A new approach for gasoline upgrading: Coupling octane enhancement and desulfurization of heavy straight-run naphtha over Ni/HZSM-5 catalyst

Reactive Adsorption Desulfurization Coupling Olefin Conversion in Fluid Catalytic Cracking Gasoline Upgrading Process

Reactive adsorption desulfurization experiments were carried out on fluid catalytic cracking gasoline over a Ni/ZnO adsorbent in a fixed bed reactor. Results demonstrated that desulfurization is accompanied by hydrogen transfer, while isomerization and aromatization reactions are rare. Reactive adsorption desulfurization coupling olefin conversion was attempted by mixing a catalyst consisting Zn-ZSM-5 with an adsorbent at a certain proportion. The process reduced the loss of octane number and sustained ultradeep desulfurization ability simultaneously. An Fe-modified Ni/ZnO adsorbent was developed, which possessed better olefin retention ability than the Ni/ZnO adsorbent. The Ni-Fe/ZnO adsorbent mixed catalyst exhibited better olefin conversion performance and lower octane number loss than that of the Ni/ZnO adsorbent mixed catalyst because more olefins were retained for isomerization and aromatization reaction on the catalyst. The proportion of the catalyst added and the operating conditions of the process were optimized, ultralow sulfur gasoline was produced, and loss of octane number was low under optimal operating conditions. The amount of octane number lost was reduced by 85% compared with conventional reactive adsorption desulfurization. In addition, the process exhibited excellent desulfurization and olefin conversion performance in multiple regeneration cycles, demonstrating the feasibility of continuous processing.