光氧化反应脱汞技术发展综述

燃煤电厂烟气中汞污染的控制技术研究是目前重要的环保课题之一。气相元素汞成为大气中汞污染的主要来源。文章分析了光氧化反应脱汞技术(包括光化学氧化反应和光催化氧化反应)的反应机理,认为光化学氧化反应技术脱汞均是在紫外光作用下,产生具有强氧化性的基态原子或自由基,将难以脱除的Hg0氧化为高价汞,再通过配套的电除尘器等设备将高价汞捕集,进而达到汞污染控制的目的。不同的是,在光化学氧化反应中,汞的氧化需要借助于电厂烟气中的O2、H2O等成分,而在光催化氧化反应中,反应需要在光催化剂(TiO2或TiO2负载复合物等)的催化作用下进行。阐述了光氧化反应汞脱除技术研究进展。光氧化反应脱汞技术的汞脱除率均可达到60%~70%,具备设备简单、无二次污染等优点。

Review on Mercury Removing Technologies Using Photooxidation Reaction

Mercury control technologies of flue gas would be one of important environmental protection issues in the coal-fired power plant.The reaction mechanism of photooxidation reaction for mercury removal technologies were analyzed,including photochemical oxidation reaction and photocatalytic oxidation reaction.In the photochemical oxidation reaction,the ground state atom or free radicals with strong oxidation were produced and difficult removable Hg0 was oxidized to Hg with higher valence under the irradiation of UV light,and Hg with higher valence could be trapped by the following electrostatic precipitator and removed.In the photochemical oxidation reaction,the oxidation of mercury need the participation of O2 and H2O in the flue gas,while the reactions occur under the catalysis of photocatalysts such as TiO2 or TiO2 supported complex in the photocatalytic oxidation reaction.The research development of photooxidation reaction was elaborated.The mercury removal rate could reach 60%~70% for photooxidation reaction technology,with simple equipment and no secondary pollution.