燃煤发电系统烟气热利用与污染物脱除一体化集成机理

With the strict pollutant removal limits, it is of great significance to resolve the contradiction between the extra energy consumption by the pollutant reduction and the energy conservation in the coal-fired power plant. From the crossing fields of energy, chemical and environmental engineering, this project combines the flue gas waste heat utilization with the pollutant removal based on energy cascade utilization and process complementation. By theoretical analysis, process simulation, process experiment and field test, the project studies the energy and state characteristics of the exhaust flue gas in the coal-fired power plant, analyzes the effects of the key state parameters on the condensation and separation characteristics of the pollutants in the flue gas, explores the complementary relationship between the flue gas waste heat and the pollutant removal, and conducts the integration mechanism and optimization measures of flue gas waste heat utilization and pollutant removal in the coal-fired power plant with the purpose of environmental protection and energy conservation. On this basis, various promising and comprehensive integrated schemes, combining the flue gas heat utilization with the pollutant removal, are proposed in this project. The achievements provide crucial theoretical support for low energy consumption of the pollutant removal and in-depth utilization of the waste heat in the coal-fired power plant. Besides, it also provides a feasible technical route for a clean and high-efficiency coal-based sustainable system.

为应对燃煤发电系统所面临的日益严格的污染物脱除要求、同时解决污染物减排附加能耗与电站深度节能之间的尖锐矛盾，本项目从能源、化工与环境的交叉领域出发，从燃煤发电系统烟气热利用与污染物脱除中能的梯级利用与流程互补特性入手，通过理论分析、流程模拟、关键过程实验和现场试验，研究燃煤发电系统尾部烟气的状态表征与能量特性，分析关键状态参数对烟气中主要污染物的凝聚状态、分离特性等的影响规律；探求烟气热利用流程与污染物脱除流程的互补特性与耦合关系；研究兼顾环保与节能目标的燃煤发电系统烟气热利用与污染物脱除的一体化集成机理与优化方法。在此基础上，开拓多种具有良好应用前景和综合性能的燃煤发电系统烟气热利用与污染物减排一体化集成方案。本项目研究成果将为燃煤发电系统污染物的低能耗协同脱除与深度余热利用提供重要的理论支撑，为实现更高效、更清洁的新型可持续煤基能源系统提供可能的技术选项。

为应对燃煤发电系统所面临的日益严格的污染物脱除要求、同时解决污染物减排附加能耗与电站深度节能之间的尖锐矛盾，本项目从燃煤发电系统烟气热利用与污染物脱除中能的梯级利用与流程互补特性入手，通过理论分析、流程模拟、关键过程实验和现场试验展开研究：.1）针对烟气中主要污染物的凝聚、脱除特性规律进行了研究，获得烟气中主要污染物脱除的能耗；归纳总结现有燃煤电站污染物脱除手段下进一步提高污染物脱除效率的优化路线。.2）火电生产过程污染物脱除流程的能耗特性分析与节能优化。基于1000 MW机组：针对NOx，提出了太阳能辅助燃煤电站SCR脱硝系统，在50%负荷下可提高脱硝效率7.9%；提出利用高温烟气作为热源驱动尿素热解的SCR优化系统，相较于电加热、蒸汽加热驱动，可分别降低供电煤耗0.43、0.13 g/kWh。针对SOx，提出浆液循环泵与氧化风机的运行优化策略，可有效降低脱硫能耗。针对“白色烟羽”，提出烟气余热显热与潜热联合回收系统，提升全厂热效率0.65%的同时可将排放净烟气温度提升至82.5℃、回收13.9 kg/s水分。.3）烟气热利用与污染物脱除的一体化集成机理研究及优化设计。基于1000 MW机组，提出省煤器分级布置的机炉深度耦合系统，提升全厂热效率0.50%的同时将脱硝效率提升8.5%（50%负荷）、脱硫水耗降低1082.5 t/d（100%负荷）；提出同时提升能源利用效率和污染物稀释能力的优化系统，降低供电煤耗1.13 g/kWh的同时提升净烟气排放温度至80℃、降低除尘烟气流速8.2%、提高SO3脱除效率29.5%、节约脱硫水耗57.5 t/h。.4）搭建真实烟气特性分析实验台；完成烟气重金属离线取样测量实验，研究了重金属（汞）的凝聚特性与脱除规律；完成多种材料腐蚀特性、电化学腐蚀特性测量实验；氟塑料换热器的传热实验及优化布置方式实验作为一体化集成设计的配套研究，可提高集成方案在工程理论上的可行性。.本项目研究广泛，成果丰富，将为燃煤发电系统污染物的低能耗协同脱除与深度余热利用提供重要理论支撑，为实现更高效、更清洁的新型可持续煤基能源系统提供可能的技术选项。