The Research On The Removal Efficiency Of Mercury From Coal-fired Flue Gas By γ-Al₂O₃Loaded CeO₂and CuO

As a highly toxicity, volatility, bioaccumulation in the life and food chain, mercury exerts a large adverse effect on human heath. Coal-fired power plants are considered to be the primary anthropogenic source of mercury emission to the atmosphere. Mercury pollution emissions from coal-fired utility boilers has been recognized as another major pollution problems after sulfur dioxide pollution, coal combustion control of mercury pollution is one of the most important environmental issues, how to control the flue gas mercury emissions, development efficient, low-cost, no secondary pollution for flue gas mercury removal technology has become a research focus, is also an important task which governments faced. At present, domestic and foreign about forms conversion and control method of mercury is still in the exploratory stage, the side of development effective adsorbent and mercury removal mechanism is still very weak. Therefore, the active mercury pollution research for development of a cost-effective mercury removal technology is imminent.This paper reviews the sources of mercury pollution in the environment, mercury on the environment and human health hazards of mercury emissions from coal-fired power plant morphology, and transformation of mercury form, the factors that affect the distribution of mercury species as well as on current international emission control technologies and mercury measurement introduced catalyst selection, preparation and characterization methods. To an equal volume of the final selection of prepared CeO2/γ-Al2O3soaked and CuO/γ-Al2O3as the catalyst used in the study, and of the catalysts were characterized using BET and XRD.Experimental part first used Ce(NO3)3·6H2O and CuSO4·5H2O as precursor CeO2and CuO according to isovolumetric impregnation in the preparation of γ-Al2O3loading different values of cerium oxide and copper oxide. To study the efficiency of CeO2/γ-Al2O3and CuO/γ-Al2O3at different loading values of and different conditions, some experiments were carried in a small simulation experiment. Experimentally derived ceria loading of9%and copper oxide loading of15%of the mercury removal efficiency are the best; the mercury removal efficiency of CeO2/γ-Al2O3increased with the loading increases firstly and then decreases,9%CeO2/γ-Al2O3at350℃has the highest mercury removal efficiency (reaching to86.76%); mercury removal efficiency increased with the reaction temperature was first increased and then decreased, at350℃, the removal efficiency reach to highest. The mercury removal efficiency of CuO/γ-Al2O3increase with the load value increased, when the CuO loading of15%, the mercury removal efficiency of up to83.6%. And the mercury removal efficiency of CuO/γ-Al2O3increased with the reaction temperature increased, results showed that430℃is the optimum temperature. In constant conditions, with the reaction time, the removal efficiency of virgin γ-Al2O3becoming lower and lower, while the load has CeO2and CuO of γ-Al2O3in the removal efficiency of mercury is stable in a short time, but with the prolong of reaction time, the mercury removal efficiency will be slowly decreased.The study also examined the NO, SO2, O2and H2O (g) of mercury removal efficiency, experiments result show that CeO2/γ-Al2O3and CuO/γ-Al2O3have different mercury removal efficiency in different atmospheres. Experimental gas composition and concentration has positive/negative effect on mercury removal efficiency. The removal of mercury SO2CeO2/γ-Al2O3plays a positive effect on the removal of mercury of CeO2/γ-Al2O3and the opposite role to CuO/γ-Al2O3. In addition to outside SO2, NO, O2and H2O (g) of mercury removal in the two plays the same role in the process (NO and O2removal of mercury in both play active role in the process, H2O (g) plays an inhibitory role).