Effect of Biodiesel impurities (K, Na, P) on non-catalytic and catalytic activities of Diesel soot in model DPF regeneration conditions

Abstract(#br)The impact of Biodiesel impurities (Na, K and P) on the non-catalytic and catalytic reactivity of Diesel soot was evaluated under model DPF (Diesel Particulate Filter) regeneration conditions. Temperature-programmed oxidation (TPO) measurements confirmed that Na and K depositing into soot or on the surface of the catalyst enhanced the oxidative reactivity of soot under both O 2 and NO x + O 2 and Na-doped samples showed better results. However, the presence of P inhibited the non-catalytic and catalytic reactivity. These findings can be mainly attributed to the changes in nanostructure and surface chemical properties of the doped samples, characterized by Raman, high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), H 2 temperature-programmed reduction (H 2 -TPR) and NO temperature-programmed oxidation (NO-TPO). The result of this characterization evidenced that the presence of Na and K increased structural defects of soot and reduction ability of the catalyst. Moreover, Na-/K-doped catalysts presented higher oxidizing ability of NO into NO 2 , whereas the opposite trend was observed for the P-containing catalysts. In addition, higher structural disorder of Na-doped soot and higher alkali metal content on the surface of Na-doped catalyst might lead to enhanced reactivity in comparison to K-doped soot and catalyst

Influence of the Sodium Impregnation Solvent on the Deactivation of Cu/FER-Exchanged Zeolites Dedicated to the SCR of NOx with NH3

The effect of the sodium addition mode was investigated on model Cu/FER selective catalytic reduction (SCR) catalysts with two copper loadings (2.8 wt. % and 6.1 wt. %) in order to compare samples with or without over-exchanged copper. Na was added by wet-impregnation using two solvents: water or ethanol. Catalysts were evaluated in Standard and Fast-SCR conditions, as well as in NO and NH3 oxidation. They were characterized by H2-TPR, NO and NH3 adsorption monitored by FT-IR. As expected, whatever the copper loading, ammonia adsorption capacity was decreased by Na additions. Interestingly, characterizations also showed that Na impregnation in water favors the migration of the Cu-exchanged species, leading to the formation of CuO extra-framework compounds. Consequently, for both copper loadings, Na impregnation in water led to a stronger catalyst deactivation than impregnation in ethanol. Finally, the NOx conversion at low temperature (250 °C) appeared mainly affected by the loss in NH3 adsorption capacity whereas the deNOx deactivation at high temperature (500 °C) was rather governed by the decrease in the exchanged copper ratio, which also induced a partial inhibition of NO and NH3 oxidation behaviors

Structure-reactivity study of model and Biodiesel soot in model DPF regeneration conditions

International audienc

High-throughput approach to the catalytic combustion of diesel soot II: Screening of oxide-based catalysts

International audienc

Impacts of oxygenated compounds concentration on sooting propensities and soot oxidative reactivity: Application to Diesel and Biodiesel surrogates

International audienceThe aim of this paper is to evaluate the effect of the oxygenated compounds concentration on sooting propensities of Diesel and Biodiesel surrogates and to investigate the oxidative reactivity of soot obtained by combustion of these surrogates using an atmospheric axisymmetric co-flow diffusion flame burner. Methyl decanoate (MD) concentrations from 3 to 30 % (in mole %) are added to a Diesel surrogate made up of a binary mixture of 70 % of n-decane and 30 % of α-methylnaphthalene (α-MN). The sooting propensities of these mixtures are estimated through the Yield Sooting Indices (YSIs) in methane diffusion flames doped with 35,000 ppm of surrogate vapors. The characteristics of the soot volume fraction are extracted using the light extinction method (LEM). Additionally, soot generated from the combustion of the model Diesel and Biodiesel fuels were collected, sampled and characterized using physico-chemical techniques. MD addition is found to reduce sooting tendencies. This decrease is more pronounced when the concentration of oxygenate additives 2 increases. On another side, the oxidative reactivity of soot generated from the diffusion flame burner is found to decrease when the Biodiesel percentage increases. Furthermore, soot generated from the combustion of Diesel and Biodiesel surrogates exhibited different behaviors. Biodiesel-derived soot particles were smaller and less reactive than Diesel-derived ones, the latter displaying less ordered graphite-like structures and higher amorphous carbon concentration