A series of Ni/ZnO adsorbents containing promoters (Fe, Mo, and W) were prepared for reducing the loss of the octane number because of olefin saturation during the reactive adsorption desulfurization (RADS) process. The bimetallic adsorbents synthesized by a two-step impregnation method were analyzed by a series of characterization methods to evaluate the effect of additional metal on the structural and catalytic properties of the traditional Ni/ZnO adsorbent. Hydrogen temperature-programmed reduction (H2-TPR) results showed that the addition of promoter Fe enhanced the reduction performance of NiO, while W hindered the reduction of NiO. The electron density of Ni was modified following the introduction of Fe and W, as analyzed by X-ray photoelectron spectroscopy (XPS), which weakened the adsorption of π complexation between olefins and Ni. Experimental results showed that the desulfurization performance of Ni–Mo was improved but aggravated the loss of the octane number. Ni–W effectively attenuated the olefin saturation reaction but seriously shortened the breakthrough time. The adsorbent modified by Fe can reduce the saturation reaction of olefins and improve the desulfurization performance. In addition, multicycle regeneration experiments proved the excellent regeneration performance of the adsorbent modified by an appropriate amount of Fe. Therefore, the Ni–Fe bimetallic adsorbent may become a novel adsorbent for reactive adsorption desulfurization, which achieves high desulfurization activity and olefin retention ability to satisfy the requirements of fluid catalytic cracking (FCC) gasoline refining.

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.