| So far, a series of mature technologies have successively developed to remove single pollutant such as dust, SO2, NOx, and some have been the mainstream processes in the market and applied in engineering, such as electrostatic precipitation technology, wet flue gas dcsulfurization technology with calcium base absorbent, selective catalytic reduction (SCR) denitration technology, selective non-catalytic reduction (SNCR) denitration technology and mercury technology with activated carbon. But it has obvious characteristic that one technology is only used to remove one pollutant by a set of special equipment. For multi-pollutant removal, the graded treatment mode has some problems such as big floor occupation, high equipment investment and operating cost, high energy consumption, less stability of flue gas system. In order to obtain better economy and applicability of the coal-fired pollution control, the research on simultaneous removal of multi-pollutants has important realistic significance, and has become a current new field in both at home and abroad.Based on the current research focus, the influence factors on removal efficiencies of SO2 and NO in two new complex absorbent system including the solution of NaClO2/NaCIO and alkaline solution of H2O2 were investigated detailedly in this paper.These factors such as solution pH, absorbent concentration, reaction temperature, absorbent composition and proportion have significant effects on removal efficiencies of SO2 and NO. The best experimental conditions of desulfurization and denitration were obtained based on two new complex absorbent system. The optimal removal conditions based on the solution of NaClO2/NaClO included the solution pH was 5.5, the molar ratio of NaCIO to NaCIO2 was 4, and the absorption temperature was 50℃. Under the best conditions, the removal efficiency of SO2 reached almost 100%, and the removal efficiency of NOx reached 80%. The optimal removal conditions based on the alkaline solution of H2O2 included the solution pH was 10.5, the H2O2 concentration was 0.8175 mol·L-1, and the absorption temperature was 47.5℃. Under the best conditions, the removal efficiency of SO2 reached almost 100%, and the removal efficiency of NOx reached 70%.The removal reaction mechanisms was revealed according to product analysis results of desulfurization and denitration, the oxidation absorption reactions of SO2 and NO with chlorite anion, hypochlorite and intermediate products such as chlorine dioxide and chlorine could occur when solution of NaClO2/NaClO was used as complex absorbent. Moreover, the oxidation reactions may happen in both gas phase and liquid phase. The oxidation absorption reactions of SO2 and NO with hydrogen peroxide, peroxide anion and related free radicals could occur when alkaline solution of H2O2 was used as complex absorbent.The macro-kinetics experimental results of simultaneous desulfurization and denitration indicated that the apparent reaction orders of SO2 and NO were both one order, and the apparent activation energies were 21.598 kJ·mol-1 and 8.166 kJ·mol-1 respectively when the solution of NaClO2/NaC10 was used as complex absorbent; the apparent reaction orders of SO2 and NO were both one order, the apparent activation energies were 1.3784 kJ·mol-1 and 3.7220 kJ·mol-1 respectively when the alkaline solution of H2O2 was used as complex absorbent. For simultaneous desulfurization and denitration using alkaline solution of H2O2, the inhibition of SO2 existed in the absorption of NO and the facilitation of NO existed in the absorption of SO2; the effect of SO2 on NO absorption rate was liner with 1.2 power exponent of its partial pressure in gas phase, and the apparent activation energy was 46.634 kJ·mol-1; the effect of NO on SO2 absorption rate was liner with 2.8 power exponent of its partial pressure in gas phase, and the apparent activation energy was 155.86 kJ·mol-1. The experimental results of mass transfer and reaction kinetics indicated that the mass transfer was the control step in the absorption of SO2 and reaction process was the control step in the absorption of NO; the obtained apparent activation energies for pseudo-first-order reaction were 42.654 kJ·mol-1 and 27.768 kJ·mol-1 respectively.
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