基于风险指引的光热电站高温熔盐储罐结构强度设计研究

RISK-INFORMED STRENGTH DESIGN OF HOT MOLTEN SALT STORAGE TANK FOR CSP PLANTS

高温熔盐储罐是太阳能光热电站中关键储能设备。同类设备的事故表明,基于一般强度设计规范的储罐存在周期性开裂风险。以某100 MW塔式光热电站为例,在高温结构强度设计理论的基础上,引入风险指引型设计方法,逆向计算风险源的量化控制指标。结果表明:罐底等效摩擦因数大于0.65时,储罐将在开工升温阶段产生棘轮损伤;当沙层大于60 mm时,引起的地基沉降将导致储罐注满后侧壁的瞬时开裂;进口熔盐温度波动若超出-20℃~+25℃,则会引发罐底高周疲劳断裂或屈曲失效。同时,建议通过适当增加罐底中心高度(<29 mm)以预防热应力失效。

Hot molten salt storage tank is the key energy storage equipment in solar thermal power stations. The accidents of similar equipment indicates that there is a risk of periodic cracking for storage tanks based on general strength design specifications. Based on the high-temperature structural strength design theory, risk-informed design methods were introduced to a 100 MW CSP plant. Quantitative control indicators for risk sources were reversely calculated. The results show that when the equivalent friction coefficient of bottom plate is greater than 0.65, the tank could have ratchet damage during heat-up stage. When the thickness of sand layer is greater than 60 mm, the sidewall of the storage tank could be instantaneously fractured. The range of temperature fluctuation should be limited between-20℃ and +25℃ to avoid high cycle fatigue fracture and buckling. Meanwhile, it is recommended to appropriately increase the center height of the tank bottom(<29 mm) to prevent thermal stress failure.