Performance of commercial NiO catalysts in mixed methane reforming

Abstract

The global push towards climate neutrality is leading to an increased demand for sustainable transportation. With the aviation industry having a considerable contribution to global CO2 emissions, sustainable aviation fuels are becoming of bigger interest. One possible pathway is the mixed methane reforming of biomethane to produce syngas, a precursor for the chemical industry, which can be used to produce synthetic fuels. Within this thesis four commercially available catalysts, intended for steam reforming, are tested and compared on their performance in mixed methane reforming and dry reforming. A special focus is placed on the Impact of different reaction conditions on catalyst activity, as well as on the issue of coking, which is limiting the implementation of these reforming methods on an industrial scale. For this all catalysts were tested with two reactant ratios, at temperatures of 800 °C, 900 °C, 950 °C and 1000 °C, as well as pressures of 1 bar, 2.5 bar and 4 bar. In addition, dry reforming experiments at 700 °C and 1 bar are performed. To evaluate the catalyst activity the turnover frequencies for both hydrogen and Carbon monoxide are calculated, along with the syngas ratio and the carbon deposition rate. During mixed reforming experiments it was observed that higher temperatures and increased pressures result in higher turnover frequencies and lower syngas ratios. No carbon deposition was observed. During dry reforming experiments for three out of four catalysts, a decrease in turnover frequencies over the reaction time was observed with a continuous decrease in syngas ratio. For these catalysts coke formation was also observed. The fourth catalyst on the other hand showed no decrease in activity, a constant syngas ratio and no coke formation. Additional TGA-MS analysis was used to analyse the spend catalysts. Showing differences in carbon formation, depending on location within the reactor. Overall it was shown that commercial catalysts for steam reforming can be used in mixed methane reforming.