燃煤烟气SO3迁移转化与吸收控制基础研究

作为重要基础能源，煤的清洁高效利用是我国社会发展的长期需求。随着常规污染物超低排放的实施，燃煤生成SO3带来的设备腐蚀和环境污染问题凸显。研究SO3在烟气系统中的迁移转化与控制，对于燃煤污染物减排及系统稳定运行具有重要的意义。本项目结合烟气环境特征，探索 H2SO4与H2O的二元均相凝结、在飞灰表面的异相凝结以及SO3/ H2SO4与飞灰的反应特性，基于均、异相凝结机理与反应动力学分析，建立描述烟气中SO3迁移转化的数学模型，分析关键参数对硫酸雾生成特性的影响，揭示不同参数区间硫酸雾生成的主要控制机制，为预测SO3在排放烟气中的物态分布与制定调控策略提供理论指导；以碱土金属类及亚硫酸盐类吸收剂为代表，研究SO3、SO2/ O2共存时与吸收剂的竞争反应特性，结合反应过程中间产物的多维表征，探明其竞争反应机理并建立动力学模型，为高效吸收剂的开发与喷吸收剂脱SO3技术的优化提供基础支撑。

As an important basic source of energy, the clean and efficient utilization of coal is a long-term demand for the development of our society. With the ultra-low emission of conventional pollutants, the problems of equipment corrosion and environmental pollution caused by SO3 emission are highlighted. SO3 will undergo complex physical transformation and chemical conversion in the process of flue gas cooling. But the existing theory cannot predict the behavior characteristics and coupling mechanism of various pathways. This project intends to experimentally study the binary homogeneous condensation of H2SO4 and H2O, the heterogeneous condensation of H2SO4 on the surface of fly ash, and the chemical reactions between SO3/ H2SO4 and fly ash in flue gas. Based on condensation theory and chemical kinetics analysis, mathematical models will be built for above pathways. The formation characteristics of sulfuric acid mist will be analyzed and their coupling mechanism will be revealed, which provide theoretical guidance for ascertaining the occurrence of SO3 in the emitted flue gas and for developing SO3 emission control strategy. Injecting absorbent can control SO3 emission, while its efficiency is greatly affected by the competitive absorption of other components in flue gas. The competitive reactions between SO3, SO2/ O2 and two kind of typical absorbents will be studied experimentally. The physical and chemical properties of the intermediate products will be characterized. The competitive reaction mechanism and the chemical kinetics models will be proposed, to support the development of new absorbent and economical and efficient deSO3 technology.