Plasma-Enhanced Electrostatic Precipitator (ESP) with Self-Cleaning Electrode for Scalable Remediation of Particulate Matter in Large Diesel Engines

Abstract We have demonstrated a fundamentally new pollution control device that integrates a plasma-enhanced electrostatic precipitator (PE-ESP) with a self-cleaning electrode. In the PE-ESP, high-voltage (20 kV) nanosecond (20 ns) pulses generate a transient plasma that produces ion densities approximately 6 orders of magnitude higher than those created by a conventional DC corona. This plasma enhancement increases the particle charging efficiency and allows electrostatic precipitators to be designed much more compactly, making them suitable for mobile sources. Using the PE-ESP, we were able to remove more than 90% of diesel particulate matter while consuming 1% of the available engine power. A key element of this innovation is the soot-collecting electrode, which consists of a highly porous stainless-steel material that can be electrically regenerated using Joule heating to burn off accumulated soot, converting it to CO2. This self-cleaning soot-collecting electrode has been tested through four accumulation–regeneration cycles, demonstrating more than 200 h of reliable operation while maintaining removal efficiencies above 89%. This approach addresses the main challenges associated with conventional emission-control technologies. For example, diesel particulate filters (DPFs) achieve high removal efficiency but create significant engine backpressure, which becomes problematic for large diesel engines. Electrostatic precipitators (ESPs) typically avoid flow restriction, but have historically been too large for mobile sources or high-power engines such as those used in marine vessels or locomotives. We believe this system is the first of its kind and is scalable to large diesel engines in the one-megawatt class and beyond, where no acceptable pollution-remediation solutions currently exist.