Abstract Mercury (Hg) emission from coal combustion has attracted considerable public concern because of its harmful effects on human health and the ecosystem. The fundamental understanding of the reaction mechanisms and chemical kinetics that govern the transformation of Hg0 to Hg2+ and Hgp in coal-fired flue gas is crucial for mercury emission control. Kinetic calculations with quantitative predictability are critical to scaling up laboratory experiments to pilot- or full-scale tests. Despite extensive research over the last two decades, there remain many unresolved issues that can limit our ability to make useful engineering predictions and hence the potential for mercury emission control. This review discusses recent progress in the study of reaction mechanisms and kinetics of mercury oxidation over a wide temperature range, with a specific focus on the heterogeneous reaction mechanism of mercury adsorption, conversion and desorption on solid surfaces. Thermochemical properties of relevant mercury species are the basis of thermodynamic predictions. They are reviewed and provided first. Various methods and theories for evaluating and estimating kinetic rate parameters of elementary reactions are surveyed from existing experiments and theoretical studies. Further, the chemical reaction kinetics of mercury oxidation is discussed with an emphasis on two primary aspects of the problem: (i) the development of homogeneous reaction mechanisms using quantum chemistry calculations and (ii) the advancement of heterogeneous reaction mechanisms in which kinetic parameters of surface reactions are fitted to experimental data. Various kinetic models are tested against selected experimental data, the corresponding performance of each kinetic model is compared and evaluated. Finally, we provide an outlook on the reaction mechanisms and kinetics of mercury transformation during coal combustion.

中文翻译：

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煤燃烧过程中汞转化的反应机理和化学动力学

摘要 煤炭燃烧产生的汞（Hg）排放对人类健康和生态系统产生有害影响，引起了公众的广泛关注。对控制燃煤烟气中 Hg0 向 Hg2+ 和 Hgp 转化的反应机制和化学动力学的基本了解对于汞排放控制至关重要。具有定量可预测性的动力学计算对于将实验室实验扩大到中试或全面测试至关重要。尽管在过去的二十年中进行了广泛的研究，但仍有许多未解决的问题会限制我们做出有用的工程预测的能力，从而限制汞排放控制的潜力。本综述讨论了汞氧化在较宽温度范围内的反应机制和动力学研究的最新进展，特别关注汞在固体表面吸附、转化和解吸的多相反应机理。相关汞种类的热化学特性是热力学预测的基础。它们首先被审查和提供。从现有的实验和理论研究中调查了用于评估和估计基本反应动力学速率参数的各种方法和理论。此外，还讨论了汞氧化的化学反应动力学，重点是该问题的两个主要方面：(i) 使用量子化学计算开发的均相反应机制和 (ii) 非均相反应机制的进步，其中动力学参数表面反应符合实验数据。针对选定的实验数据测试各种动力学模型，比较和评估每种动力学模型的相应性能。最后，我们对煤燃烧过程中汞转化的反应机制和动力学进行了展望。