Development of a wet electrostatic precipitator for subway platform particles collection

Recently, many researchers have paid a lot of attention to growing concentrations of ultrafine particles in the atmosphere. In particular, it has been reported that the air quality in indoor public places such as subway platforms, underground markets and indoor parking lots are even 3-5 times worse than the in-flowing air from outside due to the stationary air surroundings. Here, we designed and developed the electrospray-driven wet electrostatic precipitator to effectively collect Sub-1 um particles on a subway platform. The electrospray is one of the most attractive spray techniques to produce very fine and highly charged water droplets from high intensity electrical potential between two oppositely charged electrodes. The particles (PM10, PM2.5 and PM1.0) collection performance was investigated experimentally for different water supply and applied voltages at the conditions of inlet dust load of 160-200 mg/m3, air flowrate of 5.5 m3/min and inlet air velocity of 1.0 m/s. Through measuring the particle concentrations at both inlet and outlet ports by the optical particle sizer (OPS), we calculated the maximum collection efficiency as 99.8%, 98% and 86.7% for PM10, PM2.5 and PM1.0, respectively.