EFFECT OF THE SOOT CAKE THICKNESS ON THE REGENERATION PERFORMANCE OF A CATALYTIC DIESEL PARTICULATE FILTER

In this work, the effect of the soot-catalyst contact on the regeneration performance of a diesel particulate filter (DPF) wash-coated with nanometric ceria particles was investigated. The catalyst was highly dispersed inside the filter walls. Furthermore, its load was suitably chosen to avoid major changes in pore size distribution of the bare filter. Different amounts of soot were loaded into the filter, thus varying the conditions of soot-catalyst contact. At the lowest soot load explored, the deep penetration of soot particles into the macro-pores of the filter walls and the consequent good contact with the catalyst particles result in a large fraction of soot burned via catalytic path at low temperatures. At the highest soot load explored, in addition to the soot particles trapped inside the macro-pores, a rather thick soot cake layer accumulates on top of the catalytic walls of the filter. The soot cake is oxidized via thermal path at high temperatures, being substantially segregated from the catalyst.