湿法脱硫工艺对汞的脱除性能研究进展

RESEARCH PROGRESS ON REMOVAL PERFORMANCE OF MERCURY BY WET DESULFURIZATION

汞是煤中一种有毒的重金属痕量元素,汞污染对人类和生物环境造成极大危害,汞具有在大气中的停留时间长,毒性大,在生物体内累积等特性,成为近年来全球研究的热点。本文重点从湿法脱硫工艺上对汞的脱除进行了综述,主要从提高烟气中二价汞比例,同时要抑制脱硫浆液中的二价汞的还原这两方面进行了研究综述,提高WFGD系统脱汞效率的措施有添加氧化剂,气相氧化技术,液相氧化技术,催化氧化技术,光氧化技术,以及电氧化脱汞技术,本文给出它们各自的研究进展及各自的优缺点;抑制零价汞的再释放主要是通过添加沉淀剂的方法实现,在WFGD系统中添加S^(2-)、H^(S-)等还原性离子,使Hg^(2+)形成沉淀从而抑制零价汞的再释放。

Mercury is a toxic heavy metal trace element in coal. Mercury pollution has caused great harm to human and biological environment. Mercury has the characteristics of long residence time in the atmosphere, large toxicity, accumulation in the body and so on. It has become a global hot spotsresearch in recent years .In this paper, the removal of mercury from the wet desulfurization process was reviewed, mainly from the improvement of the Hg2 ＋ in flue gas and the reduction of Hg0 in desulfurization slurry.Measures to improve the mercury removal efficiency of the WFGD system include the addition of oxidants, gas phase oxidation, liquid phase oxidation, catalytic oxidation, photooxidation,electrooxidation and mercury removal.In this paper, the progress and their advantages and disadvantages were given. The re-release of Hg0 is mainly achieved by adding precipitant. The addition of S^2-, H^5- and other reducing ions in the WFGD system to precipitate Hg^2＋ in order to suppressing the re-release of zero-valent mercury.