Removal of Hg~0 and simultaneous removal of Hg~0/SO_2/NO in flue gas using two Fenton-like reagents in a spray reactor

摘要

A novel process on oxidation removal of elemental mercury (Hg~0) from flue gas using two Fenton-like reagents in a spray reactor was proposed. The effects of several process parameters such as H_2O_2 concentration, Fe~(3+) concentration, Cu~(2+) concentration, reaction temperature, solution pH, Hg~0 inlet concentration, liquid-gas ratio, NO concentration, SO_2 concentration on Hg~0 removal were investigated. Reaction mechanism of Hg~0 removal was investigated. Simultaneous removal of Hg~0, NO and SO_2 in flue gas was studied preliminarily. A simple economic estimate for simultaneous removal of Hg~0, SO_2 and NO was also carried out. Increasing H_2O_2 concentration, Fe~(3+) concentration, Cu~(2+) concentration or liquid-gas ratio significantly promotes Hg~0 removal. Increasing solution pH, NO concentration or SO_2 concentration significantly inhibits Hg~0 removal. Hg~0 inlet concentration and reaction temperature have a small impact on Hg~0 removal. Oxidation of Hg~0 by OH plays a leading role for Hg~0 removal. The simultaneous removal efficiencies of Hg~0, SO_2 and NO are up to 100%, 100%, 85.3% and 100%, 100%, 75.3% using Fe~(3+) and Cu~(2+) as catalysts, respectively.