宽温域SCR催化剂上烟气中Hg0的催化氧化机理研究

Collaborative removal of mercury (Hg0) is the most economical technology in coal-fired power plant, by means of the existing selective catalytic reduction (SCR) device. However, the efficiency of demercuration in SCR device is not ideal. Because of the catalyst design and smoke temperature change, as well as other issues, Hg0 catalytic oxidation reaction is not within the best temperature window. Therefore, the preparation of broad temperature windows catalyst is the key to demercuration in existing SCR device, which helps to improvement of Hg0 oxidation within the broad temperature window and without impact on denitration. Others studies have shown that the doping of transition metal catalysts could improve the catalytic activity at the different reaction temperature. Nevertheless, the doping and optimization of SCR catalysts must be based on the Hg0 catalytic oxidation mechanism. Accordingly, the theoretical simulation method based on DFT and experimental methods are applied to discover the mechanism of Hg0 oxidation at the different temperature. The study is aimed at the establishment of rules for modification at the molecular level, and the structure-activity relationship between the catalyst surface properties and Hg0 catalytic oxidation in the macroscopic scale. It provides the theoretical support for the preparation of broad temperature windows SCR catalysts, which with high performance in demercuration. In addition, it has scientific significance for the design and optimization of catalyst at the molecular level.

利用燃煤电厂现有选择性催化还原（SCR）装置协同脱除烟气中单质汞（Hg0），是最经济的脱汞技术。然而，目前SCR装置的脱汞效率不理想，这是因为催化剂设计和烟温变化等问题，导致Hg0的催化氧化反应未能在最佳温度窗内进行。所以，制备宽温域SCR催化剂，使其在较宽温度窗内高效稳定催化氧化Hg0，且不影响脱硝效率，是利用现有SCR装置脱汞的关键所在。研究表明，掺杂过渡金属可在不同温度区间内提高催化剂活性。而SCR催化剂掺杂改性、设计优化的基础和依据是Hg0的催化氧化机理。因此，申请人拟采用基于密度泛函理论的量子化学模拟和实验研究方法，揭示Hg0在改性催化剂上不同温度区间内的催化氧化机理。旨在分子水平上建立宽温域改性剂的筛选准则，在宏观尺度上建立催化剂表面物化性质与Hg0氧化反应之间的构效关系，为制备宽温域、高脱汞性能的SCR催化剂提供理论支持，这对于在分子水平上设计和优化催化剂具有重要的科学意义。

利用燃煤电厂现有选择性催化还原（SCR）装置协同脱除烟气中单质汞（Hg0），是最经济的脱汞技术。然而，目前SCR装置的脱汞效率不理想，这是因为催化剂设计和烟温变化等问题，导致Hg0的催化氧化反应未能在最佳温度窗内进行。制备宽温域SCR催化剂，使其在较宽温度窗内高效稳定催化氧化Hg0，是利用现有SCR装置脱汞的关键所在。本项目利用理论模拟方法结合实验研究方法，揭示了过渡金属元素改性对V/TiO2催化剂表面电子特性的影响机理，探索改性催化剂表面化学性质与Hg0氧化基元反应活化能之间的相关规律，建立理论筛选宽温域改性剂的准则，为制备宽温域、高脱汞性能的SCR催化剂提供理论支持，这对于在分子水平上设计和优化催化剂具有重要的科学意义。