APU, A NOVEL TECHNOLOGY FOR PRODUCING HIGH PURITY BTX

摘要

High-purity BTX components (benzene, toluene and xylenes) are important building blocks in many chemical processes. In particular, considerable quantities of benzene and paraxylene are used in the production of major petrochemical intermediates for the polymer industry. Naphtha cracking produces light olefins for polymer applications, but also produces pyrolysis gasoline (pygas), which is rich in aromatic compounds and a significant source of BTX. Pygas has been a component in the gasoline pool, but is increasingly used for its higher petrochemical value. This requires the separation of BTX components, via extraction, from aliphatic compounds and C_9+ aromatics. In many cases, naphtha crackers have been extensively debottlenecked to add capacity; however, existing extraction units do not always have the flexibility to support significant capacity increases. Also, due to aromatics limitations in the gasoline pool, the high value of ethylene, propylene and BTX intermediates, the idea of converting C_7+ pygas to these highly desired components is an attractive option.