Fuel born catalyst

In addition, FBC [21] technology provides constant and continuously fresh ceria-based catalyst to the soot layer. This explains why, unlike many other catalyst-based DPF-regeneration technologies, the ceria-based fuel-borne catalyst is relatively insensitive to fuel-sulfur levels and is able to function with fuel containing over 2,500ppm of sulfur, as demonstrated in marine and stationary applications. However, in the presently described automotive application, the permissible level of sulfur is limited by the sulfur-sensitivity of other components of the complete DPF system. 

The secondary function of the ceria-based fuel-borne catalyst [22] is to ensure, once the soot combustion is initiated, a complete and smooth regeneration avoiding exothermic peaks responsible for DPF aging, potentially leading to DPF breakage (Figure 9-13). This is achieved either by the good dispersion of the catalyst in the... 

With a high level of activity whatever the quality of the fuel (sulfur content), the fuel-borne catalyst allows emission levels lower than the ones requested by the most severe regulations that will be effective in 2007 in the US and 2008 in Europe. 

Hari6, V., Pitois, C., Rocher, L., et al. (2008). Latest Development and Registration of Fuel Borne Catalyst for DPF Regeneration, SAE Technical Paper, 2008-01-0331. 

The preparation of catalyst formulations for soot oxidation follows different approaches. One approach is to increase the number of contact points between the soot particles and the catalysts by using fuel-borne catalyst additives or molten salt catalysts, which can wet the... 

GT operation, a lifetime of the catalyst section of >8000 h must be guaranteed, corresponding to yearly replacement during scheduled inspection of hot combustor parts. Catalyst stability against poisoning by air- and fuel-borne contaminants must therefore also be considered. 

Anode catalysts deal with a lesser overpotential problem, but need to be relatively insensitive to fuel-borne carbon monoxide. 

The most widely used catalyst in the acid electrolyte fuel cell is platinum. The main effort is then to disperse as much as possible this metal to reduce its loading without affecting adversely the electrode performance. An additional factor to be borne in mind in the design of fuel cell electrodes is the ease of their mass production. Since each cell will generate at most 1 V, several hundreds of individual electrodes must be made and assembled to provide practical power outputs. 

A lot of attention has been paid to the electrochemical oxidation of H2 in the context of fuel-cell research [141]. Obviously, materials that adsorb H2 diss-ociatively should be the better catalysts, and this is borne out in practice. The best electrocatalyst is Pt (in acid), as indeed for the reverse reaction (Fig. 5.40), the elementary steps being simply [142] ... 

When fuel contains heavier hydrocarbons than methane, or it is biofuel, or contains alcohols, the feedstock often contains additional compounds such as sulphur and phosphorus, that is, fertiliser impurities. In the petrochemical industry, gas-borne reactive spedes (i.e., sulphur, arsenic, chlorine, mercury, zinc, etc.) or unsaturated hydrocarbons (i.e., acetylene, ethylene, propylene and butylene) may act as contaminating agents (Deshmukh et al, 2007). These impurities cause catalyst deactivation by poisoning. The effect of a poison on an active surface is seen as site blockage or atomic surface structure transformation (Babita et a/., 2011). Therefore, it is important to choose poisoning-resistant catalyst materials. For example, nickel is not the most effective MSR catalyst although it is widely used in industry due to its low market price compared to ruthenium and rhodium. Both Ru and Rh are more effective in MSR and less carbon is formed in these systems, than in the case of Ni. However, due to the cost and availability of precious metals, these are not widely used in industrial applications. 

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