Dynamic Flocculation of Ultrafine Particles of Coal-Fired Power Plant Induced by Ionic Polyacrylamides at Bench and Pilot Scales

Ultrafine particles or particulate matter emitted from coal-fired power plants pose serious threats to public health. In this work, unique processes for flocculating ultrafine particles were developed and conducted at both bench and pilot scales. The results from dynamic flocculation processes, monitored through a benchtop photometric dispersion analyzer, indicated that ionic polyacrylamide of high molecular weight (MW) induced effective flocculation at concentrations of 1–3 ppm and neutral pH. Such conditions were adopted in a pilot-scale flocculation tower in accordance with the actual operating parameters of a power plant to verify the flocculation of ultrafine particles induced by counter-flow spraying flocculant solution into simulated flue gas. Results showed that the best conditions in pilot trials were to spray the diluted solution of anionic polymer with ultrahigh MW at 20 mL/min, which increased fine particle size from 2.46 to 25.9 μm (floc size), thus demonstrating the effectiveness of the process.