Emissions removal efficiency from diesel gensets using aftermarket PM controls

Abstract

Diesel particulate matter (PM) has been associated with adverse health effects in humans and is classified as a human carcinogen. Additionally, the strongly light absorbing fraction, black carbon (BC), has been identified as an important climate forcer. For these reasons, the effectiveness of aftermarket controls on reducing PM and BC from three stationary diesel gensets (230, 400, and 600 kW) of varying engine displacement (from 8.8 to 27 L) and physical size was investigated. Uncontrolled emissions were compared with emissions controlled with a passive (P-DPF) and active diesel particulate filter (A-DPF) and a diesel oxidation catalyst (DOC). Overall, the DPFs resulted in significant PM mass removal (~80–99 %), while the DOC resulted in statistically insignificant reductions (~0–25 %). Both BC and elemental carbon (EC) removal followed a similar trend, but EC/PM ratios varied from 0 to 0.79 over all test conditions, indicating changes in PM composition with the addition of aftermarket controls or changes in load. Further, the single scattering albedo of PM was slightly decreased from the DPFs compared to the uncontrolled case. Particle number concentrations were also significantly reduced when using DPFs, with a greater than 97 % reduction in particle concentrations with the P-DPF and greater than 82 % reduction with the A-DPF. The DOC exhibited much lower particle reductions, reducing the particle concentration by only 5–35 %, depending upon the genset or load. These results demonstrate that while DPFs are effective at reducing PM and BC emissions, the particle characteristics are altered from those of uncontrolled emissions.