Development of sulfur tolerant catalysts for the synthesis of high quality transportation fuels

In this paper, results concerning the development of sulfur tolerant catalysts for Fischer–Tropsch synthesis (FTS), C2+ alcohol synthesis, methanol and/or DME synthesis are presented. In the FTS reaction on Fe using H2-rich syngas such as the biomass-derived syngas, the composition of catalyst pretreatment gas and the addition of MnO on Fe had strong impacts on its sulfur resistance as well as activity. Especially the Fe/MnO catalyst pretreated with CO showed a much lower deactivation rate and a higher FTS activity than an Fe/Cu/K catalyst in the presence of H2S. For C2+ alcohol synthesis a novel preparation method was developed for a highly active MoS2-based catalyst that is well known as the sulfur tolerant catalyst. Besides some metal sulfides were found to show higher CO hydrogenation activities than MoS2. In particular, both Rh and Pd sulfides were active and selective for the methanol synthesis. Modified Pd sulfide catalyst, i.e. sulfided Ca/Pd/SiO2, showed an activity that was about 60% of that of a Cu/ZnO/Al2O3 catalyst in the absence of H2S. This catalyst preserved 35% of the initial activity even in the presence of H2S. The sulfided Ca/Pd/SiO2 mixed with γ-Al2O3 was also available for in situ DME synthesis in the presence of H2S.