Removal of Hg0 and simultaneous removal of Hg0/SO2/NO in flue gas using two Fenton-like reagents in a spray reactor

Abstract

A novel process on oxidation removal of elemental mercury (Hg0) from flue gas using two Fenton-like reagents in a spray reactor was proposed. The effects of several process parameters such as H2O2 concentration, Fe3+ concentration, Cu2+ concentration, reaction temperature, solution pH, Hg0 inlet concentration, liquid–gas ratio, NO concentration, SO2 concentration on Hg0 removal were investigated. Reaction mechanism of Hg0 removal was investigated. Simultaneous removal of Hg0, NO and SO2 in flue gas was studied preliminarily. A simple economic estimate for simultaneous removal of Hg0, SO2 and NO was also carried out. Increasing H2O2 concentration, Fe3+ concentration, Cu2+ concentration or liquid–gas ratio significantly promotes Hg0 removal. Increasing solution pH, NO concentration or SO2 concentration significantly inhibits Hg0 removal. Hg0 inlet concentration and reaction temperature have a small impact on Hg0 removal. Oxidation of Hg0 by OH plays a leading role for Hg0 removal. The simultaneous removal efficiencies of Hg0, SO2 and NO are up to 100%, 100%, 85.3% and 100%, 100%, 75.3% using Fe3+ and Cu2+ as catalysts, respectively.