Development of the on-board dry DeSOx filter for diesel exhaust

NO_x emitted from diesel is one of the main air pollutants for most countries. To reduce the emission of NO_x could promote to diffuse diesel vehicles. A NO_x storage/reduction (NSR) catalyst has been developed for the diesels. The catalyst for NSR is strongly poisoned by sulfur. We have found good reaction of CaCO3 with sulfur dioxide by using a thermogravimetry. We obtained desulfurization breakthrough characteristic for the sample of the CaCO₃ which is washcoated on the monolith. As a result, this sample which has specific surface area, of 100 m²/g, absorbed SO₂ about 0.43 ~ 0.45 g−_SO2/g−_CaCO3. In this experimental condition, The conversion of the sulfate does not depend on the amount of the supported CaCO₃. The absorption efficiency of these samples were more than 99.4%. According to this result, it was found that the necessary amount of the absorbent was supposed to be 0.538 kg or 2.1 L for 100,000 km running.