燃煤电站汞排放分布及控制研究的进展

综述了燃煤电站汞排放分布及其控制领域的研究现状。燃煤过程汞各种形态的分布规律可通过多种测量方法获得,理论上可应用平衡热力学以及化学反应动力学来估算烟气、灰渣中汞的分布。平衡热力学的计算结果揭示了各种形态汞形成的基本反应途径,能粗略估计系统在某一平衡态的主要产物分布;而反应动力学应用一系列均相氧化反应和多相反应原理,可描述系统内化合物的生成与反应速度,因而更加接近实际。目前有多种在研的汞控制技术,煤的清洁技术,常规污染物控制技术,如湿法洗涤和烟气中喷入活性炭吸附剂方式等较有发展潜力,但现在还没有一种适用性强的技术可广泛推广,最终汞脱除技术的发展须依赖于理论上的突破。

A Review of Mercury Speciation and Control for Coal-fired Power Plants

A summary of the status of research related to mercury speciation and progress in the development of promising control technologies for coal-fired power plants are provided. Percentage emissions of mercury for coal combustion can be measured based on several methods. Calculations of thermodynamic equilibrium and kinetic mechanisms of chemistry reactions were used to predict the mercury species throughout a combustion system. Equilibrium calculations results were useful in providing a general understanding of mercury reactions and the speciation of mercury. Kinetics mechanisms of homogeneous and heterogeneous mercury chemistry are currently believed to play an important role. Kinetic calculations showed certain mercury compounds form and concentration, however much remains to be learned. Currently many strategies for mercury control are being investigated. The most promising technologies included coal cleaning methods, existing flue gas control technologies such as control in wet scrubbers and dry injection of a sorbent such as activated carbon into the flue gas, There is still no single best technology that can be broadly applied. Significant advances in control technology will depend on understanding the chemical mechanisms of mercury transformation and control.