Ultrafine Aerosol Penetration through Electrostatic Precipitators

Abstract

This work measures the penetration of ultrafine particles through a single-stage and a two-stage ESP as a function of particle size. Also studied herein are how parameters including particle size, rate of airflow through the ESP, and voltage of the discharging electrode affect aerosol penetration through the ESP. Monodisperse particles with sizes between 10 and 60 nm were generated as the challenge aerosols to investigate the particle charges given by an ESP. A comparison of experimental and theoretical results confirms that a partial charging regime exists when the particle diameter is several tens of nanometers. Experimental results indicated that aerosol penetration through the single- and two-stage ESPs increased significantly for particles below 20 and 50 nm, respectively. However, the exact regime depends on the parameters including airflow rate, applied voltage, and configuration of the ESP. Phenomena such as ionic flow, particle space charge, and flow turbulence may significantly affect the collection efficiency of an ESP for ultrafine particles. To achieve the same collection efficiency, it is more economical to use single-stage ESPs to collect particles less than 16 nm from the standpoint of energy consumption. However, it is more economical to use two-stage ESPs to collect particles larger than 16 nm.

Separation Characteristics of Submicron Particles in an Electrostatic Precipitator with Alternating Electric Field Corona Charger

“…These trends are similar to those reported by Yoo et al (1997) and Zhuang et al (2000). The results suggest that as the particle charge decreased, the penetration increased (Yoo et al 1997;Ylätalo and Hautanen 1998;Huang and Chen 2002;Mainelis et al 2002). As aforementioned, the penetration of either AEF or DEF was reduced as applied voltage and power consumption increased.…”

“…The results suggested that the particle charge increased because the higher attachment of diffusive ions to the greater area of larger particles ). Moreover, the particle charge increased with increasing particle diameter and applied voltage (Huang and Chen 2002;Frank et al 2004;Ji et al 2004;Alguacil and Alonso 2006).…”

Capture of Particles from an Iron and Steel Smelter with a Pulse-Energized Electrostatic Precipitator

“…Their overall mass based capture efficiency typically exceeds 99% (Zukeran et al, 1999a;Huang and Chen, 2002). However, the capture efficiency of the ESPs used in industry in terms of number concentration [number of particles/m 3 (gas)] can be as low as 50-80% (Senior et al, 2000), since most of the submicrometer and ultrafine particles escape from the ESP due to a minimum in the combined effect of diffusion and field charging (Hinds, 1999;Friedlander, 2000).…”

Enhancement of Extrinsic Charging Efficiency of a Nanoparticle Charger with Multiple Discharging Wires

“…Particle charging plays an important role in monitoring and measurement systems, such as an aerosol sizing tool, a differential mobility analyzer (DMA; Knutson and Whitby 1975), and the control of particles by using the electrostatic precipitator (Yoo et al 1997;Huang et al 2002). The former research found that it is difficult to charge ultrafine particles.…”