太阳能与燃煤机组锅炉冷端NOx脱除耦合机理及系统集成

With the strict energy saving and pollutant removal limits, it is of great significance to keep power plants clean and efficient. Taken the great temperature area matching of parabolic trough solar energy and NOx removal of boiler cold end in coal-fired power plants into consideration, coupling mechanism and system integration between solar energy and NOx removal of boiler cold end in coal-fired power plants is studied in this project, from the crossing fields of thermodynamics and chemical. This project focuses on the following three key scientific issues: generalized energy consumption characteristics and theoretical minimum energy consumption of NOx removal in boiler cold end of coal-fired power plants, influence mechanism on both solar energy utilization and NOx removal brought by common parameters, and complementary property and coupling mechanism between solar energy and NOx removal in boiler cold end. By theoretical analysis, chemical dynamics simulation, thermodynamic process simulation and experiment, the project explores the generalized energy consumption and reduction characteristics of NOx removal process in boiler cold end, and reveals the coupling mechanism between solar energy utilization and NOx removal. On this basis, optimized integration systems with great performance, combining the solar energy utilization and NOx removal, are proposed. The achievements provide crucial theoretical support for solar energy efficient utilization and NOx effective removal with low energy consumption in coal-fired power plants. Besides, it also provides feasible technical route for clean and efficient power generation.

为了应对日益严格的节能减排要求，实现我国发电系统的清洁高效协同，本课题关注槽式太阳能与燃煤机组锅炉冷端NOx脱除温区的良好匹配现象，立足于热力学与化学的学科交叉，针对太阳能与燃煤机组锅炉冷端NOx脱除耦合机理及系统集成进行研究。课题紧密围绕“燃煤发电系统锅炉冷端NOx脱除的广义能耗特性与理论最低能耗”、“共性参数对于太阳能热利用与NOx脱除的协同影响机制”、“太阳能与锅炉冷端NOx脱除的互补特性及耦合机理”三个科学问题，通过理论分析、化学动力学模拟、热力学流程模拟和实验验证，针对锅炉冷端NOx脱除过程广义能耗特性与还原特性开展研究；凝练太阳能与锅炉冷端NOx脱除的耦合机理；在此基础上，开拓整体性能优异的太阳能与NOx脱除优化集成系统。本项目的研究成果将为燃煤发电系统中太阳能高效利用协同NOx低能耗高效脱除提供理论支撑，同时也为实现更清洁、更高效的发电模式提供可行的技术选项。

为了实现我国清洁、高效、低碳发电，本项目对太阳能与燃煤机组锅炉冷端NOx脱除的耦合集成开展研究，课题立足于热力学与化学的学科交叉，针对“燃煤机组锅炉冷端NOx脱除过程广义能耗特性与还原特性分析”、“太阳能与锅炉冷端NOx脱除耦合机理”、“太阳能与NOx脱除系统集成优化”三个内容进行了研究，首先通过数据分析和热力学分析，获得了温度对于NOx还原脱除特性的影响规律，以及锅炉冷端NOx脱除的广义能耗特性，提出了协同优化方案，将NOx脱除效率提升了6.5个百分点，同时将附近空气预热过程和给水加热过程的能耗分别降低1.5 MWth和1.4 MWth，研究结果揭示了锅炉冷端NOx脱除过程广义能耗特性与还原特性，为NOx低能耗协同高效脱除提供了有效的路径。在后面的研究中，探索了太阳能与锅炉冷端的能量匹配原则，研究了太阳能与锅炉冷端在多工质、大温区条件下的耦合机制，结合实际案例机组，通过耦合参数优化，太阳能与给水加热过程的耦合可实现8.5 MWe的太阳能发电功率，而太阳能与空气预热过程的耦合可以有效降低空气预热流程㶲损失36.6%，研究结果揭示了太阳能与锅炉冷端的耦合机理。此外，结合实际工程约束，提出利用槽式太阳能驱动蒸汽喷管，耦合原煤干燥的系统集成模式，将64.2 MWth的槽式太阳能高效转换为燃料化学能。研究结果揭示了太阳能、工质物理能、燃料化学能之间的转换机理。最后，将太阳能与锅炉冷端SCR脱硝过程进行耦合集成，以机组整体能耗水平和NOx脱除效率最优为原则，开拓了清洁高效协同的太阳能与锅炉冷端NOx脱除优化集成系统，集成系统能够实现25.3%的光电转换效率，同时有效降低NOx排放19.8 g/s。研究结果揭示了太阳能与锅炉冷端NOx脱除的互补特性及耦合机理，开拓了整体性能良好的系统集成方案，为我国清洁、高效、低碳发电提供了技术选项。