Experimental Study On PH Partition System For High Sulfur And High Alkali Coal Flue Gas Desulfurization

With the rapid development of the national economy,environmental issues have received more and more attention.In recent years,most coal-fired power plants have been equipped with wet desulfurization(WFGD)and selective catalytic reduction(SCR)denitration devices.The sulfur dioxide and nitrogen oxides in coal-fired flue gas have been effectively controlled.However,as domestic high-quality coal is depleted,the proportion of coal-fired power plants burning high-sulfur ash coal will gradually increase.In order to meet more stringent emission standards,the control technology for sulfur dioxide in flue gas after high-sulfur and high-alkali coal combustion needs to be upgraded.The distribution,hazard and combustion characteristics of high-sulfur and high-alkali coal were investigated.The advantages and disadvantages of various desulfurization technologies at the present stage were analyzed and compared.The research idea of deep desulfurization of high-sulfur and high-alkali coal flue gas by pH desulfurization zone system was proposed..The reactor was designed and optimized by Fluent software simulation.The pH zone desulfurization test device was improved and a reactor for desulfurization experiments was produced.The effects of the type of absorbent,partition pH,partition temperature,and flue gas flow on the desulfurization efficiency were tested.The calcium hydroxide was selected for the absorbent.The pH value in the low pH range was 5.5,and the pH value in the high pH range was 7.0.At 60°C,the total flue gas flow rate during the reaction was 5 L/min.Under the optimal experimental conditions,when the concentration of sulfur dioxide is 5000mg/m~3,the outlet concentration of the reactor reaches 17mg/m~3,which meets the requirements of ultra-low emission of coal-fired power plants.The experiment also investigated the effects of nitrogen oxides,carbon dioxide,oxygen and other flue gas components on the desulfurization efficiency and the effects of different concentrations of chloride,bromide and sulfite ions on the desulfurization efficiency of the absorbent slurry.After a series of studies,it is considered that the pH zone desulfurization system is feasible in controlling the concentration of sulfur dioxide emissions in high sulfur coal flue gas.