Catalytic Decomposition of N2O at Low Temperature by Reduced Cobalt Oxides.

Various forms of cobalt oxide (Co3O4 and C0203) were subsequently prepared and tested for decomposition of N2O at low temperature in a fix bed differential reactor at steady state conditions. These different types of oxides were prepared by precipitation method (PM) and by calcination of commercially available CoCO3. Commercially available cobalt oxides C03O4 and C02O3 were also tested for N2O decomposition at different temperatures. All types of prepared and commercially available cobalt oxide were found inactive for N2O decomposition in the presence of oxygen at temperature less than 300 degrees C. Similar unsatisfactory results were found at low temperature N2O decomposition after impregnation of alkali metal (10% Na) and alkaline earth metal (10% Ba) over Co3O4. These catalysts were then reduced under reduction media (H2 gas). It was found that after reduction cobalt oxide catalysts became active for N2O decomposition for short time in the presence of oxygen at low temperature. The reduced form of Co3O4 catalyst showed enormous efficiency i.e., 98% at temperature (300 degrees C) under the same conditions. From results it seems that Co3O4 itself is not active for N2O decomposition but its reduced form is highly active for this reaction due to oxidation state change of C03O4 during reduction process.

Long-term operation of biomass-to-liquid systems coupled to gasification and Fischer-Tropsch processes for biofuel production.

Long-term operation of the biomass-to-liquid (BTL) process was conducted with a focus on the production of bio-syngas that satisfies the purity standards for the Fischer-Tropsch (FT) process. The integrated BTL system consisted of a bubbling fluidized bed (BFB) gasifier (20 kW(th)), gas cleaning unit, syngas compression unit, acid gas removing unit, and an FT reactor. Since the raw syngas from the gasifier contains different types of contaminants, such as particulates, condensable tars, and acid gases, which can cause various mechanical problems or deactivate the FT catalyst, the syngas was purified by passing through cyclones, a gravitational dust collector, a two-stage wet scrubber (packing-type), and a methanol absorption tower. The integrated system was operated for 500 h over several runs, and stable operating conditions for each component were achieved. The cleaned syngas contained no sulfur compounds (under 1 ppmV) and satisfied the requirements for the FT process.