional mixed xylenes from toluene and heavy aromatics. 

Economics The process is designed to function at a much higher level of conversion per pass. This high conversion minimizes the size of the BT columns, and the size of Tatoray process unit, as well as the utility consumption of all of these units. Estimated ISBL costs based on a unit processing feed capacity of 355,000 mtpy (US Gulf Coast site in 2003) ... 

These processes are the Atlantic Richfield Co. (ARCO) xy)eoe pins process, oper ated since 1968 in Houston, Texas, and Toyo Rayon s Tatoray process, commercialized with the assistance of UOP. 

Otani, S., Matsuoka, S., Sato, M., Tatoray process - a new transalkylation process of aromatics developed by Toray. Jap. Chem. Q. 1968 4, 16-18. 

Methyl group transfer can also be effected in the gas phase by the Tatoray process, developed by [/OP and Ibm (Figure 4.29). 

Figure 4.29 Flow diagram of the Tatoray process for producing aromatics from toluene...

This chemistry can be found, for example, in the Tatoray process. A Recycle... 

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