Experiments on Mercury Removal by Plasma Enhanced Calcium-Based Sorbent

摘要

Mercury emission from coal combustion has been ranked the fourth biggest pollutants following dusts,rnSO_2andNO_X in China. The non-thermal plasma has been known as functions to oxidize gaseous elementalrnmercury at low temperature effectively. A new method was proposed in this paper of combining plasma withrncalcium-based adsorbent to capture both elemental and oxidized mercury concurrently in flue gas. Experimentalrnstudies on mercury species transformation and adsorption in simulated flue gas by plasma enhanced calciumbasedrnsorbent were carried out in a bench fixed bed reactor. The effects of plasma treating, input energy, plasmarnand calcium oxide interact to removal elemental mercury were investigated in a wire-cylinder non-thermalrnplasma reactor energized by AC power. Voltage and current of non-thermal plasma were measured throughrnoscilloscope, high voltage probe (1000:1) and current probe. Results showed that calcium-based adsorptionrncapacity to mercury was increased remarkably thorough non-plasma strengthened. The removal efficiency ofrnelemental mercury was greatly depended on input energy at which an optimal input energy brought up to 80%rnefficiency. O_3 play an important role in oxidation elemental mercury rather than O under non-thermal plasmarnprocess, Therefore, the main mercury speciation were Hg_2O and HgO_3 rather than HgO.