Feasibility of improving dust removal efficiency of fly ash fine particles for coal-fired power plants

Abstract

As solid waste of coal-fired power plants, atmospheric environmental pollution is caused by fly ash during transportation. The purpose of this study was to improve the dust removal efficiency of fly ash fine particles by electrocoagulation and obtain reasonable operating parameters. The effects of particle concentration, gas velocity, AC frequency, and voltage on particle electrocoagulation efficiency were studied through the establishment of a discrete element soft sphere calculation model, and reasonable electrocoagulation operation parameters were obtained. The dust removal process was evaluated according to the particle number concentration, electrocoagulation efficiency, and particles microscopic characteristics due to the dust removal experiments of fly ash by electrocoagulation. The results demonstrated that increasing particle concentration, reducing gas velocity, and selecting reasonable AC frequency and voltage were effective to improve the real-time electrocoagulation efficiency and its stability. Under the suitable conditions: voltage of 3 kV, airflow velocity of 5 m s^–1, particle concentration of 30 mg m^–3 and AC frequency of 100 Hz, the electrocoagulation efficiency was higher than 40%. The electrocoagulation was effective to improve the dust removal efficiency of fly ash fine particles with a relative humidity of air below 70% and ambient temperatures above 20°C.