氧硫氯碳对高储氧改性活性焦脱除煤气中汞的耦合作用机制

When developing advanced and efficient coal conversion technology, one of the urgent problems which need to be solved is to achieve the efficient and economical removal of elemental mercury (Hg0) from syngas. On the basis of that mercury removal could be promoted with the presence of oxygen, metal impregnated activated coke (AC) with large oxygen storage capacity was employed to capture Hg0 from syngas. To generate the active adsorption sites, activated coke was modified by the oxygen enriched metal ions; In order to establish the regulation mechanism of active group and microscopic structure, the mercury species were investigated at the atomic scale with advanced theory and test method such as quantum chemistry, synchrotron radiation and catalytic chemistry. The competition and cooperation mechanism of elements O-S-Cl-C-Hg-Ce/Mn/Co was proposed and the capture, conversion and migration characteristics of mercury were investigated; The regeneration mechanism of sorbents and adsorption stability were revealed to solve the key scientific problems in the process of gas mercury control. The implementation of the project has practical and scientific significance for the control of heavy metal in syngas, the development of advanced coal conversion technologies as well as the large-scale use of additional product from coal.

实现煤气中重金属汞的高效、经济脱除是发展先进高效煤转化利用技术急需解决的问题之一。本项目根据还原性气氛下汞的脱除在有氧协助条件下效率大大提高的特点，提出了采用具有强大储氧性能的金属改性廉价活性焦吸附剂脱除煤气中汞的新思路。采用富氧金属离子对活性焦进行改性活化处理，以吸附剂表面活性吸附位的生成为突破点，结合量子化学、同步辐射、催化化学等诸多先进理论与测试方法，在原子尺度上对吸附产物中汞的赋存状态和配位壳层信息进行分析，明确活性焦表面有效活性基团以及微观构造调控规律；考察汞在复杂气体环境下的捕获、转化、迁移特性，揭示吸附材料表面O-S-Cl-C-Hg-Ce/Mn/Co各元素相互竞争、协同作用机制；获取污染物吸附稳定性及吸附剂失活再生规律，解决煤气中汞控制过程中的关键科学问题。该项目的实施对于煤气中重金属元素的控制、先进煤转化技术的发展以及煤制附加产品的大规模利用都具有重要的现实与科学意义。

本项目在模拟煤气气氛中研究了过渡金属改性活性焦脱除汞污染物的机理研究。分析了吸附剂孔隙的分布特性和表面活性吸附位点的迁移规律，测试了Ce/Co/Mn等过渡金属在煤气气氛下脱汞性能最佳的配比，最高脱汞效率可达92%。发现煤气气氛的各组分(H2/CO/H2S/HCl等)对活性氧的竞争、协同机制是以生成和消耗活性氧与活性硫为核心，并利用密度泛函理论模拟计算了H2S在活性焦表面活性位点的吸附分解过程，以及产物活性硫与单质汞结合成稳定HgS的反应过程，建立了碳-汞-活性组分三元体系的气-固反应模型，解决了还原性气氛汞污染物控制的关键科学问题。考察了改性吸附剂表面汞的赋存形态及其热稳定性，在汞再生实验中发现CeCo双金属吸附剂有良好的再生性能，提供了脱汞吸附剂制备的新方向。本项目获得了实验室规模的吸附剂制备、污染物脱除以及吸附剂再生工艺流程，研究成果对先进煤转化技术的发展以及煤气中重金属元素的控制具有指导意义。