Diesel particulate abatement via catalytic traps

This paper concerns the development of catalytic traps for diesel particulate removal from the exhaust gases of light-duty vehicles. The studied traps were realised with ceramic (ZTA and mullite) foam structure, on which two different kinds of catalysts, one based on caesium metavanadates and the other on pyrovanadates, were deposited. Catalyst activity was checked through simple TPO experiments, whereas the performance of catalytic trap prototypes was tested in a pilot plant, where a soot laden gas flow was produced by acetylene combustion. The traps activated through ternary Cs4V2O7+AgCl+CsCl catalyst allowed one to burn out catalytically the soot filtered, thereby keeping pressure drop throughout the trap at acceptable levels for vehicle applications (i.e. below 100 mm H2O). This was achieved at about 370°C, a temperature close to the temperature range of the newest diesel passenger cars (180–350°C). A mathematical model has been assembled and validated by the data obtained with the pilot plant.