Ultradeep Adsorption−Desulfurization of Gasoline with Ni/Al−SiO2 Material Catalytically Facilitated by Ethanol

Abstract

Adsorptive desulfurization of low-sulfur (22 ppmw) gasoline on solids in a liquid-full (no hydrogen) fixed bed was conducted at 503 K. Addition of 3 wt % ethanol to gasoline increased significantly the adsorption rate of sulfur-containing hydrocarbons on Ni/Al−SiO2 and its sulfur capacity, leading to <0.5 ppmw residual sulfur with a sulfur capacity of 2 wt % (mass of sulfur per mass of sorbent). Three potential routes for improving desulfurization performance of Ni sorbent in the presence of ethanol and its decomposition products containing CO and hydrogen were considered: (i) formation of nickel carbide (Ni3C) phase with reactivity toward S-organic compounds higher than that of metallic nickel, (ii) reduction of carbon deposits in the presence of hydrogen, and (iii) formation of nickel sulfide nanoparticles in the presence of H2/H2S vs adsorbed sulfur/sulfur organics that block the surface of metallic nickel in the absence of EtOH (hydrogen). Catalyst characterization data (N2 adsorption, XRD, EDX, HRTEM...