基于热经济学的热力系统主蒸汽压力-排汽压力联合优化

Joint optimization of main steam pressure and exhaust steam pressure in thermal system based on thermoeconomics

为提升机组参与调峰时的热经济性,确定不同工况下热力系统发电成本,提出一种热力系统主蒸汽压力-排汽压力联合优化热经济学模型。该模型在算法设计中采用内外3层的迭代循环逻辑,从机理层面分析热力系统各参数间耦合关系,获得参数扰动后系统全部汽水参数和各级组通流量校正值。应用该数据完成热经济学指标计算与系统优化。获得不同负荷不同环境温度条件下主蒸汽压力与凝汽器真空的联合优化解。对比计算结果得出:主蒸汽压力与排汽压力联合优化解优于主蒸汽压力单独优化解;热力系统的发电成本随负荷的升高而减小、随环境温度的升高而增大;热力系统在冬季经济性更好。建议火电机组在制定上网电价时考虑季节因素对系统发电成本的影响。

In order to improve thermal economy of the unit participating in peak shaving and determine the power generation cost of thermal systems under different operating conditions,a thermoeconomic model for combined optimization of main steam pressure and exhaust steam pressure of the thermal system is proposed.In this model,the internal and external three-layer iterative cycle logic is used in the algorithm design,tiie coupling relationship among the parameters of the thermodynamic system is analyzed from mechanism level,and all the steam-water parameters of the system and the calibration values of flow rate at all units after the parameter perturbation were obtained.The data are used to calculate the thermoeconomic indexes and optimize the system.The joint optimization solution of the main steam pressure and condenser vacuum at different loads and ambient temperatures was obtained.The results show that,the combined optimization solution of the main steam pressure and exhaust steam pressure is better than the single optimization solution of the main steam pressure.The generation cost of the thermal system decreases with the increase of unit load and increases with the ambient temperature.The thermal system is more economical in winter.It suggests that the influence of seasonal factors on the generation cost of the system should be taken into account when setting the generation price of thermal power units.