AM-91-19 ALTERNATIVE C3+ RECOVERY SYSTEM TO FCCU OIL SCRUBBING PROCESS

Description:

This paper describes a gas separation technique developed by Air Products and Chemicals. Inc. (APCI), based on energy-efficient dephlegmator technology. which cryogenically recovers the unabsorbed propylene and heavier hydrocarbons from the treated secondary absorber off-gas. This system. if added to the gas plant, can dramatically increase the overall propylene recovery in excess of 99%. It is 0 recognized that the recovered olefmic hydrocarbons are valuable as feedstock to many high octane upgrading processes such as alkylate. MlBE. isomerization and other olefm conversion and octane producing units, for conversion into transportation fuels. As an alternative, recovered propylene in a C3-rich fraction could be transferred to a petrochemical facility to augment production of chemical or polymer grade propylene. The incremental value of the recovered hydrocarbons over the corresponding fuel value provides the economic driving force for the refiner to incorporate the cryogenic unit into a new or existing vapor recovery unit.