Research On Design Of Molten Salt Heat Storage Tank

Solar thermal power generation is easy to combine with thermal storage system,so thermal storage technology is widely used in solar photothermal power generation.Through thermal storage system,the power station can output electricity smoothly,which is the focus of development at home and abroad.However,due to the influence of solar rotation and weather,solar energy is intermittent.In order to ensure that the power plant can continuously and steadily output electricity,thermal storage system is essential.In the thermal storage system,molten salt thermal storage tank is the core equipment.Studying the temperature distribution law and the influencing factors of heat loss during the cooling process of molten salt thermal storage tank is helpful to optimize the design and operation control of molten salt thermal storage tank in photothermal power station,and to improve the energy conversion efficiency.In this paper,the molten salt thermal storage experimental platform of China Electric Power Investment Group Northeast Energy Saving Technology Co.,Ltd.is used to carry out various research work.The key equipment of the thermal storage system,molten salt thermal storage tank,is mainly studied.Using finite element analysis software ANSYS,the following aspects are simulated and studied: the temperature distribution law and the influencing factors of heat loss of molten salt the rmal storage tank under different combination of thermal insulation materials and different thickness of thermal insulation layer,the best combination of thermal insulation materials and thickness of each thermal insulation material are analyzed and determined;the molten salt thermal storage tank has different storage temperature and different height.The optimum storage temperature of the heat storage system and the reasonable ratio of height to diameter of molten salt heat storage tank are determined by analyzing the influence factors of diameter ratio,temperature distribution at different liquid levels and heat loss.The influence of ambient temperature and wind speed on the heat loss of molten salt heat storage tank is also discussed.Through FLUENT ca lculation,the temperature distribution law of molten salt heat storage tank under different working conditions was obtained.According to the measured data in the experiment,the following main conclusions are obtained: the best thermal insulation materia l combination is 0.01 m thick nanometer and 0.3m thick mineral cotton;6t molten salt is heated to 420℃ into molten salt storage tank,and the natural cooling temperature is reduced to 317℃ for 90 hours,so that the longest time interval for molten salt to not solidify is 104 hours;with the increase of storage temperature,the heat loss is obvious.The reasonable storage temperature is 370℃~410℃.In this paper,the temperature distribution law of molten salt thermal storage tank and the influencing factors of heat loss are simulated and analyzed,which provides guidance for the design of thermal storage tank,thermal insulation design of thermal storage tank and scholars engaged in thermal storage technology research.