The report describes a study of wet electrostatic precipitators (WESP's) through laboratory experiments, a field test of a full-scale unit, interviews with manufacturers and users, and a literature survey. Experiments were aimed at determining collection efficiency as a function of particle size at varying current densities and specific collection areas. The results agreed reasonably with those predicted by simulating the experimental conditions with a mathematical model. The feasibility of collecting SO2 and particulate in a WESP was examined. As expected, calculation of ion transport rates indicates that only an insignificant amount of SO2 can be removed by selective ionization of SO2 molecules. Mass transfer calculations indicated that irrigated electrode surfaces would not provide sufficient interfacial area for desired SO2 removal levels. Based on conventional geometry and stainless steel construction, a WESP/scrubber device would be more costly than a scrubber-only system because of high WESP capital costs. The effectiveness of a WESP as a mist eliminator following a scrubber was calculated to be a function of the particle size distribution and the concentration of the mist to be collected. The field test and literature survey showed that WESP's have been used effectively to control fine particle emissions in the aluminum, iron and steel, chemical and petrochemical fields.

Prepared by Southern Research Institute, Birmingham, Ala., under contract no. 68-02-1313, ROAP no. 21ACX-095, program element no. 1AB013. Includes appendices. Includes bibliographical references (pages 171-175, 177-192).