Survey and Evaluation of Modern Electrostatic Concepts Applied to High-Resistivity Fly Ash

摘要

The ineffectiveness of conventional electrostatic precipitators on high resistivity fly ash has different, though interrelated, causes. Voltages high enough to generate corona at the discharge electrode also generate back corona on the deposited dust layer. Removal of the layer results in reentrainment losses. Reduction of voltage to suppress back corona reduces precipitation effectiveness. All of the surveyed concepts attempt to deal with one or more of these problems; most but none will address all of the deficiencies. A versatile multiple-concept pilot precipitator would allow GFETC to develop the optimum combination of novel concepts. Acurex is recommending a precipitator with component interchangeability in three sections: (1) the main precipitator section (one or more cells) should be designed to accept either conventional electrodes or a few tri-electrode configurations. Versatile pulse-charged power supplies will be needed to accommodate the various electrode configurations. The best method of suppressing back-corona in the precipitator itself can thus be developed; (2) a precharger section should be installed ahead of the main precipitator to optimize precharger design; and (3) a downstream collector section would test the effectiveness of concepts which lend themselves to effective collection of low-load, high-resistivity, small particles. These include wet precipitators, fabric filters, and bed filters. The separation of functions will allow more effective particle charging in the first section, collection of most of the particulate without reverse ionization in the main section, and polishing of the remaining fine and reentrained particulate in a suitable downstream collector. (ERA citation 06:028616)