熔盐光热发电系统安全风险识别及防控措施

Safety risk identification and prevention measures of molten salt solar thermal power generation system

通过模拟和试验研究的方法,分析了熔盐光热发电系统中的安全风险因素。结果表明,聚光集热系统中的光危害、高热流密度、高温环境和熔盐腐蚀泄漏等是主要风险因素。槽式光热系统热流密度峰值达4.37×10^(4)W/m^(2),平均值超过1.8×10^(4)W/m^(2),塔式光热系统热流密度高于槽式,错误聚焦极易引发火灾和烫伤事故。熔盐在高工作温度(120~600℃)下会降低系统的材料强度,对系统钢材腐蚀显著,产生安全事故。混合硝酸盐在3 m/s流速下,对不锈钢316和321的腐蚀失量分别为0.023 kg/m^(2)和0.024 kg/m^(2),与静态腐蚀相比分别增加了44%和35%。混合碳酸盐对不锈钢304的静态腐蚀经360 h后,质量损失达0.236 kg/m^(2)。为防控这些风险,提出了包括光热镜场防护、工质火灾事故防护、消防设计和腐蚀泄漏防护等措施。

Safety risk factors in molten salt solar thermal power generation systems were analyzed through simulation and experimental research methods.The results indicate that the main risks include optical hazards,high heat flux density,high-temperature environments,and corrosion leakage of molten salts within the concentrating solar power system.The peak heat flux density in trough solar thermal systems reaches 43.7×10^(4)W/m^(2),with an average exceeding 1.8×10^(4)W/m^(2).The heat flux density in tower solar thermal systems is higher than that in trough systems,and incorrect focusing can easily lead to fires and scalding accidents.Molten salts,operating at high temperatures(120~600°C),can reduce the strength of system materials and cause significant corrosion to the steel components,leading to safety incidents.At a flow rate of 3 m/s,mixed nitrates increase the corrosion weight loss rate of stainless steels 316 and 321 to 0.023 kg/m^(2)and 0.024 kg/m^(2),respectively,which is a 44%and 35%increase compared to static corrosion.After 360 hours of static corrosion,mixed carbonates cause a mass loss of 0.236 kg/m^(2)for stainless steel 304.To prevent and control these risks,measures including protection of the solar mirror field,fire accident protection for working fluids,fire protection design,and corrosion leakage protection have been proposed.