Germany develops new technologies

Increasingly stringent environmental regulations will limit the total amount of aromatics in gasoline, so that the amount of heavy pyrolysis gasoline (Pygas) transferred to gasoline is also limited. Heavy Pygas is a byproduct of steam cracking, the amount of which depends mainly on the raw materials used for ethylene production. Pygas contains a high aromatic mixture of C7-C9 compounds that provide high octane for gasoline blending. Selective hydrogenation of Pygas removes unsaturated hydrocarbons such as olefins, styrene, and hydrazines. Usually Pygas can be used as a gasoline blender, however, future clean fuel specifications will limit this use.
The new secondary reaction process, the ARINO technology, converts aromatics contained in Pygas to alkanes. The aromatic hydrocarbon ring opening (ARINO) process jointly developed by Southern Chemicals Germany, Linde AG, and Weiba Oil Company can upgrade heavy Pygas to high quality steam cracking raw materials. The process includes two steps of aromatic saturation and cycloalkane ring opening.
Heavy Pygas is first selectively hydrogenated and desulphurized. At medium and intermediate temperatures, the aromatics are saturated with naphthalenes into the naphthalenes. This step is similar to conventional gasoline hydrogenation. Pygas is diluted with the product, mixed with hydrogen, preheated in the feed/effluent heat exchanger, enters the reactor, reacts under a trickle bed in a fixed bed, temperature control is maintained by quenching of the liquid product, heat of reaction is used Cooling water removed. After phase separation, hydrogen and naphthenes are compressed, mixed and passed into a second processing step. Here, the ring is opened and the naphthalenes are converted to alkanes. The catalyst used in this step is a palladium catalyst of a particular molecular sieve support. The feed mixture was preheated and evaporated and then heated to the reaction temperature with a heating furnace. With one-pass operation, reactions occur near isothermal conditions, and process heat is used to generate high-pressure steam. After the heat exchange with the feed, the reaction product is separated, the paraffins are separated from the excess hydrogen by continuous partial condensation, and the separation of the light paraffins requires a very low temperature, and the C2/C3 refrigerant is used to separate in the cold box. .
The product obtained from the ARINO process produces an 80% ethane/propane feed, which is extremely suitable for ethylene plants and can be easily combined into refinery/petrochemical complexes.