Submicrometer PM Removal of an ESP Combined With a Metallic Foam Filter for Large Volumetric Diesel Engines

An electrostatic diesel particulate matter (PM) filtration device was tested using 4000-cm³ diesel engines operating at standard [European Stationary Cycle 13 and European Transient Cycle] conditions, at temperatures between 100 °C and 500 °C and gas velocities of up to 30 m/s. The device consisted of an edge-to-cylinder-type electrostatic precipitator (ESP) and a metallic foam filter. To minimize the volume of the foam filter and reduce pressure drop through the filtration device, the thickness of the layer of foam filter was reduced from 34.5 to 11.5 mm. PM emissions with the filtration device, using a foam sheet thickness of 11.5 mm, were less than 0.01 g/kWh, which met the diesel PM standard given in Euro 6 regulations. Emissions using only a foam filter with 11.5-mm layers were over 0.03 g/kWh. The pressure drop of the device with 11.5-mm foam sheets was 25% of that using 34.5-mm layers. A foam filter coated with Pt catalysts was tested at temperatures ranging from 300 °C to 400 °C, and approximately, 12-g PMs were burned out through natural regeneration.