基于高温熔盐储热系统的火电机组深度调峰方案对比及分析

Comparison and Analysis of Deep Peak Shaving Schemes for Thermal Power Units based on High-temperature Molten Salt Heat Storage System

为构建以新能源为主体的电力系统,亟须提高火电机组灵活性,火电机组与熔盐储热系统进行耦合能够强化调峰灵活性和调峰经济性。本文以某670MW电厂为依托,基于Ebsilon对该机组的4种熔盐—火电耦合系统改造方案进行仿真计算,并对比分析了各种方案的热力性能、调峰性能、环保性能及改造难度。结果表明:高温熔盐和低温熔盐储热组合方式有效克服了单种熔盐工作温度受限的问题,能够增强燃煤机组的调峰能力和循环效率;配置电加热器后熔盐能够以目标温度存储于热罐,热电转化效率得到提高,还额外平抑了部分可再生能源的不稳定性;通过低压缸零出力管道进行中压缸排汽蓄热和电加热提温的方案改造量最小、控制方式最为成熟灵活,能够兼顾调峰调频、节能环保和改造难度等方面的需求。

In order to build a power system with new energy as the main body,it is urgent to improve the flexibility of thermal power units.Coupling thermal power units with molten salt heat storage system can strengthen the flexibility and economy of peak shaving.Based on a 670 MW power plant and Ebsilon,this paper simulates and calculates the retrofit scheme of 4-unit′s molten salt and 1-thermal power coupling system,and compares and analyzes the thermal performance,peak shaving performance,environmental protection performance and retrofit difficulty of various schemes.The results show that the combination of high temperature molten salt and low temperature molten salt heat storage effectively overcomes the problem of limited working temperature of a single molten salt,and can enhance the peak shaving capacity and cycle efficiency of coal-fired units;after the electric heater is configured,the molten salt can be stored in the heat tank at the target temperature,and the thermoelectric transformation efficiency is improved,which also absorbs the instability of some renewable energy sources;the scheme of steam exhaust and heat storage of intermediate pressure cylinder and electric heating and temperature raising through zero output pipeline of low pressure cylinder has the smallest transformation amount,the most mature and flexible control mode,and can meet the needs of peak shaving and frequency modulation,energy conservation and environmental protection and transformation difficulty.