Control of Respirable Particulate Matter from Flue Gases

41179 Ion Physics Corporation Electrostatic precipitation is used extensively to control the emission of particulate matter from oil or coal burning power stations. However, an unsolved problem concerns the efficient removal of fine particulates (particles of 5 ¿m in diameter and below) from the flue gas stream. Particles of this size are important because the human respiratory system does not effectively filter them and they pass readily into the throat and lungs. The rate at which particles can be removed from the gas stream depends on their average velocity towards the collecting plates. This velocity, commonly referred to as migration velocity, is strongly dependent on particle size. Smaller particles, because of their much smaller charge, have a substantially lower migration velocity. One way to overcome this problem is to agglomerate particles, thus forming larger and, consequently, easier to collect particles. Particles will agglomerate by finding each other simply through random thermal motion. Unfortunately, this process is too slow to be of practical value in electrostatic precipitators. This project will develop a variant of bipolar agglomeration, where one fraction of the entrained particulates are charged with one polarity and the remaining fraction to the opposite polarity. Commercial Applications and Other Benefits as described by the awardee: Successful completion should show high removal rates of fine particles from flue gas with reasonable time and volume requirements. The process could provide a cost effective means for new and existing plants to control fine particulates.