The Filtration, Oxidation and Pressure Drop Characteristics of a Catalyzed Particulate Filter during Active Regeneration – A 1D Modeling Study

Active regeneration of a catalyzed particulate filter (CPF) is affected by a number of parameters specifically particulate matter loading and inlet temperature. The MTU 1-D 2-Layer CPF model [1] was used to analyze these effects on the pressure drop, oxidation and filtration characteristics of a CPF during active regeneration. In addition, modeling results for post loading experiments were analyzed to understand the difference between loading a clean filter as compared to a partially regenerated filter.

Experimental data obtained with a production Cummins regenerative particulate filter for loading, active regenerations and post loading experiments were used to calibrate the MTU 1-D 2-Layer CPF model. The model predicted results are compared with the experimental data and were analyzed to understand the CPF characteristics during active regeneration at 1.1, 2.2 and 4.1 g/L particulate matter (PM) loading and CPF inlet temperatures of 525, 550 and 600°C. The activation energies for thermal oxidation reported in Chilumukuru et al. [2] were used and confirmed by these modeling results.

The model results showed that the pressure drop during active regeneration at 525, 550 and 600°C CPF inlet temperature is a function of PM loading. The pressure drop across the CPF has a higher rate of decay for higher temperatures. Analysis of model results showed that the peak pressure drop is a function of CPF inlet temperature at the same PM loading. The model results for all experiments targeted to up to 70% PM oxidation showed that the total filtration efficiency across the CPF during active regeneration is over 99%. Model results for post loading showed that the pressure drop across the CPF is lower compared to loading for the same amount of PM present in the CPF. The difference in pressure drop between loading and post loading was correlated to the wall pressure drop which is directly proportional to the mass of PM in the wall.