基于在线质谱定量分析的生物质焦炭还原NO反应动力学

Kinetics of NO reduction by biomass char based on the quantitative analysis via on-line mass spectrometer

针对生物质焦炭还原NO反应提出基于等效特征图谱法的在线质谱定量分析方法,对固定床等温条件下生物质焦炭还原NO过程进行分析,确定了还原反应过程中每种气体产物的实时质量流量。结果表明:气体产物中CO、CO_(2)和N_(2)同时存在时,使用定量分析方法可将以上3种气体重叠的电流值进行拆分,进而得到每种气体产物的质量流量值。通过与标气对比,验证了定量方法的准确性。针对生物质焦炭还原NO反应,利用基于等效特征图谱法的在线质谱定量分析方法探究了温度对生物质焦炭还原NO反应的影响,并利用模型拟合法对还原反应动力学参数进行求解。结果表明,CO和N_(2)为还原反应的主要产物,参与还原反应的NO中98%的N转化为N_(2)。通过在线质谱定量分析方法计算反应动力学参数表明:800~950℃时机理函数G(x)=1-(1-x)^(1/2)可描述生物质焦炭还原NO反应中焦炭的转化过程,还原反应的活化能为113.46 kJ/mol。

A quantitative analysis method via on-line mass spectrometry based on the equivalent characteristic spectrum analysis method was developed to analyze the NO reduction process of biomass char under fixed-bed isothermal conditions,and mass flow rate of each gas during the reduction process were determined.The results show that the quantitative method could accurately calculate the flow rate of each gas even though there are ion currents overlapping at mass-to-charge ratio when CO,CO_(2)and N_(2)are simultaneously present in an on-line mass spectrometer.The accuracy of the quantitative method was determined by comparing the calculated mass flow rate values with the actual mass flow rate values.The effect of temperature on the NO reduction reaction of biomass char was investigated.The kinetic parameters of the reduction reaction were solved using the model fitting method.In the reduction of NO by biomass char,CO and N_(2)are the main products,and more than 98%of N in NO is converted to N_(2).The mechanism function G(x)=1-(1-x)^(1/2)could describe the char conversion process in the NO reduction reaction when the temperature interval is 800-950℃.The activation energy of the reduction reaction was calculated to be 113.46 kJ/mol.