SCR脱硝过程中细颗粒物排放特性

发布时间：2018-11-02 09:30

【摘要】：为了减少选择性催化还原(SCR)脱硝过程中细颗粒物的形成,针对商用V_2O_5-WO_3/TiO_2脱硝催化剂,采用电称低压冲击器(ELPI)、PM_(10)/PM_(2.5)采样器、X线衍射(XRD)、高分辨率扫描电镜和能谱仪的联用技术(HRSEM/EDX)等对SCR脱硝反应器出口烟气中细颗粒粒径分布、形貌、元素及物相组成等进行测试分析。研究结果表明:SCR脱硝系统出口细颗粒物主要为亚微米级(dp1μm)硫酸铵、硫酸氢铵,同时存在少量硅铝质颗粒;反应温度、NH_3与NO的摩尔比(n(NH_3)/n(NO))、SO_2质量浓度、水蒸气体积分数增加时,细颗粒形成量与SO_2氧化率之间存在显著的关联性,主要因为SO_2氧化成SO_3后,继而与NH_3和H_2O生成硫酸铵、硫酸氢铵细颗粒;O_2体积分数增加促使硅铝质颗粒的形成,但这些硅铝质颗粒物的生成与SO_2氧化量无关,因此O_2体积分数增加时,细颗粒形成量与SO_2氧化率之间相关性略差。降低SO_2的氧化率有助于降低亚微米级硫酸铵、硫酸氢铵细颗粒;控制O_2体积分数有助于减少硅铝质颗粒。
[Abstract]:In order to reduce the formation of fine particles in the process of selective catalytic reduction of (SCR) denitrification, the commercial V_2O_5-WO_3/TiO_2 denitrification catalyst was used in this paper. The low pressure impactor (ELPI),) was used to reduce the formation of fine particles. PM_ (10) / PM_ (2.5) sampler, X-ray diffraction (XRD),) high resolution scanning electron microscope and energy spectrometer (HRSEM/EDX) were used to study the particle size distribution and morphology of fine particles in flue gas from SCR denitrification reactor. Elements and phase composition were tested and analyzed. The results show that the main fine particles at the outlet of SCR denitrification system are sub-micron (dp1 渭 m) ammonium sulfate, ammonium hydrogen sulfate, and a small amount of Si-Al particles. When the reaction temperature, the molar ratio of NH_3 to NO (n (NH_3) / n (NO), SO_2, and the volume fraction of water vapor increase, there is a significant correlation between the formation of fine particles and the oxidation rate of SO_2. The main reason is that after SO_2 is oxidized to SO_3, ammonium sulfate and ammonium bicarbonate are formed with NH_3 and H _ 2O. The increase of volume fraction of O _ 2 promotes the formation of silica-aluminum particles, but the formation of these particles is independent of the amount of SO_2 oxidation. Therefore, when the volume fraction of O _ 2 increases, the correlation between the formation of fine particles and the oxidation rate of SO_2 is slightly poor. Reducing the oxidation rate of SO_2 can help to reduce the submicron ammonium sulfate, ammonium hydrogen sulfate fine particles, and control the volume fraction of O _ 2 to reduce the Si-Al _ 2O _ 2 particles.
【作者单位】：东南大学能源热转换及其过程测控教育部重点实验室;
【基金】：国家重点基础研究发展规划(973计划)项目(2013CB228505) 国家自然科学基金资助项目(51576039)~~
【分类号】：X773

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