SYNTHESIS, CHARACTERIZATION AND RIG TESTS OF SUPPORTED FE AND CO-BASED NANOSTRUCTURED CATALYSTS ACTIVE IN THE THERMOCHEMICAL BTL/CTL/GTL-FT PROCESSES

During this PhD project different Fe and Co-based catalysts active in the FT reaction have been synthesized, characterized and tested, in particular: 1- An impregnated synthesized Fe-based catalyst supported on SiO2 and promoted with K and Cu (30 %wt of Fe, 2 %wt of K and 3.75 %wt of Cu) named Fe30K2Cu3.75. In particular, potassium improves CO ad-sorption while Cu promotes the reduction of the iron oxides species. The loading of active metal and promoters have been already determined elsewhere in recent studies. 2- Three different Co-based catalysts synthesized by flame spray pyrolysis (FSP) and supported on SiO2, and eventually promoted with Ru (5 %wt of Co; 10 %wt of Co; 10 %wt of Co and 0.4 %wt of Ru). The catalysts are named as 5Co, 10Co and 10Co-0.4Ru. FSP technique allows to obtain single or mixed metal oxides characterized by a high surface area and high thermal stability due to the instantaneous dispersion, vaporization and flame-decomposition (pyrolysis) of an organic solution composed by the precursors of the catalyst. 3- Three different Fe-based samples supported on SiO2 and promoted with K and Cu, prepared with the use of ultrasound (US) (10 %wt of Fe; 30 %wt of Fe; 30 %wt of Fe, 2 %wt of K and 3.75 %wt of Cu). Cata-lysts are named as Fe10US, Fe30US and Fe30K2Cu3.75US. In particular US allows to synthesize materials with better morphological properties with respect to traditional impregnated samples. Fe30K2Cu3.75 (1) sample is active for the FT conversion even if syngas with a H2/CO ratio similar to the ratio of bio-syngas (H2/CO= 1) is fed to the reactor. The catalyst presents a satisfactory stability as a function of TOS and selec-tivity toward the reaction products remains essentially unchanged at different syngas ratios at the same temperature tested. The developed kinetic model is in fully agreement with the ones fundable in the recent literature for iron-based catalysts tested in fixed bed FT reactor. 10Co and 10Co-0.4Ru (2) samples are active in the FT synthesis in the range of temperatures tested with a H2/CO= 2 syngas fed to the reactor. 5Co did not show any activity to FT reaction in the experimental condi-tion tested. 10Co sample showed a great stability in function of TOS at T= 250 °C, reactants conversion and selectivity towards the reaction products were stable for the whole duration of the durability test (TOS= 200 h). The addition of 0.4 %wt of Ru improved significantly catalyst activity in terms of reactant conversion. All the US synthesized samples (3) are suitable catalysts for the FT reaction at the different tested conditions and with a H2/CO ratio equal to 2. Both Fe10US and Fe30US catalysts showed excellent stability as a function of TOS at all the tested reaction temperatures. The sonochemically prepared catalysts showed good results in terms of selectivity toward the reaction products.