Correlation between Real Diesel Fouled-EGRc Soot Samples and Soot Surrogates: Reactivity with NO and O ₂ and Chemical-Physical Characterization 2018-01-1269

Soot and NO_x, may react in situ with each other and reduce, thus, their emissions. Therefore, this reaction can be considered as a strategy of elimination of both air pollutants at the same time. In general, it is well established that heterogeneous reactions between soot and the different gases, generally existent in combustion environments, are affected by soot properties. Detailed characterization of soot samples coupled to reactivity studies towards O₂ and NO have been carried out in order to identify the differences and similarities among the kinds of soot studied for understanding in what extent the origin of soot samples is a key parameter on their structure and reactivity. The combined analysis and interpretation of the soot chemical-physical features are essential to correctly interpret and to predict its behavior in the combustion chamber when soot is in contact with the combustion gases at high temperature. Five real diesel soot samples obtained from exhaust gas recirculation heat exchangers (2 from test benches with different experimental conditions and 3 from vehicles) have been analyzed and compared with two commercial carbonaceous materials usually considered as possible soot surrogates (PU and SRM). Possible correlations between real soot samples and model soot samples are of great interest (since it is not easy to obtain large quantities of real soot to work with) and they have been achieved in this work with satisfactory results. Besides, the results obtained from the solid-gas interaction confirm the reduction of both pollutants at the same time in the conditions studied. Further work is required to assess whether this technique can be implemented in actual vehicle strategy.