"双碳目标"背景下,煤电机组将长期作为主力调峰电源,保障电网安全稳定.储热是提升煤电机组灵活性的重要手段,但煤电耦合储热系统的运行特性尚不明确,不同储热技术与煤电机组耦合适应性亟待研究.为此,该文构建600 MW煤电-90 MW显热/潜热/热化学储热3种耦合系统,详细考察系统储/释热过程调峰能力及热力学性能,并基于优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)综合评价,明确最优耦合方案.研究发现,储热过程,Ca(OH)2/CaO热化学储热的调峰容量、调峰深度及㶲效率均优于热水及熔融盐储热,而释热过程熔融盐储热性能最优;通过TOPSIS综合评价法确定热储热方案均为抽取主蒸汽作为热源,最佳释热方案均为以#2 高加进水为冷源,同时确定煤电耦合熔融盐储热为最佳系统耦合方案.相关研究结论可为构建煤电耦合储热调峰系统提供一定的理论和数据支撑.
Research and Evaluation on the Flexible Peaking Performance of Coal-fired Power Plants Coupled With Thermal Storage
In the context of achieving carbon peaking and carbon neutrality,coal-fired power will be the main peak-shaving power supply for a long time to ensure the safety and stability of the power grid.Thermal storage is an important method to improve the flexibility of coal-fired power plants,but the operation characteristics of coal-fired power coupled thermal storage systems are still unclear,necessitating urgent research on the adaptability of various thermal storage technologies in combination with coal-fired power plants.In this study,a 600 MW coal-fired power plant is integrated with a 90 MW thermal storage unit,of which sensible,latent,and thermochemical heat storage are considered.The peak regulation ability and thermodynamic performance of the system are investigated in the heat storage/release processes,and the optimal coupling scheme is determined following the Technique for Order Preference by Similarity to an Ideal Solution(TOPSIS)method.In comparison with hot water and molten salt heat storage,Ca(OH)2/CaO thermochemical heat storage has the best peak shaving capacity,peak shaving depth,and exergy efficiency,while the molten salt heat storage performs best in the heat release process.By evaluating with TOPSIS method,the best heat storage scheme for hot water,molten salt and Ca(OH)2/CaO thermochemical heat storage is to extract the main steam as the heat source,and the best heat release scheme is using No.2 high-pressure water as the cold source.Besides,the coal-fired power coupling molten salt heat storage is the best coupling scheme.The relevant research conclusions can provide theoretical and data support for the construction of coal-fired power coupling heat storage peak shaving systems.
coal-fired power plantthermal storagepeak shaving capacitythermodynamic performancemolten saltTOPSIS
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