Research On Speciation And Emissons Of Mercury, Chlorine,fluorine During Coal Utilization

Mercury,fluorin,chlorine emissions from coal utilization have already caused serious damage to environment and human health.Therefore, carring out the research of Hg,F,Cl and find effectively control methods are both important to minimize their emissions.The research is based on mercury,chlorine and fluorine during coal pyrolysis, gasification and combustion. A-bench-scale experiment was designed to investigate the migration and transportation of Hg,Cl,F.Meanwhile, A new sorbent was synthesized and be tested in simulated flue gas on its capacity of mercury removal.The higher the pyrolysis temperature, the more mercury emission.Hg0 remains the dominant form in mercury vapor, with temperature increasing, Hg0 will be partly oxidanted to form Hg2+ and the content of Hg2+ increased in the mercury vapor. Hg0 in pyrolysis was higher than in gasification. Comparing in air to O2/CO2 combustion, it can see that the rate of the mercury emission in air atmosphere was higher than that in O2/CO2 atmosphere but the speciation of mercury is nearly the same . The sorbent ZnFe2O4 in simulated flue gas has good capacity of mercury removal when temperature is high.At this time,the adsorption is more than 85%,and 60 minutes later, the capability of adsorption maintains above 60%.However,when temperature is low or in the nitrogen atmosphere, the sorbent's capacity of mercury removal become weak and can not keep longer.In pyrolysis, temperature is the main factor in release of Cl and F,the higher the temperature, the more release of fluorin and chlorine. Comparing in rapid and slow pyrolysis, it can see that release of Cl and F in slow pyrolysis is higher than that in rapid pyrolysis.