焦炉蓄热耦合SNCR+SCR脱硝特性数值研究  

Numerical Study on the Denitration Characteristics of Coke Oven Regenerative Coupled SNCR+SCR

作　　者：赵玉杰 冯俊小 李卫东 陈艳梅 ZHAO Yujie;FENG Junxiao;LI Weidong;CHEN Yanmei(School of Energy and Environmental Engineering,University of Science and Technology Beijing,Haidian District,Beijing 100083,China;Anshan Iron and Steel Research Institute,Anshan 114003,Liaoning Province,China;School of Chemistry,Chemical Engineering and Environment,Minnan Normal University,Zhangzhou 363000,Fujian Province,China)

机构地区：[1]北京科技大学能源与环境工程学院,北京市海淀区100083 [2]鞍钢钢铁研究院,辽宁省鞍山市114003 [3]闽南师范大学化学化工与环境学院,福建省漳州市363000

出　　处：《中国电机工程学报》2022年第4期1504-1513,共10页Proceedings of the CSEE

基　　金：国家重点研发计划项目(2017YFC0210303)。

摘　　要：针对当前焦炉烟气脱硝应用选择性非催化还原(selective non-catalytic reduction,SNCR)或选择性催化还原(selective catalytic reduction,SCR)存在的问题,建立具有喷氨空间的新型蓄热室内耦合SNCR+SCR的三维模型。通过数值模拟方法,优化和评价不同蓄热材料物性参数的蓄热指标,分析SNCR及SCR反应区的温度及NO/NH_(3)浓度分布特性。结果表明:耦合脱硝过程从SNCR到SCR依次发生,并具有明显的温度梯度变化及余热梯级利用特性。SNCR反应区的粒子停留时间较大,保证了NH_(3)与NO的混合程度,实现63.8%的NO还原效率。此外,SNCR过程同时存在NO还原与NH_(3)氧化的竞争反应,主体反应区位于注射面以上。由于SCR反应区的NH_(3)浓度低及分布不均匀而具有较低的还原效率,这也与蓄热室结构特性及催化剂涂覆面积有关,而在单独SCR工艺中获得大约36%的NO还原效率。研究结论说明,SNCR主要承担NO减排及SCR进一步降低NH_(3)浓度的耦合脱硝过程,能够实现NO/NH_(3)出口浓度的双重达标,为替代外延SCR脱硝系统提供理论依据。Aiming at the current problems of coke oven flue gas application selective non-catalytic reduction(SNCR) or selective catalytic reduction(SCR) process denitration, a three-dimensional model of coupled SNCR+SCR in a new regenerator with ammonia injection space was established.Through the numerical simulation method, the heat storage index of different material physical parameters was optimized and evaluated, and the temperature and NO/NH_(3)concentration distribution characteristics of SNCR and SCR reaction zone were analyzed. The results showed that the coupled process occurred sequentially from SNCR to SCR, and it had obvious temperature gradient variation and cascade utilization characteristics of waste heat. The residence time in the SNCR reaction zone was relatively large, ensuring the mixing degree of NH_(3)and NO, and achieving a NO reduction efficiency of 63.8%. In addition, the SNCR process also had a competitive reaction of NO reduction and NH_(3)oxidation, and the main reaction zone was located above the injection surface. Due to the low concentration and uneven distribution of NH_(3), the SCR reaction zone had a low reduction efficiency, which was related to the structure of the regenerator and the catalyst coating area.However, the NO reduction efficiency of about 36% was obtained in a single SCR process. It indicated that the coupled process that NO reduction in the SNCR process and further reducing the NH_(3)in the SCR process could achieve the outlet NO/NH_(3)concentration to meet the emission standard,providing a theoretical basis for replacing the epitaxial SCR denitrification system.

关 键 词：焦炉蓄热室 选择性催化还原 选择性非催化还原 NO减排 耦合脱硝 数值模拟 

分 类 号：X511[环境科学与工程—环境工程]