Oxidative Reactivity of Soot Particles Generated from the Combustion of Conventional Diesel, HVO and OME Collected in Particle Filter Structures

The reduction of CO₂ emissions in transport and power generation is currently a key challenge. One particular opportunity of CO₂ reduction is the introduction of low CO₂ or even CO₂ neutral fuels. The combustion characteristics of such fuels are different and require engine settings modification. In addition, emissions characteristics differ significantly among different fuels. In the present study a one cylinder diesel engine was operated with conventional diesel, hydrogenated vegetable oil (HVO) and polyoxymethyl dimethyl ether (OME) as well as a series of blends. Particle filter segments were positioned in the exhaust of the engine and loaded with particles originating from the combustion of these fuels. The filter segments have been regenerated individually in a specifically designed and developed controlled temperature soot oxidation apparatus. In this setup, the temperature of the segments during soot oxidation was controlled while the mass of the oxidized soot was monitored by gas analysis and species balances as well as gravimetrically. The computation of soot oxidation rates based on the measured evolution of gas composition in time at the segment exit has been performed. The influence of the soot origin on the regeneration energy is elaborated. A further focus lies on the influence of the soot particle size on the activation energy. In hindsight to this, particle filter segments were loaded under different engine operating conditions, for differing particle sizes. The regeneration of these segments show the impact of fine particles on the filter regeneration temperature and duration. The energy demand for the real-world regeneration of diesel particle filters (DPFs) is also evaluated.