Study of the Influence of DPF Regeneration Conditions on the Oxidation Characteristics of Particulate Matter in Biodiesel Combustion

After a diesel engine is fueled with biodiesel, the morphology and oxidation activity of particulate matter will change, which will affect the performance and regeneration effect of the diesel particle filter (DPF). This article measured the CO2 concentration and regeneration efficiency during the DPF regeneration process under different biodiesel blending ratios, carbon load, heating rates, gas flow rates, and ash content by building a regeneration burner test bench and explored the influence of different regeneration conditions on the oxidation characteristics of biodiesel particulate matter. The results showed that with the increase of biodiesel blending ratio, carbon load, heating rate, and ash content, the CO2 concentration increased and the regeneration efficiency was improved. Notably, when using pure biodiesel, the regeneration efficiency can reach up to 94%. Thermogravimetric analysis showed that under different regeneration conditions, the particle oxidation activity did not change significantly when the regeneration temperature was between 300°C and 400°C, but the activity changed significantly at 500°C. Increasing carbon loading, heating rate, gas flow rate, and ash content to some extent helped improve oxidation activity. Scanning electron microscopy analysis revealed that an increase in biodiesel blending ratio leads to a decrease in particle size and an increase in quantity, and the particles become finer during oxidation, with an increase in porosity and internal voids.