(630d) Sulfur Selectivity of Ag/TiO2 Sorbents and the Effects of Fuel Chemistry

Adsorptive desulfurization provides a viable alternative to producing low sulfur fuels from conventional sources such as diesel, gasoline and jet fuel. Such feeds are a prerequisite for the operation of most reformer catalysts as well as fuel cells. Silver supported on TiO2 demonstrated high capacity for sulfur in liquid fuels. For JP5 with a total sulfur concentration of 1172ppmw, this adsorbent demonstrated an 8-10mg/g sulfur capacity. The sorbent was also thermally regenerable over multiple cycles. Sulfur capacity was observed to vary with varying fuel chemistry. Variation in sulfur capacity as a result of the presence of sulfur-free hydrocarbons and polyaromatic sulfur heterocycles (PASH) were investigated. Sulfur affinity was affected by the structure of the PASHs. Capacity was observed to improve with the number of aromatic rings while decreasing due to the presence of alkyl side chains. Sulfur-free aromatics were observed to reduce the sulfur capacity of the sorbent by 75%. The effect of additives such as oxygenates, antioxidants and metal deactivators were also studied. Adsorption isotherms were determined from equilibrium studies. The effect of various fuel components on the isotherms was also established.