| Summary: | 碩士 === 國立臺北科技大學 === 環境工程與管理研究所 === 105 === Electrostatic collection is one of the common methods to collect nanoparticle . The major ways for particle charging include field charging and diffusion charging. Diffusion charging can avoid the direct contact between charging electrode and VOC in treated waste air. Therefore, this research designed a diffusion charger and let the air flow though the charger to generate high concentration ions for particle charging. The factors which can influence particle charging contain ion concentration, particle diameter, and charging time. This research investigated the charge distribution of different particle diameter at various carry gas rate and voltage of diffusion charger. Finally, charged particles stream into flat-plate Electrostatic precipitator to investigate particle penetration at different carry gas rate and voltage.
The experiment results indicated that particle charging efficiency increased with increasing air flow rate and corona voltage of unipolar diffusion charger, The best charging efficiency occur when the corona voltage and air flow rate is 3.3 Kv and 3 lpm, respectively. Moreover, 50 nm particle carries 3 elementary charge with ratio of 36.7%, and 100 nm particle carries 6 elementary charge with ratio of 38.9%. This
research also observed that particles with larger surface can get more elementary charge.
Moreover, particle penetration decreased with increasing air flow rate and corona voltage of unipolar diffusion charger, and penetration of nanoparticle ( dp<100 nm ) was higher than that of submicron-particle ( 100 nm <dp<1000 nm ). Because, the surface area of nanoparticles is too small, it’s hard for nanoparticles to get enough charge, and be collected. So, there are larger proportion of nanoparticles pass through the flat-plate Electrostatic precipitator, compared with submicron-particles.
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