Capture of fine particles on charged moving spheres, a new electrostatic precipitator

A study of a novel electrostatic approach to fine-particle collection was carried out on a specially designed test apparatus. Copper spheres were first electrostatically and then dynamically suspended between two horizontal parallel plates using an applied DC electric field. The sizes studied were 74-88, 102-25, and 125-47 mu m. The charged spheres, which were larger by a factor of 10 to 100 than the dust captured (mean diameter 2.4 mu m), were then electrostatically propelled into an adjacent duct where they scrubbed a crossflowing dust-laden gas by the processes of impaction and electrostatic attraction. The total collection efficiency of the device and the target collection efficiency of the charged copper spheres were studied. Both were found to increase with the charging electric field strength, the target particle diameter, and the duct air velocity. This research suggests that electrostatic precipitation based on the scrubbing action of charged solid particles is possible, and that total collection efficiencies of up to 99% cleanup (or greater) should be attainable. Fly-ash collection performance exceeding that based on theory with regard to the particle target efficiency was observed.<>