Poisoning mechanism and regeneration process of the denitration catalyst

doi:10.16085/j.issn.1000-6613.2015.12.001

Abstract

Abstract: As selective catalytic reduction is widely used for eliminating NO_x in thermal power plant,researches on poisoning mechanism and regeneration process of the denitration catalyst have drawn more and more attention. This paper makes a systematic review on the physical and chemical poisoning mechanism and regeneration process of the denitration catalyst. The poisoning mechanism can be summarized into three categories:the deposition of particles or created salts on the surface of the catalyst which blocks the pores on the catalyst; the reaction between poisons and the active site which reduces the acidity and redox performance of the surface; structural damage and irreversible phase transition of the catalyst. As for the regeneration of the catalyst,this paper gives a detailed description of the regeneration process,compares advantages and disadvantages among different regeneration technologies and introduces a demonstration project of the high-calcium catalyst regeneration. In the project,the relative activity of the regenerated catalyst,compared to fresh catalyst,was recovered to 0.96. Moreover,only 1.0% SO₂ was oxidized and each quality index of the regenerated catalyst reaches the level of the fresh catalyst. This paper is important for extending catalyst's lifespan and developing its regeneration technologies through in-depth discussion about poisoning mechanism and regeneration process.

Key words: denitration, selective catalytic reduction (SCR), catalyst, poisoning, regeneration

摘要： 随着烟气脱硝系统在火电厂的应用,对选择性催化还原催化剂的中毒机理和再生工艺的研究受到广泛关注。本文系统综述了脱硝催化剂的物理及化学中毒机制、再生方法及工艺。在中毒机制方面,将不同中毒机制归为三类:颗粒物或生成盐沉积在催化剂表面,堵塞催化剂通道和孔道;毒物与活性中心作用使表面的酸性性能和氧化还原性能降低;催化剂结构破坏和发生不可逆相变。在催化剂的再生方面,本文详细介绍了失活催化剂的再生工艺流程和再生液的选择,比较了不同再生技术的针对性和优缺点,最后介绍了电厂高钙项目的再生工业示范,其再生催化剂的相对活性恢复到原来的0.96,SO₂氧化率为1.0%,且各项指标达到了新鲜催化剂的水平。本文对延长催化剂使用寿命和制定废弃催化剂再生工艺具有重要指导意义。

关键词: 烟气脱硝, 选择性催化还原, 催化剂, 中毒, 再生

CLC Number:

TQ032
X511

LI Xiang, LI Junhua, HE Xu, PENG Yue, CHANG Huazhen, HUANG Rui, LIU Wei, HAO Jiming. Poisoning mechanism and regeneration process of the denitration catalyst[J]. Chemical Industry and Engineering Progree, 2015, 34(12): 4129-4138.

李想, 李俊华, 何煦, 彭悦, 常化振, 黄锐, 刘伟, 郝吉明. 烟气脱硝催化剂中毒机制与再生技术[J]. 化工进展, 2015, 34(12): 4129-4138.

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