Mining Publication: Effects of Sintered Metal Diesel Particulate Filter System on Diesel Aerosols and Nitric Oxides in Mine Air

• Aerosols
• Diesel exhaust
• Diesel particulate filters
• Nitrogen dioxide
• Particle count
• Particle size distribution

This study was conducted to establish the effects of a diesel particulate filter (DPF) system with sintered metal substrate on the concentrations and size distributions of nano and ultrafine aerosols and concentrations of nitric oxides in underground mine air. The study focused on the formation and transformation of nucleation mode particles in mine air under prevailing test conditions. Experimental work was conducted in the NIOSH Diesel Laboratory at the Lake Lynn Laboratory experimental mine, a facility developed to allow evaluation of control technologies directly in underground conditions. The DPF system was examined for four repeatable steady-state engine modes using a naturally aspirated mechanically controlled Isuzu C240 diesel engine fueled with ultralow sulfur fuel. The engine coupled to an eddy-current dynamometer was operated in the underground drift with tightly controlled ventilation. Measurements upwind and downwind of the exhaust system discharge were used to quantify the effects of the DPF system on the mine air. A baseline was established using a standard muffler. The study showed that sintered metal DPF systems reduced the total mass of aerosols in the mine air by more than ten-fold when compared to a muffler. The nucleation mode aerosols (₅₀d_em<40 nm) in mine air were found to be strongly influenced by engine operating mode. The concentration of nucleation aerosols was significantly higher for high-load modes than low-load modes. The muffler and dpf system resulted in comparable total nitrogen oxides (NOx) concentrations. However, the nitrogen dioxide (NO₂) fraction of the total NO_x was found to be substantially higher for both systems for low-load modes than for highload modes.