Removal of elemental mercury from flue gas by recyclable CuCl2 modified magnetospheres from fly ash. Part 4. Performance of sorbent injection in an entrained flow reactor system

Abstract

Experimental studies on Hg0 removal by CuCl2 modified magnetospheres (Cu6–MF) injection were performed in an entrained flow reactor system. The factors affecting the Hg0 removal efficiency were investigated, including the initial Hg0 concentration, sorbent concentration in flue gas, sorbent particle size, sorbent residence time in flue gas, and flue gas temperature. The results indicated that, as the raise of initial Hg0 concentration, the Hg0 removal efficiency increased. The Hg0 removal efficiency also increased with the increase of sorbent residence time and sorbent concentration in flue gas. When the residence time was 1.61 s and the sorbent concentration was 1.09 g/m3, the Hg0 removal efficiency could reach to 80.6%. However, with the further increase of residence time and sorbent concentration, the Hg0 removal efficiency did not increase continuously. The smaller particle size was favorable for the Hg0 removal. In the industrial application, the particle size could be selected as 45–74 μm when comprehensively considering the Hg0 removal efficiency, the cost of sorbent preparation, and other factors. The acid flue gases have negligible impacts on Hg0 removal, while moisture plays a slightly negative role in Hg0 removal under SFG atmosphere. With the superior Hg0 removal performance, the Cu6–MF sorbent may presents great potentials for Hg0 removal in coal-fired power plants.