Experimental Investigation On Selective Reduction Of NO By NH₃ From Fuel Gas In Coal-Fired Boiler

NO_x is one of the main air pollutants.It has been a hot research in the international environmental field to control and treat NO_x pollution.Flue gas denitrification technology is one of effective abating NO_x methods from stationary sources such as power plants and industrial boilers,which mainly includes selective catalytic reduction（SCR）technology and selective non-catalytic reduction（SNCR）technology.This work was involved in the flue gas denitrification technology using NH₃ as reductant,including selective catalytic reduction of NO with NH₃ over high-iron fly ash catalyst and selective non-catalytic reduction of NO with NH₃.This thesis studied two typical high-iron fly ashes of 1# power plant and 2# power plant in Guizhou Province and made the multi-perspective analysis on them.Nitrogen adsorption method was used to measure BET specific surface area and specific pore volume;the phase structure of fly ashes was analied by XRD;the surface micro-profiles was observed by SEM.It can be conclude that the fly ashes contain Fe₂O₃ as SCR catalytic activities and Fe₂O₃ exists in particles with specific micro-profiles.This thesis made the experimental investigation of selective catalytic reduction of NO with NH₃ over high-iron fly ash catalyst in the temperature range of 200℃-550℃.The efficient temperature range of SCR over different high-iron fly ash catalyst and the influence of NH₃/NO_x mole ratio were found, which has important guiding significance to the application of high-iron fly ash catalyst.The experimental investigation of selective non-catalytic reduction of NO with NH₃ was achieved in constant temperature area.The work found the efficient temperature range of SNCR and the influence of reaction temperature,reaction time,NH₃/NO_x mole ratio,mixed degree of NH₃ and fuel gas,water vapor content in fuel gas to SNCR.