AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Charge Characterization of Nanoparticles Exiting Non-thermal Atmospheric Pressure Plasmas
GIRISH SHARMA, Nabiel Abuyazid, Sukrant Dhawan, R. Mohan Sankaran, Pratim Biswas, Washington University in St Louis
Abstract Number: 881 Working Group: Control and Mitigation Technology
Abstract Electrostatic precipitators (ESPs) have been widely employed in coal power plants for particle removal. Traditional ESPs use a corona discharge for particle charging, which are then captured with the DC electric field. Corona is a form of gas discharge with typical values of ion concentration on the order of 1014-1016 #/m3, which is on the lower end of among atmospheric discharges. Radio-frequency (RF) and kHz driven dielectric barrier discharges (DBD) are observed to be several orders of magnitude larger in ion concentration. Our understanding is that particle charging improves with larger ion concentrations. Thus, we explore the possibility of using RF/kHz plasma for particle capture technologies.
In this poster, we present the charge characterization of atmospheric pressure non-thermal RF plasma and DBDs. First, ion concentration is calculated in the pristine plasma for both plasma power sources, obtained from the resistivity of the discharge. Following this, particle-plasma interaction is studied in two different flow configurations. the first configuration conducts particles through the plasma. In the second configuration, the aerosol flow passes perpendicularly through the plasma region past the ground electrode, so called plasma jet. The plasma jet region is characterized by the relaxation of energetic species, visible from the decay of optical emission. In this region, charged species are still present but to a lesser extent. Despite the decrease in charged species concentration, it still presents promise as the cross-flow configuration introduces flexibility and variety to the charging system.
The particle size distribution, and particle charge distribution is measured downstream of the charged region. Moreover, the fraction of multiple charged particles is measured for the particle size distribution using a tandem DMA system. The performance of AC-driven plasmas is evaluated against the traditional DC corona by comparison of particle charge fractions.