Conceptual Fluid Catalytic Cracking Process with the Additional Regenerated Catalyst Circulation Path for Gasoline Reprocessing and Upgrading with Minimum Loss

Directly reprocessing fluid catalytic cracking (FCC) gasoline in the FCC unit is a simple method for gasoline upgrading. The gasoline distillate is typically reprocessed in the main riser reactor (i.e., the routine FCC process) or in a secondary riser (i.e., the dual-riser process), but abundant low-value byproducts are yielded during gasoline reformation. In this work, FCC gasoline upgrading was conducted over both the precoked FCC catalysts and the mixtures of regenerated and spent catalysts on a fixed-bed microreactor. Through systematic analysis of the product distribution, gasoline composition, and defined olefin reduction efficiency, a conceptual FCC process with an additional circulation path of the regenerated catalyst into the middle of riser reactor was proposed for gasoline reprocessing and upgrading. In contrast to the routine and dual-riser processes, the as-proposed FCC process was demonstrated to be more efficient in selectively converting the gasoline olefins into high-octane number aromatics and iso-paraffins with minimum loss in gasoline yield.