燃煤电厂是最主要的人为汞排放污染源,氯元素对汞的形态转化及脱除率有非常重要的影响。本文概述了燃煤电厂汞的释放特性和现有控制技术,从氯元素作为烟气组分、活性炭改性物以及燃料添加剂这3个方面详细阐述了氯对汞排放控制的影响。首先氯化氢作为烟气组分,对单质汞向氧化态汞的形态转化有促进作用,这有利于现有除尘、脱硫装置对烟气汞的脱除。含氯化合物改性活性炭吸附剂时,物理吸附和化学吸附同时存在,这能有效提高吸附剂对汞的吸附性能。氯化物作为燃煤添加剂也能有效促进烟气汞的氧化和脱除,其中氯元素在湿法脱硫废水中富集,如何把其利用到烟气汞的脱除对开发高效脱汞技术有重要的意义。同时,比较了以上3种氯添加方案的优缺点。最后指出,深入研究氯元素对汞作用机理是今后的研究方向。%Coal-fired power plant is the largest source of anthropogenic mercury emissions.There is a close relationship between chlorine and the transformation of mercury species and mercury removal rate.The characteristics of mercury releasing from coal and emerging mercury removal technologies are summarized.The effects of chlorine on mercury control are illustrated from three aspects：elemental chloride as flue gas component,elemental chloride in adsorbents＇ chemical treatments and elemental chloride as additives in coal combustion.Firstly hydrogen chloride as flue gas component,has a positive role in promoting elemental mercury conversion to oxidized mercury which is easier to be removed by existing dust separation plant and desulfurization devices.It is shown that chloride-modified activated carbon adsorbent has better adsorption performance,because physical adsorption and chemical adsorption exist at the same time.Chloride as coal-burning additives can also be effective in promoting mercury oxidation and mercury removal from flue gas.Elemental chlorine from coal then is enriched in the wet FGD wastewater,so how to use it to develop new effective mercury removal technology is very important.The advantages and disadvantages of the above three methods of chlorine addition are compared.Finally future research direction of the mechanism of chlorine in mercury removal is proposed.
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