CO和H_(2)协同非催化还原NO反应特性研究  

Reaction Characteristics of Synergistic Non⁃Catalytic Reduction of NO by CO and H_(2)

作　　者：谢亚宁 曹国强[2] 贾广信 胡东海[2,3] 王永斌 聂伟 李春玉[2] 赵建涛[2] XIE Yaning;CAO Guoqiang;JIA Guangxin;HU Donghai;WANG Yongbin;NIE Wei;LI Chunyu;ZHAO Jiantao(School of Chemistry and Chemical Engineering,North University of China,Taiyuan 030051,China;State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中北大学化学与化工学院,山西太原030051 [2]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001 [3]中国科学院大学,北京100049

出　　处：《中北大学学报（自然科学版）》2024年第3期383-390,共8页Journal of North University of China(Natural Science Edition)

基　　金：中国科学院战略先导专项(XDA29050100)。

摘　　要：研究氮氧化物(NOx)的非催化还原反应行为对控制其排放具有重大意义。在反应温度为800~1400℃、气氛条件为VCO∶VH_(2)=3∶1~1∶3的体积比、还原气体的体积比为VNO∶VCO+H_(2)=1∶1~1∶6、停留时间为2.7~7.2 s条件下,在高温固定床反应器中考察了氮氧化物非催化还原反应行为,并使用Chemkin软件进行了动力学模拟。研究表明,在800~1400℃温度范围内,NO还原率随着温度的升高而提高,尤其在1300~1400℃提升率更为明显;增加还原气体的用量,有利于提高NO还原率;延长还原气的停留时间,亦可提升NO的还原率;通过对照CO和H_(2)各自还原NO反应可知,H_(2)较CO的还原能力更强。在混合气体中增加H_(2)浓度有助于提高NO还原率。通过对动力学计算中单独CO、H_(2)气氛以及CO和H_(2)混合气氛还原效果的比较,发现CO和H_(2)具有协同还原NO的效果,混合气氛可提升NO的还原率约6%。通过对NO还原过程的基元反应进行动力学分析确定了CO和H_(2)的还原NO的反应路径。结果证明H_(2)的还原能力比CO更强的原因在于其参与所有基元反应的速率均高。经过进一步路径分析可知,CO和H_(2)协同还原NO的关键反应步骤在于HONO中间产物的生成。It is of great significance to investigate the non-catalytic reduction of nitrogen oxides(NO_(x))regarding its emission control.The non-catalytic reduction behavior of nitrogen oxides was investigated in a high-temperature fixed-bed reactor under the conditions of reaction temperature(800–1400℃),gas con-ditions (VCO∶VH_(2)=3∶1–1∶3),the volume ration reducing gas concentration(VNO∶VCO+H_(2)=1∶1–1∶6),and residence time(2.7–7.2 s),and kinetic simulations were carried out by using Chemkin software.It is shown that the reduction rate of NO increases with increasing temperature in the temperature range from 800 to 1400℃,especially from 1300 to 1400℃.Increasing the usage of reducing gas is favorable to increase the reduction rate of NO,and prolonging the residence time of the reducing gas can also enhance the reduction rate of NO;by comparing the NO reduction reactions of CO and H_(2) respectively,it can be seen that the reduction ability of H_(2) is stronger than that of CO.Increasing the concentration of H_(2) in the gas mixture helps to increase the NO reduction rate.Comparison of the reduction effects of CO and H_(2) respective gas and the mixed gas of CO and H_(2) by kinetic calculations reveals that there is a synergistic effect on NO reduction between CO and H_(2),and the mixed gas can enhance the NO reduction rate by about 6%.The reaction pathways for NO reduction by CO and H_(2) are determined by kinetic analysis of the elementary reactions of the NO reduction process.It is demonstrated that the reason for the greater reduction capacity of H_(2) than CO is due to the high rates of all the elementary reactions in which it is involved.After further pathway analysis,the key reaction step in the synergistic reduction of NO by CO and H_(2) lies in the generation of HONO as intermediate product.

关 键 词：氮氧化物 固定床反应器 非催化还原 协同效应 

分 类 号：X511[环境科学与工程—环境工程]