A UOP aromatics complex is a combination of process units which are used to convert petroleum naphtha and pyrolysis gasoline into the basic petrochemical intermediates: benzene, toluene, paraxylene and/or ortho-xylene.
The configuration of an aromatics complex depends upon the available feedstock, the desired product slate, and the balance between performance and capital investment. A fully integrated modern complex contains a number of UOP process technologies. The naphtha feed is first sent to a UOP naphtha hydrotreating unit (1) to remove sulfur and nitrogen compounds and then sent to a UOP CCR Platforming unit (2) to reform paraffins and naphthenes to aromatics.
The reformate produced in the CCR Platforming unit is sent to a stabilizer column, which strips off the light ends. The stabilizer bottoms are sent to a reformate splitter (3). The C7 fraction from the overhead of the reformate splitter is sent to a Sulfolane unit (4). The C8+ fraction from the bottom of the reformate splitter is sent to a xylene fractionation section. The UOP Sulfolane unit extracts the aromatics and then individual high-purity benzene and toluene products are recovered in a BT fractionation section (5 & 6). Toluene is usually blended with C9
+ aromatics (A 9+) from the overhead of the heavy aromatics column (7) and charged to a Tatoray unit (8) for production of additional xylenes and benzene. Toluene and heavy aromatics can also be charged to a THDA unit (9) for production of additional benzene. The C 8+ fraction from the bottom of the reformate splitter is charged to a xylene splitter column (10). The bottom of the xylene splitter column is sent to the o-xylene column (14) to separate highpurity o-xylene product and the bottoms are sent to the heavy aromatics column (7).
The xylene splitter overhead is sent directly to a Parex unit (11), where 99.9 wt% pure paraxylene is recovered by adsorptive separation at very high recovery. The raffinate from the Parex unit is almost entirely depleted of paraxylene and is sent to an Isomar unit (12). In the Isomar unit, additional paraxylene is produced by re-establishing an equilibrium distribution of xylene isomers. The effluent from the Isomar unit is sent to a deheptanizer column (13). The bottoms from the deheptanizer are recycled back to the xylene splitter column.
Licensor: UOP LLC, A Honeywell Company