CIESC Journal ›› 2022, Vol. 73 ›› Issue (10): 4410-4418.DOI: 10.11949/0438-1157.20221034

• Catalysis, kinetics and reactors • Previous Articles     Next Articles

Influence of oxygen content in industrial kiln flue gas on NH3-SCR denitration reaction of vanadium-titanium catalysts

Yuxian XIE1(), Tao LIU1, Sheng SU1(), Lijun LIU2, Yuxiu ZHONG1, Zhiwei MA1, Kai XU1, Yi WANG1, Song HU1, Jun XIANG1   

  1. 1.State Key Laboratory of Coal Combustion, Huazhong University of Science & Technology, Wuhan 430074, Hubei, China
    2.School of Mechanical and Electrical Engineering, Wuhan Institute of Technology, Wuhan 430205, Hubei, China
  • Received:2022-07-26 Revised:2022-09-21 Online:2022-11-02 Published:2022-10-05
  • Contact: Sheng SU

工业窑炉烟气氧含量对钒钛系催化剂NH3-SCR脱硝反应的影响

谢玉仙1(), 刘涛1, 苏胜1(), 刘利军2, 钟毓秀1, 马智伟1, 许凯1, 汪一1, 胡松1, 向军1   

  1. 1.华中科技大学煤燃烧国家重点实验室,湖北 武汉 430074
    2.武汉工程大学机电工程学院,湖北 武汉 430205
  • 通讯作者: 苏胜
  • 作者简介:谢玉仙(1997—),女,硕士研究生,z_xieyuxian@163.com
  • 基金资助:
    国家自然科学基金项目(U20A20302)

Abstract:

Currently, industrial kilns mainly use vanadium-titanium-based SCR catalysts to control nitrogen oxides (NO x ) in flue gas. However, the flue gas generated from industrial kilns contains high oxygen content, and the mechanism in the effect of high O2 content on the SCR reaction process over vanadium-titanium catalyst is still unclear. Therefore, the denitration activity of vanadium-titanium catalysts under different O2 contents was experimentally studied. The effects of different O2 contents on the physical and chemical structure of vanadium-titanium catalysts were systematically analyzed by various characterization methods. At the same time, combined with the in-situ infrared technology, the mechanism of SCR denitration reaction of vanadium-titanium catalysts with different O2 contents was further revealed. The results show that high O2 content can improve the low-temperature denitration efficiency of vanadium-titanium catalysts to a certain extent at the reaction temperature of 150—400℃. The increase of the vanadium loading can make the denitration activity temperature window expanding and moving to the low temperature region. After the catalyst undergoes NH3-SCR denitration reaction under different O2 content conditions, its physical structure almost unchanged. Higher O2 content during the reaction can accelerate the SCR denitration reaction by promoting the acid cycle and redox cycle on the catalyst surface. The active intermediates NH3 (L) and NH4+(B) are consumed faster in the SCR reaction process at higher O2 content, and high O2 content can promote the formation of nitrate species and activate the bridge nitrates, thereby enhancing SCR denitration activity of the vanadium-titanium catalyst.

Key words: industrial kiln, high oxygen concentration, NH3-SCR reaction, V2O5/TiO2 catalyst, load

摘要:

目前,工业窑炉主要采用钒钛系SCR催化剂对烟气中氮氧化物(NO x )进行控制,然而工业窑炉部分工序烟气O2含量高,且高O2含量对SCR反应过程的机理影响尚不明确。因此,实验研究了烟气中不同O2含量下钒钛催化剂的脱硝活性,并采用多种表征方法系统分析了O2含量对催化剂物理化学结构的影响;同时结合原位红外技术,进一步揭示了不同O2含量下钒钛催化剂SCR脱硝反应机理。研究表明:在150~400℃的反应温度下,较高O2含量可一定程度提高催化剂的低温脱硝效率,钒负载量增加可使催化剂脱硝活性温度窗口扩展且向低温区移动;催化剂在不同O2含量条件下经过NH3-SCR脱硝反应后,其物理结构变化不明显,反应过程中较高的O2含量可促进催化剂表面酸循环和氧化还原循环,加速SCR脱硝反应;较高O2含量使得SCR反应过程活性中间体 NH3(L)和NH4+(B)消耗加快,促进桥型硝酸盐物种的形成,从而提高其SCR脱硝活性。

关键词: 工业窑炉, 高O2含量, NH3-SCR反应, 钒钛催化剂, 负载量

CLC Number: