低共熔溶剂选择性脱除烟气中一氧化氮的机理研究

NOx exhausted from coal-fired power plant is not only the main atmospheric pollutant, but the major reason for the formation of hazy weather in China. Current denitrification methods (e.g., SCR, NSCR and etc.) have many shortcomings, such as huge disposable investment and high operating cost, which limit their commercial applications. As such, new high-performance flue gas denitrification technologies are urgently required to reduce NOx emission and control haze. NO counts approximate 95% of the total amount of NOx in the flue gas; however, currently it is still the issue that NO cannot be selectively removed with high efficiency and low cost. Based on extensive review of related literature, the applicant proposed a novel method to use deep eutectic solvents (DES) as denitrifying agents to remove NO selectively from the flue gas via the specific interactions between DES and NO molecules. In this proposal, a series of advanced characterization instruments will be used to study the molecular interactions between NO and DES. Furthermore, the kinetics of NO absorption and desorption will be studied to elucidate the mechanisms of the selective NO absorption in DES and desorption from DES and the factors influencing the interactions between NO and DES. Finally, the DES with optimal chemical structure will be designed accordingly, which will provide fundamental knowledge for the design of new denitrifying agents and boost the development of high-performance and low-cost denitrification technologies.

燃煤电厂烟气中的氮氧化物是主要的大气污染物，也是我国大范围雾霾的主要成因。已有的烟气脱硝技术如选择性催化还原和非选择性催化还原等均具有一次性投资大、运行成本高等缺点。因此，研发新型高效烟气脱硝技术对我国氮氧化物的减排和雾霾治理具有十分重要的意义。NO 约占氮氧化物总量的95%，但对NO 的低成本、高效选择性脱除是目前尚未解决的难题。申请人在查阅大量文献基础上提出了利用新型的低共熔溶剂（DES）类离子液体作为脱硝剂，利用其与NO 分子间的选择性交互作用，实现烟气中NO 的选择性高效脱除。本项目将利用多种先进分析手段深入研究DES和NO 分子相互作用的本质，研究DES 选择性吸附NO 的动力学过程，揭示NO 吸附和脱附的规律和影响因素，实现DES化学结构和官能团的合理构建，从而为新型脱硝剂的设计及脱硝工艺技术的研发提供理论依据。

高效脱除燃煤烟气中NO是治理我国大范围雾霾必须解决的关键问题之一。目前工业生产中烟气脱硝技术存在投资成本高、易产生二次污染等问题。研发新型高效低成本烟气脱硝技术是我国面临的迫切任务。本项目提出了利用低共熔溶剂（DES）选择性吸收烟气中NO。对所制备的一系列羟基数量和不同碳链长度的低共熔溶剂（DES）进行物理性质方面的表征。在自制的烟气净化实验装置上，对低共熔溶剂（DES）选择性吸收烟气中NO的过程进行系统的研究。实验结果表明随着温度的升高，所测试的四乙基溴化铵-乙二醇DES、四丙基溴化铵-乙二醇DES、四丁基溴化铵-乙二醇DES这几种DES的粘度均呈现指数式衰减。随着温度的升高，样品的电导率逐渐增强。利用乙二醇-四丁基溴化铵低共熔溶剂通过范德华力力和氢键的作用能够有效吸收烟气中的NO。通过添加亚铁离子制备一系列铁基乙二醇-四丁基溴化铵低共熔溶剂（DES）样品发现能够同时脱除烟气中的SO2和NO气体，实现烟气一体化净化。低共熔溶剂经过多次再生循环后，仍保持较高脱硫脱硝效率，脱硫脱硝性能保持稳定。研究了DES选择性吸附NO的热力学和动力学过程，揭示了NO吸附和脱附的影响因素，实现了DES化学结构和官能团的合理构建。从而为新型脱硝剂的设计及脱硝工艺技术的研发提供理论依据。