为达到超低排放标准,某电厂筹备660,WM超临界循环流化床机组时在旋风分离器处安装SNCR脱硝设备.通过实验方法研究温度、氨氮摩尔比(RNS)、氧含量和循环灰对SNCR脱硝的影响.结果表明,温度从800℃提升到950℃,脱硝率不断提高且在950℃达到峰值,再继续升温由于NH3氧化作用脱硝率下降;在温度低于850℃时,温度是反应的控制因素,提升RNS影响不大,在温度超过850℃时,提升RNS会明显提高脱硝率,但RNS大于1.5后,脱硝率增幅放缓;不含氧时,OH等活性基团很少导致SNCR反应进行缓慢,含氧时,氧含量增加会加强NH3氧化减小脱硝率;循环灰含有Fe2O3、CaO金属氧化物可以起到催化作用,加强NH3的氧化反应从而降低脱硝率.%In order to meet ultra-low emission standards,a power plant,when preparing a 660,WM supercritical circulating fluidized bed unit,installs a SNCR denitration device in the cyclone separator.The influence of temperature,ammonia nitrogen molar ratio(RNS),oxygen content and circulating ash on SNCR is studied experimentally.It is found that the temperature rises from 800℃ to 950℃,the denitrification rate increases and reaches the peak value at 950℃,when the temperature continues to rise,the denitrification rate decreases due to NH3 oxidation.When the temperature is lower than 850℃,temperature is the controlling factor of the reaction, andRNS has little influence.When the temperature is more than 850℃,RNS will significantly improve the denitri-fication rate,but whenRNS is greater than 1.5,the rise of denitrification rate will slow down.Without O2,,there are few OH and other active group and SNCR reaction is slow.When oxygen is in the presence,the increase of oxygen content will increase the NH3 oxidation and decrease the denitrification rate.Circulating ash containing Fe2O3 and CaO can play a catalytic role and enhance the oxidation reaction of NH3 to reduce denitrification rate.
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