DPF Systems for High Sulfur Fuels 2011-01-0605

During the first decade of diesel particle filter development and deployment in cars, trucks, buses and underground sites, DPF regeneration methods were engineered that were compatible with the then prevalent high sulfur content in the fuel ≻ 2000 ppm. The mainly used methods were burners, electrical heaters, replaceable filters and non-precious metal fuel additives. Low sulfur diesel fuel became only available from 1996 in Sweden, 1998 in Switzerland, and after 2000 everywhere in Europe. Thus, the deployment of precious metal catalytic converters was feasible both as original equipment and retrofitting of in-use engines. The so-called CRT particle filters using PGM-catalysis for providing NO₂ for low temperature regeneration became very successful wherever ULSD was available. However, in many applications, e.g., off-road and in the construction industry, diesel engines continued to run on high sulfur fuel and in many emerging countries, even on-road diesel fuel still contains between 1000 and 2000 ppm sulfur. These countries suffer very much from air pollution through increasing diesel particle emissions and the high impact of black carbon particles on human health as well as on the global warming is worrying. Hence, the necessity for modern particle filters that are compatible with high sulfur content of the fuel. In the context of Chinese megalopolis, this paper reports investigation of a fuel which is typical for China (containing ≻ 1000 ppm sulfur) and compares results with European standard diesel fuel. The test objects were two modern SiC particle filters, which were regenerated using different iron-based FBC. The combustion attributes of the soot were investigated by TGA and their EC/OC composition was examined. The results indicate that at the given test conditions the fuel sulfur does not significantly change the filters' physical and chemical properties. Neither the filter particle loading process nor the filter regeneration is noticeably different for the high sulfur test fuel compared to the ultra-low sulfur European fuel. Therefore VERT-verified iron-based FBC-type DPF can be used in countries where ULSD is not yet available.