Demand-reduction programs

As part of its systems analysis, the DOE should map out and evaluate a transition plan consistent with developing the infrastructure and hydrogen resources necessary to support the committee s hydrogen vehicle penetration scenario or another similar demand scenario. The DOE should estimate what levels of investment over time are required—and in which program and project areas—in order to achieve a significant reduction in carbon dioxide emissions from passenger vehicles by midcentury. 

Initially, fuel sulfur was regulated to reduce emissions of the oxides of sulfur, which contribute to acid rain, ozone, and smog. The recent and stricter round of sulfur specifications, however, are an effort to reduce automobile emissions of the oxides of nitrogen (NO c) and particulate matter (PM). For example, the 15 ppmw diesel sulfur limit follows from the USEPA s parallel program of rule making that seeks to reduce automobile NO and PM emissions by 95% and 90%, respectively, by 2007. Automobile manufacturers are demanding ultra-low-sulfur fuels because only then would their advanced, sulfur-sensitive after-treatment technologies achieve such drastic reductions in NO and PM emissions. 

The development of new catalysts for the storage and reduction of NO, from lean-burn engines is a challenge to meet the demands of the Euro IV norm in 2005. The new catalyst systems should also be able to adsorb NO, already at comparable low temperature and desorb it at high temperature. Cu and Ba exchanged zeolites of various types (Y, MOR, MFI, L, CHA) and their ability to adsorb NOx isothermally from a dry feed and to desorb it under temperature-programmed conditions (55-600°C) are described. Their NOx adsorption /desorption properties under wet conditions are compared. Furthermore, a zeolite material modified by manganese oxide is developed which is able to adsorb NOx from a wet feed already at temperatures as low as 120 °C and desorb it above 350°C. 

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