Simulating Real World Soot-Catalyst Contact Conditions for Lab-Scale Catalytic Soot Oxidation Studies

Abstract

In diesel soot oxidation studies, both well-defined model soot and a reliable means to simulate realistic contact conditions with catalysts are crucial. This study is the first attempt in the field to establish a lab-scale continuous flame soot deposition method in simulating the “contact condition” of soot and a structured diesel particulate filter (DPF) catalyst. The properties of this flame soot were examined by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM) for structure analysis, Brunauer-Emmett-Teller (BET) for surface area analysis, and thermogravimetric analysis (TGA) for reactivity and kinetics analysis. For validation purposes, catalytic oxidation of Tiki® soot using the simulated contact condition was conducted to compare with the diesel particulates collected from a real diesel engine exhaust system. It was found that the flame soot is more uniform and controllable than similar samples of collected diesel particulates. The change in T50 due to the presence of the catalyst is very similar in both cases, implying that the flame deposit method is able to produce comparably realistic contact conditions to that resulting from the real exhaust system. Comparing against the expensive engine testing, this novel method allows researchers to quickly set up a procedure in the laboratory scale to reveal the catalytic soot oxidation properties in a comparable loose contact condition.

In-Situ Fabrication of g-C3N4/ZnO Nanocomposites for Photocatalytic Degradation of Methylene Blue: Synthesis Procedure Does Matter

“…To find out the major active species for the photocatalytic oxidation, several scavengers were added in the photocatalytic system individually to trap and remove corresponding active species. It was reported that ammonium oxalate (AO), isopropanol (IPA), and N 2 could act as effective scavengers to holes (h + ), hydroxyl radical (●OH), and superoxide radical (●O 2 − ) [ 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. As shown in Figure 8 , the photodegradation activity of the g-C 3 N 4 /ZnO (0.1:1 CN) sample had a dramatic decrease with the addition of AO and N 2 under light irradiation, suggesting that both holes and ●O 2 − are the main oxidative species in a MB degradation reaction.…”

Understanding of Soot Removal Mechanism over DeNOx-Catalysts as Passive Converters

“…Particulate matter is mainly composed of carbon with some inorganic materials and adsorbed hydrocarbons, SO x , and water, and its composition influences the catalytic activity, as well as the synthesis conditions . The reduction of this type of species is not easy but completely necessary since the small diameter makes them dangerous for human health . Although the diesel oxidation catalyst (DOC) is able to reduce the amount of particulate matter, the almost complete soot combustion is carried out over the diesel particulate filter (DPF). , This monolithic system consists of small axial parallel channels through which the gas can flow, whereas the particles are retained onto the surface and in the porosity of the channel walls. − As a consequence, the pressure loss increases, and the regeneration by increasing the temperature is required.…”

Improved Hydrothermal Stability in Glass Diesel Soot Oxidation Catalysts

“…Any activity degradation, whether it is due to hydrothermal surface modification or a loss of active potassium, will be detected as an increase in the soot oxidation temperature. To closely mimic the real conditions experienced by a DPF on a diesel engine, "loose" soot contact was achieved by a flame soot deposition technique as described elsewhere [31,79]. Klearol ® white mineral oil with~1 ppm sulfur was used as the fuel oil for soot generation.…”