电袋除尘器颗粒物脱除理论和实验研究进展

Progress of Theoretical and Experimental Study of Particle Removal by Hybrid Electrostatic Precipitators

电袋除尘器不需要二次除尘设备即可达到颗粒物超低排放标准,是燃煤电厂颗粒物超低排放的重要选择之一。从实验和理论分析两个方面综述了电袋除尘器的研究进展,滤料过滤经历清洁滤料过滤期和粉尘层过滤期,颗粒在外加电场作用下产生极化现象且表面带有同种电荷,极化现象促使纤维表面形成均匀、稳定且具有较强颗粒捕集能力的长颗粒链,能够缩短清洁滤料过滤期;库伦斥力则使滤料表面的颗粒形成疏松结构的粉尘层,降低过滤压降、提高过滤效率且易于清灰。本文从颗粒电荷衰减角度出发进行了电袋复合除尘器和先进混合电袋除尘器的协同性分析,说明强化电除尘区和袋除尘区颗粒物协同脱除特性的耦合电袋除尘器将是未来发展的主要方向之一。

Hybrid electrostatic precipitators is a major device for removing the particulate in coal-fired power plant because it has advantages of high reliability, compact size, saving space and low operating cost. The particulate matter emissions can be less than the ultra-low emission standards by the hybrid electrostatic precipitator without the additional dust removal equipment, it presents the application status and the research progress on the experimental and technology of the hybrid electrostatic precipitators. Two states of filtration without and with the dust cake occurs in filtration process. Particle exposed to electric fields acquires charge along with polarization. Particle deposits on the fiber as uniform, stable dendrites because of polarization. The dendrites have excellent performance to capture the charging particle, shortening the time of free-cake state. The porous cake formed due to the Coulomb force, has advantages of the low filtration pressure, high collection efficiency and easy dust cleaning. The synergetic removal of particles for the COHPAC and the AHPC is analyzed by means of the charge decay. The hybrid electrostatic precipitator combined the COHPAC and the AHPC is prospective to enhance the synergetic removal of particles.