含硫废气改性炭基吸附剂烟气脱汞及再生机理研究

Mercury sorbents regeneration and mercury recovery from coal-fired flue gas have become hot research topics for clean coal utilization and sustainable development. This project proposes a novel processing technology routine for activating mercury sorbents from carbon-based materials (activated carbons, biomass cokes and petroleum cokes). The sulfur contained effluent gases (SO2/H2S) are selected as the modifying agent for preparing the economic, effective and regenerable sorbents. The mechanisms of mercury adsorption, desorption, recovery, as well as the mechanisms of sorbents activation and regeneration by sulfur contained effluent gases will be thoroughly studied. The interaction mechanism of mercury adsorption, desorption, recovery and the cycle mercury adsorption ability of the regenerable sorbents will be further investigated. The kinetic models including mass transfer, mercury adsorption mercury desorption and chemical reactions on carbon-based sorbents surface will be established. Theoretical researches on chemical modification, mercury adsorption, desorption and recovery as well as sorbents regeneration on molecular-level reactions by utilizing the quantum chemistry and transition state theory will be carried out. Bench-scale experiments will be conducted in order to validate the theoretical solutions. It is hopefully to develop an advanced technique for high efficient mercury removal and sorbents regeneration with independent intellectual property and future industrial application in coal-fired power plants through this research project.

燃煤烟气脱汞吸附剂的再生及汞资源的回收利用是煤炭清洁利用及可持续发展的重要研究课题。本项目提出以工业含硫废气（SO2/H2S）改性炭基吸附剂（活性炭、生物质焦、石油焦），实现高效脱汞、吸附剂再生、汞脱附回收及可再生脱汞吸附剂循环脱汞的工艺技术路线。系统深入地研究SO2/H2S改性、汞吸附、汞脱附、汞回收及吸附剂再生的机理。揭示SO2/H2S改性炭基吸附剂汞吸附、汞脱附、汞回收及吸附剂再生过程中的相互作用及影响机制。获得可再生脱汞吸附剂烟气循环脱汞特性及规律。建立SO2/H2S改性炭基吸附剂烟气脱汞及再生过程的传质-吸附-脱附反应动力学模型。基于量子化学和过渡态理论建立炭基吸附剂表面改性/汞吸附/汞脱附/吸附剂再生的微观反应机制。在实验室规模试验台上进行机理验证试验。以期孵化出具有我国自主知识产权和工程实用价值的新型燃煤电厂烟气脱汞和吸附剂再生技术。

本项目提出硫改性炭基和非炭基材料制备可再生脱汞吸附剂，实现燃煤烟气高效脱汞、吸附剂活化再生和循环脱汞的工艺技术路线。系统深入地研究可再生脱汞吸附剂的改性机理和制备方法，阐明硫形态对汞吸附和汞脱附的机理，采用载硫再生方法探讨吸附剂的失活机制及活化再生的机理，获得可再生吸附剂的循环脱汞特性，采用量子化学原理方法深入探究硫形态对汞吸附脱除的微观化学反应机制。主要研究内容和研究成果概况如下：以活性炭、高硫石油焦为炭基吸附剂材料，以Fe2O3为磁性吸附剂材料，以单质硫、SO2、H2S为改性剂，以直接热再生、程序升温热再生、载硫热再生等方法，系统深入的研究了单质硫、SO2、H2S改性炭基吸附剂/磁性吸附剂的制备、汞吸附、汞脱附、吸附剂再生、循环脱汞过程的机理和影响因素；探究了吸附剂的微观形貌、理化特性、含硫官能团、含氧官能团、硫形态等在汞吸附、汞脱附、吸附剂再生、循环脱汞过程中的变化以及与汞脱除的本构特征；阐明了硫改性炭基吸附剂、磁性吸附剂在不同改性方法、烟气组分、再生方法中的脱汞特性、影响规律，以及汞形态、硫形态、活性位点的迁移转化机制；建立了汞吸附/汞脱附/吸附剂活化再生/吸附剂循环脱汞过程的吸附热力学、吸附动力学、吸附平衡和量子化学模型；基于饱和分子簇模型构建了噻吩硫、硫化物、硫烷硫及单质硫等不同含硫官能团的分子构型，从理论上阐述了Hg在不同含硫官能团表面的微观吸附机理，提出了Hg0在硫烷硫官能团和单质硫分子表面化学吸附生成HgS的反应路径。项目研究成果为硫改性制备可再生脱汞吸附剂的研究和应用提供了坚实的实验和理论基础。