Second-Stage PyGas Hydrogenation Catalyst
The second-stage hydrogenation process of the C6-C8 fraction, also known as pyrolysis gasoline (PyGas), is a critical step in upgrading the C6-C8 fraction from steam cracker effluent. It aims to remove sulfur- impurities and improve its quality for further processing or use. This hydrotreatment process retains valuable aromatics such as benzene, toluene, and xylenes (BTX) for use as chemical feedstocks while fully saturating any remaining olefins to enhance stability, prevent spontaneous polymerization during storage or transportation, and improve the thermal stability of the PyGas fraction.
The feedstock for the second-stage hydrogenation is the partially treated PyGas from the first-stage hydrogenation, where diolefins and some sulfur- impurities have already been removed. After the second-stage hydrogenation, the PyGas is either sent to an aromatics plant for the separation of BTX components for chemical feedstock use or used as a high-octane component in gasoline.