Ship emissions, particularly fine particulate matter (PM2.5), have a negative impact on air quality and pose serious health risks. This study examines emissions from marine diesel engines, which are regulated by the International Maritime Organization (IMO) to reduce their environmental impact. The primary goal is to characterize the ash produced by diesel engines and assess its theoretical impact on diesel particulate filters (DPFs), which are essential for meeting regulatory standards and protecting the environment. The experimental work aims to determine if ash produced rapidly using lubricating oil and a diesel generator could be compared to ash emissions from a marine diesel engine.
Diesel exhaust ash is a non-combustible residue resulting from the combustion of diesel fuel, lubricating oil, and engine wear. The study provides detailed information on diesel particulate matter and diesel exhaust ash, including their formation, size distribution, and chemical composition. It also discusses the function of DPFs and the importance of ash properties for their performance. Various techniques for measuring and characterizing ash are reviewed as a foundation for experimental analysis.
In the experimental part of the study, exhaust ash was generated using a diesel generator running on DMB fuel (a distillate marine fuel blend) mixed with ash-forming lubricating oil. The physical properties and the chemical composition of the exhaust ash were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Additionally, gas emissions, soot levels, and particle number concentration and distribution were measured.
The analysis revealed that the particle number concentration in the exhaust gas from the doped DMB fuel was higher. Morphological studies identified various particle types, including nano-sized fuel particles, spherical lubricating oil particles containing calcium, and agglomerated soot particles. Adding lubricating oil to the fuel reduced soot emissions because the metal compounds in the oil facilitated the combustion of soot particles.
The study concludes that fuel composition affects particulate emissions and their properties. The findings align with previous research and underscore the need for effective exhaust aftertreatment to reduce the environmental and health impacts of diesel emissions. Further research is recommended to explore the long-term effects of ash accumulation on DPFs, especially in conjunction with other aftertreatment systems. The study also highlights the need for more accurate methods to continuously measure ash content in exhaust emissions.