Effects Of Fly Ash On Mercury Speciation Conversion In The Flue Gas And Mercury Measurement Technologies Research

Founded by the International Key Cooperative Project between Institute for Thermal Power Engineering of Zhejiang University, U.S. DOE and U.S. EPA -"Coal-fired Mercury Emission and control of China", a detailed research of Effects of fly ash on Mercury Conversion in the Flue Gas and Mercury Measurement Technology was carried out, which will accelerate the development of Coal-fired mercury control technology and help to improve the mercury measurement technologies in coal-fired fuel gas. Besides as one part of the Project, Ontario-Hydro method was applied to determine the mercury speciation in fuel gas of 300MW Coal-fired Boiler, which will supply reliable data for the estimation of Coal-fired mercury emission of China.Based on the previous researches, the method using sized fly ash was established. A bench-scale testing apparatus was constructed to evaluate the effect of whole fly ashes and sized fly ashes on mercury conversion in the simulated flue gas. Moreover applying the software Minitab analyzed the data derived from the testing.Firstly, fly ashes were sized which were derived from #1 and #2 boilers of Beilun Power Plant in Zhejiang University, and got sized fly ash samples including different particle sizes, magnetic phases and nonmagnetic phases. Besides some analysis apparatuses were used to describe the characterization of these fly ash samples including Morphology, chemical composition, surface area, unburned carbon etc.Secondly, a bench-scale testing apparatus was constructed to evaluate the effect of whole fly ashes on mercury conversion in the simulated flue gas. The result showed that fuel gas component and fly ash type were the two most important factors to mercury conversion. Of the gases added to the baseline blend, the gas species having the greatest effect on Hg oxidation was NO2. Next in significance with respect Hg oxidation was NO. The presence of SO2 actually appears to inhibit oxidation in the presence of other gases, which attributed to the reducibility of SO₂. The oxidation ability of HCl was less significant than NO and NO₂, which was ascribed to the true reason of effecting Hg oxidation was Cl -...