Suchergebnisse

6 figures, 3 tables.-- Supplementary material under CC-BY license https://creativecommons.org/licenses/by/4.0/ ; Fuel reformulation through the use of oxygenated compounds e.g. dimethyl carbonate (DMC) is a potential option both to reduce the harmful soot emissions and to overcome the dependence on fossil fuels since many of them are bio-derived fuels. DMC presents a relative high oxygen content as compared with other additives and suitable characteristics to be used in combustion systems. The different fundamental aspects of the DMC combustion process including its oxidation behavior its tendency to produce soot and the role of the NO presence in the reaction system were studied. Experiments were conducted under well controlled conditions using specifically designed flow reactor systems. Results demonstrated the low tendency of DMC to form soot compared to other oxygenates and its capacity to contribute to NO reduction under specific fuel-rich conditions. Modeling calculations successfully reproduce reasonably well the experimental trends observed and emphasized the sensitivity of the results to the thermodynamic data of DMC and DMC derived species. ; Authors acknowledge the Aragón Government and the European Social Fund, GPT group, and MINECO and FEDER (Project CTQ2015-65226-R) for financial support. Dr. M. Abián acknowledges the MINECO and Instituto de Carboquímica (ICB-CSIC) for the post-doctoral grant awarded (FPDI-2013-16172).

Research in solid-gas heterogeneous catalytic processes is typically aimed toward optimization of catalyst composition to achieve a higher conversion and, especially, a higher selectivity. However, even with the most selective catalysts, an upper limit is found: Above a certain temperature, gas-phase reactions become important and their effects cannot be neglected. Here, we apply a microwave field to a catalyst-support ensemble capable of direct microwave heating (MWH). We have taken extra precautions to ensure that (i) the solid phase is free from significant hot spots and (ii) an accurate estimation of both solid and gas temperatures is obtained. MWH allows operating with a catalyst that is significantly hotter than the surrounding gas, achieving a high conversion on the catalyst while reducing undesired homogeneous reactions. We demonstrate the concept with the CO 2 -mediated oxidative dehydrogenation of isobutane, but it can be applied to any system with significant undesired homogeneous contributions. ; Financial support from the European Research Council Advanced Grant (HECTOR267626), the Regional Government of Aragon (DGA), and the MINECO and FEDER (project CTQ2015-65226) is acknowledged. ; Peer reviewed