Catalytic conversion of glycerol to gasoline-range alkyl-aromatics has been investigated on a series of zeolites (HZSM-5, HY, Mordenite, and HZSM-22) at 300-400 °C and atmospheric pressure or 2 MPa. Although propenal (acrolein) is the major primary glycerol dehydration product over all zeolites, the pore structure of the zeolite plays a significant role on the final product distribution.The major products over one-dimensional zeolites Mordenite and HZSM-22 are oxygenates (propenal, acetol, and heavy oxygenates) without aromatic formation. HZSM-22 is suitable for the production of acrolein with 86% yield at 100% glycerol conversion. However, it is found that glycerol can be converted to high yields of alkyl-aromatics, mainly C 8 -C 10 over three-dimensional HY and HZSM-5. A longer contact time, higher temperatures, and higher pressures favor the formation of aromatics, with a maximum yield of 60% over HZSM-5. A two-bed configuration with a deoxygenation/hydrogenation catalyst (Pd/ZnO) as the first bed and HZSM-5 as the second bed can further increase the alkyl-aromatic yield. The mono-functional oxygenates produced by the first bed were oligomerized and aromatized into gasoline-range alkyl-aromatics over the second bed.
Na promoted Pt/TiO 2 catalysts have been studied under high severity, near equilibrium, conditions for use as a single stage WGS catalyst. Addition of 3 wt% Na to a 1 wt% Pt/TiO 2 catalyst has been found to improve water gas shift activity significantly compared to Pt/TiO 2 , Pt/CeO 2 , and Pt-Re/TiO 2 catalysts. This catalyst is stable when the reaction temperature is higher than 250°C. Deactivation occurred when the reaction temperature was lower than 250°C, however, returning the temperature to higher than 250°C fully recovered activity. TEM observations revealed that addition of Na inhibited Pt particle sintering. These results suggest that Na promoted Pt/TiO 2 is a promising single stage water gas shift catalyst for small scale hydrogen production.
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