Characteristics of fine particulates emission from SCR reactor
Author(s): FAN Hongmei, ZHANG Yuhua, SHU Hang, ZHANG Yaping, YANG Linjun, Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University
Pages: 321-329
Year: 2016 Issue: 1
Journal: Journal of Central South University of Technology
Keyword: SCR; fine particulates; emission characteristics; alumino-silicate particles; NH4HSO4 and(NH4)2SO4;
Abstract: In order to reduce the fine particulates emission from SCR reactor, a study was carried out to characterize the particle size, distribution, morphology, element compositions and chemical compositions of aerosols in the exhaust of a SCR-De NOx system with commercial WO3-V2O5/TiO2 catalysts using electrical low pressure impactor（ELPI）, PM10/PM2.5 samplers, X-ray diffraction, and high resolution scanning electron microscopy/energy dispersive analysis system of X-ray（HRSEM/EDX）. The results show that the majority of fine particles（dp<1 μm） are ammonium sulfate/bisulfate. The small amounts of alumino-silicate particles are detected at the same time. With the increase of temperature, molar ratio of NH3 to NO, and the volume fraction of H2 O and mass concentration of SO2, particle count all significantly contribute to the conversion between SO2 and SO3. The main reason might be the oxidation of SO2 to SO3 with NH3 which generated ammonium sulfate/bisulfate. Alumino-silicate particles yield is promoted by the increase of oxygen volume fraction, although they exerte no impact on SO2-SO3-conversion. So the concentration of particle count poorly correlates with SO2-SO3-conversion. The reduction of SO2 oxidation rate can help decrease the production of ammonium sulfate/bisulfate while less O2 can help decrease the production of alumino-silicate particles.
Pages: 321-329
Year: 2016 Issue: 1
Journal: Journal of Central South University of Technology
Keyword: SCR; fine particulates; emission characteristics; alumino-silicate particles; NH4HSO4 and(NH4)2SO4;
Abstract: In order to reduce the fine particulates emission from SCR reactor, a study was carried out to characterize the particle size, distribution, morphology, element compositions and chemical compositions of aerosols in the exhaust of a SCR-De NOx system with commercial WO3-V2O5/TiO2 catalysts using electrical low pressure impactor（ELPI）, PM10/PM2.5 samplers, X-ray diffraction, and high resolution scanning electron microscopy/energy dispersive analysis system of X-ray（HRSEM/EDX）. The results show that the majority of fine particles（dp<1 μm） are ammonium sulfate/bisulfate. The small amounts of alumino-silicate particles are detected at the same time. With the increase of temperature, molar ratio of NH3 to NO, and the volume fraction of H2 O and mass concentration of SO2, particle count all significantly contribute to the conversion between SO2 and SO3. The main reason might be the oxidation of SO2 to SO3 with NH3 which generated ammonium sulfate/bisulfate. Alumino-silicate particles yield is promoted by the increase of oxygen volume fraction, although they exerte no impact on SO2-SO3-conversion. So the concentration of particle count poorly correlates with SO2-SO3-conversion. The reduction of SO2 oxidation rate can help decrease the production of ammonium sulfate/bisulfate while less O2 can help decrease the production of alumino-silicate particles.
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