Agglomeration of diesel particles by an electrostatic agglomerator under positive DC voltage: Experimental study

We propose characterizing a new geometry of electrostatic agglomerator using particles produced by a diesel engine. The geometry consists of a positive DC voltage wire to cylinder electrostatic precipitator with a porous cathode. The end of the device is closed, which enables all the treated gas to pass through the filtering cathode. Owing to its very small storage surface, the cathode acts like a simple agglomerator. We demonstrate that this agglomerator is sufficiently effective for the re-entrained particles not to be measurable with an electrical low pressure impactor (ELPI), which means that they are both very few in number and largely micronic. The system can function with very short residence times, comparable with the charging times of the treated particles. Energy densities of about 1 J/l are used to achieve a number reduction exceeding 90% on the submicron fraction of particles. It seems that the nature of the cathode has very little influence on particle number decrease. Owing to its compactness, this process displays good potential for the treatment of diesel particles.