The leakage accident of molten salt in the thermal storage tank will cause the shutdown and enormous economic losses of Concentrated Solar Power plants.This study investigates the heat transfer and flow characteristic...The leakage accident of molten salt in the thermal storage tank will cause the shutdown and enormous economic losses of Concentrated Solar Power plants.This study investigates the heat transfer and flow characteristic of commercial molten nitrates leaking in the thermal state porous foundation material.The migration width and depth of three molten nitrates,Solar Salt(60 wt%NaNO_(3)-40 wt%KNO_(3)),Hitec XL(7 wt%NaNO_(3)-45 wt%KNO_(3)-48 wt%Ca(NO_(3))_(2))and Hitec(7 wt%NaNO_(3)-53 wt%KNO_(3)-40 wt%NaNO_(2)),are obtained at different operating temperatures.Experimental results indicate that the temperature rising rate of foundation material in the nitrate leaking process has a trend of first increasing rapidly and then decreasing,and then it increases slightly as the depth increases.The temperature rising rate increases obviously with increasing operating temperature of the molten salt.With the increase of the operating temperature,the distances from the storage tank bottom to solid salt in foundation and the total migration depths both increase obviously,while the average migrating widths change slightly.At the same operating temperature,the temperature rising rate of the foundation material where Hitec XL and Hitec salt leak is significantly greater than that with Solar Salt,which is closely related to the melting points of molten salts.The migration depth of Hitec is 95.03%greater than that of Solar Salt and 19.11%larger than that of Hitec XL at the operating temperature of 300℃.Compared with Hitec XL,the leakage of Hitec with a smaller viscosity has a larger temperature rising rate and a wider and deeper transporting range during the leakage process.This work could guide the installation locations of the leak detection devices for high temperature storage tank and the environmental treatment of leaking accident.展开更多
The heat receiver is an essential part of the Concentrating Solar Power plant,directly affecting its operation and safety.In this paper,the Monte Carlo ray-tracing algorithm was introduced to evaluate a 50 MW(e)extern...The heat receiver is an essential part of the Concentrating Solar Power plant,directly affecting its operation and safety.In this paper,the Monte Carlo ray-tracing algorithm was introduced to evaluate a 50 MW(e)external cylindrical receiver’s thermal performance.The radiation heat flux concentrated from the heliostats field and the view factors between grids divided from the tubes were both calculated using Monte Carlo ray-tracing algorithm.Besides,an in-house code was developed and verified,including three modules of the view-factor calculation,thermal performance calculation,and thermal stress calculation.It was also employed to investigate the 50 MW(e)receiver,and the detailed 3D profiles of temperature and thermal stress in the receiver were analyzed.It was found that the molten salt was heated from 298℃to 565℃and the tube at the 50 MW(e)receiver’s outlet had a high temperature,while the high thermal stress came out at the receiver’s entrance.Finally,the over-temperature of the receiver was discussed,and an optimization algorithm was introduced.The tube wall temperature and film temperature at the overheated area matched the safety criteria,and the outlet molten salt temperature still reached 563℃after the optimization process,with only 2℃dropped.展开更多
基金This work was supported by the National Natural Science Foundation of China(52036008).
文摘The leakage accident of molten salt in the thermal storage tank will cause the shutdown and enormous economic losses of Concentrated Solar Power plants.This study investigates the heat transfer and flow characteristic of commercial molten nitrates leaking in the thermal state porous foundation material.The migration width and depth of three molten nitrates,Solar Salt(60 wt%NaNO_(3)-40 wt%KNO_(3)),Hitec XL(7 wt%NaNO_(3)-45 wt%KNO_(3)-48 wt%Ca(NO_(3))_(2))and Hitec(7 wt%NaNO_(3)-53 wt%KNO_(3)-40 wt%NaNO_(2)),are obtained at different operating temperatures.Experimental results indicate that the temperature rising rate of foundation material in the nitrate leaking process has a trend of first increasing rapidly and then decreasing,and then it increases slightly as the depth increases.The temperature rising rate increases obviously with increasing operating temperature of the molten salt.With the increase of the operating temperature,the distances from the storage tank bottom to solid salt in foundation and the total migration depths both increase obviously,while the average migrating widths change slightly.At the same operating temperature,the temperature rising rate of the foundation material where Hitec XL and Hitec salt leak is significantly greater than that with Solar Salt,which is closely related to the melting points of molten salts.The migration depth of Hitec is 95.03%greater than that of Solar Salt and 19.11%larger than that of Hitec XL at the operating temperature of 300℃.Compared with Hitec XL,the leakage of Hitec with a smaller viscosity has a larger temperature rising rate and a wider and deeper transporting range during the leakage process.This work could guide the installation locations of the leak detection devices for high temperature storage tank and the environmental treatment of leaking accident.
基金The Project is supported by the Innovative Research Groups of the National Natural Science Foundation of China(51621005).
文摘The heat receiver is an essential part of the Concentrating Solar Power plant,directly affecting its operation and safety.In this paper,the Monte Carlo ray-tracing algorithm was introduced to evaluate a 50 MW(e)external cylindrical receiver’s thermal performance.The radiation heat flux concentrated from the heliostats field and the view factors between grids divided from the tubes were both calculated using Monte Carlo ray-tracing algorithm.Besides,an in-house code was developed and verified,including three modules of the view-factor calculation,thermal performance calculation,and thermal stress calculation.It was also employed to investigate the 50 MW(e)receiver,and the detailed 3D profiles of temperature and thermal stress in the receiver were analyzed.It was found that the molten salt was heated from 298℃to 565℃and the tube at the 50 MW(e)receiver’s outlet had a high temperature,while the high thermal stress came out at the receiver’s entrance.Finally,the over-temperature of the receiver was discussed,and an optimization algorithm was introduced.The tube wall temperature and film temperature at the overheated area matched the safety criteria,and the outlet molten salt temperature still reached 563℃after the optimization process,with only 2℃dropped.
